Large-scale expansion of human iPSC-derived skeletal muscle cells for disease modeling and cell-based therapeutic strategies

Although skeletal muscle cells can be generated from human iPSCs, transgene-free protocols include only limited options for their purification and expansion. In this study we found that FACS-purified myogenic progenitors generated from healthy controls and Pompe disease iPSCs can be robustly expanded as much as 5 x 1011 fold. At all steps during expansion, cells could be cryopreserved or differentiated into myotubes with a high fusion index. In vitro, cells were amenable to maturation into striated and contractile myofibers. Insertion of the acid alpha glucosidase cDNA into the AAVS1 locus in iPSCs using CRISPR/cas9 prevented glycogen accumulation in myotubes generated from a patient with classic infantile Pompe disease. In vivo, the expression of human-specific nuclear and sarcolemmar antigens indicated that myogenic progenitors engraft into murine muscle to form human myofibers. This protocol is useful for modeling of skeletal muscle disorders and for using patient-derived, gene-corrected cells to develop cell-based strategies. Overall design: Myogenic progenitors were expanded for ~15 days and harvested either in proliferation conditions or after 4 days of differentiation as described previously (van der Wal et al., 2017b). RNA was extracted using the RNeasy minikit with DNAse treatment (Qiagen, Germantown, MD). Sequencing libraries were prepared using TruSeq Stranded mRNA Library Prep Kit (Illumina, San Diego, California, USA) according to the manufacturer's instructions. Libraries were sequenced on a HiSeq2500 sequencer (Illumina, San Diego, California, USA) in rapid-run mode according to the manufacturer's instructions. Reads 50 base-pairs in length were generated. The RNA-sequencing datasets listed in table S3 were downloaded and aligned with the datasets generated in this study using the 'new Tuxedo' pipeline (Pertea et al., 2016). The processed data file includes the analysis of 30 additonal Samples from other research groups, partly from GEO and partly from other sources such as ENCODE and ENA. The header table linked below lists the origin of the other Samples.

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van der Wal E, Herrero-Hernandez P, Wan R, Broeders M, In 't Groen SLM, van Gestel TJM, van IJcken WFJ, Cheung TH, van der Ploeg AT, Schaaf GJ, Pijnappel WWMP