Project description:ObjectivesInflammation and angiogenesis are a significant element of pathogenesis in rheumatoid arthritis (RA). The FLT-1- triggering factor for production of proinflammatory cytokines-might contributes to inflammation in patients with RA. Association of the FLT-1 polymorphisms with different "angiogenic diseases" suggests that it may be a novel genetic risk factor also for RA. The aim of the study was to identify FLT-1 genetic variants and their possible association with sFLT-1 levels, susceptibility to and severity of RA.MethodsThe FLT-1 gene polymorphisms were genotyped for 471 RA patients and 684 healthy individuals. Correlation analysis was performed with clinical parameters, cardiovascular disease (CVD) and anti-citrullinated peptide/protein antibody (ACPA) presence. The sFLT-1 serum levels were evaluated.ResultsThe FLT-1 gene polymorphisms showed no significant differences in the proportion of cases and controls. Furthermore, the FLT-1 rs2296188 T/C polymorphism was associated with ACPA-positive RA. Overall, rs9943922 T/C and rs2296283 G/A are in almost completed linkage disequilibrium (LD) with D' = 0.97 and r2 = 0.83. The FLT-1 rs7324510 A allele has shown association with VAS score (p = 0.035), DAS-28 score (p = 0.013) and ExRA presence (p = 0.027). Moreover, other clinical parameters were also higher in RA patients with this allele. In addition, FLT-1 genetic variants conferred higher sFLT-1 levels in RA patients compared to controls.ConclusionFLT-1 rs7324510 C/A variant may be a new genetic risk factor for severity of RA. Examined factor highly predispose to more severe disease activity as well as higher sFLT-1 levels in RA.
Project description:Rheumatoid arthritis (RA) is an autoimmune rheumatic disease, which do not respond well to current treatment partially. Therefore, further in-depth elucidation of the molecular mechanism and pathogenesis of RA is urgently needed for the diagnosis, personalized therapy and drug development. Herein, we collected 111 RA samples from Gene Expression Omnibus (GEO) database, and conducted differentially expressed genes and GESA analysis. Abnormal activation and imbalance of immune cells in RA were observed. WGCNA was utilized to explore the gene modules and CD8+ T cell-related genes (CRGs) were chosen for KEGG and GO analysis. Besides, to explore biomarkers of RA in depth, machine learning algorithms and bioinformatics analysis were used, and we identified GDF15, IGLC1, and IGHM as diagnostic markers of RA, which was confirmed by clinical samples. Next, ssGSEA algorithms were adopted to investigate the differences in immune infiltration of 23 immune cell subsets between RA and healthy control group. Finally, optimal classification analysis based on consensus clustering combined with ssGSEA algorithms were conducted. GDF15 was revealed that to be positively correlated with mast cells and type 2 T helper cells, but negatively correlated with most other immune cells. On the other hand, IGHM and IGLC1 were negatively correlated with CD56dim natural killer cells, while positively associated with other immune cells. Finally, RA samples in subtype A exhibited a higher immune infiltration status. This study could provide guidance for individualized treatment of RA patients and provide new targets for drug design.
Project description:BackgroundWe recently reported that myeloid sirtuin 6 (Sirt6) is a critical determinant of phenotypic switching and the migratory responses of macrophages. Given the prominent role of macrophages in the pathogenesis of rheumatoid arthritis (RA), we tested whether myeloid Sirt6 deficiency affects the development and exacerbation of RA.MethodsArthritis was induced in wild type and myeloid Sirt6 knockout (mS6KO) mice using collagen-induced and K/BxN serum transfer models. Sirt6 expression (or activity) and inflammatory activities were compared in peripheral blood mononuclear cells (PBMCs) and monocytes/macrophages obtained from patients with RA or osteoarthritis.FindingsBased on clinical score, ankle thickness, pathology, and radiology, arthritis was more severe in mS6KO mice relative to wild type, with a greater accumulation of macrophages in the synovium. Consistent with these findings, myeloid Sirt6 deficiency increased the migration potential of macrophages toward synoviocyte-derived chemoattractants. Mechanistically, Sirt6 deficiency in macrophages caused an inflammation with increases in acetylation and protein stability of forkhead box protein O1. Conversely, ectopic overexpression of Sirt6 in knockout cells reduced the inflammatory responses. Lastly, PBMCs and monocytes/macrophages from RA patients exhibited lower expression of Sirt6 than those from patients with osteoarthritis, and their Sirt6 activity was inversely correlated with disease severity.InterpretationOur data identify a role of myeloid Sirt6 in clinical and experimental RA and suggest that myeloid Sirt6 may be an intriguing therapeutic target. FUND: Medical Research Center Program and Basic Science Research Program through the National Research Foundation of Korea.
