High sodium intake, independent of blood pressure, is associated with increased cardiovascular risk. However, the genetic cause(s) of salt sensitivity is not known. The definitive evidence to link genes to complex diseases, such as hypertension and salt sensitivity is the swapping of one phenotype for another. G protein-coupled receptor kinase 4 (GRK4) is the only gene postulated as causal of hypertension that fulfills this criterion, i.e., GRK4 gene variants produce salt sensitivity and hypertension in mice. GRK43 142V transgenic mice develop salt-resistant hypertension while GRK43 486V transgenic mice develop salt-sensitive hypertension. Depending upon the genetic background, overexpression of GRK43 wild type converts a salt- sensitive mouse (C57BL/6J) to a salt-resistant mouse while overexpression of GRK43 486V converts a salt- resistant mouse (SJL/J) to salt-sensitive mouse. The overall objective is to test the hypothesis that human GRK43 wild type imparts salt resistance while human GRK43 486V causes salt-sensitive hypertension.
Aim 1 will test the hypothesis that human GRK43 wild type causes salt resistance by facilitating sodium excretion. This change in phenotype is due, in part, to human GRK43 wild type differential regulation of GPCRs (e.g., D1R and AT1R) involved in the control of renal NaCl transport and blood pressure.
Aim 2 will test the hypothesis that human GRK43 486V causes salt-sensitive hypertension, in part, by impairing renal D1R function and enhancing AT1R expression. The effect of knockout of GRK4 and targeted gene replacement with human GRK43 wild type gene and variants (486V) in mice on the regulation of renal sodium excretion and blood pressure will be studied. These studies will enable the deciphering of the mechanism of salt sensitivity and its impact on blood pressure. A modest reduction in salt intake in children, adolescents, and adults results in an immediate decrease in blood pressure, with long term benefits. However, dietary sodium restriction may not be beneficial to all. Lifestyle changes lower blood pressure and reduces cardiovascular risk but motivation is a problem. Results from these studies may be important in formulating diagnostic tests, drug therapy (pharmacogenomics) and lifestyle modification.

Public Health Relevance

Variants of a gene called GRK4 predict with 70-90% accuracy that blood pressure will rise with increased salt intake. Diuretics are more effective in lowering blood pressure in individuals with variants of this gene. Results from these studies will be beneficial in the formulation of diagnostic tests, as well as drug therapy (pharmacogenomics) and lifestyle modification.

Agency
National Institute of Health (NIH)
Institute
National Heart, Lung, and Blood Institute (NHLBI)
Type
Research Project (R01)
Project #
7R01HL092196-05
Application #
8266339
Study Section
Hypertension and Microcirculation Study Section (HM)
Program Officer
OH, Youngsuk
Project Start
2008-08-01
Project End
2013-03-31
Budget Start
2012-04-01
Budget End
2013-03-31
Support Year
5
Fiscal Year
2012
Total Cost
$379,913
Indirect Cost
$132,413
Name
University of Maryland Baltimore
Department
Internal Medicine/Medicine
Type
Schools of Medicine
DUNS #
188435911
City
Baltimore
State
MD
Country
United States
Zip Code
21201
Wang, Zheng; Zeng, Chunyu; Villar, Van Anthony M et al. (2016) Human GRK4γ142V Variant Promotes Angiotensin II Type I Receptor-Mediated Hypertension via Renal Histone Deacetylase Type 1 Inhibition. Hypertension 67:325-34
Jose, Pedro A; Yang, Zhiwei; Zeng, Chunyu et al. (2016) The importance of the gastrorenal axis in the control of body sodium homeostasis. Exp Physiol 101:465-70
Sanada, H; Yoneda, M; Yatabe, J et al. (2016) Common variants of the G protein-coupled receptor type 4 are associated with human essential hypertension and predict the blood pressure response to angiotensin receptor blockade. Pharmacogenomics J 16:3-9
Liu, Tianbing; Konkalmatt, Prasad R; Yang, Yu et al. (2016) Gastrin decreases Na+,K+-ATPase activity via a PI 3-kinase- and PKC-dependent pathway in human renal proximal tubule cells. Am J Physiol Endocrinol Metab 310:E565-71
Jose, Pedro A; Felder, Robin A; Yang, Zhiwei et al. (2016) Gastrorenal Axis. Hypertension 67:1056-63
Natarajan, Aruna R; Eisner, Gilbert M; Armando, Ines et al. (2016) The Renin-Angiotensin and Renal Dopaminergic Systems Interact in Normotensive Humans. J Am Soc Nephrol 27:265-79
Zhang, Yanrong; Jiang, Xiaoliang; Qin, Chuan et al. (2016) Dopamine D2 receptors' effects on renal inflammation are mediated by regulation of PP2A function. Am J Physiol Renal Physiol 310:F128-34
Konkalmatt, Prasad R; Asico, Laureano D; Zhang, Yanrong et al. (2016) Renal rescue of dopamine D2 receptor function reverses renal injury and high blood pressure. JCI Insight 1:
Jose, Pedro A (2016) Gastrorenal communication: sniffing and tasting. Exp Physiol 101:457-8
Chen, Ken; Deng, Kun; Wang, Xiaoyan et al. (2015) Activation of D4 dopamine receptor decreases angiotensin II type 1 receptor expression in rat renal proximal tubule cells. Hypertension 65:153-60

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