title: Photoreceptor-targeted gene delivery using intravitreally administered AAV vectors in dogs.
abstract: Delivery of therapeutic transgenes to retinal photoreceptors using adeno-associated virus (AAV) vectors has traditionally required subretinal injection. Recently, photoreceptor transduction efficiency following intravitreal injection (IVT) has improved in rodent models through use of capsid-mutant AAV vectors; but remains limited in large animal models. Thickness of the inner limiting membrane (ILM) in large animals is thought to impair retinal penetration by AAV. Our study compared two newly developed AAV vectors containing multiple capsid amino acid substitutions following IVT in dogs. The ability of two promoter constructs to restrict reporter transgene expression to photoreceptors was also evaluated. AAV vectors containing the interphotoreceptor-binding protein (IRBP) promoter drove expression exclusively in rod and cone photoreceptors, with transduction efficiencies of ~4% of cones and 2% of rods. Notably, in the central region containing the cone-rich visual streak, 15.6% of cones were transduced. Significant regional variation existed, with lower transduction efficiencies in the temporal regions of all eyes. This variation did not correlate with ILM thickness. Vectors carrying a cone-specific promoter failed to transduce a quantifiable percentage of cone photoreceptors. The newly developed AAV vectors containing the IRBP promoter were capable of producing photoreceptor-specific transgene expression following IVT in the dog.
authors.affiliation: Small Animal Clinical Sciences, Michigan State University, East Lansing, MI, USA.
authors.forename: R F
authors.initials: RF
authors.lastname: Boyd
authors.affiliation: Diagnostic Center for Population and Animal Health, Michigan State University, East Lansing, MI, USA.
authors.forename: D G
authors.initials: DG
authors.lastname: Sledge
authors.affiliation: Department of Ophthalmology, University of Florida College of Medicine, Gainesville, FL, USA.
authors.forename: S L
authors.initials: SL
authors.lastname: Boye
authors.affiliation: Department of Ophthalmology, University of Florida College of Medicine, Gainesville, FL, USA.
authors.forename: S E
authors.initials: SE
authors.lastname: Boye
authors.affiliation: Department of Ophthalmology, University of Florida College of Medicine, Gainesville, FL, USA.
authors.forename: W W
authors.initials: WW
authors.lastname: Hauswirth
authors.affiliation: Small Animal Clinical Sciences, Michigan State University, East Lansing, MI, USA.
authors.forename: A M
authors.initials: AM
authors.lastname: Komáromy
authors.affiliation: Small Animal Clinical Sciences, Michigan State University, East Lansing, MI, USA.
authors.forename: S M
authors.initials: SM
authors.lastname: Petersen-Jones
authors.affiliation: Small Animal Clinical Sciences, Michigan State University, East Lansing, MI, USA.
authors.forename: J T
authors.initials: JT
authors.lastname: Bartoe
mesh_terms: D000818:Animals; D000229:Dependovirus / Q000235:genetics*; D004285:Dogs; D004742:Enhancer Elements, Genetic; D005136:Eye Proteins / Q000235:genetics / Q000378:metabolism; D018014:Gene Transfer Techniques; D005822:Genetic Vectors / Q000235:genetics / Q000378:metabolism; D049452:Green Fluorescent Proteins / Q000235:genetics; D058449:Intravitreal Injections; D020419:Photoreceptor Cells, Vertebrate / Q000378:metabolism*; D011401:Promoter Regions, Genetic; D012160:Retina / Q000378:metabolism; D014161:Transduction, Genetic
chemical_list: D005136:Eye Proteins; D049452:Green Fluorescent Proteins