Transmural pressure signals through retinoic acid to regulate lung branching. Author Jacob Jaslove, Katharine Goodwin, Aswin Sundarakrishnan, James Spurlin, Sheng Mao, Andrej Košmrlj, Celeste Nelson Publication Year 2022 Type Journal Article Abstract During development, the mammalian lung undergoes several rounds of branching, the rate of which is tuned by the relative pressure of the fluid within the lumen of the lung. We carried out bioinformatics analysis of RNA-sequencing of embryonic mouse lungs cultured under physiologic or sub-physiologic transmural pressure and identified transcription factor-binding motifs near genes whose expression changes in response to pressure. Surprisingly, we found retinoic acid (RA) receptor binding sites significantly overrepresented in the promoters and enhancers of pressure-responsive genes. Consistently, increasing transmural pressure activates RA signaling, and pharmacologically inhibiting RA signaling decreases airway epithelial branching and smooth muscle wrapping. We found that pressure activates RA signaling through the mechanosensor Yap. A computational model predicts that mechanical signaling through Yap and RA affects lung branching by altering the balance between epithelial proliferation and smooth muscle wrapping, which we test experimentally. Our results reveal that transmural pressure signals through RA to balance the relative rates of epithelial growth and smooth muscle differentiation in the developing mouse lung and identify RA as a previously unreported component in the mechanotransduction machinery of embryonic tissues. Keywords Animals, Morphogenesis, Mice, Signal Transduction, Computer Simulation, Stress, Mechanical, Cells, Cultured, Epithelial Cells, Lung, Receptors, Retinoic Acid, Myocytes, Smooth Muscle, Tretinoin Journal Development Volume 149 Issue 2 Date Published 2022 Jan 15 ISSN Number 1477-9129 DOI 10.1242/dev.199726 Alternate Journal Development PMCID PMC8917413 PMID 35051272 PubMedPubMed CentralGoogle ScholarBibTeXEndNote X3 XML