Search Results (576)

The clinical use of doxorubicin (DOX), an effective chemotherapeutic drug for breast cancer, is limited by off-target nephrotoxicity, which is exacerbated in elderly patients. While excessive mitochondrial fission is known to contribute to DOX-induced cardiotoxicity, its role in DOX-induced nephrotoxicity, particularly in the context of renal aging, remains unclear. To explore this and investigate the therapeutic potential of the mitochondrial fission inhibitor Mdivi-1, female Wistar rats with D-galactose-induced accelerated renal aging were allocated into four groups: vehicle, DOX, DOX+Mdivi-1 co-treatment, and DOX+Mdivi-1 post-treatment. DOX administration resulted in significant renal dysfunction, oxidative stress, inflammation, and histopathological damage. Mitochondrial dysfunction along with the increased expression of fission protein, decreased fusion proteins, and activation of apoptotic markers and PINK1 expression were also evident. Remarkably, both co-treatment and post-treatment with Mdivi-1 comparably and significantly attenuated DOX-induced renal damage. This study suggests that Mdivi-1 mitigates DOX-induced nephrotoxicity in the aged kidney by modulating mitochondrial dynamics, suppressing oxidative stress and inflammation, and inhibiting apoptosis. These findings highlight mitochondrial fission as a promising therapeutic target for the treatment of doxorubicin toxicity and provide further support for the possible use of Mdivi-1 as a therapeutic strategy to protect the kidneys of elderly breast cancer patients undergoing chemotherapy. Full article

Melatonin has evolved from its classical role as a pineal-derived circadian regulator to a molecule increasingly recognized for its mitochondrial and cytoprotective functions. This review examines the molecular mechanisms and translational implications of melatonin within a mitochondria-centered framework, with particular emphasis on reproductive medicine. Available evidence suggests that melatonin may influence mitochondrial quality control (MQC) through multiple interconnected processes, including ROS regulation, mitochondrial dynamics, mitophagy, biogenesis, and mitochondrial inflammatory signaling. In mitochondria, melatonin can attenuate electron transport chain-derived oxidative stress through direct radical-scavenging reactions, antioxidant metabolite formation, and indirect activation of endogenous antioxidant systems. Experimental studies further suggest that melatonin may modulate Drp1-mediated fission, OPA1- and Mfn1/2-associated fusion, PINK1/Parkin-mediated mitophagy, and SIRT1/PGC-1α-related mitochondrial biogenesis. In reproductive medicine, melatonin has been investigated as a potential adjunctive strategy in assisted reproductive technology, endometriosis, and polycystic ovary syndrome. However, clinical evidence remains heterogeneous, and most human studies have evaluated reproductive or biochemical outcomes rather than direct MQC-related biomarkers. Therefore, although melatonin represents a promising mitochondria-targeted adjunct, standardized dosing strategies, tissue-level pharmacodynamic assessment, and validated mitochondrial biomarkers are needed to determine whether these mechanisms translate into reproducible clinical benefit. Full article

The liver ranks among the peripheral organs exhibiting the most robust circadian rhythmicity, with glucose homeostasis, lipid metabolism, and bile acid turnover governed by tightly phased diurnal oscillations. Mitochondria execute these programs, their output coordinated with the hepatocyte circadian state. The mitochondrial network undergoes dynamic remodeling across the 24 h cycle, encompassing oscillatory changes in bioenergetics, fusion–fission balance, and quality control. This interplay is bidirectional: core clock components drive rhythmic remodeling via cyclin-dependent kinase 1/mitogen-activated protein kinase (CDK1/MAPK)-dependent phosphorylation of dynamin-related protein 1 (DRP1) and the NAD⁺–SIRT1/SIRT3 axis, while retrograde signals modulate clock amplitude and entrainment. Circadian disruption is associated with mitochondrial dysfunction implicated in MASLD onset and progression to MASH and HCC, though this evidence remains largely correlative and derives predominantly from rodent models. This review integrates clock–mitochondria coupling with metabolic liver disease. Restoring this coupling has been proposed as a candidate chronotherapeutic strategy, supported by preliminary rhythmicity data in primary human hepatocytes and a hepatocellular carcinoma cell line, though causal validation in healthy human liver is lacking. Time-restricted feeding, NAD⁺ precursors, PPAR agonists, and ACC inhibitors converge on clock-regulated pathways and may benefit from circadian-informed timing, though this remains unverified. Full article

