PDF(Pubmed)
Abstract：
Adeno-associated virus (AAV)-mediated gene transfer has shown promise in rescuing mouse models of genetic hearing loss, but how viral capsid and promoter selection affects efficacy is poorly characterized. Here, we tested combinations of AAVs and promoters to deliver Tmprss3, mutations in which are associated with hearing loss in humans. Tmprss3tm1/tm1 mice display severe cochlear hair cell degeneration, loss of auditory brainstem responses, and delayed loss of spiral ganglion neurons. Under the ubiquitous CAG promoter and AAV-KP1 capsid, Tmprss3 overexpression caused striking cytotoxicity in vitro and in vivo and failed to rescue degeneration or dysfunction of the Tmprss3tm1/tm1 cochlea. Reducing the dosage or using AAV-DJ-CAG-Tmprss3 diminished cytotoxicity without rescue of the Tmprss3tm1/tm1 cochlea. Finally, the combination of AAV-KP1 capsid and the EF1α promoter prevented cytotoxicity and reduced hair cell degeneration, loss of spiral ganglion neurons, and improved hearing thresholds in Tmprss3tm1/tm1 mice. Together, our study illustrates toxicity of exogenous genes and factors governing rescue efficiency, and suggests that cochlear gene therapy likely requires precisely targeted transgene expression.
摘要：
腺相关病毒（AAV）介导的基因转移在挽救遗传性听力损失的小鼠模型中显示出希望，但是病毒衣壳和启动子选择如何影响功效的特征很少。这里,我们测试了AAV和启动子的组合以递送Tmprss3,突变与人类听力损失相关.Tmprss3tm1/tm1小鼠表现出严重的耳蜗毛细胞变性，听觉脑干反应丧失,和螺旋神经节神经元的延迟丢失。在普遍存在的CAG启动子和AAV-KP1衣壳下，Tmprss3过表达在体外和体内引起强烈的细胞毒性，并且未能挽救Tmprss3tm1/tm1耳蜗的变性或功能障碍。减少剂量或使用AAV-DJ-CAG-Tmprss3减少了细胞毒性而没有拯救Tmprss3tm1/tm1耳蜗。最后,AAV-KP1衣壳和EF1α启动子的组合防止细胞毒性和减少毛细胞变性，螺旋神经节神经元丢失，改善了Tmprss3tm1/tm1小鼠的听力阈值。一起,我们的研究说明了外源基因的毒性和控制救援效率的因素，并提示耳蜗基因治疗可能需要精确靶向的转基因表达。
