کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
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2550381 | 1560565 | 2016 | 9 صفحه PDF | دانلود رایگان |
![عکس صفحه اول مقاله: Nox4 contributes to the hypoxia-mediated regulation of actin cytoskeleton in cerebrovascular smooth muscle Nox4 contributes to the hypoxia-mediated regulation of actin cytoskeleton in cerebrovascular smooth muscle](/preview/png/2550381.png)
Ischemia/reperfusion and the resulting oxidative/nitrative stress impair cerebral myogenic tone via actin depolymerization. While it is known that NADPH oxidase (Nox) family is a major source of vascular oxidative stress; the extent and mechanisms by which Nox activation contributes to actin depolymerization, and equally important, the relative role of Nox isoforms in this response is not clear. Aim: To determine the role of Nox4 in hypoxia-mediated actin depolymerization and myogenic-tone impairment in cerebral vascular smooth muscle. Main methods: Control and Nox4 deficient (siRNA knock-down) human brain vascular smooth muscle cells (HBVSMC) were exposed to 30-min hypoxia/45-min reoxygenation. Nox2, Nox4, inducible and neuronal nitric oxide synthase (iNOS and nNOS) and nitrotyrosine levels as well as F:G actin were determined. Myogenic-tone was measured using pressurized arteriography in middle cerebral artery isolated from rats subjected to sham, 30-min ischemia/45-min reperfusion or ex-vivo oxygen glucose deprivation in the presence and absence of Nox inhibitors. Results: Nox4 and iNOS expression were significantly upregulated following hypoxia or ischemia/reperfusion. Hypoxia augmented nitrotyrosine levels while reducing F actin. These effects were nullified by inhibiting nitration with epicatechin or pharmacological or molecular inhibition of Nox4. Ischemia/reperfusion impaired myogenic-tone, which was restored by the selective inhibition of Nox4. Conclusion: Nox4 activation in VSMCs contributes to actin depolymerization after hypoxia, which could be the underlying mechanism for myogenic-tone impairment following ischemia/reperfusion.
Journal: Life Sciences - Volume 163, 15 October 2016, Pages 46–54