Hair cell uptake of gentamicin in the developing mouse utricle
Hair cell uptake of gentamicin in the developing mouse utricle
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发育中的小鼠椭圆囊中的毛细胞摄取庆大霉素。
DOI：
10.1002/jcp.30228
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发表时间：
2020-12-23
影响因子：
5.6
通讯作者：
Ren，Dongdong
中科院分区：
文献类型：
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作者：
Qian，Xiaoqing;He，Ziyu;Ren，Dongdong
鼓室内注射庆大霉素已被证明是治疗顽固性前庭功能障碍的有效方法。然而，到目前为止，大多数研究都集中在耳蜗部，因此对庆大霉素在听觉系统的对应物，特别是前庭毛细胞(Hcs)的分布和吸收知之甚少。在此，我们采用体内和体外相结合的方法，用庆大霉素-德克萨斯红(GTTR)结合物研究了庆大霉素对发育中的哺乳动物椭圆型HCS的前庭毒性作用机制。定量分析表明，纹状体Hcs对GTTR的摄取显著高于纹外Hcs。此外，纹状体GTTR的荧光强度在出生后1~8天逐渐增强，在出生后8~9天达到高峰。在体外，卵胞外植体与GTTR一起孵育，候选吸收管道，包括机械转导(MET)通道和HC的内吞作用，分别被抑制。在正常和应激条件下，MET通道阻断剂奎宁均可抑制HCS摄取GTTR。同时，在CoCl2缺氧模型中，内吞抑制只减少GTTR的摄取。综上所述，MET通道的成熟介导了GTTR被前庭Hcs摄取。在应激条件下，MET通道发挥着明显的作用，表现为通道依赖的应激增强GTTR通透性，而内吞作用以更具选择性的方式参与GTTR的进入。
Intratympanic injection of gentamicin has proven to be an effective therapy for intractable vestibular dysfunction. However, most studies to date have focused on the cochlea, so little is known about the distribution and uptake of gentamicin by the counterpart of the auditory system, specifically vestibular hair cells (HCs). Here, with a combination of in vivo and in vitro approaches, we used a gentamicin‐Texas Red (GTTR) conjugate to investigate the mechanisms of gentamicin vestibulotoxicity in the developing mammalian utricular HCs. In vivo, GTTR fluorescence was concentrated in the apical cytoplasm and the cellular membrane of neonatal utricular HCs, but scarce in the nucleus of HCs and supporting cells. Quantitative analysis showed the GTTR uptake by striolar HCs was significantly higher than that in the extrastriola. In addition, the GTTR fluorescence intensity in the striola was increased gradually from 1 to 8 days, peaking at 8–9 days postnatally. In vitro, utricle explants were incubated with GTTR and candidate uptake conduits, including mechanotransduction (MET) channels and endocytosis in the HC, were inhibited separately. GTTR uptake by HCs could be inhibited by quinine, a blocker of MET channels, under both normal and stressed conditions. Meanwhile, endocytic inhibition only reduced GTTR uptake in the CoCl2hypoxia model. In sum, the maturation of MET channels mediated uptake of GTTR into vestibular HCs. Under stressed conditions, MET channels play a pronounced role, manifested by channel‐dependent stress enhanced GTTR permeation, while endocytosis participates in GTTR entry in a more selective manner.