Online: 1 November 2023 (23:57:02 CET)
This is an opinion piece based on observations from more than two decades of biomedical data mining insights studying health and disease. It has led me to reevaluate modern life and how lived experiences in many parts of the world are being questioned and now answered through the various technological advances that have taken place in biomedical science. Our mitochondria are multi-faceted and the next generation will need to ensure that they develop a strong understanding from a scientific basis for how they are important to our health. The mind-body connection is also now being investigated through researching the networks of mitochondrial bioenergetics. This article provides a brief introduction to how we can reduce chronic disease burden globally, by introducing a simple first algorithm for healthy aging. This work is aimed to jump start the collection of Algorithms for Healthy Aging (AHA) in the context of global populations in their locally lived generational experiences, which may have underlying scientific bases that are yet to be discovered and validated.
ARTICLE | doi:10.20944/preprints202106.0349.v1
Subject: Biology And Life Sciences, Biochemistry And Molecular Biology Keywords: myofibrils; mitochondria; resistance training
Online: 14 June 2021 (10:36:45 CEST)
Resistance training increases myofiber hypertrophy, but the morphological adaptations that occur within myofibers remain largely unresolved. Fifteen males with minimal training experience (24±4 years, 17.9±1.4 kg/m2 lean body mass index) performed 10 weeks of conventional, full-body resistance training (2x weekly). Body composition, the radiological density of the vastus lateralis muscle using peripheral quantitative computed tomography (pQCT), and vastus lateralis muscle biopsies were obtained one week prior to and 72 hours following the last training bout. Fiber typing and the quantification of myofibril and mitochondrial areas per fiber were performed using histology/immunohistochemistry (IHC) techniques. Relative myosin heavy chain and actin protein abundances per wet muscle weight as well as citrate synthase (CS) activity assays were also obtained on tissue lysates. Training increased whole-body lean mass, mid-thigh muscle cross-sectional area, various strength metrics, and mean and type II fiber cross sectional areas (fCSA) (p<0.05). Myofibril areas in type I or II fibers were not altered with training, suggesting a proportional expansion with fCSA increases. Relative myosin heavy chain and actin protein abundances also did not change with training. IHC indicated training increased mitochondrial areas in both fiber types (p=0.018). However, CS activity levels remained unaltered with training. Interestingly, although pQCT-derived muscle density increased with training (p=0.036), suggestive of myofibril packing, a positive association existed between training-induced changes in this metric and changes in type I+II myofibril areas (r=0.600, p=0.018). Shorter-term resistance training seemingly involves a proportional expansion of myofibrils and an accelerated expansion of mitochondria in type I and II fibers. Additionally, histological and biochemical techniques should be viewed independently from one another given the lack of agreement between the variables assessed herein. Finally, the pQCT may be a viable tool to non-invasively track morphological changes in muscle tissue.
ARTICLE | doi:10.20944/preprints201902.0147.v1
Subject: Biology And Life Sciences, Biochemistry And Molecular Biology Keywords: MWCNTs; oxidative stress; mitochondria
Online: 18 February 2019 (08:57:01 CET)
Human exposure to carbon nanotubes (CNTs) can cause health issues due to their chemical–physical features and biological interactions. These nanostructures cause oxidative stress, also due to endogenous ROS production, which increases following mitochondrial impairment. The aim of this in vitro study was to assess the health effects, due to mitochondrial dysfunction, caused by a sub-chronic exposure to a non-acutely toxic dose of multi walled CNTs (raw and functionalised). The A549 cells were exposed to MWCNTs (2 µg mL-1) for 36 days. Periodically, cellular dehydrogenases, pyruvate dehydrogenase kinase 1 (PDK1), cytochrome c release, permeability transition pore (mPTP) opening, transmembrane potential (Δψ m), apoptotic cells, and intracellular ROS were measured. The results, compared to untreated cells and to positive control formed by cells treated with MWCNTs (20 µg mL-1), highlighted the efficiency of homeostasis to counteract ROS overproduction, but a restitutio ad integrum of mitochondrial functionality was not observed. Despite the tendency to restore, the mitochondrial impairment persisted. Overall, the results underlined the tissue damage that can arise following sub-chronic exposure to MWCNTs.
REVIEW | doi:10.20944/preprints202302.0238.v1
Subject: Biology And Life Sciences, Cell And Developmental Biology Keywords: nanoparticles; berberine; metabolism; mitochondria; apoptosis
Online: 14 February 2023 (07:52:01 CET)
Berberine (BBR) is an isoquinoline that inhibits the proliferation of transformed cells in vitro, but due to its poor solubility and bioavailability, it has only moderate therapeutic potential in vivo. Increasing evidence indicates that BBR specifically targets several metabolic, signaling and gene transcription events in transformed cells, altering their progression through the cell cycle and decreasing their metabolic rate and proliferation. In order to further develop BBR as a therapeutic, its mode of cellular internalization and localization within the cell needs to be further examined. BBR’s molecular targets and interactions with kinases, transcription factors and some enzymes are discussed in an attempt to better understand BBR’s role in these important pathways and how they may lead to changes in metabolism. Lastly, this review examines some of the benefits and challenges of using BBR as an inhibitor in cancer cell proliferation in breast cancer and glioblastoma, as two examples. BBR is a potent drug with multiple targets and it is this multiplicity of function that makes BBR such a promising drug for targeting cell metabolism and proliferation.
ARTICLE | doi:10.20944/preprints202302.0183.v1
Subject: Medicine And Pharmacology, Oncology And Oncogenics Keywords: metabolism; mitochondria; cancer; thyroid; diagnostic
Online: 10 February 2023 (07:28:05 CET)
Metabolic adaptations are a hallmark of cancer and may be exploited to develop novel diagnostic and therapeutic tools. Only about 50% of the patients who undergo thyroidectomy due to suspicion of thyroid cancer actually have the disease, highlighting the diagnostic limitations of current tools. We explored the possibility of using non-invasive blood tests to accurately diagnose thyroid cancer. We analyzed blood and thyroid tissue samples from 2 independent cohorts of patients undergoing thyroidectomy at the Hospital Universitario 12 de Octubre (Madrid, Spain). As expected, histological comparisons of thyroid cancer and hyperplasia revealed higher proliferation and apoptotic rates and enhanced vascular alterations in the former. Notably, they also revealed increased levels of membrane-bound phosphorylated AKT, suggestive of enhanced glycolysis, and alterations in mitochondrial sub-cellular distribution. Both characteristics are common metabolic adaptations in primary tumors. These data together with reduced mtDNA copy number and elevated levels of the mitochondrial antioxidant Prx3 in cancer tissue samples suggest the presence of mitochondrial oxidative stress. In plasma, cancer patients showed higher levels of cfDNA and mtDNA. Of note, mtDNA plasma levels inversely correlated with those in the tissue, suggesting that higher death rates were linked to lower mtDNA copy number. In PBMCs, cancer patients showed higher levels of PGC-1, a positive regulator of mitochondrial function, but this increase was not associated with a corresponding induction of its target genes, suggesting a reduced activity in cancer patients. We also observed a significant difference in the PRDX3/PFKFB3 correlation at the gene expression level, between carcinoma and hyperplasia patients, also indicative of increased systemic metabolic stress in cancer patients. The correlation of mtDNA levels in tissue and PBMCs further stressed the interconnection between systemic and tumor metabolism. Evaluation of the mitochondrial gene ND1 in plasma, PBMCs and tissue samples, suggested that it could be a good biomarker for systemic oxidative metabolism, with ND1/mtDNA ratio positively correlating in PBMCs and tissue samples. In contrast, ND4 evaluation would be informative of tumor development, with ND4/mtDNA ratio specifically altered in the tumor context. Taken together, our data suggest that metabolic dysregulation in thyroid cancer can be monitored accurately in blood samples and might be exploited for the accurate discrimination of cancer from hyperplasia.
ARTICLE | doi:10.20944/preprints202109.0466.v1
Subject: Biology And Life Sciences, Biochemistry And Molecular Biology Keywords: ageing; exercise; drosophila; proteome; mitochondria
Online: 28 September 2021 (11:23:15 CEST)
Ageing is a major risk factor for many of the most prevalent diseases, including neurodegenerative disease, cancer and heart disease. As the global population continues to age, behavioural interventions that can promote healthy ageing will improve quality of life and relieve the socio-economic burden that comes with an aged society. Exercise is recognised as an effective intervention against many diseases of ageing, but we don’t know the stage in an individual’s lifetime in which exercise is most effective at promoting healthy ageing and whether it has a direct effect on lifespan. We exercised w1118 Drosophila melanogaster, interrogating effects of sex and group size, at different stages of their lifetime and recorded their lifespan. Climbing scores at 30 days were measured to record differences in fitness in response to exercise. We also assessed the mitochondrial proteome of w1118 Drosophila that had been exercised for one week, alongside mitochondrial respiration measured using High-Resolution Respirometry, to determine changes in mitochondrial physiology in response to exercise. We found that age-targeted exercise interventions improve lifespan in male and female Drosophila, and grouped males exercised in late life had improved climbing scores, when compared with those exercised throughout their entire lifespan. The proteins of the electron transport chain were significantly upregulated in expression after one week of exercise, and complex II linked respiration was significantly increased in exercised -Drosophila. Taken together our study provides a basis to test specific proteins and complex II of the respiratory chain as important effectors of exercise induced healthy ageing.
REVIEW | doi:10.20944/preprints202310.0005.v1
Subject: Biology And Life Sciences, Immunology And Microbiology Keywords: Mitochondria; immune response; activation; secretion; phagocytic
Online: 1 October 2023 (07:55:51 CEST)
Salmonella is the intracellular pathogen and etiological known for the cause of asymptomatic carriage, gastroenteritis, systemic disease (typhoid fever), in severe cases death may also occur. Altered function of mitochondria due to Salmonella infection impacts the immune response. Mitochondria which are recognized as the “powerhouse” of the cells are also know to play central role in the immune metabolism. Mitochondrial dynamics such as fusion, fission, signaling, transport and mitophagy influences the immune system and also maintains the cellular integrity. Mitochondrial DNA and Reactive oxygen species formation also elicits the inflammatory responses. This review discusses the immune metabolism and effect of altered mitochondrial dynamics in case of Salmonella infection.
ARTICLE | doi:10.20944/preprints202309.0914.v1
Subject: Biology And Life Sciences, Biochemistry And Molecular Biology Keywords: Yerba Maté; Metabolism; Obesity; Nutraceuticals; Mitochondria
Online: 14 September 2023 (03:32:04 CEST)
Yerba maté, an herbal tea derived from Ilex paraguariensis, has previously been reported to be protective against obesity-related and other cardiometabolic disorders. Using high-resolution respirometry and reverse-phase high-performance liquid chromatography, the effects of four weeks of yerba maté consumption on mitochondrial efficiency and cellular redox status in skeletal muscle, adipose, and liver, tissues highly relevant to whole body metabolism, were explored in healthy adult mice. Yerba maté treatment increased mitochondrial oxygen consumption in adipose, but not in other tissues examined. Yerba maté increased ATP concentration in skeletal muscle and decreased ATP concentration in adipose. Combined with observed changes in oxygen consumption, these data yielded a significantly higher ATP:O2, a measure of mitochondrial efficiency, in muscle and a significantly lower ATP:O2 in adipose, which were consistent with yerba maté-induced weight loss. Yerba maté treatment also altered the hepatic glutathione (GSH)/glutathione disulfide (GSSG) redox potential to a more reduced redox state, suggesting potential protective effects against oxidative stress and preservation of cellular function. Together, these data indicate beneficial, tissue-specific effects of yerba maté supplementation on mitochondrial bioenergetics and redox states in healthy mice that are protective against obesity.
ARTICLE | doi:10.20944/preprints202308.1195.v1
Subject: Biology And Life Sciences, Biochemistry And Molecular Biology Keywords: hypochlorite; mitochondria; anthracene carboxyimide; fluorescent probe
Online: 16 August 2023 (10:07:22 CEST)
Mitochondrial hypochlorite (ClO-) plays important and often contradictory roles in maintaining the redox balance of mitochondria. Abnormal ClO- levels can induce mitochondrial inactivation and further cause cell apoptosis. Herein. we have developed an anthracene carboxyimide-based fluorescent probe mito-ACS for imaging mitochondrial ClO- in living cells. This probe exhibits some distinctive features as excellent resistance to photobleaching, high selectivity and sensitivity, as well as good water solubility. Mito-ACS showed a noticeable fluorescence response toward ClO-with a fast response (within 6 s) and a low detection limit (23 nM). Moreover, the introduction of triphenylphosphonium makes the probe soluble in water and selectively localizes to mitochondria. Furthermore, mito-ACS was successfully applied to image mitochondria ClO- in living cells with low toxicity. Remarkably. the less used fluorophore anthracene carboxyimide exhibiting excellent photostability and desirable optical properties provides a promising application prospect in biological systems.
ARTICLE | doi:10.20944/preprints202305.1915.v1
Subject: Public Health And Healthcare, Public, Environmental And Occupational Health Keywords: Arsenic, PGC-1α, Mitochondria, Hippocampus, Apoptosis
Online: 26 May 2023 (10:21:09 CEST)
Chronic exposure to arsenic in drinking-water damage to cognitive function, and nerve cells apoptosis is one of primary characteristic. The damage of mitochondrial structure and/or function is one of the main characteristics of apoptosis. Peroxisome proliferator activated receptor γ Coactivator α (PGC-1α) is involved in the regulation of mitochondrial biogenesis, energy metabolism and apoptosis. In this study, we aimed to study role of PGC-1α in sodium arsenite (NaAsO2)-induced mitochondrial apoptosis in rat hippocampal cells. We discovered that arsenic-induced apoptosis increased in rat hippocampus increased with NaAsO2 (0, 2, 10, and 50 mg/L, orally via drinking water for 12 weeks) exposure by TUNEL assay, and the structure of mitochondria was incomplete, swollen, lysosomes and lipofuscin increasing, and nuclear membrane shrunk observed by transmission electron microscope. Furthermore, NaAsO2 reduced levels of Bcl-2 and PGC-1α, increased the levels of Bax and Cytochrome C expression. Moreover, correlation analysis showed that brain arsenic content was negatively correlated with PGC-1α level and brain ATP content, respectively; PGC-1α level was negatively correlated with apoptosis rate; Brain ATP content was positively correlated with PGC-1α level; but no significant correlation between ATP content and apoptosis has been observed in this study. Taken together, the results of present study indicate that NaAsO2-induced mitochondrial pathway apoptosis is related to the reduction of PGC-1α, accompanied by ATP depletion.
ARTICLE | doi:10.20944/preprints202304.0362.v1
Subject: Biology And Life Sciences, Agricultural Science And Agronomy Keywords: alternative oxidase; mitochondria; critical node; rice
Online: 14 April 2023 (09:56:24 CEST)
Mitochondrial alternative oxidase 1a (AOX1a) plays an extremely important role in critical node of seed viability. However, the regulatory mechanism is still poorly understood. The study aims to identify regulatory mechanisms by comparing between OsAOX1a-RNAi and wild type (WT) rice seed during artificial aging treatment. Gain weight and P50 significantly decreased in OsAOX1a-RNAi rice seed, indicating that there might be impaired in seed development and storability. Compared to WT seeds in the 100%, 90%, 80%, and 70% germination, respectively, NADH and succinate-dependent O2 consumption, the activity mitochondrial malate dehydro-genase and ATP contents were decreased in OsAOX1a-RNAi seeds in the 100%, 90%, 80%, and 70% germination, respectively, indicating that mitochondrial status in the OsAOX1a-RNAi seeds after imbibition was weaken than the WT. In addition to, the reduced abundance of complex I N and P module subunits might showed that the capacity of mitochondrial electron transfer chain was significantly inhibited in the OsAOX1a-RNAi seed at critical node of seed viability. Above results might indicated that the ATP production was impaired in OsAOX1a-RNAi seeds during ageing. Therefore, we conclude that the activities of mitochondrial metabolism and alternative pathways were severely inhibited in OsAOX1a-RNAi seeds at critical node of viability, which was leading to accelerate the collapse of seed viability. The precise regulatory mechanism of the alternative pathway at the critical node of viability still needs to be further analyzed.
ARTICLE | doi:10.20944/preprints202212.0091.v1
Subject: Biology And Life Sciences, Biochemistry And Molecular Biology Keywords: Thyroid metabolism; Krebs cycle; Mitochondria; MAFLD
Online: 6 December 2022 (02:36:44 CET)
Metabolic dysfunction associated fatty liver disease (MAFLD) has gained worldwide attention as a public health problem. Nonetheless, lack of enough mechanistic knowledge restrains effective treatments. It is known that T3 regulate hepatic lipid metabolism, and mitochondrial function. Liver dysfunction of T3 contributes to MAFLD, but its role is not fully understood. Objective: To evaluate the role of T3 dysfunction in the progression of MAFLD in an animal model. Method-ology: Male/adult Sprague Dawley rats (n=20) were allocated to a control group (standard di-et–2.93kcal/g) and diet group (CDHF–4.3kcal/g). Euthanasia took place in the 28th week. D3 ac-tivity and expression, UCP2 and D1 expression, REDOX status, mitochondrial, Krebs cycle and endoplasmic reticulum homeostasis in liver tissue were measured. Results: We observed an in-crease in D3 activity/expression (P<0.001) related to increased TBARS and carbonyls and GSH reduction in the MAFLD group (P<0.05). There was a T3-dependent decrease in UCP2 expression (P=0.01), mitochondrial capacity, respiratory activity with increased endoplasmic reticulum stress in the MAFLD group (P < 0.001). Surprisingly, in and environment with lower T3 levels we observed an augmented alpha-ketoglutarate dehydrogenase (KGDH) and glutamate dehydro-genase (GDH) enzymes activity (P<0.05). Conclusion: Induced D3, triggered by changes in the REDOX state, decreases T3 availability, and hepatic mitochondrial capacity. The Krebs cycle en-zymes were altered as well as reticulum stress. Taken together, these results shed new light on the role of T3 metabolism in MAFLD and new treatment opportunities.
