pH sensing controls tissue inflammation by modulating cellular metabolism and endo-lysosomal function of immune cells

Nat Immunol. 2022 Jul;23(7):1063-1075. doi: 10.1038/s41590-022-01231-0. Epub 2022 Jun 6.

Abstract

Extracellular acidification occurs in inflamed tissue and the tumor microenvironment; however, a systematic study on how pH sensing contributes to tissue homeostasis is lacking. In the present study, we examine cell type-specific roles of the pH sensor G protein-coupled receptor 65 (GPR65) and its inflammatory disease-associated Ile231Leu-coding variant in inflammation control. GPR65 Ile231Leu knock-in mice are highly susceptible to both bacterial infection-induced and T cell-driven colitis. Mechanistically, GPR65 Ile231Leu elicits a cytokine imbalance through impaired helper type 17 T cell (TH17 cell) and TH22 cell differentiation and interleukin (IL)-22 production in association with altered cellular metabolism controlled through the cAMP-CREB-DGAT1 axis. In dendritic cells, GPR65 Ile231Leu elevates IL-12 and IL-23 release at acidic pH and alters endo-lysosomal fusion and degradation capacity, resulting in enhanced antigen presentation. The present study highlights GPR65 Ile231Leu as a multistep risk factor in intestinal inflammation and illuminates a mechanism by which pH sensing controls inflammatory circuits and tissue homeostasis.

Publication types

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

MeSH terms

  • Animals
  • Colitis* / metabolism
  • Hydrogen-Ion Concentration
  • Inflammation / metabolism
  • Lysosomes / metabolism
  • Mice
  • Receptors, G-Protein-Coupled* / genetics
  • Receptors, G-Protein-Coupled* / metabolism
  • Th17 Cells / metabolism

Substances

  • Receptors, G-Protein-Coupled