Department of Medicine, Division of Endocrinology and Metabolism, University of Pittsburgh, Pittsburgh, Pennsylvania, USA.
Diabetes. 2012 Aug;61(8):2004-15. doi: 10.2337/db11-0802. Epub 2012 May 14.
Glucose stimulates rodent and human β-cell replication, but the intracellular signaling mechanisms are poorly understood. Carbohydrate response element-binding protein (ChREBP) is a lipogenic glucose-sensing transcription factor with unknown functions in pancreatic β-cells. We tested the hypothesis that ChREBP is required for glucose-stimulated β-cell proliferation. The relative expression of ChREBP was determined in liver and β-cells using quantitative RT-PCR (qRT-PCR), immunoblotting, and immunohistochemistry. Loss- and gain-of-function studies were performed using small interfering RNA and genetic deletion of ChREBP and adenoviral overexpression of ChREBP in rodent and human β-cells. Proliferation was measured by 5-bromo-2'-deoxyuridine incorporation, [(3)H]thymidine incorporation, and fluorescence-activated cell sorter analysis. In addition, the expression of cell cycle regulatory genes was measured by qRT-PCR and immunoblotting. ChREBP expression was comparable with liver in mouse pancreata and in rat and human islets. Depletion of ChREBP decreased glucose-stimulated proliferation in β-cells isolated from ChREBP(-/-) mice, in INS-1-derived 832/13 cells, and in primary rat and human β-cells. Furthermore, depletion of ChREBP decreased the glucose-stimulated expression of cell cycle accelerators. Overexpression of ChREBP amplified glucose-stimulated proliferation in rat and human β-cells, with concomitant increases in cyclin gene expression. In conclusion, ChREBP mediates glucose-stimulated proliferation in pancreatic β-cells.
葡萄糖刺激啮齿动物和人类β细胞的复制,但细胞内信号转导机制尚不清楚。碳水化合物反应元件结合蛋白(ChREBP)是一种脂生成葡萄糖感应转录因子,其在胰腺β细胞中的功能尚不清楚。我们检验了以下假设:ChREBP 是葡萄糖刺激β细胞增殖所必需的。使用定量 RT-PCR(qRT-PCR)、免疫印迹和免疫组织化学检测肝和β细胞中 ChREBP 的相对表达。使用小干扰 RNA 和 ChREBP 的基因缺失以及腺病毒过表达 ChREBP 在啮齿动物和人类β细胞中进行了失活和功能获得研究。通过 5-溴-2'-脱氧尿苷掺入、[(3)H]胸苷掺入和荧光激活细胞分选分析测量增殖。此外,通过 qRT-PCR 和免疫印迹测量细胞周期调节基因的表达。ChREBP 的表达与小鼠胰腺、大鼠和人胰岛中的肝脏相当。ChREBP 耗竭可降低 ChREBP(-/-)小鼠、INS-1 衍生的 832/13 细胞和原代大鼠和人β细胞中葡萄糖刺激的增殖。此外,ChREBP 的耗竭降低了葡萄糖刺激的细胞周期加速器的表达。ChREBP 的过表达放大了大鼠和人β细胞中葡萄糖刺激的增殖,同时 cyclin 基因的表达增加。总之,ChREBP 介导了胰腺β细胞中葡萄糖刺激的增殖。