Lower Mitochondrial Membrane Potential Research Articles

Cell–cell heterogeneity in phosphoenolpyruvate carboxylase biases early cell fate priming in Dictyostelium discoideum

Glucose metabolism is a key factor characterizing the cellular state during multicellular development. In metazoans, the metabolic state of undifferentiated cells correlates with growth/differentiation transition and cell fate determination. Notably, the cell fate of the Amoebozoa species Dictyostelium discoideum is biased by the presence of glucose and is also correlated with early differences in intracellular ATP. However, the relationship between early cell–cell heterogeneity, cell differentiation, and the metabolic state is unclear. To address the link between glucose metabolism and cell differentiation in D. discoideum, we studied the role of phosphoenolpyruvate carboxylase (PEPC), a key enzyme in the PEP-oxaloacetate-pyruvate node, a core junction that dictates the metabolic flux of glycolysis, the TCA cycle, and gluconeogenesis. We demonstrate that there is cell–cell heterogeneity in PEPC promoter activity in vegetative cells, which depends on nutrient conditions, and that cells with high PEPC promoter activity differentiate into spores. The PEPC null mutant exhibited an aberrantly high prestalk/prespore ratio, and the spore mass of the fruiting body was glassy and consisted of immature spores. Furthermore, the PEPC null mutant had high ATP levels and low mitochondrial membrane potential. Our results suggest the importance of cell–cell heterogeneity in the levels of metabolic enzymes during early cell fate priming.

Dnajc5b contributes to male fertility by maintaining the mitochondrial functions and autophagic homeostasis during spermiogenesis

DnaJ heat shock protein family member C5 beta (DNAJC5B), also known as cysteine-string protein beta, exhibits a prominent expression in testicular tissue and plays an important role in acrosomal exocytosis in vitro. Nevertheless, the precise role and underlying mechanism of DNAJC5B in spermatogenesis and male fertility remain poorly understood. The meta-analysis of RNA-sequencing datasets from porcine and murine testes reveals that Dnajc5b could be a pivotal factor in spermatogenesis. This study illustrates that male fertility declines with an increased ratio of abnormal spermatozoa in germ-cell knockout Dnajc5b mice. DNAJC5B has been identified as a mitochondrial protein with high expression in spermatids. The absence of DNAJC5B induces a cascade of mitochondrial damages, including oxidative stress, mitochondrial stress in the testes, and lower mitochondrial membrane potential of spermatozoa. In vivo and in vitro evidence demonstrates that DNAJC5B mitigates excessive cellular autophagy and mitophagy via DNAJ domain under environmental stress conditions, such as starvation or exposure to mitochondrial uncouplers FCCP and CCCP. This study highlights the important role of DNAJC5B in safeguarding male fertility by preserving mitochondrial function and regulating autophagy during spermiogenesis.

Adipose-derived stem cells regulate mitochondrial dynamics to alleviate the aging of HFF-1 cells.

The objective of this study is to explore how adipose-derived stem cells (ASCs) regulate mitochondrial structure and function and the impact of this regulation on slowing cellular senescence. HFF-1 cells were induced by H2O2 to establish a cellular senescence model, and ASCs or Mdivi-1 (mitochondrial fission inhibitor) was added. MTT examined the cell proliferation; flow cytometry detected mitochondrial membrane potential as well as apoptosis and cell cycle; kit measured ATP production; ELISA analyzed the levels of interleukin-6 (IL-6), interleukin 1 beta (IL-1β), tumor necrosis factor alpha-like (TNF-α), glutathione (GSH), malondialdehyde (MDA), and superoxide dismutase (SOD); Western blotting and qRT-PCR detected the expression of protein and mRNA levels; and β-galactosidase staining observed the degree of cellular senescence. Compared to normal HFF-1 cells, senescent HFF-1 cells exhibited weaker proliferative capacity, marked apoptosis, and G0-G1 cell cycle arrest. These cells also showed lower mitochondrial membrane potential and ATP production, higher expression of inflammatory factors, oxidative damage, and increased levels of senescence. Treatment with Mdivi-1 or ASCs enhanced HFF-1 cell proliferation, reduced apoptosis and cell cycle arrest, increased mitochondrial membrane potential and ATP production, decreased the expression of inflammatory factors, and mitigated oxidative stress, thereby reducing the degree of cellular senescence. Concurrent intervention with Mdivi-1 and ASCs further diminishes the impacts of cellular senescence. In conclusion, ASCs regulate mitochondrial dynamics (promoting mitochondrial fusion and inhibiting mitochondrial fission), enhance ATP production, and upregulate mitochondrial membrane potential, thereby alleviating cell cycle arrest, apoptosis, inflammatory responses, and oxidative stress induced by senescence in HFF-1 cells.

Buyang Huanwu Decoction reduces mitochondrial autophagy in rheumatoid arthritis synovial fibroblasts in hypoxic culture by inhibiting the BNIP3-PI3K/Akt pathway.

