title: HSV amplicon-mediated neurotrophin-3 expression protects murine spiral ganglion neurons from cisplatin-induced damage.
abstract: Ototoxicity is a major dose-limiting side effect of cisplatin (DDP) administration due to its propensity to induce destruction of hair cells and neurons in the auditory system. Previous studies demonstrated that TrkC-expressing spiral ganglion neurons (SGN) are protected from the cytotoxic effects of DDP by localized delivery of the trophic factor neurotrophin-3 (NT-3). Successful in vivo implementation of such a therapy requires the development of an efficient gene delivery vehicle for expression of NT-3 within the cochlea. To this end, we constructed a herpes simplex virus (HSV) amplicon vector that expressed a c-Myc-tagged NT-3 chimera (HSVnt-3myc). Helper virus-free vector stocks were initially evaluated in vitro for their capacity to direct expression of NT-3 mRNA and protein. Transduction of cultured murine cochlear explants with HSVnt-3myc resulted in production of NT-3 mRNA and protein up to 3 ng/ml as measured over a 48-h period in culture supernatants. To determine whether NT-3 overexpression could abrogate DDP toxicity, cochlear explants were transduced with HSVnt-3myc or a murine intestinal alkaline phosphatase-expressing control vector, HSVmiap, and then exposed to cisplatin. HSVnt-3myc-transduced cochlear explants harbored significantly greater numbers of surviving SGNs than those infected with control virus. These data demonstrate that amplicon-mediated NT-3 transduction can attenuate the ototoxic action of DDP on organotypic culture. The potency of NT-3 in protecting spiral ganglion neurons from degeneration suggests that in vivo neurotrophin-based gene therapy may be useful for the prevention and/or treatment of hearing disorders.
authors.affiliation: Division of Otolaryngology, University of Rochester School of Medicine and Dentistry, Rochester, New York 14642, USA.
authors.forename: X
authors.initials: X
authors.lastname: Chen
authors.forename: R D
authors.initials: RD
authors.lastname: Frisina
authors.forename: W J
authors.initials: WJ
authors.lastname: Bowers
authors.forename: D R
authors.initials: DR
authors.lastname: Frisina
authors.forename: H J
authors.initials: HJ
authors.lastname: Federoff
mesh_terms: D000818:Animals; D015153:Blotting, Western; D016923:Cell Death / Q000187:drug effects; D002945:Cisplatin / Q000633:toxicity*; D003051:Cochlea / Q000378:metabolism; D003587:Cytomegalovirus / Q000235:genetics; D017931:DNA Primers / Q000737:chemistry; D004797:Enzyme-Linked Immunosorbent Assay; D016259:Genes, myc / Q000235:genetics / Q000502:physiology; D006311:Hearing Disorders / Q000139:chemically induced / Q000517:prevention & control; D007124:Immunoenzyme Techniques; D016501:Neurites / Q000737:chemistry; D009474:Neurons / Q000187:drug effects / Q000473:pathology; D020933:Neurotrophin 3 / Q000235:genetics / Q000378:metabolism*; D011993:Recombinant Fusion Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D020133:Reverse Transcriptase Polymerase Chain Reaction; D018139:Simplexvirus / Q000235:genetics*; D013136:Spiral Ganglion / Q000187:drug effects* / Q000473:pathology
chemical_list: D017931:DNA Primers; D020933:Neurotrophin 3; D011993:Recombinant Fusion Proteins; D002945:Cisplatin