SMAD3 and rheumatoid arthritis: Confirming the inhibitory role of Smad7 in tissue fibrosis and inflammation, the Smad7 deficiency observed in RA patients led to enhanced NF-κB activity, Th1/Th17 cell differentiation, and exacerbation of synovial inflammation, probably through the hyperactivation of the TGF-β/Smad3–IL-6 molecular pathway [36].