title: A2A adenosine receptor induction inhibits IFN-gamma production in murine CD4+ T cells.
abstract: Incubation of purified C57BL/6 murine CD4(+) T lymphocytes with anti-CD3 mAb serves as a model of TCR-mediated activation and results in increased IFN-gamma production and cell surface expression of CD25 and CD69. We demonstrate here that signaling through the TCR causes a rapid (4-h) 5-fold increase in A(2A) adenosine receptor (AR) mRNA, which is correlated with a significant increase in the efficacy of A(2A)AR-mediated cAMP accumulation in these cells. A(2A)AR activation reduces TCR-mediated production of IFN-gamma by 98% with a potency order of 4-{3-[6-amino-9-(5-ethylcarbamoyl-3,4-dihydroxytetrahydrofuran-2-yl)-9H-purin-2-yl]prop-2-ynyl}cyclohexanecarboxylic acid methyl ester (ATL146e; EC(50) = 0.19 +/- 0.03 nM) > 4-{3-[6-amino-9-(5-cyclopropyl-carbamoyl-3,4-dihydroxytetrahydrofuran-2-yl)-9H-purin-2-yl]prop-2-ynyl}piperidine-1-carboxylic acid methyl ester (ATL313; 0.43 +/- 0.06 nM) > 5'-N-ethylcarboxamidoadenosine (3.5 +/- 0.77 nM) > 2-[4-(2-carboxyethyl)phenethylamino]-5'-N-ethylcarboxamidoadenosine (CGS21680; 7.2 +/- 1.4 nM) >> N(6)-cyclohexyladenosine (110 +/- 33 nM) > 2-chloro-N(6)-(3-iodobenzyl)-5'-N-methylcarboxamide (390 +/- 160 nM), similar to the potency order to compete for radioligand binding to the recombinant murine A(2A)AR but not the A(3)AR. The selective A(2A)AR antagonist, 4-(2-[7-amino-2-[2-furyl][1,2,4]triazolo[2,3-a][1,3,5]triazin-5-yl-amino]ethyl)phenol (ZM241385), inhibits the effect of ATL146e with a pA(2) of 0.34 nM and also inhibits the effects of N(6)-cyclohexyl-adenosine and 2-chloro-N(6)-(3-iodobenzyl)-5'-N-methylcarboxamide. In CD4(+) T cells derived from A(2A)AR(-/-) and A(2A)AR(+/-) mice, the IFN-gamma release response to ATL146e is reduced by 100 and 50%, respectively, indicative of a gene dose effect. The response of T cells to the phosphodiesterase inhibitor, 4-(3'-cyclopentyloxy-4'-methoxyphenyl)-2-pyrrolidone (rolipram), is not affected by A(2A)AR deletion. We conclude that the rapid induction of the A(2A)AR mRNA in T cells provides a mechanism for limiting T cell activation and secondary macrophage activation in inflamed tissues.
authors.affiliation: Department of Pharmacology, University of Virginia, Charlottesville, VA 22908, USA. cl9m@virginia.edu
authors.forename: Courtney M
authors.initials: CM
authors.lastname: Lappas
authors.forename: Jayson M
authors.initials: JM
authors.lastname: Rieger
authors.forename: Joel
authors.initials: J
authors.lastname: Linden
mesh_terms: D000241:Adenosine / Q000031:analogs & derivatives / Q000378:metabolism / Q000494:pharmacology; D058908:Adenosine A2 Receptor Agonists; D058917:Adenosine A2 Receptor Antagonists; D000818:Animals; D015496:CD4-Positive T-Lymphocytes / Q000276:immunology* / Q000378:metabolism*; D002460:Cell Line; D000242:Cyclic AMP / Q000096:biosynthesis; D003509:Cyclohexanecarboxylic Acids / Q000037:antagonists & inhibitors / Q000494:pharmacology; D018628:Gene Dosage; D006801:Humans; D007371:Interferon-gamma / Q000037:antagonists & inhibitors* / Q000096:biosynthesis*; D008213:Lymphocyte Activation / Q000235:genetics / Q000276:immunology; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D018345:Mice, Knockout; D011687:Purines / Q000037:antagonists & inhibitors / Q000494:pharmacology; D012333:RNA, Messenger / Q000096:biosynthesis; D043705:Receptor, Adenosine A2A / Q000096:biosynthesis* / Q000172:deficiency; D011948:Receptors, Antigen, T-Cell / Q000037:antagonists & inhibitors / Q000502:physiology; D020889:Rolipram / Q000494:pharmacology; D014227:Triazines / Q000494:pharmacology; D014230:Triazoles / Q000494:pharmacology
chemical_list: C431129:ATL 146e; D058908:Adenosine A2 Receptor Agonists; D058917:Adenosine A2 Receptor Antagonists; D003509:Cyclohexanecarboxylic Acids; D011687:Purines; D012333:RNA, Messenger; D043705:Receptor, Adenosine A2A; D011948:Receptors, Antigen, T-Cell; D014227:Triazines; D014230:Triazoles; C097270:ZM 241385; D007371:Interferon-gamma; D000242:Cyclic AMP; D020889:Rolipram; D000241:Adenosine