COL9A1 and bronchopulmonary dysplasia: Extracellular matrix (ECM) remodeling is another important component in the pathophysiology of BPD, and RNA sequencing of fetal lungs at 24 h after LPS exposure showed significant modulation of genes related to ECM remodeling (Cxcl1) and organization, collagen synthesis (Col9a2, Col9a1, Col11a2, Col11a1), proliferative mesenchymal progenitors and matrix fibroblasts.