Alzheimer's disease (AD) is the most prevalent neurodegenerative disorder associated with dementia, progressive neuronal loss, extracellular amyloid-β (Aβ) and intracellular hyperphosphorylated tau deposition. Currently, no curative therapies are available for this condition. Beyond these features, AD pathogenesis is associated with neuroinflammation, which is thought to be primarily driven by microglial cells, and has evolved as an important contributor to AD pathogenesis over the past decade. Although microglia cells play a central role in neuroinflammation, they are also a highly heterogeneous population existing in distinct transcriptional states that can be either beneficial or detrimental to disease progression. Importantly, microglial activation and the ensuing neuroinflammatory milieu do not operate independently of the systemic immune system. The longstanding view of the brain as an immune-privileged organ has been fundamentally revised, with increasing evidence demonstrating that the crosstalk between brain-resident and circulating peripheral immune cells plays a pivotal role in AD pathogenesis. Peripheral immune cells, recruited in the central nervous system in response to Aβ and tau pathology, actively modulate the neuroinflammatory environment. While CD4+ and CD8+ T cells have been extensively investigated in this context, the contribution of B cells to AD remains poorly understood. Here, we comprehensively review the phenotypic and functional alterations of B cells in AD, integrating evidence from experimental models and human studies, to evaluate whether B cells constitute an underappreciated component of the adaptive immune response in AD and whether they represent a compelling immunotherapeutic target. We also highlight key unresolved questions and propose future research directions to guide the field towards a deeper mechanistic understanding of B cell biology in AD.
BACKGROUND:Mucosal-associated invariant T (MAIT) cells are innate-like T cells that respond rapidly to microbial metabolites presented by MR1. Patients with aplastic anemia (AA) are prone to bacterial and fungal infections, but the MR1-related effector responses of MAIT cells in AA remain unclear. METHODS:Peripheral blood mononuclear cells from 27 patients with AA and 29 healthy individuals were stimulated with fixed Escherichia coli for 2, 3, 6, or 12 h, with or without MR1 blockade. CD8+ MAIT cell activation, cytokine production, degranulation, CD69 expression, and polyfunctional profiles were assessed by flow cytometry. RESULTS:CD8+ MAIT cells from patients with AA showed higher CD69 expression under unstimulated conditions, suggesting a basal activation state. After fixed E. coli stimulation, CD8+ MAIT cells from patients with AA displayed enhanced early effector responses compared with those from healthy individuals, characterized by increased TNF production, CD107a expression, and polyfunctional subset frequencies, particularly CD107a+TNF+ populations. These enhanced responses were most pronounced at 6 h after stimulation. MR1 blockade markedly reduced E. coli-induced cytokine production and CD107a expression in CD8+ MAIT cells, supporting an important contribution of MR1-dependent signaling to these responses. CONCLUSIONS:In patients with AA, CD8+ MAIT cells display markedly enhanced effector functions and polyfunctional responses upon E. coli stimulation. These findings indicate that riboflavin metabolism-related bacterial infection in patients with AA can induce functional disorders of CD8+ MAIT cells via the MR1-TCR pathway.
Autoreactive T and B cells recognizing tissue-associated self-antigens are tolerized in the periphery, where dendritic cells (DCs) initiate the inactivation of autoreactive T cells. Here, we generated a mouse model in which a neo-self-antigen is expressed in the epidermis and examined interactions between DCs and antigen-specific CD4 T cells, as well as between CD4 T cells and B cells under tolerant conditions. We found that one of the tumor necrosis factor receptor superfamily (TNFRSF) molecules, herpesvirus entry mediator (HVEM), in CD4 T cells performs two key functions: it promotes regulatory T cell (Treg) expansion in response to epidermal antigen and suppresses B cell activation by sending inhibitory signals. HVEM-deficient Tregs failed to respond to self-antigen-loaded migratory DCs from the skin, whereas HVEM-deficient CD4 T cells enhanced B cell activation, leading to increased IgG1+ B cells. These findings demonstrate that HVEM in CD4 T cells contributes to peripheral tolerance to tissue-associated self-antigens by promoting Treg expansion and restraining B cell responses.
