Institute for Auditory Neuroscience and InnerEarLab, University Medical Center Göttingen, Göttingen, Germany.
Göttingen Graduate School for Neurosciences and Molecular Biosciences, University of Göttingen, Göttingen, Germany.
Life Sci Alliance. 2022 May 5;5(8). doi: 10.26508/lsa.202101338. Print 2022 Aug.
AAV-mediated optogenetic neural stimulation has become a clinical approach for restoring function in sensory disorders and feasibility for hearing restoration has been indicated in rodents. Nonetheless, long-term stability and safety of AAV-mediated channelrhodopsin (ChR) expression in spiral ganglion neurons (SGNs) remained to be addressed. Here, we used longitudinal studies on mice subjected to early postnatal administration of AAV2/6 carrying fast gating ChR f-Chrimson under the control of the human synapsin promoter unilaterally to the cochlea. f-Chrimson expression in SGNs in both ears and the brain was probed in animals aged 1 mo to 2 yr. f-Chrimson was observed in SGNs at all ages indicating longevity of ChR-expression. SGN numbers in the AAV-injected cochleae declined with age faster than in controls. Investigations were extended to the brain in which viral transduction was observed across the organ at varying degrees irrespective of age without observing viral spread-related pathologies. No viral DNA or virus-related histopathological findings in visceral organs were encountered. In summary, our study demonstrates life-long (24 mo in mice) expression of f-Chrimson in SGNs upon single AAV-dosing of the cochlea.
AAV 介导的光遗传学神经刺激已成为恢复感觉障碍功能的一种临床方法，并且已经在啮齿动物中表明了听觉恢复的可行性。尽管如此，AAV 介导的通道型视蛋白（ChR）在螺旋神经节神经元（SGN）中的长期稳定性和安全性仍有待解决。在这里，我们使用纵向研究在早期产后单侧给予携带快速门控 ChR f-Chrimson 的 AAV2/6 的小鼠中进行，该 ChR 受人类突触蛋白启动子的控制。在 1 个月至 2 岁的动物中探测了双耳和大脑中的 SGN 中 f-Chrimson 的表达。在所有年龄的 SGN 中均观察到 f-Chrimson，表明 ChR 表达的长寿性。与对照组相比，AAV 注射耳蜗中的 SGN 数量随年龄增长的速度更快。研究扩展到大脑，无论年龄大小，在不同程度上观察到病毒转导，而没有观察到与病毒传播相关的病理学。在内脏器官中未遇到病毒 DNA 或与病毒相关的组织病理学发现。总之，我们的研究表明，单次 AAV 耳蜗给药后，f-Chrimson 在 SGN 中可长期（在小鼠中为 24 个月）表达。
