Reversal of Phenotypic Abnormalities by CRISPR/Cas9-Mediated Gene Correction in Huntington Disease Patient-Derived Induced Pluripotent Stem Cells

Huntington disease (HD) is a dominant neurodegenerative disorder caused by a CAG repeat expansion in HTT. Here we report correction of HD human induced pluripotent stem cells (hiPSCs) using a CRISPR-Cas9 and piggyBac transposon-based approach. We show that both HD and corrected isogenic hiPSCs can be differentiated into excitable, synaptically active forebrain neurons. We further demonstrate that phenotypic abnormalities in HD hiPSC-derived neural cells, including impaired neural rosette formation, increased susceptibility to growth factor withdrawal, and deficits in mitochondrial respiration, are rescued in isogenic controls. Importantly, using genome-wide expression analysis, we show that a number of apparent gene expression differences detected between HD and non-related healthy control lines are absent between HD and corrected lines, suggesting that these differences are likely related to genetic background rather than HD-specific effects. Our study demonstrates correction of HD hiPSCs and associated phenotypic abnormalities, and the importance of isogenic controls for disease modeling using hiPSCs. [Display omitted] •A CRISPR-Cas9 and PiggyBac-based approach allows efficient correction of HD hiPSCs•The corrected hiPSCs can be differentiated into synaptically active neurons•Correction of HD gene mutation reverses a number of phenotypic abnormalities•Isogenic hiPSCs help distinguish mutation from genetic background-related effects Pouladi and colleagues show that genetic correction of HD human induced pluripotent stem cells using a CRISPR-Cas9 and piggyBac transposon-based approach rescues a number of phenotypic abnormalities in derived neural cells, including increased susceptibility to growth factor withdrawal and deficits in mitochondrial respiration, and helps distinguish HD-specific from genetic background-related molecular and cellular phenotypes.