bims-polgdi Biomed News
on POLG disease
Issue of 2026–01–04
thirty-one papers selected by
Luca Bolliger, lxBio



  1. Biology (Basel). 2025 Dec 02. pii: 1728. [Epub ahead of print]14(12):
      Mitochondria play essential roles for animal reproduction, influencing not only cellular energetics but also gamete quality, inheritance and evolutionary patterns. Currently, most research still focuses on chordates or mitochondrial diseases and their impact on the health of germ cells. However, few studies focus on integrative synthesis that connect comparative morphology, inheritance mechanisms and evolutionary theory. In this review, we integrate cross-phyla evidence to explore two interconnected dimensions: the fate of mitochondria during gametogenesis and the strategy shaping their evolution. We compare mitochondrial morphology, distribution, and metabolic strategies in gametogenesis, revealing how these traits align with reproductive modes and ecological adaptations. Then we further discuss how mitochondrial genome evolution, bottleneck effects and mito-nuclear coevolution contribute to germline stability and maternal inheritance. Special attention is given to exceptional systems such as Doubly Uniparental Inheritance (DUI) in bivalves, which challenges conventional mode of strictly maternal transmission and illuminates the flexibility of mito-nuclear evolution. Altogether, these perspectives highlight mitochondria as gatekeepers and evolutionary recorders in the reproductive systems across metazoans, providing a unifying framework for future research across ecology, evolution and molecular biology.
    Keywords:  Doubly Uniparental Inheritance (DUI); gametogenesis; mito-nuclear coevolution; mitochondria; mitochondria evolution
    DOI:  https://doi.org/10.3390/biology14121728
  2. Int J Mol Sci. 2025 Dec 13. pii: 12023. [Epub ahead of print]26(24):
      Mitochondrial tRNA genes are critical hotspots for pathogenic mutations and several mitochondrial diseases. They account for approximately 70-75% of disease-causing mtDNA variants despite comprising only 5-10% of the mitochondrial genome. These mutations interfere with mitochondrial translation and affect oxidative phosphorylation, resulting in remarkably heterogeneous multisystem disorders. Under this light, we systematically reviewed PubMed, Scopus, and MITOMAP databases through October 2025, indexing all clinically relevant pathogenic mt-tRNA mutations classified by affected organ systems and underlying molecular mechanisms. Approximately 500 distinct pathogenic variants were identified across all 22 mt-tRNA genes. Beyond typical syndromes like MELAS, MERRF, Leigh syndrome, and Kearns-Sayre syndrome that are linked to mt-tRNA mutations, they increasingly implicate cardiovascular diseases (cardiomyopathy, hypertension), neuromuscular disorders (myopathies, encephalopathies), sensory impairment (hearing loss, optic neuropathy), metabolic dysfunction (diabetes, polycystic ovary syndrome), renal disease, neuropsychiatric conditions, and cancer. Beyond sequence mutations, defects in post-transcriptional modification systems emerge as critical disease mechanisms affecting mt-tRNA function and stability. The mutations on tRNA genes described herein represent potential targets for emerging genome editing therapies, although several translational challenges remain. However, targeted correction of pathogenic mt-tRNA mutations holds transformative potential for precision intervention on mitochondrial diseases.
    Keywords:  human diseases; mitochondrial tRNA; mt-tRNA modifications; mtDNA mutations
    DOI:  https://doi.org/10.3390/ijms262412023
  3. J Genet Genomics. 2025 Dec 30. pii: S1673-8527(25)00351-0. [Epub ahead of print]
      Cardiovascular diseases remain the leading cause of mortality worldwide. Mitochondrion, a key cellular organelle, harbors its own mitochondrial DNA (mtDNA) fundamental to cellular energy production through oxidative phosphorylation (OXPHOS). Beyond its canonical bioenergetic function, mtDNA integrity, copy number, and genetic variation play critical roles in maintaining cardiovascular function. This review provides a comprehensive overview of the multifaceted contributions of mtDNA to cardiovascular health and disease. We summarize the structural features and core biological functions of mtDNA, as well as the regulatory mechanisms governing its replication, biogenesis, and turnover. Particular emphasis is focused on mtDNA abnormalities, including point mutations, large-scale deletions, copy number alterations, and epigenetic modifications, and how these disturbances drive key pathogenic processes such as oxidative stress, chronic inflammation, apoptosis, and cellular senescence within the cardiovascular system. Furthermore, we highlight accumulating evidence linking mtDNA dysregulation to major cardiovascular disorders, including heart failure, atherosclerosis, and hypertension. Finally, we discuss the emerging diagnostic potential of circulating cell-free mtDNA and related mtDNA-derived metrics as non-invasive biomarkers, and outline therapeutic strategies aimed at preserving mtDNA integrity, modulating mtDNA content, or applying gene-based interventions to mitigate cardiovascular pathology.
    Keywords:  Mitochondrial DNA; cardiovascular diseases; diagnosis and therapy; inflammation; mitochondrial dysfunction; oxidative stress
    DOI:  https://doi.org/10.1016/j.jgg.2025.12.009
  4. Int J Mol Sci. 2025 Dec 12. pii: 11984. [Epub ahead of print]26(24):
      As the central hub of retinal metabolism, mitochondria are vital for sustaining the integrity of the inner blood-retinal barrier (iBRB), which is fundamental to retinal homeostasis. Mitochondrial dysfunction accelerates severe iBRB disruption, a process which is increasingly implicated in a cascade of mitochondrial pathologies including mitochondrial DNA destabilization, oxidative stress, calcium homeostasis disruption, mitochondrial autophagy deficiency, and dysregulated dynamic regulation. This review establishes the iBRB as a crossroads for metabolic, redox, and inflammatory signaling. By analyzing evidence from diabetic retinopathy and retinal vein occlusion models, we clarify how mitochondrial decline translates local energy deficiency into chronic barrier dysfunction. We posit that restoring mitochondrial function is indispensable for vascular resilience and regeneration, a conclusion drawn from integrating molecular, cellular, and translational findings. To advance mitochondrial discoveries into clinical practice, subsequent studies must prioritize achieving spatiotemporally controlled, cell-type-specific interventions with robust in vivo efficacy, thereby successfully translating mitochondrial science into clinical vascular medicine.
