bims-mitmed 2025-05-25 papers

bims-mitmed

Biomed News

on Mitochondrial medicine

Issue of 2025–05–25
27 papers selected by
Dario Brunetti, Fondazione IRCCS Istituto Neurologico

Modelling POLG mutations in mice unravels a critical role of POLγΒ in regulating phenotypic severity.
Caspase-11 drives macrophage hyperinflammation in models of Polg-related mitochondrial disease.
Gene therapy prevents onset of mitochondrial cardiomyopathy in neonatal mice with Ndufs6 deficiency.
SMIM20 promotes complex IV biogenesis and Ca2+ signaling in mice heart.
De novo serine biosynthesis is protective in mitochondrial disease.
Silencing mitochondrial gene expression in living cells.
Therapeutic implications of mitochondrial transfer on stem cell fate in regenerative medicine.
Inhibition of Rho-associated kinases ROCK1 and ROCK2 as a Therapeutic Strategy to Reactivate the Repressed FXN Gene in Friedreich Ataxia.
Improvement of mitochondrial function in Duchenne muscular dystrophy skeletal muscle cells by coenzyme Q10 delivery to mitochondria.
Mitochondrial dysfunction in epilepsy: mechanistic insights and clinical strategies.
Untargeted proteomics enables ultra-rapid variant prioritisation in mitochondrial and other rare diseases.
Hepatic glutamic-oxaloacetic transaminase (GOT2) promotes mitochondrial respiration energized at complex II and alters whole body metabolism.
Dose-dependent CHCHD10 dysregulation dictates motor neuron disease severity and alters creatine metabolism.
Mechanistic insights into Bcs1-mediated mitochondrial membrane translocation of the folded Rieske protein.
Analysis of the Expression and Complexes Assembly of the Mitochondrial Respiratory Chain Proteins in the Fission Yeast Schizosaccharomyces pombe.
Neuromagnetic responses to multimodal stimuli in Friedreich's ataxia.
Overview of methods that determine mitochondrial function in human disease.
Human mitochondrial ferritin exhibits highly unusual iron-O2 chemistry distinct from that of cytosolic ferritins.
From powerhouse to modulator: regulating immune system responses through intracellular mitochondrial transfer.
Mitochondrial Bioenergetics in Physiology.
Adaptation of mitochondrial bioenergetics to coenzyme Q deficiency in human endothelial cells after chronic exposure to bisphosphonates.
Miro1: A potential target for treating neurological disorders.
M2 microglia-derived exosomes reduce neuronal ferroptosis via FUNDC1-mediated mitophagy by activating AMPK/ULK1 signaling.
Optimized AAV capsids for basal ganglia diseases show robust potency and distribution.
Shaping the waves: Mitochondrial regulation of calcium oscillations in smooth muscle.
LoxCode in vivo barcoding reveals epiblast clonal fate bias to fetal organs.
Endocrine manifestations and long-term outcomes of patients with mitochondrial diseases.

Nat Commun. 2025 May 23. 16(1): 4782

Modelling POLG mutations in mice unravels a critical role of POLγΒ in regulating phenotypic severity.

Samantha Corrà, Alessandro Zuppardo, Sebastian Valenzuela, Louise Jenninger, Raffaele Cerutti, Sirelin Sillamaa, Emily Hoberg, Katarina A S Johansson, Urska Rovsnik, Sara Volta, Pedro Silva-Pinheiro, Hannah Davis, Aleksandra Trifunovic, Michal Minczuk, Claes M Gustafsson, Anu Suomalainen, Massimo Zeviani, Bertil Macao, Xuefeng Zhu, Maria Falkenberg, Carlo Viscomi.

DNA polymerase γ (POLγ), responsible for mitochondrial DNA replication, consists of a catalytic POLγA subunit and two accessory POLγB subunits. Mutations in POLG, which encodes POLγA, lead to various mitochondrial diseases. We investigated the most common POLG mutations (A467T, W748S, G848S, Y955C) by characterizing human and mouse POLγ variants. Our data reveal that these mutations significantly impair POLγ activities, with mouse variants exhibiting milder defects. Cryogenic electron microscopy highlighted structural differences between human and mouse POLγ, particularly in the POLγB subunit, which may explain the higher activity of mouse POLγ and the reduced severity of mutations in mice. We further generated a panel of mouse models mirroring common human POLG mutations, providing crucial insights into the pathogenesis of POLG-related disorders and establishing robust models for therapeutic development. Our findings emphasize the importance of POLγB in modulating the severity of POLG mutations.

DOI: https://doi.org/10.1038/s41467-025-60059-y
Nat Commun. 2025 May 20. 16(1): 4640

Caspase-11 drives macrophage hyperinflammation in models of Polg-related mitochondrial disease.

Jordyn J VanPortfliet, Yuanjiu Lei, Muthumeena Ramanathan, Camila Guerra Martinez, Jessica Wong, Tim J Stodola, Brian R Hoffmann, Kathryn Pflug, Raquel Sitcheran, Stephen C Kneeland, Stephen A Murray, Peter J McGuire, Carolyn L Cannon, A Phillip West.

Mitochondrial diseases (MtD) represent a significant public health challenge due to their heterogenous clinical presentation, often severe and progressive symptoms, and lack of effective therapies. Environmental exposures, such bacterial and viral infection, can further compromise mitochondrial function and exacerbate the progression of MtD. However, the underlying immune alterations that enhance immunopathology in MtD remain unclear. Here we employ in vitro and in vivo approaches to clarify the molecular and cellular basis for innate immune hyperactivity in models of polymerase gamma (Polg)-related MtD. We reveal that type I interferon (IFN-I)-mediated upregulation of caspase-11 and guanylate-binding proteins (GBP) increase macrophage sensing of the opportunistic microbe Pseudomonas aeruginosa (PA) in Polg mutant mice. Furthermore, we show that excessive cytokine secretion and activation of pyroptotic cell death pathways contribute to lung inflammation and morbidity after infection with PA. Our work provides a mechanistic framework for understanding innate immune dysregulation in MtD and reveals potential targets for limiting infection- and inflammation-related complications in Polg-related MtD.

DOI: https://doi.org/10.1038/s41467-025-59907-8
Cell Death Discov. 2025 May 22. 11(1): 249

Gene therapy prevents onset of mitochondrial cardiomyopathy in neonatal mice with Ndufs6 deficiency.

