单核细胞增生性李斯特菌（LM）是最致命人兽共患食源性致病菌之一。LM可以穿越血脑屏障，导致人和动物中枢神经系统感染，但LM穿越血脑屏障的机制仍知之甚少。最近，LM泛基因组学和动物试验表明LM毒力岛4（LIPI-4）与神经系统感染密切相关。本项目拟构建LIPI-4基因缺失株，以脑微血管内皮细胞（BMEC）为血脑屏障模型，进行LM在BMEC中增殖的比较转录组学研究，筛选由LIPI-4调控的LM差异表达基因；并用Q-PCR检测差异基因在LM侵染不同类型细胞和感染小鼠不同器官中的表达水平，进一步筛选在BMEC和脑组织中特异性表达的差异基因；同时对编码未知功能蛋白的差异表达基因，进行缺失株和互补株的构建，通过胞内增殖、胞间传播，小鼠致病性等试验，评价编码未知功能蛋白的基因在LM致病性上的作用。研究将阐明LIPI-4在LM侵袭中枢神经的分子机制，为LM致病机制和药物靶点研究提供理论基础。

Listeria monocytogenes (LM) is one of the most deadly zoonotic foodborne pathogenic bacteria. LM can cause human and animal central nervous system（CNS）infection by cross the blood brain barrier(BBB), but the mechanism enabling LM to cross the BBB remains poorly understood. Recently, pan-genomic analysis of LM and animal experiments showed that LIPI-4 gene cluster was closely related to CNS infection.In this research, LIPI-4 gene deletion mutants will be constructed, brain microvascular endothelial cells (BMEC) will be used as a model of BBB.A LM comparative transcriptome study of proliferation in BMEC will be performed, and LM differentially expressed genes regulated by LIPI-4 will be screened. Q-PCR will be used to detect the differential genes above screened in different types of cells and in different organs of mice infected by LM, and further to screen LM differentially expressed genes in BMEC and brain tissue. On the other hand, the deletion and complementary strains of the differential expression genes encoding unknown function proteins will be constructed. The genes encoding unknown function proteins will be evaluated by means of intracellular proliferation, intercellular transmission and mouse pathogenicity test.This study will elucidate the molecular mechanism of LIPI-4 in the CNS infection of LM and provide a theoretical basis for the study of LM pathogenesis and drug targets.