Clustered Regularly Interspaced Short Palindromic Repeats-Based Genome Surgery for the Treatment of Autosomal Dominant Retinitis Pigmentosa

Ophthalmology. 2018 Sep;125(9):1421-1430. doi: 10.1016/j.ophtha.2018.04.001. Epub 2018 May 11.


Purpose: To develop a universal gene therapy to overcome the genetic heterogeneity in retinitis pigmentosa (RP) resulting from mutations in rhodopsin (RHO).

Design: Experimental study for a combination gene therapy that uses both gene ablation and gene replacement.

Participants: This study included 2 kinds of human RHO mutation knock-in mouse models: RhoP23H and RhoD190N. In total, 23 RhoP23H/P23H, 43 RhoP23H/+, and 31 RhoD190N/+ mice were used for analysis.

Methods: This study involved gene therapy using dual adeno-associated viruses (AAVs) that (1) destroy expression of the endogenous Rho gene in a mutation-independent manner via an improved clustered regularly interspaced short palindromic repeats-based gene deletion and (2) enable expression of wild-type protein via exogenous cDNA.

Main outcome measures: Electroretinographic and histologic analysis.

Results: The thickness of the outer nuclear layer (ONL) after the subretinal injection of combination ablate-and-replace gene therapy was approximately 17% to 36% more than the ONL thickness resulting from gene replacement-only therapy at 3 months after AAV injection. Furthermore, electroretinography results demonstrated that the a and b waves of both RhoP23H and RhoD190N disease models were preserved more significantly using ablate-and-replace gene therapy (P < 0.001), but not by gene replacement monotherapy.

Conclusions: As a proof of concept, our results suggest that the ablate-and-replace strategy can ameliorate disease progression as measured by photoreceptor structure and function for both of the human mutation knock-in models. These results demonstrate the potency of the ablate-and-replace strategy to treat RP caused by different Rho mutations. Furthermore, because ablate-and-replace treatment is mutation independent, this strategy may be used to treat a wide array of dominant diseases in ophthalmology and other fields. Clinical trials using ablate-and-replace gene therapy would allow researchers to determine if this strategy provides any benefits for patients with diseases of interest.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Clustered Regularly Interspaced Short Palindromic Repeats
  • Disease Models, Animal
  • Electroretinography
  • Genetic Therapy / methods*
  • Genetic Vectors
  • Mice
  • Mice, Inbred C57BL
  • Mice, Knockout
  • Retinitis Pigmentosa / diagnosis
  • Retinitis Pigmentosa / genetics*
  • Retinitis Pigmentosa / therapy