Xiaoxian Zhang, Li Huang, Cheng Li, Jinjuan Yang, Fuyu Duan, Qiang Su, Yuelin Zhang, Meng Kou, Xiaoya Zhou, Liyan Guo, Shaoxiang Chen, Yongxia Niu, Ziyue Li, Sihua Ou, Min Zhang, Kenneth King-Yip Cheng, Jianlong Wu, Xiang Xu, Qizhou Lian.

Mutations in genes affecting mitochondrial complex I (CI) can lead to mitochondrial cardiomyopathy (MCM) yet no effective treatment. This study sought to determine whether adeno-associated virus 9 (AAV9)-based gene therapy could prevent or rescue Ndufs6 deficiency-induced MCM at different disease stages. Using Ndufs6gt/gt mice to mimic MCM, cardiac dysfunction was evident at week 4 post-birth, showing reduced ejection fraction, CI activity, increased fibrosis, mitochondrial fission, and disrupted cristae. Neonatal and adult mice were intravenously given AAV9-hNdufs6 (1e14 vg kg-1). AAV9-hNdufs6 therapy effectively prevented neonatal mice's cardiac dysfunction onset, preserving CI activity and cristae structure for 11 months. In contrast, therapy in adult mice post-disease onset failed to reverse or halt progression of heart dilation and failure after 3 months, showing mitochondrial abnormalities and cardiomyocyte apoptosis. Mechanistically, adult mouse Kupffer cells demonstrated enhanced phagocytic capabilities compared to neonatal mice, with higher expression levels of AAV9 cell surface receptors observed in neonatal mouse hearts, rendering neonatal mice more responsive to AAV9-mediated gene therapy for heart tissue. Additionally, AAV9-hNdufs6 gene therapy initiated at an early stage increased Ndufs6 expression in cardiac tissue, preserved mitochondrial structure and function, prevented cardiomyocyte fibrosis through modulation of the AMPK/Drp1 signaling pathway. In conclusion, early intervention with AAV9-hNdufs6 gene therapy can effectively prevent the onset of MCM, but intervention after disease onset has limited efficacy.

DOI: https://doi.org/10.1038/s41420-025-02524-7
Cell Rep. 2025 May 20. pii: S2211-1247(25)00494-2. [Epub ahead of print]44(6): 115723

SMIM20 promotes complex IV biogenesis and Ca2+ signaling in mice heart.

Angela Boshnakovska, Julius Ryan Pronto, Tanja Gall, Abhishek Aich, Jan Prochazka, Zuzana Nichtova, Radislav Sedlacek, Izzatullo Sobitov, Sofia Ainatzi, Christof Lenz, Dörthe M Katschinski, Henning Urlaub, Niels Voigt, Peter Rehling, Laura S Kremer.

  Mitochondria are key to cellular energetics, metabolism, and signaling. Their dysfunction is linked to devastating diseases, including mitochondrial disorders, diabetes, neurodegenerative diseases, cardiac disorders, and cancer. Here, we present a knockout mouse model lacking the complex IV assembly factor SMIM20/MITRAC7. SMIM20-/- mice display cardiac pathology with reduced heart weight and cardiac output. Heart mitochondria present with reduced levels of complex IV associated with increased complex I activity, have altered fatty acid oxidation, and display elevated levels of ROS production. Interestingly, mutant mouse ventricular myocytes show unphysiological Ca2+ handling, which can be attributed to the increase in mitochondrial ROS production. Our study presents an example of a tissue-specific phenotype in the context of OXPHOS dysfunction. Moreover, our data suggest a link between complex IV dysfunction and Ca2+ handling at the endoplasmic reticulum through ROS signaling.

Keywords:  CP: Cell biology; CP: Molecular biology; OXPHOS; assembly factor; cytochrome c oxidase; mitochondria; mitochondrial disease

DOI:  https://doi.org/10.1016/j.celrep.2025.115723
Cell Rep. 2025 May 15. pii: S2211-1247(25)00481-4. [Epub ahead of print]44(5): 115710

De novo serine biosynthesis is protective in mitochondrial disease.

Christopher B Jackson, Anastasiia Marmyleva, Geoffray Monteuuis, Ryan Awadhpersad, Takayuki Mito, Nicola Zamboni, Takashi Tatsuta, Amy E Vincent, Liya Wang, Nahid A Khan, Thomas Langer, Christopher J Carroll, Anu Suomalainen.

  The importance of serine as a metabolic regulator is well known for tumors and is also gaining attention in degenerative diseases. Recent data indicate that de novo serine biosynthesis is an integral component of the metabolic response to mitochondrial disease, but the roles of the response have remained unknown. Here, we report that glucose-driven de novo serine biosynthesis maintains metabolic homeostasis in energetic stress. Pharmacological inhibition of the rate-limiting enzyme, phosphoglycerate dehydrogenase (PHGDH), aggravated mitochondrial muscle disease, suppressed oxidative phosphorylation and mitochondrial translation, altered whole-cell lipid profiles, and enhanced the mitochondrial integrated stress response (ISRmt) in vivo in skeletal muscle and in cultured cells. Our evidence indicates that de novo serine biosynthesis is essential to maintain mitochondrial respiration, redox balance, and cellular lipid homeostasis in skeletal muscle with mitochondrial dysfunction. Our evidence implies that interventions activating de novo serine synthesis may protect against mitochondrial failure in skeletal muscle.

Keywords:  CP: Metabolism; de novo serine synthesis; mitochondrial disease; mitochondrial integrated stress response; mitochondrial translation; tissue specificity; treatment

DOI:  https://doi.org/10.1016/j.celrep.2025.115710
Science. 2025 May 22. eadr3498

Silencing mitochondrial gene expression in living cells.

Luis Daniel Cruz-Zaragoza, Drishan Dahal, Mats Koschel, Angela Boshnakovska, Aiturgan Zheenbekova, Mehmet Yilmaz, Marcel Morgenstern, Jan-Niklas Dohrke, Julian Bender, Anusha Valpadashi, Kristine A Henningfeld, Silke Oeljeklaus, Laura Sophie Kremer, Mirjam Breuer, Oliver Urbach, Sven Dennerlein, Michael Lidschreiber, Stefan Jakobs, Bettina Warscheid, Peter Rehling.

