A cardiac pathway of cyclic GMP-independent signaling of guanylyl cyclase A, the receptor for atrial natriuretic peptide.
Proc Natl Acad Sci U S A
; 108(45): 18500-5, 2011 Nov 08.
Article
em En
| MEDLINE
| ID: mdl-22027011
ABSTRACT
Cardiac atrial natriuretic peptide (ANP) regulates arterial blood pressure, moderates cardiomyocyte growth, and stimulates angiogenesis and metabolism. ANP binds to the transmembrane guanylyl cyclase (GC) receptor, GC-A, to exert its diverse functions. This process involves a cGMP-dependent signaling pathway preventing pathological [Ca(2+)](i) increases in myocytes. In chronic cardiac hypertrophy, however, ANP levels are markedly increased and GC-A/cGMP responses to ANP are blunted due to receptor desensitization. Here we show that, in this situation, ANP binding to GC-A stimulates a unique cGMP-independent signaling pathway in cardiac myocytes, resulting in pathologically elevated intracellular Ca(2+) levels. This pathway involves the activation of Ca(2+)-permeable transient receptor potential canonical 3/6 (TRPC3/C6) cation channels by GC-A, which forms a stable complex with TRPC3/C6 channels. Our results indicate that the resulting cation influx activates voltage-dependent L-type Ca(2+) channels and ultimately increases myocyte Ca(2)(+)(i) levels. These observations reveal a dual role of the ANP/GC-A-signaling pathway in the regulation of cardiac myocyte Ca(2+)(i) homeostasis. Under physiological conditions, activation of a cGMP-dependent pathway moderates the Ca(2+)(i)-enhancing action of hypertrophic factors such as angiotensin II. By contrast, a cGMP-independent pathway predominates under pathophysiological conditions when GC-A is desensitized by high ANP levels. The concomitant rise in [Ca(2+)](i) might increase the propensity to cardiac hypertrophy and arrhythmias.
Texto completo:
1
Base de dados:
MEDLINE
Assunto principal:
Transdução de Sinais
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Fator Natriurético Atrial
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Receptores do Fator Natriurético Atrial
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GMP Cíclico
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Guanilato Ciclase
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Miocárdio
Limite:
Animals
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Humans
Idioma:
En
Ano de publicação:
2011
Tipo de documento:
Article