| Budget Amount *help |
¥3,830,000 (Direct Cost: ¥3,500,000、Indirect Cost: ¥330,000)
Fiscal Year 2007: ¥1,430,000 (Direct Cost: ¥1,100,000、Indirect Cost: ¥330,000)
Fiscal Year 2006: ¥2,400,000 (Direct Cost: ¥2,400,000)
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| Research Abstract |
The TV-XIIa-derived peptide vector [Ac-U-N-I-I-U-P-L-L-U-P-I-K-K-K-K-K-K-K-K-K-OH; Ac: acetyl, U: α-aminoisobutyric acid (Aib)], which is conjugated between TV-XIIa and a 10-mer of lysine (Lys), could deliver 20-mer oligonucleotides (ODN) into cells, and the 10-mer of Lys alone was not capable of delivering them. Then, TV-XIIa itself is consider to be an important role in the delivery system. To obtain the direct evidences for the cellular uptake of TV-XIIa itself and investigate the delivery principles of the 20-mer oligonucleotides, a fluorescein-labeled peptide with the TV-XIIa amino acid sequence was synthesized and applied to living cells to directly observe the behavior of TV-XIIa itself in living cells. Furthermore, to understand the importance of the three unusual Aib residues in the sequence, they were replaced with Ala, and the behavior of the Aib→Ala substitutional analog in living cells was also examined. The results indicated that the fluorescein-labeled TV-XIIa peptide can translocate into cells and the all replacement of Aib with Ala inhibits the cellular uptake. The translocation of the Aib-containing peptide seems to involve an energy-independent process. To optimize the 10-mer of lysine added as a ODN interaction part to TV-XIIa, the C-terminal moiety of the TV-XIIa-derived peptide vector was shortened to 8-, 6-, and 4-mers of Lys. The 4- and 6-mer derivatives cannot delivery ODNs into cells, on the other hand, the 8- and 10-mer derivatives significantly promote the uptake of ODNs. These results indicated that both the membrane permeability of TV-XIIa and the number of Lys residues might be important rolls to delivery the ODNs into cells
Next, amphiphatic 24-residual helix peptides [Ac-(U-U-U-K)6-NH2 and Ac-(U-U-K)8-NH2] were synthesized using a hydrophobic amino acid, Aib and a basic one, Lys. We found that the complexes, which were formed via electric-interaction between the helix peptides and ODNs, are taken up into cells.
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