使用AAV8BP2和后半规管注射实现高效的内淋巴囊靶向基因递送

文献信息

中文摘要

SLC26A4基因编码阴离子转运蛋白pendrin，其突变是遗传性听力损失最常见的遗传原因之一，包括Pendred综合征和DFNB4。Pendrin在维持内耳离子稳态中起关键作用，尤其是在内淋巴囊（ES）中，使其成为基因替代策略的重要治疗靶点。然而，将治疗基因高效递送至相关内耳结构仍是临床转化的主要挑战。在本研究中，我们在小鼠中评估了AAV8BP2（一种工程化AAV8衍生衣壳）的内耳转导谱，并与AAV2.7m8和AAV8进行比较。新生小鼠在出生后第0天（P0）接受后后半规管（PSCC）注射，并在P7评估耳蜗和ES中的病毒转导。为了检查病毒转导的年龄依赖性差异，我们在P21注射的成年小鼠中进行了额外实验，并在P28进行分析。我们还比较了三种内耳基因转移的手术递送途径：PSCC注射、圆窗膜（RWM）注射以及RWM注射联合PSCC开窗术。AAV8BP2在新生和成年小鼠中均有效转导ES，并且在新生给药后显示比AAV8更高的螺旋隆起GFP表达。在成年小鼠中评估的三种递送途径中，PSCC注射实现了最高的ES转导，同时保持与基于RWM的方法相当的耳蜗毛细胞转导。总之，这些发现定义了所测试AAV衣壳和递送途径的相对转导谱，并为选择SLC26A4靶向内耳基因治疗的载体-递送途径组合提供了基础。

英文摘要

Mutations in SLC26A4, which encodes the anion transporter pendrin, represent one of the most common genetic causes of hereditary hearing loss, including Pendred syndrome and DFNB4. Pendrin plays a critical role in maintaining ion homeostasis within the inner ear, particularly in the endolymphatic sac (ES), making it an important therapeutic target for gene replacement strategies. However, efficient delivery of therapeutic genes to relevant inner ear structures remains a major challenge for clinical translation. In this study, we evaluated the inner ear transduction profile of AAV8BP2, an engineered AAV8-derived capsid, in comparison with AAV2.7m8 and AAV8 in mice. Neonatal mice received posterior semicircular canal (PSCC) injections at postnatal day 0 (P0), and viral transduction in the cochlea and ES was assessed at P7. To examine age-dependent differences in viral transduction, additional experiments were performed in adult mice injected at P21 and analyzed at P28. We also compared three surgical delivery routes for inner ear gene transfer: PSCC injection, round window membrane (RWM) injection, and RWM injection combined with PSCC fenestration. AAV8BP2 effectively transduced the ES in both neonatal and adult mice and showed greater GFP expression in the spiral prominence than AAV8 following neonatal administration. Among the three delivery routes evaluated in adult mice, PSCC injection achieved the highest ES transduction while maintaining cochlear hair cell transduction comparable to that achieved with RWM-based approaches. Together, these findings define the relative transduction profiles of the tested AAV capsids and delivery routes and provide a basis for selecting vector-delivery route combinations for SLC26A4-targeted inner ear gene therapy.