A novel cysteine-sparing G73A mutation of NOTCH3 in a Chinese CADASIL family
A novel cysteine-sparing G73A mutation of NOTCH3 in a Chinese CADASIL family
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中国 CADASIL 家族中 NOTCH3 的新型半胱氨酸保留 G73A 突变
DOI：
10.1007/s10048-019-00592-3
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发表时间：
2019-11-13
期刊：
影响因子：
2.2
通讯作者：
Sun, Xiulian
中科院分区：
文献类型：
--
作者：
Huang, Liyan;Li, Wei;Sun, Xiulian
常染色体显性遗传性脑动脉病合并皮质下梗塞和白质脑病(CADASIL)是导致中风和血管性痴呆的最常见的单基因疾病。CADASIL是一种遗传性小血管疾病，由神经源性Notch同源蛋白3(NOTCH3)基因突变引起。NOTCH3是一种大的I型膜受体，主要表达于血管平滑肌细胞和周细胞。大多数已识别的突变导致在EGF样重复序列中插入或缺失半胱氨酸残基。到目前为止，已经描述了一些半胱氨酸节约型突变的病例。遗传分析发现了CADASIL家族中NOTCH3的一个新突变。分子分析揭示了其可能的致病机制。在本文中，我们提出了一个新的NOTCH3基因外显子3(c.218G>；C，p.G73A)半胱氨酸省略突变。相同突变的家族携带者表现出CADASIL特有的症状和影像异常。甘氨酸73位于EGF样结构域1的C5-C6二硫键之间，显示出从人类到斑马鱼的高度保守性。此前已有研究表明，突变体NOTCH3易于聚集的特性在CADASIL的致病机制中起到了细胞毒作用。在这里，我们用野生型(WT)和C.218G>；C(p.G73A)NOTCH3ECD质粒转染的HEK293细胞在体外研究了新突变的致病机制，我们发现P.G73A NOTCH3ECD更容易形成聚集和抗降解。此外，P.G73A NOTCH3ECD通过促进细胞凋亡而降低了细胞的活力。两个已知的CADASIL突变体R133C和R75P与G73A突变体的结果相似。我们的研究发现G73A是导致CADASIL的NOTCH3的一个新的突变，并发现G73A突变和两个已知的突变体R75P和R133C降低了NOTCH3的蛋白质周转并诱导了细胞死亡。
Cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy (CADASIL) is the most common monogenic disease leading to stroke and vascular dementia. CADASIL is an inherited small blood vessel disease caused by mutations in the gene encoding the neurogenic locus notch homolog protein 3 (NOTCH3). NOTCH3 is large type I membrane receptor mainly expressed in vascular smooth muscle cells and pericytes. Most identified mutations result in insert or deletion of a cysteine residue within the EGF-like repeats. To date, some cases with a cysteine-sparing mutant have been described. Genetic analysis revealed a novel mutation in NOTCH3 in a CADASIL family. Molecular analysis revealed its potential pathogenic mechanism in causing CADASIL. In this paper, we present a Chinese family with a novel cysteine-sparing mutation in exon 3 (c.218G>C, p.G73A) of the NOTCH3 gene. Family carriers of the same mutation presented with symptoms and imaging abnormalities characteristic of CADASIL. The location of glycine 73 in between C5-C6 disulfide bond of EGF-like domain 1 shows high conservation from humans to zebra fish. It has previously been suggested that the aggregate-prone property of mutant NOTCH3 contributes to a cytotoxic effect in the pathogenic mechanism underlying CADASIL. Here, we investigated the pathogenic mechanism of the new mutation in vitro using HEK293 cells transfected with either a wild-type (WT) or c.218G>C (p.G73A) NOTCH3ECDplasmids, and we found p.G73A NOTCH3ECDwas more prone to form aggregation and resistant to degradation. Moreover, the p.G73A NOTCH3ECDcompromised cell viability by promoting apoptosis. Two known CADASIL mutants R133C and R75P showed similar results with G73A mutants. Our study here identified G73A as a new mutation in NOTCH3 to cause CADASIL and revealed that the G73A mutation and two known mutants R75P and R133C decreased NOTCH3 protein turnover and induced cell death.