Stable flow-induced expression of KLK10 inhibits endothelial inflammation and atherosclerosis

Abstract

Atherosclerosis preferentially occurs in arterial regions exposed to disturbed blood flow (<i>d-flow</i>), while regions exposed to stable flow (<i>s-flow</i>) are protected. The proatherogenic and atheroprotective effects of <i>d-flow</i> and <i>s-flow</i> are mediated in part by the global changes in endothelial cell (EC) gene expression, which regulates endothelial dysfunction, inflammation, and atherosclerosis. Previously, we identified kallikrein-related peptidase 10 (<i>Klk10</i>, a secreted serine protease) as a flow-sensitive gene in mouse arterial ECs, but its role in endothelial biology and atherosclerosis was unknown. Here, we show that KLK10 is upregulated under <i>s-flow</i> conditions and downregulated under <i>d-flow</i> conditions using in vivo mouse models and in vitro studies with cultured ECs. Single-cell RNA sequencing (scRNAseq) and scATAC sequencing (scATACseq) study using the partial carotid ligation mouse model showed flow-regulated <i>Klk10</i> expression at the epigenomic and transcription levels. Functionally, KLK10 protected against <i>d-flow</i>-induced permeability dysfunction and inflammation in human artery ECs, as determined by NFκB activation, expression of vascular cell adhesion molecule 1 and intracellular adhesion molecule 1, and monocyte adhesion. Furthermore, treatment of mice in vivo with rKLK10 decreased arterial endothelial inflammation in <i>d-flow</i> regions. Additionally, rKLK10 injection or ultrasound-mediated transfection of <i>Klk10</i>-expressing plasmids inhibited atherosclerosis in <i>Apoe</i>^-/- mice. Moreover, KLK10 expression was significantly reduced in human coronary arteries with advanced atherosclerotic plaques compared to those with less severe plaques. KLK10 is a flow-sensitive endothelial protein that serves as an anti-inflammatory, barrier-protective, and anti-atherogenic factor.