700. Stable Correction of Severe Metabolic Liver Disease Phenotypes in the Growing Murine Liver Using a Hybrid rAAV/piggyBac Transposon Gene Delivery System

摘要: Liver-targeted gene therapy using adeno-associated virus-based vectors (rAAV) shows therapeutic promise in animal models and adult-focused clinical trials. This promise, however, is not directly translatable to the growing liver where rapid clearance of rAAV episomal genomes occurs concert with hepatocellular proliferation. phenomenon has been shown underpin progressive loss efficacy, initially achieved neonatal period, mouse early-onset urea cycle defects (UCDs). We have developed a hybrid rAAV/piggyBac transposon vector system combining highly efficient liver-targeting properties stable piggyBac-mediated transposition transgene into hepatocyte genome. Transposition efficiency was first tested an EGFP expression cassette following delivery newborn wild-type mice, 20-fold increase stably gene-modified hepatocytes observed 4 weeks post-treatment compared traditional delivery. then modeled potential context severe early onset UCDs. A single treatment perinatal period sufficient confer robust phenotype correction ornithine transcarbamylase (OTC) deficient Spfash lethal argininosuccinate synthetase (ASS) knock-out mouse. The next utilized murine model chronic disease, familial intrahepatic cholestasis type 3 (PFIC3), which intervention prior disease necessary due development pathology impedes transduction. Stable persistent extending adulthood increased mean biliary phosphatidylcholine concentration dramatically reduced fibrosis. Finally, integration patterns were analysed, revealing 127,286 unique sites conformed previously published piggyBac data. Conclusion: Using we protection two UCD pathology. strategy for treating wide array inherited diseases onset. clinically conceivable application this technology management UCDs could be as bridging while awaiting transplantation. Further improvement will result from human liver-tropic capsids, use alternative strategies achieve transient transposase expression, engineered refinements safety profile transposase-mediated integration.