title: A beta1-adrenergic receptor CaM kinase II-dependent pathway mediates cardiac myocyte fetal gene induction.
abstract: Beta-adrenergic signaling plays an important role in the natural history of dilated cardiomyopathies. Chronic activation of beta-adrenergic receptors (beta1-AR and beta2-AR) during periods of cardiac stress ultimately harms the failing heart by mechanisms that include alterations in gene expression. Here, we show that stimulation of beta-ARs with isoproterenol in neonate rat ventricular myocytes causes a "fetal" response in the relative activities of the human cardiac fetal and/or adult gene promoters that includes repression of the human and rat alpha-myosin heavy chain (alpha-MyHC) promoters with simultaneous activation of the human atrial natriuretic peptide (ANP) and rat beta-MyHC promoters. We also show that the promoter changes correlate with changes in endogenous gene expression as measured by mRNA expression. Furthermore, we show that these changes are specifically mediated by the beta1-AR, but not the beta2-AR, and are independent of alpha1-AR stimulation. We also demonstrate that the fetal gene response is independent of cAMP and protein kinase A, whereas inhibition of Ca2+/calmodulin-dependent protein kinase (CaMK) pathway blocks isoproterenol-mediated fetal gene program induction. Finally, we show that induction of the fetal program is dependent on activation of the L-type Ca2+ channel. We conclude that in neonatal rat cardiac myocytes, agonist-occupied beta1-AR mobilizes Ca2+ stores to activate fetal gene induction through cAMP independent pathways that involve CaMK.
authors.affiliation: University of Colorado Cardiovascular Institute, Campus Box B130, UCHSC, Denver, CO 80262, USA.
authors.forename: Carmen C
authors.initials: CC
authors.lastname: Sucharov
authors.forename: Peter D
authors.initials: PD
authors.lastname: Mariner
authors.forename: Karin R
authors.initials: KR
authors.lastname: Nunley
authors.forename: Carlin
authors.initials: C
authors.lastname: Long
authors.forename: Leslie
authors.initials: L
authors.lastname: Leinwand
authors.forename: Michael R
authors.initials: MR
authors.lastname: Bristow
mesh_terms: D000199:Actins / Q000235:genetics / Q000378:metabolism; D000318:Adrenergic beta-Agonists / Q000494:pharmacology; D000818:Animals; D009320:Atrial Natriuretic Factor / Q000235:genetics / Q000378:metabolism; D020746:Calcium Channels, L-Type / Q000502:physiology; D054732:Calcium-Calmodulin-Dependent Protein Kinase Type 2; D017871:Calcium-Calmodulin-Dependent Protein Kinases / Q000502:physiology*; D002478:Cells, Cultured; D000242:Cyclic AMP / Q000502:physiology; D005786:Gene Expression Regulation / Q000187:drug effects / Q000502:physiology*; D006801:Humans; D007545:Isoproterenol / Q000494:pharmacology; D032383:Myocytes, Cardiac / Q000378:metabolism*; D018995:Myosin Heavy Chains / Q000235:genetics / Q000378:metabolism; D020097:Natriuretic Peptide, Brain / Q000235:genetics / Q000378:metabolism; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D051381:Rats; D018342:Receptors, Adrenergic, beta-1 / Q000502:physiology*; D015398:Signal Transduction / Q000502:physiology*; D015533:Transcriptional Activation
chemical_list: D000199:Actins; D000318:Adrenergic beta-Agonists; D020746:Calcium Channels, L-Type; D012333:RNA, Messenger; D018342:Receptors, Adrenergic, beta-1; D020097:Natriuretic Peptide, Brain; D009320:Atrial Natriuretic Factor; D000242:Cyclic AMP; D054732:Calcium-Calmodulin-Dependent Protein Kinase Type 2; D017871:Calcium-Calmodulin-Dependent Protein Kinases; D018995:Myosin Heavy Chains; D007545:Isoproterenol