Cellular lipid droplet (LD) turnover is essential for metabolic homeostasis in liver, and failures in LD clearance are increasingly linked to fatty liver disease. We describe a previously unrecognized mechanism of LD turnover and a human disorder caused by its disruption. A 2-year-old boy with metabolic dysfunction-associated steatotic liver disease (MASLD) was found by exome sequencing to carry an ultrarare homozygous C12ORF54 missense variant (c.134A>G; p.Q45R). We find that wild-type C12ORF54 is a conserved protein that binds LDs via a central amphipathic helix and tethers to lysosomes through an N-terminal helix interaction with the BORC subunit KXD1, enabling direct deposition of LDs into lysosomes. The p.Q45R substitution sterically destabilizes the amphipathic helix, abolishes KXD1 binding, prevents LD and lysosome targeting and blocks LD deposition. Proband cells accumulate LDs and acyl lipid species, lipotoxic stress due to excess ROS, and exhibit cell-cycle arrest and cell death. This study implicates defective direct lysosomal LD deposition as a cause of childhood-onset MASLD-like hepatic phenotype, and finds the C12ORF54-KXD1 interaction axis as a potential contributor to LD homeostasis in liver.
Circular RNAs (circRNAs) have emerged as stable post-transcriptional regulators that influence gene expression, cellular adaptation, and disease pathogenesis through mechanisms including microRNA (miRNA) interaction, RNA-binding protein modulation, and signaling-network regulation. Generated through the back-splicing process that produce covalently closed RNA loops, circRNAs exhibit remarkable stability, evolutionary conservation, and tissue-specific expression patterns, enabling them to function as miRNA sponges, protein scaffolds, transcriptional modulators, and, in some cases, translational templates. Increasing evidence indicates that dysregulated circRNA expression contributes to a broad spectrum of human diseases, highlighting their diagnostic and therapeutic potential. Among the molecular pathways influenced by circRNAs, Sirtuin 1 (SIRT1), an NAD+-dependent deacetylase and a modulator of metabolic homeostasis, stress adaptation, inflammation, autophagy, and aging, has emerged as a particularly important target. Recent studies have revealed that circRNAs regulate SIRT1 through complex post-transcriptional and signaling networks, thereby influencing cellular fate decisions in both malignant and non-malignant disorders. Importantly, the biological consequences of circRNA-mediated SIRT1 modulation appear highly context-dependent, with protective or pathogenic effects varying according to tissue type, metabolic state, and disease stage. In this review, we provide a comprehensive and integrative discussion of the circRNA-SIRT1 regulatory axes across diverse pathological conditions, from common metabolic disorders to life-threatening cancers. Beyond summarizing current evidence, we propose the circRNA-SIRT1 network as a context-dependent post-transcriptional regulatory network linking non-coding RNA (ncRNA) biology to immunometabolic and stress-response pathways. We further discuss emerging translational opportunities and circRNA-targeted therapeutics, emphasizing the potential of this regulatory axis as a promising platform for precision diagnostics and disease-specific therapeutic interventions.
Parkinson's disease (PD), the world's second most prevalent neurodegenerative disorder, is characterized by midbrain substantia nigra dopaminergic (DA) neuron loss, neuroinflammation, and α-synuclein aggregation. c-Cbl, a RING-finger E3 ubiquitin ligase highly expressed in the substantia nigra and striatum, regulates neuroinflammation via the NF-κB pathway. Prior studies showed that reduced c-Cbl expression triggers microglia-mediated neuroinflammation in LPS- and MPTP-induced PD models, but whether c-Cbl overexpression suppresses NLRP3 inflammasome activation to alleviate PD-related neuroinflammation remains unclear. We established LPS-induced chronic neuroinflammatory and Parkin-deficient PD models, confirming downregulated c-Cbl expression. In vitro, LV-c-Cbl overexpression in PC12 cells mitigated NLRP3 activation, autophagy dysfunction, and DA neuron loss. In vivo, stereotaxic AAV-c-Cbl injection in LPS model mice and Parkin+/- mice inhibits NLRP3 inflammasome activation via the NF-κB signaling pathway, autophagic impairment, DA neuron damage, and motor dysfunction. Collectively, c-Cbl is a promising therapeutic target for PD.
