bims-miptne 2024-03-03 papers

bims-miptne

Biomed News

on Mitochondrial permeability transition pore-dependent necrosis

Issue of 2024–03–03
eight papers selected by
Oluwatobi Samuel Adegbite, University of Liverpool

Coordinated metabolic responses to cyclophilin D deletion in the developing heart.
Elevations in the Mitochondrial Matrix Protein Cyclophilin D Correlate With Reduced Parvalbumin Expression in the Prefrontal Cortex of Patients With Schizophrenia.
The E3 ubiquitin ligase MARCH2 protects against myocardial ischemia-reperfusion injury through inhibiting pyroptosis via negative regulation of PGAM5/MAVS/NLRP3 axis.
Mitochondrial bioenergetics, metabolism, and beyond in pancreatic β-cells and diabetes.
Mitochondrial fumarate promotes ischemia/reperfusion-induced tubular injury.
Recent Advances in Our Understanding of Age-Related Macular Degeneration: Mitochondrial Dysfunction, Redox Signaling, and the Complement System.
Telomerase inhibitors induce mitochondrial oxidation and DNA damage-dependent cell death rescued by Bcl-2/Bcl-xL.
A comparative study of apoptosis, pyroptosis, necroptosis, and PANoptosis components in mouse and human cells.

iScience. 2024 Mar 15. 27(3): 109157

Coordinated metabolic responses to cyclophilin D deletion in the developing heart.

Gisela Beutner, Jonathan Ryan Burris, Michael P Collins, Chaitanya A Kulkarni, Sergiy M Nadtochiy, Karen L de Mesy Bentley, Ethan D Cohen, Paul S Brookes, George A Porter.

  In the embryonic heart, the activation of the mitochondrial electron transport chain (ETC) coincides with the closure of the cyclophilin D (CypD) regulated mitochondrial permeability transition pore (mPTP). However, it remains to be established whether the absence of CypD has a regulatory effect on mitochondria during cardiac development. Using a variety of assays to analyze cardiac tissue from wildtype and CypD knockout mice from embryonic day (E)9.5 to adult, we found that mitochondrial structure, function, and metabolism show distinct transitions. Deletion of CypD altered the timing of these transitions as the mPTP was closed at all ages, leading to coupled ETC activity in the early embryo, decreased citrate synthase activity, and an altered metabolome particularly after birth. Our results suggest that manipulating CypD activity may control myocyte proliferation and differentiation and could be a tool to increase ATP production and cardiac function in immature hearts.

Keywords:  Biological sciences; Cell biology; Metabolomics; Physiology

DOI:  https://doi.org/10.1016/j.isci.2024.109157
Schizophr Bull. 2024 Feb 27. pii: sbae016. [Epub ahead of print]

Elevations in the Mitochondrial Matrix Protein Cyclophilin D Correlate With Reduced Parvalbumin Expression in the Prefrontal Cortex of Patients With Schizophrenia.

John T O'Brien, Sophia P Jalilvand, Neha A Suji, Rohan K Jupelly, Aarron Phensy, Juliet M Mwirigi, Hajira Elahi, Theodore J Price, Sven Kroener.

   BACKGROUND AND HYPOTHESIS: Cognitive deficits in schizophrenia are linked to dysfunctions of the dorsolateral prefrontal cortex (DLPFC), including alterations in parvalbumin (PV)-expressing interneurons (PVIs). Redox dysregulation and oxidative stress may represent convergence points in the pathology of schizophrenia, causing dysfunction of GABAergic interneurons and loss of PV. Here, we show that the mitochondrial matrix protein cyclophilin D (CypD), a critical initiator of the mitochondrial permeability transition pore (mPTP) and modulator of the intracellular redox state, is altered in PVIs in schizophrenia.
STUDY DESIGN: Western blotting was used to measure CypD protein levels in postmortem DLPFC specimens of schizophrenic patients (n = 27) and matched comparison subjects with no known history of psychiatric or neurological disorders (n = 26). In a subset of this cohort, multilabel immunofluorescent confocal microscopy with unbiased stereological sampling methods were used to quantify (1) numbers of PVI across the cortical mantle (20 unaffected comparison, 14 schizophrenia) and (2) PV and CypD protein levels from PVIs in the cortical layers 2-4 (23 unaffected comparison, 18 schizophrenia).
STUDY RESULTS: In schizophrenic patients, the overall number of PVIs in the DLPFC was not significantly altered, but in individual PVIs of layers 2-4 PV protein levels decreased along a superficial-to-deep gradient when compared to unaffected comparison subjects. These laminar-specific PVI alterations were reciprocally linked to significant CypD elevations both in PVIs and total DLPFC gray matter.
CONCLUSIONS: Our findings support previously reported PVI anomalies in schizophrenia and suggest that CypD-mediated mPTP formation could be a potential contributor to PVI dysfunction in schizophrenia.

