bims-miptne Biomed News
on Mitochondrial permeability transition pore-dependent necrosis
Issue of 2026–02–15
eight papers selected by
Oluwatobi Samuel Adegbite, University of Liverpool



  1. Genes Dis. 2026 May;13(3): 101846
      Alzheimer's disease (AD) is a progressive neurodegenerative disorder characterized by cognitive decline and neuronal loss, with its pathogenesis tightly linked to a "pathological triad"-mitochondrial dysfunction, metabolic dysregulation, and calcium homeostasis imbalance. This triad forms a mutually reinforcing network that amplifies AD pathology, yet its precise causal relationships and clinical relevance remain incompletely understood. Here, we critically synthesize evidence from human studies, animal models, and in vitro systems to dissect how these dysfunctions interact in vivo: mitochondrial structural damage and bioenergetic failure (e.g., reduced cytochrome c oxidase activity) impair ATP production, triggering metabolic reprogramming (e.g., astrocytic Warburg-like glycolysis, lactate shuttle dysfunction) and disrupting calcium buffering via mitochondrial calcium uniporter (MCU) dysregulation. Conversely, metabolic stress (e.g., hyperglycemia-induced mitochondrial overload) and calcium overload (e.g., NMDA receptor hyperactivation) exacerbate mitochondrial damage through reactive oxygen species (ROS) bursts and mitochondrial permeability transition pore (mPTP) opening. These processes are further amplified by amyloid β-protein (Aβ) and tau pathology: Aβ oligomers directly inhibit mitochondrial respiration and activate calcium channels, while hyperphosphorylated tau disrupts mitochondrial trafficking and exacerbates metabolic enzyme dysfunction. We evaluate the clinical translatability of preclinical findings, highlighting inconsistencies (e.g., conflicting results of CoQ10 trials) and gaps (e.g., human-specific metabolic signatures). Finally, we propose a framework prioritizing multi-target therapies that disrupt the triad's vicious cycle, emphasizing the need for biomarkers to stratify patients based on triad dysregulation patterns.
    Keywords:  Alzheimer’s disease; Calcium homeostasis imbalance; Metabolic dysregulation; Mitochondrial dysfunction; Molecular mechanisms
    DOI:  https://doi.org/10.1016/j.gendis.2025.101846
  2. EMBO J. 2026 Feb 11.
      STIM1 is a transmembrane protein localized in the endoplasmic reticulum (ER), where it acts as a calcium ion sensor, activating store-operated Ca2+ entry upon ER Ca2+ depletion. Via cellular calcium influx, STIM1 is thought to indirectly affect mitochondrial calcium content. Here we show that STIM1 also interacts with mitochondrial proteins such as PTPIP51 and GRP75, suggesting its presence in mitochondria-associated ER membranes (MAMs), which are specialized ER regions that facilitate ER-mitochondria communication. Lowering STIM1 expression disrupts ER-to-mitochondria Ca2+ transfer, reduces basal mitochondrial Ca2+ levels, impairs maximal mitochondrial respiration, and reduces ATP production. The STIM1-GRP75 interaction depends on STIM1's Ca2+-sensing ability. ER Ca2+ depletion or the constitutive-open R429C mutation both reduce STIM1 binding to GRP75, suggesting that conformational changes in STIM1 play a role in this interaction. Deletion analysis revealed that the STIM1 (551-611) segment is crucial for GRP75 binding, as the peptide STIM1(551-611) binds GRP75, while STIM1(Δ551-611) shows reduced binding. These findings reveal a previously unrecognized role of STIM1 in direct inter-organelle communication.
