Coincident exposure of phosphatidylethanolamine and anionic phospholipids on the surface of irradiated cells
Coincident exposure of phosphatidylethanolamine and anionic phospholipids on the surface of irradiated cells
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DOI：
10.1016/j.bbamem.2008.05.006
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发表时间：
2008-10-01
影响因子：
3.4
通讯作者：
Thorpe, Philip E.
中科院分区：
文献类型：
--
作者：
Marconescu, Andrei;Thorpe, Philip E.
主要的阴离子磷脂，磷脂酰丝氨酸（PS），和中性磷脂，磷脂酰乙醇胺（PE），主要局限于内小叶的质膜双层在哺乳动物细胞在正常条件下。当细胞发生凋亡时，这种不对称性消失。被激活或暴露于辐射、活性氧或某些药物。尚不清楚阴离子磷脂（APLs）和PE的暴露是否同时发生或发生在质膜的同一区域。在这里，我们研究了照射后，牛主动脉内皮细胞和NSO骨髓瘤细胞表面的APLs和PE暴露的一致性。照射细胞（5戈伊），并使用包被有PS结合抗体（bavituximab）的Fab'片段或PE结合肽（duramycin）的脂质体对APL和PE染色。使用活细胞成像和流式细胞术，我们表明，照射导致同步的外部化的APLs和PE。APLs和PE在细胞表面上出现的时间过程是相同的，并且两种磷脂类型随着时间的推移保持共定位。可见明显的APLs和PE双阳性斑块。大面积的APLs和PE似乎已经脱离细胞骨架，形成膜泡，这些膜泡突出并漂浮在细胞表面。我们的结论是，APLs和PE同时出现在照射后的细胞质膜的外部小叶。这可能是因为PE和主要的APL PS具有共同的易位调节机制。(c)2008 Elsevier B.V.保留所有权利。
The major anionic phospholipid, phosphatidylserine (PS), and the neutral phospholipid, phosphatidylethanolamine (PE), are largely confined to the inner leaflet of the plasma membrane bilayer in mammalian cells under normal conditions. This asymmetry is lost when cells undergo apoptosis. become activated, or are exposed to irradiation, reactive oxygen species or certain drugs. It is not known whether exposure of anionic phospholipids (APLs) and PE occurs simultaneously or in the same region of the plasma membrane. Here we examined the coincidence of exposure of APLs and PE on the surface of bovine aortic endothelial cells and NSO myeloma cells after irradiation. The cells were irradiated (5 Gy) and stained for APLs and PE using liposomes coated with either an Fab' fragment of a PS-binding antibody (bavituximab) or a PE-binding peptide (duramycin). Using live cell imaging and flow cytometry, we showed that irradiation leads to synchronous externalization of APLs and PE. The time course of appearance of APLs and PE on the cell surface was the same and the two phospholipid types remained colocalized over time. Distinct patches double positive for APLs and PE were visible. Larger areas of APLs and PE appeared to have detached from the cytoskeleton to form-membrane blebs which protruded and drifted on the cell surface. We conclude that APLs and PE coincidently appear on the external leaflet of the plasma membrane of cells after irradiation. Probably, this is because PE and the major APL, PS, share common regulatory mechanisms of translocation. (c) 2008 Elsevier B.V. All rights reserved.