Optimization of Retinal Gene Therapy for X-Linked Retinitis Pigmentosa Due to RPGR Mutations

• Type of Material: Article
• Authors: John Alexander, Emory University; William A. Beltran, University of Pennsylvania; Artur V. Cideciyan, University of Pennsylvania; Shannon E. Boye, University of Florida; Guo-Jie Ye, Applied Genetic Technologies Corporation; Simone Iwabe, University of Pennsylvania; Valerie L. Dufour, University of Pennsylvania; Luis Felipe Marinho, University of Pennsylvania; Malgorzata Swider, University of Pennsylvania; Mychajlo S. Kosyk, University of Pennsylvania; Jin Sha, University of Pennsylvania; Sanford L. Boye, University of Florida; James J. Peterson, University of Florida; C. Douglas Witherspoon, University of Alabama Birmingham; Gui-Shuang Ying, University of Pennsylvania; Mark S. Shearman, Applied Genetic Technologies Corporation; Jeffrey D. Chulay, Applied Genetic Technologies Corporation; William W. Hauswirth, University of Florida; Paul D. Gamlin, University of Alabama Birmingham; Samuel G. Jacobson, University of Pennsylvania; Gustavo D. Aguirre, University of Pennsylvania
• Language: English
• Date: 2017-08-02
• Publisher: Elsevier (Cell Press): 12 month embargo
• Publication Version: Final Published Version
• Copyright Statement: © 2017 The American Society of Gene and Cell Therapy
• License: Creative Commons Attribution-NoDerivs 4.0 International
• Final Published Version (URL): http://dx.doi.org/10.1016/j.ymthe.2017.05.004
• Title of Journal or Parent Work: Molecular Therapy
• ISSN: 1525-0016
• Volume: 25
• Issue: 8
• Start Page: 1866
• End Page: 1880
• Grant/Funding Information: This work was supported primarily by NEI/NIH (R24EY-022012, R01EY017549, R01EY06855, R01EY013203, R01EY024280, P30EY-001583, and P30EY-003039) and AGTC (Alachua, FL, USA).; Additional support provided by the Foundation Fighting Blindness, Macula Vision Research Foundation, Hope for Vision, Van Sloun fund for canine genetic research, and Research to Prevent Blindness.
• Keywords: RHODOPSIN KINASE PROMOTER; Genetics & Heredity; Biotechnology & Applied Microbiology; Life Sciences & Biomedicine; PROTEIN; PRIMATE RETINA; Medicine, Research & Experimental; DEGENERATION; PHOTORECEPTOR; Science & Technology; Research & Experimental Medicine; DISEASE; EXON ORF15 MUTATIONS; AAV VECTOR; ADENOASSOCIATED VIRAL VECTORS; EXPRESSION
• Research Categories: Health Sciences, Opthamology; Health Sciences, Medicine and Surgery

Abstract

X-linked retinitis pigmentosa (XLRP) caused by mutations in the RPGR gene is an early onset and severe cause of blindness. Successful proof-of-concept studies in a canine model have recently shown that development of a corrective gene therapy for RPGR-XLRP may now be an attainable goal. In preparation for a future clinical trial, we have here optimized the therapeutic AAV vector construct by showing that GRK1 (rather than IRBP) is a more efficient promoter for targeting gene expression to both rods and cones in non-human primates. Two transgenes were used in RPGR mutant (XLPRA2) dogs under the control of the GRK1 promoter. First was the previously developed stabilized human RPGR (hRPGRstb). Second was a new full-length stabilized and codon-optimized human RPGR (hRPGRco). Long-term (>2 years) studies with an AAV2/5 vector carrying hRPGRstb under control of the GRK1 promoter showed rescue of rods and cones from degeneration and retention of vision. Shorter term (3 months) studies demonstrated comparable preservation of photoreceptors in canine eyes treated with an AAV2/5 vector carrying either transgene under the control of the GRK1 promoter. These results provide the critical molecular components (GRK1 promoter, hRPGRco transgene) to now construct a therapeutic viral vector optimized for RPGR-XLRP patients.