Combined small-molecule inhibition accelerates developmental timing and converts human pluripotent stem cells into nociceptors

Chambers et al. use a combination of small-molecule pathway inhibitors to rapidly differentiate human pluripotent stem cells into nociceptors, a type of sensory neuron. The conversion occurs about three-fold faster than during development, suggesting that pathway inhibition may offer a general approach for speeding up the generation of specific cell types in vitro. Considerable progress has been made in identifying signaling pathways that direct the differentiation of human pluripotent stem cells (hPSCs) into specialized cell types, including neurons. However, differentiation of hPSCs with extrinsic factors is a slow, step-wise process, mimicking the protracted timing of human development. Using a small-molecule screen, we identified a combination of five small-molecule pathway inhibitors that yield hPSC-derived neurons at >75% efficiency within 10 d of differentiation. The resulting neurons express canonical markers and functional properties of human nociceptors, including tetrodotoxin (TTX)-resistant, SCN10A-dependent sodium currents and response to nociceptive stimuli such as ATP and capsaicin. Neuronal fate acquisition occurs about threefold faster than during in vivo development1, suggesting that use of small-molecule pathway inhibitors could become a general strategy for accelerating developmental timing in vitro. The quick and high-efficiency derivation of nociceptors offers unprecedented access to this medically relevant cell type for studies of human pain.