Liu Yuhe, Okada Takashi, Shimazaki Kuniko, Sheykholeslami Kianoush, Nomoto Tatsuya, Muramatsu Shin-Ichi, Mizukami Hiroaki, Kume Akihiro, Xiao Shuifang, Ichimura Keiichi, Ozawa Keiya
Division of Genetic Therapeutics, Jichi Medical University, Tochigi, Japan.
Mol Ther. 2008 Mar;16(3):474-80. doi: 10.1038/sj.mt.6300379. Epub 2008 Jan 8.
Since standard aminoglycoside treatment progressively causes hearing disturbance with hair cell degeneration, systemic use of the drugs is limited. Adeno-associated virus (AAV)-based vectors have been of great interest because they mediate stable transgene expression in a variety of postmitotic cells with minimal toxicity. In this study, we investigated the effects of regulated AAV1-mediated glial cell line-derived neurotrophic factor (GDNF) expression in the cochlea on aminoglycoside-induced damage. AAV1-based vectors encoding GDNF or vectors encoding GDNF with an rtTA2s-S2 Tet-on regulation system were directly microinjected into the rat cochleae through the round window at 5 x 10(10) genome copies/body. Seven days after the virus injection, a dose of 333 mg/kg of kanamycin was subcutaneously given twice daily for 12 consecutive days. GDNF expression in the cochlea was confirmed and successfully modulated by the Tet-on system. Monitoring of the auditory brain stem response revealed an improvement of cochlear function after GDNF transduction over the frequencies tested. Damaged spiral ganglion cells and hair cells were significantly reduced by GDNF expression. Our results suggest that AAV1-mediated expression of GDNF using a regulated expression system in the cochlea is a promising strategy to protect the cochlea from aminoglycoside-induced damage.
由于标准的氨基糖苷类药物治疗会随着毛细胞变性逐渐导致听力障碍，因此该药物的全身应用受到限制。基于腺相关病毒（AAV）的载体备受关注，因为它们能在多种有丝分裂后细胞中介导稳定的转基因表达，且毒性极小。在本研究中，我们调查了耳蜗中受调控的AAV1介导的胶质细胞源性神经营养因子（GDNF）表达对氨基糖苷类药物诱导损伤的影响。将编码GDNF的基于AAV1的载体或编码带有rtTA2s - S2 Tet - on调控系统的GDNF的载体以5×10（10）基因组拷贝/体的剂量通过圆窗直接显微注射到大鼠耳蜗中。病毒注射7天后，每天皮下注射两次333 mg/kg的卡那霉素，连续注射12天。通过Tet - on系统证实并成功调节了耳蜗中的GDNF表达。对听觉脑干反应的监测显示，在测试频率范围内，GDNF转导后耳蜗功能得到改善。GDNF表达显著减少了受损的螺旋神经节细胞和毛细胞。我们的结果表明，在耳蜗中使用受调控表达系统由AAV1介导GDNF表达是一种保护耳蜗免受氨基糖苷类药物诱导损伤的有前景的策略。