To investigate the role of the BNIP3-PI3K/Akt signaling pathway in mediating the inhibitory effect of Buyang Huanwu Decoction (BYHWT) on mitochondrial autophagy in human synovial fibroblasts from rheumatoid arthritis patients (FLS-RA) cultured under a hypoxic condition. Forty normal Wistar rats were randomized into two groups (n=20) for daily gavage of BYHWT or distilled water for 7 days to prepare BYHWT-medicated or control sera. FLS-RA were cultured in routine condition or exposed to hypoxia (10% O2) for 24 h wigh subsequent treatment with IL-1β, followed by treatment with diluted BYHWT-medicated serum (5%, 10% and 20%) or control serum. AnnexinV-APC/7-AAD double staining and T-AOC kit were used for detecting apoptosis and total antioxidant capacity of the cells, and the changes in ROS, ATP level, mitochondrial membrane potential and Ca2+ homeostasis were analyzed. The changes in mRNA and protein expressions of BNIP3, PI3K and AKT and mRNA expressions of LC3, Beclin-1 and P62 were detected using RT-qPCR and Western blotting. Treatment with BYHWT-medicated serum dose-dependently lowered apoptosis rate of IL-1β-induced FLS-RA with hypoxic exposure. The treatment significantly decreased T-AOC concentration, increased ROS production, autophagosome formation and ATPase levels, and lowered mitochondrial membrane potential and Ca2+ level in the cells. In IL-1β-induced FLS-RA with hypoxic exposure, treatment with BYHWT-medicated serum significantly increased BNIP3 protein expression, decreased the protein expressions of PI3K and AKT, increased the mRNA expressions of BNIP3 and P62, and lowered the mRNA expressions of PI3K, AKT, LC3 and Beclin-1 without significantly affecting Beclin-1 protein expression. The cells treated with 5% and 10% BYHWT-medicated serum showed no significant changes in LC3 expression. BYHWT inhibits mitochondrial autophagy in IL-1β-induced FLS-RA with hypoxic exposure possibly by inhibiting BNIP3-mediated PI3K/AKT signaling pathway.

Ezetimibe Enhances Lipid Droplet and Mitochondria Contact Formation, Improving Fatty Acid Transfer and Reducing Lipotoxicity in Alport Syndrome Podocytes.

Mitochondrial dysfunction is a critical factor in the pathogenesis of Alport syndrome (AS), contributing to podocyte injury and disease progression. Ezetimibe, a lipid-lowering drug, is known to inhibit cholesterol and fatty acid uptake and to reduce triglyceride content in the kidney cortex of mice with AS. However, its effects on lipid droplet (LD) utilization by mitochondria have not been explored. Transmission electron microscopy (TEM) and mitochondrial functional assays (ATP production, mitochondrial membrane potential, and citrate synthase activity) were used to investigate the impact of ezetimibe on LD-mitochondria contact formation and mitochondrial function in Col4a3KO (AS) and wildtype (WT) podocytes. TEM analysis revealed significant mitochondrial abnormalities in AS podocytes, including swollen mitochondria and reduced cristae density, while mitochondrial function assays showed decreased ATP production and lowered mitochondrial membrane potential. AS podocytes also demonstrated a higher content of LD but with reduced LD-mitochondria contact sites. Ezetimibe treatment significantly increased the number of LD-mitochondria contact sites, enhanced fatty acid transfer efficiency, and reduced intracellular lipid accumulation. These changes were associated with a marked reduction in the markers of lipotoxicity, such as apoptosis and oxidative stress. Mitochondrial function was significantly improved, evidenced by increased basal respiration, ATP production, maximal respiration capacity, and the restoration of mitochondrial membrane potential. Additionally, mitochondrial swelling was significantly reduced in ezetimibe-treated AS podocytes. Our findings reveal a novel role for ezetimibe in enhancing LD-mitochondria contact formation, leading to more efficient fatty acid transfer, reduced lipotoxicity, and improved mitochondrial function in AS podocytes. These results suggest that ezetimibe could be a promising therapeutic agent for treating mitochondrial dysfunction and lipid metabolism abnormalities in AS.

MYBPC3 D389V Variant Induces Hypercontractility in Cardiac Organoids.

