Human α 1-Antitrypsin Gene Transfer to In Vivo Mouse Hepatocytes

Abstract

The in vivo gene transfer to mouse hepatocytes of pTG 7101, a plasmid containing the full-length gene encoding human α1-antitrypsin (α1-AT) DNA, has been studied by iv administration of recombinant DNA (100 ng/mouse) encapsulated in large and small liposomes. Our results from immunohistochemical liver sections and cytophotometric analysis of hepatocyte chromophore absorbance indicate that human α1-AT was expressed in liver parenchymal cells from mice treated (48 hr before) with DNA encapsulated in small liposomes, and this effect remained for at least 2 weeks. In contrast, the efficiency was greatly limited when large liposomes were used as a vehicle for gene transfer. Additional experiments were performed to study using an ELISA procedure the presence in mouse plasma of human α1-AT from mice treated with encapsulated plasmid in small liposomes or small empty liposomes plus free DNA. According to the immunohistochemical data, the results indicate that detectable α1-AT can only be observed in plasma from mice treated with encapsulated plasmid in small liposomes.

Overview summary

We studied the effect of in vivo gene transfer into mouse hepatocytes of pTG 7101, a plasmid containing the full-length human α1-antitrypsin (α1-AT) gene, by iv administration of recombinant DNA encapsulated in large versus small liposomes. Immunohistochemical and cytophotometric analysis of hepatocytes showed human α1-AT expression only in the liver of mice treated with DNA encapsulated in small liposomes. This expression persisted for 2 weeks. In contrast, when large liposomes were used, the efficiency was greatly reduced. Additionally, plasma levels of human α1-AT could be detected only in mice injected with the plasmid encapsulated in small liposomes.