title: Long-term preservation of retinal function in the RCS rat model of retinitis pigmentosa following lentivirus-mediated gene therapy.
abstract: The Royal College of Surgeons (RCS) rat is a well-characterized model of autosomal recessive retinitis pigmentosa (RP) due to a defect in the retinal pigment epithelium (RPE). It is homozygous for a null mutation in the gene encoding , a receptor tyrosine kinase found in RPE cells, that is required for phagocytosis of shed photoreceptor outer segments. The absence of Mertk results in accumulation of outer segment debris. This subsequently leads to progressive loss of photoreceptor cells. In order to evaluate the efficacy of lentiviral-mediated gene replacement therapy in the RCS rat, we produced recombinant VSV-G pseudotyped HIV-1-based lentiviruses containing a murine Mertk cDNA driven by a spleen focus forming virus (SFFV) promoter. The vector was subretinally injected into the right eye of 10-day-old RCS rats; the left eye was left untreated as an internal control. Here, we present a detailed assessment of the duration and extent of the morphological rescue and the resulting functional benefits. We examined animals at various time points over a period of 7 months by light and electron microscopy, and electroretinography. We observed correction of the phagocytic defect, slowing of photoreceptor cell loss and preservation of retinal function for up to 7 months. This study demonstrates the potential of gene therapy approaches for the treatment of retinal degenerations caused by defects specific to the RPE and supports the use of lentiviral vectors for the treatment of such disorders.
authors.affiliation: Division of Molecular Therapy, Institute of Ophthalmology, University College London, UK.
authors.forename: M
authors.initials: M
authors.lastname: Tschernutter
authors.forename: F C
authors.initials: FC
authors.lastname: Schlichtenbrede
authors.forename: S
authors.initials: S
authors.lastname: Howe
authors.forename: K S
authors.initials: KS
authors.lastname: Balaggan
authors.forename: P M
authors.initials: PM
authors.lastname: Munro
authors.forename: J W B
authors.initials: JW
authors.lastname: Bainbridge
authors.forename: A J
authors.initials: AJ
authors.lastname: Thrasher
authors.forename: A J
authors.initials: AJ
authors.lastname: Smith
authors.forename: R R
authors.initials: RR
authors.lastname: Ali
mesh_terms: D000818:Animals; D004596:Electroretinography; D015316:Genetic Therapy / Q000379:methods*; D005822:Genetic Vectors / Q000008:administration & dosage*; D015497:HIV-1 / Q000235:genetics*; D006801:Humans; D007267:Injections; D008854:Microscopy, Electron; D023421:Models, Animal; D010786:Photoreceptor Cells / Q000473:pathology; D010857:Pigment Epithelium of Eye / Q000378:metabolism* / Q000503:physiopathology / Q000648:ultrastructure; D011401:Promoter Regions, Genetic; D011518:Proto-Oncogene Proteins / Q000235:genetics* / Q000378:metabolism; D051381:Rats; D011922:Rats, Mutant Strains; D020794:Receptor Protein-Tyrosine Kinases / Q000235:genetics* / Q000378:metabolism; D011993:Recombinant Fusion Proteins / Q000008:administration & dosage / Q000235:genetics; D012174:Retinitis Pigmentosa / Q000378:metabolism / Q000473:pathology / Q000628:therapy*; D013155:Spleen Focus-Forming Viruses / Q000235:genetics; D013997:Time Factors; D000076202:c-Mer Tyrosine Kinase
chemical_list: D011518:Proto-Oncogene Proteins; D011993:Recombinant Fusion Proteins; C097072:MERTK protein, human; D020794:Receptor Protein-Tyrosine Kinases; D000076202:c-Mer Tyrosine Kinase