📋 Browse Articles

Focal damage to articular cartilage incurred during joint injuries frequently progresses to post-traumatic osteoarthritis (PTOA) due to the limited intrinsic repair capacity of cartilage. Chondrogenic progenitor cells (CPCs) residing within the cartilage can contribute to repair if effectively recruited and activated. Early interventions that enhance CPC homing and their subsequent chondrogenesis offer a regenerative strategy to prevent PTOA progression, addressing the current lack of effective early clinical therapies. GDF5 stands out as a key protein involved in cartilage development, yet its potential to mobilize CPC-mediated regeneration remains underexplored. We evaluated the effects of GDF5 on CPC migration, proliferation, chondrogenic differentiation, and anti-catabolic activity using in vitro CPC models. To assess CPC chemotaxis in a clinically relevant biomaterial context, GDF5 was incorporated into a hyaluronic acid/fibrin interpenetrating network (IPN) hydrogel and tested in an ex vivo cartilage defect model. GDF5 acted as a potent chemoattractant for CPCs, promoting their recruitment toward cartilage defects when delivered via a hyaluronic acid/fibrin IPN hydrogel in an ex vivo model. GDF5 also enhanced CPC proliferation, consistent with activation of a glycolysis-associated transcriptional program. In addition, GDF5 significantly upregulated chondrogenic markers, including SOX9, COL2a1, and ACAN, and elevated extracellular matrix components in CPCs, potentially through activation of the PI3K/AKT signaling pathway. Furthermore, GDF5 reduced expression of a key catabolic enzyme ADAMTS5, possibly through the WWP2/miR-140 axis. These findings highlight the versatile role of GDF5 on endogenous CPCs. When combined with a hydrogel platform, GDF5 may serve as an early therapeutic strategy to convert injured cartilage from a passive site of degeneration into one of active regeneration. Show less

Osteoarthritis (OA) represents a prevalent degenerative joint condition, in which chondrocyte dysfunction plays a key role in disease progression. Although accumulating evidence underscores the importance of cellular stemness regulation in OA development, systematic screening of related biomarkers has been insufficient. The current study sought to discover and validate potential biomarkers through bioinformatics and machine learning (ML), offering novel perspectives for early detection and therapeutic intervention in OA. The present study examined six OA-related transcriptomic profiles from the Gene Expression Omnibus (GEO) to discover and validate stemness-associated biomarkers. Differentially expressed genes (DEGs) were selected and analyzed for enriched biological functions. OA-related modules were determined via weighted gene coexpression network analysis (WGCNA). Key stemness-related genes were selected using ML algorithms, including support vector machine (SVM), random forest (RF), extreme gradient boosting (XGBoost), and the least absolute shrinkage and selection operator (LASSO) regression. Receiver operating characteristic (ROC) analysis was implemented to determine diagnostic accuracy. Utilizing single-sample gene set enrichment analysis (ssGSEA), the link with immune cell infiltration was examined. Ultimately, immunohistochemistry was employed for experimental validation. Intersection analysis identified 56 stemness-related DEGs in OA cartilage. WGCNA analysis yielded 7 modules significantly associated with stemness genes, and a combined screening approach identified 60 candidate genes. Using four machine learning algorithms-SVM, LASSO, XGBoost, and RF-four feature genes were ultimately determined (WWP2, CDKN1A, IL11, and CRTAC1), among which WWP2, CDKN1A, and CRTAC1 showed significant differential expression between OA and normal samples and demonstrated good diagnostic performance in both the training and validation cohorts (AUC > 0.7). ssGSEA analysis revealed that the expression of these three genes was significantly correlated with specific immune cell subpopulations. Immunohistochemistry further confirmed that WWP2 and CDKN1A were downregulated in OA tissues, whereas CRTAC1 was upregulated. Through bioinformatics analysis and IHC validation, we identified three stemness-associated biomarker genes (WWP2, CDKN1A, CRTAC1) in OA. These findings may provide meaningful implications for future clinical assessment, treatment, and research on OA. Show less

Granulosa cell (GC) apoptosis is intrinsically linked to the ovarian dysfunction of polycystic ovary syndrome (PCOS). Although oxidative stress and apoptosis in GCs have been detected in PCOS patients, how reactive oxygen species (ROS) links to GC apoptosis in PCOS remains to be further elucidated. Here, by integrating public single-cell RNA-seq data with clinical GC sample validation, we found that the expression of the E3 ubiquitin ligase WWP2 was significantly reduced, whereas its role in PCOS has not been previously reported. Notably, we first demonstrated that WWP2 overexpression can effectively antagonize mitochondrial apoptosis and ROS in KGNs. Mechanistically, oxidative stress weakened the interaction between WWP2 and BAK and reduced WWP2 expression, thereby suppressing BAK ubiquitination at Lys113. This inhibition impaired proteasomal degradation and consequently increased BAK protein levels. Consistently, disrupting BAK ubiquitination (BAK-K113R mutant) or knocking down WWP2 facilitated KGN apoptosis, and genetic ablation of Wwp2 in PCOS mice further aggravated GC apoptosis and hormonal disturbances. This study elucidates the molecular mechanism by which oxidative stress modulates GC mitochondrial apoptosis through WWP2-mediated BAK ubiquitination, and establishes WWP2 as a potential therapeutic target for PCOS. Show less

