Department of Endocrinology, The First Affiliated Hospital of Sun Yat-sen University, 58 Zhongshan Road 2, Guangzhou, 510080, P. R. China.
Department of Geriatrics, The First Affiliated Hospital of Sun Yat-sen University, Guangzhou, 510080, Guangdong, China.
BMC Endocr Disord. 2021 Apr 21;21(1):76. doi: 10.1186/s12902-021-00748-z.
Wolfram syndrome (WS) is a rare autosomal recessive disorder characterized by diabetes insipidus, diabetes mellitus, optic atrophy and deafness. Mutations in Wolfram syndrome 1 (WFS1) gene may cause dysregulated endoplasmic reticulum (ER)-stress and cell apoptosis, contributing to WS symptoms. The aim of this study was to identify the molecular etiology of a case of WS and to explore the functional consequence of the mutant WFS1 gene in vitro.
A 27 years-old Chinese man was diagnosed as wolfram syndrome type 1 based on clinical data and laboratory data. DNA sequencing of WFS1 gene and mitochondrial m.3337G > A, m.3243A > G mutations were performed in the patient and his 4 family members. Functional analysis was performed to assessed the in vitro effect of the newly identified mutant. ER stress were evaluated by ER stress response element (ERSE)-luciferase assay. Cell apoptosis were performed by CCK-8, TUNEL staining and flow cytometric analysis.
A novel heterozygous 10-base deletion (c. 2067_2076 del10, p.W690fsX706) was identified in the patient. In vitro studies showed that mutant p.W690fsX706 increased ERSE reporter activity in the presence or absence of thapsigargin instead of wild type WFS1. Knockdown of WFS1 activated the unfolded protein response (UPR) pathway and increased the cell apoptosis, which could not be restored by transfection with WFS1 mutant (p.W690fsX706) comparable to the wild type WFS1.
A novel heterozygous mutation of WFS1 detected in the patient resulted in loss-of-function of wolframin, thereby inducing dysregulated ER stress signaling and cell apoptosis. These findings increase the spectrum of WFS1 gene mutations and broaden our insights into the roles of mutant WFS1 in the pathogenesis of WS.
Wolfram 综合征（WS）是一种罕见的常染色体隐性遗传病，其特征为尿崩症、糖尿病、视神经萎缩和耳聋。Wolfram 综合征 1 型（WFS1）基因突变可能导致内质网（ER）应激和细胞凋亡失调，导致 WS 症状。本研究旨在确定一例 WS 的分子病因，并探讨体外突变 WFS1 基因的功能后果。
根据临床和实验室数据，对一名 27 岁的中国男性患者诊断为 WS 1 型。对患者及其 4 名家族成员的 WFS1 基因和线粒体 m.3337G> A、m.3243A> G 突变进行 DNA 测序。进行功能分析以评估新鉴定的突变体的体外效应。通过 ER 应激反应元件（ERSE）-荧光素酶测定评估 ER 应激。通过 CCK-8、TUNEL 染色和流式细胞术分析评估细胞凋亡。
在患者中发现了一个新的杂合 10 碱基缺失（c.2067_2076del10，p.W690fsX706）。体外研究表明，突变体 p.W690fsX706 在存在或不存在他普西啶的情况下增加了 ERSE 报告基因的活性，而不是野生型 WFS1。WFS1 的敲低激活了未折叠蛋白反应（UPR）通路并增加了细胞凋亡，但用 WFS1 突变体（p.W690fsX706）转染不能恢复，与野生型 WFS1 相比。
在患者中检测到的 WFS1 新型杂合突变导致 wolframin 功能丧失，从而导致 ER 应激信号和细胞凋亡失调。这些发现增加了 WFS1 基因突变谱，并拓宽了我们对突变型 WFS1 在 WS 发病机制中的作用的认识。
