Notch Signaling Plays an Instructive Role in Supporting Cell Development and is Critical for Supporting Cell Survival

The sensory epithelium of the cochlea is a specialized structure responsible for the perception of sound. While much is understood about the development of the mechanosensory hair cells found within this epithelium, little is known about the development of the glial-like supporting cells. Here, we provide evidence that in addition to its well-characterized inhibitory function, canonical Notch signaling plays a positive, instructive role in the differentiation of supporting cells. Using γ-secretase inhibitor DAPT to acutely block canonical Notch signaling, we identified a cohort of Notch-regulated supporting cell-specific genes, with diverse functions in cell signaling, cell differentiation, neuronal innervation and synaptogenesis. RNA from cochlear epithelial cells was isolated from E15.5 cochlear explants after they have been cultured for 22 hours in the presence of gamma secretase inhibitor DAPT or vehicle control. A total of 6 samples was analyzed in three indepdent microarray experiments. For each microarray experiment there was one control sample and one DAPT treated sample.