Myocardial hypertrophy is one of the most prominent features of heart failure. SET domain-containing protein 7 (Setd7), a catalytic enzyme responsible for histone H3K4 methylation, has been implicated in various cardiac diseases. In this study we investigated whether Setd7 contributed to the development of cardiac hypertrophy. Male mice were subjected to a hypobaric hypoxic environment for 8 weeks; neonatal rat cardiomyocytes (NRCMs) exposed to hypoxia for 6 h. We showed that hypoxic stimulation significantly upregulated the expression levels of Setd7 along with the expression of hypertrophic markers ANP and BNP in NRCMs. By conducting loss- and gain-of-function assays, we demonstrated that Setd7 modulated the hypertrophic and inflammatory markers in hypoxic cardiomyocytes. We further revealed that Setd7-mediated activation of E2F1 (E2 promoter binding factor 1) triggered the expression of E3 ubiquitin protein ligases WWP2, which catalyzed the ubiquitination and degradation of glutathione peroxidase 4 (GPx4), a critical lipid peroxide-reducing enzyme. This degradation drove extensive lipid peroxidation, thereby exacerbating pathological cardiac hypertrophy. Notably, GPx4 inhibition by ras-selective lethal small molecule 3 (RSL3) abolished the antihypertrophic effects of Setd7 knockdown in cardiomyocytes, underscoring the pivotal role of lipid peroxidation in Setd7-mediated hypertrophic responses. In summary, Setd7 promotes hypoxia-induced cardiac hypertrophy through the Setd7-E2F1-WWP2-GPx4 signaling pathway, suggesting that targeting Setd7 is a promising therapeutic strategy to alleviate hypoxia-induced myocardial hypertrophy. Show less

Cisplatin resistance remains a major challenge in bladder cancer. Although the tumor suppressor ASPP2 is a critical co-factor for TP53-mediated apoptosis, its role in metabolic reprogramming and cisplatin response remains unclear. This study aimed to delineate the mechanism by which ASPP2 regulates cisplatin sensitivity through metabolic reprogramming. We first assessed the clinical significance of ASPP2 using patient tissues and public databases, finding that its downregulation in bladder cancer is associated with poor patient survival. Through gain- and loss-of-function studies in vitro and in vivo, we further demonstrated that ASPP2 inhibits the mevalonate (MVA) pathway independently of TP53 status, thereby sensitizing cells to cisplatin-induced DNA damage and apoptosis. This chemosensitizing effect was specifically reversed by the addition of MVA pathway metabolites. Moreover, WWP2 was identified as the E3 ubiquitin ligase responsible for ASPP2 degradation via K48-linked ubiquitination. Finally, WWP2 silencing was shown to stabilize ASPP2, suppress the MVA pathway, and synergize with cisplatin to impede tumor growth in mouse models. Overall, the WWP2-ASPP2-MVA pathway axis is identified as a novel driver of cisplatin resistance in bladder cancer. These results establish a mechanistic basis for targeting this axis to restore chemosensitivity, offering a promising therapeutic strategy for recalcitrant disease. Show less

Cerebral ischemia/reperfusion injury (CI/RI) is a common complication of cerebrovascular diseases such as stroke, characterized by mitochondrial dysfunction. This study investigates the function of proliferation-associated protein 2G4 (PA2G4) released by neural stem cells (NSCs)-derived exosomes (NSC-Exo) in treating middle cerebral artery occlusion/reperfusion (MCAO/R) by regulating mitophagy. NSC-Exo were extracted and identified. Treatment of NSC-Exo alleviated neurofunctional impairments in MCAO/R-induced mice, reduced oxidative stress and inflammatory responses in hippocampal tissues, and decreased neuronal apoptosis. We analyzed the alteration of molecular mechanisms under the effect of NSC-Exo treatment using bioinformatics analysis and RNA sequencing. PA2G4 was enriched in NSC-Exo, and the absence of PA2G4 in neurons impaired the mitigating effect of NSC-Exo on hippocampal neuronal injury and inhibited mitophagy. NSC-Exo delivered PA2G4 to recruit WW domain-containing protein 2 (WWP2), thereby mediating ubiquitination and degradation of Annexin A2 (ANXA2), and overexpression of PA2G4 or WWP2 reversed the accentuating effect of ANXA2 overexpression on MCAO injury. These findings indicate that PA2G4 delivered by NSC-Exo recruits WWP2 to mediate ubiquitination of ANXA2, thereby activating mitophagy to alleviate oxidative stress in hippocampal neurons in MCAO/R. This study offers a novel target for the treatment of CI/RI. Show less

