M133S mutation possibly involve in the ER stress and mitophagy pathway in maintenance hemodialysis patients with occult hepatitis B infection.

Occult hepatitis B virus infection (OBI) is characterized by the presence of HBV DNA in the absence of detectable HBsAg. OBI is an important risk factor for cirrhosis and hepatocellular carcinoma, but its pathogenesis has not been fully elucidated. Mutations in the HBV preS/S genes can lead to impaired secretion of either HBsAg or S-protein resulting in the accumulation of defective viruses or S protein in cells. In our previous work, the M133S mutation was present in the HBV S gene of maintenance hemodialysis (MHD) patients with OBI. In this study, we investigated the potential role of amino acid substitutions in S proteins in S protein production and secretion through the construction of mutant S gene plasmids, structural prediction, transcriptome sequencing analysis, and in vitro functional studies. Protein structure prediction showed that the S protein M133S mutant exhibited hydrophilic modifications, with greater aggregation and accumulation of the entire structure within the membrane phospholipid bilayer. Differential gene enrichment analysis of transcriptome sequencing data showed that differentially expressed genes were mainly concentrated in protein processing in the endoplasmic reticulum (ER). The expression of heat shock family proteins and ER chaperone molecules was significantly increased in the wild-type and mutant groups, whereas the expression of mitochondria-associated proteins was decreased. Immunofluorescence staining and protein blotting showed that the endoplasmic reticulum-associated protein PDI, the autophagy marker LC3, and the lysosome-associated protein LAMP2 co-localized with the S proteins in the wild-type and mutant strains, and their expression was increased. The mitochondria-associated TOMM20 protein was also co-expressed with the S protein, but expression was significantly reduced in the mutant. The M133S mutation in the S gene is expressed as a defective and misfolded protein that accumulates in the endoplasmic reticulum causing secretion-impaired endoplasmic reticulum stress, which in turn triggers mitochondrial autophagy and recruits lysosomes to fuse with the autophagosome, leading to mitochondrial clearance. This study preliminarily demonstrated that the mutation of M133S in the S gene can cause OBI and is associated with disease progression, providing a theoretical basis for the diagnosis and treatment of OBI.

SPRED2 Is a Novel Regulator of Autophagy in Hepatocellular Carcinoma Cells and Normal Hepatocytes.

Sprouty-related enabled/vasodilator-stimulated phosphoprotein homology 1 domain containing 2 (SPRED2) is an inhibitor of the mitogen-activated protein kinase (MAPK)/extracellular signal-regulated kinase (ERK) pathway and has been shown to promote autophagy in several cancers. Here, we aimed to determine whether SPRED2 plays a role in autophagy in hepatocellular carcinoma (HCC) cells. The Cancer Genome Atlas (TCGA) Liver Cancer Database showed a negative association between the level of SPRED2 and p62, a ubiquitin-binding scaffold protein that accumulates when autophagy is inhibited. Immunohistochemically, accumulation of p62 was detected in human HCC tissues with low SPRED2 expression. Overexpression of SPRED2 in HCC cells increased the number of autophagosomes and autophagic vacuoles containing damaged mitochondria, decreased p62 levels, and increased levels of light-chain-3 (LC3)-II, an autophagy marker. In contrast, SPRED2 deficiency increased p62 levels and decreased LC3-II levels. SPRED2 expression levels were negatively correlated with translocase of outer mitochondrial membrane 20 (TOM20) expression levels, suggesting its role in mitophagy. Mechanistically, SPRED2 overexpression reduced ERK activation followed by the mechanistic or mammalian target of rapamycin complex 1 (mTORC1)-mediated signaling pathway, and SPRED2 deficiency showed the opposite pattern. Finally, hepatic autophagy was impaired in the liver of SPRED2-deficient mice with hepatic lipid droplet accumulation in response to starvation. These results indicate that SPRED2 is a critical regulator of autophagy not only in HCC cells, but also in hepatocytes, and thus the manipulation of this process may provide new insights into liver pathology.

