The therapeutic potential of gut microbiota-derived metabolite 4-phenylbutyric acid in Escherichia coli (E.coli)-induced colitis

Escherichia coli (E. coli) is a widely distributed highly infectious pathogen that can cause varying degrees of zoonotic diseases, harm farm livestock, and result in economic losses. It has a wide range of transmission routes and mainly harms the intestines of animals, causing intestinal inflammation and damage. Due to genetic characteristics and excessive use of antibiotics, many drug-resistant strains have emerged. According to reports, the internal environment of gut microbiota can regulate the occurrence and development of various diseases, and probiotics can effectively protect gut health and enhance resistance to the outside world. The mechanism by which gut microbiota and its metabolites regulate E. coli infection is still limited. Our scientific hypothesis is based on the close relationship between intestinal damage and dysbiosis caused by E. coli infection and uninfected gut and microbiota. The aim of this project is to use a multi omics approach combining 16S rRNA sequencing and metabolomics to analyze and identify key gut microbiota and metabolites that affect the process of E. coli infection, and further elucidate the mechanism by which gut microbiota and their metabolites regulate intestinal inflammation caused by E. coli infection through the TLR4/MyD88/NF - κ B pathway. This will provide important guidance for the development of drugs for the treatment of E. coli disease.

The samples for this experiment are calf feces, including the diarrhea group and the healthy group (without obvious diarrhea), with 6 samples in each group. The samples was sourced from a large-scale dairy farm in Yunnan, China, and the sampling subjects were newborn cows aged 3-6 months. The collection method is as follows: after wearing personal protective equipment, use fully disinfected and cleaned tools (gloves, shovels, spoons, straws) to collect samples from fresh feces center, place them in a clean and sealed container, record the sampling date, time, calf number and other information, and record relevant data. After sampling, divide and store in the refrigerator for refrigeration.

大肠杆菌（Escherichia coli, E. coli）是一种分布广泛的高致病性病原微生物，可引发不同程度的人畜共患病，危害畜禽养殖产业并造成经济损失。该菌传播途径多样，主要侵害动物肠道，引发肠道炎症与组织损伤。受自身遗传特性与抗生素过度使用的影响，目前已涌现出众多耐药菌株。据研究显示，肠道菌群（gut microbiota）的内部微环境可调控多种疾病的发生与发展，而益生菌能够有效维护肠道健康、增强机体对外界的抵抗力。当前关于肠道菌群及其代谢产物调控大肠杆菌感染的分子机制仍较为匮乏。本研究的科学假说基于大肠杆菌感染引发的肠道损伤与菌群失调，以及未感染状态下肠道与菌群的紧密关联。本项目旨在采用结合16S rRNA测序与代谢组学的多组学（multi omics）研究策略，分析并筛选影响大肠杆菌感染进程的关键肠道菌群与代谢产物，进一步阐明肠道菌群及其代谢产物通过TLR4/MyD88/NF-κB通路调控大肠杆菌感染所致肠道炎症的分子机制，这将为防治大肠杆菌病的药物研发提供重要的理论指导。

本实验的样本为犊牛粪便，分为腹泻组与健康组（无明显腹泻症状），每组各6份样本。样本采集自中国云南某大型奶牛场，采样对象为3~6月龄的犊牛。样本采集流程如下：穿戴个人防护装备后，使用经彻底消毒清洁的工具（手套、铲子、勺子、吸管）采集新鲜粪便的中心部位样本，置于洁净密封的容器中，记录采样日期、时间、犊牛编号等相关信息并归档实验数据。采样完成后，将样本分装并置于冰箱冷藏保存。