title: Mu opioid receptor stimulation activates c-Jun N-terminal kinase 2 by distinct arrestin-dependent and independent mechanisms.
abstract: G protein-coupled receptor desensitization is typically mediated by receptor phosphorylation by G protein-coupled receptor kinase (GRK) and subsequent arrestin binding; morphine, however, was previously found to activate a c-Jun N-terminal kinase (JNK)-dependent, GRK/arrestin-independent pathway to produce mu opioid receptor (MOR) inactivation in spinally-mediated, acute anti-nociceptive responses [Melief et al.] [1]. In the current study, we determined that JNK2 was also required for centrally-mediated analgesic tolerance to morphine using the hotplate assay. We compared JNK activation by morphine and fentanyl in JNK1(-/-), JNK2(-/-), JNK3(-/-), and GRK3(-/-) mice and found that both compounds specifically activate JNK2 in vivo; however, fentanyl activation of JNK2 was GRK3-dependent, whereas morphine activation of JNK2 was GRK3-independent. In MOR-GFP expressing HEK293 cells, treatment with either arrestin siRNA, the Src family kinase inhibitor PP2, or the protein kinase C (PKC) inhibitor Gö6976 indicated that morphine activated JNK2 through an arrestin-independent Src- and PKC-dependent mechanism, whereas fentanyl activated JNK2 through a Src-GRK3/arrestin-2-dependent and PKC-independent mechanism. This study resolves distinct ligand-directed mechanisms of JNK activation by mu opioid agonists and understanding ligand-directed signaling at MOR may improve opioid therapeutics.
authors.affiliation: Department of Pharmacology, University of Washington, Seattle, WA 98195, USA.
authors.forename: Jamie Rose
authors.initials: JR
authors.lastname: Kuhar
authors.affiliation: Department of Pharmacology, University of Washington, Seattle, WA 98195, USA; Department of Pharmacy and Biotechnology (FaBiT), University of Bologna, Irnerio, 48-40126 Bologna, Italy.
authors.forename: Andrea
authors.initials: A
authors.lastname: Bedini
authors.affiliation: Department of Pharmacology, University of Washington, Seattle, WA 98195, USA; Department of Pathology, University of Washington, Seattle, WA 98195, USA.
authors.forename: Erica J
authors.initials: EJ
authors.lastname: Melief
authors.affiliation: Department of Pharmacology, University of Washington, Seattle, WA 98195, USA.
authors.forename: Yen-Chen
authors.initials: YC
authors.lastname: Chiu
authors.affiliation: Department of Pharmacology, University of Washington, Seattle, WA 98195, USA.
authors.forename: Heather N
authors.initials: HN
authors.lastname: Striegel
authors.affiliation: Department of Pharmacology, University of Washington, Seattle, WA 98195, USA. Electronic address: cchavkin@u.washington.edu.
authors.forename: Charles
authors.initials: C
authors.lastname: Chavkin
mesh_terms: D000818:Animals; D019393:Arrestin / Q000235:genetics / Q000378:metabolism*; D002227:Carbazoles / Q000494:pharmacology; D004789:Enzyme Activation / Q000187:drug effects; D005283:Fentanyl / Q000494:pharmacology*; D054770:G-Protein-Coupled Receptor Kinase 3 / Q000235:genetics / Q000378:metabolism; D057809:HEK293 Cells; D006801:Humans; D051379:Mice; D018345:Mice, Knockout; D048056:Mitogen-Activated Protein Kinase 9 / Q000235:genetics / Q000378:metabolism*; D009020:Morphine / Q000494:pharmacology*; D011493:Protein Kinase C / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism; D017450:Receptors, Opioid, mu / Q000235:genetics / Q000378:metabolism*; D019061:src-Family Kinases / Q000235:genetics / Q000378:metabolism
chemical_list: D019393:Arrestin; D002227:Carbazoles; D017450:Receptors, Opioid, mu; C081021:Go 6976; D009020:Morphine; D048056:Mitogen-Activated Protein Kinase 9; D019061:src-Family Kinases; D011493:Protein Kinase C; D054770:G-Protein-Coupled Receptor Kinase 3; C517850:GRK3 protein, mouse; D005283:Fentanyl
keywords: Arrestin; Fentanyl; JNK; Morphine; Opioid; Tolerance