The disruption of mitochondrial homeostasis is a trigger for insulin resistance. The loss of N-acetyltransferase 1 (Nat1) function, an insulin-sensitivity gene, contributes to mitochondrial dysfunction and insulin resistance. Carnosic acid (CA), a diterpene derived from rosemary, has demonstrated an anti-insulin-resistance effect. This study hypothesized that CA protects against TNF-α-induced insulin resistance in 3T3-L1 adipocytes by regulating mitochondrial dynamics, biogenesis, and function via Nat1. 3T3-L1 adipocytes were pretreated with CA for 12 h, followed by co-treatment with TNF-α for an additional indicated duration. Results showed that treatment of 3T3-L1 adipocytes with TNF-α decreases mitochondrial membrane potential (MMP) and PGC-1α protein levels and alters mitochondrial fission/fusion dynamics. Pretreatment with CA improved these effects. In parallel, CA prevented the TNF-α-induced reduction in Nat1 protein and improved insulin signaling by suppressing the phosphorylation of insulin receptor substrate-1 (IRS-1) at serine³⁰⁷, while restoring the phosphorylation of IRS-1 at tyrosine⁶²⁸ and Akt. Moreover, transfection with Nat1 siRNA inhibited the protective effect of CA against TNF-α-induced reductions in MMP, PGC-1α, and insulin signaling. In conclusion, CA ameliorated TNF-α-induced insulin resistance by reducing mitochondrial dysregulation by Nat1. Full article

Mitochondria play a central role in numerous physiological and pathological processes, and mitochondrial transplantation is emerging as a promising strategy to restore cellular function and mitigate disease. The success of this approach depends critically on the methods used to isolate, preserve, and retrieve intact, functional mitochondria. Objective: To optimize an isolation strategy that preserves mitochondrial integrity, dynamics, and metabolic activity and to evaluate conditions that enable short-term storage for future organelle biobanking applications. Methods: We compared a mitochondria isolation method developed in our laboratory (Protocol A) with a commercially available kit (Protocol B). Donor mitochondria were isolated from proximal tubular cells and transplanted into HEK293T recipient cells. Mitochondrial functionality was assessed following transfer into HEK293T cells by measuring reactive oxygen species (MitoSOX Red), oxygen consumption rate (OCR) using Seahorse XF analysis, and high-resolution imaging of mitochondrial morphology and dynamics. We further evaluated mitochondrial storage at low temperature and subsequent functional recovery. Results: Protocol A enabled faster isolation (~30 min) than Protocol B (~80 min) and yielded mitochondria with higher transplantation efficiency, greater OCR, preserved dynamic morphology, and lower oxidative stress. Mitochondria isolated using Protocol A remained metabolically active after transplantation and continued to exhibit fission and fusion, whereas those isolated using Protocol B showed reduced dynamic behavior. Importantly, mitochondria isolated with Protocol A retained functional integrity after low-temperature storage, supporting their potential for standardized preservation. Conclusions: This study presents a robust, efficient, and reproducible isolation and frozen-storage protocol that yields highly functional mitochondria suitable for transplantation. The ability to preserve mitochondrial function after storage further highlights the potential for developing organelle biobanks to support future research and therapeutic applications. Full article

Mitochondria are highly dynamic structures that undergo constant remodelling by the process of fission and fusion. Using simulation methods, we study the effects of neuron loss in humans due to the proliferation of deletion mutations. We implement two models of an organelle, namely, closed cristae (CC) and open mitochondrion (OM). With CC, mtDNA are confined to a crista unless mixed by the process of fission and fusion. Conversely, mtDNA can diffuse freely throughout the organelle in the OM model. We also implement selective mitophagy in the CC model. Higher rates of mixing mtDNA increase the rate of neuron loss, a prerequisite for cognitive decline and dementia. Selective mitophagy mitigates the effect of high rate mixing. However, this mitigation is all or nothing. Even at nominal rates of mitophagy compared to higher mixing rates, neuron loss is almost completely eliminated. The results of our model suggest that the role of fission and fusion, in removing defective mtDNA, may be inconsistent with observed patterns of ageing and dementia. The model serves as a hypothesis-generating tool to stimulate experimental re-evaluation of the role of fission and fusion. Full article

