Endothelial cannabinoid CB1 receptor deficiency reduces arterial inflammation and lipid uptake in response to atheroprone shear stress

Peripherally restricted cannabinoid CB1 receptor antagonists without central side effects hold promise for treating metabolic disorders including diabetes and obesity. In atherosclerosis, the specific effects of peripheral endothelial CB1 signaling remain incompletely understood. Here, we report the expression of the CB1 encoding gene CNR1 in arterial endothelial cells of human plaques. We also show that endothelial CNR1 expression is increased by oscillatory shear stress (OSS) in human aortic endothelial cells (HAoECs) and is higher in atheroprone regions than in atheroresistant regions of murine aortas. Endothelial CB1 deficiency (Cnr1EC-KO) in atheroprone mice resulted in pronounced endothelial phenotypic changes with reduced vascular inflammation and permeability. This led to reduced plaque development with a lower lipid content in female mice, whereas attenuated plaque development, but no changes in plaque lipid content were found in males. Reduced white and brown adipose tissue mass and liver steatosis upon Cnr1EC-KO were observed in both males and females. Ex vivo imaging of female carotid arteries revealed less low density lipoprotein (Dil-LDL) uptake in Cnr1EC-KO. This was accompanied by reduced endothelial caveolin-1 (CAV1) expression, a key structural protein involved in lipid transcytosis, which was only observed in female Cnr1EC-KO mice. In vitro, pharmacological blocking with CB1 antagonist AM281 reproduced the inhibition of CAV1 expression and Dil-LDL uptake in response to atheroprone OSS in HAoECs, which was dependent on cAMP-mediated PKA activation. Conversely, the CB1 agonist ACEA increased Dil-LDL uptake and CAV1 expression in HAoECs. Chronic treatment of atherosclerotic mice with the peripheral CB1 antagonist JD-5037 reduced plaque progression and endothelial CAV1 expression in female mice. Consistent with more pronounced effects in females, HAECs treated with the estrogen receptor ligand estradiol exhibited increased CNR1 and CAV1 expression. These results support a proatherogenic role of endothelial CB1, which appears to be more pronounced in females.