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Preclinical Dose-Escalation Study of Intravitreal AAV-RS1 Gene Therapy in a Mouse Model of X-linked Retinoschisis : Dose-Dependent Expression and Improved Retinal Structure and Function

Bush, Ronald A; Zeng, Yong; Colosi, Peter; Kjellström, Sten LU ; Hiriyanna, Suja; Vijayasarathy, Camasamudram; Santos, Maria; Li, Jinbo; Wu, Zhijian and Sieving, Paul A (2016) In Human Gene Therapy 27(5). p.376-389
Abstract

Gene therapy for inherited retinal diseases has been shown to ameliorate functional and structural defects in both animal models and in human clinical trials. X-linked retinoschisis (XLRS) is an early-age onset macular dystrophy resulting from loss of an extracellular matrix protein (RS1). In preparation for a human clinical gene therapy trial, we conducted a dose-range efficacy study of the clinical vector, a self-complementary AAV delivering a human retinoschisin (RS1) gene under control of the RS1 promoter and an interphotoreceptor binding protein enhancer (AAV8-scRS/IRBPhRS), in the retinoschisin knockout (Rs1-KO) mouse. The therapeutic vector at 1 × 10(6) to 2.5 × 10(9) (1E6-2.5E9) vector genomes (vg)/eye or vehicle was... (More)

Gene therapy for inherited retinal diseases has been shown to ameliorate functional and structural defects in both animal models and in human clinical trials. X-linked retinoschisis (XLRS) is an early-age onset macular dystrophy resulting from loss of an extracellular matrix protein (RS1). In preparation for a human clinical gene therapy trial, we conducted a dose-range efficacy study of the clinical vector, a self-complementary AAV delivering a human retinoschisin (RS1) gene under control of the RS1 promoter and an interphotoreceptor binding protein enhancer (AAV8-scRS/IRBPhRS), in the retinoschisin knockout (Rs1-KO) mouse. The therapeutic vector at 1 × 10(6) to 2.5 × 10(9) (1E6-2.5E9) vector genomes (vg)/eye or vehicle was administered to one eye of 229 male Rs1-KO mice by intravitreal injection at 22 ± 3 days postnatal age (PN). Analysis of retinal function (dark-adapted electroretinogram, ERG), structure (cavities and outer nuclear layer thickness) by in vivo retinal imaging using optical coherence tomography, and retinal immunohistochemistry (IHC) for RS1 was done 3-4 months and/or 6-9 months postinjection (PI). RS1 IHC staining was dose dependent across doses ≥1E7 vg/eye, and the threshold for significant improvement in all measures of retinal structure and function was 1E8 vg/eye. Higher doses, however, did not produce additional improvement. At all doses showing efficacy, RS1 staining in Rs1-KO mouse was less than that in wild-type mice. Improvement in the ERG and RS1 staining was unchanged or greater at 6-9 months than at 3-4 months PI. This study demonstrates that vitreal administration of AAV8 scRS/IRBPhRS produces significant improvement in retinal structure and function in the mouse model of XLRS over a vector dose range that can be extended to a human trial. It indicates that a fully normal level of RS1 expression is not necessary for a therapeutic effect.

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author
organization
publishing date
type
Contribution to journal
publication status
published
subject
in
Human Gene Therapy
volume
27
issue
5
pages
14 pages
publisher
Mary Ann Liebert, Inc.
external identifiers
  • wos:000374649600006
  • scopus:84964749484
ISSN
1043-0342
DOI
10.1089/hum.2015.142
language
English
LU publication?
yes
id
2dbb2978-e611-4834-98ef-06d962c8b28a
date added to LUP
2016-04-27 12:37:14
date last changed
2017-05-21 04:50:13
@article{2dbb2978-e611-4834-98ef-06d962c8b28a,
  abstract     = {<p>Gene therapy for inherited retinal diseases has been shown to ameliorate functional and structural defects in both animal models and in human clinical trials. X-linked retinoschisis (XLRS) is an early-age onset macular dystrophy resulting from loss of an extracellular matrix protein (RS1). In preparation for a human clinical gene therapy trial, we conducted a dose-range efficacy study of the clinical vector, a self-complementary AAV delivering a human retinoschisin (RS1) gene under control of the RS1 promoter and an interphotoreceptor binding protein enhancer (AAV8-scRS/IRBPhRS), in the retinoschisin knockout (Rs1-KO) mouse. The therapeutic vector at 1 × 10(6) to 2.5 × 10(9) (1E6-2.5E9) vector genomes (vg)/eye or vehicle was administered to one eye of 229 male Rs1-KO mice by intravitreal injection at 22 ± 3 days postnatal age (PN). Analysis of retinal function (dark-adapted electroretinogram, ERG), structure (cavities and outer nuclear layer thickness) by in vivo retinal imaging using optical coherence tomography, and retinal immunohistochemistry (IHC) for RS1 was done 3-4 months and/or 6-9 months postinjection (PI). RS1 IHC staining was dose dependent across doses ≥1E7 vg/eye, and the threshold for significant improvement in all measures of retinal structure and function was 1E8 vg/eye. Higher doses, however, did not produce additional improvement. At all doses showing efficacy, RS1 staining in Rs1-KO mouse was less than that in wild-type mice. Improvement in the ERG and RS1 staining was unchanged or greater at 6-9 months than at 3-4 months PI. This study demonstrates that vitreal administration of AAV8 scRS/IRBPhRS produces significant improvement in retinal structure and function in the mouse model of XLRS over a vector dose range that can be extended to a human trial. It indicates that a fully normal level of RS1 expression is not necessary for a therapeutic effect.</p>},
  author       = {Bush, Ronald A and Zeng, Yong and Colosi, Peter and Kjellström, Sten and Hiriyanna, Suja and Vijayasarathy, Camasamudram and Santos, Maria and Li, Jinbo and Wu, Zhijian and Sieving, Paul A},
  issn         = {1043-0342},
  language     = {eng},
  number       = {5},
  pages        = {376--389},
  publisher    = {Mary Ann Liebert, Inc.},
  series       = {Human Gene Therapy},
  title        = {Preclinical Dose-Escalation Study of Intravitreal AAV-RS1 Gene Therapy in a Mouse Model of X-linked Retinoschisis : Dose-Dependent Expression and Improved Retinal Structure and Function},
  url          = {http://dx.doi.org/10.1089/hum.2015.142},
  volume       = {27},
  year         = {2016},
}