A Recurrent Gain-of-Function Mutation in CLCN6, Encoding the ClC-6 Cl-/H+-Exchanger, Causes Early-Onset Neurodegeneration.
A Recurrent Gain-of-Function Mutation in CLCN6, Encoding the ClC-6 Cl-/H+-Exchanger, Causes Early-Onset Neurodegeneration.
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DOI：
10.1016/j.ajhg.2020.11.004
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发表时间：
2020-11
影响因子：
9.8
通讯作者：
Maya M. Polovitskaya;Carlo Barbini;D. Martinelli;Frederike L Harms;F. Sessions;Cole;Paolo Calligari;G. Bocchinfuso;L. Stella;Marcello;Niceta;T. Rizza;M. Shinawi;Kathleen Sisco;J. Johannsen;Jonas;Denecke;R. Carrozzo;D. Wegner;K. Kutsche;Marco;Tartaglia;T. Jentsch
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文献类型：
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作者：
Maya M. Polovitskaya;Carlo Barbini;D. Martinelli;Frederike L Harms;F. Sessions;Cole;Paolo Calligari;G. Bocchinfuso;L. Stella;Marcello;Niceta;T. Rizza;M. Shinawi;Kathleen Sisco;J. Johannsen;Jonas;Denecke;R. Carrozzo;D. Wegner;K. Kutsche;Marco;Tartaglia;T. Jentsch
由于有丝分裂后神经元特别依赖于细胞内聚集体的清除，因此内溶酶体系统的功能障碍通常与神经退行性疾病有关。内小体和溶酶体的充分功能需要微调的管腔离子稳态和跨膜离子通量。内质粒ClC-−/H+交换器是质子泵和腔内Cl-−积累的电子分流管。我们现在报告三名患有严重神经退行性疾病的无血缘关系的儿童，他们携带CLCN6中的SAMIED novoc.1658A&Gt；G(p.Tyr553Cys)突变，编码晚期内体CL−/H+-交换器ClC-6。当Clcn6−/−小鼠仅有轻微的神经元溶酶体存储异常时，受影响的个体表现出严重的发育延迟，表现为明显的全身性低眼压、呼吸功能不全，以及在磁共振扫描中大脑脚、中脑和/或脑干的不同神经变性和扩散限制。P.Tyr553Cys的氨基酸取代强烈地减缓了ClC-6的门控和电流幅度的增加，特别是在晚期内体的酸性pH下。CLC-6Tyr553Cys，而不是CLC-6WT，可产生酸化程度较差的LAMP1阳性空泡。它们的产生严格需要ClC-6离子的运输，如缺乏运输的双突变体所表明的那样，并依赖于Cl−/H+交换，如结合解偶联的p.Glu200Ala替换所揭示的那样。无论是CLC-6Tyr553Cys/Glu200Ala还是CLC-6Glu200Ala，都会产生轻微增大的囊泡，这表明之前与婴儿痉挛和小头畸形有关的P.Glu200Ala也是致病的。巴菲罗星处理抑制了液泡的产生，表明H+驱动的Cl-−的积累在渗透压作用下驱动了囊泡的扩大。我们的工作建立了与神经疾病相关的CLCN6突变，其临床特征的谱取决于等位基因对ClC-6功能的不同影响。
Dysfunction of the endolysosomal system is often associated with neurodegenerative disease because postmitotic neurons are particularly reliant on the elimination of intracellular aggregates. Adequate function of endosomes and lysosomes requires finely tuned luminal ion homeostasis and transmembrane ion fluxes. Endolysosomal CLC Cl−/H+exchangers function as electric shunts for proton pumping and in luminal Cl−accumulation. We now report three unrelated children with severe neurodegenerative disease, who carry the samede novoc.1658A>G (p.Tyr553Cys) mutation inCLCN6, encoding the late endosomal Cl−/H+-exchanger ClC-6. WhereasClcn6−/−mice have only mild neuronal lysosomal storage abnormalities, the affected individuals displayed severe developmental delay with pronounced generalized hypotonia, respiratory insufficiency, and variable neurodegeneration and diffusion restriction in cerebral peduncles, midbrain, and/or brainstem in MRI scans. The p.Tyr553Cys amino acid substitution strongly slowed ClC-6 gating and increased current amplitudes, particularly at the acidic pH of late endosomes. Transfection of ClC-6Tyr553Cys, but not ClC-6WT, generated giant LAMP1-positive vacuoles that were poorly acidified. Their generation strictly required ClC-6 ion transport, as shown by transport-deficient double mutants, and depended on Cl−/H+exchange, as revealed by combination with the uncoupling p.Glu200Ala substitution. Transfection of either ClC-6Tyr553Cys/Glu200Alaor ClC-6Glu200Alagenerated slightly enlarged vesicles, suggesting that p.Glu200Ala, previously associated with infantile spasms and microcephaly, is also pathogenic. Bafilomycin treatment abrogated vacuole generation, indicating that H+-driven Cl−accumulation osmotically drives vesicle enlargement. Our work establishes mutations inCLCN6associated with neurological diseases, whose spectrum of clinical features depends on the differential impact of the allele on ClC-6 function.