Insulin increases tristetraprolin and decreases VEGF gene expression in mouse 3T3-L1 adipocytes
Insulin increases tristetraprolin and decreases VEGF gene expression in mouse 3T3-L1 adipocytes
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DOI：
10.1038/oby.2008.65
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发表时间：
2008-06-01
期刊：
影响因子：
6.9
通讯作者：
Anderson, Richard A.
中科院分区：
文献类型：
--
作者：
Cao, Heping;Urban, Joseph F., Jr.;Anderson, Richard A.
目的：Tristetraprolin（TTP）家族蛋白（TTP/ZFP 36; ZFP 36 L1、ZFP 36 L2、ZFP 36 L3）使编码细胞因子（如肿瘤坏死因子（TNF）和血管内皮生长因子（VEGF））的含腺苷酸尿苷酸富集元素的mRNA不稳定。关于TTP及其相关基因在脂肪细胞中的表达和胰岛素调控的研究还很少。我们分析了TTP家族mRNA在3 T3-L1脂肪细胞中的相对丰度与RAW264.7巨噬细胞相比，并研究了胰岛素对3 T3-L1脂肪细胞中43个基因表达的影响。通过定量实时PCR测定mRNA水平的相对丰度。结果：Zfp 36 l1和Zfp 36 l2基因在脂肪细胞中的表达量是Ttp基因的8 ~ 10倍。在脂肪细胞中检测到Zfp 36 l3 mRNA的水平与Ttp mRNA的1%相似，并且在RAW细胞中证实了其低水平表达。胰岛素在10和100 nmol/l增加Ttp mRNA水平的五至七倍，但减少了40%的Zfp 36 l3在脂肪细胞30分钟的治疗后。免疫印迹显示胰岛素诱导TTP，但不影响脂肪细胞中ZFP 36 L1蛋白水平。胰岛素降低脂肪细胞中VEGF和其他一些基因的mRNA水平。讨论：胰岛素诱导脂肪细胞中Ttp mRNA和蛋白的表达，并降低VEGF mRNA水平。首次在小鼠胎盘和胚外组织以外的细胞中检测到Zfp 36 l3 mRNA。本研究为探讨TTP和VEGF基因在肥胖调控中的作用奠定了基础，并提示VEGF mRNA可能是TTP在脂肪细胞中的作用靶点。
Objectives: Tristetraprolin (TTP) family proteins (TTP/ZFP36; ZFP36L1, ZFP36L2, ZFP36L3) destabilize adenylate uridylate-rich element-containing mRNAs encoding cytokines, such as tumor necrosis factor (TNF) and vascular endothelial growth factor (VEGF). Little is known about the expression and insulin regulation of TTP and related genes in adipocytes. We analyzed the relative abundance of TTP family mRNAs in 3T3-L1 adipocytes compared to RAW264.7 macrophages and investigated insulin effects on the expression of 43 genes in 3T3-L1 adipocytes.Methods and Procedures: Insulin was added to mouse 3T3-L1 adipocytes. Relative abundance of mRNA levels was determined by quantitative real-time PCR. TTP and ZFP36L1 proteins were detected by immunoblotting.Results: Zfp36l1 and Zfp36l2 genes were expressed at eight- to tenfold higher than Ttp in adipocytes. Zfp36l3 mRNA was detected at similar to 1% of Ttp mRNA levels in adipocytes and its low level expression was confirmed in RAW cells. Insulin at 10 and 100 nmol/l increased Ttp mRNA levels by five- to sevenfold, but decreased those of Zfp36l3 by 40% in adipocytes after a 30-min treatment. Immunoblotting showed that insulin induced TTP but did not affect ZFP36L1 protein levels in adipocytes. Insulin decreased mRNA levels of Vegf and a number of other genes in adipocytes.Discussion: Insulin induced Ttp mRNA and protein expression and decreased Vegf mRNA levels in adipocytes. Zfp36l3 mRNA was detected, for the first time, in cells other than mouse placenta and extraembryonic tissues. This study established a basis for the investigation of TTP and VEGF genes in the regulation of obesity and suggested that Vegf mRNA may be a target of TTP in fat cells.