Triggering role of acid sphingomyelinase in endothelial lysosome-membrane fusion and dysfunction in coronary arteries
Triggering role of acid sphingomyelinase in endothelial lysosome-membrane fusion and dysfunction in coronary arteries
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DOI：
10.1152/ajpheart.00958.2009
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发表时间：
2010-03-01
影响因子：
4.8
通讯作者：
Li, Pin-Lan
中科院分区：
文献类型：
--
作者：
Bao, Jun-Xiang;Xia, Min;Li, Pin-Lan
包建新，夏明，波克利斯 JL，韩文清，布里姆森 C，李 PL。酸性鞘磷脂酶在内皮溶酶体膜融合和冠状动脉功能障碍中的触发作用。 Am J Physiol Heart Circ Physiol 298：H992-H1002，2010。首次发表于 2010 年 1 月 8 日； doi:10.1152/ajpheart.00958.2009.-本研究确定酸性鞘磷脂酶 (ASM) 的激活是否会驱动近膜溶酶体与细胞表面融合，从而促进膜脂筏 (LR) 在冠状动脉内皮细胞 (CAEC) 中聚集并导致内皮功能障碍。通过共聚焦显微镜，发现 ASM 的激活剂磷脂酰肌醇 (PI) 和双（单酰基甘油）磷酸盐 (Bis) 以及 ASM 的诱导剂丁酸盐可以增加牛 CAEC 中的 LR 聚集，而这种作用被溶酶体融合抑制剂 vacuolin-1 阻断。然而，神经酰胺从头合成的诱导剂三氧化二砷（Ars）却没有这样的效果。类似地，使用荧光共振能量转移检测观察了vacuolin-1-阻断效应。液相色谱-电喷雾电离-串联质谱分析表明，所有这些治疗方法，甚至 Ars，都增加了 CAEC 中神经酰胺的产生。当 ASM 基因沉默时，除 Ars 之外的所有治疗都不再增加神经酰胺水平。此外，活细胞中的动态荧光监测表明，PI 和 Bis 刺激 CAEC 中的溶酶体-膜融合。在功能上，PI 和 Bis 损害灌注冠状动脉中内皮依赖性血管舒张，而这种血管舒张可被 vacuolin-1 和溶酶体功能抑制剂巴弗洛霉素阻断。 FasL（Fas配体），一种先前确认的溶酶体融合刺激剂作为比较，也产生了类似的效果。结论是ASM激活作为触发机制和驱动力，导致近膜溶酶体融合成CAEC细胞膜上的LR簇，这代表了死亡受体激活或其他病理情况下介导内皮功能障碍的新机制。
Bao JX, Xia M, Poklis JL, Han WQ, Brimson C, Li PL. Triggering role of acid sphingomyelinase in endothelial lysosome-membrane fusion and dysfunction in coronary arteries. Am J Physiol Heart Circ Physiol 298: H992-H1002, 2010. First published January 8, 2010; doi:10.1152/ajpheart.00958.2009.-The present study determined whether activation of acid sphingomyelinase (ASM) drives membrane proximal lysosomes to fuse to the cell surface, facilitating membrane lipid rafts (LRs) clustering in coronary arterial endothelial cells (CAECs) and leading to endothelial dysfunction. By confocal microscopy, the activators of ASM, phosphatidylinositol (PI), and bis (monoacylglyceryl) phosphate (Bis), and an inducer of ASM, butyrate, were found to increase LRs clustering in bovine CAECs, which was blocked by lysosome fusion inhibitor vacuolin-1. However, arsenic trioxide (Ars), an inducer of de novo synthesis of ceramide, had no such effect. Similarly, vacuolin-1-blockable effects were observed using fluorescence resonance energy transfer detection. Liquid chromatography-electrospray ionization-tandem mass spectrometry analysis demonstrated that all of these treatments, even Ars, increased ceramide production in CAECs. When ASM gene was silenced, all treatments except Ars no longer increased ceramide levels. Furthermore, dynamic fluorescence monitoring in live cells showed that PI and Bis stimulated lysosome-membrane fusion in CAECs. Functionally, PI and Bis impaired endothelium-dependent vasodilation in perfused coronary arteries, which was blocked by vacuolin-1 and a lysosome function inhibitor, bafilomycine. FasL (Fas ligand), a previously confirmed lysosome fusion stimulator as a comparison, also produced a similar effect. It is concluded that ASM activation serves as a triggering mechanism and driving force, leading to fusion of membrane proximal lysosomes into LR clusters on the cell membrane of CAECs, which represents a novel mechanism mediating endothelial dysfunction during death receptor activation or other pathological situation.