Activation of the Keap1/Nrf2 pathway suppresses mitochondrial dysfunction, oxidative stress, and motor phenotypes in C9orf72 ALS/FTD models.

Mitochondrial dysfunction is a common feature of C9orf72 amyotrophic lateral sclerosis/frontotemporal dementia (ALS/FTD); however, it remains unclear whether this is a cause or consequence of the pathogenic process. Analysing multiple aspects of mitochondrial biology across several Drosophila models of C9orf72-ALS/FTD, we found morphology, oxidative stress, and mitophagy are commonly affected, which correlated with progressive loss of locomotor performance. Notably, only genetic manipulations that reversed the oxidative stress levels were also able to rescue C9orf72 locomotor deficits, supporting a causative link between mitochondrial dysfunction, oxidative stress, and behavioural phenotypes. Targeting the key antioxidant Keap1/Nrf2 pathway, we found that genetic reduction of Keap1 or pharmacological inhibition by dimethyl fumarate significantly rescued the C9orf72-related oxidative stress and motor deficits. Finally, mitochondrial ROS levels were also elevated in C9orf72 patient-derived iNeurons and were effectively suppressed by dimethyl fumarate treatment. These results indicate that mitochondrial oxidative stress is an important mechanistic contributor to C9orf72 pathogenesis, affecting multiple aspects of mitochondrial function and turnover. Targeting the Keap1/Nrf2 signalling pathway to combat oxidative stress represents a therapeutic strategy for C9orf72-related ALS/FTD.

Identification of mitophagy and ferroptosis-related hub genes associated with intracerebral haemorrhage through bioinformatics analysis.

BACKGROUND: Mitophagy and ferroptosis occur in intracerebral haemorrhage (ICH) but our understanding of mitophagy and ferroptosis-related genes remains incomplete. AIM: This study aims to identify shared ICH genes for both processes. METHODS: ICH differentially expressed mitophagy and ferroptosis-related genes (DEMFRGs) were sourced from the GEO database and literature. Enrichment analysis elucidated functions. Hub genes were selected via STRING, MCODE, and MCC algorithms in Cytoscape. miRNAs targeting hubs were predicted using miRWalk 3.0, forming a miRNA-hub gene network. Immune microenvironment variances were assessed with MCP and TIMER. Potential small molecules for ICH were forecasted via CMap database. RESULTS: 64 DEMFRGs and ten hub genes potentially involved in various processes like ferroptosis, TNF signalling pathway, MAPK signalling pathway, and NF-kappa B signalling pathway were discovered. Several miRNAs were identified as shared targets of hub genes. The ICH group showed increased infiltration of monocytic lineage and myeloid dendritic cells compared to the Healthy group. Ten potential small molecule drugs (e.g. Zebularine, TWS-119, CG-930) were predicted via CMap. CONCLUSION: Several shared genes between mitophagy and ferroptosis potentially drive ICH progression via TNF, MAPK, and NF-kappa B pathways. These results offer valuable insights for further exploring the connection between mitophagy, ferroptosis, and ICH.

HOXD9 regulated mitophagy to promote endothelial progenitor cells angiogenesis and deep vein thrombosis recanalization and resolution.

