bims-miptne Biomed News
on Mitochondrial permeability transition pore-dependent necrosis
Issue of 2026–05–03
fifteen papers selected by
Oluwatobi Samuel Adegbite, University of Liverpool



  1. bioRxiv. 2026 Apr 16. pii: 2026.04.13.718264. [Epub ahead of print]
      Mitochondrial calcium signaling integrates energy needs with energy production, amplifying or suppressing mitochondrial respiration in response to activity demand. Neuronal activity is tightly ATPcoupled to increases in mitochondrial calcium uptake, which stimulate the tricarboxylic acid cycle (TCA) and activate calcium-dependent enzymes important for ATP production via oxidative phosphorylation. The mitochondrial calcium uniporter (MCU) is the predominant source of matrix calcium and is differentially expressed across neuronal cell types, suggesting cell-type-specific differences in the coupling of activity-driven calcium levels and mitochondrial respiration. Here, we investigated whether elevating MCU expression enhances mitochondrial calcium uptake and oxidative phosphorylation in the hippocampus. We report that hippocampal mitochondria overexpressing MCU take up calcium at a faster rate without increased sensitivity to calcium overload. By modeling in vivo supply and demand, we found that hippocampal mitochondria overexpressing MCU are more efficient than control mitochondria at responding to increased bioenergetic demand. These findings reveal a role for MCU in modulating mitochondrial calcium uptake and boosting mitochondrial respiration under increasing demand, which contributes to our understanding of how specific cell types may adapt to different bioenergetic demands.
    DOI:  https://doi.org/10.64898/2026.04.13.718264
  2. Exp Mol Med. 2026 May 01.
      The mitochondrial calcium uniporter (Mcu) mediates calcium influx into the mitochondrial matrix, playing an essential role in cellular energy metabolism and survival. Although Mcu has been studied in various physiological contexts, its role in skeletal homeostasis remains poorly understood. Here we investigate how Mcu deficiency affects osteoblast differentiation and bone formation under aging-related stress. Using an inducible whole-body Mcu-knockout mouse model, we found that Mcu deletion resulted in impaired mitochondrial calcium uptake, reduced oxidative phosphorylation, fragmented mitochondrial morphology and decreased expression of osteogenic genes, leading to defective osteogenesis. Concurrently, adipogenic markers were elevated in Mcu-deficient bone marrow cells, indicating altered mesenchymal lineage commitment. Mechanistically, Mcu-deficient cells exhibited enhanced TGF-β signaling and reduced BMP/Wnt pathway activity. In vivo, inducible whole-body Mcu-knockout mice exhibited reduced trabecular bone volume and density while maintaining normal skeletal growth. Pharmacological modulation of mitochondrial calcium influx using kaempferol enhanced osteogenic differentiation and mitochondrial respiration in wild-type, but not Mcu-deficient, cells. Consistently, analysis of publicly available human datasets revealed age- and osteoporosis-associated downregulation of MCU expression in bone tissues. These findings suggest that Mcu regulates bone formation by controlling mitochondrial calcium uptake and mesenchymal lineage allocation. Targeting mitochondrial calcium signaling may offer novel therapeutic strategies for age-related skeletal disorders.
    DOI:  https://doi.org/10.1038/s12276-026-01705-3
  3. JACC Basic Transl Sci. 2026 Apr 24. pii: S2452-302X(26)00062-8. [Epub ahead of print]11(5): 101544
      Increased oxygen levels at birth regulate myocyte bioenergetic and structural maturation controlled by mitochondrial cyclophilin D (CypD). We evaluated mechanisms of neonatal hypoxic cardiac dysfunction by exposing neonatal mice to 12% oxygen and studied cardiac bioenergetics, myocyte maturation, and function. Hypoxia decreased the activity/assembly of electron transport chain complex I, uncoupled oxidative phosphorylation, increased proliferation, decreased differentiation, increased ventricular mass, and decreased cardiac function. CypD inhibition rescued most hypoxia-mediated effects and increased cardiac function. In conclusion, neonatal hypoxia alters cardiac bioenergetics, myocyte maturation, and cardiac function through CypD-dependent pathways, providing potential therapeutic targets for neonatal cardiac dysfunction.
