Controlled and cardiac-restricted overexpression of the arginine vasopressin V1A receptor causes reversible left ventricular dysfunction through Gαq-mediated cell signaling.

Abstract

BACKGROUND:

[Arg8]-vasopressin (AVP) activates 3 G-protein-coupled receptors: V1A, V2, and V1B. The AVP-V1A receptor is the primary AVP receptor in the heart; however, its role in cardiac homeostasis is controversial. To better understand AVP-mediated signaling in the heart, we created a transgenic mouse with controlled overexpression of the V1A receptor.

METHODS AND RESULTS:

The V1A receptor transgene was placed under the control of the tetracycline-regulated, cardiac-specific α-myosin heavy chain promoter (V1A-TG). V1A-TG mice had a normal cardiac function phenotype at 10 weeks of age; however, by 24 weeks of age, tetracycline-transactivating factor/V1A-TG mouse hearts had reduced cardiac function, cardiac hypertrophy, and dilatation of the ventricular cavity. Contractile dysfunction was also observed in isolated adult cardiac myocytes. When V1A receptor transgene was induced to be expressed in adult mice (V1A-TG(Ind)), left ventricular dysfunction and dilatation were also seen, albeit at a later time point. Because the V1A receptor mediates cell signaling through Gα(q) protein, we blocked Gα(q) signaling by crossing tetracycline-transactivating factor/V1A mice with transgenic mice that expressed a small inhibitory peptide against Gα(q). Gα(q) blockade abrogated the development of the heart failure phenotype in tetracycline-transactivating factor/V1A-TG mice. The heart failure phenotype could be reversed by administration of doxycycline.

CONCLUSIONS:

Our results demonstrate a role for V1A-mediated signaling in the development of heart failure and support a role for V1A blockade in the treatment of patients with elevated levels of vasopressin.

• Authors: Xue Li, Tung O Chan, Valerie Myers, Ibrul Chowdhury, Xue-Qian Zhang, Jianliang Song, Jin Zhang, Jocelyn Andrel, Hajime Funakoshi, Jeffrey Robbins, Walter J Koch, Terry Hyslop, Joseph Y Cheung, Arthur M Feldman
• Journal: Circulation (Circulation) Vol. 124 Issue 5 Pg. 572-81 (Aug 02 2011) ISSN: 1524-4539 [Electronic] United States
• PMID: 21747049 (Publication Type: Journal Article, Research Support, N.I.H., Extramural)

Chemical References

• Inositol 1,4,5-Trisphosphate Receptors
• Insulin
• Receptors, Vasopressin
• Extracellular Signal-Regulated MAP Kinases
• GTP-Binding Protein alpha Subunits, Gq-G11
• Calcium

Topics

• Action Potentials (physiology)
• Animals
• Calcium (metabolism)
• Cardiomyopathies (genetics, metabolism, physiopathology)
• Extracellular Signal-Regulated MAP Kinases (metabolism)
• Female
• GTP-Binding Protein alpha Subunits, Gq-G11 (genetics, metabolism)
• Gene Expression (drug effects, physiology)
• Heart Failure (genetics, metabolism, physiopathology)
• Humans
• Inositol 1,4,5-Trisphosphate Receptors (metabolism)
• Insulin (metabolism)
• MAP Kinase Signaling System (physiology)
• Male
• Mice
• Mice, Inbred C57BL
• Mice, Transgenic
• Myocardial Contraction (physiology)
• Myocardium (metabolism)
• Phenotype
• Pregnancy
• Prenatal Exposure Delayed Effects (genetics, metabolism, physiopathology)
• Receptors, Vasopressin (genetics)
• Ventricular Dysfunction, Left (genetics, metabolism, physiopathology)