In this study, NR1D1 expression was increased in synovial tissues from patients with RA compared to those with OA, and pharmacological activation of NR1D1 by SR9009 or overexpression of NR1D1 decreased the expression of proinflammatory cytokines and MMPs in RA FLSs. This evidence concerns the gene NR1D1 and rheumatoid arthritis.