title: Canonical Notch signaling plays an instructive role in auditory supporting cell development.
abstract: The auditory sensory epithelium, composed of mechano-sensory hair cells (HCs) and highly specialized glial-like supporting cells (SCs), is critical for our ability to detect sound. SCs provide structural and functional support to HCs and play an essential role in cochlear development, homeostasis and repair. Despite their importance, however, surprisingly little is known about the molecular mechanisms guiding SC differentiation. 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 SCs. Using γ-secretase inhibitor DAPT to acutely block canonical Notch signaling, we identified a cohort of Notch-regulated SC-specific genes, with diverse functions in cell signaling, cell differentiation, neuronal innervation and synaptogenesis. We validated the newly identified Notch-regulated genes in vivo using genetic gain (Emx2(Cre/+); Rosa26(N1ICD/+)) and loss-of-function approaches (Emx2(Cre/+); Rosa26(DnMAML1/+)). Furthermore, we demonstrate that Notch over-activation in the differentiating murine cochlea (Emx2(Cre/+); Rosa26(N1ICD/+)) actively promotes a SC-specific gene expression program. Finally, we show that outer SCs -so called Deiters' cells are selectively lost by prolonged reduction (Emx2(Cre/+); Rosa26(DnMAML1/+/+)) or abolishment of canonical Notch signaling (Fgfr3-iCreER; Rbpj(-/Δ)), indicating a critical role for Notch signaling in Deiters' cell development.
authors.affiliation: Solomon H. Snyder Department of Neuroscience, Johns Hopkins University, School of Medicine Baltimore, MD 21205, USA.|Center for Sensory Biology, Johns Hopkins University, School of Medicine Baltimore, MD 21205, USA.
authors.forename: Dean P
authors.initials: DP
authors.lastname: Campbell
authors.affiliation: Solomon H. Snyder Department of Neuroscience, Johns Hopkins University, School of Medicine Baltimore, MD 21205, USA.|Center for Sensory Biology, Johns Hopkins University, School of Medicine Baltimore, MD 21205, USA.
authors.forename: Elena
authors.initials: E
authors.lastname: Chrysostomou
authors.affiliation: Solomon H. Snyder Department of Neuroscience, Johns Hopkins University, School of Medicine Baltimore, MD 21205, USA.|Center for Sensory Biology, Johns Hopkins University, School of Medicine Baltimore, MD 21205, USA.
authors.forename: Angelika
authors.initials: A
authors.lastname: Doetzlhofer
mesh_terms: D000818:Animals; D002452:Cell Count; D016923:Cell Death; D002454:Cell Differentiation / Q000235:genetics; D003051:Cochlea / Q000166:cytology / Q000196:embryology / Q000378:metabolism; D020869:Gene Expression Profiling; D018507:Gene Expression Regulation, Developmental; D007760:Labyrinth Supporting Cells / Q000166:cytology / Q000378:metabolism*; D051379:Mice; D008822:Mice, Transgenic; D009687:Nuclear Proteins / Q000235:genetics / Q000378:metabolism; D009928:Organ Specificity / Q000235:genetics; D010641:Phenotype; D051880:Receptors, Notch / Q000378:metabolism*; D015398:Signal Transduction; D014157:Transcription Factors / Q000235:genetics / Q000378:metabolism
chemical_list: C486455:Maml1 protein, mouse; D009687:Nuclear Proteins; D051880:Receptors, Notch; D014157:Transcription Factors