Dysregulation of the ubiquitin-proteasome system contributes to hepatocellular carcinoma (HCC), but how deubiquitination is linked to transcriptional regulation and alternative splicing remains unclear. In this study, proteomic analysis identified E2F4 as a PSMD14-interacting protein. Co-immunoprecipitation and ubiquitination assays showed that PSMD14 removed K48-linked polyubiquitin chains from E2F4, thereby reducing its degradation and increasing its protein stability. Stabilized E2F4 directly bound to the PHF5A promoter and promoted PHF5A transcription. As a component of the spliceosome, PHF5A regulated alternative splicing in HCC cells, including exon 3 skipping of NASP and exon 3 inclusion of POLA1. Silencing PSMD14, E2F4, or PHF5A inhibited HCC cell proliferation, whereas re-expression of the corresponding downstream factors partially restored cell growth, supporting a functional PSMD14-E2F4-PHF5A regulatory axis. Treatment with the proteasome-associated inhibitor O-phenanthroline (OPA) reduced E2F4 and PHF5A expression, altered NASP and POLA1 splicing, and suppressed xenograft tumor growth. Moreover, overexpression of E2F4 or PHF5A partially reversed OPA-induced splicing changes and growth inhibition in vitro. These findings identify a PSMD14-E2F4-PHF5A pathway that connects protein deubiquitination with transcriptional regulation and alternative splicing, and suggest that this pathway may represent a potential therapeutic vulnerability in HCC.
OBJECTIVE:This study aims to investigate the role and molecular mechanism of USP22 in diabetic retinopathy (DR), focusing on its regulation by histone lactylation and a positive feedback loop with HIF-1α. METHODS:A DR mouse model was established via intraperitoneal injection of STZ, and in vitro DR models were induced using high glucose (HG) treatment in ARPE-19 and mRPE. Cell damage was assessed through CCK-8, EdU staining, and other experiments, while retinal damage was evaluated via H&E staining and TUNEL staining. RESULTS:In DR models both in vivo and in vitro, USP22 expression was significantly elevated. Knockdown of USP22 alleviated retinal damage in DR mice and reduced injury in ARPE-19 and mRPE cells exposed to HG, an effect associated with suppressed glycolysis. HIF-1α was also upregulated in DR. Co-IP assays confirmed that USP22 stabilizes HIF-1α through deubiquitination. Overexpression of HIF-1α partially reversed the inhibitory effects of USP22 knockdown on glycolysis and cellular damage under HG conditions. Furthermore, ChIP analysis revealed that lactate, a glycolytic product, promotes USP22 transcription and expression via H3K18la modification, forming a glycolysis/H3K18la/USP22/HIF-1α positive feedback loop. HIF-1α overexpression reversed the glycolysis inhibitor 2-DG-induced suppression of USP22 H3K18la modification and expression in HG-exposed cells, while attenuating the protective effect of 2-DG against cellular injury. Consistently, in vivo, knockdown of USP22/HIF-1α or 2-DG treatment downregulated USP22, Pan Kla, and H3K18la in DR retinas, while ameliorating retinal structural damage and apoptosis. CONCLUSION:Our study reveals that a "glycolysis/H3K18la/USP22/HIF-1α" positive feedback loop exists in DR, promoting disease progression.
Pancreatic cancer (PC) is a highly lethal malignancy characterized by aggressive progression and limited treatment options. Current standard-of-care treatments only confer marginal survival benefits, highlighting an urgent unmet clinical need to identify novel actionable targets and mechanism-driven therapeutic regimens. Focal adhesion kinase (FAK, encoded by PTK2) is frequently dysregulated across a broad spectrum of cancers and tightly associated with malignant tumor phenotypes, yet its precise clinical relevance and druggable potential in PC remain incompletely elucidated. This study systematically evaluated the diagnostic and prognostic value of PTK2/FAK in PC, and dissected the anti-tumor efficacy and underlying molecular mechanism of the selective FAK inhibitor Defactinib. We confirmed that PTK2 was significantly overexpressed in PC tissues, serving as a high-accuracy diagnostic biomarker with an AUC of 0.959 and an independent risk factor for unfavorable prognosis. PTK2-high tumors exhibited marked enrichment of the PI3K/AKT oncogenic signaling pathway, and MYC was validated to directly transcriptionally upregulate PTK2, where patients with concurrent MYC-high and PTK2-high tumors showed the worst clinical outcomes. Using in vitro functional assays and two distinct genetically engineered mouse models, we demonstrated that Defactinib potently suppressed tumor proliferation and induced caspase-3-dependent apoptosis via blockade of the PI3K/AKT cascade. Notably, Defactinib also triggered ULK1-mediated compensatory protective autophagy, and co-administration with the autophagy inhibitor chloroquine effectively abrogated this process to substantially amplify the anti-tumor effect. Our findings validate PTK2 as a clinically meaningful prognostic biomarker and promising therapeutic target, providing robust new preclinical evidence to support the clinical translation of PTK2-targeted combination therapies for PC.
