title: Morphine negatively regulates interferon-gamma promoter activity in activated murine T cells through two distinct cyclic AMP-dependent pathways.
abstract: To explore the mechanism by which morphine promotes the incidence of HIV infection, we evaluated the regulatory role of morphine on the interferon-gamma (IFN-gamma) promoter in activated T cells from wild type and mu-opioid receptor knockout mice. Our results show that morphine inhibited anti-CD3/CD28-stimulated IFN-gamma promoter activity in a dose-dependent manner. Chronic morphine treatment of T cells increased intracellular cAMP. To evaluate the role of cAMP in morphine's modulatory function, the effects of dibutyryl cyclic AMP and forskolin were investigated. Both dibutyryl cyclic AMP and forskolin treatment inhibited IFN-gamma promoter activity. Treatment with pertussis toxin, but not with a protein kinase A inhibitor, antagonized morphine's inhibitory effects. Morphine inhibited phosphorylation of ERK1/2 and p38 MAPK; in addition, morphine treatment in the presence of either ERK1/2 or p38 MAPK inhibitor (PD98059 or SB203580) resulted in an additive inhibition of IFN-gamma promoter activity. The transcription factor activator protein-1, NF-kappaB, and nuclear factor of activated T cells (NFAT) were negatively regulated by morphine. Overexpression of NF-kappaB p65 rescued the inhibitory effect of morphine on IFN-gamma promoter activity. However, only when NFATc1 was co-overexpressed with c-fos was the inhibitory effect of morphine on IFN-gamma promoter counteracted. The inhibitory effects of morphine were not observed in T cells obtained from mu-opioid receptor knockout mice, suggesting that morphine modulation of IFN-gamma promoter activity is mediated through the mu-opioid receptor. In summary, our data indicate that morphine modulation of IFN-gamma promoter activity is mediated through two distinct cAMP-dependent pathways, the NF-kappaB signaling pathway and the ERK1/2, p38 MAPK, AP-1/NFAT pathway.
authors.affiliation: Department of Pharmacology, University of Minnesota, Minneapolis, Minnesota 55455, USA.
authors.forename: Jinghua
authors.initials: J
authors.lastname: Wang
authors.forename: Roderick A
authors.initials: RA
authors.lastname: Barke
authors.forename: Richard
authors.initials: R
authors.lastname: Charboneau
authors.forename: Horace H
authors.initials: HH
authors.lastname: Loh
authors.forename: Sabita
authors.initials: S
authors.lastname: Roy
mesh_terms: D000818:Animals; D018106:CD28 Antigens / Q000502:physiology; D000242:Cyclic AMP / Q000502:physiology*; D054746:Cyclic AMP-Dependent Protein Kinase Type II; D017868:Cyclic AMP-Dependent Protein Kinases / Q000502:physiology; D004268:DNA-Binding Proteins / Q000378:metabolism; D007371:Interferon-gamma / Q000235:genetics*; D008213:Lymphocyte Activation; D051379:Mice; D008807:Mice, Inbred BALB C; D020928:Mitogen-Activated Protein Kinases / Q000502:physiology; D009020:Morphine / Q000494:pharmacology*; D016328:NF-kappa B / Q000378:metabolism; D050778:NFATC Transcription Factors; D009687:Nuclear Proteins; D011401:Promoter Regions, Genetic / Q000187:drug effects*; D016760:Proto-Oncogene Proteins c-fos / Q000032:analysis; D015398:Signal Transduction / Q000187:drug effects*; D013601:T-Lymphocytes / Q000378:metabolism*; D018808:Transcription Factor AP-1 / Q000378:metabolism; D014157:Transcription Factors / Q000378:metabolism; D048051:p38 Mitogen-Activated Protein Kinases
chemical_list: D018106:CD28 Antigens; D004268:DNA-Binding Proteins; D016328:NF-kappa B; D050778:NFATC Transcription Factors; C494005:Nfatc1 protein, mouse; D009687:Nuclear Proteins; D016760:Proto-Oncogene Proteins c-fos; D018808:Transcription Factor AP-1; D014157:Transcription Factors; D009020:Morphine; D007371:Interferon-gamma; D000242:Cyclic AMP; D054746:Cyclic AMP-Dependent Protein Kinase Type II; D017868:Cyclic AMP-Dependent Protein Kinases; D020928:Mitogen-Activated Protein Kinases; D048051:p38 Mitogen-Activated Protein Kinases