Fiber Bragg grating (FBG)-based sensors are increasingly used for temperature and strain monitoring in both fission and fusion facilities, whereas their long-term mechanical reliability under intense γ–neutron fields remains insufficiently understood. Although radiation-resistant FBGs and optical fibers have demonstrated tolerance to fast-neutron fluences approaching 10²⁰ n/cm², the post-irradiation behavior of complete sensor assemblies, including their metallic packaging and joining regions, has received much less attention. This work presents methodology and results of assessing the post-irradiation mechanical properties of packaged FBG-based temperature and strain sensors. The investigated sensors were based on Cu-coated FBGs embedded in 316L stainless-steel bodies and joined using STEMET-1101 brazing filler metal. The sensors were irradiated in the cores of the IVG.1M and WWR-K research reactors to fast-neutron fluences of 4.5 × 10¹⁷ and 1.8 × 10²⁰ n/cm², with absorbed γ-doses of 29.1 MGy and 2.3 GGy, respectively. After decay storage and hot-cell disassembly, tensile testing, microhardness measurements, and SEM–EDS analysis were performed. The results demonstrate that the investigated metal-packaged FBG sensor of this design retained mechanical integrity under high-fluence reactor irradiation. Full article

Mitochondrial alterations, including mitochondrial DNA (mtDNA) loss and defects in maintenance pathways, have been recognized as an important driver for toxic effects of environmental pollutants. Therefore, exposure to nano-sized particles (1–100 nm in diameter; a new source of environmental pollution) may also result in these mitochondrial impairments; however, controversial results have been reported. Available studies collected from three electronic databases through July 2025 were pooled for a comprehensive assessment. Meta-analysis of 19 in vitro studies (69 datasets) showed exposure to nano-sized particles significantly reduced mtDNA content [standardized mean difference = −1.08; p-value = 0.001). The expression levels of mtDNA-encoded (ND1, COX1,2, CYTB, ATP6), mitochondrial biogenesis (SIRT1, PGC-1α, TFAM) and fusion genes (MFN1, MFN2, OPA1) were found to be significantly down-regulated, while fission genes DRP1 and FIS1 were up-regulated following nano-sized particle exposure after meta-analysis of corresponding in vitro and in vivo studies. Accordingly, mtDNA depletion and expression disruption in mtDNA-encoded and maintenance genes may represent important contributors to nano-sized particle exposure-induced diseases. Full article

Background: Mitochondria are the primary organelles that regulate cellular bioenergetic metabolism and maintain homeostasis, providing essential structural support for optimal cell survival. Nonetheless, advancing age leads to cumulative damage to mitochondrial structure and functional integrity, which is a defining characteristic of biological aging and is closely linked to the emergence and progression of numerous age-related diseases, including neurodegenerative disorders, cardiovascular diseases, and metabolic disorders. Scope of review: This article offers a thorough summary and review of mitochondrial quality control (MQC), emphasizing numerous critical processes, including mitochondrial biosynthesis, dynamic remodeling (fusion and fission), and mitophagy. We thoroughly elucidate the molecular pathways that regulate MQC and demonstrate how age-related dysregulation precipitates cellular senescence, highlighting the transition from physiological maintenance to pathological malfunction, which ultimately culminates in cellular aging. Conclusions and implications: This study systematically elaborates the pathophysiological mechanisms in the field, comprehensively evaluates the clinical translational potential of targeting the MQC pathway, highlights the key objectives of “restoring mitochondrial plasticity and removing dysfunctional mitochondria”, and explores novel intervention strategies. The restoration of normal mitochondrial function in cells throughout aging is a very promising path for precision medicine therapeutics with great translational potential, according to recent state-of-the-art research. The development of novel therapeutic approaches to improve functional healthy mitochondria can effectively delay aging and reduce the rising global burden of age-related diseases. Full article