The common marmoset (Callithrix jacchus) is a valuable non-human primate model organism with a long history of use in biomedical research, including investigating diseases with an immune component. However, prior to this effort, there has been a lack of sufficiently validated tools to quantify inflammatory markers in the common marmoset using a multiplex approach. We provide a cross-species reactivity validation of a human-specific multiplex analysis strategy that allows for the assessment of 20 distinct inflammatory analytes in a small volume of plasma isolated from common marmoset blood. We used this novel approach to perform an assessment of the impact of sex as a biological variable on a subset of these inflammatory analytes. We found that endogenous plasma levels of the following analytes are not significantly different between female and male marmosets: CRP, ICAM-1, VCAM-1, IL-13, IL-8, MIP-1β, IFN-g, IL-4, VEGF-A, FLT-1, and bFGF. These findings demonstrate the utility of our validated method for quantifying marmoset inflammatory markers.
Purpose Ulcerative colitis (UC) pathogenesis involves neutrophil extracellular trap (NET) formation and intestinal barrier collapse. High mobility group box 1 (HMGB1) acts as a critical “alarmin,” triggering neutrophil activation via the Toll-like receptor 4 (TLR4) axis. We investigated whether Astragalus polysaccharides (APS) could disrupt this “HMGB1-NETs” vicious cycle to treat UC. Methods Severe colitis was induced in SD rats using 2,4,6-trinitrobenzene sulfonic acid (TNBS). Rats received APS (200, 400, 800 mg/kg), DNase I (to degrade NETs), or “APS + exogenous HMGB1” (functional rescue). Disease severity was assessed via Disease Activity Index (DAI) and histopathology. NETs were quantified by immunofluorescence (Cit-H3/MPO/PAD4 co-localization) and Western Blot. Results TNBS induction was associated with marked NETosis, HMGB1 nucleocytoplasmic redistribution, and redox dysregulation. DNase I treatment supported the pathogenic contribution of NETs in this model. APS (800 mg/kg) ameliorated colitis, reduced NET-associated markers, and suppressed HMGB1/TLR4 signaling in colon tissue. Exogenous HMGB1 attenuated APS-mediated protection and reactivated NETosis-associated inflammatory changes. APS also partially restored redox homeostasis by normalizing catalase activity and improving SOD/GST activities. Conclusion APS ameliorates experimental UC in association with suppression of HMGB1/TLR4-linked NETosis and restoration of redox balance. These findings support APS as a potential regulator of NET-associated inflammation, while direct neutrophil-level and translational validation remains needed.
BACKGROUND:Lung cancer (LC) is a leading cause of cancer-related death. Microwave ablation (MWA) is a promising local therapy, but its impact on systemic immunity remains unclear. METHODS:In this exploratory pilot study, paired peripheral blood samples from two LC patients pre- and post-MWA were analyzed by single-cell RNA sequencing (scRNA-seq). Cell composition, functional states, and intercellular communication were investigated. The expression levels of cytotoxic factors including GZMB, TNF-α, and IFN-γ in CD8+ T cells derived from PBMCs were determined via RT-qPCR and ELISA assays. RESULTS:scRNA-seq identified 9 immune cell types. Post-MWA, monocytes and NKT cells increased. Functional changes included enhanced T cell cytotoxicity, activated pro-inflammatory monocytes, and anti-tumor neutrophil differentiation. Cell communication analysis highlighted enriched LGALS9-CD45 and RETN-CAP1 interactions between T cells and monocytes/neutrophils. In vitro cellular assays revealed that the expression of cytotoxic factors (GZMB, TNF-α, and IFN-γ) in CD8+ T cells was significantly upregulated following MWA treatment. CONCLUSION:This pilot study provides preliminary single-cell evidence suggesting how MWA remodels the immune landscape in LC, however, these findings require further validation in larger cohorts.