BACKGROUND: Deep vein thrombosis (DVT) is a common vascular surgical disease caused by the coagulation of blood in the deep veins, and predominantly occur in the lower limbs. Endothelial progenitor cells (EPCs) are multi-functional stem cells, which are precursors of vascular endothelial cells. EPCs have gradually evolved into a promising treatment strategy for promoting deep vein thrombus dissolution and recanalization through the stimulation of various physical and chemical factors. METHODS: In this study, we utilized a mouse DVT model and performed several experiments including qRT-PCR, Western blot, tube formation, wound healing, Transwell assay, immunofluorescence, flow cytometry analysis, and immunoprecipitation to investigate the role of HOXD9 in the function of EPCs cells. The therapeutic effect of EPCs overexpressing HOXD9 on the DVT model and its mechanism were also explored. RESULTS: Overexpression of HOXD9 significantly enhanced the angiogenesis and migration abilities of EPCs, while inhibiting cell apoptosis. Additionally, results indicated that HOXD9 specifically targeted the HRD1 promoter region and regulated the downstream PINK1-mediated mitophagy. Interestingly, intravenous injection of EPCs overexpressing HOXD9 into mice promoted thrombus dissolution and recanalization, significantly decreasing venous thrombosis. CONCLUSIONS: The findings of this study reveal that HOXD9 plays a pivotal role in stimulating vascular formation in endothelial progenitor cells, indicating its potential as a therapeutic target for DVT management.

Identification of a Novel Five-Gene Prognostic Model for Laryngeal Cancer Associated with Mitophagy Using Integrated Bioinformatics Analysis and Experimental Verification.

Laryngeal cancer (LC) is a prevailing tumor with a high mortality rate. The pivotal role of mitophagy in LC is acknowledged; however, a comprehensive analysis of the corresponding genes has not been conducted. In the present study, we proposed a prognostic model consisting of mitophagy-related genes in LC. Clinical information and transcriptome profiling of patients with LC and mitophagy-related genes were retrieved from open-source databases. Gene set variation analysis (GSVA) and Weighted Gene Co-expression Network Analysis (WGCNA) were used to identify core mitophagy-related genes and construct gene co-expression networks. Functional enrichment analysis was employed to analyze the enriched regulatory pathways of the mitophagy-related genes. Kaplan-Meier curves (KM), Cox, and LASSO regression were applied to explore their prognostic effects. Finally, quantitative real-time PCR (RT-qPCR) further verified the bioinformatics prediction. A total of 45 genes related to mitochondrial pathways was collected. GSVA analysis demonstrated that these genes in tumor samples mainly referred to the mitochondrial pathway. Among these genes, five mitophagy-related-gene signatures (CERCAM, CHPF, EPHX3, EXT2, and MED15) were further identified to construct the prognostic model. KM and Cox regression analyses indicated that this model had an accurate prognostic prediction for LC. RT-qPCR showed that CERCAM, CHPF, EXT2, and MED15 expression were upregulated, and EPHX3 level was decreased in LC cells. The present study established a five-mitophagy-related-gene model that can predict the prognosis of LC patients, thus laying the foundation for a better understanding and potential advancements in clinical treatments for LC.

Multi omics analysis of mitophagy subtypes and integration of machine learning for predicting immunotherapy responses in head and neck squamous cell carcinoma.

Mitophagy serves as a critical mechanism for tumor cell death, significantly impacting the progression of tumors and their treatment approaches. There are significant challenges in treating patients with head and neck squamous cell carcinoma, underscoring the importance of identifying new targets for therapy. The function of mitophagy in head and neck squamous carcinoma remains uncertain, thus investigating its impact on patient outcomes and immunotherapeutic responses is especially crucial. We initially analyzed the differential expression, prognostic value, intergene correlations, copy number variations, and mutation frequencies of mitophagy-related genes at the pan-cancer level. Through unsupervised clustering, we divided head and neck squamous carcinoma into three subtypes with distinct prognoses, identified the signaling pathway features of each subtype using ssGSEA, and characterized subtype B as having features of an immune desert using various immune infiltration calculation methods. Using multi-omics data, we identified the genomic variation characteristics, mutated gene pathway features, and drug sensitivity features of the mitophagy subtypes. Utilizing a combination of 10 machine learning algorithms, we have developed a prognostic scoring model called Mitophagy Subgroup Risk Score (MSRS), which is used to predict patient survival and the response to immune checkpoint blockade therapy. Simultaneously, we applied MSRS to single-cell analysis to explore intercellular communication. Through laboratory experiments, we validated the biological function of SLC26A9, one of the genes in the risk model. In summary, we have explored the significant role of mitophagy in head and neck tumors through multi-omics data, providing new directions for clinical treatment.

