Accelerated high-yield generation of limb-innervating motor neurons from human stem cells

Human pluripotent stem cells are a promising source of diverse cells for developmental studies, cell transplantation, disease modeling, and drug testing. However, their widespread use even for intensely studied cell types like spinal motor neurons, is hindered by the long duration and low yields of existing protocols for in vitro differentiation and by the molecular heterogeneity of the populations generated. We report a combination of small molecules that induce up to 50% motor neurons within 3 weeks from human pluripotent stem cells with defined subtype identities that are relevant to neurodegenerative diseases. Despite their accelerated differentiation, motor neurons expressed combinations of HB9, ISL1 and column-specific markers that mirror those observed in vivo in human fetal spinal cord. They also exhibited spontaneous and induced activity, and projected axons towards muscles when grafted into developing chick spinal cord. Strikingly, this novel protocol preferentially generates motor neurons expressing markers of limb-innervating lateral motor column motor neurons (FOXP1+/LHX3-). Access to high-yield cultures of human limb-innervating motor neuron subtypes will facilitate in-depth study of motor neuron subtype-specific properties, disease modeling, and development of large-scale cell-based screening assays. Overall design: We analyzed 3 samples including 2 positive samples and 1 negative sample. Descriptions are as follows: a) Positive Sample 1: SHH-derived, day 21 GFP-high FACS-purified motor neurons. b) Positive Sample 2: S+P-derived, day 21 GFP-high FACS-purified motor neurons. c) Negative: S+P condition, day 21 GFP-off FACS-purified non-motor neurons. Initial analysis of data was performed on ~40% of fastq reads (Amoroso et al., J Neurosci 2013 Jan 9;33(2):574-86. PMID: 23303937). Further processing of the full dataset has since been carried out and the updated rpkm file and expression analysis reflecting all aligned reads can be accessed at: http://scholar.harvard.edu/amorosornaseq/

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Amoroso MW, Croft GF, Williams DJ, O'Keeffe S, Carrasco MA, Davis AR, Roybon L, Oakley DH, Maniatis T, Henderson CE, Wichterle H