Search Results (253)

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

Global plastic production has led to widespread contamination by micro- and nanoplastics, with polystyrene nanoplastics (PSNPs) increasingly being detected in human biological samples, including blood and cardiac tissue. Given the critical role of mitochondria in cardiac energy metabolism, this study investigated whether 100 nm PSNPs interact with mitochondria and affect mitochondrial function in H9c2 cardiomyoblasts. Cellular uptake and intracellular distribution were examined, followed by an evaluation of mitochondrial ultrastructure, intracellular and mitochondrial reactive oxygen species (ROS) production, mitochondrial membrane potential, mitochondrial dynamics and mitophagy-related gene expression, mitochondrial DNA copy number, and metabolic function. PSNPs were internalized but did not directly localize to mitochondria within 24 h. No significant cytotoxicity, increase in intracellular or mitochondrial ROS production, or alteration in basal metabolic activity was observed. However, PSNP exposure resulted in intracellular accumulation, an altered mitochondrial ultrastructure characterized by crista loosening and vacuole-like structural changes. These changes were accompanied by reduced mitochondrial membrane potential; the upregulation of mitochondrial dynamics-related genes, including optic atrophy 1 (Opa1) and dynamin-related protein 1 (Drp1); the suppression of PTEN-induced kinase 1 (PINK1)/Parkin RBR E3 ubiquitin protein ligase (Parkin)-mediated mitophagy-related genes; and decreased maximal respiratory capacity. Lactate production and the extracellular acidification rate remained unchanged, suggesting that compensatory glycolysis was not activated. These findings indicate that PSNP exposure induces early mitochondrial structural and functional alterations without substantial cell damage, suggesting a potential reduction in cardiac adaptive capacity under PSNP-induced stress conditions. Full article

Reparative macrophage polarization and macrophage-derived reactive oxygen species (ROS) are required for ischemia-induced revascularization in peripheral artery disease (PAD). Our previous study showed that mitochondrial fission protein dynamin-related protein 1 (DRP1) promotes reparative polarization and metabolic reprogramming in macrophages and post-ischemic neovascularization. However, the redox-dependent mechanism governing DRP1 activation in this context remains elusive. Here, using a mouse hindlimb ischemia (HLI) model of PAD, we identify cysteine sulfenylation (CysOH) of DRP1 as a critical redox modification induced in ischemic bone marrow (BM)-derived cells. BM chimeric mice reconstituted with CRISPR/Cas9-generated “redox-dead” DRP1-C631A knock-in mutant (Drp1^C/A) BM exhibited markedly reduced limb perfusion recovery and CD31⁺ capillary density in ischemic muscles following HLI. These defects were associated with enhanced Ly6G⁺ neutrophil accumulation, pro-inflammatory F4/80⁺CD80⁺ M1-like macrophages and reduced anti-inflammatory F4/80⁺CD206⁺ M2-like macrophages in ischemic muscle. Mechanistically, using an in vitro PAD model, hypoxia serum starvation (HSS) rapidly induced NADPH oxidase 2-dependent cytosolic ROS production and DRP1-CysOH formation in wild-type macrophages. In contrast, Drp1^C/A macrophages failed to undergo DRP1-CysOH-dependent mitochondrial fission under HSS, resulting in aberrant metabolic reprogramming characterized by enhanced glycolysis and mitochondrial ROS, pro-inflammatory p-NF-κB and M1-genes, and suppressed anti-inflammatory p-AMPK, efferocytosis and M2-genes. Thus, our findings establish DRP1 sulfenylation as a previously unrecognized redox-sensing mechanism that links ischemia-induced ROS to reparative macrophage reprogramming and revascularization, identifying a novel therapeutic target for PAD. Full article

