title: Hair cell stereociliary bundle regeneration by espin gene transduction after aminoglycoside damage and hair cell induction by Notch inhibition.
abstract: Once inner ear hair cells (HCs) are damaged by drugs, noise or aging, their apical structures including the stereociliary arrays are frequently the first cellular feature to be lost. Although this can be followed by progressive loss of HC somata, a significant number of HC bodies often remain even after stereociliary loss. However, in the absence of stereocilia they are nonfunctional. HCs can sometimes be regenerated by Atoh1 transduction or Notch inhibition, but they also may lack stereociliary bundles. It is therefore important to develop methods for the regeneration of stereocilia, in order to achieve HC functional recovery. Espin is an actin-bundling protein known to participate in sterociliary elongation during development. We evaluated stereociliary array regeneration in damaged vestibular sensory epithelia in tissue culture, using viral vector transduction of two espin isoforms. Utricular HCs were damaged with aminoglycosides. The utricles were then treated with a γ-secretase inhibitor, followed by espin or control transduction and histochemistry. Although γ-secretase inhibition increased the number of HCs, few had stereociliary arrays. In contrast, 46 h after espin1 transduction, a significant increase in hair-bundle-like structures was observed. These were confirmed to be immature stereociliary arrays by scanning electron microscopy. Increased uptake of FM1-43 uptake provided evidence of stereociliary function. Espin4 transduction had no effect. The results demonstrate that espin1 gene therapy can restore stereocilia on damaged or regenerated HCs.
authors.affiliation: Department of Otolaryngology-Head and Neck Surgery, Graduate School of Medicine, Kyoto University, Kyoto, Japan.
authors.forename: A
authors.initials: A
authors.lastname: Taura
authors.affiliation: Department of Surgery, Graduate School of Medicine, Kyoto University, Kyoto, Japan.
authors.forename: K
authors.initials: K
authors.lastname: Taura
authors.affiliation: Department of Surgery, Graduate School of Medicine, Kyoto University, Kyoto, Japan.
authors.forename: Y
authors.initials: Y
authors.lastname: Koyama
authors.affiliation: Department of Otolaryngology-Head and Neck Surgery, Graduate School of Medicine, Kyoto University, Kyoto, Japan.
authors.forename: N
authors.initials: N
authors.lastname: Yamamoto
authors.affiliation: Department of Otolaryngology-Head and Neck Surgery, Graduate School of Medicine, Kyoto University, Kyoto, Japan.
authors.forename: T
authors.initials: T
authors.lastname: Nakagawa
authors.affiliation: Department of Otolaryngology-Head and Neck Surgery, Graduate School of Medicine, Kyoto University, Kyoto, Japan.
authors.forename: J
authors.initials: J
authors.lastname: Ito
authors.affiliation: Department of Otolaryngology-Head and Neck Surgery, Graduate School of Medicine, Kyoto University, Kyoto, Japan.|Divison of Otolaryngology, Department of Surgery, UCSD School of Medicine, La Jolla, CA, USA.|VA Medical Center, San Diego, CA, USA.|Department of Neurosciences, UCSD School of Medicine, La Jolla, CA, USA.
authors.forename: A F
authors.initials: AF
authors.lastname: Ryan
mesh_terms: D000617:Aminoglycosides / Q000633:toxicity; D053829:Amyloid Precursor Protein Secretases / Q000037:antagonists & inhibitors / Q000235:genetics; D000818:Animals; D003051:Cochlea / Q000187:drug effects / Q000473:pathology; D006199:Hair Cells, Auditory, Inner / Q000187:drug effects / Q000473:pathology / Q000648:ultrastructure*; D006801:Humans; D051379:Mice; D008840:Microfilament Proteins / Q000235:genetics* / Q000627:therapeutic use; D008855:Microscopy, Electron, Scanning; D011726:Pyridinium Compounds / Q000494:pharmacology; D000644:Quaternary Ammonium Compounds / Q000494:pharmacology; D051880:Receptors, Notch / Q000037:antagonists & inhibitors / Q000235:genetics*; D012038:Regeneration / Q000235:genetics*; D059547:Stereocilia / Q000235:genetics* / Q000473:pathology; D014161:Transduction, Genetic
chemical_list: D000617:Aminoglycosides; C493274:ESPN protein, human; C073804:FM1 43; D008840:Microfilament Proteins; D011726:Pyridinium Compounds; D000644:Quaternary Ammonium Compounds; D051880:Receptors, Notch; D053829:Amyloid Precursor Protein Secretases