MYBPC3, encoding cardiac myosin binding protein-C (cMyBP-C), is the most mutated gene known to cause hypertrophic cardiomyopathy (HCM). However, since little is known about the underlying etiology, additional in vitro studies are crucial to defining the underlying molecular mechanisms. Accordingly, this study aimed to investigate the molecular mechanisms underlying the pathogenesis of HCM associated with a polymorphic variant (D389V) in MYBPC3 by using isogenic human-induced pluripotent stem cell (hiPSC)-derived cardiac organoids (hCOs). The hiPSC-derived cardiomyocytes (hiPSC-CMs) and hCOs were generated from human subjects to define the molecular, cellular, functional, and energetic changes caused by the MYBPC3D389V variant, which is associated with increased fractional shortening and highly prevalent in South Asian descendants. Recombinant C0-C2, N' region of cMyBP-C (wild-type and D389V), and myosin S2 proteins were also utilized to perform binding and motility assays in vitro. Confocal and electron microscopic analyses of hCOs generated from noncarriers (NC) and carriers of the MYBPC3D389V variant revealed the presence of highly organized sarcomeres. Furthermore, functional experiments showed hypercontractility, faster calcium cycling, and faster contractile kinetics in hCOs expressing MYBPC3D389V than NC hCOs. Interestingly, significantly increased cMyBP-C phosphorylation in MYBPC3D389V hCOs was observed, but without changes in total protein levels, in addition to higher oxidative stress and lower mitochondrial membrane potential (ΔΨm). Next, spatial mapping revealed the presence of endothelial cells, fibroblasts, macrophages, immune cells, and cardiomyocytes in the hCOs. The hypercontractile function was significantly improved after the treatment of the myosin inhibitor mavacamten (CAMZYOS®) in MYBPC3D389V hCOs. Lastly, various vitro binding assays revealed a significant loss of affinity in the presence of MYBPC3D389V with myosin S2 region as a likely mechanism for hypercontraction. Conceptually, we showed the feasibility of assessing the functional and molecular mechanisms of HCM using highly translatable hCOs through pragmatic experiments that led to determining the MYBPC3D389V hypercontractile phenotype, which was rescued by the administration of a myosin inhibitor.

Status of sperm mitochondrial functions and DNA methylation in infertile men with clinical varicocele before and after treatment

Varicocele has been associated with reduced male fertility potential. Treatment modalities for varicocele improve semen parameters, yet more than 50% of cases remain infertile. Varicocele-induced heat and hypoxia stress may affect sperm mitochondrial functions, possibly leading to aberrant epigenetic modifications. This study includes 30 fertile men and 40 infertile men with clinical varicocele. The effect of varicocele treatment (antioxidant supplementation and or varicocelectomy) was evaluated after 3 months of treatment. Mitochondrial membrane potential (MMP) and intracellular reactive oxygen species (iROS) were measured by flow cytometry using JC-1 and DCFDA, respectively. mtDNA copy number and deletions were determined by PCR. DNA methylation was analysed by pyrosequencing. Present investigations suggest that infertile men with varicocele have abnormal semen parameters; significantly low MMP, high iROS, and high mtDNA copy number. Semen parameters were improved in a subset of men of both the treatment modalities; however, it was noted that varicocelectomy helped better in improving sperm parameters compared to antioxidant treatment. Both treatment modalities helped in reducing iROS and mtDNA copy number significantly; however, they were noneffective in improving MMP. Altered DNA methylation at mitochondria D loop and mitochondrial structure and function genes UQCRC2, MIC60, TOM22, and LETM1 (promoter region) were observed in varicocele group. The DNA methylation levels were restored after varicocele treatment; however, the restoration was not consistent at all CpG sites. Both the treatment modalities helped in restoring the altered DNA methylation levels of mitochondrial genes but the restoration is nonhomogeneous across the studied CpG sites.

Di-(2-ethylhexyl) Phthalate Exposure Induces Developmental Toxicity in the Mouse Fetal Heart via Mitochondrial Dysfunction.

Congenital heart disease (CHD) is a major cause of infant mortality and morbidity, with growing interest in the role of environmental factors in its etiology. Di-(2-ethylhexyl) phthalate (DEHP), an environmental endocrine disruptor, has been implicated in the development of CHD. This study aimed to investigate the effects of DEHP exposure on fetal heart development in mice. Pregnant mice exposed to DEHP exhibited increased fetal malformations, decreased fetal weight, and reduced crown-rump length.f Transcriptomic analysis revealed the downregulation of genes involved in aerobic respiration and mitochondrial ATP synthesis. Functional assays demonstrated reduced mitochondrial respiration, decreased ATP production, elevated reactive oxygen species levels, and lowered mitochondrial membrane potential in DEHP-exposed fetal cardiomyocytes. These findings underscore the detrimental effects of DEHP on fetal cardiac health and provide insights into the molecular mechanisms underlying DEHP-induced CHD. Understanding these mechanisms is crucial for developing preventive strategies against environmental toxicants that affect fetal cardiac development.

Energy Metabolic Profile in Oral Potentially Malignant Disorders and Oral Squamous Cell Carcinoma: A Preliminary Landscape of Warburg Effect in Oral Cancer.