Keywords:  CypD; mitochondria; oxidative stress; parvalbumin; schizophrenia

DOI:  https://doi.org/10.1093/schbul/sbae016
Cell Discov. 2024 Feb 27. 10(1): 24

The E3 ubiquitin ligase MARCH2 protects against myocardial ischemia-reperfusion injury through inhibiting pyroptosis via negative regulation of PGAM5/MAVS/NLRP3 axis.

Shuolin Liu, Yaguang Bi, Tianting Han, Yiran E Li, Qihang Wang, Ne Natalie Wu, Chenguo Xu, Junbo Ge, Ronggui Hu, Yingmei Zhang.

Inflammasome activation and pyroptotic cell death are known to contribute to the pathogenesis of cardiovascular diseases, such as myocardial ischemia-reperfusion (I/R) injury, although the underlying regulatory mechanisms remain poorly understood. Here we report that expression levels of the E3 ubiquitin ligase membrane-associated RING finger protein 2 (MARCH2) were elevated in ischemic human hearts or mouse hearts upon I/R injury. Genetic ablation of MARCH2 aggravated myocardial infarction and cardiac dysfunction upon myocardial I/R injury. Single-cell RNA-seq analysis suggested that loss of MARCH2 prompted activation of NLRP3 inflammasome in cardiomyocytes. Mechanistically, phosphoglycerate mutase 5 (PGAM5) was found to act as a novel regulator of MAVS-NLRP3 signaling by forming liquid-liquid phase separation condensates with MAVS and fostering the recruitment of NLRP3. MARCH2 directly interacts with PGAM5 to promote its K48-linked polyubiquitination and proteasomal degradation, resulting in reduced PGAM5-MAVS co-condensation, and consequently inhibition of NLRP3 inflammasome activation and cardiomyocyte pyroptosis. AAV-based re-introduction of MARCH2 significantly ameliorated I/R-induced mouse heart dysfunction. Altogether, our findings reveal a novel mechanism where MARCH2-mediated ubiquitination negatively regulates the PGAM5/MAVS/NLRP3 axis to protect against cardiomyocyte pyroptosis and myocardial I/R injury.

DOI: https://doi.org/10.1038/s41421-023-00622-3
Front Mol Biosci. 2024 ;11 1354199

Mitochondrial bioenergetics, metabolism, and beyond in pancreatic β-cells and diabetes.

Alejandra María Rivera Nieves, Brian Michael Wauford, Accalia Fu.

  In Type 1 and Type 2 diabetes, pancreatic β-cell survival and function are impaired. Additional etiologies of diabetes include dysfunction in insulin-sensing hepatic, muscle, and adipose tissues as well as immune cells. An important determinant of metabolic health across these various tissues is mitochondria function and structure. This review focuses on the role of mitochondria in diabetes pathogenesis, with a specific emphasis on pancreatic β-cells. These dynamic organelles are obligate for β-cell survival, function, replication, insulin production, and control over insulin release. Therefore, it is not surprising that mitochondria are severely defective in diabetic contexts. Mitochondrial dysfunction poses challenges to assess in cause-effect studies, prompting us to assemble and deliberate the evidence for mitochondria dysfunction as a cause or consequence of diabetes. Understanding the precise molecular mechanisms underlying mitochondrial dysfunction in diabetes and identifying therapeutic strategies to restore mitochondrial homeostasis and enhance β-cell function are active and expanding areas of research. In summary, this review examines the multidimensional role of mitochondria in diabetes, focusing on pancreatic β-cells and highlighting the significance of mitochondrial metabolism, bioenergetics, calcium, dynamics, and mitophagy in the pathophysiology of diabetes. We describe the effects of diabetes-related gluco/lipotoxic, oxidative and inflammation stress on β-cell mitochondria, as well as the role played by mitochondria on the pathologic outcomes of these stress paradigms. By examining these aspects, we provide updated insights and highlight areas where further research is required for a deeper molecular understanding of the role of mitochondria in β-cells and diabetes.

