非编码RNA参与2型猪链球菌89K毒力岛致病作用的分子机制研究

项目名称： 非编码RNA参与2型猪链球菌89K毒力岛致病作用的分子机制研究

项目编号： No.81471920

项目类型： 面上项目

立项/批准年度： 2015

项目学科： 医药、卫生

项目作者： 王长军

作者单位： 中国人民解放军东部战区疾病预防控制中心

项目金额： 72万元

中文摘要： 2型猪链球菌（SS2）是一种危害严重的人畜共患病原菌，江苏和四川曾暴发较大规模的猪群及从业人群感染，流行株高致病的机制尚未阐明。非编码小RNA(sRNA)是一类新型调控分子，与细菌环境适应、毒力调控等密切相关。课题组前期发现国内SS2强毒株携带特有的89K毒力岛（PLOS ONE，2007），对4株SS2全基因序列综合预测，在89K岛核心功能区发现2个候选sRNA（SR36、SR37），可能参与该岛致病性等功能的调控。本研究拟荧光定量PCR分析候选sRNA及其潜在靶基因转录水平与环境压力的关联，构建候选RNA及转录显著关联靶基因的缺失株和互补株，系统比较突变株与野生株在溶血黏附等生物特性、与宿主免疫杀伤细胞相互作用、模型动物致病性等方面的差异；RNA-seq系统分析突变株与野生株转录谱的差异，探索sRNA 在SS2环境适应中的作用，初步解析sRNA参与89K岛致病作用的分子调控机理。

中文关键词： 2型猪链球菌；非编码小RNA；毒力岛；致病机制

英文摘要： Streptococcus suis 2 (S. suis 2, SS2) has evolved into a highly infectious entity, which is responsible for a wide range of serious diseases in both piglets and humans, including meningitis, septicemia, arthritis, etc. Two recent large-scale outbreaks of SS2 infections in China (one in Jiangsu Province, 1998, and the other in Sichuan Province, 2005) were characterized by streptococcal toxic shock syndrome (STSS), and raised significant international concern among the public health professionals. However, the molecular pathogenesis of SS2-caused disease is still poorly understood. The smallnoncoding RNA（sRNA）acting by base-pairing with target mRNAs, resulting in post-transcriptionally regulating gene expression, is the important regulator in the bacterial response to stress, virulence and metabolism.To shed light on the mystery of high virulence of the epidemic outbreak strains of SS2, our joint research group completed a comprehensive study of comparative genomics, decoding the whole genome sequences oftwo virulent SS2 strains(98HAH12 and 05ZYH33) isolated from Chinese infected patients（Plos One，2007）. We analyzed the genome sequences of four classic SS2 strains (98HAH12,05ZYH33,S735,P1/7)and identified a series of sRNA genes and validated the expression of most of them. Screening by RT-PCR analysis revealed that four out of the five sRNA candidates specific to the Chinese endemic strains were transcribed, from which two candidates (SR36 and SR37) are located in IGRs of PAI89K. We thus investigated the possible role and molecular mechanism of the PAI89K specific sRNAs in virulence control and environment adaptation. we'd like to carry out a comprehensive study on contribution of sRNAs to the biological function of PAI89K island， and to elucidatethe molecular mechanism of sRNAs in regulation to environment adaptation and pathogenicity of highly pathogenic SS2 strain,through a series of experimental analhyses by using gene knockout tcchnique, high-throughput sequencing of the transcriptome(RNA-seq)， electron microscopy studies,molecular and cellucular assay,and animal infection experiments. Our study will facilitate further understanding of SS2 pathogenesis and points to directions of development on some effective strategies to combat highly pathogenic SS2 infections in China.

英文关键词： streptococcus suis serotype 2;small noncoding RNA;pathogenicity island;pathologic mechanism