Role of ZBP1 in pathogenesis of Salmonella biofilms

ZBP1 在沙门氏菌生物膜发病机制中的作用

• 批准号: 10658383
• 负责人: SIDDHARTH BALACHANDRAN
• 金额: $ 84.61万
• 依托单位: RESEARCH INST OF FOX CHASE CAN CTR
• 依托单位国家: 美国
• 财政年份: 2023
• 资助国家: 美国
• 起止时间: 2023-05-11 至 2028-04-30
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/10658383
• 关键词: Acute; Amyloid; Ankylosing spondylitis; Autoantibodies; Autoimmunity; B-DNA; Bacterial DNA; Bacterial Infections; Binding; Campylobacter; Cell Death; Cells; Cessation of life; Chronic; Clinical; Complex; DNA; Disease; Epithelial Cells; Fibroblasts; Gastrointestinal tract structure; Generations; Genomic DNA; Human; IL17 gene; Immune; Individual; Industrialization; Infection; Inflammation; Inflammation Mediators; Inflammatory; Interferon Type I; Left; Ligands; Mediating; Microbial Biofilms; Morbidity - disease rate; Mus; Nature; Nucleic Acids; Outcome; Pain; Pathogenesis; Pathway interactions; Patients; Phenotype; Phosphotransferases; Positioning Attribute; Preventive; Process; Production; Protein Secretion; Proteins; RIPK3 gene; RNA; Reiter Disease; Reporting; Role; Salmonella; Salmonella enterica; Salmonella infections; Salmonella typhimurium; Shigella; Signal Transduction; Symptoms; Testing; Therapeutic; Therapeutically Targetable; Viral Proteins; Virus Diseases; Yersinia; Z-Form DNA; acute infection; cell type; chronic infection; chronic inflammatory disease; ds-DNA; enteric infection; enteric pathogen; gastrointestinal symptom; immunogenic; inhibitor; intestinal epithelium; joint inflammation; kinase inhibitor; model organism; mortality; mouse model; mutant; novel therapeutics; prevent; response; sensor; small molecule; systemic inflammatory response

PROJECT SUMMARY Infections with enteric pathogens such as Salmonella, Campylobacter, Shigella, or Yersinia are leading causes of morbidity and mortality worldwide. Although in most individuals the infection resolves, approximately 5% of patients subsequently develop a painful chronic inflammatory condition known as Reactive Arthritis (ReA). How Salmonella infections trigger ReA is not well understood. Using Salmonella enterica serovar Typhimurium (STm) as a model organism, we discovered that a Salmonella protein, curli, is a dominant instigator of inflammation following Salmonella infection. Curli is a secreted protein and major component of the STm biofilm in the gastrointestinal tract. Curli fibrils bind extruded bacterial DNA within the biofilm. It is these curli:DNA complexes, rather than curli alone, that are potent triggers of type I interferon, IL-17, and anti-double stranded DNA autoantibody production, leading to ReA. Unknown, however, is why curli:DNA complexes are so inflammatory. We report in this proposal the remarkable discovery that the DNA present within curli:DNA complexes is not solely B-DNA, the classic right-handed (Watson-Crick) double-helix, but includes copious amounts of left-handed Z-DNA as well. Z-form nucleic acids, such as Z-DNA and Z-RNA, were thought not to readily occur in nature, until we showed last year that Z-RNA is indeed produced during virus infections and is a ligand for the necroptosis-activating host sensor protein ZBP1. Our preliminary results now show that the Z-DNA within curli:DNA complexes activates ZBP1 in intestinal epithelial cells (IECs) and fibroblasts, resulting in RIPK3- dependent necroptosis of these cells. These findings allow us to put forward the hypothesis that Z-DNA within curli:DNA fibrils in Salmonella biofilms activates ZBP1 to instigate RIPK3-dependent necroptosis in intestinal epithelial cells (IECs) and other cell types. Necroptosis, in turn, causes cell loss and disrupts gut barrier integrity, releasing inflammatory mediators that eventually result in autoimmunity and ReA. As necroptosis is a highly inflammatory mode of cell death, these findings, at long last, supply a plausible mechanism for why curli:DNA complexes are hyperinflammatory, and, therefore, for how Salmonella triggers ReA. They also identify Z-DNA as a new PAMP, implicate ZBP1 – until now considered an antiviral protein – as a sensor of bacterial infections, and position RIPK3 inhibitors as unanticipated new therapeutics for the treatment of ReA. In aim 1, we will determine how Z-DNA forms within curli:DNA complexes, and how Z-DNA activates ZBP1. In aim 2, we will identify the ZBP1-driven immune pathways that promote curli:DNA induced inflammation and ReA, and determine the cell types in which ZBP1 signaling is important for pathogenesis. In aim 3, we will evaluate whether necroptosis blockade with RIPK3 kinase inhibitors will have preventive or therapeutic benefit in ReA. A successful outcome to these studies will outline an entirely new mechanism of Salmonella-triggered inflammation. They also stand to open up exciting new therapeutic avenues for Salmonella-induced ReA, with potentially game-changing ramifications for this currently incurable disease.

