Rheumatoid arthritis (RA) is a chronic autoimmune disease that affects not only joints but also multiple organ systems including cardiovascular system. Endothelial dysfunction plays an important role in cardiovascular diseases (CVD). In RA, endothelial dysfunction exists at both the macrovascular and the microvascular levels, which is a precursor to vasculitis. This study aimed to investigate the pathogenesis of vasculitis and the therapeutic effect of CP‐25 on vasculitis in high‐fat diet (HFD) collagen‐induced arthritis (CIA) rats. Experimental groups were divided into normal group, HFD group, CIA group, HFD CIA group, CP‐25 group and MTX group. In vitro, IL‐17A was used to stimulate human umbilical vein endothelial cells (HUVECs), and then CP‐25 was used to intervene. Results showed that CP‐25 reduced global scoring (GS), arthritis index (AI), and swollen joint count (SJC) scores, improved histopathological score, reduced T cells percentage, and decreased IL‐17A and ICAM‐1 levels. Besides, CP‐25 reduced the expression of p‐STAT3 to normal levels in vascular of HFD CIA rats. In vitro, IL‐17A promoted the expression of p‐JAK1, p‐JAK2, p‐JAK3, pSTAT3, and ICAM‐1, and CP‐25 inhibited the expression of p‐JAK1, p‐JAK2, p‐JAK3, p‐STAT3, and ICAM‐1. In conclusion, CP‐25 might inhibit endothelial cell activation through inhibiting IL‐17A/JAK/STAT3 signaling pathway, which improves vasculitis in HFD CIA rats.

Objective: To explore the role of B cells in rheumatoid arthritis (RA) and the potential effects and mechanisms of etanercept on B cells. Methods: In RA patients, the levels of tumor necrosis factor-a (TNF-a) and B cell activating factor (BAFF) were detected by ELISA. The percentage of B cell subsets was measured by flow cytometry. Laboratory indicators (rheumatoid factor, C-reactive protein, erythrocyte sedimentation rate) and clinical indicators (disease activity score in 28 joints, health assessment questionnaire score, swollen joint counts, tender joint counts) were measured. The correlation between B cell subsets and laboratory indicators or clinical indicators was analyzed. In mice, B cells proliferation was detected by CCK-8 kit. The expression of TNFRII and the percentage of B cell subsets in spleen were detected by flow cytometry. The expressions of TRAF2, p38, P-p38, p65, P-p65 in B cells were detected by WB. Results: The percentage of CD19 − CD27 + CD138 + plasma B cells was positively correlated with ESR or RF. Etanercept could decrease the percentage of CD19 + total B cells, CD19 + CD27 + memory B cells and CD19 − CD27 + CD138 + plasma B cells, reduce the levels of TNF-a, BAFF, relieve clinical and laboratory indicators in RA patients. In addition, etanercept could inhibit the proliferation of B cells, bate the differentiation of transitional B cells to mature B cells, down-regulate the expression of TNFRII, TRAF2, P-p38, P-p65 in B cells. Conclusion: B cells act a key role in the pathogenesis of RA. Etanercept inhibits B cells differentiation by down-regulating TNFRII/TRAF2/NF-kB signaling pathway.