Ambrisentan Retains Its Pro-Autophagic Activity on Human Pulmonary Artery Endothelial Cells Exposed to Hypoxia in an In Vitro Model Mimicking Diabetes

Cardiovascular comorbidities are associated with reduced treatment response in group 1 pulmonary arterial hypertension (PAH). This may result from misdiagnosis of group 2 PH, but it can also be explained as the loss of ability of pulmonary endothelial cells to respond to specific antiremodeling drugs. We evaluated the effects of high glucose (HG) and hyperosmolar stress (high mannitol, HM) on the response of human pulmonary artery endothelial cells (hPAECs) to ambrisentan (AMB), focusing on autophagy, viability, apoptosis and several microRNAs involved in pulmonary arterial remodelling. hPAECs were incubated with 30.5 mM HG or 25 mM HM, with/without 0.02 nM AMB in normoxia (Nx) or hypoxia (Hx) for 24 h. Hx reduced cell survival (p = 0.03) and autophagy (p = 0.02), an effect mimicked by HG and HM only in Nx. In Nx and Hx, AMB reverted the effect of HG, but not HM on autophagy, almost completely or partially, respectively. Compared to Nx, Hx increased the antiapoptotic miR124-3p in vehicle-treated hPAEC (p = 0.002), and induced an opposite effect on antiapoptotic and proliferative miR191-3p. In Nx, AMB induced miR124-3p in HG- (p = 0.04 vs. HG+A_Nx) and HM-treated (p < 0.0001 vs. HM+AMB_Nx) hPAECs, and miR191-3p in HM-treated hPAECs (p = 0.03). In H, A induced a similar effect on miR124-3p in hPAEC exposed to AMB+HM (p = 0.02). In hPAEC exposed to Hx, AMB retains its pro-autophagic effects in an in vitro model mimicking diabetes. miR124-3p and, to a lesser extent, miR191-3p may act as biomarkers of disease and treatment response to specific drugs in patients with PAH and diabetes.