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

项目摘要 弓形虫是一种专性细胞内寄生虫，可引起免疫功能低下的严重疾病。 个体（例如，艾滋病患者）和胎儿。它能够在所有有核细胞内增殖， 几乎所有的温血动物都感染了这种寄生虫，这使得它成为研究其机制的理想模型 参与宿主-病原体相互作用。弓形虫感染的结果因宿主物种而异。为 例如，小鼠通常死于急性弓形虫感染，而大多数非鼠宿主，如大鼠， 和人类，通常不显示症状，但慢性感染是建立的。作为一种细胞类型 巨噬细胞决定感染的结果，在早期先天性免疫应答中起重要作用 对抗弓形虫并协调适应性免疫应答。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物来吸收宿主巨噬细胞 (e.g.,棒状体和致密颗粒），分别称为ROP和GRA。弓形虫效应子的作用 主要在小鼠巨噬细胞中进行了研究，然而，在大鼠中导致感染的效应物 和人类巨噬细胞的情况还不清楚。我以前的研究，加上初步的数据， 项目，确定了几个弓形虫效应，特别是调节先天性免疫反应的大鼠 而不是鼠巨噬细胞。我的中心假设是弓形虫分泌一种不同的寄生虫 参与调节各种先天性免疫应答以建立感染的效应物， 来自非鼠宿主的巨噬细胞。K99辅导阶段的目标是：1）了解 大鼠巨噬细胞中弓形虫效应子介导的NLRP 1炎性体活化的机制; 2） 机制上确定弓形虫效应子的作用，需要寄生虫增殖在幼稚 大鼠巨噬细胞在独立R 00阶段，我将应用指导阶段的培训来学习 弓形虫效应子与人巨噬细胞先天免疫应答之间的相互作用。 具体来说，我将鉴定赋予适合度的弓形虫分泌效应物， 在人类巨噬细胞中的效应调节宿主转录反应。为了实现这些目标， 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 独立研究员。此外，我将发展我的领导能力和加强我的技术技能 通过拟议的培训。总的来说，这个项目的完成将加强我们对 控制宿主对弓形虫感染易感性的分子机制。而且，了解了寄生虫 对宿主调节重要的效应物将提供更好的抗弓形虫病的药物靶点。

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.