Keywords:  Type 1 diabetes, Type 2 Diabetes, mitochondria; bioenergetics; calcium; insulin secretion; metabolism; pancreatic beta cells

DOI:  https://doi.org/10.3389/fmolb.2024.1354199
Acta Physiol (Oxf). 2024 Feb 26. e14121

Mitochondrial fumarate promotes ischemia/reperfusion-induced tubular injury.

Zuo-Lin Li, Ming-Min Huang, Meng-Yao Yu, Di-Fei Nie, Sha-Li Fu, Jing-Jing Di, Ting Lan, Bi-Cheng Liu, Qiu-Li Wu.

   AIM: Mitochondrial dysfunction, a characteristic pathological feature of renal Ischemic/reperfusion injury (I/RI), predisposes tubular epithelial cells to maintain an inflammatory microenvironment, however, the exact mechanisms through which mitochondrial dysfunction modulates the induction of tubular injury remains incompletely understood.
METHODS: ESI-QTRAP-MS/MS approach was used to characterize the targeted metabolic profiling of kidney with I/RI. Tubule injury, mitochondrial dysfunction, and fumarate level were evaluated using qPCR, transmission electron microscopy, ELISA, and immunohistochemistry.
RESULTS: We demonstrated that tubule injury occurred at the phase of reperfusion in murine model of I/RI. Meanwhile, enhanced glycolysis and mitochondrial dysfunction were found to be associated with tubule injury. Further, we found that tubular fumarate, which resulted from fumarate hydratase deficiency and released from dysfunctional mitochondria, promoted tubular injury. Mechanistically, fumarate induced tubular injury by causing disturbance of glutathione (GSH) hemostasis. Suppression of GSH with buthionine sulphoximine administration could deteriorate the fumarate inhibition-mediated tubule injury recovery. Reactive oxygen species/NF-κB signaling activation played a vital role in fumarate-mediated tubule injury.
CONCLUSION: Our studies demonstrated that the mitochondrial-derived fumarate promotes tubular epithelial cell injury in renal I/RI. Blockade of fumarate-mediated ROS/NF-κB signaling activation may serve as a novel therapeutic approach to ameliorate hypoxic tubule injury.

Keywords:  fumarate; glutathione; ischemia/reperfusion; mitochondria; tubule injury

DOI:  https://doi.org/10.1111/apha.14121
Aging Dis. 2024 Feb 27.

Recent Advances in Our Understanding of Age-Related Macular Degeneration: Mitochondrial Dysfunction, Redox Signaling, and the Complement System.

Francesco Buonfiglio, Christina A Korb, Bernhard Stoffelns, Norbert Pfeiffer, Adrian Gericke.

Age-related macular degeneration (AMD) is a prevalent degenerative disorder of the central retina, which holds global significance as the fourth leading cause of blindness. The condition is characterized by a multifaceted pathophysiology that involves aging, oxidative stress, inflammation, vascular dysfunction, and complement activation. The complex interplay of these factors contributes to the initiation and progression of AMD. Current treatments primarily address choroidal neovascularization (CNV) in neovascular AMD. However, the approval of novel drug therapies for the atrophic and more gradual variant, known as geographic atrophy (GA), has recently occurred. In light of the substantial impact of AMD on affected individuals' quality of life and the strain it places on healthcare systems, there is a pressing need for innovative medications. This paper aims to provide an updated and comprehensive overview of advancements in our understanding of the etiopathogenesis of AMD. Special attention will be given to the influence of aging and altered redox status on mitochondrial dynamics, cell death pathways, and the intricate interplay between oxidative stress and the complement system, specifically in the context of GA. Additionally, this review will shed light on newly approved therapies and explore emerging alternative treatment strategies in the field. The objective is to contribute to the ongoing dialogue surrounding AMD, offering insights into the latest developments that may pave the way for more effective management and intervention approaches.