Project description:Epigenetic regulation of inflammatory macrophages governs inflammation initiation and resolution in the pathogenesis of rheumatoid arthritis (RA). Nevertheless, the mechanisms underlying macrophage-mediated arthritis injuries remain largely obscure. Here, we found that increased expression of lysine acetyltransferase 2A (KAT2A) in synovial tissues was closely correlated with inflammatory joint immunopathology in both RA patients and experimental arthritis mice. Administration of MB-3, the KAT2A-specific chemical inhibitor, significantly ameliorated the synovitis and bone destruction in collagen-induced arthritis model. Both pharmacological inhibition and siRNA silencing of KAT2A, not only suppressed innate stimuli-triggered proinflammatory gene (such as Il1b and Nlrp3) transcription but also impaired NLR family pyrin domain containing 3 (NLRP3) inflammasome activation in vivo and in vitro. Mechanistically, KAT2A facilitated macrophage glycolysis reprogramming through suppressing nuclear factor-erythroid 2-related factor 2 (NRF2) activity as well as downstream antioxidant molecules, which supported histone 3 lysine 9 acetylation (H3K9ac) and limited NRF2-mediated transcriptional repression of proinflammatory genes. Our study proves that acetyltransferase KAT2A licenses metabolic and epigenetic reprogramming for NLRP3 inflammasome activation in inflammatory macrophages, thereby targeting KAT2A represents a potential therapeutic approach for patients suffering from RA and relevant inflammatory diseases.
Project description:Dendritic cells (DC) have a key role in the initiation and progression of inflammatory arthritis (IA). In this study, we identified a DC population that derive from monocytes, characterized as CD209/CD14+ DC, expressing classical DC markers (HLADR, CD11c) and the Mo-DC marker (CD209), while also retaining the monocytic marker CD14. This CD209/CD14+ DC population is present in the circulation of Healthy Control (HC), with increased frequency in Rheumatoid Arthritis (RA) and Psoriatic arthritic (PsA) patients. We demonstrate, for the first time, that circulatory IA CD209/CD14+ DC express more cytokines (IL1β/IL6/IL12/TNFα) and display a unique chemokine receptor expression and co-expression profiles compared to HC. We demonstrated that CD209/CD14+ DC are enriched in the inflamed joint where they display a unique inflammatory and maturation phenotype, with increased CD40 and CD80 and co-expression of specific chemokine receptors, displaying unique patterns between PsA and RA. We developed a new protocol of magnetic isolation and expansion for CD209+ DC from blood and identified transcriptional differences involved in endocytosis/antigen presentation between RA and PsA CD209+ DC. In addition, we observed that culture of healthy CD209+ DC with IA synovial fluid (SF), but not Osteoarthritis (OA) SF, was sufficient to induce the development of CD209/CD14+ DC, leading to a poly-mature DC phenotype. In addition, differential effects were observed in terms of chemokine receptor and chemokine expression, with healthy CD209+ DC displaying increased expression/co-expression of CCR6, CCR7, CXCR3, CXCR4 and CXCR5 when cultured with RA SF, while an increase in the chemokines CCR3, CXCL10 and CXCL11 was observed when cultured with PsA SF. This effect may be mediated in part by the observed differential increase in chemokines expressed in RA vs PsA SF. Finally, we observed that the JAK/STAT pathway, but not the NF-κB pathway (driven by TNFα), regulated CD209/CD14+ DC function in terms of activation, inflammatory state, and migratory capacity. In conclusion, we identified a novel CD209/CD14+ DC population, which is active in the circulation of RA and PsA, an effect potentiated once they enter the joint. Furthermore, we demonstrated that JAK/STAT inhibition can be used as a therapeutic strategy to decrease the inflammatory state of the pathogenic CD209/CD14+ DC.