Metabolic dysfunction-associated steatotic liver disease (MASLD) is a highly prevalent chronic liver disease worldwide and is closely associated with obesity, diabetes, and other metabolic disorders. Because MASLD progression poses serious health risks, elucidating the underlying mechanisms is essential to guide early intervention and therapeutic strategies. Proteomic analysis was used to identity high-fat diet (HFD)-induced proteins in mouse liver. Galectin-1 (GAL1) expression was assessed via immunohistochemistry in human liver tissues. Liver-specific GAL1-deficient mice were generated using adeno-associated virus. Mice were fed either a chow diet or an HFD. Functional studies were performed in cell lines using western blotting, RT-qPCR, immunofluorescence, co-immunoprecipitation, mass spectrometry, and molecular docking analysis. GAL1 expression was elevated in liver tissues from patients with MASLD and in mouse models. Liver-specific GAL1 knockdown alleviated hepatic steatosis and enhanced fatty acid oxidation (FAO). Mechanistically, GAL1 competitively bound to the BRCT domain of poly (ADP-ribose) polymerase 1 (PARP1), thereby interfering with its interaction with the WW domain -containing E3 ubiquitin protein ligase 2 (WWP2). Hepatic GAL1 knockdown promoted the PARP1 -WWP2 interaction and subsequently facilitated ubiquitin-dependent degradation of PARP1. This degradation led to increased NAD Hepatic deficiency of GAL1 alleviates hepatic steatosis by enhancing FAO through promotion of ubiquitin-dependent PARP1 degradation, thereby restoring NAD Show less

Defects in mitochondrial energy metabolism in injured tubular epithelial cells (TECs) are a well-recognized hallmark of kidney injury pathogenesis; however, the key target leading to this defect during the acute kidney injury (AKI)-to-chronic kidney disease (CKD) transition remains elusive. Here, we found that during the AKI-to-CKD transition, the increased WW domain containing E3 ubiquitin protein ligase 2 (WWP2) was shuttled to the mitochondria and disabled TEC mitochondrial energy metabolism by ubiquitinating and degrading complex II subunit succinate dehydrogenase complex subunit C (SDHC), leading to oxidative phosphorylation (OXPHOS) disability and aggravated TEC maladaptive repair. Preemptive and late depletion of Wwp2 both ameliorated unilateral ischemia-reperfusion (UIR) injury-induced AKI-to-CKD transition, and tubular-specific Wwp2 depletion resulted in the same protective phenotype. Furthermore, Sdhc knockdown abolished the protective effects of Wwp2 deletion in UIR mice. Conversely, SDHC overexpression attenuated OXPHOS impairment and TEC injury following WWP2 overexpression. Finally, we leveraged high-throughput virtual screening, enzyme activity assays, and binding affinity assays to identify two candidate WWP2 inhibitors. Both inhibitors significantly improved TEC maladaptive repair and deferred the AKI-to-CKD transition. Overall, we identified WWP2 as a critical regulator of mitochondrial OXPHOS integrity in maladaptive repairing TECs and identified two WWP2 inhibitors as potential drug candidates for interrupting the AKI-to-CKD transition. Show less

Tyrosine kinase inhibitors (TKIs) have transformed the treatment of EGFR-mutant non-small cell lung cancer (NSCLC); however, acquired resistance remains a major clinical challenge. While lysosomes have been implicated in drug resistance, their precise role in EGFR-TKI resistance remains unclear. In this study, we found that EGFR-TKI, including gefitinib and osimertinib, impaired WWP2-mediated proteasomal degradation of LAPTM4B. Through analysis of clinical tumor samples, genetic manipulation, and functional assays, we identify the lysosomal protein LAPTM4B as a key driver of EGFR-TKI resistance by enhancing EGFR phosphorylation and downstream signaling. Mechanistically, LAPTM4B interacts with ATP1A1 and facilitates its endocytosis, while simultaneously preventing its degradation by suppressing TRIM8-mediated K63-linked ubiquitination and proteasomal turnover. This stabilization of ATP1A1 enhances lysosomal acidification, ultimately promoting EGFR-TKI resistance. To identify potential therapeutic strategies, we conducted an unbiased high-content drug screen and identified compounds that suppress LAPTM4B expression. These compounds synergistically enhance the efficacy of EGFR-TKIs in NSCLC models Show less

Prostate cancer (PCa) is the most frequently diagnosed cancer in men and a leading cause of cancer-related death. While prostate-specific antigen is a widely used biomarker, its specificity is limited. This study investigated the prognostic significance of gene subsets associated with the ubiquitin-proteasome pathway in PCa. We analyzed transcriptomic and clinical data of 94 early-onset (age <55) patients with prostate cancer using public dataset. Differentially expressed genes linked to the ubiquitin-proteasome system were identified across cancer progression stages. Kaplan-Meier survival analysis, Cox regression, and least absolute shrinkage and selection operator (LASSO) modeling were applied to assess their prognostic potential. Differential expression of The identified gene subset provides novel prognostic insights into PCa progression and survival. These findings highlight potential biomarkers and therapeutic targets within the ubiquitin-proteasome pathway, offering new avenues for personalized treatment strategies. Show less

