PDF(Pubmed)
Abstract：
Sensorineural hearing loss is prevalent within society affecting the quality of life of 460 million worldwide. In the majority of cases, this is due to insult or degeneration of mechanosensory hair cells in the cochlea. In adult mammals, hair cell loss is irreversible as sensory cells are not replaced spontaneously. Genetic inhibition of Notch signaling had been shown to induce hair cell formation by transdifferentiation of supporting cells in young postnatal rodents and provided an impetus for targeting Notch pathway with small molecule inhibitors for hearing restoration. Here, the oto-regenerative potential of different γ-secretase inhibitors (GSIs) was evaluated in complementary assay models, including cell lines, organotypic cultures of the organ of Corti and cochlear organoids to characterize two novel GSIs (CPD3 and CPD8). GSI-treatment induced hair cell gene expression in all these models and was effective in increasing hair cell numbers, in particular outer hair cells, both in baseline conditions and in response to ototoxic damage. Hair cells were generated from transdifferentiation of supporting cells. Similar findings were obtained in cochlear organoid cultures, used for the first time to probe regeneration following sisomicin-induced damage. Finally, effective absorption of a novel GSI through the round window membrane and hair cell induction was attained in a whole cochlea culture model and in vivo pharmacokinetic comparisons of transtympanic delivery of GSIs and different vehicle formulations were successfully conducted in guinea pigs. This preclinical evaluation of targeting Notch signaling with novel GSIs illustrates methods of characterization for hearing restoration molecules, enabling translation to more complex animal studies and clinical research.
摘要：
感音神经性听力损失在社会中普遍存在，影响着全世界4.6亿人的生活质量。在大多数情况下,这是由于耳蜗机械感觉毛细胞的损伤或退化。在成年哺乳动物中，毛细胞损失是不可逆的，因为感觉细胞不能自发地替换。已显示Notch信号的遗传抑制通过年轻出生后啮齿动物的支持细胞的转分化来诱导毛细胞形成，并为用小分子抑制剂靶向Notch途径以恢复听力提供了动力。这里,不同γ-分泌酶抑制剂（GSI）的卵细胞再生潜力在互补试验模型中进行了评估，包括细胞系,Corti和耳蜗类器官的器官型培养，以表征两个新的GSI（CPD3和CPD8）。GSI处理在所有这些模型中诱导毛细胞基因表达，并有效增加毛细胞数量，特别是外毛细胞，在基线条件下和对耳毒性损伤的反应中。毛细胞由支持细胞的转分化产生。在耳蜗类器官培养中获得了类似的发现，首次用于探测sisomicin引起的损伤后的再生。最后,在整个耳蜗培养模型中实现了通过圆窗膜和毛细胞诱导的新型GSI的有效吸收，并且在豚鼠中成功地进行了GSI和不同载体制剂的经苯乙烯递送的体内药代动力学比较。这种用新型GSI靶向Notch信号的临床前评估说明了听力恢复分子的表征方法。使翻译更复杂的动物研究和临床研究。
