Mechanisms underlying diarrhea and gut inflammation mediated by Enterotoxigenic and Enteropathogenic E. coli

产肠毒素和致病性大肠杆菌介导的腹泻和肠道炎症的机制

• 批准号: 10674072
• 负责人: Sandhya Visweswariah
• 金额: $ 12.16万
• 依托单位: INDIAN INSTITUTE OF SCIENCE
• 依托单位国家: 美国
• 财政年份: 2023
• 资助国家: 美国
• 起止时间: 2023-08-18 至 2027-07-31
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/10674072
• 关键词: Affect; Animals; Antibodies; Autophagocytosis; Bacterial Infections; Binding; Cell Line; Cell Surface Receptors; Cell physiology; Cells; Child; Childhood; Chlorides; Chronic; Citrobacter rodentium; Colon; Communicable Diseases; Cyclic GMP; Cystic Fibrosis Transmembrane Conductance Regulator; Data; Defect; Developing Countries; Diarrhea; Disease Progression; Engineering; Enteral; Enterotoxins; Environment; Epithelial Cells; Escherichia coli Infections; Face; Flow Cytometry; Fluids and Secretions; Functional disorder; Genes; Goals; Growth; Gut associated lymphoid tissue; Immune; In Vitro; India; Infection; Inflammation; Inflammatory; Innate Immune System; Integrins; Interferons; International; Intestines; Ions; Knock-in Mouse; Laboratories; Lymphocyte; Mediating; Molecular; Monitor; Morbidity - disease rate; Mus; Mutation; Oral Administration; Organoids; Outcome; Output; Paneth Cells; Pathogenesis; Pathology; Pathway Analysis; Phenotype; Phosphorylation; Physiology; Pre-Clinical Model; Predisposition; Research; Role; STAT1 gene; Salts; Signal Transduction; Small Intestines; Sodium; Sodium-Hydrogen Antiporter; T-Lymphocyte; Testing; Th1 Cells; Therapeutic; Toxin; Transgenic Mice; Zinc; Zinc Sulfate; burden of illness; cell type; co-infection; diarrheal disease; efficacy evaluation; enteric infection; enteropathogenic Escherichia coli; enterotoxigenic Escherichia coli; enterotoxin receptor; genetic signature; gut inflammation; in vivo; in vivo imaging; in vivo monitoring; inflammatory marker; intestinal epithelium; intraepithelial; mortality risk; mouse model; novel; novel therapeutic intervention; pathogen; pathogenic bacteria; recruit; reduce symptoms; response; targeted treatment; transcriptome sequencing; wasting

PROJECT SUMMARY Diarrheal diseases mediated by infectious enterotoxigenic Escherichia coli (ETEC) that produce heat-stable enterotoxins (ST) are one of the significant causes of morbidity in developing countries, with children below 5 being the most severely affected. Children infected with these strains show moderate-to-severe diarrhea but face the greatest long-term morbidity and increased risk of death. There are currently no directed therapies against stable toxin-mediated diarrhea, but oral administration of zinc salts has proven to be beneficial. The long-term goal of this proposal is to elucidate the mechanisms of how chronic cGMP-driven increases susceptibility to enteric bacterial pathogens. ST binds to the cell surface receptor guanylyl cyclase C (GC-C, encoded by GUCY2C), expressed in all cell types in the gut but not immune cells. We previously described and characterized hyperactivating mutations in the GUCY2C and generated knock-in mice that display elevated intestinal cGMP and diarrhea. Our studies show that these mice display MSD-like phenotypes. Therefore, we hypothesize that these mice could serve as a pre-clinical model to understand the gut environment seen in children with prolonged episodes of ST-mediated diarrhea. These mice show an interferon- driven intestinal gene signature and Paneth cell defects. We propose to pursue the following objectives and questions in this proposal: (1) Elucidate mechanisms by which the Paneth cell dysfunction seen in transgenic mice occurs at the molecular level using engineered cell lines and organoid cultures; (2) study mechanistic aspects of Stat1 induction, and inflammation in transgenic mice; (3) Monitor the recruitment and maturation of the gut-associated lymphoid tissue (GALT) during cGMP-mediated diarrhea characterize and (4) ask whether a prevailing condition of diarrhea induces a more severe response to further infection by enteropathogenic E. coli (EPEC). Oral administration of zinc sulfate is known to shorten diarrheal episodes in affected children. Therefore, we will incorporate zinc administration in animals to attempt to reverse inflammation and other detrimental phenotypes seen in transgenic mice. Collectively, using these transgenic mice to understand infectious secretory diarrhea will not only elucidate the underlying changes that occur in the gut during prolonged secretory diarrhea but also reveal targets for therapy (e.g., zinc) in alleviating symptoms. Furthermore, our studies will identify vulnerabilities that could be targeted to ensure that co-infection with another bacterial pathogen has minimal impact.

项目摘要 由产热稳定性大肠杆菌（ETEC）介导的腹泻病 肠毒素是发展中国家5岁以下儿童发病的重要原因之一 是受影响最严重的。感染这些菌株的儿童表现出中度至重度腹泻， 最大的长期发病率和死亡风险增加。目前还没有针对 稳定的毒素介导的腹泻，但口服锌盐已被证明是有益的。 该提案的长期目标是阐明慢性cGMP驱动的细胞凋亡的机制。 增加对肠道细菌病原体的易感性。ST与细胞表面受体鸟苷酸环化酶C结合 (GC-C由GUCY 2C编码），在肠道中的所有细胞类型中表达，但不在免疫细胞中表达。我们 先前描述和表征的GUCY 2C中的超活化突变和产生的敲入小鼠 显示肠道cGMP升高和腹泻我们的研究表明，这些小鼠表现出类似MSD的 表型因此，我们假设这些小鼠可以作为临床前模型来了解肠道 在ST介导的腹泻长期发作的儿童中观察到的环境。这些小鼠显示干扰素- 驱动肠道基因签名和潘氏细胞缺陷。我们建议实现以下目标， 本文提出的问题：（1）阐明转基因小鼠潘氏细胞功能障碍的机制， 小鼠发生在分子水平上使用工程细胞系和类器官培养物;（2）研究机制 Stat 1诱导和转基因小鼠中的炎症方面;（3）监测 cGMP介导腹泻期间肠相关淋巴组织（GALT）表征和（4）询问是否 腹泻的流行状况诱导对肠致病性E. coli（EPEC）。已知口服硫酸锌可缩短受影响儿童的腹泻发作。 因此，我们将在动物中加入锌给药，以试图逆转炎症和其他疾病。 在转基因小鼠中观察到的有害表型。 总的来说，使用这些转基因小鼠来了解感染性分泌性腹泻不仅 阐明了在长期分泌性腹泻期间肠道发生的潜在变化，但也揭示了靶点 对于治疗（例如，锌）缓解症状。此外，我们的研究将确定可能 有针对性地确保与另一种细菌病原体的共感染具有最小的影响。