Search

A decline in mitochondrial function is a hallmark of aging and neurodegenerative diseases. It has been proposed that changes in mitochondrial morphology, including fragmentation of the tubular mitochondrial network, can lead to mitochondrial dysfunction, yet the mechanism of this loss of function is unclear. Most proteins contained within mitochondria are nuclear-encoded and must be properly targeted to the mitochondria. Here, we report that sustained mRNA localization and co-translational protein delivery leads to a heterogeneous protein distribution across fragmented mitochondria. We find that age-induced mitochondrial fragmentation drives a substantial increase in protein expression noise across fragments. Using a translational kinetic and molecular diffusion model, we find that protein expression noise is explained by the nature of stochastic compartmentalization and that co-translational protein delivery is the main contributor to increased heterogeneity. We observed that cells primarily reduce the variability in protein distribution by utilizing mitochondrial fission-fusion processes rather than relying on the mitophagy pathway. Furthermore, we are able to reduce the heterogeneity of the protein distribution by inhibiting co-translational protein targeting. This research lays the framework for a better understanding of the detrimental impact of mitochondrial fragmentation on the physiology of cells in aging and disease.

Activation of PINK1 and Parkin in response to mitochondrial damage initiates a response that includes phosphorylation of RAB7A at Ser72. Rubicon is a RAB7A binding negative regulator of autophagy. The structure of the Rubicon:RAB7A complex suggests that phosphorylation of RAB7A at Ser72 would block Rubicon binding. Indeed, in vitro phosphorylation of RAB7A by TBK1 abrogates Rubicon:RAB7A binding. Pacer, a positive regulator of autophagy, has an RH domain with a basic triad predicted to bind an introduced phosphate. Consistent with this, Pacer-RH binds to phosho-RAB7A but not to unphosphorylated RAB7A. In cells, mitochondrial depolarization reduces Rubicon:RAB7A colocalization whilst recruiting Pacer to phospho-RAB7A-positive puncta. Pacer knockout reduces Parkin mitophagy with little effect on bulk autophagy or Parkin-independent mitophagy. Rescue of Parkin-dependent mitophagy requires the intact pRAB7A phosphate-binding basic triad of Pacer. Together these structural and functional data support a model in which the TBK1-dependent phosphorylation of RAB7A serves as a switch, promoting mitophagy by relieving Rubicon inhibition and favoring Pacer activation.

The central nervous system coordinates peripheral cellular stress responses, including the unfolded protein response of the mitochondria (UPRMT); however, the contexts for which this regulatory capability evolved are unknown. UPRMT is up-regulated upon pathogenic infection and in metabolic flux, and the olfactory nervous system has been shown to regulate pathogen resistance and peripheral metabolic activity. Therefore, we asked whether the olfactory nervous system in Caenorhabditis elegans controls the UPRMT cell nonautonomously. We found that silencing a single inhibitory olfactory neuron pair, AWC, led to robust induction of UPRMT and reduction of oxidative phosphorylation dependent on serotonin signaling and parkin-mediated mitophagy. Further, AWC ablation confers resistance to the pathogenic bacteria Pseudomonas aeruginosa partially dependent on the UPRMT transcription factor atfs-1 and fully dependent on mitophagy machinery. These data illustrate a role for the olfactory nervous system in regulating whole-organism mitochondrial dynamics, perhaps in preparation for postprandial metabolic stress or pathogenic infection.

Pulmonary fibrosis is a chronic interstitial lung disease with no curative therapeutic treatment, leading to significant mortality. The aims of this study were to investigate the regulatory mechanisms of mitophagy in the progression of pulmonary fibrosis. Through bioinformatics analysis, we identified the downregulation of long-chain fatty acyl-CoA synthetase 1 (ACSL1) as being associated with the severity of pulmonary fibrosis. A pulmonary fibrosis model was established through bleomycin (BLM) exposure both in vivo and in vitro. Mitoquinone (MitoQ) pretreatment significantly decreased redox damage, stabilized mitochondrial membrane potential (MMP), improved mitochondrial dynamics, and activated PINK1/Parkin-mediated mitophagy, thereby alleviating pulmonary fibrosis. In vitro, overexpression of ACSL1 mitigated mitochondrial damage and restored PINK1/Parkin-mediated mitophagy under BLM exposure. In contrast, ACSL1 inhibition exacerbated pulmonary fibrosis, and these adverse effects could not be reversed by MitoQ treatment. Taken together, our study reveals a novel mechanism underlying the pathogenesis of pulmonary fibrosis and suggests a potential therapeutic target for its treatment. [ABSTRACT FROM AUTHOR]

Photoperiod is a pivotal factor in affecting testicular function and spermatogenesis in seasonal‐breeding animals. Mitophagy is essential for spermatogenesis, but its association with seasonal photoperiods has not been studied extensively. To explore this, we exposed male Brandt's voles (Lasiopodomys brandtii) to long‐photoperiod (LP, 16 h/day) and short‐photoperiod (SP, 8 h/day) conditions from their embryonic stages. Our results indicated that testis weight, volume, and relative testes weight were all significantly increased in LP compared to SP. Additionally, blood testosterone levels were markedly higher in LP than SP. Histological examination revealed that seminiferous diameter and epithelium thickness were greater in LP, with an increased abundance of germ cell types and cell numbers compared to SP. RT‐qPCR analysis showed that mitophagy‐promoting genes, such as Pink1, Prkn, Tomm7, Mnf2, Lc3, Optn, Gabarap, and Nbr1 were all upregulated in LP. Fluorescence in situ hybridization indicated that Pink1 expression was present in spermatogonia in SP, while in LP, Pink1 expression extended to almost all germ cell types with significantly higher mean optical density. Prkn expression was found in all germ cell types in both LP and SP, with a significantly higher mean optical density of 10‐week‐old LP males. Transmission electron microscopy showed normal mitochondrial morphology with clear membranes in SP, while the LP group had reduced cristae in mitochondria and damaged mitochondria undergoing autophagy. This study suggests that mitophagy may be involved in the photoperiodic spermatogenesis in Brandt's voles, providing insights into the role of photoperiod in seasonal reproduction in wild animals. [ABSTRACT FROM AUTHOR]

Mitochondrial abnormalities in lung epithelial cells have been associated with chronic obstructive pulmonary disease (COPD) pathogenesis. Cigarette smoke (CS) can induce alterations in the molecular pathways regulating mitochondrial function in lung epithelial cells. Recently, heated tobacco products (HTPs) have been marketed as harm reduction products compared with regular cigarettes. However, the effects of HTP emissions on human alveolar epithelial cell metabolism and on the molecular mechanisms regulating mitochondrial content and function are unclear. In this study, human alveolar epithelial cells (A549) were exposed to cigarette or HTP emissions in the form of liquid extracts. The oxygen consumption rate of differently exposed cells was measured, and mRNA and protein abundancy of key molecules involved in the molecular regulation of mitochondrial metabolism were assessed. Furthermore, we used a mitophagy detection probe to visualize mitochondrial breakdown over time in response to the extracts. Both types of extracts induced increases in basal-, maximal- and spare respiratory capacity, as well as in cellular ATP production. Moreover, we observed alterations in the abundancy of regulatory molecules controlling mitochondrial biogenesis and mitophagy. Mitophagy was not significantly altered in response to the extracts, as no significant differences compared to vehicle-treated cells were observed. • cigarette smoke extract (CSE) and heated tobacco product extract (HTPE) induce an increase in cellular respiration in human alveolar epithelial cells. • CSE and HTPE affect the transcriptional program driving mitochondrial biogenesis. • Mitophagy was not induced by CSE or HTPE treatment. • Our study suggests a similar impact of cigarette and HTP emission on mitochondrial energy metabolism and on the molecular mechanisms regulating mitochondrial activity and content. [ABSTRACT FROM AUTHOR]

Objective(s): This study aimed to investigate the effect of 8-week high-intensity interval training (HIIT) on lactate-induced mitophagy in the hippocampus of rats with type 2 diabetes. Materials and Methods: 28 Wistar male rats were divided into four groups randomly: (i) control (Co), (ii) exercise (EX), (iii) type 2 diabetes (T2D), and (iv) type 2 diabetes + exercise (T2D + Ex). The rats in the T2D and T2D + Ex groups were fed a high-fat diet for two months, then a single dose of STZ (35 mg/kg) was injected to induce diabetes. The EX and T2D + Ex groups performed 4-10 intervals of treadmill running at 80-100% of Vmax. Serum and hippocampal levels of lactate, as well as hippocampal levels of monocarboxylate transported (MCT2), sirtuin1 (SIRT1), forkhead box protein O (FOXO3), light chain 3 (LC3), PTEN-induced kinase 1 (PINK1), parkin, beta-amyloid (Aβ), hyperphosphorylated tau protein (TAU), Malondialdehyde (MDA), and antioxidant enzymes were measured. One-way ANOVA and Tukey post-hoc tests were used to analyze the data. Results: Serum and hippocampal levels of lactate as well as hippocampal levels of MCT2, SIRT1, FOXO3, LC3, PINK1, Parkin, and antioxidant enzymes were higher while hippocampal levels of Aβ, TAU, and MDA were lower in T2D+EX compared to T2D group (P-value<0.05) Conclusion: HIIT could improve mitophagy through Lactate-SIRT1-FOXO3-PINK1/Parkin signaling in the hippocampus of rats with T2D reducing the accumulation of Tau and Aβ, which may reduce the risk of memory impairments. [ABSTRACT FROM AUTHOR]

