ARTICLE | doi:10.20944/preprints201809.0024.v1
Subject: Earth Sciences, Other Keywords: oral mucositis; glycine; intercellular signaling peptides and proteins
Online: 3 September 2018 (11:09:30 CEST)
Oral mucositis is most frequently a toxic effect of chemotherapeutic and/or radiotherapeutic treatment, resulting from complex multifaceted biological events involving DNA damage. The clinical manifestations have a negative impact on the life quality of cancer patients. Preventive measures and curative treatment of mucositis are still not well established. The glycine has anti-inflammatory, immunomodulatory and cytoprotective actions, being a potential therapeutic in mucositis. The objective was to evaluate the effects of glycine on the expression of collagen and growth factors, platelet and epidermal in oral mucositis. The mucositis of which was induced by the protocol of Sonis. 40 hamsters were used, divided into two groups: Group I- control; Group II- supplemented with 5% intraperitoneal glycine, 2,0 mg/g diluted in hepes. Histopathological sections were used to perform the immune-histochemical method, the evaluation collagen expression and the growth factors: EGF and PDGF. It was observed that the group supplemented with glycine higher amounts of collagen expression and predominance type of collagen I. The glycine group presented lower immunoexpression of the growth factors, EGF and PDGF. The group supplemented with glycine showed a marked healing process of the oral mucosite, demonstrated by the predominance of collagen type I and reduction of growth factors, EGF and PDGF.
REVIEW | doi:10.20944/preprints202208.0145.v1
Subject: Life Sciences, Microbiology Keywords: Leishmania; co-infections; mixed infections; co-culture; hybrid; intercellular communication
Online: 8 August 2022 (10:20:49 CEST)
Leishmania parasites present astonishing adaptative abilities that represent a matter of life or death within disparate environments during the heteroxenous parasite life cycle. From an evolutionary perspective, organisms develop methods of overcoming such challenges. Strategies that extend beyond the genetic diversity have been discussed and include variability between parasite cells during the infections of their hosts. The occurrence of Leishmania subpopulation fluctuations with variable structural genomic contents demonstrates that a single strain might shelter the variability required to overcome inconsistent environments. Such intrastrain variability provides parasites with an extraordinary ability to adapt and thus survive and propagate. However, different perspectives on this evolution have been proposed. Strains or species living in the same environment can cooperate but also compete. These interactions might increase the replication rate of some parasites but cause the loss of more aggressive competitors for others. Adaptive responses to intra- and interspecific competition can evolve as a fixed strategy (replication is adapted to the average genetic complexity of infections) or an optional strategy (replication varies according to the genetic complexity of the current infection). This review highlights the complexity of interspecies and intrastrain interactions among Leishmania parasites as well as the different factors that influence this interplay.
REVIEW | doi:10.20944/preprints202105.0137.v1
Subject: Life Sciences, Other Keywords: cAMP; beta cells; stimulus-secretion coupling; intercellular coupling; PKA; Epac2A
Online: 7 May 2021 (09:52:15 CEST)
Pancreatic beta cells secrete insulin in response to stimulation with glucose and other nutrients, and impaired insulin secretion plays a central role in development of diabetes mellitus. Pharmacological management of diabetes includes various antidiabetic drugs, including incretins. The incretin hormones, glucagon-like peptide-1 and gastric inhibitory polypeptide, potentiate glucose-stimulated insulin secretion by binding to G protein-coupled receptors, resulting in stimulation of adenylate cyclase and production of the secondary messenger cAMP, which exerts its intracellular effects through activation of protein kinase A or the guanine nucleotide exchange protein 2A. The mo-lecular mechanisms behind these two downstream signaling arms are still not fully elucidated and involve many steps in the stimulus-secretion coupling cascade, ranging from the proximal regula-tion of ion channel activity, to the central Ca2+ signal, and the most distal exocytosis. In addition to modifying intracellular coupling, the effect of cAMP on insulin secretion could also be at least partly explained by the impact on intercellular coupling. In this review, we systematically describe the possible roles of cAMP at these intra- and inter-cellular signaling nodes, keeping in mind the rele-vance for the whole organism and translation to humans.
REVIEW | doi:10.20944/preprints202105.0754.v1
Subject: Life Sciences, Biochemistry Keywords: Exosome isolation and characterization; Exosomal research guidelines; Intercellular communication and host manipulation; Leishmania extracellular vesicles cargo; Leishmaniases.
Online: 31 May 2021 (11:43:19 CEST)
Leishmania parasites are a group of kinetoplastid pathogens that cause a variety of clinical forms while maintaining cell communication by secreting extracellular vesicles. Emerging technologies have been adapted for the studies of Leishmania-host-cell interactions to enable broad scale analysis of parasite extracellular vesicles. Leishmania extracellular vesicles (LEVS) are naturally released spheroidal nanoparticles of polydispersed suspensions surrounded by a lipid layer of membrane. Although LEVs have increasingly gained in importance, much is still unexplained, including bioavailability and function in the complex molecular mechanisms of pathogenesis. Considering the importance of LEVs in the parasite-host interaction and in the parasite-parasite relationships emerged during evolution, the current review aims at giving an overview of Leishmania summarizing knowledge and formulating guidelines for LEVs research. In the end, we report, direct methods for specific isolation of LEVs from promastigotes and amastigotes culture supernatant suitable for a range of different downstream applications increasing the compatibility and reproducibility to establish optimal and comparable isolation conditions and full LEVs characterization, and crucial immunomodulatory events triggered by this important group of parasites.
