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Innate immunity and inflammatory response of macrophages to Legionella infection

巨噬细胞对军团菌感染的先天免疫和炎症反应

基本信息

批准号：
10466923
负责人：
Yousef A Abu Kwaik
金额：
$ 38.25万
依托单位：
UNIVERSITY OF LOUISVILLE
依托单位国家：
美国
项目类别：
财政年份：
2018
资助国家：
美国
起止时间：
2018-09-14 至 2024-08-31
项目状态：
已结题

来源：
https://reporter.nih.gov/project-details/10466923
关键词：
3-Dimensional Adaptor Signaling Protein Amylases Animal Model Anti-Inflammatory Agents Attenuated Bacterial Infections Binding Bypass Case Study Crystallization Cytosol Data Exhibits Glucose Glycogen Glycolysis Growth Human Immune In Vitro Infection Infection Control Inflammatory Inflammatory Response Innate Immune Response Knowledge Legionella Legionella pneumophila Legionnaires&apos Disease Lung Lysosomes Macrophage Activation Mediating Membrane Metabolism Morbidity - disease rate Mus Natural Immunity Pathway interactions Phenotype Phosphotyrosine Proteins Role Side Signal Transduction Structure Surface Testing Up-Regulation Vacuole aerobic glycolysis arm community acquired pneumonia cytokine diabetic patient in vivo innate immune mechanisms innate immune pathways macrophage monocyte mortality mutant novel pathogen pathogenic bacteria response

项目摘要

Project Summary Depending on the signals in vitro, macrophages can undergo transient and reversible differentiation into two main subsets: pro-inflammatory “M1” (classically activated) or anti-inflammatory “M2” (alternatively activated) phenotype. Upon exposure of macrophages to high levels of glucose in vitro or in diabetic patients in vivo, they undergo differentiation and activation into a M1 pro-inflammatory state, which produces pro-inflammatory cytokines mediated by cellular reprogramming of metabolism through upregulating aerobic glycolysis. The M1 pro-inflammatory differentiation of macrophages is an import arm of the innate immune response to control bacterial infections. Our preliminary data show that when macrophages engulf the intracellular bacterial pathogen Legionella pneumophila (Lp), they rapidly respond by differentiation into an activated M1-like pro-inflammatory phenotype. Despite this rapid macrophage pro-inflammatory activation, the Legionella-containing vacuole (LCV) bypasses macrophage activation by limiting its fusion to lysosomes. We show that the early M1-like pro-inflammatory differentiation of human monocytes-derived macrophages (hMDMs) to Lp is an innate immune response to cytosolic hyper-glucose generated through rapid degradation of glycogen by the injected Legionella amylase (LamA) effector. We discovered that Lp has evolved a lysosomal degradation bypass pathway within the pro-inflammatory hMDMs by injecting the MavE effector, which becomes localized in a micro-domain on the cytosolic side of the LCV membrane. The mavE-deficient mutant is targeted by hMDMs to the lysosomes for degradation, and the mutant is totally attenuated in vitro and in vivo. We have resolved the novel three dimensional crystal structure of MavE, which shows a cytosolic surface-exposed domain with an NPxY eukaryotic motif involved in binding to phosphotyrosine-binding adaptor proteins. Our central hypothesis is: the M1-like pro- inflammatory activation of hMDMs to Lp infection is an innate immune response to the cytosolic hyper-glucose elicited by LamA, and the pathogen utilizes MavE to bypass the innate immune macrophage pathway of lysosomal degradation. To test the hypothesis, our specific aims are: Specific Aim I: The mechanisms of M1-like pro-inflammatory differentiation of hMDMs in response to the effect of LamA; and Specific Aim II: The mechanisms of evasion of the innate macrophage function of lysosomal degradation through utilization of a lysosomes bypass pathway mediated by MavE. Upon completion of our proposed studies, we will discover the mechanism of the innate pro-inflammatory response of macrophages to Lp and the lysosomal degradation bypass pathway maneuvered by the pathogen to avoid a fatal fate.

项目概要根据体外信号，巨噬细胞可以经历短暂和可逆的分化分为两个主要子集：促炎“M1”（经典激活）或抗炎“M2” （选择性激活）表型。巨噬细胞在体外暴露于高水平的葡萄糖后或者在糖尿病患者体内，它们会分化并激活为 M1 促炎细胞状态，产生由细胞代谢重编程介导的促炎细胞因子通过上调有氧糖酵解。巨噬细胞的M1促炎分化是控制细菌感染的先天免疫反应的重要手段。我们的初步数据表明当巨噬细胞吞噬细胞内细菌病原体嗜肺军团菌时 (Lp)，它们通过分化成激活的 M1 样促炎表型来快速做出反应。尽管巨噬细胞快速促炎激活，含有军团菌的液泡 (LCV) 通过限制巨噬细胞与溶酶体的融合来绕过巨噬细胞激活。我们表明，早期人单核细胞来源的巨噬细胞 (hMDM) 的 M1 样促炎分化 Lp 是对胞质高葡萄糖的先天免疫反应，通过快速降解产生注射的军团菌淀粉酶 (LamA) 效应子产生的糖原。我们发现Lp进化出了通过注射 MavE 绕过促炎 hMDM 内的溶酶体降解途径效应器，其定位于 LCV 膜胞质侧的微域中。 mavE 缺陷突变体被 hMDM 靶向溶酶体进行降解，突变体在体外和体内均完全减弱。我们已经解决了新颖的三维晶体结构 MavE 的图，显示了一个胞质表面暴露的结构域，其中涉及 NPxY 真核基序与磷酸酪氨酸结合接头蛋白的结合。我们的中心假设是：类似 M1 的亲 hMDM 对 Lp 感染的炎症激活是对细胞质的先天免疫反应 LamA 引起高血糖，病原体利用 MavE 绕过先天免疫巨噬细胞溶酶体降解途径。为了检验这个假设，我们的具体目标是：具体目标 I： hMDM 的 M1 样促炎分化机制对 LamA 效应的反应；和具体目标二：先天性的逃避机制巨噬细胞通过利用溶酶体旁路进行溶酶体降解的功能 MavE 介导的途径。完成我们提议的研究后，我们将发现巨噬细胞对 Lp 和溶酶体的先天促炎反应机制病原体操纵降解旁路途径以避免致命的命运。