Proteostasis is maintained by the coordinated action of the ubiquitin–proteasome system (UPS) and autophagy–lysosome pathways. Valosin-containing protein (VCP/p97), an AAA + unfoldase, sits at its intersection by extracting ubiquitinated clients and assembling cofactor-defined complexes that determine substrate fate. In cancer, VCP up-regulation and altered cofactor recruitment rewire these ubiquitin-dependent routing decisions. By recruiting E3 ligases and deubiquitinases that remodel K48- and K63-linked ubiquitin chains, VCP biases substrates toward Ufd1–Npl4-coupled proteasomal turnover or autophagy-linked clearance, enabling oncogene stabilization or tumor suppressor loss. These principles are reflected in cancer axes that modulate autophagy flux, invasion and metastasis, PI3K/AKT/mTOR signaling, and immune evasion. The tumor suppressor p53 illustrates this complexity with state-dependent outcomes: VCP promotes proteasomal turnover of wild-type p53 through the canonical Ufd1–Npl4 complex, whereas it can stabilize the R273H hotspot mutant in a chaperone/holdase-like manner, prolonging gain-of-function phenotypes. Opposing regulators further control VCP function: PLAC8 enhances VCP–Ufd1–Npl4 activity and is linked to wild-type p53 turnover, PI3K/AKT/mTOR activation, and context-dependent autophagy effects. In contrast, SVIP can outcompete other VCP cofactors and, via acylation-dependent membrane targeting, redirect VCP toward lysosome-associated functions with predominantly tumor-suppressive effects. Collectively, this framework motivates therapeutic strategies that modulate VCP–cofactor interactions to regulate substrate degradative fate. Approaches include disrupting the Ufd1–Npl4 axis, biasing VCP from UPS to autophagy, altering subcellular localization, and reprogramming VCP for targeted proteolysis, with implications for cancer, fibrosis, neurodegeneration, and multisystem proteinopathy.
Immunosenescence—the age-related decline in immune competence—has emerged as a critical contributor to the development, progression, and treatment resistance of gastrointestinal (GI) tumors. Hallmarked by T cell exhaustion, chronic low-grade inflammation, and the accumulation of immunosuppressive cell populations, immunosenescence profoundly reshapes the tumor immune microenvironment and weakens antitumor immunity. In GI tumors, this process is further driven by senescence-associated secretory phenotype (SASP), mitochondrial dysfunction, and non-coding RNA networks, all of which contribute to immune evasion and therapeutic resistance. Concurrently, the gut microbiota serves as a pivotal modulator of immune aging, mediating a “microbiota–immunity–tumor” axis through microbial metabolites and proinflammatory signaling. Emerging therapeutic strategies—including senolytics, SASP inhibitors, immune-rejuvenating agents, and microbiota-targeted interventions—have demonstrated promising efficacy in preclinical models of colorectal, gastric, hepatic, and pancreatic cancers (PCs). Collectively, advancing mechanistic insights into immunosenescence in GI tumors and developing senescence-based precision therapies may offer new opportunities to enhance immunotherapeutic outcomes, particularly in aging and immunocompromised populations.
Accumulating evidence suggests that B lymphocyte dysfunction plays a critical yet underappreciated role in tumor immune evasion. Beyond regulatory B cell (Breg)-mediated immunosuppression, defects in tumor-infiltrating B cell antigen presentation, immunosuppressive antibody isotypes, and aberrant B cell spatial organization can undermine sustained anti-tumor immunity, ultimately compromising both clinical outcomes and the efficacy of immunotherapies. These findings highlight the need to target non-Breg-mediated immunosuppression beyond Bregs alone. To be effective, therapeutic strategies must accomplish two objectives in the tumor immune microenvironment: convert the tumor microenvironment from immunosuppressive to immunostimulatory and transform weak anti-tumor responses into robust ones. Achieving this will require novel approaches that combine spatiotemporal transcriptomic analysis with precision-targeted interventions to dismantle B-cell-driven immunosuppressive mechanisms and fully realize the therapeutic potential of cancer immunotherapy.
