ARTICLE | doi:10.20944/preprints202112.0497.v1
Subject: Social Sciences, Education Keywords: higher education; international students; leadership and governance; SEM; STEM; sustainable development; sustainability
Online: 31 December 2021 (09:39:26 CET)
Attracting and retaining international students has been widely discussed in higher education settings. Increasing the number of international students has become an indispensable strategy for national and global competition. This study focuses on effective strategies and international students' issues regarding satisfaction in the most popular STEM (science, technology, engineering, and mathematics) programs. We designed a structural equation modeling (SEM) method to determine the effect of institutional mediation between push factors and satisfaction factors for the development of better strategies by which to attract and retain international students. Taking Taiwan as an example, this study employed a self-designed questionnaire to collect data: 485 degree-seeking international students in STEM programs were invited and successfully participated in this study during spring 2021. IBM SPSS 26 and AMOS 26 (Analysis of Moment Structure) were used to carry out the data analysis. We employed reliability, factor, and SEM analyses. This study assumed that the impact of push factors can be modified by institutional situations and result in international students’ satisfaction with their learning and environment and regarding migration policy. The results revealed that the predictors, mediation, and criteria were significant at the 0.05 or 0.01 levels. The findings suggest that push factors impact international students’ satisfaction when using institutional leadership and international strategy. The results of the bootstrap with a generalized least square method showed that the SEM model fit in 2000 bootstrap samples. The effect of institutional mediation can provide useful information for STEM programs to boost their future recruitment and retention strategies. This study provides an innovative approach to the detection of issues among international students in specific programs. These findings can enrich our knowledge regarding attracting and retaining global students in higher education settings.
ARTICLE | doi:10.20944/preprints201901.0219.v2
Subject: Social Sciences, Education Keywords: STEM for sustainability; early childhood education; English picture books, Chinese toddlers
Online: 27 February 2019 (08:42:09 CET)
Changes in curricula, publication policy and information technology, notably in China have led to concentrations in the role of STEM (science, technology, engineering and mathematics) education in early childhood and applauded to proliferations of imported up-to-date reading materials and mobile apps in English. This paper proposes a longitude study of a Chinese toddler learning STEM by reading picture books and playing with tablet and suggests new horizons in parenting and in STEM education during children's early years. The present study carried out from 2016, when the participant reached one year old, eligible to learn to speak and to concentrate on the picture books read by parents who had filled a language background questionnaire with information on themselves and the participant. Tablet playing brought about for the two-year-old toddler and collections of STEM books in English was added for the second year. Data collection lasted for two years with an iLab video camera, capturing utterances and motions for five minutes per week transcribed by VoiceScript software. Tests were given quarterly at private home by tapping in mobile app "Bilingual Child Learning" which consists of 20 basic STEM themes before scores were collected. Findings indicate that (1) it is accessible for children of very early years to be engaged in English STEM resources, (2) kids' limited English dominance does not impede learning STEM, (3) and to think in English in early STEM contributes to children's English.
ARTICLE | doi:10.20944/preprints202211.0367.v1
Subject: Social Sciences, Education Keywords: Sustainable gender equality; self-efficacy; gender mainstreaming; STEM higher education; STEM student teachers’ perceptions; scale validation, Spain, Creece
Online: 21 November 2022 (03:38:01 CET)
In the context of the Education-2030 Framework for Action, an important goal for initial STEM teacher education is to provide professional development on equality and gender awareness. This study explored whether STEM prospective secondary teachers are prepared to implement a sustainable gender-sensitive practice upon graduation. To this end, we cross-culturally validated the TEGEP (Teacher Self-Efficacy for Gender Equality practice) scale and compared STEM student teachers’ perceptions of self-efficacy by country and sex. Participants were 205 STEM (science, technology, engineering, and mathematics) secondary school student teachers (136 Greek and 69 Spanish) drawn from seven public universities (six Greek, one Spanish). Statistical analysis confirmed the structure and factor invariance of the TEGEP across country and between sexes showing evidence that gender equality self-efficacy level is only moderate and that perceived competence in gender knowledge was significantly higher in Greek than in Spanish STEM student teachers, while the latter felt more competent than the Greek in developing values and attitudes in regards to gender. The study provides a cross-validated instrument to measure gender equality self-efficacy in STEM teacher education and evaluate sustainable changes after planned interventions.
CONCEPT PAPER | doi:10.20944/preprints202011.0250.v1
Subject: Biology And Life Sciences, Biochemistry And Molecular Biology Keywords: antibiotic discovery; STEM education; biosynthetic gene cluster; molecular networking; multi-omics
Online: 6 November 2020 (16:50:46 CET)
The world faces two seemingly unrelated challenges—a shortfall in the STEM workforce and increasing antibiotic resistance among bacterial pathogens. We address these two challenges with Tiny Earth, an undergraduate research course that excites students about science and creates a pipeline for antibiotic discovery.
ARTICLE | doi:10.20944/preprints202201.0449.v1
Subject: Social Sciences, Education Keywords: STEM education; problem-solving; thinking types; space science at school; CanSat
Online: 31 January 2022 (11:11:31 CET)
Research has shown that hands-on projects promote stem education, namely, via problem-solving. CanSat, literally 'satellite in a can', is a stem educational project promoted by the European Space Agency. This paper addresses this issue by researching this STEM project, which demonstrates how problem-solving can be achieved in secondary-level students within the framework of the CanSat. We use qualitative techniques of data collection and analysis. The results showed that students use sophisticated thinking strategies to process information within this interdisciplinary project: (a) cognitive testing, cognitive organization, cognitive regulation, and monitoring, in addition to computer language and physical–mathematical calculations, are cognitive and metacognitive behavior strategies revealed in the CanSat; (b) problem-solving was suggested as a specific model, where students’ higher cognitive and metacognitive ordering processes deepen in project development; (c) computational, lateral, or divergent and convergent thinking were detected as thinking types of students associated with and mobilized in the course of problem-solving, The findings of this research have practical implications for STEM education in space science. Hands-on projects using problem-solving are an essential strategy to promote STEM education. Additionally, they are a starting point to promote meaningful learning and new thinking types.
ARTICLE | doi:10.20944/preprints201810.0372.v1
Subject: Engineering, Control And Systems Engineering Keywords: teaching robotics; science teaching; STEM; robotic tool; python; Raspberry Pi; PiCamera; vision system
Online: 17 October 2018 (05:53:30 CEST)
This paper presents the robotic platform, PiBot, that has been developed and that is aimed at improving the teaching of Robotics with vision to secondary students. Its computational core is the Raspberry Pi 3 controller board, and the greatest novelty of this prototype is the support developed for the powerful camera mounted on board, the PiCamera. An open software infrastructure written in Python language was implemented so that the student may use this camera, or even a WebCam, as the main sensor of this robotic platform. Also, higher level commands have been provided to enhance the learning outcome for beginners. In addition, a PiBot 3D printable model and the counterpart for the Gazebo simulator were also developed and fully supported. They are publicly available so that students and educational centers that do not have the physical robot or can not afford the costs of these, can nevertheless practice and learn or teach Robotics using these open platforms: DIY-PiBot and/or simulated-PiBot.
ARTICLE | doi:10.20944/preprints202012.0756.v1
Subject: Social Sciences, Education Keywords: STEM Education; Energy Efficiency; CO₂ Emissions; APEC databases; Cross-Border classes; Sustainable Development
Online: 30 December 2020 (14:37:12 CET)
Early education is critical for improving energy efficiency. The purpose of this study is to explore the feasibility of Interactive Cross-Border Classes to increase awareness of energy efficiency among middle school students. We designed and tested an Interactive Cross-Border class between Chilean and Peruvian 8th-grade classes. The classes were synchronously connected and all students answered open-ended questions on an online platform. Some of the questions were designed to check conceptual understanding while others asked for suggestions of how to develop their economies while keeping CO₂ air concentration at acceptable levels. In real-time, the teacher reviewed the students’ written answers and the concept maps that were automatically generated based on their responses. Students peer-reviewed their classmates’ suggestions. This is part of an Asia-Pacific Economic Cooperation (APEC) STEM Education project on Energy Efficiency using APEC databases. We found high levels of student engagement, where students discussed not only the cross-cutting nature of energy, but also its relation to socioeconomic development and CO₂ emissions, and the need to work together to improve energy efficiency. In conclusion, Interactive Cross-Border classes are a feasible educational alternative, with potential as a scalable public policy strategy for improving awareness of energy efficiency among the population.
ARTICLE | doi:10.20944/preprints202205.0404.v1
Subject: Physical Sciences, Nuclear And High Energy Physics Keywords: self-directed learning; graduate education; flow; David J. Rowe; open mindedness; mentoring; symmetry; narrative research; STEM
Online: 31 May 2022 (02:55:28 CEST)
The ability to self-direct a research program determines graduate degree completion. Yet, research on incompletion of graduate physics programs assume students’ present level of self-direction adequate and neglects to recognize a lack of self-directed learning as key. One theoretical mathematical physicist focused on changing this challenge of physics graduate education by promoting self-directed learning through the type research flow that has been found to bring the greatest satisfaction to researchers with respect to their insights. This he provided through his space, time, open mindedness and theoretical contributions with his students and in collaboration with his colleagues. A self-directed learner himself, David J. Rowe developed methods of mentoring for encouraging physics graduate students to recognize symmetry as valuable in identifying solutions to problems quickly—helping these students take the lead in finding insightful resolutions to complex, multidimensional, mathematical physics uncertainties. How Rowe set about supporting self-directed learning in his graduate physics education interactions will be examined with the use of narrative research to interpret the texts and conversations with the author he made available. His techniques will be presented and recommendations made regarding how Rowe’s work in this regard can be modeled to improve self-direction in STEM graduate education.
REVIEW | doi:10.20944/preprints202305.0457.v1
Subject: Biology And Life Sciences, Cell And Developmental Biology Keywords: Dental stem cells; Mesenchymal Stem Cells; Dental Pulp Stem Cells; Dental Bud Stem Cells; bone regeneration; osteogenic differentiation
Online: 8 May 2023 (05:33:58 CEST)
Teeth include mesenchymal stem cells (MSCs), which are multipotent cells that promote tooth growth and repair. Dental tissues, specifically the dental pulp and the dental bud, constitute a relevant source of multipotent stem cells, known as dental-derived stem cells (d-DSCs): dental pulp stem cells (DPSCs) and dental bud stem cells (DBSCs). Cell treatment with bone-associated factors and stimulation with small molecule compounds are, among the available methods, the ones who show excellent advantages promoting stem cell differentiation and osteogenesis. Recently, attention has been paid to studies on natural and non-natural compounds. Many fruits, vegetables and some drugs contain molecules that can enhance MSC osteogenic differentiation and therefore bone formation. The purpose of this review is to examine research work over the past 7 years that has investigated two different types of MSCs from dental tissues that are attractive targets for bone tissue engineering: DPSCs and DBSCs. We focused on articles hypothesizing the identification and study of compounds that induce proliferation and osteogenic differentiation of the two d-DSC populations, representing an interesting issue for regenerative medicine. The reconstruction of bone defects in fact is still a challenge for personalized medicine.
REVIEW | doi:10.20944/preprints202011.0268.v1
Subject: Biology And Life Sciences, Biochemistry And Molecular Biology Keywords: Keywords Exercise; osteoarthritis; osteoporosis; mesenchymal stem cells; hematopoietic stem cells; stem cell transplantation; chondroblasts; chondrocytes; cytokines.
Online: 9 November 2020 (10:00:10 CET)
Abstract: This article provides a brief review of the ontogeny of chondrocytes and the pathophysiology of osteoarthritis (OA), and details how physical exercise improves the health of osteoarthritic joints and enhances the potential of mesenchymal stem cells for successful transplantation therapy. In response to exercise chondrocytes increase their production of glycosaminoglycans, bone morphogenic proteins and antiinflammatory cytokines and decrease their production of proinflammatory cytokines and matrix degrading metalloproteinases. These changes are associated with improvements in cartilage organization and reductions in cartilage degeneration. Studies in humans indicate that exercise increases peripheral blood recruitment of bone marrow-derived mesenchymal stem cells (BM-MSC) and upregulates BM-MSC expression of osteogenic and chondrogenic genes, osteogenic micro-RNAs, and osteogenic growth factors. Rodent experiments are uniform in demonstrating that exercise enhances the osteogenic potential of BM-MSC while diminishing their adipogenic potential, and that exercise done after stem cell implantation may benefit stem cell transplant viability. Physical exercise also exerts a beneficial effect on the skeletal system by decreasing immune cell production of osteoclastogenic cytokines interleukin (IL)-1β, tumor necrosis factor (TNF)-α, and interferon (INF)-γ while increasing their production anti-osteoclastogenic cytokines IL-10 and transforming growth factor (TGF)-β. In conclusion, physical exercise done both by stem cell donors and recipients may improve the outcome of mesenchymal stem cell transplantation.
ARTICLE | doi:10.20944/preprints202106.0268.v1
Subject: Medicine And Pharmacology, Immunology And Allergy Keywords: diabetic retinopathy; mesenchymal stem cells; neural precursor cells; stem cell.
Online: 9 June 2021 (13:44:48 CEST)
This study aimed to evaluate cell therapy with human neural precursor cells (hNPCs) in diabetic retinopathy (DR) Wistar rats, induced to diabetes by intraperitoneal injection with streptozotocin. Wharton's Jelly Mesenchymal stem cells (WJ-MSCs) were isolated, expanded, and seeded onto a biopolymer substrate without growth factors to develop neurospheres to obtain the hNPCs, characterized by immunocytochemistry. The animals were divided into three groups; non-diabetic (ND) n = four; diabetic without treatment (DM) n = nine; and diabetic with cell therapy (DM + hNPCs) n = nine. After eight weeks of diabetes induction and verified DR, intravitreal injection of hNPCs (1 x 106 cel/µL) was performed in the DM + hNPCs group. Optical Coherence Tomography (OCT) and Electroretinography (ERG) evaluations were done before and after diabetes induction and after cell therapy. Eye enucleation occurred four weeks after treatment for the histopathological and immunohistochemistry analyses. In the treated group, there was the repair of the retinal structures and their arrangements. hNPCs increased the thickness of neuroretina layers, especially in the ganglion cell and photoreceptor layers. The results indicate that hNPCs reduced DR progression by a neuroprotective effect and promoted retinal repair, making them potential candidates for regeneration of the neuroretinal tissue.
REVIEW | doi:10.20944/preprints202009.0421.v1
Subject: Medicine And Pharmacology, Obstetrics And Gynaecology Keywords: Infertility; mesenchymal stem cells (MSCs); reproductive system; Stem-cell therapy
Online: 18 September 2020 (07:09:31 CEST)
Female infertility is a global medical condition that can be caused by various disorders of the reproductive system, including premature ovarian failure (POF), polycystic ovary syndrome (PCOS), endometriosis, Asherman syndrome, and preeclampsia. It affects the quality of life of both patients and couples. Mesenchymal stem cells (MSCs) have received increasing attention as a potential cell-based therapy with several advantages over other cell sources, including greater abundance, fewer ethical considerations, and high capacity for self-renewal and differentiation. Clinical researchers have examined the therapeutic use of MSCs in female infertility. In this review, we discuss recent studies on the use of MSCs in various reproductive disorders that lead to infertility. We also describe the role of microRNAs (miRNAs) and exosomal miRNAs in controlling MSC gene expression and driving MSC therapeutic outcomes. The clinical application of MSCs holds great promise for the treatment of infertility or ovarian insufficiency and to improve reproductive health for a significant number of women worldwide.
ARTICLE | doi:10.20944/preprints202007.0484.v1
Subject: Medicine And Pharmacology, Pathology And Pathobiology Keywords: Gastric cancer; Submucosal invasion; Intestinal stem cell; Cancer stem cell; Prognosis
Online: 21 July 2020 (12:34:02 CEST)
Submucosal invasion is a critical step in gastric cancer (GC) progression, which greatly enhances metastasis risk. Cancer stem cells are responsible for invasion, metastasis, and tumor growth. To identify stem cell-related markers associated with submucosal invasion in GCs, we investigated the expression of candidate cancer stem cell (CSC) markers (CD133, CD44, and ALDH1A) and intestinal stem cell (ISC) markers (EPHB2, OLFM4, and LGR5) in early GCs with submucosal invasion. Remarkably, expression of all ISC markers and CD133 was frequently confined to the basal area of the lamina propria (basal pattern) in mucosal cancer. The proportion of stem cell marker-positive cells substantially increased during submucosal invasion. Given that ISC markers are restricted to the crypt base of the normal intestinal mucosa, these findings suggest that many early GCs may retain hierarchical characteristics. CD44 expression showed a focal pattern, ALDH1A was predominantly expressed diffusely, and there was no expansion of CD44 or ALDH1A expression in the submucosal cancer cells. RSPO2 from muscularis mucosa seem to be partly responsible for the increased expression of ISC markers in GC cells at the basal areas. We also found that ISC markers were correlated with CDX2 expression in GCs, indicating that ISC markers are involved in the intestinal differentiation in GCs. Interestingly, ISC markers (EPHB2 and OLFM4) and CD133 showed a positive impact on clinical outcomes. In particular, the prognostic value of EPHB2 was significant for intestinal-type GCs in a multivariate analysis. In summary, ISC markers and CD133 showed a basal distribution pattern along with enhanced expression in submucosal invading cells in early GCs. EPHB2 was an independent prognostic marker in intestinal-type GCs.
REVIEW | doi:10.20944/preprints202004.0242.v1
Subject: Biology And Life Sciences, Cell And Developmental Biology Keywords: extracellular vesicles; stem cells; induced pluripotent stem cells (iPSCs); regenerative medicine
Online: 15 April 2020 (10:08:44 CEST)
Regenerative medicine aims to repair damaged or missing cells, tissues or organs for the treatment of various diseases, poorly managed with conventional drugs and medical procedures. To date there are different approaches to obtain these results. Multimodal regenerative methods include transplant of healthy organs, tissues, or cells, body stimulation to activate a self healing response in damaged tissues, as well as the combined use of cells and bio-degradable scaffold to obtain functional tissues. Certainly, stem cells and derived products are promising tools in regenerative medicine due to their ability to induce de novo tissue formation and/or promote tissue and organ repair and regeneration. Currently, several studies have shown that the beneficial stem cell effects in damaged tissue restore are not depending on their engraftment and differentiation on the injury site, but rather to their paracrine activity. It is now well known that paracrine action of stem cells is due to their ability to release Extracellular Vesicles (EVs). EVs play a fundamental role in cell-to cell communication and are directly involved in tissue regeneration. In the present review, we tried to summarize the molecular mechanisms trough which EVs carry out their therapeutic action and their possible application for the treatment of several diseases.
