Investigation of the use of cellular gene promoters in murine retroviral vectors

• Main Author: Schwickerath, Oliver
• Published: University College London (University of London) 2007
• Subjects: 572.8
• Online Access: http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.503104

This study investigates the use of cellular promoters in the context of an enhancer-deleted murine retroviral vector suitable for application in gene therapy protocols for treating diseases that affect the myeloid lineage (Schwickerath et al., 2004). Although the theory and practice surrounding enhancer-deleted and self-inactivating vectors has been known for some time, only recently have their attributes been considered to be of primary importance. Our model system for the development of gene therapy has been chronic granulomatous disease/disorder (CGD), an inherited condition affecting the ability of neutrophils to kill invading pathogens, with potentially fatal consequences. The disease is caused by mutations in any one of several components referred to as gp91'"' p6 p4 " ' or p22'""'A which together with rac2 make up the NADPH oxidase complex present in neutrophils and other phagocytes (Casimir and Teahan, 1994 Goldblatt and Thrasher, 2000 Seger and Kzekowitz, 1994 Thrasher et al., 1992 Thrasher et al., 1993 Thrasher et al., 1994). This project aimed to improve the transcriptional output and safety of retroviral vectors in myeloid cells, the cell type affected in CGD and to identify suitable tissue specific and inducible promoters for myeloid specific gene expression, which were employed for the expression of p47 (Rodaway et al., 1990 Teahan et al., 1990), the major cause of the autosomal recessive form of the disease. To prove the functionality of our constructs in vivo, we made use of a p47 "N deficient mouse as a disease model for CGD, which lacks phagocyte superoxide production, thus reflecting an identical phenotype to that seen in human CGD (Jackson et al., 1995 Messina et al., 2002 Mitchison et al., 2005). We conclude to have developed an enhancer-deleted retroviral vector that could provide the basis for a new generation of retroviral vectors with improved safety, by essentially retaining high titre and demonstrated transcriptional activity in myeloid cells, capable of reconstituting very high levels of oxidase activity, comparable to that obtained from normal cells.