Gene therapy restores vision and delays degeneration in the CNGB1(-/-) mouse model of retinitis pigmentosa.
Retinitis pigmentosa (RP) is a group of genetically heterogeneous, severe retinal diseases commonly leading to legal blindness. Mutations in the CNGB1a subunit of the rod cyclic nucleotide-gated (CNG) channel have been found to cause RP in patients. Here, we demonstrate the efficacy of gene therapy as a potential treatment for RP by means of recombinant adeno-associated viral (AAV) vectors in the CNGB1 knockout (CNGB1(-/-)) mouse model. To enable efficient packaging and rod-specific expression of the relatively large CNGB1a cDNA (~4 kb), we used an AAV expression cassette with a short rod-specific promoter and short regulatory elements. After injection of therapeutic AAVs into the subretinal space of 2-week-old CNGB1(-/-) mice, we assessed the restoration of the visual system by analyzing (i) CNG channel expression and localization, (ii) retinal function and morphology and (iii) vision-guided behavior. We found that the treatment not only led to expression of full-length CNGB1a, but also restored normal levels of the previously degraded CNGA1 subunit of the rod CNG channel. Both proteins co-localized in rod outer segments and formed regular CNG channel complexes within the treated area of the CNGB1(-/-) retina, leading to significant morphological preservation and a delay of retinal degeneration. In the electroretinographic analysis, we also observed restoration of rod-driven light responses. Finally, treated CNGB1(-/-) mice performed significantly better than untreated mice in a rod-dependent vision-guided behavior test. In summary, this work provides a proof-of-concept for the treatment of rod channelopathy-associated RP by AAV-mediated gene replacement.
Center for Integrated Protein Science Munich, Department of Pharmacy - Center for Drug Research, Ludwig-Maximilians-Universität München, Butenandtstr. 5-13, 81377 Munich, Germany.
Susanne
S
Koch
Vithiyanjali
V
Sothilingam
Marina
M
Garcia Garrido
Naoyuki
N
Tanimoto
Elvir
E
Becirovic
Fred
F
Koch
Christina
C
Seide
Susanne C
SC
Beck
Mathias W
MW
Seeliger
Martin
M
Biel
Regine
R
Mühlfriedel
Stylianos
S
Michalakis
D000818:Animals; D054815:Cyclic Nucleotide-Gated Cation Channels / Q000235:genetics* / Q000378:metabolism; D018076:DNA, Complementary / Q000235:genetics / Q000378:metabolism; D000229:Dependovirus / Q000235:genetics / Q000378:metabolism; D004195:Disease Models, Animal; D004596:Electroretinography; D015316:Genetic Therapy; D005822:Genetic Vectors / Q000235:genetics / Q000378:metabolism; D051379:Mice; D018345:Mice, Knockout; D009419:Nerve Tissue Proteins / Q000235:genetics* / Q000378:metabolism; D012162:Retinal Degeneration / Q000235:genetics / Q000628:therapy; D012174:Retinitis Pigmentosa / Q000235:genetics* / Q000378:metabolism / Q000628:therapy*; D012243:Rhodopsin / Q000235:genetics / Q000378:metabolism; D012374:Rod Cell Outer Segment / Q000378:metabolism
C529481:Cngb1 protein, mouse; D054815:Cyclic Nucleotide-Gated Cation Channels; D018076:DNA, Complementary; D009419:Nerve Tissue Proteins; D012243:Rhodopsin