We hypothesized that cell energy metabolic profiles correlate with normal, dysplastic, and tumor cell/tissue statuses and may be indicators of aggressiveness in oral squamous cell carcinoma (OSCC) cells. The energy-related proteins that were differentially expressed in human OSCC fragments (n = 3) and their adjacent epithelial tissue (TAE) were verified using mass spectrometry (MS). Immunohistochemistry for 4-hydroxynonenal (4-HNE) was performed to evaluate the oxidative stress patterns in OSCC (n = 10), epithelial dysplasia (n = 9), and normal epithelial (n = 4) biopsies. The metabolic energy profile of OSCC aggressiveness was investigated in human OSCC cell lines with different levels of epithelial-mesenchymal transition proteins. The genes associated with the proteins found by MS in this study were analyzed using survival analysis (OS), whereas the genes associated with a poorer prognosis were analyzed using context-specific expression, Gene Ontology (GO) and Cancer Hallmarks for function enrichment analysis. The rationale for all experimental approach was to investigate whether the variation in energy metabolism profile accompanies the different phenotypes (from epithelial to mesenchymal) during the epithelial-mesenchymal transition. All OSCC fragments exhibited an increase in glycolysis-related proteins and a decrease in mitochondrial activity compared to the TAE region (p < 0.05), probably due to the downregulation of pyruvate dehydrogenase and antioxidant proteins. Additionally, the OSCC cell lines with a mesenchymal profile (SCC4, SCC9, and SCC25) had a lower mitochondrial mass and membrane potential and generated lower levels of reactive oxygen and nitrogen species than the TAE region. When we analyzed 4-HNE, the reactive species levels were increased in the epithelial regions of OSCC and potentially malignant lesions. A decrease in the levels of 4-HNE/reactive species was observed in the connective tissue underlying the dysplastic regions and the OSCC invasion zone. Based on this scenario, aggressive OSCC is associated with high glycolytic and oxidative metabolism and low mitochondrial and antioxidant activities, which vary according to the differentiation level of the tumor cells and the stage of carcinogenesis.

Bleomycin in vitro exposure decreases markers of human male gamete competence

To investigate the in vitro impact of bleomycin on human sperm DNA integrity, functionality, and morphology, with the aim of elucidating the underlying mechanism and anticipating potential repercussions on patients' reproductive function. Controlled laboratory-based in vitro investigation. Surplus human ejaculate donated for research by 45 reproductive-age participants exhibiting normozoospermic sperm parameters following clinical semen analysis. None of the participants had received a cancer diagnosis or undergone radiotherapy, chemotherapy, or both. After clinical semen analysis, sperm samples were centrifuged, diluted in sperm preparation medium (SPM), and exposed to bleomycin (100 μg/mL) for two hours at 37ºC in a humidified incubator with 5% CO2. In vitro human sperm competence was evaluated by comparing raw sperm, sperm incubated with SPM, and sperm exposed to bleomycin. Competence indicators included sperm motility, vitality, DNA and acrosome integrity, and mitochondrial membrane potential. Transmisson electron microscopy was employed to correlate the ultrastructural morphological findings with functional assays. Exposure to bleomycin for two hours in vitro significantly (P < 0.001) decreased sperm vitality, motility, and chromatin condensation compared to raw and control sperm. It also significantly (P < 0.001) increased sperm DNA fragmentation and the proportion of sperm with low mitochondrial membrane potential. Additionally, bleomycin significantly (P < 0.05) retarded the acrosomal response compared to control but did not affect the formation of intracellular and extracellular reactive oxygen species. Bleomycin-induced ultrastructural morphological changes supported the detected functional alterations. Bleomycin negatively impacts male gamete competency in humans. Healthcare professionals should vigilantly monitor and further investigate the gonadotoxicity effects of bleomycin, in addition to its recognized lung toxicity. Meanwhile, it is recommended that cancer patients undergoing bleomycin-containing chemotherapy regimens receive guidance on fertility preservation strategies.

Mitochondria dysfunction is one of the causes of diclofenac toxicity in the green alga Chlamydomonas reinhardtii.

Non-steroidal anti-inflammatory drugs (NSAIDs), such as diclofenac (DCF), form a significant group of environmental contaminants. When the toxic effects of DCF on plants are analyzed, authors often focus on photosynthesis, while mitochondrial respiration is usually overlooked. Therefore, an in vivo investigation of plant mitochondria functioning under DCF treatment is needed. In the present work, we decided to use the green alga Chlamydomonas reinhardtii as a model organism. Synchronous cultures of Chlamydomonas reinhardtii strain CC-1690 were treated with DCF at a concentration of 135.5 mg × L-1, corresponding to the toxicological value EC50/24. To assess the effects of short-term exposure to DCF on mitochondrial activity, oxygen consumption rate, mitochondrial membrane potential (MMP) and mitochondrial reactive oxygen species (mtROS) production were analyzed. To inhibit cytochrome c oxidase or alternative oxidase activity, potassium cyanide (KCN) or salicylhydroxamic acid (SHAM) were used, respectively. Moreover, the cell's structure organization was analyzed using confocal microscopy and transmission electron microscopy. The results indicate that short-term exposure to DCF leads to an increase in oxygen consumption rate, accompanied by low MMP and reduced mtROS production by the cells in the treated populations as compared to control ones. These observations suggest an uncoupling of oxidative phosphorylation due to the disruption of mitochondrial membranes, which is consistent with the malformations in mitochondrial structures observed in electron micrographs, such as elongation, irregular forms, and degraded cristae, potentially indicating mitochondrial swelling or hyper-fission. The assumption about non-specific DCF action is further supported by comparing mitochondrial parameters in DCF-treated cells to the same parameters in cells treated with selective respiratory inhibitors: no similarities were found between the experimental variants. The results obtained in this work suggest that DCF strongly affects cells that experience mild metabolic or developmental disorders, not revealed under control conditions, while more vital cells are affected only slightly, as it was already indicated in literature. In the cells suffering from DCF treatment, the drug influence on mitochondria functioning in a non-specific way, destroying the structure of mitochondrial membranes. This primary effect probably led to the mitochondrial inner membrane permeability transition and the uncoupling of oxidative phosphorylation. It can be assumed that mitochondrial dysfunction is an important factor in DCF phytotoxicity. Because studies of the effects of NSAIDs on the functioning of plant mitochondria are relatively scarce, the present work is an important contribution to the elucidation of the mechanism of NSAID toxicity toward non-target plant organisms.