Cervical squamous cell carcinoma (CESC) is one of the most common cancers in women, and radiotherapy has been used as a primary treatment. However, its efficacy is limited by intrinsic and acquired radiation resistance. Our previous study demonstrated that Deoxycytidine kinase (dCK) inhibits ionizing radiation (IR)-induced cell death, including apoptosis and mitotic catastrophe, and dCK is a HSP90-interacting protein by mass spectrometry and co-immunoprecipitation assay. In the present study, we found that dCK inhibited IR-induced ferroptosis by increasing the activity and stability of SLC7A11. Using the E3 ubiquitin ligase database (UbiBrowser), we predicted NEDD4L as a potential ubiquitin ligase of dCK, and WWP1/2 as potential ubiquitin ligases of NEDD4L, respectively. These predictions were subsequently verified through a ubiquitination IP assay. Our findings indicate that HSP90 regulates dCK stability by inhibiting NEDD4L through the recruitment of ubiquitin ligases WWP1/2. In summary, our study reveals the HSP90-WWP1/WWP2-NEDD4L-dCK-SLC7A11 axis as a critical regulator of IR-induced ferroptosis in HeLa cells. These findings provide valuable insights into potential strategies for the radiosensitization of cervical cancer. Show less

Mammalian α-arrestins are members of the same arrestin family as the ubiquitously expressed and extensively studied β-arrestins. Arrestins share common structural elements, including the conserved N- and C-arrestin-fold domains, polar core, finger loop, and C-terminal tail, all of which mediate protein-protein interactions. In β-arrestins, these domains enable the control of G protein-coupled receptor (GPCR) signaling and scaffolding interactions with various signaling proteins including c-Src. By contrast, the repertoire of α-arrestin scaffolding partners and regulatory mechanisms that control their interactions are not well-understood. α-arrestins differ considerably from β-arrestins in the C-terminal region; β-arrestins contain clathrin adaptor β-adaptin-binding sites, whereas α-arrestins harbor PPxY motifs, demonstrated to interact with WW domains of E3 ubiquitin ligases such as WWP2. Here we report the identification of a novel phosphorylation site, tyrosine (Y) 394, embedded in the C-terminal PPxY motif of α-arrestin ARRDC3. The Y394 site functions as a phospho-regulatory switch to enable distinct ARRDC3 binding partners and scaffolding functions. We found that ARRDC3 Y394 phosphorylation promotes interaction with c-Src via its SH2 domain, whereas the non-phosphorylated form binds to WWP2. Our results further show that ARRDC3 Y394 phosphorylation and c-Src SH2 domain-dependent interaction enables regulation of c-Src activity, whereas ARRDC3 Y394 phosphorylation disrupts WWP2 interaction and perturbs ARRDC3-dependent lysosomal trafficking of the GPCR, protease-activated receptor-1. Together, these findings indicate that ARRDC3 Y394 functions as a phospho-regulatory switch to enable selective binding to different partners that impact distinct scaffolding functions. Show less

Colorectal cancer (CRC) remains one of the most prevalent and lethal malignancies worldwide, with cancer stemness and metastasis being critical factors contributing to poor prognosis. While circular RNAs are emerging as important regulators in cancer progression, the role of circGIGYF1 in CRC development is poorly understood. Here, we found that downregulated circGIGYF1 is linked to poor survival rate in CRC patients. circGIGYF1 inhibits CRC stemness, epithelial-mesenchymal transition, and metastatic potential both in vitro and in vivo. Mechanistically, circGIGYF1 promotes the interaction between WWP2 and HOXD13, enhancing HOXD13 ubiquitination and subsequent degradation. This degradation prevented HOXD13 from binding to the CTNNB1 promoter, thereby suppressing Wnt/β-catenin signalling pathway activation. Importantly, circGIGYF1 overexpression or HOXD13 knockdown significantly reduces tumor growth and liver metastasis in mouse models. These findings reveal a circGIGYF1/WWP2/HOXD13/β-catenin regulatory axis in CRC progression and highlight circGIGYF1 as a potential therapeutic target for developing strategies to combat CRC metastasis and recurrence. Show less