Despite advances in current therapeutic strategies, osteosarcoma remains a highly aggressive malignancy with limited treatment options. Rutaecarpine (Rut), an indolopyridoquinazolinone alkaloid with selective cyclooxygenase-2 inhibitory activity, has been reported to possess diverse pharmacological properties; however, its anti-osteosarcoma mechanisms remain poorly defined. Here, we examined the anti-tumor activity of Rut and the signaling pathways underlying its biological effects. Rut reduced MG63 cell viability in a concentration-dependent manner and promoted apoptotic cell death, as demonstrated by TUNEL staining and changes in apoptosis-related proteins. Rut also impaired cell-cycle progression and induced reactive oxygen species-mediated mitochondrial dysfunction, accompanied by modulation of the NRF2/HO-1 pathway and autophagic responses. Proteome profiling identified PRAS40 as a major signaling component associated with the cellular response to Rut. Consistent with this finding, Rut suppressed PRAS40 phosphorylation, leading to activation of GSK3β-associated signaling and subsequent inhibition of cell migration, invasion, extracellular matrix degradation, and anchorage-independent colony formation through reduced expression of MMP-2, MMP-9, and MMP-13. The biological relevance of these findings was further supported using a newly established ex vivo calvaria-osteosarcoma metastasis model, in which Rut attenuated tumor-associated bone destruction while preserving newly formed bone, collagen matrix organization, and the viability of osteoblasts and osteocytes along the periosteal surface. Overall, the present findings suggest that Rut suppresses osteosarcoma progression by modulating the PRAS40-associated signaling network and supports its potential as a therapeutic agent for osteosarcoma-associated bone destruction.
N6-methyladenosine (m6A) is a prevalent epitranscriptional modification in RNA that is crucial for RNA metabolism and biogenesis. Accumulating evidence reveals a complex interplay between m6A and protein post-translational modifications (PTMs)-covalent additions of chemical groups or structural alterations to nascent proteins during or after biosynthesis. This crosstalk involves in disease development and drug response by altering protein properties and functions. However, comprehensive discussion about the roles and mechanisms of m6A and PTMs crosstalk is limited. Here, we present an up-to-date review of this emerging and complex interplay in disease and therapeutic response. We first summarize the crosstalk between m6A and PTMs such as ubiquitination, lactylation, acetylation, phosphorylation, and methylation, organizing our discussion around the three major regulatory factors m6A writers, erasers, and readers. Next, we explore the mechanism of m6A-PTMs crosstalk involved in the pathogenesis and development of diseases, including various cancers, metabolic disorders, and inflammatory diseases. Moreover, we discuss the role of m6A-PTMs crosstalk in drug response, focusing on chemotherapy drugs. In summary, this review provides a framework for understanding the regulatory networks of m6A-PTMs crosstalk in disease pathogenesis, development, and therapeutic response, highlighting potential treatment strategies based on this interplay and suggesting future research directions.
Physical inactivity and mechanical unloading induce skeletal muscle atrophy and are associated with systemic metabolic disorders, but the molecular basis linking muscle disuse to liver injury remains unclear. Human cohort analyses (CHARLS, NHANES), a mouse hindlimb immobilization model, and multi-level in vitro systems were used to define this mechanism. Muscle disuse activates skeletal muscle indoleamine 2,3-dioxygenase 1 (IDO1), accompanied by altered tryptophan metabolism and increased systemic kynurenine accumulation. Kynurenine functioned as a circulating pathogenic mediator that activates hepatic aryl hydrocarbon receptor (AhR) signaling, resulting in oxidative stress, hepatocyte injury, and fibrotic remodeling. Importantly, pharmacological inhibition of IDO1 in vivo and siRNA-mediated IDO1 knockdown in vitro reduced kynurenine-associated AhR signaling and attenuated hepatocyte injury-related phenotypes. These findings identify an IDO1-kynurenine-AhR axis associated with muscle atrophy-related liver pathology and suggest that skeletal muscle IDO1 activation contributes to inter-organ metabolic communication during physical inactivity. Targeting this pathway may provide a therapeutic strategy to mitigate systemic complications associated with disuse and sedentary conditions.
