title: IFN-γ up-regulates κ opioid receptors (KOR) on murine macrophage cell line J774.
abstract: In this study we examined basal and IFN-γ-regulated expression of kappa opioid receptors (KOR) on cells of a murine macrophage cell line, J774. Basal KOR expression was found both at transcriptional and protein levels. KOR protein was predominantly located intracellular (86.4±12.9% positive cells; n=4), and only in minority of J774 cells (9.1±6.4% positive cells; n=4) on plasma membranes, as revealed by Fluorescence-Activated Cell Sorter (FACS) analysis and immunocytochemistry. Proinflammatory cytokine IFN-γ up-regulated KOR expression both at transcriptional (up to 24 times) and protein levels (up to 4.2 times). KOR expressed on J774 cells was functionally active as its ligation with Dynorphin-A(1-17) (100 nM and 1 μM) triggered phosphorylation of ERK1/2. Involvement of KOR in the Dynorphin-A(1-17)-induced triggering of ERK1/2 phosphorylation is suggested since truncated Dynorphin-A(2-17), which does not bind to KOR, was ineffective. Collectively, we have shown for the first time that cells of J774 cell line constitutively express functionally active KOR, which triggers signalization via ERK1/2 phosphorylation and which could be up-regulated by proinflammatory IFN-γ. The data may be relevant for better understanding of the role of KOR and their endogenous ligand Dynorphin-A in regulation of inflammatory and immune responses.
authors.affiliation: Division of Molecular Medicine Laboratory for Experimental Haematology, Immunology and Oncology, "Ruđer Bošković" Institute, Zagreb, Croatia. gabril@irb.hr
authors.forename: Jelka
authors.initials: J
authors.lastname: Gabrilovac
authors.forename: Barbara
authors.initials: B
authors.lastname: Cupić
authors.forename: Emilija
authors.initials: E
authors.lastname: Zapletal
authors.forename: Anamaria
authors.initials: A
authors.lastname: Brozovic
mesh_terms: D000818:Animals; D045744:Cell Line, Tumor; D004399:Dynorphins / Q000494:pharmacology; D005786:Gene Expression Regulation / Q000276:immunology; D006801:Humans; D018836:Inflammation Mediators / Q000502:physiology; D007371:Interferon-gamma / Q000502:physiology*; D008264:Macrophages / Q000276:immunology*; D051379:Mice; D008807:Mice, Inbred BALB C; D048052:Mitogen-Activated Protein Kinase 3 / Q000378:metabolism; D018377:Neurotransmitter Agents / Q000494:pharmacology; D010766:Phosphorylation / Q000235:genetics / Q000276:immunology; D017473:Receptors, Opioid, kappa / Q000096:biosynthesis* / Q000235:genetics / Q000502:physiology; D015398:Signal Transduction / Q000235:genetics / Q000276:immunology; D020298:U937 Cells; D015854:Up-Regulation / Q000235:genetics / Q000276:immunology*
chemical_list: D018836:Inflammation Mediators; D018377:Neurotransmitter Agents; D017473:Receptors, Opioid, kappa; D004399:Dynorphins; D007371:Interferon-gamma; D048052:Mitogen-Activated Protein Kinase 3