Exosomes/miR-7/Bcl-2途径参与电离辐射远位效应的研究

An abscopal effect induced by ionizing radiation has brought new challenges to the traditional concept of radiation protection. It is essential to explore the unclear mechanisms of abscopal effects to meet this challenge. Our preliminary experiments found that mice lung showed significant autophagy 2 and 6 hours post brain’s 10Gy ionizing radiation (IR) and miR-7 was remarkably up-regulated in exosomes from Hela’s media 8 hours post 2Gy’s IR detected by miRNA array. Further, exosomes containing miR-7 was detected to excrete from mice brain and go into blood. According to the results, a scientific hypothesis is proposed: the exosomes with miR-7 in blood fused the lung cells and induced autophagy or even apoptosis targeting Bcl-2 gene. So, in this project, GFP-LC3 mice and the methods such as luciferase activity test, qRT-PCR, western blot and immunohistochemistry will be used to test our hypothesis. The coming exosomes/ miR-7 /Bcl-2 signal pathway results will partly clarify the mechanism of abscopal effects and provide theoretical basis of biological protection for non-target effects.

电离辐射远位效应对传统的辐射防护带来了新的挑战，应对这一挑战，对其机制的探索显得至关重要。我们前期工作发现：1，小鼠脑部10Gy照射后2小时和6小时肺部发生了自噬；2，Hela细胞2Gy照射后8小时培养基外泌体（exosomes）中miRNA表达谱芯片结果显示miR-7显著高表达。进一步实验表明：当小鼠脑部受照时，可引起脑部分泌含有miR-7的外泌体并进入血液。对此本文提出科学假设：血液中的外泌体到达肺部后，miR-7进入靶细胞，下调靶基因Bcl-2引起肺部的自噬甚至凋亡。因此，本项目拟采用GFP-LC3等小鼠，用双荧光素酶活性实验、qRT-PCR、Western Blot、免疫组化等方法进行脑到肺部信号传递过程中exosomes/miR-7/Bcl-2途径的研究，率先阐明此信号途径调节电离辐射远位效应的机制和规律，为非靶效应的生物防护奠定理论基础，为辐射防护增加新的视角和策略。

电离辐射远位效应对传统的辐射防护带来了新的挑战，应对这一挑战，对其机制的探索显得至关重要。因此，本项目采用细胞和GFP-LC3等小鼠，用双荧光素酶活性实验、qRT-PCR、Western Blot、免疫组化等方法进行脑到肺部信号传递过程中exosomes/miR-7/Bcl-2途径的研究；以及联合应用转录组学和蛋白组学技术，阐明电离辐射早期和远期远位效应的机制和规律。本研究结果发现，Bcl-2是miR-7的直接靶基因，Exosome/miR-7通过调节Bcl-2介导了脑部受照后早期肺部细胞的自噬。小鼠脑部照射后可引起远期肺纤维化，其中LC3参与小鼠脑部照射后肺纤维化的发生和调节，其机制为LC3通过调节TGF-β通路，增加periostin的表达，诱导肺纤维化的发生。除此之外，小鼠脑部照射后，miR-21a-5p下调，经血液循环至肺部调节靶基因Tgfbi，引起肺部纤维化相关蛋白TGF-β1、periostin、fibronectin的表达增加，进而引起肺纤维化。研究结果为非靶效应的生物防护丰富了理论基础，为远位效应的辐射防护增加新的视角和策略。