NACHT, LRR, and PYD domains-containing protein 3 (NLRP3) inflammasome plays a pivotal role in the progression of cerebral ischemia/reperfusion injury (CI/RI). We aimed to investigate the implication of WW domain-containing protein 2 (WWP2), an E3 ubiquitin ligase, in CI/RI and its mechanism. Microglia were subjected to oxygen-glucose deprivation/reoxygenation, and mice were subjected to middle cerebral artery occlusion (MCAO) for modeling. WWP2 was reduced in the brain tissues of mice with MCAO/R. WWP2 overexpression in microglia inhibited the NLRP3 inflammasome activation to alleviate MCAO/R-induced injury and microglia-induced neurotoxicity. WWP2 inhibited the mitochondrial translocation of NLRP3 by degrading mitochondrial antiviral-signaling protein (MAVS) to block its interaction with NLRP3, and MAVS overexpression in microglia promoted the NLRP3 activation to exacerbate MCAO/R and neurotoxicity. The nuclear export of TAR DNA-binding protein 43 (TDP-43) in MCAO/R promoted the WWP2 degradation via the (UG)n element of the 3'UTR of WWP2. TDP-43 overexpression also impaired the blockade of NLRP3 activation and exacerbated neurotoxicity in the presence of WWP2. Overall, our investigations demonstrate that nuclear export of TDP-43 in microglia activates NLRP3 inflammasome and exacerbates CI/RI by blocking MAVS degradation through (UG)n element-mediated instability of WWP2. Show less

The phosphorylation of signal transducer and activator of transcription 3 (STAT3) monomer at S727 promotes its mitochondrial localisation and regulates mitochondrial function, thus exerting a protective effect on tumour cells. However, no inhibitor drugs targeting mitochondrial STAT3 (mitoSTAT3) or S727-STAT3 phosphorylation have been identified. Here, we report a novel diterpenoid extracted from Isodon sculponeatus, sculponeatin A (sptA), induces mitochondrial dysfunction in non-small cell lung cancer (NSCLC) by targeting mitoSTAT3 degradation. xCELLigence real-time cell analysis assay and high-content analysis were performed to measure cytotoxicity. Mitochondrial function was assessed by transmission electron microscopy, mitochondrial permeability transition pore opening and Seahorse cellular flux assays. The effects of sptA on the upstream signalling pathway of mitochondrial dysfunction were measured by Western blot, gene alterations and other approaches. Immunofluorescence and live cell imaging were performed to visualise the expression and position of mitoSTAT3. Nude mice and zebrafish were modelled with subcutaneous xenografts. Pharmacokinetics of sptA were examined in rats. Drug toxicity was evaluated in zebrafish. sptA inhibited mitochondrial respiration in NSCLC cells. sptA induced mitochondrial dysfunction by promoting the degradation of mitoSTAT3. sptA promoted WW domain containing E3 ubiquitin protein ligase 2 (WWP2)-mediated ubiquitination and degradation of mitoSTAT3 through direct binding. sptA inhibited tumour growth in vivo. Evaluation of drug toxicity in zebrafish showed that overdose of sptA may cause heart damage. These findings suggest that pharmacological targeting the degradation of mitoSTAT3 by sptA may provide therapeutic benefits against NSCLC. Show less

Indole-3-carbinol (I3C) is a metabolic derivative of glucobrassicin found in cruciferous vegetables. Known for its anticarcinogenic properties, I3C has been shown to target the NEDD4 family HECT E3 ligases, NEDD4-1 and WWP1, yet Show less

The NEDD4-like E3 ubiquitin ligase, WWP2, is involved in a range of host processes from cell differentiation to T cell immunity. Ligase activity is tightly regulated, with WWP2 being held in an autoinhibited state. The binding of a PY motif-containing adaptor, an Ndfip, via the WW domains of NEDD4-like E3 ubiquitin ligases leads to their disinhibition. Here, we show that the canonical Ndfip, NDFIP2, requires multiple PY motifs for interaction with and activation of WWP2. In contrast, the single PY-motif containing Ndfips TMEM127 and SUSD6 functions as a co-disinhibitory pair. TMEM127 and the Salmonella protein SteD also function as a co-disinhibitory pair. However, SteD requires a different region of WWP2, the C2 domain, for interaction with WWP2, and this interaction results in disinhibition of WWP2. These findings demonstrate a range of ways that Ndfips can disinhibit WWP2. To our knowledge, these are the first examples of two Ndfips functioning as co-disinhibitory pairs, and of a bacterial effector that disinhibits an E3 ubiquitin ligase. Show less