REVIEW | doi:10.20944/preprints201909.0079.v1
Subject: Medicine And Pharmacology, Pathology And Pathobiology Keywords: Thromboangiitis Obliterans; inflammation; angiogenesis; immunomodulation; pluripotent stem cell; mesenchymal stem cell
Online: 7 September 2019 (00:31:05 CEST)
Buerger's disease or Thromboangiitis Obliterans (TAO) is a nonatherosclerotic segmental vascular disease which affects small and medium arteries and veins in the upper and lower extremities. Based on pathological findings, TAO can be considered as a distinct form of vasculitis that is most prevalent in young male smokers. There is no definitive cure for this disease as therapeutic modalities are limited in number and efficacy. Surgical bypass has limited utility and 24% of patients will ultimately require amputation. Recently, studies have shown that therapeutic angiogenesis and immunomodulatory approaches through the delivery of cells to target tissues are potential options for ischemic lesion treatment. In this review, we summarize the current knowledge of TAO treatment and provide an overview of stem cell-based treatment modalities.
REVIEW | doi:10.20944/preprints202010.0623.v1
Subject: Medicine And Pharmacology, Immunology And Allergy Keywords: Glioblastoma; Neural Stem Cells; Mesenchymal Stem Cells; Stem Cell Therapy; Enzyme/Prodrug Therapy; Oncolytic Virotherapy; Nanoparticles; TRAIL; Cytokine Therapy
Online: 29 October 2020 (15:51:04 CET)
The potential of Neural Stem Cells (NSCs) to provide therapeutic benefit for a variety of neurological disorders, including brain malignancies, has been long recognized and has inspired many scientists to design, test and successfully demonstrate that NSCs are efficient and effective therapeutic agents. Glioblastoma, the deadliest form of primary brain tumor, despite extensive and sustained efforts to find better therapies, remains a disease without cure, with a median survival after diagnosis of less than two years. Treatment resistance in glioblastoma is in large part attributed to limitations in the delivery and distribution of therapeutic agents administered either systemically or directly into the tumor due to the highly invasive nature of this cancer and its abnormal intratumoral vasculature. Stem Cells (SCs) have an innate tumor-tropic migratory behavior, can be modified to deliver a variety of therapeutic agents and efficiently distribute their cargo into brain tumors, pursuing invading streams of tumor cells, deep into the brain parenchyma. Over the last twenty years, numerous preclinical trials have demonstrated the feasibility and efficacy of SCs as antiglioma agents, leading to the development of trials to test these therapies in the clinic. In this review we present and analyze these studies and discuss mechanisms underlying their beneficial effect, highlighting experimental progress, limitations and the emergence of promising new therapeutic avenues. We hope to increase awareness of the advantages of using SCs for the treatment of glioblastoma and inspire further studies that will lead to accelerated implementation of effective therapies.
REVIEW | doi:10.20944/preprints201809.0434.v1
Subject: Medicine And Pharmacology, Oncology And Oncogenics Keywords: colorectal cancer, cancer stem cells, mesenchymal stromal cells, stem cell markers, chemoresistance, treatment personalization, biomarkers, cancer stem cell markers
Online: 21 September 2018 (10:07:54 CEST)
BACKGROUND: Treatment failure in primary as well as metastatic cancer patients, caused by chemo and radio resistance, has truncated the research for the applicability of personalized medicine. The use of stem cells and cancer stem cells in such a treatment approach will be reviewed in this study. RESULTS: CRC stem cells prove to be a promising asset for CRC treatment optimization both by serving as biomarkers for the current therapy modalities by means of treatment personalization and patient/tumor stratification, as well as in the development of targeted therapies, selective for the stem cell population. Similar conclusions are drawn, regarding mesenchymal stromal cells and their effect in CRC therapy; while resident stromal cells of tumor microenvironment seem to promote the tumorigenic and metastatic processes in addition to conferring to the chemo- and radio resistance, under certain conditions they are able to improve the treatment outcome of CRC chemotherapy, e.g. by targeted enzyme/prodrug treatment of CRC cells. CONCLUSION: This review, truncates the dynamic potential of cancer stem cells and other stem cell types in CRC treatment personalization as well as, in the improvement of current treatment approaches opting to a higher therapeutic rate, improved prognosis, survival and quality of life for CRC patients.
ARTICLE | doi:10.20944/preprints201701.0088.v2
Subject: Biology And Life Sciences, Endocrinology And Metabolism Keywords: Adipose derived stem cell (ASC); Regenerative medicine; embryonic stem cell marker network
Online: 20 January 2017 (04:56:06 CET)
The stromal vascular cell fraction (SVF) of visceral and subcutaneous adipose tissue (VAT and SAT) has increasingly come into focus in stem cell research, since these compartments represent a rich source of multipotent adipose-derived stem cells (ASCs). ASCs exhibit a self- renewal potential and differentiation capacity. Our aim was to study the different expression of embryonic stem cell markers NANOG, SOX2 and OCT3/4 and to evaluate if there exists a hierarchal role in this network in ASCs derived from both SAT and VAT. ASCs were isolated from SAT and VAT biopsies of 72 consenting patients (23 men, 47 women; age 45 ± 10; BMI between 25 and 30 range) undergoing elective open-abdominal surgery. Sphere-forming capability was evaluated by plating cells in low adhesion plastic. Stem cell markers CD90 and CD105 were analyzed by flow cytometry and stem cell transcription factors NANOG, SOX2 and OCT3/4 were detected by immunoblotting and Real-Time PCR. NANOG, SOX2 and OCT3/4 interplay was explored by gene silencing. ASCs from VAT and SAT confirmed their mesenchymal stem cell (MSC) phenotype expressing the specific MSC markers CD90, CD105, NANOG, SOX2 and OCT3/4. NANOG silencing induced a significant OCT 3/4 (70% ± 0.05) and SOX2 (75% ± 0.03) down-regulation whereas SOX2 silencing did not affect NANOG gene expression. Adipose tissue is an important source of MSC, and siRNA experiments endorse a hierarchical role of NANOG in the complex transcription network that regulates pluripotency and plasticity.
ARTICLE | doi:10.20944/preprints202205.0089.v1
Subject: Biology And Life Sciences, Cell And Developmental Biology Keywords: placenta-derived stem cells; placenta; stem cells; proteostasis; heat-shock; chaperones; HSPA1B; HSPA1A
Online: 7 May 2022 (03:37:17 CEST)
Placenta-derived stem cells (PDSCs) offer the advantages of possessing mesenchymal and embryonic traits, broad differentiation potential, large-scale availability, and no ethical constraints in their utilization in therapeutic applications. Elevated protein synthesis and consequently enhanced protein maintenance networks become necessary both due to the requirement to maintain stemness and respond to different stresses. This study aimed to identify the primary determinants of proteotoxic stress response in PDSCs. We generated heat-induced dose-responsive proteotoxic stress models of three stem cell types DBMSCs, DPMSCs, and pMSCs, and measured stress induction through biochemical and cell proliferation assays. RT-PCR array analysis of 84 genes involved in protein folding and protein quality control led to the identification of Hsp70 isoforms HSPA1A and HSPA1B as the prominent ones among 17 significantly expressed genes and with further analysis at the protein level through western blotting. A 24-hours’ time series analysis of stress-response allowed a detailed kinetic analysis of HSPA1A and HSPA1B gene and protein expression. More prominent differences between the two Hsp70 isoforms were detected at the translational level eluding to a potential higher requirement for HSPA1B during proteotoxic stress in PDSCs. To conclude, consideration should be given to the manipulation of definitely characterized chaperones at their expression or functional levels when utilizing PDSCs in therapeutic and regenerative applications.
REVIEW | doi:10.20944/preprints201808.0149.v1
Subject: Medicine And Pharmacology, Cardiac And Cardiovascular Systems Keywords: atherosclerosis, mesenchymal stem cells, inflammation
Online: 7 August 2018 (23:22:20 CEST)
Atherosclerosis is a chronic inflammatory disease which results in thickening of the vessel wall and narrowing of the lumen. It is a leading cause of death worldwide. Preventive treatment is taken into prioritized consideration since currently no effective approaches to cure atherosclerosis are available. These treatments mainly focus on lowering blood cholesterol levels, especially LDL-C, by statins. Even so, lowering lipid levels is not sufficient to reduce the risk of cardiovascular events in all patients. Recently, atherosclerosis has increasingly been recognized as a chronic inflammatory disease involving the immune system, initiating new therapeutic approaches which could alleviate or prevent atherosclerosis by modulating inflammation. Mesenchymal stem cells (MSCs) have emerged as a promising option to relieve inflammation and balance immune responses in inflammatory diseases. Several studies including our group also reported that MSCs may be a new therapeutic option for atherosclerosis. This review summarizes the updated state of our knowledge in the administration of MSCs to alleviate atherosclerosis and discusses some of the key unresolved challenges that need to be solved in future studies.
BRIEF REPORT | doi:10.20944/preprints201707.0079.v1
Subject: Medicine And Pharmacology, Pharmacology And Toxicology Keywords: alcohol consumption; tobacco smoking; carcinogenesis; addiction; stem cells; stem cell division theory of cancer
Online: 27 July 2017 (12:34:00 CEST)
Almost 6% of cancers worldwide are attributable to alcohol consumption. Approximately half of them occur in tissues highly exposed to ethanol, such as the oral cavity, pharynx, upper larynx and esophagus. However, since ethanol is not mutagenic and the carcinogenic metabolite of ethanol (acetaldehyde) is mainly produced in the liver, it is unclear why alcohol consumption preferentially causes a local carcinogenic effect. We recently hypothesized that the cytotoxic activity of ethanol could explain the high risk of these cancers in alcohol users. Here we report that short-term exposures (2-3 seconds) to ethanol concentrations between 10% and 15% start to cause a marked cytotoxic effect on human epithelial keratinocytes in a concentration-dependent manner. After discussing new evidence that cancer is the end-result of the accumulation of cell divisions in stem cells, we explain why regular alcohol consumption imposes a high risk of cancer on these tissues. Briefly, the cytotoxicity of ethanol reduces the lifespan of the cells lining these tissues. The stem cells located in deeper layers need to divide more often than usual to renew the damaged epithelia. The accumulation of cell divisions in stem cells leads to the accumulation of cancer-promoting errors (e.g., mutations arising during DNA replication) that increase their risk of malignant transformation. Cell division also exposes the DNA of the stem cells to the genotoxic activity of acetaldehyde and tobacco carcinogens. We propose that choosing alcoholic beverages containing non-cytotoxic concentrations of ethanol, or diluting ethanol to non-cytotoxic concentrations, is a simple way to reduce the risk of cancer of the oral cavity, pharynx, larynx and esophagus in alcohol users. This preventive strategy may also abolish the known synergistic effect of alcohol drinking and tobacco smoking on the risk of these cancers.
REVIEW | doi:10.20944/preprints201707.0074.v1
Subject: Medicine And Pharmacology, Oncology And Oncogenics Keywords: cancer etiology; carcinogenesis; cancer prevention; stem cells; cancer stem cells; stem cell environment; cells of origin in cancer; somatic mutation theory of cancer
Online: 26 July 2017 (08:42:41 CEST)
All cancer registries constantly show striking differences in cancer incidence by age and among tissues. For example, lung cancer is diagnosed hundreds of times more often at age 70 than at age 20, and this cancer in nonsmokers occurs thousands of times more frequently than heart cancer in smokers. An analysis of these differences using basic concepts in cell biology indicates that cancer is the end-result of the accumulation of cell divisions in stem cells. In other words, the main determinant of carcinogenesis is the number of cell divisions that the DNA of a stem cell has accumulated in any type of cell from the zygote. Cell division, process by which a cell copies and separates its cellular components to finally split into two cells, is necessary to produce the large number of cells required for living. However, cell division can lead to a variety of cancer-promoting errors, such as mutations occurring during DNA replication, chromosome aberrations arising during mitosis, errors in the distribution of cell-fate determinants between the daughter cells, and failures to restore physical interactions with other tissue components. Some of these errors are spontaneous, others are promoted by endogenous DNA damage occurring during quiescence, and others are influenced by pathological and environmental factors. The cell divisions required for carcinogenesis are primarily caused by multiple local and systemic physiological signals rather than by errors in the DNA of the cells. As carcinogenesis progresses, the accumulation of DNA errors promotes cell division and eventually triggers cell division under permissive extracellular environments. The accumulation of cell divisions in stem cells drives not only the accumulation of the DNA alterations required for carcinogenesis, but also the formation and growth of the abnormal cell populations that characterize the disease. This model of carcinogenesis provides a new framework for understanding the disease and has important implications for cancer prevention and therapy.
ARTICLE | doi:10.20944/preprints201910.0229.v1
Subject: Medicine And Pharmacology, Oncology And Oncogenics Keywords: malignant melanoma; head and neck cancer; cancer stem cell; melanoma metastasis; induced pluripotent stem cell
Online: 19 October 2019 (17:15:36 CEST)
Cancer stem cells (CSCs) have been identified in many cancer types. This study identified and characterized CSCs in head and neck metastatic malignant melanoma (HNmMM) to regional lymph nodes using induced pluripotent stem cell (iPSC) markers. Immunohistochemical (IHC) staining performed on 20 HNmMM tissue samples demonstrated expression of iPSC markers OCT4, SOX2, KLF4 and c-MYC in all samples while NANOG was expressed at low levels in two samples. Immunofluorescence (IF) staining demonstrated an OCT4+/SOX2+/KLF4+/c-MYC+ CSC subpopulation within the tumor nests (TNs) and another within the peritumoral stroma (PTS) of HNmMM tissues. IF also showed expression of NANOG by some OCT4+/SOX2+/KLF4+/c-MYC+ cells within the TNs in an HNmMM tissue sample that expressed NANOG on IHC staining. In situ hybridization (n=6) and reverse-transcription quantitative polymerase chain reaction (n=5) on the HNmMM samples confirmed expression of all five iPSC markers. Western blotting of four primary cell lines derived from four of the 20 HNmMM tissue samples showed expression of SOX2, KLF4, and c-MYC but not OCT4 and NANOG, and three of these cell lines formed tumorspheres in vitro. We demonstrate the presence of two putative CSC subpopulations within HNmMM, which may be a novel therapeutic target in the treatment of this aggressive cancer.
ARTICLE | doi:10.20944/preprints202007.0545.v1
Subject: Social Sciences, Education Keywords: gender; academic; STEM; leadership; barriers; assistance
Online: 23 July 2020 (10:06:20 CEST)
Women in science, technology, engineering, and mathematics (STEM) fields are under-represented, and women are also less likely than men to be in leadership positions generally. Little is known about the intersection of these areas: women in leadership in STEM. To determine what sort of barriers and assistance female STEM leaders have encountered, a survey was developed asking women who are in academic leadership positions in STEM about their experiences. The main barriers were similar in the STEM area and in leadership: balancing work/home life, devaluing of achievements, and imposter syndrome. The main two types of assistance in both STEM and leadership were support from spouse/partner, and encouragement from peers. The main barriers women encounter are cultural and will take time to overcome. The main assistance women have had comes from people, not training or institutional structures.
ARTICLE | doi:10.20944/preprints201911.0120.v1
Subject: Social Sciences, Education Keywords: gender; leadership; science; STEM; department chair
Online: 11 November 2019 (04:53:34 CET)
A considerable body of research exists on women in leadership and likewise on women in STEM (science, technology, engineering, mathematics) fields. However, the intersection of the two is terra incognita: women in leadership in STEM. At the most fundamental level, we don’t even have a solid idea of how many women hold leadership positions in STEM. This study determined the proportion of women in leadership positions in several academic STEM areas via a sampling of institutions across the United States and other countries. In every area studied, women held fewer leadership positions than the proportion of female PhDs in those fields. The proportion of women in non-STEM specific top academic leadership roles was also examined to see what proportion of those individuals leading academic institutions might have background in a STEM discipline and how that compares to men in the same positions. This study opens the door to exploring the experiences of women who lead in STEM, which is likely to promote women’s participation in these fields.
REVIEW | doi:10.20944/preprints202303.0552.v1
Subject: Medicine And Pharmacology, Neuroscience And Neurology Keywords: Mucopolysaccharidoses; Disease Modeling; in vitro models; induced Pluripotent Stem Cells (iPSCs); Dental Pulp Stem Cells (DPSC)
Online: 31 March 2023 (14:43:34 CEST)
Despite extensive research, the links between the accumulation of glycosaminoglycans (GAGs) and the clinical features seen in patients suffering from various forms of Mucopolysaccharidoses (MPSs) have yet to be further elucidated. This is particularly true for the neuropathology of these disorders, even though the neurological symptoms are currently incurable, even in the cases where a dis-ease-specific therapeutic approach does exist. One of the best ways to get insights on the molecular mechanisms driving that pathogenesis is the analysis of patient-derived cells. Yet, not every pa-tient-derived cell holds potential to recapitulate relevant disease features. For the neurodegenerative forms of these diseases in particular, it is challenging to grow neuronal cultures that accurately represent them because of the obvious inability to access live neurons. This scenario changed sig-nificantly since Yamanaka et al. published their protocol for induction of pluripotent stem cells (SC) from adult human fibroblasts. From then on, a series of differentiation protocols to generate neurons from induced pluripotent stem cells (iPSC) was developed and extensively used for disease mod-eling. Currently, human iPSC and iPSC-derived cell models have been generated for several MPS and numerous lessons were learnt from their analysis. Here we review most of those studies, not only listing the currently available MPS iPSC lines and their derived models, but also summarizing how they were generated and the major information different groups have gathered from their analysis. Finally, and taking into account that iPSC generation is a laborious/expensive protocol that holds significant limitations, we also comment on a tempting alternative to establish MPS pa-tient-derived neuronal cells in a much more expedite way by taking advantage of the existence of a population of multipotent SC in human dental pulp, to establish mixed neuronal and glial cultures.