Renal osteodystrophy is a debilitating complication of chronic kidney disease characterized by deteriorated bone microarchitecture and impaired bone formation, leading to increased fracture risk. Despite the pressing need for anabolic therapies, the cellular mechanisms by which uremic stress compromises osteoprogenitor function remain poorly defined. Here, metabolomic profiling of renal osteodystrophy patient cohorts revealed a profound depletion of circulating betaine. We show that betaine supplementation not only rescued the osteogenic differentiation of bone marrow-derived mesenchymal stem cells challenged with the uremic toxin indoxyl sulfate but also ameliorated skeletal deterioration in a rat model of chronic kidney disease. Mechanistically, we demonstrated that indoxyl sulfate triggered ferroptosis in bone marrow-derived mesenchymal stem cells—characterized by iron-dependent lipid peroxidation and aberrant HMOX1 up-regulation—thereby arresting osteogenesis. Betaine mitigates this ferroptotic stress through a novel post-transcriptional mechanism. Specifically, betaine down-regulated the RNA-binding protein hnRNP A1, preventing the recruitment of the CNOT1 deadenylase complex. This inhibition stabilized Abcg1 mRNA, leading to restored ABCG1 expression. Functional perturbation studies confirmed that the ABCG1–HMOX1 axis was indispensable for the anti-ferroptotic and osteoprotective effects of betaine. Collectively, our findings delineate a Betaine–hnRNP A1/CNOT1–ABCG1–HMOX1 signaling cascade that links metabolic deficiency to ferroptosis-driven osteogenic failure, positioning betaine as a promising anabolic therapeutic strategy for renal osteodystrophy.
Autism spectrum disorder (ASD) is a neurodevelopmental disorder characterized by social communication deficits, restricted interests and repetitive behaviors. Reliable biomarkers and mechanism-based therapeutic targets for ASD remain limited. This study investigated the involvement of the ADAM10/N-cadherin axis in ASD-associated synaptic abnormalities using clinical samples and a prenatal valproic acid (VPA)-induced rat model. Plasma N-cadherin levels were measured in children with ASD (n = 30) and age- and sex-matched typically developing (TD) controls (n = 28). After exclusion of two statistical outliers from the TD group, plasma N-cadherin levels did not differ significantly between the ASD and TD groups; however, plasma N-cadherin levels were positively correlated with personal-social developmental quotient in children with ASD. To explore the underlying mechanism, ADAM10-mediated N-cadherin processing was examined in the prefrontal cortex (PFC) of VPA-exposed rats. Prenatal VPA exposure increased membrane-associated ADAM10, reduced full-length N-cadherin (N-cadherin-FL) levels, and elevated the ratio of N-cadherin C-terminal fragments (N-cadherin-CTF) to full-length N-cadherin, indicating enhanced proteolytic processing of N-cadherin. TAT-Pro-ADAM10 (709–729) treatment partially restored N-cadherin-FL levels, reduced the elevated N-cadherin-CTF/N-cadherin-FL ratio, and ameliorated aberrant synaptic plasticity in the PFC. RNA sequencing revealed broad transcriptomic alterations following prenatal VPA exposure, whereas Adam10 and Cdh2 mRNA levels remained unchanged, indicating that the ADAM10/N-cadherin alterations are not primarily driven by transcriptional regulation. Collectively, these findings suggest that dysregulated ADAM10-mediated N-cadherin cleavage is associated with prefrontal synaptic dysfunction in the VPA model and support the clinical relevance of plasma N-cadherin in relation to social developmental function in children with ASD.
Early-onset colorectal cancer (EOCRC), diagnosed before age 50, is becoming more common worldwide, now making up 10% of new cases. Data from SEER indicate that these patients often present with advanced disease and more aggressive tumor features. Its increasing clinical prominence requires revealing the underlying molecular and immune mechanisms and improving prevention and treatment strategies, representing an important gap in current clinical practice and fundamental research. We established an age-stratified AOM-DSS colorectal cancer (CRC) model in mice, employing single-cell RNA sequencing to compare the tumor microenvironments of EOCRC and late-onset colorectal cancer (LOCRC). EOCRC samples showed a reduced T cell fraction, with their immune cells enriched in lipid and amino acid metabolism, in contrast to activated immune-related pathways in LOCRC. Mechanistically, in EOCRC, Emp1 expression was up-regulated in malignant epithelial cells via Pparg, which facilitates lipid metabolism remodeling to support the malignant phenotype. Meanwhile, they actively interacted with CD8+ T cells via the LGALS9–CD45 axis, promoting an immunosuppressive tumor microenvironment. Through functional assays using primary tumor cells (e.g., Western blotting, EdU assay, flow cytometry) and a co-culture system with CD8+ T cells, we validated these bioinformatic findings. We further validated age-associated spatial transcriptional signatures in human CRC tissues. In vivo experiments revealed that the Pparg–Emp1 axis impaired CD8+ T cell function by inducing an immunosuppressive lipid microenvironment. Either genetic knockdown or pharmacological intervention targeting this axis exerted CD8+ T cell-dependent anti-tumor effects and synergized with anti-PD-1 immunotherapy. The research unveils the distinct malignant phenotype of EOCRC and its immune characteristics, necessitating prevention and treatment approaches tailored for the younger population.
