Expression analysis of platelet-derived growth factor receptor alpha and its ligands in the developing mouse lung

Activation of the platelet-derived growth factor receptor-a (PDGFRa) signaling pathway is critically important during lung alveogenesis, the process in lung development during which alveoli are formed from the terminal alveolar sacs. Several studies have aimed to characterize the expression patterns of PDGFRa and its two ligands (PDGF-A and -C) in the lung, but published analyses have been limited to embryonic and/or perinatal time points, and no attempts have been made to characterize both receptor and ligand expression simultaneously. In this study, we present a detailed map of the expression patterns of PDGFRa, PDGF-A and PDGF-C during the entire period of lung development, that is, from early embryogenesis until adulthood. Three different reporter mice were analyzed (Pdgfa ex4-COIN-INV-lacZ, Pdgfc tm1Nagy, and Pdgfra tm11(EGFP) Sor), in which either lacZ or H2B-GFP were expressed under the respective promoter in gene-targeted alleles. A spatiotemporal dynamic expression was identified for both ligands and receptor. PDGF-A and PDGF-C were located to distinct populations of epithelial and smooth muscle cells, whereas PDGFRa expression was located to different mesenchymal cell populations. The detailed characterization of gene expression provides a comprehensive map of PDGFRa signaling in lung cells, opening up for a better understanding of the role of PDGF signaling during lung development.