ARTICLE | doi:10.20944/preprints202208.0070.v1
Subject: Medicine And Pharmacology, Cardiac And Cardiovascular Systems Keywords: adipocyte-derived mesenchymal stem cells; cardiomyocyte-like cells; platelet rich fibrin; growth factor; stem cell therapy
Online: 3 August 2022 (03:31:51 CEST)
Background: There is several challenges to solve irreversible loss of cardiomyocytes due to myocardial infarction. Cell therapy is believed as an ideal treatment for cardiac regeneration in the infarct area. Obtaining adipose-derived stem cells increases seems to be promising, however it is limited by the capacity to differentiate. Stimulation by injectable platelet-rich fibrin appears to have the beneficial effects to accelerate cardiomyocyte-like cells differentiation. Objective: To analyse the benefit of injectable platelet-rich fibrin to accelerate differentiation of adipose-derived mesenchymal stem cells into cardiomyocyte-like cells. Methods: This study is a true experimental randomized post-test design study. Adipose-derived mesenchymal stem cells were isolated from adipose tissues and cultured until 4 passages. The characteristics of adipose-derived mesenchymal stem cells were measured by the expression of CD 34-, CD 45-, and CD 105+ using flowcytometry. The samples were divided into 3 groups, i.e. negative control (α-MEM), positive control (differentiation medium) and treatment group (platelet-rich fibrin). The assessment of GATA-4 marker expression was conducted using flowcytometry on the fifth day and troponin was conducted using immunocytochemistry on the tenth day to determine the differentiation to cardiomyocyte. Data analysis was conducted using T-test and One-Way ANOVA on normally distributed data determined through Shapiro-Wilk test. Results: Flowcytometry on GATA-4 expression revealed significant difference on addition of platelet-rich fibrin compared with negative and positive controls (68.20 ± 6.82 vs 58.15 ± 1.23; p<0.05; 68.20 ± 6.82 vs 52.96 ± 2.02; p<0.05). This was supported by the results of immunocytochemistry on troponin expression which revealed significant difference between platelet-rich fibrin group compared with negative and positive controls (50.66 ± 7.2 vs 10.73 ± 2.39; p<0.05; 50.66 ± 7.2 vs 26.00 ± 0.4; p<0.05). Conclusion: Injectable platelet-rich fibrin has beneficial effect to accelerate differentiation of adipose-derived mesenchymal stem cells into cardiomyocyte-like cells.
ARTICLE | doi:10.20944/preprints202104.0003.v1
Subject: Environmental And Earth Sciences, Atmospheric Science And Meteorology Keywords: under-canopy surveys; UAV laser scanning; tree height; stem curve; stem volume; field reference; forest plot
Online: 1 April 2021 (09:53:15 CEST)
Automation of forest field reference data collection has been an intensive research objective for laser scanning scientists ever since the invention of terrestrial laser scanning more than two decades ago. Recently, it has been proposed that such automated data collection providing both the tree heights and stem curves would require a combination of above-canopy UAV point clouds and terrestrial point clouds. In this study, we demonstrate that an under-canopy UAV laser scanning system utilizing a rotating laser scanner can alone provide accurate estimates of the canopy height and the stem volume for the majority of the trees in a boreal forest. To this end, we mounted a rotating laser scanner based on a Velodyne VLP-16 sensor onboard a manually piloted UAV. The UAV was commanded with the help of a live video feed from the onboard camera of the UAV. Since the system was based on a rotating laser scanner providing varying view angles, all important elements such as treetops, branches, trunks, and ground could be recorded with laser hits. In an experiment including two different forest structures, namely sparse and obstructed canopy, we showed that our system can measure the heights of individual trees with a bias of -20 cm and a standard error of 40 cm in the sparse forest and with a bias of -65 cm and a standard error of 1 m in the obstructed forest. The accuracy of the obtained tree height estimates was equivalent to airborne above-canopy UAV surveys conducted in similar forest conditions. The higher underestimation and higher inaccuracy in the obstructed site can be attributed to three trees with a height exceeding 25 m and the applied laser scanning system VLP-16 that had a limited height measurement capacity when it comes to trees taller than 25 m. Additionally, we used our system to estimate the stem volumes of individual trees with a standard error at the level of 10%. This level of error is equivalent to the error obtained when merging above-canopy UAV laser scanner data with terrestrial point cloud data. Future research is needed for testing new sensors, for implementing autonomous operation inside canopies through collision avoidance and navigation through canopies, and for developing robust methods that work also with more complex forest structure. The results show that we do not necessarily need a combination of terrestrial point clouds and point clouds collected using above-canopy UAV systems in order to accurately estimate the heights and the volumes of individual trees.
ARTICLE | doi:10.20944/preprints202005.0047.v1
Subject: Biology And Life Sciences, Biochemistry And Molecular Biology Keywords: tumor microenvironment; biomarkers; solid cancers; computational biology; cancer stem cells; anti-cancer stem cell therapy; chemotherapy
Online: 4 May 2020 (10:00:51 CEST)
Solid tumors display complex biology and most therapies including chemotherapy cannot prevent therapy resistance and relapse. Most therapeutics target cancer cells, but recent data suggest the presence of cancer stem cells as cells with self-renewal and tumorigenic abilities. Cancer stem cell markers have been suggested to have prognostic value and can be targeted during cancer treatment and in resistant disease. CSCs have been postulated to play significant contextual roles in tumor initiation, progression, therapy resistance and metastasis. CSCs have thus been targeted by new generation cancer drugs. The transcriptional expression of several CSC markers in different cancers was evaluated by searching publicly available The Cancer Genome Atlas (TCGA) and Gene Expression Profiling Interactive Analysis (GEPIA) databases. We report here new findings on expression and prognostic significance of CSC markers in several cancers by examining the expression of CSCs markers in tumor tissues versus the adjacent normal tissues. We found that CSC markers were mostly highly expressed various tumors such as colon, lung, pancreatic and esophageal cancers. No CSC marker is expressed in the same pattern in all cancers and individual CSC marker expression was not linked to patient survival. This analysis calls for continued research on CSCs and clinical evaluation of the CSC markers in relation to prognosis of cancers in large population samples. Novel cancer drugs ought to target CSCs, cancer cells and tumor microenvironment variations.
ARTICLE | doi:10.20944/preprints201911.0162.v1
Subject: Biology And Life Sciences, Cell And Developmental Biology Keywords: human pluripotent stem cells; human stem cell-derived hepatocytes; in vitro; metabolic diseases; transcriptomics; maturation; characterization
Online: 14 November 2019 (11:24:24 CET)
There is a strong anticipated future for human pluripotent stem cell-derived hepatocytes (hiPS-HEP), but so far their use has been limited due to insufficient functionality. We investigated the potential of hiPS-HEP as an in vitro model for metabolic diseases by combining transcriptomics with multiple functional assays. The transcriptomics analysis revealed that 86% of the genes were expressed at similar levels in hiPS-HEP as in human primary hepatocytes (hphep). Adult characteristics of the hiPS-HEP were confirmed by the presence of important hepatocyte features, e.g. Albumin secretion and expression of major drug metabolizing genes. Normal energy metabolism is crucial for modeling metabolic diseases, and both transcriptomics data and functional assays showed that hiPS-HEP were similar to hphep regarding uptake of glucose, LDL and fatty acids. Importantly, the inflammatory state of the hiPS-HEP was low under standard conditions, but in response to lipid accumulation and ER stress the inflammation marker TNFα was upregulated. Furthermore, hiPS-HEP could be co-cultured with primary hepatic stellate cells both in 2D and in 3D spheroids, paving the way for using these co-cultures for modeling NASH. Taken together, hiPS-HEP have the potential to serve as an in vitro model for metabolic diseases. Furthermore, differently expressed genes identified in this study can serve as targets for future improvements of the hiPS-HEP.
Subject: Medicine And Pharmacology, Oncology And Oncogenics Keywords: alcohol; cancer; ethanol; tobacco; carcinogenesis; oral cavity; pharynx; esophagus; stem cells; stem cell division theory of cancer
Online: 16 August 2016 (09:45:33 CEST)
Epidemiological data indicate that 5.8% of cancer deaths world-wide are attributable to alcohol consumption. The risk of cancer is higher in tissues in closest contact on ingestion of alcohol, such as the oral cavity, pharynx and esophagus. The risk of these cancers is increased even in people who have only one alcoholic drink per day. However, since ethanol is not mutagenic and the carcinogenic metabolite of ethanol (acetaldehyde) is mostly produced in the liver, it is not clear why alcohol use preferentially exerts a local carcinogenic effect. It is well known that ethanol causes cell death at the concentrations present in alcoholic beverages; however, this effect has been overlooked probably because dead cells cannot give rise to cancer. Here I discuss that the cytotoxic effect of ethanol on the cells lining the oral cavity, pharynx and esophagus activates the division of the stem cells located in deeper layers of the mucosa to replace the dead cells. Every time stem cells divide, they become exposed to unavoidable errors associated with cell division (e.g., mutations arising during DNA replication and chromosomal alterations occurring during mitosis) and also become highly vulnerable to the genotoxic activity of endogenous and exogenous DNA-damaging agents (e.g., reactive oxygen species, acetaldehyde and tobacco carcinogens). Alcohol consumption probably increases the risk of developing cancer of the oral cavity, pharynx and esophagus by promoting the accumulation of cell divisions in the stem cells that maintain these tissues in homeostasis. Because the cytotoxic activity of ethanol is concentration-dependent, the risk of these cancers will not only increase with increasing amounts of ethanol, but also with increasing concentrations; an ounce of whisky is probably more carcinogenic when taken undiluted than when taken mixed with non-alcoholic beverages. The local cytotoxic effect of ethanol can also explain the known synergistic effect of alcohol and tobacco use on the risk of these cancers. Understanding the mechanisms of carcinogenicity of alcohol is important to reinforce the epidemiological evidence and to raise public awareness of the strong link between alcohol consumption and cancer.
REVIEW | doi:10.20944/preprints202305.0459.v1
Subject: Medicine And Pharmacology, Cardiac And Cardiovascular Systems Keywords: PAD; CLI; Stem cells therapy; endovascular device
Online: 8 May 2023 (05:38:31 CEST)
Atherosclerosis is a dynamic, chronic and progressive process that involves the vascular bed (coronary and peripheral). Risk factors are associated with the progression rate and with the evolution of atherosclerosis. There are traditional risk factors and non-traditional risk factors, all of them lead to endothelial dysfunction. Endothelial dysfunction plays a key factor in atherosclerosis. It accompanies hypercholesterolemia, diabetes, hypertension, cigarette smoking – leading to the development of atherosclerosis. Endothelial dysfunction can be reversed by treating hyperlipidemia and other damaging processes, and the mechanism is believed to be associated with an increase in vascular endogenous NO. PAD is a devastating disease, leading to leg pain and amputation. Until now the optional treatments don’t cure or prevent the uneventful outcome, but may slow the downhill progression. We summarize the updated knowledge of the management of PAD and suggest a novel approach to treat patients with PAD, using stem cells technology and a special novel endovascular device that will deliver the cells continuously on the long run and may halt the progression of atherosclerosis or even cure PAD.
ARTICLE | doi:10.20944/preprints202208.0122.v1
Subject: Biology And Life Sciences, Cell And Developmental Biology Keywords: neurogenic potential; neurites; SCAPs; sphere; stem cells
Online: 5 August 2022 (09:59:07 CEST)
Abstract: Cell-based neural regeneration is challenging due to the difficulty in obtaining sufficient neural stem cells with clinical applicability. SCAPs originating from embryonic neural crest with high neurogenic potential could be a promising cell source for neural regeneration. This study aimed to investigate whether the formation of 3D spheres can promote SCAPs neurogenic potential. Material and methods: 3D SCAPs spheres were first generated in 256-well agarose microtissue mold. The spheres and single cells were individually cultured on collagen I coated μ-Slide for 4 and 7 days. Cell morphological changes, neural marker expression, and neurite outgrowth were evaluated under a confocal microscope. Secretion of BDNF and NGF-β was measured by ELISA kits. Results: Pronounced morphological changes were noticed in a time-dependent manner. The migrating cells’ morphology changed from fibroblast-like cells to neuron-like cells. Compared to the 2D culture, neurite length, number, and the expression of neural markers, including Nestin, β-tubulin III, NeuN, and MAP-2 were significantly increased in the 3D spheres, while the secretion of BDNF and NGF-β was markedly downregulated at day 7. Conclusion: The formation of 3D spheres enhanced the neurogenic potential of SCAPs, suggesting the advantage of using the 3D spheres of SCAPs for the treatment of neural diseases.
REVIEW | doi:10.20944/preprints202203.0003.v1
Subject: Biology And Life Sciences, Biology And Biotechnology Keywords: cattle; in vitro technologies; stem cells; IVF
Online: 1 March 2022 (04:24:34 CET)
Early development in mammals is characterized by the ability of each cell to produce a complete organism plus the extraembryonic, or placental, cells, defined as pluripotency. During subsequent development, pluripotency is lost, and cells begin to differentiate to a particular cell fate. This review summarizes the current knowledge of pluripotency features of bovine embryos cultured in vitro, focusing on the core of pluripotency genes (OCT4, NANOG, SOX2, and CDX2), and main chemical strategies for controlling pluripotent networks during early development. Finally, we will discuss the applicability of manipulating pluripotency during morula to blastocyst transition in cattle species.
HYPOTHESIS | doi:10.20944/preprints202201.0097.v1
Subject: Biology And Life Sciences, Animal Science, Veterinary Science And Zoology Keywords: Stem cells; proliferation; tumour; benign tumour; cancer
Online: 10 January 2022 (11:05:50 CET)
Our tissues usually have just the right number of cells to optimally fulfil their function. Not enough cells within a tissue can lead to dysfunction, while too many cells result in a tumour. Yet, how this homeostatic balance is maintained remains poorly defined. Most differentiated cells within tissues have a finite lifespan and need to be replaced at a corresponding pace to maintain tissue homeostasis. These new differentiated cells are generated by proliferation of the stem/progenitor cells that serve the tissue. Work in simple invertebrates clearly suggests stem cells respond to at least two types of signals: niche signaling and growth factors. Niche signals promote the undifferentiated state by preventing differentiation, and thus allow for stem cell self-renewal. Growth factor sources comprise a systemic input reflecting the animal’s nutritional status, and a localized, homeostatic feedback from the tissue that the stem cells serve. That homeostatic signal couples stem cell proliferation rates to the tissue’s need for new differentiated cells. Evidence from simple organisms suggests two types of benign tumours can arise from deregulation of either niche or homeostatic signaling. Namely, constitutive niche signaling promotes the formation of undifferentiated “stem cell” tumours, while defective homeostatic signaling leads to the formation of differentiated tumours. We propose that these principles may be conserved and underlie benign tumour formation in humans, while benign tumours can evolve into cancer.
BRIEF REPORT | doi:10.20944/preprints202105.0298.v1
Subject: Biology And Life Sciences, Plant Sciences Keywords: cryptochrome; phytochrome; Arabidopsis; mutants; stem elongation; flowering
Online: 13 May 2021 (13:29:21 CEST)
To clarify whether cryptochrome contributes to stem elongation and flowering promoted by blue lights associated with low phytochrome activity, wild-type Arabidopsis was compared with its cryptochrome-deficient mutants and cryptochrome-overexpressing transgenic plants. Results indicated that the promotion effects were mainly related to low CRY1 activity, despite partial involvement of high-activity CRY2.
ARTICLE | doi:10.20944/preprints202008.0637.v1
Subject: Medicine And Pharmacology, Oncology And Oncogenics Keywords: glioblastoma; neural stem cells; replicative senescence; metastasis
Online: 28 August 2020 (11:33:23 CEST)
Due to its aggressive and invasive nature glioblastoma (GBM), the most common and aggressive primary brain tumour in adults, remains almost invariably lethal. Significant advances in the last several years have elucidated much of the molecular and genetic complexities of GBM. However, GBM exhibits a vast genetic variation and a wide diversity of phenotypes that has complicated the development of effective therapeutic strategies. This complex pathogenesis makes it necessary the development of experimental models that could be used to further understand the disease, and also to provide a more realistic testing ground for potential therapies. In this report, we describe the process of transformation of primary mouse embryo astrocytes into immortalized cultures with neural stem cell characteristics, that are able to generate of GBM when injected in the brain of C57BL/6 mice, or heterotopic tumours when injected iv. Overall, our results show that oncogenic transformation is a fate for NSC if cultured for long periods in vitro. In addition, since no additional hit is necessary to induce the oncogenic transformation, our model may be used to investigate the pathogenesis of gliomagenesis and to test the effectiveness of different drugs throughout the natural history of GBM.
Subject: Medicine And Pharmacology, Transplantation Keywords: ischemia-reperfusion injury; mesenchymal stem cells; treatment
Online: 11 June 2019 (04:28:04 CEST)
The shortage of donor organs is a major global concern. Organ failure requires the transplantation of functional organs. Organ donors are preserved in warm or cold ischemia. Ischemia and reperfusion damage the organs, due to the lack of oxygen during the ischemia step and the oxidative stress during the reperfusion step. Different methodologies were developed to prevent or diminish the level of injuries. Preservation solutions were first developed, followed by the addition of chemical compounds. In addition of inhibitors of mitogen activated protein kinase, inhibitors of the proteasome, mesenchymal stem cells started to be used 13 years ago to prevent or diminish the organ’s injuries. Mesenchymal stem cells (e.g bone marrow stem cells, adipose derived stem cells) have proven to be powerful tools in repairing damaged organs. This review will focus on the use of some bone marrow stem cells, adipose derived stem cells and umbilical cord stem cells on preventing or decreasing the injuries due to ischemia-reperfusion.
