Ambrisentan retains its pro-autophagic activity on human pulmonary artery endothelial cells exposed to hypoxia in an in vitro model mimicking diabetes

Abstract Cardiovascular comorbidities are associated with reduced treatment response in group 1 pulmonary arterial hypertension (PAH). Often this epidemiological evidence results 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 the endothelin receptor antagonist ambrisentan (AMB), focusing on autophagy, viability, 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 A 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, A 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, although not statistically significant. In Nx, AMB induced miR124-3p in HG- (p=0. 04 vs HG+ANx) and HM-treated (p0. 0001 vs HM+AMBNx) hPAECs, and miR191-3p in HM-treated hPAECs (p=0. 03). In H, A induced a similar effect on miR124-3p but not miR191-3p in hPAEC exposed to AMB+HM (p=0. 02). Conclusions: 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. Figure