Dynamin-related protein 1 (Drp1) is essential for mitochondrial dynamics in skeletal muscle, particularly in regulating fission, mitophagy, and maintaining mitochondrial function. Exercise is crucial for sustaining muscle function, promoting mitochondrial adaptations that enhance energy metabolism and oxidative capacity in skeletal muscle. In this Review, we discuss the role of Drp1 in exercise-induced mitochondrial adaptations and its potential implications for skeletal muscle health. We first address the evidence that Drp1 activity must be maintained within a narrow physiological range. Both Drp1 deficiency and overabundance provoke muscle atrophy and dysfunction, establishing a Goldilocks principle for mitochondrial fission. We then examine the multi-layered post-translational modification code that governs Drp1 activity, including canonical phosphorylation, redox-sensing modifications, and the receptor selectivity model that may specify distinct fission programs. A three-stage model of exercise-induced mitochondrial adaptation is presented, describing how Drp1 activity is temporally orchestrated from acute fragmentation through short-term remodeling to long-term network optimization, and how these morphological transitions govern substrate metabolism and determine exercise performance. The pathological consequences of Drp1 dysregulation are examined in metabolic disease, where Drp1 is chronically hyperactivated, and in aging, where Drp1 activity is deficient. Finally, we analyze the ROS-Drp1 signaling axis as the mechanistic basis for the bidirectional regulation of Drp1 by exercise. Moderate exercise-induced ROS production activates Nrf2 and AMPK signaling, which suppress excessive fission in metabolic disease while restoring insufficient fission in aging, thereby moving Drp1 activity toward the physiological Goldilocks zone in both contexts. This context-dependent, bidirectional regulation distinguishes exercise from pharmacological inhibitors and identifies the ROS-Drp1 axis as a therapeutic target for conditions at opposite ends of the Drp1 activity continuum, such as sarcopenia and type 2 diabetes. Full article

Early-life nutrition is critical for the development and health of dairy calves, necessitating alternatives to in-feed antibiotics. This study investigated whether dietary glycerol monolaurate (GML) enhances growth performance, reduces diarrhea incidence, improves systemic antioxidant and immune status, and modulates hepatic immunometabolic function in calves. Twenty-four Holstein bull calves (7 ± 0.5 d of age) were randomly assigned by body weight and age to a control group or a GML-supplemented group, both fed milk replacer with starter feed provided throughout the 45-day trial. Calves in the GML group received GML at a dosage of 100 mg/kg of body weight, mixed into the milk replacer prior to feeding. Calves in the GML group had significantly greater final body weight, average daily gain, and starter intake during the latter period (d 23–45) compared with the control group. GML supplementation also significantly reduced the incidence of diarrhea and fever, alongside lower fecal scores and fewer antibiotic treatments. Plasma analysis revealed enhanced antioxidant capacity, as indicated by increased total antioxidant capacity and glutathione peroxidase, along with an improved immune profile characterized by elevated immunoglobulin G and reduced interleukin-2. Transcriptomic analysis of the liver showed that GML upregulated genes and pathways related to innate antiviral immunity, such as radical S-adenosyl methionine domain containing 2, interferon-stimulated gene 15, and MX dynamin like GTPase 1. Lipidomics further indicated that GML induced a targeted remodeling of hepatic lipids, including increased diacylglycerols and triacylglycerols and decreased specific phospholipids and sphingolipids, suggesting a metabolic shift supportive of immune activation and inflammatory control. In conclusion, dietary GML enhances growth and health in suckling calves, which is mediated through a coordinated immunometabolic reprogramming in the liver. GML represents a promising functional fat additive for sustainable calf rearing. Full article

Although evolutionarily distant, the bacteria Listeria monocytogenes, Shigella flexneri, and Burkholderia thailandensis each undergo a “cell-to-cell” spreading process that allows these pathogens to disseminate within human tissues. Spread initiates when bacteria polymerize actin filaments that propel them through the host cell cytosol. The pathogens then remodel the plasma membrane into protrusions that are internalized by adjacent cells and resolved into double membranous vacuoles (DMVs) which lyse to liberate bacteria. In this review, we discuss recent publications indicating that L. monocytogenes, S. flexneri, and B. thailandensis each enhance their spread by altering the subcellular localization of human Dynamin 2—a GTPase that regulates endocytosis and other trafficking pathways. Interestingly, Dynamin 2 controls distinct steps in spread of L. monocytogenes, S. flexneri, and B. thailandensis. In the case of L. monocytogenes, the GTPase has the potential to restrict protrusion formation by generating tension at tight junctions. However, L. monocytogenes secretes a protein that relieves this restriction of protrusions, allowing efficient spread. During dissemination of S. flexneri and B. thailandensis, Dynamin 2 is co-opted to resolve protrusions into DMVs. B. thailandensis also mobilizes Dynamin 2 to lyse DMVs. These findings highlight diverse ways in which bacteria control Dynamin 2 to augment spread. Full article

