TGFB1 and rheumatoid arthritis: Moreover, 4-IPP has shown good therapeutic effects in rheumatoid arthritis through its capacity of attenuation of the MAPK/COX2/PGE2 signaling cascade [11] and 4-IPP treatment significantly decreases the expression of TGF-β1 in joint capsule fibroblasts that attenuates joint capsule inflammatory cell infiltration [52, 53], which indicating the important role of 4-IPP in inflammation diseases.