The goal of this proposal is to study the effect of sympathetic innervation on the formation of 21 and 22 adrenoceptor (AR) signaling complexes in the heart. We will investigate how these complexes either facilitate or restrict receptor signaling;we will identify the structural domains of the receptors that are needed for interaction with the other components of the signaling complex;and we will identify cellular proteins that define these subtype-specific signaling complexes. 21ARs and 22ARs are prototypical G protein coupled receptors (GPCRs), the largest family of hormone and neurotransmitter receptors in the human genome. These receptors are essential for the physiologic regulation of cardiac function in response to catecholamines (adrenaline and noradrenaline) released from sympathetic nerves. Recent studies suggest that 21ARs and 22ARs play distinct roles in the pathogenesis of heart failure, a growing health problem in the United States. We have developed an experimental system to study the important interface between sympathetic nerves and the heart using co-cultures of neonatal cardiac myocytes and sympathetic neurons. Our preliminary studies show that 21ARs and 22ARs have differential subcellular targeting relative to these synapses, and that signaling complexes form at the sites of synapse formation. The following aims are designed to characterize these signaling complexes.
Aim 1. Determine the structural basis for subtype specific targeting and trafficking of 21ARs and 22ARs in cardiac myocytes.
Aim 2. Determine the functional significance of subtype-specific localization of 21ARs and 22ARs relative to sympathetic synapses.
Aim 3. Characterize protein components of the 21AR and 22AR signaling complexes in cardiac myocytes innervated by sympathetic neurons.
Aim 4. Determine the functional significance of interacting proteins identified in Aim 3 on 21AR and 22AR signaling and trafficking in cardiac myocytes, and verify their existence in signaling complexes in the adult heart. The proposed studies will provide new information about how the brain regulates heart function. We will characterize the mechanism by which noradrenaline and adrenaline released from sympathetic nerves alters heart function by activation of two specific adrenergic receptors. This research will further our understanding of the development of diseases such as heart failure and sudden death.

Agency
National Institute of Health (NIH)
Institute
National Heart, Lung, and Blood Institute (NHLBI)
Type
Research Project (R01)
Project #
5R01HL071078-07
Application #
7762717
Study Section
Biophysics of Neural Systems Study Section (BPNS)
Program Officer
Adhikari, Bishow B
Project Start
2002-09-15
Project End
2013-01-31
Budget Start
2010-02-01
Budget End
2011-01-31
Support Year
7
Fiscal Year
2010
Total Cost
$398,253
Indirect Cost
Name
Stanford University
Department
Biophysics
Type
Schools of Medicine
DUNS #
009214214
City
Stanford
State
CA
Country
United States
Zip Code
94305
Chung, Ka Young; Day, Peter W; Vélez-Ruiz, Gisselle et al. (2013) Identification of GPCR-interacting cytosolic proteins using HDL particles and mass spectrometry-based proteomic approach. PLoS One 8:e54942
Chung, Ka Young; Rasmussen, Søren G F; Liu, Tong et al. (2011) Conformational changes in the G protein Gs induced by the ?2 adrenergic receptor. Nature 477:611-5
Chen, Michael Q; Whittington, R Hollis; Day, Peter W et al. (2010) A device for separated and reversible co-culture of cardiomyocytes. Biotechnol Prog 26:1164-71
Richter, Wito; Day, Peter; Agrawal, Rani et al. (2008) Signaling from beta1- and beta2-adrenergic receptors is defined by differential interactions with PDE4. EMBO J 27:384-93
Wang, Yongyu; Lauffer, Benjamin; Von Zastrow, Mark et al. (2007) N-ethylmaleimide-sensitive factor regulates beta2 adrenoceptor trafficking and signaling in cardiomyocytes. Mol Pharmacol 72:429-39
Shcherbakova, Olga G; Hurt, Carl M; Xiang, Yang et al. (2007) Organization of beta-adrenoceptor signaling compartments by sympathetic innervation of cardiac myocytes. J Cell Biol 176:521-33
Xiang, Yang; Naro, Fabio; Zoudilova, Maria et al. (2005) Phosphodiesterase 4D is required for beta2 adrenoceptor subtype-specific signaling in cardiac myocytes. Proc Natl Acad Sci U S A 102:909-14
Xiang, Yang; Kobilka, Brian (2003) The PDZ-binding motif of the beta2-adrenoceptor is essential for physiologic signaling and trafficking in cardiac myocytes. Proc Natl Acad Sci U S A 100:10776-81