HYPOTHESIS | doi:10.20944/preprints202201.0171.v3
Subject: Medicine And Pharmacology, Oncology And Oncogenics Keywords: ATP; Cancer cell; Cancer Treatment; Mitochondria; T cell
Online: 27 June 2022 (05:07:50 CEST)
Like living organisms, cancer cells require energy to survive and interact with their environment. Mitochondria are the main organelles for energy production and cellular metabolism. Recently, investigators demonstrated that cancer cells can hijack mitochondria from immune cells. This behavior sheds light on a pivotal piece in the cancer puzzle, the ‘dependence’ on the normal cells. This article illustrates the benefits of new, functional mitochondria for cancer cells that urge them to hijack mitochondria. It describes how functional mitochondria help cancer cells’ survival in the harsh tumor microenvironment, immune evasion, progression, and treatment resistance. Recent evidence has put forward the pivotal role of mitochondria in cancer stem cells’ metabolism. This theory highlights the mitochondria in cancer biology and explains how targeted anti-mitochondrial treatments can improve oncological outcomes.
ARTICLE | doi:10.20944/preprints202106.0731.v1
Subject: Biology And Life Sciences, Anatomy And Physiology Keywords: mitochondria; physiological uncoupling; permeability transition; reversibility
Online: 30 June 2021 (11:37:53 CEST)
Abstract: The Saccharomyces cerevisiae mitochondrial unspecific pore (ScMUC) is an uncoupling unspecific pore that shares some similarities with the mammalian permeability transition pore (mPTP). When open, both channels deplete ion and proton gradients across the inner mitochon-drial membrane. However, the role of mPTP is to reversibly open to protect cells against stress. If mPTP remains stuck in the open position the cell dies. In contrast, ScMUC is probably dedicated to deplete oxygen from the medium in order to kill competing organisms. Such O2 depletion would be better achieved if oxidative phosphorylation is at least mildly uncoupled. Still, when oxida-tive phosphorylation is needed ScMUC should be able to close. To test this, the reversible opening and closing of ScMUC in the presence of different effectors was tested in isolated mitochondria from S. cerevisiae. Evaluations were conducted at different incubation times, monitoring the rate of O2 consumption, mitochondrial swelling and the transmembrane potential. It was observed that ScMUC did remain reversibly open for minutes. A low energy charge (ATP/ADP) closed the chan-nel. In addition, high Ca2+ promoted closing and it was a highly powerful effector.
ARTICLE | doi:10.20944/preprints202102.0182.v1
Subject: Biology And Life Sciences, Biochemistry And Molecular Biology Keywords: yeast; anhydrobiosis; dehydration-rehydration; metabolism; mitochondria
Online: 8 February 2021 (10:39:47 CET)
Anhydrobiosis is the state of life when cells get into waterless conditions and gradually cease their metabolism. In this study, we determined the sequence of events in Saccharomyces cerevisiae energy metabolism during processes of dehydration and rehydration. The intensities of respiration and acidification of the medium, the amounts of Phenyldicarbaundecaborane (PCB-) bound to yeast membranes, and the capabilities of cells to accumulate K+ were assayed using electrochemical monitoring system, and intracellular content of ATP was measured using bioluminescence assay. Mesophilic, semi-resistant to desiccation S. cerevisiae strain 14 and thermotolerant, very resistant to desiccation S. cerevisiae strain 77 cells were compared. After 22 h of drying it was possible to restore the respiration activity of very resistant to desiccation strain 77 cells, especially when glucose was available. PCB- binding also indicated considerably higher metabolic activity of dehydrated S. cerevisiae strain 77 cells. Electrochemical K+ content and medium acidification assays indicated that permeabilization of the plasma membrane in cells of both strains started almost simultaneously, after 8-10 h of desiccation, but semi-resistant strain 14 cells were longer keeping K+ gradient and stronger acidifying the medium. For both cells, the fast rehydration in water was less efficient compared to reactivation in the growth medium, indicating the need for nutrients for the recovery. Higher viability of strain 77 cells after rehydration could be due to the higher stability of their mitochondria.
REVIEW | doi:10.20944/preprints202012.0079.v1
Subject: Medicine And Pharmacology, Immunology And Allergy Keywords: Mitochondria; Alzheimer’s Disease; mitophagy; neurodegeneration; aging
Online: 3 December 2020 (10:36:29 CET)
Stress mechanisms have long been associated with neuronal loss and neurodegenerative diseases. The origin of cell stress and neuronal loss likely stems from multiple pathways. These include (but are not limited to) bioenergetic failure, neuroinflammation, and loss of proteostasis. Cells have adapted compensatory mechanisms to overcome stress and circumvent death. One mechanism is mitophagy. Recent studies have implicated mitophagy in several neurodegenerative diseases and clinical trials are underway which target mitophagy pathways. Here, we review mitophagy pathways, the role of mitophagy in neurodegeneration, potential therapeutics, and the need for further study.
ARTICLE | doi:10.20944/preprints202006.0222.v1
Subject: Biology And Life Sciences, Biochemistry And Molecular Biology Keywords: astaxanthin; muscle atrophy; mitochondria; oxidative stress
Online: 17 June 2020 (13:29:15 CEST)
Astaxanthin (AX) is a carotenoid that exerts potent antioxidant activity and acts in the lipid bilayer. This study aimed to investigate the effects of AX on muscle atrophy-mediated disturbance of mitochondria that have a lipid bilayer. Tail suspension was used to establish muscle- atrophied mouse models. AX diet fed to tail-suspension mice prevented loss of muscle weight and decreased myofiber size in the soleus muscle. Additionally, AX improved down-regulation of mitochondrial respiratory chain complexes II and III in the soleus muscle after tail suspension. To confirm the AX phenotype in the soleus muscle, we examined its effects on mitochondria using Sol8 myotubes derived from the soleus muscle. We found that AX was preferentially detected in the mitochondrial fraction; it significantly suppressed mitochondrial complex III-driven production of reactive oxygen species in Sol8 myotubes. Moreover, AX inhibited the activation of caspase 3 via inhibiting the release of cytochrome c into the cytosol in antimycin A-treated Sol8 myotubes. These results suggested that AX inhibited mitochondrial oxidative stress through a mitochondria-mediated apoptosis pathway and thus prevented muscle atrophy.
ARTICLE | doi:10.20944/preprints201909.0059.v2
Subject: Biology And Life Sciences, Cell And Developmental Biology Keywords: Oxidative stress, MFN2, mitochondria, fusion/fission
Online: 9 September 2019 (11:46:36 CEST)
Charcot-Marie-Tooth disease is a hereditary polyneuropathy caused by mutations in Mitofusin-2 (MFN2), a GTPase in the outer mitochondrial membrane involved in the regulation of mitochondrial fusion and bioenergetics. Autosomal-dominant inheritance of a R94Q mutation in MFN2 causes the axonal subtype 2A2A which is characterized by early onset and progressive atrophy of distal muscles caused by motoneuronal degeneration. Here, we studied mitochondrial shape, respiration, cytosolic and mitochondrial ATP content as well as mitochondrial quality control in MFN2-deficient fibroblasts stably expressing wildtype or R94Q MFN2. Under normal culture conditions, R94Q cells had slightly more fragmented mitochondria but a similar mitochondrial oxygen consumption, membrane potential and ATP production as wildtype cells. However, when inducing mild oxidative stress 24 h before analysis using 100 µM hydrogen peroxide, R94Q cells exhibited significantly increased respiration but decreased mitochondrial ATP production. This was accompanied by increased glucose uptake and an upregulation of hexokinase 1 and pyruvate kinase M2 suggesting increased pyruvate shuttling into mitochondria. As these changes coincided with decreased levels of PINK1/Parkin-mediated mitophagy in R94Q cells, we conclude that the disease-causing R94Q mutation in MFN2 causes uncoupling of mitochondrial respiration from ATP production by a less efficient mitochondrial quality control triggered by oxidative stress.
REVIEW | doi:10.20944/preprints201711.0176.v1
Subject: Biology And Life Sciences, Biochemistry And Molecular Biology Keywords: mitochondria; proteolysis; protein half-life; ubiquitin
Online: 27 November 2017 (09:18:27 CET)
The mitochondrial network is a dynamic organization within eukaryotic cells that participates in a variety of essential cellular processes, such as ATP synthesis, central metabolism, apoptosis and inflammation. The mitochondrial network is balanced between rates of fusion and fission that respond to pathophysiologic signals to coordinate appropriate mitochondrial processes. Mitochondrial fusion and fission are regulated by proteins that either reside or translocate to the inner or outer mitochondrial membranes or are soluble in the inter-membrane space. Mitochondrial fission and fusion are performed by GTPases on the outer and inner mitochondrial membranes with the assistance of other mitochondrial proteins. Due to the essential nature of mitochondrial function for cellular homeostasis regulation of mitochondrial dynamics is under strict control. Some of the mechanisms used to regulate the function of these proteins are post-translational proteolysis and/or turnover and this review will discuss these mechanisms required for correct mitochondrial network organization.
REVIEW | doi:10.20944/preprints201706.0127.v1
Subject: Biology And Life Sciences, Animal Science, Veterinary Science And Zoology Keywords: sex determination; exual systems; bivalvia; mitochondria
Online: 30 June 2017 (07:28:18 CEST)
In this review, we provide an overview of the current knowledge on the different sexual systems and sex determining mechanisms in bivalves, with a focus on the various epigenetic and genetic factors that may be involved. The final section of the review provides recent discoveries on sex-specific mitochondrial genes in bivalves possessing the unconventional system of doubly uniparental inheritance of mitochondria (which is found in several members of the orders Mytiloida, Unionoida, Veneroida and Nuculanoida). The genes involved in this developmental pathway could represent the first sex determination system in animals in which mitochondrially-encoded genes are directly involved.
REVIEW | doi:10.20944/preprints202311.1701.v1
Subject: Chemistry And Materials Science, Ceramics And Composites Keywords: hydroxyapatite; bone grafting; nanoparticles; immune response; mitochondria
Online: 28 November 2023 (06:56:44 CET)
Abstract: The centrepiece of this analytical review is the metabolism of hydroxyapatite in its natural, bone, and synthetic forms, where the mitochondria-mediated mechanism may serve as the leading mechanism. The possibility that osteoblast mitochondria play an important role in the initial stages of bone mineralisation is discussed. Furthermore, the paper highlights the key role of mitochondria in the metabolism of synthetic hydroxyapatite.Differences between the results of in vivo and in vitro studies using synthetic hydroxyapatite of different morphologies are also detailed. It is noted that long-term infiltration with immune cells and in vivo studies are necessary to adequately evaluate hydroxyapatite as a bone-plastic material.Particular attention is given to the interaction of hydroxyapatite with immune cells and its ability to affect the ribosomes and mitochondria of cells. Due to its mechanical properties, scalability and potential use for the treatment of extensive bone defects of tumor origin, hydroxyapatite is a promising material.This study also highlights the importance of further development of in vitro research methods in the context of their biomimeticity. Overall, this work offers a theoretical direction for future studies of hydroxyapatite as a bone grafting material and emphasises the value of in vivo studies.
REVIEW | doi:10.20944/preprints202311.0348.v1
Subject: Medicine And Pharmacology, Neuroscience And Neurology Keywords: Parkinson’s disease; immunity; neuroinflammation; mitochondria; dysbiosis; infections.
Online: 6 November 2023 (11:09:33 CET)
Recent research has unveiled intriguing insights suggesting that the body's immune system may be implicated in Parkinson's disease (PD) development. Studies have observed disparities in pro-inflammatory and anti-inflammatory markers between PD patients and healthy individuals. This finding underscores the potential influence of immune system dysfunction in the genesis of this condition. A dysfunctional immune system can serve as a primary catalyst for systemic in-flammation in the body, which may contribute to the emergence of various brain disorders. The identification of several genes associated with PD, as well as their connection to neuroinflamma-tion, raises the likelihood of disease susceptibility. Moreover, advancing age and mitochondrial dysfunction can weaken the immune system, potentially implicating them in the onset of the dis-ease, particularly among older individuals. Compromised integrity of the blood-brain barrier could facilitate the immune system's access to brain tissue. This exposure may lead to encounters with native antigens or infections, potentially triggering an autoimmune response. Furthermore, there is mounting evidence supporting the notion that gut dysbiosis might represent an initial trigger for brain inflammation, ultimately promoting neurodegeneration. In this comprehensive review, we will delve into the numerous hypotheses surrounding the role of both innate and adaptive immunity in PD.
ARTICLE | doi:10.20944/preprints202311.0288.v1
Subject: Biology And Life Sciences, Plant Sciences Keywords: Arabidopsis thaliana; gene expression; mitochondria; phytohormones; RPOTmp
Online: 6 November 2023 (08:04:28 CET)
Coordination of activities between nuclei and organelles in plant cells involves information exchange, in which phytohormones may play an essential role. Therefore, dissection of the mechanisms of hormone-related integration between phytohormones and mitochondria is an important and challenging task. Here, we found that inputs from multiple hormones may cause changes in transcript accumulation of mitochondrial-encoded genes and nuclear genes encoding mitochondrial (mt) proteins. In particular, treatments with exogenous hormones induced changes in GUS expression in the reporter line possessing a 5'-deletion fragment of the RPOTmp promoter. These changes corresponded in part to up- or downregulation of RPOTmp in wild-type plants, which affected the transcription of mt-encoded genes, implying that promoter fragments of the RPOTmp gene are functionally involved in responses to IAA (indole-3-acetic acid), ACC (1-aminocyclopropane-1-carboxylic acid), and ABA (abscisic acid). Hormone-dependent modulations in the expression of mt-encoded genes can also be mediated through mitochondrial transcription termination factors 15, 17, and 18 of the mTERF family and genes for tetratricopeptide repeat proteins that are coexpressed with mTERF genes, in addition to SWIB5 encoding a mitochondrial SWI/SNF (nucleosome remodelling) complex B protein. These genes specifically responded to hormone treatment, displaying both negative and positive regulation in a context-dependent manner. According to bioinformatic resources, their promoter regions possess putative cis-acting elements involved in responses to phytohormones. Alternatively, hormone-related transcriptional activity of these genes may be modulated indirectly, which is especially relevant for brassinosteroids (BS). In general, the results of the study indicate that hormones are essential mediators that are able to cause alterations in the transcript accumulation of mt-related nuclear genes, which in turn trigger the expression of mt genes.
ARTICLE | doi:10.20944/preprints202310.1966.v1
Subject: Biology And Life Sciences, Aquatic Science Keywords: Elongate loach; Cobititdae; mitochondria genome; phylogenetic analysis
Online: 31 October 2023 (03:00:06 CET)
Elongate loach (Leptobotia elongata) is an endemic fish in China. Previous studies have provided some insights into the mitochondrial genome composition, and the phylogenetic relationships of L. elongata inferred using protein-coding genes (PCGs). However, the detailed information about is limited. Therefore, in this study, we sequenced the complete mitochondrial genome of L. elongata and analyzed its structural characteristics. The PCGs and mitochondrial genome were used for selective stress analysis and genomic comparative analysis respectively. The complete mitochondrial genome of the L. elongata, together with those of 36 Cyprinidae species, was used to infer the phylogenetic relationships of the Cobitidae family through maximum likelihood (ML) reconstruction. The results showed that the genome sequence has a full length of 16,591 bp, which includes 13 PCGs, 22 transfer RNA genes (tRNA), two ribosomal RNA genes (rRNA), and two non-coding regions (CR D-loop and light chain sub-chain replication origin OL). Overall, L. elongata shared the same gene arrangement and composition of the mitochondrial genes with other teleost fishes. The Ka/Ks ratios of all mitochondrial PCGs were less than 1, indicating that all the PCGs were evolving under purifying selection. Genome comparison analyses showed a significant sequence homology of species of Leptobotia. A significant identity between L. elongata and the other 5 Leptobotia species was observed in the visualization result, except for L. mantschurica, which lacked the tRNA-Arg gene and had a shorter tRNA-Asp gene. The phylogenetic tree revealed that the Cobitidae species examined here can be grouped into two clades, with L. elongata forming a sister relationship with L. microphthalma. This study could provide additional inferences for a better understanding of the phylogenetic relationships among Cobititdae species.
ARTICLE | doi:10.20944/preprints202310.0829.v1
Subject: Biology And Life Sciences, Parasitology Keywords: chagas; cardiomyopathy; mitochondria; haplgroups; variants; copy-number
Online: 13 October 2023 (03:03:37 CEST)
Cardiomyopathies are major causes of heart failure. Chagas disease (CD) is caused by the parasite Trypanosoma cruzi, and it is endemic in Central, South America. Thirty percent of the cases evolve into chronic cardiomyopathy (CCC) with worse prognosis as compared with other cardiomyopathies. In vivo bioenergetic analysis and ex vivo proteomic analysis of myocardial tissues highlighted worse mitochondrial dysfunction in CCC, and previous studies identified nuclear-encoded mitochondrial gene variants segregating with CCC. Here, we assessed the role of the mitochondrial genome through mtDNA copy number variations and mtDNA haplotyping and sequencing from heart or blood tissues of severe, moderate CCC and asymptomatic/indeterminate Chagas disease as well as healthy controls as an attempt to help decipher mitochondrial-intrinsic genetic involvement in Chagas disease development. We have found that mtDNA copy number was significantly lower in CCC than in heart tissue from healthy individuals, while blood mtDNA content was similar among asymptomatic Chagas disease, moderate and severe CCC patients. MtDNA haplogrouping study has indicated that African haplogroups were over represented in the Chagas subject groups in comparison with Brazilian healthy individuals. The European lineage is associated to protection against cardiomyopathy and the macro haplogroup H is associated with increased risk towards CCC. By mitochondria DNA sequencing, 84 mtDNA-encoded protein sequence pathogenic variants were associated with CCC. Among them, two variants were associated to left ventricular non-compaction and two to hypertrophic cardiomyopathy. The finding that mitochondrial protein-coding SNPs and mitochondrial haplogroups associate with risk of evolving to CCC is consistent with a key role of mitochondrial DNA in the development of Chronic Chagas disease Cardiomyopathy.
