Exogenous expression of hepatocyte growth factor (HGF) in rat striatum by naked plasmid DNA

Hepatocyte growth factor (HGF) is a heterodimeric protein and shows mitogenic and morphogenic activities toward a variety of epithelial cells. There has been no immunohistochemical evidences for naked DNA mediated transgene expression of HGF into central nervous system. We initially demonstrated a naked plasmid mediated expression of HGF into rat striatum. The immunofluorescence staining revealed that exogenous protein of human HGF was expressed at 7 days after plasmid injection (300 microg). Exogenous HGF was mainly expressed in reactive astrocytes according to dual-labeling staining of HGF and glial fibrillary acidic protein or S100. It is also demonstrated that c-met, specific receptor of HGF, was expressed in the injection site. Intensive expression of c-met was found in the site to which HGF encoded plasmid was injected. These evidences for the exogenous expression of HGF and its receptor c-met may implicate an application of naked plasmid mediated HGF for neuronal disease as well as the other neurotrophic factors.