Poster Presentation 39th Annual Lorne Genome Conference 2018

Development and optimization of an efficient method for CRISPR/Cas correction of patient-specific iPSCs (#272)

Qi Wang 1 , Kristof Wing 1 , Alice Pébay 2 3 , Anthony Cook 4 , Alex Hewitt 1 2 3
  1. Menzies Institute for Medical Research, University of Tasmania, Hobart, Tasmania, Australia
  2. Centre for Eye Research Australia, University of Melbourne, Royal Victorian Eye and Ear Hospital, Melbourne, Victoria, Australia
  3. Department of Ophthalmology, University of Melbourne, Melbourne, Victoria, Australia
  4. Wicking Dementia Research & Education Centre, University of Tasmania, Hobart, Tasmania, Australia

Patient specific induced pluripotent stem cells (iPSCs) can be differentiated into any cell type of the body and harbour disease-specific genetic profiles, making them an ideal platform for modelling inherited diseases. Although combining iPSCs with CRISPR/Cas technology has been championed as attractive strategy in the development of gene-based therapies, given the low frequency of homology directed repair (HDR) pathway, the generation of isogenic gene-corrected iPSCs is generally laborious. Here we report the optimization of a high throughput CRISPR/Cas correction of patient-specific iPSCs. We nucleofect a fluorescent-labelled sgRNA with high fidelity form of Cas9 as a CRISPR ribonucleoprotein (RNP) along with an asymmetric repair donor to target the mutation site of iPSCs. Post-electroporation, the cells are cultured with L755507 for 48h to enhance the HDR efficiency, then rather than manually picking single clones, Fluorescence Assisted Cell Sorting (FACS) is used to seed individual cells into vitronectin coated 96-well plates. Following adaptation to CloneR supplement and a plate centrifuge process, we observed a final single cell viability of at least 50% on feeder-free culture. Screening of single cell clones is initially performed with PCR amplification and single nucleotide polymorphism (SNP) genotyping. Clones are finally screened via bi-directional sanger sequencing. Using this approach, isogenic corrected patient-specific iPSCs can be generated within 5 weeks for a cost of approximately $AUD 3000. The combination of these optimizations has allowed the development of a rapid, easy, and efficient means for gene correction in iPSCs.