Scientists are closer to curing blindness with the help of gene therapy
"Our goal is to create a methodology for personalized control of eye diseases. We still have a lot of work to do, but we believe that we can be the first to be able to adapt CRISPR for the treatment of congenital diseases. In this work, we have shown that this can be achieved in principle," said Stephen Tsang from Columbia University in New York (in a press release CRISPR Used to Repair Blindness–causing Genetic Defect in Patient-derived Stem Cells - VM).
Tsang and his colleagues have been working for several years to create a gene therapy aimed at treating retinitis pigmentosa, a hereditary disease that leads to the destruction of the retina of the eye, the death of photosensitive cells and blindness.
One of the most common forms of retinitis, affecting up to 90% of carriers of this disease, is caused by a single mutation in the RGPR gene (retinitis pigmentosa GTPase regulator – VM), in which there is a "typo" with a length of only one "letter"-a nucleotide.Tsang and his colleagues propose to combat this type of retinitis by growing stem cells, replacing the wrong version of RGPR in them, and turning them into cones and rods of the retina, which are then inserted into the patient's eye and replace the damaged photosensitive cells.
The authors of the article managed to implement the first step in this therapy – they successfully replaced the damaged RGPR gene, without causing damage to other genes surrounding this DNA fragment, and growing a culture of similar stem cells. It was quite difficult to do this, since RGPR contains a lot of repeating fragments that are present in other regions of the genome and to which CRISPR may react by mistake.
So far, scientists have not tried to turn them into cones, rods and other retinal cells, but they claim that it is quite simple to do this using the appropriate hormones and signaling molecules. In the near future, they will try to do this, and then transplant cells into the eyes of animals suffering from this form of retinitis, and also check whether CRISPR/Cas9 can be used to fix other mutations that cause retinal degeneration.
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28.01.2015