Virally Mediated Gene Therapy for Genetic Hearing Loss

描述(申请人提供)：每1000名儿童中约有1.5名在出生时耳聋，其中1/2可归因于遗传原因。对这些遗传性耳聋的治疗是相当有限的，包括对轻度到重度听力损失进行听力放大，对严重到重度听力损失进行人工耳蜗植入。基因治疗已被认为是一种潜在的遗传性听力损失治疗方法，但在这一领域的成功仍然难以捉摸。利用病毒介导的基因传递在毛细胞再生方面取得了重要进展；然而，细胞再生方面的突破可能不会使遗传性耳聋患者受益，因为潜在的遗传背景将保持不变。然而，由于耳蜗骨结构在手术通路和限制液体空间方面的进步，内耳仍然是一个有吸引力的基因治疗靶点。我们一直在研究一种转基因小鼠，它在囊泡谷氨酸转运体3(VGLUT3)基因缺失后严重耳聋，该基因与人类非综合征耳聋DFNA25基因有关。我们最近的工作通过使用腺相关病毒载体(AAV-VGLUT3)的局部单基因治疗成功地恢复了出生后小鼠的听力。这一新的初步发现为研究提供了强大的动力，如果这种治疗方法能够被优化并推广到其他形式的遗传性耳聋。这项建议的总体目标是优化病毒基因向VGLUT3基因敲除(KO)小鼠的耳蜗传递以恢复听力的方法，验证正常的突触生理学是否得到恢复，并确定该技术是否可以推广到另一种遗传性耳聋的小鼠模型，即耳铁蛋白基因敲除小鼠，一种人类遗传性耳聋的模型DFNB9。这些研究的结果可能会为未来对患有某种形式的遗传性耳聋的人类进行临床试验提供基础。

DESCRIPTION (provided by applicant): Approximately 1.5 in 1000 children are affected by deafness at birth, 1/2 of which can be attributed to a genetic cause. Treatment for these inherited forms of deafness is quite limited, and consists of hearing amplification for mild to severe hearing loss, and cochlear implantation for severe to profound hearing loss. Gene therapy has been suggested as a potential treatment for genetic hearing loss, but success in this area has remained elusive. Important advances have been made towards hair cell regeneration using virally-mediated gene delivery; however breakthroughs in cellular regeneration likely would not benefit those with genetic deafness because the underlying genetic background would be unchanged. Yet the inner ear remains an attractive target for gene therapy due to advances in surgical access and confinement of fluid space by the bony structure of the cochlea. We have been studying a transgenic mouse that is profoundly deaf after deletion of the vesicular glutamate transporter-3 (VGLUT3) gene, the same gene responsible for the human non-syndromic deafness DFNA25. Our recent work has led to successful restoration of hearing in postnatal mice by local monogenic therapy using an adeno- associated viral vector (AAV-VGLUT3). This novel initial finding provides a powerful incentive to investigation if this therapy can be optimized and generalized to other forms of genetic deafness. The overall goals of this proposal are to optimize the viral-gene delivery method to the cochlea for hearing restoration in the VGLUT3 knockout (KO) mouse, verify that normal synaptic physiology is restored, and determine whether this technique can be generalized to another mouse model of genetic deafness, the otoferlin knockout mouse, a model for the human genetic deafness DFNB9. Results from these studies may provide the foundation for future clinical trials in humans with some forms of genetic deafness.