    Keywords:  NIM811; cardiac development; cardiomyocyte maturation; cyclosporin A; mitochondria
    DOI:  https://doi.org/10.1016/j.jacbts.2026.101544
  4. Cell Signal. 2026 Apr 24. pii: S0898-6568(26)00198-1. [Epub ahead of print] 112546
      Dysregulation of intracellular Ca2+ signaling is a critical determinant of cell fate, however the contribution of non-canonical Ca2+ reservoirs to cancer-selective apoptosis remains incompletely understood. In this study, realgar transforming solution (RTS), a microbially processed arsenical, was employed as a biologically informative perturbation to investigate how lysosomal pH dysregulation a Ca2+-associated mitochondrial apoptotic program in triple-negative breast cancer (TNBC) cells. RTS exhibited superior selectivity compared with inorganic arsenic trioxide (ATO) and paclitaxel, significantly reducing the viability of TNBC cells (MDA-MB-231, BT-549, and MDA-MB-468) while sparing non-malignant MCF-10 A cells.. RTS-induced cell death was characterized by a Ca2+-dependent mitochondrial program-marked by cytochrome c release and caspase-9 activation-operating independently of reactive oxygen species accumulation and p53 signaling. Mechanistically, RTS triggered sustained cytosolic and mitochondrial Ca2+ overload originating from lysosomal mobilization rather than extracellular influx or endoplasmic reticulum depletion. Time-course profiling identified lysosomal acidic intensification as an early event, preceding TRPML1-mediated Ca2+ efflux and subsequent lysosomal membrane permeabilization (LMP). Consistently, pharmacological neutralization of the acidic shift (BafA1) or TRPML1 inhibition (ML-SI1) significantly attenuated the cytosolic Ca2+ elevation observed at the measured intervals. Collectively, these in vitro findings establish a "lysosome-mitochondria" signaling axis in which early pH perturbation represents a potential vulnerability in TNBC. While the multicomponent nature of RTS requires further characterization, this study provides preliminary insights into targeting organelle-specific Ca2+ hubs as a complementary strategy for refractory solid tumors.
    Keywords:  Ca(2+) signaling; Intracellular Ca(2+) homeostasis; Lysosomal acidity perturbation; Mitochondrial apoptosis; Non-canonical signaling
    DOI:  https://doi.org/10.1016/j.cellsig.2026.112546
  5. Nucleic Acids Res. 2026 Apr 23. pii: gkag233. [Epub ahead of print]54(8):
      Mitochondrial DNA replication occurs at contact sites between the endoplasmic reticulum (ER) and mitochondria (ERMCS). Beyond the known role of the tubular ER protein RTN4, the factors regulating this process are poorly defined. Here, we show that repressing the ER protein ERLIN2 in human fibroblasts depletes ER-mitochondrial contact sites and inhibits mitochondrial DNA replication, as does silencing RTN4 or the ER-mitochondrial tether GRP75. GRP75 or RTN4 scarcity also decreases the level of the mitochondrial calcium uniporter (MCU), whose inhibition blocks mitochondrial DNA synthesis. Because ERMCS depletion did not diminish mitochondrial calcium, and MCU complex can transport manganese, we tested whether manganese could bypass these defects. Manganese supplementation restored mitochondrial DNA replication in cells lacking ERMCS or with inhibited MCU, identifying manganese as a critical mediator. We then considered mitochondrial transcription as a potential manganese target, since it provides both transcripts for gene expression and primers for DNA replication. In vitro, manganese inhibits transcription re-start and stimulates RNA synthesis at the light-strand origin of replication. These findings support a model in which ER-mitochondrial contact sites, in conjunction with MCU, deliver manganese from the ER to mitochondria to promote DNA replication, potentially by modulating mitochondrial RNA polymerase activity.
