Abstract 11407: E-Cigarettes Induce Dysregulation of Autophagy Leading to Endothelial Dysfunction in an Ipsc Model of Pulmonary Arterial Hypertension

Abstract

Introduction: Given the increasing popularity of electronic-cigarettes (e-cigs), it is imperative to evaluate the potential health risks of e-cigs especially in users with pre-existing health concerns. Although we have recently demonstrated that acute exposure to e-cig exacerbates endothelial dysfunction, a prominent feature of pulmonary arterial hypertension (PAH), it is currently unknown whether the use of e-cig represents an even higher risk factor in PAH patients. The aim of the present study is to assess if differential susceptibility exists between healthy and PAH patients following e-cig exposure and mechanisms contributing to it. Methods and Results: Using patient-specific induced pluripotent stem cells (iPSCs) derived from both PAH patients and healthy controls, we showed that PAH iPSC-derived endothelial cells (iPSC-ECs) exhibited increased susceptibility against e-cig exposure compared to healthy iPSC-ECs leading to significantly decreased cell viability, increased reactive oxygen species generation and apoptosis, and reduced tube formation and migration. Transcriptomic analyses revealed that differential expression of AKT3 may be responsible for triggering enhanced autophagic flux impairment in PAH iPSC-ECs compared to healthy iPSC-ECs which underlies increased susceptibility upon e-cig exposure. Consistent with sequencing data, western blot confirmed that AKT3 level was decreased in PAH iPSC-ECs following e-cig exposure and AKT3 proteasomal degradation was mediated by K48-linked ubiquitination. Moreover, knockdown of AKT3 in healthy iPSC-ECs significantly induced autophagic flux impairment and increased endothelial dysfunction and these vascular toxicities were further increased when exposed to e-cig, thus mimicking the PAH cell phenotype after e-cig exposure. Finally, rapamycin treatment reversed e-cig-induced decreased AKT3 level, endothelial dysfunction, and autophagy impairment in PAH iPSC-ECs. Conclusions: Taken together, these data suggest a potential link between autophagy and Akt3-mediated increased susceptibility to e-cig in PAH.