    Keywords:  diabetic retinopathy; inner blood-retinal barrier; mitochondrial dysfunction; mitochondrial plasticity; mitochondrial therapy; mitophagy; oxidative stress; retinal vein occlusion
    DOI:  https://doi.org/10.3390/ijms262411984
  5. Orphanet J Rare Dis. 2025 Dec 31.
       INTRODUCTION: Rare genetic diseases are, collectively, not in fact rare. However, educational opportunities focused on rare genetic disease can be limited. The Internet has increased the availability of education related to rare genetic disease and is accessible to a diverse range of people who seek out such information, including healthcare professionals, researchers, students, patients, and the public.
    PURPOSE: To assess the potential educational outreach of the Internet, this systematic literature review will appraise the landscape of what education for rare genetic disease is available online, describing its form, subject, and intended audience.
    METHODS: This systematic review encompassed all results across 20 science, healthcare, and education databases published up to September 1, 2023. The search criteria were specific to online education for rare genetic diseases.
    RESULTS: From 1663 total results, after applying exclusion criteria, 58 publications remained, ranging from 2002 to 2023. Although the amount of research presenting rare genetic disease education online was limited, the forms of education and its target learners were varied. Studies could have multiple target learners and healthcare professionals (68.97% of papers) and healthcare consumers (62.07% of papers) represented the most common of 5 different learners. 22 different specific conditions or categories of disease were the focus of 56.90% papers, with the remainder being general subjects like 'genetic testing' or 'rare diseases' overall. Modes of delivery were mutually exclusive per paper, with websites (29.31% of papers) and web applications/modules (24.14% of papers) being the most common of 7 different forms. The highest representation for author institutions was the USA (58.62% of papers) out of 33 countries total. The broad spread of learners, subjects, and delivery forms demonstrates the potential for online education as a vehicle for advancing the reach of rare disease education.
    CONCLUSIONS: The greater accessibility afforded through online information creates an avenue for further availability of high-quality education on rare genetic diseases.
    Keywords:  Genetics; Healthcare; Online education; Open educational resources; Rare disease
    DOI:  https://doi.org/10.1186/s13023-025-03809-x
  6. J Cell Biol. 2026 Feb 02. pii: e202511183. [Epub ahead of print]225(2):
      In this issue, Xiong et al. (https://doi.org/10.1083/jcb.202503169) introduce mouse models that enable tissue-resolved mapping of peroxisome turnover and pexophagy across development, metabolism, and disease. This study reveals striking cell type-specific differences in peroxisome dynamics and establishes a versatile platform for dissecting how pexophagy integrates with mitochondrial quality control and whole-body metabolic homeostasis.
    DOI:  https://doi.org/10.1083/jcb.202511183
  7. Int J Mol Sci. 2025 Dec 08. pii: 11852. [Epub ahead of print]26(24):
      Mitochondrial dysfunction is a pivotal contributor to neurodegeneration. Neurons heavily rely on mitochondrial oxidative metabolism and therefore need highly efficient quality control mechanisms, including proteostasis, mitochondrial biogenesis, fusion-fission dynamics, and mitophagy, to sustain bioenergetics and synaptic function. With aging, deterioration of mitochondrial quality control pathways leads to impaired oxidative phosphorylation, excessive reactive oxygen species generation, calcium imbalance, and defective clearance of damaged organelles, ultimately compromising neuronal viability. Pathological protein aggregates, such as α-synuclein in Parkinson's disease, β-amyloid and tau in Alzheimer's disease, and misfolded superoxide dismutase 1 and transactive response DNA-binding protein 43 in amyotrophic lateral sclerosis, further aggravate mitochondrial stress, establishing self-perpetuating cycles of neurotoxicity. Such mitochondrial defects underscore mitochondria as a convergent pathogenic hub and a promising therapeutic target for neuroprotection. Intermediate filaments (IFs), traditionally viewed as passive structural elements, have recently gained attention for their roles in cytoplasmic organization, mitochondrial positioning, and energy regulation. Emerging evidence indicates that IF-mitochondria interactions critically influence organelle morphology and function in neurons. This review highlights the multifaceted involvement of mitochondrial dysfunction and IF dynamics in neurodegeneration, emphasizing their potential as targets for novel therapeutic strategies.
    Keywords:  axonal transport; cell architecture; cell quality; cytoskeleton; mitochondrial dynamics; mitochondrial quality; mitophagy; neurofilaments; neuron; reactive oxygen species
    DOI:  https://doi.org/10.3390/ijms262411852
  8. Biochimie. 2025 Dec 26. pii: S0300-9084(25)00316-5. [Epub ahead of print]242 97-107
      Exercise is widely recognized as an effective nonpharmacological therapy for noncommunicable diseases, with its health benefits mediated in part by exerkines. Recently, extracellular mitochondria (ex-Mito) have been suggested as a player in mediating intercellular communication. While it is known that the health benefits of exercise involve the remodeling of mitochondria in multiple organs, the impact of exercise on circulating ex-Mito is poorly understood. Most existing studies have focused on cell-free circulating mitochondrial DNA, skeletal muscle-derived extracellular vesicles, or platelet-derived mitochondria, without focusing on other types of ex-Mito. The cellular origin of exercise-induced circulating ex-Mito and the role of each form (vesicle-enclosed, free, or as mitochondrial components) in mediating exercise's therapeutic effects are yet to be elucidated. This review aims to delve into the role of ex-Mito as potential players in exercise-related health benefits, paving the way for future research aimed at uncovering the molecular culprits of this nonpharmacological therapy, including mitochondrial transfer and transplantation.