Mitochondria fulfill central functions in metabolism and energy supply. They express their own genome, which encodes key subunits of the oxidative phosphorylation system. However, central mechanisms underlying mitochondrial gene expression remain enigmatic. A lack of suitable technologies to target mitochondrial protein synthesis in cells has limited experimental access. Here, we silenced the translation of specific mitochondrial mRNAs in living human cells by delivering synthetic peptide-morpholino chimeras. This approach allowed us to perform a comprehensive temporal monitoring of cellular responses. Our study provides insights into mitochondrial translation, its integration into cellular physiology, and provides a strategy to address mitochondrial gene expression in living cells. The approach can potentially be used to analyze mechanisms and pathophysiology of mitochondrial gene expression in a range of cellular model systems.

DOI: https://doi.org/10.1126/science.adr3498
J Transl Med. 2025 May 21. 23(1): 568

Therapeutic implications of mitochondrial transfer on stem cell fate in regenerative medicine.

Ying Liu, Waruna Lakmal Dissanayaka, Cynthia Yiu.

  With the discovery of intercellular mitochondrial transfer, the intricate mitochondrial regulatory networks on stem cell fate have aroused intense academic interest. Apart from capturing freely released mitochondria from donor cells, stem cells are able to receive mitochondria through tunneling nanotubes (TNTs), gap junctional channels (GJCs) and extracellular vesicles (EVs), especially when undergoing stressful conditions such as inflammation, hypoxia, chemotherapy drug exposure, and irradiation. Stem cells that are potentiated by exogenous mitochondria show enhanced potential for proliferation, differentiation, and immunomodulation. The well-tolerated nature of either autogenous or allogenous mitochondria when locally injected in the human ischemic heart has validated the safety and therapeutic potential of mitochondrial transplantation. In children diagnosed with mitochondrial DNA deletion syndrome, functional improvements have been observed when empowering their hematopoietic stem cells with maternally derived mitochondria. Apart from the widely investigated applications of mitochondrial transfer in ischemia-reperfusion injury, neurodegenerative diseases and mitochondrial diseases etc., therapeutic potentials of mitochondrial transfer in tissue repair and regeneration are equally noteworthy, though there has been no systematic summary in this regard.This review analyzed the research and development trends of mitochondrial transfer in stem cells and regenerative medicine over the past decade from a bibliometric perspective, introduced the concept and associated mechanisms of mitochondrial transfer, summarized the regulations of intercellular mitochondrial transfer on stem cell fate. Finally, the therapeutic application of mitochondrial transplantation in diseases and tissue regeneration has been reviewed, including recent clinical studies related to mitochondrial transplantation.Mitochondrial transfer shows promise in modifying and reshaping the cellular properties of stem cells, making them more conducive to regeneration. Mesenchymal stem cells (MSCs)-derived mitochondria have shown multifaceted potential in promoting the revitalization and regeneration of cardiac, cutaneous, muscular, neuronal tissue. This review integrates novel research findings on mitochondrial transfer in stem cell biology and regenerative medicine, emphasizing the crucial translational value of mitochondrial transfer in regeneration. It serves to underscore the significant impact of mitochondrial transfer and provides a valuable reference for further exploration in this field.

Keywords:  Mitochondrial therapeutics; Mitochondrial transfer; Regenerative medicine; Stem cell fate; Tissue repair

DOI:  https://doi.org/10.1186/s12967-025-06472-9
J Neurosci. 2025 May 22. pii: e2307242025. [Epub ahead of print]

Inhibition of Rho-associated kinases ROCK1 and ROCK2 as a Therapeutic Strategy to Reactivate the Repressed FXN Gene in Friedreich Ataxia.

Minggang Fang, Shahid Banday, Sara K Deibler, Tessa M Simone, Madison Coleman, Emerald O'Connor, Rui Li, Lihua Julie Zhu, Michael R Green.

Friedreich ataxia (FA) is an autosomal recessive disease characterized by progressive damage to the nervous system and severe cardiac abnormalities. The disease is caused by a GAA•TTC triplet repeat expansion in the first intron of the FXN gene, which results in epigenetic repression of FXN transcription and reduction in FXN (frataxin) protein which results in mitochondrial dysfunction. Factors and pathways that promote FXN repression represent potential therapeutic targets whose inhibition would restore FXN transcription and frataxin protein levels. Here, we performed a candidate-based RNAi screen to identify kinases, a highly druggable class of proteins, that when knocked down upregulate FXN expression. Using this approach, we identified Rho kinase ROCK1 as a critical factor required for FXN repression. ShRNA-mediated knockdown of ROCK1, or the related kinase ROCK2, increases FXN mRNA and frataxin protein levels in FA patient-derived induced pluripotent stem cells (iPSCs) and differentiated neurons and cardiomyocytes to levels observed in normal cells. We demonstrate that small molecule ROCK inhibitors, including the FDA-approved drug belumosudil and fasudil, reactivate FXN expression in cultured FA iPSCs, neurons, cardiomyocytes, and FA patient primary fibroblasts, and ameliorate the characteristic mitochondrial defects in these cell types. Remarkably, treatment of transgenic FA mice of both sexes with belumosudil or fasudil upregulates FXN expression, ameliorates the mitochondrial defects in the brain and heart tissues, and improves motor coordination and muscle strength. Collectively, our study identifies ROCK kinases as critical repressors of FXN expression and provides preclinical evidence that FDA approved ROCK inhibitors may be repurposed for treatment of FA.Significance Statement Friedreich ataxia is a debilitating disorder caused by epigenetic repression of the frataxin (FXN) gene, leading to neurodegeneration and cardiomyopathy. Through an RNA interference screen, we identified ROCK1 and ROCK2 kinases as critical repressors of FXN expression, making them promising therapeutic targets for upregulating FXN in patient-derived cells. Treatment with small-molecule ROCK inhibitors, including the FDA-approved drug belumosudil and clinically advanced fasudil, restores frataxin levels, alleviates mitochondrial defects, and improves disease phenotypes in cells and animal models. These findings establish ROCK kinases as targets for Friedreich ataxia therapy and open new avenues for repurposing existing ROCK inhibitors, warranting clinical exploration.

