Bone morphogenic protein receptor 2 (BMPR2) expression is depleted in idiopathic pulmonary fibrosis (IPF). A: lung sections double immunofluorescently (IF) stained for BMPR2 (violet/purple signals) and α-smooth muscle actin (αSMA; green signals) and counterstained with DAPI (white/gray signals) from normal lung tissue (left) or patients with IPF (top right) or IPF + PH (bottom left). Scale bar represents 100 μm. B: immunoblots for BMPR2, P-SMAD 1/5/8, P-SMAD 2/3, and GAPDH from isolated lung tissue from normal donor tissue, or lung explants from patients with IPF or IPF+PH. C: densitometries from immunoblots for BMPR2, P-SMAD 1/5/8, and P-SMAD 2/3 normalized to GAPDH. *P ≤ 0.05, comparisons between normal and IPF or IPF+PH.