MST1 knockdown inhibits osteoarthritis progression through Parkin-mediated mitophagy and Nrf2/NF-κB signalling pathway.

Osteoarthritis (OA) is a complicated disease that involves apoptosis and mitophagy. MST1 is a pro-apoptotic factor. Hence, decreasing its expression plays an anti-apoptotic effect. This study aims to investigate the protective effect of MST1 inhibition on OA and the underlying processes. Immunofluorescence (IF) was used to detect MST1 expression in cartilage tissue. Western Blot, ELISA and IF were used to analyse the expression of inflammation, extracellular matrix (ECM) degradation, apoptosis and mitophagy-associated proteins. MST1 expression in chondrocytes was inhibited using siRNA and shRNA in vitro and in vivo. Haematoxylin-Eosin, Safranin O-Fast Green and alcian blue staining were used to evaluate the therapeutic effect of inhibiting MST1. This study discovered that the expression of MST1 was higher in OA patients. Inhibition of MST1 reduced inflammation, ECM degradation and apoptosis and enhanced mitophagy in vitro. MST1 inhibition slows OA progression in vivo. Inhibiting MST1 suppressed apoptosis, inflammation and ECM degradation via promoting Parkin-mediated mitophagy and the Nrf2-NF-κB axis. The results suggest that MST1 is a possible therapeutic target for the treatment of osteoarthritis as its inhibition delays the progression of OA through the Nrf2-NF-κB axis and mitophagy.

Exploration of mitochondrial autophagy related genes in the diagnosis model construction and molecular marker mining of Alzheimer's disease based on multi-omics integration.

Key features of Alzheimer's disease include neuronal loss, accumulation of beta-amyloid plaques, and formation of neurofibrillary tangles. These changes are due in part to abnormal protein metabolism, particularly the accumulation of amyloid beta. Mitochondria are the energy production centers within cells and are also the main source of oxidative stress. In AD, mitochondrial function is impaired, leading to increased oxidative stress and the production of more reactive oxidative substances, further damaging cells. Mitophagy is an important mechanism for maintaining mitochondrial health, helping to clear damaged mitochondria, prevent the spread of oxidative stress, and reduce abnormal protein aggregation. To this end, this article conducts an integrated analysis based on DNA methylation and transcriptome data of AD. After taking the intersection of the genes where the differential methylation sites are located and the differential genes, machine learning methods were used to build an AD diagnostic model. This article screened five diagnostic genes ATG12, CSNK2A2, CSNK2B, MFN1 and PGAM5 and conducted experimental verification. The diagnostic genes discovered and the diagnostic model constructed in this article can provide reference for the development of clinical diagnostic models for AD.

Acupotomy alleviates knee osteoarthritis in rabbit by regulating chondrocyte mitophagy Pink1-Parkin pathway.

