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A Role for the Low-Affinity A2B Adenosine Receptor in Regulating Superoxide Generation by Murine Neutrophils
Journal article   Peer reviewed

A Role for the Low-Affinity A2B Adenosine Receptor in Regulating Superoxide Generation by Murine Neutrophils

Dharini van der Hoeven, Tina C. Wan, Elizabeth T. Gizewski, Laura M. Kreckler, Jason E. Maas, Jordan Van Orman, Katya Ravid and John A. Auchampach
The Journal of pharmacology and experimental therapeutics, Vol.338(3), pp.1004-1012
09/01/2011
DOI: 10.1124/jpet.111.181792
PMID: 21693629
url
https://doi.org/10.1124/jpet.111.181792View
Published (Version of record) Open Access

Abstract

The formation of adenosine dampens inflammation by inhibiting most cells of the immune system. Among its actions on neutrophils, adenosine suppresses superoxide generation and regulates chemotactic activity. To date, most evidence implicates the G(s) protein-coupled A(2A) adenosine receptor (AR) as the primary AR subtype responsible for mediating the actions of adenosine on neutrophils by stimulating cAMP production. Given that the A(2B)AR is now known to be expressed in neutrophils and that it is a G(s) protein-coupled receptor, we examined in this study whether it signals to suppress neutrophil activities by using 2[6-amino-3,5-dicyano-4[4-(cyclopropylmethoxy) phenyl]pyridin-2-ylsulfanyl]acetamide (BAY 60-6583), a new agonist for the human A(2B)AR that was confirmed in preliminary studies to be a potent and highly selective agonist for the murine A AR. We found that treating mouse neutrophils with low concentrations (10(-9) and 10(-8) M) of BAY 60-6583 inhibited formylated-methionine-leucine-phenylalanine (fMLP)-stimulated superoxide production by either naive neutrophils, tumor necrosis factor-alpha-primed neutrophils, or neutrophils isolated from mice treated systemically with lipopolysaccharide. This inhibitory action of BAY 60-6583 was confirmed to involve the A(2B)AR in experiments using neutrophils obtained from A(2B)AR gene knockout mice. It is noteworthy that BAY 60-6583 increased fMLP-stimulated superoxide production at higher concentrations (>1 mu M), which was attributed to an AR-independent effect. In a standard Boyden chamber migration assay, BAY 60-6583 alone did not stimulate neutrophil chemotaxis or influence chemotaxis in response to fMLP. These results indicate that the A(2B)AR signals to suppress oxidase activity by murine neutrophils, supporting the idea that this low-affinity receptor for adenosine participates along with the A(2A)AR in regulating the proinflammatory actions of neutrophils.
 Life Sciences & Biomedicine Pharmacology & Pharmacy Science & Technology

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