Cleavage of intracellular hepatitis C RNA in the virus core protein coding region by deoxyribozymes.

Hepatitis C virus (HCV) infection represents an important global health problem. Current antiviral therapeutics for HCV have proven inadequate in stemming the disease process. A novel therapeutic strategy involves the use of deoxyribozymes, also known as DNA enzymes or DNAzymes. These catalytic DNA molecules, designed to target and cleave specific RNA sequences, have shown promise in in vitro experimental models for various diseases and may serve as an alternative or adjunct to current HCV drug therapy. We designed and tested several deoxyribozymes that can bind and cleave highly conserved RNA sequences encoding the HCV core protein in in vitro systems. One of these deoxyribozymes reduced the level of our HCV RNA target by 32% and 48% after 24 h of cell exposure when tested in human hepatoma and epithelial cell lines, respectively. As this deoxyribozyme showed significant cleavage activity against HCV core protein target RNA in human cells, it may have potential as a therapeutic candidate for clinical trial in HCV infected patients.

Characterization and response to interleukin 1 and tumor necrosis factor of immortalized murine biliary epithelial cells.

BACKGROUND & AIMS: Biliary epithelial cells are the target of numerous immune-mediated liver diseases, yet their role in pathogenesis remains unclear because of difficulties in obtaining pure preparations. The aim of this study was to establish pure clones of immortalized murine intrahepatic biliary epithelial cells. METHODS: The transgenic mouse harboring the SV40 thermosensitive immortalizing mutant gene TsA58 under the control of the major histocompatibility complex class I promoter was used to establish conditionally immortalized intrahepatic bile duct cells by countercurrent centrifugal elutriation and clonal dilution. RESULTS: Immortalized clones of cells expressing cytokeratin 19, which organized themselves into ductlike structures, were obtained. On electron-microscopic sections, cells were well differentiated and polarized. Cells proliferate in response to epidermal growth factor, interleukin 1 alpha, and tumor necrosis factor alpha. Using the reverse-transcriptase polymerase chain reaction technique, these cells were found to contain messenger RNA, which encodes for the interleukin 1 and tumor necrosis factor receptors. CONCLUSIONS: The availability of unlimited numbers of pure bile duct cells that behave in an identical fashion to biliary epithelial cells from "normal" mice will allow for more rigorous studies of the behavior and function of this epithelium.