MitoQ relieves mitochondrial dysfunction in UVA and cigarette smoke-induced Fuchs endothelial corneal dystrophy

Fuchs endothelial corneal dystrophy (FECD), a degenerative corneal condition, is characterized by the droplet-like accumulation of the extracellular matrix, known as guttae and progressive loss of corneal endothelial cells ultimately leading to visual distortion and glare. FECD can be influenced by environmental stressors and genetic conditions. However, the role of mitochondrial dysfunction for advancing FECD pathogenesis is not yet fully studied. Therefore, in the present study we sought to determine whether a combination of environmental stressors (ultraviolet-A (UVA) light and cigarette smoke condensate (CSC)) can induce mitochondrial dysfunction leading to FECD. We also investigated if MitoQ, a water-soluble antioxidant, can target mitochondrial dysfunction induced by UVA and CSC in human corneal endothelial cells mitigating FECD pathogenesis. We modeled the FECD by increasing exogenous oxidative stress with CSC (0.2%), UVA (25J/cm2) and a combination of UVA + CSC and performed a temporal analysis of their cellular and mitochondrial effects on HCEnC-21T immortalized cells in vitro before and after MitoQ (0.05 μM) treatment. Interestingly, we observed that a combination of UVA + CSC exposure increased mitochondrial ROS and fragmentation leading to a lower mitochondrial membrane potential and increased levels of cytochrome c release leading to apoptosis and cell death. MitoQ intervention successfully mitigated these effects and restored cell viability. The UVA + CSC model could be used to study stress induced mitochondrial dysfunction. Additionally, MitoQ can serve as a viable antioxidant in attenuating mitochondrial dysfunction, underscoring its potential as a molecular-focused treatment approach to combat FECD pathogenesis.

Nano-enabled thermo-responsive local delivery of tamoxifen and carvacrol for enhanced anticancer action

Tamoxifen (TMX) is widely employed in the treatment of breast cancer. However, owing to its poor solubility (BCS class II drug), rapid first-pass metabolism and free radical generation leading to hepatotoxicity, a better drug delivery platform is required. A sufficient concentration of TMX must be achieved while avoiding harm to healthy cells in the target for effective therapy. Carvacrol (CV), a natural monoterpene, has reported antitumor activity and cell growth inhibition effects on MCF-7 and MDA-MB-231 breast cancer cells. In the current study, TMX and CVR-loaded nano-emulsion was prepared and incorporated into thermosensitive poloxamer gel to achieve enhanced anticancer action locally. Box-Behnken Design was employed to extensively optimize the prepared formulation wherein the droplet size obtained was 97.53 ± 1.80 nm and PDI was 0.195 ± 0.0026. The developed thermogel was characterized for gelation temperature, rheology, hemolysis and drug release. The gelation and higher viscosity were attended closer to body temperature (37 ± 0.5 °C), and showed retarded drug release (∼60 % after 5 days). The developed thermogel showed 16.02 % hemolysis as compared to 71.89 % from free TMX. Further, In-vitro cell culture studies of the developed formulation revealed significantly enhanced cytotoxicity and almost 6-fold higher cellular internalization. In addition, dose-dependent lowering of mitochondrial membrane potential and 5.9-fold higher ROS production by TMX-CVR-NE was observed. Therefore, an in-situ thermo-gel depot of TMX and CVR imparted an attractive way for the controlled delivery and enhanced local activity of TMX in breast cancer.

