Increasing GLP-1-induced β-cell proliferation by silencing the negative regulators of signaling cAMP response element modulator-α and DUSP14
Increasing GLP-1-induced β-cell proliferation by silencing the negative regulators of signaling cAMP response element modulator-α and DUSP14
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DOI：
10.2337/db07-1414
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发表时间：
2008-03-01
期刊：
影响因子：
7.7
通讯作者：
Thorens, Bernard
中科院分区：
文献类型：
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作者：
Klinger, Sonia;Poussin, Carine;Thorens, Bernard
胰高血糖素样肽-1（GLP-1）是成熟β细胞及其前体的生长和分化因子。然而，在体内和体外条件下，GLP-1对增加β-细胞质量的总体作用相对较小，增强这种作用将有利于治疗或预防1型和2型糖尿病。在这里，我们寻找可能限制GLP-1的增殖作用的细胞机制，并测试是否阻断它们可以增加P-cell proliferation.RESEARCH设计和方法-我们检查GLP-1调节基因在β TC-Tet细胞的cDNA ramicroarrays。为了评估这些基因中的一些对细胞增殖的影响，我们在P-细胞系和原代小鼠胰岛中使用小的异源RNA降低它们的表达，并测量[H-3]胸苷或5 ′-溴-2 ′-脱氧尿苷掺入。cAMP反应元件结合蛋白（CREB）拮抗剂cAMP反应元件调节剂（CREM）-α。和ICERI;和双特异性磷酸酶DUSP 14，一种丝裂原活化蛋白激酶（MAPK）/细胞外信号调节激酶1/2（ERK 1/2）途径的负调节剂。我们发现CREM α或DUSP 14的敲低或DUSP 14的显性负性形式的表达增加了P细胞系增殖并增强了GLP-1诱导的原代β细胞增殖。结论-总之，我们的数据表明1）cAMP/蛋白激酶A/CREB和MAPK/ERK 1/2途径可以相加地控制β细胞增殖，2）β-细胞已进化出几种限制GLP-1诱导的细胞增殖的机制，3）阻断这些机制可增加GLP-1对β-细胞群的积极作用。
OBJECTIVE-Glucagon-like peptide-1 (GLP-1) is a growth and differentiation factor for mature beta-cells and their precursors. However, the overall effect of GLP-1 on increasing beta-cell mass in both in vivo and in vitro conditions is relatively small, and augmenting this effect would be beneficial for the treatment or prevention of type 1 and type 2 diabetes. Here, we searched for cellular mechanisms that may limit the proliferative effect of GLP-1 and tested whether blocking them could increase P-cell proliferation.RESEARCH DESIGN AND METHODS-We examined GLP-1-regulated genes in beta TC-Tet cells by cDNA raicroarrays. To assess the effect of some of these gene on cell proliferation, we reduced their expression using small heterogenous RNA in P-cell lines and primary mouse islets and measured [H-3]thymidine or 5'-bromo-2'-deoxyuridine incorporation.RESULTS-We identified four negative regulators of intracellular signaling that were rapidly and strongly activated by GLP-1: the regulator of G-protein-signaling RGS2; the cAMP response element-binding protein (CREB) antagonists cAMP response element modulator (CREM)-alpha. and ICERI; and the dual specificity phosphatase DUSP14, a negative regulator of the mitogen-activated protein kinase (MAPK)/extracellular signal-regulated kinase 1/2 (ERK1/2) pathway. We show that knockdown of CREM alpha or DUSP14 or expression of a dominant-negative form of DUSP14 increased P-cell line proliferation and enhanced the GLP-1-induced proliferation of primary beta-cells.CONCLUSIONS-Together, our data show that 1) the cAMP/ protein kinase A/CREB and MAPK/ERK1/2 pathways can additively control beta-cell proliferation, 2) beta-cells have evolved several mechanisms limiting GLP-1-induced cellular proliferation, and 3) blocking these mechanisms increases the positive effect of GLP-1 on beta-cell mass.