我国弓形虫优势基因型效应分子ROP16/GRA15多态性及其致不良妊娠结局的机制研究

项目名称： 我国弓形虫优势基因型效应分子ROP16/GRA15多态性及其致不良妊娠结局的机制研究

项目编号： No.81471983

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： 沈继龙

作者单位： 安徽医科大学

项目金额： 72万元

中文摘要： 弓形虫寄生在有核细胞内，其垂直传播严重危害人类健康和畜牧业生产。近年发现，部分抗体阳性孕妇甚至实验感染动物流产的病理组织中难以查见虫体和DNA，推测免疫机制是妊娠失败的主要原因。弓形虫毒力分子具有基因型相关的多态性：I/III和II型虫株ROP16和GRA15的多态性分别驱动巨噬细胞向M2和M1极化，诱导宿主迥异的免疫应答。我国的弓形虫优势基因型虫株Wh3兼具I/III型ROP16和II型GRA15的多态性，其诱导母-胎界面的免疫失衡致流产可能具有独特的致病机制。本课题采用ROP16I/III和GRA15II重组病毒转染巨噬细胞，诱导的M2和M1分别与滋养细胞和Th17共培养、体内转输、ROP16基因敲除虫株感染等，揭示上述两个效应分子诱导的滋养细胞凋亡和Wh3虫株致流产的机制，为基因型相关的致病机制和我国流行的优势基因型弓形虫病的防治研究具有重要的理论与实际意义。此项研究国内外未见报告。

中文关键词： 弓形虫；基因型；多态性；流产；致病机制

英文摘要： Toxoplasma gondii is an intracellular protozoon. The vertical transmission of T.gondii causes abortion, constituting a serious threat to humans and leading to great losses of livestock production. It has been reported that no parasites，and their DNAs as well, are detectable in some diseased samples with abnormal pregnancy outcomes, suggesting that an immunity-related pathogenesis induced by T. gondii might be involved. Toxoplasma virulence effectors possess the genotype-associated polymorphism. ROP16 and GRA15 carried by type I,III and II strains drive macrophages to M2 or M1, respectively,inducing a remarkably different immune consequences. It is hypothesized that strains with genotype Chinese 1(Wh3) prevalent in China may have the pathogenesis differing from the strains with archetypical types due to the fact that Wh3 is characterized by sharing ROP16I/III and GRA15II polymorphisms. Both effectors polymorphisms noted in type Chinese 1 strains may induce imbalance at maternal-fetal interface and account for the failure of pregnancy caused by Toxoplasma infection in some cases. The present study will uncover the pathway of trophoblast apoptosis induced by transfected macrophages and illuminate the mechanism by which Wh3 strain induces mouse abortion,by using mouse bone marrow macrophages(mBMMφ)transfection with recombinant ROP16I/III and GRA15II viruses, transwell culture of polarized macrophages with trophoblasts and Th17 cells, in vivo cells inoculation, and rop16I/III-knock out parasite infection of pregnant ICR mice. So far, no relevant approach has been available. The results will provide a deep insight into the pathogenesis of abnormal pregnancy caused by Toxoplasma genotype predominantly circulating in China.

英文关键词： Toxoplasma;genotype;polymorphism;abortion;pathogenesis