Intestinal granuloma formation during Yersinia pseudotuberculosis infection

假结核耶尔森菌感染期间肠道肉芽肿的形成

• 批准号: 10614650
• 负责人: RINA MATSUDA
• 金额: $ 0.58万
• 依托单位: UNIVERSITY OF PENNSYLVANIA
• 依托单位国家: 美国
• 财政年份: 2021
• 资助国家: 美国
• 起止时间: 2021-05-01 至 2023-05-15
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/10614650
• 关键词: Ablation; Acute; Animals; Bacteria; Biological Models; Cell physiology; Cells; Chronic; Chronic Disease; Communicable Diseases; Crohn' s disease; Cytosol; Data; Defect; Diagnostic; Disease; Disease model; Encapsulated; Exhibits; Future; Gastroenteritis; Gene Expression; Genetic; Granuloma; Granulomatous disease; Histologic; Host Defense; Human; Immune; Immune response; Immunocompetent; Immunologic Stimulation; Immunologics; Immunotherapy; Infection; Inflammatory; Injections; Integration Host Factors; Intestinal Mucosa; Intestines; Invaded; Knowledge; Liver; Lung; Lymphadenitis; Lymphoid Tissue; Mediating; Modeling; Mus; Mutation; Needles; Oral; Organ; Outcome; Pasteurella pseudotuberculosis; Pathologic; Patients; Peripheral; Phagocytes; Phagocytosis; Plague; Plasmids; Play; Proteins; Receptor Signaling; Reporter; Rodent; Role; Sarcoidosis; Side; Signal Transduction; Site; Source; Spleen; Structure; System; TNF gene; Testing; Therapeutic; Time; Tissues; Tumor Necrosis Factor Receptor; Type III Secretion System Pathway; Virulence; Virulence Factors; Work; Yersinia; Yersinia infections; Yersinia pseudotuberculosis Infections; acute infection; chronic infection; cytokine; enteric infection; experimental study; human pathogen; immune function; improved; insight; lymph nodes; lymphoid organ; microbicide; monocyte; mortality; mouse model; mutant; neutrophil; novel; pathogen; pathogenic bacteria; prevent; recruit; response; therapeutic target; transmission process

Project Summary/Abstract In various infectious and non-infectious contexts, chronic immune stimulation induces the formation of granulomas: aggregations of recruited immune cells that are thought to encapsulate pathogens and prevent their dissemination. Despite being a prominent feature of numerous infections, key gaps in our knowledge are the mechanisms of granuloma formation and the functional role of these structures in controlling infectious disease. Yersinia are bacterial pathogens that block immune cell function and induce granuloma formation in lymphoid tissues. Yersinia pseudotuberculosis (Yptb) causes self-limiting gastroenteritis and lymphadenitis in immunocompetent hosts following fecal-oral transmission. Yptb subverts the immune response through the injection of Yersinia outer proteins (Yops) into nearby immune cells through a needle-like type III secretion system, blocking functions such as phagocytosis and pro-inflammatory gene expression. While granulomas are well-described during Yersinia infection of lymphatic tissue, relatively little is known about early intestinal infection. In this proposal, we describe, for the first time, a murine model of granuloma formation in the intestinal mucosa during acute Yptb infection. Importantly, live bacteria are abundant within granulomas but are largely absent from surrounding non-granuloma intestinal tissue, suggesting that granulomas play a previously uncharacterized role at the intestinal mucosa, an immunological barrier that bottlenecks Yersinia dissemination. Interestingly, Yptb lacking Yops does not induce intestinal granuloma formation, suggesting that these structures form in response to features of bacterial virulence. Further, intestinal granulomas are highly enriched in neutrophils and inflammatory monocytes. Strikingly, monocyte-deficient Ccr2- /- mice show defects in restriction of bacterial dissemination, succumbing to acute infection. Similarly, mice deficient in tumor necrosis factor (TNF) signaling, a cytokine that enhances phagocyte microbicidal function, exhibit defects in bacterial restriction. I therefore hypothesize that blockade of immune cell function by Yop effector proteins induces the formation of intestinal granulomas, which protect the host through bacterial restriction mediated by monocyte-derived TNF. In this proposal, I will investigate the formation and function of intestinal granulomas from both the bacterial and host sides. First, I will uncover how Yersinia virulence factors induce intestinal granuloma formation by testing a panel of Yop mutant strains, in addition to using an injection reporter strain (Aim 1). Second, I will dissect immune cell functions that are necessary for restriction of Yersinia by intestinal granulomas through complementary mechanistic studies using chimeric animals and genetic ablation systems (Aim 2). This work will mechanistically define a previously unappreciated facet of the host immune response to Yersinia infection. Findings from this novel model of intestinal granuloma formation will provide insight into future work on poorly-studied granulomatous disorders and underscore potential therapeutic targets for the treatment of chronic disease.

项目摘要/摘要 在各种感染和非感染的情况下，慢性免疫刺激诱导形成 肉芽肿：被认为包裹病原体并防止其死亡的免疫细胞的聚集体。 传播。尽管是众多感染的一个显著特征，但我们知识中的主要差距是 肉芽肿的形成机制及其在控制中的作用 传染病。耶尔森氏菌是一种细菌病原体，可阻断免疫细胞功能并导致肉芽肿。 在淋巴组织中形成。假结核耶尔森氏菌(Yptb)可引起自限性胃肠炎和 粪口传播后免疫功能正常宿主的淋巴结炎。Yptb颠覆免疫反应 通过针状III型将耶尔森氏菌外部蛋白(YOPs)注射到附近的免疫细胞中 分泌系统，阻断吞噬和促炎基因表达等功能。而当 肉芽肿在耶尔森氏菌感染淋巴组织的过程中被很好地描述，对早期的了解相对较少。 肠道感染。在这个方案中，我们首次描述了一种肉芽肿形成的小鼠模型。 在急性Yptb感染期间的肠道粘膜中。重要的是，体内有大量活细菌 肉芽肿，但在周围的非肉芽肿肠道组织中基本不存在，提示肉芽肿 在肠粘膜扮演着以前没有描述过的角色，这是一种免疫屏障，阻碍了 耶尔西尼亚病毒传播。有趣的是，Yptb缺乏YOPs并不会导致肠道肉芽肿的形成， 这表明这些结构的形成是对细菌毒力特征的响应。此外，肠道 肉芽肿高度富含中性粒细胞和炎性单核细胞。引人注目的是，缺乏单核细胞的CCR2- /-小鼠在限制细菌传播方面存在缺陷，死于急性感染。类似地，老鼠 缺乏肿瘤坏死因子信号，这是一种增强吞噬细胞杀菌功能的细胞因子， 在细菌限制方面表现出缺陷。因此，我假设YOP对免疫细胞功能的阻断 效应蛋白诱导肠道肉芽肿的形成，通过 单核细胞来源的肿瘤坏死因子介导的细菌限制。在这项提议中，我将调查形成和 肠道肉芽肿的功能从细菌和宿主两方面。首先，我将揭开耶尔西尼亚是如何 毒力因子通过测试一组YOP突变菌株来诱导肠道肉芽肿的形成，除了 使用注射报告菌株(目标1)。其次，我将剖析免疫细胞功能，这些功能是 利用嵌合体互补机制研究肠道肉芽肿对耶尔森菌的抑制作用 动物和基因消融系统(目标2)。这项工作将机械地定义以前未被赏识的 耶尔森氏菌感染后宿主免疫反应的一个方面。这一新的肠道肉芽肿模型的发现 形成将提供对研究较少的肉芽肿性疾病的未来工作的洞察，并下划线 慢性病治疗的潜在治疗靶点。