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Rheumatoid arthritis (RA) is a persistent autoimmune disease. Fibroblast-like synoviocytes (FLS) are a key component of invasive pannus and a pathogenetic mechanism in RA. Expression of bone morphogenetic protein 3 (BMP3) mRNA is reportedly decreased in the arthritic synovium. We previously showed that BMP3 expression is significantly downregulated in the synovial tissues of RA patients and models of adjuvant-induced arthritis (AIA). In the present study, we explored the association between BMP3 and FLS migration and secretion of proinflammatory factors in RA. We found that inhibition of BMP3 expression using BMP3 siRNA increased the proinflammatory chemokines and migration of FLS stimulated with TNF-α. Inhibition of BMP3 expression also increased expression of IL-6, IL-1β, IL-17A, CCL-2, CCL-3, VCAM-1, MMP-3, and MMP-9, but not TIMP-1, in AIA and RA FLS. Correspondingly, induction of BMP3 overexpression through intra-articular injection of ad-BMP3 diminished arthritis severity in AIA rats. We also found that BMP3 may inhibit activation of TGF-β1/Smad signaling. These data indicate that BMP3 may suppress the proliferation and migration of FLS via the TGF-β1/Smad signaling pathway.

Rheumatoid arthritis is a chronic systemic autoimmune disease characterized by synovial hyperplasia, inflammatory cell infiltration, and proliferation of inflammatory tissue (angiogranuloma). The destruction of joints and surrounding tissues eventually causes joint deformities and dysfunction or even loss. The S100 protein family is one of the biggest subtribes in the calcium-binding protein family and has more than 20 members. The overexpression of most S100 proteins in rheumatoid arthritis is closely related to its pathogenesis. This paper reviews the relationship between S100 proteins and the occurrence and development of rheumatoid arthritis. It will provide insights into the development of new clinical diagnostic markers and therapeutic targets for rheumatoid arthritis.

Rheumatoid arthritis (RA) is characterized by a tumor-like expansion of the synovium and subsequent destruction of adjacent articular cartilage and bone. In our previous work we showed that phosphatase and tension homolog deleted on chromosome 10 (PTEN) contributes to the activation of fibroblast-like synoviocytes (FLS) in adjuvant-induced arthritis (AIA), but the underlying mechanism is not unknown. In this study, we show that PTEN is downregulated while DNA methyltransferase (DNMT)1 is upregulated in FLS from RA patients and a rat model of AIA. DNA methylation of PTEN was increased by administration of tumor necrosis factor (TNF)-α in FLS of RA patients, as determined by chromatin immunoprecipitation and methylation-specific PCR. Treatment with the methylation inhibitor 5-azacytidine suppressed cytokine and chemokine release and FLS activation in vitro and alleviated paw swelling in vivo. PTEN overexpression reduced inflammation and activation of FLS via protein kinase B (AKT) signaling in RA, and intra-articular injection of PTEN-expressing adenovirus into the knee of AIA rats markedly reduced inflammation and paw swelling. Thus, PTEN methylation promotes the inflammation and activation of FLS in the pathogenesis of RA. These findings provide insight into the molecular basis of articular cartilage destruction in RA, and indicate that therapeutic strategies that prevent PTEN methylation may an effective treatment.

Background: Rheumatoid arthritis (RA) is characterized by a tumor-like expansion of the synovium and the subsequent destruction of adjacent articular cartilage and bone. Recent studies have shown that phosphatase and tension homolog deleted on chromosome 10 (PTEN) might contribute to the survival of fibroblast-like synoviocytes (FLS) and the production of pro-inflammatory cytokines in RA.Methods : The expression was determined in RA and adjuvant-induced arthritis (AIA) synovial tissues by immunohistochemistry. FLSs were treatment with bpv, PTEN-RNAi or over-expression plasmid in RA and AIA. FLSs migration was assessed. The ad-PTEN was also injected into the knee of AIA in vivo. Chromatin Immunoprecipitation (ChIP) and Methylation-special PCR (MSP) assay were used to study the expression of PTEN mRNA in DNA methylation.Results : Down-regulated level of PTEN expression was observed in RA and AIA. Inhibition PTEN expression by bpv or PTEN-RNAi could promote the expression of pro-inflammatory cytokines, chemokines and migration of FLS with TNF-α in RA and AIA. Consistently, over-expression of PTEN reduced their low-expression of pro-inflammatory cytokines, chemokines and migration. Intra-articular injection of ad-PTEN in AIA knees dramatically reduced inflammatory and paw swelling in vivo. The ChIP and MSP assay has clearly detected the DNA methylation of PTEN was increased in FLS with TNF-α. Moreover, intraperitoneally injected 5-Aza in AIA also suppressed the inflammatory and paws swelling in vivo.Conclusions: Our findings suggest that over-expression PTEN attenuates the formation of pro-inflammatory cytokines, chemokines and migration of FLS, and it may be regulated by DNA methylation in the pathogenesis of RA.

