Overexpression of PlGF contributes to development of PH. (A-C) Plasma PlGF, endothelin-1 levels, and RV mass in Berk-SS mice compared with normal controls. RV mass is expressed as a ratio of RV wall weight/left ventricle wall (LV) + septum (S) wet weights; n = 4 to 8 animals/group. (D) Lentivirus vector constructs designed to express PlGF or GFP cDNA under the control of β-globin gene promoter and hypersensitive (HS) sites 2, 3, and 4 of the β-globin locus control region. (E-G) Plasma PlGF and endothelin-1 levels in normal C57Bl/6 mice that express either PlGF or GFP from erythroid cells and RV mass, in these mice; n = 4 to 8 animals/group. (H-I) Cardiac MRI on sβ-GFP and sβ-PLGF-expressing mice at 16 weeks; n = 4. A representative view of the RV at the same plane in sβ-GFP and sβ-PLGF mice is shown; RV wall (arrow) hypertrophy and higher RV end-diastolic volume (not shown) were seen qualitatively. (J) Immunostaining of lungs for smooth muscle actin of 1 representative sβ-GFP mouse and 3 sβ-PlGF mice (shown as green fluorescence). All bar graphs represent mean and SEM; comparisons were made using t tests. Fluorescence images were obtained using a Leica DMI 6000 Fluorescence microscope with a 20× objective. Image acquisition was done using OpenLab Version 5.5 (Improvision).