Abstract
Hepatitis B virus (HBV), an international public health concern, is a leading viral cause of liver disease, such as hepatocellular carcinoma. Sequence-specific ribozymes derived from ribonuclease P (RNase P) catalytic RNA are being explored for gene targeting applications. In this study, we engineered an active RNase P ribozyme, M1-S-A, targeting the overlapping region of HBV S mRNA, pre-S/L mRNA, and pregenomic RNA (pgRNA), all deemed essential for viral infection. Ribozyme M1-S-A cleaved the S mRNA sequence efficiently in vitro. We studied the effect of RNase P ribozyme on HBV gene expression and replication using the human hepatocyte HepG2.2.15 culture model that harbors an HBV genome and supports HBV replication. In these cultured cells, the expression of M1-S-A resulted in a reduction of more than 80% in both HBV RNA and protein levels and an inhibition of about 300-fold in the capsid-associated HBV DNA levels when compared to the cells that did not express any ribozymes. In control experiments, cells expressing an inactive control ribozyme displayed little impact on HBV RNA and protein levels, and on capsid-associated viral DNA levels. Our study signifies that RNase P ribozyme can suppress HBV gene expression and replication, implying the promise of RNase P ribozymes for anti-HBV therapy.