    DOI:  https://doi.org/10.1093/nar/gkag233
  6. Cell Commun Signal. 2026 May 01.
      Mitochondrial dysfunction resulting in mitochondrial DNA (mtDNA) leakage is one of the main triggers of immune responses in systemic lupus erythematosus (SLE). In contrast, mitochondrial RNA (mtRNA) leakage and its role in SLE remains poorly understood. Interferon-alpha (IFN-α) and immune complexes (ICs) are both pathogenic contributors to SLE. Following the detection of increased mtRNA in the serum of patients with SLE, we explored the mechanisms of mtRNA leakage. Exposure to IFN-α at 100 U/ml, a pathophysiological concentration detected in SLE patients with mild to moderate disease activity, resulted in mitochondrial permeability transition pore (mPTP) opening and voltage dependent anion channel 1 (VDAC1) oligomerization, leading to mtRNA leakage and downstream inflammatory pathway activation in bone marrow-derived macrophages (BMDMs) of mice. However, we did not observe the activation of BCL2 antagonist/killer 1 (BAK) and BAK/BCL2-associated X (BAX) (BAX/BAK) pores and mitophagy does not play roles in these effects. Overloaded mitochondrial calcium released from the endoplasmic reticulum is likely responsible for mitochondrial pore opening. Similar effects were observed with ICs treatment. Several commonly recognized events contributing to mitochondrial pore opening such as cell death, apoptosis and changes of mitochondrial membrane potential were not detected and a pan-caspase inhibitor Z-VAD-FMK could not block IFN-α and ICs-induced mtRNA release. Our studies demonstrated an unexpected phenomenon that a pathophysiological concentration of IFN-α and ICs can selectively induce mitochondrial pore opening leading to mtRNA release in primary macrophages.
    Keywords:  Interferon-alpha; Macrophages; Mitochondria; Mitochondrial RNA; Mitochondrial pore; Systemic lupus erythematosus
    DOI:  https://doi.org/10.1186/s12964-026-02910-3
  7. Methods Cell Biol. 2026 ;pii: S0091-679X(26)00095-6. [Epub ahead of print]206 23-42
      Apoptosis, a tightly regulated form of programmed cell death, eliminates damaged or malignant cells and is triggered by internal or external stress signals. A critical decision point is mitochondrial outer membrane permeabilization (MOMP), governed by BCL-2 family proteins. Pro-apoptotic members such as BAX and BAK form pores in the mitochondrial outer membrane, releasing intermembrane space proteins like cytochrome c into the cytoplasm. Once cytosolic, cytochrome c binds APAF-1 to form the apoptosome, which activates caspase-9 and subsequently caspase-3, driving apoptosis through cleavage of key cellular substrates. Cytochrome c release serves as a hallmark and point of no return in the apoptotic cascade. However, cytochrome c release can be variable, occurring at submaximal levels or from only a subset of mitochondria, which complicates detection in heterogeneous cell populations. To address this, we developed a semi-automated imaging-based method to quantify cytochrome c release at the single-cell level using immunofluorescence microscopy. Our approach uses CellProfiler, an open-source image analysis platform, to implement a pipeline that segments adherent cells into nuclear, mitochondrial, and cytoplasmic compartments based on compartment-specific reference stains. The pipeline quantifies cytochrome c distribution across these compartments, calculating the ratio of mitochondrially retained to cytoplasmic cytochrome c for each cell. Automation of segmentation and measurement ensures rapid, robust, and reproducible analysis, with only image acquisition and data interpretation performed manually. This method provides a quantitative readout of MOMP and can be readily adapted to any immunofluorescence-detectable protein given an appropriate compartmental marker, expanding its utility for broader cellular studies.
