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 CB1 signaling in vascular endothelial cells (ECs) remain incompletely understood.We performed en face in situ hybridization of Cnr1 in murine aortas, revealing a significantly increased expression of the CB1 encoding gene in ECs within atheroprone compared to atheroresistant regions. In vitro, CNR1 was upregulated by oscillatory shear stress in human aortic endothelial cells (HAoECs). Endothelial CB1 deficiency (Cnr1EC-KO) in female mice on atherogenic background resulted in pronounced endothelial phenotypic changes, with reduced vascular inflammation and permeability. This translated into attenuated plaque development with reduced lipid content as well as reduced white and brown adipose tissue mass and liver steatosis. Ex vivo imaging of carotid arteries via two-photon microscopy revealed less DIL-LDL uptake in Cnr1EC-KO. This was accompanied by a significant reduction of aortic endothelial caveolin-1 (CAV1) expression, a key structural protein involved in lipid transcytosis in female Cnr1EC-KO mice. In vitro, pharmacological blocking with CB1 antagonist AM281 reproduced the inhibition of CAV1 expression and LDL uptake in response to atheroprone shear stress in human aortic endothelial cells (HAoECs), which was dependent on cAMP-mediated PKA activation. Conversely, the CB1 agonist ACEA increased DIL-LDL uptake and CAV1 expression in HAoECs. Finally, treatment of atherosclerotic mice with the peripheral CB1 antagonist JD-5037 reduced plaque progression, CAV1 and endothelial adhesion molecule expression in female mice. These results confirm an essential role of endothelial CB1 to the pathogenesis of atherosclerosis. Overall design: To globally assess the transcriptomic profile regulated by endothelial CB1 signaling