Complement factor D, also known as adipsin, is produced by adipose tissue, and the liver that links metabolic regulation with innate immunity. Despite its established systemic functions, the regulation of hepatic adipsin expression and its contribution to metabolic disease remain poorly defined. Hepatic adipsin expression was examined in liver biopsies from non-diabetic individuals and patients with type 2 diabetes (T2D), in murine models of type 1 diabetes (T1D) and T2D, during the fasted-to-fed transition, and in primary hepatocytes exposed to glucose. Translational regulation was assessed by glucose stimulation and pharmacological inhibition of mTOR signaling. Hepatocyte-specific adipsin knockdown was performed using liver-targeted shRNA to determine its metabolic function. We show that hepatic adipsin protein abundance is markedly increased in individuals with type 2 diabetes, and positively correlates with glycated hemoglobin, despite unchanged mRNA expression. Concordantly, hepatic adipsin protein levels were elevated in multiple murine models of hyperglycemia, including type 1 diabetes (T1D), type 2 diabetes (T2D), and following fasting–refeeding transitions. In cultured hepatocytes, glucose exposure induced a rapid, dose-dependent increase in adipsin protein without altering transcript abundance, demonstrating post-transcriptional regulation. Mechanistically, glucose stimulates adipsin translation via dephosphorylation of eukaryotic initiation factor 2α (eIF2α), and activation of the mammalian target of rapamycin, mediated by the 5′ untranslated region of Adipsin mRNA.Functionally, hepatocyte-specific depletion of adipsin impaired postprandial glucose tolerance, with reduced glucose uptake and a marked downregulation of glucose transporter type 2(GLUT2). These findings identify hepatic adipsin as a glucose-responsive translational target that couples nutrient availability to metabolic adaptation, revealingpreviously unrecognised regulation with potential relevance to diabetes pathogenesis.
CD47 is a major innate immune checkpoint molecule that interacts with signal regulatory protein α (SIRPα) to deliver a “don’t eat me” signal and restrain macrophage-mediated phagocytosis. Accumulating evidence indicates that dysregulated CD47 expression is associated with immune escape, treatment resistance, and adverse clinicopathological features in several digestive system cancers, although the strength of these associations varies across tumor types. This narrative review provides an integrative overview of CD47 structure, ligand interactions, signaling and immune-regulatory functions, and summarizes reported expression patterns and available evidence regarding regulatory mechanisms and relevant mechanistic contexts in esophageal, gastric, colorectal, hepatocellular, pancreatic, and biliary tract cancers. We further review therapeutic strategies targeting the CD47–SIRPα axis, including anti-CD47 antibodies, SIRPα fusion proteins, bispecific antibodies, and emerging cell-based and nanotechnology-based platforms, with particular attention to recent clinical developments. Finally, we critically discuss translational challenges, including hematologic toxicity and antigen sink, assay standardization and biomarker selection, resistance mechanisms, optimization of combination regimens, and the need for prospective validation of hypothesis-generating biomarker signals. By integrating recent 2025–2026 clinical developments with mechanistic and engineering advances, including lessons from unsuccessful or discontinued clinical programs, this review provides a balanced perspective on the opportunities and remaining barriers to the clinical translation of CD47-directed therapy in digestive system cancers.
