The long term objective of the proposed research is to understand how G- protein coupled receptors regulate growth of cardiac myocytes. The specific problem is to determine how alpha1-adrenergic receptor (alpha1-AdrR) stimulation effects increases in cell size and myofilament organization and induces expression of embryonic (ANF) and contractile protein (MLC-2) genes in neonatal rat cardiomyocytes. The alpha1-AdrR couples to the heterotrimeric G protein G-q to regulate phospholipase C (PLC). While G- q/PLC generated signals are required or induction of ANF expression, other pathways appear to be necessary, particularly for morphological responses. These pathways will be elucidated using biochemical assays, transient expression of inhibitory proteins along with reporter genes or reporter enzymes, microinjection of cell-impermeant antibodies and inhibitors into the cell, and expression of heterologous receptors. The first specific aim is to determine the extent to which G-alpha-q and PLC-generated mediators contribute to the genetic and morphologic responses to PE. The requirement for PLC will be assessed using PLC antibodies, G-alpha-q mutants and G- alpha-q gene knockouts, and that for protein kinase C (PKC) using inhibitor peptides and antisense oligonucleotides.
In Aim #2, involvement of beta- gamma subunits and the G-12 proteins will be examined using inhibitors of beta-gamma function and G-12 antibodies.
The third aim i s to examine the involvement of the Rho family small GTP-binding proteins (particularly Rho) in alpha-1-AdrR signalling, using application or microinjection of inhibitors (RhoGDI, Botulinum C3 transferase) and expression of dominant negative and activated mutants. Whether the activity of specific phospholipases or kinases are regulated by Rho function will also be determined.
The final aim i s to map the regions of G-q-linked receptors hat couple to effectors involved in hypertrophic responses. Wild-type and chimeric mAChR, including mAChR: alpha-1-AdrR chimeras, will be expressed transiently to define receptor determinants associated with various aspects of the hypertrophic response, and cloned into or delivered with adenoviral receptor vectors for high level expression needed to measure biochemical responses. The information obtained in these studies should contribute to an understanding of the basic mechanisms of G protein receptor function, regulation of gene expression, and the control of cardiac cell growth.

Agency
National Institute of Health (NIH)
Institute
National Heart, Lung, and Blood Institute (NHLBI)
Type
Research Project (R01)
Project #
5R01HL028143-17
Application #
6183184
Study Section
Pharmacology A Study Section (PHRA)
Project Start
1982-08-01
Project End
2001-08-31
Budget Start
2000-05-06
Budget End
2001-08-31
Support Year
17
Fiscal Year
2000
Total Cost
$238,405
Indirect Cost
Name
University of California San Diego
Department
Pharmacology
Type
Schools of Medicine
DUNS #
077758407
City
La Jolla
State
CA
Country
United States
Zip Code
92093
Yu, Olivia M; Benitez, Jorge A; Plouffe, Steven W et al. (2018) YAP and MRTF-A, transcriptional co-activators of RhoA-mediated gene expression, are critical for glioblastoma tumorigenicity. Oncogene 37:5492-5507
Dusaban, Stephanie S; Chun, Jerold; Rosen, Hugh et al. (2017) Sphingosine 1-phosphate receptor 3 and RhoA signaling mediate inflammatory gene expression in astrocytes. J Neuroinflammation 14:111
Yu, Olivia M; Miyamoto, Shigeki; Brown, Joan Heller (2016) Myocardin-Related Transcription Factor A and Yes-Associated Protein Exert Dual Control in G Protein-Coupled Receptor- and RhoA-Mediated Transcriptional Regulation and Cell Proliferation. Mol Cell Biol 36:39-49
Castaldi, Alessandra; Chesini, Gino P; Taylor, Amy E et al. (2016) Sphingosine 1-phosphate elicits RhoA-dependent proliferation and MRTF-A mediated gene induction in CPCs. Cell Signal 28:871-9
Miyamoto, Shigeki; Brown, Joan Heller (2016) Drp1 and Mitochondrial Autophagy Lend a Helping Hand in Adaptation to Pressure Overload. Circulation 133:1225-7
Yu, Olivia M; Brown, Joan Heller (2015) G Protein-Coupled Receptor and RhoA-Stimulated Transcriptional Responses: Links to Inflammation, Differentiation, and Cell Proliferation. Mol Pharmacol 88:171-80
Grimm, Michael; Ling, Haiyun; Willeford, Andrew et al. (2015) CaMKII? mediates ?-adrenergic effects on RyR2 phosphorylation and SR Ca(2+) leak and the pathophysiological response to chronic ?-adrenergic stimulation. J Mol Cell Cardiol 85:282-91
Sayyah, Jacqueline; Bartakova, Alena; Nogal, Nekeisha et al. (2014) The Ras-related protein, Rap1A, mediates thrombin-stimulated, integrin-dependent glioblastoma cell proliferation and tumor growth. J Biol Chem 289:17689-98
Zhao, Xia; Ding, Eric Y; Yu, Olivia M et al. (2014) Induction of the matricellular protein CCN1 through RhoA and MRTF-A contributes to ischemic cardioprotection. J Mol Cell Cardiol 75:152-61
Xiang, Sunny Yang; Dusaban, Stephanie S; Brown, Joan Heller (2013) Lysophospholipid receptor activation of RhoA and lipid signaling pathways. Biochim Biophys Acta 1831:213-22

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