BACKGROUND:During sepsis, multiple pathogenic factors - including hyperinflammatory responses, gut dysbiosis, and immune cell dysfunction - collectively compromise intestinal barrier integrity, thereby exacerbating disease progression. In this research, we have elucidated the in vivo therapeutic efficacy of Jiawei Taohe Chengqi Decoction (JTCD) in ameliorating sepsis-induced intestinal injury and elucidated its underlying molecular mechanisms. METHODS:The septic mice model was established to assess the pharmacological impact of JTCD and Taohe Chengqi Decoction (THCQD) in vivo. Network pharmacology analysis of the active components of JTCD was performed. Intestinal permeability was assessed by measuring FITC-Dextran flux, while tissue morphology and pathology were examined by H&E staining. The level of IL-6, IL-1β, TNF-α DAO, D-LA, I-FABP, IL-10 and IL-4 were evaluated by the corresponding ELISA kit. The expression of ZO-1, Claudin-1, Notch1, Jagged1 and HES1 was assessed by western blot. Immunofluorescence was applied to assess the expression of F4/80, iNOS, CD206 and Notch1. The cell counting kit-8 (CCK-8) was employed to evaluate the viability. Flow cytometry was applied to quantify the populations of F4/80 + CD86+ and F4/80 + CD163+. TEER assay was performed to assess the integrity of intestinal barrier. RESULTS:JTCD ameliorated intestinal barrier dysfunction in septic mice by reducing permeability, mitigating histopathological damage, lowering serum injury biomarkers, and upregulating tight junction proteins. JTCD exerted therapeutic effects by modulating the Notch signaling pathway and intestinal macrophage polarization. JTCD attenuated Caco-2 cell barrier injury by regulating macrophage polarization through the Notch signaling pathway. CONCLUSION:These results demonstrate that JTCD improves intestinal barrier damage in sepsis by modulating Notch-mediated macrophage polarization.
Pancreatic ductal adenocarcinoma (PDAC) remains one of the most aggressive malignancies with limited diagnostic and prognostic markers. Neutrophil extracellular traps (NETs) have recently been implicated in cancer progression, but their clinical relevance in PDAC remains underexplored. In this preliminary study, we investigated NET levels in both peripheral blood and tumor tissues from PDAC patients (n = 30) and explored their associations with clinicopathological features. We quantified NETs using a multiparametric approach that included immunohistochemistry, immunofluorescence, qRT-PCR, ELISA, and flow cytometry. Plasma NET-associated DNA was measured using the Quant-iT PicoGreen assay. Receiver operating characteristic (ROC) analysis was performed to assess the diagnostic potential of NETs. We found NET levels were significantly elevated in both tumor tissue and the circulation of PDAC patients compared with healthy controls. The levels of NETs were strikingly higher in patients with advanced tumor stages and grades. Patients' NETs showed a typical morphology with enlarged nuclei, thread-like DNA fibres, and MPO-positive granules, which was confirmed by immunofluorescence analysis. The ROC analysis demonstrated that NETs displayed promising diagnostic performance (AUC = 0.852) compared to widely used conventional markers CEA and CA19-9 within the study cohort. In conclusion, our findings provide preliminary evidence that increased NETosis is associated with PDAC progression and highlight its potential as a diagnostic biomarker. Larger, independent studies are needed to validate these observations and to determine the clinical relevance of NET-associated markers in PDAC.
Rheumatoid arthritis (RA) is a chronic autoimmune disease characterized by persistent articular inflammation, cartilage destruction and aberrant synovial angiogenesis. While current cytokine-centric therapies have revolutionized RA management, their limitations highlight the need for a deeper understanding of the integrated synovial microenvironment. This review explores the critical role of exosomes as central regulatory nodes orchestrating intercellular communication within the RA joint. Under conditions of hypoxia and metabolic stress, exosomes secreted by fibroblast-like synoviocytes (FLS) and immune cells are dynamically loaded with pathogenic cargo, including microRNAs and autoantigens. These vesicles actively modulate macrophage phenotypes, moving beyond the traditional binary framework to reflect a continuum of pro-inflammatory activation, reprogram T-cells to favour pathogenic Th17 expansion while impairing regulatory T-cells (Tregs), and amplify autoreactive B-cell activation for sustained autoantibody production. While exosomes sustain the hypoxia-inflammation-angiogenesis axis and promote invasive pannus formation independently of transient soluble cytokines, we critically delineate which of these mechanisms are validated in RA-specific models against broader immunobiology. We propose that targeting these exosome-mediated signalling cascades offers a promising strategy to overcome therapeutic resistance, signifying their potential as novel therapeutic interventions and high-fidelity diagnostic biomarkers. Further, the significant translational, delivery, and standardization challenges are also addressed.