Sepsis is a life-threatening syndrome characterized by a dysregulated host response to infection and progressive organ dysfunction. Although early antimicrobial therapy, source control, hemodynamic resuscitation, and organ support remain the foundations of care, these approaches do not directly reverse the cellular mechanisms that connect systemic inflammation to multi-organ failure. Mitochondrial dysfunction has emerged as a central mechanism linking impaired oxygen utilization, oxidative and nitrosative stress, immune-cell metabolic reprogramming, inflammatory amplification, and organ injury. During sepsis, inflammatory mediators, nitric oxide, microcirculatory abnormalities, calcium dysregulation, and metabolic stress converge on mitochondria, impairing oxidative phosphorylation and promoting mitochondrial reactive oxygen species/reactive nitrogen species (ROS/RNS) generation. When mitochondrial quality-control programs, including fission, fusion, mitophagy, and mitochondrial biogenesis, fail to restore network integrity, damaged mitochondria accumulate and become persistent sources of oxidative stress and danger signals. Mitochondrial damage-associated molecular patterns, particularly mitochondrial DNA, oxidized mitochondrial DNA, cardiolipin, ATP, and N-formyl peptides, activate innate immune pathways such as TLR9-MyD88-NF-kappaB, the NLRP3 inflammasome, and cGAS-STING signaling. In parallel, mitochondrial metabolism shapes macrophage activation, neutrophil function, T-cell competence, pyruvate-lactate handling through the pyruvate dehydrogenase complex, and the transition between hyperinflammation and immunosuppression. Clinical translation remains challenging because sepsis is biologically heterogeneous and mitochondrial dysfunction is dynamic, tissue-specific, and influenced by disease stage. This review synthesizes current knowledge on mitochondrial dysfunction in sepsis, emphasizing oxidative and nitrosative stress, mitochondrial quality control, mitochondrial damage-associated molecular pattern (DAMP) signaling, immunometabolism, organ-specific injury, candidate biomarkers, clinical translational strategies for mitochondria-targeted therapy, and future approaches based on multi-omics and artificial intelligence-assisted patient stratification. We argue that future therapeutic development should move beyond nonspecific antioxidant supplementation toward time-sensitive, phenotype-informed, and biomarker-guided mitochondrial medicine. Full article

Background/Objectives: Obesity-associated non-alcoholic fatty liver disease (NAFLD) drives systemic metabolic stress and accelerates chronic kidney disease, yet the mechanistic links remain unclear. Mitochondrial dysfunction has emerged as a central mediator of obesity-induced organ injury. Here, we investigated renal mitochondrial remodeling in a rat model of obesity-associated NAFLD (Ob-NAFLD) and examined the effects of metformin. Methods: Female Zucker rats (obese fa/fa and lean Fa/Fa) were fed an AIN-93G diet for eight weeks, followed by 10 weeks of metformin treatment in designated groups. Kidney tissues were analyzed using biochemical assays, immunoblotting, blue native PAGE, in-gel activity assays, and histological evaluation. Results: In Ob-NAFLD rats, renal ATP levels were elevated despite reduced electron transport chain (ETC) Complex III and increased Complex V expression, reflecting compensatory ATP synthase hyperactivity uncoupled from efficient oxidative phosphorylation. Mitochondrial dynamics were disrupted such that inhibitory phosphorylation of DRP1 was reduced, promoting fission, and total OPA1 expression was decreased with a shift in short-to-long isoform balance, indicating impaired fusion and cristae remodeling. Notably, ATPase inhibitory factor 1 (IF1), a checkpoint that limits ATP synthase overdrive, remained stably expressed, suggesting an adaptive ceiling or failed protective control under chronic metabolic stress. Metformin partially alleviated bioenergetic stress by lowering ATP and modestly restoring Complex III, yet ETC imbalance and structural remodeling persisted, revealing the limitations of metabolic modulation alone. Conclusions: These findings position entrenched mitochondrial dysregulation as a mechanistic bridge linking obesity-driven liver disease to kidney injury. Therapeutic strategies combining metabolic interventions with targeted restoration of ETC coordination, mitochondrial dynamics, and regulatory checkpoints such as IF1 may be required to fully restore renal mitochondrial health and prevent the progression of metabolic kidney disease. Full article

