Alteration of plasmalemmal caveolae mimics endothelial dysfunction observed in atheromatous rabbit aorta
Alteration of plasmalemmal caveolae mimics endothelial dysfunction observed in atheromatous rabbit aorta
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DOI：
10.1016/s0008-6363(01)00251-6
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发表时间：
2001-06-01
影响因子：
10.8
通讯作者：
Arnal, JF
中科院分区：
文献类型：
--
作者：
Darblade, B;Caillaud, D;Arnal, JF
目的：在内皮细胞中，一氧化氮（NO）是由一氧化氮合酶（eNOS）的内皮异构体产生的，该异构体定位于参与信号转导的富含胆固醇的质层微域，称为小泡。本研究旨在评估高胆固醇血症和脂肪条纹形成对内皮小泡和内皮功能的影响，并试图确定小泡在多大程度上参与内皮源性NO的产生。方法与结果：我们首先研究了动脉粥样硬化对内皮细胞NO生成的影响。高胆固醇新西兰大白兔主动脉脂肪条纹浸润表现为乙酰胆碱诱导的舒张功能受损，而钙离子包体a23187诱导的最大舒张功能接近正常。覆盖脂肪条纹的内皮中小泡的丰度，以及它们的“葡萄状”簇状，似乎减少了。因此，我们研究了胆固醇结合剂2-羟丙基- β -环糊精（hp- β -CD）和filipin对内皮细胞NO生成的影响，已知它们可以改变小泡的结构和/或功能。hp- β -CD（2%）或filipin（4杯/毫升）治疗不影响对苯肾上腺素的收缩或对A23187或NO供体硝普钠的松弛反应，相反，两种治疗都损害了乙酰胆碱诱导的松弛。培养的牛主动脉内皮细胞（BAEC）同样用hp- β -CD处理，显示细胞总胆固醇降低50%，小泡的丰度减少，以及它们的“葡萄状”聚类。胆固醇消耗降低了缓激肽诱导的游离细胞内钙的瞬时峰值和随后的受体刺激的NO产生（使用富含可溶性鸟酰环化酶的报告细胞进行评估），而A23187诱导的峰值保持不变。结论：脂肪条纹沉积与小泡“转导体”丰度的减少有关，这似乎代表了内皮功能障碍的新机制。(C) 2001年Elsevier Science B.V.出版
Objectives: In endothelial cells, nitric oxide (NO) is produced by the endothelial isoform of nitric oxide synthase (eNOS), which is localized in the cholesterol-rich plasmalemmal microdomains involved in signal transduction, known as caveolae. The present study was undertaken to evaluate the effect of hypercholesterolemia and fatty streak formation on the endothelial caveolae and on endothelial function, and attempted to determine to what extent the caveolae were involved in endothelium-derived NO production. Methods and Results: We first studied the effect of atheroma on endothelial NO production. Fatty streak infiltrated aorta of cholesterol-fed New Zealand White rabbits demonstrated an impairment of acetylcholine-induced relaxation and nearly normal calcium ionophore A23187-induced maximal relaxation. The abundance of caveolae in the endothelium covering the fatty streak, as well as their 'grape-like' clustering, appeared to be decreased. We therefore investigated the effect, on endothelial NO production, of the cholesterol-binding agents 2-hydroxypropyl-beta -cyclodextrin (hp-beta -CD) and filipin, known to alter caveolae structure and/or function. Treatment with either hp-beta -CD (2%) or filipin (4 mug/ml) did not affect contraction to phenylephrine or relaxant responses to A23187 or to the NO donor sodium nitroprusside, In contrast, both treatments impaired acetylcholine-induced relaxation. Cultured bovine aortic endothelial cells (BAEC) similarly treated with hp-beta -CD demonstrated a 50% decrease of total cellular cholesterol and a decreased abundance of caveolae as well as their 'grape-like' clustering. Cholesterol depletion decreased the bradykinin-induced transient peak of free intracellular calcium and subsequent receptor-stimulated NO production (assessed using reporter cells rich in soluble guanylyl cyclase), whereas that elicited by A23187 remained unaltered. Conclusion: Fatty streak deposit is associated with a decrease in caveolae 'transductosomes' abundance which appears to represent a novel mechanism of endothelial dysfunction. (C) 2001 Published by Elsevier Science B.V.