[en] During the development of the mammalian inner ear, the number of hair cells produced is highly regulated and remains constant throughout life. The mechanism underlying this regulation is beginning to be understood although many aspects still remain obscure. When late embryonic or early postnatal rat organs of Corti were cultured, the production of supernumerary hair cells was observed. This overproduction of sensory cells could be modulated by the addition of several growth factors. In this study, we examined explants of rat organs of Corti that produced supernumerary hair cells. In the supernumerary hair cell region, up to two rows of inner hair cells and five rows of outer hair cells were observed. Morphological evaluation of these specimens revealed that less mature hair cells were located in the most external rows of these sensory cells. When a supernumerary hair cell was produced, a supporting cell (i.e. Deiters' cell) was also produced, strongly suggesting that the conversion of a Deiters' cell into a hair cell was not the mechanism that produced these extra hair cells. Based on these results, we propose that prosensory cells located at the external edge of the organ of Corti retain a capacity to form hair cells and that it is these prosensory cells that differentiate into supernumerary hair cells and Deiters' cells.
Ruben, R.J., Development of the inner ear of the mouse: A radioautographic study of terminal mitoses (1967) Acta Otolaryngol (Stockh), 220 (SUPPL.), pp. 1-44
Chen, P., Segil, N., p27(Kip1) links cell proliferation to morphogenesis in the developing organ of Corti (1999) Development, 126, pp. 1581-1590
Abdouh, A., Despres, G., Romand, R., Hair cell overproduction in the developing mammalian cochlea in culture (1993) Neuroreport, 5, pp. 33-36
Chardin, S., Romand, R., Factors modulating supernumerary hair cell production in the postnatal rat cochlea in vitro (1997) Int J Dev Neurosci, 15, pp. 497-507
Romand, R., Chardin, S., Le Calvez, S., The spontaneous appearance of hair cell-like cells in the mammalian cochlea following aminoglycoside ototoxicity (1996) Neuroreport, 8, pp. 133-137
Lefebvre, P.P., Malgrange, B., Thiry, M., Van de Water, T.R., Moonen, G., Epidermal growth factor upregulates production of supernumerary hair cells in neonatal rat organ of Corti (2000) Acta Otolaryngol (Stockh), 120, pp. 142-145. , Ref Type: Generic
Kelley, M.W., Xu, X.M., Wagner, M.A., Warchol, M.E., Corwin, J.T., The developing organ of Corti contains retinoic acid and forms supernumerary hair cells in response to exogenous retinoic acid in culture (1993) Development, 119, pp. 1041-1053
Adam, J., Myat, A., Le Roux, I., Eddison, M., Henrique, D., Ish-Horowicz, D., Lewis, J., Cell fate choices and the expression of Notch, Delta and Serrate homologues in the chick inner ear: Parallels with Drosophila sense-organ development (1998) Development, 125, pp. 4645-4654
Haddon, C., Jiang, Y.J., Smithers, L., Lewis, J., Delta-Notch signalling and the patterning of sensory cell differentiation in the zebra fish ear: Evidence from the mind bomb mutant (1998) Development, 125, pp. 4637-4644
Lanford, P.J., Lan, Y., Jiang, R., Lindsell, C., Weinmaster, G., Gridley, T., Kelley, M.W., Notch signalling pathway mediates hair cell development in mammalian cochlea (1999) Nat Genet, 21, pp. 289-292
Zine, A., Van de Water, T.R., De Ribaupierre, F., Notch signaling regulates the pattern of auditory hair cell differentiation in mammals (2000) Development, 127, pp. 3373-3383. , Ref Type: Generic
Romand, R., Zine, A.E., Hafidi, A., Ontogenesis of F-actin in hair cells (1993) Cell Motil Cytoskeleton, 25, pp. 213-222
Zine, A., Romand, R., Development of the auditory receptors of the rat: A SEM study (1996) Brain Res, 721, pp. 49-58
Zheng, J.L., Gao, W.Q., Overexpression of math1 induces robust production of extra hair cells in postnatal rat inner ears (2000) Nat Neurosci, 3, pp. 580-586
Zine, A., De Ribaupierre, F., Replacement of mammalian auditory hair cells (1998) Neuroreport, 9, pp. 263-268
Lefebvre, P.P., Malgrange, B., Staecker, H., Moonen, G., Van de Water, T.R., Retinoic acid stimulates regeneration of mammalian auditory hair cells (1993) Science, 260, pp. 692-695
Kelley, M.W., Talreja, D.R., Corwin, J.T., Replacement of hair cells after laser microbeam irradiation in cultured organs of corti from embryonic and neonatal mice (1995) J Neurosci, 15, pp. 3013-3026