Search Results (2,393)

The family of Nek kinases has 11 human members that are conserved in their kinase domains but diverse in their regulatory domains. Functionally, they can be associated with diverse aspects of cell cycle regulation, from mitosis and primary cilia function to centrosome disjunction in the G2 phase and checkpoints of the DNA damage response. However, novel functional contexts have emerged in recent years, including regulatory roles of Neks 1, 4, 5, and 10 in mitochondrial metabolic and morphological homeostasis. We recently generated, by CRISPR-Cas9 technology, a DU-145 prostate cancer cell line, with an NEK6 gene knockout. Here, we focus on a detailed characterization of changes in this cell line, in mitochondrial respiration function and morphology. DU-145 NEK6 knockout cells exhibited reduced mitochondrial respiration and a fragmented phenotype in electron microscopy, with reduced mitochondrial cristae numbers. Alterations in mitochondrial architecture and respiration were correlated with increased expression of anaerobic glycolytic proteins (HK2, PFKP, and LDHA) and decreased expression of PDH, an enzyme of aerobic glycolysis. Molecular analysis by Western blot revealed decreased levels of mitochondrial mass and biogenesis protein markers (TOM20, TFAM), without alterations in other markers such as VDAC1/3 or mtDNA copy number in the NEK6 knockout cells. Furthermore, the regulators of mitochondrial fusion/fission are altered in the knockout cells (decrease in the Long-OPA1:Short-OPA1 ratio and DRP1 total level), which is associated with an increase in endoplasmic reticulum–mitochondria contact at ≤20 nm observed in transmission electron microscopy (TEM) image analysis. Using analysis of TEM micrographs, we found an increase in the autophagic structures (autophagosome, amphisome, and autolysosome), with mitochondria as cargo in some structures, which was correlated with a decrease in LC3A/B and an increase in the BECLIN1 total level, and with an increase in acidic vesicles approximation, suggesting that reduction in TOM20 and TFAM without alterations in VDAC1/3 and mtDNA copy number might be related to mitochondrial degradation through autophagy. Together, our data suggest a new role for NEK6 in regulating mitochondrial homeostasis, where its loss alters mitochondrial morphology and respiration, and could be associated with an increase in the degradation of the dysfunctional mitochondria through autophagy. Full article

Osteoporosis is a systemic skeletal disorder characterized by low bone mass, microarchitectural deterioration, and an increased risk of fracture. Its pathogenesis is closely associated with disturbances in energy metabolism, particularly glucose metabolic reprogramming in bone cells. Under osteoporotic conditions, the balance between osteoblasts and osteoclasts is disrupted, accompanied by impaired oxidative phosphorylation, dysregulated glycolysis, and reduced tricarboxylic acid cycle efficiency, ultimately leading to mitochondrial dysfunction. These metabolic alterations result in an insufficient energy supply and accelerate bone loss. Accordingly, the modulation of key enzymes involved in glucose metabolism has emerged as a promising therapeutic strategy. Strategies include the use of natural compounds, traditional Chinese medicine formulas, and specific inhibitors to modulate glucose metabolism processes and related pathways, thereby restoring cellular energy homeostasis and bone remodeling balance. This review summarizes pharmacological agents regulating glucose metabolism and proposes a hierarchical framework for therapeutic prioritization: first, inhibiting pathological glycolysis in osteoclasts (particularly via LDHA and PKM2). Second, restoring oxidative phosphorylation in osteoblasts (e.g., via COX I–V or ATP synthase). And third, employing multi-target traditional Chinese medicine formulas as complementary strategies. By establishing this cell-type-specific and pathway-specific hierarchy, the review aims to provide a theoretical basis for future research on metabolic interventions in bone diseases. Full article

