CRISPR-Cas9-mediated gene editing in human MPS I fibroblasts.

Abstract Mucopolysaccharidosis type I (MPS I) is a lysosomal storage disorder (LSD). It is caused by mutations in the IDUA gene, which lead to the accumulation of the glycosaminoglycans dermatan and heparan sulfate. The CRISPR-Cas9 system is a new and powerful tool that allows gene editing at precise points of the genome, resulting in gene correction through the introduction and genomic integration of a wildtype sequence. In this study, we used the CRISPR-Cas9 genome editing technology to correct in vitro the most common mutation causing MPS I. Human fibroblasts homozygous for p.Trp402* (legacy name W402X) were transfected and analyzed for up to one month after treatment. IDUA activity was significantly increased, lysosomal mass was decreased, and next generation sequencing confirmed that a percentage of cells carried the wildtype sequence. As a proof of concept, this study demonstrates that CRISPR-Cas9 genome editing may be used to correct causative mutations in MPS I. List of abbreviations Unlabelled Table CRISPR Clustered Regularly Interspaced Short Palindromic Repeats Cas CRISPR-associated ERT enzyme replacement therapy HDR homology-directed repair HSCT hematopoietic stem cell transplantation IDUA alpha-L-iduronidase LSD lysosomal storage disorder MPS I Mucopolysaccharidosis type I Highlights • MPS I human fibroblasts were corrected with CRISPR-Cas9 gene editing. • MPS I cells presented higher enzyme activity and recovery of phenotype. • Gene editing can be used for lysosomal storage disorders. [ABSTRACT FROM AUTHOR]