G protein-coupled kinase type 4 (GRK4) gene variants (R65L, A142V, and A486V) selectively desensitizes the dopamine-1 receptor (DIR) and not the D5R, which upregulates the angiotensin type 1 receptor (ATIR). The net result of a desensitized DIR (natriuretic) and upregulated ATIR (antinatriuretic) is a net sodium reabsorption by the kidney. However, the molecular mechanisms responsible for DIR desensitization, ATIR upregulation, and the integration of these two pathways on net sodium metabolism are not well understood. We hypothesize that the membrane localization and ultimate activity of the DIR, D5R, and ATIR are regulated by oligomerization and spatial orientation via scaffolding proteins (e.g. caveolin-l (CAV1)), which ultimately regulate their interaction with intracellular second messengers. Specifically, GRK4 binds to caveolin-l (CAV1) which is interrupted by the presence of gene variants. We further hypothesize that a molecular trimeric D1R/CAV1/GRK4 association may be necessary for dopaminergic inhibition of NaKATPase activity via intracellular internalization in conjunction with adapter protein-2 (AP-2).
Specific Aim 1 will examine the spatiotemporal transregulation of the DIR, D5R, ATIR, and CAV1 and their link to intracellular second messengers. In order to increase the relevance of our studies to human physiology and pathophysiology, we will study these phenomenon in 60 human renal proximal tubular cells (RPTCs) lines that have been genotyped for GRK4 variants.
Specific Aim 2 will study spatiotemporal transregulation of the DIR, D5R, ATIR, and CAVIand their effect on the activity of the principal sodium transporters in human RPTCs NaKATPase and NHE3. The study of the effect of gene variants of GKR4 on the single RPTC physiology representing wide genetic diversity will improve our understanding of how the renal proximal tubule controls renal sodium excretion, and lead to potential novel therapeutic targets for the development of targeted and personalized antihypertensive therapeutics.

Public Health Relevance

Understanding the dynamic relationships between two key sodium regulatory pathways in the kidney is essential to deciphering the basic etiology of hypertension and salt sensitivity, major causes of common serious diseases. Since these diseases disproportionatly effect low income populations, effective targeted treatments are needed to reduce the burden on medicaid and medicare reciptients.

Agency
National Institute of Health (NIH)
Institute
National Heart, Lung, and Blood Institute (NHLBI)
Type
Research Program Projects (P01)
Project #
5P01HL074940-09
Application #
8399066
Study Section
Heart, Lung, and Blood Initial Review Group (HLBP)
Project Start
Project End
Budget Start
2013-01-01
Budget End
2013-12-31
Support Year
9
Fiscal Year
2013
Total Cost
$420,244
Indirect Cost
$84,634
Name
University of Virginia
Department
Type
DUNS #
065391526
City
Charlottesville
State
VA
Country
United States
Zip Code
22904
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
Jose, Pedro A; Felder, Robin A; Yang, Zhiwei et al. (2016) Gastrorenal Axis. Hypertension 67:1056-63
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:
Carey, Robert M (2016) Resistant Hypertension: Mineralocorticoid Receptor Antagonist or Renal Denervation? Hypertension 67:278-80
Jose, Pedro A (2016) Gastrorenal communication: sniffing and tasting. Exp Physiol 101:457-8
Yang, S; Yang, Y; Yu, P et al. (2015) Dopamine D1 and D5 receptors differentially regulate oxidative stress through paraoxonase 2 in kidney cells. Free Radic Res 49:397-410
Wang, Zhen; Guan, Weiwei; Han, Yu et al. (2015) Stimulation of Dopamine D3 Receptor Attenuates Renal Ischemia-Reperfusion Injury via Increased Linkage With Gα12. Transplantation 99:2274-84

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