The neonatal Fc receptor (FcRn) recycles immunoglobulin G (IgG) in cells and is responsible for the long half-life of IgG relative to other plasma proteins. FcRn also recycles pathogenic IgG autoantibodies and is the target for several new targeted therapeutic agents in IgG autoantibody-driven disorders. These therapeutics include rozanolixizumab, a high-affinity monoclonal antibody that directly blocks the IgG binding site on FcRn in a pH-independent manner. This study explored the impact of these molecular characteristics on rozanolixizumab's cellular uptake, endosomal trafficking and recycling. Another anti-FcRn therapeutic, the Fc fragment MST-HN IgG Fc (an analog of efgartigimod), a competitive antagonist with weaker affinity and pH-dependent binding to FcRn, was included for comparison. Using high-content imaging methods in human umbilical vein endothelial cells (HUVECs), a time- and concentration-dependent uptake of fluorescently labeled rozanolixizumab into intracellular compartments was observed. Uptake was rapid, pH-independent, and competed out with unlabeled inhibitor, supporting a receptor-mediated mechanism. Conversely, uptake of MST-HN IgG Fc was slower and required higher concentrations to detect uptake, which was pH-dependent, not competed out with unlabeled inhibitor, and occurred with similar potency in cells that did not express FcRn, suggesting a receptor-independent mechanism such as fluid phase pinocytosis. Using Rab proteins associated with different endosomal compartments, FcRn inhibitors appeared to traffic through recycling compartments in a similar manner in HUVECs, and their return to the cell surface in FcRn-transfected cells occurred with similar kinetics. These data demonstrate the impact of different structural features of FcRn inhibitors on functional outcomes on cells in vitro.
Symptoms of acute SARS-CoV-2 infection often resolve quickly but are sometimes associated with persistent immune dysfunction. The factors that predispose individuals to compromised immune function have not been well defined. We investigated CD4+ T cell phenotype and function in a small cohort of individuals who recovered from mild to moderate SARS-CoV-2 infection without hospitalization and were divided into short or prolonged symptom duration groups. Five individuals with prolonged symptom duration showed marked downregulation of CD4 on CD3+CD8- T cells (CD4low group) and a poor response to TCR stimulation with the superantigen Staphylococcal enterotoxin B (SEB), as shown by weak upregulation of the activation markers CD134, CD25, CD279, and CD69. CD4 surface intensities recovered to normal levels in four of these individuals within 3-12 months. Selected cytokines (IL-1RA, IL-7, and VEGF) were elevated in individuals with low CD4, but plasma levels of anti-S1 IgG did not correlate with CD4 hyporesponsiveness. Bulk RNA sequencing of unstimulated and SEB-treated CD3+CD8- T cells revealed a > 50% reduction in the number of differentially expressed genes in the CD4low group compared to the same individuals after CD4 levels were recovered and a healthy control group. Analyses of differentially expressed genes in unstimulated CD4low cells suggested a response to IFN, while SEB-stimulated CD4low cells showed reduced functionality of T cell activation, differentiation, and glycolysis pathways. In summary, in some individuals, prolonged symptomatic recovery from SARS-CoV-2 infection was associated with evidence of IFN signaling and transient reduction in CD4 expression accompanied by attenuated TCR activation by SEB.