Tumour necrosis factor-alpha (TNF-α) disrupts bioenergetic homeostasis in skeletal muscle cells through the suppression of ion-dependent ATPase activities, mitochondrial depolarisation, and impairment of antioxidant defences. Carvacrol, a phenolic monoterpenoid constituent of thyme and oregano essential oil, has been shown to exert cytoprotective effects in TNF-α-challenged L6 rat myoblasts. The mechanistic basis of these effects, specifically the relationship between membrane-associated ATPase function, mitochondrial polarisation status, and transcriptional regulation of metabolic stress-response genes, has not been formally characterised. L6 rat myoblasts were exposed to TNF-α (10 ng/mL, 1 h), then treated with carvacrol (6.25 µg/mL, 24 h) in a post-inflammatory rescue paradigm. Cell viability (MTT), membrane integrity (LDH), ion-dependent ATPase activities (Na⁺/K⁺, Ca²⁺, Mg²⁺), antioxidant enzyme activities (catalase, SOD), mitochondrial membrane potential (Muse™ MitoPotential flow cytometry), and SIRT1/AMPK mRNA expression were quantified. TNF-α significantly suppressed Na⁺/K⁺, Ca²⁺, and Mg²⁺-dependent ATPase activities (all p < 0.001), consistent with impaired membrane-associated bioenergetic function. Post-TNF-α carvacrol treatment partially restored all three ATPase activities (p < 0.05) and reduced the proportion of mitochondrially depolarised cells from 31.65 ± 4.25% to 19.0 ± 2.6% (p < 0.05). LDH release, catalase activity, and SOD activity were also significantly modulated. At the transcriptional level, carvacrol increased SIRT1 mRNA by 1.6-fold and AMPK mRNA by 2.0-fold relative to TNF-α-treated cells. An integrative bioenergetic model is proposed in which carvacrol’s membrane-intercalating properties restore the phospholipid environment required for ATPase conformational cycling, attenuating the Ca²⁺ overload that drives mitochondrial permeability transition, and thereby partially preserving Δψm. Transcriptional upregulation of SIRT1 and AMPKα may represent an adaptive response to residual energetic stress. The mechanistic relationships among these endpoints and the causal contribution of SIRT1 and AMPK to observed bioenergetic changes require protein-level and pathway-specific experimental validation. Full article

Mitochondria–endoplasmic reticulum contact sites (MERCs) are known as the specialized areas that are involved in a large number of intracellular signaling pathways that regulate Ca²⁺ homeostasis, lipid transport, mitochondrial dynamics, cell death, and autophagy. Understanding MERC dynamics has important therapeutic implications in cancer, as these contacts regulate fundamental cellular processes and MERCs represent promising targets for therapeutic interventions aimed at improving cancer treatment outcomes. Despite the accumulated data, the role of MERCs in carcinogenesis still remains unknown; thus, it seems promising to search for new tools facilitating the study of MERCs in tumor cells. The structure of MERCs can be examined in great detail using transmission electron microscopy (TEM). Currently, several hundred TEM images are required to obtain reliable data on these contacts. The speed of data processing can be significantly improved by using fast and accurate image analysis techniques based on deep learning models. In this study, five U-Net models with a ResNet34 encoder network were evaluated, including the basic U-Net-Vanilla architecture as well as models incorporating various attention blocks and blocks capturing multilevel image structure, for the segmentation of mitochondria and the endoplasmic reticulum (ER). The best performance on the test dataset was demonstrated by the U-Net-scSE network, with F1 scores of 0.872 for mitochondria and 0.744 for the ER being achieved. Two models were tested for their ability to leverage pre-training on external datasets (Lucchi++, Kasthuri++, and DeepPi-EM). Additionally, models pre-trained on the CEM500K dataset were evaluated after the parameters had been tuned on the data. It was demonstrated by the results that pre-training or the use of pre-trained networks did not lead to an improvement in the IoU and F1 metrics on the test dataset. Subsequent image analysis was conducted to assess two types of MERCs in the segmented images. Finally, the free and user-friendly UltraNet web server was developed for automated analysis of mitochondria, ER, and MERCs using TEM images. Full article

Females with iron overload suffer from follicular dysplasia, and effective therapeutic strategies for preserving fertility remain lacking. As a natural aliphatic polyamine, spermidine exerts antioxidant activity and plays an anti-ferroptosis role in the pathogenesis of various diseases. However, the role and underlying mechanism of spermidine in iron overload-induced ovarian ferroptosis remain largely elusive. This study aimed to investigate the therapeutic potential of spermidine against iron overload-induced ferroptosis in ovarian granulosa cells and elucidate its molecular mechanism. As a result, iron overload models were established in female mice (in vivo, ferrous sulfate) and porcine ovarian granulosa cells (in vitro, ferric ammonium citrate), with spermidine administered at 3 mM (in vivo) or 150 μM (in vitro). Ferritin heavy chain (FHC) and solute carrier family 7 member 11 (SLC7A11) silencing were performed via siRNA transfection, and relevant controls were set. In vivo studies showed that spermidine elevated serum estradiol and progesterone levels, enhanced ovarian catalase (CAT) and superoxide dismutase (SOD) activities, improved granulosa cell mitochondrial morphology, and increased estrous cycle regularity from 35.6% (high-iron group) to 63.1%. In vitro, spermidine improved ferric ammonium citrate (FAC)-impaired cell viability; attenuated reactive oxygen species (ROS) accumulation; upregulated FHC, Nrf2/p-Nrf2/GPX4, SLC7A11 and anti-müllerian hormone (AMH) expression; and inhibited excessive autophagy (decreased LC3BII/I ratio). Mechanistically, spermidine activated AKT-mediated autophagy, modulated iron homeostasis and glutathione (GSH) synthesis via FHC, alleviated ferroptosis-related Nrf2/p-Nrf2/HO-1 pathway overactivation, reduced lipid peroxidation and DNA damage, and restored mitochondrial function. SLC7A11 silencing disrupted glutathione metabolism, induced mitochondrial ROS accumulation, and inhibited autophagy. Proteomic analysis identified microsomal glutathione S-transferase 3 (MGST3) as a potential key downstream target of spermidine in suppressing SLC7A11-mediated ferroptosis. This study reveals a novel therapeutic strategy wherein spermidine protects against ovarian ferroptosis and preserves ovarian function by regulating iron homeostasis through the FHC/SLC7A11 axis. Full article

