Abstract
The mechanism of interaction of artificially generated lipid vesicles (approximately 500 A diameter) with Chinese hamster V79 cells bathed in a simple balanced salt solution was investigated. The major pathways of exogenous lipid incorporation in vesicle-treated cells are vesicle-cell fusion and vesicle-cell lipid exchange. At 37 degrees C, the fusion process is dominant, while at 2 degrees C or with energy depleted cells, exchange of lipids between vesicles and cells is important. The fusion mechanism was demonstrated using vesicles of [14C]lecithin containing trapped [13H]inulin. Consistent with a fusion hypothesis, both components became cell associated at 37 degrees C in nearly the same proportions as they were present in the applied vesicles. Additional arguments in favor of vesicle-cell fusion and against phagocytosis or adsorption of intact vesicles are presented. At 2 degrees C or with inhibitor-treated cells, the [3H]inulin uptake was largely suppressed, while the lipid uptake was reduced to a lesser extent. Evidence for vesicle-cell lipid exchange was obtained using V79 cells grown on 3H precursors for cellular lipids. [14C]lecithin vesicles, incubated with such cells, showed no change in their elution properties when subjected to molecular sieve chromatography on Sepharose 4B. However, radioactivity and thin-layer chromatographic analyses revealed that a variety of cell lipiids had been exchanged into the uniamellar vesicles. Further evidence for the fusion and exchange processes was obtained using vesicles prepared from mixtures of [3H]lecithin and [14C]cholesterol. A two-step fusion mechanism consistent with the present findings is proposed as a working model for other fusion studies.
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Selected References
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- Allison A. G., Gregoriadis G. Liposomes as immunological adjuvants. Nature. 1974 Nov 15;252(5480):252–252. doi: 10.1038/252252a0. [DOI] [PubMed] [Google Scholar]
- Bruckdorfer K. R., Demel R. A., De Gier J., van Deenen L. L. The effect of partial replacements of membrane cholesterol by other steroids on the osmotic fragility and glycerol permeability of erythrocytes. Biochim Biophys Acta. 1969 Jul 15;183(2):334–345. doi: 10.1016/0005-2736(69)90089-3. [DOI] [PubMed] [Google Scholar]
- Gershfeld N. L., Good R. J. Line tension and the penetration of a cell membrane by an oil drop. J Theor Biol. 1967 Nov;17(2):246–251. doi: 10.1016/0022-5193(67)90170-1. [DOI] [PubMed] [Google Scholar]
- Grant C. W., McConnell H. M. Fusion of phospholipid vesicles with viable Acholeplasma laidlawii. Proc Natl Acad Sci U S A. 1973 Apr;70(4):1238–1240. doi: 10.1073/pnas.70.4.1238. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Gregoriadis G., Buckland R. A. Enzyme-containing liposomes alleviate a model for storage disease. Nature. 1973 Jul 20;244(5412):170–172. doi: 10.1038/244170a0. [DOI] [PubMed] [Google Scholar]
- Huang C. Studies on phosphatidylcholine vesicles. Formation and physical characteristics. Biochemistry. 1969 Jan;8(1):344–352. doi: 10.1021/bi00829a048. [DOI] [PubMed] [Google Scholar]
- Huang L., Pagano R. E. Interaction of phospholipid vesicles with cultured mammalial cells. I. Characteristics of uptake. J Cell Biol. 1975 Oct;67(1):38–48. doi: 10.1083/jcb.67.1.38. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Inbar M., Shinitzky M. Increase of cholesterol level in the surface membrane of lymphoma cells and its inhibitory effect on ascites tumor development. Proc Natl Acad Sci U S A. 1974 May;71(5):2128–2130. doi: 10.1073/pnas.71.5.2128. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Magee W. E., Goff C. W., Schoknecht J., Smith M. D., Cherian K. The interaction of cationic liposomes containing entrapped horseradish peroxidase with cells in culture. J Cell Biol. 1974 Nov;63(2 Pt 1):492–504. doi: 10.1083/jcb.63.2.492. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Martin F., MacDonald R. Liposomes can mimic virus membranes. Nature. 1974 Nov 8;252(5479):161–163. doi: 10.1038/252161a0. [DOI] [PubMed] [Google Scholar]
- PEARSON B., ANDREWS M., GROSE F. Histochemical demonstration of mammalian glucosidase by means of 3-(5-bromoindolyl)-beta-D-glucopyranoside. Proc Soc Exp Biol Med. 1961 Dec;108:619–623. doi: 10.3181/00379727-108-27014. [DOI] [PubMed] [Google Scholar]
- Pagano R. E., Huang L., Wey C. Interaction of phospholipid vesicles with cultured mammalian cells. Nature. 1974 Nov 8;252(5479):166–167. doi: 10.1038/252166a0. [DOI] [PubMed] [Google Scholar]
- Papahadjopoulos D., Mayhew E., Poste G., Smith S., Vail W. J. Incorporation of lipid vesicles by mammalian cells provides a potential method for modifying cell behaviour. Nature. 1974 Nov 8;252(5479):163–166. doi: 10.1038/252163a0. [DOI] [PubMed] [Google Scholar]
- Papahadjopoulos D., Poste G., Mayhew E. Cellular uptake of cyclic AMP captured within phospholipid vesicles and effect on cell-growth behaviour. Biochim Biophys Acta. 1974 Sep 23;363(3):404–418. doi: 10.1016/0005-2736(74)90079-0. [DOI] [PubMed] [Google Scholar]
- Papahadjopoulos D., Poste G., Schaeffer B. E. Fusion of mammalian cells by unilamellar lipid vesicles: inflluence of lipid surface charge, fluidity and cholesterol. Biochim Biophys Acta. 1973 Sep 27;323(1):23–42. doi: 10.1016/0005-2736(73)90429-x. [DOI] [PubMed] [Google Scholar]
- Pasternak C. A., Micklem K. J. Permeability changes during cell fusion. J Membr Biol. 1973;14(3):293–303. doi: 10.1007/BF01868082. [DOI] [PubMed] [Google Scholar]
- Peterson J. A., Rubin H. The exchange of phospholipids between cultured chick embryo fibroblasts and their growth medium. Exp Cell Res. 1969 Dec;58(2):365–378. doi: 10.1016/0014-4827(69)90517-5. [DOI] [PubMed] [Google Scholar]
- Raz A., Goldman R. Spontaneous fusion of rat liver lysosomes in vitro. Nature. 1974 Jan 25;247(5438):206–208. doi: 10.1038/247206a0. [DOI] [PubMed] [Google Scholar]
- Robbins P. W., Macpherson I. A. Glycolipid synthesis in normal and transformed animal cells. Proc R Soc Lond B Biol Sci. 1971 Feb 16;177(1046):49–58. doi: 10.1098/rspb.1971.0014. [DOI] [PubMed] [Google Scholar]
- Weissmann G., Bloomgarden D., Kaplan R., Cohen C., Hoffstein S., Collins T., Gotlieb A., Nagle D. A general method for the introduction of enzymes, by means of immunoglobulin-coated liposomes, into lysosomes of deficient cells. Proc Natl Acad Sci U S A. 1975 Jan;72(1):88–92. doi: 10.1073/pnas.72.1.88. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Wirtz K. W. Transfer of phospholipids between membranes. Biochim Biophys Acta. 1974 Sep 16;344(2):95–117. doi: 10.1016/0304-4157(74)90001-x. [DOI] [PubMed] [Google Scholar]