Mechanical stretch induced interleukin-18 (IL-18) expression through Angiotensin subtype 1 receptor (AT1R) and endothelin-1 in cardiomyocytes.
Prep Biochem Biotechnol
; 38(2): 201-12, 2008.
Article
em En
| MEDLINE
| ID: mdl-18320471
ABSTRACT
Interleukin-18 (IL-18) is a proinflammatory cytokine with multiple biological functions. We and others have demonstrated that an increased level of circulating IL-18 is one of the risk factors for cardiovascular diseases. Endothelin-1 (ET-1) has been reported to be a potent hypertrophy-promoting factor through RhoA and Rho-Kinase. Mechanical stretch induces a hypertrophic response, partly through the production of ET-1 through Endothelin A receptor (ETAR). Moreover, it has also been reported that mechanical stretch induces cardiac hypertrophy through Angiotensin subtype 1 receptor (AT1R). However, the mechanism by which the IL-18 gene expression is regulated in cardiomyocytes has not yet been fully understood. This study was designed to elucidate the functional significance of IL-18 gene expression in response to mechanical stretch. Neonatal rat cardiomyocytes cultured on silicone dishes were subjected to stretch. The moderate 20% mechanical stretch resulted in the elevation of IL-18 expression in a time-dependent manner with the maximal level achieved 36 hours after the stretch. Olmesartan, AT1R antagonist inhibited stretch-induced IL-18 expression. ETAR blockade BQ123 inhibited stretch-induced IL-18 expression. However, the Endothelin B receptor (ETBR) receptor blockade BQ788 did not inhibit this reaction. ET-1 induced IL-18 expression, with a peak induction after 4 hours of incubation. These results might suggest that stretch stimulation of cardiomyocytes induced ET-1 and, subsequently, ET-1 up-regulated the IL-18 expression. Furthermore, Fasudil, a Rho-Kinase inhibitor, and Simvastatin, a HMG-CoA reductase inhibitor, led to a significant reduction in mechanical stretch-induced IL-18 expression. These results indicated, for the first time, that IL-18 expression is induced by mechanical stretch in cardiomyocytes via the ETAR, AT1R, and the Rho/Rho-K pathways. The induction of IL-18 from cardiomyocytes by mechanical stress might cause the deterioration of cardiac functions in autocrine and paracrine fashion. The inhibition of IL-18 expression induced by mechanical stress might be one of the mechanisms that account for the beneficial cardiovascular effects of AT1R antagonist, ETAR blockade, Statin, and Rho-Kinase inhibitor.
Texto completo:
1
Base de dados:
MEDLINE
Assunto principal:
Endotelina-1
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Interleucina-18
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Miócitos Cardíacos
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Mecanotransdução Celular
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Receptor Tipo 1 de Angiotensina
Tipo de estudo:
Risk_factors_studies
Limite:
Animals
Idioma:
En
Ano de publicação:
2008
Tipo de documento:
Article