Adeno-Associated Viral (AAV) Vector-Mediated Gene Therapy for X-linked Retinitis Pigmentosa (XLRP): A Long-Term Efficacy Study in Mouse Models of RPGR or RP2 Deficiency

Monday, September 22, 2014 — Poster Session II
4:00 p.m. – 6:00 p.m.	FAES Academic Center	NEI	GEN-8

* FARE Award Winner

Authors

• S Mookherjee
• P Colosi
• S Hiriyanna
• K Kaneshiro
• H Qian
• M Campos
• C Gao
• R Fariss
• H Khanna
• T Li
• A Swaroop
• Z Wu

Abstract

X-Linked retinitis pigmentosa (XLRP) represents a severe form of retinitis pigmentosa characterized by a progressive loss of photoreceptor cells, leading to blindness. Mutations in RPGR and RP2 genes account for ~90% of XLRP cases, with no treatment available. Most of the mutations in these genes are loss- of-function and therefore are amenable to gene replacement therapy. To develop a treatment, we designed and generated AAV vectors carrying human RPGR or RP2 cDNA and employed appropriate gene regulatory elements along with AAV serotype to ensure photoreceptor specific transgene expression. These vectors were tested in Rpgr or Rp2 null mouse models for XLRP. Electroretinography (ERG), Optical Coherence Tomography (OCT) and Optomotor test, were used to follow the efficacy of the treatment. Rpgr null mice receiving 1e9 vector genome with RPGR shows improved day and night visual function along with corrected retinal histology. Similarly, Rp2 null mice treated with RP2 AAV vector showed improved daylight vision and visual acuity along with corrected retinal histology. In conclusion, our study represents the first comprehensive and successful pre-clinical dose-efficacy study for the treatment of XLRP and paves the way for future clinical trials in patients.

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