Transplanting mitochondria from gastric epithelial cells reduces the malignancy of gastric cancer

Mitochondria are essential for energy supplementation and metabolic homeostasis of cancer cells. Using mitochondria transplantation to reduce the malignancy of gastric cancer (GC) cells is herein proposed. In our study normal human gastric mucous epithelium cell line (GES-1) showed a lower mitochondrial membrane potential (MMP) compared to immortalized human vascular endothelial cell line (EAhy 926) and human gastric adenocarcinoma cell line (AGS). The transplantation of GES-1 mitochondria to AGS were confirmed both by confocal microscopy and flow cytometry. After transplanting GES-1 mitochondria, the AGS showed a reduced cell migration, and invasion without affecting cell viability and apoptosis. Investigating the expression of proteins involved in epithelial-mesenchymal-transition (EMT), transplanted GES-1 mitochondria reduced the expression of mesenchymal markers α-SMA, MMP-9, snail, vimentin and N-cadherin, whereas the epithelial markers E-cadherin and clauding-1 were not changed. The proteins implicated in the cell cycle such as cyclin B1 and D1 were decreased. In mice, inoculation with AGS carrying the transplanted GES-1 mitochondria resulted in smaller sized tumors. Further investigating the mitochondrial balance, the transplanted GES-1 mitochondria were more stably preserved compared to endogenous AGS mitochondria. The MMP, ATP production and mitochondrial mass decreased in GES-1 mitochondria and the mitophagic proteins LC3 II and PINK1 were up-regulated. In conclusion the decreased malignancy of AGS was a result of exogenous GES-1 mitochondria transplantation. This suggests for a therapy with low efficiency mitochondria transplantation in the treatment of cancer cells.

P-357 Exposure to bleomycin in vitro reduces biomarkers of human male gamete competence

Abstract Study question Does male human sperm exposure to bleomycin in vitro affect their aptitude to breed? Summary answer Bleomycin, an antitumor antibiotic, adversely impacts human male gamete morphology and functionality, thus potentially compromising male fertility. What is known already Bleomycin is a chemotherapeutic agent used to treat a number of tumors that affect males of reproductive age. Hitherto, its effect on human male reproductive capacity alone has not been previously shown. The little information available on this subject relates to in vivo animal studies and supports the feasibility of this study. Study design, size, duration Between November 2022 and June 2023, individuals of reproductive age were enrolled in this study and had their clinical semen analyzed. The remaining ejaculate was supplied by 45 participants with sperm concentration above the World Health Organization (WHO) threshold for scientific purposes. Sperm were isolated from seminal plasma in the ejaculate of each individual, diluted to a concentration of 16 X 106 sz/mL (raw). Participants/materials, setting, methods In vitro incubation was performed in sperm preparation medium (SPM; control) or bleomycin (100 µg/mL; exposed) augmented for two hours at 37oC and 5% CO2. The results of exposed group were compared to raw and control. To evaluate the competence of human sperm, markers such as acrosome and DNA integrity, mitochondrial membrane potential, sperm motility, vitality, and oxidative stress were evaluated. Ultrastructural data from transmission electron microscopy was also obtained and correlated with functional experiments. Main results and the role of chance The participants were all of reproductive age (median age of 36 years old). The raw sperm parameters fulfilled the normozoospermia threshold set by the WHO, 2021. Prior to the current trial, none of the participants had been diagnosed with cancer or had received chemotherapy, radiation therapy, or both. Bleomycin exposure for two hours in vitro significantly (P &amp;lt; 0.001) reduced sperm motility, vitality, and chromatin condensation as compared to raw and control sperm. Moreover, bleomycin significantly (P &amp;lt; 0.001) increased the percentage of sperm with DNA fragmentation (sDNAfrag) and low mitochondrial membrane potential (MMP). Broad strands were significantly (P &amp;lt; 0.001) attained by bleomycin-induced breaks in the sperm DNA (Head staining pattern), which were succeeded by histone-rich areas (PAR-post-acrossomic region staining pattern). Additionally, bleomycin significantly (P &amp;lt; 0.05) delayed the acrossomic response, but had no significantly influence on the generation of extracellular and intracellular reactive oxygen species or in its reconstitution. Modifications in ultrastructural morphology caused by bleomycin corroborate the results obtained by functional tests. Limitations, reasons for caution Bleomycin impact on male fertility competence in vivo remains crucial. Increased sample sizes, including prepubertal subjects, are needed to pinpoint the precise bleomycin’s mechanism to cause oxidative stress, apoptosis, and sDNAfrag. Long-term implications on fertility and reproductive health, besides methods to lessen or offset bleomycin’s effects, should also be pursued. Wider implications of the findings Bleomycin adversely affects male gamete competence in humans. Along with its accompanying lung toxicity, healthcare practitioners should actively monitor and further investigate bleomycin’s gonadotoxicity in males. It is advised that all cancer patients undergoing chemotherapy treatments that contain bleomycin be provided with a fertility preservation plan in the meantime. Trial registration number not applicable

L-Palmitoylcarnitine supplementation improves oocyte quality and embryo development derived from obese mice

Changes in fatty acid composition caused by diet or exposure to diets that promote obesity can impact the quality of eggs and embryos, as well as the health of the resulting offspring. Palmitoylcarnitine, as an important intermediate for fatty acid transport across the inner mitochondrial membrane, undergoes a substantial increase during oocyte maturation. However, its impact on oocyte/embryo development remains unknown. In the present study, by establishing a high-fat diet (HFD)-induced model of obesity, we systematically evaluated the effects of palmitoylcarnitine supplementation on oocyte competence and embryo quality derived from obese mice. We found that palmitoylcarnitine supplement during in vitro culture markedly ameliorates the meiotic defects and genomic instability in HFD oocytes. The abnormal mitochondrial distribution and the lowered mitochondrial membrane potential in HFD oocytes are also prevented simultaneously, indicative of the improved mitochondrial function. Moreover, palmitoylcarnitine administration is capable of suppressing blastocyst apoptosis and promoting early embryo development from HFD mice. Taken together, our results suggest that palmitoylcarnitine has beneficial effects on oocyte quality exposed to maternal obesity via modulating meiotic structure and energy metabolism.

