Expression of AIM2 in rheumatoid arthritis and its role on fibroblast-like synoviocyte

Abstract Background To determine whether any differences of AIM2 inflammasome expression levels between rheumatoid arthritis (RA) and osteoarthritis (OA) and investigate the effects of AIM2 when transferred into RA fibroblast-like synoviocytes (RA-FLS).Methods Serum AIM2 levels between OA and RA patients were compared by ELISA. Different expression levels of AIM2, ASC, Caspase-1 and IL-1β between RA and OA synovium were semi-quantified by RT-qPCR and immunohistochemical (IHC) staining. IHC staining were recorded by H scores, and determine the correlation with ESR and CRP levels of RA patients. SiRNA AIM2 was transferred to RA-FLS and observe its effects on proliferation and migration by MTT assay and transwell test respectively.Results In RA sera, no significant difference was observed between OA and RA patients. However, in affected knee synovium, AIM2, ASC, Caspase-1 and IL-1β were expressed higher in RA than that of OA. Plus, H score of AIM2, ASC, and IL-1β were positively correlated to ESR and CRP levels in RA patients. After transferred AIM2 siRNA to FLS and incubation for 48 hours, the proliferation of FLS were significantly inhibited, and the apoptosis rate were significantly increased compared to FLS in control group. However, no effect on migration was detected.Conclusions AIM2 participated in the proliferation of FLS, and might be a potential target for therapy.