Project description:Hyperplasia and migration of fibroblast-like synoviocytes (FLSs) are the key drivers in the pathogenesis of rheumatoid arthritis (RA) and joint destruction. Abundant Yes-associated protein (YAP), which is a powerful transcription co-activator for proliferative genes, was observed in the nucleus of inflammatory FLSs with unknown upstream mechanisms. Using Gene Expression Omnibus database analysis, it was found that Salvador homolog-1 (SAV1), the pivotal negative regulator of the Hippo-YAP pathway, was slightly downregulated in RA synovium. However, SAV1 protein expression is extremely reduced. Subsequently, it was revealed that SAV1 is phosphorylated, ubiquitinated, and degraded by interacting with an important serine-threonine kinase, G protein-coupled receptor (GPCR) kinase 2 (GRK2), which was predominately upregulated by GPCR activation induced by ligands such as prostaglandin E2 (PGE2) in RA. This process further contributes to the decreased phosphorylation, nuclear translocation, and transcriptional potency of YAP, and leads to aberrant FLSs proliferation. Genetic depletion of GRK2 or inhibition of GRK2 by paroxetine rescued SAV1 expression and restored YAP phosphorylation and finally inhibited RA FLSs proliferation and migration. Similarly, paroxetine treatment effectively reduced the abnormal proliferation of FLSs in a rat model of collagen-induced arthritis which was accompanied by a significant improvement in clinical manifestations. Collectively, these results elucidate the significance of GRK2 regulation of Hippo-YAP signaling in FLSs proliferation and migration and the potential application of GRK2 inhibition in the treatment of FLSs-driven joint destruction in RA.
Project description:The polarization of macrophages plays a critical role in the physiological and pathological progression of rheumatoid arthritis (RA). Activated M1 macrophages overexpress folate receptors in arthritic joints. Hence, we developed folic acid (FA)-modified liposomes (FA-Lips) to encapsulate triptolide (TP) (FA-Lips/TP) for the targeted therapy of RA. FA-Lips exhibited significantly higher internalization efficiency in lipopolysaccharide (LPS)-stimulated RAW 264.7 cells than liposomes (Lips) in the absence of folate. Next, an adjuvant-induced arthritis (AIA) rat model was established to explore the biodistribution profiles of FA-Lips which showed markedly selective accumulation in inflammatory paws. Moreover, FA-Lips/TP exhibited greatly improved therapeutic efficacy and low toxicity in AIA rats by targeting M1 macrophages and repolarizing macrophages from M1 to M2 subtypes. Overall, a safe FA-modified liposomal delivery system encapsulating TP was shown to achieve inflammation-targeted therapy against RA via macrophage repolarization.
