NOTCH1 is a mechanosensor in adult arteries

Julia J Mack,Timothy F Lane,Carlos O Lizama,William M Jones,Mohamad Navab,Trent Su,Thomas Q De Aguiar Vallim,Ann C Zovein,Louis Bouchard ,Yun Fang,Guido C Faas,Milagros C Romay ,Raquel Aragón ,Anaïs Briot ,Austin I Mcdonald,Hannah Sunshine,Chien-Nan Kuo ,Brian J Archer,Thiago Mosqueiro ,Elizabeth J Tarling,Alan M Fogelman,M Luisa Iruela‐Arispe

doi:10.1038/s41467-017-01741-8

Abstract

Endothelial cells transduce mechanical forces from blood flow into intracellular signals required for vascular homeostasis. Here we show that endothelial NOTCH1 is responsive to shear stress, and is necessary for the maintenance of junctional integrity, cell elongation, and suppression of proliferation, phenotypes induced by laminar shear stress. NOTCH1 receptor localizes downstream of flow and canonical NOTCH signaling scales with the magnitude of fluid shear stress. Reduction of NOTCH1 destabilizes cellular junctions and triggers endothelial proliferation. NOTCH1 suppression results in changes in expression of genes involved in the regulation of intracellular calcium and proliferation, and preventing the increase of calcium signaling rescues the cell–cell junctional defects. Furthermore, loss of Notch1 in adult endothelium increases hypercholesterolemia-induced atherosclerosis in the descending aorta. We propose that NOTCH1 is atheroprotective and acts as a mechanosensor in adult arteries, where it integrates responses to laminar shear stress and regulates junctional integrity through modulation of calcium signaling.

Highlights

Endothelial cells transduce mechanical forces from blood flow into intracellular signals required for vascular homeostasis
These findings indicate that NOTCH1 signaling is required in adult arteries to interpret hemodynamic forces and initiate appropriate biological responses required for vascular homeostasis and atheroprotection
Fluorescence imaging revealed a two-fold increase in GFP signal in cultures under laminar flow compared to static conditions (Fig. 1c); this correlated with nuclear presence of NOTCH1 protein (Supplementary Fig. 1b)

Summary

Introduction

Endothelial cells transduce mechanical forces from blood flow into intracellular signals required for vascular homeostasis. NOTCH1 suppression results in changes in expression of genes involved in the regulation of intracellular calcium and proliferation, and preventing the increase of calcium signaling rescues the cell–cell junctional defects. Laminar shear stress induces elongation of endothelial cells[5,6], suppression of endothelial cell proliferation, redistribution of focal adhesions, reassembly of junctional complexes, and cytoskeletal organization[7,8] These cellular responses are complex and require both shear stress sensors and a robust cohort of effector molecules that coordinate rapid changes and physiological adaptations. Our results further reveal that NOTCH1 is required to maintain junctional integrity, promote cell elongation in response to flow, and prevent atherosclerosis in the context of hypercholesterolemia Overall, these findings indicate that NOTCH1 signaling is required in adult arteries to interpret hemodynamic forces and initiate appropriate biological responses required for vascular homeostasis and atheroprotection

Methods

Results

Conclusion