ACTA1 and Hepatic fibrosis: However, GW570 nonthiozolidinedione PPAR agonist inhibited collagen I α1 and α-SMA mRNA and protein expression on isolated stellate cells in in vivo model of hepatic fibrosis because physical interaction between PPAR-γ and JunD in stellate cells suppresses AP-1 activity, which prevents their activation [97].