Clock Gene Dysregulation Induced by Chronic ER Stress Disrupts β-cell Function

EBioMedicine

Yasuharu Ohta¹  Masaru Akiyama¹  Ruriko Fujimoto¹  Hiroko Nakabayashi¹  Yukio Tanizawa¹  Kaoru Yamamoto¹  Takuro Matsumura¹  Risa Suetomi¹  Akihiko Taguchi¹  Koh Shinoda²  Akie Yanai² 

[1] Department of Endocrinology, Metabolism, Hematological Science and Therapeutics, Yamaguchi University, Graduate School of Medicine, 1-1-1, Minami Kogushi, Ube, Yamaguchi 755-8505, Japan;Department of Neuroanatomy, Yamaguchi University, Graduate School of Medicine, 1-1-1, Minami Kogushi, Ube, Yamaguchi 755-8505, Japan;

关键词: Endoplasmic reticulum stress;    Clock out-put gene;    Diabetes mellitus;    Pancreatic islet β-cell;    Insulin secretion;   

DOI  :  10.1016/j.ebiom.2017.03.040

来源: DOAJ

【 摘 要 】

In Wfs1−/− Ay/a islets, in association with endoplasmic reticulum (ER) stress, D-site-binding protein (Dbp) expression decreased and Nuclear Factor IL-3 (Nfil3)/E4 Promoter-binding protein 4 (E4bp4) expression increased, leading to reduced DBP transcriptional activity. Similar alterations were observed with chemically-induced ER stress. Transgenic mice expressing E4BP4 under the control of the mouse insulin I gene promoter (MIP), in which E4BP4 in β-cells is expected to compete with DBP for D-box, displayed remarkable glucose intolerance with severely impaired insulin secretion. Basal ATP/ADP ratios in MIP-E4BP4 islets were elevated without the circadian oscillations observed in wild-type islets. Neither elevation of the ATP/ADP ratio nor an intracellular Ca2+ response was observed after glucose stimulation. RNA expressions of genes involved in insulin secretion gradually increase in wild-type islets early in the feeding period. In MIP-E4BP4 islets, however, these increases were not observed. Thus, molecular clock output DBP transcriptional activity, susceptible to ER stress, plays pivotal roles in β-cell priming for insulin release by regulating β-cell metabolism and gene expressions. Because ER stress is also involved in the β-cell failure in more common Type-2 diabetes, understanding the currently identified ER stress-associated mechanisms warrants novel therapeutic and preventive strategies for both rare form and common diabetes.

【 授权许可】

Unknown