Centronuclear myopathy (CNM) is a genetically heterogenous congenital myopathy traditionally classified as a membrane remodeling disorder. Emerging evidence reveals that centronuclear myopathy mutations converge upon common cellular dysfunction extending beyond membrane trafficking. This review proposes a unified model positioning CNM as a disorder of impaired organelle communication and structural crosstalk. We focus on how mutations in Myotubularin1 (MTM1) and gain-of-function mutations in Dynamin 2 (DNM2) disrupt the triad architecture, leading to aberrant calcium handling, mitochondrial dysfunction, imbalanced reactive oxygen species (ROS) production, and defective autophagy. These dysfunctions are not isolated but form a pathological feedback loop that compromises muscle integrity and regeneration. By identifying shared mechanisms across CNM types, this review positions the disorder as the convergence of organelle stress and cytoskeletal network failure. This perspective reveals novel therapeutic strategies based on the principle that targeting a central pathological node may alleviate systemic dysfunction. However, given the complexity of the organelle feedback loop, a comprehensive, multi-target approach may ultimately be required to achieve full phenotypic rescue across all affected tissues. Full article

The differentiation of dental papilla cells (DPCs) into functional odontoblasts is critical for dentinogenesis, yet the role of mitochondrial dynamics remains unclear. Here, we investigated the functional role of mitochondrial fission and mitochondria-associated endoplasmic reticulum membranes (MAMs) in the odontogenic differentiation of DPCs. Using in vitro differentiation models combined with confocal microscopy, transmission electron microscopy, and gain- and loss-of-function approaches, we found that odontogenic induction triggered early mitochondrial fragmentation and increased MAM formation. Dynamin-related protein 1 (DRP1) mediated mitochondrial fission, which in turn regulated MAM architecture and promoted differentiation. Malic enzyme 2 (ME2) acted as an upstream regulator, facilitating DRP1 recruitment and organizing MAM integrity. Notably, disruption of the ME2-DRP1-MAM axis impaired dentin formation both in vitro and in vivo, either by ME2 knockdown or pharmacological inhibition of DRP1 (Mdivi-1). These findings establish the ME2-DRP1-MAM axis as a critical metabolic–organellar switch driving odontoblast differentiation, providing new mechanistic insights into dentinogenesis and identifying potential therapeutic targets for dentin–pulp complex regeneration. Full article

Myostatin is associated with inflammatory processes; however, its renal expression and impact on mitochondrial homeostasis during chronic kidney disease (CKD) remain poorly defined. This study investigated whether omega-3 fatty acids (FAs) modulate renal myostatin and mitochondrial integrity under uremic conditions using both in vivo and in vitro models. In rats with adenine-induced CKD, omega-3 FA supplementation attenuated the increase in renal myostatin expression. Uremia was associated with impaired mitochondrial homeostasis, evidenced by decreased peroxisome proliferator-activated receptor gamma coactivator-1 alpha levels and increased dynamin-related protein 1 levels, alongside the upregulation of mitophagy and inflammatory markers. Furthermore, mitochondrial structural damage and reduced mitochondrial DNA (mtDNA) content were observed in uremic kidneys. Omega-3 FA treatment partially reversed these alterations, restored mtDNA levels, and preserved mitochondrial cristae integrity. In vitro, HK-2 cells treated with indoxyl sulfate exhibited increases in myostatin expression and mitochondrial impairment, which were mitigated by eicosapentaenoic acid, docosahexaenoic acid, or their combination. These findings suggest that omega-3 FAs exert protective effects against uremia-induced renal injury by suppressing myostatin and preserving mitochondrial homeostasis, specifically by modulating biogenesis, dynamics, and structural integrity. Consequently, omega-3 FAs may serve as a potential therapeutic strategy with which to preserve mitochondrial homeostasis in patients with CKD. Full article

Inflammatory bowel disease (IBD) is characterized by chronic intestinal inflammation, epithelial barrier disruption and immune dysfunction. Alleviating and curing these pathological manifestations is the goal of IBD treatment. Despite substantial advances in targeted immunotherapies and anti-inflammatory strategies, achieving sustained intestinal mucosal healing remains a major clinical challenge. Dynamin-related protein 1 (Drp1) is a GTPase that mediates mitochondrial fission and plays a crucial role in maintaining the dynamic balance of mitochondrial morphology and function. In IBD, Drp1 expression is frequently upregulated and continuously activated, resulting in excessive fission and fragmentation of mitochondria. This mitochondrial dysregulation contributes to ATP depletion and excessive reactive oxygen species (ROS) production, thereby exacerbating disease progression and amplifying inflammatory signaling. This review highlights the distinctive role of Drp1 as an integrative node in IBD. Specifically, we connect mitochondrial dynamics with epithelial barrier failure, immune dysregulation, inflammatory cell death, and intestinal microenvironment remodeling. We further emphasize the potential relevance of Drp1 for biomarker-based patient stratification and mechanism-informed therapeutic targeting, thereby distinguishing this review from more descriptive accounts of mitochondrial dysfunction in intestinal inflammation. Full article

