LIPID TRAFFIC BETWEEN HIGH-DENSITY-LIPOPROTEINS AND PLASMODIUM-FALCIPARUM-INFECTED RED-BLOOD-CELLS
LIPID TRAFFIC BETWEEN HIGH-DENSITY-LIPOPROTEINS AND PLASMODIUM-FALCIPARUM-INFECTED RED-BLOOD-CELLS
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DOI：
10.1083/jcb.112.2.267
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发表时间：
1991-01-01
影响因子：
7.8
通讯作者：
SCHREVEL, J
中科院分区：
文献类型：
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作者：
GRELLIER, P;RIGOMIER, D;SCHREVEL, J
在体外，只添加人高密度脂蛋白（HDL）部分（d = 1.063-1.210）的无血清培养基可以实现恶性疟原虫的几个红细胞内生长周期。所得寄生虫率与含人血清的标准培养基相似。低密度脂蛋白（LDL）部分的寄生虫发育不完全，而VLDL部分则没有发生。通过脉冲标记实验，用装载荧光nbd -磷脂酰胆碱（NBD-PC）或放射性[H-3]棕榈酰胆碱的高密度脂蛋白，证明了从HDL到感染红细胞的脂质运输。在37摄氏度时，脂质探针在感染细胞中迅速积聚。在含有标记PC的HDL培养基中孵育后，随后在含有过量的天然HDL或20%的人血清的培养基中孵育，诱导红细胞膜上的标记消失，但红细胞内寄生虫没有消失。在4摄氏度时，脂质的内化没有发生。其机制与脂质单向流动有关，但与内吞作用无关。通过免疫荧光和免疫印迹检测，高密度脂蛋白先前在载脂蛋白上碘化[I-125]或针对载脂蛋白AI和AII的抗体，没有标记恶性疟原虫，证实HDL不参与内吞作用。脂质运输的可能途径可能是膜通量，因为荧光视频显微镜显示许多标记有NBD-PC的细胞器在红细胞和寄生膜之间移动。薄层色谱分析显示，[H-3]棕榈酰PC- hdl脉冲后，恶性疟原虫感染的红细胞中PC部分转化为磷脂酰乙醇胺。脂质运输的强度是阶段依赖性的，在滋养体和幼裂殖体阶段（红细胞生命周期的第38 h）最大。我们得出结论，HDL部分似乎是疟原虫生长的主要脂质来源。
Several intraerythrocxytic growth cycles of Plasmodium falciparum could be achieved in vitro using a serum free medium supplemented only with a human high density lipoprotein (HDL) fraction (d = 1.063-1.210). The parasitemia obtained was similar to that in standard culture medium containing human serum. The parasite development was incomplete with the low density lipoprotein (LDL) fraction and did not occur with the VLDL fraction. The lipid traffic from HDL to the infected erythrocytes was demonstrated by pulse labeling experiments using HDL loaded with either fluorescent NBD-phosphatidylcholine (NBD-PC) or radioactive [H-3]palmitoyl-PC. At 37-degrees-C, the lipid probes rapidly accumulated in the infected cells. After incubation in HDL medium containing labeled PC, a subsequent incubation in medium with either an excess of native HDL or 20% human serum induced the disappearance of the label from the erythrocyte plasma membrane but not from the intraerythrocytic parasite. Internalization of lipids did not occur at 4-degrees-C. The mechanism involved a unidirectional flux of lipids but no endocytosis. The absence of labeling of P. falciparum, with HDL previously [I-125]iodinated on their apolipoproteins or with antibodies against the apolipoproteins AI and AII by immunofluorescence and immunoblotting, confirmed that no endocytosis of the HDL was involved. A possible pathway of lipid transport could be a membrane flux since fluorescence videomicroscopy showed numerous organelles labeled with NBD-PC moving between the erythrocyte and the parasitophorous membranes. TLC analysis showed that a partial conversion of the PC to phosphatidylethanolamine was observed in P. falcipa-rum-infected red cells after pulse with [H-3]palmitoyl-PC-HDL. The intensity of the lipid traffic was stage dependent with a maximum at the trophozoite and young schizont stages (38th h of the erythrocyte life cycle). We conclude that the HDL fraction appears to be a major lipid source for Plasmodium growth.