Differential regulation of the inducible nitric oxide synthase gene by estrogen receptors 1 and 2.
Differential regulation of the inducible nitric oxide synthase gene by estrogen receptors 1 and 2.
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DOI：
10.1677/joe-07-0292
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发表时间：
2008-11
期刊：
影响因子：
--
通讯作者：
Mendelsohn ME
中科院分区：
文献类型：
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作者：
Tsutsumi S;Zhang X;Takata K;Takahashi K;Karas RH;Kurachi H;Mendelsohn ME
雌激素通过两种雌激素受体 ERα 和 ERβ 介导，对心血管组织具有快速和长期的直接影响。先前的研究发现雌激素调节血管平滑肌细胞（VSMC）中诱导型一氧化氮合酶（iNOS）的表达。 ERβ敲除小鼠由于iNOS表达失调而具有血管功能障碍，并且这些小鼠患有高血压（Zhu等人，Science 2002；295：505-508）。在这里，我们报告了研究 ERα 和 ERβ 对 iNOS 基因表达的差异调节。免疫印迹和 RT-PCR 研究表明，不同的 VSMC 系表达不同水平的 ERα 和 ERβ 蛋白和 mRNA。研究了来自不同血管床的VSMC，包括表达ERα的主动脉VSMC和表达ERβ的桡动脉VSMC。 E2 抑制主动脉 VSMC 中 NO 的产生和 iNOS 蛋白的表达。人类 iNOS 启动子报告基因研究揭示了 E2 在主动脉 VSMC 中抑制 iNOS 报告基因活性，并在桡动脉 VSMC 中刺激 iNOS 报告基因活性。在缺乏内源 ER 的 COS-7 细胞的异源表达研究中，在 ERα 存在的情况下，COS-7 细胞的 E2 处理不会改变 iNOS 报告基因活性，而在 ERβ 存在的情况下报告基因活性增加 2.3 倍。使用选择性雌激素受体调节剂雷洛昔芬在 COS-7 细胞中进行的类似实验表明，雷洛昔芬导致 ERα 共表达时 iNOS 报告活性降低，而 ERβ 共表达时 iNOS 报告活性增加。表达 ERβ 但不表达 ERα 的大鼠 VSMC 也显示出 E2 处理后 iNOS 报告基因活性增加，但当将 ERα 引入细胞时，这种作用消失。综上所述，这些数据支持 VSMC 中 hiNOS 转录受 ERβ 正向调节，并受 ERα 负向调节，支持这两种雌激素受体对血管平滑肌细胞中生理相关基因的差异作用。
Estrogen has both rapid and longer-term direct effects on cardiovascular tissues mediated by the two estrogen receptors, ERα and ERβ. Previous work identified that estrogen regulates the expression of inducible nitric oxide synthase (iNOS) in vascular smooth muscle cells (VSMC). ERβ knockout mice have vascular dysfunction due to dysregulation of iNOS expression and these mice are hypertensive (Zhu et al, Science 2002;295:505-508). Here we report studies to examine the differential regulation of iNOS gene expression by ERα and ERβ. Immunoblotting and RT-PCR studies revealed that different VSMC lines expressed different levels of ERα and ERβ protein and mRNA. VSMC from different vascular beds were studied, including aortic VSMC expressing ERα and radial VSMC expressing ERβ. E2 inhibited NO production and iNOS protein expression in aortic VSMC. Human iNOS promoter reporter studies revealed suppression of iNOS reporter activity by E2 in aortic VSMC, and stimulation of iNOS reporter activity by E2 in radial arterial VSMC. In heterologous expression studies of COS-7 cells lacking endogenous ER, E2 treatment of COS-7 cells did not alter iNOS reporter activity in the presence of ERα, while reporter activity increased 2.3 fold in the presence of ERβ. Similar experiments in COS-7 cells using the selective estrogen receptor modulator raloxifene showed that raloxifene caused a reduction in iNOS reporter activity with ERα co-expression, and an increase with ERβ co-expression. Rat VSMC expressing ERβ but not ERα also showed increased iNOS reporter activity with E2 treatment, an effect lost when ERα was introduced into the cells. Taken together, these data support that hiNOS transcription is positively regulated by ERβ and negatively regulated by ERα in VSMC, supporting differential actions of these two estrogen receptors on a physiologically relevant gene in vascular smooth muscle cells.