Objectives: Osteoarthritis (OA) is the most common chronic joint degenerative disease. Herein, we investigated long non-coding RNA Opa-interacting protein 5-antisense transcript 1's (OIP5-AS1) in regulating mitophagy during OA. Methods: RNA immunoprecipitation and RNA pull-down verified the relationship between molecules. Cell counting kit-8 detected cell viability. Enzyme-linked immunosorbent assay evaluated inflammatory cytokines secretion. Flow cytometry measured the contents of reactive oxygen species (ROS) and calcium. Immunofluorescence staining analysed TOMM20 and LC3B levels. JC-1 staining was adopted to measure mitochondrial membrane potential. The changes of mitophagy were analysed by transmission electron microscopy. Results: Lipopolysaccharide (LPS) treatment contributed to the decrease of chondrocyte viability, and calcium level and inhibited mitochondrial membrane potential, while elevating the secretion of inflammatory factors, ROS, and TOMM20 expression. OIP5-AS1 overexpression inhibited LPS-induced chondrocyte injury and activated mitophagy. OIP5-AS1 upregulated the peroxisome proliferator–activated receptor-γ (PPAR-γ) mRNA level to regulate adenosine monophosphate–activated protein kinase (AMPK)/v-akt murine thymoma viral oncogene homolog (Akt)/mammalian target of rapamycin (mTOR) signalling by interacting with FUS. PPAR-γ overexpression alleviated LPS-induced chondrocyte injury by activating AMPK/Akt/mTOR signalling. PPAR-γ knockdown reversed the promotion of OIP5-AS1 upregulation on mitophagy. Conclusions: OIP5-AS1 promotes PPAR-γ expression to activate the AMPK/Akt/mTOR signalling, thereby enhancing mitophagy and alleviating OA progression. [ABSTRACT FROM AUTHOR]

Plant pathogens cause devastating diseases, leading to serious losses to agriculture. Mechanistic understanding of pathogenesis of plant pathogens lays the foundation for the development of fungicides for disease control. Mitophagy, a specific form of autophagy, is important for fungal virulence. The role of cardiolipin, mitochondrial signature phospholipid, in mitophagy and pathogenesis is largely unknown in plant pathogenic fungi. The functions of enzymes involved in cardiolipin biosynthesis and relevant inhibitors were assessed using a set of assays, including genetic deletion, plant infection, lipidomics, chemical‐protein interaction, chemical inhibition, and field trials. Our results showed that the cardiolipin biosynthesis‐related gene MoGEP4 of the rice blast fungus Magnaporthe oryzae regulates growth, conidiation, cardiolipin biosynthesis, and virulence. Mechanistically, MoGep4 regulated mitophagy and Mps1‐MAPK phosphorylation, which are required for virulence. Chemical alexidine dihydrochloride (AXD) inhibited the enzyme activity of MoGep4, cardiolipin biosynthesis and mitophagy. Importantly, AXD efficiently inhibited the growth of 10 plant pathogens and controlled rice blast and Fusarium head blight in the field. Our study demonstrated that MoGep4 regulates mitophagy, Mps1 phosphorylation and pathogenesis in M. oryzae. In addition, we found that the MoGep4 inhibitor, AXD, displays broad‐spectrum antifungal activity and is a promising candidate for fungicide development. Summary Statement: This study demonstrated that MoGep4 regulates mitophagy, Mps1 activation and pathogenesis in Magnaporthe oryzae. Additionally, we found that the MoGep4 inhibitor, alexidine dihydrochloride, displays broad‐spectrum antifungal activity and is effective in disease control in the field. [ABSTRACT FROM AUTHOR]

Background: Sepsis-induced myocardial injury (SIMI) is a severe complication of sepsis, contributing significantly to mortality. Mitochondrial dysfunction and dysregulated autophagy are implicated in SIMI pathogenesis. Long non-coding RNA MALAT1 has been associated with various diseases, including sepsis, but its role in SIMI remains unclear. Objective: This study aimed to investigate the role of lncRNA MALAT1 in SIMI, specifically in the regulation of mitochondrial autophagy. Methods: A sepsis-induced cardiomyopathy model was established in mice, and the cardiac tissues were analyzed. The expression of lncRNA MALAT1 was modulated and its effects on mitochondrial autophagy, myocardial injury, inflammation, and apoptosis were assessed. Furthermore, the interaction between MALAT1 and miR-146a was explored, as well as the involvement of the TLR4/NF-kB/MAPK signaling pathway. Results: Activation of mitochondrial autophagy by urolithin A (UA) alleviated SIMI, inflammation, and cardiac dysfunction. Downregulation of MALAT1 enhanced mitochondrial autophagy, stabilized the mitochondrial membrane potential, and inhibited mitochondrial reactive oxygen species (ROS) production, leading to improved cell viability and reduced myocardial injury. Furthermore, MALAT1 interacted with miR-146a, and their modulation influenced mitochondrial autophagy, myocardial injury, and inflammation. The TLR4/NF-kB/MAPK signaling pathway was implicated in these processes. Conclusion: Our findings suggest that lncRNA MALAT1 plays a crucial role in SIMI by modulating miR-146a-mediated mitochondrial autophagy and the TLR4/NF-kB/MAPK signaling pathway. These results provide new insights into the pathogenesis of SIMI and potential therapeutic targets. [ABSTRACT FROM AUTHOR]

Parkinson's disease (PD) is a progressive neurogenerative movement disorder characterized by dopaminergic cell death within the substantia nigra pars compacta (SNpc) due to the aggregation-prone protein α-synuclein. Accumulation of α-synuclein is implicated in mitochondrial dysfunction and disruption of the autophagic turnover of mitochondria, or mitophagy, which is an essential quality control mechanism proposed to preserve mitochondrial fidelity in response to aging and stress. Yet, the precise relationship between α-synuclein accumulation, mitochondrial autophagy, and dopaminergic cell loss remains unresolved. Here, we determine the kinetics of α-synuclein overexpression and mitophagy using the pH-sensitive fluorescent mito-QC reporter. We find that overexpression of mutant A53T α-synuclein in either human SH-SY5Y cells or rat primary cortical neurons induces mitophagy. Moreover, the accumulation of mutant A53T α-synuclein in the SNpc of rats results in mitophagy dysregulation that precedes the onset of dopaminergic neurodegeneration. This study reveals a role for mutant A53T α-synuclein in inducing mitochondrial dysfunction, which may be an early event contributing to neurodegeneration. [ABSTRACT FROM AUTHOR]

To uncover the possible role of TRAF3IP3 in the progression of myocardial infarction (MI), clarify its role in mitophagy and mitochondrial function, and explore the underlying mechanism. GEO chip analysis, RT-qPCR, and LDH release assay were used to detect the expression of TRAF3IP3 in tissues and cells and its effects on cell damage. Immunostaining and ATP product assays were performed to examine the effects of TRAF3IP3 on mitochondrial function. Co-IP, CHX assays, Immunoblot and Immunostaining assays were conducted to determine the effects of TRAF3IP3 on mitophagy. TRAF3IP3 was highly expressed in IR rats and HR-induced H9C2 cells. TRAF3IP3 knockdown can alleviate H/R-induced H9C2 cell damage. In addition, TRAF3IP3 knockdown can induce mitophagy, thus enhancing mitochondrial function. We further revealed that TRAF3IP3 can promote the degradation of NEDD4 protein. Moreover, TRAF3IP3 knockdown suppressed myocardial injury in I/R rats. TRAF3IP3 blocks mitophagy to exacerbate myocardial injury induced by I/R via mediating NEDD4 expression. [ABSTRACT FROM AUTHOR]

The intake of high dietary fat has been correlated with the progression of age‐related macular degeneration (AMD), affecting the function of the retinal pigment epithelium through oxidative stress. A high‐fat diet (HFD) can lead to lipid metabolism disorders, excessive production of circulating free fatty acids, and systemic inflammation by aggravating the degree of oxidative stress. Deletion of the retinal G‐protein‐coupled receptor (RGR‐d) has been identified in drusen. In this study, we investigated how the RGR‐d exacerbates AMD‐like changes under oxidative stress, both in vivo and in vitro. Fundus atrophy became evident, at 12 months old, particularly in the RGR‐d + HFD group, and fluorescence angiography revealed narrower retinal vessels and a reduced perfusion area in the peripheral retina. Although rod electroretinography revealed decreasing trends in the a‐ and b‐wave amplitudes in the RGR‐d + HFD group at 12 months, the changes were not statistically significant. Mice in the RGR‐d + HFD group showed a significantly thinner and more fragile retinal morphology than those in the WT + HFD group, with disordered and discontinuous pigment distribution in the RGR‐d + HFD mice. Transmission electron microscopy revealed a thickened Bruch's membrane along the choriocapillaris endothelial cell wall in the RGR‐d + HFD mice, and the outer nuclear layer structure appeared disorganized, with reduced nuclear density. Kyoto Encyclopedia of Genes and Genomes pathway analysis indicated significantly lower levels of 25(OH)‐vitamin D3 metabolites in the RGR‐d + HFD group. Under oxidative stress, RGR‐d localized to the mitochondria and reduced the levels of the PINK1–parkin pathway. RGR‐d mice fed an HFD were used as a new animal model of dry AMD. Under high‐fat‐induced oxidative stress, RGR‐d accumulated in the mitochondria, disrupting normal mitophagy and causing cellular damage, thus exacerbating AMD‐like changes both in vivo and in vitro. [ABSTRACT FROM AUTHOR]

Mitochondria are crucial organelles that play a central role in cellular metabolism and programmed cell death in eukaryotic cells. Mitochondrial autophagy (mitophagy) is a selective process where damaged mitochondria are encapsulated and degraded through autophagic mechanisms, ensuring the maintenance of both mitochondrial and cellular homeostasis. Excessive programmed cell death in neurons can result in functional impairments following cerebral ischemia and trauma, as well as in chronic neurodegenerative diseases, leading to irreversible declines in motor and cognitive functions. Neuroinflammation, an inflammatory response of the central nervous system to factors disrupting homeostasis, is a common feature across various neurological events, including ischemic, infectious, traumatic, and neurodegenerative conditions. Emerging research suggests that regulating autophagy may offer a promising therapeutic avenue for treating certain neurological diseases. Furthermore, existing literature indicates that various small molecule autophagy regulators have been tested in animal models and are linked to neurological disease outcomes. This review explores the role of mitophagy in programmed neuronal death and its connection to neuroinflammation. [ABSTRACT FROM AUTHOR]

