MACROPHAGE ENDOGENOUS FACTOR THAT SUPPRESSES ANABOLISM

我们一直在研究肿瘤坏死因子-α（TNF） 对3 T3-L1中分解代谢状态的诱导和调节 成纤维细胞 我们的兴趣一直集中在监管 在葡萄糖进入细胞的关键步骤的细胞营养。 我们的数据支持这样的假设，即TNF，让人联想到血清来源的 生长因子，提高葡萄糖转运活性以及 3 T3-L1细胞中GLUT 1 mRNA的表达 内在GLUT活性，预先存在的转运蛋白的易位， 以及GLUT 1 mRNA稳定化。 GLUT 1 mRNA稳定结果 在没有增加的情况下，GLUT 1 mRNA的主要积累 转录。 GLUT 1 mRNA含量的增加促进了合成， 导致观察到的进入细胞的葡萄糖的主要增加。 我们建议检查TNF诱导的GLUT 1 mRNA的稳定性的机制。 我们的研究集中在广泛的3 '-非翻译区（UTR）的基因， GLUT 1 mRNA含有一系列序列基序，可能在细胞内发挥作用。 决定稳定性的作用。 我们的初步数据表明， TNF诱导结合至肿瘤坏死因子3' UTR区的蛋白质的活性。 GLUT 1 mRNA的表达，这可能会影响信息的稳定性。 我们 建议纯化和表征3 'UTR结合蛋白; 确定其对mRNA结合和贡献的要求 在无细胞测定系统中的稳定性。 在完整的细胞中，使用 针对纯化的蛋白质制备的抗体，我们将表征 合成，周转和激活的蛋白质响应TNF。 所述研究将在3 T3-L1前脂肪细胞/ 成纤维细胞，并彻底表征GLUT 1 mRNA的调节 稳定 当这些细胞在培养物中分化成脂肪细胞时， 表达第二种转运蛋白GLUT 4（胰岛素反应性葡萄糖 运输商），我们将检查对稳定性的差异影响， 两个传送器 我们的研究解决了TNF干扰 与细胞营养和葡萄糖稳态在许多疾病 处于葡萄糖进入细胞的临界水平。

We have been investigating the role of tumor necrosis factor-alpha (TNF) on the induction and regulation of the catabolic state in 3T3-Ll fibroblasts. Our interest has been focused on the regulation of cellular nutrition at the critical step of glucose entry into the cell. Our data supports the hypothesis that TNF, reminiscent of serum derived growth factors, elevates glucose transport activity as well as transporter (GLUT1) mRNA in 3T3-L1 cells by combined effects on intrinsic GLUT activity, translocation of preexisting transporters as well as GLUT1 mRNA stabilization. The GLUT1 mRNA stabilization results in a major accumulation of GLUT1 mRNA in the absence of increased transcription. The increased content of GLUT1 mRNA fuels synthesis and results in the observed major increase in glucose entry into the cell. We propose to examine mechanisms of TNF-induced stability of GLUT1 mRNA. Our studies focus on the extensive 3'-untranslated region (UTR) of the GLUT1 mRNA which contains a series of sequence motifs that may play a role in determining stability. Our preliminary data demonstrates that TNF induces the activity of a protein that binds to the 3' UTR region of the GLUT1 mRNA, which may effect the stability of the message. We propose to purify and characterize the 3'UTR binding protein(s); determine its requirements for binding and contribution to mRNA stability in a cell-free assay system. In the intact cells, using antibody prepared against the purified protein, we will characterize the synthesis, turnover and activation of the protein in response to TNF. The described studies will be performed in the 3T3-L1 preadipocytes/ fibroblasts and thoroughly characterize the regulation of GLUT1 mRNA stability. As these cells differentiate in culture to adipocytes and express a second transporter, GLUT4 (insulin responsive glucose transporter) we will examine for differential effect on the stability of both transporters. Our studies address the ability of TNF to interfere with cellular nutrition and glucose homeostasis in numerous disease states at the critical level of glucose entry into the cell.