Altered counts and mitochondrial mass of peripheral blood leucocytes in patients with chronic hepatitis B virus infection.

Hepatitis B virus (HBV) damages liver cells through abnormal immune responses. Mitochondrial metabolism is necessary for effector functions of white blood cells (WBCs). The aim was to investigate the altered counts and mitochondrial mass (MM) of WBCs by two novel indicators of mitochondrial mass, MM and percentage of low mitochondrial membrane potential, MMPlow%, due to chronic HBV infection. The counts of lymphocytes, neutrophils and monocytes in the HBV infection group were in decline, especially for lymphocyte (p = 0.034) and monocyte counts (p = 0.003). The degraded MM (p = 0.003) and MMPlow% (p = 0.002) of lymphocytes and MM (p = 0.005) of monocytes suggested mitochondrial dysfunction of WBCs. HBV DNA within WBCs showed an extensive effect on mitochondria metabolic potential of lymphocytes, neutrophils and monocytes indicated by MM; hepatitis B e antigen was associated with instant mitochondrial energy supply indicated by MMPlow% of neutrophils; hepatitis B surface antigen, antiviral therapy by nucleos(t)ide analogues and prolonged infection were also vital factors contributing to WBC alterations. Moreover, degraded neutrophils and monocytes could be used to monitor immune responses reflecting chronic liver fibrosis and inflammatory damage. In conclusion, MM combined with cell counts of WBCs could profoundly reflect WBC alterations for monitoring chronic HBV infection. Moreover, HBV DNA within WBCs may be a vital factor in injuring mitochondria metabolic potential.

MYBPC3 D389V Variant Induces Hypercontractility in Cardiac Organoids.

MYBPC3 , encoding cardiac myosin binding protein-C (cMyBP-C), is the most mutated gene known to cause hypertrophic cardiomyopathy (HCM). However, since little is known about the underlying etiology, additional in vitro studies are crucial to defining the underlying molecular mechanisms. Accordingly, this study aimed to investigate the molecular mechanisms underlying the pathogenesis of HCM associated with a polymorphic variant (D389V) in MYBPC3 by using human-induced pluripotent stem cell (hiPSC)-derived cardiac organoids (hCOs). The hiPSC-derived cardiomyocytes (hiPSC-CMs) and hCOs were generated from human subjects to define the molecular, cellular, and functional changes caused by the MYBPC3 D389V variant. This variant is associated with increased fractional shortening and is highly prevalent in South Asian descendants. Recombinant C0-C2, N'-region of cMyBP-C (wildtype and D389V), and myosin S2 proteins were also utilized to perform binding and motility assays in vitro . Confocal and electron microscopic analyses of hCOs generated from noncarriers (NC) and carriers of the MYBPC3 D389V variant revealed the presence of highly organized sarcomeres. Furthermore, functional experiments showed hypercontractility with increased contraction velocity, faster calcium cycling, and faster contractile kinetics in hCOs expressing MYBPC3 D389V than NC hCOs. Interestingly, significantly increased cMyBP-C phosphorylation in MYBPC3 D389V hCOs was observed, but without changes in total protein levels, in addition to higher oxidative stress and lower mitochondrial membrane potential (ΔΨm). Next, spatial mapping revealed the presence of endothelial cells, fibroblasts, macrophages, immune cells, and cardiomyocytes in the hCOs. The hypercontractile function was significantly improved after treatment with the myosin inhibitor mavacamten (CAMZYOS®) in MYBPC3 D389V hCOs. Lastly, various in vitro binding assays revealed a significant loss of affinity in the presence of MYBPC3 D389V with myosin S2 region as a likely mechanism for hypercontraction. Conceptually, we showed the feasibility of assessing the functional and molecular mechanisms of HCM using highly translatable hCOs through pragmatic experiments that led to determining the MYBPC3 D389V hypercontractile phenotype, which was rescued by administration of a myosin inhibitor. Novelty and Significance: What Is Known?: MYBPC3 mutations have been implicated in hypertrophic cardiomyopathy. D389V is a polymorphic variant of MYBPC3 predicted to be present in 53000 US South Asians owing to the founder effect. D389V carriers have shown evidence of hyperdynamic heart, and human-induced pluripotent stem cells (hiPSC)-derived cardiomyocytes with D389V show cellular hypertrophy and irregular calcium transients. The molecular mechanism by which the D389V variant develops pathological cardiac dysfunction remains to be conclusively determined.What New Information Does This Article Contribute ?: The authors leveraged a highly translational cardiac organoid model to explore the role of altered cardiac calcium handling and cardiac contractility as a common pathway leading to pathophysiological phenotypes in patients with early HCM. The MYBPC3 D389V -mediated pathological pathway is first studied here by comparing functional properties using three-dimensional cardiac organoids differentiated from hiPSC and determining the presence of hypercontraction. Our data demonstrate that faster sarcomere kinetics resulting from lower binding affinity between D389V-mutated cMyBP-C protein and myosin S2, as evidenced by in vitro studies, could cause hypercontractility which was rescued by administration of mavacamten (CAMZYOS®), a myosin inhibitor. In addition, hypercontractility causes secondary mitochondrial defects such as higher oxidative stress and lower mitochondrial membrane potential (ΔΨm), highlighting a possible early adaptive response to primary sarcomeric changes. Early treatment of MYBPC3 D389V carriers with mavacamten may prevent or reduce early HCM-related pathology. GRAPHICAL ABSTRACT: A graphical abstract is available for this article.