Junctional adhesion molecule 3 (JAM3) has been increasingly recognized as a critical regulator of cell migration and adhesion, and JAM3 mutation in humans results in severe skeletal dysplasia and death. However, the underlying mechanism by which JAM3 regulates bone formation is unclear. Here, we identified increased JAM3 levels in both osteoblast and adipocyte differentiation. Functional experiments revealed that JAM3 in bone marrow mesenchymal stromal cells (BMSCs) promoted osteoblast differentiation while inhibiting adipogenesis. In vivo, both the bone marrow cavity-delivered Jam3 siRNA mouse model and the osteoblast progenitor-specific Jam3 conditional knockout mouse model (Osx-Cre; Jam3fl/fl) consistently exhibited a marked reduction in osteoblasts, an increase in adipocytes and osteoclasts, and a significant decrease in tibial bone mass and bone density. It has been demonstrated that JAM3 can activate LRP5 protein. Structural modeling using AlphaFold3, combined with molecular dynamics simulations, confirmed that JAM3 could form a stable complex with LRP5. Consistently, cellular assays demonstrated that JAM3 suppressed the degradation of LRP5, supporting its role in stabilizing the receptor. Mechanistic studies confirmed that inhibiting β-catenin activation significantly reversed the effect of JAM3 on regulating osteogenesis/adipogenesis differentiation in BMSCs. Regarding osteoclast differentiation, overexpression of JAM3 in BMSCs led to an increased Rankl/Opg ratio, indicating that JAM3 promotes osteoclastogenesis and bone resorption via a RANKL-dependent pathway. This study provides evidence that JAM3 in BMSCs reciprocally regulates bone homeostasis by modulating LRP5/β-catenin and down-regulating the expression of RANKL.
Multiciliated cells (MCCs) are essential for airway innate defense through mucociliary clearance, yet the diversity of MCCs in the healthy human airway remains poorly defined, hindering the understanding of their dysfunction in chronic respiratory diseases. In this study, we first profiled multiple anatomical regions of the healthy airway, including the turbinate, nasal sinus, nasopharynx, trachea, proximal bronchi, distal bronchi, and bronchioles. Morphological evaluation of MCCs revealed a progressive proximal-to-distal decline in their coverage, ciliary length, and axonemal diameter in the lower respiratory tract. Single-cell RNA sequencing further identified five distinct MCC subtypes whose distribution exhibited marked heterogeneity across airway anatomical regions. At the molecular level, proximal bronchial MCCs exhibited enrichment of antioxidant pathways with up-regulation of NQO1 and TXN compared with bronchiolar MCCs, a finding validated by spatial transcriptomics and immunofluorescence. Organoid experiments functionally confirmed that bronchiolar organoids accumulated significantly higher levels of reactive oxygen species than bronchial organoids upon cigarette smoke extract stimulation. In diseased conditions (nasal polyps, asthma, and COPD), we identified 22 commonly up-regulated and 4 commonly down-regulated genes in MCCs relative to matched control regions, pointing to shared injury features across chronic respiratory diseases. Moreover, we discovered that FTO and IRF9 were significantly up-regulated in MCCs from COPD patients but markedly down-regulated in those from asthma patients, highlighting disease-specific ciliary alterations. This atlas delineates the regional morphological and molecular landscape of airway MCCs, identifies the antioxidant deficiency of distal MCCs as a previously unrecognized feature, and reveals novel targets for therapeutic intervention in chronic respiratory diseases.
