GENE-EXPRESSION FOLLOWING DIRECT-INJECTION OF DNA INTO LIVER

The liver is an attractive target tissue for gene therapy, Current app roaches for hepatic gene delivery include retroviral and adenoviral ve ctors, liposome/DNA, and peptide/DNA complexes, This study describes a technique for direct injection of DNA into liver that led to signific ant gene expression, Gene expression was characterized in both rats an d cats following injection of plasmid DNA encoding several different p roteins, Luciferase activity was measured after injection of plasmid D NA encoding the luciferase gene (pCMVL), beta-galactosidase (beta-Gal) activity was evaluated in situ using plasmid DNA encoding Lac Z (pCMV beta), and serum concentration of secreted human alpha-1-antitrypsin was measured following injection of plasmid DNA encoding this protein (pRC/CMV-sHAT), Several variables, including injection technique, DNA dose, and DNA diluent, were investigated, Direct injection of pCMVL re sulted in maximal luciferase expression at 24-48 hr. beta-Gal staining demonstrated that the majority of transfected hepatocytes were locate d near the injection site. Significant concentrations of human alpha-1 -antitrypsin were detected in the serum of animals injected with pRC/C MV-sHAT, These findings demonstrate the general principle that direct injection of plasmid DNA into liver can lead to significant gene expre ssion.