SMAD7 and pulmonary fibrosis: Thus, although the precise mechanisms remain to be explored, past studies and our findings imply that the inhibitory effect of CB2R activation with YX-2102 on TGF-β-induced EMT and pulmonary fibrosis might be partly ascribed to Nrf2-mediated smad7 elevation that serve to perturb the TGF-beta pathway during this process.