    Keywords:  Exercise training; Mitochondrial remodeling; Mitochondrial transfer; Mitochondrial transplantation; Nonpharmacological therapy
    DOI:  https://doi.org/10.1016/j.biochi.2025.12.011
  9. Genes (Basel). 2025 Dec 15. pii: 1497. [Epub ahead of print]16(12):
      Mitochondrial dysfunction is a defining hallmark of aging that connects redox imbalance, metabolic decline, and inflammatory signaling across organ systems. The mitochondrial deacetylase SIRT3 preserves oxidative metabolism and proteostasis, yet its age-related decline transforms metabolically demanding organs into sources of pro-senescent cues. This review synthesizes evidence showing how SIRT3 loss in select "driver tissues"-notably liver, adipose tissue, vascular endothelium, bone-marrow macrophages, and ovary-initiates systemic aging through the release of cytokines, oxidized metabolites, and extracellular vesicles. We discuss molecular routes and mediators of senescence propagation, including the senescence-associated secretory phenotype (SASP), mitochondrial-derived vesicles, and circulating mitochondrial DNA, as well as sex-specific modulation of SIRT3 by hormonal and intrinsic factors. By integrating multi-tissue and sex-dependent data, we outline a framework in which SIRT3 activity defines the mitochondrial threshold separating local adaptation from systemic aging spread. Targeting SIRT3 and its NAD+-dependent network may offer a unified strategy to restore mitochondrial quality, dampen chronic inflammation, and therefore recalibrate the aging dynamics of an organism.
    Keywords:  NAD+ metabolism; SIRT3; aging drivers; extracellular vesicles; inflammaging; mitochondrial acetylation; senescence; sex differences; systemic aging
    DOI:  https://doi.org/10.3390/genes16121497
  10. NeuroImmune Pharm Ther. 2025 Dec;4(4): 377-390
      Extracellular vesicles (EVs) are mediators of neurodegeneration and emerging therapeutic tools for central nervous system disorders. On the one hand, they help spread beta amyloid, tau, α-synuclein, TDP-43, and mutant SOD1, contributing to the signs and symptoms of Alzheimer's, Parkinson's, Amyotrophic lateral sclerosis, and Huntington's Diseases. By activating glial cells, they promote chronic neuroinflammation through carrying cytokines, inflammasomes, and chemokines. On the other hand, EVs' ability to transport neuroregulatory products and cross the blood-brain barrier makes them ideal vehicles for drug delivery. Their function can be surface-modified to deliver targeted therapies, including anti-inflammatory and neuroprotective regulatory RNAs, proteins, and lipids, as well as factors that help maintain neural homeostasis. Notably, we suggest that colostrum-derived EVs, enriched with growth factors and immune-regulatory microRNAs, offer a natural, scalable, and biocompatible source for neuroprotective treatment. Although EVs can act as "Janus-faced" entities - serving both as disease initiators and versatile therapeutic vehicles - controlling their activity can enable immune-based therapeutics for neurodegenerative diseases.
    Keywords:  colostrum; drug delivery; extracellular vesicles; microRNA; neurodegeneration; neuroinflammation
    DOI:  https://doi.org/10.1515/nipt-2025-0016
  11. Life (Basel). 2025 Dec 05. pii: 1863. [Epub ahead of print]15(12):
      Age-related changes are associated with mitochondrial dysfunction, which is often caused by the accumulation of mutations in mitochondrial DNA (mtDNA). One common model of aging and age-related diseases involves mice with a mutant DNA polymerase γ (PolGmut) whose proofreading function is impaired, which leads to the accumulation of mutations in mtDNA. The main limitation of such a model is that introducing a mutation into the mouse's own gene leads to the accumulation of mutations in mtDNA over several generations, making it impossible to rule out whether mtDNA mutations or compensatory effects are the cause of functional impairments such as accelerated aging. This paper describes two lines of transgenic animals with inducible expression of PolGmut. This inducible system prevents mutation accumulation in the germline, promoting stable reproduction and reproducibility of mice, increasing experimental flexibility for various studies of mitochondrial diseases. PolGmut activation at different stages of life and different tissues allows us to study the progression of pathological changes during mitochondrial aging over time and detect the onset of mutation accumulation. The simplicity, reproducibility, and temporal control of this system represent a significant methodological improvement for studying mitochondrial mutagenesis and the pathophysiology of aging. Using this model, we demonstrated that the most pronounced pathology in these animals is accelerated thymus involution and the accumulation of cytotoxic effector CD8+ T cells in the peripheral immune organs, while no significant abnormalities were observed in other organs and systems. These data probably indicate that mtDNA mutations primarily impair T-cell immune function.
