Gene Editing using CRISPR/Cas9 for Gene Correction in Recessive Dystrophic Epidermolysis Bullosa (RDEB) (360G-Wellcome-211890_Z_18_Z)

Conventional gene therapy approaches rely on the addition of a corrected gene copy via viral vector transduction. Such strategies are currently being applied to recessive dystrophic epidermolysis bullosa (RDEB) where there is defective collagen type VII protein. However, use of constitutive exogenous promoters in viral vectors results in sustained gene expression that is not subject to the normal regulatory mechanisms of C7 expression. Integrating properties of vectors also pose risk for insertional mutagenic-derived events and efficiency of gene transfer has been challenging given the large size of COL7A1 cDNA. Whereas, gene-editing tools can be designed and engineered to target and repair specific defined regions of DNA, thereby alleviating genomic toxicity and maintaining endogenous gene expression control. Existence of well-known mutation hotspots within COL7A1 allows CRISPR reagents to be designed that would target the mutations found in the UK population with RDEB. Investigations outlined in this proposal aim to identify the most effective CRISPR reagent for a chosen mutation hotspot within COL7A1 gene. In skin, keratinocytes predominantly produce collagen type VII. Therefore, this project will evaluate feasibility of gene editing approaches using CRISPR/Cas9 system in HACAT keratinocytes cell line, and help address critical aspects of CRISPR/Cas9 efficiency at a chosen loci.