SiRNA-Loaded Nucleic Acid Lipid Nanoparticles For Targeted Diagnosis And Treatment Of Liver Cirrhosis And Tumor

RNA interference technology can silence any gene expression by using small interfering RNA(siRNA),which has high specificity and high efficiency.However,siRNA is negatively charged,highly susceptible to degradation,and lacks targeting.From the first demonstration of siRNA in 1998 to the first siRNA drug approved in 2018,the development process is very slow.Although several siRNA drugs have been approved for marketing,there are still many problems.For example,lack of siRNA drugs that can effectively treat liver cirrhosis,unable to monitor the site and time at which siRNA drugs work.To develop siRNA drugs that can effectively treat cirrhosis,we constructed a SNALP(stable nucleic acid lipid nanoparticles)delivery system capable of delivering HMGB1-siRNAs to hepatic stellate cells.First,a targeted lipid molecule DSPE-PEG-p PB was synthesized,and the p PB polypeptide in the molecule specifically recognizes the PDGFR-? receptor on the surface of activated hepatic stellate cells.Then prepare an oil phase containing 5 lipid molecules and an aqueous phase containing siRNA,mix the aqueous phase with the oil phase in a T-tube,the siRNA is firmly encapsulated inside to form the nucleic acid lipid nanoparticle(HMGB1-siRNA@SNALP-p PB).The results of in vivo imaging and confocal imaging experiments demonstrate that the nanoparticles can efficiently deliver siRNA to activated hepatic stellate cells.Pharmacodynamic results show that thenanoparticles can effectively reduce the degree of fibrosis in liver and prolong the survival time of mice.In order to monitor the site and time at which siRNA drugs work,we developed a SNALP delivery system loaded with gold nanoparticles and Survivin-siRNA based on the previous study.Firstly,gold nanoparticles were prepared.The Au-DR-siRNA is formed by the chemical coordination bond between the thiol group and the gold nanoparticle.The fluorescence of the Cy5 is quenched by the fluorescence resonance energy transfer effect and cannot be detected by external instrument.The Au-DR-siRNA@SNALP is formed by the electrostatic attraction between the cationic lipid and the negatively charged Au-DR-siRNA and the hydrophilic and hydrophobic interaction of the lipid molecule.The experimental results show that in the aspect of monitoring,the nanoparticles can effectively protect the internal siRNA from being cleavage by ribozyme in the blood,so that the fluorescence of Cy5 is quenched within 48 hours.Au-DR-siRNA can rapidly restore fluorescence under the action of Dicer.In terms of treatment,the pharmacodynamic results indicate that the siRNA taken up by the tumor cells can silence the Survivin gene to exert an anti-tumor effect.The CT imaging function of the nanoparticles is superior to iohexol.In the above two studies,through rational and clever design,it provides a new idea for solving the bottleneck problems encountered in the current siRNA drug development process,and has a guiding role in the treatment of liver cirrhosis and the integration of diagnosis and treatment of tumors.