Rheumatoid arthritis (RA) is a joint disease characterized by abnormal development of fibroblast-like synoviocytes (FLSs). Circular RNAs (circRNAs) possess momentous regulatory functions in human disease progression. This research was conducted to investigate regulatory mechanism of circ_0003692 in RA. In this research, circ_0003692 and Toll-like receptor 4 (TLR4) expressions were elevated in RA tissues and RA-fibroblast-like synoviocytes (RA-FLSs) (P < 0.05), but microRNA-1197 (miR-1197) level was decreased (P < 0.01). Functionally, circ_0003692 knockdown restrained RA-FLSs proliferation, inflammation, migration and invasion (P < 0.01). Mechanistically, miR-1197 was identified as a target for circ_0003692 and miR-1197 targeted TLR4. The expressions of circ_0003692 and TLR4 were positively correlated in RA, while miR-1197 and TLR4 expressions were negatively correlated in RA (P < 0.001). Rescue assay further authenticated that interference with circ_0003692 reduced RA-FLSs proliferation and inflammation through miR-1197/TLR4/nuclear factor-transcription factor B (NF-κB) (P < 0.05). In vivo research also vindicated that circ_0003692 knockdown alleviated CIA mice by reducing synovial tissue proliferation and inflammatory cell infiltration, relieving cartilage injury and reducing osteoclast formation in CIA mice (P < 0.05). In summary, interference with circ_0003692 reduced RA-FLSs proliferation and inflammation via miR-1197/TLR4/NF-κB.
OBJECTIVES:Coronary artery disease (CAD) is a chronic inflammatory disorder characterized by immune dysregulation and a higher risk of viral infections. Among the immune cells involved, mucosal-associated invariant T (MAIT) cells participate in antimicrobial defense and tissue repair, yet their contribution to CAD has not been clearly defined. METHODS:Peripheral blood mononuclear cells and plasma were obtained from patients with CAD and from healthy controls. MAIT cell subsets, conventional T cells, and the SARS-CoV-2 receptors ACE2 and CD147 were analyzed by flow cytometry. Cytokines were quantified using ELISA. Additional in-vitro assays were performed to test whether recombinant SARS-CoV-2 spike proteins could influence cell apoptosis or proliferation. RESULTS:The number of circulating MAIT cells was markedly reduced in CAD, most notably within the CD8+ population. In contrast, CD4+ MAIT cells were relatively increased but expressed less CCR5 intensities, suggesting limited migratory ability. Plasma IL-7 concentrations were lower in CAD, while IL-18 and IFN-α2 were higher. These findings indicate a disturbed cytokine environment, especially for MAIT cell activation. CAD samples also showed more CD4+PD-1+ and fewer CD8+CD69+ T cells, pointing toward an exhausted phenotype. IL-18 levels correlated negatively with left-ventricular ejection fraction. Expression of ACE2 and CD147 was similar between groups, and spike-protein exposure did not trigger significant apoptosis or proliferation in vitro. CONCLUSION:CAD is associated with loss and functional alteration of MAIT cells, cytokine imbalance, and T-cell exhaustion. Together, these immune changes may weaken antiviral defense mechanisms in the context of viral infections, such as the SARS-CoV-2 infection.
Background Sepsis-induced myocardial injury (SIMI) has become an important cause of death in septic patients, and it is a multi-faceted pathophysiological process. The present study aims to understand how insulin-like growth factor 2 mRNA-binding protein 2 (IGF2BP2) regulates cardiomyocyte cuproptosis through an m6A-dependent regulation of mitogen-activated protein kinase kinase 1 (MAP2K1), and advance our knowledge of SIMI. Methods In vivo and in vitro SIMI models were developed through lipopolysaccharide (LPS) administration in mice and AC16 cardiomyocytes, respectively. The functions of IGF2BP2 and MAP2K1 in regulating cuproptosis under septic myocardial injury were explored through loss- and gain-of-function approaches. Furthermore, RNA immunoprecipitation (RIP) and methylated RNA immunoprecipitation (MeRIP) experiments as well as actinomycin D experiments confirmed the regulatory interaction of IGF2BP2 with MAP2K1. Results In SIMI models, the IGF2BP2 mRNA and protein expressions were all significantly upregulated, accompanied by myocardial pathological damage and poor cardiac function. Knockdown of IGF2BP2 considerably lessened LPS-induced myocardial injury, lowered copper levels in serum and myocardial tissue, and rectified the changed expression of key cuproptosis-related proteins such as MAP2K1, solute carrier family 31 member 1 (SLC31A1), ferredoxin 1 (FDX1), heat shock protein 70 (HSP70), dihydrolipoamide S-acetyltransferase (DLAT), and lipoyl synthase (LIAS). Mechanistically, IGF2BP2 interacts with MAP2K1 mRNA to improve the mRNA stability and protein expression of MAP2K1 through N6-Methyladenosine (m6A) modification. In addition, overexpression of MAP2K1 abrogated the suppressive effects of IGF2BP2 knockdown on cardiomyocyte cuproptosis. Conclusion IGF2BP2 improves MAP2K1 expression stability via m6A modification, which promotes cardiomyocyte cuproptosis and worsens SIMI. This mechanism might give some possible therapy targets for curing septic myocardium injury.