Despite the promise of immune checkpoint inhibitors (ICIs) for gastric cancer (GC) treatment, limited cytotoxic T cell infiltration remains a major barrier to therapeutic efficacy. This study investigates whether targeting HEAT repeat containing 1 (HEATR1) can induce immunogenic PANoptosis to enhance anti-tumor immunity. Bioinformatics analysis of TCGA-STAD cohort, syngeneic mouse models, and patient-derived organoids (PDOs) were employed to assess HEATR1 function. Mechanistic studies examined STAT1/IRF1 signaling, PANoptosis markers, and dendritic cell (DC) activation. Therapeutic efficacy was evaluated in combination with anti-PD1 immunotherapy. HEATR1 expression inversely correlated with CD8+ T cell infiltration in GC tissues and was associated with advanced tumor stage and lymph node metastasis. HEATR1 knockdown suppressed tumor growth in immunocompetent but not T cell-deficient mice, demonstrating immune-dependency. Mechanistically, HEATR1 deficiency stabilized STAT1 by inhibiting proteasome-mediated degradation, thereby sensitizing GC cells to IFN-γ-induced PANoptosis through STAT1/IRF1 signaling activation. This inflammatory cell death released damage-associated molecular patterns, which promoted DC maturation and cross-priming of CD8+ T cells. The resulting IFN-γ secretion established a positive feedback loop amplifying tumor cell PANoptosis. PDO models confirmed that HEATR1-silenced organoids exhibited enhanced PANoptosis and DC-mediated CD8+ T cell expansion. HEATR1 knockdown synergized with anti-PD1 therapy to significantly inhibit tumor progression. HEATR1 deficiency enhances GC cell sensitivity to IFN-γ-mediated PANoptosis via STAT1/IRF1 pathway activation, creating an immunogenic tumor microenvironment that potentiates ICI efficacy. These findings identify HEATR1 as a promising therapeutic target for improving GC immunotherapy outcomes.
Sepsis is a life-threatening systemic inflammatory syndrome frequently complicated by acute lung injury (ALI), which markedly increases mortality. Although caspase-1 is well known for its intracellular functions, its extracellular release and pathological role remain unclear. We recently identified cleaved extracellular caspase-1 (p20) (eCasp-1) as a novel damage-associated molecular pattern released via gasdermin D (GSDMD) pores. Furthermore, we developed a novel 16-amino-acid peptide, compound 16 (C16), designed to specifically disrupt the interaction between eCasp-1 and toll-like receptor 4 (TLR4). In the present study, we aimed to elucidate the dynamic release of eCasp-1 during sepsis and to evaluate the therapeutic potential of C16 for attenuating sepsis-induced ALI and improving survival. Sepsis was induced in mice by cecal ligation and puncture (CLP), and eCasp-1 levels were measured in plasma and peritoneal lavage fluid by Western blot and ELISA assays with or without injection of disulfiram, a GSDMD inhibitor. To evaluate therapeutic efficacy, CLP mice received intraperitoneal injection of vehicle or C16, and systemic inflammation, lung injury, and survival were assessed. We found that eCasp-1 time dependently increased in the plasma and peritoneal lavage fluid in septic mice. We demonstrated that eCasp-1 release during sepsis is associated with GSDMD-dependent membrane permeabilization, as disulfiram markedly reduced its levels in the blood and peritoneal lavage fluid. In septic mice, treatment with C16 significantly reduced systemic inflammatory cytokines and organ injury markers, attenuated ALI, and improved lung histopathological injury. Importantly, C16 treatment significantly improved the survival rate after sepsis. eCasp-1 acts as a key extracellular mediator of inflammatory amplification that drives ALI in sepsis. Targeting eCasp-1 with C16 represents a promising therapeutic strategy to mitigate inflammation and ALI and improve survival in sepsis.
Urinary extracellular vesicles (uEVs) have emerged as promising non-invasive molecular carriers for biomarker discovery, yet the physiological variability and tissue-associated characteristics of uEV RNA cargo in healthy individuals remain poorly defined. This knowledge gap limits the interpretation, normalization, and clinical translation of uEV-based transcriptomic studies. Here, we performed a longitudinal RNA-sequencing analysis of uEVs from 12 healthy donors, of whom six contributed complete longitudinal sample sets, to establish a molecular reference framework for physiological uEV transcriptomes. We systematically characterized inter- and intra-individual variation in uEV RNA cargo and found substantial transcriptomic heterogeneity despite relatively stable extracellular vesicle secretion levels over time. A conserved set of highly expressed genes was significantly enriched in ribosomal function and oxidative phosphorylation, indicating their role in fundamental cellular maintenance. Importantly, we identified 12 protein-coding genes that showed consistently low expression variance both across individuals and within individuals over time. Cross-dataset analyses using independent external and pan-cancer datasets further supported their potential utility as candidate reference transcripts for uEV RNA studies. Computational tissue deconvolution inferred predominant kidney- and bladder-associated transcriptomic signatures, while cell-type enrichment analysis showed relatively high enrichment scores for smooth muscle cells and mesenchymal stem cells. Together, this study defines the physiological landscape of healthy uEV transcriptomes, delineates key sources of biological variation, and provides candidate reference transcripts and tissue-associated molecular profiles to support the standardization and translational application of uEV-based molecular biomarker research.
