title: Interaction of δ and κ opioid receptors with adenosine A1 receptors mediates cardioprotection by remote ischemic preconditioning.
abstract: Multiple initiatives are underway to harness the clinical benefits of remote ischemic preconditioning (rIPC) based on applying non-invasive, brief, intermittent limb ischemia/reperfusion using an external occluder. However, little is known about how rIPC induces protection in cardiomyocytes, particularly through G-protein coupled receptors. In these studies, we determined the role of opioid and adenosine receptors and their functional interactions in rIPC cardioprotection. In freshly isolated cardiomyocytes subjected to 45-min simulated ischemia followed by 60-min simulated reperfusion, we examined the ability of plasma dialysate (derived from blood obtained from rabbits remotely preconditioned by application of brief cycles of hind limb ischemia/reperfusion, rIPC dialysate) to protect cells against necrosis. rIPC dialysate and selective activation of either δ-opioid receptors or κ-opioid receptors significantly reduced the % of dead cells after simulated ischemia and simulated reperfusion. Inhibition of adenosine A1 receptors, but not adenosine A3 receptors, blocked the protection by rIPC dialysate, δ-opioid receptor and κ-opioid receptor activation. In HEK293 cells expressing either hemagglutinin A-tagged δ-opioid receptors or hemagglutinin A-tagged κ-opioid receptors, selective immunoprecipitation of adenosine A1 receptors pulled down both δ-opioid and κ-opioid receptors. This molecular association of adenosine A1 receptors with δ-opioid and κ-opioid receptors was confirmed by reverse pull-down assays. These findings strongly suggest that rIPC cardioprotection requires the activation of δ-opioid and κ-opioid receptors and relies on these receptors functionally interacting with adenosine A1 receptors.
authors.affiliation: Division of Cell Biology, The Research Institute, The Hospital for Sick Children, Toronto, Ontario, Canada.
authors.forename: Harinee
authors.initials: H
authors.lastname: Surendra
authors.forename: Roberto J
authors.initials: RJ
authors.lastname: Diaz
authors.forename: Kordan
authors.initials: K
authors.lastname: Harvey
authors.forename: Michael
authors.initials: M
authors.lastname: Tropak
authors.forename: John
authors.initials: J
authors.lastname: Callahan
authors.forename: Alina
authors.initials: A
authors.lastname: Hinek
authors.forename: Taneya
authors.initials: T
authors.lastname: Hossain
authors.forename: Andrew
authors.initials: A
authors.lastname: Redington
authors.forename: Gregory J
authors.initials: GJ
authors.lastname: Wilson
mesh_terms: D058916:Adenosine A1 Receptor Antagonists / Q000494:pharmacology; D000818:Animals; D057809:HEK293 Cells; D006801:Humans; D019157:Ischemic Preconditioning, Myocardial; D032383:Myocytes, Cardiac / Q000378:metabolism* / Q000473:pathology; D011817:Rabbits; D043682:Receptor, Adenosine A1 / Q000378:metabolism*; D017465:Receptors, Opioid, delta / Q000378:metabolism*; D017473:Receptors, Opioid, kappa / Q000378:metabolism*
chemical_list: D058916:Adenosine A1 Receptor Antagonists; D043682:Receptor, Adenosine A1; D017465:Receptors, Opioid, delta; D017473:Receptors, Opioid, kappa