In this study, we found that metformin significantly upregulates BMP2 and PPARg (at the mRNA level), increases the phosphorylation of PPARγ protein at Ser112, upregulates the downstream target PLIN238,39 and induces lipid-droplet accumulation in human IPF lung fibroblasts. Here, BMP2 is linked to idiopathic pulmonary fibrosis.