Glioblastoma (GBM) and other malignant gliomas are associated with aggressive progression, high recurrence rates, and poor long-term outcomes, while current standard therapies provide limited survival benefit. Neoantigen-based immunotherapy offers tumor specificity but is severely restricted in gliomas by HLA-Ia downregulation, pronounced intratumoral heterogeneity, an immunosuppressive tumor microenvironment, and the blood-brain barrier (BBB). In this review, we summarize recent advances and propose a multidimensional framework to address these barriers. Specifically, we discuss the potential use of HLA-E as an alternative antigen-presentation platform, γδ T cells as complementary effector populations capable of partially bypassing classical HLA-Ia dependence, artificial intelligence-assisted neoantigen prioritization and optimization, and emerging BBB-penetrating delivery technologies. Together, these strategies uncouple neoantigen targeting from individual HLA restrictions, establishing a "genotype-agnostic" foundation. Ultimately, this integrated framework aims to develop broadly applicable, off-the-shelf neoantigen immunotherapies, improving translational feasibility and providing new directions for overcoming immune escape in gliomas.
Purpose Preeclampsia (PE) is a multifactorial disease, in which immune dysregulations especially pathogenic autoantibody AT1-AA is critically involved. MFG-E8 deficiency can lead to autoimmune disorders, yet its role in AT1-AA-mediated PE remains unclear. Thus, this study explores whether MFG-8 inhibits AT1-AA production by promoting macrophage phagocytosis of apoptosis trophoblasts. Methods Placental MFG-E8 expression, trophoblast apoptosis, and serum levels of TNF-α, sFlt-1, and AT1-AA were detected between PE patients and healthy subjects. The LPS-induced PE rat models and trophoblast-macrophage co-culture system were established to evaluate the effects of MFG-E8 on AT1-AA production and macrophage phagocytic function. Results Reduced placental MFG-E, increased trophoblast apoptosis, and elevated serum levels of TNF-α, sFlt-1, and AT1-AA were detected in PE patients. MFG-E8 administration attenuated PE symptoms in rats, reduced AT1-AA expressions, and promoted macrophage clearance of apoptotic trophoblasts and AT1R antigen in vitro. Conclusion MFG-E8 alleviates PE progression by promoting macrophage phagocytosis of apoptotic trophoblasts and inhibiting AT1-AA production.