Acute kidney injury (AKI) from renal ischemia–reperfusion (IR) injury is a major cause of acute organ dysfunction with significant morbidity and mortality. Critically, up to 50
Diabetic kidney disease (DKD) is a leading cause of end-stage renal disease, yet the immune mechanisms contributing to early-stage renal injury remain incompletely understood. This study investigates the association between B-cell dynamics and renal injury in early DKD. Here, we performed single-cell RNA sequencing (scRNA-seq) on bone marrow (BM) and kidneys from 16-week-old db/m and db/db mice, combined with multi-omics data analysis, as well as anti-CD20 antibody-mediated B cell depletion experiments, to characterize B-cell state changes in the context of early-stage DKD. We observed aberrant B-cell differentiation in the BM of DKD mice, with a significantly increased proportion of activated Cxcr5⁺ B cells compared to controls. The Cxcl13-Cxcr5 signaling pathway was markedly upregulated in DKD kidneys, with elevated Cxcl13 expression specifically localized to the thick ascending limb (tAL). Cell–cell communication analysis revealed that tAL-B-cell interactions were prominently connected via this axis. Computational perturbation analysis of CXCR5 in mouse and human B cells highlighted its potential association with activation and differentiation signatures. Furthermore, anti-CD20-mediated B-cell depletion significantly attenuated renal injury in DKD mice, and transcriptomic profiling suggested that this protective effect was accompanied by restoration of renal metabolic pathways. Collectively, our findings suggest that expansion of BM Cxcr5⁺ B cells is closely associated with renal injury in early-stage DKD, with the CXCL13-CXCR5 axis identified as a potential mediator of B-cell accumulation. B-cell depletion ameliorates renal injury, suggesting that immunomodulation of B cells may represent a promising therapeutic avenue, although direct causal validation requires further experimental investigation.
Critical limb ischemia is the end stage of lower extremity peripheral artery disease (PAD) with few available pharmacological and endovascular approaches. Stem cell-based therapy represents a promising therapeutic strategy for angiogenesis; however, its clinical benefits have not yet met expectations. Tissue acidosis is a central challenge in stem cell transplantation, and poor cell survival and function of the transplanted cells caused by acidosis-mediated injury limit the therapeutic potential. This study aimed to determine whether GPR65, a proton-sensitive G protein-coupled receptor, improves adipose-derived stem cells (ADSCs) survival in acidic environments and to elucidate the underlying mechanisms. GPR65 expression in ADSCs exposed to acidic conditions and in ischemic muscles were analysed. Subsequently, lentivirus-induced GPR65-overexpressing ADSCs were constructed and subjected to functional and angiogenic assays under low pH conditions. The function of these cells was explored using a mouse hindlimb ischemia model with transplantation of the cells or control medium into the ischemic muscles. Metabolic alterations, blood perfusion recovery, vascular regeneration and transplanted cell survival in the ischemic area were measured during a 14-day follow-up period. Additionally, we investigated the pathways induced by GPR65 using transcriptomic sequencing, proteomic analyses, western blot, and quantitative reverse transcription polymerase chain reaction. Finally, western blot analyses were carried out to determine the role of endogenous GPR65 for adaptation to acidic stress in GPR65 knock-down ADSCs by shRNA. We observed significant changes in GPR65 expression in response to acidic and ischemic conditions, both in vitro and in vivo. Genetic overexpression of GPR65 in ADSCs induced protective effects on cell survival, cell proliferation, and dysregulation of mitochondrial dynamics in response to acidosis. Importantly, GPR65 overexpression promoted the angiogenic potential, VEGF-A and HGF secretion. Remarkedly these effects resulted in the improved limb salvage, blood reperfusion, vascular regeneration and retained ADCS in ischemic tissues via the accelerated phosphorylation of the Akt and ERK1/2 pathways. In contrast, GPR65 knock-down impaired VEGF-A expression, Akt and ERK1/2 activation in cultured ADSCs under low pH condition. Our study identified GPR65 as a therapeutic target for protection of transplanted stem cells against acidosis-mediated injury. These results suggest that genetically engineered ADSCs expressing GPR65 may be an innovative strategy for the treatment of ischemic vascular diseases.
