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

• 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
• 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

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

项目摘要 查菲埃利希菌Ehrlichiachaffesis(E.ch.)是一种革兰氏阴性、专性胞内细菌，也是 在美国，最流行的威胁生命的扁虱传播疾病是人类单核细胞埃立克体病(HME)。 WNT信号是一个保守的真核信号级联，包括规范和非规范途径， 调节包括细胞命运、发育和细胞极性在内的事件，以及与先天免疫相关的 自噬、细胞因子表达和吞噬等事件。我们的实验室已经证明，在 感染，E.ch.激活保守的真核信号通路，包括规范和非规范 WNT信令。WNT信号增强E.ch。通过促进细菌摄取和抑制细菌在细胞内存活 埃利希复制液泡与溶酶体融合。尽管这些研究已经确定了WNT 途径激活作为E.ch的毒力策略，识别观察到的激活事件 现象仍然是知识中的一个关键差距。在正常生理条件下，Wnt信号- 依赖的吞噬作用是通过Wnt配体与10个FrizzledFZD中的一个结合而启动的。我们的 初步数据表明，E.ch.表面蛋白TRP120直接与FZD结合，具有同源性 与保守的Wnt蛋白家族结合，并能刺激Wnt转录因子β- 连锁素。我们还表明，抑制Wnt信号可以阻止细菌进入，这表明E.ch。有效地 通过激活依赖于Wnt的吞噬作用来建立感染。这个项目的长期目标是 利用E.ch。以单核细胞Wnt信号调控为模型研究其治疗潜力 在人类细胞内细菌感染过程中利用Wnt信号。这项建议的目的是 确定E.ch的细菌配体和真核受体决定因素。效应器驱动的Wnt激活 信号和进入单核细胞。我们假设Ehrlichial TRP是模拟该信号的Wnt配体 通过Wnt通路受体-辅受体对激活规范和非规范Wnt信号转导 促进细菌宿主细胞进入和细胞内存活。在特定的目标1中，我们将研究艾尔利希色氨酸 WNT配体模拟激活规范和非规范的WNT信号。在具体目标2中，我们将定义 Wnt通路受体和辅受体在Ehrlical Trp介导的Wnt信号激活中的作用 感染。这项研究将为进化上保守的真核生物途径提供洞察力 已经进化成用于细胞入侵和细胞内生长。我们确定一个级别的方法是 WNT信号可被细胞内病原体劫持将为先前观察到的机制提供依据 现象及潜在的抗菌治疗靶点