Abstract 2028: CEPT1 Overexpression Promotes Endothelial Cell Function Through Pparα And Vegf-a

Abstract

Objectives: CEPT1, choline/ethanolamine phosphotransferase 1, is an important mediator of de novo phospholipogenesis and is essential for endothelial cell (EC) survival. CEPT1 catalyzes synthesis of phospholipids that activate the transcription factor peroxisome proliferator-activated receptor α (PPARα). We observed that CEPT1 is elevated in the endothelium of hypoxic and diseased human peripheral arterial segments. Therefore, we hypothesized that Cept1 overexpression impacts EC angiogenic function and PPARα-mediated signaling. Methods: We engineered a Cre -induced conditional, EC-specific, Cept1 overexpression model on a C57BL/6J background. Aortic rings, as well as liver and lung ECs were isolated from Cept1 fl/fl Cre - and Cept1 fl/fl Cre + mice (n=3). Aortic rings were implanted in growth-factor reduced Matrigel and microvascular sprouts were evaluated 6 days after implantation. In vitro EC proliferation and migration assay were performed. EC gene and protein expression profiles of Pppara and Vegfa , were evaluated using RT-PCR and Western blot. All experimental conditions were performed in triplicate and were analyzed using the Student’s t-test. Results: Cept1 fl/fl Cre + ECs showed significantly increased proliferation and migration (p<0.05; Fig A, B and F). Similarly, Cept1 fl/fl Cre + aortic rings demonstrated significantly higher microvascular sprouts (p<0.05; Fig C). Gene and protein expression profiling demonstrated that Cept1 fl/fl Cre + ECs had significantly increased Vegfa gene expression (p<0.05; Fig D and F). Western blot demonstrated 79% increase in VEGF-A in ECs of Cept1 fl/fl Cre + mice. In HUVECs overexpressing Cept1 , Ppara siRNA decreased EC migration (p<0.05; Fig E). Conclusion: Cept1 pro-angiogenic signaling appears to be Ppara -dependent and mediated by VEGF-A. CEPT1 content in diseased peripheral arterial segments may represent a potential compensatory mechanism for enhanced recovery during chronic limb ischemia.