Virally expressed connexin26 restores gap junction function in the cochlea of conditional Gjb2 knockout mice.
Mutations in GJB2, which codes for the gap junction (GJ) protein connexin26 (Cx26), are the most common causes of human nonsyndromic hereditary deafness. We inoculated modified adeno-associated viral (AAV) vectors into the scala media of early postnatal conditional Gjb2 knockout mice to drive exogenous Cx26 expression. We found extensive virally expressed Cx26 in cells lining the scala media, and intercellular GJ network was re-established in the organ of Corti of mutant mouse cochlea. Widespread ectopic Cx26 expression neither formed ectopic GJs nor affected normal hearing thresholds in wild-type (WT) mice, suggesting that autonomous cellular mechanisms regulate proper membrane trafficking of exogenously expressed Cx26 and govern the functional manifestation of them. Functional recovery of GJ-mediated coupling among the supporting cells was observed. We found that both cell death in the organ of Corti and degeneration of spiral ganglion neurons in the cochlea of mutant mice were substantially reduced, although auditory brainstem responses did not show significant hearing improvement. This is the first report demonstrating that virally mediated gene therapy restored extensive GJ intercellular network among cochlear non-sensory cells in vivo. Such a treatment performed at early postnatal stages resulted in a partial rescue of disease phenotypes in the cochlea of the mutant mice.
1] Department of Otolaryngology Head & Neck Surgery, Beijing Tongren Hospital, Capital Medical University, Beijing, China [2] Department of Otolaryngology, Emory University School of Medicine, Atlanta, GA, USA.
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Yu
Department of Otolaryngology, Eye & ENT Hospital, Fudan University, Shanghai, China.
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Y
Wang
Department of Otolaryngology, Emory University School of Medicine, Atlanta, GA, USA.
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Chang
Department of Otolaryngology, Emory University School of Medicine, Atlanta, GA, USA.
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J
Wang
Department of Otolaryngology Head & Neck Surgery, Beijing Tongren Hospital, Capital Medical University, Beijing, China.
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S
Gong
Department of Otolaryngology, Eye & ENT Hospital, Fudan University, Shanghai, China.
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H
Li
Department of Otolaryngology, Emory University School of Medicine, Atlanta, GA, USA.
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Lin
D000818:Animals; D000831:Animals, Newborn; D003053:Cochlear Duct / Q000378:metabolism*; D000072259:Connexin 26; D017630:Connexins / Q000235:genetics* / Q000378:metabolism; D003638:Deafness / Q000235:genetics / Q000473:pathology* / Q000628:therapy*; D000229:Dependovirus / Q000235:genetics* / Q000378:metabolism; D004195:Disease Models, Animal; D017629:Gap Junctions / Q000502:physiology*; D015316:Genetic Therapy; D005822:Genetic Vectors; D006801:Humans; D051379:Mice; D008810:Mice, Inbred C57BL; D018345:Mice, Knockout; D009925:Organ of Corti / Q000378:metabolism*; D021381:Protein Transport
D017630:Connexins; C000607042:GJB2 protein, human; C000607043:Gjb2 protein, mouse; D000072259:Connexin 26