Placental resistance and response to the teratogenic pathogen Toxoplasma gondii

项目总结/摘要： 如果在妊娠期感染弓形虫， 怀孕大量的先天性T。每年发生弓形虫感染（在美国约4000例及以上 200，000），使T.弓形虫是最重要的致畸病原体之一。到目前为止， 预测T. gondii-naïve孕妇最终会传染给胎儿。先天性 弓形虫病仅发生在T.弓形虫突破胎盘屏障，但对细胞的了解很少。 以及在宿主-病原体相互作用过程中发生的分子事件，以及这些事件如何影响感染 结果。在这份提案中，我们概述了一系列旨在了解 当弓形虫遇到胎盘细胞时会发生，以及这可能如何影响感染 发育中的胎儿的结果。我们工作的一个主要重点是胎盘滋养层细胞， 发育中的胎儿和母体血液之间的界面。我们广泛的初步和公布的数据坚定地 胎盘合体滋养层细胞（SYNs）抗弓形虫作用研究 感染，而滋养层弓形虫感染诱导独特的转录应答 与迄今为止研究的大多数细胞类型相比。在目标1中，我们利用了SYN的多种遗传学上易于处理的模型 功能和发展，以确定SYN抗性机制，并在分子水平上验证它们。 这一目标的重要性源于这样一个事实，即SYNs是迄今为止唯一研究的细胞类型 对T有抵抗力弓形虫感染在目标2中，我们讨论了先天免疫信号的重要性。 在先天性传播的母胎界面上。在Subaim 2.2.我们将通过量化 在一组独特的人血清样品中检测多种免疫调节细胞因子， 妊娠期间的妊娠血清转换事件，然后使用多变量分析将免疫 不同感染结果的信号特征。在Subaim 2.2.我们将从基因上消除多重宿主定位 效应子T.弓形虫（包括一种改变胎盘细胞中特异性免疫调节的基因）， 并将先天性传播动态与成熟小鼠的免疫调节状况联系起来 先天性传播的模式。拟议研究的影响来自（1）使用初级胎盘 细胞色素T和细胞色素N的组织和易处理的细胞系模型，以解码抗性的关键分子机制 （2）T.弓形虫感染， 在先天性暴露事件期间宿主反应的变化，以及（3）协同和公认的 co-PI团队（Coyne和波义耳）的合作，利用他们在分子生物学方面的专业知识， 弓形虫宿主-病原体相互作用（波义耳）与胎盘发育的细胞和分子基础 和病原体抗性（Coyne）。

PROJECT SUMMARY/ABSTRACT: Toxoplasma gondii can have devastating consequences in the developing fetus if it is acquired during pregnancy. A significant number of congenital T. gondii infections occur yearly (~4000 in the U.S. and over 200,000 worldwide), making T. gondii among the most important teratogenic pathogens. To date it is not possible to predict whether infection of a T. gondii-naïve pregnant woman will ultimately transmit to the fetus. Congenital toxoplasmosis occurs only after T. gondii breaches the placental barrier, yet very little is known about the cellular and molecular events that occur during this host-pathogen interaction, nor how these events affect infection outcome. In this proposal we outline a series of complementary experiments aimed at understanding what happens when Toxoplasma gondii encounters cells of the placenta and how this might impact infection outcome in the developing fetus. A major focus of our work is on placental trophoblasts which form the primary interface between the developing fetus and maternal blood. Our extensive preliminary and published data firmly establish that placental syncytiotrophoblasts (SYNs) but not cytotrophoblasts (CYTs) resist Toxoplasma infection, and that Toxoplasma infection of trophoblasts induces a transcriptional response that is unique compared to most cell types studied to date. In Aim 1 we exploit multiple genetically tractable models of SYN function and development to identify SYN resistance mechanisms and validate them at the molecular level. Significance of this aim derives from the fact that SYNs are unique in being the only cell type studied to date that is intrinsically resistant to T. gondii infection. In Aim 2 we address the importance of innate immune signaling at the maternofetal interface during congenital transmission. In Subaim 2.2. we will do this by quantifying multiple immunomodulatory cytokines in a unique set of human serum samples that longitudinally cover gestational seroconversion events during pregnancy, and then use multivariate analyses to link immune signaling profiles to different infection outcomes. In Subaim 2.2. we will genetically ablate multiple host-targeting effectors in T. gondii (including one that alters the immunoregulatory landscape specifically in placental cells), and link congenital transmission dynamics to the immunomodulatory landscape in a well-established mouse model of congenital transmission. Impact of the proposed studies derives from (1) the use of primary placental tissues and tractable cell line models of CYTs and SYNs to decode critical molecular mechanisms of resistance and susceptibility, (2) the use of serum samples before, during and after T. gondii infection to robustly quantify changes in the host response during congenital exposure events and (3) the synergistic and well-established collaboration of the co-PI team (Coyne and Boyle) which leverages their expertise in the molecular biology of Toxoplasma host-pathogen interactions (Boyle) and the cellular and molecular basis of placental development and pathogen resistance (Coyne).