microRNA-27a和microRNA-92a在EIAV强弱毒诱导宿主差异炎症反应中的作用机制研究

Equine infectious anemia virus (EIAV) and HIV-1 are both members of the Lentiviruses Genus and are similar in major virologycal characters. The live attenuated EIAV vaccine developed by Chinese scientists in the 1970s is the first lentiviral vaccine that was approved safe and effective after being applied country-widely. The decoding of the functional mechanism of the live attenuated EIAV vaccine should provide a valuable reference for the development of other lentiviral vaccines. The horses infected by EIAV virulent strain showed severe inflammation, but the horses infected by EIAV attenuated strain did not show excessive inflammatory response and can acquire effective immune protection. As a key regulatory molecule, microRNA plays an important role in the regulation process of inflammation. Our preliminary studies revealed that the expression of microRNA-27a (miR-27a) and microRNA-92a (miR-92a) was significantly increased in the target cell infected by EIAV vaccine strain compared with the cells infected by the virulent strain.The literature report and our study confirmed that these two microRNA have the function of inhibiting inflammation. Maybe these two microRNAs have important links with the mechanism on balancing the inflammation and immune protection of the horses infected by EIAV attenuated vaccine. This proposal intends to analyze the molecular mechanism of miR-27a and miR-92a differential expression in target cells by EIAV attenuated and virulent strains infection, and to explore how these two microRNAs inhibit the inflammation. After integrated analysis, we can deeply interprete the mechanism of EIAV attenuated vaccine from a new perspective.

同属慢病毒的马传染性贫血病毒（EIAV）与艾滋病毒相似。我国研制的EIAV弱毒疫苗，是首例经应用证实安全、有效的慢病毒疫苗。阐明该疫苗的作用机理，将为其他慢病毒疫苗的研究提供借鉴。EIAV强毒株感染马的主要症状体现为重度炎症，而弱毒疫苗免疫马则没有过度的炎症反应，并获得了有效保护。microRNA(miR)作为一种重要的调控小分子，在炎症反应的发生过程中发挥了重要的调节作用。前期研究表明，EIAV疫苗株感染靶细胞，可显著上调miR-27a和miR-92a的表达，已证实这两个microRNA具有抑制炎症的功能，提示这与弱毒疫苗可有效平衡炎症而发挥免疫保护作用有关。因此，本项目拟深入分析EIAV强弱毒感染造成靶细胞miR-27a和miR-92a差异表达的分子机制，以及这两个microRNA抑制炎症反应的具体作用模式。综合分析后，本项目将从一个全新的角度去解读EIAV弱毒疫苗的作用机理。

同属慢病毒的马传染性贫血病毒（EIAV）与艾滋病毒相似。我国研制的EIAV 弱毒疫苗，是首例经大规模应用证实安全、有效的慢病毒疫苗。阐明该疫苗的作用机理，将为其他慢病毒疫苗的研究提供借鉴。EIAV强毒株感染马的主要症状体现为重度炎症，而弱毒疫苗株感染马则没有过度的炎症反应，并获得了有效的免疫保护。microRNA作为一种重要的调控小分子，在炎症反应的发生过程中发挥了重要的调节作用。本研究通过高通量测序比较了EIAV强弱毒感染马巨噬细胞后microRNA表达谱的差异，发现炎症调控相关的miR-92a在强毒感染细胞中下调表达，在弱毒感染细胞中上调表达。该分子可促进EIAV病毒的复制，但并不直接靶向病毒基因组本身，进一步分析发现miR-92a可抑制促炎因子TNF-α、IL-β和干扰素IFN-β的表达。通过对miR-92a宿主靶基因的筛选，发现与炎症调控相关的靶基因为CD69，该靶基因可抑制病毒的复制。综上所述，本研究发现了EIAV强弱毒导致不同炎症反应的关键调控microRNA-miR-92a及其调控的分子机制，为EIAV弱毒疫苗作用机理的解读奠定了基础。