    Keywords:  Calcium; GRP75; MAM; Mitochondria; STIM1
    DOI:  https://doi.org/10.1038/s44318-026-00700-8
  3. Apoptosis. 2026 Feb 09. 31(2): 66
      Acute pancreatitis (AP) is a potentially life-threatening inflammatory disease whose severity is fundamentally shaped by the mode of pancreatic acinar cell death. Crucially, this cell fate decision is primarily governed by genetically encoded programs known as regulated cell death (RCD), including apoptosis, necroptosis, pyroptosis, ferroptosis, and autophagy-dependent death. Unlike accidental necrosis, RCD proceeds via specific signaling cascades. In AP, excessive RCD in pancreatic acinar cells drives local tissue injury and systemic inflammation, potentially leading to systemic inflammatory response and organ failure. Mitochondria are central integrators of these interconnected RCD pathways: pathological calcium overload and oxidative stress disrupt mitochondrial function, causing ATP depletion. These organelle failures precipitate cell death cascades and amplify inflammation. Damaged mitochondria release damage-associated molecular patterns (DAMPs), which further promote cytokine release and pancreatic injury. This review highlights key RCD signaling mechanisms in AP and their pathophysiological significance. Emerging therapeutic strategies include agents that stabilize mitochondrial integrity or inhibit RCD signaling, which have shown efficacy in experimental models. Therefore, targeting RCD-especially via mitochondrial protection-represents a promising approach to limit pancreatic damage and improve outcomes. To realize this potential, we conclude by outlining translational challenges, such as biomarker validation, and proposing future research directions to advance AP therapeutics.
    Keywords:  Acute pancreatitis; Apoptosis; Autophagy; Ferroptosis; Mitochondria; Mitochondrial dysfunction; Necroptosis; Pyroptosis; Regulated cell death
    DOI:  https://doi.org/10.1007/s10495-026-02288-0
  4. Nat Metab. 2026 Feb 11.
      From insects to mammals, essential brain functions, such as forming long-term memories (LTMs), increase metabolic activity in stimulated neurons to meet the energetic demand associated with brain activation. However, while impairing neuronal metabolism limits brain performance, whether expanding the metabolic capacity of neurons boosts brain function remains poorly understood. Here, we show that LTM formation of flies and mice can be enhanced by increasing mitochondrial metabolism in central memory circuits. By knocking down the mitochondrial Ca2+ exporter Letm1, we favour Ca2+ retention in the mitochondrial matrix of neurons due to reduction of mitochondrial H+/Ca2+ exchange. The resulting increase in mitochondrial Ca2+ over-activates mitochondrial metabolism in neurons of central memory circuits, leading to improved LTM storage in training paradigms in which wild-type counterparts of both species fail to remember. Our findings unveil an evolutionarily conserved mechanism that controls mitochondrial metabolism in neurons and indicate its involvement in shaping higher brain functions, such as LTM.
    DOI:  https://doi.org/10.1038/s42255-026-01451-w
  5. Cells. 2026 Jan 30. pii: 265. [Epub ahead of print]15(3):
      Myocardial ischemia represents a state of reduced coronary perfusion with oxygenated blood, insufficient to meet the metabolic demands of the myocardium. Both acute and chronic ischemia trigger a cascade of cellular events that lead to disturbances in ionic balance, mitochondrial function and energy metabolism. During ischemia, cardiomyocytes (CMs) shift from aerobic to anaerobic metabolism, resulting in adenosine triphosphate (ATP) depletion, loss of ionic homeostasis and calcium (Ca2+) overload that activate proteases, phospholipases and membrane damage. Reperfusion restores oxygen supply and prevents irreversible necrosis but paradoxically initiates additional injury in marginally viable myocardium. The reoxygenation phase induces excessive production of reactive oxygen species (ROS), endothelial dysfunction and a strong inflammatory response mediated by neutrophils, platelets and cytokines. Mitochondrial dysfunction and opening of the mitochondrial permeability transition pore (mPTP) further amplify oxidative stress and inflammation and trigger apoptosis and necroptosis. Understanding these intertwined cellular and molecular mechanisms remains essential for identifying novel therapeutic targets aimed at reducing reperfusion injury and improving myocardial recovery after ischemic events.
