title: Glucocorticoid regulation of CD38 expression in human airway smooth muscle cells: role of dual specificity phosphatase 1.
abstract: The enzymatic activity of CD38, ADP-ribosyl cyclase, synthesizes the calcium mobilizing molecule cyclic ADP-ribose from beta-NAD. In human airway smooth muscle (HASM) cells, CD38 expression is augmented by the inflammatory cytokine, TNF-alpha, causing increased intracellular calcium response to agonists. The transcriptional and posttranscriptional regulation of CD38 expression involves signaling through MAPKs and requires activation of NF-kappaB and activator protein-1 (AP-1). The cytokine-augmented CD38 expression is decreased by anti-inflammatory glucocorticoids due to inhibition of NF-kappaB activation and other mechanisms. In this study, we investigated glucocorticoid regulation of CD38 expression in HASM cells through the MKP-1. In HASM cells, dexamethasone and TNF-alpha induced MKP-1 expression (both mRNA and protein) rapidly. Dexamethasone decreased TNF-alpha-induced phosphorylation of the major MAPKs, i.e., ERK, p38, and JNK, and decreased the activation of NF-kappaB and AP-1. Dexamethasone also decreased CD38 expression induced by TNF-alpha, and part of this effect was attributable to decreased transcript stability. In cells transfected with MKP-1-specific small interfering RNAs (siRNAs), there was significant attenuation of MKP-1 expression and partial, but nonsignificant, reversal of dexamethasone inhibition of CD38 expression. These results indicate that regulation of CD38 expression in HASM cells by glucocorticoids involves decreased signaling through MAPKs and activation of transcription factors. The glucocorticoid effects on decreased CD38 expression and function result from regulation through transcription and transcript stability.
authors.affiliation: Department of Veterinary and Biomedical Sciences, University of Minnesota, St. Paul, Minnesota 55108, USA.
authors.forename: Bit Na
authors.initials: BN
authors.lastname: Kang
authors.forename: Joseph A
authors.initials: JA
authors.lastname: Jude
authors.forename: Reynold A
authors.initials: RA
authors.lastname: Panettieri
authors.forename: Timothy F
authors.initials: TF
authors.lastname: Walseth
authors.forename: Mathur S
authors.initials: MS
authors.lastname: Kannan
mesh_terms: D051997:ADP-ribosyl Cyclase 1 / Q000037:antagonists & inhibitors / Q000096:biosynthesis*; D002478:Cells, Cultured; D036563:Cyclic ADP-Ribose / Q000378:metabolism; D003907:Dexamethasone / Q000494:pharmacology*; D054638:Dual Specificity Phosphatase 1 / Q000096:biosynthesis*; D048049:Extracellular Signal-Regulated MAP Kinases / Q000378:metabolism; D015971:Gene Expression Regulation, Enzymologic / Q000187:drug effects* / Q000502:physiology; D005938:Glucocorticoids / Q000494:pharmacology*; D006801:Humans; D020935:MAP Kinase Signaling System / Q000187:drug effects / Q000502:physiology; D008562:Membrane Glycoproteins / Q000037:antagonists & inhibitors / Q000096:biosynthesis*; D032389:Myocytes, Smooth Muscle / Q000166:cytology / Q000201:enzymology*; D009243:NAD / Q000378:metabolism; D016328:NF-kappa B / Q000378:metabolism; D020871:RNA Stability / Q000187:drug effects; D034741:RNA, Small Interfering / Q000494:pharmacology; D012137:Respiratory System / Q000166:cytology / Q000201:enzymology*; D018808:Transcription Factor AP-1 / Q000378:metabolism; D014158:Transcription, Genetic / Q000187:drug effects / Q000502:physiology; D014409:Tumor Necrosis Factor-alpha / Q000494:pharmacology
chemical_list: D005938:Glucocorticoids; D008562:Membrane Glycoproteins; D016328:NF-kappa B; D034741:RNA, Small Interfering; D018808:Transcription Factor AP-1; D014409:Tumor Necrosis Factor-alpha; D009243:NAD; D036563:Cyclic ADP-Ribose; D003907:Dexamethasone; D048049:Extracellular Signal-Regulated MAP Kinases; C517019:DUSP1 protein, human; D054638:Dual Specificity Phosphatase 1; C498154:CD38 protein, human; D051997:ADP-ribosyl Cyclase 1