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

项目概要 弓形虫是一种专性细胞内寄生虫，可在免疫功能低下者中引起严重疾病 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 几乎所有温血动物都受到感染，使寄生虫成为研究其机制的理想模型 参与宿主与病原体的相互作用。弓形虫感染的结果因宿主物种而异。对于 例如，小鼠通常会死于急性弓形虫感染，而大多数非鼠科宿主，例如大鼠 和人类一样，通常不会表现出症状，但会形成慢性感染。作为细胞类型之一 确定感染结果，巨噬细胞在早期先天免疫反应中发挥重要作用 对抗弓形虫并协调适应性免疫反应。为了成功建立感染， 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，菱形和致密颗粒），分别命名为 ROP 和 GRA。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器 而人类巨噬细胞大多是未知的。我之前的研究，以及本次研究的初步数据 项目确定了几种特异性调节大鼠先天免疫反应的弓形虫效应子 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 效应器参与调节各种先天免疫反应以建立感染 来自非鼠宿主的巨噬细胞。 K99 指导阶段的目标是： 1) 了解 弓形虫效应介导的大鼠巨噬细胞NLRP1炎症小体激活机制； 2）到 机械地确定幼稚寄生虫增殖所需的弓形虫效应器的作用 大鼠巨噬细胞。在独立R00阶段，我会运用导师阶段的训练来学习 弓形虫效应器与人类巨噬细胞先天免疫反应之间的相互作用。 具体来说，我将识别赋予适应性的弓形虫分泌效应器，并主要确定寄生虫 人类巨噬细胞中效应器调节的宿主转录反应。为了实现这些目标，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指导我走向成功的道路 独立研究员。此外，我将发展我的领导技能并加强我的技术技能 通过建议的培训。总的来说，该项目的完成将增强我们对 控制宿主对弓形虫感染易感性的分子机制。另外，了解寄生虫 对宿主调节很重要的效应器将提供更好的抗弓形体病药物靶点。

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.