miR-431 is involved in regulating cochlear function by targeting Eya4
miR-431 is involved in regulating cochlear function by targeting Eya4
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miR-431通过靶向Eya4参与调节耳蜗功能
DOI：
10.1016/j.bbadis.2016.08.015
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发表时间：
2016-11-01
影响因子：
6.2
通讯作者：
Zhu, Dahai
中科院分区：
文献类型：
--
作者：
Fan, Yue;Zhang, Ying;Zhu, Dahai
为了了解microRNA与听力损失的关系，并帮助阐明遗传性耳聋的原因，我们研究了耳蜗中miR-431的功能。我们首先采用实时荧光定量PCR和miRNA原位杂交技术研究了耳蜗螺旋神经节神经元（SGNs）中miR-431的时空表达谱。这些研究表明，miR-431在新生小鼠耳蜗中的SGN中表达较高，并随着发育的进展而降低。为了测试miR-431的功能作用，我们建立了miR-431过表达转基因（Tg）小鼠。耳蜗基底膜和耳蜗切片的表面制备显示Tg和野生型（Wt）小鼠之间没有重大的结构差异。然而，在Tg和Wt小鼠的听觉脑干反应（ABR）的比较表明，在Tg小鼠的ABR阈值显着高于在Wt小鼠。值得注意的是，Tg小鼠中SGN的密度显著低于Wt小鼠。我们还发现，在培养的初级SGN从Tg耳蜗SGN的成熟SGN的比例较低，其轴突较短。生物信息学分析预测，miR-431的mRNA靶点是Eya 4，这一发现得到了荧光素酶报告基因测定和蛋白质印迹法的证实。重要的是，在Tg小鼠耳蜗中过表达miR-431抑制Eya 4 mRNA的翻译，导致EYA 4缺陷。因此，Tg小鼠耳蜗中过量的miR-431可能是SGN稀疏的原因，而SGN稀疏又可能导致听力损失。(C)2016由Elsevier B. V.出版
To understand the relationship between microRNAs and hearing loss and help clarify the causes of hereditary deafness, we studied the functions of miR-431 in cochleae. We first investigated the spatial-temporal expression profiles of miR-431 in spiral ganglion neurons (SGNs) in cochleae using real-time PCR and miRNA in situ hybridization. These studies showed that expression of miR-431 was high in SGNs in the cochleae of newborn mice, and decreased as development progressed. To test the functional effects of miR-431, we established miR-431 overexpressing transgenic (Tg) mice. Surface preparations of the cochlear basilar membrane and cochlear sections revealed no major structural differences between Tg and wild-type (Wt) mice. However, a comparison of auditory brain stem responses (ABRs) in Tg and Wt mice showed that ABR thresholds were significantly higher in Tg mice than in Wt mice. Notably, the density of SGNs was significantly lower in Tg mice than in Wt mice. We also found that the proportion of mature SGNs in cultures of primary SGNs from Tg cochleae was lower and their axons were shorter. A bioinformatics analysis predicted that the mRNA target of miR-431 was Eya4, a finding confirmed by luciferase reporter assays and western blotting. Importantly, overexpression of miR-431 in cochleae of Tg mice inhibited the translation of Eya4 mRNA, leading to a deficiency of EYA4. Thus, excessive amounts of miR-431 in cochleae of Tg mice may be the cause of sparse SGNs, which in turn could be responsible for hearing loss. (C) 2016 Published by Elsevier B.V.