Recent studies indicate that the Kupffer cell plays a major role in the production of liver injury induced by a number of hepatotoxins and pathological conditions. Obliteration of Kupffer cells virtually abolishes cell necrosis and inflammation induced by xenobiotics such as ethanol, carbon tetrachloride and acetaminophen. Similarly, liver damage induced by endotoxemia or liver storage prior to transplantation is markedly reduced by experimental conditions that reduce Kupffer cell function. Data suggest that tumor necrosis factor-alpha released by Kupffer cells plays a major role in cell damage. The synthesis of tumor necrosis factor- alpha is initiated by gene-transcription factors, which are activated by oxygen radicals and endotoxin. Tumor necrosis factor-alpha triggers a cytokine cascade involving cytotoxic, inflammatory and fibrogenic mediators. The studies proposed (a) test the hypothesis that triple-helix targeting of the tumor necrosis factor-alpha gene in Kupffer cells results in marked reduction of liver damage induced by a number of hepatotoxins and pathogenic conditions; (b) develop methodologies for the design and delivery of triple-helix forming oligonucleotide drugs into Kupffer cells, for possible therapeutic use. Kupffer cells are specialized in the phagocytic removal of particulate matter from the circulation. Studies in this application utilize this phagocytic action to deliver liposome-entrapped triple-helix antigene oligonucleotides into Kupffer cells. The proposed research is designed to (i) suppress the synthesis of tumor necrosis factor-a and the cytokine transcription factor NF-kappaB in Kupffer cells, (ii) reduce the expression of genes involved in the generation of oxygen-radicals in Kupffer cells, and (iii) test the protection afforded by triple-helix drugs against liver necrosis and inflammation induced by the chronic administration of ethanol and other hepatotoxins. Overall, the proposed research investigates at the gene level the existence of central mechanisms of liver injury by new approaches with therapeutic potential for alcoholic liver disease in humans.