Multiple myeloma (MM) is a highly heterogeneous hematological malignancy that is currently incurable. Individualized therapeutic approaches based on accurate risk assessment are essential for improving the prognosis of MM patients. Nevertheless, current prognostic models for MM exhibit certain limitations and prognosis heterogeneity still an unresolved issue. Recent studies have highlighted the pivotal involvement of mitochondrial autophagy in the development and drug sensitivity of MM. This study seeks to conduct an integrative analysis of the prognostic significance and immune microenvironment of mitophagy-related signature in MM, with the aim of constructing a novel predictive risk model. GSE4581 and GSE47552 datasets were acquired from the Gene Expression Omnibus database. MM-differentially expressed genes (DEGs) were identified by limma between MM samples and normal samples in GSE47552. Mitophagy key module genes were obtained by weighted gene co-expression network analysis in the Cancer Genome Atlas (TCGA)-MM dataset. Mitophagy DEGs were identified by the overlap genes between MM-DEGs and mitophagy key module genes. Prognostic genes were selected through univariate Cox regression and least absolute shrinkage and selection operator (LASSO) analysis, and a risk model was subsequently constructed based on these prognostic genes. Subsequently, the MM samples were stratified into high- and low-risk groups based on their median risk scores. The validity of the risk model was further evaluated using the GSE4581 dataset. Moreover, a nomogram was developed using the independent prognostic factors identified from the risk score and various clinical indicators. Additionally, analyses were conducted on immune infiltration, immune scores, immune checkpoint, and chemotherapy drug sensitivity. The 17 mitophagy DEGs were obtained by intersection of 803 MM-DEGs and 1084 mitophagy key module genes. Five prognostic genes (CDC6, PRIM1, SNRPB, TOP2A, and ZNF486) were selected via LASSO and univariate cox regression analyses. The predictive performance of the risk model, which was constructed based on the five prognostic genes, demonstrated favorable results in both TCGA-MM and GSE4581 datasets as indicated by the receiver operating characteristic (ROC) curves. In addition, calibration curve, ROC curve, and decision curve analysis curve corroborated that the nomogram exhibited superior predictive accuracy for MM. Furthermore, immune analysis results indicated a significant difference in stromal scores of two risk groups categorized on median risk scores. And four immune checkpoints (CD274, CTLA4, LAG3, and PDCD1LG2) showed significant differences in different risk groups. The analysis of chemotherapy drug sensitivity revealed that etoposide and doxorubicin, which target TOP2A, exhibited superior treatment outcomes in the high-risk group. A novel prognostic model for MM was developed and validated, demonstrating significant potential in predicting patient outcomes and providing valuable guidance for personalized immunotherapy counseling. [ABSTRACT FROM AUTHOR]

Background and Purpose Experimental approach Key Results Conclusions and Implications Dihydro‐resveratrol (DHR), a polyphenol derivative, that has been demonstrated to suppress inflammation‐mediated injury. However, it is still unknown whether it has anti‐neuroinflammatory and neuroprotective effects, and a therapeutic action in Alzheimer's disease (AD).The anti‐inflammatory and anti‐Alzheimer's disease actions of dihydro‐resveratrol were investigated using lipopolysaccharide (LPS) and AD mice models, and primary microglial cells. The changes in behaviour in mice were detected by the Morris water maze test and open‐field test. Flow cytometry assay, western blotting, immunofluorescence assays and co‐immunoprecipitation were used to investigate the changes in the NLRP3 inflammasome activation and mitophagy.In this study, in vivo observations indicated that the administration of dihydro‐resveratrol (DHR) dramatically restored spatial learning, memory ability, autophagy and mitophagy, attenuated NLRP3 inflammasome activation, neuroinflammation and amyloid precursor protein pathology in LPS mice and AD mice. In addition, the inhibition of autophagy and mitophagy, or the activation of NLRP3 in vivo greatly abolished DHR‐generated therapeutic efficacy on neuroinflammation, amyloid precursor protein pathology and cognitive loss. Further examination indicated that the application of DHR after the LPS and ATP exposure significantly inhibited the NLRP3 inflammasome activation, neuroinflammation and enhanced autophagic and mitophagic activation in microglia. Additionally, in vitro results show that DHR protects microglial cells against LPS and ATP‐induced cytotoxicity by inhibiting NLRP3 inflammasome through activating Bnip3‐dependent mitophagy and ULK phosphorylation.In summary, these findings suggest that dihydro‐resveratrol (DHR) possesses potent anti‐neuroinflammatory property and can act as a potential therapeutic agent for the treatment of AD. [ABSTRACT FROM AUTHOR]

In sepsis, inflammation, and nutrient deficiencies endanger cellular homeostasis and survival. Autophagy is primarily a mechanism of cellular survival under fasting conditions. However, autophagy-dependent cell death, known as autophagic cell death, is proinflammatory and can exacerbate sepsis. Autophagy also regulates various types of non-inflammatory and inflammatory cell deaths. Non-inflammatory apoptosis tends to suppress inflammation, however, inflammatory necroptosis, pyroptosis, ferroptosis, and autophagic cell death lead to the release of inflammatory cytokines and damage-associated molecular patterns (DAMPs) and amplify inflammation. The selection of cell death mechanisms is complex and often involves a mixture of various styles. Similarly, protective autophagy and lethal autophagy may be triggered simultaneously in cells. How cells balance the regulatory mechanisms of these processes is an area of interest that is still under investigation. Therapies aimed at modulating autophagy are considered promising. Enhancing autophagy helps clear and recycle damaged organelles and reduce the burden of inflammatory processes while inhibiting excessive autophagy, which could prevent autophagic cell death. In this review, we introduce recent advances in research and the complex regulatory system of autophagy in sepsis. [ABSTRACT FROM AUTHOR]

Cisplatin-based chemotherapy serves as the standard of care for individuals with advanced stages of gastric cancer. Nevertheless, the emergence of chemoresistance in GC has detrimental impacts on prognosis, yet the underlying mechanisms governing this phenomenon remain elusive. Level of mitophagy and ferroptosis of GC cells were detected by fluorescence, flow cytometry, GSH, MDA, Fe2+ assays, and to explore the specific molecular mechanisms between NPR1 and cisplatin resistance by performing western blot and coimmunoprecipitation (co-IP) assays. These results indicates that NPR1 positively correlated with cisplatin-resistance and played a crucial part in conferring resistance to cisplatin in gastric cancer cells. Mechanistically, NPR1 affected levels of mitophagy and ferroptosis in human cisplatin-resistance GC cells with cisplatin treatment. Specifically, NPR1 inhibited mitophagy-dependent ferroptosis by reducing the ubiquitination-mediated degradation of PARL; moreover, NPR1 promoted PARL stabilization by disrupting the PARL–MARCH8 complex, which ultimately led to the development of chemoresistance in GC cells. Considering our findings, NPR1 appears to play an important role in chemotherapy for GC. NPR1 could potentially be used to overcome chemotherapy resistance. 1. NPR1 is highly expressed in cisplatin-resistant GC cells and promotes the cisplatin resistance. 2. According to IP-MS, NPR1 inhibits mitophagy-dependent ferroptosis through its downstream protein PARL. 3. NPR1 promoted PARL stabilization by disrupting the PARL–MARCH8 complex to inhibit the ubiquitination-mediated degradation of PARL. [ABSTRACT FROM AUTHOR]

PurposeMethodsResultsConclusionPancreatic β-cells play a critical role in regulating plasma insulin levels and glucose metabolism balance, with their dysfunction being a key factor in the progression of diabetes. This review aims to explore the role of autophagy, a vital cellular self-maintenance process, in preserving pancreatic β-cell functionality and its implications in diabetes pathogenesis.We examine the current literature on the role of autophagy in β-cells, highlighting its function in maintaining cell structure, quantity, and function. The review also discusses the effects of both excessive and insufficient autophagy on β-cell dysfunction and glucose metabolism imbalance. Furthermore, we discuss potential therapeutic agents that modulate the autophagy pathway to influence β-cell function, providing insights into therapeutic strategies for diabetes management.Autophagy acts as a self-protective mechanism within pancreatic β-cells, clearing damaged organelles and proteins to maintain cellular stability. Abnormal autophagy activity, either overactive or deficient, can disrupt β-cell function and glucose regulation, contributing to diabetes progression.Autophagy plays a pivotal role in maintaining pancreatic β-cell function, and its dysregulation is implicated in the development of diabetes. Targeting the autophagy pathway offers potential therapeutic strategies for diabetes management, with agents that modulate autophagy showing promise in preserving β-cell function. [ABSTRACT FROM AUTHOR]

Background: Overconsumption of retinoic acid (RA) or its analogues/derivatives has been linked to severe craniomaxillofacial malformations, such as cleft palate and midface hypoplasia. It has been noted that RA disturbed the proliferation and migration of embryonic palatal mesenchymal (EPM) cells in these malformations, yet the exact mechanisms underlying these disruptions remained unclear. Methods: A model of retinoic acid (RA)-induced cleft palate in fetal mice was successfully established. Histological alterations in the palate were evaluated using Hematoxylin and Eosin (H&E) staining and RNA in situ hybridization (RNAscope). Cellular proliferation levels were quantified via the Cell Counting Kit-8 (CCK-8) assay and EdU incorporation assay, while cell migration capabilities were investigated using wound healing and Transwell assays. Mitochondrial functions were assessed through Mito-Tracker fluorescence, mitochondrial reactive oxygen species (ROS) measurement, ATP level quantification, and mitochondrial DNA (mtDNA) copy number analysis. Differential gene expression and associated signaling pathways were identified through bioinformatics analysis. Alterations in the transcriptional and translational levels of Lhx6 and genes associated with mitophagy were quantified using quantitative PCR (qPCR) and Western blot analysis, respectively. Mitochondrial morphology and the mitochondrial autophagosomes within cells were examined through transmission electron microscopy (TEM). Results: Abnormal palatal development in mice, along with impaired proliferation and migration of human embryonic palatal mesenchymal (HEPM) cells, was associated with RA affecting mitochondrial function and concomitant downregulation of Lhx6. Knockdown of Lhx6 in HEPM cells resulted in altered cell proliferation, migration, and mitochondrial function. Conversely, the aberrant mitochondrial function, proliferation, and migration observed in RA-induced HEPM cells were ameliorated by overexpression of Lhx6. Subsequent research demonstrated that Lhx6 ameliorated RA-induced dysfunction in HEPM cells by modulating PINK1/Parkin-mediated mitophagy, thereby activating the MAPK signaling pathways. Conclusion: Lhx6 is essential for mitochondrial homeostasis via tuning PINK1/Parkin-mediated mitophagy and MAPK signaling pathways. Downregulation of Lhx6 by RA transcriptionally disturbs the mitochondrial homeostasis, which in turn leads to the proliferation and migration defect in HEPM cells, ultimately causing the cleft palate. [ABSTRACT FROM AUTHOR]