ARTICLE | doi:10.20944/preprints201905.0135.v1
Subject: Biology And Life Sciences, Animal Science, Veterinary Science And Zoology Keywords: Skin; Cell culture; Stem cells; Differentiation; Camel
Online: 10 May 2019 (15:04:59 CEST)
Elite camels often suffer from massive injuries. Thus, there is a pivotal need for a cheap and readily available regenerative medicine source. We isolated novel stem-like cells from camel skin and investigated their multipotency and resistance against various stresses. Skin samples were isolated from ears of five camels. Fibroblasts, keratinocytes, and spheroid progenitors were extracted. After separation of different cell lines by trypsinization, all cell lines were exposed to heat shock. Then, fibroblasts and dermal cyst-forming cells were examined under cryopreservation. Dermal cyst-forming cells were evaluated for resistance against osmotic pressure. The results revealed that resistance periods against trypsin were 1.5, 4, and 7 minutes for fibroblasts, keratinocytes, and spheroid progenitors, respectively. Furthermore, complete recovery of different cell lines after heat shock along with the differentiation of spheroid progenitors into neurons was observed. Fibroblasts and spheroid progenitors retained cell proliferation after cryopreservation. Dermal cyst-forming cells regained their normal structure after collapsing by osmotic pressure. The spheroid progenitors incubated in the adipogenic, osteogenic, and neurogenic media differentiated into the adipocytes, osteoblasts, and neurons, respectively. To the best of our knowledge, we isolated different unique cellular differons and stem-like cells from the camel skin and examined their multipotency for the first time.
ARTICLE | doi:10.20944/preprints201807.0264.v1
Subject: Chemistry And Materials Science, Medicinal Chemistry Keywords: Orotic hydrazide, Arylhydrazone, Mesenchymal Stem Cells, Proliferation
Online: 16 July 2018 (09:06:33 CEST)
Human mesenchymal stem cells (hMSCs) constitute of cells having potential of self-renewal and proliferation and are commonly isolated from bone marrow aspirates of large bones. The osteogenic potential of these stem cells has been extensively exploited by scientists during the last many years for the biological evaluation of synthetic scaffolds with applications in tissue engineering. Current work aimed to synthesize N-arylhydrazone derivatives of orotic acid and their evaluation as stimulators of human mesenchymal stem cells. Some of the analogs show good to moderate proliferation rate.
ARTICLE | doi:10.20944/preprints201708.0077.v1
Subject: Environmental And Earth Sciences, Atmospheric Science And Meteorology Keywords: Lightning; Stepped leader; Space leader; Space stem
Online: 22 August 2017 (17:28:25 CEST)
A physical model based on the mechanism observed in experimental investigations is introduced to describe the formation of negative leader steps. Starting with a small length of a space leader located at the periphery of the negative streamer system of the stepped leader the model simulates the growth and the subsequent formation of the leader step. Based on the model, the average step length, the average step forming time and the average stepped leader propagation speed is estimated as a function of prospective return stroke peak current. The results show that the average step length and the average leader speed increases with increasing prospective return stroke current. The results also show that the speed of the stepped leader increases as it approaches the ground. For a 30 kA prospective return stroke current the average leader speed obtained is about 5 x 105 m/s and the average step length was about 10 m. The results obtained are in reasonable agreement with the experimental observations.
ARTICLE | doi:10.20944/preprints202303.0185.v1
Subject: Biology And Life Sciences, Biology And Biotechnology Keywords: allogenic; cell-based therapies; clinical trials; ligament; mesenchymal stem cells; sport horses; syn-ovial mesenchymal stem cell; tendon
Online: 10 March 2023 (02:53:15 CET)
Tendons and ligaments injuries are frequent in sport horses and humans, representing a great therapeutic challenge. Tissue regeneration and function recovery are the paramount of tendon and ligament lesions management. Nowadays, several regenerative treatments are being developed, based on the use of stem cell and stem cell-based therapies. In the present study, the preparation of equine synovial membrane mesenchymal stem cells (eSM-MSCs) for clinical use - collection, transport, isolation, differentiation, characterization, and application is described. These cells are fibroblast-like and grow in clusters. They retain an osteogenic, chondrogenic and adipogenic differentiation potential. 16 clinical cases of tendonitis and desmitis, treated with allogenic eSM-MSCs and autologous serum are also presented, including their evaluation, treatment and follow-up. The use of autologous serum as a vehicle concern to a decreased immunogenic response after the administration of this combination and to its healing properties, due to the presence of growth factors and immunoglobulins. Most of the cases (14/16), healed in 30 days and presented a good outcome. Treatment of tendon and ligament lesions with the mixture of eSM-MSCs and autologous serum appears to be a promising clinical option for this category of lesions in equine patients.
ARTICLE | doi:10.20944/preprints202108.0444.v1
Subject: Physical Sciences, Biophysics Keywords: actin cytoskeleton; super-resolution microscopy; embryonic stem cells; primed embryonic stem cells; micro-rheology; cell culturing; optical tweezers
Online: 23 August 2021 (13:31:33 CEST)
The cellular cytoskeleton provides the cell with a mechanical rigidity which allows mechanical interaction between cells and the extracellular environment. The actin structure plays a key role in mechanical events like motility, or establishment of cell polarity. From the earliest stages of development, as represented by ex vivo expansion of naïve embryonic stem cells (ESCs), the critical mechanical role of the actin structure is becoming recognized as a vital cue for correct segregation and lineage control of cells and as a regulatory structure that controls several transcription factors. Naïve ESCs have a characteristic morphology and the ultrastructure that underlies this condition remains to be further investigated. Here, we investigate the 3D actin cytoskeleton of naïve mouse ESCs using super resolution optical reconstruction microscopy (STORM). We investigate the morphological, cytoskeletal and mechanical changes in cells cultured in 2i or Serum/LIF media reflecting a homogenous preimplantation cell state and a state that is closer to embarking on differentiation. STORM imaging showed that the peripheral actin structure undergoes a dramatic change between the two media conditions. We also detected micro-rheological differences in the cell periphery between the cells cultured in these two media correlating well with the observed nano-architecture of the ESCs in the two different culture conditions. These results pave the way for linking physical properties and cytoskeletal architecture to cell morphology during early development.
ARTICLE | doi:10.20944/preprints202203.0143.v1
Subject: Biology And Life Sciences, Cell And Developmental Biology Keywords: human pluripotent stem cells; human embryonic stem cells; human induced pluripotent stem cells; cellular metabolism; oxygen; self-renewal; pluripotency; differentiation; volatile organic compounds; Selected ion flow tube-mass spectrometry
Online: 10 March 2022 (10:23:46 CET)
Human pluripotent stem cells (hPSCs) have widespread potential biomedical applications. There is a need for large-scale in vitro production of hPSCs, and optimal culture methods are vital in achieving this. Physiological oxygen (2% O2) improves key hPSCs attributes, including genomic integrity, viability, and clonogenicity, however, its impact on hPSC metabolism remains un-clear. Here, Selected Ion Flow Tube-Mass Spectrometry (SIFT-MS) was used to detect and quantify metabolic Volatile Organic Compounds (VOCs) in the headspace of hPSCs and their differentiated progeny. hPSCs were cultured in either 2% O2 or 21% O2. Media was collected from cell cultures and transferred into glass bottles for SIFT-MS measurement. The VOCs acetaldehyde and dimethyl sulfide (DMS)/ethanethiol were significantly increased in undifferentiated hPSCs compared to their differentiating counterparts, and these observations were more apparent in 2% O2. Pluripotent marker expression was consistent across both O2 concentrations tested. Transcript levels of ADH4, ADH5, and CYP2E1, encoding enzymes involved in converting ethanol to acetaldehyde, were upregulated in 2% O2, and chemical inhibition of ADH and CYP2E1 decreased acetaldehyde levels in hPSCs. Acetaldehyde and DMS/ethanethiol may be indicators of altered metabolism pathways in physiological oxygen culture conditions. The identification of non-destructive biomarkers for hPSC characterization has the potential to facilitate large-scale in vitro manufacture for future biomedical application.
ARTICLE | doi:10.20944/preprints202305.1216.v1
Subject: Medicine And Pharmacology, Other Keywords: Adipose-derived stem cells; human cell therapy; mesenchymal stem cells; endothelial cells; pericytes; GMP-compliant-facility; clean room; ATMPs
Online: 17 May 2023 (09:53:20 CEST)
The adipose-derived mesenchymal stem cells are becoming the tool of choice for many clinical applications and nowadays, nearly 200 clinical trials are running worldwide to prove the efficacy of this cell type for many diseases and pathological conditions. To reach the goal of cell therapies and produce ATMPs as drugs for regenerative medicine, it is necessary to properly standardize the GMP processes and thus collection methods, transportation strategies, extraction protocols and characterization procedures without forgetting that all the tissues of the human body are characterized by a wide inter-individual variability genetically determined and acquired during life. Here we compare 302 samples processed under GMP rules to exclude the influence of the operator and of the anatomical site of collection. Variability in the age of patients, gender and laboratory parameters like total cell number, cell viability, stem cell number and other stromal vascular fraction cell sub-populations have been compared to each other. Results show that, when the laboratory protocol is standardized, the variability in quantifiable cell parameters is widely statistically non-significant, meaning that we can make a further step toward standardized advanced cell therapy products.
ARTICLE | doi:10.20944/preprints202305.0482.v1
Subject: Biology And Life Sciences, Biochemistry And Molecular Biology Keywords: Mitochondria; Personalized Oncology; cancer stem cell; T Cell
Online: 8 May 2023 (08:48:56 CEST)
Energy is needed by cancer cells to stay alive and communicate with their surroundings. The primary organelles for cellular metabolism and energy synthesis are mitochondria. Researchers recently proved that cancer cells can steal immune cells' mitochondria using nanoscale tubes. This finding demonstrates the dependence of cancer cells on normal cells for their living and function. It also denotes the importance of mitochondria in cancer cells’ biology. Emerging evidence has demonstrated how mitochondria are essential for cancer cells to survive in the harsh tumor microenvironment, evade the immune system, obtain more aggressive features, and resist treatments. For instance, functional mitochondria can improve cancer resistance against radiotherapy by scavenging the released reactive oxygen species. Therefore, targeting mitochondria can potentially enhance oncological outcomes, according to this notion. The patients' reactions to radiation are varied, ranging from a complete response to even cancer progression during treatment. This concept illustrates how different levels of mitochondrial metabolism might contribute to this heterogeneity. Considering this notion can help to improve personalized oncological treatments. This article outlines the importance of mitochondrial metabolism in cancer biology and personalized treatments.
HYPOTHESIS | doi:10.20944/preprints202303.0449.v1
Subject: Biology And Life Sciences, Cell And Developmental Biology Keywords: unstable state cells, growth limit, stem cells, traits
Online: 27 March 2023 (07:50:59 CEST)
Multicellular organisms organize themselves according to two principles; first, the equilibrium between the driving force of unstable state cells and apoptosis or senescence; and second, the mutual equilibrium between the functional requirements of different types of cells. For the first principle, we deduce that stem cells at different levels have their own growth limits, which are determined by two factors: the ability of the stem cells to enter an unstable state (specifically, the ability of cells to divide and differentiate); and the rate of cellular senescence, loss of function, and finally, apoptosis. The superposition of stem cell limits at different levels over each other can amplify small differences at the genetic level. Moreover, the growth limits of different organs are different, which lead to different individuals having completely different appearances. The second principle is that the sum of the specific output functions of an organ must be equal to the overall demand for the function to be provided by the organ. If negative entropy input can meet this equilibrium, defects in certain genes will cause these defective individuals to become larger or develop other morphology.
ARTICLE | doi:10.20944/preprints202210.0308.v1
Subject: Medicine And Pharmacology, Oncology And Oncogenics Keywords: Glioma; Glioblastoma; Glioma stem-like cells; CHRDL1; BMP4
Online: 20 October 2022 (11:20:23 CEST)
Glioblastoma (GBM) still presents as one of the most aggressive tumors in the brain, which despite enormous research efforts remains incurable until today. As many theories evolve around the persistent recurrence of this malignancy the assumption of a small population of cells with a stem-like phenotype remains as a key driver of its infiltrative nature. In this article we research Chordin-like 1 (CHRDL1), a secreted protein, as a potential key regulator of the glioma stem-like cell (GSC) phenotype. It has been shown that CHRDL1 antagonizes the function of Bone Morphogenic Protein 4 (BMP4), which induces GSC differentiation and hence reduces tumorigenicity. We therefore employed two previously described GSCs spheroid cultures and depleted them of CHRDL1 using stable transduction of a CHRDL1-targeting shRNA. We show with in vitro cell based assays (MTT, limiting dilution and sphere formation assays), western blots, irradiation procedures and quantitative real-time PCR that depletion of the secreted BMP4 antagonist CHRDL1 prominently decreases functional and molecular stemness traits resulting in enhanced radiation sensitivity. As a result, we postulate CHRDL1 as an enforcer of stemness in GSCs and find additional evidence that high CHRDL1-expression might also serve as a marker protein to determine BMP4-susceptibility.
ARTICLE | doi:10.20944/preprints202111.0356.v1
Subject: Chemistry And Materials Science, Materials Science And Technology Keywords: additive manufacturing; microstructure; STEM in situ heating experiments
Online: 19 November 2021 (14:23:25 CET)
Powder and SLM additively manufactured parts of X5CrNiCuNb17-4 maraging steel were systematically investigated by electron microscopy to understand the relationship between the properties of the powder grains and the microstructure of the printed parts. We prove that satellites, irregularities and superficial oxidation of powder particles can be transformed into an advantage through the formation of nanoscale (AlMnSiTiCr)-oxides in the matrix during the printing process. The nano-oxides showed extensive stability in terms of size, spherical morphology, chemical composition and crystallographic disorder upon in situ heating up to 950°C in the scanning transmission electron microscope. Their presence thus indicates a potential for oxide-dispersive strengthening of this steel, which may be beneficial for creep resistance at elevated temperatures. The nucleation of copper clusters and their evolution into nanoparticles as well as the precipitation of Ni and Cr particles upon in situ heating have as well been systematically documented.
ARTICLE | doi:10.20944/preprints202110.0276.v1
Subject: Biology And Life Sciences, Biology And Biotechnology Keywords: Mesenchymal stem cells; collagen type I; remodeling; oxidation
Online: 19 October 2021 (12:19:16 CEST)
Abstract: The effect of collagen type 1 (Col I) oxidation on Adipose Tissue-Derived Mesenchymal Stem Cells (ADMSCs) remodeling is described as a model for acute oxidative stress. Morphologically, remodeling was presented by a mechanical rearrangement of adsorbed FITC-Col I and a trend for its organization in a fibril-like pattern - a process strongly abrogated in oxidized samples, but without visible changes in cell morphology. The cellular proteolytic activity was quantified in multiple samples utilizing fluorescence de-quenching (FRET effect). In the presence of ADMSCs a significant increase of native FITC-Col I fluorescence was observed, almost absent in the oxidized samples. Parallel studies in cell-free systems confirmed the enzymatic de-quenching of native FITC-Col I by Clostridial collagenase, again showing significant inhibition in oxidized samples. The structural changes in the oxidized Col I was further studied by Differential Scanning Calorimetry: an additional endotherm at 33.6°C along with the typical for native Col I at 40.5°C with sustained enthalpy (∆H) was observed in oxidized samples. Collectively, it has been evidenced that remodeling of Col I by ADMSCs is altered upon oxidation due to the intrinsic changes in the protein structure, thus presenting a novel mechanism for the control of stem cells' behavior toward collagen.
ARTICLE | doi:10.20944/preprints202109.0158.v1
Subject: Biology And Life Sciences, Biochemistry And Molecular Biology Keywords: intravenous leiomyomatosis; leiomyoma; leiomyosarcoma; tumor stem-like cells
Online: 8 September 2021 (20:00:08 CEST)
Background/Aim: Uterine leiomyoma, also known as fibroids, is the most common benign neoplasm of the female genital tract. Leiomyoma, including its subtypes, is the most common uterine tumor. The subtypes account for approximately 10% of leiomyomas. Intravenous leiomyomatosis, a uterine leiomyoma subtype, is an intravascular growth of benign smooth muscle cells, occasionally with pelvic or extrapelvic extension. Uterine leiomyosarcoma, a malignant tumor, tends to metastasize hematogenously, and distant metastasis to the lungs and liver is common. Therefore, this intravenous leiomyomatosis’ oncological features resemble those of the malignant tumor uterine leiomyosarcoma. Cancer stem cells migrate to distant organs via intravascular infiltration, leading to micrometastases. Materials and Methods: We examined the oncological properties of intravenous leiomyomatosis using molecular pathological techniques on tissue excised from patients with uterine leiomyoma. Result: CD44-positive mesenchymal tumor stem-like cells were detected in both intravenous leiomyomatosis and uterine leiomyosarcoma. The oncological nature of intravenous leiomyomatosis was found to be similar to the oncological properties of uterine leiomyosarcoma. However, in intravenous leiomyomatosis, Cyclin E and Ki-67-positive cells were rare, and no pathological findings suspected to be malignant were observed. Conclusion: It is expected that establishing a treatment method targeting cancer stem cells will lead to the treatment of malignant tumors with a low risk of recurrence and metastasis.
ARTICLE | doi:10.20944/preprints202106.0691.v1
Subject: Biology And Life Sciences, Biochemistry And Molecular Biology Keywords: Calcitriol; Vitamin D3; Glioblastoma; Glioblastoma stem-like cells
Online: 29 June 2021 (08:37:43 CEST)
: Glioblastoma (GBM) is the most common and most aggressive primary brain tumor with a very high rate of recurrence and a median survival of 15 months after diagnosis. Abundant evi-dence suggests that a certain sub-population of cancer cells harbors a stem-like phenotype and is likely responsible for disease recurrence, treatment resistance and potentially even for the infil-trative growth of GBM. GBM incidence has been negatively correlated with the serum levels of 25-hydroxy-vitamin D3, while the low pH within tumors has been shown to promote the ex-pression of the vitamin D3-degrading enzyme 24-hydroxylase, encoded by the CYP24A1 gene. Therefore, we hypothesized that calcitriol can specifically target stem-like glioblastoma cells and induce their differentiation. Here, we show using in vitro limiting dilution assays, quantita-tive real-time PCR and ex vivo adult organotypic brain slice transplantation cultures that thera-peutic doses of calcitriol, the hormonally active form of vitamin D3, reduces stemness to varying extent in a panel of investigated GSC lines and effectively hinders tumor growth of responding GSCs ex vivo. We further show that calcitriol synergizes with Temozolomide ex vivo to com-pletely eliminate some GSC tumors. These findings indicate that calcitriol carries potential as an adjuvant therapy for a subgroup of GBM patients and should be analyzed in more detail in fol-low-up studies.
