Differentiation of human embryonic stem cells toward cells with otic characteristics

Abstract

Mechanosensory hair cells are central for our senses of hearing and balance. They are located in the auditory and vestibular organs of the inner ear. In mammals, these cells do not regenerate and hair cell loss, which happens after noise insults, drug side effects, or the effects of genetic disposition or aging, leads to permanent hearing loss and balance disorders. My host laboratory's previously shown that mouse embryonic stem cells (mESCs) can be differentiated toward sensory hair cells in vitro; however the same protocol was not effective with human embryonic stem cells (hESCs). Here we show that application of repressive and inductive signals involved in early embryonic development followed by application of other factors involved in inner ear induction directs hESC differentiation into progenitor cells that express multiple otic marker genes. We subjected these otic progenitors to varying differentiation conditions, one of which promoted the organization of the cells into epithelial clusters displaying hair cell-like cells with stereociliary bundles. HESC-derived hair cell-like cells display apical protrusions that immunolabeled with hair bundle markers. In summary, we show that the universal mechanisms involved in early development of the human inner ear can be recapitulated in vitro, which enables the design of new strategies for cell replacement therapies, drug discoveries and developmental studies.