    Keywords:  DNA polymerase γ; T lymphocytes; aging; immunity; mutator mice
    DOI:  https://doi.org/10.3390/life15121863
  12. bioRxiv. 2025 Dec 18. pii: 2025.12.17.694973. [Epub ahead of print]
      Mitochondrial ATP production is essential for life. Mitochondrial function depends on the spatio-temporal coordination of nuclear and mitochondrial genome expression, yet how this coordination occurs in highly polarized cells such as neurons remains poorly understood. Using high-resolution imaging in mouse peripheral sensory neurons and zebrafish larvae, we identified a sub-population of mitochondria enriched in mtDNA that are positioned at the collateral branch points of long sensory neurites, both in vitro and in vivo . While the mitochondria in neurites are generally depleted of mtDNA, those at axon branch points preferentially engage in mtDNA replication and transcription, accumulate nuclear-encoded mitochondrial mRNA, and are spatially linked to nascent cytosolic peptide synthesis. The mtDNA-positive mitochondrial pool exhibits asymmetric genome partitioning at division, shedding highly motile daughters that lack mtDNA. Asymmetric division rejuvenates the membrane potential of the mtDNA-rich, biogenesis-dedicated mitochondria. We also found that, in peripheral sensory neurons, axonal mitochondria rarely fuse or share matrix contents, explaining how differentiated daughters maintain their distinct composition and fate after fission. Thus, division-coupled mitochondrial self-renewal is yoked to neurite topology in sensory neurons, patterning mitochondrial diversity and homeostasis from micron to meter scales.
    DOI:  https://doi.org/10.64898/2025.12.17.694973
  13. Acta Naturae. 2025 Oct-Dec;17(4):17(4): 64-71
      Mitochondrial dysfunction is one of the pathogenetic mechanisms of neuronal damage during aging. The high energy dependence of neurons makes them particularly vulnerable to age-related changes accompanied by oxidative stress and impaired energy metabolism. The maintenance of a pool of functional mitochondria is regulated by mitophagy, which ensures the utilization of damaged organelles, thereby preventing the progression of mitochondrial dysfunction. Brain aging is accompanied by a reduced level of activity of metabolic processes, aggravated mitochondrial dysfunction, and an increased risk of developing neurodegenerative diseases such as Alzheimer's disease and Parkinson's disease. This review highlights the molecular and signaling pathways of mitophagy and its dysregulation during physiological and pathological aging, which is of particular interest for identifying pharmaceutical targets and developing potential therapies for neurodegenerative conditions.
    Keywords:  Alzheimer’s disease; Parkinson’s disease; aging; mitochondria; mitophagy
    DOI:  https://doi.org/10.32607/actanaturae.27674
  14. Front Mol Biosci. 2025 ;12 1712573
       Background & Aims: Wilson disease (WD) is a genetic disorder of copper metabolism caused by ATP7B mutations, leading to hepatic and systemic copper accumulation. While lysosomes are early storage sites, mitochondria appear highly vulnerable to copper toxicity. We performed a systematic review and meta-analysis to assess mitochondrial outcomes in WD patients and animal models.
    Methods: PubMed, Scopus, and SciFinder were searched through 11 September 2025, for studies reporting hepatic mitochondrial endpoints in WD (in patients and models using mice, rats, and dogs). Outcomes included mitochondrial copper, morphology, oxidative stress, mtDNA copy number, ATP production, and respiratory Complex activities. Random-effects meta-analyses were conducted.
    Results: Thirteen studies met the inclusion criteria. Mitochondrial copper was consistently elevated (standardized mean difference ±standard error: 6.7 ± 0.9, P < 0.001), with ultrastructural abnormalities (4 ± 2, P = 0.012). Oxidative stress markers increased (2.9 ± 0.9, P = 0.001), while MnSOD and aconitase declined with disease progression. mtDNA copy number was reduced (-0.7 ± 0.3, P = 0.032). ATP synthesis (-1.5 ± 0.6, P = 0.023) and Complex activities (-1.0 ± 0.3, P = 0.001) were impaired, especially in older or symptomatic subjects. Citrate synthase activity increased (2.8 ± 0.9, P = 0.003), consistent with compensatory biogenesis. Several abnormalities appeared in presymptomatic or young animals.
    Conclusion: Across human and animal studies, hepatic mitochondria in WD exhibit copper accumulation, structural injury, impaired bioenergetics, oxidative stress, and mitochondrial genome loss. Mitochondrial dysfunction arises early and worsens with progression, highlighting it as a central pathogenic feature and therapeutic target.
    Keywords:  MtDNA copy number; bioenergetics; citrate synthase; complex IV; copper toxicity; liver metabolism; oxidative stress; translational hepatology
    DOI:  https://doi.org/10.3389/fmolb.2025.1712573
  15. Orphanet J Rare Dis. 2025 Dec 29. 20(1): 628
       BACKGROUND: Drug development for rare diseases has hurdles against setting high priority because of the size of the market. Although many countries have incentive policies for the development of orphan drugs (drugs used against rare diseases), evaluation methods for determining the rare diseases warranting resource support have not yet been established. To promote research and development (R&D) of rare diseases and drug development, methods measuring the level of understanding of rare diseases and its comparison with that of other diseases are warranted. This study proposes a grading system for measuring simultaneously the level of understanding of rare diseases and progress in product development.
    METHODS: Using the Technology Readiness Levels (TRL) framework developed by the National Aeronautics and Space Administration, we proposed a Disease Readiness Level (DRL) to assess the understanding of rare diseases by comparing the characteristics of existing TRL derivatives in the medical field, adding a clinical guideline in the middle stage and extending the assessment period to earlier stages than product development. Case studies with the developed framework were conducted for four rare diseases.
    RESULTS: The DRL comprehensively described the four selected rare diseases, muscular dystrophy, progressive fibrodysplasia ossificans, Tangier disease, and idiopathic peripheral pulmonary artery stenosis from their disease origin in the pre-product development phase to the launch of therapeutic strategies over a longer period than previous TRL derivatives.
    CONCLUSIONS: This study developed a comprehensive framework for rare diseases that focuses on the disease rather than the product for assessment and covers information spanning disease discovery to drug development. The results of case studies using the framework suggest that DRL can analyze both the level of understanding of rare diseases and the progress of the product research and development (R&D), and can be used as a potential indicator for the allocation of R&D resources.