OBJECTIVE: To investigate the effect of acupotomy, on mitophagy and the Pink1-Parkin pathway in chondrocytes from rabbits with knee osteoarthritis (KOA). METHODS: A KOA model was established via the modified Videman method. Rabbits were randomly divided into a control group (CON), KOA group and KOA + acupotomy group (Acu). Rabbits in the acupotomy group were subjected to acupotomy for 4 weeks after model establishment. The behavior of the rabbits before and after intervention was recorded. Cartilage degeneration was evaluated by optical microscopy and fluorescence microscopy. The level of mitophagy was evaluated by transmission electron microscopy, immunofluorescence and enzyme-linked immunosorbent assay (ELISA). The expression of phosphatase and tensin homolog (PTEN)-induced kinase 1 (Pink1)-Parkin mitophagy pathway components was evaluated by immunofluorescence, Western blotting and real-time polymerase chain reaction. RESULTS: In rabbits with KOA, joint pain, mobility disorders and cartilage degeneration were observed, the Mankin score was increased, collagen type Ⅱ (Col-Ⅱ) expression was significantly decreased, mitophagy was inhibited, mitochondrial function was impaired, and factors associated with the Pink1-Parkin pathway were inhibited. Acupotomy regulated the expression of Pink1-Parkin pathway-related proteins, the mitophagy-related protein microtubule-associated protein-1 light chain-3, the translocase of the outer membrane, and the inner mitochondrial membrane 23; increased the colocalization of mitochondria and autophagosomes; promoted the removal of damaged mitochondria; restored mitochondrial adenosine-triphosphate (ATP) production; and alleviated cartilage degeneration in rabbits with KOA. CONCLUSIONS: Acupotomy played a role in alleviating KOA in rabbits by activating mitophagy in chondrocytes via the regulation of proteins that are related to the Pink1-Parkin pathway.

A new mutation in the Parkinson's-related FBXO7 gene impairs mitochondrial and proteasomal function.

Around 10% of Parkinson's disease (PD) cases are associated with mutations in various genes, including FBXO7, which encodes the substrate-recognition component for the Skp1-Cullin-F-box (SCF) class of ubiquitin E3 ligases that target proteins for proteasomal degradation. In their recent study, Al Rawi et al. characterized a new mutation in FBXO7, L250P, in a pediatric patient. Their findings reveal that the L250P mutation abolishes Fbxo7 interaction with the proteasome regulator, proteasome inhibitor 31kD (PI31), affecting proteasomal activity and the ubiquitination of some of the ligase's targets. Furthermore, the authors show that this previously undescribed mutation impairs mitochondrial function and mitophagy, emphasizing the importance of mitochondrial and proteasomal dysfunction in PD pathogenesis.

Apoptosis, Autophagy, and Mitophagy Genes in the CA3 Area in an Ischemic Model of Alzheimer's Disease with 2-Year Survival.

Background: Currently, no evidence exists on the expression of apoptosis (CASP3), autophagy (BECN1), and mitophagy (BNIP3) genes in the CA3 area after ischemia with long-term survival. Objective: The goal of the paper was to study changes in above genes expression in CA3 area after ischemia in the period of 6-24 months. Methods: In this study, using quantitative RT-PCR, we present the expression of genes associated with neuronal death in a rat ischemic model of Alzheimer's disease. Results: First time, we demonstrated overexpression of the CASP3 gene in CA3 area after ischemia with survival ranging from 0.5 to 2 years. Overexpression of the CASP3 gene was accompanied by a decrease in the activity level of the BECN1 and BNIP3 genes over a period of 0.5 year. Then, during 1-2 years, BNIP3 gene expression increased significantly and coincided with an increase in CASP3 gene expression. However, BECN1 gene expression was variable, increased significantly at 1 and 2 years and was below control values 1.5 years post-ischemia. Conclusions: Our observations suggest that ischemia with long-term survival induces neuronal death in CA3 through activation of caspase 3 in cooperation with the pro-apoptotic gene BNIP3. This study also suggests that the BNIP3 gene regulates caspase-independent pyramidal neuronal death post-ischemia. Thus, caspase-dependent and -independent death of neuronal cells occur post-ischemia in the CA3 area. Our data suggest new role of the BNIP3 gene in the regulation of post-ischemic neuronal death in CA3. This suggests the involvement of the BNIP3 together with the CASP3 in the CA3 in neuronal death post-ischemia.

PRKN-linked familial Parkinson's disease: cellular and molecular mechanisms of disease-linked variants.

