ATF4-mediated transcriptional regulation protects against β-cell loss during endoplasmic reticulum stress in a mouse model.
ATF4-mediated transcriptional regulation protects against β-cell loss during endoplasmic reticulum stress in a mouse model.
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DOI：
10.1016/j.molmet.2021.101338
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发表时间：
2021-12
影响因子：
8.1
通讯作者：
Oyadomari S
中科院分区：
文献类型：
--
作者：
Kitakaze K;Oyadomari M;Zhang J;Hamada Y;Takenouchi Y;Tsuboi K;Inagaki M;Tachikawa M;Fujitani Y;Okamoto Y;Oyadomari S
激活转录因子4 （ATF4）是未折叠蛋白反应和综合应激反应（ISR）的转录调节因子，促进正常内质网（ER）功能的恢复。先前的报告表明，ISR的失调会导致严重糖尿病的发展。然而，ATF4对胰腺β细胞的作用仍然知之甚少。在本研究中，我们旨在分析ISR增强子Sephin1和ATF4缺陷β-细胞的作用，以阐明内质网应激条件下ATF4在β-细胞中的作用。为了研究ATF4在体内的作用，每天给秋田小鼠注射ISR增强剂Sephin1 (5 mg/kg体重，p.o)，持续21天。我们还建立了β细胞特异性Atf4敲除（βAtf4-KO）小鼠，并与秋田小鼠进一步杂交。分析这些小鼠的糖尿病特征、β细胞功能和胰岛形态。为了确定β-细胞中ATF4的下游因子，我们对βAtf4-KO小鼠的胰岛进行了cDNA芯片分析。为了检验ATF4的转录调控作用，我们还对小鼠胰腺切片进行了原位PCR分析，并对CT215 β-细胞进行了ChIP-qPCR分析。ISR增强剂Sephin1可改善秋田小鼠的葡萄糖代谢。Sephin1也增加了胰岛中胰岛素免疫阳性区域和ATF4的表达。秋田/βAtf4-KO小鼠表现出显著加重的糖尿病，表现为早期高血糖，以及由于糖尿病酮症酸中毒而显着缩短的寿命。此外，秋田/βAtf4-KO小鼠胰岛胰高血糖素、生长抑素和胰多肽染色细胞数量增加，醛脱氢酶1家族成员3（去分化标志物）表达增加。通过微阵列分析，我们发现无调性BHLH转录因子8 （ATOH8）是ATF4的下游因子。在β-细胞中，ATF4的缺失导致Atoh8的表达减少，未分化标记物Nanog和Pou5f1的表达增加。Atoh8在秋田/βAtf4-KO小鼠胰岛中的表达也被消除。我们得出结论，ATF4的转录调节通过ISR调节维持β细胞的特性。这一机制为糖尿病的治疗提供了一个有希望的靶点。ISR增强剂Sephin1改善糖尿病秋田小鼠的葡萄糖代谢。Atf4的β细胞特异性缺失促进了秋田小鼠β细胞的丢失。ATOH8的下调增强了β-细胞的不分化。
Activating transcription factor 4 (ATF4) is a transcriptional regulator of the unfolded protein response and integrated stress response (ISR) that promote the restoration of normal endoplasmic reticulum (ER) function. Previous reports demonstrated that dysregulation of the ISR led to development of severe diabetes. However, the contribution of ATF4 to pancreatic β-cells remains poorly understood. In this study, we aimed to analyze the effect of ISR enhancer Sephin1 and ATF4-deficient β-cells to clarify the role of ATF4 in β-cells under ER stress conditions. To examine the role of ATF4 in vivo, ISR enhancer Sephin1 (5 mg/kg body weight, p.o.) was administered daily for 21 days to Akita mice. We also established β-cell–specific Atf4 knockout (βAtf4-KO) mice that were further crossed with Akita mice. These mice were analyzed for characteristics of diabetes, β-cell function, and morphology of the islets. To identify the downstream factors of ATF4 in β-cells, the islets of βAtf4-KO mice were subjected to cDNA microarray analyses. To examine the transcriptional regulation by ATF4, we also performed in situ PCR analysis of pancreatic sections from mice and ChIP-qPCR analysis of CT215 β-cells. Administration of the ISR enhancer Sephin1 improved glucose metabolism in Akita mice. Sephin1 also increased the insulin-immunopositive area and ATF4 expression in the pancreatic islets. Akita/βAtf4-KO mice exhibited dramatically exacerbated diabetes, shown by hyperglycemia at an early age, as well as a remarkably short lifespan owing to diabetic ketoacidosis. Moreover, the islets of Akita/βAtf4-KO mice presented increased numbers of cells stained for glucagon, somatostatin, and pancreatic polypeptide and increased expression of aldehyde dehydrogenase 1 family member 3, a marker of dedifferentiation. Using microarray analysis, we identified atonal BHLH transcription factor 8 (ATOH8) as a downstream factor of ATF4. Deletion of ATF4 in β-cells showed reduced Atoh8 expression and increased expression of undifferentiated markers, Nanog and Pou5f1. Atoh8 expression was also abolished in the islets of Akita/βAtf4-KO mice. We conclude that transcriptional regulation by ATF4 maintains β-cell identity via ISR modulation. This mechanism provides a promising target for the treatment of diabetes. ISR enhancer Sephin1 improved glucose metabolism in diabetic Akita mice. β-Cell-specific deletion of Atf4 promoted β-cell loss in Akita mice. Downregulation of ATOH8 enhances the undifferentiation of β-cells.
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DOI：
10.1126/science.aaa4484
发表时间：
2015-04-10
期刊：
Science (New York, N.Y.)
影响因子：
--
作者：
Das I;Krzyzosiak A;Schneider K;Wrabetz L;D'Antonio M;Barry N;Sigurdardottir A;Bertolotti A
通讯作者：
Bertolotti A
影响因子：
21.3
作者：
通讯作者：
--
人类胰岛素基因的七种突变与永久性新生儿/婴幼儿糖尿病有关
影响因子：
15.9
作者：
Colombo, Carlo;Porzio, Ottavia;Barbetti, Fabrizio
通讯作者：
Barbetti, Fabrizio
影响因子：
29
作者：
Back SH;Scheuner D;Han J;Song B;Ribick M;Wang J;Gildersleeve RD;Pennathur S;Kaufman RJ
通讯作者：
Kaufman RJ
影响因子：
3.7
作者：
Hunter CS;Stein RW
通讯作者：
Stein RW