DOI: https://doi.org/10.1523/JNEUROSCI.2307-24.2025
Biochem Biophys Res Commun. 2025 May 17. pii: S0006-291X(25)00717-X. [Epub ahead of print]771 152003

Improvement of mitochondrial function in Duchenne muscular dystrophy skeletal muscle cells by coenzyme Q10 delivery to mitochondria.

Itsumi Sato, Daisuke Sasaki, Jiro Abe, Keitaro Yamanouchi, Atsuhito Takeda, Yuma Yamada.

  Duchenne muscular dystrophy (DMD) is a genetic disease, with no curative therapy, and is associated with mitochondrial dysfunction in skeletal muscle. Thus, mitochondrial treatment is a potential therapy for DMD. However, few studies have reported on such treatments because of the difficulty of drug delivery to mitochondria. Here, we used MITO-Porter to deliver coenzyme Q10 to the mitochondria of primary skeletal muscle cells isolated from DMD model rats. Our results show the therapeutic potential of mitochondrial activation for DMD.

Keywords:  Coenzyme Q(10); Decreased mitochondrial respiratory capacity; Drug delivery system; Duchenne muscular dystrophy; Nanoparticle; Skeletal muscle cell

DOI:  https://doi.org/10.1016/j.bbrc.2025.152003
Mol Biol Rep. 2025 May 20. 52(1): 470

Mitochondrial dysfunction in epilepsy: mechanistic insights and clinical strategies.

Xiaolu Zhang, Zhengjuan Wu, Xu Zhou, Hua Tao.

  Epilepsy is a common neurological disorder that is increasingly recognized for its significant association with mitochondrial dysfunction. This review explores the intricate relationship between mitochondrial dysfunction and epilepsy, highlighting the molecular mechanisms, diagnostic strategies, and therapeutic approaches involved. Mitochondrial abnormalities, including defects in the electron transport chain, impaired mitochondrial dynamics, disrupted autophagy, and increased oxidative stress, are implicated in epilepsy pathogenesis. The molecular mechanisms involve respiratory chain impairments, fission-fusion imbalances, inadequate mitophagy, and oxidative stress-induced neuronal excitability. The diagnosis of mitochondrial epilepsy requires a multifaceted approach, combining clinical assessment, biochemical testing, imaging, and genetic analysis, with a particular focus on mtDNA mutations. Therapeutic strategies include antiepileptic drugs with variable mitochondrial effects, the ketogenic diet, and emerging potential approaches such as antioxidants and mitochondrial-targeted therapies. Despite advances in understanding and treatment, challenges persist due to the complexity of mtDNA mutations and treatment resistance. Future directions involve gene-editing technologies, mitochondrial transplantation, and induced pluripotent stem cells, which hold promise for addressing the underlying defects and improving epilepsy management.

Keywords:  Epilepsy; Ketogenic diet; Mitochondria; Mutation; Oxidative stress

DOI:  https://doi.org/10.1007/s11033-025-10577-1
Genome Med. 2025 May 22. 17(1): 58

Untargeted proteomics enables ultra-rapid variant prioritisation in mitochondrial and other rare diseases.

MitoMDT Diagnostic Network for Genomics and Omics

   BACKGROUND: Only half of individuals with suspected rare diseases receive a genetic diagnosis following genomic testing. A genetic diagnosis allows access to appropriate care, restores reproductive confidence and reduces the number of potentially unnecessary interventions. A major barrier is the lack of disease agnostic functional tests suitable for implementation in routine diagnostics that can provide evidence supporting pathogenicity of novel variants, especially those refractory to RNA sequencing.
METHODS: Focusing on mitochondrial disease, we describe an untargeted mass-spectrometry based proteomics pipeline that can quantify proteins encoded by > 50% of Mendelian disease genes and > 80% of known mitochondrial disease genes in clinically relevant sample types, including peripheral blood mononuclear cells (PBMCs). In total we profiled > 90 individuals including undiagnosed individuals suspected of mitochondrial disease and a supporting cohort of disease controls harbouring pathogenic variants in nuclear and mitochondrial genes. Proteomics data were benchmarked against pathology accredited respiratory chain enzymology to assess the performance of proteomics as a functional test. Proteomics testing was subsequently applied to individuals with suspected mitochondrial disease, including a critically ill infant with a view toward rapid interpretation of variants identified in ultra-rapid genome sequencing.
RESULTS: Proteomics testing provided evidence to support variant pathogenicity in 83% of individuals in a cohort with confirmed mitochondrial disease, outperforming clinical respiratory chain enzymology. Freely available bioinformatic tools and criteria developed for this study ( https://rdms.app/ ) allow mitochondrial dysfunction to be identified in proteomics data with high confidence. Application of proteomics to undiagnosed individuals led to 6 additional diagnoses, including a mitochondrial phenocopy disorder, highlighting the disease agnostic nature of proteomics. Use of PBMCs as a sample type allowed rapid return of proteomics data supporting pathogenicity of novel variants identified through ultra-rapid genome sequencing in as little as 54 h.
CONCLUSIONS: This study provides a framework to support the integration of a single untargeted proteomics test into routine diagnostic practice for the diagnosis of mitochondrial and potentially other rare genetic disorders in clinically actionable timelines, offering a paradigm shift for the functional validation of genetic variants.

Keywords:  Genetic diagnostics; Mendelian disease; Proteomics; Ultra-rapid genome sequencing; Variant prioritisation

DOI:  https://doi.org/10.1186/s13073-025-01467-z
J Biol Chem. 2025 May 21. pii: S0021-9258(25)02111-8. [Epub ahead of print] 110261

Hepatic glutamic-oxaloacetic transaminase (GOT2) promotes mitochondrial respiration energized at complex II and alters whole body metabolism.

Brian D Fink, Ritu Som, Adam J Rauckhorst, Eric B Taylor, Liping Yu, William I Sivitz.

