In addition, we demonstrate that treatment of primary IPF fibroblasts with a TG2-selective inhibitor 1–155 and a cell impermeable TG2 inhibitor R281 reverses the myofibroblast phenotype with reduced expression of FN, TG2 and αSMA and reduced deposition into the ECM of TG2, FN and TGFβ1. Here, TGFB1 is linked to idiopathic pulmonary fibrosis.