ARTICLE | doi:10.20944/preprints202310.0026.v1
Subject: Medicine And Pharmacology, Gastroenterology And Hepatology Keywords: Acute pancreatitis; Heparanase; Lipase; Amylase; Mitochondria; NSAIDs
Online: 2 October 2023 (03:22:52 CEST)
Abstract: Acute pancreatitis (AP) is a common gastrointestinal disease with high morbidity and mortality rate. Unfortunately, neither the etiology nor the pathophysiology of AP are fully un-derstood and causal treatment options are not available. Recently we demonstrated that Hepa-ranase (Hpa) is adversely involved in the pathogenesis of AP and inhibition of this enzyme ameliorates the manifestation of the disease. Moreover, a pioneer study demonstrated that As-pirin has inhibitory effect on Hpa. Another compound, which possesses a mild pan-creato-protective effect against AP, is Trehalose, a common disaccharide. We hypothesize that combination of Aspirin, Trehalose, PG545 (Pixatimod) and SST0001 (Roneparstat), specific inhib-itors of Hpa, may exert pancreato-protective effect better than each drug alone. Thus, the current study examines the pancreato-protective effects of Aspirin, Trehalose, PG545 and SST0001 in ex-perimental model of AP induced by Cerulein in wild-type (WT) and Hpa over-expressing (Hpa-Tg) mice. Cerulein-induced AP in WT mice was associated with significant rises in the se-rum levels of Lipase (X4) and amylase (X3) with enhancement of pancreatic edema index, inflammatory response, and autophagy. Responses to cerulein were all more profound in heparanase transgenic (Hpa-Tg) mice vs wild-type (WT) mice, evident by X7 and X5 folds increase in lipase and amylase levels, respectively. Treatment with Aspirin or Trehalose alone and even more so in combination with PG545 or SST0001 were highly effective, restoring the serum level of lipase back to the basal level. Importantly, a novel newly synthesized compound termed Aspirlose effectively ameliorated the pathogenesis of AP as a single agent. Collectively, the results strongly indicate that targeting Hpa by using anti-Hpa drug combinations constitute a novel therapy for this common orphan disease.
REVIEW | doi:10.20944/preprints202306.1986.v1
Subject: Biology And Life Sciences, Neuroscience And Neurology Keywords: idiopathic macular hole; estrogen; cone photoreceptor; mitochondria
Online: 28 June 2023 (10:11:11 CEST)
The aim of this review was to identify a new potential reason for the development of macular holes in relation to the female sex and to explain the possible underlying pathway. This approach was based on the evaluation of anatomical, physiological, and morphological analyses currently available in the literature. The findings showed that estrogen exerts a protective effect on the neuroretina. However, this protection may be lost by sudden decrease in estrogen levels during menopause. A gen analysis in zebra fish showed that estrogen may influence Müller and cone cells. Both cell types are responsible for the binding of the fovea structure. Cone implicit time in full-field 30-Hz flicker electroretinography is a predictor of visual outcome after surgery for macular hole. In conclusion, the fovea cone, through its sensibility to estrogen and high energy consumption, may be very vulnerable to damage caused by a sudden change in the concentration of estrogen in menopausal females. Such changes may result in cone degeneration and the development of a hole in the fovea, as in the case of macular holes. This review revealed that the cone under the decreasing influence of estrogen may play a key role with regards to the etiology of development of macular hole. This aspect may be of strategic importance in prophylactic therapy for the prevention of the development of macular hole in premenopausal females or after ocular trauma.
REVIEW | doi:10.20944/preprints202305.2112.v1
Subject: Biology And Life Sciences, Aging Keywords: ATP production; mitochondrial network; mitochondria dynamics, MCU
Online: 30 May 2023 (10:32:39 CEST)
Exercise produces oxidants from a variety of intracellular sources, including NADPH oxidases (NOX) and mitochondria. Exercise-derived ROS are beneficial, and the amount and location of these ROS are important to avoid muscle damage associated with oxidative stress. We discuss here some of the evidence that involves ROS production associated with skeletal muscle contraction and the potential oxidative stress associated with muscle contraction. We also discuss the potential role of H2O2 produced after NOX activation in the regulation of glucose transport in skeletal muscle. Finally, we propose a model based on evidence for the role of different populations of mitochondria in skeletal muscle in the regulation of ATP production upon exercise. The sub-sarcolemmal population of mitochondria has the enzymatic and metabolic components to establish a high mitochondrial membrane potential when fissioned at rest but lacks the capacity to produce ATP; calcium entry to the mitochondria will further increase the metabolic input. Upon exercise, sub-sarcolemmal mitochondria will fuse to intermyofibrillar mitochondria and will transfer the membrane potential to them. These mitochondria are rich in ATP synthase and will subsequentially produce the ATP needed for muscle contraction in long-term exercise. These events will optimize energy use and minimize mitochondria ROS production.
REVIEW | doi:10.20944/preprints202302.0454.v1
Subject: Biology And Life Sciences, Biochemistry And Molecular Biology Keywords: Astrocytes, Microglia, Mitochondria, Neurons, Oligodendrocytes, Oxidative stress
Online: 27 February 2023 (07:34:12 CET)
Neurodegeneration is an age-dependent progressive phenomenon with no defined cause. Aging is the main risk factor for neurodegenerative diseases. During aging, activated microglia undergoes phenotypic alterations that can lead to neuroinflammation, which is well accepted event in the pathogenesis of neurodegenerative diseases. Several common mechanisms are shared by genetically or pathologically distinct neurodegenerative diseases, such as excitotoxicity, mitochondrial deficits and oxidative stress, protein misfolding and translational dysfunction, autophagy and microglia activation. Progressive loss of neuronal population due to increased oxidative stress leads to neurodegenerative diseases mostly due to the accumulation of dysfunctional mitochondria. Mitochondrial dysfunction and excessive neuroinflammatory responses are both sufficient to induce pathology in age-dependent neurodegeneration. Therefore, mitochondrial quality control is key determinant for the health and survival of neuronal cells in the brain. Research has been primarily focused to demonstrate the significance of neuronal mitochondrial health, despite the important contributions of non-neuronal cells that constitutes significant portion of the brain volume. Moreover, mitochondrial morphology and function are distinctly diverse in different tissues; however, little is known about their molecular diversity among cell types. Mitochondrial dynamics and quality in different cell types markedly decides the fate of overall brain health, therefore it is not justifiable to overlook non-neuronal cells and their significant and active contribution in facilitating overall neuronal health. In this review article, we aim to discuss the mitochondrial quality control of different cell types in the brain and how important and remarkable is the diversity and highly synchronized connecting property of non-neuronal cells in keeping the neurons healthy to control neurodegeneration.
REVIEW | doi:10.20944/preprints202208.0061.v1
Subject: Medicine And Pharmacology, Neuroscience And Neurology Keywords: alpha-synuclein; energy; H2O2; mitochondria; neurodegenerative disease
Online: 2 August 2022 (10:13:50 CEST)
The number of people with neurodegenerative disease continues to increase every year. A new perspective is needed in overcoming this disease. In this review, researchers collected information about epigenetics and energy factors of neurodegenerative disease driven by mitochondria. Mitochondrial epigenetic dysregulation can cause damage to the neuron system. The increase in the amount and interaction of alpha-synuclein with SAMM50 in the mitochondria is one of the factors causing neurodegenerative disease. As an energy provider in the body, the existence of harmonization in the regulation of mitochondria specifically the mitochondrial outer membrane is important. Hydrogen peroxide (H2O2) has neuroprotective abilities to overcome the impairment function of mitochondria in neurodegenerative patients. Based on the computational simulation of this case, it can be used as the basic concept for the development of the role of H2O2 in neurodegenerative disease.
ARTICLE | doi:10.20944/preprints202208.0045.v1
Subject: Biology And Life Sciences, Endocrinology And Metabolism Keywords: sideroflexin; SFXN1; mitochondria; ATAD3A; 17beta-HSD10; TIM50
Online: 2 August 2022 (07:46:32 CEST)
Sideroflexins (SFXN) are evolutionarily conserved mitochondrial carriers belonging to the SCL56 family. Until recently, the metabolites transported by SFXN were unknown and they were thought to be transporters of a metabolite involved in iron homeostasis. SFXN1 is now known as the mitochondrial serine transporter. Because little is known about SFXN1 interactome, we launched a high-throughput search of SFXN1 binding partners with the aim to better understand its mitochondrial functions. Using a large-scale identification of SFXN1 physical partners based on co-immunoprecipitation followed by shotgun mass spectrometry (coIP-MS), we identified 96 putative SFXN1 interactants in the MCF7 human cell line. Our in-silico analysis of the SFXN1 interactome highlights biological processes linked to mitochondrial organization, electron transport chain and transmembrane transport. Among SFXN1 potential physical partners, ATAD3A and 17-HSD10, two proteins associated with neurological disorders and neurodegeneration, were further confirmed as interactants using different human cell lines. Further work will be needed to investigate the significance of these interactions in neurological disorders.
REVIEW | doi:10.20944/preprints202205.0289.v1
Subject: Biology And Life Sciences, Biochemistry And Molecular Biology Keywords: mitochondria; reactive species; eustress; distress; bioenergetic; microbiota
Online: 23 May 2022 (09:41:06 CEST)
From oxidative eustress and distress, to bioenergetic metabolism, and cell death, the reactive species interactome (RSI) and mitochondria are two connected metabolisms that require further investigation improving redox medicine. The step before, finding new clues needs a comprehensive discussion of the two metabolisms, and their relationship. Here, the review focuses on the RSI-mitochondria axis, from mitochondrial roles to crosstalk between mitochondria and other organelles, and the major implication of the RSI in mitochondrial roles. Specifically, the review discussed the apoptosis-necroptosis-ferroptosis death traingle, mitochondrial protein quality control system, calcium homeostasis, and mitochondrial metabolome. Through mitochondrial diseases, and mitochondrial dysfunction associated with diseases, the RSI-mitochondria axis is proposed as a brand-new perspective, including with the involvement of bacterial microbiota, on redox signaling, and redox medicine.
REVIEW | doi:10.20944/preprints202202.0219.v1
Subject: Biology And Life Sciences, Biochemistry And Molecular Biology Keywords: mitochondria; ATP synthase; cell death; neurodegenerative diseases.
Online: 18 February 2022 (02:13:31 CET)
The ATP synthase is a mitochondrial complex embedded in the inner mitochondrial membrane. The enzyme is under the double genetic control of the mitochondrial DNA (mtDNA) and nuclear DNA (nDNA). Fatal human diseases have been associated with defects in ATP synthase (Complex V) activity linked to mtDNA or nDNA pathogenetic variants in genes encoding structural subunits or assembly factors. Mitochondrial post-translational modifications of key amino acids, reduced/increased subunit expression, or protein to protein ATP synthase interaction, are also some of the mechanisms involved in the age-related disease pathway. All the major neurodegenerative diseases: Parkinson’s, Alzheimer’s and motor neuron diseases such as Amyotrophic Lateral Sclerosis highlight an impaired ATP generation in a mechanism involving the permeability transition pore that triggers a cellular homeostasis failure responsible for different forms of regulated cell death. In this review, we will explore ATP synthase assembly and function in physiological and pathological conditions by referring to the recent cryo-EM studies and by exploring human diseases models.
ARTICLE | doi:10.20944/preprints202201.0116.v1
Subject: Medicine And Pharmacology, Anesthesiology And Pain Medicine Keywords: Ischaemia/reperfusion injury; Development; Mitochondria; Immature Heart
Online: 10 January 2022 (13:38:07 CET)
Metabolic and ionic changes during ischaemia predispose the heart to the damaging effects of reperfusion. Such changes and the resulting injury differ between immature and adult heart. Therefore, cardioprotective strategies for adults need to be tested in immature heart. We have recently shown that simultaneous activation of PKA and EPAC confers marked cardioprotection in adult hearts. The aim of this study is to investigate the efficacy of this intervention in immature hearts and determine whether the mitochondrial permeability transition pore (MPTP) is involved. Isolated perfused Langendorff hearts from both adult and immature rats were exposed to global ischaemia and reperfusion injury (I/R) following control perfusion or perfusion after an equilibra-tion period with activators of PKA and/or EPAC. Functional outcome and reperfusion injury were measured and in parallel, mitochondria were isolated following 5 min reperfusion to determine whether cardioprotective interventions involved changes in MPTP opening behaviour. Perfusion for 5 minutes preceding ischaemia of injury- matched adult and immature hearts with 5 µM 8-Br (8-Br-cAMP-AM), an activator of both PKA and EPAC, led to significant reduction in post-reperfusion CK release and infarct size. Perfusion with this agent also led to a reduction in MPTP opening propensity in both adult and immature hearts. These data show that immature hearts are innately more resistant to I/R injury than adults, and that this is due to a reduced ten-dency to MPTP opening following reperfusion. Further, simultaneous stimulation of PKA & EPAC causes cardioprotection which is additive to the innate resistance.
REVIEW | doi:10.20944/preprints202111.0084.v1
Subject: Medicine And Pharmacology, Neuroscience And Neurology Keywords: Parkinson’s disease; gene therapy; mitochondria; genome editing
Online: 3 November 2021 (14:17:16 CET)
Background. Mitochondrial dysfunction has been identified as a pathophysiological hallmark of disease onset and progression in patients with Parkinsonian disorders. Besides the overall emergence of gene therapies in treating these patients, this highly relevant molecular concept has not yet been defined as a target for gene therapeutic approaches. Methods. This narrative review will discuss the experimental evidence suggesting mitochondrial dysfunction as a viable treatment target in patients with monogenic and idiopathic Parkinson’s disease. In addition, we will focus on general treatment strategies and crucial challenges which need to be overcome. Results. Our current understanding of mitochondrial biology in parkinsonian disorders opens up the avenue for viable treatment strategies in Parkinsonian disorders. Insights can be obtained from primary mitochondrial diseases. However, substantial knowledge gaps and unique challenges of mitochondria-targeted gene therapies need to be addressed to provide innovative treatments in the future. Conclusions. Mitochondria-targeted gene therapies are a potential strategy to improve an important primary disease mechanism in Parkinsonian disorders. However, further studies are needed to address the unique design challenges for mitochondria-targeted gene therapies.
REVIEW | doi:10.20944/preprints201907.0330.v1
Subject: Biology And Life Sciences, Plant Sciences Keywords: incompatibility; male sterility; mitochondria; somatic hybrid; recombination
Online: 29 July 2019 (05:21:51 CEST)
Plant male sterility refers to the failure in the production of fertile pollen. It occurs spontaneously in natural populations and may be caused by genes encoded in the nuclear (genic male sterility; GMS) or mitochondrial (cytoplasmic male sterility; CMS) genomes. This feature has great agronomic value for the production of hybrid seeds and has been widely used in crops, such as corn, rice, wheat, citrus, and several species of the family Solanaceae. Mitochondrial genes determining CMS have been uncovered in a wide range of plant species. The modes of action of CMS have been classified in terms of the effect they produce in the cell, which ultimately leads to a failure in the production of pollen. Male fertility can be restored by nuclear-encoded genes, termed restorer-of-fertility (Rf) factors. CMS from wild plants has been transferred to species of agronomic interest through somatic hybridization. Somatic hybrids have also been produced to generate CMS de novo upon recombination of the mitochondrial genomes of two parental plants or by separating the CMS cytoplasm from the nuclear Rf alleles
REVIEW | doi:10.20944/preprints201811.0024.v1
Subject: Biology And Life Sciences, Animal Science, Veterinary Science And Zoology Keywords: mitochondria; mitochondrial dynamics; fusion; fission; pluripotency; differentiation
Online: 2 November 2018 (06:05:44 CET)
Mitochondria are highly dynamic organelles that continuously change their shape. Their main function is ATP production; however, they are additionally involved in a variety of cellular phenomena, such as apoptosis, cell cycle, proliferation, differentiation, reprogramming, and aging. The change in mitochondrial morphology is closely related to the functionality of mitochondria. Normal mitochondrial dynamics are critical for cellular function, embryonic development, and tissue formation. Thus, defect in proteins involved in mitochondrial dynamics that control mitochondrial fusion and fission can affect cellular differentiation, proliferation, cellular reprogramming, and aging. Here we review the processes and proteins involved in mitochondrial dynamics and its various associated cellular phenomena.
REVIEW | doi:10.20944/preprints201807.0260.v1
Subject: Biology And Life Sciences, Cell And Developmental Biology Keywords: mitochondria; invertebrate; reactive oxygen species; oxidative phosphorylation
Online: 16 July 2018 (08:27:03 CEST)
Neurodegenerative diseases like Alzheimer’s disease (AD) are poised to become a global health crisis, and therefore understanding the mechanisms underlying the pathogenesis is critical for the development of therapeutic strategies. Mutations in genes encoding presenilin occur in most familial Alzheimer’s disease but the role of PSEN in AD is not fully understood. In this review, the potential modes of pathogenesis of AD are discussed, focusing on calcium homeostasis and mitochondrial function. Moreover, research using Caenorhabditis elegans to explore the effects of calcium dysregulation due to presenilin mutations on mitochondrial function, oxidative stress and neurodegeneration is explored.