Parkinson's disease (PD) is a common and incurable neurodegenerative disorder that arises from the loss of dopaminergic neurons in the substantia nigra and is mainly characterized by progressive loss of motor function. Monogenic familial PD is associated with highly penetrant variants in specific genes, notably the PRKN gene, where homozygous or compound heterozygous loss-of-function variants predominate. PRKN encodes Parkin, an E3 ubiquitin-protein ligase important for protein ubiquitination and mitophagy of damaged mitochondria. Accordingly, Parkin plays a central role in mitochondrial quality control but is itself also subject to a strict protein quality control system that rapidly eliminates certain disease-linked Parkin variants. Here, we summarize the cellular and molecular functions of Parkin, highlighting the various mechanisms by which PRKN gene variants result in loss-of-function. We emphasize the importance of high-throughput assays and computational tools for the clinical classification of PRKN gene variants and how detailed insights into the pathogenic mechanisms of PRKN gene variants may impact the development of personalized therapeutics.

Lipotoxic hepatocyte derived LIMA1 enriched small extracellular vesicles promote hepatic stellate cells activation via inhibiting mitophagy.

BACKGROUND: Hepatic stellate cells (HSCs) play a crucial role in the development of fibrosis in non-alcoholic fatty liver disease (NAFLD). Small extracellular vesicles (sEV) act as mediators for intercellular information transfer, delivering various fibrotic factors that impact the function of HSCs in liver fibrosis. In this study, we investigated the role of lipotoxic hepatocyte derived sEV (LTH-sEV) in HSCs activation and its intrinsic mechanisms. METHODS: High-fat diet (HFD) mice model was constructed to confirm the expression of LIMA1. The relationship between LIMA1-enriched LTH-sEV and LX2 activation was evaluated by measurement of fibrotic markers and related genes. Levels of mitophagy were detected using mt-keima lentivirus. The interaction between LIMA1 and PINK1 was discovered through database prediction and molecular docking. Finally, sEV was injected to investigate whether LIMA1 can accelerate HFD induced liver fibrosis in mice. RESULTS: LIMA1 expression was upregulated in lipotoxic hepatocytes and was found to be positively associated with the expression of the HSCs activation marker α-SMA. Lipotoxicity induced by OPA led to an increase in both the level of LIMA1 protein in LTH-sEV and the release of LTH-sEV. When HSCs were treated with LTH-sEV, LIMA1 was observed to hinder LX2 mitophagy while facilitating LX2 activation. Further investigation revealed that LIMA1 derived from LTH-sEV may inhibit PINK1-Parkin-mediated mitophagy, consequently promoting HSCs activation. Knocking down LIMA1 significantly attenuates the inhibitory effects of LTH-sEV on mitophagy and the promotion of HSCs activation. CONCLUSIONS: Lipotoxic hepatocyte-derived LIMA1-enriched sEVs play a crucial role in promoting HSCs activation in NAFLD-related liver fibrosis by negatively regulating PINK1 mediated mitophagy. These findings provide new insights into the pathological mechanisms involved in the development of fibrosis in NAFLD.

Impaired mitochondrial morphological plasticity and failure of mitophagy associated with the G11778A mutation of LHON.

Mitochondrial dynamics were examined in human dermal fibroblasts biopsied from a confirmed Leber's Hereditary Optic Neuropathy (LHON) patient with a homoplasmic G11778A mutation of the mitochondrial genome. Expression of the G11778A mutation did not impart any discernible difference in mitochondrial network morphology using widefield fluorescence microscopy. However, at the ultrastructural level, cells expressing this mutation exhibited an impairment of mitochondrial morphological plasticity when forced to utilize oxidative phosphorylation (OXPHOS) by transition to glucose-free, galactose-containing media. LHON fibroblasts also displayed a transient increase in mitophagy upon transition to galactose media. These results provide new insights into the consequences of the G11778A mutation of LHON and the pathological mechanisms underlying this disease.

p52-ZER6/IGF1R axis maintains cancer stem cell population to promote cancer progression by enhancing pro-survival mitophagy.

