A bacterial bile acid metabolite modulates Treg activity through the nuclear hormone receptor NR4A1

Cell Host Microbe. 2021 Sep 8;29(9):1366-1377.e9. doi: 10.1016/j.chom.2021.07.013. Epub 2021 Aug 19.

Abstract

Bile acids act as signaling molecules that regulate immune homeostasis, including the differentiation of CD4+ T cells into distinct T cell subsets. The bile acid metabolite isoallolithocholic acid (isoalloLCA) enhances the differentiation of anti-inflammatory regulatory T cells (Treg cells) by facilitating the formation of a permissive chromatin structure in the promoter region of the transcription factor forkhead box P3 (Foxp3). Here, we identify gut bacteria that synthesize isoalloLCA from 3-oxolithocholic acid and uncover a gene cluster responsible for the conversion in members of the abundant human gut bacterial phylum Bacteroidetes. We also show that the nuclear hormone receptor NR4A1 is required for the effect of isoalloLCA on Treg cells. Moreover, the levels of isoalloLCA and its biosynthetic genes are significantly reduced in patients with inflammatory bowel diseases, suggesting that isoalloLCA and its bacterial producers may play a critical role in maintaining immune homeostasis in humans.

Keywords: T cells; bile acids; human microbiome; inflammatory bowel disease.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Bacteroidetes / metabolism*
  • Bile Acids and Salts / metabolism*
  • Cell Differentiation / physiology
  • Chromatin / metabolism
  • Forkhead Transcription Factors / genetics
  • Humans
  • Inflammatory Bowel Diseases / pathology
  • Multigene Family / genetics
  • Nuclear Receptor Subfamily 4, Group A, Member 1 / metabolism*
  • Phenanthrenes / metabolism*
  • Promoter Regions, Genetic / genetics
  • Signal Transduction / physiology
  • T-Lymphocyte Subsets / cytology
  • T-Lymphocyte Subsets / immunology
  • T-Lymphocytes, Regulatory / cytology
  • T-Lymphocytes, Regulatory / immunology*

Substances

  • Bile Acids and Salts
  • Chromatin
  • FOXP3 protein, human
  • Forkhead Transcription Factors
  • NR4A1 protein, human
  • Nuclear Receptor Subfamily 4, Group A, Member 1
  • Phenanthrenes
  • isoallolithocholic acid