ARTICLE | doi:10.20944/preprints201711.0147.v1
Subject: Biology And Life Sciences, Food Science And Technology Keywords: glycolysis; lipidome; meat; mitochondria; oxidation; proteome; turkey
Online: 23 November 2017 (03:11:04 CET)
A commercially reared domesticated turkey (Meleagris gallopavo) was purchased from a local market and sections of tissue representing leg, thigh, and breast were harvested and processed for analysis of the lipids and proteins present. Leg and thigh tissue was enriched in mitochondrial proteins whereas the breast tissue was enriched in glycolytic enzymes as well as the cytosolic and mitochondrial forms of glycerol-3-phosphate dehydrogenase. A potential marker for breast tissue muscle formation and/or function was also identified. The tissues could clearly be separated based upon their lipid profiles with little differences in cardiolipin levels suggesting that mitochondrial surface areas may be similar across the tissues. The most significant differences in the lipids were found to be higher levels of oxidized lipids in thigh meat. This work provides the first untargeted proteome and lipidome datasets for the domesticated turkey. The proteome dataset is accessible from ProteomeXchange Consortium via the PRIDE partner repository with the identifier PXD008207.
ARTICLE | doi:10.20944/preprints202311.1981.v1
Subject: Medicine And Pharmacology, Oncology And Oncogenics Keywords: Mitochondria; ROS; drug repurposing; oxidative phosphorylation; DNA damage
Online: 30 November 2023 (11:26:10 CET)
Breast cancer is a serious disease and the second leading cause of cancer-related death among women in the U.S. New treatments for this aggressive disease are urgently needed. Repurposing FDA-approved drugs for cancer treatment is an alternative that saves time and lowers the costs needed for drug development. In this study, we investigated the effects of proguanil, an anti-malarial drug, in breast cancer cells. Proguanil exhibited a significant cytotoxic effect on breast cancer cell lines including patient derived cell lines. Proguanil caused apoptosis through increased production of ROS and consequent decrease of mitochondrial membrane potential, mitochondrial respiration, and ATP production rates. ROS generation by proguanil was up to 3-fold higher when compared to the control. Proguanil treatment increased the expression of Bax, p-H2AX, cleaved-caspase 9, cleaved PARP, and down-regulated bcl-2 and survivin in breast cancer cell lines. The enlargement of 4T1 breast tumors in female Balb/c mice was suppressed by 55% through daily oral administration of 20mg/kg of proguanil. Western blot analyses of proguanil- treated tumors showed increased levels of p-H2AX, Bax, c-PARP, and c-caspase3 compared to control. Proguanil proved to be an efficient in vitro and in-vivo inhibitor of breast cancer cells, hence should be considered further for clinical investigation against breast cancer.
REVIEW | doi:10.20944/preprints202307.0156.v1
Subject: Biology And Life Sciences, Cell And Developmental Biology Keywords: stem-cell; differentiation; asymmetric; mitochondria; metabolism; epigenetic; RISP
Online: 4 July 2023 (07:50:23 CEST)
The study of the mechanisms underlying stem cell differentiation is under intensive research, and includes the contribution of a metabolic switch from glycolytic to oxidative metabolism. While mitochondrial biogenesis has been previously demonstrated in number of differentiation models, it is only recently that the role of mitochondrial dynamics has started to be explored. The discovery of asymmetric distribution of mitochondria in stem cell progeny has still strengthened the interest for the field. This review attempts to summarize the regulation of mitochondrial asymmetric apportioning by the mitochondrial fusion, fission and mitophagy processes, as well as to emphasize how asymmetric mitochondrial apportioning in stem cells affects their metabolism, and thus epigenetics, and determines cell fate.
ARTICLE | doi:10.20944/preprints202306.0208.v1
Subject: Medicine And Pharmacology, Pharmacology And Toxicology Keywords: cerebellum; edaravone; mitochondria; neurodegeneration; spinocerebellar ataxia type 1
Online: 2 June 2023 (14:01:57 CEST)
Edaravone is a mitochondrially targeted drug with a suggested capability to modify the course of diverse neurological diseases. Nevertheless, edaravone has not been tested yet in the context of spinocerebellar ataxia 1 (SCA1), an incurable neurodegenerative disease characterized mainly by cerebellar disorder with a strong contribution of inflammation and mitochondrial dysfunction. This study aimed to address this gap, exploring the potential of edaravone to slow down SCA1 progression in a mouse knock-in SCA1 model. SCA1154Q/2Q and healthy SCA12Q/2Q mice were getting either edaravone or saline daily for more than 13 weeks. The functional impairments were assessed via a wide spectrum of behavioral assays reflecting motor and cognitive deficits and behavioral abnormalities. Moreover, we used high-resolution respirometry to explore mitochondrial function, and immunohistochemical and biochemical tools to assess the magnitude of neurodegeneration, inflammation and neuroplasticity. Data were analyzed using (hierarchical) Bayesian regression models combined with the methods of multivariate statistics. Our analysis pointed out various previously documented neurological and behavioral deficits of SCA1 mice. However, we did not detect any plausible therapeutic effect of edaravone on either behavioral dysfunctions or other disease hallmarks in SCA1 mice. Thus, our results did not provide support for the therapeutic potential of edaravone in SCA1.
REVIEW | doi:10.20944/preprints202305.1072.v1
Subject: Biology And Life Sciences, Neuroscience And Neurology Keywords: cytoskeleton; microtubules; mitochondria, neuron, transport, TNTs, mitochondrial transplantation
Online: 16 May 2023 (03:50:58 CEST)
The highly specialized structure and function of neurons depend on a sophisticated organization of the cytoskeleton, which supports a similarly sophisticated system to traffic organelles and cargo vesicles. Mitochondria sustain crucial functions by providing energy and buffering calcium where is needed. Accordingly, the distribution of mitochondria is not even in neurons and is regulated by a dynamic balance between active transport and stable docking events. This system is finely tuned to respond to changes in environmental conditions and neuronal activity. In this review, we summarize the mechanisms by which mitochondria are selectively transported in different compartments taking into account the structure of the cytoskeleton, the molecular motors and the metabolism of neurons. Remarkably, the motor proteins driving the mitochondrial transport in axons have been shown to mediate also their transfer between cells. This so-named intercellular transport of mitochondria is opening new exciting perspectives in the treatment of multiple diseases.
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.
ARTICLE | doi:10.20944/preprints202301.0097.v1
Subject: Biology And Life Sciences, Plant Sciences Keywords: mitochondria; iron transporters; MIT; developmental defects; RNA-seq
Online: 5 January 2023 (03:42:32 CET)
Iron is the most abundant micronutrient in plant mitochondria and it has a crucial role in biochemical reactions involving electron transfer. It has been described in Oryza sativa that Mitochondrial Iron Transporter (MIT) is an essential gene and that knockdown mutant rice plants have a decreased amount of iron in mitochondria, strongly suggesting that OsMIT is involved in mitochondrial iron uptake. In Arabidopsis thaliana, two genes encode MIT homologues. In this study, we analyzed different AtMIT1 and AtMIT2 mutant alleles, confirming that individually AtMIT1 nor AtMIT2 genes are essential. When we generated crosses between Atmit1 and Atmit2 alleles we were able to isolate homozygous double mutant plants. Interestingly, homozygous double mutant plants were obtained only when mutant alleles of Atmit2 with the T-DNA insertion in the intron region were used for crossings, and in these cases a correctly spliced AtMIT2 mRNA was generated, although at a low level. Atmit1 Atmit2 double homozygous mutant plants, which were knockout for AtMIT1 and knockdown for AtMIT2, were grown and chacterised in iron sufficient conditions. Pleiotropic developmental defects were observed including abnormal seeds, increased number of cotyledons, slow growth rate, pinoid stems, defects in flower structures and reduced seed set. We observed a possible phenomenon of T-DNA suppression in the next generation of Atmit1 Atmit2 double homozygous mutant plants, correlating with an increased splicing of the AtMIT2 intron containing the T-DNA. Molecular analysis of gene expression markers for mitochondrial and oxidative stress showed that Atmit1 Atmit2 double homozygous mutant plants express a degree of mitochondrial perturbation. A RNA-Seq study was performed and we could identify more than 760 genes differentially expressed in Atmit1 Atmit2, including genes involved in iron transport, coumarin metabolism, and hormones metabolism, transport and signaling. Our data suggest that some of the phenotypes observed in Atmit1 Atmit2 double homozygous mutant plants are mediated by defects in auxin homeostasis.
ARTICLE | doi:10.20944/preprints202208.0182.v1
Subject: Medicine And Pharmacology, Oncology And Oncogenics Keywords: oncology; nutrition; supportive care; integrative oncology; metabolism; mitochondria
Online: 9 August 2022 (15:02:55 CEST)
Cancer-related fatigue is a common, burdensome symptom of cancer and side-effect of chemotherapy. While a Mediterranean Diet (MedDiet) promotes energy metabolism and overall health, its effects on cancer-related fatigue remain unknown. In a randomized controlled trial, we evaluated a rigorous MedDiet intervention for feasibility and safety as well as preliminary effects on cancer-related fatigue and metabolism compared to usual care. Participants had stage I-III cancer and at least 6 weeks of chemotherapy scheduled. After baseline assessments, randomization occurred 2:1, MedDiet:usual care. Measures were collected at baseline, week 4, and week 8 including MedDiet adherence, dietary intake, and blood-based metabolic measures. Mitochondrial respiration from freshly isolated T cells was measured at baseline and 4 weeks. Participants (n=33) were 51.0±14.6 years old, 94% were female, and 91% were being treated for breast cancer. The study was feasible, with 100% completing the study and >70% increasing their MedDiet adherence at 4 and 8 weeks compared to baseline. Overall, the MedDiet intervention vs. usual care had a small-moderate effect on change in fatigue at weeks 4 and 8. For those with a baseline MedDiet score<5 (n=21), the MedDiet intervention had a moderate-large effect of 0.67 and 0.48 at weeks 4 and 8, respectively. The MedDiet did not affect blood-based lipids, though it had a beneficial effect on fructosamine (ES= -0.55). Fatigue was associated with mitochondrial dysfunction including lower basal respiration, maximal respiration, and spare capacity (p<0.05 for FACIT-F fatigue subscale and BFI, usual fatigue). In conclusion, the MedDiet was feasible and attenuated cancer-related fatigue among patients undergoing chemotherapy, especially those with lower MedDiet scores at baseline.
REVIEW | doi:10.20944/preprints202205.0141.v1
Subject: Biology And Life Sciences, Biochemistry And Molecular Biology Keywords: Cigarette smoking; e-cigarette smoking; mitochondria; fusion; fission
Online: 10 May 2022 (12:54:42 CEST)
Toxins present in cigarette and e-cigarette smoke constitute a significant cause of illnesses and are known to have fatal health impacts. Specific mechanisms by which toxins present in smoke impair cell repair are still being researched and are of prime interest for developing more effective treatments. Current literature suggests toxins present in cigarette smoke and aerosolized e-vapor trigger abnormal intercellular responses, damage mitochondrial function, and consequently disrupt the homeostasis of the organelle’s biochemical processes by increasing reactive oxidative species. Increased oxidative stress sets off a cascade of molecular events, disrupting optimal mitochondrial morphology and homeostasis. Furthermore, smoking-induced oxidative stress may also amalgamate with other health factors to contribute to various pathophysiological processes. An increasing number of studies show that toxins may affect mitochondria even though exposure to secondhand or thirdhand smoke. This review assesses the impact of toxins present in tobacco smoke and e-vapor on mitochondrial health, networking, and critical structural processes including mitochondria fission, fusion, hyperfusion, fragmentation, and mitophagy. The efforts are focused on discussing current evidence linking toxins present in first, second, and thirdhand smoke to mitochondrial dysfunction
ARTICLE | doi:10.20944/preprints202203.0225.v1
Subject: Medicine And Pharmacology, Pharmacology And Toxicology Keywords: chemotherapy; muscle atrophy; Doxorubicin; mitochondria; reactive oxygen species
Online: 16 March 2022 (08:22:57 CET)
Doxorubicin (Dox) is a commonly used chemotherapeutic that can adversely affect skeletal muscle, including causing muscle atrophy. Dox is known to induce an event known as mitochondrial permeability transition (MPT) in cardiac muscle and this plays an important role in Dox-mediated cardiac toxicity. Further to this, recent evidence identifies MPT as a mechanism of atrophy in skeletal muscle, suggesting that MPT may underlie some of the Dox-related toxicity in skeletal muscle. To test this hypothesis, we used cultured human primary myotubes, C2C12 myotubes, and single adult mouse flexor digitorum brevis (FDB) muscle fibers in experiments involving Dox treatment with or without inhibitors of MPT. Dox treatment of myotubes caused myonuclear translocation of the mitochondrial protein apoptosis inducing factor (AIF) and increased mitochondrial reactive oxygen species (mROS), consistent with the known consequences of MPT. Furthermore, Dox caused atrophy in C2C12 myotubes grown on patterned plates, human primary myotubes, and single muscle fibers from adult mice. Notably, Dox-induced atrophy could be prevented by a wide variety of agents that inhibit MPT, as well as by inhibiting mROS or Caspase 3. In conclusion, our results indicate that MPT plays an important role in driving Dox-mediated skeletal muscle atrophy.
ARTICLE | doi:10.20944/preprints202111.0578.v1
Subject: Medicine And Pharmacology, Hematology Keywords: DPI; Mitochondria; Leukaemia; Oxidative stress; OxPhos; Ara-C
Online: 30 November 2021 (21:37:18 CET)
Acute myeloid leukaemia (AML) is characterized by the accumulation of undifferentiated blast cells in the bone marrow and blood. In most AMLs, relapse frequently occurs due to resistance to chemotherapy. Compelling research results indicate that drug resistance in cancer cells is highly dependent on the intracellular levels of reactive oxygen species (ROS). Modulating ROS levels is therefore a valuable strategy to overcome the chemotherapy resistance of leukemic cells. In this study, we evaluated the efficiency of diphenyleneiodonium (DPI), a well-known inhibitor of ROS production, in targeting AML cells. Results showed that although inhibiting cytoplasmic ROS production, DPI triggered an increase in the mitochondrial ROS levels caused by the disruption of the mitochondrial respiratory chain. We also demonstrated that DPI blocks the mitochondrial oxidative respiration (OxPhos) in a dose-dependent manner and that AML cells with high OxPhos status were highly sensitive to treatment with DPI, which synergizes with the chemotherapeutic agent cytarabine (Ara-C). Thus, our results suggest that targeting mitochondrial function by DPI might be exploited to target AML cells with high OxPhos status.
HYPOTHESIS | doi:10.20944/preprints202104.0606.v2
Subject: Biology And Life Sciences, Biophysics Keywords: Parkinson’s disease; alpha-synuclein; Lewy bodies; phase transition; thermodynamics; and mitochondria
Online: 10 January 2022 (12:23:19 CET)
I wish to suggest a physiological function for alpha-synuclein (a-syn) that has the potential to explain its role in pathology. Intraneuronal proteinaceous Lewy Bodies (LBs), the pathological hallmark of Parkinson’s disease and other synucleinopathies, consist majorly of a-syn. Ample evidence suggests that LBs are not the result of simple amyloidosis of cytosolic a-syn. Benign soluble unstructured a-syn gets converted into toxic species which preferentially accumulates in LBs. But how these aberrant a-syn molecules are produced in the cytosol, is still not clear. The present hypothesis is an effort to relate a metabolic reaction specific to neuronal function, that is, phase transition, with the pathobiology of a-syn. During high frequency stimulation, which entails rapid phase transition reactions at the presynaptic compartment, aberrant interaction of a-syn with the membrane occasionally generates toxic a-syn molecules. My conjecture is that the physiological function of a-syn is to modulate membrane fluidity by a process wherein it goes through a conformation cycle driven by a flux of energy from mitochondria. It is the range of toxic a-syn produced during aberrant phase transition reaction that is responsible for pathology, not the normal a-syn that reenters the conformation cycle, thereby, resolving the paradox of the Janus-face of a-syn.
ARTICLE | doi:10.20944/preprints202103.0655.v1
Subject: Biology And Life Sciences, Biochemistry And Molecular Biology Keywords: mitochondria; Ca2+ handling; heart failure; CaMKII; cardiomyocyte hypertrophy
Online: 26 March 2021 (10:41:00 CET)
Background : ATPase inhibitor factor-1 (IF1) preserves cellular ATP under conditions of respiratory collapse, yet the function of IF1 under normal respiring conditions is unresolved. We tested the hypothesis that IF1 promotes mitochondrial dysfunction and pathological cardiomyocyte hypertrophy in the context of heart failure (HF). Methods and results Cardiac expression of IF1 was increased in mice and in humans with HF, downstream of neurohumoral signaling pathways and in patterns that resembled the fetal-like gene program. Adenoviral expression of wild type IF1 in primary cardiomyocytes resulted in pathological hypertrophy and metabolic remodeling as evidenced by enhanced mitochondrial oxidative stress, reduced mitochondrial respiratory capacity, and the augmentation of extra-mitochondrial glycolysis. Similar perturbations were observed with an IF1 mutant incapable of binding to ATP-synthase (E55A mutation), indication that these effects occurred independent of binding to ATP synthase. Instead, IF1 promoted mitochondrial fragmentation and compromised mitochondrial Ca2+ handling, which resulted in sarcoplasmic reticulum Ca2+ overloading. The effects of IF1 on Ca2+ handling were associated with the cytosolic activation of CaMKII and inhibition of CaMKII or co-expression of catalytically dead CaMKIIδC was sufficient to prevent IF-1 induced pathological hypertrophy. Conclusions IF1 represents a novel member of the fetal-like gene program that contributes to mitochondrial dysfunction and pathological cardiac remodeling in HF. Furthermore, we present evidence for a novel, ATP-synthase independent, role for IF1 in mitochondrial Ca2+ handling and mitochondrial- to nuclear crosstalk involving CaMKII.
