The impact of ER stress on Salmonella Typhimurium infections

内质网应激对鼠伤寒沙门氏菌感染的影响

基本信息

批准号：
10708073
负责人：
Arina Marijke Keestra-Gounder
金额：
$ 38.1万
依托单位：
UNIVERSITY OF COLORADO DENVER
依托单位国家：
美国
项目类别：
财政年份：
2022
资助国家：
美国
起止时间：
2022-09-20 至 2027-07-31
项目状态：
未结题

来源：
https://reporter.nih.gov/project-details/10708073
关键词：
ATF6 gene Actins Apoptosis Apoptotic Autophagocytosis Bacterial Infections Binding Biological Process Calcium Calcium Signaling Cell Death Induction Cell physiology Cells Colitis Complex Cytoskeleton Data Development Endoplasmic Reticulum Epithelial Cells Functional disorder Future Gastroenteritis Gastrointestinal tract structure Gene Expression Gene Targeting Genes Gram-Negative Bacteria Homeostasis Human Immune response Immune signaling Immunologic Receptors In Vitro Induction of Apoptosis Infection Inflammation Inflammatory Inflammatory Bowel Diseases Inflammatory Response Intervention Intestines Ligands Link Lipids Mediating Membrane Modeling Mus Mutant Strains Mice Mutation Nutrient Pathogenesis Pathology Pathway interactions Pattern recognition receptor Peptidoglycan Play Population Predisposition Process Protein Inhibition Proteins Regulation Resistance Resources Role Salmonella Salmonella infections Salmonella typhimurium Signal Transduction Source Streptomycin Testing Therapeutic Translations Work XBP1 gene biological adaptation to stress conditional mutant dextran sulfate sodium induced colitis endoplasmic reticulum stress experimental study gut inflammation interest intestinal epithelium microbiota monocyte pathogen protein complex protein misfolding receptor release of sequestered calcium ion into cytoplasm response sphingosine 1-phosphate tissue/cell culture

项目摘要

Project Summary NOD1 and NOD2 are Pattern Recognition Receptors that sense fragments of bacterial peptidoglycans, and are able to detect perturbations in cellular processes such as the regulation of the actin cytoskeleton and disturbance in endoplasmic reticulum (ER) homeostasis. Under different stressful conditions, such as bacterial infections, protein misfolding and perturbations in calcium homeostasis, the ER is unable to maintain homeostasis and activates the unfolded protein response (UPR). Within the UPR three transmembrane receptors, IRE1α, PERK and ATF6, are activated and regulate biological processes such as inhibition of protein translation, autophagy, and inflammation to reestablish cellular homeostasis. NOD1 and NOD2 have been implicated in ER stress- induced inflammation, by acting downstream of IRE1α in the UPR to induce inflammatory responses. This link between the UPR and NOD1/2 signaling is of particular interest in intestinal inflammation since mutations in genes associated with the UPR (XBP1) and innate immune signaling (NOD2) have been associated with intestinal epithelial cell (IEC) dysfunction in intestinal inflammatory diseases. Salmonella Typhimurium (S. Tm) is a gram-negative bacterium that induces robust inflammation, partially dependent on NOD1/2 activation, of the intestinal epithelium resulting in gastroenteritis. As a survival mechanism, S. Tm has adapted to these inflammatory conditions in the intestinal tract by utilizing products of inflammation as a nutrient source to outcompete the resident microbiota. Considering the importance of ER stress in intestinal inflammation and the fact that S. Tm is a major cause of gastroenteritis, it is surprising that ER stress in the context of Salmonella infections is significantly underexplored. Furthermore, it is currently unknown whether S. Tm can exploit ER stress-induced inflammation resulting in luminal expansion. Our objectives are to investigate the link between ER stress and inflammation in the S. Tm-induced colitis model. Our central hypothesis is that activation of the ER stress response in the gastrointestinal tract contributes significantly to S. Tm-induced inflammation, luminal expansion and pathology. We will test our hypothesis by pursuing the following three aims. 1) Determine the contribution of calcium flux and UPR activation to NOD1/2 signaling. In in vitro experiments we will determine which branches of the UPR, in conjunction with dysregulation of calcium signaling, contributes to NOD1/2 activation. 2) Determine the role of CHOP in the S. Tm-induced colitis model. Using Chop-/- mice and conditional mutant mice we will investigate the role of CHOP in S. Tm-induced inflammation and outgrowth. 3) Determine the role of NOD1/2 and IRE1α in response to S. Tm. We will investigate the role of IRE1α in Nod1/2-/- mice in the S. Tm-induced colitis model. Characterizing the mechanisms downstream of the UPR that orchestrate ER stress-induced responses is necessary to safely modulate this process for the development of future therapeutics and will significantly increase our understanding in Salmonella pathogenesis.

项目概要 NOD1 和 NOD2 是模式识别受体，可感知细菌肽聚糖片段，并能够检测细胞过程中的扰动，例如肌动蛋白细胞骨架的调节和不同应激条件下（例如细菌感染）内质网 (ER) 稳态的紊乱。、蛋白质错误折叠和钙稳态扰动，ER 无法维持稳态并激活未折叠的蛋白质反应(UPR) 在 UPR 中，IRE1α、PERK 和 ATF6 三种跨膜受体被激活并调节生物过程，例如抑制蛋白质翻译、自噬、 NOD1 和 NOD2 通过作用于 UPR 中 IRE1α 的下游来诱导炎症反应，从而参与了 ER 应激诱导的炎症反应。因为与 UPR (XBP1) 和先天免疫信号 (NOD2) 相关的基因突变与沙门氏菌肠道炎症性疾病中的肠上皮细胞 (IEC) 功能障碍有关。鼠伤寒杆菌 (S. Tm) 是一种革兰氏阴性细菌，可引起肠上皮强烈炎症，部分依赖于 NOD1/2 激活，导致胃肠炎。作为一种生存机制，鼠伤寒杆菌已经适应了这些情况。考虑到 ER 应激在肠道炎症中的重要性以及 S.Tm 是胃肠炎的主要原因这一事实，ER 应激令人惊讶。此外，目前尚不清楚 S.Tm 是否可以利用 ER 应激诱导的炎症导致管腔扩张。我们的中心假设是胃肠道中 ER 应激反应的激活对 S.Tm 诱发的炎症、管腔扩张和病理学有显着影响。我们将通过追求以下三个目标来检验我们的假设。 1) 确定钙流和 UPR 激活对 NOD1/2 信号传导的贡献在体外实验中，我们将确定 UPR 的哪些分支与钙信号传导失调一起导致 NOD1/2 激活。 2) 确定 CHOP 在 S.Tm 诱导的结肠炎模型中的作用我们将使用 Chop-/- 小鼠和条件突变小鼠研究 CHOP 在 S.Tm 诱导的炎症和生长中的作用。 NOD1/2 和 IRE1α 对 S.Tm 的反应我们将研究 IRE1α 在 S.Tm 诱导的结肠炎模型中的作用。协调 ER 的 UPR 下游应激诱导的反应对于安全地调节这一过程以开发未来的治疗方法是必要的，并将显着增加我们对沙门氏菌发病机制的理解。