ARTICLE | doi:10.20944/preprints202106.0115.v1
Subject: Medicine And Pharmacology, Immunology And Allergy Keywords: triterpenoids; Acacia stem bark; polypharmacology; protein kinase inhibitors
Online: 3 June 2021 (13:04:47 CEST)
The purpose of this work is to investigate the protein kinase inhibitory activity of constituents from ethyl acetate soluble fraction of Acacia auriculiformis stem bark. Column chromatography, gel filtration and NMR spectroscopy were used to purified and characterized betulin from the extract. Betulin which is a known inducer of apoptosis was screened against a panel of 16 disease-related protein kinases. Betulin was shown to inhibit Abelson murine leukemia viral oncogene homolog 1 (ABL1) kinase, casein kinase 1epsilon (CK1epsilon), glycogen synthase kinase 3alpha/β (GSK-3alpha/β), Janus kinase 3 (JAK3), NIMA Related Kinase 6 (NEK6) and vascular endothelial growth factor receptor 2 kinase (VEGFR2) and with activity in µM range. The effect of betulin on the cell viability of doxorubicin-resistant K562R chronic myelogenous leukemia cells was then verified to underline its putative use as anti-cancer compound. Betulin was shown to modulate the mitogen-activated protein (MAP) kinase pathway similarly to imatinib mesylate, a well-known inhibitor of ABL1 kinase. The interaction of betulin and ABL1 was studied by molecular docking showing an interaction of the inhibitor with the ATP binding pocket. Altogether, these data demonstrate that betulin is a multi-target inhibitor of protein kinases, an activity that can contribute to the anticancer properties of the natural compound and notably for treatment of leukemia.
REVIEW | doi:10.20944/preprints202101.0099.v1
Subject: Biology And Life Sciences, Anatomy And Physiology Keywords: biomedical model; hearing impairment; regeneration; stem cells; zebrafish
Online: 5 January 2021 (14:23:23 CET)
Zebrafish is an excellent model for observing human genetic disorders. Hearing impairment is the most common genetic disorder including syndromic & non-syndromic hearing loss. Stem cell therapies are considered a new hope in case of hearing impairment. Stem cells are the master cells of the human body and having the capability to differentiate into any other form of cells in more than 200 types of cells (regeneration). This review article describes zebrafish as a biomedical model for stem cell research in hearing impairment, which revolutionized the biomedical arena to compete for the challenges.
Subject: Medicine And Pharmacology, Immunology And Allergy Keywords: cancer stem cell; epithelial-mesenchymal transition; molecular network
Online: 25 November 2020 (13:47:19 CET)
Epithelial-mesenchymal transition (EMT) plays an important role in the acquisition of cancer stem cell (CSC) feature and drug resistance, which are the main hallmarks of cancer malignancy. Although previous findings have shown that several signaling pathways are activated in cancer progression, the precise mechanism of signaling pathways in EMT and CSCs are not fully understood. In this study, we focused on the intestinal and diffuse-type gastric cancer (GC), and analyzed the gene expression of public RNAseq data to understand the molecular pathway regulation in different subtypes of gastric cancer. Network pathway analysis was performed by Ingenuity Pathway Analysis (IPA). Total 2815 probe set IDs were significantly different between intestinal- and diffuse-type GC data in cBioPortal Cancer Genomics. The 10 genes including male-specific lethal 3 homolog (Drosophila) pseudogene 1 (MSL3P1), CDC28 protein kinase regulatory subunit 1B (CKS1B), DEAD-box helicase 27 (DDX27), golgi to ER traffic protein 4 (GET4), chromosome segregation 1 like (CSE1L), translocase of outer mitochondrial membrane 34 (TOMM34), YTH N6-methyladenosine RNA binding protein 1 (YTHDF1), ribonucleic acid export 1 (RAE1), par-6 family cell polarity regulator beta (PARD6B), and MRG domain binding protein (MRGBP) were found to have difference in gene expression in intestinal- and diffuse-type GC. Total 463 direct relationships with 3 molecules (MYC, NTRK1, UBE2M) were found in the biomarker-filtered network generated by network pathway analysis. The networks and features in intestinal- and diffuse-type GC have been investigated and profiled in bioinformatics. Our results revealed the signaling pathways networks in intestinal- and diffuse-type GC, bringing new light for the elucidation of drug resistance mechanisms in CSCs.
ARTICLE | doi:10.20944/preprints202011.0349.v1
Subject: Medicine And Pharmacology, Immunology And Allergy Keywords: mesenchymal stem cell; beta-tricalcium phosphate; hydroxyapatite; osteogenesis.
Online: 12 November 2020 (13:16:15 CET)
Bone innate ability to repair without scaring is surpassed by major bone damage. Current gold-standard strategies do not achieve a full recovery of bone biomechanical properties. To bypass these limitations, tissue engineering techniques based on hybrid materials made up of osteoprogenitor cells, like mesenchymal stem cells (MSCs), and bioactive ceramic scaffolds, like calcium phosphate-based (CaPs), are promising. Biological properties of the MSCs, are influenced by the tissue source. The aim of this study is to define the MSC source and construct (MSC and scaffold combination) most interesting for its clinical application in bone regeneration. iTRAQ generated the hypothesis that anatomical proximity to bone has a direct effect on MSC phenotype. MSCs were isolated from adipose tissue, bone marrow and dental pulp. MSCs were cultured both on plastic surface and on CaPs (hydroxyapatite and β-tricalcium phosphate) to compare their biological features. On plastic, MSCs isolated from dental pulp (DPSCs) were the MSCs with the highest proliferation capacity and the greatest osteogenic potential. On both CaPs, DPSCs are the MSCs with the greatest capacity to colonize bioceramics. Furthermore, results show a trend for DPSCs are the MSCs with the most robust increase in the ALP activity. We propose DPSCs as a suitable MSCs for bone regeneration cell-based strategies.What do you want to do ?New mailCopy
ARTICLE | doi:10.20944/preprints202010.0176.v1
Subject: Computer Science And Mathematics, Information Systems Keywords: Virtual Reality; Learning Analytics; STEM Education; Instructional Design.
Online: 8 October 2020 (13:02:32 CEST)
The commercial popularity of Virtual Reality attracted educators’ interest and brought new opportunities to the educational landscape. At the same time, Learning Analytics emerged with the promise to revolutionise the traditional practices by introducing ways to systematically assess and improve the effectiveness of instruction. However, the collection of ‘big’ educational data is mostly associated with web-based platforms as they offer direct access to learners’ activities with minimal effort. On the antipode, the nature of VR limits the opportunities for such data collection. Hence, in the context of this work, we present a four-dimensional theoretical framework, that accounts the information that can be gathered from VR-supported instruction, and propose a set of structural elements which can be utilised for the development of a Learning Analytics prototype system. The outcomes of this work are expected to support practitioners to maximise the potential of their interventions and provide inspiration for new ones.
ARTICLE | doi:10.20944/preprints202008.0403.v1
Subject: Biology And Life Sciences, Cell And Developmental Biology Keywords: sickle cell disease; hematopoietic stem cells; hydroxyurea; transfusion
Online: 19 August 2020 (08:38:35 CEST)
The consequences of Sickle Cell Disease (SCD), including ongoing hematopoietic stress and hemolysis, vascular damage and chronic therapies , such as blood transfusions and Hydroxyurea on hematopoietic stem and progenitor cell (HSPC) have not been characterized. We have quantified the frequencies of nine HSPC populations by flow cytometry in the peripheral blood of pediatric and adult patients stratified by treatment and controls. We observed broad differences between SCD patients and healthy controls. SCD is associated with 10 to 20-fold increase in CD34dim cells, and two to five-fold more CD34bright cells, a depletion in Megakaryocyte-Erythroid Progenitors and an increase in hematopoietic stem cells, when compared to controls. SCD is also associated with abnormal expression of CD235a and by very high levels of expression of the CD49f antigen. These findings were present to varying degrees in all patients, whether or not they were naïve or on chronic therapy. HU treatment tended to normalizes many of these parameters. Chronic stress erythropoiesis, inflammation caused by SCD and hydroxyurea therapy have long been suspected of causing premature aging of the hematopoietic system, and potentially increasing the risk of hematological malignancies. An important finding of this study was that the observed concentration of CD34bright cells and of all the HSPCs decreased logarithmically with time of treatment with HU. This correlation was independent of age and specific to HU treatment. Although the number of circulating HSPCs is influenced by many parameters, our findings suggest that HU treatment may decrease premature aging and hematologic malignancy risk compared to the other therapeutic modalities in SCD.
REVIEW | doi:10.20944/preprints202004.0028.v1
Subject: Social Sciences, Psychology Keywords: brain organoids; stem cells; brain in a vat
Online: 3 April 2020 (08:14:18 CEST)
Along just over a century of research we moved from learning how to cultivate tissues in a dish to grasping the concepts for creating an entire brain in a vat. As we approach the divisive moment in which we can first detect signs of awareness in such artificially developed organoids, we need to lay foundation for what lays ahead. It is crucial that ethical, legal and moral implications of organoid research are clear and that boundaries are set to separate scientific progress from human life preservation. The largest obstacle may be the definition of consciousness itself, which has arguably been historically neglected by philosophy, psychology and neurosciences at large. One reason may be the difficulties posed by the underlying qualities of awareness, such as its subjective and heterogeneous nature. Another reason may lie on the possibly that consciousness is an overarching emergent property of our brain. For the time being, one can see brain organoids as philosophical zombies, physical analogues of the human brain which mimic sentient human reactions but lack experiential properties of sensation (a.k.a. qualia).
REVIEW | doi:10.20944/preprints201911.0170.v1
Subject: Biology And Life Sciences, Cell And Developmental Biology Keywords: PI3K signalling; cancer; stemness; pluripotent stem cells; development
Online: 15 November 2019 (03:59:00 CET)
The PI3K/AKT pathway is a key target in oncology where most efforts are focussed on phenotypes such as cell proliferation and survival. Comparatively little attention has been paid to PI3K in stemness regulation, despite the emerging link between acquisition of stem cell-like features and therapeutic failure in cancer. The aim of this review is to summarise current known and unknowns of PI3K-dependent stemness regulation, by integrating knowledge from the fields of developmental, signalling and cancer biology. Particular attention is given to the role of the PI3K pathway in pluripotent stem cells (PSCs) and the emerging parallels to dedifferentiated cancer cells with stem cell-like features. Compelling evidence suggests that PI3K/AKT signalling forms part of a ‘core molecular stemness programme’ in both mouse and human PSCs. In cancer, the oncogenic PIK3CAH1047R variant causes constitutive activation of the PI3K pathway and has recently been linked to increased stemness in a dose-dependent manner, similar to observations in mouse PSCs with heterozygous versus homozygous Pten loss. There is also evidence that the stemness phenotype may become ‘locked’ and thus independent of the original PI3K activation, posing limitations for the success of PI3K monotherapy in cancer.Ongoing therapeutic developments for PI3K-associated cancers may therefore benefit from a better understanding of the pathway’s two-layered and highly context-dependent regulation of cell growth versus stemness.
ARTICLE | doi:10.20944/preprints201811.0482.v1
Subject: Chemistry And Materials Science, Biomaterials Keywords: polycaprolactone; oxygen plasma; Wharton’s Jelly mesenchymal stem cells
Online: 20 November 2018 (05:26:00 CET)
Cell-based therapies and tissue engineering applications require biocompatible substrates that support and regulate the growth, survival, and differentiation of specific cell types. Extensive research efforts in regenerative medicine are devoted to the development of tunable biomaterials which support various cell types including stem cells. In this research, the non-cytotoxic biopolymer polycaprolactone (PCL) was fabricated into 2D and 3D scaffolds with or without the low-pressure oxygen plasma treatment to enhance hydrophilicity. Cellular responses and biocompatibility were evaluated using a human Wharton’s jelly mesenchymal stem cell line (BCP-K1). The 2D PCL scaffolds enhanced initial cell attachment compared to the 3Ds indicated by a higher expression of focal adhesion kinase (FAK). Whilst, the 3D scaffolds promoted cell proliferation and migration as evidenced by higher cyclin A expression and filopodial protrusion, respectively. The 3D scaffolds potentially protected the cell entering to apoptosis/necrosis program and induced cell differentiation, evaluated by gene expression. Both 2D and 3D PCL appeared to have stronger effects on cell behavior than a control substrate (polystyrene). In summarize, the different configuration and surface properties of PCL scaffolds provide various options for modulation of stem cell behaviors, including attachment, proliferation, survival, and differentiation, when combined with specific growth factors and culture conditions.
REVIEW | doi:10.20944/preprints201809.0047.v1
Subject: Chemistry And Materials Science, Biomaterials Keywords: Graphene oxide; Stem cells; Growth; Cell differentiation; Biomaterials
Online: 3 September 2018 (15:44:08 CEST)
Stem cells are undifferentiated cells which can give rise to any types of cells in our body. Hence, they have been utilized for various applications such as drug testing and disease modeling. However, for the successful of those applications, the survival and differentiation of stem cells into specialized lineages should be well controlled. Growth factors and chemical agents are the most common signals to promote the proliferation and differentiation of stem cells. However, those approaches holds several drawbacks such as the negative side effects, degradation or denaturation, and expensive. To address such limitations, nanomaterials have been recently used as a better approach for controlling stem cells behaviors. Graphene oxide is the derivative of graphene, the first 2D materials in the world. Recently, due to its extraordinary properties and great biological effects on stem cells, many scientists around the world have utilized graphene oxide to enhance the differentiation potential of stem cells. In this mini review, we highlight the key advances about the effects of graphene oxide on controlling stem cell growth and various types of stem cell differentiation. We also discuss the possible molecular mechanisms of graphene oxide in controlling stem cell growth and differentiation.
REVIEW | doi:10.20944/preprints201806.0262.v1
Subject: Biology And Life Sciences, Biochemistry And Molecular Biology Keywords: ovarian cancer; cancer stem cells; signaling, chemoresistance, metastasis
Online: 15 June 2018 (15:14:22 CEST)
Ovarian cancer is the most lethal gynecological malignancy. Poor overall survival, particularly for patients with high grade serous (HGS) ovarian cancer, are often attributed to late stage at diagnosis and relapse following chemotherapy. HGS ovarian cancer is a heterogenous disease in that few genes are consistently mutated between patients. Additionally, HGS ovarian cancer is characterized by high genomic instability. For these reasons personalized approaches may be necessary for effective treatment and cure. Understanding the molecular mechanisms that contribute to tumor metastasis and chemoresistance are essential to improve survival rates. One favored model for tumor metastasis and chemoresistance is the cancer stem cell (CSC) model. CSCs are cells with enhanced self-renewal properties that are enriched following chemotherapy. Elimination of this cell population is thought to be a mechanism to increase therapeutic response. Therefore, accurate identification of stem cell populations that are most clinically relevant is necessary. While many CSC identifiers (ALDH, OCT4, CD133, and side population) have been established, it is still not clear which population(s) will be most beneficial to targeted in patients. Therefore, there is a critical need to characterize CSCs with reliable markers and find their weaknesses that will make the CSCs amenable to therapy. Many signaling pathways are implicated for their roles in CSC initiation and maintenance. Therapeutically targeting pathways needed for CSC initiation or maintenance may be an effective way of treating HGS ovarian cancer patients. In conclusion, the prognosis for HGS ovarian cancer may be improved by combining CSC phenotyping with targeted therapies for pathways involved in CSC maintenance.
ARTICLE | doi:10.20944/preprints202109.0139.v1
Subject: Biology And Life Sciences, Cell And Developmental Biology Keywords: Adipose-derived Stem Cell; Flow-Cytometry; Mesenchymal Stem Cell; Stromal Vascular Fraction; Immunophenotyping; Immunohistochemistry; Fluorescent Antibody Technique; Cell Separation Method
Online: 8 September 2021 (10:50:49 CEST)
Background: Developing an efficient and standardized method to isolate and characterize adipose-derived stem cells (ASCs) from the stromal vascular fraction (SVF) of the adipose tissue for clinical application represents one of the major challenges in cell therapy and tissue engineering. Methods: In this study, we proposed an innovative, non-enzymatic protocol to collect clinically useful ASCs within freshly isolated SVF from adipose tissue by centrifugation of the infranatant portion of lipoaspirate and to determine the characteristic cytofluorimetric pattern, prior to in vitro culture. Results: The SVF yielded a mean of 73,32 \pm\ 10,89% cell viability evaluated with CALCEINA-FITC, i.e. cell-permeant dye. The ASCs were positive for PC7-labeled mAb anti-CD34 and negative for both PE-labeled mAb anti-CD31 and APC-labeled mAb anti-CD45. The frequency of ASCs estimated according to the panel of cell surface markers used was 51,06%\ \pm 5,26% versus the unstained ASCs subpopulation that was 0,74%\pm0,84% (P<0.0001). The ASCs events/\muL were 1602,13/\muL \pm 731,87/\muL. Conclusion: Our findings suggested that ASCs found in freshly isolated adipose SVF obtained by centrifugation of lipoaspirate can be immunophenotypically identified with a basic panel of cell surface markers. These findings aimed to provide standardization and contribute to reducing the inconsistency on reported cell surface antigens of ASC derived from the existing literature.
