The Use of Indolicidin-derived Peptides for Oligodeoxynucleotide Delivery

• Main Authors: Ju-Hui Chiu, 邱茹慧
• Other Authors: Wei-Wen Hu
• Format: Others
• Language: zh-TW
• Published: 2015
• Online Access: http://ndltd.ncl.edu.tw/handle/pjcc22

碩士 === 國立中央大學 === 化學工程與材料工程學系 === 103 === Indolicidin (IL)-derived peptides were studied of their effects on oligodeoxynucleotide (ODN) delivery. These peptides were either directly conjugated to (ODN) or grafted to branched PEI (bPEI) as polycation carriers. The peptide-ODN conjugates demonstrated low cytotoxicities, however, only the conjugates using ILC, CIL, and R57F89C were translocated. For the grafted bPEI method, these vehicles were complexed with (ODN) in different N/P ratios to form self-assembled nanoparticles through electrostatic interaction. Negative zeta potentials of formed nanocomplexes were found when the N/P ratios were low, suggesting anionic ODNs were adsorbed on the surfaces of polycations. The diameters of nanoparticles were smaller than 600 nm which were suitable for endocytosis. Compared to non-modified bPEI, bPEI conjugated to IL-derived peptides demonstrated superior biocompatibility. Fluorescence microscope and flow cytometry results indicated that both PEI-ILC and PEI-CIL promoted ODN internalization. Images captured by confocal microscope revealed that PEI-ILC and PEI-CIL were capable of delivering ODN to cytosol of host cells. Finally, these gene vehicles were applied to inhibit TNF-α expression. Because RAW264.7 cells were sensitive to polycations, the ODN delivered by these vehicles did not result in gene silence. Instead, the levels of expressed TNF-α were highly elicited. Only PEI-ILC in low N/P (N/P 5) significantly reduced TNF-α. These results suggested that PEI-ILC not only avoided to stimulate RAW264.7 cells but also promoted gene silence, which should be a potential vehicle for gene therapy application.