The major objective of this research program is to provide the applicant with new and intensive training in relavant renal and whole animal physiological studies and a foundation of published work in elucidating aldosterone signaling pathways controlling ion transport criticle to renal physiology. The applicant's long-term goal is to become a successful independent investigator in molecular and cell biological research of the kidney. To achieve this goal, the applicant will be trained in the rich scientific environment of the Texas Medical Center under the close sponsorship of Dr. Bruce Kone, an expert in these areas. The scientific aims of the proposal are to model the molecular action of aldosterone on the epithelial Na+ channel in the collecting duct. Aldosterone is a major regulator of Na+ and acid-base balance and control of blood pressure.
The specific aims are to define a novel signaling cascade initiated by aldosterone, via AF9a phosphorylation by SGK1 and H3 K79 methylation by mDotla to transcriptional activation of ENaC in mIMCDS cells and to reveal AF9a and mDotl a as novel physiological targets of aldosterone in regulating ENaC transcription in vivo in mice. mIMCDS cells have been shown to respond to aldosterone and express SGK1, AF9a, mDotl a and ENaC. A wide range of molecular approaches including chromatin immunoprecipitation, real-time RTqPCFt nuclear run-on assays and renal physiological assays (ion transport and urinary electrolyte) will be applied to achieve the goals. It is anticipated that 1) AF9a will identified as an early repressed target by aldosterone action, a novel physiological substrate of SGK1, the first non-histone protein interacting with mDotla and the first protein modulating H3 K79 methylation in a targeted manner; 2) Dotla will become the first chromatin-remodeling protein that serves as an integrate component of aldosterone signaling pathway; 3) ENaC will become the first immediate downstream target of AF9a. Collectively this work will poise the applicant to be an innovative independent scientist in renal signaling and ion transport.

Agency
National Institute of Health (NIH)
Institute
National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK)
Type
Research Scientist Development Award - Research & Training (K01)
Project #
5K01DK070834-03
Application #
7242612
Study Section
Diabetes, Endocrinology and Metabolic Diseases B Subcommittee (DDK)
Program Officer
Rankin, Tracy L
Project Start
2005-06-01
Project End
2009-05-31
Budget Start
2007-06-01
Budget End
2009-05-31
Support Year
3
Fiscal Year
2007
Total Cost
$109,764
Indirect Cost
Name
University of Texas Health Science Center Houston
Department
Internal Medicine/Medicine
Type
Schools of Medicine
DUNS #
800771594
City
Houston
State
TX
Country
United States
Zip Code
77225
Zhang, Wenzheng; Yu, Zhiyuan; Wu, Hongyu et al. (2013) An Af9 cis-element directly targets Dot1a to mediate transcriptional repression of the ýýENaC gene. Am J Physiol Renal Physiol 304:F367-75
Reisenauer, Mary Rose; Anderson, Marc; Huang, Le et al. (2009) AF17 competes with AF9 for binding to Dot1a to up-regulate transcription of epithelial Na+ channel alpha. J Biol Chem 284:35659-69
Kone, Bruce C; Wenzhang, Zhang; Zhiyuan, Yu (2007) New mechanisms for transcriptional repression of ENaC And iNOS. Trans Am Clin Climatol Assoc 118:45-56
Zhang, Wenzheng; Xia, Xuefeng; Reisenauer, Mary Rose et al. (2007) Aldosterone-induced Sgk1 relieves Dot1a-Af9-mediated transcriptional repression of epithelial Na+ channel alpha. J Clin Invest 117:773-83
Zhang, Wenzheng; Xia, Xuefeng; Jalal, Diana I et al. (2006) Aldosterone-sensitive repression of ENaCalpha transcription by a histone H3 lysine-79 methyltransferase. Am J Physiol Cell Physiol 290:C936-46
Zhang, Wenzheng; Xia, Xuefeng; Reisenauer, Mary Rose et al. (2006) Dot1a-AF9 complex mediates histone H3 Lys-79 hypermethylation and repression of ENaCalpha in an aldosterone-sensitive manner. J Biol Chem 281:18059-68