REVIEW | doi:10.20944/preprints202103.0043.v1
Subject: Biology And Life Sciences, Biochemistry And Molecular Biology Keywords: zinc, mitochondria, neurodegeneration, calcium, energy metabolism, mitochondrial dynamics
Online: 2 March 2021 (09:03:05 CET)
Zinc is a highly abundant cation in the brain, where it is essential for cellular function, including transcription, enzymatic activity, and cell signaling. However, zinc can also trigger injurious cascades in neurons, contributing to the pathology of neurodegenerative diseases. Mitochondria, critical for meeting the high energy demands of the central nervous system (CNS), are a principal target of the deleterious actions of zinc. An increasing body of work suggests that intracellular zinc, can, under certain circumstances, contribute to neuronal damage by inhibiting mitochondrial energy processes, including dissipation of the mitochondrial membrane potential, leading to ATP depletion. Additional consequences of zinc-mediated mitochondrial damage include reactive oxygen species (ROS) generation, mitochondrial permeability transition, and calcium deregulation. Zinc can also induce mitochondrial fission, resulting in mitochondrial fragmentation, as well as inhibition of mitochondrial motility. Here, we review the known mechanisms responsible for the deleterious actions of zinc on the organelle, within the context of neuronal injury associated with neurodegenerative processes. Elucidating the critical contributions of zinc-induced mitochondrial defects to neurotoxicity and neurodegeneration may provide insight into novel therapeutic targets in the clinical setting.
ARTICLE | doi:10.20944/preprints202009.0241.v1
Subject: Medicine And Pharmacology, Gastroenterology And Hepatology Keywords: prebiotic; oligosaccharides; gut microbiota; fatty liver; metabolism; mitochondria
Online: 11 September 2020 (04:17:52 CEST)
Understanding the importance of gut microbiota (GM) in non-alcoholic fatty liver disease (NAFLD) has raised the hope for therapeutic microbes. We have shown that high hepatic fat associated with low abundance of Faecalibacterium prausnitzii in humans and further, administration of F. prausnitzii prevented NAFLD in mice. Here, we aimed to target F. prausnitzii by prebiotic xylo-oligosaccharides (XOS) to treat NAFLD. First, the effect of XOS on F. prausnitzii growth was assessed in vitro. Then, XOS was supplemented or not with high (HFD) or low (LFD) fat-diet for 12-weeks in Wistar rats (n=10/group). XOS increased F. prausnitzii growth having only minor impact on the GM composition. When supplemented with HFD, XOS prevented hepatic steatosis. The underlying mechanisms involved enhanced hepatic β-oxidation and mitochondrial respiration. 1H-NMR analysis of caecal metabolites showed that compared to HFD, LFD group had healthier caecal short-chain fatty acid profile and the combination of HFD and XOS was associated with reduced caecal isovalerate and tyrosine, metabolites previously linked to NAFLD. Caecal branched-chain fatty acids associated positively and butyrate negatively with hepatic triglycerides. In conclusion, our study identifies F. prausnitzii as a possible target to treat NAFLD with XOS. The underlying preventive mechanisms involved improved hepatic oxidative metabolism.
ARTICLE | doi:10.20944/preprints202006.0352.v1
Subject: Biology And Life Sciences, Virology Keywords: SARS-CoV-2; ARDS; non-structural proteins; mitochondria
Online: 29 June 2020 (10:40:07 CEST)
Mitochondria are classically termed as powerhouse of a mammalian cell. Most of the cellular chemical energy in the form of adenosine tri phosphate (ATP) is generated by mitochondria and dysregulation of mitochondrial functions thus can be potentially fatal of cellular homeostasis and health. Acute respiratory distress has been earlier linked to mitochondrial dysfunction. SARS-CoV-2 infection severity leads to acute respiratory distress syndrome (ARDS) and can be fatal. We tried to investigate possible connection between SARS-CoV-2, ARDS and mitochondria. Here, we report identification of SARS-CoV-2 non-structural proteins (particularly Nsp12 and 13) that have recognition sequence with respect to mitochondrial entry. We also report that these proteins can potentially shuttle between cytoplasm and mitochondria based on the localization signals and help in downstream maintenance of the virus. Their properties to use ATP for enzymatic activities may cause ATP scavenging allowing viral RNA functions in lieu of host cell health.
REVIEW | doi:10.20944/preprints202002.0396.v1
Subject: Medicine And Pharmacology, Neuroscience And Neurology Keywords: Alzheimer's disease; sirtuins; mitochondria; leaky gut; inflammation; neuroimmune
Online: 27 February 2020 (10:52:33 CET)
Alzheimer's disease (AD) has been the subject of extensive investigation as to its biological underpinnings. However, this has produced little of therapeutic benefit or indeed provided any accepted biomarkers that could tailor treatment. This chapter reviews data on the main pathophysiologic processes that have been widely shown to be altered in AD, including circadian dysregulation, mitochondrial dysfunction, gut dysbiosis, and immune-glia-platelet activation. It is proposed that alterations in the gut microbiome, including gut dysbiosis and increased gut permeability drive changes in mitochondrial function that are intimately associated with significant variations in sirtuin expression. Both mitochondria-located and nucleus/cytoplasm located sirtuins can act on mitochondrial function in different cells and body systems to co-ordinate the ageing-associated changes that underpin AD. The sirtuins are therefore key aspect to a developmental model of AD that is more 'holistic' in perspective, thereby providing a framework for the detection of earlier biomarkers and more successful treatment for the heterogenous nature of AD pathoetiology.
ARTICLE | doi:10.20944/preprints201811.0563.v1
Subject: Biology And Life Sciences, Animal Science, Veterinary Science And Zoology Keywords: miR-125b-2; testis; PAP; reproduction; sperm; mitochondria
Online: 23 November 2018 (14:06:22 CET)
microRNAs can cause male infertility by impacting sperm quality and impaired spermatogenesis. Since the miR-125 family plays an important role in regulating embryo development, but the function of miR-125b-2 in male reproduction remains unknown. In this study, we prepared a model of miR-125b knockout (KO) mice. Among the KO mice, the progeny test showed that litter sizes decreased significantly and the rate of non-parous females increased significantly (p<0.05). At the same time, the testosterone concentration increased significantly (p<0.01), with the remarkable decrease for estradiol (p<0.05). Moreover, sperm count decreased obviously (p<0.05) and the percentage of abnormal sperms increased significantly (p<0.01). Testicular transcriptome sequencing demonstrated that there were 173 up-regulated genes, including Papolb (PAP), and 151 down-regulated genes in KO mice compared with wild type (WT). KEGG and GO analysis showed many of these genes were involved in sperm mitochondrial metabolism and other cellular biological processes. Meanwhile, the sperm mitochondria DNA (mtDNA) copy number was increased significantly (p<0.01) in KO mice, but the integrity of mtDNA and nuclear DNA (nDNA) had no change. In the top 10 up-regulated genes, as a testis specific expressing gene, PAP can affect the process of spermatogenesis. Western blotting and Luciferase Assay validated that PAP was the target of miR-125b-5p. Intriguingly, we also found that both miR-125b and PAP were only highly expressed in germ cells (GC) instead of Leydig cells (LC) and Sertoli cells (SC), and miR-125b-5p could target PAP to regulate TM3 cell secretion of testosterone (p<0.05). Our study firstly demonstrated that miR-125b-2 could regulate testosterone secretion by directly targeting PAP and increase sperm mtDNA copy number to affect semen quality. The study indicated that miR-125b-2 had a positive influence on the reproductive performance of animal and could be a potential therapeutic target for male infertility.
REVIEW | doi:10.20944/preprints201712.0008.v1
Subject: Biology And Life Sciences, Cell And Developmental Biology Keywords: mitochondria; mitophagy; transmitophgy; PGC1; mitofusin; DRP1; MIRO1; CD38
Online: 1 December 2017 (13:55:15 CET)
Mitochondria function to generate ATP and also play important roles in cellular homeostasis, signaling, apoptosis, autophagy, and metabolism. The loss of mitochondrial function results in cell death and various types of diseases. Therefore, quality control of mitochondria via intra- and intercellular pathways is crucial. Intracellular quality control consists of biogenesis, fusion and fission, and degradation of mitochondria in the cell, whereas intercellular quality control involves tunneling nanotubes and extracellular vesicles. In this review, we outline the current knowledge on the intra- and intercellular quality control mechanisms of mitochondria.
REVIEW | doi:10.20944/preprints201806.0302.v1
Subject: Biology And Life Sciences, Cell And Developmental Biology Keywords: cerebral ischemia, blood brain barrier, endothelial cells, impaired mitochondria, neurovascular unit, regenerative medicine, stem cell therapy, transfer of healthy mitochondria, vasculature
Online: 19 June 2018 (14:27:25 CEST)
Stroke remains a major cause of death and disability in the United States and around the world. Solid safety and efficacy profiles of novel stroke therapeutics have been generated in the laboratory, but most failed in clinical trials. Investigations into the pathology and treatment of the disease remain a key research endeavor in advancing scientific understanding and clinical applications. In particular, cell-based regenerative medicine, specifically stem cells transplantation, may hold promise as stroke therapy because grafted cells and their components may recapitulate the growth and function of the neurovascular unit, which arguably represents the alpha and omega of stroke brain pathology and recovery. Recent evidence has implicated mitochondria, organelles with a central role in energy metabolism and stress response, in stroke progression. Recognizing that stem cells offer a source of healthy mitochondria, potentially transferrable into ischemic cells, may provide a new therapeutic tool. To this end, deciphering cellular and molecular processes underlying dysfunctional mitochondria may reveal innovative strategies for stroke therapy. Here, we review recent studies capturing the intimate participation of mitochondrial impairment in stroke pathology, and showcase promising methods of healthy mitochondria transfer into ischemic cells, to critically evaluate the potential of mitochondria-based stem cell therapy for stroke.
ARTICLE | doi:10.20944/preprints202311.0735.v1
Subject: Biology And Life Sciences, Biochemistry And Molecular Biology Keywords: Transcriptomics; Candida tropicalis; isoespintanol; genetic dysregulation; mitochondria; cell wall
Online: 13 November 2023 (14:21:10 CET)
Candida tropicalis, an opportunistic pathogen, ranks among the primary culprits of invasive candidiasis, a condition notorious for its resistance to conventional antifungal drugs. The urgency to combat these drug-resistant infections has spurred the quest for novel therapeutic compounds, with a particular focus on those of natural origin. In this study, we set out to evaluate the impact of Isoespintanol (ISO), a monoterpene derived from Oxandra xylopioides, on the transcriptome of C. tropicalis. Leveraging transcriptomics, our research aimed to unravel the intricate transcriptional changes induced by ISO within this pathogen. Our differential gene expression analysis unveiled 186 differentially expressed genes (DEGs) in response to ISO, with a striking 85% of these genes experiencing upregulation. These findings shed light on the multifaceted nature of ISO's influence on C. tropicalis, spanning a spectrum of physiological, structural, and metabolic adaptations. The upregulated DEGs predominantly pertained to crucial processes, including ergosterol biosynthesis, protein folding, response to DNA damage, cell wall integrity, mitochondrial activity modulation, and cellular responses to organic compounds. Simultaneously, 27 genes were observed to be repressed, affecting functions such as cytoplasmic translation, DNA damage checkpoints, membrane proteins, as well as metabolic pathways like trans-methylation, trans-sulfuration, and trans-propylamine. These results underscore the complexity of ISO's antifungal mechanism, suggesting that it targets multiple vital pathways within C. tropicalis. Such complexity potentially reduces the likelihood of the pathogen developing rapid resistance to ISO, making it an attractive candidate for further exploration as a therapeutic agent. In conclusion, our study provides a comprehensive overview of the transcriptional responses of C. tropicalis to ISO exposure. The identified molecular targets and pathways offer promising avenues for future research and the development of innovative antifungal therapies to combat infections caused by this pathogenic yeast.
ARTICLE | doi:10.20944/preprints202311.0449.v1
Subject: Biology And Life Sciences, Life Sciences Keywords: Nemaline myopathy; actin polymerization; mitochondria; linoleic acid; L-carnitine
Online: 7 November 2023 (11:28:56 CET)
Nemaline myopathy (NM) is one of the most common forms of congenital myopathy and it is identified by the presence of "nemaline bodies" (rods) in muscle fibers by histopathological exam-ination. The most common forms of NM are caused by mutations in the ACTA1 (Actin Alpha 1) and NEB (Nebulin) genes. Clinical features include hypotonia and muscle weakness. Unfortunate-ly, there is no curative treatment and the pathogenetic mechanisms remains unclear. In this man-uscript, we examined the pathophysiological alterations in NM using dermal fibroblasts derived from patients with mutations in ACTA1 and NEB genes. Patients’ fibroblasts were stained with rhodamine phalloidin to analyze the polymerization of actin filaments by fluorescence microsco-py. We found that patients' fibroblasts showed incorrect actin filament polymerization compared to control fibroblasts. Actin filament polymerization defects was associated with mitochondrial dysfunction. Furthermore, we identified two mitochondrial boosting compounds, linoleic acid (LA) and L-carnitine (LCAR), that improved the formation of actin filaments in mutant fibro-blasts and corrected mitochondrial bioenergetics. Our results indicate that cellular models can be useful to study the pathophysiological mechanisms involved in NM and to find new potential therapies. Furthermore, targeting mitochondrial dysfunction with LA and LCAR can revert the pathological alterations in NM cellular models.
REVIEW | doi:10.20944/preprints202310.1953.v1
Subject: Biology And Life Sciences, Biochemistry And Molecular Biology Keywords: Hydrogen; gas medicine; antioxidant; mitochondria; Keap1-Nrf2; Nrf2 activator
Online: 31 October 2023 (03:00:32 CET)
The gas molecules O2, NO, H2S, CO, CH4 , have been increasingly used for medical purposes. Beside these gas molecules, H2, the smallest diatomic molecule in nature, has become a rising star in gas medicine in the past few decades. As a non-toxic and easily accessible gas, H2 has shown preventive and therapeutic effects on various diseases of the respiratory, cardiovascular, central nervous and other systems, but the mechanisms are still unclear and even controversial, especially the mechanism of H2 as a selective radical scavenger. Mitochondria are the main organelles regulating energy metabolism in living organisms, as well as the main organelle of reactive oxygen species generation and target. We propose that the protective role of H2 may be mainly dependent on its unique penetrating ability to everywhere of the cells to regulate mitochondrial homeostasis by activating the Keap1-Nrf2 phase II antioxidant system, rather than its direct free radical scavenging activity. In this review, we summarize the protective effects and focus on the mechanism of H2 as a mitochondria-targeting nutrient by activating the Keap1-Nrf2 system in different disease models, and wish to provide a more rational theoretical support for the medical applications of hydrogen.
REVIEW | doi:10.20944/preprints202308.1668.v1
Subject: Biology And Life Sciences, Biochemistry And Molecular Biology Keywords: penetrating cations; mitochondria; membrane; uncoupler; phospholipid bilayer; anti-cancer
Online: 24 August 2023 (03:48:51 CEST)
As mitochondria are negatively charged organelles, penetrating cations are used as a part of the chimeric molecules to deliver the specific compounds into mitochondria. However, unmodified penetrating cations affect different aspects of cellular physiology as well. In this review we have attempted to summarize the data about side effects of the commonly used natural (e.gberberine) and artificial (e.g. tetraphenylphosphonium, rhodamine, methylene blue) penetrating cations on cellular physiology. For instance, it was shown that such types of molecules can (1) facilitate proton transport across membranes; (2) react with redox groups of respiratory chain; (3) induce DNA damage; (4) interfere with pleiotropic drug resistance; (5) disturb membrane integrity (6) inhibit the enzymes. Also, the products of the biodegradation of penetrating cations can be toxic. As penetrating cations accumulate in mitochondria, their toxicity is mostly due to the mitochondrial damage. Mitochondria of certain types of cancer cells appear to be especially sensitive to penetrating cations. Here we discuss the molecular mechanisms of the toxic effects and the anti-cancer activity of the penetrating cations.
REVIEW | doi:10.20944/preprints202306.1948.v1
Subject: Biology And Life Sciences, Aging Keywords: Aging, mitochondria, membrane potential, permeability transition pore, C. elegans
Online: 28 June 2023 (07:06:20 CEST)
It is widely reported that the mitochondrial membrane potential, ∆Ψm, is reduced in aging animals. It was recently suggested that the lower ∆Ψm in aged animals modulate mitochondrial bioenergetics and that this effect is a major cause of aging since artificially increased ∆Ψm in C. elegans increased lifespan. Here I review, critically, studies that reported reduction of ∆Ψm in aged animals, including worms, and conclude that many of these observations are best interpreted as evidence that the fraction of depolarized mitochondria is increased in aged cells because of the enhanced activation of the mitochondrial Permeability Transition Pore, mPTP. Activation of the voltage-gated mPTP depolarizes the mitochondria, inhibits oxidative phosphorylation, releases large amounts of calcium and mROS, and depletes cellular NAD+, thus accelerating degenerative diseases and aging. Since the inhibition of mPTP was shown to restore ∆Ψm and retard aging, the reported lifespan extension by artificially generated ∆Ψm in C. elegans is best explained by inhibition of the voltage-gated mPTP. Similarly, the reported activation of the mitochondrial Unfolded Protein Response by reduction of ∆Ψm, and the reported preservation of ∆Ψm in dietary restriction treatment in C. elegans are best explained as a resulting from activation or inhibition of the voltage-gated mPTP, respectively.