ARTICLE | doi:10.20944/preprints201708.0103.v1
Subject: Medicine And Pharmacology, Oncology And Oncogenics Keywords: stem cells; somatic mutations; cancer prevention; carcinogenesis; whole genome sequencing; stem cell division theory of cancer; bad luck of cancer
Online: 30 August 2017 (12:14:52 CEST)
Recent evidence indicates that the risk of being diagnosed with cancer in a tissue is strongly correlated (0.80) with the number of stem cell divisions accumulated by the tissue. Since cell division can generate random mutations during DNA replication, this correlation has been used to propose that cancer is largely caused by the accumulation of unavoidable mutations in driver genes. However, no correlation between the number of gene mutations and cancer risk across tissues has been reported. Because many somatic mutations in cancers originate prior to tumor initiation and the number of cell divisions occurring during tumor growth is similar among tissues, here I use whole genome sequencing information from 22,086 cancer samples and incidence data from the largest cancer registry in each continent to study the relationship between the number of gene mutations and the risk of cancer across 33 tissue types. Results show a weak positive correlation (mean = 0.14) between these two parameters in each of the five cancer registries. The correlation became stronger (mean = 0.50) when gender-related cancers were excluded. Results also show that 1,003 samples from 29 cancer types have zero mutations in genes. These data suggest that cancer etiology can be better explained by the accumulation of stem cell divisions than by the accumulation of gene mutations. Possible mechanisms by which the accumulation of cell divisions in stem cells increases the risk of cancer are discussed.
ARTICLE | doi:10.20944/preprints201702.0010.v1
Subject: Chemistry And Materials Science, Biomaterials Keywords: amorphous polyphosphate microparticles; retinyl acetate; enamel cracks/fissures; Streptococcus mutans; human mesenchymal stem cells; collagen type I; alkaline phosphatase
Online: 4 February 2017 (07:37:55 CET)
Here we report the preparation and characterization of a novel biomimetic toothpaste containing morphogenetically active amorphous polyphosphate (polyP) microparticles enriched with retinyl acetate (“a-polyP/RA-MP”). The spherical microparticles (average size, 550±120 nm), prepared by co-precipitating sodium-polyP with calcium chloride and supplemented with retinyl acetate, were incorporated into a basis toothpaste at a final concentration of 1% or 10%. The paste containing “a-polyP/RA-MP” significantly increased the growth of human mesenchymal stem cells (MSC), compared to a commercial toothpaste which acts rather inhibitory and the paste without polyP and retinyl acetate. qRT-PCR experiments revealed that the retinoid causes an induction of the expression of the MSC marker genes for osteoblast differentiation encoding collagen type I and alkaline phosphatase. On the other hand, the polyP ingredient, supplied as Zn-polyP microparticles (“Zn-a-polyP-MP”) strongly inhibited the growth of the cariogenic bacterium Streptococcus mutans. We demonstrate that the amorphous polyP-containing toothpaste, enriched with retinyl acetate, efficiently repairs both cracks/fissures and carious lesions in the tooth enamel, and reseals dentinal tubules, already after a 5 d treatment (brushing) of teeth twice daily for 5 min as examined by SEM and quantitative EDX analysis. The stability of the occlusion of dentin cracks even turned out to resist against short high power sonication treatment. Our results demonstrate that the novel toothpaste prepared here, containing amorphous polyP and retinyl acetate, is particularly suitable for prevention/repair of (cariogenic) damages of tooth enamel/dentin and for treatment of dental hypersensitivity.
ARTICLE | doi:10.20944/preprints201907.0347.v1
Subject: Medicine And Pharmacology, Ophthalmology Keywords: autograft; embryonic stem cells (ESC); growth factor (GF); hereditary retinal disease; induced pluripotent stem cells (iPSCs); Limoli retinal restoration technique (LRRT); mesenchymal stem cell (MSC); retinitis pigmentosa; spectral domain-optical coherence tomography (SD-OCT)
Online: 31 July 2019 (04:45:51 CEST)
To evaluate whether autologous mesenchymal cells, adipose derived stem cells and platelet-rich plasma, grafted into the supracoroideal space by surgical treatment according to Limoli retinal restoration technique (LRRT), can produce growth factors in order to exert a beneficial effect in retinitis pigmentosa (RP) patients. Twenty-one eyes underwent surgery and divided based on retinal foveal thickness ≤ 190 or >190 µm into group A and group B, respectively. The specific LRRT triad was grafted in a deep scleral pocket above the choroid of each eye. At 6-month follow-up, group B showed an improvement in residual close-up visus and sensitivity at microperimetry compared to group A. After an in-depth review of molecular biology studies concerning degenerative phenomena underlying the etiopathogenesis of RP, it can be confirmed that further research is needed on tapeto-retinal degenerations both from a clinical and molecular point of view to obtain better functional results. In particular, it is necessary to increase the number of patients, extend observation times, and treat subjects in the presence of still trophic retinal tissue to allow adequate biochemical and functional catering.
ARTICLE | doi:10.20944/preprints202305.2270.v1
Subject: Biology And Life Sciences, Agricultural Science And Agronomy Keywords: Sclerotinia stem rot; SSR; pathogen; canola/rapeseed; sclerotia; lesion
Online: 31 May 2023 (14:44:48 CEST)
Management of Sclerotinia stem rot (SSR) disease in Brassica napus is heavily reliant on prophylactic fungicide applications at flowering, which often provides inconsistent control depending on timing of ascospore release in the field and environmental conditions. Understanding host response to Sclerotinia sclerotiorum infection is essential for sustainable disease management in the future. This study determined the host response of nine B. napus varieties to four aggressive S. sclerotiorum isolates across two years by measuring four disease variables; area under the disease progress stairs (AUDPS), seed production, sclerotia number and average sclerotia weight. Brassica napus varieties varied greatly in their response to the four measured variables, with varieties producing the highest AUDPS not the same varieties that had the lowest seed production, the highest numbers of sclerotia or heaviest sclerotia. Repeating the experiment over two years using the same varieties and isolates identified the impact of environment as the most influential factor on measured disease variables, highlighting the complexity of disease responses to diverse isolates and host genotypes under different environments. It was recommended that both long-term (such as inoculum production) and short-term (such as seed production) disease outcomes be combined with lesion length measurement (i.e. AUDPS) for future host screening studies.
ARTICLE | doi:10.20944/preprints202304.0220.v1
Subject: Medicine And Pharmacology, Oncology And Oncogenics Keywords: breast cancer; cervical cancer; stem cells; docking; simulation; microRNA
Online: 11 April 2023 (10:14:48 CEST)
Breast and Cervical cancer are significant causes of morbidity and mortality among women worldwide. Usually, conventional therapies and early detection has shown success in metastasis and relapse rates and improved overall survival of the patients. The elimination of the efficacy of chemotherapies and target therapies because cancer stem cells create resistance against chemotherapy, metastasis, and relapse. Studies reveal that cancer stem cell markers are important for improving efficiencies of targeted therapies. Our study aims to analyze the stem cell markers and target the most significant stem cell marker by phytochemicals and their derivates. Through the analysis, it was observed that CXCR4 and SOX-2, mir-1, mir-125, and mir-429 may have a crucial role in stemness of breast and cervical cancer respectively, while BPMD & MD simulations revealed Di-valinoyl curcumin as a potential compound for CXCR4 targeting.
ARTICLE | doi:10.20944/preprints202301.0108.v1
Subject: Biology And Life Sciences, Horticulture Keywords: asexual reproduction; Ericaceae; growth regulator; rooting rate; stem cutting
Online: 6 January 2023 (01:27:14 CET)
Studies on the cutting propagation of plants belonging to the genus Rhododendron are limited to R. mucronulatum and R. yedoense, which are mainly used as ornamental flowering trees, and additional studies on a greater variety of species are required. This study examined the characterisitics of cutting propagation according to treatment with growth regulators indole-3-butyric acid (IBA) and α-naphthaleneacetic acid (NAA) to generate basic data on the methods of reproducing R. micarnthum Turcz.. The number of roots (r=0.740**), length of root (r=0.844**), and number of leaves (r=0.649**) affected the rooting rate of R. micarnthum Turcz., and the number of roots (r=0.646**), length of roots (r=0.673**), number of leaves (r=0.738**), and chlorophyll content (r=0.710**) affected the survival rate. Further, the rooting and survival rates were highly correlated (r=0.794**). The growth characteristics of underground sections after growth regulator treatment were as follows: the number of formed roots was 7.0 and 7.2, and the length of roots was 6.2 cm and 5.3 cm in 150 mg·L-1 and 250 mg·L-1 NAA treatment groups, respectively. The rooting rate was 60% or above in the growth regulator treatment groups compared to that in the control group. Particularly, the rooting rates of 150 mg·L-1 and 250 mg·L-1 NAA treatment groups were 90% or above, and the latent period before rooting was shorter than other treatment groups at approximately 14 days, which was considered to be effective for root growth. The aboveground growth characteristics after propagating the cuttings showed that groups treated with 150 mg·L-1 and 250 mg·L-1 NAA showed a significantly higher plant length (5.2-5.8 cm), number of leaves (6.2 and 6.9), and leaf-length and leaf-width as compared to other treatment groups. Moreover, the survival rates of 150 mg·L-1 and 250 mg·L-1 NAA treatment groups were 80% or above, and the sound root growth manifested in the tendency of good aboveground growth. Additionally, IBA and NAA were highly correlated to the rooting and survival rates during cutting propagation of R. micarnthum Turcz.. The rooting and survival rates increased with the increase in growth regulator concentration. Particularly, NAA had a higher correlation to the rooting and survival rates than IBA (r=0.7316**, 0.7013**). Thus, R. micarnthum Turcz. could be propagated through cutting. Growth regulator treatment with 150 mg·L-1 and 250 mg·L-1 of NAA was effective for rooting and root growth of cutting, and these treatments were considered appropriate because the effects of aboveground growth were positive.
ARTICLE | doi:10.20944/preprints202210.0202.v1
Subject: Biology And Life Sciences, Biology And Biotechnology Keywords: gamma irradiation; 3D polycaprolactone; mesenchymal stem cells; cytocompatibility; biocompatibility.
Online: 14 October 2022 (03:43:22 CEST)
Additive manufacturing or 3D printing applying polycaprolactone-(PCL)-based medical devices represents an important branch of tissue engineering, where the sterilization method is a key process for further safe application in vitro and in vivo. In this study, the authors intend to access the most suitable gamma radiation conditions to sterilize PCL-based scaffolds in a preliminary biocompatibility assessment, envisioning future studies for airway obstruction conditions. Three radiation levels were considered, 25 kGy, 35 kGy and 45 kGy and evaluated as to their cyto- and biocompatibility. All three groups presented biocompatible properties, indicating an adequate sterility condition. As for the cytocompatibility analysis, devices sterilized by 35 kGy and 45 kGy showed better results, with the 45 kGy showing overall improved outcomes. This study allowed to select the most suitable sterilization condition for PCL-based scaffolds, aiming at immediate future assays, by applying 3D-customized printing techniques to specific airway obstruction lesions of the trachea.
ARTICLE | doi:10.20944/preprints202205.0001.v1
Subject: Biology And Life Sciences, Biochemistry And Molecular Biology Keywords: ovarian cancer; ALDH1A1; cancer stem cells; senescence; chemotherapy resistance
Online: 2 May 2022 (09:39:22 CEST)
Ovarian cancer is a deadly disease attributed to late-stage detection as well as recurrence and development of chemoresistance. Ovarian cancer stem cells (OCSCs) are hypothesized to be largely responsible for emergence of chemoresistant tumors. Although chemotherapy may initially succeed at decreasing the size and number of tumors, it leaves behind residual malignant OCSCs. In this study, we demonstrate that Aldehyde dehydrogenase 1A1 (ALDH1A1) is essential for the survival of OCSCs. We identified a novel ALDH1A1 inhibitor, compound 974, and used 974 as a tool to decipher the mechanism of stemness regulation by ALDH1A1. Treatment of OCSCs with 974 significantly inhibited ALDH activity, expression of stemness genes, spheroid, and colony formation. In vivo limiting dilution assay demonstrated that 974 significantly inhibited CSC frequency. Transcriptomic sequencing of cells treated with 974 revealed significant downregulation of genes related to stemness and chemoresistance as well as senescence and senescence associated secretory phenotype (SASP). We confirmed that 974 inhibited senescence and stemness induced by platinum-based chemotherapy in functional assays. Overall, these data establish that ALDH1A1 is essential for OCSCs survival and ALDH1A1 inhibition sup-presses chemotherapy induced senescence and stemness. Targeting ALDH1A1 using small molecule inhibitors in combination with chemotherapy therefore presents a promising strategy to pre-vent ovarian cancer recurrence and has potential for clinical translation.
REVIEW | doi:10.20944/preprints202202.0136.v1
Subject: Medicine And Pharmacology, Orthopedics And Sports Medicine Keywords: meta-analyses; primary knee osteoarthritis; stem cells; systematic review
Online: 9 February 2022 (10:57:45 CET)
Background: Conclusions of meta-analyses of clinical studies may substantially influence opinions of perspective patients and stakeholders in health care. Nineteen meta-analyses of clinical studies on the management of primary knee osteoarthritis (pkOA) with stem cells, published between January 2020 and July 2021, came to inconsistent conclusions regarding the efficacy of this treatment modality. It is possible that a separate meta-analysis based on an independent, systematic assessment of clinical studies on the management of pkOA with stem cells may reach a different conclusion. Methods: PubMed, Web of Science and the Cochrane library were systematically searched for clinical studies and meta-analyses of clinical studies on the management of pkOA with stem cells. All clinical studies and meta-analyses identified were evaluated in detail, as were all sub-analyses included in the meta-analyses. Results: The inconsistent conclusions regarding the efficacy of treating pkOA with stem cells in the 19 assessed meta-analyses were most probably based on substantial differences in literature search strategies among different authors, misconceptions about meta-analyses themselves, and misconceptions about the biology of stem cells. An independent, systematic review of the literature yielded a total of 183 studies, of which 33 were randomized clinical trials, including a total of 6860 patients with pkOA. However, it was not possible to perform a scientifically sound meta-analysis. Conclusion: Clinicians should interpret the results of the 19 assessed meta-analyses of clinical studies on the management of pkOA with stem cells with caution, and should be cautious of the conclusions drawn therein. Clinicians and researchers should strive to participate in FDA and/or EMA reviewed and approved clinical trials to provide clinically and statistically valid efficacy.
ARTICLE | doi:10.20944/preprints202111.0502.v1
Subject: Medicine And Pharmacology, Neuroscience And Neurology Keywords: Stem Cell; Embryo; Zebrafish; Neurosensory Hearing Loss; Tissue Regeneration
Online: 26 November 2021 (10:52:49 CET)
Hearing dysfunctions can be classified by type, degree, configuration, time of onset, aetiology, and finally, consequences on speech development. They can be divided into conductive, mixed, central types and sensorineural. Conductive hearing loss (CHL) results from interference with the mechanical transmission of sound through the external and middle ear; it can be congenital, as a consequence of anatomic abnormalities, but it can commonly be acquired following middle ear inflammatory pathologies. Sensorineural hearing loss (SNHL) results from failure to transduce vibrations to neural impulses in the cochlean and is a consequence of an irreversible damage to the differentiated cells which make up the organ of hearing and the acoustic paths at various levels. Mixed hearing loss involves a combination of these two types in the same ear. Studies in neuroscience field have shown that the prevention of cell degeneration is only possible if all the factors taken at the different stages of stem cells’ multiplication and differentiation are administered together. We have demonstrated this in a recent study on the ability of SCDSFs to prevent neurodegeneration in hippocampal cells of the CA1 zone in mice. This study confirms previous findings demonstrating that early developmental zebrafish embryo extracts could act as a modulator of senescence in human mesenchymal stem cells (hMSC) isolated from many adult tissues. These findings have open a promising way for the approaches promoting the rejuvenation and regeneration of different tissues, by-passing stem cell transplantation. In the present clinical trial we have used SCDSFs to study the possible reversion of neurosensory hearing loss, until now considered an irreversible condition.
REVIEW | doi:10.20944/preprints202109.0047.v2
Subject: Medicine And Pharmacology, Oncology And Oncogenics Keywords: Triple Negative Breast Cancer; Cancer Stem Cell; TGF-β
Online: 8 September 2021 (20:53:29 CEST)
Triple-negative breast cancer (TNBC) is a subtype of breast cancer that disproportionally accounts for the majority of breast cancer-related deaths due to the lack of specific targets for effective treatments. In this review, we highlight the complexity of the transforming growth factor-beta family (TGF-β) pathway and discuss how the dysregulation of the TGF-β pathway promotes oncogenic attributes in TNBC which negatively affects patient prognosis. Moreover, we discuss recent findings highlighting TGF-β inhibition as a potent method to target mesenchymal (CD44+/CD24-) and epithelial (ALDHhigh) cancer stem cell (CSC) populations. CSCs are associated with tumorigenesis, metastasis, relapse, resistance, and diminished patient prognosis; however, due to differential signal pathway enrichment and plasticity, these populations remain difficult to target and persist as a major barrier barring successful therapy. This review highlights the importance of TGF-β as a driver of chemoresistance, radioresistance and reduced patient prognosis in breast cancer and highlights novel treatment strategies which modulate TGF-β, impede cancer progression and reduce the rate of resistance generation via targeting the CSC populations in TNBC and thus reducing tumorigenicity. Potential TGF-β inhibitors targeting based on clinical trials are summarized for further investigation which may lead to the development of novel therapies to improve TNBC patient prognosis.