OBJECTIVE:To explore the impact of ultraviolet B (UVB) on the DNA methylation and activation in CD4+ T cells of systemic lupus erythematosus (SLE) patients and the underlying mechanisms. METHODS:CD4+ T cells were isolated and separated from both healthy controls (HCs) and SLE patients, then exposed to 100 mJ/cm2 UVB. CD4+ T cell activation and DNA methylation levels were assessed by RT-qPCR and ELISA. PBMC sequencing data and CD4+ T cell expression data from the GEO platform were used to analyze the expression of GADD45A. RT-qPCR was utilized to measure the levels of miR-410, GADD45A, and CD70 before and after UVB exposure. GADD45A protein expression levels were detected by Western blot. Dual-luciferase reporter gene assay was used to analyze the relationship between miR-410 and GADD45A. SLE CD4+ T cells were transfected with miR-410 mimics, and GADD45A, DNA methylation, and cell activation levels were measured after UVB irradiation. RESULTS:At baseline, SLE patients showed significantly higher levels of DNA hypomethylation and activation in CD4+ T cells compared to HCs, these effects were further enhanced after exposure to UVB. MiR-410 was downregulated in SLE CD4+ T cells, while GADD45A showed high expression levels. Dual luciferase reporter gene experiments showed that miR-410 directly downregulates GADD45A. Overexpression of miR-410 can consequently downregulate the expression levels of GADD45A, improve the DNA hypomethylation and cell activation induced by UVB. CONCLUSION:These results suggest that miR-410 targets and negatively regulates GADD45A, thereby involving in UVB-induced cell activation and DNA hypomethylation in SLE CD4+ T cells.
Microglia are resident immune cells in the central nervous system mediating brain inflammatory responses. The flavonoid silibinin has been found to restrict the neuronal inflammatory conditions in vivo. To fully reveal the underlying mechanisms, effects of silibinin on neuroinflammation was evaluated in lipopolysaccharides (LPS)-stimulated murine microglia BV2. The increased NO level, and the up-regulated pro-inflammatory proteins including iNOS and COX-2 in LPS-treated cells were all restricted by the treatment with silibinin. Further investigation showed that, mitochondrial disorders caused by LPS, including the excessive fission, loss of mitochondrial membrane potentials and intracellular ATP levels, augmented ROS and oxidative damages of mitochondrial DNA (mtDNA), were all attenuated by the treatment with silibinin. The protective effect of silibinin against the STING and NLRP3 inflammasome pathways is attributed to its ability to restore mitochondrial quality control. Of note, triggering receptors expressed on myeloid cells 2 (TREM2), a transmembrane receptor important for modulating microglia-associated inflammation, was low in LPS-treated cells but largely preserved in cells co-treated with silibinin. Molecular docking results show that silibinin has a binding potential with TREM2, which has also been confirmed in CETSA assay. TREM2 knockdown in microglia promotes a proinflammatory phenotype and mitochondrial damage which was reversed with silibinin treatment by increasing the stability of TREM2. Our data show that silibinin reduces mitochondrial damage and proinflammatory activation in microglia through the stabilization of TREM2. These results highlight the potential of silibinin as a treatment in neuroinflammatory diseases.
Background Rheumatoid arthritis (RA) is a chronic autoimmune disease characterized by persistent synovial inflammation, progressive joint destruction, and long-term disability. Interleukin-1β (IL-1β) is a key pro-inflammatory cytokine implicated in RA pathogenesis. Wnt1-inducible signaling pathway protein 3 (WISP-3) has been associated with joint homeostasis and RA development, but the molecular mechanisms by which WISP-3 regulates synovial inflammation remain poorly understood. Methods In this in vitro study, human RA synovial fibroblasts (RASFs) were treated with increasing concentrations of WISP-3 to evaluate IL-1β expression at both mRNA and protein levels. The involvement of focal adhesion kinase (FAK), c-Jun N-terminal kinase (JNK), and c-Jun signaling was investigated using pharmacological inhibitors and siRNA-mediated gene silencing. Protein phosphorylation and transcriptional activity were assessed to delineate the signaling cascade. Results WISP-3 significantly upregulated IL-1β expression in a dose-dependent manner. Mechanistic analyses demonstrated that WISP-3 activated FAK, which in turn induced phosphorylation of JNK and c-Jun. This signaling cascade enhanced transcriptional activity and promoted IL-1β production. Blockade of FAK, JNK, or c-Jun, either by selective inhibitors or siRNA-markedly attenuated WISP-3-induced IL-1β expression, confirming that the FAK/JNK/c-Jun axis plays a major role in WISP-3-induced IL-1β expression. Conclusion These in vitro findings indicate that WISP-3 acts as a pro-inflammatory mediator in RA by promoting IL-1β expression primarily through activation of the FAK/JNK/c-Jun pathway, with additional contributions from other signaling pathways.
