title: Morphine withdrawal stress modulates lipopolysaccharide-induced interleukin 12 p40 (IL-12p40) expression by activating extracellular signal-regulated kinase 1/2, which is further potentiated by glucocorticoids.
abstract: Withdrawal stress is a common occurrence in opioid users, yet very few studies have examined the effects of morphine withdrawal (MW) on immune functioning or the role of glucocorticoids in MW-induced immunomodulation. This study investigated for the first time the role of glucocorticoids in MW modulation of LPS-induced IL-12p40, a key cytokine playing a pivotal role in immunoprotection. Using WT and μ-opioid receptor knock-out mice, we show that MW in vivo significantly attenuated LPS-induced IL-12p40 mRNA and protein expression. The role of glucocorticoids in MW modulation of IL-12p40 was investigated using a murine macrophage cell line, CRL2019, in an in vitro MW model. Interestingly, MW alone in the absence of glucocorticoids resulted in a significant reduction in IL-12p40 promoter activity and mRNA and protein expression. EMSA revealed a concurrent decrease in consensus binding to transcription factors NFκB, Activator Protein-1, and CCAAT/enhancer-binding protein and Western blot analysis demonstrated a significant activation of LPS-induced ERK1/2 phosphorylation. Interestingly, although glucocorticoid treatment alone also modulated these transcription factors and ERK1/2 activation, the addition of glucocorticoids to MW samples resulted in a greater than additive reduction in the transcription factors and significant hyperactivation of LPS-induced ERK1/2 phosphorylation. ERK inhibitors reversed MW and MW plus corticosterone inhibition of LPS-induced IL-12p40. The potentiating effects of glucocorticoids were non-genomic because nuclear translocation of glucocorticoid receptor was not significantly different between MW and corticosterone treatment. This study demonstrates for the first time that MW and glucocorticoids independently modulate IL-12p40 production through a mechanism involving ERK1/2 hyperactivation and that glucocorticoids can significantly augment MW-induced inhibition of IL-12p40.
authors: Department of Surgery, University of Minnesota, Minneapolis, Minnesota 55455, USA.
authors: Subhas
authors: S
authors: Das
authors: Jennifer
authors: J
authors: Kelschenbach
authors: Richard
authors: R
authors: Charboneau
authors: Roderick A
authors: RA
authors: Barke
authors: Sabita
authors: S
authors: Roy
mesh_terms: D000818:Animals; D023081:CCAAT-Binding Factor / Q000235:genetics / Q000378:metabolism; D002460:Cell Line; D004789:Enzyme Activation; D004791:Enzyme Inhibitors / Q000494:pharmacology; D005786:Gene Expression Regulation / Q000187:drug effects*; D005938:Glucocorticoids / Q000494:pharmacology*; D053762:Interleukin-12 Subunit p40 / Q000096:biosynthesis* / Q000235:genetics; D008070:Lipopolysaccharides / Q000494:pharmacology*; D008297:Male; D051379:Mice; D048052:Mitogen-Activated Protein Kinase 3 / Q000235:genetics / Q000378:metabolism*; D009020:Morphine; D010766:Phosphorylation / Q000187:drug effects / Q000235:genetics; D011965:Receptors, Glucocorticoid / Q000235:genetics / Q000378:metabolism; D013312:Stress, Physiological; D013375:Substance Withdrawal Syndrome / Q000235:genetics / Q000378:metabolism*; D018808:Transcription Factor AP-1 / Q000235:genetics / Q000378:metabolism
chemical_list: D023081:CCAAT-Binding Factor; D004791:Enzyme Inhibitors; D005938:Glucocorticoids; D053762:Interleukin-12 Subunit p40; D008070:Lipopolysaccharides; D011965:Receptors, Glucocorticoid; D018808:Transcription Factor AP-1; D009020:Morphine; D048052:Mitogen-Activated Protein Kinase 3