B-cell acute lymphoblastic leukemia (B-ALL) is a prevalent hematological malignancy, posing difficulties in identifying efficacious treatment strategies for refractory and recurrent patients. Our research revealed that coactivator-associated arginine methyltransferase 1 (CARM1) was highly expressed in B-ALL and associated with unfavorable prognostic outcomes. Down-regulation and inhibition of CARM1 effectively suppressed proliferation and colony formation of B-ALL, while also inducing apoptosis and cell cycle arrest. Mechanistically, inhibition or down-regulation of CARM1 reduced PARP1 level and contributed to double-strand breaks (DSBs) accumulation. Inhibition of CARM1 and PARP1 synergistically supressed B-ALL development. Significantly, the inhibition of CARM1 was found to promote memory differentiation and reduce the exhaustion of CD19-CAR-T cells. Taken together, CARM1 inhibition not only suppressed B-ALL but also enhanced the durability of CAR-T cells against B-ALL, which provides novel insights into the tumor suppression and immune regulation of CARM1 inhibition on cancer therapy.
BACKGROUND:Cervical cancer (CC) remains a public health challenge in developing countries. Epidermal growth factor receptor (EGFR) is a receptor tyrosine kinase highly expressed in CC. Studies showed that PGE2 may transactivate EGFR in some models. However, understanding the interaction between the EGFR and PGE2 signaling pathways in CC is a key area for investigation. METHODS:The Cancer Genome Atlas (TCGA) was used to evaluate gene expression correlation and clinical outcomes. Panitumumab and aspirin were employed to inhibit EGFR and COX-1/2, respectively. Cell migration was evaluated using Boyden chamber. MTT and clonogenic assays determined cell viability and clonogenicity. Western Blotting analyzed protein expression. PGE2 was measured in the supernatants of cell lines using ELISA. Flow cytometry was used for cell death assays. RESULTS:TCGA analysis revealed a significant positive correlation between EGFR and COX-1, COX-2, and microsomal prostaglandin E synthase-1 (mPGES-1). CC patients showed decreased overall survival upon overexpression of EGFR or COX-2. CASKI and HeLa cells were cisplatin-resistant, whereas C33A cells were chemosensitive. CASKI cells exhibited the highest EGFR levels, while HeLa cells showed highest levels of COX-2 and mPGES-1. HeLa cells showed marked upregulation of COX-2 and mPGES-1 and increased PGE2 secretion upon EGF stimulation. Moreover, PGE2 activated ERK signaling and promoted cell migration through an EGFR-dependent mechanism. Panitumumab plus aspirin impaired cell viability, clonogenicity and chemoresistance. Simultaneous stimulation with EGF and PGE2 mitigated cisplatin-induced apoptosis in CASKI cells. CONCLUSION:The interactions between EGFR and PGE2 signaling pathways link inflammation and oncogenic signaling, promoting tumor aggressive behavior.
Although immune checkpoint inhibitors (ICIs) have revolutionized the treatment landscape of solid tumors, response rates in patients with small cell lung cancer (SCLC) remain limited, and acquired resistance is highly prevalent. The underlying mechanisms of this immunotherapy resistance remain to be fully elucidated. Clinically, SCLC typically manifests as an "immune-cold" tumor, characterized by a low abundance of CD8+ T cell infiltration and the rare formation of tertiary lymphoid structures (TLS). While DNA damage repair (DDR) is closely linked to innate immune responses, how DDR networks orchestrate the SCLC immune microenvironment remains obscure. In this study, we integrated single-cell transcriptomic data (comprising 344,447 high-quality cells) from six cancer types (BCC, CRC, HCC, HNSCC, iCCA, and SCLC). Our comparative analysis revealed a fundamental depletion of TLS-associated cellular subpopulations (e.g., CXCL13+ CD8+ T cells, HLA-DRB5+ B cells, and CXCL9+ dendritic cells) in SCLC, which was significantly correlated with aberrant DDR activity. Through high-dimensional weighted gene co-expression network analysis (hdWGCNA), we identified ZNF385A as the core hub gene within the DDR-associated module. ZNF385A is highly expressed in SCLC and is associated with poorer prognosis. In vitro, ZNF385A depletion suppressed SCLC cell proliferation and induced apoptosis, accompanied by R-loop accumulation and activation of cGAS-STING signaling, indicating a potential link between ZNF385A, genomic stability and tumor-intrinsic innate immune signaling. Collectively, these findings identify ZNF385A as a potential regulator associated with TLS deficiency and immune evasion in SCLC.
