Oxidized LDL induces mitochondrially associated reactive oxygen/nitrogen species formation in endothelial cells
Oxidized LDL induces mitochondrially associated reactive oxygen/nitrogen species formation in endothelial cells
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DOI：
10.1152/ajpheart.00015.2005
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发表时间：
2005-08-01
影响因子：
4.8
通讯作者：
Darley-Usmar, VM
中科院分区：
文献类型：
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作者：
Zmijewski, JW;Moellering, DR;Darley-Usmar, VM
细胞暴露于复杂的氧化脂质混合物中，如氧化低密度脂蛋白（oxLDL）中发现的那些，会诱导活性氧和氮种（ROS/RNS）的形成。细胞内ROS/RNS的来源尚不清楚；人们认为它们可能参与氧化还原细胞信号传导。虽然这种可能性最初被忽视了，但越来越清楚的是，线粒体作为超氧化物和过氧化氢的来源，可能在细胞暴露于氧化脂质的反应中起关键作用。在这项研究中，我们测试了线粒体是内皮细胞中氧化低密度脂蛋白依赖性ROS/RNS形成的潜在来源的可能性。使用共聚焦显微镜，我们证明了氧化低密度脂蛋白依赖的二氯二氢荧光素（DCF）荧光的显著比例是共定位到线粒体。为了支持这一概念，oxLDL刺激rho0内皮细胞的ROS/RNS形成显著减少。相反，在暴露于细胞外过氧化氢源的细胞中检测到大多数非线粒体DCF荧光。将细胞暴露于一氧化氮合酶抑制剂和尿酸盐中导致氧化低密度脂蛋白诱导的DCF荧光减少，这种荧光通过向培养基中添加一氧化氮供体而恢复。综上所述，这些结果表明，依赖于氧化低密度脂蛋白的DCF荧光与线粒体相关，可能是由于过氧亚硝酸盐的形成。
Exposure of cells to complex mixtures of oxidized lipids such as those found in oxidized low-density lipoprotein (oxLDL) induce reactive oxygen and nitrogen species (ROS/RNS) formation. The source of the ROS/RNS within cells is unknown; it is thought they may be involved in redox cell signaling. Although this possibility was initially overlooked, it is becoming clear that mitochondria, which are a source of superoxide and hydrogen peroxide, may play a critical role in the response of cells on exposure to oxidized lipids. In this study, we tested the possibility that mitochondria are a potential source of oxLDL-dependent formation of ROS/RNS in endothelial cells. Using confocal microscopy, we demonstrated that a significant proportion of oxLDL-dependent dichlorodihydrofluorescein (DCF) fluorescence is colocalized to mitochondria. In support of this concept, rho0 endothelial cells showed a substantial decrease in ROS/RNS formation stimulated by oxLDL. In contrast, mostly nonmitochondrial DCF fluorescence was detected in cells exposed to an extracellular source of hydrogen peroxide. The exposure of cells to a nitric oxide synthase inhibitor and urate resulted in a decrease in oxLDL-induced DCF fluorescence that was restored by addition of nitric oxide donors to the medium. Taken together, these results suggest that oxLDL-dependent DCF fluorescence is mitochondrially associated and may be due to the formation of peroxynitrite.