  The mitochondrial enzyme, glutamic-oxaloacetic transaminase (GOT2), catalyzes the reaction between oxaloacetate and glutamate generating aspartate and alpha-ketoglutarate (α-KG). Glutamate can also be directly converted to α-KG by glutamate dehydrogenase. We investigated mitochondrial and systemic effects of an inducible liver specific-mouse GOT2 knockout (KO). We observed no differences in body mass or percent fat mass in KO mice, however, KO mice had lower fasting glucose and liver tissue contained more fat. Respiration by liver mitochondria energized at complex II by succinate + glutamate was decreased in KO compared to wildtype (WT) mice at low inner membrane potential (ΔΨ) as induced by titration with ADP. Metabolite studies by NMR showed that at low versus high ΔΨ, GOT2KO mitochondria energized by succinate + glutamate generated more oxaloacetate (a potent inhibitor of succinate dehydrogenase, SDH) and less aspartate. Respiration and mitochondrial metabolites energized by pyruvate + malate or palmitoyl-carnitine + malate did not differ between KO and WT mice. Respiration by GOT2KO mitochondria energized by glutamate + malate was decreased at all levels of ΔΨ. Pathway analysis of LC-MS profile data in liver tissue of KO versus WT mice revealed differential enrichment of the malate aspartate shuttle, TCA cycle, aspartate metabolism, glutamate metabolism, and gluconeogenesis. In summary, GOT2KO impaired potential-dependent complex II energized O2 flux likely due at least in part to oxaloacetate inhibition of SDH.

Keywords:  Mitochondria; glutamic-oxaloacetic transaminase-2; liver; mitochondrial complex II; mitochondrial inner membrane potential; oxaloacetate; respiration; succinate dehydrogenase

DOI:  https://doi.org/10.1016/j.jbc.2025.110261
Acta Neuropathol Commun. 2025 May 22. 13(1): 111

Dose-dependent CHCHD10 dysregulation dictates motor neuron disease severity and alters creatine metabolism.

Sandra Harjuhaahto, Manu Jokela, Jayasimman Rajendran, Minea Rokka, Bowen Hu, Jouni Kvist, Fuping Zhang, Tomáš Zárybnický, Kimmo Haimilahti, Liliya Euro, Eija Pirinen, Nadine Huber, Sanna-Kaisa Herukka, Annakaisa Haapasalo, Emilia Kuuluvainen, Swetha Gopalakrishnan, Pekka Katajisto, Ville Hietakangas, Thibaut Burg, Ludo Van Den Bosch, Xiaoping Huang, Derek P Narendra, Satu Kuure, Emil Ylikallio, Henna Tyynismaa.

  Dominant defects in CHCHD10, a mitochondrial intermembrane space protein, lead to a range of neurological and muscle disease phenotypes including amyotrophic lateral sclerosis. Many patients present with spinal muscular atrophy Jokela type (SMAJ), which is caused by heterozygous p.G66V variant. While most disease variants lead to aggregation of CHCHD10 and activation of proteotoxic stress responses, the pathogenic mechanisms of the p.G66V variant are less clear. Here we report the first homozygous CHCHD10 patient, and show that the variant dosage dictates the severity of the motor neuron disease in SMAJ. We demonstrate that the amount of the mutant CHCHD10 is reduced, but the disease mechanism of p.G66V is not full haploinsufficiency as residual mutant CHCHD10 protein is present even in a homozygous state. Novel knock-in mouse model recapitulates the dose-dependent reduction of mutant CHCHD10 protein and the slow disease progression of SMAJ. With metabolome analysis of patients' primary fibroblasts and patient-specific motor neurons, we show that CHCHD10 p.G66V dysregulates energy metabolism, leading to altered redox balance and energy buffering by creatine metabolism.

Keywords:  ALS; CHCHD10; CHCHD2; Creatine; Metabolomics; Mitochondria

DOI:  https://doi.org/10.1186/s40478-025-02039-3
EMBO J. 2025 May 23.

Mechanistic insights into Bcs1-mediated mitochondrial membrane translocation of the folded Rieske protein.

Cristian Rosales-Hernandez, Matthias Thoms, Otto Berninghausen, Thomas Becker, Roland Beckmann.

  A functional mitochondrial respiratory chain requires coordinated and tightly regulated assembly of mitochondrial- and nuclear-encoded subunits. For bc1 complex (complex III) assembly, the iron-sulfur protein Rip1 must first be imported into the mitochondrial matrix to fold and acquire its 2Fe-2S cluster, then translocated and inserted into the inner mitochondrial membrane (IM). This translocation of folded Rip1 is accomplished by Bcs1, an unusual heptameric AAA ATPase that couples ATP hydrolysis to translocation. However, the molecular and mechanistic details of Bcs1-mediated Rip1 translocation have remained elusive. Here, we provide structural and biochemical evidence on how Bcs1 alternates between conformational states to translocate Rip1 across the IM. Using cryo-electron microscopy (cryo-EM), we identified substrate-bound pre-translocation and pre-release states, revealing how electrostatic interactions promote Rip1 binding to Bcs1. An ATP-induced conformational switch of the Bcs1 heptamer facilitates Rip1 translocation between two distinct aqueous vestibules-one exposed to the matrix, the other to the intermembrane space-in an airlock-like mechanism. This would minimize disruption of the IM permeability barrier, which could otherwise lead to proton leakage and compromised mitochondrial energy conversion.

Keywords:  Bcs1; Cryo-EM; Folded Protein Translocation; Mitochondria; Rieske

DOI:  https://doi.org/10.1038/s44318-025-00459-4
J Vis Exp. 2025 May 02.

Analysis of the Expression and Complexes Assembly of the Mitochondrial Respiratory Chain Proteins in the Fission Yeast Schizosaccharomyces pombe.

Guangchun Lu, Jinjie Shang, Gang Feng.

The mitochondrial respiratory chain is crucial for cellular energy metabolism, serving as the core of oxidative phosphorylation. The mitochondrial respiratory chain comprises five enzyme complexes and their interacting supercomplexes. Analysis of the expression and complexes assembly of these proteins is vital to understanding mitochondrial function. This can be studied by combining biochemical and genetic methods in an excellent model organism fission yeast Schizosaccharomyces pombe (S. pombe), which provides a compensatory system to budding yeast for studies of mitochondrial biology. Here, we present a detailed protocol for the isolation of S. pombe mitochondria and analysis of expression levels and complexes assembly of the mitochondrial respiratory proteins by SDS-polyacrylamide gel electrophoresis (SDS-PAGE) and blue native-PAGE (BN-PAGE). Briefly, mitochondria from the wild-type and gene mutants are purified, and then their complexes are solubilized and subjected to SDS-PAGE/BN-PAGE and immunoblotting. This method enables the characterization of a gene's novel function in the mitochondrial respiratory chain.