As one of the most prevalent malignancies, lung cancer displays considerable biological variability in both molecular and clinical characteristics. Lung cancer is broadly categorized into small cell lung cancer (SCLC) and non-small cell lung cancer (NSCLC) with the latter being most prevalent. The primary histological subtypes of NSCLC are lung adenocarcinoma (LUAD) and lung squamous cell carcinoma (LUSC). In the present work, we primarily extracted mRNA count data from a publicly accessible database followed by differentially expressed genes (DEGs) and differentially expressed mitophagy-related genes (DEMRGs) identification in case of both LUAD and LUSC cohorts. Next, we identified important DEMRGs via clustering approach followed by enrichment, survival, and mutational analyses. Lastly, the finalized prognostic biomarker was validated using wet-lab experimentations. Primarily, we obtained 986 and 1714 DEGs across LUAD and LUSC cohorts. Only 7 DEMRGs from both cohorts had significant membership values as indicated by the clustering analysis. Most significant pathway, Gene Ontology (GO)-biological process (BP), GO-molecular function (MF), GO-cellular compartment (CC) terms were macroautophagy, GTP metabolic process, magnesium ion binding, mitochondrial outer membrane. Among all, only TDRKH reported significant overall survival (OS) and 14% amplification across LUAD patients. Lastly, we validated TDRKH via immunohistochemistry (IHC) and semi-quantitative polymerase chain reaction (PCR). In conclusion, our findings advocate for the exploration of TDRKH and their genetic alterations in precision oncology therapeutic approaches for LUAD, emphasizing the potential for target-driven therapy and early diagnostics. [ABSTRACT FROM AUTHOR]

Glaucoma is a leading cause of irreversible visual impairment worldwide, characterized by the progressive death of retinal ganglion cells (RGCs). Deubiquitinating enzyme (DUB) inhibitors have shown promise as pharmacological interventions for neurodegenerative disorders. Our study focuses on the pan-DUB inhibitor PR-619 and its potential neuroprotective effects on RGCs through modulation of parkin-mediated mitophagy in experimental glaucoma models. The results show that impaired mitophagy exists in RGCs of our experimental glaucomatous model. In vivo, PR-619 increased RGCs survival in glaucomatous rats. In vitro, it protected RGCs against excitotoxicity and reduced ubiquitin-specific protease (USP) 15 expression. Additionally, PR-619 upregulated parkin expression, increased LC3-II/LC3-I ratios, and elevated LAMP1 levels, indicating enhanced mitophagy in vivo and in vitro. Moreover, numbers of mitophagosomes were increased in optic nerves of PR-619-treated ocular hypertensive rats in vivo. Furthermore, parkin knockdown negated the salutary effects of PR-619 and attenuated expression of parkin-dependent mitophagy effectors in RGCs subjected to glutamate excitotoxicity in vitro. Collectively, these findings implicate augmented parkin-mediated mitophagy as the mechanistic substrate underscoring the neuroprotective capacity of PR-619 in experimental glaucoma. These revelations engender the prospect that pharmacological agents or biotherapeutics augmenting parkin-mediated mitophagy may proffer viable therapeutic modalities for glaucomatous neurodegeneration characterized by impaired mitophagy. [ABSTRACT FROM AUTHOR]

Intervertebral disc degeneration (IVDD) is a primary contributor to low back pain and poses a considerable burden to society. However, the molecular mechanisms underlying IVDD remain to be elucidated. PR/SET domain 1 (PRDM1) regulates cell proliferation, apoptosis, and inflammatory responses in various diseases. Despite these regulatory functions, the mechanism of action of PRDM1 in IVDD remains unexplored. In this study, we investigated the role and underlying mechanisms of action of PRDM1 in IVDD progression. The expression of PRDM1 in nucleus pulposus (NP) tissues and NP cells (NPCs) was assessed using western blotting, immunohistochemistry, and immunofluorescence. The effects of PRDM1 on IVDD progression were investigated in vitro and in vivo. Mechanistically, mRNA sequencing, chromatin immunoprecipitation, and dual-luciferase reporter assays were performed to confirm that PRDM1 triggered CASP1 transcription. Our study demonstrated for the first time that PRDM1 expression was substantially upregulated in degenerated NP tissues and NPCs. PRDM1 overexpression promoted NPCs pyroptosis by inhibiting mitophagy and exacerbating IVDD progression, whereas PRDM1 silencing exerted the opposite effect. Furthermore, PRDM1 activated CASP1 transcription, thereby promoting NPCs pyroptosis in vitro. Notably, CASP1 silencing reversed the effects of PRDM1 on the NPCs. To the best of our knowledge, this study is the first to demonstrate that PRDM1 silencing inhibits NPCs pyroptosis by repressing CASP1 transcription, which may be a promising new therapeutic target for IVDD. [ABSTRACT FROM AUTHOR]

Diabetic encephalopathy (DE) is a severe complication of diabetes, but its pathogenesis remains unclear. This study aimed to investigate the roles and underlying mechanisms of high glucose (HG)- and advanced glycosylation end product (AGE)-induced oxidative stress (OS) in the cognitive decline in DE. The DE mouse model was established using a high-fat diet and streptozotocin, and its cognitive functions were evaluated using the Morris Water Maze, novel object recognition, and Y-maze test. The results revealed increased reactive oxygen species (ROS) generation, mitophagy inhibition, and decreased prohibitin 2 (PHB2) expression in the hippocampal neurons of DE mice and HG- or AGE-treated HT-22 cells. However, overexpression of PHB2 reduced ROS generation, reversed mitophagy inhibition, and improved mitochondrial function in the HG- or AGE-treated HT-22 cells and ameliorated cognitive decline, improved mitochondrial structural damage, and reversed mitophagy inhibition of hippocampal neurons in DE mice. Further analysis revealed that the Kelch-like ECH-associated protein 1 (Keap1)–nuclear factor erythroid 2-related factor 2 (Nrf2) pathway was involved in the HG- or AGE-mediated downregulation of PHB2 in HT-22 cells. These results demonstrate that HG- or AGE-induced OS inhibits the mitophagy of hippocampal neurons via the Keap1–Nrf2–PHB2 pathway, thereby contributing to the cognitive decline in DE. [ABSTRACT FROM AUTHOR]

Apolipoprotein-L1 (APOL1) is a membrane-interacting protein induced by inflammation, which confers human resistance to infection by African trypanosomes. APOL1 kills Trypanosoma brucei through induction of apoptotic-like parasite death, but two T. brucei clones acquired resistance to APOL1, allowing them to cause sleeping sickness. An APOL1 C-terminal sequence alteration, such as occurs in natural West African variants G1 and G2, restored human resistance to these clones. However, APOL1 unfolding induced by G1 or G2 mutations enhances protein hydrophobicity, resulting in kidney podocyte dysfunctions affecting renal filtration. The mechanism involved in these dysfunctions is debated. The ability of APOL1 to generate ion pores in trypanosome intracellular membranes or in synthetic membranes was provided as an explanation. However, transmembrane insertion of APOL1 strictly depends on acidic conditions, and podocyte cytopathology mainly results from secreted APOL1 activity on the plasma membrane, which occurs under non-acidic conditions. In this review, I argue that besides inactivation of APOL3 functions in membrane dynamics (fission and fusion), APOL1 variants induce inflammation-linked podocyte toxicity not through pore formation, but through plasma membrane disturbance resulting from increased interaction with cholesterol, which enhances cation channels activity. A natural mutation in the membrane-interacting domain (N264K) abrogates variant APOL1 toxicity at the expense of slightly increased sensitivity to trypanosomes, further illustrating the continuous mutual adaptation between host and parasite. [ABSTRACT FROM AUTHOR]

Simple Summary: Under heat stress, the aerobic metabolic activity of the body is significantly accelerated, which easily leads to hypoxia of high-oxygen consumption tissues, such as the mammary gland. In dairy cattle growing in the high-temperature and high-humidity environment in Guangxi, especially those in the peak period of lactation with strong metabolism, the lack of oxygen in the mammary cells is more obvious, and the milk volume and composition are greatly affected, and even lead to metabolic disorders. Nitidine chloride (NC) is a natural alkaloid with antioxidant properties that can remove excess reactive oxygen species (ROS). However, there is limited information on the effect of NC on BMECs hypoxic injury and its molecular mechanism. In this study, molecular biological methods combined with non-targeted metabolomics were used to study the protective effect of NC on BMECs induced by hypoxic stress. Based on the results obtained, we found that NC has a protective effect on hypoxic mitochondria and regulates amino acid metabolism in response to hypoxic stress. Hypoxia in the mammary gland epithelial cells of milk buffalo (BMECs) can affect milk yield and composition, and it can even cause metabolic diseases. Nitidine chloride (NC) is a natural alkaloid with antioxidant properties that can scavenge excessive reactive oxygen species (ROS). However, the effect of NC on the hypoxic injury of BMECs and its molecular mechanisms are still unknown. Here, an immunofluorescence assay, transmission electron microscopy (TEM), and flow cytometry, combined with untargeted metabolomics, were used to investigate the protective effect of NC on hypoxic stress injury in BMECs. It was found that NC can significantly reduce cell activity (p < 0.05) and inhibit cellular oxidative stress (p < 0.05) and cell apoptosis (p < 0.05). A significant decrease in mitophagy mediated by the PINK1-Parkin pathway was observed after NC pretreatment (p < 0.05). In addition, a metabolic pathway enrichment analysis demonstrated that the mechanisms of NC against hypoxic stress may be related to the downregulation of pathways involving aminoacyl tRNA biosynthesis; arginine and proline metabolism; glycine, serine, and threonine metabolism; phenylalanine, tyrosine, and tryptophan biosynthesis; and phenylalanine metabolism. Thus, NC has a protective effect on hypoxic mitochondria, and it can regulate amino acid metabolism in response to hypoxic stress. The present study provides a reference for the application of nitidine chloride to regulate the mammary lactation function of milk buffalo. [ABSTRACT FROM AUTHOR]

