Interaction of phospholipid vesicles with cultured mammalial cells. I. Characteristics of uptake
Interaction of phospholipid vesicles with cultured mammalial cells. I. Characteristics of uptake
复制标题
磷脂囊泡与培养的哺乳动物细胞的相互作用。
作者：
L. Huang;R. Pagano
检查了中国仓鼠V79细胞单层培养物与人工生成的单层脂质囊泡（直径约500 A）的相互作用。囊泡制备的各种天然和合成的放射性标记的磷脂酰胆碱（卵磷脂）与V79细胞在一个简单的平衡盐溶液中浸泡孵育。孵育后，分析细胞的外源性脂质掺入。大量（约10（8）分子/细胞/h）卵磷脂与细胞结合，而不影响细胞活力。pH值的影响，带电的脂质，和囊泡脂质相变的吸收过程中的影响进行了检查。在囊泡处理之前或在代谢抑制剂存在下孵育细胞的戊二醛固定未能将卵磷脂摄取降低超过25- 50%，表明脂质摄取在很大程度上是能量独立的。稀疏培养中的细胞比密集培养中的细胞吸收了大约十倍的脂质。稀疏细胞培养物与卵磷脂囊泡的长时间孵育（大于15小时）导致显著的细胞死亡，而在密集培养物或1：1卵磷脂/胆固醇囊泡中未发现有害作用。当囊泡处理的细胞均质化和分级分离，约20-30%的外源性脂质被发现在质膜部分，与其余的被分配到细胞内部分。电子显微镜放射自显影进一步证明，大部分内化的脂质存在于细胞质中，细胞核中很少。这些结果进行了讨论，在可能的修改细胞行为的脂质囊泡治疗。
The interaction of monolayer cultures of Chinese hamster V79 cells with artificially generated, unilamellar lipid vesicles (approximately 500 A diameter) was examined. Vesicles prepared from a variety of natural and synthetic radiolabeled phosphatidyl cholines (lecithins) were incubated with V79 cells bathed in a simple balanced salt solution. After incubation, the cells were analyzed for exogenous lipid incorporation. Large quantities (approximately 10(8) molecules/cell/h) of lecithin became cell associated without affecting cell viability. The effects of pH, charged lipids, and the influence of the vesicle lipid phase transition on the uptake process were examined. Glutaraldehyde fixation of cells before vesicle treatment, or incubation in the presence of metabolic inhibitors, failed to reduce the lecithin uptake by more than 25-50%, suggesting that the lipid uptake is largely energy independent. Cells in sparse culture took up about ten times more lipid than dense cultures. Prolonged incubation (greater than 15 h) of sparse cell cultures with lecithin vesicles resulted in significant cell death while no deleterious effect was found in dense cultures, or with 1:1 lecithin/cholesterol vesicles. When vesicle-treated cells were homogenized and fractionated, about 20-30% of the exogenous lipid was found in the plasma membrane fraction, with the remainder being distributed into intracellular fractions. Electron microscope radioautography further demonstrated that most of the internalized lipid was present in the cytoplasm, with little in the nucleus. These results are discussed in terms of possible modification of cell behavior by lipid vesicle treatment.