title: Arginine vasopressin enhances cell survival via a G protein-coupled receptor kinase 2/β-arrestin1/extracellular-regulated kinase 1/2-dependent pathway in H9c2 cells.
abstract: Circulating levels of arginine vasopressin (AVP) are elevated during hypovolemia and during cardiac stress. AVP activates arginine vasopressin type 1A (V(1A))/Gα(q)-coupled receptors in the heart and vasculature and V(2)/Gα(s)-coupled receptors in the kidney. However, little is known regarding the signaling pathways that influence the effects of V(1A) receptor (V(1A)R) activation during cellular injury. Using hypoxia-reoxygenation (H/R) as a cell injury model, we evaluated cell survival and caspase 3/7 activity in H9c2 myoblasts after treatment with AVP. Pretreatment of H9c2 cells with AVP significantly reduced H/R-induced cell death and caspase 3/7 activity, effects that were blocked via both selective V(1A)R inhibition and mitogen-activated protein kinase (MEK1/2) inhibition. AVP increased extracellular-regulated kinase 1/2 (ERK1/2) phosphorylation in a concentration-dependent manner that was sensitive to MEK1/2 inhibition and V(1A)R inhibition, but not V(1B)R or V(2)R inhibition. Discrete elements of the V(1A)/Gα(q)-protein kinase C (PKC) and V(1A)/G protein-coupled receptor kinase (GRK)/β-arrestin signaling cascades were inhibited to dissect the pathways responsible for the protective effects of V(1A)R signaling: Gα(q) (overexpression of Gq-I-ires-green fluorescent protein), PKC (administration of Ro 31-82425; 2-[8-(aminomethyl)-6,7,8,9-tetrahydropyrido[1,2-a]indol-3-yl]-3-(1-methyl-1H-indol-3-yl)maleimide, HCl, bisindolylmaleimide X, HCl), GRK2 [C-terminal GRK2 peptide overexpression and small interfering RNA (siRNA) knockdown], GRK5 (siRNA knockdown), and β-arrestin1 (siRNA knockdown). These studies demonstrated that both Gα(q)/PKC- and GRK2/β-arrestin1-dependent V(1A)R signaling were capable of inducing ERK1/2 phosphorylation in response to AVP stimulation. However, AVP-mediated protection against H/R was elicited only via GRK2- and β-arrestin1-dependent signaling. These results suggest that activation of the V(1A)R in H9c2 cells mediates protective signaling via a GRK2/β-arrestin1/ERK1/2-dependent mechanism that leads to decreased caspase 3/7 activity and enhanced survival under conditions of ischemic stress.
authors.affiliation: Cardiovascular Research Center, Temple University School of Medicine, Philadelphia, PA, USA. weizhong.zhu@temple.edu
authors.forename: Weizhong
authors.initials: W
authors.lastname: Zhu
authors.forename: Douglas G
authors.initials: DG
authors.lastname: Tilley
authors.forename: Valerie D
authors.initials: VD
authors.lastname: Myers
authors.forename: Ryan C
authors.initials: RC
authors.lastname: Coleman
authors.forename: Arthur M
authors.initials: AM
authors.lastname: Feldman
mesh_terms: D000818:Animals; D001127:Arginine Vasopressin / Q000494:pharmacology*; D019390:Arrestins / Q000378:metabolism*; D053148:Caspase 3 / Q000378:metabolism; D053179:Caspase 7 / Q000378:metabolism; D016923:Cell Death / Q000187:drug effects; D002470:Cell Survival / Q000187:drug effects*; D054769:G-Protein-Coupled Receptor Kinase 2 / Q000378:metabolism*; D054774:G-Protein-Coupled Receptor Kinase 5 / Q000378:metabolism; D020935:MAP Kinase Signaling System / Q000187:drug effects*; D020928:Mitogen-Activated Protein Kinases / Q000378:metabolism; D032446:Myoblasts / Q000166:cytology* / Q000187:drug effects* / Q000378:metabolism; D010766:Phosphorylation; D011493:Protein Kinase C / Q000378:metabolism; D051381:Rats; D017483:Receptors, Vasopressin / Q000378:metabolism; D000071557:beta-Arrestins
chemical_list: D019390:Arrestins; D017483:Receptors, Vasopressin; C582098:V1a vasopressin receptor, rat; D000071557:beta-Arrestins; D001127:Arginine Vasopressin; D011493:Protein Kinase C; C496569:Grk2 protein, rat; D054769:G-Protein-Coupled Receptor Kinase 2; D054774:G-Protein-Coupled Receptor Kinase 5; C517897:Grk5 protein, rat; D020928:Mitogen-Activated Protein Kinases; C505410:Casp3 protein, rat; D053148:Caspase 3; D053179:Caspase 7