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

基本信息

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
项目类别：
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

项目摘要

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.

项目概要沙门氏菌、弯曲杆菌、志贺氏菌或耶尔森氏菌等肠道病原体感染是主要原因尽管大多数人的感染得到缓解，但大约有 5% 的人感染了这种疾病。患者随后会出现一种痛苦的慢性炎症，称为反应性关节炎 (ReA)。使用肠沙门氏菌鼠伤寒血清型 (STm) 引发沙门氏菌感染尚不清楚。作为模型生物体，我们发现沙门氏菌蛋白 curli 是炎症的主要诱发因素 Curli 是沙门氏菌感染后的一种分泌蛋白，也是 STm 生物膜的主要成分。 Curli 原纤维将挤出的细菌 DNA 结合在生物膜内，这些 Curli：DNA 复合物，不仅仅是 Curli，它们是 I 型干扰素、IL-17 和抗双链 DNA 的有效触发因素然而，导致 ReA 的自身抗体产生却是未知的，这就是 curli:DNA 复合物如此具有炎症性的原因。我们在本提案中报告了一项非凡的发现，即 Curli:DNA 复合物中存在的 DNA 不是仅有 B-DNA，即经典的右手（沃森-克里克）双螺旋，但包含大量的左手DNA Z-DNA 也被认为在自然界中不容易出现，例如 Z-DNA 和 Z-RNA。直到我们去年证明 Z-RNA 确实是在病毒感染过程中产生的，并且是 Z-RNA 的配体我们的初步结果现在表明，坏死性凋亡激活宿主感应蛋白 ZBP1。 curli：DNA 复合物激活肠上皮细胞 (IEC) 和成纤维细胞中的 ZBP1，从而产生 RIPK3- 这些发现使我们能够提出 Z-DNA 存在于这些细胞中的假设。 curli：沙门氏菌生物膜中的 DNA 原纤维激活 ZBP1 以引发肠道中 RIPK3 依赖性坏死性凋亡上皮细胞（IEC）和其他细胞类型的坏死反过来会导致细胞损失并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，因为坏死性凋亡是一种高度严重的疾病。细胞死亡的炎症模式，这些发现最终为 curli:DNA 的原因提供了一个合理的机制复合物是高度炎症的，因此，对于沙门氏菌如何触发 ReA，它们也可以识别 Z-DNA。作为一种新的 PAMP，将 ZBP1（迄今为止被认为是一种抗病毒蛋白）作为细菌感染的传感器，并将 RIPK3 抑制剂定位为治疗 ReA 的意想不到的新疗法。在目标 1 中，我们将。确定 Z-DNA 在 curli:DNA 复合物中如何形成，以及 Z-DNA 如何激活 ZBP1 在目标 2 中，我们将。确定 ZBP1 驱动的免疫途径，促进 curli:DNA 诱导的炎症和 ReA，以及确定 ZBP1 信号传导对发病机制起重要作用的细胞类型在目标 3 中，我们将评估是否存在这种情况。使用 RIPK3 激酶抑制剂阻断坏死性凋亡将对 ReA 具有预防或治疗作用。这些研究的成功结果将概述沙门氏菌引发的全新机制他们还致力于为沙门氏菌诱导的 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，可能会产生改变游戏规则的后果。