The discovery of melatonin as a multifunctional free radical scavenger and its possible synthesis in the mitochondrial matrix of peripheral eukaryotic somatic cells highlights a critical new perspective on the importance of this indole. Experimental evidence supporting these findings is substantial, but there are still lingering questions whether melatonin is a direct radical scavenger in vivo and whether it is synthesized in the mitochondrial matrix. We systematically analyze the innovative experimental approaches that support melatonin’s radical scavenging actions and assess the compelling data supporting its production in mitochondria. Melatonin concentrations are reportedly higher in this organelle than in other cellular compartments. Proteins for the enzymes required to convert serotonin to melatonin are present in the mitochondrial matrix and purified mitochondria synthesize melatonin. In the mitochondrial matrix, melatonin is likely located within the “damage radius” of highly reactive oxygen species. We also summarize novel actions of melatonin associated with its regulation of membrane fluidity, determine the molecular composition of membrane lipid rafts, and modulate liquid–liquid phase separation and biomolecular condensates intracellularly. If the findings discussed herein continue to be validated, melatonin would be in an optimal position to function as an antioxidant and may be a key driver in the context of preserving mitochondrial redox homeostasis and disease mitigation. Full article

Type 2 diabetes mellitus is a relevant cardio–renal–metabolic disorder in which chronic low-grade inflammation and oxidative stress have a crucial function in linking insulin resistance, endothelial dysfunction, β-cell impairment, and progressive organ injury. In this context, nutrition has emerged as a key modifiable determinant of metabolic homeostasis, capable of influencing inflammatory signalling, redox balance, mitochondrial function, and gut microbiota–host interactions. The objective of this review is to critically summarise the mechanistic connections among inflammation, oxidative stress, and diabetes progression, and to investigate how dietary factors and patterns, as well as nutrition-responsive biomarkers, influence these pathways and their cardiorenal consequences. We discuss the effects of macronutrient quality, dietary fibre, fatty acids, polyphenols, and specific micronutrients, including vitamin C, vitamin E, selenium, zinc, and magnesium, as well as the role of Mediterranean, DASH, and plant-based diets in improving glycaemic control, endothelial function, and cardio-renal risk profiles. We also summarise established and emerging biomarkers of inflammation and oxidative stress that may improve risk stratification and the evaluation of nutrition-based interventions. Overall, current evidence supports a shift from a purely glucose-centred approach toward an integrated model in which dietary modulation of inflammatory and oxidative pathways helps reduce cardiovascular and renal risk. However, heterogeneity of interventions, variability in biomarker assessment, and interindividual differences in dietary response represent major limitations. Future research should focus on biomarker-informed, precision-oriented nutritional approaches integrated within contemporary cardio–renal–metabolic care. Full article

Background/Objectives: Excessive dietary inorganic phosphate (Pi) as a food additive poses potential health risks. Methods: This study investigated the impact of excessive dietary inorganic phosphate on intestinal and immune homeostasis in mice using gradient Pi exposure combined with an inflammatory model. Results: Pi overload induced atrophy in the thymus, spleen, and kidney; damaged the intestinal barrier; reduced the villus height-to-crypt-depth ratio; and decreased goblet cell numbers. Altered levels of serum sIgA and IgE, as well as intestinal IgA, IgG, IgE, and IgM, together with decreased IFN-α, indicated altered levels of immunoglobulins and cytokines under Pi treatment. Proteomic analysis revealed differential expression of key proteins, including CNTFR and Bcl2l1 in the JAK/STAT pathway and metabolic regulators CPT1α and IDH1, when comparing Pi-treated mice with the control group. Conclusions: These preliminary findings suggest that Pi may affect intestinal mucosal barrier function and systemic immune response through immune regulation and mitochondrial metabolic pathways, providing preliminary insight into the potential health implications of Pi overconsumption in humans. Full article

