Human
skeletal muscle stem cells were generated from facioscapulohumeral
muscular dystrophy (FSHD) and
healthy control iPSC using a
transgene-free
skeletal muscle differentiation protocol and production of stable iMyoblasts. Analyses revealed that FSHD and
healthy control iMyoblasts are embryonic-like myogenic cells that undergo myotube differentiation
ex vivo by
growth factor depletion and are efficiently transplantable into the tibialis anterior (TA) muscles of NSG mice, where
human muscle under-goes embryonic-to-adult
myosin isoform switching. The DUX4 FSHD
disease gene maintains its hypomethylated
disease state inFSHD iPSC and iMyoblast, and its expression is upregulated during myotube differentiation and in
muscle xenografts. Consequently, these iMyoblasts accurately exhibit the
molecular pathology of human muscular dystrophies and are useful for the development of
drug,
gene editing and
stem cell therapeutics.