Novel insight into the role of α-actinin-1 in rheumatoid arthritis.

The knowledge of rheumatoid arthritis (RA) pathology is rapidly advancing and becoming more and more complex, and a simple fact is that the major organ targeted by RA pathogenic factors is the synovium. It is well known that fibroblast-like synovial (FLS) cell is the major cell-type for constructing synovium. Following stimulation by pro-inflammatory cytokines, FLS cells are phenotypically changed to have the capability to proliferate abnormally. Recently we demonstrated that α-actinin-1 (ACTN1) gene is significantly increased in synovial tissues obtained from RA, as compared to osteoarthritis (OA). We therefore reviewed the literature about α-actinins (ACTNs) and we now propose that ACTN1 may function as a "terminal effector" of intracellular signalings initiated by tumor necrosis factor-α (TNF-α) and interleukin-1 (IL-1) in RA. Future research on ACTN1 may help to improve the current therapeutic and diagnostic strategies of RA.