Chronic stress is a major risk factor for insomnia, yet the molecular mechanisms linking stress-induced gut dysbiosis and bile acid (BA) metabolism to circadian disruption remain poorly understood. A rat model of chronic unpredictable mild stress combined with modified multiple platform sleep deprivation was established. Sleep-wake patterns were assessed by PiezoSleep monitoring. Anxiety- and depression-like behaviors were evaluated using the open field test, elevated plus maze, and tail suspension test. Spatial memory was tested with the Morris water maze. Gut microbiota was profiled via 16S rRNA sequencing. Serum total BAs were measured by enzymatic cycling, and hypothalamic BA metabolites were quantified by targeted UPLC-MS/MS. The BA sequestrant cholestyramine was administered to evaluate therapeutic effects. To test BA sufficiency, a separate cohort received oral deoxycholic acid (DCA) for three days with subsequent sleep and molecular assessments. Model rats showed marked sleep loss, a reversed day/night sleep ratio, anxiety- and depression-like behaviors, and cognitive deficits. Their gut microbiota exhibited reduced Firmicutes along with increased Bacteroidetes and Proteobacteria. Serum total BAs and hypothalamic levels of deoxycholic acid were significantly elevated. This was accompanied by upregulation of TGR5, ERK, and CK1ε, depletion of nuclear PER2, and disrupted the rhythmic secretion of Clock and Bmal1. Cholestyramine lowered BA loads, restored PER2 nuclear localization, normalized the rhythmic gene expression of Clock and Bmal1, and reversed all behavioral and sleep abnormalities. Importantly, DCA alone phenocopied the core sleep, molecular, and circadian disturbances observed in the model rats. BA overload, especially DCA, drives circadian and sleep disturbances via the hypothalamic TGR5-ERK-CK1ε-PER2 pathway. BA sequestering represents a promising strategy for treating insomnia with comorbid negative emotional states.
Members of the Wiskott-Aldrich syndrome protein (WASP) family orchestrate cytoskeletal reorganization that modulates B-cell receptor (BCR) signaling and B-cell fate decisions. WHAMM, a WASP-family nucleation-promoting factor member that associates with actin, membranes and microtubules, has not been functionally characterized in B cells. To investigate the role of WHAMM in B-cell development and function, we analyzed a conditional mouse model in which Whamm was deleted in the B-cell lineage. WHAMM-deficient mice exhibited altered splenic B-cell composition, characterized by an accumulation of splenic transitional B cells and a reduction of follicular B cells. Meanwhile, WHAMM deficiency altered the spatial organization and kinetics of proximal BCR signaling, and modified the dynamics of BCR-induced actin remodeling. However, WHAMM-deficient B cells showed largely preserved BCR internalization, antigen presentation, PI3K-AKT-mTOR signaling, ROS production, and mitochondrial membrane potential. Together, this work indicates that WHAMM helps shape splenic B-cell populations and regulates proximal BCR signaling and actin dynamics, while several downstream functional responses remain largely preserved in this study.
