| Co-Investigator(Kenkyū-buntansha) |
TSUTSUMI Yasuo Osaka University, Faculty and Graduate School of Pharmaceutical Sciences, Resear, 薬学部, 助手 (50263306)
NAKAGAWA Shinsaku Osaka University, Faculty and Graduate School of Pharmaceutical Sciences, Assist, 薬学部, 講師 (70207728)
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| Budget Amount *help |
¥1,800,000 (Direct Cost: ¥1,800,000)
Fiscal Year 1996: ¥1,800,000 (Direct Cost: ¥1,800,000)
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| Research Abstract |
Many investigators have examined liposomes as carriers for transporting substances into cells. However, conventional liposomes do not directly fuse with the cell membrane. Even when they are actively bound to the cell surface by adding an antibody or ligand on the surface, they are taken into the cell by endocytosis. Therefore, most substances encapsulated in liposomes are degraded by lysosome enzymes, resulting in loss of their efficiency. On the other hand, the envelope of the Sendai virus contains a protein responsible for binding and fusion to the cell membrane, and Sendai virus genes are introduced into cells via membrane fusion. Therefore, the introduced genes are not decomposed by lysomome enzymes. Based on these findings, fusogenic liposomes which possess the envelope proteins of the Sendai virus on the liposomal surface were developed. Fusogenic liposomes can introduce their encapsulated materials into the cytoplasm through direct membrane fusion. In this study, we examined th
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e preparation and characterization of unilamellar fusogenic liposome, and the efficiency of delivery of proteins and DNA by unilamellar fusogenic liposomes.
A fusogenic liposome was generated by fusion between a Sendai virus particle and a simple liposome (PA : PC : CHOL=1 : 4 : 5 (mol)). The liposomes with a negative surface charge of phosphatidic acid (PA) gave the best results. The amount of cholesterol (30-50%) and the presence of sialic acid did not affect the efficiency of delivery. In addition, we purified fusogenic liposomes based on the difference of the density of the particles. The purified fusogenic liposomes are similar in size and structure to the Sendai virus particle, and fuse with cells as efficiently as the Sendai virus. These liposomes can fuse with cells derived from various species (human, monkey, rabbit, canine, cattle, mouse and hamster) and from various tissues (fibroblasts, epithelial cells, endothelial cells, hepatocytes, neuronal cells and lymphoma cells) with almost the same efficiency. They can deliver any substances that can be encapsulated in the liposomes, including genes or proteins, into the cells.
In conclusion, the fusogenic lipsomes are new tools for direct introduction of genetic information into animal tissues. Less
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