Photobiomodulation (PBM) is a non-invasive therapeutic strategy that uses red and near-infrared (NIR) light in the 590–950 nm range to modulate the cellular and molecular pathways involved in retinal homeostasis. At the molecular level, PBM acts primarily through photon absorption by cytochrome c oxidase (CcO, complex IV of the mitochondrial electron transport chain), whose four metal centres—two copper (CuA and CuB) and two heme groups (heme a and heme a₃)—absorb light across approximately 600–1000 nm. Photon capture promotes photodissociation of inhibitory nitric oxide (NO) from the binuclear CuB–heme a₃ centre, accelerates electron transfer, restores the proton-motive force and increases ATP synthesis. These primary events trigger a coordinated molecular programme that includes (i) transient mitochondrial reactive oxygen species (ROS) bursts that activate the Nrf2/Keap1/ARE axis and upregulate phase II antioxidant enzymes (HO-1, NQO1, GCLC, SOD2, catalase, GPx); (ii) calcium- and cAMP-dependent secondary signalling that converges on PI3K/Akt, MAPK/ERK, AMPK and mTOR pathways; (iii) suppression of NF-κB-driven cytokine production (TNF-α, IL-1β, IL-6) and of NLRP3 inflammasome activation; (iv) downregulation of the HIF-1α/VEGF axis, particularly at 590 nm; (v) anti-apoptotic remodelling of the Bcl-2/Bax ratio with reduced cytochrome c release and caspase-3/9 activation; and (vi) PGC-1α/TFAM/NRF1-driven mitochondrial biogenesis, alongside restoration of fission/fusion homeostasis (Drp1, Mfn1/2, Opa1) and PINK1/Parkin-mediated mitophagy. Wavelength specificity has a defined molecular basis: 590 nm modulates VEGF signalling and RPE pump activity, 660 nm interacts with the CuB centre and enhances O₂ binding at CcO, and 850 nm is absorbed by CuA and supports electron entry into complex IV. A second molecular axis is the bidirectional crosstalk between PBM and the circadian system: mitochondrial respiration, ATP turnover and CcO activity oscillate over the 24 h cycle under the control of the BMAL1/CLOCK and PER/CRY core machinery, the NAD⁺/SIRT1–SIRT3 axis and REV-ERBα. Preliminary preclinical and human observations suggest that NIR-induced bioenergetic and functional gains may be coupled to this rhythm, with greater benefit reported when light is delivered in the morning window (≈08:00–11:00); this time dependence should be regarded as an emerging hypothesis rather than an established clinical principle. The clinical evidence is unevenly developed across indications. It is most robust for non-exudative age-related macular degeneration, where multiwavelength PBM (590/660/850 nm; Valeda Light Delivery System) has shown disease-modifying potential in randomized controlled trials (LIGHTSITE I–III and the LIGHTSITE IIIB extension), with sustained BCVA gains and reduced incidence of geographic atrophy over 24 months and beyond. Evidence for retinitis pigmentosa, central serous chorioretinopathy and, with red-light monotherapy, childhood myopia is at present limited to small or short-term studies and remains preliminary. This narrative review synthesizes the molecular machinery engaged by PBM, integrates clinical findings across retinal diseases and discusses how chronotherapeutic delivery of light, aligned with the molecular clock, may further optimize therapeutic efficacy. Full article

