PI3K/Akt/mTOR通路对HIF-1α的调控在微波辐射后神经元线粒体能量代谢中的作用靶点研究

More and more attention was paid to the biological hazard of microwave exposure, but the injury mechanism was unknown. Our research systematically elucidated that HIF-1α/MAPK pathway played an important role in the mitochrondria injury of hippocampus after microwave exposure in the National Natural Science Foundation of China (No. 30901169). We found that ERK pathway was not the only pathway of regulating HIF-1α expression after microwave exposure, and HIF-1α could repair mitochondria injury induced by microwave. PI3K pathway could regulate HIF-1α expression and activity, and it was not studied in microwave field. The target of HIF-1α on mitochondria metabolism was also unknown. Therefore, based on our research in the past, this study is planned to investigate the effect and mechanism of PI3K pathway and the relation with ERK pathway on regulating HIF-1α activity, and to elucidate target and mechanism of HIF-1α in the process of mitochondia metabolism after microwave exposure, in which pathology, molecular biology, cytobiology and etc are applied. The study will focus on the effect of PI3K pathway on mithchondria injury and HIF-1α activition after microwave exposure; the interaction of ERK pathway and PI3K pathway in HIF-1α activition; the target and mechanism of HIF-1α regulating mitochondia metabolism. This study will establish a foundation on elucidating the molecular mechanism of mitochondria injury induced by microwave and finding prevention and cure targets.

本课题组前期研究(国家自然科学基金青年项目No.30901169)系统地阐明了HIF-1α/MAPK信号通路在微波辐射致海马神经元线粒体损伤中的作用，发现ERK通路并非是调控辐射后HIF-1α表达的唯一途径，且HIF-1α可修复辐射致线粒体能量代谢损伤。鉴于PI3K通路对HIF-1α表达的调控作用以及在微波辐射领域的研究空白，同时HIF-1α对线粒体能量代谢损伤修复的作用靶点未知。本项目拟在前期研究基础上，采用分子生物学和细胞生物学等技术，探讨PI3K/Akt/mTOR通路对HIF-1α的调控在微波辐射后神经元线粒体能量代谢中的作用靶点。重点研究PI3K通路在微波辐射致线粒体损伤和HIF-1α活化中的作用；ERK通路和PI3K通路在HIF-1α激活中的对话；HIF-1α调控线粒体能量代谢损伤修复的作用靶点。为阐明微波辐射脑损伤中的分子机制、研发防治药物提供新思路。

基于HIF-1α在微波辐射致神经元线粒体损伤修复的重要作用，本研究在国家自然科学基金青年项目（30901169）的研究基础上，进一步探讨微波辐射后HIF-1α活化的机制及其对线粒体损伤修复的分子靶点。重点关注：PI3K/Akt/mTOR通路在微波辐射致线粒体损伤和HIF-1α活化中的作用；ERK通路和PI3K/Akt/mTOR通路在HIF-1α激活中的对话；HIF-1α调控线粒体损伤修复的作用靶点。本研究发现：首先，在建立微波辐射致大鼠海马线粒体损伤的动物模型和PC12细胞模型上，发现COX酶活性降低和COX亚基表达异常；同时，发现微波辐射后神经元HIF-1α激活，p-Akt(Ser473)和p-mTOR(Ser2448) 的表达增加激活PI3K/Akt/mTOR通路。其次，干预PI3K/Akt/mTOR通路，发现Akt通路和mTOR通路对HIF-1α均有正调控作用；Akt通路对微波辐射后HIF-1α的调控作用是通过下游的mTOR来实现的；PI3K/Akt/mTOR通路正向影响线粒体功能，表现为正向影响ATP含量和MMP水平。再次，单独或同时干预PI3K/Akt/mTOR通路和ERK通路，发现微波辐射后PI3K/Akt/mTOR通路和ERK通路相互有负向调控作用；微波辐射后PI3K/Akt/mTOR通路和ERK通路分别正调控HIF-1α表达，但二者共同作用相互抵消了对HIF-1α的调控效果。最后，干预HIF-1α的表达后，发现微波辐射后HIF-1α正调控COXIV-1的表达，并促进COXIV-2向COXIV-1转化；微波辐射后PC12细胞HIF-1α正向影响ATP含量和MMP水平，负向影响ROS含量，即HIF-1α活化对线粒体功能具有保护作用；COXIV-1是微波辐射后HIF-1α修复线粒体功能的分子靶点之一。本研究明确了PI3K/Akt/mTOR通路在微波辐射致HIF-1α表达的调控机制；阐明了PI3K/Akt/mTOR通路与ERK通路之间对话；揭示了HIF-1α参与微波辐射后线粒体能量代谢损伤修复的分子靶点。本研究为微波辐射损伤机制的阐明提供创新性实验数据和理论依据，并提供进一步探索微波辐射神经元损伤修复机制的线索和突破口，可为辐射防护提供有效的靶标。本研究获中国体视学会科学技术奖一等奖1项，发表期刊论文2篇，会议论文7篇，参与1项科普宣传片制作。