PD-1+ melanocortin receptor dependent-Treg cells prevent autoimmune disease

Sci Rep. 2019 Nov 15;9(1):16941. doi: 10.1038/s41598-019-53297-w.

Abstract

Experimental autoimmune uveoretinitis (EAU) is a mouse model of human autoimmune uveitis marked by ocular autoantigen-specific regulatory immunity in the spleen. The melanocortin 5 receptor (MC5r) and adenosine 2 A receptor (A2Ar) are required for induction of post-EAU regulatory T cells (Tregs) which provide resistance to EAU. We show that blocking the PD-1/PD-L1 pathway prevented suppression of EAU by post-EAU Tregs. A2Ar induction of PD-1+FoxP3+ Tregs in uveitis patients was similar compared to healthy controls, but was significantly reduced with melanocortin stimulation. Further, lower body mass index correlated with responsiveness to stimulation of this pathway. These observations indicate an importance of the PD-1/PD-L1 pathway to provide resistance to relapsing uveitis and shows a reduced capacity of uveitis patients to induce Tregs when stimulated through melanocortin receptors, but that it is possible to bypass this part of the pathway through direct stimulation of A2Ar.

Publication types

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

MeSH terms

  • Adult
  • Animals
  • Antigen-Presenting Cells / immunology
  • Antigen-Presenting Cells / metabolism
  • Autoantigens / immunology
  • Autoimmune Diseases / immunology
  • Autoimmune Diseases / metabolism*
  • Autoimmune Diseases / prevention & control*
  • Autoimmunity
  • Biomarkers
  • Cytokines / metabolism
  • Disease Models, Animal
  • Disease Susceptibility
  • Female
  • Humans
  • Immunomodulation
  • Inflammation Mediators / metabolism
  • Male
  • Mice
  • Middle Aged
  • Programmed Cell Death 1 Receptor / metabolism*
  • Receptors, Melanocortin / metabolism*
  • T-Lymphocytes, Regulatory / immunology*
  • T-Lymphocytes, Regulatory / metabolism*
  • Uveitis / etiology
  • Uveitis / metabolism
  • Uveitis / pathology

Substances

  • Autoantigens
  • Biomarkers
  • Cytokines
  • Inflammation Mediators
  • Programmed Cell Death 1 Receptor
  • Receptors, Melanocortin