Diabetic retinopathy (DR) is the main cause of blindness worldwide, and its prevalence rate is constantly rising. More in-depth exploration of its risk factors and pathogenic mechanisms is needed. This study systematically identified potential therapeutic targets for DR by evaluating causal effects of 16,989 genes and 2,923 proteins on DR/subtypes via two-sample Mendelian randomization (MR), validated with colocalization/Summary-data-based Mendelian randomization (SMR). National Health and Nutrition Examination Survey (NHANES) 1999-2010 cross-sectional data (weighted logistic/Restricted cubic spline (RCS)) pinpointed key risk factors; MR explored their links to DR subtypes. Bioinformatics (bulk and single-cell transcriptomics) analyzed molecular mechanisms of shared targets (gene expression, immune infiltration, pathway enrichment). Machine learning selected key targets for models. Finally, two-step mediation MR examined how targets regulate DR via risk factors. This study identified 64 core targets with causal links to DR. Subtype analysis revealed 2,128 causal genes and subtype-specific targets (e.g. 52 for background DR, 66 for proliferative DR). SMR validated these findings. NHANES data highlighted body mass index (BMI), stroke, hypertension (HBP), and C-reactive protein (CRP) as key DR risk factors, confirmed by MR. Transcriptomics identified 29 differentially expressed genes associated with both risk factors and DR, linked to immune cell regulation. Machine learning selected core targets (LY9, WWP2, etc.) and built a nomogram for DR risk prediction. Functional enrichment showed these targets enriched in chemokine/cytokine and immune-inflammatory pathways. Two-step mediation MR further revealed LY9, ARHGAP1, and WWP2 influence DR subtypes via regulating BMI, CRP, and HBP. This study systematically elucidates the key risk factors, potential molecular mechanisms, and core regulatory targets of DR through multi-omics integration, causal inference, and bioinformatics approaches. The results indicate that inflammation, immune dysregulation, and metabolic disorders play crucial roles in the pathogenesis of DR. Key genes such as LY9, ARHGAP1, and WWP2 could serve as potential intervention targets, offering theoretical foundations and strategic support for early warning and precision treatment of DR. Show less

Metabolic abnormalities have become a prominent hallmark of malignant tumor and play a crucial role in the occurrence and development of lung adenocarcinoma (LUAD). however, the underlying mechanism involved this process is still far from being fully elucidated. In this study, we aimed to explore the essential factors regulating the glycolysis and proliferation process in LUAD. Bioinformation and immunohistochemistry were applied to screen and verify the expression pattern of the vital factors in LUAD. A series of biological function assays, including Cell Counting Kit 8 (CCK8), colony formation, 5-ethynyl-2'-deoxyuridine‌ (EdU), seahorse assays and nude mouse transplantation tumor assays, were performed to demonstrate the impact of the family with sequence similarity 189 member A2 (FAM189A2) on the glycolysis and proliferation process in LUAD. Co-immunoprecipitation, immunofluorescence and dual-luciferase reporter gene and RT-qPCR were used to verify the FAM129A2 and the WW domains of E3 ubiquitin ligase (WWP2) interaction, as well as the influence of their combination on large tumour suppressor-1 (LATS1) ubiquitination level and Hippo signaling pathway activity. FAM189A2 was weakly expressed in the cytoplasm of LUAD, and associated with the poor prognosis of patients. FAM189A2 overexpression inhibited the glycolysis and proliferation processes of LUAD cells in vitro. Meanwhile, both the processes were enhanced following FAM189A2 knockdown. Mechanistically, FAM189A2 was identified to interact with WWP2 through its own PPxY motifs, hence weakened the WWP2-LATS1 affinity and inhibited the WWP2-mediated LATS1 ubiquitination, which ultimately resulted in a reduced yes-associated protein (YAP) nuclear translocation. In addition, Verteporfin (Hippo pathway inhibitor) or YAP knockdown could eliminate the biological effects of promoting proliferation and glycolysis in LUAD cells caused by FAM189A1 silence. FAM189A2 can be considered as a potential diagnostic and prognostic marker associated with LUAD, and suppresses the proliferation and glycolytic metabolism of LUAD cells via WWP2-LATS1-YAP signaling, which will provide a corresponding theoretical foundation for the development of small molecule inhibitors. Show less

Ischemic stroke (IS) is a severe disease. The altered activation states of microglia play important roles in IS. In present study, a total of 125 C57BL/6 mice was used (N = 6 per group). Middle cerebral artery occlusion (MCAO) and oxygen-glucose deprivation (OGD) were performed for in vivo and in vitro model construction. The infarct size was detected using TTC staining. The nerve injury was evaluated by a neurological deficit score. OGD-treated brain microvascular endothelial cells (BMECs) were co-cultured with BV2 cells. Cell viability was determined by CCK-8 assay, and the apoptosis rate was identified by flow cytometry analysis. Transendothelial electronic resistance (TEER) of the cells was measured by TEER measurement. Molecular interactions were analyzed using dual-luciferase reporter gene, ChIP, and Co-IP assays. All in vitro experiments were conducted with three replicates, and each experiment was performed in triplicate. We found that Src Homology 2B Adaptor Protein 3 (SH2B3) was overexpressed in the cerebral cortex tissues of MCAO treated mice (P < 0.01), and BMECs co-cultured with BV-2 cells under OGD conditions (P < 0.01). SH2B3 knockdown or Myocyte Enhancer Factor 2 A (MEF2A) overexpression reduced infarct size and improved neurological function in MCAO mice. SH2B3 knockdown enhanced OGD-treated cell viability (P < 0.05), inhibited cell apoptosis (P < 0.05) in BMECs, and ameliorated BBB (P < 0.01). Moreover, SH2B3 knockdown changed the activation status of microglia. MEF2A promoted the transcriptional activation of WW Domain Containing E3 Ubiquitin Protein Ligase 2 (WWP2) and WWP2 promoted the ubiquitination and degradation of SH2B3. SH2B3 overexpression reversed the effects of MEF2A overexpression on microglia states, BMECs injury and BBB function. In summary, MEF2A promoted the ubiquitination-mediated degradation of SH2B3 via transcription up-regulating WWP2, then changed the activation status of microglia, thus ameliorating BMEC injury, and finally ameliorating IS injury. Show less

