cAMP-mediated beta-adrenergic signaling negatively regulates Gq-coupled receptor-mediated fetal gene response in cardiomyocytes.
The treatment with beta-blockers causes an enhancement of the norepinephrine-induced fetal gene response in cultured cardiomyocytes. Here, we tested whether the activation of cAMP-mediated beta-adrenergic signaling antagonizes alpha(1)-adrenergic receptor (AR)-mediated fetal gene response. To address this question, the fetal gene program, of which atrial natriuretic peptide (ANP) and the beta-isoform of myosin heavy chain are classical members, was induced by phenylephrine (PE), an alpha(1)-AR agonist. In cultured neonatal rat cardiomyocytes, we found that stimulation of beta-ARs with isoproterenol, a beta-AR agonist, inhibited the fetal gene expression induced by PE. Similar results were also observed when cardiomyocytes were treated with forskolin (FSK), a direct activator of adenylyl cyclase, or 8-CPT-6-Phe-cAMP, a selective activator of protein kinase A (PKA). Conversely, the PE-induced fetal gene expression was further upregulated by H89, a selective PKA inhibitor. To evaluate whether these results could be generalized to Gq-mediated signaling and not specifically to alpha(1)-ARs, cardiomyocytes were treated with prostaglandin F(2)alpha, another Gq-coupled receptor agonist, which is able to promote fetal gene expression. This treatment caused an increase of both ANP mRNA and protein levels, which was almost completely abolished by FSK treatment. The capability of beta-adrenergic signaling to regulate the fetal gene expression was also evaluated in vivo conditions by using beta1- and beta2-AR double knockout mice, in which the predominant cardiac beta-AR subtypes are lacking, or by administering isoproterenol (ISO), a beta-AR agonist, at a subpressor dose. A significant increase of the fetal gene expression was found in beta(1)- and beta(2)-AR gene deficient mice. Conversely, we found that ANP, beta-MHC and skACT mRNA levels were significantly decreased in ISO-treated hearts. Collectively, these data indicate that cAMP-mediated beta-adrenergic signaling negatively regulates Gq cascade activation-induced fetal gene expression in cultured cardiomyocytes and that this inhibitory regulation is already operative in the mouse heart under physiological conditions.
Department of Drug Research and Evaluation, Istituto Superiore di Sanità, Rome, Italy.
Mario
M
Patrizio
Valerio
V
Vago
Marco
M
Musumeci
Katia
K
Fecchi
Nadia Maria
NM
Sposi
Elisabetta
E
Mattei
Liviana
L
Catalano
Tonino
T
Stati
Giuseppe
G
Marano
D000262:Adenylyl Cyclases / Q000235:genetics / Q000378:metabolism; D000316:Adrenergic alpha-Agonists / Q000494:pharmacology; D000818:Animals; D009320:Atrial Natriuretic Factor / Q000096:biosynthesis* / Q000235:genetics; D005576:Colforsin / Q000494:pharmacology; D000242:Cyclic AMP / Q000235:genetics / Q000378:metabolism*; D017868:Cyclic AMP-Dependent Protein Kinases / Q000037:antagonists & inhibitors* / Q000235:genetics / Q000378:metabolism; D015237:Dinoprost / Q000494:pharmacology; D020536:Enzyme Activators / Q000494:pharmacology; D005333:Fetus / Q000166:cytology / Q000378:metabolism*; D005786:Gene Expression Regulation / Q000187:drug effects / Q000502:physiology*; D007545:Isoproterenol / Q000494:pharmacology; D007546:Isoquinolines / Q000494:pharmacology; D051379:Mice; D032383:Myocytes, Cardiac / Q000166:cytology / Q000378:metabolism*; D018995:Myosin Heavy Chains / Q000096:biosynthesis / Q000235:genetics; D024501:Nonmuscle Myosin Type IIB / Q000096:biosynthesis / Q000235:genetics; D010656:Phenylephrine / Q000494:pharmacology; D047428:Protein Kinase Inhibitors / Q000494:pharmacology; D012333:RNA, Messenger / Q000096:biosynthesis / Q000235:genetics; D051381:Rats; D017208:Rats, Wistar; D018340:Receptors, Adrenergic, alpha-1 / Q000235:genetics / Q000378:metabolism; D011943:Receptors, Adrenergic, beta / Q000235:genetics / Q000378:metabolism*; D015398:Signal Transduction / Q000187:drug effects / Q000502:physiology*; D013449:Sulfonamides / Q000494:pharmacology
D000316:Adrenergic alpha-Agonists; D020536:Enzyme Activators; D007546:Isoquinolines; D047428:Protein Kinase Inhibitors; D012333:RNA, Messenger; D018340:Receptors, Adrenergic, alpha-1; D011943:Receptors, Adrenergic, beta; D013449:Sulfonamides; D005576:Colforsin; D010656:Phenylephrine; D009320:Atrial Natriuretic Factor; D015237:Dinoprost; D000242:Cyclic AMP; D017868:Cyclic AMP-Dependent Protein Kinases; D024501:Nonmuscle Myosin Type IIB; C103815:nonmuscle myosin type IIB heavy chain; D018995:Myosin Heavy Chains; D000262:Adenylyl Cyclases; D007545:Isoproterenol; C063509:N-(2-(4-bromocinnamylamino)ethyl)-5-isoquinolinesulfonamide