Galectin-3-ITGB1 Signaling Mediates Interleukin 10 Production of Hepatic Conventional Natural Killer Cells in Hepatitis B Virus Transgenic Mice and Correlates with Hepatocellular Carcinoma Progression in Patients.

The outcomes of HBV infections are related to complex immune imbalances; however, the precise mechanisms by which HBV induces immune dysfunction are not well understood. HBV transgenic (HBs-Tg) mice were used to investigate intrahepatic NK cells in two distinct subsets: conventional NK (cNK) and liver-resident NK (LrNK) cells during a chronic HBV infection. The cNK cells, but not the LrNK cells, were primarily responsible for the increase in the number of bulk NK cells in the livers of ageing HBs-Tg mice. The hepatic cNK cells showed a stronger ability to produce IL-10, coupled with a higher expression of CD69, TIGIT and PD-L1, and lower NKG2D expression in ageing HBs-Tg mice. A lower mitochondrial mass and membrane potential, and less polarized localization were observed in the hepatic cNK cells compared with the splenic cNK cells in the HBs-Tg mice. The enhanced galectin-3 (Gal-3) secreted from HBsAg+ hepatocytes accounted for the IL-10 production of hepatic cNK cells via ITGB1 signaling. For humans, LGALS3 and ITGB1 expression is positively correlated with IL-10 expression, and negatively correlated with the poor clinical progression of HCC. Gal-3-ITGB1 signaling shapes hepatic cNK cells but not LrNK cells during a chronic HBV infection, which may correlate with HCC progression.

The effect of adipose-derived mesenchymal stem cell transplantation on ovarian mitochondrial dysfunction in letrozole-induced polycystic ovary syndrome in rats: the role of PI3K-AKT signaling pathway

ObjectiveThe present study aimed to elucidate how mesenchymal stem cells (MSCs) application could efficiently attenuate pathological changes of letrozole-induced poly cystic ovary syndrome (PCOS) by modulating mitochondrial dynamic via PI3K-AKT pathway.MethodsThirty-two female rats were randomly divided into four experimental groups: Sham, PCOS, PCOS + MSCs, and PCOS + MSCs + LY294002. The Sham group received 0.5% w/v carboxymethyl cellulose (CMC); the PCOS group received letrozole (1 mg/kg, daily) in 0.5% CMC for 21 days. Animals in the PCOS + MSCs group received 1 × 106 MSCs/rat (i.p,) on the 22th day of the study. In the PCOS + MSCs + LY294002 group, rats received LY294002 (PI3K-AKT inhibitor) 40 min before MSC transplantation. Mitochondrial dynamic gene expression, mitochondrial membrane potential (MMP), citrate synthase (CS) activity, oxidative stress, inflammation, ovarian histological parameters, serum hormone levels, homeostatic model assessment for insulin resistance (HOMA-IR), insulin and glucose concentrations, p-PI3K and p-AKT protein levels were evaluated at the end of the experiment.ResultsPCOS rats showed a significant disruption of mitochondrial dynamics and histological changes, lower MMP, CS, ovary super oxide dismutase (SOD) and estrogen level. They also had a notable rise in insulin and glucose concentrations, HOMA-IR, testosterone level, tumor necrosis factor-α (TNF-α) and interleukin-6 (IL-6) levels, ovarian malondialdehyde (MDA) content as well as a notable decrease in p-PI3K and p-AKT protein levels compared to the Sham group. In the PCOS + MSCs group, the transplantation of MSCs could improve the above parameters. Administration of LY294002 (PI3K-AKT pathway inhibitor) deteriorated mitochondrial dynamic markers, oxidative stress status, inflammation markers, hormonal levels, glucose, and insulin levels and follicular development compared to the PCOS + MSCs group.ConclusionsThis study demonstrated that the protective effects of MSC transplantation in regulating mitochondrial dynamics, promoting mitochondrial biogenesis, competing with redox status and inflammation response were mainly mediated through the PI3K-AKT pathway in the PCOS model.