Efficient delivery of HBV NLS siRNAs into HepG2.2.15 cells for HBV inhibition through novel recombinant preS1tP proteins

Hepatitis B virus (HBV) infection and related liver complications remain severe public health problems worldwide. Previous investigations have shown that small interfering (si)RNAs can offer an effective strategy for the treatment of chronic hepatitis B. The present study aimed to develop a novel siRNAdelivering system of therapeutic HBV nuclear localization sequence (NLS) siRNAs using the recombinant preS1truncated protamine (tP) proteins. The preS1 region of the LHB was used in place of scFv to construct the recombinant preS1tP proteins, which were applied to deliver siRNAs targeting the HBV NLS to inhibit HBV replication and infection in HepG2.2.15 cells overexpressing sodium taurocholate cotransporting polypeptide (NTCP). The results revealed that HepG2.2.15 cells with stable NTCP expression (HepG2.2.15NTCP cells) transfected with the recombinant lentivirus showed increased expression of NTCP genes. The HBV NLS siRNAs significantly suppressed HBV mRNA content and levels of HBsAg and HBeAg in the HepG2.2.15NTCP cells. Recombinant preS1tP proteins tagged with His and glutathione Stransferase were found to enter into HepG2.2.15NTCP cells and bind with DNA. The HBV NLS siRNAs were delivered into HepG2.2.15NTCP cells by recombinant preS1tP proteins, which resulted in decreased expression of HBV mRNA, HBsAg and HBeAg, HBV DNA and covalently closed circular DNA in the HepG2.2.15NTCP cells. Therefore, the recombinant preS1tP proteins successfully delivered NLS siRNAs into HepG2.2.15 cells and repressed HBV infection and replication.