title: cGMP-mediated inhibition of TNF-alpha production by the atrial natriuretic peptide in murine macrophages.
abstract: The atrial natriuretic peptide (ANP) is suggested to regulate inflammatory response by alteration of macrophage functions. The aim of this study was to investigate whether ANP influences production of TNF-alpha. TNF-alpha production in murine bone marrow-derived macrophages was induced by LPS, and TNF-alpha secretion (+/-ANP) was determined by L929 bioassay. ANP dose dependently (10-8-10-6 M) inhibited TNF-alpha release by up to 95%. The effect was mediated via the guanylate cyclase-coupled A receptor, as was shown by employing dibutyryl-cGMP, the cGMP-inhibitory compound Ly-83583, and the A receptor antagonist HS-142-1. A specific ligand of the natriuretic peptide "clearance" receptor inhibited TNF-alpha production only at 10-7 and 10-8 M, but not at 10-6 M. The B receptor ligand C-type natriuretic peptide showed no TNF-alpha-inhibitory effect. To investigate the underlying mechanism of ANP-mediated TNF-alpha inhibition, Northern blot was performed. ANP-treated macrophages displayed decreased TNF-alpha-mRNA levels. Besides the known inhibition of NF-kappaB activation, in this study we demonstrated that ANP also attenuates the activation of the proinflammatory transcription factor AP-1 (gel shift assay). ANP did not alter subunit composition of AP-1 complexes, as was shown by supershift assays applying anti-c-jun and anti-c-fos Abs. To get information on the ANP effect for human inflammatory processes, we investigated cytokine production in human LPS-activated blood. ANP significantly attenuated production of TNF-alpha and IL-1beta without affecting production of IL-10 and IL-1ra. In summary, ANP was shown to attenuate TNF-alpha production of LPS-activated macrophages via cGMP. The inhibition is suggested to involve transcriptional processes that are the result of reduced activation of responsible transcription factors.
authors.affiliation: Institute of Pharmacy, Center of Drug Research, Pharmaceutical Biology, University of Munich, Germany. Alexandra.Kiemer@cup.uni-muenchen.de
authors.forename: A K
authors.initials: AK
authors.lastname: Kiemer
authors.forename: T
authors.initials: T
authors.lastname: Hartung
authors.forename: A M
authors.initials: AM
authors.lastname: Vollmar
mesh_terms: D000818:Animals; D009320:Atrial Natriuretic Factor / Q000037:antagonists & inhibitors* / Q000494:pharmacology / Q000502:physiology*; D001854:Bone Marrow Cells / Q000276:immunology / Q000378:metabolism; D002478:Cells, Cultured; D006152:Cyclic GMP / Q000502:physiology*; D016207:Cytokines / Q000037:antagonists & inhibitors / Q000096:biosynthesis / Q000097:blood; D004268:DNA-Binding Proteins / Q000378:metabolism; D006801:Humans; D007166:Immunosuppressive Agents / Q000494:pharmacology; D046911:Macromolecular Substances; D008264:Macrophages / Q000276:immunology* / Q000378:metabolism*; D051379:Mice; D020098:Natriuretic Peptide, C-Type / Q000494:pharmacology; D012333:RNA, Messenger / Q000037:antagonists & inhibitors / Q000378:metabolism; D017461:Receptors, Atrial Natriuretic Factor / Q000502:physiology; D018808:Transcription Factor AP-1 / Q000037:antagonists & inhibitors / Q000378:metabolism; D014409:Tumor Necrosis Factor-alpha / Q000037:antagonists & inhibitors* / Q000096:biosynthesis* / Q000235:genetics
chemical_list: D016207:Cytokines; D004268:DNA-Binding Proteins; D007166:Immunosuppressive Agents; D046911:Macromolecular Substances; D012333:RNA, Messenger; D018808:Transcription Factor AP-1; D014409:Tumor Necrosis Factor-alpha; D020098:Natriuretic Peptide, C-Type; D009320:Atrial Natriuretic Factor; D017461:Receptors, Atrial Natriuretic Factor; D006152:Cyclic GMP