IGF-I Stimulates CCN5/WISP2 Gene Expression in Pancreatic β-Cells, Which Promotes Cell Proliferation and Survival Against Streptozotocin
IGF-I Stimulates CCN5/WISP2 Gene Expression in Pancreatic β-Cells, Which Promotes Cell Proliferation and Survival Against Streptozotocin
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IGF-I 刺激胰腺 β 细胞中的 CCN5/WISP2 基因表达，从而促进细胞增殖和抵抗链脲佐菌素的存活
DOI：
10.1210/en.2013-1735
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发表时间：
2014-05-01
期刊：
影响因子：
4.8
通讯作者：
Liu, Jun-Li
中科院分区：
文献类型：
--
作者：
Chowdhury, Subrata;Wang, Xiao;Liu, Jun-Li
IGF-I通常是由肝细胞和其他来源产生的，刺激蛋白质合成，细胞存活和通过受体介导的磷脂酰肌醇3-激酶和MAPK的激活，并靶向胰岛胰岛细胞内的特定分子。当前的研究旨在识别可能介导其亲ISLET作用的新颖目标。在IGF-I-I-I-Ever表达胰岛中，全基因组cDNA微阵列分析被鉴定出82个基因，特异性上调或下调。其中突出的是CCN5/WISP2，其表达在mRNA和蛋白质水平上增加了3-和2倍。双标记的免疫荧光表明，野生型胰岛的β细胞中CCN5表达较低，但对IGF-I过表达的响应显着诱导。 IGF-1的小鼠胰岛的体外处理显着升高了CCN5 mRNA和蛋白质水平。为了定义CCN5在胰岛细胞生物学中的作用，我们在胰岛素瘤MIN6细胞中稳定地过表达其cDNA，并且与对照细胞中的Min6-CCN5相比，MIN6-CCN5的增殖增加了2倍，这与Cyclin D1和Akt和Erk2的磷酸化水平的显着升高相关。此外，发现MIN6-CCN5细胞对链蛋白酶诱导的细胞死亡具有抗性。使用共聚焦显微镜和亚细胞分馏，我们发现过表达的CCN5在高葡萄糖刺激后表现出细胞质积累。我们的结果表明，在胰岛β细胞中最小表达的CCN5强烈地由IGF-I诱导。 CCN5的过表达刺激胰岛素瘤细胞的增殖，激活Akt激酶并抑制链蛋白酶诱导的凋亡，这表明CCN5表达的增加有助于IGF-I刺激的胰岛细胞的生长和/或生存。
IGF-I is normally produced from hepatocytes and other sources, stimulates protein synthesis, cell survival, and proliferation through receptor-mediated activation of phosphatidylinositol 3-kinase and MAPK, and targets specific molecules within the pancreatic islet cells. The current study was designed to identify novel targets that may mediate its pro-islet actions. Whole-genome cDNA microarray analysis in IGF-I-overexpressing islets identified 82 genes specifically up- or down-regulated. Prominent among them was CCN5/WISP2 whose expression was increased 3- and 2-fold at the mRNA and protein levels. Dual-labeled immunofluorescence revealed that CCN5 expression was low in the beta-cells of wild-type islets but was significantly induced in response to IGF-I overexpression. In vitro treatment of mouse islets with IGF-I increased both CCN5 mRNA and protein levels significantly. To define the role of CCN5 in islet cell biology, we stably overexpressed its cDNA in insulinoma MIN6 cells and detected a 2-fold increase in the proliferation of MIN6-CCN5 compared with that in control cells, which correlated with significant elevations in the levels of cyclin D1 and the phosphorylation of Akt and Erk2. Moreover, MIN6-CCN5 cells were found to be resistant to streptozotocin-induced cell death. Using confocal microscopy and subcellular fractionation, we found that overexpressed CCN5 exhibited cytoplasmic accumulation upon stimulation by high glucose. Our results indicate that CCN5, which is minimally expressed in islet beta-cells, is strongly and directly induced by IGF-I. CCN5 overexpression stimulates the proliferation of insulinoma cells, activates Akt kinase, and inhibits streptozotocin-induced apoptosis, suggesting that increased CCN5 expression contributes to IGF-I-stimulated islet cell growth and/or survival.