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Regulation of C. difficile infection by the cytokine interleukin-22 (IL-22)

细胞因子白细胞介素 22 (IL-22) 对艰难梭菌感染的调节

基本信息

批准号：
10341209
负责人：
Lauren A Zenewicz
金额：
$ 26.97万
依托单位：
UNIVERSITY OF OKLAHOMA HLTH SCIENCES CTR
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 2025-01-31
项目状态：
未结题

来源：
https://reporter.nih.gov/project-details/10341209
关键词：
16S ribosomal RNA sequencing Adult Antibiotic Therapy Apoptosis Apoptotic Bacteria Bacterial Infections Biological Products Biology Cell Death Cells Chronic Clostridium difficile Colitis Communicable Diseases Communities Complement Data Disease Epithelial Epithelial Cells Etiology Future Gastrointestinal tract structure Genes Genetic Goals Goblet Cells Guanosine Triphosphate Phosphohydrolases Health Hospitals Immune Immune response Immunity Immunobiology In Vitro Individual Infection Inflammation Inflammatory Bowel Diseases Inflammatory Response Intestines Life Link Lymphocyte MAP Kinase Gene Maintenance Mediating Modeling Monomeric GTP-Binding Proteins Mucous Membrane Mus Oklahoma Organ Organoids Paneth Cells Pathogenesis Pathology Patients Pharmacology Play Population Process Production Proteins Pseudomembranous Colitis Recurrent disease Regulation Relapse Reporter Role STAT3 gene Severities Signal Pathway Signal Transduction Small Interfering RNA Source Therapeutic Tissues Toxic effect Toxin Up-Regulation Villus Virulence Factors Work antimicrobial cell type chronic inflammatory disease commensal bacteria cytokine dysbiosis experimental study gastrointestinal gastrointestinal epithelium gastrointestinal infection high risk in vivo infectious disease treatment inflammatory milieu interest interleukin-22 intestinal epithelium intestinal homeostasis microbial microbiome microbiota mouse model neutralizing antibody pathogen pathogenic bacteria patient subsets prevent programs response stem cells therapeutic target

项目摘要

PROJECT SUMMARY Clostridioides difficile is a mucosal-associated pathogen that can cause life-threatening illness. The bacterium is a leading source of hospital-acquired GI infections, but is emerging in the healthy population. Asymptomatic colonization is common and only leads to productive infection in some individuals, and a subset of these patients will have a relapsing, more severe disease. C. difficile secretes toxin B (TcdB), an inactivator of small GTPases that induces epithelial cell death. This toxin helps C. difficile establish the niche it needs for productive infection. C. difficile requires perturbation in the microbiome to initiate disease. Although recent studies have revealed some means of how it overcomes commensals, we still do not fully understand how C. difficile establishes infection or initiates re-infection. Host immune responses likely play a role. Our long-term goal is to identify how cytokine biology may be therapeutically targeted to alleviate initial C. difficile infection or relapses in high-risk patients. Group 3 innate lymphocytes (ILC3s) are rare immune cells often found in mucosal tissues. They produce high levels of IL-22, a critical modulator of mucosal tissue responses. IL-22 is important for maintaining intestinal homeostasis in health and disease. Through maintenance of the epithelial barrier, the cytokine is protective in GI infections, although the role of IL-22 in C. difficile infection is not clear. In our studies investigating interactions between toxins and ILC3s, we examined the effects of TcdB on IL-22. Our preliminary data show that TcdB induces IL-22 in ILC3s in a GTPase-dependent manner. Pharmacological inhibition suggests that upregulation of IL-22 is through Cdc42. These data form the premise for our hypothesis that C. difficile modulates the host immune response. The overall objective for this application is to understand signaling pathway(s) through which TcdB may modulate ILC3 production of IL-22 and ascertain the benefits of elevated IL-22 to C. difficile during infection. In Aim 1 we will examine how the small GTPase Cdc42 may regulate IL-22 production in activated ILC3s. Through genetic or siRNA-mediated deletion of Cdc42 in ILC3s, we will examine if this small GTPase is a negative regulator of ILC3 activation as well as examine if there are links between Cdc42 and other signaling pathways, including STAT3 and MAPKs. In Aim 2, we will examine the interactions between C. difficile and TcdB, and IL-22 and the GI tissues. We will examine the function of IL- 22 signaling in C. difficile infection using a reductionist approach with colonic organoids. Studies will examine if IL-22 protects against TcdB-mediated apoptosis and identify which IL-22-inducible factors contribute to altering the niche. An in vivo C. difficile infection model will complement in vitro experiments. This study may identify new signaling pathways involved in regulation of IL-22, which is of interest to both the infectious disease and chronic inflammation fields. We will also have a more complete understanding of how increased IL-22 levels modulate the inflammatory environment to favor C. difficile over other bacteria in the GI tract. This has implications on how IL-22 biology may be manipulated in preventing primary or relapsing C. difficile infection.

