Development, Vol 107, Issue 3 453-463, Copyright © 1989 by Company of Biologists

JOURNAL ARTICLES

Another role for melanocytes: their importance for normal stria vascularis development in the mammalian inner ear

KP Steel and C Barkway
MRC Institute of Hearing Research, University of Nottingham, UK.

The stria vascularis of the mammalian cochlea is composed primarily of three types of cells. Marginal cells line the lumen of the cochlear duct and are of epithelial origin. Basal cells also form a continuous layer and they may be mesodermal or derived from the neural crest. Intermediate cells are melanocyte-like cells, presumably derived from the neural crest, and are scattered between the marginal and basal cell layers. The marginal cells form extensive interdigitations with the basal and intermediate cells in the normal adult stria. The stria also contains a rich supply of blood vessels. We investigated the role of melanocytes in the stria vascularis by studying its development in a mouse mutant, viable dominant spotting, which is known to have a primary neural crest defect leading to an absence of recognisable melanocytes in the skin. Melanocytes were not found in the stria of most of the mutants examined, and from about 6 days of age onwards a reduced amount of interdigitation amongst the cells of the stria was observed. These ultrastructural anomalies were associated with strial dysfunction. In the normal adult mammal, the stria produces an endocochlear potential (EP), a resting dc potential in the endolymph in the cochlear duct, which in mice is normally about +100 mV. In our control mice, EP rose to adult levels between 6 and 16 days after birth. In most of the mutants we studied, EP was close to zero at all ages from 6 to 20 days. Melanocyte-like cells appear to be vital for normal stria vascularis development and function. They may be necessary to facilitate the normal process of interdigitation between marginal and basal cell processes at a particular stage during development, and the lack of adequate interdigitation in the mutants may be the cause of their strial dysfunction. Alternatively, melanocytes may have some direct, essential role in the production of an EP by the stria. Melanocytes may be important both for normal strial development and for the production of the EP. We believe this is the clearest demonstration yet of a role for migratory melanocytes other than their role in pigmentation.

This article has been cited by other articles:

				K. Dutton, L. Abbas, J. Spencer, C. Brannon, C. Mowbray, M. Nikaido, R. N. Kelsh, and T. T. Whitfield A zebrafish model for Waardenburg syndrome type IV reveals diverse roles for Sox10 in the otic vesicle Dis. Model. Mech., January 1, 2009; 2(1-2): 68 - 83. [Abstract] [Full Text] [PDF]

				C. Goding and F. L. Meyskens Jr. Microphthalmic-Associated Transcription Factor Integrates Melanocyte Biology and Melanoma Progression Clin. Cancer Res., February 15, 2006; 12(4): 1069 - 1073. [Full Text] [PDF]

				L. Nie, W. Feng, R. Diaz, M. A. Gratton, K. J. Doyle, and E. N. Yamoah Functional Consequences of Polyamine Synthesis Inhibition by L-{alpha}-Difluoromethylornithine (DFMO): CELLULAR MECHANISMS FOR DFMO-MEDIATED OTOTOXICITY J. Biol. Chem., April 15, 2005; 280(15): 15097 - 15102. [Abstract] [Full Text] [PDF]

				K. P. Steel Varitint-waddler: A double whammy for hearing PNAS, November 12, 2002; 99(23): 14613 - 14615. [Full Text] [PDF]

				A. Forge and T. Wright The molecular architecture of the inner ear Br. Med. Bull., October 1, 2002; 63(1): 5 - 24. [Abstract] [Full Text] [PDF]

				C. C. Morton Genetics, genomics and gene discovery in the auditory system Hum. Mol. Genet., May 15, 2002; 11(10): 1229 - 1240. [Abstract] [Full Text] [PDF]

				D. C. Marcus, T. Wu, P. Wangemann, and P. Kofuji KCNJ10 (Kir4.1) potassium channel knockout abolishes endocochlear potential Am J Physiol Cell Physiol, February 1, 2002; 282(2): C403 - C407. [Abstract] [Full Text] [PDF]