ARTICLE | doi:10.20944/preprints202212.0304.v2
Subject: Biology And Life Sciences, Biology And Biotechnology Keywords: Mitochondria; Co-translational import; BioID; Protein identification; Mass spectrometry
Online: 21 April 2023 (09:03:58 CEST)
Biotin-based proximity labeling approaches, such as BioID, have demonstrated their use for the study of mitochondria proteomes in living cells. The use of genetically engineered BioID cell lines enables the detailed characterization of poorly characterized processes such as mitochondrial co-translational import. In this process, translation is coupled to the translocation of the mitochon-drial proteins, alleviating the energy cost typically associated with the post-translational import relying on chaperone systems. However, the mechanisms are still unclear with only few actors identified but none that have been described in mammals yet. We thus profiled the TOM20 prox-isome using BioID, assuming that some of identified proteins could be molecular actors of the co-translational import in human cells. The obtained results showed a high enrichment of RNA bind-ing proteins close to the TOM complex. However, for the few selected candidates, we could not demonstrate a role in the mitochondrial co-translational import process. Nonetheless, we were able to demonstrate additional uses of our BioID cell line. Indeed, the experimental approach used in this study is thus proposed for the identification of mitochondrial co-translational import effec-tors and for the monitoring of protein entry inside mitochondria with a potential application in the prediction of mitochondrial protein half-life.
ARTICLE | doi:10.20944/preprints202302.0161.v1
Subject: Biology And Life Sciences, Cell And Developmental Biology Keywords: translocator protein 18 kDa; mitochondria; inflammation; CRISPR/Cas9; respirometry
Online: 9 February 2023 (09:25:55 CET)
Microglia are the resident immune cells of the central nervous system. Upon stimulus presentation microglia polarize from a resting to an activated state. Microglial translocator protein 18 kDa (TSPO) is considered as a marker of inflammation. Here, we characterized the role of TSPO by investigating the impact of TSPO deficiency on human microglia. We used TSPO knockout (TSPO-/-) variants of the human C20 microglia cell line. We found a significant reduction in the TSPO-associated protein VDAC1 in TSPO-/- compared to control cells. Moreover, we assessed the impact of TSPO deficiency on calcium levels and the mitochondrial membrane potential. Cytosolic and mitochondrial calcium concentrations were increased in TSPO-/- cell lines, whereas the mitochondrial membrane potential tended to be lower. Assessment of the mitochondrial DNA copy number via RT-PCR revealed a decreased amount of mtDNA in the TSPO-/- cells when compared to controls. Moreover, metabolic profiles of C20 cells were strongly dependent on the glycolytic pathway. However, TSPO depletion did not affect the cellular metabolic profile. Measurement of the mRNA expression levels of the pro-inflammatory mediators revealed an attenuated response to proinflammatory stimuli in TSPO-depleted cells, implying a role of the TSPO protein in the process of microglial polarization.
ARTICLE | doi:10.20944/preprints202210.0025.v1
Subject: Biology And Life Sciences, Biochemistry And Molecular Biology Keywords: mitochondria; Type 2 diabetes; MDP; MOTS-c; Humanin; SHLP
Online: 5 October 2022 (03:43:17 CEST)
Since the discovery of mitochondrial-derived peptides (MDP), their participation in cellular metabolism is no longer considered as the sole function of the mitochondria, but importance was also attached to its role as a source of protective factors of metabolic stress. These peptides are encoded in the mitochondrial genome and translated into the mitochondria or cytoplasm, to signal within the cell or be released and bind to membrane receptors. The objective of this work was explored and compare the frequency of MT-RNR1 and MT-RNR2 variants in sequences obtained from T2D individuals and control population. 213 different mitochondrial polymorphisms previously reported in the literature associated with T2D and cardiovascular diseases were analyzed. We can found three variants in the MT-RNR1 not related with MOTS-c coding sequence: m.1189T>C (rs28358571), m.1420T>C (rs111033356), and m.1438A>G (rs2001030); and secondly, three polymorphisms associated to MT-RNR2 m.2667T>C (rs878870626) related to humanin, m.1811A>G (rs28358576) in SHPL3 and m.3027T>C (rs199838004) in SHPL6 associated with statistical differences between the T2D and control group. All these findings were previously related to cardiovascular complications in literature and, as far as we know, relating for the first time in diabetic patients.
COMMUNICATION | doi:10.20944/preprints202201.0087.v1
Subject: Biology And Life Sciences, Cell And Developmental Biology Keywords: COVID-19; SARS-CoV-2 RNA; mitochondria; placenta; padlock
Online: 6 January 2022 (12:35:00 CET)
The ongoing COVID-19 pandemic dictated new priorities in biomedicine research. Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), the causative agent of COVID-19, is a single-stranded positive-sense RNA virus. In this pilot study, we optimized our padlock assay to visualize genomic/subgenomic regions using formalin-fixed paraffin-embedded placental samples obtained from a confirmed case of COVID-19. SARS-CoV-2 RNA was localized in trophoblastic cells. We also checked the presence of the virion by immunolocalization of its glycoprotein spike. In addition, we imaged mitochondria of placental villi keeping in mind that the mitochondrion has been suggested as a potential residence of the SARS-CoV-2 genome. Indeed, we observed a substantial overlapping of SARS-CoV-2 RNA and mitochondria in trophoblastic cells. This intriguing linkage correlated with an aberrant mitochondrial network. Overall, to our knowledge, this is the first study that provides the evidence of a co-localization of the SARS-CoV-2 genome and mitochondria in SARS-CoV-2 infected tissue. These findings also support the notion that SARS-CoV-2 infection could reprogram mitochondrial activity in highly specialized maternal/fetal interface.
REVIEW | doi:10.20944/preprints202106.0657.v1
Subject: Biology And Life Sciences, Anatomy And Physiology Keywords: mitochondria, dynamics, transport, mitophagy, cell proliferation, stemness, fate acquisition
Online: 28 June 2021 (13:55:59 CEST)
Mitochondria are essential to cell homeostasis, and alterations in mitochondrial distribution, segregation or turnover have been linked to complex pathologies such as neurodegenerative diseases or cancer. Understanding how these functions are coordinated in specific cell types is a major challenge to discover how mitochondria globally shape cell functionality. In this review, we will first describe how mitochondrial transport and dynamics are regulated throughout the cell cycle in yeast and in mammals. Second, we will explore the functional consequences of mitochondrial transport and partitioning on cell proliferation, fate acquisition, stemness, and on the way cells adapt their metabolism. Last, we will focus on how mitochondrial clearance programs represent a further layer of complexity for cell differentiation, or in the maintenance of stemness. Defining how mitochondrial transport, dynamics and clearance are mutually orchestrated in specific cell types may help our understanding of how cells can transition from a physiological to a pathological state.
ARTICLE | doi:10.20944/preprints202009.0014.v1
Subject: Chemistry And Materials Science, Nanotechnology Keywords: mitochondria, F0F1-ATPase, carbon nanotubes, computational nanotoxicology.; QSAR; NanoQSAR
Online: 1 September 2020 (11:49:20 CEST)
Herein, we present a combination of experimental and computational study on the mitochondrial F0F1-ATPase nanotoxicity inhibition induced by single-walled carbon nanotubes (SWCNT-pristine, SWCNT-COOH). To this end, the in vitro inhibition responses in submitochondrial particles (SMP) as F0F1-ATPase enzyme were strongly dependent on the concentration assay (from 3 to 5 µg/ml) for both types of carbon nanotubes. Besides, both SWCNTs show an interaction inhibition pattern like the oligomycin A (the specific mitochondria F0F1-ATPase inhibitor). Furthermore, the best crystallography binding pose obtained for the docking complexes based on the free energy of binding (FEB), fit well with the previous in vitro evidences from the thermodynamics point of view. Following an affinity order as: FEB (oligomycin A/F0-ATPase complex) = -9.8 kcal/mol > FEB (SWCNT-COOH/F0-ATPase complex) = - 6.8 kcal/mol ~ FEB (SWCNT-pristine complex) = -5.9 kcal/mol. With predominance of van der Waals hydrophobic nanointeractions with key F0-ATPase binding site residues (Phe 55 and Phe 64). By the other hand, results on elastic network models, and fractal-surface analysis suggest that SWCNTs induce significant perturbations by triggering abnormal allosteric responses and signals propagation in the inter-residue network which could affect the substrate recognition ligand geometrical specificity of the F0F1-ATPase enzyme in order (SWCNT-pristine > SWCNT-COOH). Besides, the performed Nano-QSTR models for both SWCNTs show that this method may be used for the prediction of the nanotoxicity induced by SWCNT. Overall, the obtained results may open new avenues toward to the better understanding and prediction of new nanotoxicity mechanisms, rational drug-design based nanotechnology, and potential biomedical application in precision nanomedicine.
ARTICLE | doi:10.20944/preprints201904.0277.v1
Subject: Biology And Life Sciences, Biochemistry And Molecular Biology Keywords: CREB; cryotherapy; gene expression; icing; mitochondria; Pgc-1α; transcription
Online: 25 April 2019 (08:07:44 CEST)
Local cryotherapy is widely used as a treatment for sports-related skeletal muscle injury. However, its molecular mechanisms are unknown. To clarify these mechanisms, in this study, we applied one to three 15-min cold stimulations at 4 °C to various cell lines (in vitro), the tibialis anterior (TA) muscle (ex vivo), and mouse limbs (in vivo). In the in vitro assay, cAMP response element-binding protein 1 (CREB1) was markedly phosphorylated (as pCREB1) and CREB-binding protein (CBP) was recruited to pCREB-1 in response to two or three cold stimulations. In a reporter assay with the cAMP-responsive element, the signals significantly increased after two to three cold stimulations at 4 °C. In the ex vivo study, CREB-targeting genes were significantly upregulated following two or three cold stimulations. The in vivo experiment disclosed that cold stimulation of a mouse limb for 9 days significantly increased mitochondrial DNA copy number and upregulated genes such as Pgc-1α involved in mitochondrial biogenesis. The foregoing results suggest that local cryotherapy increases CREB transcription and upregulates CREB-targeting genes in a manner dependent on cold stimulation frequency and duration. This information may serve as an impetus for further investigations into local cryotherapy as a treatment for sports-related skeletal muscle trauma.
ARTICLE | doi:10.20944/preprints201810.0342.v1
Subject: Biology And Life Sciences, Anatomy And Physiology Keywords: 4-octylphenol; male sertoli cells; reproductive toxicity; apoptosis; mitochondria
Online: 16 October 2018 (08:35:47 CEST)
The toxic effects of 4-octylphenol (4-OP) have been studied in species such as mouse and fish; however, the toxic effects of 4-OP in male specific niche cells has not been researched. In this study, we investigated the molecular mechanism of toxicity of 4-OP in mouse TM4 Sertoli cells. TM4 cells were treated with four concentrations (0, 10, 30, and 50 µM/mL) of 4-OP at time points 24, 48, and 72 h. Cell viability and apoptosis assay was conducted following exposure. 4-OP significantly decreased cell viability in a concentration- and time-dependent manner, and increased apoptosis. Quantitative PCR analysis showed that Bad, Bax, and Bak mRNA expression levels were higher in exposed cells than in the control, but Bcl-2 expression was decreased. Western blotting revealed that 4-OP induced activities of caspase-3 and phosphorylation of Bad in a concentration- and time-dependent manner. Additionally, cytochrome C protein did not colocalize with mitochondria marker dye by 24 h. Cytochrome c protein expression increased in a time-dependent manner with 50 µM/mL. These results suggest that 4-OP induces mitochondria-mediated apoptosis by regulation of Bcl-2 family proteins and caspase-3 activation in male Sertoli cells.
ARTICLE | doi:10.20944/preprints201805.0211.v1
Subject: Biology And Life Sciences, Anatomy And Physiology Keywords: gap junction; connexin; annular gap junction vesicle; mitochondria; lysosome
Online: 15 May 2018 (08:39:33 CEST)
It is becoming clear that in addition to gap junctions, playing a role in cell-cell communication, gap junction proteins, connexins, located in cytoplasmic-compartments may have other important functions. Mitochondrial connexin 43 (Cx43) is increased after ischemic preconditioning and has been suggested to play a protective role in the heart. How Cx43 traffics to the mitochondria and the interactions of mitochondria with other Cx43-containing structures are unknown. In this study, immunocytochemical, super-resolution and transmission electron microscopy were used to detect cytoplasmic Cx43-containing structure and to demonstrate their interactions with other cytoplasmic organelles. The most prominent cytoplasmic Cx43-containing structures, annular gap junctions, were demonstrated to form intimate associations with lysosomes as well as with mitochondria. Surprisingly, the frequency of associations between mitochondria and annular gap junctions was greater than that between lysosomes and annular gap junctions. The benefits of annular gap junction/mitochondrial associations are not known. However, it is tempting to suggest that the contact between annular gap junction vesicles and mitochondria facilitates Cx43 deliver to the mitochondria. Furthermore, it points to the need for investigating trafficking of Cx43 to cytoplasmic compartments and annular gap junction as more than only a vesicle destined for degradation.
ARTICLE | doi:10.20944/preprints202308.0380.v1
Subject: Biology And Life Sciences, Neuroscience And Neurology Keywords: CCCP, Carbonyl Cyanide m Chlorophenyl Hydrazone; calcium; Orai1; STIM1; mitochondria
Online: 4 August 2023 (12:39:11 CEST)
A major route for influx of calcium ions into neurons uses the STIM-Orai1 voltage-independent channel. Once cytosolic calcium ([Ca2+]i) elevates, it activates mitochondrial and endoplasmic calcium stores, to affect downstream molecular pathways. In the present study we employed a novel drug, Carbonyl Cyanide Chlorophenylhydrazone (CCCP), a mitochondrial uncoupler, to explore the role of mitochondria in cultured neuronal morphology. CCCP caused a sustained elevation of [Ca2+]i and, quite surprisingly, a massive increase in density of dendritic filopodia and spines in the affected neurons. This morphological change can be prevented in cultures ex-posed to calcium-free medium, to Orai1 antagonist 2APB, or to cells transfected with domi-nant-negative Orai1 plasmid. It is suggested that CCCP activates mitochondria through influx of calcium, to cause a rapid growth of dendritic processes
ARTICLE | doi:10.20944/preprints202306.0695.v1
Subject: Medicine And Pharmacology, Medicine And Pharmacology Keywords: Autophagy; Cancer; Chemotherapy; Homeostasis; Hydroxychloroquine; Mitochondria; Oxidative Stress; Rapamycin; Therapeutics
Online: 9 June 2023 (09:31:12 CEST)
Neuroblastoma is the most common tumour in children under 1 year old, accounting for approximately 50% of infant cancer cases. Although current treatments are relatively efficacious against this cancer, associated adverse effects could be detrimental to growth and development. In contrast, glioblastoma accounts for 52% of brain tumours and has an extremely poor prognosis. Current chemotherapeutics include temozolomide, which has numerous negative side-effects and a low-effective rate. Previous studies have shown the manipulation of autophagy to be a promising method for targeting cancers, including glioblastoma. We sought to determine the effects of autophagic alterations in combination with current chemotherapies in both neuroblastoma and glioblastoma. Supplementing cisplatin or temozolomide with autophagy activator rapamycin stabilized cancer cell mitochondria, despite having little effect on apoptosis or oxidative stress. Autophagy inhibition via 3-methyladenine or hydroxychloroquine alongside standard chemotherapies enhanced apoptosis and oxidative stress, with 3-methyladenine also disrupting mitochondrial health. Importantly, combining hydroxychloroquine with 0.5 µM cisplatin or 50 µg/mL temozolomide was as or more effective than 2 µM cisplatin or 100 µg/mL temozolomide alone. Analyzing these interesting results, a combined treatment of autophagy inhibitor with a standard chemotherapeutic agent could help to improve patient prognosis and reduce chemotherapy doses and their associated side-effects.
REVIEW | doi:10.20944/preprints202304.0098.v2
Subject: Medicine And Pharmacology, Neuroscience And Neurology Keywords: Alzheimer’s disease; Parkinson’s disease; mitochondria; oxidative stress; calcium; heterocyclic compounds
Online: 17 May 2023 (14:13:20 CEST)
Alzheimer’s disease (AD) and Parkinson’s disease (PD) are the two most common neurodegenerative diseases in elderly. The key histopathological features of these diseases are the presence of abnormal protein aggregates and the progressive and irreversible loss of neurons in specific brain regions. The exact mechanisms underlying the etiopathogenesis of AD or PD remain unknown, but there is extensive evidence indicating that excessive generation of reactive oxygen species (ROS) and reactive nitrogen species (RNS) along with a depleted antioxidant system, mitochondrial dysfunction, and intracellular Ca2+ dyshomeostasis play a vital role in the pathophysiology of these neurological disorders. Due to an improvement in life expectancy, the incidence of age-related neurodegenerative diseases has significantly increased. However, there is no effective protective treatment or therapy available but rather only very limited palliative treatment. Therefore, there is an urgent need for the development of preventive strategies and disease-modifying therapies to treat AD/PD. Because dysregulated Ca2+ metabolism drives oxidative damage and neuropathology in these diseases, the identification or development of compounds capable of restoring Ca2+ homeostasis and signaling may provide a neuroprotective avenue for the treatment of neurodegenerative diseases. In addition, a set of strategies to control mitochondrial Ca2+ homeostasis and signaling has been reported, including decreased Ca2+ uptake through voltage-operated Ca2+ channels (VOCCs). In this article, we review the modulatory effects of several heterocyclic compounds on Ca2+ homeostasis and trafficking, and their ability to regulate compromised mitochondrial function and associated free radical production during the onset and progression of AD or PD. This comprehensive review also describes the chemical synthesis of the heterocycles and summarizes the clinical trial outcomes.
