Notch activation induces endothelial cell senescence and pro-inflammatory response: Implication of Notch signaling in atherosclerosis

Objective: Notch signaling plays pivotal roles in the pathogenesis of vascular disease. However, little is known about its role in atherosclerosis. We sought to investigate the potential involvement of the Notch signaling in atherosclerosis. Methods: Expression of Notch pathway components in mouse and human aorta with or without atherosclerosis plaque was examined by immunohistochemistry. Expression of Notch target genes in young versus aged human endothelial cells (EC) was examined by PCRArray and immunoblot. In vitro loss- and gain-of-function approaches were utilized to evaluate the role of Notch signaling in inducing EC senescence and secretion of pro-inflammatory cytokines by ProteinArray. Notch gene profile was studied in 1054 blood samples of patients with coronary artery disease (CAD). Genotyping was performed using the Genome-Wide Single Nucleotide Polymorphism (SNP) Array. Results: Notch pathway components were upregulated in luminal EC at atherosclerotic lesions from mouse and human aortas. In addition, the Notch pathway was activated in aged but not young human EC. Enforced Notch activation resulted in EC senescence and significantly upregulated expression of several molecules implicated in the inflammatory response (IL-6/IL-8/IL-1α/RANTES/ICAM-1). The upregulated IL-6 was partially responsible for mediating leukocyte transendothelial migration. Genetic association analysis detected, of 82 SNPs across 6 Notch pathway genes analyzed, 4 SNPs with nominal association with CAD burden. Conclusion: Notch pathway is activated in luminal EC at atherosclerotic plaques and results in pro-inflammatory response and senescence of EC. Notch signaling may be linked to human CAD risk. These findings implicate a potential involvement of Notch signaling in atherosclerosis.