Role of protein haptenation in triggering maturation events in the dendritic cell surrogate cell line THP-1.
Dendritic cell (DC) maturation in response to contact sensitizers is a crucial step in the induction of sensitization reactions; however the underlying mechanism of activation remains unknown. To test whether the extent of protein haptenation is a determinant in DC maturation, we tested the effect of five dinitrophenyl (DNP) analogues of different reactivity, on maturation markers in the cell line, THP-1. The potencies of the test compounds in upregulating CD54 levels, inducing IL-8 release and triggering p38 MAPK phosphorylation did not correlate with their ability to deplete intracellular glutathione (GSH) levels or cause cell toxicity. However, the compounds' potency at inducing p38 phosphorylation was significantly associated with the amount of intracellular protein adducts formed (p<0.05). Inhibition experiments show that, at least for DNFB, p38 MAP kinase signalling controls compound-specific changes in CD54 expression and IL-8 release. 2D-PAGE analysis revealed that all the DNP analogues appeared to bind similar proteins. The analogues failed to activate NFkB, however, they activated Nrf2, which was used as a marker of oxidative stress. Neither GSH depletion, by use of buthionine sulfoximine, nor treatment with the strongly lysine-reactive hapten penicillin elicited maturation. We conclude that protein haptenation, probably through reactive cysteine residues may be a trigger for maturation events in this in vitro model and that p38 activation may be a discriminatory marker for the classification of potency of chemical sensitizers.
MRC Centre for Drug Safety Science, The University of Liverpool, Department of Pharmacology and Therapeutics, Ashton Street, Liverpool, L69 3GE, UK.
Rym
R
Megherbi
Evanthia
E
Kiorpelidou
Brian
B
Foster
Cliff
C
Rowe
Dean J
DJ
Naisbitt
Christopher E
CE
Goldring
B Kevin
BK
Park
D017951:Antigen Presentation / Q000187:drug effects* / Q000276:immunology; D045744:Cell Line, Tumor; D003713:Dendritic Cells / Q000166:cytology / Q000187:drug effects / Q000276:immunology* / Q000378:metabolism; D017449:Dermatitis, Allergic Contact / Q000276:immunology* / Q000378:metabolism; D004136:Dinitrobenzenes / Q000276:immunology / Q000494:pharmacology*; D005978:Glutathione / Q000378:metabolism; D006241:Haptens / Q000187:drug effects* / Q000276:immunology / Q000378:metabolism; D006801:Humans; D007948:Leukemia, Monocytic, Acute; D015398:Signal Transduction / Q000187:drug effects / Q000276:immunology; D015262:Xenobiotics / Q000276:immunology; D048051:p38 Mitogen-Activated Protein Kinases / Q000187:drug effects / Q000276:immunology / Q000378:metabolism
D004136:Dinitrobenzenes; D006241:Haptens; D015262:Xenobiotics; D048051:p38 Mitogen-Activated Protein Kinases; D005978:Glutathione