Methylglyoxal (MG) is a reactive dicarbonyl compound generated mainly as a byproduct of glycolysis. Excess accumulation of MG can promote protein glycation and the formation of advanced glycation end-products (AGEs), which have been associated with oxidative stress, inflammation, mitochondrial dysfunction, and cellular damage. These processes are implicated in the development of several chronic conditions, including diabetes, neurodegenerative disorders, cardiovascular disease, and age-related decline. The glyoxalase system, comprising Glyoxalase I (Glo1) and Glyoxalase II (Glo2), serves as a key cellular defense mechanism that detoxifies MG and helps maintain dicarbonyl homeostasis. Among these enzymes, Glo1 catalyzes the conversion of MG into less reactive intermediates in a glutathione (GSH)-dependent manner. A range of natural compounds and dietary phytochemicals, including sulforaphane, resveratrol, α-lipoic acid, selenium, vitamin D3, and N-acetylcysteine, have been reported to modulate Glo1 activity through transcriptional regulation, antioxidant effects, or support of intracellular GSH levels. Evidence from preclinical and limited human studies suggests that these compounds may help reduce MG burden and AGE formation, although their effects are often indirect and context-dependent. However, several challenges remain, including variable bioavailability, dose-dependent responses, disease-specific differences in Glo1 regulation, and the lack of standardized biomarkers and adequate clinical validation. This review examines the MG–Glo1 axis as a mechanistic framework linking metabolic stress to disease and evaluates natural compounds as context-dependent modulators of this pathway. By integrating mechanistic insights with emerging in vivo and clinical evidence, this work highlights the potential, while acknowledging the limitations, of targeting Glo1 as a translational strategy for managing glycation-associated disorders. Full article

Mitochondrial electron transport chain (ETC) impairment triggers mitochondrial unfolded protein response (UPR^mt) that promotes mitochondrial homeostasis, yet the nuclear factors that mediate these responses remain incompletely defined. Here, we identify GLDI-8 as a nuclear factor required for robust activation of the hsp-6p::gfp UPR^mt reporter induced by ETC dysfunction in Caenorhabditis elegans. Depletion of gldi-8 markedly compromises mitochondrial stress-induced hsp-6p::gfp reporter activation, and transgenic rescue restores the response, supporting a specific requirement for GLDI-8 in this pathway. Mitochondrial stress promotes nuclear accumulation of GLDI-8; however, a GLDI-8 transcriptional (promoter) reporter shows no detectable induction under the same conditions, suggesting that regulation occurs at the post-transcriptional level. Genetic analysis further shows that stress-induced nuclear translocation of GLDI-8 is not abolished by atfs-1 knockdown, and GLDI-8 is dispensable for DVE-1 nuclear translocation under mitochondrial stress. Together, these findings establish GLDI-8 as a mitochondrial stress-responsive nuclear factor that contributes to ETC impairment–induced transcriptional responses and adds to the complex regulatory network underlying the UPR^mt. Full article

Decidualization in the human endometrium is not merely a hormone-dependent differentiation process; rather, it represents a multilayered adaptive program characterized by the tight integration of immune regulation, metabolic reprogramming, and cellular stress responses. In this review, endoplasmic reticulum (ER) stress and the associated unfolded protein response (UPR) are proposed as central regulatory mechanisms governing this process. Triggered by increased protein synthesis and secretory demand, UPR activation under physiological conditions preserves proteostasis and supports the secretory capacity of stromal cells. In contrast, chronic or dysregulated activation leads to a maladaptive response characterized by apoptosis, inflammation, and metabolic dysfunction. UPR signaling pathways shape immune tolerance through their effects on macrophage polarization, uterine natural killer (uNK) cell function, and T cell balance. At the metabolic level, adenosine monophosphate-activated protein kinase (AMPK) regulates cellular adaptation through bidirectional interactions with mitochondrial function and redox homeostasis. Within this framework, the ER stress–immune–metabolic axis operates not as a linear pathway but as a dynamic network incorporating multiple feedback loops, thereby constituting a critical threshold mechanism that determines the success of decidualization. Disruption of this axis provides a shared mechanistic basis for pathologies such as recurrent implantation failure, pregnancy loss, and preeclampsia. From a therapeutic perspective, agents including chemical chaperones, UPR modulators, AMPK activators, and anti-inflammatory compounds hold translational potential by targeting these pathological feedback circuits. However, key knowledge gaps remain, particularly regarding the cell type-specific and temporal regulation of ER stress, the molecular boundaries defining the transition from adaptive to pathological states, and interspecies differences. Future studies employing single-cell omics approaches and functional in vivo models will be essential to elucidate the dynamic organization of this axis and to enable the development of targeted and personalized therapeutic strategies. Full article

