Small molecule approach to differentiation of human induced pluripotent stem cells to sensory neurons

Abstract

In this study, we took an alternative approach and selected five small molecule inhibitors (SMIs) of key signaling pathways to test out a new protocol for the derivation of sensory neurons from human iPSCs. Within 8 days of the differentiation protocol, iPSC-derived sensory neurons were achieved at >80% efficiency. The derived cells were positive for cytoskeletal markers common to neurons, Tuj-1 and neurofilament, and specific markers for sensory neurons, Islet, peripherin and Brn3a. Whole-cell patch-clamp recordings of the neurons showed firing in response to membrane depolarization, capable of generating action potentials sensitive to tetrodotoxin. In co-culture with rat Schwann cells in myelinating medium, axon bundles of the derived sensory neurons underwent myelination, showing internodal segments that were positive for myelin basic protein. The phenotype of the iPSC-derived sensory neurons was sustainable in Neurobasal medium supplemented with maintenance growth factors but without SMIs. Our rapid and efficient induction protocol promises controlled production of sensory neurons from human iPSCs as a pool for developmental studies and disease modeling.