    Keywords:  Apoptosis; Cell segmentation; CellProfiler; Cytochrome c release; Immunofluorescene staining; MOMP; Semi-automated quantification
    DOI:  https://doi.org/10.1016/bs.mcb.2026.03.002
  8. Cells. 2026 Apr 17. pii: 713. [Epub ahead of print]15(8):
      Soleus muscle fibres display modest changes in tetanic force and [Ca2+]i during repeated contractions. In this study, we investigate whether increasing mitochondrial Ca2+ load during repeated contractions could induce premature fatigue. Intact, single fibres were dissected from the soleus muscles of adult mice. Mitochondrial Ca2+ was measured with rhod-2 in intact fibres. Fatigue was induced by 70 Hz, 350 ms tetani given at 2 s intervals in the absence and presence of 10 µM CGP-37157, a potent inhibitor of the mitochondrial Na+-Ca2+ exchanger. In soleus fibres fatigued in the absence of CGP-37157, tetanic force was significantly reduced by about 30% at the end of the fatiguing stimulation, while mitochondrial [Ca2+] increased to a maximum after about 50 tetani and returned to its resting level within 20 min after the end of the stimulation. In the presence of CGP-37157, the maximal mitochondrial [Ca2+] increase was more than twice that in control fibres. In addition, fatigue developed more rapidly and force remained depressed after the end of the stimulation. No difference in mitochondrial membrane potential or ROS production was seen between control and CGP-37157 conditions. We conclude that while modest increases in mitochondrial Ca2 may be beneficial, excessive mitochondrial Ca2 loading depresses muscle function.
    Keywords:  Ca2+; mitochondria; skeletal muscle
    DOI:  https://doi.org/10.3390/cells15080713
  9. Cell Death Dis. 2026 Apr 25.
      Mitochondrial cristae are intricately folded structures of the inner mitochondrial membrane that play essential roles in cellular energy production, metabolic regulation, and compartmentalization. Far from being passive folds, cristae are dynamic, functional entities central to mitochondrial bioenergetics. Their architecture maximizes membrane surface area and spatially organizes protein complexes to enhance oxidative phosphorylation and adenosine triphosphate (ATP) synthesis. The compartmentalized structure of cristae also establishes functional barriers that help maintain localized proton gradients, optimize metabolic reactions, and contribute to mitochondrial stability. These dual roles in energy transformation and spatial segregation underscore the importance of the cristae in supporting cellular homeostasis. The structural design and lipid composition of cristae with enrichment in cardiolipin also reflect their bacterial ancestry, revealing an evolutionary continuity from prokaryotic bioenergetic systems to eukaryotic organelles. Moreover, dynamic remodeling of cristae in response to stress, nutrient availability, and developmental cues highlights their adaptability in regulating mitochondrial performance and signaling pathways. Disruption of cristae architecture is increasingly implicated in neurodegenerative, cardiovascular, and metabolic diseases due to impaired ATP synthesis and compromised mitochondrial integrity. This review examines emerging insights into the organization, composition, and regulatory mechanisms of the cristae, emphasizing their role as both bioenergetic engines and protective compartments. Understanding the complex interplay between cristae structure and mitochondrial function may illuminate novel strategies for restoring mitochondrial health and targeting diseases linked to mitochondrial dysfunction. Cristae represent an evolutionary innovation that bridges structure and function, enabling the mitochondria to meet the multifaceted demands of the eukaryotic cell.
    DOI:  https://doi.org/10.1038/s41419-026-08779-x
  10. ACS Nano. 2026 Apr 30.
      Hepatic ischemia-reperfusion injury (IRI), driven primarily by excessive mitochondrial reactive oxygen species (ROS) generation, is a major cause of liver dysfunction, graft failure, and postoperative complications. However, no pharmacological agents have been clinically approved for its prevention or treatment, and there is an urgent need for effective therapeutic strategies. In this study, we established a nanoplatform composed of PEGylated polydopamine nanoparticles modified with the mitochondrial-targeting peptide SS-31 (PPS NPs). SS-31 peptide modification confers PPS NPs with efficient mitochondrial-targeting capability, thereby restoring mitochondrial membrane potential and reducing ROS accumulation in the hypoxia/reoxygenation model. Furthermore, treatment with PPS NPs significantly mitigates liver injury, decreases inflammatory factor levels, and inhibits neutrophil recruitment in mice subjected to IRI. Transcriptome sequencing and metabolomics analyses indicate that PPS NPs can protect the liver from ischemia-reperfusion injury by preserving mitochondrial integrity, reducing ROS generation, and regulating arachidonic acid and glutathione metabolism. By preserving mitochondrial function, maintaining cellular redox homeostasis, and suppressing inflammatory cascades, PPS NPs ultimately inhibit mitochondria-dependent apoptosis and confer protection against liver IRI, providing a practical therapeutic strategy for hepatic IRI clinical management.