Background/Objectives: Mitochondria are dynamic organelles that continuously undergo balanced cycles of fusion and division to maintain optimal function. Mitochondrial division is mediated by Dynamin-Related Protein 1 (DRP1), a cytosolic large GTPase whose phosphorylation at serine 616 (DRP1-S616Ⓟ) promotes its translocation to the outer mitochondrial membrane and organelle division. Dysregulated mitochondrial division disrupts cellular homeostasis and contributes to disease pathogenesis, including cancer. Our prior work demonstrated that the oncogene-induced mitogen-activated protein kinase (MAPK) pathway constitutively phosphorylates DRP1 at serine 616, which is essential to cellular transformation and correlates with oncogene status in patient tissues. Similarly, DRP1-S616Ⓟ is subject to pharmacologic control by targeted therapies against oncogenic MAPK signaling. Methods: Building upon this foundation, we developed and characterized a recombinant murine monoclonal antibody (referred to as 3G11) with high specificity for human DRP1-S616Ⓟ, raised against a peptide derived from the human DRP1 sequence. Results: Using diverse experimental platforms, we demonstrate the robust utility of 3G11 to detect DRP1-S616Ⓟ in melanoma cell extracts and isolated organelles. Immunofluorescence revealed that pharmacologic inhibition of oncogenic MAPK signaling reduces DRP1-S616Ⓟ levels, which correlates with mitochondrial hyperfusion, while immunohistochemistry showed that elevated DRP1-S616Ⓟ expression in human tissues correlates with BRAF^V600E disease. Conclusions: 3G11 is a new recombinant antibody for detecting DRP1-S616Ⓟ and supports studies of mitochondrial division in cancer. Together, these findings establish 3G11 as a specific, versatile, renewable, and cost-effective tool for studying mitochondrial division, with strong potential for clinical applications. Full article

Background/Objectives: The OPA1 gene encodes a dynamin-related GTPase essential for mitochondrial fusion. Variants in OPA1 are a major cause of autosomal dominant optic atrophy (DOA). A subset of DOA patients exhibits hearing loss, often manifesting as auditory neuropathy spectrum disorder (ANSD). In this study, we aimed to describe the frequency of OPA1-related hearing loss in a large cohort of patients with hearing loss and to explore the genotype–phenotype correlations and appropriate interventions. Methods: A total of 18,475 Japanese patients with hearing loss were recruited. Targeted massively parallel sequencing of 158 deafness-related genes was performed, and individuals with OPA1 variants were identified. Clinical data, including age of onset, audiological findings, and systemic features, were retrospectively reviewed. Results: Ten individuals from eight independent families carrying OPA1 variants were identified. Three variants were classified as pathogenic or likely pathogenic, while five were variants of uncertain significance. Hearing loss was typically post-lingual in onset and progressive, with predominantly mild-to-moderate severity. Missense variants tended to be associated with DOA-plus phenotypes and ANSD. Five patients obtained only limited benefit from hearing aids, whereas one patient who received a cochlear implant achieved good speech perception. Conclusions: OPA1 is a rare causative gene for hearing loss and is frequently associated with the ANSD phenotype. Affected individuals exhibited phenotypic heterogeneity, which may reflect incomplete penetrance or the influence of mitochondrial DNA-related factors. Full article

Airborne particulate matter with a diameter of <10 μm (PM₁₀) can damage the corneal epithelium by inducing oxidative stress, disrupting the NRF2 antioxidant pathway, and triggering epithelial barrier dysfunction and inflammation. However, the role of mitochondria in mediating PM₁₀-induced damage remains unexplored. This study investigated the impact of PM₁₀ on mitochondrial homeostasis in both immortalized human corneal epithelial cells (HCE-2) and the mouse corneal epithelium, as well as the protective effects of SKQ1. For in vivo assessment, female C57BL/6 mice were exposed to either control air or PM₁₀ (±SKQ1) in a whole-body exposure chamber for 2 weeks (3 h/day, 5 days/week, with weekends off). In vitro, HCE-2 cells were exposed to 100 μg/mL PM₁₀ (±SKQ1) for 24 h, and mitochondrial function and morphology were evaluated. In vitro, PM₁₀ significantly impaired mitochondrial function by reducing basal, maximal, and ATP-linked respiration; reserve capacity; and coupling efficiency compared to the control and SKQ1 groups. PM₁₀ also downregulated mitofusin1 (MFN1) and optic atrophy1 (OPA1) and upregulated dynamin-related protein1 (DRP1) and mitochondrial fission protein1 (FIS1) in HCE-2 cells. In addition, PM₁₀ exposure significantly decreased the mitochondrial membrane potential; mitochondrial DNA copy number; and cytochrome c oxidase subunit 4 isoform 1 (COX4i1), mitochondrial transcription factor A (TFAM), and peroxisome proliferator-activated receptor gamma coactivator 1 alpha (PGC-1α) levels. SKQ1 pre-treatment significantly attenuated these effects. In vivo, PM₁₀ exposure significantly decreased the levels of MFN1, TFAM, COX4i1, and superoxide dismutase (SOD2), whereas SKQ1 treatment significantly reversed these effects. Overall, these findings demonstrate that PM₁₀ exposure induces mitochondrial fragmentation, disrupts mitochondrial biogenesis and quality control, and reduces mitochondrial respiration, resulting in mitochondrial dysfunction. SKQ1 effectively reversed these changes, suggesting its potential as a therapeutic strategy to protect corneal epithelial cells from PM₁₀-induced mitochondrial damage. Full article

