Endothelial Ephrin‐B2 is Essential for Arterial Vasodilation in Mice. (October 2014)

• Record Type: Journal Article
• Authors: Lin, Yuankai; Jiang, Weiya; Ng, Jennifer; Jina, Asmita; Wang, Rong A.
• Is Part Of: Microcirculation. Volume 21:Number 7(2014:Oct.)
• Page Start: 578
• Page End: 586
• Publication Date: 2014-10
• Subjects: Biological transport -- Periodicals; Microcirculation -- Physiology -- Periodicals; 612.135
• DOI: 10.1111/micc.12135
• Languages: English
• ISSNs: 1073-9688

Abstract

<abstract abstract-type="main" id="micc12135-abs-0001"> <title>Abstract</title> <sec id="micc12135-sec-0001" sec-type="section"> <title>Objective</title> <p>The cell surface protein ephrin‐B2 is expressed in arterial and not venous ECs throughout development and adulthood. Endothelial ephrin‐B2 is required for vascular development and angiogenesis, but its role in established arteries is currently unknown. We investigated the physiological role of ephrin‐B2 signaling in adult endothelium.</p> </sec> <sec id="micc12135-sec-0002" sec-type="section"> <title>Methods</title> <p>We generated adult conditional knockout mice lacking the <italic>Efnb2</italic> gene specifically in ECs and evaluated the vasodilation responses to blood flow increase and ACh in the cremaster muscle preparation by intravital microscope and in carotid artery by <italic>in vivo</italic> ultrasound.</p> </sec> <sec id="micc12135-sec-0003" sec-type="section"> <title>Results</title> <p>We found that the <italic>Efnb2</italic> conditional knockout mice were defective in acute arterial dilation. Vasodilation was impaired in cremaster arterioles in response to either increased flow or ACh, and in the carotid arteries in response to increased flow. Levels of cGMP, an effector of NO, were diminished in mutant arteries following ACh stimulation. GSNO, a donor for the vasodilator NO, alleviated the vasodilatory defects in the mutants. Immunostaining showed that a subset of ephrin‐B2 proteins colocalized with caveolin‐1, a negative regulator of eNOS.</p> </sec> <sec id="micc12135-sec-0004" sec-type="section"> <title>Conclusions</title> <p>Our data suggest that endothelial ephrin‐B2 is required for endothelial‐dependent arterial dilation and NO signaling in adult endothelium.</p> </sec> </abstract>