				A. Rusch, L. Ng, R. Goodyear, D. Oliver, I. Lisoukov, B. Vennstrom, G. Richardson, M. W. Kelley, and D. Forrest Retardation of Cochlear Maturation and Impaired Hair Cell Function Caused by Deletion of All Known Thyroid Hormone Receptors J. Neurosci., December 15, 2001; 21(24): 9792 - 9800. [Abstract] [Full Text] [PDF]

				N. Bondurand, V. Pingault, D. E. Goerich, N. Lemort, E. Sock, C. L. Caignec, M. Wegner, and M. Goossens Interaction among SOX10, PAX3 and MITF, three genes altered in Waardenburg syndrome Hum. Mol. Genet., August 12, 2000; 9(13): 1907 - 1917. [Abstract] [Full Text] [PDF]

				C. R. Goding Mitf from neural crest to melanoma: signal transduction and transcription in the melanocyte lineage Genes & Dev., July 15, 2000; 14(14): 1712 - 1728. [Full Text]

				W Yang, C Li, D. Ward, J Kaplan, and S. Mansour Defective organellar membrane protein trafficking in Ap3b1-deficient cells J. Cell Sci., January 11, 2000; 113(22): 4077 - 4086. [Abstract] [PDF]

				H. Rhim, K. J. Dunn, A. Aronzon, S. Mac, M. Cheng, M. L. Lamoreux, S. M. Tilghman, and W. J. Pavan Spatially Restricted Hypopigmentation Associated with an Ednrbs-Modifying Locus on Mouse Chromosome 10 Genome Res., January 1, 2000; 10(1): 17 - 29. [Abstract] [Full Text]

				S. Takeuchi and M. Ando Voltage-dependent outward K+ current in intermediate cell of stria vascularis of gerbil cochlea Am J Physiol Cell Physiol, July 1, 1999; 277(1): C91 - C99. [Abstract] [Full Text] [PDF]

				A. Rusch, L. C. Erway, D. Oliver, B. Vennstrom, and D. Forrest Thyroid hormone receptor beta -dependent expression of a potassium conductance in inner hair cells at the onset of hearing PNAS, December 22, 1998; 95(26): 15758 - 15762. [Abstract] [Full Text] [PDF]

				S. Carreira, T. J. Dexter, U. Yavuzer, D. J. Easty, and C. R. Goding Brachyury-Related Transcription Factor Tbx2 and Repression of the Melanocyte-Specific TRP-1 Promoter Mol. Cell. Biol., September 1, 1998; 18(9): 5099 - 5108. [Abstract] [Full Text]

				L. Chin, J. Pomerantz, D. Polsky, M. Jacobson, C. Cohen, C. Cordon-Cardo, J. W. Horner II, and R. A. DePinho Cooperative effects of INK4a and ras in melanoma susceptibility in vivo Genes & Dev., November 1, 1997; 11(21): 2822 - 2834. [Abstract] [Full Text] [PDF]

				H. Hibino, Y. Horio, A. Inanobe, K. Doi, M. Ito, M. Yamada, T. Gotow, Y. Uchiyama, M. Kawamura, T. Kubo, et al. An ATP-Dependent Inwardly Rectifying Potassium Channel, KAB-2 (Kir4.1), in Cochlear Stria Vascularis of Inner Ear: Its Specific Subcellular Localization and Correlation with the Formation of Endocochlear Potential J. Neurosci., June 15, 1997; 17(12): 4711 - 4721. [Abstract] [Full Text] [PDF]

				K. Steel, D. Davidson, and I. Jackson TRP-2/DT, a new early melanoblast marker, shows that steel growth factor (c-kit ligand) is a survival factor Development, January 8, 1992; 115(4): 1111 - 1119. [Abstract] [PDF]