Objectives: To investigate whether HDV ribozymes can intracellularly inhibit HCV RNA.
Methods: The mammalian expression vectors, pC1-RzC1, pC1-RzC2 and pC1-RzC3, containing ribozymes cDNA of RzC1, RzC2, and RzC3, were constructed targeting different HCV-5' NCR-C RNA regions. Then the HCV-positive fetal hepatocytes were transfected with these plasmids using liposome-mediated method. The inhibitory effects of HDV ribozymes were evaluated by HCV RNA quantitation in cultured cells and the supernatants.
Results: (1) All the three HDV ribozymes were inserted into the expression vector. (2) Fetal hepatocytes were infected with HCV proven by RT-PCR and fluorescent quantitative PCR and expressed HCV NS3 and NS5 antigens by immunocytochemistry. (3) HDV ribozymes inhibited the activity of the target HCV RNA at expect positions in HCV-positive hepatocytes. At 0.5 micromol/L, the inhibitory rate of pC1-RzC1, pC1-RzC2, and pC1-RzC3 was 53.2%, 50.5 %, and 10.6% respectively. PC1-RzC1 was used continuously for one week, showing the inhibitory rate of 60.7%, 64.2%, 68.4%, 71.9%, 78.8% and 83.1% on the 2nd, 3rd, 4th, 5th, 6th and 7th day.
Conclusion: The inhibitory activity of pC1-RzC1 (107-113nt) and pC1-RzC2 (268-274nt) is greater than that of pC1-RzC3 (345-351nt) in HCV-positive hepatocytes.