Endothelial Cell-Derived Cholesterol Crystals Promote Endothelial Inflammation in Early Atherogenesis.

Abstract

Endothelial inflammation is crucial in the initiation and progression of atherosclerosis, while cholesterol crystals (CCs) play a key role in atherogenesis. However, the effects and origination of CCs on endothelial inflammation are not well understood. In the present study, we found that CCs appeared in the subendothelial space of the partially ligated carotid artery only one week after western diet feeding, which was before immune cell infiltration. In vitro, CCs were generated by human aortic endothelial cells (HAECs) upon LDL treatment. These EC-derived CCs increased the expression of intercellular cell adhesion molecule-1 (ICAM1) and vascular cell adhesion molecule-1 (VCAM1). Mechanistic studies demonstrated that CC-induced pyroptosis was critical for endothelial inflammation. Knockdown of GSDMD inhibited CC-induced endothelial inflammation, attenuated plaque progression and decreased macrophage content. Accordingly, the inhibition of GSDMD reduced the CC-induced increase of VCAM1 and ICAM1 in HAECs. Furthermore, CC-mediated pyroptosis was found to be caspase-1 (CASP1) dependent. Inhibition of CASP1 also reduced endothelial inflammation and attenuated plaque progression. In addition, the expression of GSDMD was increased in human atherosclerotic plaques. These findings identify EC-derived CCs may be an important driving force in the pathogenesis of atherosclerosis. This study uncovered a new understanding that EC-derived CC-induced pyroptosis is a key initial factor in early atherogenesis. Targeting endothelial GSDMD or CASP1 contributes to the repression of vascular inflammation and atherogenesis. Targeting endothelial GSDMD or CASP1 contributes to the repression of vascular inflammation and atherogenesis.