Details

Autor(en) / Beteiligte

• Zmuda, Erik J
• Qi, Ling
• Zhu, Michael X
• Mirmira, Raghavendra G
• Montminy, Marc R
• Hai, Tsonwin

Titel

The Roles of ATF3, an Adaptive-Response Gene, in High-Fat-Diet-Induced Diabetes and Pancreatic β-Cell Dysfunction

Ist Teil von

• Molecular endocrinology (Baltimore, Md.), 2010-07, Vol.24 (7), p.1423-1433

Ort / Verlag

United States: Endocrine Society

Erscheinungsjahr

2010

Link zum Volltext

Quelle

Alma/SFX Local Collection

Beschreibungen/Notizen

• Most people with type 2 diabetes (T2D) have reduced β-cell mass, and apoptosis is a key factor for this reduction. Previously, we showed that ATF3, an adaptive-response gene, is induced by various stress signals relevant to T2D, such as high glucose and high fatty acid. Because ATF3 is proapoptotic in β-cells, we tested the hypothesis that ATF3 plays a detrimental role and contributes to the development of T2D. We compared wild-type (WT) and ATF3 knockout (KO) mice in an animal model for T2D, high-fat diet-induced diabetes. We also used INS-1 β-cells and primary islets to analyze the roles of ATF3 in β-cell function, including insulin gene expression and glucose-induced insulin secretion. Surprisingly, WT mice performed better in glucose tolerance test than KO mice, suggesting a protective, rather than detrimental, role of ATF3. At 12 wk on high-fat diet, no β-cell apoptosis was observed, and the WT and KO mice had comparable β-cell areas. However, ATF3 deficiency significantly reduced serum insulin levels in the KO mice without affecting insulin sensitivity, suggesting reduced β-cell function in the KO mice. Analyses using INS-1 cells and primary islets support the notion that this defect is due, at least partly, to reduced insulin gene transcription in the KO islets without detectable reduction in glucose-induced calcium influx, a critical step for insulin secretion. In conclusion, our results support a model in which, before apoptosis becomes obvious, expression of ATF3 can be beneficial by helping β-cells to cope with higher metabolic demand. This report presents evidence that ATF3, a stress-inducible pro-apoptotic gene, up-regulates insulin gene expression and can thus help β-cells to cope with higher metabolic demand.