The role of tumor progression locus 2 (TPL2) in the pathogenesis of Clostridium difficile infection (CDI)

肿瘤进展基因座 2 (TPL2) 在艰难梭菌感染 (CDI) 发病机制中的作用

• 批准号: 9227819
• 负责人: Xingmin Sun
• 金额: $ 7.68万
• 依托单位: UNIVERSITY OF SOUTH FLORIDA
• 依托单位国家: 美国
• 财政年份: 2017
• 资助国家: 美国
• 起止时间: 2017-04-15 至 2019-03-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/9227819
• 关键词: Ablation; Bone Marrow; C-terminal; CDC42 gene; Caspase; Cells; Centers for Disease Control and Prevention (U.S.); Cessation of life; Clostridium difficile; Cytoskeleton; Cytosol; Dendritic Cells; Diarrhea; Disease; Enterocolitis; Exotoxins; Glucosyltransferase; Goals; Healthcare; IL8 gene; In Vitro; Incidence; Infection; Inflammation; Inflammatory; Inflammatory Bowel Diseases; Inflammatory Response; Inflammatory disease of the intestine; Injury; Interleukin-1 beta; Interleukin-6; Intervention; Intestines; Knock-out; Knockout Mice; Knowledge; Laboratories; Lesion; MAP Kinase Gene; MAP3K8 gene; MAPK14 gene; MAPK8 gene; Mediating; Metronidazole; Mitogen-Activated Protein Kinases; Morbidity - disease rate; N-terminal; Natural Immunity; Pathogenesis; Patients; Play; Process; Production; Protein-Serine-Threonine Kinases; Recurrence; Reporting; Resistance; Role; Severities; Signal Pathway; Signal Transduction; Structure; Symptoms; TNF gene; TNFRSF1A gene; Testing; Tight Junctions; Tissues; Toxin; Vancomycin; Wild Type Mouse; adaptive immunity; base; chemokine; cytokine; design; immunological intervention; in vivo; inhibitor/antagonist; macrophage; mortality; mouse model; new therapeutic target; public health emergency; receptor binding; response; rho GTP-Binding Proteins

Project Summary/Abstract C. difficile infection (CDI) is the most common cause of infectious diarrhea in healthcare settings with about 453.000 cases and 29,000 deaths yearly in US per CDC report in 2015. A continual rise in severe CDI has been observed worldwide due to the emergence of hypervirulent strains. CDI symptoms range from diarrhea to intestinal inflammation/lesion and death. Symptoms are mainly caused by two exotoxins TcdA and TcdB, which glucosylate Rho GTPases, including RhoA, Rac1 and CDC42 within cells, leading to disruption of cytoskeleton and tight junctions. Both toxins share similar domain structures, including the N-terminal glucosyltransferase domain (GT), the autocatalytic cysteine proteinase domain (CPD), the translocation domain (TMD), and the C-terminal receptor binding domain (RBD). Only the GT is released into cytosol after auto-cleavage of the toxin by its CPD. The course of CDI is characterized by an initial intestinal inflammatory process followed by a systemic inflammatory response. However, the mechanism by which TcdA/TcdB induce a potent inflammatory response, the hallmark of the disease, is unclear. Our long-term goal is to understand the mechanisms mediating intestinal inflammation by C. difficile toxins and to utilize this knowledge for designing better interventions to reduce the incidence and severity of CDI. The objective of this study is to elucidate the role of TPL2 in the pathogenesis of CDI. We hypothesize that TPL2 ablation will down regulate TcdA/TcdB-induced activation of MAPK, leading to reduced TNF-α / IL-6 production, thus reducing toxin-caused intestinal inflammation, tissue injury and mortality. To test our hypothesis, two specific aims will be pursued. In aim 1, we will evaluate the role of TPL2 in the pathogenesis of CDI using mouse models. In aim 2, we will investigate the role of TPL2 in the signaling pathway mediating TcdA/TcdB-induced production of TNF-α and IL-6 by bone marrow-derived macrophages.

项目总结/摘要 C.艰难梭菌感染（CDI）是医疗机构中感染性腹泻的最常见原因， 根据CDC报告，2015年美国每年有453，000例病例和29，000例死亡。严重的CDI持续上升， 由于高毒力菌株的出现，在世界范围内观察到。CDI症状范围从腹泻到 肠道炎症/病变和死亡。症状主要由两种外毒素TcdA和TcdB引起， 使细胞内的Rho GTPases（包括RhoA、Rac 1和CDC 42）发生葡萄糖基化，导致细胞内的Rho GTPases被破坏 细胞骨架和紧密连接。两种毒素具有相似的结构域结构，包括N-末端 葡萄糖基转移酶结构域（GT），自催化半胱氨酸蛋白酶结构域（CPD），易位 结构域（TMD）和C-末端受体结合结构域（RBD）。只有GT被释放到胞质溶胶后， CDI的过程的特点是初始的肠道炎症反应， 这是一个全身性炎症反应的过程。然而，TcdA/TcdB诱导的机制是， 这种疾病的标志是一种强有力的炎症反应，目前还不清楚。 我们的长期目标是了解C.艰难梭菌毒素和 利用这些知识来设计更好的干预措施，以减少CDI的发病率和严重程度。 本研究的目的是阐明TPL 2在CDI发病机制中的作用。我们假设 TPL 2阻断可下调TcdA/TcdB诱导的MAPK活化，导致TNF-α / IL-6降低 因此，减少毒素引起的肠道炎症、组织损伤和死亡率。 为了检验我们的假设，我们将追求两个具体目标。在目标1中，我们将评估TPL 2在 使用小鼠模型研究CDI的发病机制。在目的2中，我们将研究TPL 2在信号转导中的作用。 TcdA/TcdB介导的骨髓源性巨噬细胞产生TNF-α和IL-6的途径。