Proteolysis-targeting chimeras (PROTACs) represent a revolutionary therapeutic modality that hijacks the ubiquitin–proteasome system (UPS) to achieve selective degradation of pathogenic proteins. Unlike conventional inhibitors, PROTACs can eliminate previously "undruggable" targets, offering unique advantages such as high potency and the potential to overcome drug resistance. Despite advances in the treatment of kidney diseases, a common limitation is the lack of effective therapies that can precisely target the core protein drivers of renal pathology. This review aims to systematically elucidate the theoretical rationale for applying PROTAC technology to address key challenges in nephrology, comprehensively summarize its preclinical progress across a range of kidney diseases, and thoroughly analyze the core obstacles from molecular design to clinical translation. With its innovative strategy of mechanistically eliminating disease-causing proteins, PROTAC technology holds the potential to revolutionize the treatment of kidney disease and usher in a new era of precision medicine.
Papillary thyroid cancer (PTC) exhibits high morbidity and promising outcomes, but local advance and metastasis occasionally occur in the clinic with unknown mechanisms. E26 transformation-specific (ETS) domain protein ETV4 has been linked with various processes, including normal tissue development and tumorigenesis. However, the mechanism underlying ETV4-mediated tumorigenesis in PTC remains unclear. Here, we showed that ETV4 was predominantly expressed by PTC cancer cells and was associated with aggressive clinicopathological characteristics. Biological analyses showed that ETV4 served as an oncogene to promote PTC growth and metastasis by driving epithelial–mesenchymal transition (EMT) in vitro and in vivo. Mechanistically, ETV4 directly bound to the promoter of TGFB1 and recruited p300 to catalyze histone H3 lysine 18 lactylation (H3K18la) to synergistically increase chromatin accessibility around the TGFB1 promoter region, resulting in increased TGFB1 transcription and excessive secretion of TGFβ1 protein. In PTC cells, TGFβ1 activated the intracellular SMAD2/3 signaling pathway in an autocrine manner to induce the activation of the EMT-related transcriptional program and EMT-driven tumor progression. Pharmacologically, inhibition of the histone acyltransferase activity of p300 by a C646 inhibitor impaired the growth and metastatic ability of PTC by impeding p300–H3K18la-mediated TGFB1 transcription. Overall, these findings identify the oncogenic role of ETV4 in contributing to PTC progression and reveal a novel mechanism by which ETV4 cooperates with p300-mediated H3K18la to drive the transcription of specific target genes. This work provides insights into therapeutic strategies for PTC by targeting the functional connection between ETV4 and p300-mediated histone lactylation to drive autocrine TGFβ1 signaling activation.
Correct mRNA splicing is important for maintaining heart function, and dysregulation of this process can result in heart failure. However, the molecular mechanisms underlying this process, particularly the role of RNA-binding protein (RBP) in regulating mRNA splicing, remain largely unclear. We identified RBM27 as an important regulator of cardiac function and diseases. Abnormal RBM27 expression was associated with myocardial infarction-induced heart failure. Cardiomyocyte-specific overexpression of RBM27 ameliorated myocardial infarction-induced heart failure, whereas cardiomyocyte-specific deletion of Rbm27 led to dilated cardiomyopathy and heart failure due to exon11 skipping in Tnnt2. TNNT2, but not TNNT2Δexon11, rescued heart failure in Rbm27-CKO mice. The RNA recognition motif (RRM) of RBM27 was essential for maintaining cardiac function by ensuring normal alternative splicing of Tnnt2. RBM27 bound directly to the exon 11 region of Tnnt2 mRNA. These findings demonstrate that RBM27 plays a critical role in heart function by maintaining the normal alternative splicing of Tnnt2, highlighting its importance in maintaining heart health.
