Molecular basis of Wnt activation by Ehrlichia Wnt ligand mimics

埃里希体Wnt配体模拟物激活Wnt的分子基础

基本信息

批准号：
10117073
负责人：
JERE W MCBRIDE
金额：
$ 19.34万
依托单位：
UNIVERSITY OF TEXAS MED BR GALVESTON
依托单位国家：
美国
项目类别：
财政年份：
2020
资助国家：
美国
起止时间：
2020-03-01 至 2023-02-28
项目状态：
已结题

来源：
https://reporter.nih.gov/project-details/10117073
关键词：
Actins Amino Acid Motifs Antibiotics Automobile Driving Autophagocytosis Bacteria Bacterial Adhesins Bacterial Infections Binding Case Study Cell Polarity Cell Surface Proteins Cells Centers for Disease Control and Prevention (U.S.)Complex DNA Data Development Development Polarity Doxycycline Drug resistance Ehrlichia Ehrlichia chaffeensis Ehrlichiosis Emerging Communicable Diseases Event Family Fever Genetic Transcription Goals Growth Health Host Defense Host Defense Mechanism Human Infection Investigation Knowledge Laboratories Life Ligands Lysosomes Membrane Membrane Microdomains Membrane Proteins Modeling Molecular Mononuclear National Institute of Allergy and Infectious Disease Natural Immunity Pathway interactions Phagocytes Phagocytosis Phagocytosis Induction Physiological Proteins Receptor Cell Receptor Signaling Recombinants Reporting Research Rifampin Role Signal Pathway Signal Transduction Surface System Tandem Repeat Sequences Tertiary Protein Structure Therapeutic Therapeutic Studies Tick-Borne Diseases Toxic Shock Syndrome Undifferentiated United States Vacuole Virulence WNT Signaling Pathway Wnt proteins antimicrobial beta catenin combat cytokine insight mimetics mimicry monocyte novel pathogen polymerization protein E receptor response therapeutic target transcription factor uptake

项目摘要

Project Summary Ehrlichia chaffeensis (E. ch.) is a gram-negative, obligately intracellular bacterium and causative agent of the most prevalent life-threatening tick-borne disease in the United States, human monocytic ehrlichiosis (HME). Wnt signaling is a conserved eukaryotic signal cascade comprising canonical and noncanonical pathways that regulate events including cell fate, development, and cell polarity, as well as innate immunity-associated events such as autophagy, cytokine expression, and phagocytosis. Our laboratory has shown that during infection, E. ch. activates conserved eukaryotic signaling pathways including both canonical and noncanonical Wnt signaling. Wnt signaling enhances E. ch. intracellular survival by driving bacterial uptake and inhibiting fusion of the ehrlichial replicative vacuole with the lysosome. Although these studies have identified Wnt pathway activation as a virulence strategy for E. ch., identification of an activating event for the observed phenomena remains a critical gap in knowledge. Under normal physiological conditions, Wnt signaling- dependent phagocytosis is initiated through the binding of a Wnt ligand to one of 10 Frizzled (Fzd). Our preliminary data demonstrates that E. ch. surface protein TRP120 directly binds a Fzd, possesses homology with the conserved family of Wnt proteins, and can stimulate activation of the Wnt transcription factor β- catenin. We have also shown that inhibition of Wnt signaling blocks ehrlichial entry, indicating E. ch. effectively establishes infection through activation of Wnt-dependent phagocytosis. The long-term goal of this project is to utilize E. ch. manipulation of monocyte Wnt signaling as a model to study the therapeutic potential of harnessing Wnt signaling during human intracellular bacterial infection. The objective of this proposal is to define the bacterial ligand and eukaryotic receptor determinants of E. ch. effector-driven activation of Wnt signaling and entry into monocytes. We hypothesize that ehrlichial TRPs are Wnt ligand mimetics that signal through Wnt pathway receptor-coreceptor pairs for activation of canonical and noncanonical Wnt signaling to enhance bacterial host cell entry and intracellular survival. In specific aim 1, we will investigate ehrlichial TRP Wnt ligand mimetic activation of canonical and noncanonical Wnt signaling. In specific aim 2, we will define the role of Wnt pathway receptors and coreceptors in ehrlichial TRP-driven Wnt signaling activation during infection. This research will provide insight to evolutionarily conserved eukaryotic pathways that pathogens have evolved to utilize for cell invasion and intracellular growth. Our approach to identifying a level at which Wnt signaling can be hijacked by intracellular pathogens will provide mechanisms for previously observed phenomena as well as potential antimicrobial therapeutic targets

项目概要恰菲埃里希体 (E. ch.) 是一种革兰氏阴性、专性细胞内细菌，也是该病的病原体。美国最常见的危及生命的蜱传疾病是人类单核埃利希体病 (HME)。 Wnt 信号传导是一种保守的真核信号级联，包含经典和非经典途径，调节包括细胞命运、发育和细胞极性以及先天免疫相关的事件我们的实验室已经证明，自噬、细胞因子表达和吞噬作用等事件。感染，E. ch. 激活保守的真核信号通路，包括经典和非经典信号通路 Wnt 信号传导通过驱动细菌摄取和抑制来增强大肠杆菌的细胞内存活。尽管这些研究已经鉴定出Wnt，但埃立克体复制液泡与溶酶体的融合。途径激活作为大肠杆菌的毒力策略，识别观察到的激活事件在正常生理条件下，Wnt 信号传导仍然是一个关键的知识空白。依赖性吞噬作用是通过 Wnt 配体与 10 个卷曲蛋白 (Fzd) 之一的结合而启动的。初步数据表明 E. ch. 表面蛋白 TRP120 直接结合 Fzd，具有同源性与 Wnt 蛋白保守家族一起，可以刺激 Wnt 转录因子 β- 的激活我们还表明，抑制 Wnt 信号传导可以有效阻止埃利希体进入。通过激活 Wnt 依赖性吞噬作用来建立感染该项目的长期目标是 E. ch. 操纵单核细胞 Wnt 信号传导作为研究治疗潜力的模型在人类细胞内细菌感染过程中利用 Wnt 信号传导。定义 E. ch 效应子驱动的 Wnt 激活的细菌配体和真核受体决定因素。我们勇敢地承认埃利希体 TRP 是发出信号的 Wnt 配体模拟物。通过 Wnt 通路受体-辅助受体对激活经典和非经典 Wnt 信号传导增强宿主细菌细胞进入和细胞内存活在具体目标 1 中，我们将研究埃里希体 TRP。典型和非典型 Wnt 信号传导的 Wnt 配体模拟激活在具体目标 2 中，我们将定义 Wnt 通路受体和辅助受体在埃立克体 TRP 驱动的 Wnt 信号激活中的作用这项研究将深入了解病原体在进化上保守的真核途径。我们的方法已经发展到可用于细胞侵袭和细胞内生长。 Wnt信号可以被细胞内病原体劫持，这将为之前观察到的机制提供机制现象以及潜在的抗菌治疗靶点