title: Adenosine kinase inhibitor attenuates the expression of inducible nitric oxide synthase in glial cells.
abstract: The present study demonstrates the anti-inflammatory effect of adenosine kinase inhibitor (ADKI) in glial cells. Treatment of glial cells with IC51, an ADKI, stimulated the extracellular adenosine release and reduced the LPS/IFNgamma-mediated production of NO, and induction of iNOS and TNF-alpha gene expression. The recovery of IC51-mediated inhibition of iNOS expression by adenosine transport inhibitor, S-(4-nitrobenzyl)-6-thioinosine (NBTI), and the inhibition of LPS/IFNgamma-induced iNOS gene expression by exogenous adenosine indicate a role for adenosine release in IC51-mediated iNOS expression. The rescue of IC51-mediated inhibition of iNOS expression by adenosine receptor antagonist for A2A, 8-(3-chlorostyryl)caffeine (CSC) and alloxazine for A2B, further supports a role for interaction of adenosine and its receptors in anti-inflammatory activity. The IC51-mediated induction of cAMP levels, downstream target of A2A and A2B, and inhibition of LPS/IFNgamma-induced expression of iNOS by forskolin, a cAMP activator, document a role for cAMP mediated pathway in anti-inflammatory activity of IC51. Taken together, these studies document that IC51-mediated inhibition of iNOS expression is through activation of adenosine receptors, which activates A2A and A2B resulting in increased cAMP levels following LPS/IFNgamma stimulation. Moreover, the lack of effect of IC51 or adenosine on NFkappaB DNA binding activity and its transactivity indicates that the inhibition of iNOS expression mediated by IC51 may be through an NFkappaB independent pathway.
authors.affiliation: Department of Pediatrics, Medical University of South Carolina, 96 Jonathan Lucas Street, 316 Clinical Science Building, Charleston, SC 29425, USA.
authors.forename: Jin-Koo
authors.initials: JK
authors.lastname: Lee
authors.forename: Je-Seong
authors.initials: JS
authors.lastname: Won
authors.forename: Avtar K
authors.initials: AK
authors.lastname: Singh
authors.forename: Inderjit
authors.initials: I
authors.lastname: Singh
mesh_terms: D000241:Adenosine / Q000378:metabolism; D000248:Adenosine Kinase / Q000037:antagonists & inhibitors*; D000704:Analysis of Variance; D000818:Animals; D015152:Blotting, Northern / Q000379:methods; D015153:Blotting, Western / Q000379:methods; D045744:Cell Line, Tumor; D000242:Cyclic AMP / Q000378:metabolism; D004305:Dose-Response Relationship, Drug; D024202:Electrophoretic Mobility Shift Assay / Q000379:methods; D004797:Enzyme-Linked Immunosorbent Assay / Q000379:methods; D015971:Gene Expression Regulation, Enzymologic / Q000187:drug effects*; D005910:Glioma; D007371:Interferon-gamma / Q000494:pharmacology; D007770:L-Lactate Dehydrogenase / Q000378:metabolism; D007976:Leupeptins / Q000378:metabolism; D008070:Lipopolysaccharides / Q000494:pharmacology; D009457:Neuroglia / Q000187:drug effects* / Q000378:metabolism; D009569:Nitric Oxide / Q000378:metabolism; D019001:Nitric Oxide Synthase / Q000235:genetics / Q000378:metabolism*; D052247:Nitric Oxide Synthase Type II; D011392:Proline / Q000031:analogs & derivatives* / Q000494:pharmacology; D047428:Protein Kinase Inhibitors / Q000494:pharmacology*; D017346:Protein Serine-Threonine Kinases / Q000037:antagonists & inhibitors / Q000378:metabolism; D051381:Rats; D013859:Thiocarbamates / Q000494:pharmacology; D014162:Transfection / Q000379:methods; D014409:Tumor Necrosis Factor-alpha / Q000378:metabolism; D000097782:NF-kappaB-Inducing Kinase
chemical_list: D000241:Adenosine; D000248:Adenosine Kinase; D000242:Cyclic AMP; D007371:Interferon-gamma; D007770:L-Lactate Dehydrogenase; D007976:Leupeptins; D008070:Lipopolysaccharides; D009569:Nitric Oxide; D019001:Nitric Oxide Synthase; D052247:Nitric Oxide Synthase Type II; D011392:Proline; D047428:Protein Kinase Inhibitors; D017346:Protein Serine-Threonine Kinases; D013859:Thiocarbamates; D014409:Tumor Necrosis Factor-alpha; D000097782:NF-kappaB-Inducing Kinase; C066229:prolinedithiocarbamate; C496318:Nos2 protein, rat; C072553:benzyloxycarbonylleucyl-leucyl-leucine aldehyde