TY - JOUR
T1 - Reduction of sympathetic activity via adrenal-targeted GRK2 gene deletion attenuates heart failure progression and improves cardiac function after myocardial infarction
AU - Lymperopoulos, Anastasios
AU - Rengo, Giuseppe
AU - Gao, Erhe
AU - Ebert, Steven N.
AU - Dorn, Gerald W.
AU - Koch, Walter J.
PY - 2010/5/21
Y1 - 2010/5/21
N2 - Chronic heart failure (HF) is characterized by sympathetic overactivity and enhanced circulating catecholamines (CAs), which significantly increase HF morbidity and mortality. We recently reported that adrenal G protein-coupled receptor kinase 2 (GRK2) is up-regulated in chronic HF, leading to enhanced CA release via desensitization/down-regulation of the chromaffin cell α2-adrenergic receptors that normally inhibit CA secretion. We also showed that adrenal GRK2 inhibition decreases circulating CAs and improves cardiac inotropic reserve and function. Herein, we hypothesized that adrenal-targeted GRK2 gene deletion before the onset of HF might be beneficial by reducing sympathetic activation. To specifically delete GRK2 in the chromaffin cells of the adrenal gland, we crossed PNMTCre mice, expressing Cre recombinase under the chromaffin cell-specific phenylethanolamine N-methyltransferase (PNMT) gene promoter, with floxedGRK2 mice. After confirming a significant (∼50%) reduction of adrenal GRK2 mRNA and protein levels, the PNMT-driven GRK2 knockout (KO) offspring underwent myocardial infarction (MI) to induce HF. At 4 weeks post-MI, plasma levels of both norepinephrine and epinephrine were reduced in PNMT-driven GRK2 KO, compared with control mice, suggesting markedly reduced post-MI sympathetic activation. This translated in PNMT-driven GRK2 KO mice into improved cardiac function and dimensions as well as amelioration of abnormal cardiac β-adrenergic receptor signaling at 4 weeks post-MI. Thus, adrenal-targeted GRK2 gene KO decreases circulating CAs, leading to improved cardiac function and β-adrenergic reserve in post-MI HF. GRK2 inhibition in the adrenal gland might represent a novel sympatholytic strategy that can aid in blocking HF progression.
AB - Chronic heart failure (HF) is characterized by sympathetic overactivity and enhanced circulating catecholamines (CAs), which significantly increase HF morbidity and mortality. We recently reported that adrenal G protein-coupled receptor kinase 2 (GRK2) is up-regulated in chronic HF, leading to enhanced CA release via desensitization/down-regulation of the chromaffin cell α2-adrenergic receptors that normally inhibit CA secretion. We also showed that adrenal GRK2 inhibition decreases circulating CAs and improves cardiac inotropic reserve and function. Herein, we hypothesized that adrenal-targeted GRK2 gene deletion before the onset of HF might be beneficial by reducing sympathetic activation. To specifically delete GRK2 in the chromaffin cells of the adrenal gland, we crossed PNMTCre mice, expressing Cre recombinase under the chromaffin cell-specific phenylethanolamine N-methyltransferase (PNMT) gene promoter, with floxedGRK2 mice. After confirming a significant (∼50%) reduction of adrenal GRK2 mRNA and protein levels, the PNMT-driven GRK2 knockout (KO) offspring underwent myocardial infarction (MI) to induce HF. At 4 weeks post-MI, plasma levels of both norepinephrine and epinephrine were reduced in PNMT-driven GRK2 KO, compared with control mice, suggesting markedly reduced post-MI sympathetic activation. This translated in PNMT-driven GRK2 KO mice into improved cardiac function and dimensions as well as amelioration of abnormal cardiac β-adrenergic receptor signaling at 4 weeks post-MI. Thus, adrenal-targeted GRK2 gene KO decreases circulating CAs, leading to improved cardiac function and β-adrenergic reserve in post-MI HF. GRK2 inhibition in the adrenal gland might represent a novel sympatholytic strategy that can aid in blocking HF progression.
UR - http://www.scopus.com/inward/record.url?scp=77952368252&partnerID=8YFLogxK
U2 - 10.1074/jbc.M109.077859
DO - 10.1074/jbc.M109.077859
M3 - Article
C2 - 20351116
AN - SCOPUS:77952368252
SN - 0021-9258
VL - 285
SP - 16378
EP - 16386
JO - Journal of Biological Chemistry
JF - Journal of Biological Chemistry
IS - 21
ER -