Sepsis-associated acute kidney injury (SA-AKI) is a leading cause of mortality in critically ill patients, involving complex interactions between metabolic reprogramming and excessive inflammation. β-hydroxybutyrate (BHB), an endogenous ketone body, has emerged as a regulator of post-translational modifications through inducing β-hydroxybutyrylation (Kbhb). However, the role of BHB in SA-AKI remains unclear. A multi-system research strategy integrating clinical samples, animal models, and cellular experiments was employed. The clinical correlation between BHB and renal function was assessed in SA-AKI patients. SA-AKI mouse model was established using CLP, followed by intervention with either a ketogenic diet or exogenous BHB administration. Renal function, inflammatory factors, and global Kbhb modifications in kidney tissues were assessed. The effects of BHB were further validated in LPS-stimulated HK-2 cells and mouse primary renal tubular epithelial cells. Proteomics combined with Kbhb modification profiling was employed to screen key target proteins. Techniques including Co-IP, site-directed mutagenesis, and customized antibodies were utilized to identify Kbhb modification on the target protein high mobility group box 1 (HMGB1) and to determine its critical modification sites. Co-IP coupled with mass spectrometry was applied to screen for HMGB1-interacting proteins. Clinical analysis demonstrated that elevated serum BHB levels in SA-AKI patients correlated with improved renal function recovery and showed prognostic value for renal recovery (AUC = 0.819). In vivo and in vitro experiments demonstrated that BHB intervention significantly improved renal function in CLP mice and attenuated LPS-induced cell injury. Mechanistic investigations revealed that BHB enhanced HMGB1-Kbhb modification through a p300/CBP-dependent mechanism, with lysine 90 (K90) identified as a functionally important modification site. This modification inhibited HMGB1 nuclear-cytoplasmic translocation, thereby reducing cytoplasmic HMGB1 availability and attenuating its interaction with GSDME, resulting in suppression of downstream inflammatory mediators including IL-1β and IL-18. This study demonstrates that BHB may serve as a potential prognostic biomarker in SA-AKI. Mechanistically, BHB protects against renal injury partially through p300/CBP-mediated HMGB1-K90bhb modification, which inhibits HMGB1 nuclear-cytoplasmic translocation and its interaction with GSDME, thereby suppressing inflammatory pyroptotic responses. These findings reveal a novel mechanism by which BHB regulates SA-AKI and provide potential therapeutic targets for its treatment.
Metabolic dysfunction-associated steatohepatitis (MASH) is a leading cause of liver-related morbidity and mortality. The current interventions are limited, underscoring the need for novel mechanism-based therapies. Protein tyrosine phosphatase 1B (PTP1B) regulates phosphotyrosine signaling and hepatic metabolism, but its role in MASH remains incompletely understood. To elucidate the impact of modulating PTP1B expression in MASH, we used mice with hepatocyte-specific PTP1B disruption in the fast-food diet (FFD) model of the disease and then monitored alterations in inflammation, steatosis, and fibrosis. In this study, we observed elevated hepatic PTP1B expression in the FFD mouse model of MASH and in liver biopsies from MASH patients. PTP1B deficiency ameliorated FFD-induced hepatic injury and inflammation as evidenced by lower alanine aminotransferase, Tnf and Il1b, and NFκB phosphorylation. Additionally, PTP1B deficiency partially rebalanced the hepatic and systemic lipid dysregulation under the FFD-fed state. Notably, PTP1B deficiency alleviated the hepatic fibrosis induced by the prolonged FFD regimen. Moreover, mice with hepatic PTP1B deficiency exhibited improved glucose control under FFD independently of body weight changes. Mechanistically, PTP1B deficiency was associated with enhanced hepatic insulin signaling and decreased oxidative stress. Collectively, these findings establish that PTP1B deficiency in hepatocytes modulates several pathways implicated in MASH and confers improvements that may curtail disease progression. Further investigation is warranted into targeting this phosphatase as part of the armamentarium in the therapeutic landscape for MASH.