Cancer stem cells (CSCs), which are distinct subpopulations of tumor cells, have a substantially higher tumor-initiating capacity and are closely related to poor clinical outcomes. Damage to organelles can trigger CSC pool exhaustion; however, the underlying mechanisms are poorly understood. ZER6 is a zinc-finger protein with two isoforms possessing different amino termini: p52-ZER6 and p71-ZER6. Since their discovery, almost no study reported on their biological and pathological functions. Herein, we found that p52-ZER6 was crucial for CSC population maintenance; p52-ZER6-knocking down almost abolished the tumor initiation capability. Through transcriptomic analyses together with in vitro and in vivo studies, we identified insulin like growth factor 1 receptor (IGF1R) as the transcriptional target of p52-ZER6 that mediated p52-ZER6 regulation of CSC by promoting pro-survival mitophagy. Moreover, this regulation of mitophagy-mediated CSC population maintenance is specific to p52-ZER6, as p71-ZER6 failed to exert the same effect, most possibly due to the presence of the HUB1 domain at its N-terminus. These results provide a new perspective on the regulatory pathway of pro-survival mitophagy in tumor cells and the molecular mechanism underlying p52-ZER6 oncogenic activity, suggesting that targeting p52-ZER6/IGF1R axis to induce CSC pool exhaustion may be a promising anti-tumor therapeutic strategy.

Gene signatures of endoplasmic reticulum stress and mitophagy for prognostic risk prediction in lung adenocarcinoma.

Genes associated with endoplasmic reticulum stress (ERS) and mitophagy can be conducive to predicting solid tumour prognosis. The authors aimed to develop a prognosis prediction model for these genes in lung adenocarcinoma (LUAD). Relevant gene expression and clinical information were collected from public databases including Gene Expression Omnibus (GEO) and The Cancer Genome Atlas (TCGA). A total of 265 differentially expressed genes was finally selected (71 up-regulated and 194 downregulated) in the LUAD dataset. Among these, 15 candidate ERS and mitophagy genes (ATG12, CSNK2A1, MAP1LC3A, MAP1LC3B, MFN2, PGAM5, PINK1, RPS27A, SQSTM1, SRC, UBA52, UBB, UBC, ULK1, and VDAC1) might be critical to LUAD based on the expression analysis after crossing with the ERS and mitochondrial autophagy genes. The prediction model demonstrated the ability to effectively predict the 5-, 3-, and 1-year prognoses of LUAD patients in both GEO and TCGA databases. Moreover, high VDAC1 expression was associated with poor overall survival in LUAD (p < 0.001), suggesting it might be a critical gene for LUAD prognosis prediction. Overall, the prognosis model based on ERS and mitophagy genes in LUAD can be useful for evaluating the prognosis of patients with LUAD, and VDAC1 may serve as a promising biomarker for LUAD prognosis.

GSK-3α-BNIP3 axis promotes mitophagy in human cardiomyocytes under hypoxia.

Dysregulated autophagy/mitophagy is one of the major causes of cardiac injury in ischemic conditions. Glycogen synthase kinase-3alpha (GSK-3α) has been shown to play a crucial role in the pathophysiology of cardiac diseases. However, the precise role of GSK-3α in cardiac mitophagy remains unknown. Herein, we investigated the role of GSK-3α in cardiac mitophagy by employing AC16 human cardiomyocytes under the condition of acute hypoxia. We observed that the gain-of-GSK-3α function profoundly induced mitophagy in the AC16 cardiomyocytes post-hypoxia. Moreover, GSK-3α overexpression led to increased ROS generation and mitochondrial dysfunction in cardiomyocytes, accompanied by enhanced mitophagy displayed by increased mt-mKeima intensity under hypoxia. Mechanistically, we identified that GSK-3α promotes mitophagy through upregulation of BNIP3, caused by GSK-3α-mediated increase in expression of HIF-1α and FOXO3a in cardiomyocytes post-hypoxia. Moreover, GSK-3α displayed a physical interaction with BNIP3 and, inhibited PINK1 and Parkin recruitment to mitochondria was observed specifically under hypoxia. Taken together, we identified a novel mechanism of mitophagy in human cardiomyocytes. GSK-3α promotes mitochondrial dysfunction and regulates FOXO3a -mediated BNIP3 overexpression in cardiomyocytes to facilitate mitophagy following hypoxia. An interaction between GSK-3α and BNIP3 suggests a role of GSK-3α in BNIP3 recruitment to the mitochondrial membrane where it enhances mitophagy in stressed cardiomyocytes independent of the PINK1/Parkin.

