T-bet-regulated myeloid innate defense against Toxoplasma gondii

T-bet 调节的骨髓对弓形虫的先天防御

• 批准号: 10660458
• 负责人: AMERICO HARRY LOPEZ-YGLESIAS
• 金额: $ 31.5万
• 依托单位: INDIANA UNIV-PURDUE UNIV AT INDIANAPOLIS
• 依托单位国家: 美国
• 财政年份: 2023
• 资助国家: 美国
• 起止时间: 2023-07-01 至 2028-06-30
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/10660458
• 关键词: Acute; Adoptive Transfer; Animals; Antiparasitic Agents; B-Lymphocytes; CD4 Positive T Lymphocytes; Cells; Cessation of life; Clinical; Congenital Toxoplasmosis; Cyst; Cytometry; Defense Mechanisms; Development; Fetus; Flow Cytometry; Host Defense; Host resistance; Human; ITGAX gene; Immune; Immune response; Immune system; Immunity; Immunocompromised Host; Immunofluorescence Immunologic; Individual; Infection; Interferon Type II; Interleukin-12; Invaded; Kinetics; Lymphocyte; Lymphoid Cell; Maps; Mediating; Medicine; Molecular; Molecular Biology Techniques; Morbidity - disease rate; Mus; Mutant Strains Mice; Myelogenous; Myeloid Cells; Parasites; Parasitic infection; Population; Production; Regimen; Reporter; Reporting; Research; Role; Sorting; Splenocyte; T cell response; T-Lymphocyte; T-bet protein; Testing; Therapeutic Intervention; Time; Toxic effect; Toxoplasma gondii; Toxoplasmosis; United States; Up-Regulation; acute infection; adaptive immune response; antimicrobial; cell type; conditional knockout; cytokine; experimental study; foodborne; in vivo; mortality; mouse model; myeloid cell development; novel; pathogen; reconstitution; response; side effect; single-cell RNA sequencing; targeted treatment; therapeutic target

Abstract Toxoplasma gondii is the causative agent of toxoplasmosis, and it is estimated to infect a third of the human population globally. T. gondii infection can result in serious complications including congenital toxoplasmosis of the fetus and death among immunocompromised individuals. Unfortunately, current regimens for T. gondii treatment show high rates of toxicity, and are only able to treat the acute stage of the parasitic infection. Therefore, there is an urgent need develop new medicines with specific efficacy against T. gondii. Host immunity against T. gondii is defined by a MyD88-dependent IL-12 response, which generates a CD4+ Th1- derived IFN-γ response necessary for host survival. The transcription factor T-bet is considered essential for the development and function of innate lymphoid cells (ILCs) and TH1s during T. gondii infection. T-bet is traditionally considered the master regulator of lymphocyte-derived interferon-gamma (IFN-γ) production. Yet, T-bet-independent ILC- and TH1-derived IFN-γ is insufficient for host immunity, demonstrating that IFN-γ alone is insufficient for host defense and that T-bet must be inducing an IFN-γ-independent anti-parasitic response. For instance, despite robust IFN-γ production, T-bet-deficient mice succumb to infection significantly faster than animals lacking lymphocytes, suggesting T-bet-expressing myeloid cells are required for host survival. Our objective is to define T-bet’s role in regulating myeloid cell-dependent immunity against T. gondii. Our preliminary findings have identified a unique T-bet expressing CD11c+MHCII- myeloid cell population that are critical for eliminating T. gondii. Based on these results, we hypothesize that T-bet expression in myeloid cells regulates pathogen clearance and host survival during T. gondii infection. To test our hypothesis, we will (i) determine the underlying mechanism(s) of T-bet in regulating myeloid cell-mediated defense against T. gondii (AIM 1) and (ii) define the molecular functions of T-bet-expressing myeloid cells in mediating host resistance against T. gondii (AIM 2). We will utilize unbiased T-bet reporter mice and cell-type-specific T-bet-deficient mice established in our lab, in combination with various molecular biology techniques, spectral cytometry, immunofluorescence, and single-cell RNA-sequencing. Together, these experiments will for the first time establish T-bet’s role in mediating myeloid cell-dependent host defense against T. gondii, thereby providing novel specific targets for therapeutic intervention.

抽象的 弓形虫是弓形虫病的病原体，估计可感染三分之一的人类 全球范围内弓形虫感染可导致严重的并发症，包括先天性弓形虫病。 不幸的是，目前的弓形虫治疗方案会导致免疫功能低下个体的胎儿和死亡。 治疗显示出高毒性，并且只能治疗寄生虫感染的急性期。 因此，迫切需要开发针对弓形虫宿主具有特异性功效的新药物。 针对弓形虫的免疫力是由 MyD88 依赖性 IL-12 反应定义的，该反应会产生 CD4+ Th1- 转录因子 T-bet 被认为是宿主生存所必需的衍生的 IFN-γ 反应。 T. gondii 感染期间先天淋巴细胞 (ILC) 和 TH1 的发育和功能。 传统上被认为是淋巴细胞衍生的干扰素-γ (IFN-γ) 产生的主要调节因子。 不依赖于 T-bet 的 ILC 和 TH1 衍生的 IFN-γ 不足以维持宿主免疫，这表明单独使用 IFN-γ 不足以用于宿主防御，并且 T-bet 必须诱导不依赖于 IFN-γ 的抗寄生虫反应。 例如，尽管 IFN-γ 产生强劲，但 T-bet 缺陷的小鼠死于感染的速度明显更快 与缺乏淋巴细胞的动物相比，这表明表达 T-bet 的骨髓细胞是宿主生存所必需的。 我们的目标是确定 T-bet 在调节针对弓形虫的骨髓细胞依赖性免疫中的作用。 初步研究结果已确定了一种独特的 T-bet 表达 CD11c+MHCII- 骨髓细胞群，该细胞群是 基于这些结果，我们追踪了骨髓细胞中的 T-bet 表达。 调节弓形虫感染期间的病原体清除和宿主存活为了检验我们的假设，我们将 (i) 确定 T-bet 调节骨髓细胞介导的弓形虫防御的潜在机制 (AIM 1) 和 (ii) 定义表达 T-bet 的骨髓细胞在介导宿主抵抗中的分子功能 我们将利用无偏见的 T-bet 报告小鼠和细胞类型特异性 T-bet 缺陷小鼠。 我们实验室建立的小鼠，结合各种分子生物学技术、光谱细胞术、 这些实验首次将免疫荧光和单细胞 RNA 测序结合在一起。 确定 T-bet 在介导骨髓细胞依赖性宿主针对弓形虫的防御中的作用，从而提供 治疗干预的新的具体目标。