Integrating Bioinformatics and Experimental Validation to Identify Mitochondrial Permeability Transition-Driven Necrosis-Related lncRNAs that can Serve as Prognostic Biomarkers and Therapeutic Targets in Endometrial Carcinoma.

Endometrial carcinoma (EC) is a common malignant tumor in women with high mortality and relapse rates. Mitochondrial permeability transition (MPT)-driven necrosis is a novel form of programmed cell death. The MPT-driven necrosis related lncRNAs (MRLs) involved in EC development remain unclear. We aimed to predict the outcomes of patients with EC by constructing a novel prognostic model based on MRLs and explore potential molecular functions. A risk prognostic model was developed utilizing multi-Cox regression in conjunction with the Least Absolute Shrinkage and Selection Operator (LASSO) regression algorithm, which was based on MRLs. The predictive efficacy of the model was evaluated through receiver operating characteristic (ROC) curve analysis, as well as nomogram and concordance index (C-index) assessments. Patients were categorized into high- and low-risk groups based on their median risk scores. Notably, the high-risk group exhibited significantly poorer overall survival (OS) outcomes. Gene ontology (GO) and Gene set enrichment analysis (GSEA) demonstrated that Hedgehog and cell cycle pathways were enriched in the high-risk group. Tumor Immune Dysfunction and Exclusion (TIDE) displayed that patients in the high-risk group showed a high likelihood of immune evasion and less effective immunotherapy. A significant disparity in immune function was also observed between two groups. Based on the nine-MRLs, drug sensitivity analysis identified several anticancer drugs with potential efficacy in prognosis. Meanwhile, the results demonstrated that OGFRP1 plays a carcinogenic role by affecting mitochondrial membrane permeability in EC. Therefore, the risk model constructed by nine MRLs could be used to predict the clinical outcomes and therapeutic responses in patients with EC effectively.

F-ATP synthase inhibitory factor 1 and mitochondria-organelle interactions: New insight and implications.

Mitochondria are metabolic hub, and act as primary sites for reactive oxygen species (ROS) and metabolites generation. Mitochondrial Ca2+ uptake contributes to Ca2+ storage. Mitochondria-organelle interactions are important for cellular metabolic adaptation, biosynthesis, redox balance, cell fate. Organelle communications are mediated by Ca2+/ROS signals, vesicle transport and membrane contact sites. The permeability transition pore (PTP) is an unselective channel that provides a release pathway for Ca2+/ROS, mtDNA and metabolites. F-ATP synthase inhibitory factor 1 (IF1) participates in regulation of PTP opening and is required for the translocation of transcriptional factors c-Myc/PGC1α to mitochondria to stimulate metabolic switch. IF1, a mitochondrial specific protein, has been suggested to regulate other organelles including nucleus, endoplasmic reticulum and lysosomes. IF1 may be able to mediate mitochondria-organelle interactions and cellular physiology through regulation of PTP activity.

Mitochondrial permeability transition mediated by MTCH2 and F-ATP synthase contributes to ferroptosis defense.

The opening of the mitochondrial permeability transition pore (PTP), a Ca2+-dependent pore located in the inner mitochondrial membrane, triggers mitochondrial outer membrane permeabilization (MOMP) and induces organelle rupture. However, the underlying mechanism of PTP-induced MOMP remains unclear. Mitochondrial carrier homolog 2 (MTCH2) mediates MOMP process by facilitating the recruitment of tBID to mitochondria. Here, we show that MTCH2 binds to cyclophilin D (CyPD) and promotes the dimerization of F-ATP synthase via interaction with subunit j. The interplay between MTCH2 and subunit j coordinates MOMP and PTP to mediate the occurrence of mitochondrial permeability transition. Knockdown of CyPD, MTCH2 and subunit j markedly sensitizes cells to RSL3-induced ferroptosis, which is prevented by MitoTEMPO, suggesting that mitochondrial permeability transition mediates ferroptosis defense.

Potential Targets for the Protective Effect of Astaxanthin on Ethanolinduced Damage in Rat Liver Mitochondria.

