CD40 and OX40 ligand are differentially regulated on asthmatic airway smooth muscle.
BACKGROUND
CD40 and OX40 Ligand (OX40L) are cell-surface molecules expressed on airway smooth muscle (ASM) that can enhance inflammatory cell activation and survival. The aim of this study was to examine the effect of tumour necrosis factor-alpha (TNF-alpha) and interferon-gamma (IFN-gamma) on ASM CD40 and OX40L expression.


METHODS
CD40 and OX40L expression on human ASM cells from asthmatic and nonasthmatic donors following stimulation with TNF-alpha and/or IFN-gamma was measured using cell-surface enzyme-linked immunosorbent assay (ELISA) and flow cytometry. Involvement of signalling pathway was investigated with pharmacological inhibitors. Soluble TNF receptor levels were quantified by ELISA.


RESULTS
Interferon-gamma and TNF-alpha synergistically increased CD40 expression to a greater extent on asthmatic than on nonasthmatic ASM. In contrast, IFN-gamma reduced TNF-alpha-induced OX40L expression to a similar extent in both cell types. TNF-alpha and IFN-gamma induced CD40 via nuclear factor-kappaB (NF-kappaB) and signal transducer and activator of transcription-3 in both cell types and modulated OX40L via NF-kappaB and c-Jun N terminal kinase in nonasthmatic cells. Similar effects on the induction of OX40L in asthmatic cells were seen with NF-kappaB, but these were not statistically significant. The reduced OX40L expression with TNF-alpha and IFN-gamma involved extracellular regulated kinase 1/2 activation.


CONCLUSIONS
Asthmatic ASM may modulate airway inflammation locally by increasing CD40 and OX40L expression in response to cytokines. IFN-gamma may regulate ASM pro-inflammatory actions by differentially modulating ASM CD40 and OX40L expression.
Krimmer
D I
DI
Discipline of Pharmacology, The University of Sydney, Sydney, NSW 2006, Australia.
Loseli
M
M
Hughes
J M
JM
Oliver
B G G
BG
Moir
L M
LM
Hunt
N H
NH
Black
J L
JL
Burgess
J K
JK
D000328:Adult; D000368:Aged; D001249:Asthma / Q000276:immunology* / Q000378:metabolism; D019013:CD40 Antigens / Q000819:agonists / Q000276:immunology / Q000378:metabolism*; D004357:Drug Synergism; D004791:Enzyme Inhibitors / Q000494:pharmacology; D048049:Extracellular Signal-Regulated MAP Kinases / Q000187:drug effects / Q000276:immunology / Q000378:metabolism; D006801:Humans; D007371:Interferon-gamma / Q000494:pharmacology*; D048670:MAP Kinase Kinase 4 / Q000187:drug effects / Q000276:immunology / Q000378:metabolism; D008875:Middle Aged; D032389:Myocytes, Smooth Muscle / Q000187:drug effects* / Q000276:immunology; D016328:NF-kappa B / Q000187:drug effects / Q000276:immunology / Q000378:metabolism; D053278:OX40 Ligand / Q000037:antagonists & inhibitors / Q000276:immunology / Q000378:metabolism*; D050796:STAT3 Transcription Factor / Q000187:drug effects / Q000276:immunology / Q000378:metabolism; D015398:Signal Transduction / Q000187:drug effects / Q000276:immunology; D014409:Tumor Necrosis Factor-alpha / Q000494:pharmacology*
D019013:CD40 Antigens; D004791:Enzyme Inhibitors; D016328:NF-kappa B; D053278:OX40 Ligand; D050796:STAT3 Transcription Factor; C494086:STAT3 protein, human; D014409:Tumor Necrosis Factor-alpha; D007371:Interferon-gamma; D048049:Extracellular Signal-Regulated MAP Kinases; D048670:MAP Kinase Kinase 4