DOI: https://doi.org/10.3791/68336
Clin Neurophysiol. 2025 May 13. pii: S1388-2457(25)00590-5. [Epub ahead of print]175 2110738

Neuromagnetic responses to multimodal stimuli in Friedreich's ataxia.

Elisa Visani, Laura Canafoglia, Lorenzo Nanetti, Davide Rossi Sebastiano, Dunja Duran, Paola Anversa, Deborah Bonfoco, Sara Dotta, Davide Tabarelli, Anna Castaldo, Gloria Marchini, Alessia Mongelli, Caterina Mariotti.

   OBJECTIVE: This study explores the utility of various evoked fields in elucidating the pathophysiology of Friedreich's ataxia (FA) and potentially contributing to developing more targeted diagnostic and therapeutic strategies.
METHODS: Thirty-seven patients with FA aged 27.6 ± 7.4 years and a control group of 17 healthy subjects were enrolled in the study. The neuromagnetic response to auditory, tactile, visual, somatosensory, auditory and tactile oddball stimulation were acquired. For all the components of interest, latency and amplitude were measured and correlated with clinical data.
RESULTS: Neuromagnetic responses were identifiable in more than 90% of cases. A significant response delay was observed in all tested modalities (auditory, somatosensory, tactile and visual responses). P300 responses were comparable in patients and healthy subjects. Latencies of visual and auditory responses correlated with SARA scores. Moreover, latencies of auditory responses correlated with disease onset age, whereas latencies of visual responses correlated with disease severity.
CONCLUSIONS: Auditory and visual responses correlated with the severity of the disease, whereas alterations in somatosensory responses represent an intrinsic characteristic of the disease.
SIGNIFICANCE: In FA the study of evoked visual fields could provide a possible biomarker of disease progression and treatment efficacy.

Keywords:  Auditory; Friedreich’ ataxia; MEG; Multimodal evoked responses; Somatosensory; Visual

DOI:  https://doi.org/10.1016/j.clinph.2025.2110738
Metabolism. 2025 May 17. pii: S0026-0495(25)00169-6. [Epub ahead of print]170 156300

Overview of methods that determine mitochondrial function in human disease.

Eashan Sharma, Leila Fotooh Abadi, John Arnaud Kombe Kombe, Monisha Kandala, Jordan Parker, Nolan Winicki, Theodoros Kelesidis.

  Cellular metabolism has a key role in the pathogenesis of human disease. Mitochondria are the organelles that generate most of the energy needed for a cell to function and drive cellular metabolism. Understanding the link between metabolic and mitochondrial function can be challenging due to the variation in methods used to measure mitochondrial function and heterogeneity in mitochondria, cells, tissues, and end organs. Mitochondrial dysfunction can be determined at both the cellular and tissue levels using several methods, such as assessment of cellular bioenergetics, levels of mitochondrial DNA (mtDNA), mitochondrial membrane potential (MMP), mitochondrial reactive oxygen species (mito-ROS), and levels of mitochondrial enzymes. Recent advances involving novel radiotracers in combination with PET imaging have allowed for the determination of mitochondrial function in vivo with high specificity. Understanding the barriers in existing methodologies used to study mitochondrial function may help further establish the assessment of mitochondrial function as a biologically and clinically relevant biomarker for human disease severity and prognosis. Herein, we critically review the existing literature regarding the strengths and limitations of methods that determine mitochondrial function, and we subsequently discuss how emerging research methods have begun to overcome some of these hurdles. We conclude that a combination of techniques, including respirometry and mitochondrial membrane potential assessment, is necessary to understand the complexity and biological and clinical relevance of mitochondrial function in human disease.

Keywords:  Biomarkers; Human disease; Metabolism; Mitochondria; Mitrochondrial function

DOI:  https://doi.org/10.1016/j.metabol.2025.156300
Nat Commun. 2025 May 20. 16(1): 4695

Human mitochondrial ferritin exhibits highly unusual iron-O2 chemistry distinct from that of cytosolic ferritins.

Justin M Bradley, Zinnia Bugg, Jacob Pullin, Geoffrey R Moore, Dimitri A Svistunenko, Nick E Le Brun.

Ferritins are ubiquitous proteins that function in iron storage/detoxification by catalyzing the oxidation of Fe2+ ions and solubilizing the resulting Fe3+-oxo mineral. Mammalian tissues that are metabolically highly active contain, in addition to the widespread cytosolic ferritin, a ferritin that is localized to mitochondria. Mitochondrial ferritin (FtMt) protects against oxidative stress and is found at higher levels in diseases associated with abnormal iron accumulation, including Alzheimer's and Parkinson's. Here we demonstrate that, despite 80% sequence identity with cytosolic human H-chain ferritin, Fe2+ oxidation at the catalytic diiron ferroxidase center of FtMt proceeds via a distinct mechanism. This involves a mixed-valent ferroxidase center (MVFC) that is readily detected under the O2-limiting conditions typical of mitochondria, and formation of a radical on a strictly conserved Tyr residue (Tyr34) that is key for the activation of O2 and stability of the MVFC. The possible origin of the mechanistic differences exhibited by the highly-related human mitochondrial and cytosolic H-chain ferritins is explored.

DOI: https://doi.org/10.1038/s41467-025-59463-1
Cell Commun Signal. 2025 May 20. 23(1): 232

From powerhouse to modulator: regulating immune system responses through intracellular mitochondrial transfer.

Mostafa Changaei, Zahra Azimzadeh Tabrizi, Mozhdeh Karimi, Seyed Adnan Kashfi, Tina Koochaki Chahardeh, Seyed Mahmoud Hashemi, Sara Soudi.

