The applicant proposes to study the b-adrenergic receptor-stimulatory GTP binding protein-adenylyl cyclase (AC) pathway in heart failure. b-adrenergic agonist stimulation increases intracellular cAMP in cardiac myocytes, activating protein kinase A which augments contractile function. In heart failure, despite increased sympathetic drive, cardiac function remains depressed. It has been established that altered b-receptor mediated signalling occurs in heart failure; changes include a reduction in myocardial b-receptor-stimulated cAMP production and decreased b1- receptor number. Nevertheless, there are two areas, potentially quite important in the pathogenesis of heart failure, that have received little attention: 1) the importance of AC content and catalytic function during the development of heart failure; and 2) the role of GTP binding receptor kinase (GRK) in myocardial b-receptor desensitization and the temporal regulation of their expression in the failing heart. The applicant proposes first to determine the alterations in AC isoforms and G protein receptor kinase expression during the development of heart failure. These studies will provide information regarding the specific abnormalities underlying b-receptor desensitization in heart failure, and lay the foundation for subsequent studies designed to determine mechanisms for these changes. The applicant will examine the role of AC isoform and GRK in b-receptor mediated signalling by altering their gene expression in cardiac myocytes in vitro and in vivo. Using an animal model of dilated systolic heart failure, the applicant will isolate cardiac myocytes from the left ventricle, and apply biochemical and molecular approaches to define and altered adrenergic signalling. The proposed studies will define the manner in which elements of b-receptor signalling are altered during the development of heart failure and will establish the importance of these elements in regulating b-receptor mediated cAMP responsiveness in cardiac myocytes. The applicant proposes to study the mechanism for altered myocardial b-receptor signalling transduction in heart failure by examining the regulatory mechanisms of two of the key elements of the b-receptor signalling pathway, AC and GRK. The applicant will combine molecular biology and integrated physiology approaches to define the roles of AC and GRK for b-receptor desensitization in vitro and in vivo.

Agency
National Institute of Health (NIH)
Institute
National Heart, Lung, and Blood Institute (NHLBI)
Type
First Independent Research Support & Transition (FIRST) Awards (R29)
Project #
5R29HL058166-04
Application #
6030813
Study Section
Cardiovascular and Pulmonary Research A Study Section (CVA)
Project Start
1996-08-01
Project End
2000-06-30
Budget Start
1999-07-01
Budget End
2000-06-30
Support Year
4
Fiscal Year
1999
Total Cost
Indirect Cost
Name
University of Louisville
Department
Physiology
Type
Schools of Medicine
DUNS #
City
Louisville
State
KY
Country
United States
Zip Code
40292
Pass, J M; Zheng, Y; Wead, W B et al. (2001) PKCepsilon activation induces dichotomous cardiac phenotypes and modulates PKCepsilon-RACK interactions and RACK expression. Am J Physiol Heart Circ Physiol 280:H946-55
Li, R C; Ping, P; Zhang, J et al. (2000) PKCepsilon modulates NF-kappaB and AP-1 via mitogen-activated protein kinases in adult rabbit cardiomyocytes. Am J Physiol Heart Circ Physiol 279:H1679-89
Takeishi, Y; Ping, P; Bolli, R et al. (2000) Transgenic overexpression of constitutively active protein kinase C epsilon causes concentric cardiac hypertrophy. Circ Res 86:1218-23
Ping, P; Takano, H; Zhang, J et al. (1999) Isoform-selective activation of protein kinase C by nitric oxide in the heart of conscious rabbits: a signaling mechanism for both nitric oxide-induced and ischemia-induced preconditioning. Circ Res 84:587-604
Ping, P; Zhang, J; Zheng, Y T et al. (1999) Demonstration of selective protein kinase C-dependent activation of Src and Lck tyrosine kinases during ischemic preconditioning in conscious rabbits. Circ Res 85:542-50
Ping, P; Zhang, J; Cao, X et al. (1999) PKC-dependent activation of p44/p42 MAPKs during myocardial ischemia-reperfusion in conscious rabbits. Am J Physiol 276:H1468-81
Qiu, Y; Ping, P; Tang, X L et al. (1998) Direct evidence that protein kinase C plays an essential role in the development of late preconditioning against myocardial stunning in conscious rabbits and that epsilon is the isoform involved. J Clin Invest 101:2182-98
Bolli, R; Dawn, B; Tang, X L et al. (1998) The nitric oxide hypothesis of late preconditioning. Basic Res Cardiol 93:325-38
Ping, P; Zhang, J; Qiu, Y et al. (1997) Ischemic preconditioning induces selective translocation of protein kinase C isoforms epsilon and eta in the heart of conscious rabbits without subcellular redistribution of total protein kinase C activity. Circ Res 81:404-14