The Role Of Complement Factor H In The Pathogenesis Of Rheumatoid Arthritis

Purpose:To explore the role of complement factor H(CFH)in rheumatoid arthritis(RA)and provide new insights for the treatment of RA.Methods:Peripheral blood samples from newly diagnosed RA patients,autoimmune disease controls,and healthy controls were collected.The level of serum CFH was determined by ELISA.Monocytes were stimulated with different inflammatory cytokines in vitro to evaluate the interaction between cytokines and CFH.Furthermore,the regulation of tumor necrosis factor-?(TNF-?)induced inflammatory activity by CFH was verified by ELISA and western blotting(WB)in both monocytes and fibroblast-like synoviocytes(FLS).The downstream molecular pathway of CFH was explored by RNA sequencing(RNA-seq),and differential gene analysis was performed using R package "edgeR",and we further verified the upregulation of EIF3C in monocytes and FLS through western blotting.Finally,collagen-induced arthritis(CIA)mouse model was constructed to further verify the protective effect of CFH in arthritis in vivo.Results:The concentration of CFH was significantly increased in the serum of RA patients(577.4 jig/ml vs 460.6 ?g/ml,p<0.001),and the level of CFH was positively correlated with the disease activity.In addition,CFH in synovial fluid tended to be up-regulated compared with the plasma of RA patients.CFH could significantly inhibit the secretion of TNF-?-induced inflammatory factors IL-6(interleukin-6)and IL-1?(interleukin-1?)in monocytes(IL-6:1.03 vs 1.38,p=0.006;IL-1?:1.30 vs 1.77,p=0.002).In addition,CFH combined with TNF-? could significantly reduce the relative expression of cleaved caspase-3(c-Casp-3)and GSDME-N(c-Casp-3:0.398 vs 0.652,p=0.016;GSDME-N:0.744 vs 0.861,p=0.039).And in FLS,CFH significantly inhibited the secretion of TNF-?-induced IL-6 and matrix metallopeptidase 3(MMP3)(IL-6:12h,554.4 pg/ml vs 993.3 pg/ml,p=0.006;24h;1082.0 pg/ml vs 1200.1 pg/ml,p=0.012.MMP3:12h,483.0 pg/ml vs 728.9 pg/ml,p=0.002;24h,1557.1 pg/ml vs 2231.2 pg/ml,p=0.006).Differential gene analysis of RNA-seq profile found that CFH significantly increased the expression of EIF3C in monocytes(p=0.016).Consistently,we verified that CFH could up-regulate the expression of EIF3C in the presence of TNF-? using WB(1.012 vs 0.7985,p=0.023).In addition,in the CIA mouse model,we verified that CFH has a protective effect on the joints and increases the expression of EIF3C.Conclusion:CFH might achieve anti-inflammatory effects through up-regulating EIF3C,thus inhibiting pyroptosis mediated by the TNF-?-induced Casp-3-GSDME pathway.And it shed light on a new direction for the clinical design of new inhibitors to treat RA.