项目概要艰难梭菌是一种粘膜相关病原体，可导致危及生命的疾病。细菌是医院获得性胃肠道感染的主要来源，但正在健康人群中出现。无症状定植很常见，只会导致某些个体产生生产性感染，其中一部分患者会出现复发、更严重的疾病。艰难梭菌分泌毒素 B (TcdB)，一种小细菌的灭活剂诱导上皮细胞死亡的 GTP 酶。这种毒素有助于艰难梭菌建立其所需的生态位生产性感染。艰难梭菌需要扰动微生物组才能引发疾病。虽然最近研究揭示了它如何克服共生的一些方法，但我们仍然不完全了解 C. 艰难梭菌建立感染或引发再次感染。宿主免疫反应可能发挥了作用。我们的长期目标是确定如何以细胞因子生物学为治疗目标来减轻初始艰难梭菌感染或高危患者复发。第 3 组先天淋巴细胞 (ILC3) 是罕见的免疫细胞，常见于粘膜组织。它们产生高水平的 IL-22，这是粘膜组织反应的关键调节剂。 IL-22 是对于维持健康和疾病中的肠道稳态很重要。通过维护上皮细胞尽管 IL-22 在艰难梭菌感染中的作用尚不清楚，但细胞因子在胃肠道感染中具有保护作用。在我们调查毒素和 ILC3 之间相互作用的研究中，我们检查了 TcdB 对 IL-22 的影响。我们的初步数据表明，TcdB 以 GTPase 依赖性方式在 ILC3 中诱导 IL-22。药理作用抑制表明 IL-22 的上调是通过 Cdc42 实现的。这些数据构成了我们假设的前提艰难梭菌调节宿主免疫反应。该应用程序的总体目标是了解 TcdB 可以通过信号通路调节 ILC3 产生 IL-22 并确定其益处感染期间艰难梭菌的 IL-22 升高。在目标 1 中，我们将研究小型 GTPase Cdc42 如何发挥作用调节激活的 ILC3 中 IL-22 的产生。通过遗传或 siRNA 介导的 ILC3 中 Cdc42 的缺失，我们将检查这个小 GTPase 是否是 ILC3 激活的负调节因子，并检查是否存在 Cdc42 与其他信号通路（包括 STAT3 和 MAPK）之间的联系。在目标 2 中，我们将检查艰难梭菌和 TcdB 以及 IL-22 和胃肠道组织之间的相互作用。我们将检查 IL-的功能使用结肠类器官的还原方法研究艰难梭菌感染中的 22 信号传导。研究将检验是否 IL-22 可以防止 TcdB 介导的细胞凋亡，并确定哪些 IL-22 诱导因子有助于改变利基市场。体内艰难梭菌感染模型将补充体外实验。这项研究可能会确定涉及 IL-22 调节的新信号通路，这对于传染病和慢性炎症领域。我们还将更全面地了解 IL-22 水平如何增加调节炎症环境，使胃肠道中的艰难梭菌优于其他细菌。这有对如何操纵 IL-22 生物学来预防原发性或复发性艰难梭菌感染的影响。