Mice conditionally lacking the Wolfram gene in pancreatic islet beta cells exhibit diabetes as a result of enhanced endoplasmic reticulum stress and apoptosis
Mice conditionally lacking the Wolfram gene in pancreatic islet beta cells exhibit diabetes as a result of enhanced endoplasmic reticulum stress and apoptosis
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DOI：
10.1007/s00125-005-1947-4
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发表时间：
2005-11-01
期刊：
影响因子：
8.2
通讯作者：
Permutt, MA
中科院分区：
文献类型：
--
作者：
Riggs, AC;Bernal-Mizrachi, E;Permutt, MA
目的/假设：Wolfram综合征是一种常染色体隐性遗传疾病，其特征是儿童糖尿病、视神经萎缩和严重的神经变性，导致过早死亡。本研究的目的是调查在这种疾病中负责碳水化合物不耐受和胰腺β细胞损失的表型的机制。材料与方法：为了研究Wolfram基因（Wfs 1）在β细胞中的作用，我们通过将floxed Wfs 1外显子8动物与在大鼠胰岛素启动子（RIP 2-Cre）控制下表达Cre重组酶的小鼠杂交，建立了β细胞中Wfs 1条件性缺失的小鼠模型。在小鼠胰岛素瘤（MIN 6）细胞系（WfsKD）中进行了使用Wfs 1表达的RNA干扰的补充实验。结果如下：与同窝对照组相比，雄性基因敲除小鼠（β Wfs（-/-））在12周龄时开始出现可变和进行性葡萄糖耐受不良以及伴随的胰岛素缺乏。β Wfs（-/-）小鼠胰岛分析显示β细胞质量减少，细胞凋亡增强，内质网应激标志物（免疫球蛋白重链结合蛋白[BiP]）升高，内质网扩张，电子显微镜下分泌颗粒减少。WfsKD细胞系具有显著增加的细胞凋亡和升高的编码BiP和C/EBP同源蛋白（CHOP）的基因表达，这两种内质网应激的标志物。结论/解释：这些结果表明：（1）β细胞中Wfs 1表达的缺乏足以导致糖尿病表型;（2）β细胞死亡是通过细胞凋亡的加速过程发生的;（3）Wfs 1的缺乏与内质网扩张和内质网应激标志物增加有关，这似乎是β细胞存活减少的重要原因。
Aims/hypothesis: Wolfram syndrome is an autosomal recessive disorder characterised by childhood diabetes mellitus, optic atrophy and severe neurodegeneration, resulting in premature death. The aim of this study was to investigate the mechanisms responsible for the phenotype of carbohydrate intolerance and loss of pancreatic beta cells in this disorder. Materials and methods: To study the role of the Wolfram gene (Wfs1) in beta cells, we developed a mouse model with conditional deletion of Wfs1 in beta cells by crossing floxed Wfs1 exon 8 animals with mice expressing Cre recombinase under the control of a rat insulin promoter (RIP2-Cre). Complementary experiments using RNA interference of Wfs1 expression were performed in mouse insulinoma (MIN6) cell lines (WfsKD). Results: Male knockout mice (beta Wfs(-/-)) began developing variable and progressive glucose intolerance and concomitant insulin deficiency, compared with littermate controls, by 12 weeks of age. Analysis of islets from beta Wfs(-/-) mice revealed a reduction in beta cell mass, enhanced apoptosis, elevation of a marker of endoplasmic reticulum stress (immunoglobulin heavy chain-binding protein [BiP]), and dilated endoplasmic reticulum with decreased secretory granules by electron microscopy. WfsKD cell lines had significantly increased apoptosis and elevated expression of the genes encoding BiP and C/EBP-homologous protein (CHOP), two markers of endoplasmic reticulum stress. Conclusions/interpretation: These results indicate that (1) lack of expression of Wfs1 in beta cells was sufficient to result in the diabetes mellitus phenotype; (2) beta cell death occurred by an accelerated process of apoptosis; and (3) lack of Wfs1 was associated with dilated endoplasmic reticulum and increased markers of endoplasmic reticulum stress, which appears to be a significant contributor to the reduction in beta cell survival.