Parkinson’s disease (PD) is a prevalent neurodegenerative disorder, characterized by the loss of dopaminergic neurons in the substantia nigra pars compacta and the accumulation of Lewy bodies. Over recent decades, various cellular mechanisms underlying PD have been elucidated, including autophagy, mitochondrial dysfunction, neuroinflammation, and axonal transport. Among them, axonal transport plays a critical role in maintaining the dynamic homeostasis of proteins, membrane-bound organelles, and cellular metabolism within neurons. Unfortunately, a comprehensive overview of axonal transport in PD remains absent. In this review, we synthesized the current literature on axonal transport in PD, leveraging neurotoxic and genetic models to explore the causes and consequences of axonal transport alterations in PD. Through this summary, we aim to deepen our understanding of PD pathogenesis and provide potential therapeutic targets for intervention. Full article

Regular exercise and physical activity are beneficial in reducing the risk and progression of ischemic stroke. However, the underlying physiological mechanisms by which exercise confers these protective effects remain incompletely understood. Disruption of mitochondrial homeostasis is key contributors to the pathophysiology of ischemic stroke. Exercise training effectively attenuates the onset and progression of ischemic stroke by significantly maintaining mitochondrial homeostasis, including improving mitochondrial biogenesis, balancing mitochondrial dynamics, maintaining mitochondrial redox, promoting mitophagy and mitochondrial transport. This review systematically summarizes the beneficial effects of exercise in the context of ischemic stroke and highlights the critical link between mitochondrial homeostasis disruption and stroke pathology. By providing a detailed analysis of the underlying molecular mechanisms, this study offers novel insights into exercise-based therapeutic strategies for ischemic stroke. Full article

The global population is ageing rapidly; adults aged ≥ 60 years are projected to exceed 2 billion by 2050. Ageing is a major risk factor for chronic and degenerative disorders and is increasingly viewed as a modifiable biological program. Oxidative stress is a central driver: sustained ROS/RNS accumulation damages lipids, proteins and nucleic acids and amplifies mitochondrial dysfunction, inflammaging, cellular senescence, impaired autophagy and telomere instability. Targeting these shared mechanisms may therefore deliver multi-disease benefits beyond single-disease therapy. Medicinal plants provide chemically defined monomers that can act as direct antioxidants and, more importantly, restore redox homeostasis by modulating conserved signaling axes, including Nrf2/FOXO/SIRT1, AMPK/mTOR and NF-κB. However, the current evidence base remains highly heterogeneous, and reliable clinical validation is still limited. In this review, we summarize studies published over the last decade on medicinal plant-derived monomers with reported anti-ageing relevance in the context of oxidative stress and redox homeostasis. We compare major redox-centered pathways, molecular targets, model systems, and outcome measures, and evaluate the evidence with attention to its strength, consistency, and translational relevance. Particular emphasis is placed on current limitations, including model dependence, variable bioavailability, uncertain dose–exposure relationships, and the lack of well-designed clinical studies. These considerations are intended to provide a more cautious and evidence-based framework for future mechanistic and translational research. Full article

Background: Macrophages were long regarded as passive executors of erythrophagocytosis responsible for systemic iron recycling. However, increasing evidence has reframed them as immunometabolic hubs that sense diverse environmental cues to modulate systemic iron homeostasis. Main body: This review examines the molecular architecture underlying macrophage iron metabolism and outlines how iron metabolic processes are dynamically regulated across spatial and temporal scales through the integration of mechanotransductive, mitochondrial, and epigenetic signaling pathways. Across disease contexts, macrophage iron handling displays marked heterogeneity, exemplified by contact-dependent iron transfer in tumors and ferroptosis-driven instability in cardiovascular disease. In cardiovascular pathologies, iron overload is associated with enhanced ferroptosis-related cascades that contribute to atherosclerotic plaque instability. Furthermore, at mucosal interfaces, host–pathogen competition over nutritional immunity highlights epigenetic strategies by which pathogens perturb host iron machinery. Conclusions: Linking these mechanistic insights to clinical translation, emerging therapeutic strategies are discussed that move beyond non-specific systemic iron chelation toward more targeted interventions. These include engineering macrophages for targeted drug delivery, exploiting nanomedicine-based redox modulation to influence macrophage phenotypes, and non-invasive regulation via the gut microbiota–epigenetic axis. Collectively, elucidating macrophage iron metabolic networks provides a conceptual framework for the development of precision approaches to inflammatory, metabolic, and malignant diseases. Full article