Sepsis-associated encephalopathy (SAE) is a severe refractory neurological complication occurring in up to 70
Mutations or reduced expression in glycine N-methyltransferase (GNMT) has been linked to liver diseases. Methotrexate (MTX) is commonly prescribed for the treatment of human rheumatic diseases. We previously demonstrated that MTX selectively inhibits the partitioning of mitochondria derived formate pathways, including glycine cleavage system (GCS). We also demonstrated that GNMT expression is essential for methyl group supply, intracellular folate homeostasis and MTX toxicity. We tested the hypothesis that GNMT regulates the metabolic response to low-dose methotrexate by altering mitochondrial one-carbon metabolism, thereby influencing glycine-derived one-carbon partitioning, DNA methylation, and central carbon metabolism. Metabolic alterations of mitochondrial one carbon metabolism and TCA cycle were investigated in liver derived cell-lines with/without human GNMT expression, as well as in wild-type (WT, Gnmt+/+) and GNMT knockout (KO, Gnmt-/-) mouse models treated with MTX using stable isotopic tracers and GC/MS. MTX inhibited deoxythymidylate (dTMP) synthesis from mitochondria derived formate in both WT and Gnmt-/- mice bone marrow. Deletion of Gnmt in mice decreased enrichment in 5-methyl-2′-deoxycytidine (5-mdC) but not dTMP synthesis from GCS using [2-13 C] glycine tracer. Interestingly, MTX inhibited 5-mdC enrichments in Gnmt+/+ but promoted that in Gnmt-/- in the bone marrow, indicating gene-drug interactions in GCS activity. MTX decreased liver pyruvate concentrations in both Gnmt+/+ and Gnmt-/-, whereas MTX increased plasma citrate concentration in Gnmt+/+ but not in Gnmt-/-. MTX suppressed liver alpha-ketoglutarate but increased malate concentrations in Gnmt+/+ but not Gnmt-/-. The present study provides evidence on the interactions between MTX and GNMT function and provides new insights on how this essential gene may affect mitochondria derived formate dependent pathways and central carbon metabolism during MTX therapy. In patients taking long-term MTX therapy, genetic factors such as hepatic GNMT function should be taken into consideration.
Sepsis is a life-threatening condition with high mortality, in which sepsis-induced immunosuppression—characterized by CD4+ T cell dysfunction and apoptosis—worsens clinical outcomes. The mechanistic link between neutrophil extracellular traps (NETs) and CD4+ T cell fate in sepsis remains poorly elucidated. We integrated plasma analysis from 50 sepsis patients and 31 healthy controls, a murine cecal ligation and puncture (CLP) sepsis model, and in vitro assays with Jurkat cells and primary CD4+ T cells. We investigated the effects of NETs on CD4+ T cell calcium signaling and mitochondrial function, and verified the therapeutic efficacy of DNase I combined with the mitochondrial-targeted antioxidant mitoTEMPO. Circulating NETs were significantly elevated in sepsis patients, positively correlated with disease severity (SOFA score) and negatively correlated with peripheral CD4+ T cell counts. NETs disrupted intracellular calcium homeostasis by inhibiting store-operated calcium entry, suppressing calcineurin activity and NFAT nuclear translocation, thus impairing T cell activation and IL-2 production. Additionally, NETs induced mitochondrial dysfunction via excessive mitochondrial reactive oxygen species (mtROS) production and reduced mitochondrial calcium uptake, leading to loss of mitochondrial membrane potential, structural damage, and subsequent CD4+ T cell apoptosis. In CLP mice, monotherapy with either DNase I or mitoTEMPO partially attenuated CD4+ T cell injury, while the combination significantly improved 7-day survival compared with monotherapy or vehicle, reduced plasma organ injury markers, and alleviated splenic lymphocyte apoptosis. The NETs-mtROS axis represents an important pathway driving CD4+ T cell death in sepsis. Dual targeting of NETs and mitochondrial oxidative stress holds promising therapeutic potential for ameliorating sepsis-induced immunosuppression.