Background: Rheumatoid arthritis (RA) is characterized by a tumor-like expansion of the synovium and the subsequent destruction of adjacent articular cartilage and bone. Recent studies have shown that phosphatase and tension homolog deleted on chromosome 10 (PTEN) might contribute to the survival of fibroblast-like synoviocytes (FLS) and the production of pro-inflammatory cytokines in RA. Methods: The expression was determined in RA and adjuvant-induced arthritis (AIA) synovial tissues by immunohistochemistry. FLSs were treatment with bpv, PTEN-RNAi or over-expression plasmid in RA and AIA. FLSs migration was assessed. The ad-PTEN was also injected into the knee of AIA in vivo. Chromatin Immunoprecipitation (ChIP) and Methylation-special PCR (MSP) assay were used to study the expression of PTEN mRNA in DNA methylation. Results: Down-regulated level of PTEN expression was observed in RA and AIA. Inhibition PTEN expression by bpv or PTEN-RNAi could promote the expression of pro-inflammatory cytokines, chemokines and migration of FLS with TNF-α in RA and AIA. Consistently, over-expression of PTEN reduced their low-expression of pro-inflammatory cytokines, chemokines and migration. Intra-articular injection of ad-PTEN in AIA knees dramatically reduced inflammatory and paw swelling in vivo. The ChIP and MSP assay has clearly detected the DNA methylation of PTEN was increased in FLS with TNF-α. Moreover, intraperitoneally injected 5-Aza in AIA also suppressed the inflammatory and paws swelling in vivo. Conclusions: Our findings suggest that over-expression PTEN attenuates the formation of pro-inflammatory cytokines, chemokines and migration of FLS, and it may be regulated by DNA methylation in the pathogenesis of RA. Funding Statement: This study is supported by the National Natural Science Foundation of China (No. 81770609). Declaration of Interests: All authors declare no conflict interests. Ethics Approval Statement: All experimental protocols used on the animals were approved by the institutions’ subcommittees on animal care of Anhui Medical University (approval number: 20160253).

Background/aims Rheumatoid arthritis (RA) is characterized by a tumor-like expansion of the synovium and the subsequent destruction of adjacent articular cartilage and bone. Recent studies have shown that phosphatase and tension homolog deleted on chromosome 10 (PTEN) might contribute to the surviva of fibroblast-like synoviocytes (FLSs) and the production of pro-inflammatory cytokines in RA. The purpose of this study was to explore the functions and underlying mechanisms of PTEN in the proliferation and migration of FLSs. Methods FLSs were obtained from adjuvant-induced arthritis (AIA) and normal rats. The expression levels of PTEN, c-Myc, cyclin D1, PCNA, and MMP-9 were detected by quantitative-real-time-PCR and western blot assay. A BrdU proliferation assay, cell cycle analysis, and a wound-healing assay were used to study the role of PTEN in FLSs treated with PTEN inhibitor bpv, specific small interfering RNA targeting PTEN (PTEN-RNAi) or a PTEN over-expression vector (PTEN-GV141). Chromatin immunoprecipitation and methylation-special PCR assays were used to study the expression of PTEN mRNA in the presence of DNA methylation. Results PTEN expression was downregulated in AIA FLSs in comparison to normal rats. Moreover, inhibition of PTEN expression by bpv or PTEN-RNAi could promote the proliferation and migration of FLSs, and increase the expression of c-Myc, cyclin D1, PCNA, and MMP-9 in AIA FLSs, but had no effect on TIMP-1 expression.In addition, transfection of AIA FLSs with PTEN-GV141 reduced their proliferation and migration. Further study indicated that DNA methylation could regulate PTEN expression in AIA. Conclusion Our findings suggest that PTEN might play a pivotal role in the proliferation and migration of FLSs through the activation of the AKT signaling pathway. Additionally, PTEN expression may be regulated by DNA methylation in the pathogenesis of AIA.