锌通过信号分子MTF-1和KLF4调控鱼肠道GSH合成的作用机制研究

鱼肠道结构和功能的完整性与其抗氧化状态密切相关。GSH是鱼体内最重要的抗氧化物质，在维持抗氧化状态中起着至关重要的作用。锌是鱼类必需的矿物质。本课题前期的研究发现，锌能促进鱼类生长，提高肠道GSH含量，但其作用机制不清楚。GCL是GSH从头合成的关键酶，其活性可能受信号分子Nrf2调控。人上的研究发现Nrf2依赖于细胞内锌离子浓度，其下游信号分子keap1能灵敏感知胞内锌浓度。然而，锌是否通过调控胞内锌浓度，激活Nrf2/ARE从而提高GCL活性还不清楚。胞内锌浓度可能受锌转运蛋白（ZnTs和ZIPs）及其调控信号分子MTF-1和KLF4的影响，但在鱼类上未见研究。因此，本项目结合体内外试验，研究锌是否通过调控胞内锌浓度激活Nrf2/ARE信号通路，从而调控GCL的活性；在此基础上研究锌转运蛋白对胞内锌浓度的调控及其信号通路。该项目将为阐明锌提高鱼类抗氧化能力的作用机制奠定重要基础。

The intestinal structure and function integrity of fish is closely related to its antioxidant status. GSH is the most important antioxidant in fish, and it plays an important role in the maintenance of antioxidant status. Zinc is an essential trace element that plays important role in fish. Recent study in our group found that zinc could promote the growth of fish, improve the intestinal GSH content, but the mechanism remains unknown. GCL is a key enzyme in the de novo synthesis of GSH. The activity of GCL may be regulated by Nrf2. The study on human found that the activity of Nrf2 depends on the concentration of intracellular zinc, and its downstream signal molecule Keap1 can be sensitive to intracellular zinc concentration. However, it is not clear whether zinc activates Nrf2/ARE to increase GCL activity by regulating the intracellular zinc concentration. Intracellular zinc concentrations may be influenced the zinc transporter (ZnTs and ZIPs),which may be regulated by signal molecule MTF-1 and KLF4 respectively, but there is no relative research in fish. Therefore, the current project combined with the research in vivo and in vitro, firstly study whether zinc activates Nrf2/ARE pathway regulated by the intracellular zinc concentration , and then regulate GCL activity and GSH content in fish. Secondly we carry out the study focus on the effects of zinc transporter on intracellular zinc concentration. Thirdly, we investigate the signal pathway which regulate the expression of zinc transporters gene pathway. The project will provide valuable foundation for elucidating the mechanism of the effect of zinc on improve the antioxidant capacity in fish.