Atherosclerosis (AS) is a chronic inflammatory vascular disease driven by endothelial dysfunction, and dysregulated ubiquitination has emerged as an important pathogenic mechanism. Although deubiquitinating enzymes (DUBs) are key regulators of protein homeostasis, the role of USP40 in AS remains unknown. Here, we defined the function and mechanism of USP40 in cellular and animal models of AS. USP40 expression was reduced in the aortic endothelium of atherosclerotic mice and in ox-LDL-treated human umbilical vein endothelial cells (HUVECs). In Western diet-fed ApoE-/- mice, AAV9-mediated USP40 overexpression markedly reduced aortic plaque burden, lipid accumulation, collagen deposition, and macrophage infiltration without altering circulating lipid levels. Conversely, USP40 knockdown aggravated ox-LDL-induced endothelial apoptosis and NLRP3 inflammasome activation. Mechanistically, USP40 interacted with SIRT1 and stabilized it by removing K48-linked polyubiquitin chains, thereby preventing proteasomal degradation. SIRT1 depletion substantially reversed the anti-apoptotic and anti-inflammatory effects of USP40. These findings reveal a previously unrecognized USP40/SIRT1 axis that protects the endothelium and limits atherosclerosis, highlighting USP40 as a potential therapeutic target for AS.
BACKGROUND:Myocardial Ischemia-Reperfusion Injury (MIRI) is a key pathological link in the treatment of myocardial infarction (MI), leading to further necrosis of cardiomyocytes and deterioration of cardiac function. The abnormal expression and function of voltage-dependent anion channel 1 (VDAC1) has been confirmed to be closely related to MIRI. This study aims to explore the effects and mechanisms of VDAC1 on MI development. METHODS:By establishing an in vitro cardiomyocyte hypoxia-reoxygenation (H/R) model and an in vivo rat model, and combining techniques including flow cytometry, fluorescent probe assay, Western blotting, Hematoxylin-eosin (HE) staining and Masson's trichrome staining, the effects of VDAC1 silencing on AC16 cardiomyocyte injury, ferroptosis regulation, mitochondrial function, and cardiac function improvement were analyzed. Co-immunoprecipitation (Co-IP) assay, chromatin immunoprecipitation (ChIP) assay, and dual-luciferase reporter assay were used to verify the interactions of ubiquitin-specific protease 11 (USP11) and transcription factor YY1 with VDAC1. RESULTS:VDAC1 was highly expressed in AC16 under H/R induction. Silencing VDAC1 enhanced cell viability, inhibited cell apoptosis, inflammatory factor expression and ferroptosis, and alleviated mitochondrial dysfunction. By inhibiting the ubiquitination-dependent degradation pathway of VDAC1, USP11 realized the stable regulation of VDAC1 protein and affected the cell damage, ferroptosis, and mitochondrial dysfunction of AC16 cells. YY1 reversed these alterations by positively regulating the transcriptional expression of VDAC1. Intervention with VDAC1 knockdown lentivirus improved cardiac function, reduced inflammation, and inhibited ferroptosis in rats. CONCLUSION:This study confirmed for the first time that USP11 and YY1 promoted the expression of VDAC1 through deubiquitination modification and transcriptional activation, respectively, and mediated the occurrence and development of MIRI, providing potential intervention targets for the clinical treatment of MI.