Dysfunctional mitochondria producing excessive ROS are the main factors that cause ovarian aging. Immp2l deficiency causes mitochondrial dysfunction and excessive ROS production, leading to ovarian aging, which is attributed to granulosa cell senescence. The pathway controlling mitochondrial proteostasis and mitochondrial homeostasis of the UPRmt and mitophagy are closely related with the ROS and cell senescence. Our results suggest that Immp2l knockout led to granulosa cell senescence, and enocyanin treatment alleviated Immp2l deficiency-induced granulosa cell senescence, which was accompanied by improvements in mitochondrial function and reduced ROS levels. Interestingly, redox-related protein modifications, including S-glutathionylation and S-nitrosylation, were markedly increased in Immp2l-knockout granulosa cells, and were markedly reduced by enocyanin treatment. Furthermore, STAT1 was significantly increased in Immp2l-knockout granulosa cells and reduced by enocyanin treatment. The co-IP results suggest that the expression of STAT1 was controlled by S-glutathionylation and S-nitrosylation, but not phosphorylation. The UPRmt was impaired in Immp2l-deficient granulosa cells, and unfolded and misfolded proteins aggregated in mitochondria. Then, the HIF1α/BNIP3-mediated mitophagy pathway was activated, but mitophagy was impaired due to the reduced fusion of mitophagosomes and lysosomes. The excessive aggregation of mitochondria increased ROS production, leading to senescence. Hence, Enocyanin treatment alleviated granulosa cell senescence through STAT1/ATF4-mediated UPRmt and STAT1/(ATF4)/HIF1α/BNIP3-mediated mitophagy. [ABSTRACT FROM AUTHOR]

Percutaneous coronary intervention (PCI) combined with stent implantation is currently one of the most effective treatments for coronary artery disease (CAD). However, in-stent restenosis (ISR) significantly compromises its long-term efficacy. Mitophagy plays a crucial role in vascular homeostasis, yet its role in ISR remains unclear. This study aims to identify mitophagy-related biomarkers for ISR and explore their underlying molecular mechanisms. Through differential gene expression analysis between ISR and Control samples in the combined dataset, 169 differentially expressed genes (DEGs) were identified. Twenty-three differentially expressed mitophagy-related genes (DEMRGs) were identified by intersecting with mitophagy-related genes (MRGs) from the GeneCards, and functional enrichment analysis indicated their significant involvement in mitophagy-related biological processes. Using Weighted Gene Co-expression Network Analysis (WGCNA) and three machine learning algorithms (Logistic-LASSO, RF, and SVM-RFE), LRRK2, and ANKRD13A were identified as mitophagy-related biomarkers for ISR. The nomogram based on these two genes also exhibited promising diagnostic performance for ISR. Gene Set Enrichment Analysis (GSEA) as well as immune infiltration analyses showed that these two genes were closely associated with immune and inflammatory responses in ISR. Furthermore, potential small molecule compounds with therapeutic implications for ISR were predicted using the connectivity Map (cMAP) database. This study systematically investigated mitophagy-related biomarkers for ISR and their potential biological functions, providing new insights into early diagnosis and precision treatment strategies for ISR. [ABSTRACT FROM AUTHOR]

The NLR family pyrin domain containing 3 (NLRP3) inflammasome in microglia is intimately linked to the pathogenesis of Alzheimer's disease (AD). Although NLRP3 inflammasome activity is regulated by cellular metabolism, the underlying mechanism remains elusive. Here, we found that under the pathological conditions of AD, the activation of NLRP3 inflammasome in microglia is accompanied by increased glutamine metabolism. Suppression of glutaminase, the rate limiting enzyme in glutamine metabolism, attenuated the NLRP3 inflammasome activation both in the microglia of AD mice and cultured inflammatory microglia. Mechanistically, inhibiting glutaminase blocked the anaplerotic flux of glutamine to the tricarboxylic acid cycle and amino acid synthesis, down-regulated mTORC1 signaling by phosphorylating AMPK, which stimulated mitophagy and limited the accumulation of intracellular reactive oxygen species, ultimately prevented the activation of NLRP3 inflammasomes in activated microglia during AD. Taken together, our findings suggest that glutamine metabolism regulates the activation of NLRP3 inflammasome through mitophagy in microglia, thus providing a potential therapeutic target for AD treatment. [ABSTRACT FROM AUTHOR]

Background and Purpose: Mitochondrial dysfunction contributes to the pathogenesis and maintenance of chemotherapy‐induced peripheral neuropathy (CIPN), a significant limitation of cancer chemotherapy. Recently, the stimulation of mitophagy, a pivotal process for mitochondrial homeostasis, has emerged as a promising treatment strategy for neurodegenerative diseases, but its therapeutic effect on CIPN has not been explored. Here, we assessed the mitophagy‐inducing activity of 3,5‐dibromo‐2‐(2′,4′‐dibromophenoxy)‐phenol (PDE701), a diphenyl ether derivative isolated from the marine sponge Dysidea sp., and investigated its therapeutic effect on a CIPN model. Experimental Approach: Mitophagy activity was determined by a previously established mitophagy assay using mitochondrial Keima (mt‐Keima). Mitophagy induction was further verified by western blotting, immunofluorescence, and electron microscopy. Mitochondrial dysfunction was analysed by measuring mitochondrial superoxide levels in SH‐SY5Y cells and Drosophila larvae. A thermal nociception assay was used to evaluate the therapeutic effect of PDE701 on the paclitaxel‐induced thermal hyperalgesia phenotype in Drosophila larvae. Key Results: PDE701 specifically induced mitophagy but was not toxic to mitochondria. PDE701 ameliorated paclitaxel‐induced mitochondrial dysfunction in both SH‐SY5Y cells and Drosophila larvae. Importantly, PDE701 also significantly ameliorated paclitaxel‐induced thermal hyperalgesia in Drosophila larvae. Knockdown of ATG5 or ATG7 abolished the effect of PDE701 on thermal hyperalgesia, suggesting that PDE701 exerts its therapeutic effect through mitophagy induction. Conclusion and Implications: This study identified PDE701 as a novel mitophagy inducer and a potential therapeutic compound for CIPN. Our results suggest that mitophagy stimulation is a promising strategy for the treatment of CIPN and that marine organisms are a potential source of mitophagy‐inducing compounds. [ABSTRACT FROM AUTHOR]

Synaptic damage is a crucial pathological process in traumatic brain injury. However, the mechanisms driving this process remain poorly understood. In this report, we demonstrate that the accumulation of damaged mitochondria, resulting from impaired mitphagy, plays a significant role in causing synaptic damage. Moreover, copper induced downregulation of BNIP3 is a key player in regulating mitophagy. DMSA alleviates synaptic damage and mitochondrial dysfunction by promoting urinary excretion of copper. Mechanistically, we find that copper downregulate BNIP3 by increasing the nuclear translocation of NFKB, which is triggered by TRIM25-mediated ubiquitination-dependent degradation of NFKBIA. Our study underscores the importance of copper accumulation in the regulation of BNIP3-mediated mitophagy and suggests that therapeutic targeting of the copper-TRIM25-NFKB-BNIP3 axis holds promise to attenuate synaptic damage after traumatic brain injury. [ABSTRACT FROM AUTHOR]

Abstract\nKey pointsBackground: Diabetes patients’ quality of life can be severely impacted by diabetic muscle atrophy.Aim: This study aimed to explore the impact of high-intensity exercise (HIE) alongside insulin treatment on muscle atrophy in a rat model of type 1 diabetes mellitus (T1DM).Methodology: Fifty rats were allocated into five groups; Group 1, control sedentary (CS), T1DM was elicited in the rest of the groups by giving them Streptozotocin (STZ) (60 mg/kg), where group 2 (DS) remained sedentary, while groups 3,4,5 were treated with insulin after induction of diabetes. Group 4 (DI+MIE) and 5 (DI+ HIE) underwent moderate and high-intensity exercise, respectively.Results: HIE for 14 days combined with insulin treatment significantly restored muscle strength and mass with a significant modification in the mitophagy-related proteins and fibroblast growth factor 21 (FGF 21) compared to other treated groups.Conclusion: This study concluded that there is a therapeutic role for HIE with insulin against T1DM-induced muscle atrophy.T1DM induces loss of skeletal muscle mass and strength.T1DM enhances muscle atrophy-related genes (MAFbx and MuRF1) and impairs mitochondrial function.HIE alongside insulin treatment restores muscle mass, strength, and histological architecture in T1DM-induced muscle atrophy model.HIE alongside insulin treatment over MIE moderated the mitochondrial dysfunction via modulation of the mitophagy-related mediators (BNIP3, Parkin, P62, and LC3II/LC3I) and FGF 21 expression.T1DM induces loss of skeletal muscle mass and strength.T1DM enhances muscle atrophy-related genes (MAFbx and MuRF1) and impairs mitochondrial function.HIE alongside insulin treatment restores muscle mass, strength, and histological architecture in T1DM-induced muscle atrophy model.HIE alongside insulin treatment over MIE moderated the mitochondrial dysfunction via modulation of the mitophagy-related mediators (BNIP3, Parkin, P62, and LC3II/LC3I) and FGF 21 expression. [ABSTRACT FROM AUTHOR]

The influence of thyroid hormone (TH) on liver metabolism has attracted the attention of pharmacologists seeking new treatments for metabolic dysfunction-associated steatotic liver disease (MASLD), an increasingly common metabolic disorder. In this context, the selective induction of autophagy by TH in preclinical models has been identified as a promising mechanism. In this process, TH clears intrahepatic fat through lipophagy while protecting against inflammation and mitochondrial damage in hepatocytes via mitophagy. Furthermore, TH-induced aggrephagy may represent a protective mechanism to mitigate the development of MASLD-associated hepatocellular carcinoma. Considering the defects in autophagy observed during the progression of human MASLD, the induction of autophagy by TH, its metabolites, and its analogs represent a novel strategy to combat hepatic damage across the MASLD spectrum. [ABSTRACT FROM AUTHOR]

