Fig. 6: EC-specific deletion of INHBA ameliorates hypoxia-induced PH in mice.

a Representative right ventricle pulse waves and RVSP measurements in INHBA-flox and INHBA-ECKO mice under either normoxic or 3-week hypoxic (10% O₂) conditions (n = 6 biologically independent animals in each group for normoxia; n = 7 biologically independent animals for hypoxia flox; n = 8 biologically independent animals for hypoxia ECKO). b Fulton’s index measurements in INHBA-flox and INHBA-ECKO mice (n = 5 biologically independent animals in each group for normoxia; n = 8 biologically independent animals for hypoxia flox; n = 7 biologically independent animals for hypoxia ECKO). c Representative images of hematoxylin and eosin staining and immunohistochemistry for an EC marker (vWF; in magenta color) and SMC marker (α-SMA; in green color) with DAPI in the lungs of INHBA-fox and INHBA-ECKO mice. Arrows indicate the distal PA. Bars: 50 μm. Similar results were obtained in five biologically independent samples. d, e Quantitation of the distal PA count per 100 alveoli (d) (n = 6 biologically independent values for normoxia flox, normoxia ECKO, and hypoxia flox; n = 5 biologically independent values for hypoxia ECKO) and muscularized distal PA (e) (n = 4 biologically independent values in each group for normoxia; n = 6 biologically independent values in each group for hypoxia) in the lungs of INHBA-flox and INHBA-ECKO mice. The number of no-muscularized (N), partially muscularized (P), and fully muscularized distal arteries was counted. f Quantitative PCR for INHBA mRNA expression levels in ECs isolated from the lungs of patients with iPAH and healthy control subjects (n = 10 biologically independent cells for control; n = 9 biologically independent cells for iPAH). g ActA concentration in the culture medium of ECs isolated from the lungs of patients with iPAH and healthy control subjects (n = 17 biologically independent cells for control; n = 12 biologically independent cells for iPAH). h Quantitative PCR for INHBA mRNA expression levels in ECs isolated from the lungs of patients with iPAH (n = 3 biologically independent cells in each group) and healthy control subjects (n = 4 biologically independent cells in each group) with or without hypoxia (1% O₂) exposure for 24 h. i Tube-formation assay in PAECs treated with conditioned medium derived from iPAH-ECs or control ECs in the presence or absence of Follistatin (100 ng/mL) (n = 3 biologically independent values in each group). Bars: 200 μm. ****P < 0.0001; ***P < 0.001; **P < 0.01; *P < 0.05; #, not significant (P > 0.05). Exact P values are shown in the Source data file. Data are presented as the mean ± SEM. Two-sided Student’s t-test was used to analyze the differences between the groups in the distal PA count (d and e). One-way ANOVA with Tukey’s post hoc test for multiple comparisons was used to analyze the differences between each study group in the RVSP, Fulton index measurements, and tube-formation assay (a, b, and i). Mann–Whitney U test (two-sided) was used to analyze the differences between the groups (f–h). Two-way ANOVA with Tukey’s post hoc test for multiple comparisons was used to analyze the differences between each study group in the PA muscularization (e).