Function of metal transporter ZIP14 as regulated by proinflammatory stimuli

描述（由申请人提供）：锌是一种必需的微量营养素，是维持健康所必需的。潜在的机制尚不清楚，但有证据表明锌在控制信号通路中起作用，例如蛋白激酶，蛋白磷酸酶和转录因子磷酸化。它的作用类似于细胞内离子浓度控制功能的钙。细胞使用来自两个基因家族的24种不同的锌转运蛋白将锌离子引导到细胞内的位置。一些锌转运基因响应膳食锌的供应并参与体内平衡，而其他一些则受细胞因子和激素的调节。我们已经确定了两个锌转运基因Zip8和Zip14，它们响应促炎细胞因子。活化T细胞的溶酶体通过ZIP8介导的Zn2+转运将CREB维持在其磷酸化区，从而增强IFNy的转录。我们已经证明Zip14在il - 6、il - 12和一氧化氮的刺激下在肝细胞中被诱导。ZIP14刺激Zn2+转运，并具有功能结果，如与金属响应转录因子MTF1相互作用。本课题的重点是利用ZIP14基因敲除小鼠来探讨ZIP14的生理作用。我们对这个项目的假设是Zip14在促炎条件下上调，并在肝脏、胃肠道和肌肉中运输锌的功能。我们将通过三个相互关联的具体目标来检验我们的假设：描述Zip14-/-小鼠的表型，包括Zip14缺失对体内和原代细胞中金属运输的影响。2. 评估ZIP14在小鼠肝脏再生和炎症反应中的作用。3. 炎症过程中肝脏、胃肠道和肌肉信号通路中Zip14缺失和表达的生理后果。这些实验的基本原理是ZIP14 （SLC39A14）转运体对促炎刺激有反应，因此在许多病理生理条件下失调，产生改变的锌信号。这些可能受益于锌补充剂或旨在影响ZIP14活性的药物。

DESCRIPTION (provided by applicant): Zinc is an essential micronutrient that is required to maintain health. The underlying mechanisms are unknown, but evidence is emerging that zinc has roles in control of signaling pathways, e.g. protein kinases, protein phosphatases and transcription factor phosphorylation. The role is similar to that of calcium where the intracellular ion concentration controls functions. Cells use 24 different zinc transporter proteins derived from two gene families to direct zinc ions to intracellular sites. Some zinc transporter genes respond to the dietary zinc supply and participate in homeostasis, whereas a few others are regulated by cytokines and hormones. We have identified two zinc transporter genes Zip8 and Zip14, which respond to proinflammatory cytokines. ZIP8 mediated transport of Zn2+ from lysosomes of activated T cells maintains CREB in its phosphorylated forum enabling enhanced IFNy transcription. We have demonstrated that Zip14 is induced in hepatocytes upon stimulation by IL6, IL12 and nitric oxide. ZIP14 stimulates Zn2+ transport and has functional outcomes such as interaction with the metal responsive transcription factor, MTF1. The focus of this proposal is to explore the physiologic role of ZIP14 using Zip14 knockout mice. Our hypothesis for this project is that Zip14 is up-regulated by pro-inflammatory conditions and transports zinc for functions in liver, the gastrointestinal tract, and muscle. We will test our hypothesis through three interconnected specific aims: 1. Characterize the phenotype of the Zip14-/- mouse including the effects of Zip14 deletion on metal transport in vivo and in primary cells. 2. Evaluate the involvement of ZIP14 in murine liver regeneration and during inflammatory responses. 3. Physiologic consequences of Zip14 Deletion and Expression in signaling pathways in liver, gastrointestinal tract and muscle during inflammation. The rationale for these experiments is that the ZIP14 (SLC39A14) transporter is responsive to proinflammatory stimuli and hence is dysregulated in many pathophysiologic conditions producing altered zinc signaling. These may benefit from zinc supplementation or drugs designed to influence ZIP14 activity. PUBLIC HEALTH RELEVANCE: There is strong evidence for the biochemical roles of zinc, however, we do not have a clear understanding of how these functions maintain health. Research from this project is relevant to NIH's mission as it addresses how humans acquire and utilize zinc in an integrative manner, via regulated expression of zinc transporters, to effectively maximize functions of this micronutrient in the promotion of health. This project will examine the expression and function of a zinc transporter (ZIP14) that is dramatically up-regulated by pro-inflammatory conditions using a gene knockout model. We will examine how ZIP14 expression in the gastrointestinal tract, liver and muscle influences metal ion transport and specific cell signaling pathways. Since ZIP14 is increased during inflammation zinc supplementation or drugs targeting ZIP14 activity may influence related to inflammation.