Background Atrial fibrillation (AF) is an age-related disease associated with substantial morbidity and mortality. Although rapamycin stands as a foremost anti-aging therapy with proven efficacy in lifespan extension, a critical gap exists in understanding its impact on aging-induced atrial remodeling and AF susceptibility. Objective This study aims to evaluate the therapeutic potential of rapamycin against aging-related AF and elucidate its underlying mechanisms. Methods An aging-induced AF-susceptible mouse model was induced by D-galactose injection, followed by rapamycin diet. Subsequent evaluations included AF susceptibility, atrial electrical/structural remodeling, and mechanistic analyses. Results Rapamycin significantly reduced aging-induced AF susceptibility. It also ameliorated atrial electrical and structural remodeling. Metabolically, it improved systemic insulin resistance, restored mitochondrial function and morphology, and counteracted aging-induced perturbations in substrate utilization. Mechanistically, rapamycin inhibited hypoxia inducible factor-1α (HIF-1α) transcriptional activity, a key metabolic target in the aging process. Cellular experiments confirmed that rapamycin directly suppressed CoCl₂-induced HIF-1α expression and nuclear translocation, and pharmacological restoration of HIF-1α effectively attenuates the protective effects of rapamycin against D-galactose-induced atrial structural remodeling. Furthermore, molecular docking, dynamics simulations and isothermal titration calorimetry (ITC) suggested that rapamycin may also directly interfere with HIF-1α dimerization. Importantly, restoration of mTOR activity failed to reverse rapamycin-mediated HIF-1α inhibition, suggesting an mTOR-independent regulatory mechanism. Conclusion Our findings demonstrate that rapamycin mitigates aging-induced atrial remodeling and AF susceptibility in mice, primarily through the inhibition of HIF-1α and the amelioration of downstream metabolic dysregulation.
Gastric cancer (GC) is a globally lethal malignancy, with invasion and metastasis driving treatment failure and poor prognosis. MX dynamin like GTPase 1 (MX1) shows tumor-specific functional heterogeneity, while its expression, biological functions and molecular mechanisms in GC remain unclear. Here, we explored MX1's clinical significance and its regulatory mechanism in GC cell migration. We integrated public databases and institutional paired clinical samples for bioinformatics analysis of MX1's correlation with clinical outcomes, and verified its pro-migratory effect via Transwell and wound healing assays. Co-immunoprecipitation/mass spectrometry (Co-IP/MS), immunofluorescence and ubiquitination assays were used to identify MX1-interacting proteins and dissect the underlying mechanism, and the Genomics of Drug Sensitivity in Cancer database was applied for chemosensitivity analysis. MX1 was aberrantly upregulated in GC tissues and served as an independent prognostic biomarker, with high expression associated with shortened overall, first-progression and post-progression survival. MX1 promoted GC cell migration and epithelial-mesenchymal transition pathway enrichment, and directly bound Annexin A2 (ANXA2) in the cytoplasm; both were co-enriched in endothelial and epithelial cells by single-cell sequencing. MX1 dose-dependently upregulated ANXA2 protein (without affecting its mRNA) by inhibiting NEDD4L/TRIM65-mediated ANXA2 ubiquitination and degradation, enhancing ANXA2 stability. Additionally, high MX1 expression correlated with increased paclitaxel sensitivity in GC patients based on database analysis, and CCK-8 assays confirmed that MX1 overexpression significantly reduced the paclitaxel IC50 in gastric cancer cells, supporting its potential as a predictive biomarker for paclitaxel efficacy. This study demonstrates that MX1 promotes GC cell migration by suppressing ANXA2 ubiquitination and degradation, highlighting the critical role of the MX1-ANXA2 axis in GC progression. These findings provide novel molecular targets and theoretical support for GC prognostic evaluation, individualized chemotherapy and targeted therapy.
Muscles are contractile tissues commonly classified into skeletal, cardiac, and smooth muscle. Each type exhibits distinct structural and functional properties that rely on coordinated signaling pathways to maintain homeostasis and adapt to physiological demands. The primary cilium is a solitary, microtubule-based organelle that protrudes from the cell surface and functions as a sensory platform for mechanical and chemical cues. Growing evidence has implicated primary cilia in the regulation of muscle biology. In skeletal muscle, primary cilia are present in quiescent satellite cells, where they contribute to the regulation of activation, self-renewal, and hypertrophic responses through signaling pathways such as Hedgehog and Wnt. In cardiac tissue, primary cilia have been identified in cardiac fibroblasts and developmental cardiac cell populations, where they have been associated with fibrogenic responses, cardiac remodeling, and developmental signaling pathways. Similarly, in smooth muscle cells, primary cilia participate in mechanosensory signaling and have been implicated in the regulation of proliferative and migratory responses, particularly in vascular pathology. Alterations in ciliary structure or signaling components have been associated with impaired muscle regeneration, increased adipogenesis, and maladaptive tissue remodeling. This review examines the current evidence regarding the role of primary cilium in skeletal, cardiac, and smooth muscle and discusses its potential relevance in muscle disease, providing an integrated overview of cilium-dependent signaling across muscle tissues.
