Department of Immunobiology, Jinan University, Guangzhou 510632, China.
Department of Immunobiology, Jinan University, Guangzhou 510632, China; Key Laboratory of Functional Protein Research of Guangdong Higher Education Institutes, Jinan University, Guangzhou 510632, China.
Microvasc Res. 2014 Jan;91:58-65. doi: 10.1016/j.mvr.2013.10.007. Epub 2013 Nov 4.
Human endothelial nitric oxide synthase (eNOS) activity is important for maintaining blood pressure homeostasis and vascular integrity through nitric oxide (NO).The in vitro study aimed at investigating a role of p38α signaling in modulating NO production in human umbilical vein endothelial cell-12 (HUVEC-12). Consistent with the stimulation of lipopolysaccharide (LPS) or tumor necrosis factor (TNF)-α, the over-expression of p38α markedly down-regulated the eNOS promoter activity in HUVEC-12, which could be reversed by its negative mutant p38α (AF) or p38-specific inhibitor SB203580. Compared to the stimulation of LPS or TNF-α, p38α-targeting siRNA decreased the expressions of phosphorylated and non-phosphorylated p38α, and increased the promoter activity, an eNOS mRNA level and a phosphorylated eNOS protein expression with the enhancement of NO, which could be abrogated by the scrambled siRNA. The in situ eNOS protein expression in the cells treated by p38α-targeting siRNA was also higher than that of the control, following the corresponding attenuation of a p38 level, and mainly localized in the inner membrane and cytoplasm. These results indicate that the p38α subtype may be a potential target to down-regulate the eNOS activity and NO production in human endothelial cells.
人内皮型一氧化氮合酶（eNOS）的活性对于通过一氧化氮（NO）维持血压稳态和血管完整性非常重要。体外研究旨在探讨 p38α 信号在调节人脐静脉内皮细胞-12（HUVEC-12）中 NO 产生中的作用。与脂多糖（LPS）或肿瘤坏死因子（TNF）-α的刺激一致，p38α 的过表达显著下调了 HUVEC-12 中的 eNOS 启动子活性，这可以通过其负突变体 p38α（AF）或 p38 特异性抑制剂 SB203580 逆转。与 LPS 或 TNF-α 的刺激相比，p38α 靶向 siRNA 降低了磷酸化和非磷酸化 p38α 的表达，并增加了启动子活性、eNOS mRNA 水平和磷酸化 eNOS 蛋白表达，同时增强了 NO 的产生，这可以通过 scrambled siRNA 消除。用 p38α 靶向 siRNA 处理的细胞中的原位 eNOS 蛋白表达也高于对照，相应地降低了 p38 水平，并且主要定位于内膜和细胞质中。这些结果表明，p38α 亚型可能是下调人内皮细胞中 eNOS 活性和 NO 产生的潜在靶标。
