title: Late preconditioning elicited by activation of adenosine A(3) receptor in heart: role of NF- kappa B, iNOS and mitochondrial K(ATP) channel.
abstract: Activation of adenosine A(3) receptor (A(3)AR) protects against ischemia/reperfusion injury in the heart. However, the downstream signaling mechanisms leading to its delayed anti-ischemic effects remain unclear. We hypothesized that A(3)AR stimulation protects the heart via activation of nuclear transcription factor kappa B (NF-kappa B) and synthesis of inducible nitric oxide synthase (iNOS). Mice were treated with selective A(3)AR agonist, N(6)-(3-iodobenzyl) adenosine-5;-N-methyluronamide (IB-MECA). Twenty-four h later, hearts were perfused in Langendorff mode and subjected to 30 min of global ischemia and 30 min of reperfusion. IB-MECA caused post-ischemic reduction in necrosis and improvement in myocardial performance which was abolished by A(3)AR antagonist, MRS1191. Electrophoretic mobility shift assay demonstrated increased NF-kappa B binding in nuclear extracts following A(3)AR stimulation, which was diminished by MRS1191 and NF-kappa B inhibitor, pyrrolidinediethyldithiocarbamate (PDTC). The cardioprotection was abrogated by PDTC and targeted ablation of p50 subunit of NF-kappa B in mice. The inhibition of iNOS with S-methylisothiourea and targeted disruption of the iNOS gene also abolished the protective effect of A(3)AR stimulation. Expression of iNOS mRNA and NO production were enhanced after 6 and 24 h respectively of IB-MECA treatment. MRS1191 and PDTC blocked IB-MECA induced NO production after A(3)AR stimulation. MitoK(ATP) channel blocker, 5-hydroxydecanoate abolished the protective effect of A(3)AR. For the first time, we have provided direct evidence of an essential role of NF- kappa B activation and iNOS in A(3)AR-induced late preconditioning. Selective activation of A(3)AR with IB-MECA can be used to trigger long-lasting ischemic protection in the heart.
authors.affiliation: Division of Cardiology, Medical College of Virginia, Richmond, VA 23298, USA.
authors.forename: Ting C
authors.initials: TC
authors.lastname: Zhao
authors.forename: Rakesh C
authors.initials: RC
authors.lastname: Kukreja
mesh_terms: D000241:Adenosine / Q000031:analogs & derivatives* / Q000494:pharmacology; D000818:Animals; D024202:Electrophoretic Mobility Shift Assay; D006321:Heart / Q000187:drug effects; D019157:Ischemic Preconditioning, Myocardial; D008297:Male; D051379:Mice; D008813:Mice, Inbred ICR; D008929:Mitochondria, Heart / Q000378:metabolism*; D009206:Myocardium / Q000378:metabolism* / Q000473:pathology; D016328:NF-kappa B / Q000378:metabolism*; D019001:Nitric Oxide Synthase / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism*; D052247:Nitric Oxide Synthase Type II; D015221:Potassium Channels / Q000378:metabolism*; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D043684:Receptor, Adenosine A3; D018047:Receptors, Purinergic P1 / Q000378:metabolism*; D015427:Reperfusion Injury / Q000378:metabolism / Q000517:prevention & control; D020133:Reverse Transcriptase Polymerase Chain Reaction
chemical_list: D016328:NF-kappa B; D015221:Potassium Channels; D012333:RNA, Messenger; D043684:Receptor, Adenosine A3; D018047:Receptors, Purinergic P1; C084956:N(6)-(3-iodobenzyl)-5'-N-methylcarboxamidoadenosine; D019001:Nitric Oxide Synthase; D052247:Nitric Oxide Synthase Type II; C496317:Nos2 protein, mouse; D000241:Adenosine