Syntheses and Properties of Formyl Peptide for Gene Delivery

MasterCuring HIV infection has remained a difficult goal due to low drug absorption, drug toxicity, and the presence of viral reservoirs. Currently, RNA interference (RNAi) is the most spotlight nucleic acids based method in anti-HIV drug research. The technique regulating expression of specific gene by small interfering RNA (siRNA) is useful to treat inherited diseases such as genetic defect and abnormal gene expression. The limitations, however, in gene therapy are that naked siRNA is difficult to penetrate plasma membrane and has low targeting to specific cell. And it has low stability due to degradation by various enzymes in vivo. To overcome the obstacles of gene therapy, we modified siRNA by using peptides which have some advantages. Peptides can enhance siRNA stability as a non-viral carrier and delivery siRNA to specific cell as a ligand by ligand-receptor interaction. And they have low cytotoxicity compared to viral transfection agents. In our research, we used N-formyl-Met-Leu-Phe (fMLF) peptide to target macrophage which is a major reservoir for HIV replication and express formyl peptide receptor. To check cellular uptake of siRNA, we introduced multiple copies of fMLF into siRNA. By using formyl peptide, we synthesized peptide-siRNA conjugations and peptide-siRNA complexes. And we discussed the physical and biological properties of them for gene delivery. In cellular uptake studies, complexes containing four copies of fMLF showed the highest uptake, enhancing interaction between complexes and plasma membrane of cells. The results of the current studies indicate that hydrophobic part of fMLF peptide and cationic part of arginine, lysine peptide play important roles to form complexes with siRNA efficiently and increase cellular uptake. To understand cellular uptake mechanisms like receptor-mediated endocytosis, additional studies are needed