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Am J Physiol Gastrointest Liver Physiol. 2014 Aug 1;307(3):G338-46. doi: 10.1152/ajpgi.00404.2013. Epub 2014 May 29.

Extracellular adenosine regulates colitis through effects on lymphoid and nonlymphoid cells.

Author information

1
Digestive Health Center of Excellence, University of Virginia, Charlottesville, Virginia;
2
Center for Veterinary Sciences and Comparative Medicine, University of California, San Diego, La Jolla, California; Division of Comparative Pathology and Medicine, Department of Pathology, University of California, San Diego, La Jolla, California;
3
Center for Comparative Medicine, University of Virginia, Charlottesville, Virginia;
4
Infectious and Inflammatory Disease Center, Sanford-Burnham Medical Research Institute, La Jolla, California; and.
5
La Jolla Institute for Allergy and Immunology, La Jolla, California.
6
Center for Veterinary Sciences and Comparative Medicine, University of California, San Diego, La Jolla, California; Division of Comparative Pathology and Medicine, Department of Pathology, University of California, San Diego, La Jolla, California; pernst@ucsd.edu.

Abstract

Adenosine is a purine metabolite that can mediate anti-inflammatory responses in the digestive tract through the A(2A) adenosine receptor (A(2A)AR). We examined the role of this receptor in the control of inflammation in the adoptive transfer model of colitis. Infection of A(2A)AR(-/-) mice with Helicobacter hepaticus increased colonic inflammation scores compared with uninfected A(2A)AR controls. Comparison of T cell subsets in wild-type and A(2A)AR(-/-) mice revealed differences in markers associated with activated helper T (Th) cells and regulatory T (Treg) cells. Previous studies showed that expression of A(2A)AR on CD45RB(HI) and CD45RB(LO) Th cells is essential for the proper regulation of colonic inflammation. Adoptive transfer of CD45RB(HI) with CD45RB(LO) from wild-type mice into RAG1(-/-)/A(2A)AR(-/-) mice induced severe disease within 3 wk, although transfer of the same subsets into RAG1(-/-) mice does not induce colitis. This suggests that the presence of A(2A)AR on recipient cells is also important for controlling colitis. To investigate the role of A(2A)AR in myeloid cells, chimeric recipients were generated by injection of bone marrow from RAG1(-/-) or RAG1(-/-)/A(2A)AR(-/-) mice into irradiated RAG1(-/-) mice. After adoptive transfer, these recipients did not develop colitis, regardless of A(2A)AR expression by the donor. Together, our results suggest that the control of inflammation in vivo is dependent on A(2A)AR signaling through multiple cell types that collaborate in the regulation of colitis by responding to extracellular adenosine.

KEYWORDS:

A2A adenosine receptor; adenosine; adoptive transfer; colitis; regulatory T cells

PMID:
24875104
PMCID:
PMC4121634
DOI:
10.1152/ajpgi.00404.2013
[Indexed for MEDLINE]
Free PMC Article

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