Aldosterone Enhances Ligand-Stimulated Nitric Oxide Production in Endothelial Cells
Aldosterone Enhances Ligand-Stimulated Nitric Oxide Production in Endothelial Cells
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DOI：
10.1291/hypres.31.1811
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发表时间：
2008-09-01
影响因子：
5.4
通讯作者：
Fujita, Toshiro
中科院分区：
文献类型：
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作者：
Mutoh, Akiko;Isshiki, Masashi;Fujita, Toshiro
近年来，醛固酮的慢性和急性作用已被证明直接影响心血管系统。然而，目前尚不清楚醛固酮对血管的急性作用是收缩还是扩张。在这里，为了阐明醛固酮对内皮功能的非基因组效应，我们研究了醛固酮对培养的内皮细胞（EC）中一氧化氮（NO）产生和血管张力的影响。用共聚焦显微镜观察牛主动脉内皮细胞内NO的产生。通过使用膜不可渗透性的酶标仪对培养基中累积的NO进行定量。用Western blotting检测内皮型一氧化氮合酶（eNOS）Ser（1179）的磷酸化。在荧光素-4和呋喃红双重负载的EC中，通过共聚焦显微镜测定细胞内Ca 2+（[Ca 2 +]（i））的变化。在离体器官浴室系统中研究了醛固酮、乙酰胆碱（ACh）和其他信号分子对苯肾上腺素（PE）收缩的Sprague-Dawley大鼠血管张力的影响。醛固酮（1 × 10（-7）mol/L）短期预暴露可增加ATP诱导的内皮细胞NO生成，并增加eNOS在Ser（1179）的磷酸化。这些作用被盐皮质激素受体（MR）拮抗剂依普利酮和磷脂酰肌醇3-激酶（PI 3 K）抑制剂LY 294002阻断。值得注意的是，单独的醛固酮不影响ATP诱导的[Ca 2 +]（i）变化或Ser（1179）磷酸化。同样，醛固酮（1 × 10 - 8 ~ 1 × 10 - 7 mol/L）不影响PE预收缩的大鼠血管张力，但增强ACh诱导的血管舒张，依普利酮或LY 29400可再次逆转该效应。与此相反，硝普钠诱导的血管舒张在内皮剥脱的动脉粥样硬化不受醛固酮。因此，醛固酮通过依普利酮敏感性机制（包括PI 3 K，可协同Ca 2+依赖性eNOS在Ser的磷酸化），急性增强配体介导的内皮NO生成（1179）。（Hypertens Res 2008; 31：1811-1820）
Chronic and acute actions of aldosterone have been shown recently to directly affect the cardiovascular system. However, It is unclear whether the acute effects of aldosterone on vasculature are constrictive or dilatory. Here, to clarify the nongenomic effects of aldosterone on endothelial function, we examined the effects of aldosterone on nitric oxide (NO) production in cultured endothelial cells (ECs) and on vascular tone. The intracellular NO production of bovine aortic ECs loaded with DAF-2 was determined using confocal microscopy. Accumulated NO in the culture medium was quantified by a microplate reader using membrane-impermeable DAF-2. Phosphorylation of endothelial NO synthase (eNOS) at Ser(1179) was assessed by Western blotting. Changes in intracellular Ca2+ ([Ca2+](i)) were determined by confocal microscopy in ECs doubly loaded with fluo-4 and Fura Red. The effects of aldosterone, acetylcholine (ACh), and other signaling molecules on the tension of phenylephrine (PE)-contracted aortas of Sprague-Dawley rats were examined in an ex vivo organ bath chamber system. Short-term pre-exposure to aldosterone (1 x 10(-7) mol/L) enhanced ATP-induced NO production in ECs with increased phosphorylation of eNOS at Ser(1179). These effects were blocked by eplerenone, a mineralocorticoid receptor (MR) antagonist, and LY294002, a phosphatidylinositol 3-kinase (PI3K) inhibitor. Notably, aldosterone alone did not affect ATP-induced [Ca2+](i), changes or the Ser(1179) phosphorylation. Similarly, aldosterone (1 x 10(-8) to 1 x 10(-7) mol/L) did not affect the tone of rat aortas pre-contracted by PE, but enhanced ACh-induced vasorelaxation, which was again reversed by eplerenone or LY29400. In contrast, sodium nitroprusside-induced vasorelaxation in endothelium-denuded aortas was not affected by aldosterone. Thus, aldosterone acutely enhances ligand-mediated endothelial NO production by eplerenone-sensitive mechanisms involving a PI3K that may synergize Ca2+-dependent eNOS phosphorylation at Ser(1179). (Hypertens Res 2008; 31: 1811-1820)