Background: Altered mitophagy has been observed in various neurological disorders, such as epilepsy. The role of mitophagy in causing neuronal damage during epileptic episodes is significant, and recent research has indicated that GLS2 plays a crucial role in regulating autophagy. However, exactly how GLS2 affects epilepsy is still unclear. Aims: To investigate the expression and distribution characteristics of GLS2 in epilepsy, and then observed the changes in behavior and electrophysiology caused by overexpression of GLS2 in epileptic mice, and determined whether GLS2 regulated seizure‐like changes in the mouse model through the protective mechanism of mitophagy. Results: The expression of GLS2 in a kainic acid (KA)‐induced epileptic mouse model and aglutamate‐inducedneuronal excitatory damage in HT22 cells model was downregulation. In brief, overexpression of GLS2 can alleviate epileptic activity. Subsequently, we demonstrated that GLS2 interacts with mitophagy‐related proteins in a KA‐induced epilepsy mouse model. Mechanistically, overexpression of GLS2 inhibited mitophagy in epileptic mice, downregulating the expression of LC3 and reducing ROS production. Conclusions: This study proves the GLS2 expression pattern is abnormal in epileptic mice. The function of mitophagy in hippocampal neurons is affected by GLS2, and overexpression of GLS2 can reduce the occurrence of seizure‐like events (SLEs) by altering mitophagy function. Thus, GLS2 might control seizures, and our findings provide a fresh avenue for antiepileptic treatment and offer novel insights into treating and preventing epilepsy. [ABSTRACT FROM AUTHOR]

Mitophagy, a selective form of autophagy, plays a crucial role in maintaining optimal mitochondrial populations, normal function, and intracellular homeostasis by monitoring and removing damaged or excess mitochondria. Furthermore, mitophagy promotes mitochondrial degradation via the lysosomal pathway, and not only eliminates damaged mitochondria but also regulates programmed cell death-associated genes, thus preventing cell death. The interaction between mitophagy and various forms of cell death has recently gained increasing attention in relation to the pathogenesis of clinical diseases, such as cancers and osteoarthritis, neurodegenerative, cardiovascular, and renal diseases. However, despite the abundant literature on this subject, there is a lack of understanding regarding the interaction between mitophagy and cell death. In this review, we discuss the main pathways of mitophagy, those related to cell death mechanisms (including apoptosis, ferroptosis, and pyroptosis), and the relationship between mitophagy and cell death uncovered in recent years. Our study offers potential directions for therapeutic intervention and disease diagnosis, and contributes to understanding the molecular mechanism of mitophagy. [ABSTRACT FROM AUTHOR]

Pseudorabies virus (PRV) utilizes multiple strategies to inhibit type I interferon (IFN-I) production and signaling to achieve innate immune evasion. Among several other functions, mitochondria serve as a crucial immune hub in the initiation of innate antiviral responses. It is currently unknown whether PRV inhibits innate immune responses by manipulating mitochondria. In this study, we found that PRV infection damages mitochondrial structure and function, as shown by mitochondrial membrane potential depolarization, reduction in mitochondrial numbers, and an imbalance in mitochondrial dynamics. In addition, PRV infection triggered PINK1-Parkin-mediated mitophagy to eliminate the impaired mitochondria, which resulted in a suppression of IFN-I production, thereby promoting viral replication. Furthermore, we found that mitophagy resulted in the degradation of the mitochondrial antiviral signaling protein, which is located on the mitochondrial outer membrane. In conclusion, the data of the current study indicate that PRV-induced mitophagy represents a previously uncharacterized PRV evasion mechanism of the IFN-I response, thereby promoting virus replication. [ABSTRACT FROM AUTHOR]

Simple Summary: Cancer chemotherapy is dominated by cytotoxic drugs that non-selectively kill proliferating cells by blocking DNA replication and inducing apoptosis. Some natural anticancer products are less toxic to normal, slow-replicating cells but kill aggressive tumor cells. The combination of two structural isomers of pentacyclic triterpenes, oleanolic acid and ursolic acid, showed potent cytotoxic activity in human breast cancer cells in vitro by inducing cytotoxic autophagy at a significantly lower dose than previously reported. They were nontoxic to breast epithelial cells. Their activity was mainly due to the inhibition of AKT-mediated cell survival and the inhibition of the mammalian target of rapamycin (mTOR) signaling pathway, a central regulator of cell metabolism, growth, and proliferation. The compounds were equally effective against ER+ and triple-negative breast cancer cells. Combining low doses of nontoxic inhibitors of PI3k kinase increased the activities of these compounds. In contrast, inhibition of autophagy by 3-methyl adenine annulled their activity, demonstrating that cytotoxic autophagy may be the dominant mechanism of cell death. These compounds have potential for cancer therapy in neoadjuvant or adjuvant settings. Background: Oleanolic acid (OA) and Ursolic acid (UA) are bioactive triterpenoids. Reported activities vary with the dose used for testing their activities in vitro. Studies using doses of ≥20 µM showed apoptosis activities in cancer cells. However, reported drug levels in circulation achieved by oral administration of UA and OA are ≤2 µM, thus limiting their use for treatment or delivering a combination treatment. Materials and Methods: The present report demonstrates the efficacy of OA, UA, and OA + UA on tumor cell-specific cytotoxicity at low doses (5 µM to 10 µM) in breast cancer (BrCa) cell lines MCF7 and MDA-MB231. Results: The data show that both OA and UA killed BrCa cells at low doses, but were significantly less toxic to MCF-12A, a non-tumorigenic cell line. Moreover, OA + UA at ≤10 µM was lethal to BrCa cells. Mechanistic studies unraveled the significant absence of apoptosis, but their cytotoxicity was due to the induction of excessive autophagy at a OA + UA dose of 5 µM each. A link to drug-induced cytotoxic autophagy was established by demonstrating a lack of their cytotoxicity by silencing the autophagy-targeting genes (ATGs), which prevented OA-, UA-, or OA + UA-induced cell death. Further, UA or OA + UA treatment of BrCa cells caused an inhibition of PI3 kinase-mediated phosphorylation of Akt/mTOR, the key pathways that regulate cancer cell survival, metabolism, and proliferation. Discussion: Combinations of a PI3K inhibitor (LY294002) with OA, UA, or OA + UA synergistically inhibited BrCa cell survival. Therefore, the dominance of cytotoxic autophagy by inhibiting PI3K-mediated autophagy may be the primary mechanism of PTT-induced anticancer activity in BrCa cells. Conclusion: These results suggest it would be worthwhile testing combined OA and UA in clinical settings. [ABSTRACT FROM AUTHOR]

Objective To investigate the mechanism of fisetin inhibiting the activation of microglia NOD-like receptor family protein 3 (NLRP3) inflammasome in microglia and alleviating cognitive impairment after sepsis. Methods C57BL/6 mice were used to establish the sepsis model by cecal ligation and puncture. Mice were divided into four groups: the sham group, the sepsis group, the sepsis+caspase-1 knockout group (sepsis+Cas-1-/- group) and the sepsis+fisetin group. Evans blue was used to detect the permeability of blood-brain barrier (BBB). Morris water maze was used to evaluate the cognitive function of mice. Western blot assay and immunofluorescence double staining were used to detect the expression of NLRP3 inflammasome-related proteins including caspase-1, N-terminal fragment of the GSDMD (GSDMD-N), interleukin (IL)-1β, IL-18 and mitophagy-related proteins (Pink1, Parkin and LC3-Ⅱ) in brain tissue and microglia. Results Compared with the sham group, expression levels of caspase-1, GSDMD-N, IL-1β and IL-18 were significantly increased in the sepsis group (P＜0.05). Compared with the sepsis group, expression levels of caspase-1, GSDMD-N, IL-1β and IL-18 were significantly decreased in the sepsis+Cas-1-/- group (P＜0.05). The expression levels of Pink1, Parkin and LC3- Ⅱ were significantly higher in the sepsis+fisetin group than those of the sepsis group (P＜0.05), and expression levels of caspase-1, GSDMD-N, IL-1β and IL-18 were significantly lower (P＜0.05). After fisetin intervention, the permeability of BBB was decreased and the cognitive impairment (decreased escape latency and increased frequencies of crossing the platform) was alleviated in the sepsis+fisetin group compared with those of the sepsis group (P＜0.05). Conclusion Fisetin may alleviate central inflammation and cognitive impairment after sepsis by inhibiting the activation of microglial NLRP3 inflammasome through activating mitophagy. [ABSTRACT FROM AUTHOR]

The list of standard abbreviations for JDS is available at adsa.org/jds-abbreviations-24. Nonstandard abbreviations are available in the Notes. Mitochondrial dysfunction has been reported to occur in the mammary gland of dairy cows suffering from ketosis. Prohibitin 2 (PHB2) plays a crucial role in regulating mitophagy, which clears impaired mitochondria to maintain normal mitochondrial function. Therefore, the current study aimed to investigate how PHB2 mediates mitophagy, thereby influencing mitochondrial function in the immortalized bovine mammary epithelial cell line (MAC-T cells). First, mammary gland tissue and blood samples were collected from healthy cows (n = 15, BHB <0.6 m M) and cows with clinical ketosis (n = 15, BHB >3.0 m M). Compared with healthy cows, cows with clinical ketosis exhibited lower DMI, milk production, milk protein, milk lactose, and serum glucose. In contrast, milk fat, serum nonesterified fatty acids (NEFA) and BHB were greater in cows with clinical ketosis. The protein abundance of PHB2, peroxisome proliferator activated receptor-γ coactivator-1α (PGC-1α), mitofusin 2 (MFN2) in whole cell lysates (WCL), as well as PHB2, sequestosome-1 (SQSTM1, also called p62), microtubule-associated protein 1 light chain 3-II (MAP1LC3-II, also called LC3-II), and ubiquitinated proteins in mitochondrial fraction were significantly lower in cows with clinical ketosis. The ATP content of mammary gland tissue in cows with clinical ketosis was lower than that of healthy cows. Second, MAC-T were cultured and treated with NEFA (0, 0.3, 0.6, 1.2 m M). The MAC-T treated with 1.2 m M NEFA displayed decreased protein abundance of PHB2, PGC-1α, and MFN2 in WCL, as well as protein abundance of PHB2, p62, LC3-II, and ubiquitinated proteins in mitochondrial fraction. The content of ATP and JC-1 aggregates in 1.2 m M NEFA group were lower than in the 0 m M NEFA group. Additionally, 1.2 m M NEFA disrupted the fusion between mitochondria and lysosomes. The MAC-T were then pretreated with 100 n M rapamycin, followed by treatment with or without NEFA. Rapamycin alleviated impaired mitophagy and mitochondria dysfunction induced by 1.2 m M NEFA. Third, MAC-T were transfected with small interfering RNA to silence PHB2 or a plasmid for overexpression of PHB2, followed by treatment with or without NEFA. The silencing of PHB2 aggravated 1.2 m M NEFA-induced impaired mitophagy and mitochondrial dysfunction, whereas the overexpression of PHB2 alleviated these effects. Overall, this study provides evidence that PHB2, in regulation of mitophagy, is a mechanism for bovine mammary epithelial cells to counteract NEFA-induced mitochondrial dysfunction. [ABSTRACT FROM AUTHOR]

