View Abstract

A4201 - Alpha-EnolaseInhibition Reverses Experimental Pulmonary Hypertension Via the AMPK-Akt-GSK3β Pathway
Author Block: J. Dai1, Q. Zhou1, J. Chen2, M. L. Rexius-Hall3, J. Rehman4, G. Zhou1; 1Pediatrics, University of Illinois at Chicago, Chicago, IL, United States, 2Dept of Medicine, Univ of Illinois at Chicago, Chicago, IL, United States, 3Bioengineering, University of Illinois at Chicago, Chicago, IL, United States, 4Pharmacology, University of Illinois at Chicago, Chicago, IL, United States.
Rationale: Recent studies suggest that a metabolic shift towards an increased glycolysis in pulmonary artery smooth muscle cells (PASMC) plays an important role in the pathogenesis of pulmonary arterial hypertension (PAH), however, the underlying molecular mechanisms are not fully understood. Our study aims to understand the regulatory role of a glycolytic enzyme, α-enolase (ENO1), in the metabolic reprogramming and phenotype switch in PASMC.
Methods: We investigated the expression levels of ENO1 in both human PAH patients and experimental pulmonary hypertension (PH) animal models. We stably silenced ENO1 by infecting PASMC by lentivirus encoding shRNAs targeting ENO1 or overexpressed ENO1 by transfecting pCMV3-ENO1-GFP to PASMC, and examined PASMC proliferation, differentiation, and apoptotic resistance using many biological approaches including Western-blotting, BrdU assay, and TUNEL assay. The metabolic changes in the PASMC after silencing or inhibition of ENO1 were also studied using Seahorse assay. To test the therapeutic effect of ENO1 inhibition in vitro, we adopted a hypoxia-induced murine model of PH and a Sugen/hypoxia-induced rat model of PH combined with ENOblock (an inhibitor of Enolase) treatment.
Results: We found that ENO1 levels were elevated in the PASMC isolated from patients with PAH and in whole lungs in experimental PH rodents. The silencing or inhibition of ENO1 inhibited cell proliferation and de-differentiation, and induced apoptosis in PASMC, whereas over-expression of ENO1 promoted a synthetic, de-differentiated, and apoptotic-resistant phenotype, through the activation of an AMPK-Akt-GSK3β pathway. The silencing of ENO1 prevented the hypoxia-induced metabolic shift from mitochondrial respiration to glycolysis in PASMC. Moreover, the inhibition of ENO1 by ENOblock significantly reversed hypoxia-induced PH in mice and Sugen/hypoxia-induced PH in rats, indicating that ENO1 is a potential therapeutic target for PAH.
Conclusions: Our results provide the first evidence that ENO1 plays a critical role in the development of PH via the activation of the AMPK-Akt-GSK3β axis and the metabolic shift, thus representing a novel therapeutic target for PAH. Support: NIH HL 123804.