Expression of nitric oxide-transporting aquaporin-1 is controlled by KLF2 and marks non-activated endothelium in vivo

  • The flow-responsive transcription factor Krüppel-like factor 2 (KLF2) maintains an anti-coagulant, anti-inflammatory endothelium with sufficient nitric oxide (NO)-bioavailability. In this study, we aimed to explore, both in vitro and in human vascular tissue, expression of the NO-transporting transmembrane pore aquaporin-1 (AQP1) and its regulation by atheroprotective KLF2 and atherogenic inflammatory stimuli. In silico analysis of gene expression profiles from studies that assessed the effects of KLF2 overexpression in vitro and atherosclerosis in vivo on endothelial cells, identifies AQP1 as KLF2 downstream gene with elevated expression in the plaque-free vessel wall. Biomechanical and pharmaceutical induction of KLF2 in vitro is accompanied by induction of AQP1. Chromosome immunoprecipitation (CHIP) confirms binding of KLF2 to the AQP1 promoter. Inflammatory stimulation of endothelial cells leads to repression of AQP1 transcription, which is restrained by KLF2 overexpression. Immunohistochemistry reveals expression of aquaporin-1 in non-activated endothelium overlying macrophage-poor intimae, irrespective whether these intimae are characterized as being plaque-free or as containing advanced plaque. We conclude that AQP1 expression is subject to KLF2-mediated positive regulation by atheroprotective shear stress and is downregulated under inflammatory conditions both in vitro and in vivo. Thus, endothelial expression of AQP1 characterizes the atheroprotected, non-inflamed vessel wall. Our data provide support for a continuous role of KLF2 in stabilizing the vessel wall via co-temporal expression of eNOS and AQP1 both preceding and during the pathogenesis of atherosclerosis.
Author:Ruud D. Fontijn, Oscar L. Volger, Tineke C. van der Pouw-Kraan, Anuradha Doddaballapur, Thomas Leyen, Josefien M. Baggen, Reinier BoonORCiDGND, Anton J. G. Horrevoets
Parent Title (English):PLoS One
Place of publication:Lawrence, Kan.
Document Type:Article
Date of Publication (online):2015/12/30
Date of first Publication:2015/12/30
Publishing Institution:Universitätsbibliothek Johann Christian Senckenberg
Release Date:2016/02/04
Issue:(12): e0145777
Page Number:13
First Page:1
Last Page:13
Copyright: © 2015 Fontijn et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited
Institutes:Medizin / Medizin
Dewey Decimal Classification:6 Technik, Medizin, angewandte Wissenschaften / 61 Medizin und Gesundheit / 610 Medizin und Gesundheit
Licence (German):License LogoCreative Commons - Namensnennung 4.0