Reprogramming of cellular metabolism in cancer leads to changes in the activity of metabolic coenzymes NAD(P)H and FAD which can be used as markers of tumorigenesis and metastasis. NAD(P)H and FAD form coupled redox pair and regulator of mitochondrial energy metabolism. Since NAD(P)H and FAD are endogenous and auto fluorescent, the coupled redox pair can hence be exploited as a reporter for metabolic activity in tumor microenvironment. We have developed a 2P-FLIRR assay (2-photon Fluorescence Lifetime based Redox Ratio), a sensitive metabolic optical biomarker for tumor diagnosis in prostate cancer (PCa) patients’ tissue sections. We have imaged and used our novel 2P-FLIRR metric which is the ratio of the enzyme-bound fractions of NAD(P)H and FAD to evaluate PCa patients’ surgically resected tissue sections. These were PCa adenocarcinomas with different Gleason grades. In comparison with conventional H E histopathology, our 2P-FLIRR assay showed the potential to distinguish tumor-enriched regions from normal prostate tissue in unstained frozen patient tissue sections. Lower FLIRR values were observed to correspond to tumor versus higher FLIRR values to normal prostate. This pilot feasibility study demonstrates that 2P-FLIRR detects metabolic contrast between prostate cancer and normal prostate tissue in frozen human patient tissue sections. Our study identifies for the first time quantitative 2P-FLIRR as a potential sensitive diagnostic optical biomarker for PCa.
Cadmium (Cd) is a pervasive environmental heavy metal linked to various chronic pathologies; however, its specific role and underlying molecular mechanisms in osteoarthritis (OA) pathogenesis remain poorly characterized. We performed a cross-sectional analysis using the NHANES database (2001–2018) to evaluate the association between blood Cd levels and OA risk. Hub targets were identified by integrating the CTD and GEO databases through network toxicology and machine learning algorithms. Single-cell RNA sequencing (scRNA-seq) was employed to resolve the cellular localization and dynamic shifts of these targets. Causal relationships were substantiated via drug-target Mendelian randomization (MR) analysis. Findings were further corroborated through molecular docking, 100-ns molecular dynamics (MD) simulations, and an independent retrospective clinical cohort consisting of 180 OA patients and 400 cervical spondylosis controls, in which peripheral blood inflammatory markers were evaluated for clinical validation. Cross-sectional analysis revealed a significant positive association between blood Cd concentrations and OA prevalence, with a robust dose-response relationship (OR per log-unit = 1.64, P < 0.001). Multi-omics integration identified APP (Amyloid Precursor Protein) as a pivotal Cd-associated hub gene. scRNA-seq localized APP overexpression predominantly within fibrocartilage cells (FC), with notable upregulation across OA-derived chondrocyte subpopulations. While MR analysis suggested an inherent protective causal effect of APP against OA risk, this physiological role appears disrupted by the Cd-induced inflammatory milieu, where aberrant APP processing likely promotes cartilage matrix degradation. Retrospective clinical validation further demonstrated systemic immune dysregulation in OA patients, with inflammatory markers including WBC, monocytes, SII, and NLR showing robust diagnostic performance (AUC > 0.9), thereby providing clinical evidence supporting the involvement of the APP-associated immune-inflammatory axis. Furthermore, MD simulations suggested a possible binding mode between NAC and APP with modest affinity, providing preliminary structural insights that warrant further experimental validation. This study systematically elucidates the molecular landscape through which Cd exposure drives OA progression via the APP-mediated immune-inflammatory axis. These findings provide a novel theoretical framework for early screening and targeted therapeutic strategies in populations at high risk of environmental heavy metal exposure.
