Functional Impact of Stress Granules on Tick-Microbe Interactions

应激颗粒对蜱微生物相互作用的功能影响

• 批准号: 10056116
• 负责人: Dana Kathleen Shaw
• 金额: $ 22.2万
• 依托单位: WASHINGTON STATE UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2020
• 资助国家: 美国
• 起止时间: 2020-06-09 至 2022-05-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/10056116
• 关键词: Anaplasma phagocytophilum; Anaplasmosis; Anti-Bacterial Agents; Antigen-Antibody Complex; Arthropods; Bacterial Infections; Biology; Black-legged Tick; Borrelia burgdorferi; Case Study; Cell physiology; Cells; Cellular Stress; Communities; Cytoplasm; Data; Disease Vectors; Endoplasmic Reticulum; Equilibrium; Eukaryota; Eukaryotic Initiation Factors; Genes; Genetic Transcription; Human; Immune; Immune signaling; Immunity; In Vitro; Incidence; Infection; Intercept; Larva; Lyme Disease; Maintenance; Mammals; Mediating; Microbe; Microscopy; Midgut; Molecular; Outcome; Pathway interactions; Pharmacology; Phosphorylation; Phosphotransferases; Process; Protein Biochemistry; Proteins; RNA; Reporting; Role; Salivary Glands; Signal Transduction; Signaling Protein; Stress; Tick-Borne Diseases; Ticks; Tumor Necrosis Factor Receptor; United States; Vector-transmitted infectious disease; analog; biological adaptation to stress; genetic regulatory protein; granulocyte; human pathogen; in vivo; insight; knock-down; novel; pathogen; pathogenic bacteria; protein kinase R; stress granule; vector; vector competence; vector tick

Abstract Arthropod immunity is a key factor influencing vector competence. We recently identified an atypical Immune Deficiency (IMD) pathway in Ixodes scapularis ticks that responds to and restricts Borrelia burgdorferi (Lyme disease) and Anaplasma phagocytophilum (Human Granulocytic Anaplasmosis). Host cell stress-responses are closely intertwined with immunity and can function to either potentiate or antagonize immune signaling. Whether stress-response pathways intersect with arthropod immunity to influence vector competence remains unknown. Stress Granules (SGs) are aggregates of RNA and protein that transiently form in the cytoplasm of stressed cells, such as during infection. SG formation is highly conserved throughout eukaryotes and has known immune regulatory roles in mammals. Once formed, SGs become cell signaling hubs that can intercept molecules from other pathways to modulate cellular processes. For instance, SGs can inhibit the mammalian analogue to the IMD pathway, the Tumor Necrosis Factor Receptor (TNFR) network, by sequestering signaling proteins away from immune complexes. SGs are induced when eIF2α (eukaryotic translation initiation factor 2α) is phosphorylated by stress-sensing kinases, such as PERK (protein kinase R-like endoplasmic reticulum kinase). In this R21 application, we report that PERK-eIF2α signaling promotes A. phagocytophilum colonization and replication in tick cells. This observation together with known immune inhibitory roles of eIF2α-induced SGs prompted us to look for SG formation in ticks. We found 13 SG-assembly genes that are induced in the salivary glands and/or midguts of A. phagocytophilum-infected ticks. Accordingly, our central hypothesis is that PERK- eIF2α-induced SGs antagonize immune signaling in ticks, which promotes bacterial pathogen colonization. AIM 1 of this proposal will evaluate whether bacterial infection induces SGs in tick cells using immunofluorescent microscopy, protein biochemistry and pharmacological inhibition. AIM 2 will assess the impact of SGs on bacterial colonization and tick immunity in vitro using transcriptional knockdown and pharmacological modulators. AIM 3 will investigate whether SG machinery influences pathogen colonization and maintenance in vivo by using transcriptional knockdown in larvae followed by A. phagocytophilum or B. burgdorferi challenge. As SG formation is a conserved evolutionary mechanism, investigating this phenomenon as it relates to arthropod immunity and vector competence will provide novel insights for the broader vector biology community.

摘要 节肢动物的免疫力是影响媒介能力的关键因素。我们最近发现了一种非典型免疫 肩突硬蜱中应答并限制伯氏疏螺旋体（莱姆病）的IMD缺乏（IMD）途径 疾病）和嗜吞噬细胞无形体（人粒细胞无形体病）。宿主细胞应激反应是 与免疫紧密交织在一起，并且可以起到增强或拮抗免疫信号传导的作用。是否 压力反应途径与节肢动物免疫力交叉影响媒介能力仍然是未知的。 应激颗粒（Stress Granules，SG）是在应激细胞的细胞质中瞬时形成的RNA和蛋白质的聚集体。 细胞，如感染。SG形成在整个真核生物中是高度保守的，并且具有已知的免疫原性。 哺乳动物的调节作用。一旦形成，SGs就成为细胞信号传导中心，可以拦截来自 其他途径来调节细胞过程。例如，SGs可以抑制哺乳动物类似物的表达。 IMD途径，肿瘤坏死因子受体（TNFR）网络，通过隔离信号蛋白 免疫复合物。当eIF 2 α（真核翻译起始因子2α）被诱导时， 在一些实施方案中，所述蛋白质被应激传感激酶如PERK（蛋白激酶R样内质网激酶）磷酸化。 在这个R21申请中，我们报告了PERK-eIF 2 α信号转导促进A.嗜吞噬细胞菌定植， 在蜱细胞中复制。这一观察结果以及eIF 2 α诱导的SG的已知免疫抑制作用 促使我们在蜱虫中寻找SG的形成。我们在唾液中发现了13个SG组装基因， 腺和/或中肠;嗜吞噬细胞菌感染的蜱因此，我们的中心假设是，福利- eIF 2 α诱导的SG拮抗蜱中的免疫信号传导，这促进细菌病原体定殖。 本提案的目的1将使用免疫荧光技术评估细菌感染是否在蜱细胞中诱导SGs 显微镜、蛋白质生物化学和药理学抑制。AIM 2将评估SG对以下方面的影响： 使用转录敲低和药理学方法体外研究细菌定殖和蜱免疫 调制器。目的3将调查是否SG机制影响病原体定植和维护， 体内通过在幼虫中使用转录敲低，然后用A.嗜吞噬细胞菌或B。burgdorferi挑战。 由于SG形成是一种保守的进化机制，因此研究这种现象，因为它与 节肢动物的免疫力和媒介能力将为更广泛的媒介生物学社区提供新的见解。