ASIC1a-RNAi and PCTX-1 have been reported to decrease the extracellular acidification-induced invasion and migration of RA-FLSs and the expression of MMP2, MMP9, and p-FAK, which are upregulated by ASIC1a (19), suggesting that these proteins may be downstream signaling molecules of ASIC1a that are involved in synovial migration and invasion. This evidence concerns the gene MMP2 and rheumatoid arthritis.