    Keywords:  Clinical guideline; Disease readiness levels; Disease understanding; Rare diseases; Regulatory readiness levels; Research and development; Research progress; Technology readiness levels
    DOI:  https://doi.org/10.1186/s13023-025-04135-y
  16. Aging Cell. 2026 Jan;25(1): e70353
      Aging is a heterogeneous process, with organ systems and individuals experiencing variable rates of decline that are not fully reflected by chronological age. This variability contributes to the complexity of system morbidity, which poses increasing challenges for clinical care and biomedical research. In this review, we discuss the heterogeneity of organ and whole-body aging and perspectives on genomics as possible mechanisms that relate to such heterogeneity. We discuss how static genomics, including nuclear genetic variants, and dynamic genetics, such as somatic mutations, epigenetic drifts, and mitochondrial DNA changes might explain the variable rate of aging across organ systems and the whole body. We discuss that the use of metrics that capture heterogeneity in organ and body aging is critical to identify genomic biomarkers of aging, clarifying mechanisms of adaptation versus decline.
    Keywords:  Health Octo Tool; epigenetics; genomics; heterogeneity of aging; organ aging
    DOI:  https://doi.org/10.1111/acel.70353
  17. Front Neurosci. 2025 ;19 1665272
      The endoplasmic reticulum (ER) and mitochondria are essential organelles that interact closely at specialized sites known as ER-mitochondria-associated membranes (MAMs). MAM is enriched with proteins from both the ER and mitochondria. ER stress sensors-inositol-requiring enzyme 1 (IRE1) and protein kinase RNA-like ER kinase (PERK) - are traditionally recognized for their roles in the unfolded protein response (UPR), which mitigates proteotoxic stress. However, recent studies reveal their non-canonical functions at MAMs, where they regulate calcium signaling, mitochondrial dynamics, and apoptosis through interactions with MAM-resident proteins. Disruption of these pathways is implicated in various diseases, particularly neurodegenerative disorders. This review highlights the emerging roles of IRE1 and PERK in preserving mitochondrial function and their relevance to neurodegeneration. It also examines pharmacological strategies targeting these proteins, which influence both UPR signaling and ER-mitochondrial communication, offering a comprehensive perspective on their roles in health and disease.
    Keywords:  ER stress sensors; ER-mitochondrial interactions; IRE1; UPR signaling; mitochondrial health; neurodegenerative diseases; pERK
    DOI:  https://doi.org/10.3389/fnins.2025.1665272
  18. J Environ Sci (China). 2026 Mar;pii: S1001-0742(25)00291-8. [Epub ahead of print]161 761-771
      Few repeated-measures studies with multiple time points have evaluated the sex-specific association between mitochondrial DNA copy number (mtDNAcn) and long-term exposure to metal mixtures. We conducted a repeated-measures study with three time points and 2550 observations in the manganese-exposed workers healthy cohort. Specifically, the blood concentrations of 15 metals and mtDNAcn were measured in 2012, 2017, and 2021. We employed a machine learning approach (GLMMLASSO) to select the metals most associated with mtDNAcn and used Bayesian kernel machine regression to examine their joint effects. In cross-sectional analyses (2550 visits), statistical methods consistently showed Calcium (Ca) was positively associated with mtDNAcn among overall visits (β = 0.292 in the linear mixed-effects model (LMM)) and dominated the positive overall effects of magnesium, Ca, titanium, iron, nickel, rubidium on mtDNAcn. An inverted "U"-shaped exposure-response curve between Ca and mtDNAcn appeared in males but not in females. Interaction analysis showed the association between Ca and mtDNAcn was significantly modified by gender. In repeated-measures analyses (807 visits), we explored the tendency for metals and mtDNAcn to change over three time points; the results confirmed the cross-sectional analyses. In overall visits, the positive association between Ca and mtDNAcn remained significant (β = 0.207 in LMM). For metal selection, Ca was identified as the predictor for mtDNAcn, and an inverted "U"-shaped exposure-response curve was found with mtDNAcn in males. Our findings reveal a consistent positive association between Ca and mtDNAcn with sex-dependent heterogeneity and suggest Ca may mitigate mitochondrial dysfunction induced by other metals.
    Keywords:  Calcium (Ca); Metal mixtures; Mitochondrial DNA copy number (mtDNAcn); Repeated-measures study; Sex-specific
    DOI:  https://doi.org/10.1016/j.jes.2025.05.022
  19. Mol Cell Biol. 2026 Jan 02. 1-19
      The brain is one of the most lipid-rich organs, reflecting the critical role of lipid metabolism in neuronal and glial cell function. While mitochondria are central to energy metabolism, calcium signaling, and cell death, they do not utilize lipid oxidation for energy but rely on lipids for membrane integrity and intracellular communication. Here we review the interactions between lipids and mitochondria in intracellular signaling within brain cells, examining their roles in normal physiology and the mechanisms underlying major neurodegenerative diseases. Alterations in lipid homeostasis and mitochondrial metabolism are implicated in neurodegeneration, highlighting the importance of lipid-mediated mitochondrial signaling pathways. Understanding these interactions provides insights into cellular dysfunction in neurodegenerative disorders and may inform future therapeutic strategies targeting lipid and mitochondrial pathways.