Hepatocellular carcinoma (HCC) is a leading cause of cancer-related mortality worldwide. The E3 ubiquitin ligase WWP2 has emerged as a critical regulator of tumor pathogenesis through its modulation of substrate ubiquitination. However, its specific mechanistic role in HCC remains poorly understood. In this study, we found that WWP2 was significantly up-regulated in HCC patients and associated with poor prognosis. Lentivirus-mediated knockdown of WWP2 induced cellular senescence and suppressed proliferation in HCC cell lines. Mechanistically, co-immunoprecipitation and ubiquitination assays identified WWP2 as a novel E3 ubiquitin ligase for p21 that promotes its K48-linked ubiquitination and subsequent proteasomal degradation, consequently accelerating cellular senescence and restraining HCC progression. Notably, we further discovered that CMTM6 directly interacts with WWP2, thereby stabilizing p21 by preventing its WWP2-mediated ubiquitination. Accordingly, the senescence and proliferation arrest induced by WWP2 deficiency were partially reversed by CMTM6 knockdown but enhanced by concurrent CMTM6 overexpression. This functional interplay was corroborated in vivo, as WWP2 depletion enhanced tumor cell senescence and suppressed tumor growth, an effect that was partially rescued by concurrent CMTM6 knockdown. Taken together, our findings establish the WWP2-CMTM6-p21 axis as a pivotal regulatory mechanism of cellular senescence in HCC and shed new light on senescence-related therapeutic strategies for HCC. Show less

Cisplatin is a widely used chemotherapeutic agent in the treatment of non-small cell lung cancer (NSCLC), but cisplatin resistance remains a significant clinical challenge. Lysosomal transmembrane protein 5 (LAPTM5) is a lysosomal membrane protein implicated in macroautophagy/autophagy, although its precise mechanism has yet to be fully elucidated.In this study, we demonstrated that LAPTM5 promotes cisplatin resistance in NSCLC by maintaining lysosomal membrane stability and preserving autophagic flux. Mechanistic investigations showed that LAPTM5 competes with LAMP1 for binding to WWP2, thereby inhibiting LAMP1 ubiquitination and degradation, which ultimately preserves lysosomal membrane stability. LAPTM5 knockdown increases lysosomal membrane permeability, leading to the release of cathepsin D (CTSD), which elevates intracellular reactive oxygen species (ROS) levels; further destabilizing the lysosomal membrane and accelerating cell death. Our findings elucidate the mechanism by which LAPTM5 contributes to cisplatin resistance through lysosomal membrane stabilization and identify LAPTM5 as a potential therapeutic target for overcoming cisplatin resistance in NSCLC. Show less

Cisplatin resistance in tongue squamous cell carcinoma (TSCC) correlates with poor prognosis, where natural killer (NK) cells in the tumor microenvironment (TME) play a crucial role. This study investigated the mechanism by which exosomes from cisplatin-resistant TSCC cells suppress NK cell function. We found that exosomal long non-coding RNA SNHG26, highly enriched in cisplatin-resistant TSCC cells and their exosomes, was transferred to NK cells. Within NK cells, SNHG26 acted as a scaffold promoting WWP2-mediated ubiquitination and degradation of the transcription factor SOX2, thereby inhibiting HLA-DRA transcription and subsequent IL-2/JAK-STAT5 signaling. Concurrently, SNHG26 competitively bound miR-515-5p, relieving its suppression of TGFB1 mRNA and activating the TGF-β1/Smad2 pathway. These dual mechanisms significantly impaired NK cell proliferation, activation, and cytotoxicity. SNHG26 depletion reversed NK cell suppression and cisplatin resistance in vitro and in vivo. Thus, our study identifies exosomal SNHG26 as a key mediator of cisplatin resistance and NK cell dysfunction in TSCC, suggesting its potential as a promising therapeutic target. Show less

