Endoplasmic reticulum stress induces Wfs1 gene expression in pancreatic β-cells via transcriptional activation
Endoplasmic reticulum stress induces Wfs1 gene expression in pancreatic β-cells via transcriptional activation
复制标题
DOI：
10.1530/eje.1.01945
复制
发表时间：
2005-07-01
影响因子：
5.8
通讯作者：
Tanizawa, Y
中科院分区：
文献类型：
--
作者：
Ueda, K;Kawano, J;Tanizawa, Y
目的：WFS 1基因编码一种内质网（ER）膜包埋蛋白。纯合子WFS 1基因突变导致Wolfram综合征，其特征是胰岛素缺乏型糖尿病和视神经萎缩。胰腺β细胞选择性地从患者的胰岛中丢失。内质网定位表明，WFS 1蛋白在膜运输，分泌，加工和/或调节内质网钙稳态的生理功能。这些功能的干扰或过载诱导ER应激反应，包括细胞凋亡。我们推测Wfs 1蛋白可能参与了这些内质网应激反应。设计和方法：免疫组化分析Wfs 1蛋白在胰岛中的表达。通过北方和Western印迹分析，使用三种不同的模型：人皮肤成纤维细胞、小鼠胰腺β细胞衍生的MIN 6细胞和秋田小鼠衍生的Ins 2（96 Y/Y）胰岛素瘤细胞，检测ER应激时Wfs 1的诱导。结果：胰岛β细胞是Wfs 1基因表达的主要部位。这种表达也在δ细胞中发现，但在α细胞中没有。WFS 1的表达上调ER应激诱导的化学损伤。用毒胡萝卜素或衣霉素处理成纤维细胞和M1 N6细胞增加了WFS 1 mRNA。在这些细胞中，WFS 1蛋白也响应于毒胡萝卜素处理而增加。在Ins 2（96 Y/Y）胰岛素瘤细胞中，WFS 1基因表达也明显增加。在这些细胞中，内质网应激本质上是由突变型胰岛素表达诱导的。WFS 1基因启动子-荧光素酶报告系统显示，在MIN 6细胞中，人WFS 1启动子被化学诱导的ER应激激活，并且该启动子在Ins 2（96 Y/Y）细胞中比Ins 2更有活性结论：定位于胰岛β细胞和δ细胞的Wfs 1表达响应于ER应激而增加，提示Wfs 1和ER应激之间存在功能联系。
Objective: The WFS1 gene encodes an endoplasmic reticulum (ER) membrane-embedded protein. Homozygous WFS1 gene mutations cause Wolfram syndrome, characterized by insulin-deficient diabetes mellitus and optic atropy. Pancreatic beta-cells are selectively lost from the patient's islets. ER localization suggests that WFS1 protein has physiological functions in membrane trafficking, secretion, processing and/or regulation of ER calcium homeostasis. Disturbances or overloading of these functions induces ER stress responses, including apoptosis. We speculated that WFS1 protein might be involved in these ER stress responses.Design and methods: Islet expression of the Wfs1 protein was analyzed immunohistochemically. Induction of Wfs1 upon ER stress was examined by Northern and Western blot analyses using three different models: human skin fibroblasts, mouse pancreatic beta-cell-derived MIN6 cells, and Akita mouse-derived Ins2(96Y/Y) insulinoma cells. The human WFS I gene promoter-luciferase reporter analysis was also conducted.Result: Islet beta-cells were the major site of Wfs1 expression. This expression was also found in delta-cells, but not in alpha-cells. WFS1 expression was transcriptionally up-regulated by ER stress-inducing chemical insults. Treatment of fibroblasts and MlN6 cells with thapsigargin or tunicamycin increased WFS1 mRNA. WFS1 protein also increased in response to thapsigargin treatment in these cells. WFS1 gene expression was also increased in Ins2(96Y/Y) insulinoma cells. In these cells, ER stress was intrinsically induced by mutant insulin expression. The WFS1 gene promoter-luciferase reporter system revealed that the human WFS1 promoter was activated by chemically induced ER stress in MIN6 cells, and that the promoter was more active in Ins2(96Y/Y) cells than Ins2(wild/wild) cells.Conclusion: Wfs1 expression, which is localized to beta- and delta-cells in pancreatic islets, increases in response to ER stress, suggesting a functional link between Wfs1 and ER stress.