Project description:Rheumatoid arthritis (RA) is a chronic autoimmune inflammatory arthropathy associated with articular damage and attendant comorbidities. Even although RA treatment has advanced remarkably over the last decade, a significant proportion of patients still do not achieve sustained remission. The cause of RA is not yet known despite the many potential mechanisms proposed. It has been confirmed that RA is associated with dysregulated immune system and persistent inflammation. Therefore, management of inflammation is always the target of therapy. Sinomenine (SIN) is the prescription drug approved by the Chinese government for RA treatment. A previous study found that SIN was a robust anti-inflammation drug. In this study, we screened the different secretory cytokines using inflammation antibody arrays and qRT-PCR in both LPS-induced and SIN-treated RAW264.7 cells followed by evaluation of the ability of SIN to modulate cytokine secretion in a cell model, collagen-induced arthritis (CIA) mouse model, and RA patients. Several clinical indexes affecting the 28-joint disease activity score (DAS28) were determined before and after SIN treatment. Clinical indexes, inflammatory cytokine secretion, and DAS28 were compared among RA patients treated with either SIN or methotrexate (MTX). To explore the mechanism of SIN anti-inflammatory function, RA-associated monocyte/macrophage subsets were determined using flow cytometry in CIA mouse model and RA patients, both treated with SIN. The results demonstrated that SIN regulated IL-6, GM-CSF, IL-12 p40, IL-1?, TNF-?, IL-1?, KC (CXCL1), Eotaxin-2, IL-10, M-CSF, RANTES, and MCP-1 secretion in vivo and in vitro and reduced RA activity and DAS28 in a clinical setting. Furthermore, SIN attenuated CD11b+F4/80+CD64+ resident macrophages in the synovial tissue, CD11b+Ly6C+CD43+ macrophages in the spleen and draining lymph nodes of CIA mice. The percentage of CD14+CD16+ peripheral blood mononuclear cells was reduced by SIN in RA patients. These data indicated that SIN regulates the secretion of multiple inflammatory cytokines and monocyte/macrophage subsets, thereby suppressing RA progression. Therefore, along with MTX, SIN could be an alternative cost-effective anti-inflammatory agent for treating RA.
Project description:Defective apoptotic death of activated macrophages has been implicated in the pathogenesis of rheumatoid arthritis (RA). However, the molecular signatures defining apoptotic resistance of RA macrophages are not fully understood. Here, global transcriptome profiling of RA macrophages revealed that the osmoprotective transcription factor nuclear factor of activated T cells 5 (NFAT5) critically regulates diverse pathologic processes in synovial macrophages including the cell cycle, apoptosis, and proliferation. Transcriptomic analysis of NFAT5-deficient macrophages revealed the molecular networks defining cell survival and proliferation. Proinflammatory M1-polarizing stimuli and hypoxic conditions were responsible for enhanced NFAT5 expression in RA macrophages. An in vitro functional study demonstrated that NFAT5-deficient macrophages were more susceptible to apoptotic death. Specifically, CCL2 secretion in an NFAT5-dependent fashion bestowed apoptotic resistance to RA macrophages in vitro. Injection of recombinant CCL2 into one of the affected joints of Nfat5+/- mice increased joint destruction and macrophage infiltration, demonstrating the essential role of the NFAT5/CCL2 axis in arthritis progression in vivo. Moreover, after intra-articular injection, NFAT5-deficient macrophages were more susceptible to apoptosis and less efficient at promoting joint destruction than were NFAT5-sufficient macrophages. Thus, NFAT5 regulates macrophage survival by inducing CCL2 secretion. Our results provide evidence that NFAT5 expression in macrophages enhances chronic arthritis by conferring apoptotic resistance to activated macrophages.
Project description:Rheumatoid arthritis (RA) is a debilitating autoimmune disease characterized by chronic joint inflammation and cartilage damage. Current therapeutic strategies often result in side effects, necessitating the development of targeted and safer treatment options. This study introduces a novel nanotherapeutic system, 2-APB@DGP-MM, which utilizes macrophage membrane (MM)-encapsulated nanoparticles (NPs) for the targeted delivery of 2-Aminoethyl diphenylborinate (2-APB) to inflamed joints more effectively. The NPs are designed with a matrix metalloproteinase (MMP)-cleavable peptide, allowing for MMP-responsive drug release within RA microenvironment. Comprehensive in vitro and in vivo assays confirmed the successful synthesis and loading of 2-APB into the DSPE-GPLGVRGC-PEG (DGP) NPs, as well as their ability to repolarize macrophages from a pro-inflammatory M1 to an anti-inflammatory M2 phenotype. The NPs demonstrated high biocompatibility, low cytotoxicity, and enhanced cellular uptake. In a collagen-induced arthritis (CIA) mouse model, intra-articular injection of 2-APB@DGP-MM significantly reduced synovial inflammation and cartilage destruction. Histological analysis corroborated these findings, demonstrating marked improvements in joint structure and delayed disease progression. Above all, the 2-APB@DGP-MM nanotherapeutic system offers a promising and safe approach for RA treatment by modulating macrophage polarization and delivering effective agents to inflamed joints.