Loss of function of Ywhah in mice induces deafness and cochlear outer hair cells' degeneration

L. Bruet (1) , G Rebillard (1) , E. Brun (1) , Claire Angebault (1) , M. Pequignot (1) , M. Lenoir (1) , M Do-Cruzeiro (2) , E Tournier (2) , K. Kornille (1) , A Saleur (1) , N. Gueguen (3) , P. Reynier (3, 4) , P. Amati-Bonneau (3) , A. Barakat (5) , Christophe Blanchet (6) , P. Chinnery (7) , P Yu-Wai-Man (7) , J. Kaplan (8, 9) , A.F. Roux (6) , G van Camp (10) , B. Wissinger (11) , O. Boespflug-Tanguy (12) , F. Giraudet (13) , J-L Puel (1) , Guy Lenaers (1) , C Hamel (1, 6) , Benjamin Delprat (1) , C. Delettre (1)

1 INM - Institut des Neurosciences de Montpellier
2 PRHTEC - Plateforme Recombinaison Homologue, Transfert d'Embryons et Cryoconservation [Institut Cochin]
3 Service d'ophtalmologie [Angers]
4 MITOVASC - MitoVasc - Physiopathologie Cardiovasculaire et Mitochondriale
5 Institut Pasteur du Maroc
6 CHRU Montpellier - Centre Hospitalier Régional Universitaire [Montpellier]
7 Newcastle University [Newcastle]
8 Equipe Inserm U1163 - Genetics in Ophthalmology
9 Hôpital Necker - Enfants Malades [AP-HP]
10 UA - University of Antwerp
11 Eberhard Karls Universität Tübingen = Eberhard Karls University of Tuebingen
12 AP-HP Hôpital universitaire Robert-Debré [Paris]
13 Neuro-Dol - Neuro-Dol

In vertebrates, 14-3-3 proteins form a family of seven highly conserved isoforms with chaperone activity, which bind phosphorylated substrates mostly involved in regulatory and checkpoint pathways. 14-3-3 proteins are the most abundant protein in the brain and are abundantly found in the cerebrospinal fluid in neurodegenerative diseases, suggesting a critical role in neuron physiology and death. Here we show that 14-3-3eta-deficient mice displayed auditory impairment accompanied by cochlear hair cells' degeneration. We show that 14-3-3eta is highly expressed in the outer and inner hair cells, spiral ganglion neurons of cochlea and retinal ganglion cells. Screening of YWHAH, the gene encoding the 14-3-3eta isoform, in non-syndromic and syndromic deafness, revealed seven non-synonymous variants never reported before. Among them, two were predicted to be damaging in families with syndromic deafness. In vitro, variants of YWHAH induce mild mitochondrial fragmentation and severe susceptibility to apoptosis, in agreement with a reduced capacity of mutated 14-3-3eta to bind the pro-apoptotic Bad protein. This study demonstrates that YWHAH variants can have a substantial effect on 14-3-3eta function and that 14-3-3eta could be a critical factor in the survival of outer hair cells.

Domaines: Médecine humaine et pathologie; Organisation et fonctions cellulaires [q-bio.SC]

L. Bruet, G Rebillard, E. Brun, Claire Angebault, M. Pequignot, et al.. Loss of function of Ywhah in mice induces deafness and cochlear outer hair cells' degeneration. Cell Death Discovery, 2016, 2 (1), pp.16017. ⟨10.1038/cddiscovery.2016.17⟩. ⟨hal-01866772⟩