Helper-dependent adenoviral vectors in the treatment of citrullinemia

Document Type

Conference Paper


Emergency Medicine


Citrullinemia is a urea cycle disorder characterized by deficiency of argininosuccinate synthetase (ASS). Gene therapy correction in both humans and animal models will require high levels of hepatocyte transduction and long-term transgene expression. To achieve these objectives, we have generated helper-dependent adenoviral vectors devoid of viral coding genes which express human ASS (hASS) from a ubiquitously active elongation factor 1 (BOS) promoter (Ad?BOShASS). Evaluation of Ad?BOShASS by Southern analysis, real-time quantitative PCR, and fluorescent in situ hybridization (FISH) after intravenous injection into C57BL/6 mice show helper virus contamination of ˂ 1%, stable vector structure, and efficient hepatocyte transduction. Northern analysis using a transgene-specific probe showed mRNA expression levels in liver comparable to wild type murine ASS. Our previous data suggested that use of liver-specific and endogenous genomic promoters may increase transgene expression and blunt the host immune response. We analysed mice at 3 days and 8 weeks after injection with first generation adenoviral vectors expressing hASS from either the ubiquitously expressing CAG promoter or the liver-specific albumin promoter. hASS mRNA expression persisted in mice treated with the albumin promoter vector compared to the CAG promoter virus. These data have prompted us to evaluate helper-dependent vectors containing the endogenous ASS and alpha-1-antitrypsin promoters driving human ASS minigenes for treatment of bovine and human citrullinemia.


This work was published before the author joined Aga Khan University.

Publication ( Name of Journal)

Journal of Inherited Metabolic Disease