miRNA调控细胞自噬及其在PRRSV增殖中作用与机制研究

Porcine reproductive and respiratory syndrome (PRRS) is a viral disease with huge economic losses that is difficult to control in the word, and there are no effective medicines and techniques for prevention and treatment at present. The literatures reported that miRNA is an important regulator in cell autophagy and virus proliferation, and also the new effective target molecule for medicine design. In our previous studies, we identified some differently expressed-miRNA and cell autophagy were triggered by PRRSV infection. In addition, we also found that these miRNA and cell autophagy not only regulated the PRRSV proliferation, but also there were interaction between them. However, the regulatory effect and mechanism of these miRNA on the cell autophagy and PRRSV proliferation are not clear..In this study, the regulatory effect of these above miRNA on cell autophagy and PRRSV proliferation will be investigated, and the regulatory effect of miRNA on signaling pathways of cell autophagy and the important genes on the pathways, and the regulation network and mechanism of PRRSV proliferation will also be explored. The aims of this study are to explain the regulatory effect and mechanism of miRNA on cell autophagy infected by PPRSV, and of cell autophagy on PRRSV proliferation, and also to discover the key genes, miRNA and their target genes that effectively regulate the cell autophagy and PRRSV proliferation. The results from this project will contribute to understand the host and PRRSV interaction and the mechanism of host resistance, and to provide theoretical basis for target molecule of new medicine of prevention and breeding the disease-resistant breed.

猪繁殖与呼吸系统综合症（PRRS）是危害大控制难的世界性传染病，目前尚无有效的防治药物和技术。研究表明miRNA不仅对细胞自噬及病毒增殖等具有重要作用，还是药物设计的有效新型靶分子。我们前期研究发现PRRS病毒能导致miRNA差异表达和细胞自噬，miRNA和自噬均参与调控PRRSV增殖、且两者间存在互作；然而miRNA调控自噬及其在PRRSV增殖中作用与机制尚不清楚。本项目将研究miRNA对自噬和PRRSV增殖调控效应，探讨miRNA对自噬相关信号通路和重要基因的作用及其对PRRSV增殖的调控网络与机理，旨在：①阐明自噬在PRRSV增殖中作用及其机理；②解析miRNA对感染PRRSV后细胞自噬的调控作用与机理；③挖掘参与调控自噬及PRRSV增殖的关键基因、miRNA及其靶基因，为阐明宿主与PRRSV互作、宿主抗病机制奠定基础，为防治PRRS新药设计的靶分子和抗病新品种的培育提供理论依据。

1、主要研究内容包括：. （1）猪繁殖与呼吸系统综合症病毒（PRRSV）感染中miRNA表达、自噬及PRRSV增殖的动态变化规律的研究；（2）miRNA对自噬及PRRSV增殖调控的方式与效应的分析；（3）miRNA对PRRSV诱导自噬的调控作用与机理的探讨；（4）自噬在PRRSV增殖中作用与机理的研究。..2、重要研究成果包括：.（1）PRRSV感染中miRNA及其靶基因对病毒增殖的作用与机理：获得了二个重要miRNA（miR-145、miR-15），以及miR-15的二个靶基因（MAP2K1、Bcl2l2）、miR-145的三个靶基因（IFNGR1、Beclin1、TRAM1）；并阐明了miR-145及其靶基因对病毒复制增殖的机理。.（2）PRRSV诱导的自噬及其在病毒增殖中的作用与机理：（A）PRRSV感染早期，PRRSV诱导自噬和抑制凋亡；（B）PRRSV诱导自噬和利用自噬来促进病毒增殖；（C）自噬通过抑制凋亡来促进PRRSV增殖。 .（3）自噬蛋白与凋亡蛋白互作在PRRS增殖中的调控机理：（A）PRRSV感染使Bcl2家族蛋白中BH3-Only蛋白Bad的氨基酸Ser112磷酸化、改变Bad的亚细胞定位、Bad与Bcl2家族蛋白及Beclin1的共定位或互作；（B）Bad调控PRRSV诱导的凋亡，也参与病毒诱导的自噬；（C）Bad通过调控PRRSV诱导的自噬和凋亡来调节PRRSV增殖。.（4）线粒体自噬在PRRSV增殖中的作用及机理：PRRSV诱导线粒体自噬（自噬中的一种），PRRSV利用自噬来促进病毒增殖，PRRSV诱导的线粒体自噬主要通过抑制凋亡过程从而促进了病毒增殖。.（5）线粒体动态信号通路在PRRSV增殖中的作用及机理：PRRSV诱导线粒体分裂相关因子Drp1的 Ser616位点磷酸化、激活Drp1依赖的线粒体动态信号通路促进 Drp1依赖的线粒体分裂，线粒体分裂通过抑制凋亡来促进病毒在细胞中增殖。.（6）培养了2名博士和4名硕士研究生。发表了10篇文章，其中8篇SCI收录，2篇中文文章。. .3、研究结果的重要意义：从miRNA、自噬、线粒体自噬等角度阐明了RRSV增殖的调控作用及其机理，为研究PRRS感染机理、病毒与宿主互作机理，以及为抗病毒的药物和疫苗设计提供新的靶分子、为基因编辑修饰策略培育抗病品种提供候选基因。