(A,B) LMOD1 expression in lungs from PAH and non-PAH patients (n = 3) was determined by immunofluorescence and Western blot. Images from lung sections showed a marked decrease in LMOD1 expression (red fluorescence) in the vessel wall, primarily the media, of PAH samples compared to non-PAH group; DAPI nuclear staining (blue), (A). Western blot analysis of total lung homogenates showed a significant decrease in LMOD1 expression in PAH compared to control lung homogenates (B). (C-D) LMOD1 expression in the pulmonary artery (PA) from PAH and non-PAH patients (n = 3) was determined using immunofluorescence and Western blot analysis, respectively. Immunofluorescence images from PA sections of non-PAH samples showed expression of LMOD1 specific to the medial layer (smooth muscle layer, red fluorescence). LMOD1 expression was significantly attenuated in PAH samples compared to non-PAH group (C). Western blot analysis of total PA homogenates showed significant decreases in myocardin (MYOCD) and LMOD1 expression in PAH compared to non-PAH tissue homogenates (D). Western blot analysis of PASMCs-derived from PAH and non-PAH subjects showed decreased levels of MYOCD and LMOD1 protein in PAH group compared to non-PAH group (n = 3–5) (E). Western blot analysis of PASMCs-derived from PAH and non-PAH patients showed decreased levels of MEF2C protein in the PAH group compared to non-PAH subjects (n = 4) (F). Blots are representative; graphs depict mean ± SEM (*, p<0.05).