Atherosclerosis is the leading cause of cardiovascular disease worldwide, yet current therapies remain limited and often fail to fully prevent disease progression. This study integrates genome-wide association study data from the FinnGen R10 cohort and the UK Biobank for coronary atherosclerosis and carotid-dominant cerebral atherosclerosis to prioritize genetically supported candidate targets. Mendelian randomization (MR), summary-based MR, Steiger tests, and colocalization analyses are performed across multiple proteomic, transcriptomic, and methylation QTL datasets, followed by validation using public plaque transcriptomic/proteomic resources and single-center Western blotting. Candidate targets are further investigated through database mining, molecular docking, and phenome-wide association analyses to assess druggability signals and potential safety liabilities. In addition, a machine-learning model is trained using MR-prioritized genes to evaluate plaque-based transcriptomic classification performance, whereas immune and single-cell analyses are conducted to investigate cell-type-specific expression patterns. Following sensitivity analyses and false discovery rate (FDR) correction, 43 proteins are prioritized as genetically supported candidate targets, including 3 for carotid-dominant cerebral atherosclerosis and 40 for coronary atherosclerosis. Sixteen proteins demonstrate consistent support across multiple omics layers and analytical filters. Novel candidates, including PRSS22, SPINK1, ACP6, DUSP13, PELO, and PPP1R14A, are identified for further investigation. This multi-omics MR framework provides a prioritized list of candidate targets with supporting evidence of disease relevance while further functional and pharmacological studies are required to evaluate their therapeutic efficacy and safety.
Acute myeloid leukemia (AML) is maintained by a rare subpopulation of leukemic initiating cells, which drive disease progression, therapy resistance, and relapse. Transcription factor AP-2α, known for its role in tumor regulation, has an unclear function in leukemic initiating cells. Here, we found that low AP-2α expression correlated with poor AML prognosis, while high expression suppressed disease progression and improved survival. Functionally, AP-2α limited leukemic stem/initiating cell self-renewal and AML maintenance but was dispensable for normal hematopoiesis, as demonstrated using a Tfap2a conditional knockout model in hematopoietic stem cells. Moreover, loss of Tfap2a accelerated MLL-AF9 (MA9)-driven leukemogenesis in vivo, with knockout bone marrow exhibiting an expansion of leukemic granulocyte–monocyte progenitors, reflecting enhanced leukemia stem cell activity. Mechanistically, RNA-sequencing of Tfap2a-deficient cells revealed activation of inflammatory and stemness-related pathways, including JAK–STAT and TLR4 signaling. We further identified AP-2α as a direct transcriptional repressor of TLR4 by binding to its promoter, thereby exerting tumor-suppressive effects in AML-5 cells. Notably, the JAK2 inhibitor Fedratinib elevated AP-2α protein levels by attenuating STAT3 binding at the AP-2α promoter, positioning AP-2α as a downstream target of STAT3. Combining AP-2α overexpression with Fedratinib treatment or STAT3 knockdown synergistically inhibited AML-5 cell proliferation and leukemic stem cell self-renewal. These findings define a novel STAT3–AP-2α–TLR4 regulatory axis in AML and highlight AP-2α as a tumor suppressor that restrains leukemic stemness and disease progression. Therapeutic strategies that restore AP-2α expression or enhance its function—particularly in combination with JAK2 inhibition—may effectively target leukemic initiating cells in specific AML subtypes.
Post-translational modifications (PTMs) are enzymatic or chemical processes that dynamically regulate protein function by covalently attaching or removing specific chemical groups to amino acid residues. These modifications include classical types such as phosphorylation, ubiquitination, and acetylation. Due to the rapid advancement of proteomics and mass spectrometry technologies, novel acylation modifications, including succinylation, lactylation, crotonylation, and palmitoylation, have garnered attention in various research fields. These modifications are prevalent on key proteins, such as metabolic enzymes and histones, playing essential roles in processes such as energy metabolism, gene transcription, and signal transduction regulation. In oncology, metabolic reprogramming represents a hallmark of cancer progression, characterized by dysregulation in glycolysis, oxidative phosphorylation, fatty acid metabolism, and amino acid metabolism. PTMs orchestrate cellular metabolism through multifaceted mechanisms, including direct modulation of metabolic enzyme activity, alteration of metabolite flux, and rewiring of signaling networks. For instance, Ub ligase (E3) ubiquitin ligases selectively degrade rate-limiting metabolic enzymes via the ubiquitin‒proteasome system, thereby redirecting metabolic pathways. Notably, lactate serves not only as an energy substrate fueling the oncogenic Warburg effect but also as a metabolic precursor promoting histone lactylation modifications, which epigenetically reprogram oncogene expression. Current challenges in targeting PTMs include inadequate mechanistic understanding of emerging modifications, identification of cell-specific druggable targets, and complex crosstalk within PTM networks. This review uniquely dissects the bidirectional regulatory axis between PTMs, particularly acylation modifications, and tumor metabolic networks, providing novel therapeutic perspectives for clinical intervention.
