Placental resistance and response to the teratogenic pathogen Toxoplasma gondii

项目摘要/摘要： 如果弓形虫在发育过程中感染，会对发育中的胎儿造成毁灭性的后果。 怀孕了。每年都有相当数量的先天性弓形虫感染(在美国约有4000人及以上 全球20万人)，使弓形虫成为最重要的致畸病原体之一。到目前为止这是不可能的 以预测弓形虫幼稚孕妇的感染是否最终会传播给胎儿。先天 弓形虫病只有在弓形虫突破胎盘屏障后才会发生，但对细胞内的情况知之甚少。 以及在宿主-病原体相互作用期间发生的分子事件，也不知道这些事件如何影响感染 结果。在这个提案中，我们概述了一系列补充实验，旨在了解 当弓形虫接触胎盘细胞时发生的情况以及这可能如何影响感染 在发育中的胎儿的结局。我们工作的一个主要焦点是胎盘滋养层细胞，它构成了 发育中的胎儿和母体血液之间的接口。我们广泛的初步和公布的数据坚定地 确定胎盘合体滋养层细胞(SYN)而不是细胞滋养层细胞(CYTS)抵抗弓形虫 弓形虫感染滋养层细胞诱导了一种独特的转录反应 与迄今为止研究的大多数细胞类型相比。在目标1中，我们开发了多种SYN的遗传易感性模型 功能和发展，以确定SYN抗性机制，并在分子水平上验证它们。 这一目标的意义源于这样一个事实，即突触细胞是迄今为止唯一被研究的细胞类型 这对弓形虫感染具有内在的抵抗力。在目标2中，我们讨论了先天免疫信号的重要性。 在先天传播过程中母胎交界处。在苏巴伊姆2.2。我们将通过量化来实现这一点 一组独特的纵向覆盖的人血清样本中的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联系起来 不同感染结果的信号特征。在苏巴伊姆2.2。我们将从基因上消除多个宿主靶向 弓形虫中的效应物(包括一种改变免疫调节格局的效应物，特别是胎盘细胞中的一种)， 并将先天性传播动力学与已建立的小鼠免疫调节环境联系起来 先天传播模型。拟议研究的影响来自(1)使用初级胎盘 用于破译抗药性关键分子机制的组织和可处理的细胞系模型 和敏感性，(2)使用弓形虫感染之前、期间和之后的血清样本来强有力地定量 先天性暴露事件中宿主反应的变化以及(3)协同作用和已建立的 联合PI团队(Coyne和Boyle)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-病原体相互作用与胎盘发育的细胞和分子基础 和病原菌抗性(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).