BACKGROUND: Alcohol intoxication leads to multiple degenerative disorders in the structure and function of mitochondria. The mechanisms underlying these disorders, as well as ways to prevent them, are an urgent task in biomedicine. We investigate the mechanism of the positive effect of AX on rat liver mitochondria after chronic alcohol administration and suggest the targets of its effects. In this work, we continued our studies of astaxanthin (AX) as a possible protector of mitochondria from the toxic effects of ethanol. METHOD: In our experiments, we used the Lieber-DeCarly model of chronic alcohol intoxication, which allows high-dose alcohol intake. Four groups of animals were used in the experiments: group 1 (control), group 2 (treated with AX), group 3 (treated with ethanol), and group 4 (treated with ethanol and AX together). Rat liver mitochondria (RLM) were isolated by the standard method modified in our laboratory. A multifunctional chamber with built-in electrodes was used to determine mitochondrial functions. Electrophoresis followed by Western blot analysis was used to detect mitochondrial proteins. Statistical significance was calculated using t-test Student-Newman- Keuls test. RESULT: AX has been shown to have a positive effect on the functioning of the mitochondrial permeability transition pore (mPTP), the regulation of signaling pathways, as well as mitochondrial dynamics. It was found that AX is able to suppress the degenerative effect of alcohol on liver mitochondria. Targets for the protective action of AX in rat liver mitochondria (RLM) have been proposed. CONCLUSION: The discovered protective effect of AX on liver mitochondria during alcohol damage may contribute to the development of new strategies for the treatment of alcohol- induced damage.

Cyclophilin D, regulator of the mitochondrial permeability transition, impacts bone development and fracture repair.

Mitochondrial Permeability Transition Pore (MPTP) and its key positive regulator, Cyclophilin D (CypD), control activity of cell oxidative metabolism important for differentiation of stem cells of various lineages including osteogenic lineage. Our previous work (Sautchuk et al., 2022) showed that CypD gene, Ppif, is transcriptionally repressed during osteogenic differentiation by regulatory Smad transcription factors in BMP canonical pathway, a major driver of osteoblast (OB) differentiation. Such a repression favors closure of the MPTP, priming OBs to higher usage of mitochondrial oxidative metabolism. The physiological role of CypD/MPTP regulation was demonstrated by its inverse correlation with BMP signaling in aging and bone fracture healing in addition to the negative effect of CypD gain-of-function (GOF) on bone maintenance. Here we show evidence that CypD GOF also negatively affects bone development and growth as well as fracture healing in adult mice. Developing craniofacial and long bones presented with delayed ossification and decreased growth rate, respectively, whereas in fracture, bony callus volume was diminished. Given that Genome Wide Association Studies showed that PPIF locus is associated with both body height and bone mineral density, our new data provide functional evidence for the role of PPIF gene product, CypD, and thus MPTP in bone growth and repair.

Interplay of mitochondrial calcium signalling and reactive oxygen species production in the brain.

Intracellular communication and regulation in brain cells is controlled by the ubiquitous Ca2+ and by redox signalling. Both of these independent signalling systems regulate most of the processes in cells including the cell surviving mechanism or cell death. In physiology Ca2+ can regulate and trigger reactive oxygen species (ROS) production by various enzymes and in mitochondria but ROS could also transmit redox signal to calcium levels via modification of calcium channels or phospholipase activity. Changes in calcium or redox signalling could lead to severe pathology resulting in excitotoxicity or oxidative stress. Interaction of the calcium and ROS is essential to trigger opening of mitochondrial permeability transition pore - the initial step of apoptosis, Ca2+ and ROS-induced oxidative stress involved in necrosis and ferroptosis. Here we review the role of redox signalling and Ca2+ in cytosol and mitochondria in the physiology of brain cells - neurons and astrocytes and how this integration can lead to pathology, including ischaemia injury and neurodegeneration.

Mechanism and treatment of intracerebral hemorrhage focus on mitochondrial permeability transition pore.