REVIEW | doi:10.20944/preprints202303.0484.v1
Subject: Medicine And Pharmacology, Neuroscience And Neurology Keywords: movement disorders; mitochondria; energy metabolism; synaptic plasticity; basal ganglia; calcium
Online: 28 March 2023 (10:23:10 CEST)
Much evidence suggests a correlation between degeneration and mitochondrial impairment. Typical cases of degeneration can also be observed in physiological phenomena (aging) as well as in neurological neurodegenerative diseases and cancer. All these pathologies have as a common denominator the dyshomeostasis of mitochondrial bioenergy. Even neurodegenerative diseases show a bioenergetics imbalance in their pathogenesis or progression. Huntington's chorea and Parkinson's disease are both neurodegenerative diseases, but while Huntington's disease is a genetic, and progressive disease with early manifestation and severe penetrance, Parkinson's disease is a pathology with a multifactorial aspect. Indeed, there are different types of Parkinson/Parkinsonism. Many forms are early onset diseases linked to gene mutation, others can appear in young adults and senescent only post-injury, and a final group is idiopathic. Huntington's was defined as a hyperkinetic disorder, while Parkinson's is a hypokinetic disorder; but in the middle, there are a lot of similarities as well as neuronal excitability, the loss of striatal function, psychiatric comorbidity, etc. In the review, we would embrace the theories that both diseases start and develop in light of mitochondrial dysfunction. These dysfunctions act on energy metabolism and reduce the vitality of neurons in many different brain areas.
REVIEW | doi:10.20944/preprints202302.0015.v1
Subject: Biology And Life Sciences, Endocrinology And Metabolism Keywords: movement disorders; mitochondria; energy metabolism; synaptic plasticity; basal ganglia; calcium
Online: 1 February 2023 (11:53:47 CET)
Much evidence suggests a correlation between degeneration and mitochondrial impairment. Typical cases of degeneration can also be observed in physiological phenomena (aging) as well as in neurological neurodegenerative diseases and cancer. All these pathologies have as a common denominator the dyshomeostasis of mitochondrial bioenergy. Even neurodegenerative diseases show a bioenergetics imbalance in their pathogenesis or progression. Huntington's chorea and Parkinson's disease are both neurodegenerative diseases, but while Huntington's disease is a genetic, and progressive disease with early manifestation and severe penetrance, Parkinson's disease is a pathology with a multifactorial aspect. Indeed, there are different types of Parkinson/Parkinsonism. Many forms are early onset diseases linked to gene mutation, others can appear in young adults and senescent only post-injury, and a final group is idiopathic. Huntington's was defined as a hyperkinetic disorder, while Parkinson's is a hypokinetic disorder; but in the middle, there are a lot of similarities as well as neuronal excitability, the loss of striatal function, psychiatric comorbidity, etc. In the review, we would embrace the theories that both diseases start and develop in light of mitochondrial dysfunction. These dysfunctions act on energy metabolism and reduce the vitality of neurons in many different brain areas.
REVIEW | doi:10.20944/preprints202211.0032.v1
Subject: Medicine And Pharmacology, Neuroscience And Neurology Keywords: Alzheimer’s disease; Quantum Dot Nanoparticles; PINK1; Theranostic; mitochondria; drug delivery
Online: 1 November 2022 (14:29:26 CET)
One of the most frequent brain diseases, Alzheimer's is defined by poor cognitive function brought on by the build-up of Beta Amyloid plaques and the gradual death of neurons. Glucose metabolism and the development of amyloid plaques are being studied together. Under physiologically normal circumstances, glucose is the primary substrate for the adult human brain. The prodromal phases of AD are significantly influenced by glucose hypometabolism. Hypometabolism of glucose in the brain is a clear sign of mitochondrial dysfunction and bioenergetic system impairment. By regulating energy synthesis and cell death, mitochondria play a crucial role in the functioning of cells. Increased formation of reactive oxygen species (ROS) and oxidative stress are a result of mitochondrial dysfunction, which also accelerates the development of Alzheimer's disease. For the maintenance of balance, autophagy is crucial because it selectively destroys damaged mitochondria. AD affects this route for mitochondrial breakdown. Targeting specific mitochondrial ligands by interventions along this pathway might be a useful therapeutic approach. Due to a number of biological obstacles, this method has significant limitations. As a result, many nanocarriers have been created to improve drug delivery effectiveness. All potential nanotechnology-based treatments for AD have been examined in this study, with a particular emphasis on medication delivery to the mitochondria
ARTICLE | doi:10.20944/preprints202207.0152.v1
Subject: Biology And Life Sciences, Cell And Developmental Biology Keywords: Alzheimer’s disease; oxidative stress; presenilin; mitochondria; calcium; neuronal dysfunction; Nrf2
Online: 11 July 2022 (08:03:08 CEST)
A Mitochondrial dysfunction and oxidative stress are major contributors to the pathophysiology of neurodegenerative diseases, including Alzheimer’s disease (AD). However, the mechanisms driving mitochondrial dysfunction and oxidative stress are unclear. Familial AD (fAD) is an early onset form of AD caused primarily by mutations in the presenilin-encoding genes. Previously, using Caenorhabditis elegans as a model system to study presenilin function, we found that loss of C. elegans presenilin orthologue, SEL-12, results in elevated mitochondrial and cytosolic calcium levels. Here, we provide evidence that elevated neuronal mitochondrial generated reactive oxygen species (ROS) and subsequent neurodegeneration in sel-12 mutants are a consequence of the increase of mitochondrial calcium levels and not cytosolic calcium levels. We also identify mTORC1 signaling as a critical factor in sustaining high ROS in sel-12 mutants in part through its repression of the ROS scavenging system SKN-1/Nrf. Our study reveals that SEL-12/presenilin loss disrupts neuronal ROS homeostasis by increasing mitochondrial ROS generation and elevating mTORC1 signaling, which exacerbates this imbalance by suppressing SKN-1/Nrf antioxidant activity.
ARTICLE | doi:10.20944/preprints202107.0356.v1
Subject: Biology And Life Sciences, Anatomy And Physiology Keywords: airway cell exosomes; viral infection; microglia; mitochondria; reactive oxygen species
Online: 15 July 2021 (11:12:49 CEST)
Viral infections induce exosomes containing viral material and inflammatory factors. During respiratory tract infection, exosomes can easily cross the blood-brain barrier and transmit the inflammatory signal to the brain; however, such a hypothesis has no experimental evidence. The study investigated whether exosomes from virus mimetic poly (I:C)-primed airway cells enter the brain and interact with brain immune cells microglia. Airway cells were isolated from Wistar rats and BALB/c mice; microglial cell cultures - from Wistar rats. Exosomes from poly (I:C)-stimulated airway cell culture medium were isolated by precipitation, visualised by transmission electron microscopy, and evaluated by nanoparticle analyser; exosomal markers CD81 and CD9 were determined by ELISA. For in vitro and in vivo tracking, exosomes were loaded with Alexa Fluor 555-labelled RNA. Intracellular reactive oxygen species (ROS) were evaluated by DCFDA fluo-rescence and mitochondrial superoxide - by MitoSOX. The exosomes from poly (I:C)-primed airway cells entered the brain within an hour after intranasal introduction, were internalised by microglia, and induced intracellular and intramitochondrial ROS production. There was no ROS increase in microglial cells was after treatment with exosomes from airway cells untreated with poly (I:C). The data indicate that virus-primed airway cell exosomes might enter the brain and induce the activation of microglial cells.
ARTICLE | doi:10.20944/preprints202104.0564.v1
Subject: Biology And Life Sciences, Cell And Developmental Biology Keywords: Dendritic cell; Rapamycin; Mitochondria; Acute kidney injury; Ischemic Reperfusion Injury
Online: 21 April 2021 (09:13:27 CEST)
Dendritic cells (DCs) are unique immune cells that can link innate and adaptive immune responses and Immunometabolism greatly impacts their phenotype. Rapamycin is a macrolide compound that has immunosuppressant functions and is used to prevent graft loss in kidney transplantation. The current study evaluated the therapeutic potential of ex-vivo Rapamycin treated DCs to protect kidneys in a mouse model of acute kidney injury (AKI). For the Rapamycin single (S) treatment (Rapa-S-DC), Veh-DCs were treated with Rapamycin (10 ng/ml) for 1 hour before LPS. In contrast, Rapamycin multiple (M) treatment (Rapa-M-DC) were exposed to 3 treatments over 7 days. Only multiple ex-vivo Rapamycin treatments of DCs induced a persistent reprogramming of mitochondrial metabolism. These DCs had 18-fold more mitochondria, had almost 4-fold higher oxygen consumption rates, and produced more ATP compared to Veh-DCs (Veh treated control DCs). Pathway analysis showed IL10 signaling as a major contributing pathway to the altered immunophenotype after Rapamycin treatment compared to vehicle with significantly lower cytokines Tnfa, Il1b, and Il6, while regulators of mitochondrial content Pgc1a, Tfam, and Ho1 remained elevated. Critically, adoptive transfer of Rapamycin treated DCs to WT recipients 24 hrs before bilateral kidney ischemia significantly protected the kidneys from injury with a significant 3-fold improvement in kidney function. Last, the infusion of DCs containing higher mitochondria numbers (treated ex-vivo with healthy isolated mitochondria (10 µg/ml) one day before) also partially protected the kidneys from IRI. These studies demonstrate that pre-emptive infusion of ex-vivo reprogrammed DCs that have higher mitochondria content has therapeutic capacity to induce an anti-inflammatory regulatory phenotype to protect kidneys from injury.
Subject: Medicine And Pharmacology, Immunology And Allergy Keywords: Mitochondria; cytochrome c oxidase; COX4-1; COX4-2; HIF-1α
Online: 10 February 2021 (10:58:33 CET)
Cytochrome-c-oxidase (COX) subunit 4 (COX4) plays important roles in the function, assembly and regulation of COX (mitochondrial respiratory complex 4), the terminal electron acceptor of the oxidative phosphorylation (OXPHOS) system. The principal COX4 isoform, COX4-1, is expressed in all tissues, whereas COX4-2 is mainly expressed in the lungs, or under hypoxia and other stress conditions. We have previously described a patient with a COX4-1 defect with a relatively mild presentation compared to other primary COX deficiencies, and hypothesized that this could be the result of compensatory upregulation of COX4-2. To this end, COX4-1 was downregulated by shRNAs in human foreskin fibroblasts (HFF), and compared to patient's cells. COX4-1, COX4-2 and HIF-1α were detected by immunocytochemistry. The mRNA transcripts of both COX4 isoforms and HIF-1 target genes were carried out by RT-qPCR. COX activity and OXPHOS function were measured by enzymatic and oxygen consumption assays, respectively. Pathways were analyzed by CEL-Seq2 and by RT-qPCR. We demonstrate elevated COX4-2 levels in the COX4-1-deficient cells with a concomitant HIF-1α stabilization, nuclear localization and upregulated hypoxia and glycolysis pathways. We suggest that COX4-2 and HIF-1α has the are upregulated, also in normoxia as a compensatory mechanism in COX4-1 deficiency.
HYPOTHESIS | doi:10.20944/preprints202006.0038.v1
Subject: Medicine And Pharmacology, Oncology And Oncogenics Keywords: T-lymphocytes; programmed cell death protein-1; mitochondria; adenosine triphosphate
Online: 4 June 2020 (13:54:40 CEST)
It has been demonstrated that a decrease in cellular adenosine triphosphate (c-ATP) causes cellular dysfunction. T-cells are not an exception. One of their roles is to properly detect and eliminate cancer cells. These processes occur at the expense of ATP. Therefore, it can be concluded that a decrease in c-ATP can defect T-cell function and promote cancer evolution. In this article, we provide a hypothesis to describe the correlation between the expression of PD-1 protein on T-cells and their c-ATP levels. Moreover, we present the possible predictive factors of Anti–PD(L)-1 therapy which has not yet been determined definitely.
Subject: Medicine And Pharmacology, Clinical Medicine Keywords: creatine; statin; myopathy; muscle; myalgia; prevention; treatment; pathogenesis; pathophysiology; mitochondria
Online: 11 September 2019 (04:43:37 CEST)
Statins prevent cardiovascular diseases, yet their use is limited by the muscle disturbances they cause. Rarely, statin-induced myopathy is autoimmune, but more commonly it is due to direct muscle toxicity. Available evidence suggests that statin-induced creatine deficiency may be a major cause of this toxicity, and that creatine supplementation prevents it. Statins inhibit guanidinoacetate methyl transferase (GAMT), the last enzyme in the synthesis of creatine, thus they decrease its intracellular content. Such decreased content could cause mitochondrial impairment, since creatine is the final acceptor of the phosphate group of adenosine triphosphate (ATP) at the end of mitochondrial oxidative phosphorylation. Decreased cellular synthesis of adenosine triphosphate (ATP) would follow. Accordingly, ATP synthesis is decreased in statin-treated cells. In vitro, creatine supplementation prevents the opening of mitochondrial permeability transition pore caused by statins. Clinically, creatine administration prevents statin myopathy in statin-intolerant patients. Additional research is warranted to hopefully confirm these findings. However, creatine is widely used by athletes with no adverse events, and has demonstrated to be safe even in double-blind, placebo-controlled trials of elder individuals. Thus, it should be trialed, under medical supervision, in patients who cannot assume statin due to the occurrence of muscular symptoms.
REVIEW | doi:10.20944/preprints201908.0038.v1
Subject: Medicine And Pharmacology, Oncology And Oncogenics Keywords: solid cancers; cell cycle; apoptosis; inflammation; mitochondria; stemness; tumor suppression
Online: 5 August 2019 (03:43:33 CEST)
The Signal Transducer and Activator of Transcription (STAT)3 and 5 are activated by many cytokine receptors to regulate specific gene expression and mitochondrial functions. Their role in cancer is largely context dependent as they can both act as oncogenes and tumor suppressors. We review here the role of STAT3/5 activation in solid cancers and summarize their association to survival in cancer patients. The molecular mechanisms that underpins the oncogenic activity of STAT3/5 signaling includes the regulation of genes that control cell cycle, cell death, inflammation and stemness. In addition, STAT3 mitochondrial functions are required for transformation. On the other hand, several tumor suppressor pathways act on or are activated by STAT3/5 signaling including the p19ARF/p53 pathway, tyrosine phosphatases, suppressor of cytokine signaling 1 and 3, the sumo ligase PIAS3, the E3 ubiquitin ligase TMF/ARA160 and the miRNAs miR-124 and miR-1181. Cancer mutations and epigenetic alterations may alter the balance between pro-oncogenic and tumor suppressor activities associated to STAT3/5 signaling explaining their context dependent association to tumor progression both in human cancers and animal models.
ARTICLE | doi:10.20944/preprints202301.0500.v1
Subject: Biology And Life Sciences, Biochemistry And Molecular Biology Keywords: Alzheimer’s Disease (AD) mitochondria; endoplasmic reticulum (ER); serial block-face scanning electron microscopy (SBFSEM); three-dimensional electron microscopy (3D EM); small molecule mitochondria targeted therapeutics
Online: 27 January 2023 (10:08:59 CET)
Alzheimer’s Disease (AD) has no cure. Earlier, we showed that partial inhibition of mitochondrial complex I (MCI) with small molecule CP2 induces adaptive stress response activating multiple neuroprotective mechanisms. Chronic treatment reduced inflammation, improved synaptic and mitochondrial functions, and blocked neurodegeneration in symptomatic APP/PS1 mice, a translational model of AD. Here, using serial block-face scanning electron microscopy (SBFSEM) and three-dimensional (3D) EM reconstructions combined with Western blot analysis and next-generation RNA sequencing, we demonstrate that CP2 treatment also restores mitochondrial morphology and mitochondria-endoplasmic reticulum (ER) communication in the APP/PS1 mouse brain. Using 3D EM volume reconstructions, we show that mitochondria in AD dendrites exist primarily as mitochondria-on-a-string (MOAS). Compared to other morphological phenotypes, MOAS are extensively enveloped in the ER membranes forming multiple mitochondria-ER contact sites (MERCS) known to contribute to abnormal lipid and calcium homeostasis. CP2 treatment specifically reduced MOAS formation, consistent with improved energy homeostasis in the brain, with concomitant reduction in MERCS, ER stress, and improved lipid homeostasis. These data provide novel information on the role MOAS play in AD and additional support for further development of partial MCI inhibitors as disease modifying strategy for AD.
ARTICLE | doi:10.20944/preprints202311.1783.v1
Subject: Biology And Life Sciences, Biochemistry And Molecular Biology Keywords: telomere length; mitochondria; oxidation; body mass index; IVF/ICSI; male infertility
Online: 28 November 2023 (07:56:30 CET)
Abstract: Important variables that affect the quality and functionality of sperm and may affect male reproductive health and fertility include telomere length, mitochondrial content, and the ratio of mitochondrial DNA (mtDNA) to nuclear DNA (nDNA). The purpose of this study was to look at the connections between these three sperm characteristics and how they might affect a woman's ability to conceive. Methods: Data were collected from 82 men who underwent IVF/ICSI at the University Hospital of Ioannina's IVF Unit in the Obstetrics and Gynecology Department. Evaluations included sperm morphology, sperm count, sperm motility, and participant history. To address this, males of reproductive age who were categorized into three body mass index (ΒΜΙ) groups—normal, overweight, and obese—had their sperm samples tested. Results: Our findings indicate a negative correlation between relative telomere length and ΒΜΙ for both the normal and overweight groups. Conversely, a positive correlation was observed for the obese group, indicating a possible relationship between mitochondrial health and telomere maintenance. The results were statistically significant only for the obese group. Furthermore, a negative correlation was observed between telomere length and mitochondrial content in both the normal and overweight groups, indicating that a lower mitochondrial content may be linked to longer telomeres. Nonetheless, there was a positive correlation for the group that was obese. For all three groups, the data did not reach statistical significance. Given that mitochondrial con-centration and telomere length are both markers of cellular integrity and health, these correla-tions may have an impact on the quality of sperm. Furthermore, the relative telomere length of the normal and overweight groups had a negative correlation with the ratio of mtDNA to nDNA, though the obese group showed a positive correlation. The findings were not statistical-ly significant in any of the groups under investigation. According to this, male fertility may be negatively impacted by an imbalance in the copy number of the mitochondrial genome com-pared to the nuclear DNA in sperm. Conclusions: Our research, in essence, emphasizes the interaction among human sperm telo-mere length, mitochondrial concentration, and the mtDNA to nDNA ratio. Gaining knowledge of these correlations could help explain the reasons behind male infertility and open up new treatment options for reproductive health problems. The functional importance of these correla-tions and possible uses in therapeutic contexts require more investigation.