Type I interferons (IFN-I) are central to antiviral immunity, but their excessive or sustained production can result in immunopathological damage. RIG-I-like receptor (RLR) signaling is pivotal in regulating RNA virus-induced IFN-I responses and requires precise modulation to maintain immune homeostasis. Here, we report that viral infection induced elevated expression of Eukaryotic translation initiation factor 2 alpha kinase 2 (EIF2AK2), which is an interferon-stimulated gene (ISG) with unclear role in the innate immunity. Using EIF2AK2-deficient mice and cells, we demonstrated that the loss of EIF2AK2 specifically enhances RNA virus-induced IFN-I production in macrophages and suppresses the replication of RNA virus vesicular stomatitis virus (VSV), and that this function is tightly associated with the N-terminal dsRNA binding domain of EIF2AK2. Mechanistically, EIF2AK2 competes with RIG-I for binding viral RNA, thereby inhibiting RIG-I activation. In addition, EIF2AK2 promotes the translocation of p-MLKL to mitochondria via recruiting VAMP8, leading to disruption of mitochondrial membrane potential and dysfunction of MAVS, ultimately inhibiting IFN-I production. These findings identify EIF2AK2 as a critical negative regulator of RLR-mediated innate immune response to RNA viruses via dual inhibitory mechanisms, and suggest its potential as a therapeutic target for controlling dysregulated IFN-I responses.
Cancer-associated fibroblasts (CAFs) are key components of the tumor microenvironment and play important roles in cancer progression and treatment resistance. Despite recognized heterogeneity among CAFs, their specific contributions to chemoresistance in gastric cancer (GC) remain incompletely understood. This study identifies THY1+ CAFs as a distinct subset associated with poor patient outcomes and oxaliplatin resistance in GC. Both in vitro and in vivo analyses confirmed that THY1+ CAFs promote oxaliplatin resistance in GC cells via extracellular vesicles (EVs). Inhibition of EV secretion reduced the chemoresistance-enhancing effects of THY1+ CAFs. Proteomic profiling of EVs identified COL11A1 as a protein enriched in THY1+ CAF-derived EVs, which was further validated by immunofluorescence and Western blot. Depletion of COL11A1 in THY1+ CAF-EVs substantially attenuated their ability to enhance drug resistance in GC cells. High infiltration of COL11A1+ and THY1+ CAFs was correlated with reduced overall survival and recurrence-free survival in GC patients. RNA sequencing and pathway analysis revealed that THY1+ CAF-EVs induce oxaliplatin resistance by activating the PI3K/AKT signaling pathway. Targeting PI3K/AKT signaling counteracted EV-induced chemoresistance, and COL11A1 knockdown in THY1+ CAF-EVs reduced PI3K/AKT activation. In conclusion, COL11A1 packaged in THY1+ CAF-derived EVs promotes GC chemoresistance via PI3K/AKT signaling, highlighting a potential therapeutic target for overcoming chemoresistance in GC.
Nelfinavir (NFR), originally developed as an antiretroviral agent for the human immunodeficiency virus, has demonstrated anti-cancer properties across various malignancies; however, its therapeutic potential in Glioblastoma (GBM) remains largely unexplored. In the present study, we investigated the anti-tumor effects of NFR in GBM using a comprehensive panel of experimental models, including established GBM cell lines, GBM cell line-derived spheroids, patient-derived primary glioma cells, and patient-derived glioma organoids. We further evaluated the anti-tumor potential of NFR in combination with standard chemotherapeutic agents, carboplatin and doxorubicin, across these platforms. In vitro analyses revealed that NFR significantly inhibits GBM cell proliferation and induces both apoptotic and necrotic cell death. Additionally, we identified that NFR treatment is associated with activation of the AIM2 inflammasome in GBM cells and may contribute to NFR-induced anti-glioma effects. However, activation of the AIM2 inflammasome alone is not essential to induce its anti-tumor effects in GBM. Collectively, our findings highlight NFR as a promising therapeutic candidate for GBM, exerting its effects through anti-proliferative and pro-death mechanisms.
