Lentivirus-mediated superoxide dismutase1 gene delivery protects against oxidative stress-induced liver injury in mice.

BACKGROUND: The exposure of liver to hepatotoxins, and their subsequent metabolism, results in increased reactive oxygen species (ROS), one of the major culprits in causing both acute liver cell injury and chronic liver diseases. The aim of this present study is to investigate the protective effects of lentiviral vector-mediated copper-zinc superoxide dismutase (LV-SOD1) gene transfer against ROS-induced cytotoxicity in Hep G2 cells and liver injury in mice. METHODS: In vitro SOD1 efficacy was tested against two ROS-generating systems: hypoxanthine/xanthine oxidase (HX/XO) and hydroxyethyl radicals (HER), whereas in vivo SOD1 efficacy was evaluated in carbon tetrachloride (CCl4)-induced liver injury in C57BL/6 mice. RESULTS: LV-SOD1 transduction in Hep G2 cells resulted in a significant increase in SOD activity in cell lysates, and it significantly decreased the toxicity induced by HX/XO and HER. High SOD1 expression in the liver was achieved via portal vein injection of LV-SOD1 in mice and these high levels were observed for 30 days, the length of the experiment to date. SOD1 overexpression significantly decreased the toxicity and restored liver function in the CCl4-treated mice. CONCLUSIONS: These findings demonstrate for the first time that LV transduction led to the long-term expression of fully functional transgene expression in both in vitro and in vivo systems.

Gene therapy for human alpha1-antitrypsin deficiency in an animal model using SV40-derived vectors.

BACKGROUND & AIMS: In most genetic diseases, the goal of gene therapy is to deliver a particular transgene; however, sometimes a deleterious gene product must be eliminated. Because of the promise of recombinant simian virus 40 (rSV40) vectors, we tested their ability to deliver a transgene and to target a transcript for destruction by direct administration of the vectors to the liver of an animal model for human alpha1-antitrypsin (alpha1-AT) deficiency. METHODS: Therapy of human alpha1-AT deficiency requires stable transduction of resting hepatocytes, both to deliver wild-type alpha1-AT and to inhibit production of mutant alpha1-AT. Transgenic mice carrying the mutant human alpha1-AT PiZ allele were treated through an indwelling portal vein catheter with a simian virus 40 (SV40)-derived vector carrying a ribozyme designed to target the human transcript. RESULTS: Treated transgenic mice showed marked decreases of human alpha1-AT messenger RNA and the protein in the liver, and serum levels of human alpha1-AT were decreased to 50% +/- 5% of pretreatment values 3-16 weeks after transduction. Moreover, when normal mice were treated with an SV40-derived vector containing a modified human alpha1-AT complementary DNA engineered to be resistant to cleavage by the alpha1-AT ribozyme, they expressed human alpha1-AT messenger RNA and protein in their livers and serum levels of human alpha1-AT remained >1 microg/mL for 1 year. CONCLUSIONS: These results represent the initial steps toward a novel approach to the gene therapy of alpha1-AT deficiency.