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Sun H.-X.,Nanjing Medical University | Zeng D.-Y.,Cardiac and Cerebrovascular Research Center | Li R.-T.,Nanjing Medical University | Pang R.-P.,Sun Yat Sen University | And 8 more authors.
Hypertension | Year: 2012

Nitric oxide generated by endothelial nitric oxide synthase (eNOS) plays an important role in maintaining cardiovascular homeostasis. Under various pathological conditions, abnormal expression of eNOS contributes to endothelial dysfunction and the development of cardiovascular diseases. A variety of pathological stimuli has been reported to decrease eNOS expression mainly through decreasing eNOS mRNA stability by regulating the binding of several cytosolic proteins to the cis-acting sequences within eNOS mRNA 3′ untranslated regions. However, the detailed mechanisms remain elusive. Because microRNAs inhibit gene expression through binding to the 3′ untranslated regions of their target mRNAs, microRNAs may be the important posttranscriptional modulators of eNOS expression. Here, we provided evidence that eNOS is a direct target of miR-155. Overexpression of miR-155 decreased, whereas inhibition of miR-155 increased, eNOS expression and NO production in human umbilical vein endothelial cells and acetylcholine-induced endothelium-dependent vasorelaxation in human internal mammary arteries. Inflammatory cytokines including tumor necrosis factor-α increased miR-155 expression. Inhibition of miR-155 reversed tumor necrosis factor-α- induced downregulation of eNOS expression and impairment of endothelium- dependent vasorelaxation. Moreover, we observed that simvastatin attenuated tumor necrosis factor-α-induced upregulation of miR-155 and ameliorated the effects of tumor necrosis factor-α on eNOS expression and endothelium-dependent vasodilation. Simvastatin decreased miR-155 expression through interfering mevalonate-geranylgeranyl-pyrophosphate-RhoA signaling pathway. These findings indicated that miR-155 is an essential regulator of eNOS expression and endothelium-dependent vasorelaxation. Inhibition of miR-155 may be a new therapeutic approach to improve endothelial dysfunction during the development of cardiovascular diseases. © 2012 American Heart Association, Inc.

Li S.-Y.,Cardiac and Cerebrovascular Research Center | Wang X.-G.,Sun Yat Sen University | Ma M.-M.,Cardiac and Cerebrovascular Research Center | Liu Y.,Cardiac and Cerebrovascular Research Center | And 7 more authors.
Apoptosis | Year: 2012

Our previous studies showed that ginsenoside-Rd, a purified component from Panax notoginseng, inhibited cell proliferation and reversed basilar artery remodeling. The aim of this study was to investigate whether ginsenoside-Rd influences H 2O 2-induced apoptosis in basilar artery smooth muscle cells (BASMCs). The results showed that ginsenoside-Rd significantly potentiated H 2O 2-induced cell death and cell apoptosis. This resulted in a concentrationdependent reduction of the cell viability. Ginsenoside-Rd further increased cytochrome C release and caspase-9/caspase-3 activations, and reduced the stability of mitochondrial membrane potential (MMP) and the ratio of Bcl-2/Bax. Cyclosporine A, an inhibitor of mitochondrial-permeability transition, inhibited alteration of mitochondrial permeability induced by H 2O 2 and reversed the effect of ginsenoside-Rd on MMP. Our data strongly suggest that ginsenoside-Rd potentiated H 2O 2-induced apoptosis of BASMCs through the mitochondria-dependent pathway. © Springer Science+Business Media, LLC 2011.

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