Intracerebral hemorrhage (ICH) is the second most common subtype of stroke, characterized by high mortality and a poor prognosis. Despite various treatment methods, there has been limited improvement in the prognosis of ICH over the past decades. Therefore, it is imperative to identify a feasible treatment strategy for ICH. Mitochondria are organelles present in most eukaryotic cells and serve as the primary sites for aerobic respiration and energy production. Under unfavorable cellular conditions, mitochondria can induce changes in permeability through the opening of the mitochondrial permeability transition pore (mPTP), ultimately leading to mitochondrial dysfunction and contributing to various diseases. Recent studies have demonstrated that mPTP plays a role in the pathological processes associated with several neurodegenerative diseases including Parkinson's disease, Alzheimer's disease, Huntington's disease, ischemic stroke and ischemia-reperfusion injury, among others. However, there is limited research on mPTP involvement specifically in ICH. Therefore, this study comprehensively examines the pathological processes associated with mPTP in terms of oxidative stress, apoptosis, necrosis, autophagy, ferroptosis, and other related mechanisms to elucidate the potential mechanism underlying mPTP involvement in ICH. This research aims to provide novel insights for the treatment of secondary injury after ICH.

Modulation of brain energy metabolism in hepatic encephalopathy: impact of glucose metabolic dysfunction.

Cerebral function is linked to a high level of metabolic activity and relies on glucose as its primary energy source. Glucose aids in the maintenance of physiological brain activities; as a result, a disruption in metabolism has a significant impact on brain function, launching a chain of events that leads to neuronal death. This metabolic insufficiency has been observed in a variety of brain diseases and neuroexcitotoxicity disorders, including hepatic encephalopathy. It is a significant neurological complication that develops in people with liver disease, ranging from asymptomatic abnormalities to coma. Hyperammonemia is the main neurotoxic villain in the development of hepatic encephalopathy and induces a wide range of complications in the brain. The neurotoxic effects of ammonia on brain function are thought to be mediated by impaired glucose metabolism. Accordingly, in this review, we provide an understanding of deranged brain energy metabolism, emphasizing the role of glucose metabolic dysfunction in the pathogenesis of hepatic encephalopathy. We also highlighted the differential metabolic profiles of brain cells and the status of metabolic cooperation between them. The major metabolic pathways that have been explored are glycolysis, glycogen metabolism, lactate metabolism, the pentose phosphate pathway, and the Krebs cycle. Furthermore, the lack of efficacy in current hepatic encephalopathy treatment methods highlights the need to investigate potential therapeutic targets for hepatic encephalopathy, with regulating deficient bioenergetics being a viable alternative in this case. This review also demonstrates the importance of the development of glucose metabolism-focused disease diagnostics and treatments, which are now being pursued for many ailments.

Pathological Role of High Sugar in Mitochondrial Respiratory Chain Defect-Augmented Mitochondrial Stress.

According to many research groups, high glucose induces the overproduction of superoxide anions, with reactive oxygen species (ROS) generally being considered the link between high glucose levels and the toxicity seen at cellular levels. Respiratory complex anomalies can lead to the production of ROS. Calcium [Ca2+] at physiological levels serves as a second messenger in many physiological functions. Accordingly, mitochondrial calcium [Ca2+]m overload leads to ROS production, which can be lethal to the mitochondria through various mechanisms. F1F0-ATPase (ATP synthase or complex V) is the enzyme responsible for catalyzing the final step of oxidative phosphorylation. This is achieved by F1F0-ATPase coupling the translocation of protons in the mitochondrial intermembrane space and shuttling them to the mitochondrial matrix for ATP synthesis to take place. Mitochondrial complex V T8993G mutation specifically blocks the translocation of protons across the intermembrane space, thereby blocking ATP synthesis and, in turn, leading to Neuropathy, Ataxia, and Retinitis Pigmentosa (NARP) syndrome. This study seeks to explore the possibility of [Ca2+]m overload mediating the pathological roles of high glucose in defective respiratory chain-mediated mitochondrial stress. NARP cybrids are the in vitro experimental models of cells with F1FO-ATPase defects, with these cells harboring 98% of mtDNA T8993G mutations. Their counterparts, 143B osteosarcoma cell lines, are the parental cell lines used for comparison. We observed that NARP cells mediated and enhanced the death of cells (apoptosis) when incubated with hydrogen peroxide (H2O2) and high glucose, as depicted using the MTT assay of cell viability. Furthermore, using fluorescence probe-coupled laser scanning confocal imaging microscopy, NARP cells were found to significantly enable mitochondrial reactive oxygen species (mROS) formation and enhance the depolarization of the mitochondrial membrane potential (ΔΨm). Elucidating the mechanisms of sugar-enhanced toxicity on the mitochondria may, in the future, help to alleviate the symptoms of patients with NARP syndromes and other neurodegenerative diseases.