Role of mitogen-activated protein kinase pathway in reactive oxygen species-mediated endothelin-1-induced β-myosin heavy chain gene expression and cardiomyocyte hypertrophy

Abstract

Endothelin-1 (ET-1) has been found to increase cardiac beta-myosin heavy chain (beta-MyHC) gene expression and induce hypertrophy in cardiomyocytes. ET-1 has been demonstrated to increase intracellular reactive oxygen species (ROS) in cardiomyocytes. The exact molecular mechanism by which ROS regulate ET-1-induced beta-MyHC gene expression and hypertrophy in cardiomyocytes, however, has not yet been fully described. We aim to elucidate the molecular regulatory mechanism of ROS on ET-1-induced beta-MyHC gene expression and hypertrophic signaling in neonatal rat cardiomyocytes. Following stimulation with ET-1, cultured neonatal rat cardiomyocytes were examined for 3H-leucine incorporation and beta-MyHC promoter activities. The effects of antioxidant pretreatment on ET-1-induced cardiac hypertrophy and mitogen-activated protein kinase (MAPKs) phosphorylation were studied to elucidate the redox-sensitive pathway in cardiomyocyte hypertrophy and beta-MyHC gene expression. ET-1 increased 3H-leucine incorporation and beta-MyHC promoter activities, which were blocked by the specific ET(A) receptor antagonist BQ-485. Antioxidants significantly reduced ET-1-induced 3H-leucine incorporation, beta-MyHC gene promoter activities and MAPK (extracellular signal-regulated kinase, p38, and c-Jun NH2 -terminal kinase) phosphorylation. Both PD98059 and SB203580 inhibited ET-1-increased 3H-leucine incorporation and beta-MyHC promoter activities. Co-transfection of the dominant negative mutant of Ras, Raf, and MEK1 decreased the ET-1-induced beta-MyHC promoter activities, suggesting that the Ras-Raf-MAPK pathway is required for ET-1 action. Truncation analysis of the beta-MyHC gene promoter showed that the activator protein-2 (AP-2)/specificity protein-1 (SP-1) binding site(s) were(was) important cis-element(s) in ET-1-induced beta-MyHC gene expression. Moreover, ET-1-induced AP-2 and SP-1 binding activities were also inhibited by antioxidant. These data demonstrate the involvement of ROS in ET-1-induced hypertrophic responses and beta-MyHC expression. ROS mediate ET-1-induced activation of MAPK pathways, which culminates in hypertrophic responses and beta-MyHC expression.

Isoproterenol disperses distribution of NADPH oxidase, MMP-9, and pPKCε in the heart, which are mitigated by endothelin receptor antagonist CPU0213

“…The activity of the redox system is mediated by MAPK which closely links with ET-1 [41] . Upregulation of mRNA of PKCε and pPKCε protein in response to β-stimulation has been previously found [15] and is also confirmed in the present study.…”

Carotid atherosclerosis in elderly hypertensive patients: potential role of endothelin and plasma antioxidant capacity

“…Through excessive oxidative stress and activation of mitogen-activated protein kinase, tyrosine kinase pathways and nuclear factor kB, ET-1 stimulates VSMC proliferation and inflammation, all implicated in the thickening of vascular wall, vascular remodelling and in the development of atherosclerosis and end-organ damage. 8,26 As we have shown recently, there exists an inverse correlation between plasma ET-1 level and FRAP in treated hypertensive subjects. 17 In this study, we developed this observation, and demonstrated that inclusion of FRAP in the multivariate regression model as one of the independent variables changed the relationship between ET-1 and CCA-IMT, and not ET-1, but FRAP, apart from age, SBP and HbA1c level independently inversely influenced CCA-IMT.…”

“…1,4,6 Through the activation of mitogen-activated protein kinase, it stimulates cardiomyocyte hypertrophy. 7,8 Taken together, these findings suggest that ET-1 has a substantial role in the development of atherosclerosis and endorgan damage in patients with hypertension and diabetes. 4,6 The contribution of endogenous ET-1 to cardiovascular regulation and pathogenesis and disease progression has been confirmed by the effects of ET receptor antagonists.…”

“…12,13,16,27 Excessive oxidative stress activates several redox-sensitive signalling pathways resulted in activation of MAP kinase family, tyrosine kinases, transcription factors nuclear factor kB, activator protein-1, vascular cellular adhesion molecule-1 and increase release of proinflammatory cytokines. 8,13,26,28,29 The contribution of ET-1, NAD(P)H oxidase and reactive oxygen species in VSMC proliferation was confirmed by the possibility of blocking this process by pre-incubation of VSMC with ET A receptor antagonist, 13 NAD(P)H oxidase inhibitor 12,16 or with antioxidants; 12,13,16 however, it was documented for extracellular superoxide dismutase, 13 and among the antioxidants included in FRAP for ascorbic acid. 12,16 It was also shown that vitamin C inhibited activation of mitogen-activated protein kinase and VSMC proliferation in cultured rat aortic smooth muscle cells, 26 and in an in vivo experiment it was demonstrated that vitamin C supplementation decreased activation of NADPH oxidase and superoxide anion generation, prevented vascular hypertrophy and increased plasma total antioxidant status and superoxide dismutase in arterial wall in stroke-prone spontaneously hypertensive rats.…”

The influence of ETA and ETB receptor blockers on LPS-induced oxidative stress and NF-κB signaling pathway in heart

“…While Xia et al (2006) indicated that durasentan, an ETA-R inhibitor, downregulates NF-κB expression in heart ventricles. Furthermore, administration of BQ485, ETA-R blocker, reduced ET-1 induced activation of Ras-Raf-MAPK cellular pathway in myocytes inhibiting inflammatory process and cellular damage (Cheng et al 2005).…”