G protein-coupled receptors (GPCRs) play critical roles in physiology, pathophysiology, and organismal development and they are the target of a large fraction of clinically used drugs. Understanding factors that modulate signaling through GPCRs is critical to the full knowledge of signal transduction mechanisms and how they can go wrong in disease. Furthermore, such modulatory mechanisms represent interesting potential drug targets. In the present proposal, we continue to explore the role of Regulators of G protein Signaling (RGS proteins) in physiology, development, and pathophysiology to understand basic signaling mechanisms and to assess the potential of RGS-targeted drugs in the treatment of important medical conditions. This work focuses on two novel mouse models in which RGS-mediated control of the Gi/o signaling pathways is lost. These RGS- insensitive (GaG184S) knock-in models result in enhanced Gai2 and Gao signaling and the mice exhibit an array of interesting phenotypes.
Aims 1 &2 assess the role of RGS proteins and Gai2 signaling in the heart. The RGSi Gai2 mice show protection against ischemia-reperfusion injury but also show worsened heart failure in catecholamine-induced and genetic heart failure models.
The aims examine the differential contribution of Gai2 signaling in myocytes and fibroblasts in these two processes and address the mechanisms and specific RGS proteins involved.
Aim 3 studies the relative contributions of Gao and Gai2 in GABA function and seizure susceptibility.
Aim 4 examines functions of the enigmatic Gao protein. The GaoG184S mice in which Gao signaling is enhanced, show neonatal lethality in homozygotes - virtually none survive past 24 hours - and heterozygotes show a strain-dependent adult lethality at about 15-25 weeks of age.
This aim will use genetic methods to understand the unexpected adult lethality. This should provide novel insights into sudden death syndromes as well as uncovering novel potential Gao effector signaling mechanisms.

Public Health Relevance

Project Narrative A key goal in pharmacology is to create medicines that produce desirable therapeutic effects while minimizing side effects. In this project, we explore signaling pathways inside heart cells that can protect against injury from heart attacks and inside brain cells that can suppress seizures. By improving those therapeutically useful signals at the expense of signals leading to side effects, we can produce better medicines or can make existing medicines better tolerated.

Agency
National Institute of Health (NIH)
Institute
National Institute of General Medical Sciences (NIGMS)
Type
Research Project (R01)
Project #
5R01GM039561-24
Application #
8307912
Study Section
Special Emphasis Panel (ZRG1-CB-J (03))
Program Officer
Dunsmore, Sarah
Project Start
1988-12-01
Project End
2014-07-31
Budget Start
2012-08-01
Budget End
2013-07-31
Support Year
24
Fiscal Year
2012
Total Cost
$586,111
Indirect Cost
$179,462
Name
University of Michigan Ann Arbor
Department
Pharmacology
Type
Schools of Medicine
DUNS #
073133571
City
Ann Arbor
State
MI
Country
United States
Zip Code
48109
Sjögren, Benita; Parra, Sergio; Atkins, Kevin B et al. (2016) Digoxin-Mediated Upregulation of RGS2 Protein Protects against Cardiac Injury. J Pharmacol Exp Ther 357:311-9
Evelyn, Chris R; Lisabeth, Erika M; Wade, Susan M et al. (2016) Small-Molecule Inhibition of Rho/MKL/SRF Transcription in Prostate Cancer Cells: Modulation of Cell Cycle, ER Stress, and Metastasis Gene Networks. Microarrays (Basel) 5:
Parra, Sergio; Huang, Xinyan; Charbeneau, Raelene A et al. (2014) Conditional disruption of interactions between Gαi2 and regulator of G protein signaling (RGS) proteins protects the heart from ischemic injury. BMC Pharmacol Toxicol 15:29
Lamberts, Jennifer T; Smith, Chelsea E; Li, Ming-Hua et al. (2013) Differential control of opioid antinociception to thermal stimuli in a knock-in mouse expressing regulator of G-protein signaling-insensitive Gαo protein. J Neurosci 33:4369-77
Kaur, Kuljeet; Parra, Sergio; Chen, Rong et al. (2012) Gαi2 signaling: friend or foe in cardiac injury and heart failure? Naunyn Schmiedebergs Arch Pharmacol 385:443-53
Waterson, Rachael E; Thompson, Corbin G; Mabe, Nathaniel W et al. (2011) Gα(i2)-mediated protection from ischaemic injury is modulated by endogenous RGS proteins in the mouse heart. Cardiovasc Res 91:45-52
Sjogren, Benita; Neubig, Richard R (2010) Thinking outside of the "RGS box": new approaches to therapeutic targeting of regulators of G protein signaling. Mol Pharmacol 78:550-7
Signarvic, Rachel S; Cierniewska, Aleksandra; Stalker, Timothy J et al. (2010) RGS/Gi2alpha interactions modulate platelet accumulation and thrombus formation at sites of vascular injury. Blood 116:6092-100
Blazer, Levi L; Roman, David L; Muxlow, Molly R et al. (2010) Use of flow cytometric methods to quantify protein-protein interactions. Curr Protoc Cytom Chapter 13:Unit 13.11.1-15
Evelyn, Chris R; Bell, Jessica L; Ryu, Jenny G et al. (2010) Design, synthesis and prostate cancer cell-based studies of analogs of the Rho/MKL1 transcriptional pathway inhibitor, CCG-1423. Bioorg Med Chem Lett 20:665-72

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