Vascular Biology Unit, X720, 650 Albany St, Boston, MA 02118, USA.
Circ Res. 2010 Oct 15;107(8):975-83. doi: 10.1161/CIRCRESAHA.110.221242. Epub 2010 Aug 19.
Vascular smooth muscle cell (SMC) migration is an important pathological process in several vascular occlusive diseases, including atherosclerosis and restenosis, both of which are accelerated by diabetes mellitus.
To determine the mechanisms of abnormal vascular SMC migration in type 2 diabetes, the obese Zucker rat (ZO), a model of obesity and insulin resistance, was studied.
In culture, ZO aortic SMCs showed a significant increase in Nox4 mRNA and protein levels compared with the control lean Zucker rat (ZL). The sarco-/endoplasmic reticulum Ca(2+) ATPase (SERCA) nitrotyrosine-294,295 and cysteine-674 (C674)-SO(3)H were increased in ZO SMCs, indicating oxidant stress. Unlike ZL SMC, nitric oxide (NO) failed to inhibit serum-induced SMC migration in ZO. Transfection of Nox4 small interference RNA or overexpression of SERCA2b wild type, but not C674S mutant SERCA, restored the response to NO. Knockdown of Nox4 also decreased SERCA oxidation in ZO SMCs. In addition, transforming growth factor-β1 via Smad2 was necessary and sufficient to upregulate Nox4, oxidize SERCA, and block the antimigratory action of NO in ZO SMCs. Corresponding to the results in cultured SMCs, immunohistochemistry confirmed that Nox4 and SERCA C674-SO(3)H were significantly increased in ZO aorta. After common carotid artery injury, knockdown of Nox4 by adenoviral Nox4 short hairpin RNA decreased Nox4 and SERCA C674-SO(3)H staining and significantly decreased injury-induced neointima.
These studies indicate that the upregulation of Nox4 by transforming growth factor-β1 in ZO SMCs is responsible for the impaired response to NO by a mechanism involving the oxidation of SERCA C674. Knockdown of Nox4 inhibits oxidation of SERCA, as well as neointima formation, after ZO common carotid artery injury.
血管平滑肌细胞（SMC）迁移是几种血管闭塞性疾病的重要病理过程，包括动脉粥样硬化和再狭窄，这两种疾病都被糖尿病加速。
为了确定 2 型糖尿病中血管平滑肌细胞迁移异常的机制，研究了肥胖型 Zucker 大鼠（ZO），一种肥胖和胰岛素抵抗的模型。
在培养中，ZO 主动脉 SMC 的 Nox4 mRNA 和蛋白水平明显高于对照 lean Zucker 大鼠（ZL）。ZO SMC 的肌浆网/内质网 Ca2+-ATP 酶（SERCA）硝基酪氨酸-294、295 和半胱氨酸-674（C674）-SO3H 增加，表明存在氧化应激。与 ZL SMC 不同的是，NO 未能抑制 ZO 中的血清诱导的 SMC 迁移。Nox4 小干扰 RNA 的转染或 SERCA2b 野生型的过表达，但不是 C674S 突变型 SERCA 的过表达，恢复了对 NO 的反应。Nox4 的敲低也降低了 ZO SMC 中的 SERCA 氧化。此外，转化生长因子-β1 通过 Smad2 上调 Nox4、氧化 SERCA，并阻断 ZO SMC 中 NO 的抗迁移作用。与培养的 SMC 结果相对应，免疫组织化学证实 ZO 主动脉中 Nox4 和 SERCA C674-SO3H 明显增加。在颈总动脉损伤后，腺病毒 Nox4 短发夹 RNA 敲低 Nox4 降低了 Nox4 和 SERCA C674-SO3H 染色，并显著减少了损伤诱导的新生内膜。
这些研究表明，转化生长因子-β1 在 ZO SMC 中上调 Nox4 是导致 NO 反应受损的原因，其机制涉及 SERCA C674 的氧化。在 ZO 颈总动脉损伤后，Nox4 的敲低抑制了 SERCA 的氧化以及新生内膜的形成。
