Novel UMOD mutations in familial juvenile hyperuricemic nephropathy lead to abnormal uromodulin intracellular trafficking
Novel UMOD mutations in familial juvenile hyperuricemic nephropathy lead to abnormal uromodulin intracellular trafficking
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家族性青少年高尿酸血症肾病中的新 UMOD 突变导致尿调节素细胞内运输异常
DOI：
10.1016/j.gene.2013.08.041
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发表时间：
2013-12-01
期刊：
影响因子：
3.5
通讯作者：
Zhao, Minghui
中科院分区：
文献类型：
--
作者：
Liu, Maojing;Chen, Yuqing;Zhao, Minghui
背景：家族性青少年高尿酸血症肾病（FJHN）是一种常染色体显性遗传病，以高尿酸血症和进行性慢性肾脏疾病为特征。尿调素基因（UMOD）突变导致尿调素在细胞内转运异常，有助于疾病的发展。方法：对3个中国FJHN家族进行UMOD筛查。利用野生型尿调素载体，通过定点诱变构建尿调素突变表达质粒，并将其转染人胚胎肾细胞HEK293。western blot法检测尿调蛋白表达，免疫荧光法观察细胞内分布。结果：发现3个杂合突变。突变Val109Glu （c.326T/A; p.Val109Glu）和突变Pro236Gln （c.707C/A; p.Pro236GIn）是在两个不同家族（F1家族和F3家族）中新发现的突变。另一个先前报道的UMOD突变Cys248Trp （c744C/G; p.Cys248Trp）在F2家族中被检测到。表型在同一家族内部和不同家族之间都存在差异。患者活检显示尿调蛋白表达异常。突变的功能分析表明，突变型尿调蛋白分泌到上清培养基中比野生型少得多。在突变型尿调素转染的细胞中，细胞内尿调素在高尔基体中的定位较少，在内质网（ER）中的定位较多。结论：我们的研究结果表明，在中国家族中发现的新型尿调蛋白突变导致蛋白质错误折叠，并保留在内质网中，最终导致了FJHN的表型。(C) 2013 Elsevier B.V.版权所有
Background: Familial juvenile hyperuricemic nephropathy (FJHN) is an autosomal dominant disorder characterized by hyperuricemia and progressive chronic kidney disease. Uromodulin gene (UMOD) mutations, leading to abnormalities of uromodulin intracellular trafficking contribute to the progress of the disease.Methods: We did UMOD screening in three Chinese FJHN families. We thus constructed mutant uromodulin express plasmids by site-mutagenesis from wild type uromodulin vector and transfected them into HEK293 (human embryonic kidney) cells. And then we detected uromodulin expression by western blot and observed intracellular distribution by immunofluorescence.Results: We found three heterozygous mutations. Mutation Val109Glu (c.326T/A; p.Val109Glu) and mutation Pro236Gln (c.707C/A; p.Pro236GIn) were newly indentified mutations in two distinct families (family F1 and family F3). Another previously reported UMOD mutation Cys248Trp (c744C/G; p.Cys248Trp) was detected in family F2. Phenotypes varied both within the same family and between different families. Uromodulin expression is abnormal in the patient biopsy. Functional analysis of mutation showed that mutant types of uromodulin were secreted into the supernatant medium much less when compared with wild type. In mutant type uromodulin transfected cells, intracellular uromodulin localized less in the Golgi apparatus and more in endoplasmic reticulum(ER).Conclusions: Our results suggested that the novel uromodulin mutations found in the Chinese families lead to misfolded protein, which was retained in the endoplasmic reticulum, finally contributed to the phenotype of FJHN. (C) 2013 Elsevier B.V. All rights reserved.