ACTA1 and idiopathic pulmonary fibrosis: In the GSE17978 database(https://www.ncbi.nlm.nih.gov/geo/), we found that the mRNA expression of GPR91 in IPF fibroblasts was higher than that of the normal control, and the expression of GPR91 was positively correlated with α-SMA, FN and COL1 expressions (Supplemental Fig. 3A,B).