A mitochondrial surveillance mechanism activated by SRSF2 mutations in hematologic malignancies.

Splicing factor mutations are common in myelodysplastic syndrome (MDS) and acute myeloid leukemia (AML), but how they alter cellular functions is unclear. We show that the pathogenic SRSF2P95H/+ mutation disrupts the splicing of mitochondrial mRNAs, impairs mitochondrial complex I function, and robustly increases mitophagy. We also identified a mitochondrial surveillance mechanism by which mitochondrial dysfunction modifies splicing of the mitophagy activator PINK1 to remove a poison intron, increasing the stability and abundance of PINK1 mRNA and protein. SRSF2P95H-induced mitochondrial dysfunction increased PINK1 expression through this mechanism, which is essential for survival of SRSF2P95H/+ cells. Inhibition of splicing with a glycogen synthase kinase 3 inhibitor promoted retention of the poison intron, impairing mitophagy and activating apoptosis in SRSF2P95H/+ cells. These data reveal a homeostatic mechanism for sensing mitochondrial stress through PINK1 splicing and identify increased mitophagy as a disease marker and a therapeutic vulnerability in SRSF2P95H mutant MDS and AML.

Predicting mitophagy-related genes and unveiling liver endothelial cell heterogeneity in hepatic ischemia-reperfusion injury.

Background: Hepatic Ischemia-Reperfusion Injury (HIRI) is a major complication in liver transplants and surgeries, significantly affecting postoperative outcomes. The role of mitophagy, essential for removing dysfunctional mitochondria and maintaining cellular balance, remains unclear in HIRI. Methods: To unravel the role of mitophagy-related genes (MRGs) in HIRI, we assembled a comprehensive dataset comprising 44 HIRI samples alongside 44 normal control samples from the Gene Expression Omnibus (GEO) database for this analysis. Using Random Forests and Support Vector Machines - Recursive Feature Elimination (SVM-RFE), we pinpointed eight pivotal genes and developed a logistic regression model based on these findings. Further, we employed consensus cluster analysis for classifying HIRI patients according to their MRG expression profiles and conducted weighted gene co-expression network analysis (WGCNA) to identify clusters of genes that exhibit high correlation within different modules. Additionally, we conducted single-cell RNA sequencing data analysis to explore insights into the behavior of MRGs within the HIRI. Results: We identified eight key genes (FUNDC1, VDAC1, MFN2, PINK1, CSNK2A2, ULK1, UBC, MAP1LC3B) with distinct expressions between HIRI and controls, confirmed by PCR validation. Our diagnostic model, based on these genes, accurately predicted HIRI outcomes. Analysis revealed a strong positive correlation of these genes with monocytic lineage and a negative correlation with B and T cells. HIRI patients were divided into three subclusters based on MRG profiles, with WGCNA uncovering highly correlated gene modules. Single-cell analysis identified two types of endothelial cells with different MRG scores, indicating their varied roles in HIRI. Conclusions: Our study highlights the critical role of MRGs in HIRI and the heterogeneity of endothelial cells. We identified the macrophage migration inhibitory factor (MIF) and cGAS-STING (GAS) pathways as regulators of mitophagy's impact on HIRI. These findings advance our understanding of mitophagy in HIRI and set the stage for future research and therapeutic developments.