Glucocorticoid Regulates Mesenchymal Cell Differentiation Required for Perinatal Lung Morphogenesis and Function

We integrated genome-wide gene expression profiling, ATAC-seq, and single cell RNA-seq data in mice in which GR was deleted or activated to identify the cellular and molecular mechanisms by which glucocorticoids control prenatal lung maturation. GR activated differentiation of a newly defined proliferative mesenchymal progenitor cell (PMP) into matrix fibroblasts (MFB), in part by directly activating extracellular matrix-associated target genes, including Fn1, Col16a4, and Eln and modulating FGF, VEGF, JAK-STAT and WNT signaling. Loss of mesenchymal GR signaling blocked PMP differentiation into mature MFB, which in turn caused proliferation of SOX9+ alveolar epithelial progenitor cells and inhibited differentiation of more mature AT2 and AT1 cells. GR signaling controls genes required for differentiation of a subset of proliferative mesenchymal progenitors into matrix fibroblasts in turn, regulating signals controlling AT2/AT1 progenitor cell proliferation and differentiation, identifying cells and processes by which glucocorticoid signaling regulates fetal lung function. Using system biology approch we integrated genome-wide gene expression profiling, ATAC-seq and single cell RNA-seq data in mice in which GR was deleted or activated to identify the cellular and molecular mechanisms by which glucocorticoids control prenatal lung maturation.