A new gene therapy approach to treat retinitis pigmentosa (RP) has been discovered by researchers from Trinity College Dublin and University College London (UCL).
The first direct-to-human gene therapy to treat RP (Luxturna), delivers the correct version of the mutated RPE65 gene to the retina. However RPE65 is one of more than 260 genes that may be responsible for RP. Another is the gene RP2, which is responsible for making a protein essential for normal vision.
The research team used a modified common virus to deliver a normal, functioning copy of the RP2 gene into ‘mini retinas’, which had been engineered from stem cells and which contained the defective version of the gene to simulate the RP2 disease in patients.
Subsequent analysis showed the mini retinas had successfully taken up the functioning RP2 gene following viral delivery and produced the essential protein associated with it.
Crucially, the treated mini retinas showed significant improvement – underlining that the approach had rescued them from RP.
While still some time and work away from an approved therapy, Professor Michael Cheetham from UCL said, “It is an important development that we can now reproduce so many elements of inherited disease using these mini-retinas. It makes it possible for us to study, in detail, why people go blind and try to find ways to prevent blindness. It’s exciting that the gene therapy seems to be so effective for this form of RP.”
The study was published in Stem Cell Reports.
Lane et al., Modeling and Rescue of RP2 Retinitis Pigmentosa Using iPSC-Derived Retinal Organoids, Stem Cell Reports (2020), https://doi.org/10.1016/j.stemcr.2020.05.007