Age-related hyperphosphatemia is increasingly recognized as a contributing factor in sarcopenia. This work studies the metabolic effects of elevated phosphate on muscle. C2C12 cells were differentiated in the absence or presence of 10 mM β-glycerophosphate (BGP), an exogenous phosphate donor. In addition, quadriceps muscles from four experimental groups of male C57BL/6J mice were analyzed: young (5 months) and old (24 months) fed with standard diet; old mice fed with hypophosphatemic diet or supplemented with the phosphate binder Velphoro^®, for the last three months of life. Mice were stratified according to sarcopenia degree based on muscle mass, strength and physical performance. Protein levels were determined by immunoblotting and mRNA expression by RT-qPCR. ATP levels were measured by luminescence and L-lactate production, citrate synthase and cytochrome c oxidase activities by colorimetric assays. Mitochondrial content, membrane potential and reactive oxygen species (ROS) were determined by fluorescence assay. BGP-treated cells showed increased glucose transporter 1 (GLUT1) and decreased NADH Dehydrogenase (CI-NDUFB8) protein expression, elevated hexokinase II (HK2), phosphoglycerate kinase 1 (PGK1) and lactate dehydrogenase A (LDHA) mRNA levels, reduced ATP levels, increased lactate production, and decreased mitochondrial enzyme activities. Moreover, BGP increased ROS, diminished mitochondrial membrane potential, and altered fusion–fission dynamics and mitophagy. In aged quadriceps, oxidative phosphorylation (OXPHOS) subunits and superoxide dismutase 2 (SOD2) expression were reduced. The hypophosphatemic diet improved all parameters, whereas Velphoro^® selectively increased Mitochondrial cytochrome C oxidase subunit 1 (CIV-MTCO1) expression. Several altered mitochondrial markers are associated with sarcopenia degree. Altogether, hyperphosphatemia induces metabolic changes that scale with the sarcopenic degree. Our findings show a relevant association between hyperphosphatemia and mitochondrial dysfunction, and they support the potential benefit of phosphate reduction as a strategy to prevent or mitigate sarcopenia. Full article

B cell activation requires the formation of an immune synapse (IS), where coordinated cytoskeletal remodeling and organelle dynamics enable antigen extraction and presentation. While mitochondria are known to regulate cellular metabolism during activation, their role in IS function remains poorly understood. Here, we investigated how mitochondrial dynamics influence antigen processing and presentation in B cells. We show that B cell receptor (BCR) engagement induces rapid phosphorylation of the mitochondrial fission GTPase Drp1 at Ser616. Treatment with mdivi-1, a compound used to perturb Drp1-associated mitochondrial fission that can also affect mitochondrial complex I activity, altered mitochondrial morphology, reduced mitochondrial activity, and decreased their stable accumulation at the synapse. This was accompanied by increased tubulin acetylation, lysosome retention near the MTOC, and reduced delivery to the synaptic membrane. Accordingly, lysosome fusion, antigen extraction, and presentation to T cells were significantly diminished in mdivi-1-treated B cells. Together, our findings suggest that mdivi-1-sensitive mitochondrial fission and activity are associated with mitochondrial positioning, lysosomal trafficking, and exocytosis at the B cell immune synapse, supporting a model in which mitochondrial dynamics contribute to efficient antigen extraction and presentation. Full article

Mitochondrial dysfunction has been increasingly implicated in the pathobiology of neurodevelopmental conditions, particularly autism and attention-deficit/hyperactivity disorder (ADHD). Because the developing brain is critically dependent on sustained ATP production, impairments in oxidative phosphorylation, mitochondrial dynamics, and redox balance may disrupt neuronal maturation, synaptic development, and neural circuit refinement during sensitive developmental periods. This review examines evidence from postmortem neurochemistry, genomics, magnetic resonance spectroscopy, and biomarker research to characterize mitochondrial impairment across autism and ADHD. Studies in autism report an elevated burden of heteroplasmic mitochondrial DNA (mtDNA) variants, along with alterations in mtDNA copy number, respiratory chain capacity, fission–fusion dynamics, and antioxidant defenses. Postmortem data demonstrate reduced activity of electron transport chain Complexes I, III, and V in the frontal cortex, temporal lobe, and cerebellum. These bioenergetic abnormalities are accompanied by elevated oxidative stress markers alongside mitochondria-mediated immune activation. In vivo neuroimaging corroborates these findings through elevated cerebral lactate and reduced phosphocreatine-to-ATP ratios. Evidence in ADHD is limited, but similarly implicates mitochondrial dysfunction, consistent with the frequent co-occurrence of these conditions and their partially shared architecture. The available literature supports mitochondrial dysfunction as a transdiagnostic biological feature of neurodevelopmental conditions, with relevance to mechanistic biomarker identification and targeted therapeutic development. Full article