title: Phenotypic correction of a mouse model of hemophilia A using AAV2 vectors encoding the heavy and light chains of FVIII.
abstract: Using separate adeno-associated viral 2 (AAV2) vectors to deliver the heavy and light chains of factor VIII (FVIII) we have overcome the packaging limitations of AAV, achieving phenotypic correction of hemophilia A in mice. AAV vectors were constructed that use a liver-specific promoter and the cDNA sequences of either the human or canine heavy and light chains of FVIII. After intraportal vein injection of these vectors in hemophilia-A mice, therapeutic to superphysiologic levels of active FVIII were achieved in plasma in a dose-dependent manner. Phenotypic correction of the bleeding diathesis was demonstrated by survival of all treated mice after tail clipping. Biochemical analysis demonstrated lower levels of heavy-chain (25- to 100-fold) compared with light-chain protein in the plasma of treated animals. Differences in gene transfer and transcription did not account for the differences in protein expression. We hypothesize that improvements in FVIII activity could be achieved by improvements in FVIII heavy-chain expression. This work demonstrates that cotransduction of liver with AAV vectors expressing the heavy and light chains of FVIII corrects hemophilia A in vivo, providing an alternative approach to the use of a single vector. This strategy may potentially be useful for other large therapeutic proteins that contain functionally distinct domains.
authors.affiliation: Avigen, Inc, 1201 Harbor Bay Parkway, Alameda, CA 94502, USA.
authors.forename: Ciaran D
authors.initials: CD
authors.lastname: Scallan
authors.forename: Tongyao
authors.initials: T
authors.lastname: Liu
authors.forename: Amy E
authors.initials: AE
authors.lastname: Parker
authors.forename: Susannah L
authors.initials: SL
authors.lastname: Patarroyo-White
authors.forename: Haifeng
authors.initials: H
authors.lastname: Chen
authors.forename: Haiyan
authors.initials: H
authors.lastname: Jiang
authors.forename: Joseph
authors.initials: J
authors.lastname: Vargas
authors.forename: Dea
authors.initials: D
authors.lastname: Nagy
authors.forename: Sharon K
authors.initials: SK
authors.lastname: Powell
authors.forename: J Fraser
authors.initials: JF
authors.lastname: Wright
authors.forename: Rita
authors.initials: R
authors.lastname: Sarkar
authors.forename: Haig H
authors.initials: HH
authors.lastname: Kazazian
authors.forename: Alan
authors.initials: A
authors.lastname: McClelland
authors.forename: Linda B
authors.initials: LB
authors.lastname: Couto
mesh_terms: D000256:Adenoviridae / Q000235:genetics; D000818:Animals; D004195:Disease Models, Animal; D004285:Dogs; D005169:Factor VIII / Q000008:administration & dosage* / Q000032:analysis / Q000235:genetics; D015316:Genetic Therapy / Q000379:methods*; D005822:Genetic Vectors / Q000008:administration & dosage*; D006467:Hemophilia A / Q000628:therapy*; D006470:Hemorrhage / Q000517:prevention & control; D006801:Humans; D008099:Liver / Q000378:metabolism; D051379:Mice; D018345:Mice, Knockout; D010641:Phenotype; D011169:Portal Vein; D011401:Promoter Regions, Genetic; D021122:Protein Subunits / Q000008:administration & dosage* / Q000097:blood / Q000235:genetics; D019076:Transgenes; D016896:Treatment Outcome
chemical_list: D021122:Protein Subunits; D005169:Factor VIII