HMG-CoA reductase inhibitor enhances inducible nitric oxide synthase expression in rat vascular smooth muscle cells; involvement of the Rho/Rho kinase pathway.
ABSTRACT Little is known about the mechanism by which HMG-CoA reductase inhibitors affect inducible nitric oxide synthase (iNOS) expression. We investigated the effect of HMG-CoA reductase inhibitor cerivastatin on iNOS expression in cultured rat vascular smooth muscle cells (VSMCs). Quiescent VSMCs were incubated with or without various concentrations of drugs as follows: cerivastatin, C3 exoenzyme or Y-27632. Then, pretreated VSMCs were stimulated by a vehicle or interleukin (IL)-1beta (10 ng/ml). Treatment of VSMCs with cerivastatin (10(-7)-10(-5) mol/l), which inhibits isoprenylation of Rho and other small G proteins, significantly increased nitrite/nitrate (NOx) production and upregulated the expression of iNOS mRNA in IL-1beta-stimulated VSMCs. This effect of cerivastatin was abolished by cotreatment with mevalonate (2x10(-4) mol/l) or geranylgeranyl-pyrophosphate (GGPP) (10(-5) mol/l), but not by farnesyl-pyrophosphate (10(-5) mol/l). Furthermore, C3 exoenzyme (50 microg/ml), an inactivator of Rho protein, and Rho kinase inhibitor Y-27632 (10(-5) mol/l) also enhanced NOx production and the expression of iNOS mRNA in IL-1beta-stimulated VSMCs. Immunocytochemical study revealed that cerivastatin, C3 exoenzyme and Y-27632 did not affect the nuclear translocation of nuclear factor-kappaB in IL-1beta-stimulated VSMCs. Our study suggests that cerivastatin stimulates iNOS expression in IL-1beta treated VSMCs by its inhibitory effect on Rho/Rho kinase pathway. In addition, this effect of cerivastatin, by enhancing iNOS expression, may contribute to the prevention of restenosis after percutaneous coronary intervention and protect against atherothrombosis.
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ABSTRACT: Smooth muscle cell (SMC) migration contributes to vascular remodeling. Nitric oxide (NO) produced via endothelial NO synthase (eNOS) inhibits SMC migration. This study analyzes signal transduction mechanisms of SMC migration targeted by NO. SMCs were cultured from human saphenous veins, and cell migration was studied using Boyden chambers. PDGF-BB (0.1 to 10 ng/ml) stimulated SMC migration in a concentration-dependent manner, which was inhibited by adenoviral-mediated overexpression of eNOS and by the NO donor diethylentriamine NONOate (DETANO, 10 to 10 mol/L). NO release was enhanced in eNOS-transduced SMCs, and L-NAME blunted the effect of eNOS overexpression on migration. PDGF-BB (10 ng/ml) activated Rho A, which was inhibited by the overexpression of eNOS by DETANO and by 8 bromo-cGMP. The inhibitory effect of DETANO on Rho A activity was prevented by the cGMP-dependant kinase inhibitor. Furthermore, inhibition of Rho A by C3 exoenzyme and inhibition of ROCK by Y-27632 diminished cell migration stimulated by PDGF-BB. Finally, in the cells overexpressing constitutively active ROCK mutant (CAT), DETANO failed to prevent PDGF-BB-induced SMC migration. In conclusion, NO inhibits human SMC migration via blockade of the Rho A pathway.Journal of cardiovascular pharmacology 11/2008; 52(4):369-74. · 2.83 Impact Factor
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ABSTRACT: The small GTP-binding protein, RhoA, and its downstream effector protein, rho-kinase, have been implicated in the pathogenesis of a number of cardiovascular diseases. The activation of rho-kinase is involved in the development of increased vascular tone, endothelial dysfunction, inflammation, and restenosis; and that the inhibition of rho-kinase has been shown to have a beneficial effect in a variety of cardiovascular disorders. It is our hypothesis that rho-kinase inhibitors promote vasodilation independent of the mechanism that increases vasoconstrictor tone and moreover, the RhoA/rho-kinase pathway has a role in the regulation of smooth muscle tone under physiological conditions. The objective of this review is to improve our current understanding of the role of RhoA/rho-kinase pathway in the regulation of vasoconstrictor tone and the use of rho-kinase inhibitors in the treatment of cardiovascular disorders with an emphasis on pulmonary hypertension.Current Drug Discovery Technologies 04/2009; 6(1):59-71.
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ABSTRACT: Vascular aging is characterized by vascular cell senescence, increased oxidative stress, and endothelial and inducible nitric oxide (NO) synthase (eNOS/iNOS) imbalance, which reduces NO bioavailability and causes endothelial dysfunction. We investigated whether long-term administration of atorvastatin affects endothelial dysfunction and the underlying mechanisms. Aortas from young (2months), middle-aged (12months), and old (20months) control rats that had received a routine diet and from old rats (20months) that had received a diet mixed with atorvastatin (5mg/kg/day) for 8 months were investigated. Senescent phenotype, vascular reactivity, superoxide dismutase (SOD), malonyldialdehyde (MDA), total NO, calcium-dependent and -independent NOS activity, and eNOS, iNOS, and sirtuin-1 (SIRT1) expression at the transcriptional and translational levels were assessed in rat aortas. Comparisons between young, middle, and old control rats showed that the senescent phenotype was enhanced in intima and media (p<0.01), and that MDA, calcium-independent NOS activity, and iNOS increased with age (p<0.01), whereas endothelium-dependent relaxation, SOD, NO, calcium-dependent NOS activity, eNOS, the eNOS/iNOS ratio, and SIRT1 declined with age (p<0.01). Compared with old controls, long-term administration of atorvastatin to old rats inhibited the senescent phenotype (p<0.05), improved endothelium-dependent relaxation (p<0.05 or 0.01), decreased MDA (p<0.01), increased SOD, NO, eNOS, and SIRT1 expression (p<0.01), and inhibited iNOS expression (not detectable) in aged rat aortas. The results indicate that the long-term administration of atorvastatin improves age-related endothelial dysfunction in aged rats via inhibition of the senescent phenotype, amelioration of oxidative stress, and normalization of eNOS/iNOS imbalance.Experimental gerontology 01/2014; · 3.34 Impact Factor