Endothelial Jag1-RBPJK signaling promotes inflammatory leukocyte recruitment and atherosclerosis

Aim: To determine the role of NOTCH during the response-to-injury and subsequent chronic inflammatory process of the arterial wall underlying atherosclerosis. Methods and results: We have generated an endothelial-specific RBPJK depleted mice using the Cdh5 cadherin promoter (ApoE-/-;RBPJflox/flox;Cdh5- CreERT). Endothelial-specific deletion of the Notch effector RBPJK or systemic deletion of the Notch1 receptor in athero-susceptible ApoE-/- mice fed a HC diet for 6 weeks resulted in reduced atherosclerosis in the aortic arch and sinus. Intravital microscopy revealed decreased leukocyte rolling on the endothelium of ApoE-/-;RBPJflox/flox;Cdh5- CreERT, that correlated with the lesser presence of leukocyts and macrophages in the vascular wall. Consistent with this, transcriptome analysis revealed that proinflammatory and endothelial activation pathways were downregulated in atherosclerotic tissue of RBPJk-mutant mice.. Jagged1 signaling upregulation in endothelial cells promotes the physical interaction and nuclear translocation of the intracellular domain of the Notch1 receptor (N1ICD) with NF-kB,. This N1ICD and NF-kB interaction is required for reciprocal transactivation of target genes including vascular cell adhesion molecule-1 (Vcam1). Conclusions: Notch signaling pathway inactivation decreases leukocyte rolling, thereby preventing endothelial dysfunction and vascular inflammation. Thus attenuating Notch signaling may constitute a useful therapeutic strategy for atherosclerosis. Key words: atherosclerosis, endothelium, signaling pathways, Notch, NF-kB, transcriptional regulation Overall design: RNA was isolated from the aortic arches of three ApoE-/-;RBPJflox/flox and three ApoE-/-; RBPJflox/flox;Cdh5-CreERTmice

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Nus M, Martínez-Poveda B, MacGrogan D, Chevre R, D'Amato G, Sbroggio M, Rodríguez C, Martínez-González J, Andrés V, Hidalgo A, de la Pompa JL