@article{10.1172/jci.insight.152503, author = {Prathibha R. Gajjala AND Rajesh K. Kasam AND Divyalakshmi Soundararajan AND Debora Sinner AND Steven K. Huang AND Anil G. Jegga AND Satish K. Madala}, journal = {JCI Insight}, publisher = {The American Society for Clinical Investigation}, title = {Dysregulated overexpression of Sox9 induces fibroblast activation in pulmonary fibrosis}, year = {2021}, month = {10}, volume = {6}, url = {https://insight.jci.org/articles/view/152503}, abstract = {Idiopathic pulmonary fibrosis (IPF) is a fatal fibrotic lung disease associated with unremitting fibroblast activation including fibroblast-to-myofibroblast transformation (FMT), migration, resistance to apoptotic clearance, and excessive deposition of extracellular matrix (ECM) proteins in the distal lung parenchyma. Aberrant activation of lung-developmental pathways is associated with severe fibrotic lung disease; however, the mechanisms through which these pathways activate fibroblasts in IPF remain unclear. Sry-box transcription factor 9 (Sox9) is a member of the high-mobility group box family of DNA-binding transcription factors that are selectively expressed by epithelial cell progenitors to modulate branching morphogenesis during lung development. We demonstrate that Sox9 is upregulated via MAPK/PI3K-dependent signaling and by the transcription factor Wilms’ tumor 1 in distal lung-resident fibroblasts in IPF. Mechanistically, using fibroblast activation assays, we demonstrate that Sox9 functions as a positive regulator of FMT, migration, survival, and ECM production. Importantly, our in vivo studies demonstrate that fibroblast-specific deletion of Sox9 is sufficient to attenuate collagen deposition and improve lung function during TGF-α–induced pulmonary fibrosis. Using a mouse model of bleomycin-induced pulmonary fibrosis, we show that myofibroblast-specific Sox9 overexpression augments fibroblast activation and pulmonary fibrosis. Thus, Sox9 functions as a profibrotic transcription factor in activating fibroblasts, illustrating the potential utility of targeting Sox9 in IPF treatment.}, number = {20}, doi = {10.1172/jci.insight.152503}, url = {https://doi.org/10.1172/jci.insight.152503}, }