Aberrant succinate accumulation functions as a potent metabolic danger signal in various inflammatory diseases. However, the specific contribution of the succinate-GPR91 signaling axis to the pathogenesis of renal fibrosis remains incompletely defined. Succinate levels were analyzed in kidney tissues from patients with obstructive nephropathy and mice with unilateral ureteral obstruction (UUO). The impact of succinate on renal fibrosis was evaluated using exogenous succinate administration and pharmacological inhibition with dimethyl malonate (DMM). Mechanistic studies employed Gpr91-knockout mice, NLRP3-knockout mice, and cultured macrophages to dissect the downstream signaling pathways linking metabolic alterations to innate immunity. We observed significantly elevated succinate levels in fibrotic kidneys from both patients and UUO mice, which correlated positively with disease severity. Functionally, exogenous succinate markedly exacerbated renal inflammation and fibrosis, whereas pharmacological inhibition with DMM attenuated these pathological changes. Mechanistically, we demonstrated that succinate mainly activates its receptor GPR91 on macrophages to trigger NLRP3 inflammasome assembly and IL-1β secretion, a pro-fibrotic cascade effectively abolished by genetic ablation of Gpr91 or NLRP3 in vivo, or by their pharmacological blockade in vitro. This study establishes the succinate-GPR91 axis as a pivotal metabolic driver of renal fibrosis, likely primarily through macrophage-mediated NLRP3 inflammasome activation. Targeting this pathway represents a promising therapeutic strategy for interfering with the progression of chronic kidney disease.
Diabetic cardiomyopathy (DCM) is defined by progressive cardiac dysfunction driven by myocardial ATP depletion, where mitochondrial electron transport chain (ETC) Complex I dysfunction acts as a critical factor. Protein arginine methyltransferase 5 (PRMT5) maintains cardiac homeostasis, yet its function in DCM and association with Complex I remain elusive. This study aimed to investigate the function, key substrate, and mechanism of PRMT5 in DCM, and evaluate serum PRMT5 as a potential biomarker for DCM. Gain- and loss-of-function experiments of PRMT5 were conducted to explore the function of PRMT5 in DCM. IP-MS proteomics and post-translational modification analysis were applied to identify the substrates of PRMT5 and their modified sites. By employing ELISA assay, serum levels of PRMT5, lactate, and lactate/pyruvate (L/P) ratio were measured in DCM patients, and the association between serum PRMT5 level and hospital readmission risk was analyzed. PRMT5 overexpression protected against DCM pathogenesis, while its knockdown or inhibition exacerbated disease progression. PRMT5 mediated symmetric di-methylation (SDMA) of Ndufs2 at R118 to prevent its ubiquitin-proteasomal degradation and preserve mitochondrial Complex I function. DCM patients had significantly lower serum PRMT5, which correlated positively with serum lactate and L/P ratio and was associated with higher hospital readmission risk. Our findings unveil a novel PRMT5/Ndufs2 regulatory axis where arginine methylation maintains bioenergetic capacity of Complex I through methylation-ubiquitination crosstalk. PRMT5 shows potential as a therapeutic target and biomarker for DCM, which may aid the establishment of innovative diagnostic and treatment frameworks for DCM pending further translational validation.
Cardiovascular diseases (CVDs) remain the leading cause of global mortality, perpetuated by pathological remodeling refractory to current pharmacotherapy. Recent single-cell atlasing has identified fibroblast activation protein (FAP) as a convergent marker of pathogenic stromal cells across disparate cardiovascular pathologies. In cardiac fibrosis, FAP demarcates myofibroblasts driving extracellular matrix (ECM) deposition, whereas in atherosclerosis, it marks modulated smooth muscle cells (modSMCs) mediating plaque instability. This review synthesizes emerging evidence to establish a precision cardio-immunology framework. We first characterize FAP not merely as a serine protease, but as a multifaceted integrative node aligned with TGF-β and PI3K/AKT pathways. We then systematically compare the expanding repertoire of FAP-targeted modalities, ranging from cytotoxic CAR T cells and transient bispecific engagers (BiTEs) to tolerogenic dendritic cells, and propose that therapeutic persistence must align with disease kinetics. Specifically, we suggest the use of durable CAR T cells in chronic fibrosis and transient BiTEs for acute plaque stabilization. Finally, we address translational challenges, including FAP’s context-dependent effects, and discuss logic-gated switches to improve the therapeutic index. This review offers a kinetic-matching roadmap for cardiovascular remodeling beyond conventional symptomatic relief.
