A6645 Sirtuin 3-mediated glycolysis enhancing during Angiotension II-induced endothelial-to-mesenchymal transition

Abstract

Objectives: Enhanced glycolysis has been recognized as a critical role in initiating endothelial to mesenchymal transition (EndMT) progression. The underlying regulators of the metabolic program in Angiotension II (Ang II)-induced EndMT remain unclear. Sirtuin 3 (SIRT3), an NAD-dependent deacetylase, is a major cellular sensor of energy metabolism and mediates adaptation responses. The present study is designed to investigate the role of SIRT3-medated glycolysis enhancing in regulating the processes of EndMT. Methods: Experiments were preformed with murine aortic endothelial cells (MAECs) which were infected with lentivirus SIRT3 shRNA, ATG5 shRNA or GFP-expressing vector. EndMT was induced by Ang II (1 μM for 24 h) and the expression of endothelial and mesenchymal markers (CD31, FSP1 and α-SMA) were detected by Western blot analysis. Results: AngII leads to impaired mitophagy flux in SIRT3-deficient ECs, accompanying marked changes in EC architecture, endothelial loss and gain of mesenchymal markers. The accumulation of damaged mitochondria during EndMT is coupled to a metabolic shift with increased lactate production and elevated expression of glycolytic enzymes, which correlates with the upregulation of acetylation of endogenous ATG5. ATG5 acetylation inhibits autophagosome maturation andinduces metabolic reprogramming. Consistent with this, en face analyses displays a marked increase in α-SMC-positive endothelial cells in SIRT3−/− mice challenged with Ang II. Further, we find that SIRT3 overexpression represses glycolysis and transition in endothelial cells. Pharmacological or genetic inhibition of glycolysis significantly attenuates α-SMA expression. Conclusion: Taken together, these findings reveal that SIRT3-deficient ECs display impaired autophagy and accelerate glycolysis and the processes of EndMT.