Paradoxically, αSMA mRNA was decreased in hLFs grown on old ECM implying that other non-ECM signals are required for myofibroblast differentiation, although ECM from human IPF lungs can induce a profibrotic transcriptome in fibroblasts from non-fibrotic lungs[24]. Here, ACTA1 is linked to idiopathic pulmonary fibrosis.