MAPK3 and idiopathic pulmonary fibrosis: To address this, we treated IPF patient-derived fibroblasts with or without 10μM U0126 (1,4-diamino-2,3-dicyano-1,4-bis (2-aminophenylthio) butadiene), an inhibitor of ERK1/2 activation, after which the fibroblasts were treated with 1mM SS or control (Figure 5C).