抗氧化NRF2-ARE途径介导的微重力条件下核心节律基因表达调控研究

Biological rhythm change and oxidative stress during space flight may affect astronauts’ health and efficiency, which become the vital medical problem in spaceflight. Antioxidant protein NRF2 can indirectly regulate the expression of core clock genes such as clock and bmal1 through nuclear receptor REV-ERBα. Our previous research showed that both core clock proteins CLOCK and BMAL1, and antioxidant protein NRF2, changed under simulated microgravity. We also found that NRF2 knockdown could inhibit the rhythm expression of CLOCK and BMAL1, and NRF2 might play a crucial role in the generation of rhythmic gene expression in serum-induced NIH/3T3 cells. Moreover, in the promoter region of clock as well as bmal1 gene, there is antioxidant response element (ARE) which can be bound with NRF2. These data indicated the gravity factor regulated NRF2 expression and the interaction between NRF2 and clock and bmal1, thus resulted in the change of rhythm of CLOCK and BMAL1. In this project, we will further explore the binding of NRF2 to its target clock genes using a clinostat to simulated microgravity. This study will promote us to understand the regulation of biological rhythm under microgravity, and may be the important proof in cellular and molecular level for the regulation of circadian clocks by redox homeostasis.

航天飞行条件下生物节律改变和氧化应激可影响机体健康和工作效率。抗氧化蛋白NRF2可通过核受体REV-ERBα间接调节核心节律基因clock、bmal1的表达。我们前期发现，模拟失重条件下CLOCK、BMAL1和NRF2表达均发生改变；NRF2敲低可明显抑制CLOCK、BMAL1的节律性，NRF2作为必要因素参与血清诱导成纤维细胞节律性的产生；分析发现，clock、bmal1基因启动子上均存在可被NRF2结合的抗氧化反应元件ARE。这表明，重力因素可影响NRF2的表达，进而影响其与clock、bmal1基因的结合，调节微重力条件下CLOCK、BMAL1的节律性。因此，本项目利用细胞回转器模拟失重效应，研究NRF2与clock、bmal1基因的结合及其在失重性节律基因表达调控中的作用，为微重力条件下生物节律调节机制研究提供基础数据，并可从细胞分子水平阐释生物节律的氧化还原调节机制。

航天飞行条件下生物节律改变和氧化应激可影响机体健康和工作效率。抗氧化蛋白NRF2可.通过核受体REV-ERBα间接调节核心节律基因Clock、Bmal1的表达。我们前期发现，模拟失重条件下CLOCK、BMAL1和NRF2表达均发生改变；NRF2敲低可明显抑制CLOCK、BMAL1的节律性，NRF2作为必要因素参与血清诱导成纤维细胞节律性的产生；分析发现，Clock、Bmal1基因启动子上均存在可被NRF2结合的抗氧化反应元件ARE。这表明，重力因素可影响NRF2的表达，进而影响其与Clock、Bmal1基因的结合，调节微重力条件下CLOCK、BMAL1的节律性。因此，本项目利用细胞回转器模拟失重效应，研究NRF2与Clock、Bmal1基因的结合及其在失重性节律基因表达调控中的作用，主要包括模拟微重力效应对细胞节律基因的表达和节律的影响、NRF2调节Clock和Bmal1表达的分子机制、过表达NRF2可增强模拟微重力效应下节律基因Clock和Bmal1的节律性表达。本项目研究结果表明，模拟微重力效应可导致NRF2蛋白水平降低，ROS水平升高，CLOCK和BMAL1表达降低。Clock基因是NRF2-ARE信号途径的靶基因，模拟微重力效应可通过NRF2-ARE通路直接调节CLOCK的振荡节律。NRF2-ARE通路可能成为在微重力环境下调节昼夜节律的重要靶点。