Background/Objectives: Alzheimer’s disease (AD) is characterized by progressive neurodegeneration driven by interconnected mechanisms, including oxidative stress, mitochondrial dysfunction, neuroinflammation, synaptic impairment, and abnormal protein aggregation. MicroRNAs (miRNAs) have emerged as post-transcriptional regulators of these complex pathways; however, efficient delivery remains a major limitation. Small extracellular vesicles (sEVs) have been proposed as biologically compatible carriers for miRNA delivery. Methods: In this study, milk-derived sEVs were isolated, characterized, and loaded with microRNA-137-5p (miR-137-5p). Their effects were evaluated in an amyloid-β (Aβ)-induced in vitro AD model using SH-SY5Y human neuroblastoma cells. Oxidative stress markers, including reactive oxygen species (ROS), malondialdehyde (MDA), superoxide dismutase (SOD), lactate dehydrogenase (LDH), and glutathione peroxidase 1 (GPX1), were assessed. Inflammation- and neuroprotection-related gene expression analyses included intercellular adhesion molecule 1 (ICAM1), tumor necrosis factor alpha (TNF-α), and brain-derived neurotrophic factor (BDNF). Cytoskeletal injury was evaluated using neurofilament light chain (NfL). Mitochondrial stress markers included cytochrome c (Cyt-c), 8-hydroxy-2′-deoxyguanosine (8-OHdG), PTEN-induced kinase 1 (PINK1), dynamin-1-like protein (DNM1L), and mitochondrial transcription factor A (TFAM). Synaptic and extracellular matrix-associated proteins, including complexin-2 (CPLX2), SPARC-related modular calcium-binding protein 1 (SMOC1), and receptor tyrosine kinase-like orphan receptor 1 (ROR1), as well as AD-related biomarkers, including total tau, phosphorylated tau at threonine 181 (pTau-181), phosphorylated tau at threonine 217 (pTau-217), and amyloid-β 1–40 (Aβ1–40), were evaluated using molecular and biochemical approaches. Results: Aβ exposure was associated with increased oxidative stress, inflammatory activation, mitochondrial and cytoskeletal alterations, synaptic-related disturbances, and elevations in tau- and amyloid-associated proteins. Treatment with unloaded sEVs was associated with partial modulation of several parameters, whereas miR-137-5p-loaded sEVs were consistently associated with normalization of multiple pathological markers toward control levels. Conclusions: These findings indicate that miR-137-5p-enriched sEVs may represent a useful experimental platform for multi-target modulation of AD-related cellular alterations. Further mechanistic and in vivo studies are required to clarify translational relevance. Full article

Background/Objectives: Microbe-derived extracellular vesicles (MEVs) provide a biocompatible, naturally derived platform for drug delivery. Methods: We encapsulated doxorubicin in Lactobacillus plantarum-derived EVs and evaluated their ability at delivering doxorubicin to colorectal cancer cells in vitro. Endocytosis inhibitors were used to investigate the mechanisms by which the MEVs entered the cells. Results: The MEVs maintained structural stability under physiological conditions. Cellular internalization of doxorubicin-loaded MEVs involve clathrin/caveolae-dependent endocytosis, and dynamin- and clathrin-mediated pathways. Conclusions: These findings highlight the role of the microbe–cancer cell biointerface in mediating drug uptake and enabling intracellular delivery. The study supports the potential of MEVs as nanocarriers for anticancer drugs and provides mechanistic insights into the intracellular trafficking pathways that influence drug activity. Full article