Optimization of siRNA Delivery Method into the Liver by Sequential Injection of Polyglutamic Acid and Cationic Lipoplex

Abstract

Previously, we developed a novel siRNA transfer method to the liver by sequential intravenous injection of poly-L-glutamic acid (PGA) and cationic liposome/siRNA complex (cationic lipoplex). In this study, we examined the effects of the charge ratio (+/−) of cationic liposome/siRNA, molecular weight of PGA and cationic lipid of cationic liposome on the biodistribution of siRNA after sequential injection of PGA plus cationic lipoplex. When 1,2-dioleoyl-3-trimethylammonium-propane (DOTAP)/cholesterol (Chol) lipoplex was intravenously injected into mice, the accumulation of siRNA was mainly observed in the lungs. In contrast, when DOTAP/Chol lipoplex was intravenously injected at 1 min after intravenous injection of PGA, siRNA was largely accumulated in the liver

Progress in the development of Lipoplex and Polyplex modified with Anionic Polymer for efficient Gene Delivery

“…Moreover, intramuscular, intraperitoneal, or subcutaneous injection of CS into mice before intravenous injection of DOTAP/Chol lipoplexes also resulted in siRNA accumulation mainly in the liver [88]. We found that regardless of the injection route of CS, the concentration of CS in serum needed to [86][87][88]. In sequential injection, at 1 min after intravenous injection of 1 mg CS or αPGA, DOTAP/Chol lipoplexes with Cy5.5-labeled siRNA (Cy5.5-siRNA) were administered intravenously to mice [86][87][88].…”

“…We found that regardless of the injection route of CS, the concentration of CS in serum needed to [86][87][88]. In sequential injection, at 1 min after intravenous injection of 1 mg CS or αPGA, DOTAP/Chol lipoplexes with Cy5.5-labeled siRNA (Cy5.5-siRNA) were administered intravenously to mice [86][87][88]. Ex vivo images of dissected tissues (A) and tissue sections (lung and liver) (B) were obtained at 1 h after injection of siRNA lipoplexes.…”

“…Therefore, we developed a sequential injection method that cationic lipoplexes with siRNA were injected intravenously soon after intravenous injection of anionic polymer. For example, intravenous injection of DOTAP/Chol lipoplexes induced large accumulation in the lungs ( Figure 6A and 7); however, intravenous injection of 1 mg CS or αPGA into mice, followed by intravenous injection of DOTAP/Chol lipoplexes at a 1 min interval delivered siRNA to the liver ef iciently without accumulation in the lungs ( Figure 6C and 7) [86,87]. This method has an advantage of not requiring preparation of ternary complexes, which is sometimes unstable in solution, by neutralizing the surface charge of the lipoplexes.…”

“…This method has an advantage of not requiring preparation of ternary complexes, which is sometimes unstable in solution, by neutralizing the surface charge of the lipoplexes. Regarding the liposomal formulation, cationic liposomes composed of DOTAP/DOPE, DOTMA/Chol, dimethyldioctade-cylammonium bromide (DDAB)/Chol and O,O'-ditetradecanoyl-N-(α-trimethylammonioacetyl) diethanolamine chloride (DC-6-14)/Chol could also ef iciently deliver siRNAs into the liver by sequential injection with αPGA [87]. Moreover, intramuscular, intraperitoneal, or subcutaneous injection of CS into mice before intravenous injection of DOTAP/Chol lipoplexes also resulted in siRNA accumulation mainly in the liver [88].…”

Evaluation of the injection route of an anionic polymer for small interfering RNA delivery into the liver by sequential injection of anionic polymer and cationic lipoplex of small interfering RNA

“…Previously, we developed a ternary complex of siRNA, cationic liposomes, and anionic polymer, and we found that chondroitin sulfate C (CS-C) or PGA coating of the cationic lipoplex produced safe systemic vectors [10]. Recently, we reported that intravenous injection of cationic lipoplex 1 min after intravenous injection of CS-C or PGA into mice could deliver siRNA to the liver efficiently without accumulation in the lungs [11,12]. However, it was not clear whether siRNA delivery into the liver by sequential injection of anionic polymer plus cationic lipoplex was affected by the injection route of the anionic polymer.…”