    Keywords:  Lipid signaling; calcium signaling; lipid peroxidation; mitochondria; neurodegeneration
    DOI:  https://doi.org/10.1080/10985549.2025.2607428
  20. ACS Chem Neurosci. 2025 Dec 27.
      Parkinson's disease (PD) is a chronic, progressive neurodegenerative disorder characterized by severe motor symptoms. While the degeneration of dopaminergic neurons in the substantia nigra plays a central role, other neurotransmitter systems also contribute to PD symptoms. α-Synuclein (αSyn), normally expressed in neurons to support synaptic function and neurotransmitter release, becomes pathologically accumulated in PD, despite not being upregulated under physiological conditions. Intracellular aggregation of αSyn into Lewy bodies is a hallmark of synucleinopathies. A vital facet of both the onset and progression of PD involves mitochondrial dysfunction, which links αSyn misimport into mitochondria with neuronal death. The interaction of αSyn with mitochondrial membranes has been identified, yet the complex stepwise biological mechanisms of αSyn misimport into the mitochondrial compartments, followed by its aggregation, culminating in mitochondria-mediated apoptosis, remain unknown. The Translocase of the Outer Mitochondrial Membrane (TOM) complex, vital for unidirectional import of >1300 mitochondrial proteins from the cytosol, can additionally misimport αSyn into mitochondria. This TOM-αSyn interplay can alter calcium homeostasis, reduce ATP biogenesis, elevate reactive oxygen species generation, and compromise mitochondrial dynamics, resulting in mitochondrial dysfunction and triggering cell death in dopaminergic neurons. Detailed analyses of TOM complex function, interactome, and TOM-αSyn association could lead to treatment approaches that restore mitochondrial homeostasis by mitigating the effects of αSyn pathology in neurodegenerative conditions. This review details the most recent findings on independent regulators of αSyn and the TOM complex and discusses TOM-αSyn interaction mechanisms and their outcomes on mitochondrial dynamics toward promoting development of therapeutics for neurodegeneration.
    Keywords:  Parkinson’s diseases; TOM complex; aggregation blockers; mitochondrial misimport; neurotoxic plaque; synuclein
    DOI:  https://doi.org/10.1021/acschemneuro.5c00323
  21. Biomedicines. 2025 Dec 09. pii: 3019. [Epub ahead of print]13(12):
      Background/Objectives: Cathepsins, lysosomal proteases crucial for neuronal proteostasis, mediate the clearance of misfolded and aggregated proteins. Their dysregulation is implicated in neurodegenerative and neuropsychiatric disorders such as Alzheimer's, Parkinson's, and Huntington's diseases. These conditions are characterized by toxic protein accumulation and impaired clearance, which exacerbate cellular stress responses, including the unfolded protein response (UPR), oxidative damage, and mitochondrial dysfunction. This review aims to summarize current knowledge on cathepsin roles in these pathways and assess their therapeutic potential. Methods: A comprehensive literature review was conducted, focusing on recent in vitro and in vivo studies investigating cathepsin function, inhibition, and modulation. Mechanistic insights and pharmacological approaches targeting cathepsins were analyzed, with attention to challenges in translating preclinical findings to clinical settings. Results: Cathepsins demonstrate a dual role: their proteolytic activity supports neuronal health by degrading toxic aggregates, but altered or insufficient activity may worsen proteotoxic stress. Studies reveal that cathepsins regulate autophagy, apoptosis, and neuroinflammation both intracellularly and extracellularly. Despite promising mechanistic data, clinical translation is hindered by issues such as poor inhibitor selectivity, limited brain penetration, and variability across preclinical models. Conclusions: Targeting cathepsins presents a promising strategy for treating neurodegenerative and neuropsychiatric disorders, but significant challenges remain. Future research should focus on improving drug specificity and delivery, and on developing standardized models to better predict clinical outcomes.
    Keywords:  ER stress; biochemical pathways; cathepsin inhibitors; cathepsins; drug development; mitochondrial disfunction; neurodegeneration; neurodegenerative disease
    DOI:  https://doi.org/10.3390/biomedicines13123019
  22. Front Endocrinol (Lausanne). 2025 ;16 1734527
      
    Keywords:  aging; cell death; inflammation; longevity; metabolism; mitochondrial stress; senescence
    DOI:  https://doi.org/10.3389/fendo.2025.1734527
  23. Molecules. 2025 Dec 10. pii: 4728. [Epub ahead of print]30(24):
      The pursuit of youth and longevity has accompanied human societies for millennia, evolving from mythological and esoteric traditions toward a scientific understanding of aging. Early concepts such as Greek ambrosia, Taoist elixirs, and medieval "aqua vitae" reflected symbolic or spiritual interpretations. A major conceptual transition occurred between the late nineteenth and early twentieth centuries, when aging began to be framed as a biological process. Pioneering ideas by Metchnikoff, together with early and sometimes controversial attempts such as Voronoff's grafting experiments, marked the first efforts to rationalize aging scientifically. In the mid-twentieth century, discoveries including the Hayflick limit, telomere biology, oxidative stress, and mitochondrial dysfunction established gerontology as an experimental discipline. Contemporary geroscience integrates these insights into a coherent framework linking cellular pathways to chronic disease risk. Central roles are played by nutrient-sensing networks such as mTOR, AMPK, and sirtuins, together with mitochondrial regulation, proteostasis, and cellular senescence. Interventions, including caloric restriction, fasting-mimicking diets, rapalogues, sirtuin activators, metformin, NAD+ boosters, senolytics, and antioxidant combinations such as GlyNAC, show consistent benefits across multiple model organisms, with early human trials reporting improvements in immune function, mitochondrial activity, and biomarkers of aging. Recent advances extend to epigenetic clocks, multi-omic profiling, gender-specific responses, and emerging regenerative and gene-based approaches. Overall, the evolution from historical elixirs to molecular geroscience highlights a shift toward targeting aging itself as a modifiable biological process and outlines a growing translational landscape aimed at extending healthspan and reducing age-related morbidity.
