Lee Yong-Soo, Kobayashi Masaki, Kikuchi Osamu, Sasaki Tsutomu, Yokota-Hashimoto Hiromi, Susanti Vina Yanti, Ido Kitamura Yukari, Kitamura Tadahiro
Metabolic Signal Research Center, Institute for Molecular and Cellular Regulation, Gunma University, Maebashi, Gunma, Japan.
Endocr J. 2014;61(1):85-90. doi: 10.1507/endocrj.ej13-0383. Epub 2013 Oct 20.
The pancreas is critical for maintaining glucose homeostasis. Activating transcription factor 3 (ATF3) is an adaptive response transcription factor. There are major discrepancies in previous reports on pancreatic ATF3; therefore, its role in the pancreas is unclear. To better elucidate the role of ATF3 in the pancreas, we conducted in vitro studies using pancreatic α and β cell lines, and also evaluated the use of ATF3 antibodies for immunohistochemistry. We determined ATF3 expression was increased by low glucose and decreased by high glucose in both αTC-1.6 and βTC3 cells. We also showed that adenovirus-mediated ATF3 overexpression increased glucagon promoter activity and glucagon mRNA levels in αTC-1.6 cells; whereas, it had no effect on insulin promoter activity and insulin mRNA levels in βTC3 cells. Although immunostaining with the C-19 ATF3 antibody demonstrated predominant expression in α cells rather than β cells, ATF3 staining was still detected in ATF3 knockout mice as clearly as in control mice. On the other hand, another ATF3 antibody (H-90) detected ATF3 in both α cells and β cells, and was clearly diminished in ATF3 knockout mice. These results indicate that previous discrepancies in ATF3 expression patterns in the pancreas were caused by the varying specificities of the ATF3 antibodies used, and that ATF3 is actually expressed in both α cells and β cells.
胰腺对于维持葡萄糖稳态至关重要。激活转录因子3（ATF3）是一种适应性反应转录因子。先前关于胰腺ATF3的报道存在重大差异；因此，其在胰腺中的作用尚不清楚。为了更好地阐明ATF3在胰腺中的作用，我们使用胰腺α和β细胞系进行了体外研究，并评估了ATF3抗体在免疫组织化学中的应用。我们确定在αTC-1.6和βTC3细胞中，低葡萄糖会增加ATF3表达，高葡萄糖会降低ATF3表达。我们还表明，腺病毒介导的ATF3过表达会增加αTC-1.6细胞中胰高血糖素启动子活性和胰高血糖素mRNA水平；而对βTC3细胞中的胰岛素启动子活性和胰岛素mRNA水平没有影响。尽管用C-19 ATF3抗体进行免疫染色显示在α细胞而非β细胞中主要表达，但在ATF3基因敲除小鼠中仍能像在对照小鼠中一样清楚地检测到ATF3染色。另一方面，另一种ATF3抗体（H-90）在α细胞和β细胞中均检测到ATF3，且在ATF3基因敲除小鼠中明显减少。这些结果表明，先前胰腺中ATF3表达模式的差异是由所用ATF3抗体的不同特异性引起的，并且ATF3实际上在α细胞和β细胞中均有表达。