DOI: https://doi.org/10.14336/AD.2024.0124
Int J Biol Macromol. 2024 Feb 23. pii: S0141-8130(24)00954-1. [Epub ahead of print] 130151

Telomerase inhibitors induce mitochondrial oxidation and DNA damage-dependent cell death rescued by Bcl-2/Bcl-xL.

Aparna Geetha Jayaprasad, Aneesh Chandrasekharan, S P Arun Jyothi, S M John Sam, T R Santhoshkumar, M Radhakrishna Pillai.

   BACKGROUND: Reactivation of telomerase is a hallmark of cancer and the majority of cancers over-express telomerase. Telomerase-dependent telomere length maintenance confers immortality to cancer cells. However, telomere length-independent cell survival functions of telomerase also play a critical role in tumorigenesis. Multiple telomerase inhibitors have been developed as therapeutics and include anti-sense oligonucleotides, telomerase RNA component targeting agents, chemical inhibitors of telomerase, small molecule inhibitors of hTERT, and telomerase vaccine. In general, telomerase inhibitors affect cell proliferation and survival of cells depending on the telomere length reduction, culminating in replicative senescence or cell death by crisis. However, most telomerase inhibitors kill cancer cells prior to significant reduction in telomere length, suggesting telomere length independent role of telomerase in early telomere dysfunction-dependent cell death.
METHODS: In this study, we explored the mechanism of cell death induced by three prominent telomerase inhibitors utilizing a series of genetically encoded sensor cells including redox and DNA damage sensor cells.
RESULTS: We report that telomerase inhibitors induce early cell cycle inhibition, followed by redox alterations at cytosol and mitochondria. Massive mitochondrial oxidation and DNA damage induce classical cell death involving mitochondrial transmembrane potential loss and mitochondrial permeabilization. Real-time imaging of the progression of mitochondrial oxidation revealed that treated cells undergo a biphasic mitochondrial redox alteration during telomerase inhibition, emphasizing the potential role of telomerase in the redox regulation at mitochondria. Additionally, silencing of hTERT confirmed its predominant role in maintaining mitochondrial redox homeostasis. Interestingly, the study also demonstrated that anti-apoptotic Bcl-2 family proteins still confer protection against cell death induced by telomerase inhibitors.
CONCLUSION: The study demonstrates that redox alterations and DNA damage contribute to early cell death by telomerase inhibitors and anti-apoptotic Bcl-2 family proteins confer protection from cell death by their ability to safeguard mitochondria from oxidation damage.

Keywords:  Apoptosis; Mitochondrial damage; Mitochondrial permeabilization; Redox alterations; Telomerase inhibition

DOI:  https://doi.org/10.1016/j.ijbiomac.2024.130151
PLoS One. 2024 ;19(2): e0299577

A comparative study of apoptosis, pyroptosis, necroptosis, and PANoptosis components in mouse and human cells.

Sk Mohiuddin Choudhury, Roman Sarkar, Rajendra Karki, Thirumala-Devi Kanneganti.

Regulated cell death is a key component of the innate immune response, which provides the first line of defense against infection and homeostatic perturbations. However, cell death can also drive pathogenesis. The most well-defined cell death pathways can be categorized as nonlytic (apoptosis) and lytic (pyroptosis, necroptosis, and PANoptosis). While specific triggers are known to induce each of these cell death pathways, it is unclear whether all cell types express the cell death proteins required to activate these pathways. Here, we assessed the protein expression and compared the responses of immune and non-immune cells of human and mouse origin to canonical pyroptotic (LPS plus ATP), apoptotic (staurosporine), necroptotic (TNF-α plus z-VAD), and PANoptotic (influenza A virus infection) stimuli. When compared to fibroblasts, both mouse and human innate immune cells, macrophages, expressed higher levels of cell death proteins and activated cell death effectors more robustly, including caspase-1, gasdermins, caspase-8, and RIPKs, in response to specific stimuli. Our findings highlight the importance of considering the cell type when examining the mechanisms regulating inflammation and cell death. Improved understanding of the cell types that contain the machinery to execute different forms of cell death and their link to innate immune responses is critical to identify new strategies to target these pathways in specific cellular populations for the treatment of infectious diseases, inflammatory disorders, and cancer.

DOI: https://doi.org/10.1371/journal.pone.0299577