Chlorosis in azaleas is characterized by an interveinal yellowing of leaves that is typically caused by a deficiency of iron. This condition is usually due to the inability of cells to properly acquire iron as a consequence of unfavorable conditions, such as an elevated pH, rather than insufficient iron levels. The causes and effects of chlorosis were found to have similarities with those pertaining to a recently presented hypothesis that describes a pathogenic process in Alzheimer disease. This hypothesis states that iron becomes sequestered (e.g., by amyloid β and tau), causing a functional deficiency of iron that disrupts biochemical processes leading to neurodegeneration. Additional mechanisms that contribute to iron becoming unavailable include iron-containing structures not undergoing proper recycling (e.g., disrupted mitophagy and altered ferritinophagy) and failure to successfully translocate iron from one compartment to another (e.g., due to impaired lysosomal acidification). Other contributors to a functional deficiency of iron in patients with Alzheimer disease include altered metabolism of heme or altered production of iron-containing proteins and their partners (e.g., subunits, upstream proteins). A review of the evidence supporting this hypothesis is presented. Also, parallels between the mechanisms underlying a functional iron-deficient state in Alzheimer disease and those occurring for chlorosis in plants are discussed. Finally, a model describing the generation of a functional iron deficiency in Alzheimer disease is put forward. [ABSTRACT FROM AUTHOR]

Increasing evidence underscores the pivotal role of ferroptosis in Parkinson's Disease (PD) pathogenesis. Acteoside (ACT) has been reported to possess neuroprotective properties. However, the effects of ACT on ferroptosis and its molecular mechanisms remain unknown. This study aimed to explore whether ACT can regulate ferroptosis in dopaminergic (DA) neurons within both in vitro and in vivo PD models and to elucidate the underlying regulatory mechanisms. PD models were established and treated with various concentrations of ACT. Cell viability assays, Western blot, lipid peroxidation assessments, immunohistochemistry, and transmission electron microscopy were employed to confirm ACT's inhibition of ferroptosis and its protective effect on DA neurons across PD models. Immunofluorescence staining, MitoSOX staining, and confocal laser scanning microscopy further validated ACT's regulation regulatory effects on ferroptosis via the Nrf2-mitophagy pathway. Four animal behavioral tests were used to assess behavioral improvements in PD animals. ACT inhibited ferroptosis in PD models in vitro , as evidenced by increased cell viability, the upregulation of GPX4 and SLC7A11, reduced lipid peroxides, and attenuation of mitochondrial morphological alterations typical of ferroptosis. By activating the Nrf2-mitophagy axis, ACT enhanced mitochondrial integrity and reduced lipid peroxidation, mitigating ferroptosis. These in vitro results were consistent with in vivo findings, where ACT treatment significantly preserved DA neurons, curbed ferroptosis in these cells, and alleviated cognitive and behavioral deficits. This study is the first demonstration of ACT's capability to inhibit neuronal ferroptosis and protect DA neurons, thus alleviating behavioral and cognitive impairments in both in vitro and in vivo PD models. Furthermore, The suppression of ferroptosis by ACT is achieved through the activation of the Nrf2-mitophagy signaling pathway. Our results show that ACT is beneficial for both treating and preventing PD. They also offer novel therapeutic options for treating PD and molecular targets for regulating ferroptosis. [Display omitted] • Acteoside exhibits neuroprotective effects in Parkinson's Disease (PD) models by inhibiting ferroptosis. • First demonstration of Acteoside inhibiting neuronal ferroptosis in vitro and in vivo PD models. • Acteoside enhances Nrf2-mediated mitophagy, reducing oxidative stress, which suppresses ferroptosis. • Acteoside treatment results in significant behavioral and cognitive improvements in MPTP-induced PD mouse models. [ABSTRACT FROM AUTHOR]

As an effective formula of traditional Chinese medicine, Yang-Gan-Jiang-Mei (YGJM) formula exhibited a unique advantage in ameliorating liver injury and hepatic steatosis of non-alcoholic steatohepatitis (NASH). Nevertheless, the related pharmacological mechanism needs to be elucidated. This study aimed to explore the molecular mechanism of YGJM formula on mitophagy mediated by PINK1/parkin signaling pathway and NOD-like receptor protein 3 (NLRP3) inflammasome in NASH. High-fat-diet rats and HepG2 cells induced by free fatty acid were used as NASH models in vivo and in vitro. Liver pathology and serum indicator embodying liver function (aspartate transferase, alanine transferase, triglyceride, and total cholesterol) were applied to evaluate the extent of hepatic damage and lipid accumulation. Besides, transmission electron microscopy, JC-1 and 2',7'-dichlorofluorescein diacetate were utilized to observe hepatic mitochondrial morphology, as well as cellular mitochondrial membrane potential and reactive oxygen species level. Additionally, expression of PINK1/parkin-mediated mitophagy and NLRP3 inflammasome was detected to elucidate the underlying mechanism of YGJM formula by immunohistochemistry, immunofluorescence, RT-PCR (reverse transcription-polymerase chain reaction) and Western blot. The manifestations of pathology and biochemical detection confirmed the efficacy of YGJM formula in relieving hepatic damage and lipid deposition. Simultaneously, YGJM formula could obviously improve mitochondrial function. In addition, YGJM formula exhibited the promotion of PINK1/parkin-mediated mitophagy, which could perturb NLRP3 inflammasome activation, and as a result, the hepatocyte inflammation was also suppressed both in vitro and in vivo. Our preliminary results indicate that YGJM formula can ameliorate NASH mechanistically by interfering with PINK1/parkin-mediated mitophagy and NLRP3 inflammasome to exert anti-inflammation ability and promote mitochondrial function restoration. [ABSTRACT FROM AUTHOR]

Arterial remodeling is a common pathophysiological change in the pathogenesis of cardiovascular diseases in which the phenotypic switch of vascular smooth muscle cells (VSMC) plays an important role. Recently, an increasing number of long non-coding RNAs(lncRNAs) have been shown to encode micropeptides that play biological roles and have great clinical transformation potential. However, the role of micropeptides encoded by lncRNAs in arterial remodeling has not been well studied and requires further exploration. Through bioinformatic analysis and experimental verification, we found that a new lncRNA, the mitochondrial function-related lncRNA (MFRL), encodes a 64-amino acid micropeptide, MFRLP. MFRL and MFRLP play important roles in the phenotypic switch of VSMC. Further experiments showed that MFRLP interacts with mitochondrial cytochrome b to reduce accumulation of reactive oxygen species, suppress mitophagy and inhibit the VSMC switch from contractile to synthetic phenotype. LncRNA MFRL encodes the micropeptide MFRLP, which interacts with mitochondrial cytochrome b to inhibit the VSMC switch from contractile to synthetic phenotype and improve arterial remodeling. [ABSTRACT FROM AUTHOR]

Hepatic ischemia reperfusion (I/R) injury is a common clinical complication. X-box binding protein 1 (XBP1), as a critical regulator of the endoplasmic reticulum stress, has been implicated in a variety of diseases. In this study, we aimed to investigate the effects and the underlying mechanism of XBP1 in the progression of hepatic I/R injury. Hepatocyte-specific XBP1 knockout mice, multiple viral delivery systems and specific pharmacological inhibitors were applied in vivo in a partial hepatic I/R injury mouse model and in vitro in a cell model of hypoxia-reoxygenation (H/R) injury. Mitophagy and autophagic flux were evaluated and fluorescence resonance energy transfer (FRET) as well as immunoprecipitation were performed. The results demonstrated that reperfusion for 6 h represented a critical timepoint in hepatic I/R injury and resulted in significant intracellular mitochondrial dysfunction; led to the breakdown of hepatocytes accompanied by the highest expression levels of XBP1. Hepatocyte-specific XBP1 knockout alleviated hepatic I/R injury via enhanced mitophagy, as demonstrated by the reduction in hepatocellular damage/necrosis and increased expression of mitophagy markers. Mechanistically, XBP1 interacted with FoxO1 directly and catalyzed the ubiquitination of FoxO1 for proteasomal degradation. Targeting XBP1 by genetic or pharmacological techniques potentiated the protein levels of FoxO1, further promoting the activity of the PINK1/Parkin signaling pathway, thus augmenting mitophagy and exerting hepatoprotective effects upon I/R injury. In conclusion, the inhibition of XBP1 potentiated FoxO1-mediated mitophagy in hepatic I/R injury. Specific genetic and pharmacological treatment targeting XBP1 in the perioperative 6 h prior to reperfusion exerted beneficial effects, thus providing a novel therapeutic approach. [ABSTRACT FROM AUTHOR]

The aim of this work was to investigate the therapeutic effect of modified Shisiwei Jianzhong Decoction (SJD) on aplastic anemia (AA) and its potential pharmacological mechanism from the perspective of mitophagy. A comprehensive approach combining network pharmacology, mendelian randomization, molecular docking and animal experiments was applied to evaluate the properties of SJD against AA. By integrating multiple databases, it was determined that SJD exerted its therapeutic effect on AA by targeting three key targets [mammalian target of rapamycin (MTOR), poly(ADP‐ribose) polymerase 1 (PARP1) and Sirtuin 1 (SIRT1)] through four core compounds (quercetin, resveratrol, genistein and curcumin). Mendelian randomization analysis identified MTOR as a risk factor for AA occurrence while PARP1 was a protective factor. Results of animal experiments showed that SJD improved peripheral blood counts and promoted the proliferation of hematopoietic stem cells. Mechanistically, SJD, especially at high dose, played a therapeutic role in AA by activating mitophagy‐related proteins PTEN induced kinase 1 (PINK1)/Parkin and inhibiting the phosphatidylinositol 3‐kinase (PI3K)/protein kinase (AKT)/MTOR pathway. This study revealed for the first time the core chemical composition of SJD and its pharmacological effects against AA, which can restore hematopoietic function by activating mitophagy. The results provide inspiration for the clinical application of traditional Chinese medicine in AA treatment. [ABSTRACT FROM AUTHOR]