  Mitochondria are traditionally known as the cells' powerhouses; however, their roles go far beyond energy suppliers. They are involved in intracellular signaling and thus play a crucial role in shaping cells' destiny and functionality, including immune cells. Mitochondria can be actively exchanged between immune and non-immune cells via mechanisms such as nanotubes and extracellular vesicles. The mitochondria transfer from immune cells to different cells is associated with physiological and pathological processes, including inflammatory disorders, cardiovascular diseases, diabetes, and cancer. On the other hand, mitochondrial transfer from mesenchymal stem cells, bone marrow-derived stem cells, and adipocytes to immune cells significantly affects their functions. Mitochondrial transfer can prevent exhaustion/senescence in immune cells through intracellular signaling pathways and metabolic reprogramming. Thus, it is emerging as a promising therapeutic strategy for immune system diseases, especially those involving inflammation and autoimmune components. Transferring healthy mitochondria into damaged or dysfunctional cells can restore mitochondrial function, which is crucial for cellular energy production, immune regulation, and inflammation control. Also, mitochondrial transfer may enhance the potential of current therapeutic immune cell-based therapies such as CAR-T cell therapy.

Keywords:  Immune system; Immunometabolism; Immunotherapy; Mitochondria; Mitochondria Transfer; Organelle therapy

DOI:  https://doi.org/10.1186/s12964-025-02237-5
Acta Physiol (Oxf). 2025 Jun;241(6): e70056

Mitochondrial Bioenergetics in Physiology.

Martin Jastroch, Michaela Keuper.



Keywords:  bioenergetics; brown adipose tissue; disease; ectothermic; endothermic; mitochondria; sarcopenia; ucp1

DOI:  https://doi.org/10.1111/apha.70056
Sci Rep. 2025 May 22. 15(1): 17734

Adaptation of mitochondrial bioenergetics to coenzyme Q deficiency in human endothelial cells after chronic exposure to bisphosphonates.

Adrianna Budzinska, Lukasz Galganski, Krzysztof Wojcicki, Wieslawa Jarmuszkiewicz.

  Nitrogen-containing bisphosphonates (N-BPs), widely used in bone disease therapy, inhibit the mevalonate pathway, which affects coenzyme Q (CoQ) biosynthesis and may compromise mitochondrial function, particularly in endothelial cells where oxidative stress and mitochondrial dysfunction contribute to cardiovascular disease. This study examined the effects of chronic six-day exposure of human endothelial cells to N-BPs on mitochondrial bioenergetic functions, focusing on drug-induced mitochondrial CoQ (mtCoQ) deficiency. Compared with the mitochondria of control cells, those of endothelial cells treated with 5 µM alendronate or 1 µM zoledronate presented a significant 45-50% decrease in total mtCoQ pool, loss of reduced (mtCoQH2) antioxidant mtCoQ pool, and elevated mitochondrial antioxidant protein superoxide dismutase 2 (SOD2) and uncoupling protein 2 (UCP2) levels. Exposing endothelial cells to N-BPs also led to an overall reduction in mitochondrial substrate oxidation, except for increased fatty acid oxidation. Additionally, the mitochondria of N-BP-treated endothelial cells presented decreased respiratory rates, membrane potential, and ATP synthesis efficiency, and increased H2O2 production resulting from increased mtCoQ reduction during the oxidation of complex I (CI) and CII substrates. N-BP-induced mtCoQ deficiency also resulted in rearranged respiratory chain supercomplexes, particularly downregulation of the III2 + IV supercomplex, and decreased CII, CIII, and CV protein levels and activities. Despite the N-BP-induced decrease in a-heme levels, maximal CIV activity remained unaffected in endothelial mitochondria. These findings highlight the role of N-BPs in disrupting mtCoQ redox homeostasis and associated bioenergetic functions in endothelial mitochondria.

Keywords:  Alendronate; Bisphosphonates; Coenzyme Q; Endothelial cells; Mitochondrial respiration; Zoledronate

DOI:  https://doi.org/10.1038/s41598-025-02710-8
Neuroscience. 2025 May 20. pii: S0306-4522(25)00371-9. [Epub ahead of print]577 228-239

Miro1: A potential target for treating neurological disorders.

Linghua Zeng, Juan Yang, Conghui Zhang, Junjie Zhu, Saichun Zhong, Xing Liu, Haiyu Xie, Lifeng Wang, Li Chen, Maolin Zhong, Fuzhou Hua, Weidong Liang.

  The Miro1 protein is a member of the mitochondrial Rho GTPase (Miro) protein family and plays a crucial role in regulating the dynamic processes of mitochondria and participating in cellular movement and mitochondrial transport. In the nervous system, it ensures adequate energy supply for normal neuronal function and synaptic transmission. Additionally, Miro1 actively participates in the regulation of mitochondrial quality control and stress responses within neurons. Its primary function is to sense intracellular stress signals to regulate mitochondrial movement and metabolism, thereby adapting to environmental changes. Multiple studies have indicated that the Miro1 protein is associated with the pathogenesis of various neurological disorders, such as Alzheimer's Disease(AD), Parkinson's Disease(PD), and Amyotrophic Lateral Sclerosis(ALS). This article reviews the mechanistic role of Miro1 in these diseases and summarizes the latest research on its involvement in neurological disorders. These efforts aim to provide unified treatment strategies for certain neurological disorders and explore the potential for treating complex neurological diseases.

Keywords:  AD; ALS; Miro1; Mitochondria; Neurological disorders; PD

DOI:  https://doi.org/10.1016/j.neuroscience.2025.05.019
Sci Rep. 2025 May 23. 15(1): 17955

M2 microglia-derived exosomes reduce neuronal ferroptosis via FUNDC1-mediated mitophagy by activating AMPK/ULK1 signaling.

Jian Li, Qing Chen, Hao Gu.

  Neuronal ferroptosis plays a vital role in the progression of neonatal hypoxic-ischemic brain damage (HIBD). M2-type microglia-derived exosomes (M2-exos) have been shown to protect neurons from ischemia-reperfusion (I/R) brain injury, but their impact on I/R-induced neuronal ferroptosis and the underlying mechanisms remain poorly understood. In this study, we used an in vitro oxygen-glucose deprivation/reoxygenation (OGD/R) model in HT-22 neuronal cells to investigate how M2-exos modulate ferroptosis. We found that M2-exos were internalized by HT-22 cells and significantly attenuated OGD/R-induced ferroptosis. Mechanistically, M2-exos enhanced mitophagy, which was mediated by the upregulation of FUN14 domain-containing protein 1 (FUNDC1), thereby inhibiting ferroptosis. Further analysis revealed that M2-exos activated FUNDC1-dependent mitophagy through the AMP-activated protein kinase (AMPK)/UNC-51-like kinase 1 (ULK1) signaling pathway. Taken together, these findings suggest that M2-exos ameliorate I/R-induced neuronal ferroptosis by enhancing FUNDC1-mediated mitophagy through the activation of AMPK/ULK1 signaling pathway.

