Contribution of lysosomal vesicles to the formation of lipid raft redox signaling platforms in endothelial cells
Contribution of lysosomal vesicles to the formation of lipid raft redox signaling platforms in endothelial cells
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DOI：
10.1089/ars.2007.1660
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发表时间：
2007-09-01
影响因子：
6.6
通讯作者：
Li, Pin-Lan
中科院分区：
文献类型：
--
作者：
Jin, Si;Yi, Fan;Li, Pin-Lan
我们已经证明，脂质筏(LR)-氧化还原信号平台膜的形成与冠状动脉内皮细胞(CAECs)酸性鞘磷脂酶(ASMase)的激活有关。鉴于溶酶体小泡的运输可能在ASMase激活中起重要作用，本研究测试了溶酶体小泡是否有助于LR氧化还原信号平台的形成。在共聚焦显微镜下，我们发现Fas配体(FasL)诱导CAECs质膜上LR簇的形成，伴随着NAD(P)H氧化酶亚基、gp91(Phox)和P47(Phox)的聚集以及ROS的产生。用两种结构不同的溶酶体囊泡功能抑制剂BAF和甘氨酰-L-苯丙氨酸-β-萘胺(GPN)处理细胞时，FasL诱导的LRs聚集被显著阻断，相应的ROS产生显著减少。用LysoTracker共聚焦显微镜观察活体血管内皮细胞，发现LRs和溶酶体小泡共定位于细胞膜周围，这种共定位可被Baf或GPN消除。在功能上，两种溶酶体功能抑制剂均可减轻FasL对内皮依赖性血管松弛的抑制作用。这些结果提示，在死亡受体Fas激活过程中，溶酶体小泡参与了LR-氧化还原信号平台的形成，从而参与了内皮功能的氧化损伤。
We have demonstrated that the formation of lipid raft (LR)-redox signaling platforms membrane is associated with activation of acid sphingomyelinase (ASMase) in coronary arterial endothelial cells (CAECs). Given that the trafficking of lysosomal vesicles might play an essential role in ASMase activation, the present study tested whether lysosomal vesicles contribute to the formation of LR redox signaling platforms. By confocal microscopy, we found that Fas ligand (FasL) induced the formation of LR clusters in the plasma membrane of CAECs, accompanied by aggregation of NAD(P) H oxidase subunits, gp91(phox) and p47(phox), and ROS production. When the cells were pretreated with two structurally different lysosomal vesicle function inhibitors, bafilomycin A1 (Baf) and glycyl-L-phenylalanine-beta-naphthylamide (GPN), the FasL-induced LRs clustering was substantially blocked, and corresponding ROS production significantly decreased. By confocal microscopic observations in living CAECs by using LysoTracker, a colocalization of LRs and lysosomal vesicles was found around the cell membrane, which was abolished by Baf or GPN. Functionally, FasL-induced inhibition of endothelium-dependent vasorelaxation was also reduced by both inhibitors of lysosome function. These results suggest that lysosomal vesicles importantly contribute to the formation of LR-redox signaling platforms and thereby participate in the oxidative injury of endothelial function during activation of death receptor-Fas in coronary arteries.