REVIEW | doi:10.20944/preprints202108.0044.v1
Subject: Biology And Life Sciences, Biochemistry And Molecular Biology Keywords: microgravity, stem cells, microphysiological systems, organoids, biofabrication, biomanufacturing, space
Online: 2 August 2021 (13:29:43 CEST)
In humankind’s endeavor to explore beyond our planet and travel further into space, we are now at the threshold of an era in which it is possible to move to and from low Earth orbit (LEO) with increasing ease and reduced cost. Through the International Space Station (ISS) U.S. National Laboratory, investigators from industry, academia, and government can easily access the unique LEO environment on the ISS to conduct research and development (R&D) activities in ways not possible on Earth. A key advantage of the LEO environment for life sciences research is the ability to conduct experiments in sustained microgravity conditions. The ability to conduct long-term research in microgravity enables opportunities for novel, fundamental studies in tissue engineering and regenerative medicine, including research on stem cell proliferation and differentiation, biofabrication, and disease modeling using microphysiological systems (MPS) that build on prior research using simulated microgravity conditions (Grimm, D., et al. 2018). Over the last decade, space-based research has demonstrated that microgravity informs our knowledge of fundamental biology and accelerates advancements in health care and medical technologies (International Space Station 2019). The benefits provided by conducting biomedical research in LEO may lead to breakthroughs not achievable on Earth. We are now at a transition point, in which nations are changing their approach to space-based R&D. The focus is shifting from government-funded fundamental science toward the expansion of privately funded R&D with terrestrial application and economic value that will drive a robust marketplace for innovation and manufacturing in LEO. Making this long-term transition requires public-private participation and near-term funding to support critical R&D to leverage the benefits of the LEO environment and de-risk space-based research. Studies conducted on the ISS over the past several years have indicated that one area with potential significant economic value and benefit to life on Earth is space-based biomanufacturing, or the use of biological and nonbiological materials to produce commercially relevant biomolecules and biomaterials for use in preclinical, clinical, and therapeutic applications. We must take advantage of the remaining lifetime of the ISS as a valuable LEO platform to demonstrate this economic value and Earth benefit. By facilitating access to the space station, the ISS National Lab is uniquely positioned to enable the R&D necessary to bridge the gap between the initial discovery phase of space-based biomedical research and the development of a sustainable, investment-worthy biomanufacturing market in LEO supported by future commercial platforms. Through a joint effort, the Center for the Advancement of Science in Space (CASIS), which manages the ISS National Lab, and the University of Pittsburgh’s McGowan Institute for Regenerative Medicine brought together thought leaders from around the U.S. for a Biomanufacturing in Space Symposium that consisted of a series of working sessions to review data from past space-based tissue engineering and regenerative medicine research, discuss relevant current space-based R&D in this area, and consider potential future markets to address the questions: What are the most promising opportunities to leverage the ISS to advance space-based biomanufacturing moving forward? What are the current gaps or barriers that, if overcome, could clear pathways toward private investment in LEO as a valued site for research, development, and production activity? And, most importantly: For which opportunities do the most compelling value propositions exist? The goal of the Biomanufacturing in Space Symposium was to help identify the specific areas in which government and industry investment would be most likely to stimulate advancements that overcome barriers. This would lead to a more investment-ready landscape for private interests to enter the market and fuel exponential growth. The symposium was meant to serve as the first step in developing a roadmap to a sustainable market for biomanufacturing in space. The symposium identified and prioritized multiple key R&D opportunities to advance space-based biomanufacturing. These opportunities fall in the areas of disease modeling, stem cells and stem-cell-derived products, and biofabrication. Additionally, symposium participants highlighted the critical need for additional data to help validate and de-risk these opportunities and concluded that approaches such as automation, artificial intelligence (AI), and machine learning will be needed to produce and capture the required data. Symposium participants also came to a consensus that public-private partnerships and funding will be needed to advance the opportunities toward a biomanufacturing marketplace in LEO. This paper will summarize the current state of the science and technology on the ISS and in the fields of tissue engineering and regenerative medicine; provide an overview of biomanufacturing R&D in space to date; review the goals of the Biomanufacturing in Space Symposium; highlight the key commercial opportunities and gaps identified during the symposium; provide information on potential market sizes; and briefly discuss the next steps in developing a roadmap to biomanufacturing in space.
REVIEW | doi:10.20944/preprints202103.0114.v1
Subject: Medicine And Pharmacology, Immunology And Allergy Keywords: organoid; stem cell; cancer; glioblastoma; glioma; oncology; precision medicine
Online: 2 March 2021 (21:59:47 CET)
The emergence of three-dimensional human organoids has opened the door for development of patient-derived cancer organoid (PDO) models, which closely recapitulate parental tumor tissue. Mainstays of preclinical cancer modeling include in vitro cell lines and patient-derived xenografts, but these models lack the cellular heterogeneity seen in human tumors. Moreover, xenograft establishment is resource- and time-intensive, rendering these models difficult to use to inform clinical trials and decisions. PDOs, however, can be created efficiently and retain tumor-specific properties such as cellular heterogeneity, cell-cell and cell-stromal interactions, tumor microenvironment, and therapeutic responsiveness. PDO models and drug screening protocols have been described for several solid tumors and, more recently, for gliomas. Since PDOs can be developed in clinically relevant timeframes and share many characteristics of parent tumors, they may enhance the ability to provide precision oncologic care for patients. This review explores the current literature on cancer organoids, highlighting the history of PDO development, organoid models of glioma, and potential clinical applications of PDOs.
REVIEW | doi:10.20944/preprints202101.0307.v1
Subject: Biology And Life Sciences, Biochemistry And Molecular Biology Keywords: gametogenesis; oocytes; pathways; signaling; stem cells; differentiation; tumor; cancer
Online: 18 January 2021 (09:14:54 CET)
In the present era, infertility is one of the major issues which restricts many couples to have their own kids. Infertility is the inability to achieve a clinical pregnancy after regular unprotected sexual intercourse for the period of one year or more. Various factors including defective male or female germ cell development, unhealthy and improper lifestyles, diseases like cancer and associated chemo-or-radiation therapies, congenital disorders etc. may be responsible for infertility. Therefore, it is highly important to understand the basic concepts of germ cell development including primordial germ cell (PGC) formation, specification, migration, entry to genital ridges and their molecular mechanisms, activated pathways, paracrine and autocrine signaling, along with possible alteration which can hamper germ cell development and can cause adversities like cancer progression and infertility. Knowing all these aspects in a proper way can be very much helpful in improving our understanding about gametogenesis and finding possible ways to cure related disorders. Here in this review, various aspects of gametogenesis especially female gametes and relevant factors causing functional impairment have been thoroughly discussed.
Subject: Medicine And Pharmacology, Immunology And Allergy Keywords: Mutation; Epigenetic; Genetic; Neoplastic transformation; Stem cell; Tumor classification
Online: 30 November 2020 (08:26:34 CET)
There are many theories of carcinogenesis arguing against the orthodox mutation theory, debating on such as “epigenetic alteration” that is inheritable and yet, theoretically, reversible. Our integrated theory describes that any extracellular, intracellular, or intranuclear stressors, mutagenic or not, can initiate a lengthy tumorigenesis to engender a benign or malignant tumor, but the aberrations directly establishing cellular immortality and autonomy may be epigenetic or genetic alterations in the genomic DNA. A neoplasm is considered a semi-new organism with autonomy; it therefore should have genetic mutations to be “new”. We may be able to direct cancer cells towards differentiation as a remedy, because the extracellular milieu may control the phenotype of a cell and the tissue or organ made of the cell’s progenies, and the cytoplasm of a cell may override the nucleus in the phenotypic control. However, the nucleus retains the capacity to manifest itself if allowed by the microenvironment, which then allows the already reversed cells to revert back to tumor cells again. Neoplasms are malignant if they bear epigenetic or genetic anomalies in mutator genes defined as those whose alterations allow or accelerate alterations to occur in other genes, whereas neoplasms are benign if they bear epigenetic or genetic aberrations only in non-mutator genes. It is imperative to identify the immediate tumor-causing cellular alterations defined as those directly responsible for immortality and autonomy, and for treatment purposes to identify the extracellular and intracellular factors that control the phenotype of cancer cells.
ARTICLE | doi:10.20944/preprints202010.0107.v1
Subject: Biology And Life Sciences, Biochemistry And Molecular Biology Keywords: Bioprinting; microextrusion; tissue engineering; bioink; open-source; stem cells
Online: 6 October 2020 (08:24:54 CEST)
Three-dimensional (3D) bioprinting promises to be essential in tissue engineering for solving the rising demand for organs and tissues. Some bioprinters are commercially available, but their impact on the field of TE is still limited due to their cost or difficulty to tune. Herein, we present a low-cost easy-to-build printhead for microextrusion-based bioprinting (MEBB) that can be installed in many desktop 3D printers to transform them into 3D bioprinters. We can extrude bioinks with precise control of print temperature between 2 - 60 ºC. We validated the versatility of the printhead, by assembling it in three low-cost open-source desktop 3D printers. Multiple units of the printhead can also be easily put together in a single printer carriage for building a multi-material 3D bioprinter. Print resolution was evaluated by creating representative calibration models at different temperatures using natural hydrogels such as gelatin and alginate, and synthetic ones like poloxamer. Using one of the three modified low-cost 3D printers, we successfully printed cell-laden lattice constructs with cell viabilities higher than 90% after 24h post printing. Controlling temperature and pressure according to the rheological properties of the bioinks was essential in achieving optimal printability and great cell viability. The cost per unit of our device, which can be used with syringes of different volume, is less expensive than any other commercially available product. These data demonstrate an affordable open-source printhead with the potential to become a reliable alternative to commercial bioprinters for any laboratory.
REVIEW | doi:10.20944/preprints202004.0479.v1
Subject: Biology And Life Sciences, Cell And Developmental Biology Keywords: Stem cells banks; Cancer; Cytosine deaminase; Tumor; Gene therapy
Online: 27 April 2020 (04:49:54 CEST)
Stem cells are currently being used in many clinical trials for regenerative purposes. These are promising results for stem cells in the treatment of several diseases, including cancer. Nevertheless, there are still many variables which should be addressed before the application of stem cells for cancer treatment. One approach should be to establish well-characterized therapeutic stem cell banks to minimize the variation in results from different clinical trials and facilitate their effective use in basic and translational research.
REVIEW | doi:10.20944/preprints201912.0388.v1
Subject: Biology And Life Sciences, Cell And Developmental Biology Keywords: cancer stem cells; plasticity; Epithelial-Mesenchymal Transition; metastasis; microenvironment
Online: 29 December 2019 (14:51:39 CET)
Intratumoral heterogeneity is a major ongoing challenge in the effective therapeutic targeting of cancer. Accumulating evidence suggests that a fraction of cells within a tumor termed Cancer Stem Cells (CSCs) are primarily responsible for this diversity resulting in therapeutic resistance and metastasis. Adding to this complexity, recent studies have shown that there can be different subpopulations of CSCs with varying biochemical and biophysical traits resulting in varied dissemination and drug-resistance potential. Moreover, cancer cells can exhibit a high level of plasticity or the ability to dynamically switch between CSC and non-CSC states or among different subsets of CSCs. The molecular mechanisms underlying such plasticity has been under extensive investigation and the trans-differentiation process of Epithelial to Mesenchymal transition (EMT) has been identified as a major contributing factor. Besides genetic and epigenetic factors, CSC plasticity is also shaped by non-cell-autonomous effects such as the tumor microenvironment. In this review, we discuss the recent developments in understanding CSC plasticity in tumor progression at biochemical and biophysical levels, and the latest in silico approaches being taken for characterizing cancer cell plasticity with implications in improving existing therapeutic approaches.
CASE REPORT | doi:10.20944/preprints201912.0185.v2
Subject: Biology And Life Sciences, Cell And Developmental Biology Keywords: Eye; Corneal ulcer; Canine; Mesenchymal stem cell; Cell Therapy
Online: 16 December 2019 (11:32:08 CET)
Corneal ulcer (CU) is an ophthalmopathy characterized by depression of the corneal surface with at least one stromal loss. CU is common in canine and feline species and is usually caused, among others, by trauma, infections, toxic contamination and endocrine disorders. They usually result from an increased inflammatory response and are associated with some clinical signs such as blepharospasm, photophobia, epiphora, pain and loss of corneal transparency. Despite advances in conventional and pharmacological therapy, in many cases indolent and recurrent ulcer treatments still lead to loss of visual acuity of the animal. This paper aims to report the effect of topical application of canine adipose tissue-derived mesenchymal stem cell (cATMSCs) as treatment of recurrent CU in a Poodle dog breed that showed clear difficulty in the healing process associated with diabetes. The animal was submitted to two applications of cATMSCs and showed improvement in the blepharospasm, conjunctival hyperemia, mucopurulent ocular secretion, photophobia, corneal opacity, chemosis, pigmentation, neovascularization, and pain parameters. Besides, Fluorescein test, Schirmer test and ocular fundus exam also showed improvement in their values concomitantly with lesion resolution. Due this, we showed that cATMSC therapy contribute to the regeneration of corneal tissue in CU and may contribute to the treatment to others ophthalmopathies.
ARTICLE | doi:10.20944/preprints201911.0395.v1
Subject: Biology And Life Sciences, Cell And Developmental Biology Keywords: cardiac hypertrophy; cardiomyocytes; disease model; endothelin-1; stem cells
Online: 30 November 2019 (12:38:21 CET)
Cardiac hypertrophy is an important and independent risk factor for the development of heart failure. To better understand the mechanisms and regulatory pathways involved in cardiac hypertrophy, there is a need for improved in vitro models. In this study, we investigated how hypertrophic stimulation affected human induced pluripotent stem cell (iPSC)-derived cardiomyocytes (CMs). The cells were stimulated with endothelin-1 (ET-1) for 8, 24, 48, 72, or 96h. Parameters including cell size, ANP-, proBNP-, and lactate concentration were analyzed. Moreover, transcriptional profiling using RNA-sequencing was performed to identify differentially expressed genes following ET-1 stimulation. The results show that the CMs increase in size by approximately 13% when exposed to ET-1 in parallel to increases in ANP and proBNP protein and mRNA levels. Furthermore, the lactate concentration in the media was significantly increased indicating that the CMs consume more glucose, a hallmark of cardiac hypertrophy. Using RNA-seq, a hypertrophic gene expression pattern was also observed in the stimulated CMs. Taken together, these results show that hiPSC-derived CMs stimulated with ET-1 display a hypertrophic response. The results from this study also provide new molecular insights about the underlying mechanisms of cardiac hypertrophy and may help accelerate the development of new drugs against this condition.
REVIEW | doi:10.20944/preprints201909.0327.v1
Subject: Medicine And Pharmacology, Oncology And Oncogenics Keywords: glioblastoma; renin-angiotensin system; cancer stem cells; drug repurposing
Online: 29 September 2019 (06:21:26 CEST)
Patients with glioblastoma (GB), a highly aggressive brain tumor, have a median survival of 14.6 months following neurosurgical resection with adjuvant chemoradiotherapy. Quiescent GB cancer stem cells (CSCs) invariably cause local recurrence. These GB CSCs that can be identified by embryonic stem cell markers express components of the renin-angiotensin system and are associated with circulating CSCs. Despite the presence of circulating CSCs, GB rarely develops distant metastasis outside the central nervous system. This paper reviews the current literature on GB growth inhibition in relation to CSCs, circulating CSCs, the RAS and the novel therapeutic approach by repurposing drugs that target the renin-angiotensin system to improve overall symptom-free survival and maintain quality of life.
ARTICLE | doi:10.20944/preprints201906.0045.v1
Subject: Medicine And Pharmacology, Gastroenterology And Hepatology Keywords: Cirrhosis; Bone marrow; Mesenchymal stem cells; Characteristics; Liver regeneration
Online: 5 June 2019 (15:43:03 CEST)
Liver cirrhosis leads to hepatic dysfunction and life-threatening conditions. Though clinical efficacy of autologous bone marrow-drived mesenchymal stem cells (BM-MSC) transplantation in alcoholic cirrhosis (AC) was demonstrated, the relevant mechanism has not been elucidated. We aimed to identify predictive factors and gene/pathways for responders after autologous BM-MSC transplantation. Fifty-five patients with biopsy-proven AC underwent autologous BM-MSC transplantation. The characteristics of responders who showed improvement in fibrosis score (≥ 1) after transplantation were compared with those of non-responders. BM-MSCs were analyzed with cDNA microarrays to identify genes and pathways that were differentially expressed in responder after transplantation. Thirty-three patients (66%) were responders. In the multivariate analysis, initial high Laennec score (p=0.007, odds ratio 3.73) and performance of BM-MSC transplantation (p=0.033, odds ratio 5.75) were predictive factors for responder. Three genes (olfactory receptor 2L8, microRNA4520-2, and chloride intracellular channel protein 3) were upregulated in responders and 11 metabolic pathways (inositol phosphate, ATP-binding cassette transporters, protein kinase signaling, extracellular matrix-receptor interaction, endocytosis, phagosome, hematopoietic cell lineage, adipocytokine, peroxisome proliferator-activated receptor, fat digestion/absorption, and insulin resistance) were upregulated in non-responders (p<0.05). BM-MSC transplantation is warranted treatment for AC patients with high Laennec score. Cell-based therapy utilizing response-relating genes or pathway can be treatment candidate.
REVIEW | doi:10.20944/preprints201905.0101.v1
Subject: Biology And Life Sciences, Cell And Developmental Biology Keywords: Transgenic; Cancer; Carcinogenesis; Immortality; Autonomy; cancer stem cells; senescence
Online: 9 May 2019 (11:29:34 CEST)
Modern research into carcinogenesis has undergone three phases. Surgeons and pathologists started the first phase and established autopsy and biopsy as routine pathology services, in turn establishing morphological traits for tumors and establishing immortality and autonomy as indispensable criteria for neoplasms. A century ago medical doctors and biologists initiated “experimental cancer research” as the second phase, in which they, with help from chemists, established many chemical-induced animal models of carcinogenesis. In this phase, the two-hit theory and stepwise carcinogenesis of “initiation-promotion” or “initiation-promotion-progression” were established, with an illustrious finding that outgrowths induced in animals depend on the inducers, and thus are not authentically neoplastic, until late stages. For the last 40 years, molecular biologists have gradually dominated the carcinogenesis research fraternity and have established numerous genetically-modified animal models of carcinogenesis. However, evidence has not been provided for immortality and autonomy of the lesions from most of these models. Probably, many peers had already collected the lesions from animals for analyses of “cancer” mechanisms before the lesions became autonomous. We herein review monumental work of many predecessors to reinforce that evidence for immortality and autonomy is essential for confirming a neoplastic nature. We extrapolate that immortality and autonomy are established early during sporadic human carcinogenesis, unlike the late establishment in all animal models. It is imperative to resume many forerunners’ work by determining the genetic bases for initiation, promotion and progression, the genetic bases for immortality and autonomy, and which animal models are, in fact, good for identifying such genetic bases.
