Toxoplasma effector-mediated modulation of innate immune pathways in non-murine macrophages

项目总结 弓形虫是一种专性的细胞内寄生虫，在免疫低下的情况下会导致严重的疾病。 个人(例如，艾滋病患者)和胎儿。它能够在所有有核细胞内增殖并建立一个 几乎所有温血动物的感染都使这种寄生虫成为研究这种机制的理想模型。 参与宿主与病原体的相互作用。不同寄主物种感染弓形虫的结果不同。为 例如，小鼠一般会死于急性弓形虫感染，而大多数非小鼠宿主，如大鼠 而人类，通常不会表现出症状，但慢性感染是确定的。作为一种细胞类型 巨噬细胞在早期的先天免疫反应中起着至关重要的作用，这决定了感染的结局 对抗弓形虫，协调适应性免疫反应。为了成功地确定感染， 弓形虫通过其独特的分泌细胞器分泌的寄生虫效应器来选择宿主巨噬细胞 (例如，棒状和致密颗粒)，分别命名为ROPS和GRAS。弓形虫效应器的作用有 主要在小鼠巨噬细胞中进行研究，然而，导致大鼠感染的效应物 而人类的巨噬细胞大多是未知的。我之前的研究，加上这方面的初步数据 该项目确定了几种弓形虫效应物，它们特异性地调节大鼠的先天免疫反应。 但不是小鼠巨噬细胞。我的中心假设是弓形虫分泌一组不同的寄生虫 效应器参与各种先天免疫反应的调节，以建立感染 来自非小鼠宿主的巨噬细胞。K99指导阶段的目标是：1)了解 弓形虫效应器介导的大鼠巨噬细胞NLRP1炎性小体激活机制 从机制上确定弓形虫在幼虫体内增殖所需的效应因子的作用 大鼠巨噬细胞。在独立的R00阶段，我将应用指导阶段的培训来学习 弓形虫效应物与人巨噬细胞天然免疫反应的相互作用。 具体地说，我将识别与健康相关的弓形虫分泌效应器，并主要确定寄生虫 人巨噬细胞中效应物调节的宿主转录反应。要实现这些目标，有价值的 来自具有科学和指导技能的高度互补的导师团队的培训将引导我走上 独立研究人员。此外，我将发展我的领导能力，并加强我的技术技能 通过拟议的培训。总体而言，这项计划的完成将加深我们对 控制宿主对弓形虫感染易感性的分子机制。此外，了解这种寄生虫 对于宿主调节很重要的效应器将提供更好的药物靶点来对抗弓形虫病。

PROJECT SUMMARY Toxoplasma gondii is an obligate intracellular parasite that causes severe disease in immunocompromised individuals (e.g., AIDS patients) and fetuses. Its abilities to proliferate inside all nucleated cells and establish an infection in almost all warm-blooded animals make the parasite an ideal model to study the mechanisms involving in host-pathogen interaction. The outcome of Toxoplasma infection varies between host species. For example, mice generally succumb to acute Toxoplasma infection while most non-murine hosts, such as rats and humans, usually do not display symptoms but the chronic infection is established. As one of the cell types determining the infection outcome, macrophages play an essential role in the early innate immune response against Toxoplasma and coordinate the adaptive immune response. To successfully establish infection, Toxoplasma co-opts host macrophages via parasite effectors secreted from its unique secretory organelles (e.g., rhoptry and dense granule), named ROPs and GRAs, respectively. The role of Toxoplasma effectors has been predominantly studied in murine macrophages, however, the effectors contributing to the infection in rat and human macrophages are mostly unknown. My previous studies, together with preliminary data of this project, identified several Toxoplasma effectors that specifically modulate the innate immune response in rat but not murine macrophages. My central hypothesis is that Toxoplasma secretes a different set of parasite effectors involved in the modulation of various innate immune responses to establish an infection in macrophages from non-murine hosts. The goals during the K99 mentored phase are: 1) to understand the mechanism of Toxoplasma effector-mediated activation of the NLRP1 inflammasome in rat macrophages; 2) to mechanistically determine the role of Toxoplasma effectors that are required for parasite proliferation in naïve rat macrophages. In the independent R00 phase, I will apply the training from the mentored phase to study the interaction between Toxoplasma effectors and the innate immune response in human macrophages. Specifically, I will identify fitness-conferring Toxoplasma secreted effectors and mainly determine parasite effector-regulated host transcriptional responses in human macrophages. To accomplish these goals, valuable training from a highly complementary mentor team with scientific and mentoring skills will guide my path to an independent researcher. Furthermore, I will develop my leadership skills and strengthen my technical skills through the proposed training. Collectively, the completion of this project will enhance our understanding of the molecular mechanisms controlling host susceptibility to Toxoplasma infection. Also, knowing the parasite effectors important for host modulation will provide better drug targets against toxoplasmosis.