title: A2A adenosine receptors and C/EBPbeta are crucially required for IL-10 production by macrophages exposed to Escherichia coli.
abstract: We recently showed that A(2A) adenosine receptor activation by endogenous adenosine contributes to interleukin-10 (IL-10) production in polymicrobial sepsis. Here we investigated the molecular mechanisms underpinning this interaction between adenosine receptor signaling and infection by exposing macrophages to Escherichia coli. We demonstrated using receptor knockout mice that A(2A) receptor activation is critically required for the stimulatory effect of adenosine on IL-10 production by E coli-challenged macrophages, whereas A(2B) receptors have a minor role. The stimulatory effect of adenosine on E coli-induced IL-10 production did not require toll-like receptor 4 (TLR4) or MyD88, but was blocked by p38 inhibition. Using shRNA we demonstrated that TRAF6 impairs the potentiating effect of adenosine. Measuring IL-10 mRNA abundance and transfection with an IL-10 promoter-luciferase construct indicated that E coli and adenosine synergistically activate IL-10 transcription. Sequential deletion analysis and site-directed mutagenesis of the IL-10 promoter revealed that a region harboring C/EBP binding elements was responsible for the stimulatory effect of adenosine on E coli-induced IL-10 promoter activity. Adenosine augmented E coli-induced nuclear accumulation and DNA binding of C/EBPbeta. C/EBPbeta-deficient macrophages failed to produce IL-10 in response to adenosine and E coli. Our results suggest that the A(2A) receptor-C/EBPbeta axis is critical for IL-10 production after bacterial infection.
authors.affiliation: Department of Surgery, University of Medicine and Dentistry of New Jersey, New Jersey Medical School, Newark, NJ 07103, USA.
authors.forename: Balázs
authors.initials: B
authors.lastname: Csóka
authors.forename: Zoltán H
authors.initials: ZH
authors.lastname: Németh
authors.forename: László
authors.initials: L
authors.lastname: Virág
authors.forename: Pál
authors.initials: P
authors.lastname: Gergely
authors.forename: S Joseph
authors.initials: SJ
authors.lastname: Leibovich
authors.forename: Pál
authors.initials: P
authors.lastname: Pacher
authors.forename: Chun-Xiao
authors.initials: CX
authors.lastname: Sun
authors.forename: Michael R
authors.initials: MR
authors.lastname: Blackburn
authors.forename: E Sylvester
authors.initials: ES
authors.lastname: Vizi
authors.forename: Edwin A
authors.initials: EA
authors.lastname: Deitch
authors.forename: György
authors.initials: G
authors.lastname: Haskó
mesh_terms: D024506:5' Flanking Region / Q000235:genetics; D000241:Adenosine / Q000494:pharmacology; D000818:Animals; D022782:CCAAT-Enhancer-Binding Protein-beta / Q000235:genetics / Q000378:metabolism*; D002478:Cells, Cultured; D004789:Enzyme Activation; D004926:Escherichia coli / Q000502:physiology*; D016753:Interleukin-10 / Q000096:biosynthesis* / Q000235:genetics / Q000378:metabolism; D008264:Macrophages / Q000187:drug effects / Q000378:metabolism*; D008297:Male; D051379:Mice; D053594:Myeloid Differentiation Factor 88 / Q000378:metabolism; D011401:Promoter Regions, Genetic / Q000235:genetics; D012333:RNA, Messenger / Q000235:genetics; D043705:Receptor, Adenosine A2A / Q000378:metabolism*; D048029:TNF Receptor-Associated Factor 6 / Q000378:metabolism; D051197:Toll-Like Receptor 4 / Q000378:metabolism; D048051:p38 Mitogen-Activated Protein Kinases / Q000378:metabolism
chemical_list: D022782:CCAAT-Enhancer-Binding Protein-beta; D053594:Myeloid Differentiation Factor 88; D012333:RNA, Messenger; D043705:Receptor, Adenosine A2A; D048029:TNF Receptor-Associated Factor 6; C493487:Tlr4 protein, mouse; D051197:Toll-Like Receptor 4; D016753:Interleukin-10; D048051:p38 Mitogen-Activated Protein Kinases; D000241:Adenosine