Mutations of MAP1B encoding a microtubule-associated phosphoprotein cause sensorineural hearing loss
Mutations of MAP1B encoding a microtubule-associated phosphoprotein cause sensorineural hearing loss
复制标题
编码微管相关磷蛋白的 MAP1B 突变导致感音神经性听力损失
DOI：
10.1172/jci.insight.136046
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发表时间：
2020-12-03
期刊：
影响因子：
8
通讯作者：
Guan, Min-Xin
中科院分区：
文献类型：
--
作者：
Cui, Limei;Zheng, Jing;Guan, Min-Xin
螺旋神经节细胞缺陷引起的耳聋的病理生理机制仍然是难以捉摸的。使用全外显子组测序方法，结合功能测定和小鼠疾病模型，我们确定了编码高度保守的微管相关蛋白的潜在的新的致病MAP 1B基因。在3个无血缘关系的中国家系中发现3个新的杂合子MAP 1B突变（c.4198A>G，p.1400S>G; c.2768T>C，p.923I>T; c.5512T>C，p.1838F>L）与非综合征型感音神经性耳聋的常染色体显性遗传共分离。在这里，我们表明，MAP 1B是高度表达的螺旋神经节神经元在小鼠耳蜗。使用由携带MAP 1B突变的患者和对照受试者的多能干细胞产生的耳感觉神经元样细胞，我们证明了p.1400S>G突变导致MAP 1B水平降低和磷酸化不足，这与微管稳定性和动力学有关。引人注目的是，耳感觉神经元样细胞表现出微管，轴突伸长，和缺陷的电生理特性的干扰动力学。这些衍生的耳感觉神经元样细胞的功能障碍通过使用CRISPR/Cas9技术遗传校正MAP 1B突变来挽救。通过Map 1b杂合子KO小鼠的听力评估证实了MAP 1B参与听力。这些突变小鼠表现出迟发性进行性感音神经性听力损失，在高频中更为明显。从Map 1b突变小鼠分离的螺旋神经节神经元表现出磷酸化不足和微管动力学紊乱。Map 1b缺陷导致螺旋神经节神经元的形态和电生理缺陷，但它不影响小鼠耳蜗的形态。因此，我们的数据表明，MAP 1B缺陷引起的螺旋神经节神经元功能障碍导致听力损失。
The pathophysiology underlying spiral ganglion cell defect-induced deafness remains elusive. Using the whole exome sequencing approach, in combination with functional assays and a mouse disease model, we identified the potentially novel deafness-causative MAP1B gene encoding a highly conserved microtubule-associated protein. Three novel heterozygous MAP1B mutations (c.4198A>G, p.1400S>G; c.2768T>C, p.923I>T; c.5512T>C, p.1838F>L) were cosegregated with autosomal dominant inheritance of nonsyndromic sensorineural hearing loss in 3 unrelated Chinese families. Here, we show that MAP1B is highly expressed in the spiral ganglion neurons in the mouse cochlea. Using otic sensory neuron-like cells, generated by pluripotent stem cells from patients carrying the MAP1B mutation and control subject, we demonstrated that the p.1400S>G mutation caused the reduced levels and deficient phosphorylation of MAP1B, which are involved in the microtubule stability and dynamics. Strikingly, otic sensory neuron-like cells exhibited disturbed dynamics of microtubules, axonal elongation, and defects in electrophysiological properties. Dysfunctions of these derived otic sensory neuron-like cells were rescued by genetically correcting MAP1B mutation using CRISPR/Cas9 technology. Involvement of MAP1B in hearing was confirmed by audiometric evaluation of Map1b heterozygous KO mice. These mutant mice displayed late-onset progressive sensorineural hearing loss that was more pronounced in the high frequencies. The spiral ganglion neurons isolated from Map1b mutant mice exhibited the deficient phosphorylation and disturbed dynamics of microtubules. Map1b deficiency yielded defects in the morphology and electrophysiology of spiral ganglion neurons, but it did not affect the morphologies of cochlea in mice. Therefore, our data demonstrate that dysfunctions of spiral ganglion neurons induced by MAP1B deficiency caused hearing loss.