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EMBO Mol Med. 2019 Jan;11(1). pii: e9396. doi: 10.15252/emmm.201809396.

A dual-AAV approach restores fast exocytosis and partially rescues auditory function in deaf otoferlin knock-out mice.

Author information

1
Molecular Biology of Cochlear Neurotransmission Group, Department of Otorhinolaryngology, University Medical Center Göttingen, and Collaborative Research Center 889, University of Göttingen, Göttingen, Germany.
2
Göttingen Graduate School for Neurosciences, Biophysics, and Molecular Biosciences, University of Göttingen, Göttingen, Germany.
3
Institute for Auditory Neurosciences and InnerEarLab, University Medical Center Göttingen, Göttingen, Germany.
4
Synaptic Nanophysiology Group, Max Planck Institute for Biophysical Chemistry, Göttingen, Germany.
5
Center Nanoscale Microscopy and Physiology of the Brain (CNMPB), Department of Neurology, University Medical Center Göttingen, Göttingen, Germany sebastian.kuegler@med.uni-goettingen.de ellen.reisinger@med.uni-goettingen.de.
6
Molecular Biology of Cochlear Neurotransmission Group, Department of Otorhinolaryngology, University Medical Center Göttingen, and Collaborative Research Center 889, University of Göttingen, Göttingen, Germany sebastian.kuegler@med.uni-goettingen.de ellen.reisinger@med.uni-goettingen.de.

Abstract

Normal hearing and synaptic transmission at afferent auditory inner hair cell (IHC) synapses require otoferlin. Deafness DFNB9, caused by mutations in the OTOF gene encoding otoferlin, might be treated by transferring wild-type otoferlin cDNA into IHCs, which is difficult due to the large size of this transgene. In this study, we generated two adeno-associated viruses (AAVs), each containing half of the otoferlin cDNA Co-injecting these dual-AAV2/6 half-vectors into the cochleae of 6- to 7-day-old otoferlin knock-out (Otof -/-) mice led to the expression of full-length otoferlin in up to 50% of IHCs. In the cochlea, otoferlin was selectively expressed in auditory hair cells. Dual-AAV transduction of Otof -/- IHCs fully restored fast exocytosis, while otoferlin-dependent vesicle replenishment reached 35-50% of wild-type levels. The loss of 40% of synaptic ribbons in these IHCs could not be prevented, indicating a role of otoferlin in early synapse maturation. Acoustic clicks evoked auditory brainstem responses with thresholds of 40-60 dB. Therefore, we propose that gene delivery mediated by dual-AAV vectors might be suitable to treat deafness forms caused by mutations in large genes such as OTOF.

KEYWORDS:

deafness; gene therapy; hearing restoration; inner ear; inner hair cell

Comment in

PMID:
30509897
PMCID:
PMC6328916
DOI:
10.15252/emmm.201809396
[Indexed for MEDLINE]
Free PMC Article

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