We found that, among the detected ATP ionotropic receptors, P2rx4 was the most highly expressed in nearly all populations of collagen-producing cells as measured by scRNAseq or qPCR (Figures 3A–C); notably, the scRNAseq data indicated that P2rx4 was increased with bleomycin injury and in IPF lung samples relative to control. Here, P2RX4 is linked to idiopathic pulmonary fibrosis.