title: A microRNA-regulated and GP64-pseudotyped lentiviral vector mediates stable expression of FVIII in a murine model of Hemophilia A.
abstract: The objective to use gene therapy to provide sustained, therapeutic levels of factor VIII (FVIII) for hemophilia A is compromised by the emergence of inhibitory antibodies that prevent FVIII from performing its essential function as a cofactor for factor IX (FIX). FVIII appears to be more immunogenic than FIX and an immune response is associated more frequently with FVIII than FIX gene therapy strategies. We have evaluated a modified lentiviral delivery strategy that facilitates liver-restricted transgene expression and prevents off-target expression in hematopoietic cells by incorporating microRNA (miRNA) target sequences. In contrast to outcomes using this strategy to deliver FIX, this modified delivery strategy was in and of itself insufficient to prevent an anti-FVIII immune response in treated hemophilia A mice. However, pseudotyping the lentivirus with the GP64 envelope glycoprotein, in conjunction with a liver-restricted promoter and a miRNA-regulated FVIII transgene resulted in sustained, therapeutic levels of FVIII. These modifications to the lentiviral delivery system effectively restricted FVIII transgene expression to the liver. Plasma levels of FVIII could be increased to around 9% that of normal levels when macrophages were depleted prior to treating the hemophilia A mice with the modified lentiviral FVIII delivery system.
authors.affiliation: Department of Pathology and Molecular Medicine, Queen's University, Kingston, Ontario, Canada.
authors.forename: Hideto
authors.initials: H
authors.lastname: Matsui
authors.forename: Carol
authors.initials: C
authors.lastname: Hegadorn
authors.forename: Margareth
authors.initials: M
authors.lastname: Ozelo
authors.forename: Erin
authors.initials: E
authors.lastname: Burnett
authors.forename: Angie
authors.initials: A
authors.lastname: Tuttle
authors.forename: Andrea
authors.initials: A
authors.lastname: Labelle
authors.forename: Paul B
authors.initials: PB
authors.lastname: McCray
authors.forename: Luigi
authors.initials: L
authors.lastname: Naldini
authors.forename: Brian
authors.initials: B
authors.lastname: Brown
authors.forename: Christine
authors.initials: C
authors.lastname: Hough
authors.forename: David
authors.initials: D
authors.lastname: Lillicrap
mesh_terms: D000818:Animals; D004195:Disease Models, Animal; D005169:Factor VIII / Q000235:genetics / Q000378:metabolism*; D015316:Genetic Therapy / Q000379:methods; D006467:Hemophilia A / Q000628:therapy*; D016086:Lentivirus / Q000235:genetics*; D051379:Mice; D008810:Mice, Inbred C57BL; D035683:MicroRNAs / Q000235:genetics*
chemical_list: D035683:MicroRNAs; D005169:Factor VIII