    Keywords:  hepatic ischemia-reperfusion injury; mitochondria-targeted; oxidative stress; polydopamine nanoparticles; reactive oxygen species
    DOI:  https://doi.org/10.1021/acsnano.5c13406
  11. Mol Cell Biochem. 2026 Apr 27.
      Neurodegenerative diseases, including Alzheimer's disease, Parkinson's disease, Huntington's disease, amyotrophic lateral sclerosis, and multiple sclerosis, remain leading causes of disability and premature death. Although they present with distinct clinical phenotypes, they converge on several pathogenic processes. Among these, mitochondrial dysfunction has emerged as a key driver of neurodegeneration, encompassing impaired bioenergetic capacity, disturbed calcium handling, altered mitochondrial dynamics, insufficient mitophagy, and excessive production of reactive oxygen species (ROS). This review provides a focused synthesis of the ways in which mitochondrial pathology contributes to neurodegeneration across major neurodegenerative disorders and summarizes therapeutic strategies designed to target mitochondria. We outline disease-relevant mitochondrial abnormalities and connect them to neuronal loss, synaptic failure, and neuroinflammatory cascades, with particular attention to mitochondrial ROS and inflammatory signaling linked to mitochondrial DNA. The manuscript further evaluates current and emerging interventions, including mitochondria-targeted antioxidants, mitochondrial transfer/transplantation, exercise, dietary approaches, and nanotechnology-enabled delivery systems. For each strategy, we consider the mechanistic rationale, key preclinical findings, and barriers to translation. Across experimental models, many of these approaches confer measurable neuroprotection-often reflected by lower oxidative burden, stabilization of mitochondrial membrane potential, and partial restoration of ATP production. However, clinical findings have been inconsistent, suggesting that efficacy depends strongly on disease stage, patient heterogeneity, and the specific mitochondrial defect being targeted. By integrating mechanistic insights with therapeutic evidence, this review offers a structured perspective on shared and disease-specific features of mitochondrial dysfunction and highlights priorities for advancing mitochondria-centered interventions toward meaningful clinical benefit.
    Keywords:  Mitochondria; Mitochondrial dysfunction; Neurodegenerative diseases; Oxidative stress
    DOI:  https://doi.org/10.1007/s11010-026-05542-w
  12. Free Radic Biol Med. 2026 Apr 25. pii: S0891-5849(26)00451-X. [Epub ahead of print]
      Dysregulated calcium homeostasis and mitochondrial impairment are critical factors in the pathogenesis of sepsis-induced cardiomyopathy (SICM). STIM1 is crucial for maintaining calcium homeostasis. However, whether improving STIM1-mediated calcium handling can alleviate SICM remains unknown. This study aims to clarify the mechanism and the role of STIM1 in SICM. In this study, we first established a rat model of sepsis induced by LPS and clarified that the upregulation of STIM1 protein is associated with sepsis-induced cardiomyopathy (SICM). Myocardial-specific knockdown of STIM1 significantly improved cardiac function in septic rats. Moreover, using the calcium influx inhibitor BTP2, we elucidated that BTP2 could alleviate LPS-induced cardiomyopathy by improving calcium handling and mitochondrial function. Subsequently, we treated cardiomyocytes with LPS to explore the mechanism by which STIM1 promotes SICM. The results demonstrated that STIM1 amplifies store-operated calcium entry, triggering concomitant cytosolic and mitochondrial calcium overload. This induces Drp1-dependent mitochondrial fragmentation and dysfunction, resulting in elevated ROS production and subsequent activation of the NLRP3 inflammasome-mediated pyroptosis in cardiomyocytes, ultimately leading to LPS-induced cardiomyopathy. In conclusion, this study indicate that STIM1 promotes calcium overload, thereby facilitating mitochondrial dysfunction and ultimately resulting in pyroptosis. Targeting STIM1 may thus represent a promising therapeutic strategy for SICM.
