Pregnane X receptor (PXR)-activating gut bacterial metabolites

孕烷 X 受体 (PXR) 激活肠道细菌代谢物

基本信息

批准号：
10606538
负责人：
Hyunyoung Jeong
金额：
$ 22.52万
依托单位：
PURDUE UNIVERSITY
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：
2022-04-08 至 2025-03-31
项目状态：
未结题

来源：
https://reporter.nih.gov/project-details/10606538
关键词：
Affect Biological Biological Assay Biological Process CYP3A4 gene Cecum Cells Chemicals Collection Culture Media DNA sequencing Data Disease Drug Regulations Enzymes Follow-Up Studies Fractionation Fusobacterium nucleatum Future Gene Cluster Gene Expression Genes Genetic Determinism Germ-Free Goals Health HepG2 Homeostasis Homologous Gene Human Human body Intestines Investigation Knowledge Libraries Ligands Liver Maintenance Mass Spectrum Analysis Mediating Messenger RNA Methods Microbe Molecular Mus Pharmaceutical Preparations Physiology Production Protons Receptor Activation Receptor Cell Regulation Reporter Reporting Research Resolution Role Structural Genes Structure Transactivation bacterial genetics gut bacteria gut homeostasis gut microbes gut microbiota host-microbe interactions immune function microbial microbial products mutant novel overexpression pregnane X receptor promoter recruit screening small molecule tool transcription factor

项目摘要

The gut microbiota modulates human health and disease often via the production of small molecule metabolites; however, the identities of the majority of gut microbial metabolites and their biological actions remain largely unknown. Pregnane X receptor (PXR) is a ligand-activated transcription factor that is activated by structurally diverse chemicals. PXR regulates the expression of genes encoding drug-metabolizing enzymes including cytochrome P450 3A4 (CYP3A4). Additionally, PXR in the intestine and liver has been implicated in the maintenance of gut barrier and immune functions as well as energy homeostasis. Accumulating evidence suggests that the gut microbiota produces PXR ligands. To date, few bacterial metabolites have been reported as mouse or human PXR ligands, and systematic efforts to identify PXR- activating, gut microbial metabolites have been lacking. This lack of knowledge constitutes a substantial gap in defining how the gut microbiota alters human health and disease especially via PXR. The long-term goal of our research is to identify and characterize factors mediating gut microbes-host interactions. The overall objective of this application is to identify gut bacterial metabolites activating PXR, a ligand-activated transcription factor with pleiotropic biological functions including the regulation of drug-metabolizing enzymes and the maintenance of gut homeostasis. Our central hypothesis is that gut bacteria produce metabolites that activate PXR. Our hypothesis is based on the following preliminary results: (1) In HepG2 cells overexpressing human PXR (HepG2/hPXR), the organic extracts of mouse cecum contents significantly induced hPXR transactivation of PXR target gene (i.e., CYP3A4) promoter, indicating the presence of hPXR activators among gut microbial products. (2) A screening of 10 common human gut bacteria led to identification of Fusobacterium nucleatum as a producer of hPXR activator(s); in HepG2/hPXR cells, the organic extracts of F. nucleatum culture supernatants significantly induced hPXR transactivation of the CYP3A4 promoter. (3) We increased the yield of the active metabolite from F. nucleatum by changing the growth media and obtained a proton NMR and high- resolution mass spectrometry results of an active metabolite-enriched fraction. The results suggest that PXR- activating metabolite(s) of F. nucleatum are likely novel compounds. Together, our data indicate that gut bacteria produce as-yet-unknown metabolite(s) that activate PXR. Based our findings, we propose to (1) identify gut bacteria-derived metabolites that promote hPXR transactivation of CYP3A4 expression and (2) define genetic determinants for the production of hPXR activator(s) in F. nucleatum. Successful completion of these studies will set the stage for future investigation, providing much-needed tool sets to investigate underlying molecular mechanisms for how the gut microbiota modulates PXR activity. Together, these efforts will enhance our understanding of how the gut microbiota controls host physiology.

肠道微生物群通常通过产生小分子来调节人类健康和疾病代谢物；然而，大多数肠道微生物代谢物的特性及其生物学作用仍然很大程度上不为人所知。孕烷 X 受体 (PXR) 是一种配体激活的转录因子，被激活由结构不同的化学物质。 PXR 调节编码药物代谢基因的表达酶包括细胞色素 P450 3A4 (CYP3A4)。此外，肠道和肝脏中的 PXR 已被证实涉及维持肠道屏障和免疫功能以及能量稳态。越来越多的证据表明肠道微生物群产生 PXR 配体。迄今为止，细菌很少代谢物已被报道为小鼠或人类 PXR 配体，并且系统地努力鉴定 PXR- 缺乏活化的肠道微生物代谢物。这种知识的缺乏造成了巨大的差距定义肠道微生物群如何改变人类健康和疾病，特别是通过 PXR。我们的长期目标研究的目的是识别和表征介导肠道微生物与宿主相互作用的因素。总体目标该应用的目的是鉴定激活 PXR（一种配体激活转录因子）的肠道细菌代谢物具有多效性生物学功能，包括药物代谢酶的调节和维持肠道稳态。我们的中心假设是肠道细菌产生的代谢物可以激活 PXR。我们的假设基于以下初步结果：（1）在过表达人类的 HepG2 细胞中 PXR (HepG2/hPXR)，小鼠盲肠内容物的有机提取物显着诱导 hPXR 反式激活 PXR 靶基因（即 CYP3A4）启动子的存在，表明肠道微生物中存在 hPXR 激活剂产品。 (2) 筛选10种人类肠道常见细菌，鉴定出具核梭杆菌作为 hPXR 激活剂的生产商；在 HepG2/hPXR 细胞中，具核梭菌培养物的有机提取物上清液显着诱导 CYP3A4 启动子的 hPXR 反式激活。 (3) 提高产量通过改变生长培养基，从 F. nucleatum 中提取活性代谢物，并获得质子 NMR 和高富含活性代谢物的级分的分辨率质谱结果。结果表明 PXR- F. nucleatum 的激活代谢物可能是新型化合物。总之，我们的数据表明肠道细菌会产生激活 PXR 的未知代谢物。根据我们的发现，我们建议 (1) 鉴定肠道细菌衍生的代谢物，这些代谢物可促进 CYP3A4 表达的 hPXR 反式激活，以及 (2) 定义 F. nucleatum 中 hPXR 激活剂产生的遗传决定因素。顺利完成这些研究将为未来的调查奠定基础，提供急需的调查工具集肠道微生物群如何调节 PXR 活性的潜在分子机制。共同努力，这些努力将增强我们对肠道微生物群如何控制宿主生理机能的理解。