Keywords:  Exosome; Ferroptosis; Ischemia/reperfusion; Microglia; Mitophagy

DOI:  https://doi.org/10.1038/s41598-025-03091-8
Nat Commun. 2025 May 19. 16(1): 4653

Optimized AAV capsids for basal ganglia diseases show robust potency and distribution.

D E Leib, Y H Chen, L Tecedor, P T Ranum, M S Keiser, B C Lewandowski, E M Carrell, S Arora, I Huerta-Ocampo, D Lai, C M Fluta, C Cheng, X Liu, B L Davidson.

Huntington's disease and other disorders of the basal ganglia create challenges for biomolecule-based medicines given the poor accessibility of these deep brain structures following intracerebral or intravascular delivery. Here, we found that low dose, low volume delivery of unbiased AAV libraries into the globus pallidus allowed recovery of novel capsids capable of broad access to key deep brain and cortical structures relevant for human therapies. One such capsid, AAV-DB-3, provided transduction of up to 45% of medium spiny neurons in the adult NHP striatum, along with substantial transduction of relevant deep layer neurons in the cortex. Notably, AAV-DB-3 behaved similarly in mice as in NHPs and potently transduced human neurons derived from induced pluripotent stem cells. Thus, AAV-DB-3 provides a unique AAV for network level brain gene therapies that translates up and down the evolutionary scale for preclinical studies and eventual clinical use.

DOI: https://doi.org/10.1038/s41467-025-60000-3
J Physiol. 2025 May 21.

Shaping the waves: Mitochondrial regulation of calcium oscillations in smooth muscle.

Harold A Coleman, Helena C Parkington.



Keywords:  IP3; calcium store; calcium wave; endoplasmic reticulum; intracellular calcium; mitochondria; smooth muscle; voltage‐dependent calcium channel

DOI:  https://doi.org/10.1113/JP288974
Cell. 2025 May 14. pii: S0092-8674(25)00461-1. [Epub ahead of print]

LoxCode in vivo barcoding reveals epiblast clonal fate bias to fetal organs.

Tom S Weber, Christine Biben, Denise C Miles, Stefan P Glaser, Sara Tomei, Cheng-Yu Lin, Andrew Kueh, Martin Pal, Stephen Zhang, Patrick P L Tam, Samir Taoudi, Shalin H Naik.

  Much remains to be learned about the clonal fate of mammalian epiblast cells. Here, we develop high-diversity Cre recombinase-driven LoxCode barcoding for in vivo clonal lineage tracing for bulk tissue and single-cell readout. Embryonic day (E) 5.5 pre-gastrulation embryos were barcoded in utero, and epiblast clones were assessed for their contribution to a wide range of tissues in E12.5 embryos. Some epiblast clones contributed broadly across germ layers, while many were biased toward either blood, ectoderm, mesenchyme, or limbs, across tissue compartments and body axes. Using a stochastic agent-based model of embryogenesis and LoxCode barcoding, we inferred and experimentally validated cell fate biases across tissues in line with shared and segregating differentiation trajectories. Single-cell readout revealed numerous instances of asymmetry in epiblast contribution, including left-versus-right and kidney-versus-gonad fate. LoxCode barcoding enables clonal fate analysis for the study of development and broader questions of clonality in murine biology.

Keywords:  Cre; barcoding; cell fate; clonal; embryogenesis; epiblast; lineage tracing; mathematical modeling; pedigree; phylogenetics

DOI:  https://doi.org/10.1016/j.cell.2025.04.026
Orphanet J Rare Dis. 2025 May 17. 20(1): 235

Endocrine manifestations and long-term outcomes of patients with mitochondrial diseases.

Ja Hye Kim, Dohyung Kim, Soojin Hwang, Gu-Hwan Kim, Beom Hee Lee, Han-Wook Yoo, Jin-Ho Choi.

   BACKGROUND: Endocrine dysfunctions are commonly associated with mitochondrial diseases. This study aimed to investigate clinical characteristics and outcomes of endocrine manifestations in patients with mitochondrial diseases.
METHODS: This study included 54 patients from 47 families with mitochondrial diseases who were genetically confirmed; 49 patients with mitochondrial encephalomyopathy, lactic acidosis, and stroke-like episodes (MELAS), four with Pearson syndrome, and one with Kearns-Sayre syndrome (KSS). Clinical and endocrine findings were retrospectively reviewed.
RESULTS: The median age at diagnosis was 18.5 years (range, 0.1 - 49 years). In 49 patients with MELAS, the mean height and weight standard deviation scores were - 2.0 ± 1.3 and - 2.6 ± 1.6, respectively, with 44.9% (n = 22) of the patients exhibiting short stature at diagnosis. Twenty-three (46.9%) patients with MELAS were diagnosed with diabetes mellitus (DM) at a median age of 26 years (range, 12 - 50 years). Interestingly, papillary thyroid cancer was observed in 10.2% of patients (n = 5) with MELAS at a mean age of 34.1 ± 6.9 years. One patient with MELAS and one with KSS exhibited hypoparathyroidism. Patients with Pearson syndrome and KSS exhibited more severe short stature. Adrenal insufficiency was noted in 50% of the patients with Pearson syndrome.
CONCLUSIONS: In 20% of patients with MELAS, endocrine dysfunctions including having a short stature, DM, and hypoparathyroidism preceded the onset of neurological manifestations. Papillary thyroid cancer occurred in 10% of patients with MELAS. Patients with Pearson syndrome and KSS showed profound growth retardation and multisystem dysfunctions, such as chronic kidney disease and neurological defects, which contributed to increased mortality.

Keywords:  Adrenal insufficiency; Diabetes mellitus; Hypoparathyroidism; Kearns–Sayre syndrome; Mitochondrial encephalomyopathy, lactic acidosis, stroke-like episodes; Pearson syndrome

DOI:  https://doi.org/10.1186/s13023-025-03773-6