    Keywords:  Mitochondria; Pyroptosis; SICM; STIM1; calcium
    DOI:  https://doi.org/10.1016/j.freeradbiomed.2026.04.150
  13. Proc Natl Acad Sci U S A. 2026 May 05. 123(18): e2528281123
      Mitochondria activate inflammation and innate immunity to protect against infections, but the role in cancer is unknown. Here, we report that patients with pancreatic ductal adenocarcinoma (PDAC) with reduced levels of the mitochondrial scaffold, Mic60, or inner mitochondrial membrane protein, exhibit increased inflammation, high NFκB activity and production of TNFα. This is mediated by double-stranded RNA (dsRNA) released from structurally defective, Mic60-low mitochondria, which engages TLR3/RIG-I sensing, activates NFκB gene expression and reprograms transcriptional and signaling networks to promote PDAC proliferation. Preclinical targeting of mitochondrial dsRNA signaling triggers rapid cell death and inhibition of tumor growth, selectively in Mic60-knockdown PDAC, without overt toxicity, in vivo. Therefore, dsRNA released from defective mitochondria generates protumorigenic inflammation and provides an actionable therapeutic target in selected PDAC patients.
    Keywords:  TLR3; dsRNA; inflammation; pancreatic cancer; viral mimicry
    DOI:  https://doi.org/10.1073/pnas.2528281123
  14. Methods Cell Biol. 2026 ;pii: S0091-679X(26)00085-3. [Epub ahead of print]206 55-80
      A myriad of diverse developmental and pro-death signals converge on the mitochondrial pathway of apoptosis, which is governed by the BCL‑2 family of proteins. Comprised of both pro- and anti-apoptotic family members, the BCL‑2 family functions to regulate mitochondrial outer membrane permeabilization (MOMP), often considered the "point of no return" in which a cell commits to an apoptotic outcome. Specifically, the effector BCL‑2 family proteins, BAX and BAK, are responsible for inducing MOMP and therefore investigations into their structural, cellular, and pharmacological regulation are critical to understanding the cellular commitment to apoptosis. A gold standard methodology for studying activation of BAX or BAK is the permeabilization of large unilamellar vesicles (LUVs), which are biochemically-defined model liposomes that mimic the major lipid composition of the outer mitochondrial membrane (OMM). Here, we provide a detailed protocol for generating LUVs containing a fluorescent dye/quencher pair to monitor real-time BAX activation and membrane permeabilization using a standard plate reader. Additionally, we detail example assay strategies to model interactions within the BCL‑2 family and provide a robust mathematical model for fitting and parameterizing kinetic LUV permeabilization data.
    Keywords:  Apoptosis; BAX; BCL‑2 family; Large unilamellar vesicles; MOMP; Regulated dell death
    DOI:  https://doi.org/10.1016/bs.mcb.2026.02.017
  15. Nat Struct Mol Biol. 2026 Apr 29.
      During apoptosis, the BCL-2 family members BAX and BAK oligomerize and form a pore to mediate the decisive step of mitochondrial outer membrane permeabilization. However, the contribution of additional cellular components to apoptotic pore dynamics remains poorly understood. Here we map the protein environment of the apoptotic pore using in situ proximity labeling and identify the mitochondrial carrier homolog protein MTCH2 localizing nearby BAX and BAK assemblies specifically under apoptotic conditions. We show that cells lacking MTCH2 exhibit delayed BAX and BAK oligomerization at the single-particle level, which can be rescued by addition of lysophosphatidic acid. Accordingly, MTCH2 depletion decreases not only apoptosis sensitivity but also sublethal mitochondrial permeabilization during bacterial infection, mitochondrial DNA release into the cytosol and cGAS-STING activation under impaired caspases. Our findings uncover a key role of MTCH2 in promoting BAX and BAK high-order assembly with functional consequences for apoptotic pore growth and downstream responses.
    DOI:  https://doi.org/10.1038/s41594-026-01805-8