Abstract 159: Endothelial Fatty Acid-binding Proteins Contribute To The Pathogenesis Of Pulmonary Hypertension

Abstract

Pulmonary arterial hypertension (PAH) is a devastating disease characterized by obliterative vascular remodeling and persistent increase of vascular resistance, leading to right heart failure. Understanding the cellular and molecular mechanisms will help develop novel therapeutic approaches for PAH patients. Objectives: To determine whether upregulation of fatty-acid binding protein 4 and 5 (FABP4/5) is critical in pathogenesis of PAH. Methods: FABP4/5 expression was examined in PA endothelial cells (PAECs) and lung tissues from patients with PAH. Plasma proteome analysis was performed in human PAH samples. Echocardiography, hemodynamics, histology, and immunostaining were performed to evaluate the lung and heart PH phenotypes in Egln1 Tie2Cre (CKO) mice and Egln1 Tie2Cre /Fabp4-5 -/- (TKO) mice. Results: Both FABP4 and FABP5 were highly induced in ECs of CKO mice and PAECs from IPAH patients. Plasma levels of FABP4/5 were upregulated in IPAH patients and directly correlated with severity of hemodynamics and biochemical parameters. Genetic deletion of Fabp4-5 in CKO mice caused a reduction of right ventricular systolic pressure (RVSP) and RV hypertrophy, attenuated pulmonary vascular remodeling and prevented the right heart failure. Fabp4/5 deletion also normalized EC glycolysis, reduced ROS and HIF-2α expression, and decreased aberrant EC proliferation in CKO lungs. Conclusions: PH causes aberrant expression of FABP4/5 in pulmonary ECs which leads to enhanced EC glycolysis and hyperproliferation, contributing to the accumulation of arterial ECs and vascular remodeling and exacerbating the disease.