    Keywords:  anti-aging medicine; cellular senescence; geroscience; mTOR; metformin; nutrient-sensing pathways; senolytics; sirtuins
    DOI:  https://doi.org/10.3390/molecules30244728
  24. Aging Cell. 2026 Jan;25(1): e70335
      There is increasing evidence that nutrient composition, even without lowering total calorie intake, can shape lifespan through mechanisms independent of mitochondrial regulation. Brandon and colleagues recently reported that a low-protein, high-carbohydrate (LPHC) diet enriched with non-digestible cellulose, extends lifespan in mice by shifting the liver proteome through altered RNA splicing, a response different from the mitochondrial improvements typically seen with caloric restriction. The authors' findings support the "energy-splicing resilience axis," which proposes that changes in splicing help cells adapt to energetic and nutritional stress. We discuss how diet influences spliceosomal components such as SRSF1, linking nutrient sensing, AMPK signaling, and tissue-specific resilience pathways. We also consider the splicing paradox in aging, where beneficial isoforms increase despite a concomitant increase in splicing errors. Understanding how dietary and pharmacologic interventions modulate splicing may shed light on strategies to maintain homeostatic proteomes and support healthy longevity.
    DOI:  https://doi.org/10.1111/acel.70335
  25. Ther Adv Rare Dis. 2025 Jan-Dec;6:6 26330040251404519
       Background: Rare diseases (RDs) encompass over 6000-8000 conditions, with 94% lacking available therapies. These conditions affect 400 million people globally, including three million Canadians, who face numerous challenges throughout their healthcare journey. Patient engagement (PE) is increasingly recognized as essential for improving outcomes yet remains inadequate in RD and orphan drug research particularly in Canada, where a national strategy for integrating RD patients' perspectives is lacking. To address this gap, this paper presents a Rare Disease Patient Engagement Framework (RDPEF), a structured model designed to support meaningful PE across all levels of healthcare, including research.
    Objectives: To develop a RDPEF that addresses barriers to engagement, reduces stigma, and incorporates patient experience as a core element in RD and orphan drug research and decision-making.
    Design: A conceptual framework development study informed by qualitative research and a targeted review of existing PE frameworks.
    Methods: The RDPEF was developed using a systematic approach that combined a review of existing literature on PE frameworks with new qualitative research on the experiences of RD patients in Canada. Semi-structured interviews examined patients' healthcare journeys, focusing on disease management, access to orphan drugs, and opportunities for engagement. A thematic analysis of the existing literature and interview data identified common challenges, which guided the framework's design. The RDPEF integrates elements from various other PE models, customizes them to the specific needs of RD patients, and emphasizes engagement across the entire orphan drug lifecycle.
    Results: Thematic findings from qualitative research highlighted limited to no patient involvement beyond clinical trials, significant stigma and discrimination, and the absence of structured engagement in drug review and reimbursement processes. These insights informed the development of the RDPEF, which outlines levels and forms of engagement, guiding principles (including stigma reduction), and mechanisms for integrating patient experience across healthcare, policy, and research domains.
    Conclusion: The RDPEF is a timely tool for enhancing PE in orphan drug research. By addressing engagement barriers, reducing stigma, and centering patient experience, the framework offers a roadmap for patients, researchers, healthcare providers, and policymakers to create a more inclusive and responsive system for RD patients in Canada.
    Keywords:  access; framework; health stigma and discrimination; orphan drugs; patient engagement; patient engagement framework; patient experience; rare diseases; research
    DOI:  https://doi.org/10.1177/26330040251404519
  26. J Clin Endocrinol Metab. 2025 Dec 31. pii: dgaf698. [Epub ahead of print]
      Maternally Inherited Diabetes and Deafness (MIDD) syndrome is a rare form of monogenic diabetes most often caused by the pathogenic m.3243A>G mutation in the mitochondrial tRNALeu (UUR) gene, MT-TL1. Mutations causing MIDD are also associated with mitochondrial encephalomyopathy, lactic acidosis, and stroke-like episodes (MELAS). This paper analyzes the data of 15 probands with mitochondrial diabetes enrolled in the University of Chicago Monogenic Diabetes Registry all of whom have confirmed pathogenic variants, primarily m.3243A>G. Three of these probands (3/15) were selected for detailed case studies and pedigree analysis. Among the total cohort, sensorineural hearing loss (80%) and muscle weakness (53%) were frequent comorbidities, and all tested individuals were negative for islet autoantibodies. Treatment regimens included insulin and sulfonylureas, with some reporting use of biguanides despite safety concerns related to mitochondrial dysfunction. Three probands noted subjective improvement with mitochondrial cocktail supplementation. Familial heteroplasmy testing revealed significant inter- and intrafamilial variability. This cohort represents one of the largest clinically characterized U.S. populations with mitochondrial diabetes and underscores the importance of urine-based heteroplasmy testing and personalized management strategies informed by mitochondrial pathophysiology.