Blood-based biomarkers in epilepsy could constitute important research tools advancing neurobiological understanding and valuable clinical tools for better diagnosis and follow-up. An interesting question is whether biomarker patterns could contribute additional understanding compared to individual marker values. We analyzed OLINK proteomics data from a large epilepsy cohort in which we have previously found four differentially expressed proteins (CDH15, PAEP, LTBP3, PHOSPHO1). Using two machine-learning techniques, we identified ten consensus candidate protein biomarkers (CDH15, PAEP, LTBP3, PHOSPHO1, NEFL, SFRP1, TDGF1, DUSP3, WWP2 and DSG3) that contributed to the classification of patients as being seizure-free or not. Six out of the ten consensus proteins were identified as differentially expressed in our previous study (although NEFL and TDGF1 not significantly so after multiple testing correction). The remaining four consensus proteins were newly identified by machine learning and were chosen for detailed analysis. In comparison to the four significantly differentially expressed proteins (CDH15, PAEP, LTBP3, PHOSPHO1), the newly identified consensus proteins (SFRP1, DSG3, DUSP3, and WWP2) and in particular a combination of all eight proteins, outperformed individual proteins in identifying individuals with recent seizures, highlighting the potential of multi-protein profiles. These findings emphasize the need for integrative bioinformatic approaches in epilepsy research and underscore the role of neuroinflammation and immune pathways in epileptogenesis. Our results support the applicability of plasma protein profiling for developing future blood-based tests for epilepsy seizure prediction, diagnosis, and treatment. Further validations in independent cohorts are required to establish these candidate biomarkers in clinical practice. Show less

Mitophagy plays a critical role in maintaining mitochondrial quality and cellular homeostasis. But the specific contribution of mitophagy-related E3 ubiquitin ligases to prognoses remains largely unexplored. In this study, we identified a novel mitophagy-related E3 ubiquitin ligase prognostic signature using least absolute shrinkage and selector operator (LASSO) and multivariate Cox regression analyses in breast cancer. Based on median risk scores, patients were divided into high-risk and low-risk groups. Functional enrichment analyses were conducted to explore the biological differences between the two groups. Immune infiltration, drug sensitivity, and mitochondrial-related phenotypes were also analyzed to evaluate the clinical implications of the model. A four-gene signature (ARIH1, SIAH2, UBR5, and WWP2) was identified, and Kaplan-Meier analysis demonstrated that the high-risk group had significantly worse overall survival (OS). The high-risk patients exhibited disrupted mitochondrial metabolism and immune dysregulation with upregulated immune checkpoint molecules. Additionally, the high-risk group exhibited higher sensitivity to several drugs targeting the Akt/PI3K/mTORC1 signaling axis. Accompanying mitochondrial metabolic dysregulation, mtDNA stress was elevated, contributing to activation of the senescence-associated secretory phenotype (SASP) in the high-risk group. In conclusion, the identified signature provides a robust tool for risk stratification and offers insights into the interplay between mitophagy, immune modulation, and therapeutic responses for breast cancer. Show less

The poor prognosis of glioblastoma (GBM) patients is attributed mainly to abundant neovascularization and presence of glioblastoma stem cells (GSCs). GSCs are preferentially localized to the perivascular niche to maintain stemness. However, the effect of abnormal communication between endothelial cells (ECs) and GSCs on GBM progression remains unknown. Here, we reveal that ECs-derived SEMA3G, which is aberrantly expressed in GBM patients, impairs GSCs by inducing c-Myc degradation. SEMA3G activates NRP2/PLXNA1 in a paracrine manner, subsequently inducing the inactivation of Cdc42 and dissociation of Cdc42 and WWP2 in GSCs. Once released, WWP2 interacts with c-Myc and mediates c-Myc degradation via ubiquitination. Genetic deletion of Sema3G in ECs accelerates GBM growth, whereas SEMA3G overexpression or recombinant SEMA3G protein prolongs the survival of GBM bearing mice. These findings illustrate that ECs play an intrinsic inhibitory role in GSCs stemness via the SMEA3G-c-Myc distal regulation paradigm. Targeting SEMA3G signaling may have promising therapeutic benefits for GBM patients. Show less

Transcription factor EB (TFEB) is a key transcription factor that orchestrates the cellular response to stress. Dysregulation of TFEB is associated with a range of human diseases, and understanding the regulatory mechanisms of TFEB is crucial for identifying potential drug targets. In this study, we used Show less

The mechanistic target of rapamycin (mTOR) pathway plays a critical role in cell growth and metabolic homeostasis. The ribosomal protein S6 kinases S6K1 and S6K2 are the major effectors of the mTOR pathway key to translation efficiency, but the underlying regulatory mechanisms remain largely unclear. In this study, we searched for mTOR regulators and found that the splicing factor SRRM2 modulates the levels of S6K1 and S6K2, thereby activating the mTOR-S6K pathway. Interestingly, SRRM2 facilitates the expression of S6K2 by modulating alternative splicing, and enhances the stability of the S6K1 protein by regulating the E3 ubiquitin ligase WWP2. Moreover, SRRM2 is highly expressed in colorectal cancer (CRC) tissues and is associated with a poor prognosis. SRRM2 promotes CRC growth in vitro and in vivo. Combined, these data reveal an oncogenic role of SRRM2 in CRC through activating the mTOR-S6K pathway by two different approaches, further suggesting SRRM2 as a potential therapeutic target for CRC. Show less