Background: Mitochondrial dysfunction is an important factor in the pathogenesis of schizophrenia. However, the relationship between mitophagy and schizophrenia remains to be elucidated. Methods: Single-cell RNA sequencing datasets of peripheral blood and brain organoids from SCZ patients and healthy controls were retrieved. Mitophagy-related genes that were differentially expressed between the two groups were screened. The diagnostic model based on key mitophagy genes was constructed using two machine learning methods, and the relationship between mitophagy and immune cells was analyzed. Single-cell RNA sequencing data of brain organoids was used to calculate the mitophagy score (Mitoscore). Results: We found 7 key mitophagy genes to construct a diagnostic model. The mitophagy genes were related to the infiltration of neutrophils, activated dendritic cells, resting NK cells, regulatory T cells, resting memory T cells, and CD8 T cells. In addition, we identified 12 cell clusters based on the Mitoscore, and the most abundant neurons were further divided into three subgroups. Results at the single-cell level showed that Mitohigh_Neuron established a novel interaction with endothelial cells via SPP1 signaling pathway, suggesting their distinct roles in SCZ pathogenesis. Conclusion: We identified a mitophagy signature for schizophrenia that provides new insights into disease pathogenesis and new possibilities for its diagnosis and treatment. [ABSTRACT FROM AUTHOR]

Background: Myocardial ischemia-reperfusion injury (MI/RI) is an unavoidable risk event for acute myocardial infarction, with ferroptosis showing close involvement. We investigated the mechanism of MI/RI inducing myocardial injury by inhibiting the ferroptosis-related SLC7A11/glutathione (GSH)/glutathione peroxidase 4 (GPX4) pathway and activating mitophagy. Methods: A rat MI/RI model was established, with myocardial infarction area and injury assessed by TTC and H&E staining. Rat cardiomyocytes H9C2 were cultured in vitro, followed by hypoxia/reoxygenation (H/R) modeling and the ferroptosis inhibitor lipoxstatin-1 (Lip-1) treatment, or 3-Methyladenine or rapamycin treatment and overexpression plasmid (oe-SLC7A11) transfection during modeling. Cell viability and death were evaluated by CCK-8 and LDH assays. Mitochondrial morphology was observed by transmission electron microscopy. Mitochondrial membrane potential was detected by fluorescence dye JC-1. Levels of inflammatory factors, reactive oxygen species (ROS), Fe2+, malondialdehyde, lipid peroxidation, GPX4 enzyme activity, glutathione reductase, GSH and glutathione disulfide, and SLC7A11, GPX4, LC3II/I and p62 proteins were determined by ELISA kit, related indicator detection kits and Western blot. Results: The ferroptosis-related SLC7A11/GSH/GPX4 pathway was repressed in MI/RI rat myocardial tissues, inducing myocardial injury. H/R affected GSH synthesis and inhibited GPX4 enzyme activity by down-regulating SLC7A11, thus promoting ferroptosis in cardiomyocytes, which was averted by Lip-1. SLC7A11 overexpression improved H/R-induced cardiomyocyte ferroptosis via the GSH/GPX4 pathway. H/R activated mitophagy in cardiomyocytes. Mitophagy inhibition reversed H/R-induced cellular ferroptosis. Mitophagy activation partially averted SLC7A11 overexpression-improved H/R-induced cardiomyocyte ferroptosis. H/R suppressed the ferroptosis-related SLC7A11/GSH/GPX4 pathway by inducing mitophagy, leading to cardiomyocyte injury. Conclusions: Increased ROS under H/R conditions triggered cardiomyocyte injury by inducing mitophagy to suppress the ferroptosis-related SLC7A11/GSH/GPX4 signaling pathway activation. [ABSTRACT FROM AUTHOR]

Mitophagy, a specialised form of autophagy, selectively targeting damaged or dysfunctional mitochondria, and is crucial for maintaining cellular homeostasis and mitochondrial quality control. Dysregulation of mitophagy contributes to various pathological conditions, including cancer, neurodegenerative and cardiovascular diseases. This review presents a comprehensive analysis of the molecular mechanisms, regulatory pathways, and interplay with other cellular processes governing mitophagy, emphasizing its importance in physiological and pathological contexts. We explore the PINK1/Parkin-mediated and receptor-mediated mitophagy pathways, encompassing BNIP3/NIX, FUNDC1, and Bcl2-L-13. Additionally, we discuss post-translational modifications and cellular signalling pathways modulating mitophagy, as well as the connection between mitophagy and ageing, highlighting the decline in mitophagy efficiency and its impact on age-related pathologies. The review also investigates mitophagy's role in human diseases such as cancer, myocardial ischemia–reperfusion injury, Parkinson's, and Alzheimer's disease. We assess the potential of mitophagy-targeting therapeutic strategies, focusing on the development of dietary therapies, small molecules, drugs, and gene therapy approaches that modulate mitophagy levels and efficiency for treating these diseases and dysfunctions commonly observed in ageing individuals. In summary, this review offers an extensive overview of the molecular mechanisms and regulatory networks involved in mitophagy, its association with autophagy, and implications in human health and disease. By examining the potential of mitophagy-modulating therapies in disease and non-disease settings, we aim to inspire further research to develop innovative treatment strategies for various pathological conditions linked to mitochondrial dysfunction and to ageing. [ABSTRACT FROM AUTHOR]

Skeletal muscle plays a crucial role in generating force to facilitate movement. Skeletal muscle is a heterogenous tissue composed of diverse fibers with distinct contractile and metabolic profiles. The intricate classification of skeletal muscle fibers exists on a continuum ranging from type I (slow-twitch, oxidative) to type II (fast-twitch, glycolytic). The heterogenous distribution and characteristics of fibers within and between skeletal muscles profoundly influences cellular signaling; however, this has not been broadly discussed as it relates to macroautophagy/autophagy. The growing interest in skeletal muscle autophagy research underscores the necessity of comprehending the interplay between autophagic responses among skeletal muscles and fibers with different contractile properties, metabolic profiles, and other related signaling processes. We recommend approaching the interpretation of autophagy findings with careful consideration for two key reasons: 1) the distinct behaviors and responses of different skeletal muscles or fibers to various perturbations, and 2) the potential impact of alterations in skeletal muscle fiber type or metabolic profile on observed autophagic outcomes. This review provides an overview of the autophagic profile and response in skeletal muscles/fibers of different types and metabolic profiles. Further, this review discusses autophagic findings in various conditions and diseases that may differentially affect skeletal muscle. Finally, we provide key points of consideration to better enable researchers to fine-tune the design and interpretation of skeletal muscle autophagy experiments. Abbreviation: AKT1: AKT serine/threonine kinase 1; AMPK: AMP-activated protein kinase; ATG: autophagy related; ATG4: autophagy related 4 cysteine peptidase; ATG5: autophagy related 5; ATG7: autophagy related 7; ATG12: autophagy related 12; BECN1: beclin 1; BNIP3: BCL2 interacting protein 3; CKD: chronic kidney disease; COPD: chronic obstructive pulmonary disease; CS: citrate synthase; DIA: diaphragm; EDL: extensor digitorum longus; FOXO3/FOXO3A: forkhead box O3; GAS; gastrocnemius; GP: gastrocnemius-plantaris complex; MAP1LC3/LC3: microtubule associated protein 1 light chain 3; MAPK: mitogen-activated protein kinase; MYH: myosin heavy chain; PINK1: PTEN induced kinase 1; PLANT: plantaris; PRKN: parkin RBR E3 ubiquitin protein ligase; QUAD: quadriceps; RA: rectus abdominis; RG: red gastrocnemius; RQ: red quadriceps; SOL: soleus; SQSTM1: sequestosome 1; TA: tibialis anterior; WG: white gastrocnemius; WQ: white quadriceps; WVL: white vastus lateralis; VL: vastus lateralis; ULK1: unc-51 like autophagy activating kinase 1. [ABSTRACT FROM AUTHOR]

Mitochondria undergo fission and fusion, and their coordinated balance is crucial for maintaining mitochondrial homeostasis. In yeast, the dynamin-related protein Dnm1 is a mitochondrial fission factor acting from outside the mitochondria. We recently reported the mitochondrial intermembrane space protein Atg44/mitofissin/Mdi1/Mco8 as a novel fission factor, but the relationship between Atg44 and Dnm1 remains elusive. Here, we show that Atg44 is required to complete Dnm1-mediated mitochondrial fission under homeostatic conditions. Atg44-deficient cells often exhibit enlarged mitochondria with accumulated Dnm1 and rosary-like mitochondria with Dnm1 foci at constriction sites. These mitochondrial constriction sites retain the continuity of both the outer and inner membranes within an extremely confined space, indicating that Dnm1 is unable to complete mitochondrial fission without Atg44. Moreover, accumulated Atg44 proteins are observed at mitochondrial constriction sites. These findings suggest that Atg44 and Dnm1 cooperatively execute mitochondrial fission from inside and outside the mitochondria, respectively. Abbreviation: ATG: autophagy related; CLEM: correlative light and electron microscopy; EM: electron microscopy; ER: endoplasmic reticulum; ERMES: endoplasmic reticulum-mitochondria encounter structure; GA: glutaraldehyde; GFP: green fluorescent protein; GTP: guanosine triphosphate: IMM: inner mitochondrial membrane; IMS: intermembrane space; OMM: outer mitochondrial membrane; PB: phosphate buffer; PBS: phosphate-buffered saline; PFA: paraformaldehyde; RFP: red fluorescent protein; WT: wild type. [ABSTRACT FROM AUTHOR]