项目摘要 感染肠道病原体，如沙门氏菌，弯曲杆菌，志贺氏菌，或耶尔森氏菌是主要原因 的发病率和死亡率。虽然在大多数人的感染解决，约5%的 患者随后发展为称为反应性关节炎（ReA）的疼痛性慢性炎症。如何 沙门氏菌感染触发ReA还不清楚。使用肠道沙门氏菌鼠伤寒血清型（STm） 作为一种模式生物，我们发现沙门氏菌的一种蛋白质curli是炎症的主要诱因 沙门氏菌感染后。Curli是一种分泌性蛋白，是STm生物膜的主要成分， 胃肠道卷曲原纤维结合生物膜内挤出的细菌DNA。正是这些卷曲的DNA复合物， 而不是单独的curli，它们是I型干扰素、IL-17和抗双链DNA的有效触发剂， 自身抗体产生，导致ReA。然而，未知的是为什么curli：DNA复合物如此具有炎症性。 我们在这个建议中报告了一个引人注目的发现，即存在于curli：DNA复合物中的DNA不是 只有B-DNA，经典的右手（沃森-克里克）双螺旋，但包括大量的左手 Z-DNA也是。Z型核酸，如Z-DNA和Z-RNA，被认为不容易在自然界中出现， 直到去年，我们才证明Z-RNA确实是在病毒感染过程中产生的，并且是病毒的配体。 坏死性凋亡激活宿主传感器蛋白ZBP 1。我们的初步结果显示， curli：DNA复合物激活肠上皮细胞（IEC）和成纤维细胞中的ZBP 1，导致RIPK 3- 这些细胞的依赖性坏死性凋亡这些发现使我们能够提出假设， curli：沙门氏菌生物膜中的DNA原纤维激活ZBP 1以引发肠道中RIPK 3依赖性坏死性凋亡 上皮细胞（IEC）和其他细胞类型。坏死性凋亡，反过来，导致细胞损失和破坏肠道屏障的完整性， 释放炎症介质，最终导致自身免疫和ReA。由于坏死性凋亡是一种高度 炎症模式的细胞死亡，这些发现，终于提供了一个合理的机制，为什么卷曲：DNA 复合物是高度炎症的，因此，沙门氏菌如何触发ReA。它们还能识别Z-DNA 作为一种新的PAMP，涉及ZBP 1-直到现在被认为是一种抗病毒蛋白-作为细菌感染的传感器， 并将RIPK 3抑制剂定位为治疗ReA的未预料到的新疗法。在目标1中， 确定Z-DNA如何在curli：DNA复合物中形成，以及Z-DNA如何激活ZBP 1。在目标2中，我们 鉴定促进curli：DNA诱导的炎症和ReA的ZBP 1驱动的免疫途径，以及 确定ZBP 1信号传导对发病机制重要的细胞类型。在目标3中，我们将评估 用RIPK 3激酶抑制剂阻断坏死性凋亡将在ReA中具有预防或治疗益处。一 这些研究的成功结果将概述沙门氏菌触发的一种全新的机制， 炎症它们还将为沙门氏菌诱导的ReA开辟令人兴奋的新治疗途径， 对于这种目前无法治愈的疾病来说，这可能会改变游戏规则。