    Keywords:  Maternally Inherited Diabetes and Deafness (MIDD); Mitochondrial diabetes; and stroke-like episodes (MELAS); lactic acidosis; mitochondrial encephalomyopathy
    DOI:  https://doi.org/10.1210/clinem/dgaf698
  27. Neural Regen Res. 2025 Dec 30.
      Organoid technology, as an innovative approach, has shown great potential in disease modeling, target screening, and the development of treatment strategies. However, traditional organoids still have three major limitations in research: the absence of specific cell types, the lack of blood-brain barrier structure, and insufficient reproducibility of experimental results. In recent years, researchers have gradually overcome these limitations by introducing innovative techniques such as advanced culture methods, microfluidic systems, bioprinting, organoid transplantation, and assembloid construction. This progress has facilitated the widespread application of organoids in the study of neurodegenerative diseases. This paper aims to systematically review the technological innovations of organoids in the study of neurodegenerative diseases. By summarizing classical organoid construction strategies and their limitations, it emphasizes the value of organoids in comprehensive applications within neurodegenerative disease research. In this review, we focus on five specific neurodegenerative diseases: Alzheimer's disease, Parkinson's disease, Huntington's disease, amyotrophic lateral sclerosis, and frontotemporal dementia. Research in these diseases demonstrates that organoids improve experimental accessibility and reduce development cycles in disease modeling, target discovery, and therapeutic strategy formation. Using customized equipment and gene editing techniques, these organoids can be tailored to specific needs, providing pathophysiologically relevant disease models and enhancing our understanding of neurodegenerative diseases. Although organoid technology has demonstrated significant advantages in disease research, its potential for treating neurodegenerative diseases has not yet been fully explored, which may become an important direction for future research.
    Keywords:  Alzheimer disease; Huntington's disease; Parkinson's disease; amyotrophic lateral sclerosis; bioprinting; frontotemporal dementia; microfluidics; neurodegenerative diseases; organoids; transplantation
    DOI:  https://doi.org/10.4103/NRR.NRR-D-25-00924
  28. Biomedicines. 2025 Dec 11. pii: 3043. [Epub ahead of print]13(12):
      Background: Rare diseases (RDs) and neurodevelopmental disorders (NDDs) remain under-researched due to their low prevalence, leaving significant gaps in diagnostic strategies. Beyond next-generation sequencing, epigenetic profiling and particularly episignatures have emerged as a promising complementary diagnostic tool and for reclassifying variants of uncertain significance (VUS). However, clinical implementation remains limited, hindered by non-standardized methodologies and restricted data sharing that impede the development of sufficiently large datasets for robust episignature development. Methods: We conducted a systematic literature review following PRISMA 2020 guidelines to identify all studies reporting episignatures published between 2014 and 2025. The review summarizes methodological approaches used for episignature detection and implementation, as well as reports of epimutations. Results: A total of 108 studies met the inclusion criteria. All but three employed Illumina methylation arrays, mostly 450 K and EPIC versions for patient sample analysis. Three main methodological phases were identified: data quality control, episignature detection, and classification model training. Despite methodological variability across these stages, most studies demonstrated high predictive capabilities, often relying on methodologies developed by a small number of leading groups. Conclusions: Epigenetic screening has significant potential to improve diagnostic yield in RDs and NDDs. Continued methodological refinement and collaborative standardization efforts will be crucial for its successful integration into clinical practice. Nevertheless, key challenges persist, including the need for secure and ethical data-sharing frameworks, external validation, and methodological standardization.
    Keywords:  DMPs; DMRs; DNA methylation; VUS; episignatures; machine learning; neurodevelopmental disorders; rare disease
    DOI:  https://doi.org/10.3390/biomedicines13123043
  29. Pharmaceuticals (Basel). 2025 Dec 05. pii: 1859. [Epub ahead of print]18(12):
      The human sirtuins (SIRT1-SIRT7) are NAD+-dependent protein deacylases that orchestrate key cellular events such as metabolism, stress response, DNA repair, and aging. Accumulating evidence highlights their central role in women's health. This review integrates recent insights into the roles of sirtuins across the female lifespan and their involvement in reproductive, metabolic, oncologic, and age-related disorders. Sirtuins regulate reproductive function, pregnancy outcomes, and hormone-dependent cancers. Their decline with aging contributes to menopausal and metabolic complications. Pharmacological interventions that enhance sirtuin activity, such as NAD+ precursors and SIRT1 activators, show promise in mitigating these conditions. Collectively, understanding the isoform- and tissue-specific roles of sirtuins provides a foundation for developing therapeutics to improve the lifespan and healthspan of women.
    Keywords:  aging; estrogen; metabolic; sirtuin; women’s health
    DOI:  https://doi.org/10.3390/ph18121859
  30. Iran J Pharm Res. 2025 Jan-Dec;24(1):24(1): e168337
      
    Keywords:  Brain Death; Mitochondria; Mitochondrial Therapy; Mitotherapy
    DOI:  https://doi.org/10.5812/ijpr-168337
  31. Front Immunol. 2025 ;16 1714438
      Organ-specific autoimmune and rare inflammatory diseases present significant challenges for clinical trial design due to profound patient heterogeneity, small population sizes, and complex tissue-specific pathophysiology. To address these hurdles, this study proposes a conceptual Quantitative Systems Pharmacology (QSP) framework tailored to support end-to-end clinical trial design in this high-need area. The framework integrates multi-source data, including preclinical, omics, and real-world evidence, via Bayesian methods to inform prior distributions for model parameters. A core multiscale mechanistic model links intracellular signaling, cellular dynamics, and tissue-level pathology to simulate disease progression and drug effects. Virtual patient populations are generated by sampling from Bayesian posteriors, capturing real-world biological heterogeneity. These cohorts then undergo in silico clinical trial simulations to evaluate and optimize key design elements, such as dosing regimens, endpoint selection, patient stratification, and adaptive strategies, prior to real-world implementation. By providing a structured, disease-agnostic workflow, the framework enables rational decision-making for dose optimization, biomarker identification, and patient enrichment. It addresses critical bottlenecks in drug development for these complex diseases, offering a powerful tool to de-risk trials and improve the efficiency and success rate of clinical development programs.
    Keywords:  clinical trial simulation (CTS); mechanistic modeling; organ-specific autoimmune diseases; quantitative systems pharmacology (QSP); rare diseases
    DOI:  https://doi.org/10.3389/fimmu.2025.1714438