Adenovirus-mediated gene transfer to nonparenchymal cells in normal and injured liver

Adenovirus-mediated gene transfer has become an important tool with which to introduce genetic material into cells. Available data emphasize efficient adenoviral transduction of parenchymal liver cells (i.e., hepatocytes) in both in vitro and in vivo model systems, typically in normal cells. The aim of this study was to evaluate gene transfer to nonparenchymal (and parenchymal) cells of the normal and injured rat liver. Hepatocytes, stellate cells, and endothelial cells were isolated by standard methods. Liver injury was induced by bile duct ligation or carbon tetrachloride administration. Cells were transduced in vitro with an adenovirus encoding beta-galactosidase (Ad.beta-gal) over a range of viral titers, and transduced cells were identified by detection of X-gal. In vivo transduction efficiency was studied in normal and injured livers using cell isolation techniques. Nonparenchymal cells were transduced with greater frequency than hepatocytes at all adenoviral titers tested, both in vitro and in vivo. After liver injury, adenoviral transduction was reduced for all liver cell types compared with that for cells from normal livers (at all virus titers). Notably, transduction efficiency remained greater in nonparenchymal cells than in hepatocytes after liver injury. This work implies that, to achieve comparable gene expression in the injured liver, higher adenoviral titers may be required, an important consideration as gene therapy in disease states is considered.