    Keywords:  ROS; apoptosis; mitochondrial dysfunction; myocardial ischemia; necroptosis; reperfusion injury
    DOI:  https://doi.org/10.3390/cells15030265
  6. bioRxiv. 2026 Feb 01. pii: 2026.01.28.702368. [Epub ahead of print]
      Mitochondria serve as central hubs for Ca 2+ signaling, which is critical for metabolism, intercellular communication, and cell fate determination. Mitochondrial Ca 2+ homeostasis is maintained through tightly coordinated influx and efflux processes, with NCLX long recognized as the primary Ca 2+ extruder operating via Na + /Ca 2+ exchange. Despite its physiological significance, the molecular basis of NCLX function has remained unclear. Here, we report cryo-EM structures of rat NCLX in cytosolic-facing occluded and open states. The central transmembrane (TM) module of NCLX comprises 10 helices organized into two structurally similar halves with inverted orientations. Two characteristic α-repeats form a central ion-binding pocket, while peripheral TMs 1 and 6 are loosely associated with the core, likely mediating alternative access to the binding site. These structural features closely resemble those of NCXs, revealing a conserved mechanism underlying ion exchange. While NCLX retains the canonical Ca 2+ -binding site, it lacks several key Na + -binding residues found in NCXs, suggesting it functions as a non-selective cation/Ca 2+ exchanger. Consistent with this, cell-based Ca 2+ uptake assays show that NCLX mediates slower Ca 2+ exchange than NCX and can utilize Na + , K + , Li + , and potentially protons as counterions. Leveraging the structural symmetry of NCLX and its bidirectional exchange capability, we propose a model for the matrix-facing state and an alternating-access mechanism in which the sliding-door motions of TMs 1 and 6 enable ion access from cytosolic and matrix sides, analogous to NCX. These findings provide a structural and mechanistic framework for understanding mitochondrial NCLX function.
    DOI:  https://doi.org/10.64898/2026.01.28.702368
  7. Sci Rep. 2026 Feb 12.
      Pancortin (PCT), a protein highly expressed in the cortex during neurodevelopment, comprises four isoforms (PCT1-4) characterized by a central B-region and N-termini (A1/A2) and C-termini (C1/C2). While PCT2, enriched in adult mouse cortex, mediates ischemic neuronal death via interactions with WAVE1 and Bcl-xL, perinatal isoforms (A2-PCTs, namely PCT3 and PCT4) remain poorly defined. Given the vulnerability of the developing brain to hypoxia-induced neurological deficits, here we asked whether A2-PCTs contribute to ischemic damage in the developing cortex. In primary cortical neurons, knockdown of PCTs mitigated cell death induced by oxygen-glucose deprivation. Consistently, using A2-PCTs knockout mice subjected to middle cerebral artery occlusion, we observed significantly reduced cortical damage in younger animals, implicating A2-PCTs as pro-death factors in hypoxic conditions. Mechanistically, A2-PCTs formed a tripartite complex with Bcl-xL and WAVE1. Overexpression of A2-PCTs in HEK293 cells resulted in elevated cell mortality, and as revealed by SPLICS (a split-GFP-based contact site sensor)-based imaging of mitochondria-ER contact sites (MERCs), increased its localization to MERCs. Furthermore, A2-PCTs interacted with GRP75, a MERCs-tethering protein, in a Bcl-xL/WAVE1-dependent manner. A2-PCTs/Bcl-xL/WAVE1 complex increased IP3R-mediated calcium transfer from the ER to mitochondria, leading to cytosolic and mitochondrial calcium overload, which was attenuated by IP3R inhibition. In Neuro2a cells subjected to oxygen-glucose deprivation, PCTs knockdown similarly suppressed pathological calcium flux. Our study identifies A2-PCTs as key regulators of MERCs-mediated calcium dysregulation in neonatal stroke, pointing to their potential as therapeutic targets for mitigating ischemic brain injury in the developing brain.
    DOI:  https://doi.org/10.1038/s41598-026-38928-3
  8. J Transl Med. 2026 Feb 07.
      
    Keywords:  Aging; Cancer; Cardiovascular diseases; IBD; Inflammation; Mitochondria; Mitochondria targeted-therapy; Neurodegenerative diseases; ROS; Respiratory diseases; mtDNA
    DOI:  https://doi.org/10.1186/s12967-026-07783-1