ARTICLE | doi:10.20944/preprints202009.0192.v1
Subject: Life Sciences, Cell & Developmental Biology Keywords: connexin 43; gap junctions; cancer; intercellular communication; breast cancer; cell signaling; tunneling nanotubes; cell–cell communication; tumor microtubes
Online: 9 September 2020 (03:09:50 CEST)
Connexin 43 (Cx43) forms gap junctions that mediate the direct intercellular diffusion of ions and small molecules between adjacent cells. Cx43 displays both pro- and anti-tumorigenic properties, but the mechanisms underlying these characteristics are not fully understood. Tunneling nanotubes (TNTs) are long and thin membrane projections that connect cells, facilitating the exchange of not only small molecules, but also larger proteins, organelles, bacteria, and viruses. Typically, TNTs exhibit increased formation under conditions of cellular stress and are more prominent in cancer cells, where they are generally thought to be pro-metastatic and to provide growth and survival advantages. Cx43 has been described in TNTs, where it is thought to regulate small molecule diffusion through gap junctions. Here, we developed a high-fidelity CRISPR/Cas9 system to knockout (KO) Cx43. We found that loss of Cx43 expression was associated with significantly reduced TNT length and number in breast cancer cell lines. Notably, secreted factors present in conditioned medium stimulated TNTs more potently when derived from Cx43-expressing cells than from KO cells. Moreover, TNT formation was significantly induced by inhibition of several key cancer signaling pathways that both regulate Cx43 and are regulated by Cx43, including RhoA kinase (ROCK), protein kinase A (PKA), focal adhesion kinase (FAK), and p38. Intriguingly, drug-induced stimulation of TNTs was more potent in Cx43 KO cells than in wild-type cells. In conclusion, this work describes a novel non-canonical role for Cx43 in regulating TNTs, identifies key cancer signaling pathways that regulate TNTs in this setting, and provides mechanistic insight into a pro-tumorigenic role of Cx43 in cancer.
REVIEW | doi:10.20944/preprints202111.0116.v1
Subject: Life Sciences, Other Keywords: microglia and astrocytes phenotypes; intercellular crosstalk; lesion microenvironment; neuroinflammation; in vivo glia-to neuron reprogramming; subpial delivery; gut dysbiosis; electrostimulation; rehabilitation; neuroprotective strategies
Online: 5 November 2021 (11:14:51 CET)
Traumatic spinal cord injury (SCI) elicits an acute inflammatory response which comprises numerous cell populations. It is driven by the immediate response of macro-phages and reactive M1 microglia, which triggers activation of genes responsible for the dysregulated microenvironment within the lesion site and in the spinal cord parenchyma immediately adjacent to the lesion. Recently published data indicate that microglia induces astrocyte activation and determines the fate of astrocytes. Conversely, astrocytes have the potency to trigger microglial activation and control their cellular functions. Here we review current information about the release of diverse signaling molecules (pro-inflammatory vs anti-inflammatory) in individual cell phenotypes (microglia, astrocytes, blood inflammatory cells) in acute and subacute SCI stages, and how they contribute to delayed neuronal death in a the surrounding spinal cord tissue which is spared and functional but reactive. In addition, temporal correlation in progressive degeneration of neurons and astrocytes and their functional interactions after SCI are discussed. Finally, the review highlight the time-dependent transformation of reactive mi-croglia (M1) and astrocytes (A1) into their neuroprotective phenotypes (M2a, M2c and A2) which are crucial for spontaneous post-SCI locomotor recovery. We also provide sug-gestions on how to increase functional outcome after SCI and discuss key therapeutic approaches.
ARTICLE | doi:10.20944/preprints202107.0484.v1
Subject: Medicine & Pharmacology, Allergology Keywords: metformin; Natural Killer cells; Cytotoxic T lymphocytes; intercellular adhesion molecule-1 (ICAM-1); Natural Killer G2-D (NKG2D) ligands (NKG2DL); lymphocyte function-associated antigen 1 (LFA-1)
Online: 21 July 2021 (10:54:14 CEST)
Solid tumor cells have an altered metabolism that can protect them from cytotoxic lymphocytes. The antidiabetic drug metformin modifies tumor cell metabolism and several clinical trials are testing its effectiveness for the treatment of solid cancers. The use of metformin in hematologic cancers has received much less attention, although allogeneic cytotoxic lymphocytes are very effective against these tumors. We show here that metformin induces expression of Natural Killer G2-D (NKG2D) ligands (NKG2DL) and intercellular adhesion molecule-1 (ICAM-1), a ligand of the lymphocyte function-associated antigen 1 (LFA-1). This leads to enhance sensitivity to cytotoxic lymphocytes. Overexpression of antiapoptotic Bcl-2 family members decrease both metformin effects. The sensitization to activated cytotoxic lymphocytes is mainly mediated by the increase on ICAM-1 levels, which favors cytotoxic lymphocytes binding to tumor cells. Finally, metformin decreases the growth of human hematological tumor cells in xenograft models, mainly in presence of monoclonal antibodies that recognize tumor antigens. Our results suggest that metformin could improve cytotoxic lymphocyte-mediated therapy.