Pregnane X receptor (PXR)-activating gut bacterial metabolites

孕烷 X 受体 (PXR) 激活肠道细菌代谢物

• 批准号: 10452237
• 负责人: Hyunyoung Jeong
• 金额: $ 20.02万
• 依托单位: PURDUE UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2022
• 资助国家: 美国
• 起止时间: 2022-04-08 至 2024-03-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/10452237
• 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; Regulation; Reporter; Reporting; Research; Resolution; Role; Structural Genes; Structure; Transactivation; bacterial genetics; base; gut bacteria; gut homeostasis; gut microbes; gut microbiota; host-microbe interactions; immune function; microbial; mutant; novel; overexpression; pregnane X receptor; promoter; recruit; screening; small molecule; tool; transcription factor

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身份及其生物学作用 但基本上仍不为人所知。孕烷X受体（PXR）是一种配体激活的转录因子， 结构多样的化学物质。PXR调节药物代谢基因的表达 酶包括细胞色素P450 3A 4（CYP 3A 4）。此外，肠道和肝脏中的PXR已经被 参与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，很少有细菌 代谢物已被报道为小鼠或人PXR配体，并且系统地努力鉴定PXR- 缺乏激活的肠道微生物代谢物。这种知识的缺乏构成了一个巨大的差距， 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。我们的长期目标是 研究的目的是确定和表征介导肠道微生物-宿主相互作用的因素。总体目标 本申请的目的是鉴定激活PXR的肠道细菌代谢物，PXR是一种配体激活的转录因子， 具有多种生物学功能，包括调节药物代谢酶和 维持肠道内稳态。我们的中心假设是肠道细菌产生代谢物， PXR。我们的假设是基于以下初步结果：（1）在HepG 2细胞中， 小鼠盲肠内容物的有机提取物PXR（HepG 2/hPXR）显著诱导hPXR的反式激活 PXR靶基因（即，CYP 3A 4）启动子，表明肠道微生物中存在hPXR激活剂 产品. (2)10种常见人体肠道细菌的筛选及具核梭杆菌的鉴定 在HepG 2/hPXR细胞中，F.核质培养 上清液显著诱导CYP 3A 4启动子的hPXR反式激活。(3)我们提高了 F. nucleatum通过改变生长介质，并获得了质子NMR和高- 活性代谢物富集级分的分辨率质谱结果。结果表明，PXR- F的活化代谢物。nucleatum可能是新的化合物。总之，我们的数据表明， 细菌产生激活PXR的未知代谢物。根据我们的研究结果，我们建议（1） 鉴定促进CYP 3A 4表达的hPXR反式激活的肠道细菌衍生的代谢物，和（2） 确定在F中产生hPXR激活剂的遗传决定因素。具核的成功完成 这些研究将为未来的研究奠定基础，提供急需的研究工具 肠道微生物群如何调节PXR活性的潜在分子机制。总之，这些努力 将增强我们对肠道微生物群如何控制宿主生理的理解。