Leukocyte specific protein-1 modulates expression and activity of endothelial nitric oxide synthase

Abstract

Endothelial dysfunction is characteristic feature of many cardiovascular diseases and risk factors such as diabetes, coronary artery disease and hypertension. Recent genome wide association studies have identified polymorphism in human leukocyte-specific protein 1 (LSP1) gene to be associated with development of essential hypertension in humans. Since endothelial dysfunction in hypertension is almost invariably accompanied by alteration in endothelial nitric oxide synthase (eNOS) expression or impairment of NO-dependent vasodilation, we hypothesize that LSP1 has a role in endothelial function via modulation of expression and function of eNOS. We sought to define the role of endothelial LSP1 in regulation of eNOS utilizing in-vitro endothelial cell culture model and LSP1 KO mice. Here we report the novel role of human LSP1 in mediating basal eNOS expression in human macrovascular endothelial cells. Using CRISPR/Cas9 mediated genomic editing to mutate human LSP1 gene and obtain LSP1 deficient endothelial cells, we have demonstrated that transient depletion of LSP1 has induced marked downregulation of eNOS expression, and considerable decrease in nitric oxide synthesis. In addition, LSP1 gain of function via adenovirus mediated overexpression enhances expression of eNOS. We have also revealed using coimmunoprecipitation and confocal microscopy that eNOS and LSP1 associate with each other under basal physiological conditions. Furthermore, LSP1 deficiency in mice induced significant upregulation of eNOS and eNOS uncoupling, associated with enhanced susceptibility of eNOS to proteolytic degradation. Our data clearly propose the novel and the crucial role of endothelial LSP1 in regulation of basal eNOS expression within human endothelial cells and mice cardiovascular tissues.