ARTICLE | doi:10.20944/preprints202310.1628.v1
Subject: Biology And Life Sciences, Biochemistry And Molecular Biology Keywords: acute myeloid leukemia; mass spectrometry; proteomic; phosphoproteomic; relapse; mitochondria; FAB subtypes
Online: 25 October 2023 (10:07:27 CEST)
AML is a highly aggressive and heterogeneous form of hematological cancer. Proteomics-based stratification of patients into more refined subgroups may contribute to a more precise characterization of the patient-derived AML cells. Here, we reanalyzed liquid chromatography-tandem mass spectrometry (LC-MS/MS) generated proteomic and phosphoproteomic data from 26 chemoresistant/relapse (RELAPSE) and 15 relapse-free (REL_FREE) AML patients. We considered not only the RELAPSE and REL_FREE characteristics but also integrated the French-American-British (FAB) classification, along with considering the presence of nucleophosmin 1 (NPM1) mutation and cytogenetically normal AML. We found a significant number of differentially enriched proteins (911) and phosphoproteins (257) between the various FAB subtypes in RELAPSE patients. Patients with the myeloblastic M1/M2 subtype showed higher levels of RNA processing-related routes and lower levels of signaling related to terms like translation and degranulation, when compared to the M4/M5 subtype. Moreover, we found that high abundance of proteins associated to mitochondrial translation and oxidative phosphorylation, particularly observed in the RELAPSE M4/M5 NPM1 mutated subgroup, distinguishes relapsing from non-relapsing AML patient cells with the FAB subtype M4/M5. Thus, the discovery of subtype-specific biomarkers through proteomic profiling may complement the existing classification system for AML and potentially aid in selecting personalized treatment strategies for individual patients.
REVIEW | doi:10.20944/preprints202310.0962.v1
Subject: Medicine And Pharmacology, Medicine And Pharmacology Keywords: oxygen; nanobubbles; hypoxia; mitochondria; metabolism, molecular; drug delivery; cancer, stress; innovation
Online: 16 October 2023 (11:09:22 CEST)
Worldwide, hypoxia-related conditions, including cancer, COVID-19, and neuro-degenerative diseases, often lead to multi-organ failure and significant mortality. Oxygen, crucial for cellular function, becomes scarce as levels drop below 10 mmHg (<2% O2), triggering mitochondrial dysregulation and activating hypoxia-induced factors (HiFs). Herein, Oxygen nanoBubbles (OnB), an emerging versatile oxygen de-livery platform, implies to offer a novel approach to address hypoxia-related pathologies. This review explores OnB oxygen delivery strategies and systems, including diffusion, ultrasound, photodynamic, and pH-responsive nanobubbles. It delves into the nanoscale mechanisms of OnB, elucidating their role in mitochondrial metabolism (TFAM, PGC1alpha), hypoxic responses (HiF-1alpha), and their interplay in chronic pathologies including cancer and neurodegenerative disorders, amongst others. By understanding these dynamics and underlying mechanisms, this article aims to contribute to our accruing knowledge of OnB and the developing potential in ameliorating hypoxia- and metabolic stress-related conditions and fostering innovative therapies.
ARTICLE | doi:10.20944/preprints202307.1993.v1
Subject: Biology And Life Sciences, Biophysics Keywords: mitochondria; membrane; fusion; Mifofusin; amphipathic helix; divalent cations; lipid packing defects
Online: 28 July 2023 (11:29:25 CEST)
Mitochondria are highly dynamic organelles that constantly undergo fusion and fission events to maintain their shape, distribution, and cellular function. Mitofusin 1 and 2 proteins are two dynamin-like GTPases involved in the fusion of outer mitochondrial membranes (OMM). Mitofusins are anchored to the OMM through their transmembrane domain and possess two heptad repeat domains (HR1 and HR2) in addition to their N-terminal GTPase domain. The HR1 domain was found to induce fusion via its amphipathic helix, which interacts with the lipid bilayer structure. The lipid composition of mitochondrial membranes can also impact mitochondrial fusion. However, the precise mode of action of lipids in mitochondrial fusion is not fully understood. In this study, we have examined the role of the mitochondrial lipids phosphatidylethanolamine (PE), cardiolipin (CL) and phosphatidic acid (PA) in membrane fusion induced by the HR1 domain, both in the presence and absence of divalent cations (Ca2+ or Mg2+). Our results show that PE, as well as PA in the presence of Ca2+, effectively stimulate HR1-mediated fusion, while CL has a slight inhibitory effect. By considering the biophysical properties of these lipids in the absence or presence of divalent cations, we infer that the interplay between divalent cations and specific cone-shaped lipids creates regions with packing defects in the membrane, which provides a favorable environment for the amphipathic helix of HR1 to bind to the membrane and initiate fusion.
REVIEW | doi:10.20944/preprints202306.1903.v1
Subject: Medicine And Pharmacology, Endocrinology And Metabolism Keywords: Fasting; autophagy; long-COVID; post-vaccination syndrome; spike protein; mitochondria; mitophagy
Online: 27 June 2023 (12:33:46 CEST)
Fasting, a practice with historical roots in various cultures, has recently garnered significant interest in the field of medicine. In this article, we delve into the mechanisms underlying fasting-induced autophagy and its therapeutic applications for spike protein associated pathology. We explore the therapeutic potential of fasting on spike protein-related pathology and the role of interventions to upregulate autophagy, including compounds like spermidine, resveratrol, rapamycin, and metformin. In conclusion, fasting, coupled with an understanding of its nuances, holds promise as a therapeutic intervention for spike protein related diseases; with broad implications for human health. This review presents the therapeutic possibility of using autophagy to treat spike protein related diseases, and details the interventions to deploy this therapeutic modality.
REVIEW | doi:10.20944/preprints202306.1306.v1
Subject: Medicine And Pharmacology, Endocrinology And Metabolism Keywords: Fasting; autophagy; long-COVID; post-vaccination syndrome; spike protein; mitochondria; mitophagy
Online: 19 June 2023 (07:39:57 CEST)
Fasting, a practice with historical roots in various cultures, has recently garnered significant interest in the field of medicine. In this article, we delve into the mechanisms underlying fasting-induced autophagy and its therapeutic applications for spike protein associated pathology. We explore the therapeutic potential of fasting on spike protein-related pathology. Additionally, we discuss factors that affect fasting, such as duration, type (dry vs. water), and the role of specific compounds like spermidine, resveratrol, rapamycin, and metformin. Furthermore, we analyse the interactions between fasting and other practices such as exercise, and highlight important considerations regarding participant characteristics, including pregnancy, breastfeeding, medication interactions, and metabolic disorders. In conclusion, fasting, coupled with an understanding of its nuances, holds promise as a therapeutic intervention with broad implications for human health.
ARTICLE | doi:10.20944/preprints202302.0287.v1
Subject: Biology And Life Sciences, Biochemistry And Molecular Biology Keywords: HAX1; Che-1/AATF; apoptosis; mitochondria; oxidative stress; breast cancer; ERα
Online: 17 February 2023 (01:50:45 CET)
HAX1 is a multifunctional protein involved in the antagonism of apoptosis in cellular response to oxidative stress. In the present study we identified HAX1 as novel binding partner for Che-1/AATF, a pro-survival factor which plays a crucial role in fundamental processes, including response to multiple stresses and apoptosis. HAX1 and Che-1 proteins show extensive colocalization in mitochondria and we demonstrated that their association is strengthened after oxidative stress stimuli. Interestingly, in MCF-7 cells, resembling luminal estrogen receptor (ER) positive breast cancer, we found that Che-1 depletion correlates with decreased HAX1 mRNA and protein levels, and this event is not significantly affected by oxidative stress induction. Furthermore, we observed an enhancement of the previously reported interaction between HAX1 and estrogen receptor alpha (ERα) upon H2O2 treatment. These results indicate the two anti-apoptotic proteins HAX1 and Che-1 as coordinated players in cellular response to oxidative stress with a potential role in estrogen sensitive breast cancer cells.
REVIEW | doi:10.20944/preprints202301.0538.v2
Subject: Medicine And Pharmacology, Obstetrics And Gynaecology Keywords: placenta; mitochondria; preeclampsia; disease subclasses; pregnancy; hypertension; reactive oxygen species; therapies
Online: 10 February 2023 (04:09:05 CET)
The placenta is a vital organ of pregnancy, regulating adaptation to pregnancy, gestational-parent/fetal exchange and ultimately fetal development and growth. Not surprisingly, in cases of placental dysfunction - where aspects of placental development or function become compromised - adverse pregnancy outcomes can result. One common placenta-mediated disorder of pregnancy is preeclampsia (PE), a hypertensive disorder of pregnancy with a highly heterogeneous clinical presentation. The wide array of clinical characteristics observed in pregnant individuals and neonates of a PE pregnancy are likely the result of distinct forms of placental pathology underlying the PE diagnosis, explaining why no one common intervention has proven effective in the prevention or treatment of PE. The historical paradigm of placental pathology in PE highlights an important role for utero-placental malperfusion, placental hypoxia and oxidative stress, and a critical role for placental mitochondrial dysfunction in the pathogenesis and progression of the disease. In the current review, the evidence of placental mitochondrial dysfunction in the context of PE will be summarized, highlighting how altered mitochondrial function may be a common feature across distinct PE subtypes. Further, advances in this field of study and therapeutic targeting of mitochondria as a promising intervention for PE will be discussed.
REVIEW | doi:10.20944/preprints202206.0421.v1
Subject: Biology And Life Sciences, Biology And Biotechnology Keywords: Mitochondria; Respiratory chain; Krebs cycle; Succinate; Cancer; Encephalopathy; SDH, SDHI; pesticides
Online: 30 June 2022 (08:31:22 CEST)
Research focused on succinate dehydrogenase (SDH) and its substrate, succinate, culminated in the 50’s accompanying the rapid development of research dedicated to bioenergetics and intermediary metabolism. This allowed to uncover the implication of the SDH in both the mitochondrial respiratory chain and the Krebs cycle. Nowadays this theme is experiencing a real revival following the discovery of the role of SDH and succinate in a subset of tumors and cancers in human. The aim of this review is to enlighten the many questions yet unanswered, ranging from fundamental to clinically oriented aspects, up to the danger of the current use of SDH as a target for a sub class of pesticides.
REVIEW | doi:10.20944/preprints202109.0109.v1
Subject: Biology And Life Sciences, Biochemistry And Molecular Biology Keywords: proteomics; transcriptomics; DNA methylation; mitochondria; metabolism; OXPHOS; ASD; neurogenesis; gliosis; neurodevelopment
Online: 6 September 2021 (17:14:37 CEST)
Abstract: Autism Spectrum Disorder (ASD) is a complex neurodevelopmental disorder with extensive genetic and aetiological heterogeneity. While the underlying molecular mechanisms involved remain unclear, significant progress has been facilitated by recent advances in high-throughput transcriptomic, epigenomic and proteomic technologies. Here, we review recently published ASD proteomic data and compare proteomic func-tional enrichment signatures to those of transcriptomic and epigenomic data. We iden-tify canonical pathways that are consistently implicated in ASD molecular data and find an enrichment of pathways involved in mitochondrial metabolism and neurogenesis. We identify a subset of differentially expressed proteins that are supported by ASD tran-scriptomic and DNA methylation data. Furthermore, these differentially expressed proteins are enriched for disease phenotype pathways associated with ASD aetiology. These proteins converge on protein-protein interaction networks that regulate cell pro-liferation and differentiation, metabolism and inflammation which demonstrates a link between canonical pathways, biological processes and the ASD phenotype. This review highlights how proteomics can uncover potential molecular mechanisms to explain a link between mitochondrial dysfunction and neurodevelopmental pathology.
REVIEW | doi:10.20944/preprints202011.0227.v1
Subject: Medicine And Pharmacology, Immunology And Allergy Keywords: Organelle transport; Charcot-Marie-Tooth; Axonal transport deficiency; Neurodegeneration; Cytoskeleton; Mitochondria
Online: 6 November 2020 (08:55:15 CET)
Charcot-Marie-Tooth (CMT) disease is the most commonly inherited neurological disorder, defined by progressive deterioration of the peripheral nerves. Clinical manifestations of CMT mutations are typically limited to peripheral neurons, the longest cells in the body. Currently, mutations in at least 80 different genes are associated with CMT and new mutations are regularly being discovered. A large portion of the proteins mutated in axonal CMT have documented roles in mitochondrial mobility. This suggests that trafficking defects may be a common underlying mechanism in CMT. This review will focus on the potential role of altered mitochondrial mobility in the pathogenesis of axonal CMT, highlighting the challenges and opportunities to this “impaired mobility” model of the disease.
Subject: Medicine And Pharmacology, Cardiac And Cardiovascular Systems Keywords: Diabetic Cardiomyopathy; Hyperglycemia; Ischemia/Reperfusion Injury; Metabolism; Mitochondria; Remote Conditioning; Exercise
Online: 17 March 2020 (08:52:25 CET)
Metabolic syndrome, diabetes and ischemic heart disease are among the leading causes of death and disability in Western countries. Diabetic cardiomyopathy is responsible for the most severe signs and symptoms. An important strategy for reducing the incidence of cardiovascular disease is regular exercise. Remote ischemic conditioning has some similarity with exercise, and can be induced by short periods of ischemia and reperfusion of a limb, and it can be performed in people who cannot exercise. There is abundant evidence that exercise is beneficial in diabetes and ischemic heart disease, but there is a need to elucidate the specific cardiovascular effects of emerging and unconventional forms of exercise in people with diabetes. Also, remote ischemic conditioning may be considered among the options to induce beneficial effects in these patients. The characteristics and interactions of diabetes and ischemic heart disease, and the known effects of exercise and remote ischemic conditioning in the presence of metabolic syndrome and diabetes, are analyzed in this brief review.
ARTICLE | doi:10.20944/preprints201909.0043.v3
Subject: Biology And Life Sciences, Immunology And Microbiology Keywords: Myalgic Encephalomyelitis; Chronic Fatigue Syndrome; mitochondria; Complex V; TORC1; Seahorse respirometry
Online: 3 February 2020 (09:34:29 CET)
Myalgic Encephalomyelitis/Chronic Fatigue Syndrome (ME/CFS) is an enigmatic condition characterized by exacerbation of symptoms after exertion (post-exertional malaise or “PEM”), and by fatigue whose severity and associated requirement for rest are excessive and disproportionate to the fatigue-inducing activity. There is no definitive molecular marker or known underlying pathological mechanism for the condition. Increasing evidence for aberrant energy metabolism suggests a role for mitochondrial dysfunction in ME/CFS. Our objective was therefore to measure mitochondrial function and cellular stress sensing in actively metabolising patient blood cells. We immortalized lymphoblasts isolated from 51 ME/CFS patients diagnosed according to the Canadian Consensus Criteria and an age- and gender-matched control group. Parameters of mitochondrial function and energy stress sensing were assessed by Seahorse extracellular flux analysis, proteomics, and an array of additional biochemical assays. As a proportion of the basal oxygen consumption rate (OCR), the rate of ATP synthesis by Complex V was significantly reduced in ME/CFS lymphoblasts, while significant elevations were observed in Complex I OCR, maximum OCR, spare respiratory capacity, nonmitochondrial OCR and “proton leak” as a proportion of the basal OCR. This was accompanied by a reduction of mitochondrial membrane potential, chronically hyperactivated TOR Complex I stress signalling and upregulated expression of mitochondrial respiratory complexes, fatty acid transporters and enzymes of the β-oxidation and TCA cycles. By contrast, mitochondrial mass and genome copy number, as well as glycolytic rates and steady state ATP levels were unchanged. Our results suggest a model in which ME/CFS lymphoblasts have a Complex V defect accompanied by compensatory upregulation of their respiratory capacity that includes the mitochondrial respiratory complexes, membrane transporters and enzymes involved in fatty acid β-oxidation. This homeostatically returns ATP synthesis and steady state levels to “normal” in the resting cells, but may leave them unable to adequately respond to acute increases in energy demand as the relevant homeostatic pathways are already activated.
ARTICLE | doi:10.20944/preprints201905.0094.v1
Subject: Physical Sciences, Thermodynamics Keywords: time; availability; irreversibility; time dilation; biological clock; metabolic efficiency; telomere; mitochondria
Online: 8 May 2019 (11:21:50 CEST)
In Newtonian mechanics, time as well as space are perceived as absolute entities. In 2 Einstein’s special relativity, time is frame dependent. Time is also affected by gravitational field 3 and as the field varies in space, time also varies throughout space. In the present article, a 4 thermodynamic-based time is investigated. The entity is called "irreversibility", which is generated 5 when availability (also known as exergy) is destroyed. Since each thermodynamic system may 6 generate different amount of irreversibility, this quantity is system dependent. The time’s arrow is 7 automatically satisfied, since irreversibility generation always proceeds in one direction (toward 8 future). We have demonstrated that, like common time, irreversibility is frame dependent, and 9 affected by gravity in the similar manner as the common time. For this reason, we propose to 10 assign the entity irreversibility of the system as thermodynamic time. A possible application of the 11 thermodynamic time is an interpretation and managing of the aging of biological systems. The 12 metabolic efficiency is related to the irreversibility of the chemical processes and affect the aging of 13 the system. Our sensation of time-flow may be attributed to the flow of availability and destruction 14 of it through the living system. It is shown by other authors that entropy generation (equivalent to 15 irreversibility) is a parameter for the human life span. Since the thermodynamic time is based on a 16 concept of thermodynamics that is universal, further applications to other subjects, such as biological 17 clock, telomere, and cosmology are possible.