Hypertension Research Today is a free monthly online journal that collates and summarizes the latest research about Hypertension, including details on symptoms, diagnosis, diet, treatment, causes.

Identification of a novel polymorphism in the 3'UTR of the L-arginine transporter gene SLC7A1: contribution to hypertension and endothelial dysfunction.

Yang Z, Venardos K, Jones E, Morris BJ, Chin-Dusting J, Kaye DM

Wynn Department of Metabolic Cardiology, Baker Heart Research Institute, PO Box 6492, St Kilda Rd Central, Melbourne, VIC 8008, Australia.

BACKGROUND: Endothelial dysfunction because of reduced nitric oxide bioavailability is a key feature of essential hypertension. We have found that normotensive siblings of subjects with essential hypertension have impaired endothelial function accompanied by altered arginine metabolism. METHODS AND RESULTS: We have identified a novel C/T polymorphism in the 3'UTR of the principal arginine transporter, solute carrier family 7 (cationic amino acid transporter, y+ system), member 1 gene (SLC7A1). The minor T allele significantly attenuates reporter gene expression (P<0.01) and is impaired in its capacity to form DNA-protein complexes (P<0.05). In 278 hypertensive subjects the frequency of the T allele was 13.3% compared with 7.6% in 498 normotensive subjects (P<0.001). Moreover, the overall genotype distribution observed in hypertensives differed significantly from that in normotensives (P<0.001). To complement these studies, we generated an endothelial-specific transgenic mouse overexpressing L-arginine transporter SLC7A1. The Slc7A1 transgenic mice exhibited significantly enhanced responses to the endothelium-dependent vasodilator acetylcholine (-log EC50 for wild-type versus Slc7A1 transgenic: 6.87+/-0.10 versus 7.56+/-0.13; P<0.001). This was accompanied by elevated production of nitric oxide by isolated aortic endothelial cells. CONCLUSIONS: The present study identifies a key, functionally active polymorphism in the 3'UTR of SLC7A1. As such, this polymorphism may account for the apparent link between altered endothelial function, L-arginine, and nitric oxide metabolism and predisposition to essential hypertension.

Published 13 March 2007 in Circulation, 115(10): 1269-74.
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