Abstract
The treatment of dominantly inherited retinal diseases requires silencing of the pathogenic allele. RNA interference to suppress gene expression suffers from wide-spread off-target effects, while CRISPR-mediated gene disruption creates permanent changes in the genome. CRISPR interference uses a catalytically inactive ‘dead’ Cas9 directed by a guide RNA to block transcription of chosen genes without disrupting the DNA. It is highly specific and potentially reversible, increasing its safety profile as a therapy. Pre-clinical studies have demonstrated the versatility of CRISPR interference for gene silencing both in vivo and in ex vivo modification of iPSCs for transplantation. Applying CRISPR interference techniques for the treatment of autosomal dominant inherited retinal diseases is promising but there are few in vivo studies to date. This review details how CRISPR interference might be used to treat retinal diseases and addresses potential challenges for clinical translation.
Highlights
Inherited retinal diseases are an irreversible and devastating cause of blindness for an estimated2 million individuals worldwide [1]
While CRISPRi can be highly efficient for some targets, with one paper reporting a 1000-fold repression of the mRNA target, it is generally accepted that the active cutting form of CRISPR/Cas9 is more efficient at knocking down target gene expression than CRISPRi [15,27,32]
This might be due to the different mechanisms between CRISPR/Cas9 and CRISPRi: CRISPR/Cas9 may be able to cleave DNA whilst in contact with it only briefly, which might be the case with mismatched nucleotides, whereas for CRISPRi to be effective, it is likely to need to be in contact with the DNA target for considerably longer
Summary
The eye has several advantages as a gene therapy site It is accessible using ophthalmic surgical techniques allowing direct delivery to the target organ using local anaesthesia; it is immune privileged which reduces the likelihood of immune responses or rejection, and the presence of the blood retina barrier helps to prevent systemic spread of the introduced material [3–5]. The bacteria contain two specialized RNA molecules called crRNA and tracrRNA, which form a complex with the endonuclease protein Cas. The bacteria contain two specialized RNA molecules called crRNA and tracrRNA, which form a complex with the endonuclease protein Cas9 This complex is guided to viral DNA that share sequence homology. Sci. 2020, 21, 2329 which form a complex with the endonuclease protein Cas9 This complex guided to viral DNA that share sequence homology with crRNA. CRISPRi with dCas to block transcription initiation or transcriptional elongation. (d) CRISPRi using a dCas9-KRAB fusion protein to alter the chromatin state of the gene
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
