Papadimitriou E, Antimisiaris S G
Lab. of Molecular Pharmacology; Dept. of Pharmacy, School of Health Sciences, University of Patras, 26500 Patras, Greece.
J Drug Target. 2000;8(5):335-51. doi: 10.3109/10611860008997910.
Interactions between phosphatidylcholine (PC) or phosphatidylserine (PS) liposomes and human umbilical vein endothelial cells (HUVEC) or human promyelocytic leukemia cells (HL60) were investigated. Pyramine encapsulating or rhodamine incorporating small unilamellar liposomes with mean diameters around 80 nm (demonstrated to retain encapsulated material and to be nontoxic under experimental conditions) were used. Liposome uptake by both types of cells increased when increasing amounts of vesicles were co-incubated. For both lipid compositions, the interaction with HUVEC was very fast (association reached a plateau within 5 min) and so was the release of internalized vesicles (90% within 10 min at 37 degrees C). The reduced association values at 4 degrees C and the punctuate fluorescence observed in the cell cytoplasm after interaction, were indicative of whole liposome internalization. This internalization was clathrin-independent, since it was not inhibited by sodium azide and deoxyglucose. Pre-treatment of HUVEC with filipin or NEM resulted in modification of the interaction, something that could be due to alterations in the biochemical characteristics of HUVEC membranes that inhibit vesicular processes. In HL-60 cells, a slower association and faster release of PC/Chol liposomes was demonstrated, while association of both liposomes with these cells was energy-and temperature-independent. Nevertheless, morphological studies revealed differences in the interactions: A bright fluorescent rim observed after interaction with PC/Chol liposomes, suggests that these liposomes were adsorbed on the surface of HL60 cells, while the uniform cytoplasmic fluorescence observed after incubation with PS/Chol liposomes was indicative of fusion as the interaction mechanism.
研究了磷脂酰胆碱（PC）或磷脂酰丝氨酸（PS）脂质体与人类脐静脉内皮细胞（HUVEC）或人类早幼粒细胞白血病细胞（HL60）之间的相互作用。使用了包裹嘧啶或掺入罗丹明的平均直径约80nm的小单层脂质体（已证明在实验条件下能保留包裹的物质且无毒）。当共同孵育的囊泡量增加时，两种类型细胞对脂质体的摄取均增加。对于两种脂质组成，与HUVEC的相互作用非常迅速（5分钟内结合达到平台期），内化囊泡的释放也是如此（37℃下10分钟内释放90%）。4℃时结合值降低以及相互作用后在细胞质中观察到的点状荧光表明脂质体发生了整体内化。这种内化不依赖网格蛋白，因为它不受叠氮化钠和脱氧葡萄糖的抑制。用制霉菌素或NEM预处理HUVEC会导致相互作用发生改变，这可能是由于HUVEC膜的生化特性改变抑制了囊泡过程所致。在HL - 60细胞中，已证明PC/胆固醇脂质体的结合较慢且释放较快，而两种脂质体与这些细胞的结合均与能量和温度无关。然而，形态学研究揭示了相互作用的差异：与PC/胆固醇脂质体相互作用后观察到明亮的荧光边缘，表明这些脂质体吸附在HL60细胞表面，而与PS/胆固醇脂质体孵育后观察到的均匀细胞质荧光表明融合是相互作用机制。
