title: Hair cell replacement in adult mouse utricles after targeted ablation of hair cells with diphtheria toxin.
abstract: We developed a transgenic mouse to permit conditional and selective ablation of hair cells in the adult mouse utricle by inserting the human diphtheria toxin receptor (DTR) gene into the Pou4f3 gene, which encodes a hair cell-specific transcription factor. In adult wild-type mice, administration of diphtheria toxin (DT) caused no significant hair cell loss. In adult Pou4f3(+/DTR) mice, DT treatment reduced hair cell numbers to 6% of normal by 14 days post-DT. Remaining hair cells were located primarily in the lateral extrastriola. Over time, hair cell numbers increased in these regions, reaching 17% of untreated Pou4f3(+/DTR) mice by 60 days post-DT. Replacement hair cells were morphologically distinct, with multiple cytoplasmic processes, and displayed evidence for active mechanotransduction channels and synapses characteristic of type II hair cells. Three lines of evidence suggest replacement hair cells were derived via direct (nonmitotic) transdifferentiation of supporting cells: new hair cells did not incorporate BrdU, supporting cells upregulated the pro-hair cell gene Atoh1, and supporting cell numbers decreased over time. This study introduces a new method for efficient conditional hair cell ablation in adult mouse utricles and demonstrates that hair cells are spontaneously regenerated in vivo in regions where there may be ongoing hair cell turnover.
authors.affiliation: The Virginia Merrill Bloedel Hearing Research Center and the Department of Otolaryngology-Head and Neck Surgery, University of Washington, Seattle, Washington 98195, USA.
authors.forename: Justin S
authors.initials: JS
authors.lastname: Golub
authors.forename: Ling
authors.initials: L
authors.lastname: Tong
authors.forename: Tot B
authors.initials: TB
authors.lastname: Ngyuen
authors.forename: Cliff R
authors.initials: CR
authors.lastname: Hume
authors.forename: Richard D
authors.initials: RD
authors.lastname: Palmiter
authors.forename: Edwin W
authors.initials: EW
authors.lastname: Rubel
authors.forename: Jennifer S
authors.initials: JS
authors.lastname: Stone
mesh_terms: D000704:Analysis of Variance; D000818:Animals; D051792:Basic Helix-Loop-Helix Proteins / Q000235:genetics; D001973:Bromodeoxyuridine / Q000378:metabolism; D002452:Cell Count / Q000379:methods; D004167:Diphtheria Toxin / Q000633:toxicity*; D004305:Dose-Response Relationship, Drug; D004848:Epithelium / Q000187:drug effects / Q000378:metabolism; D005786:Gene Expression Regulation / Q000187:drug effects; D049452:Green Fluorescent Proteins / Q000235:genetics; D018069:Hair Cells, Vestibular / Q000187:drug effects*; D066257:Heparin-binding EGF-like Growth Factor; D018398:Homeodomain Proteins / Q000235:genetics / Q000378:metabolism; D006801:Humans; D036341:Intercellular Signaling Peptides and Proteins / Q000235:genetics; D051379:Mice; D008810:Mice, Inbred C57BL; D008808:Mice, Inbred CBA; D008822:Mice, Transgenic; D011042:Poisons / Q000633:toxicity*; D011726:Pyridinium Compounds / Q000378:metabolism; D000644:Quaternary Ammonium Compounds / Q000378:metabolism; D012444:Saccule and Utricle / Q000166:cytology*; D013997:Time Factors; D050821:Transcription Factor Brn-3C / Q000235:genetics / Q000378:metabolism; D014161:Transduction, Genetic
chemical_list: D051792:Basic Helix-Loop-Helix Proteins; D001973:Bromodeoxyuridine; D004167:Diphtheria Toxin; D049452:Green Fluorescent Proteins; D066257:Heparin-binding EGF-like Growth Factor; D018398:Homeodomain Proteins; D036341:Intercellular Signaling Peptides and Proteins; D011042:Poisons; D011726:Pyridinium Compounds; D000644:Quaternary Ammonium Compounds; D050821:Transcription Factor Brn-3C; C500943:Atoh1 protein, mouse; C073804:FM1 43; C587883:HBEGF protein, human; C587884:Hbegf protein, mouse; C111223:POU4F3 protein, human