Reactive oxygen species (ROS), notably superoxide anion (O2-) in blood vessels increases their reactivity and tone in hypertension. The kidney plays the predominant role in long-term BP regulation. Renal mechanisms of hypertension center on an increased reactivity or tone of the afferent arteriole which limits the transmission of pressure into the kidney and hence increases the set point of BP regulation together with increased release of renin and an increased re-absorption of NaCl by the tubules which underlies salt sensitivity. The focus of this proposal is on the roles of ROS in renal mechanism of hypertension. We have assembled an interactive group of integrative, microvascular and micropuncture physiologists and molecular and cellular biologist to tackle this problem. Project 1 will center on the role of ROS in modulating myogenic responses (MRs) of the mouse afferent arteriole. It compares responses in normal mice, where ROS generation enhanced MRs and the reduced renal mass model of chronic kidney disease and the angiotensin infusion model of hypertension where ROS impaired MRs. It combines direct measures of MR in isolated perfused afferent arterioles with gene arrays and RNA seq analyses on these microvessels and fluorescence quantitation of ROS, and Ca2+ using knockout and transgenic mice or mice with single kidney gene transfection or deletion. Project 2 will investigate a new paradigm of growth-factor related oxidative stress and hypertension using a mouse model of inducible activation of basic fibroblast growth factor and its interaction with specific FGF molecules and receptors. Studies combine BP and afferent arteriolar reactivity to angiotensin with cellular and molecular studies of the signaling mechanism and their interaction with ROS. Project 3 will investigate the molecular mechanisms of defense against oxidative stress in the proximal tubule that are coordinated by the dopamine D2 receptors. The new hypothesis is that D2-R signaling enhances paraoxygenase-2 which activates a transcriptional redox-regulating pathways initiated by DJ2 to inhibit NADPH oxidase-induced ROS. These are supported by the Administrative, Animal and Bioanalytical Cores.

Public Health Relevance

Oxidative stress accompanies hypertension, chronic kidney disease and major cardiovascular risk factors but the mechanisms that link these together in blood vessels and the kidneys are poorly understood. The goal of this work is to understand the role of oxidative stress in hypertension and its consequences and thereby to provide a rational basis for new forms of prevention or treatment. (End of Abstract)

Agency
National Institute of Health (NIH)
Institute
National Heart, Lung, and Blood Institute (NHLBI)
Type
Research Program Projects (P01)
Project #
2P01HL068686-11A1
Application #
8414538
Study Section
Special Emphasis Panel (ZHL1-PPG-S (O1))
Program Officer
OH, Youngsuk
Project Start
2001-09-30
Project End
2018-01-31
Budget Start
2013-02-15
Budget End
2014-01-31
Support Year
11
Fiscal Year
2013
Total Cost
$1,863,014
Indirect Cost
$526,061
Name
Georgetown University
Department
Internal Medicine/Medicine
Type
Schools of Medicine
DUNS #
049515844
City
Washington
State
DC
Country
United States
Zip Code
20057
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Huang, Ji-Yun; Li, Li-Tao; Wang, Huan et al. (2014) In vivo two-photon fluorescence microscopy reveals disturbed cerebral capillary blood flow and increased susceptibility to ischemic insults in diabetic mice. CNS Neurosci Ther 20:816-22

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