Novel mutations in GJB1 trigger intracellular aggregation and stress granule formation in X-linked Charcot-Marie-Tooth Disease.
Novel mutations in GJB1 trigger intracellular aggregation and stress granule formation in X-linked Charcot-Marie-Tooth Disease.
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GJB1 的新突变触发 X 连锁腓骨肌病的细胞内聚集和应激颗粒形成
DOI：
10.3389/fnins.2022.972288
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发表时间：
2022
影响因子：
4.3
通讯作者：
Li, Chuanzhou
中科院分区：
文献类型：
--
作者：
Chu, Fan;Xu, Jiaming;Wang, Yong;Li, Yingjie;Wang, Yaling;Liu, Zhijun;Li, Chuanzhou
1型（CMT1X）是第二种最常见的遗传性周围神经病变，由间隙连接β -1 （GJB1）基因突变引起。利用靶向外显子组测序，研究了来自中国中南部的4个CMT家族，发现了GJB1的两个新的错义变体（p.F31S和p.W44G）和两个先前报道的变体（p.R220Pfs*23和p.Y157H）。4个先证者均表现为典型的早发性周围神经病变，其中R220Pfs*23携带者在中枢神经系统也有神经系统表现。构建GJB1表达载体，进行体外细胞生物学分析。在转染后的不同时间点，flag标记的GJB1的表达显示出明显的蛋白质聚集，包括野生型和突变型，免疫染色和免疫印迹显示。基于洗涤剂的序列分离证实，所有突变体都比野生型表达更高，更容易聚集，而R220Pfs*23突变体在组中显示出最多的sds可溶性多聚物和单体。此外，细胞内聚集可能发生在内质网室而不是高尔基体。间隙连接斑块存在于所有组中，仅在移码突变体中受损。进一步的证据表明，突变的GJB1诱导显著的细胞内应激颗粒形成和细胞活力受损，表明自聚集体的细胞毒性。总之，我们的研究结果证明了新的GJB1变异诱导的细胞应激和功能障碍，并为理解GJB1- cmtx1和其他相关疾病的病理机制提供了见解。
X-linked Charcot-Marie-Tooth Disease type 1(CMT1X) is the second most common form of inherited peripheral neuropathy that is caused by mutations in the gap junction beta-1 (GJB1) gene. Using targeted exome-sequencing, we investigated four CMT families from central-southern China and identified two novel missense variants (p.F31S and p.W44G) and two previously reported variants (p.R220Pfs*23 and p.Y157H) of GJB1. All four probands presented typical early-onset peripheral neuropathy, of which the R220Pfs*23 carrier also had neurologic manifestations in the central nervous system. We then constructed GJB1 expression vectors and performed cell biological analysis in vitro. Expression of FLAG-tagged GJB1 at various time points after transfection revealed evident protein aggregation with both wild-type and mutant forms, indicated with immunostaining and immunoblotting. Detergent-based sequential fractionation confirmed that all mutants were higher expressed and more prone to aggregate than the wild-type, whereas the R220Pfs*23 mutant showed the greatest amount of SDS-soluble multimers and monomers among groups. Moreover, intracellular aggregation probably occurs in the endoplasmic reticulum compartment rather than the Golgi apparatus. Gap junction plaques were present in all groups and were only compromised in frameshift mutant. Further evidence reveals significant intracellular stress granule formation induced by mutated GJB1 and impaired cell viability indicative of cytotoxicity of self-aggregates. Together, our findings demonstrate novel GJB1 variants-induced cell stress and dysfunction and provide insights into understanding the pathomechanisms of GJB1-CMTX1 and other related disorders.
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影响因子：
2.9
作者：
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通讯作者：
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影响因子：
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作者：
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通讯作者：
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