Project 06
Prevention of premature photoreceptor cell death in CRB1 retinitis pigmentosa models by RNA modulation.
Recombinant adeno-associated viral vector-mediated gene therapy for RP and LCA has a great potential of preventing retinal disease.
Recombinant adeno-associated viral (AAV) vector-mediated gene therapy for RP and LCA has a great potential of preventing retinal disease, as demonstrated with the development and commercialization of FDA-approved LUXTURNA for patients with mutations in the RPE65 gene. LUXTURNA targets the retinal pigment epithelium and infection/transduction of all of the RPE cells is more efficient than infection/transduction of all of the photoreceptors in the retina. The inefficient transduction of photoreceptor cells causes a mosaic pattern of non-transduced adjacent to transduced diseased photoreceptor cells, and the non-transduced cells will further undergo cell death (potentially affecting the neighboring cells and leading to failure of gene therapy). In order to prevent such premature cell death it would be helpful to nurture the target cells with growth factors such as the rod-derived cone viability factor to protect cones, or other growth factors to nurture rods, RPE cells or Müller glial cells. Mutations in the CRB1 gene are a frequent cause of early-onset RP or LCA in children.
The aim of this project is to demonstrate neuroprotection by RNA aptamers to improve rAAV gene augmentation therapies targeting photoreceptors such as but not limited to rAAV CRB gene augmentation.
Approach
We will explore the action of various RNA aptamers on CRB1 patient iPSC-derived retinal organoids, Crb1 mouse models, and CRB2 knockout iPSC-derived RPE and Crb2 mouse models. The RNA aptamers will be TrkB-aptamer developed by partner DC3 and newly developed agonistic RNA aptamers for Basigin-1, the receptor for RdCVF, and other neuroprotective growth factor receptors. We will develop rAAV mammalian autocatalytic circular RNA expression vectors for validated RNA aptamers, and apply these in combination therapy with AAV-CRB onto our various CRB1 and CRB2 models for retinitis pigmentosa. The DC will be trained in complex cell culture techniques as well as in vivo retinal biology including hiPSC-retinal organoids, hiPSC- RPE, retina-on-a-chip, rAAV and/or high-capacity adenoviral vector technology, and mouse experiments such as electroretinograpy, spatial frequency and contrast sensitivity optic kinetic head tracking, and in vivo imaging techniques such as spectral domain optical coherence tomography and confocal scanning laser ophthalmoscopy.
Expected results
- Assessment of the expression of neuroprotective growth factors in healthy and CRB-mutant models (human organoids or mouse retinas)
- Development of new RNA-aptamers for such growth factors and generation of RNA-expression vectors
- Analysis of activated signaling pathways upon successful expression of RNA-aptamers
- Phenotypic rescue of retinal degeneration in CRB models upon RNA-aptamer expression
Planned secondments
- B7, supervisor: Aileen Murphy
Purpose: economic training - B3, supervisor: Sven Schnichels
Purpose: Tornado system for expressing RNA aptamers - AP7, supervisor: Beatriz Llamusí
Purpose: business training