ARTICLE | doi:10.20944/preprints201811.0376.v1
Subject: Computer Science And Mathematics, Applied Mathematics Keywords: bone repair; macrophages; immune system; cytokines; mesenchymal stem cells
Online: 16 November 2018 (06:42:10 CET)
A new mathematical model is presented to study the effects of macrophages on the bone fracture healing process. The model consists of a system of nonlinear ordinary differential equations that represents the interactions among classically and alternatively activated macrophages, mesenchymal stem cells, osteoblasts, and pro- and anti-inflammatory cytokines. A qualitative analysis of the model is performed to determine the equilibria and their corresponding stability properties. Numerical simulations are also presented to support the theoretical results and to monitor the evolution of a broken bone for different types of fractures under various medical interventions. The model can be used to guide clinical experiments and to explore possible medical treatments that accelerate the bone fracture healing process either by surgical interventions or drug administrations.
ARTICLE | doi:10.20944/preprints201810.0719.v1
Subject: Biology And Life Sciences, Biochemistry And Molecular Biology Keywords: beta-lapachone; Breast cancer stem cell; DLGAP5; Mammosphere; NQO1
Online: 30 October 2018 (09:14:35 CET)
Background: Cancer stem cells (CSCs) exhibit self-renewal activity and give rise to other cell types in tumors. Due to the infinite proliferative potential of CSCs, drugs targeting these cells are necessary to completely inhibit cancer development. beta-lapachone (bL) has been widely used to treat cancer development, but its effect on cancer stem cells remain elusive. Thus, we investigated the effect of bL on mammosphere formation using breast cancer stem cell (BCSC) marker positive cells, MDA-MB-231. Methods: MDA-MB-231 Cells, which is negative for NQO1 expression, was constructed to stably express NQO1(NQO1 stable cells) to see the effect of bL. The effect of bL on cells were evaluated by wound healing and Transwell cell culture chambers, and ALDEFLUOR assay. Results: Here, we show that bL inhibited the proliferative ability of mammosphere derived from BCSC marker-positive cells, MDA-MB-231, in an NQO1-dependent manner. bL treatment efficiently downregulated expression level of BCSC markers CD44, ALDH1A1, and DLGAP5 that recently identified as a stem cell proliferation marker in both cultured cells and mammosphered cells. Moreover, bL efficiently downregulates cell proliferation and migration activities. Conclusions: These results strongly suggest that bL could be a therapeutic agent targeting breast cancer stem cells with proper NQO1 expression.
REVIEW | doi:10.20944/preprints201809.0392.v1
Subject: Biology And Life Sciences, Cell And Developmental Biology Keywords: H2O2, redox signalling, development, regeneration, adult stem cells, metazoan
Online: 19 September 2018 (21:42:44 CEST)
Reactive oxygen species (ROS), which were originally classified as exclusively deleterious compounds, have gained increasing interest in the recent years given their action as bona fide signalling molecules. The main target of ROS action is the reversible oxidation of cysteines, leading to the formation of disulfide bonds, which modulate protein conformation and activity. ROS endowed with signalling properties are mainly produced by NADPH oxidases at the plasma membrane, but their action also involves a complex machinery of multiple redox-sensitive protein families that differs in their subcellular localization and their activity. Given that the levels and distribution of ROS are highly dynamic in part due to their limited stability, the development of various fluorescent ROS sensors, some of which are quantitative (ratiometric), represents a clear breakthrough in the field and have been adapted to both ex vivo and in vivo applications. The physiological implication of ROS signalling will be presented mainly in the frame of morphogenetics processes, embryogenesis, regeneration, and stem cell differentiation. Gain and loss of function as well as pharmacological strategies have demonstrated the wide but specific requirement of ROS signalling at multiple stages of these processes and its intricate relationship with other well-known signalling pathways.
ARTICLE | doi:10.20944/preprints201808.0035.v1
Subject: Biology And Life Sciences, Animal Science, Veterinary Science And Zoology Keywords: neural; stem cells; compressed; spinal cord; injury; regeneration; rat
Online: 2 August 2018 (06:26:46 CEST)
Background: In spinal cord injury, radical treatment is still a persistent hope for patients and clinicians. Our study aimed to determine the different histological changes in central, cranial and caudal sites of compressed spinal cord as a result of neuroectodermal stem cells (NESCs) transplantation in rats. Material and methods: For extraction of NESCs, future brains were extracted from mice embryos (10-days old) and cultured. Eighty, male rats were divided randomly into control, sham (20 rats each); while 40 rats were subjected to compressed spinal cord injury (CSCI). Seven days after spinal cord injury, rats were subdivided into 2 groups (20 rats each); an untreated and treated with NESCs injected cranial and caudal to the site of the spinal cord injury. Rats were sacrificed 4 weeks after transplantations of NESCs and specimens from the spinal cord at the central, cranial and caudal to site of spinal cord injury were proceeded to be stained with haematoxylin & eosin, osmic acid and Immunohistochemistry of glial fibrillary acidic protein (GFAP). Results: Sections of CSCI revealed areas of hemorrhages, necrosis and cavitation limited by reactive astrocytosis, with upregulation of GFAP expression. Evidence of remyelination and mitigation of histopathological features, reactive astrocytosis in CSCI sections were more pronounced in cranial than in caudal region. Conclusions: NESCs transplantation ameliorated the pathological changes, promoted remyelination.
ARTICLE | doi:10.20944/preprints202305.2155.v1
Subject: Biology And Life Sciences, Cell And Developmental Biology Keywords: drug toxicity; budesonide analogues; stem cells; pluripotency exit; 3D gastruloids
Online: 30 May 2023 (13:48:16 CEST)
Small molecules that can modulate or stabilize cell-cell interactions are valuable tools for investigating the impact of collective cell behavior on various biological processes such as development/morphogenesis, tissue regeneration and cancer progression. Recently, we showed that budesonide, a glucocorticoid widely used as anti-asthmatic drug, is a potent regulator of stem cell pluripotency. Here we tested the effect of different budesonide derivatives and identified CHD-030498 as a more effective analogue of budesonide. CHD-030498 was able to prevent stem cell pluripotency exit in different cell-based models, including embryonic stem-to-mesenchymal transition, spontaneous differentiation and 3D gastruloid development, and at lower doses compared to budesonide.
ARTICLE | doi:10.20944/preprints202304.0758.v1
Subject: Biology And Life Sciences, Biology And Biotechnology Keywords: marigold; callus; cell suspension; growth parameters; cell viability; stem cell
Online: 23 April 2023 (04:05:25 CEST)
Plant stem cell cultures have so far been established in only a few plant species using cambial meristematic cells. The presence of stem cells or stem cell-like cells in other organs and tissues of the plant body, as well as the possibility of de novo generation of meristematic cells from differentiated cells, allows to consider the establishment of stem cell cultures in a broader range of species. Therefore, this study aimed to establish a stem cell culture of the medicinal plant Calendula officinalis L. Callus tissues were induced from explants taken from leaves and roots. Appropriate combinations of plant growth regulators and light parameters for in vitro cultivation were selected. Already at this stage, stem and dedifferentiated cells could be identified, and cell suspension cultures were established from specific parts of the formed callus. Cell suspension cultures with a high proportion of stem cells originating from roots (92–93%) or leaves (72–73%) were developed. The amount of stem cells derived from the roots in the cell suspension reached a plateau at a level of 5.60–5.72105.
ARTICLE | doi:10.20944/preprints202304.0174.v1
Subject: Chemistry And Materials Science, Surfaces, Coatings And Films Keywords: Ti2AlC; YSZ TBC; Al2O3 TGO; burner oxidation; FIB TEM/STEM
Online: 11 April 2023 (02:48:43 CEST)
A FIB/STEM interfacial study was performed on a TBC/Ti2AlC MAX phase system, oxidized in an aggressive burner rig test (Mach 0.3 at 1300°C for 500 h). The 7YSZ TBC, a-Al2O3 TGO, and MAXthal 211 Ti2AlC base were variously characterized by TEM/STEM, EDS, SADP, and HRTEM. The YSZ was a mix of ‘clean’ featureless and ‘faulted’ high contrast grains. The latter exhibited ferro-elastic domains of high Y content tetragonal t'' variants. No martensite was observed. The TGO was essentially a duplex a-Al2O3 structure of inner columnar plus outer equiaxed grains. It maintained a perfectly intact, clean interface with the Ti2AlC substrate. The Ti2AlC substrate exhibited no interfacial Al-depletion zone, but rather numerous faults along the basal plane of the hexagonal structure. These are believed to offer a means of depleting Al by forming crystallographic, low-Al planar defects, proposed as Ti2.5AlC1.5. These characterizations support and augment prior optical, SEM, and XRD findings that demonstrated remarkable durability for the YSZ/Ti2AlC MAX phase system in aggressive burner tests.
CASE REPORT | doi:10.20944/preprints202303.0306.v1
Subject: Medicine And Pharmacology, Clinical Medicine Keywords: acute lymphoblastic leukemia; Philadelphia chromosome; relapse; allogeneic stem cell transplantation
Online: 16 March 2023 (11:33:44 CET)
Relapsed acute lymphoblastic leukemia (ALL) represents a continuous challenge for the clinician. Despite recent advances in treatment, the risk of relapse remains significant. The clinical, biological, cytogenetic, and molecular characteristics may be different at the time of relapse. Current comprehensive genome sequencing studies suggest that most relapsed patients, especially those with late relapses, acquire new genetic abnormalities, usually within a minor clone that emerges after ALL diagnosis. We report the case of a 23-year-old young woman diagnosed with Philadelphia chromosome negative B-cell acute lymphoblastic leukemia. The patient underwent allogeneic stem cell transplantation (allo-HSCT) after complete remission. Although having favorable prognostic factors at diagnosis, the disease relapsed early after allo-HSCT. The cytogenetic and molecular exam at relapse was positive for the Philadelphia chromosome, respectively for the bcr-abl transcript. What exactly led to the relapse of this disease in a more aggressive cytogenetic and molecular form, although there were no predictive elements in the diagnosis of this relapse?
ARTICLE | doi:10.20944/preprints202301.0159.v1
Subject: Biology And Life Sciences, Cell And Developmental Biology Keywords: mesenchymal stem cells; mechanotransduction; collagen; oxidation; YAP/TAZ; focal adhesion
Online: 9 January 2023 (09:53:23 CET)
ECM provides various mechanical cues that are able to affect the self‑renewal and differentiation of mesenchymal stem cells (MSC). Little is known however how these ques work in a pathological environment, such as acute oxidative stress. To better understand the behavior of human adipose tissue-derived MSC (ADMSC) in such conditions here we provide morphological and quantitative evidence for significantly altered early steps of mechanotransduction when adhering to oxidized collagen (Col-Oxi). This affects both focal adhesion (FA) formation and YAP/TAZ signaling events. Representative morphological images show that ADMSCs spread better within 2 h of adhesion on native collagen (Col), while they tended to round up on Col-Oxi. It correlates also with the less development of the actin cytoskeleton and FA formation, confirmed quantitatively by morpho-metric analysis using ImageJ. As shown by immunofluorescence analysis, oxidation also affected the ratio of cytosolic to nuclear YAP/TAZ activity, concentrating in the nucleus for Col while remaining in the cytosol for Col-Oxi, suggesting abrogated signal transduction. Comparative AFM studies show that native collagen forms relatively coarse aggregates, much thinner with Col-Oxi, possibly reflecting its altered ability to aggregate. On the other hand, the corresponding Young's moduli were only slightly changed, so viscoelastic properties cannot explain the observed biological differences. However, the roughness of the protein layer decreases dramatically, from RRMS equal to 27.95 + 5.1 nm for Col to 5.51 + 0.8 nm for Col-Oxi (p<0.05), which dictates our conclusion that it is the most altered parameter in oxidation. Thus, it appears to be a predominantly topo-graphic response that affects the mechanotransduction of ADMSCs by oxidized collagen.
REVIEW | doi:10.20944/preprints202207.0219.v1
Subject: Medicine And Pharmacology, Psychiatry And Mental Health Keywords: personalized psychiatry; psychiatric disorders; induced pluripotent stem cells; brain organoids
Online: 14 July 2022 (11:46:51 CEST)
The polygenic and multifactorial nature of many psychiatric disorders has hampered the personalized medicine approach implementation in clinical practice. However, induced pluripotent stem cell (iPSC) technology has emerged as an innovative tool for patient-specific disease modeling to expand the pathophysiology knowledge and treatment perspectives in the last decade. Current technologies enable adult human somatic cell reprogramming into induced pluripotent stem cells (iPSCs) to generate neural cells and direct neural cell conversion to model organisms that exhibit phenotypes close to human diseases, thereby effectively representing relevant aspects of neuropsychiatric disorders. iPSCs reflect patient pathophysiology and pharmacological responsiveness, particularly when cultured under conditions that recapitulate spatial tissue organization in brain organoids. Recently, the application of iPSCs has been frequently associated with gene editing that targets the disease-causing gene to deepen the illness pathophysiology and conduct drug screening. Moreover, gene editing has provided a unique opportunity to repair the putative causative genetic lesions in patient-derived cells. Here, we review the use of iPSC technology to model and potentially treat neuropsychiatric disorders by illustrating the key studies on a series of mental disorders, including schizophrenia, major depression disorder, bipolar disorder, and autism spectrum disorder. The future perspective will involve the development of organ-on-a-chip platforms that control the microenvironmental conditions to reflect individual pathophysiological by adjusting physiochemical parameters according to personal health data. This strategy could open new ways to build a disease model that considers individual variability and tailors personalized treatments.
ARTICLE | doi:10.20944/preprints202207.0167.v1
Subject: Biology And Life Sciences, Cell And Developmental Biology Keywords: European mink; ex situ conservation; biobank; mesenchymal stem/stromal cells
Online: 12 July 2022 (04:04:08 CEST)
The European mink (Mustela lutreola) is one of Europe's most endangered species, and it is on the brink of extinction in the Iberian Peninsula. The species' precarious situation requires the application of new ex-situ conservation methodologies that complement the existing ex-situ and in-situ conservation measures. Here, we report for the first time the establishment of a biobank of European mink mesenchymal stem cells (emMSC) and oocytes from specimens found dead in the Iberian Peninsula, either free or in captivity. New emMSC lines were isolated from different tissues: bone marrow (emBM-MSC), oral mucosa (emOM-MSc), dermal skin (emDS-MSC), oviduct (emO-MSc), endometrium (emE-MSC), testicular (emT-MSC), and adipose tissue from two different adipose depots: subcutaneous (emSCA-MSC) and ovarian (emOA-MSC). All the eight emMSC lines showed plastic adhesion, detectable expression of characteristic markers of MSCs and, when cultured under osteogenic and adipogenic conditions, differentiation capacity to these lineages. Additionally, we were able to keep 227 Cumulus-oocyte complexes (COCs) in the biobank, 97 of which are grade I or II. The European mink MSC and oocyte biobank will allow for the conservation of the species' genetic variability, the application of assisted reproduction techniques, and the development of in vitro models for studying the molecular mechanisms of infectious diseases that threaten the species' precarious situation.
ARTICLE | doi:10.20944/preprints202207.0098.v1
Subject: Medicine And Pharmacology, Otolaryngology Keywords: tinnitus; normal hearing; Evoked potentials; auditory; brain stem; otoacoustic emission
Online: 6 July 2022 (13:54:44 CEST)
In patients with unilateral tinnitus with normal hearing, several studies have compared the ipsilateral and contralateral ears; however, few studies have investigated its relationship with the duration of tinnitus. We compared the auditory brainstem response and otoacoustic emission parameters between ipsilateral and contralateral ears in adults with unilateral tinnitus and normal hearing. This retrospective review included 84 patients with unilateral tinnitus and normal hearing who underwent auditory brainstem response and otoacoustic emission; they were categorized according to the duration of tinnitus. The latencies and amplitudes of waves I, III, and V, and V/I ratio of both ears in auditory brainstem response, and the results of distortion-product otoacoustic emission and transient evoked otoacoustic emission were examined. The auditory brainstem response parameters, distortion-product otoacoustic emission parameters, and transient evoked otoacoustic emission parameters between the ipsilateral and contralateral ears along the duration of tinnitus were analyzed. Moreover, the failure rates of both distortion-product otoacoustic emission and transient evoked otoacoustic emission between the ears along with the duration and the effects of the variables on the amplitude and latency of each wave were examined. Although there was little significant difference between the ipsilateral and contralateral ears, laterality seemed to have an effect on wave I latency in the multiple linear regression analysis. The distortion-product otoacoustic emission failure rate of the ipsilateral ear was higher than that of the contralateral ear in all patients. However, there was no remarkable difference between the ears in the distortion-product otoacoustic emission and transient evoked otoacoustic emission parameters throughout the duration. We found that outer hair cells and the distal portion of the cochlear nerve are possible pathologic lesions in tinnitus with normal hearing and cochlear synaptopathy could be suspected. Further studies, including those on inner hair cells and higher central cortex, are needed.
Subject: Biology And Life Sciences, Cell And Developmental Biology Keywords: Neural Stem Cell; Secretome; Neurodevelopment; Radial Glia; Neural Progenitor Cell
Online: 4 October 2021 (12:25:30 CEST)
Neural stem cell (NSC) based therapies are at the forefront of regenerative medicine strategies to combat illness and injury of the central nervous system (CNS). In addition to their ability to produce new cells, NSCs secrete a variety of products, known as the NSC secretome, that have been shown to ameliorate CNS disease pathology and promote recovery. As pre-clinical and clinical research to harness the NSC secretome for therapeutic purposes advances, a more thorough understanding of the endogenous NSC secretome can provide useful insight into the functional capabilities of NSCs. In this review, we focus on research investigating the autocrine and paracrine functions of the endogenous NSC secretome across life. We also compare the NSC secretome across species, finding signs of conserved parallels between rodent, human and zebrafish NSC secretomes. Throughout development and adulthood, we find evidence that the NSC secretome is a critical component of how endogenous NSCs regulate themselves and their niche. We also find gaps in current literature, most notably in the clinically relevant domain of endogenous NSC paracrine function in the injured CNS. Future investigations to further define the endogenous NSC secretome and its role in CNS tissue regulation are necessary to bolster our understanding of NSC-niche interactions and to aid in the generation of safe and effective NSC-based therapies.