The Journal of Neuroscience, March 1, 2002, 22(5):1718-1725
Downregulation of Otospiralin, a Novel Inner Ear Protein, Causes
Hair Cell Degeneration and Deafness
Benjamin
Delprat1, *,
Ana
Boulanger1, *,
Jing
Wang1,
Vicky
Beaudoin2,
Matthieu J.
Guitton1,
Stéphanie
Ventéo3,
Claude J.
Dechesne3,
Rémy
Pujol1,
Mireille
Lavigne-Rebillard1,
Jean-Luc
Puel1, and
Christian P.
Hamel1
1 Institut National de la Santé et de la
Recherche Médicale U. 254, Laboratoire de Neurobiologie de
l'Audition, 34090 Montpellier, France, 2 Département
de Chimie-Biologie, Université du Québec à
Trois-Rivières, Trois-Rivières (Québec), Canada, G9A
5H7, and 3 Institut National de la Santé et de la
Recherche Médicale U. 432, Neurobiologie et Développement
du Système Audiovestibulaire, Université Montpellier II,
34095 Montpellier cedex 05, France
Mesenchymal nonsensory regions of the inner ear are important
structures surrounding the neurosensory epithelium that are believed to
participate in the ionic homeostasis of the cochlea and vestibule. We
report here the discovery of otospiralin, an inner ear-specific protein
that is produced by fibrocytes from these regions, including the spiral
ligament and spiral limbus in the cochlea and the maculae and
semicircular canals in the vestibule. Otospiralin is a novel 6.4 kDa
protein of unknown function that shares a protein motif with the gag
p30 core shell nucleocapsid protein of type C retroviruses. To evaluate
its functional importance, we downregulated otospiralin by cochlear
perfusion of antisense oligonucleotides in guinea pigs. This led to a
rapid threshold elevation of the compound action potentials and
irreversible deafness. Cochlear examination by transmission electron
microscopy revealed hair cell loss and degeneration of the organ of
Corti. This demonstrates that otospiralin is essential for the survival
of the neurosensory epithelium.
Key words:
otospiralin; cochlea; vestibule; hair cell; deafness; gene; antisense; inner ear
*
B.D. and A.B. contributed equally to this work