HMOX1 and NQO1 genes are upregulated in response to contact sensitizers in dendritic cells and THP-1 cell line: role of the Keap1/Nrf2 pathway.
Electrophilicity is one of the most common features of skin contact sensitizers and is necessary for protein haptenation. The Keap1 (Kelch-like ECH-associated protein 1)/Nrf2 -signaling pathway is dedicated to the detection of electrophilic stress in cells leading to the upregulation of genes involved in protection or neutralization of chemical reactive species. Signals provided by chemical stress could play an important role in dendritic cell activation and the aim of this work was to test whether contact sensitizers were specific activators of the Keap1/Nrf2 pathway. CD34-derived dendritic cells (CD34-DC) and the THP-1 myeloid cell line were treated by a panel of sensitizers (Ni, 1-chloro 2,4-dinitrobenzene, cinnamaldehyde, 7-hydroxycitronellal, 1,4-dihydroquinone, alpha-methyl-trans-cinnamaldehyde, 2-4-tert-(butylbenzyl)propionaldehyde or Lilial, and 1,4-phenylenediamine), irritants (sodium dodecyl sulfate, benzalkonium chloride), and a nonsensitizer molecule (chlorobenzene). Three well-known Nrf2 activators (tert-butylhydroquinone, lipoic acid, sulforaphane) were also tested. Expression of hmox1 and nqo1 was measured using real-time PCR and cellular accumulation of Nrf2 was assessed by Western blot. Our results showed an increased expression at early time points of hmox1 and nqo1 mRNAs in response to sensitizers but not to irritants. Accumulation of the Nrf2 protein was also observed only with chemical sensitizers. A significant inhibition of the expression of hmox1 and nqo1 mRNAs and CD86 expression was found in 1-chloro 2,4-dinitrobenzene-treated THP-1 cells preincubated with N-acetyl cysteine, a glutathione precursor. Altogether, these data suggested that the Keap1/Nrf2-signaling pathway was activated by electrophilic molecules including sensitizers in dendritic cells and in the THP-1 cell line. Monitoring of this pathway may provide new biomarkers (e.g., Nrf2, hmox1) for the detection of the sensitization potential of chemicals.
Ade
Nadège
N
University of Paris-Sud, INSERM UMR-S 749, Faculté de Pharmacie Paris-Sud, 5, rue JB Clément, F-92296 Châtenay-Malabry, France.
Leon
Fanny
F
Pallardy
Marc
M
Peiffer
Jean-Luc
JL
Kerdine-Romer
Saadia
S
Tissier
Marie-Hélène
MH
Bonnet
Pierre-Antoine
PA
Fabre
Isabelle
I
Ourlin
Jean-Claude
JC
D018952:Antigens, CD34 / Q000235:genetics; D051940:B7-2 Antigen / Q000096:biosynthesis / Q000235:genetics; D015153:Blotting, Western; D002460:Cell Line; D003553:Cystine / Q000031:analogs & derivatives / Q000494:pharmacology; D003713:Dendritic Cells / Q000187:drug effects* / Q000378:metabolism*; D003877:Dermatitis, Contact / Q000235:genetics*; D005312:Fetal Blood / Q000166:cytology; D005434:Flow Cytometry; D051547:Heme Oxygenase-1 / Q000235:genetics*; D006801:Humans; D047908:Intracellular Signaling Peptides and Proteins / Q000235:genetics*; D007509:Irritants / Q000633:toxicity*; D000072019:Kelch-Like ECH-Associated Protein 1; D016660:NAD(P)H Dehydrogenase (Quinone) / Q000235:genetics*; D051267:NF-E2-Related Factor 2 / Q000235:genetics*; D012333:RNA, Messenger / Q000096:biosynthesis / Q000235:genetics; D020133:Reverse Transcriptase Polymerase Chain Reaction; D015398:Signal Transduction / Q000187:drug effects / Q000235:genetics; D012867:Skin / Q000378:metabolism; D015854:Up-Regulation / Q000187:drug effects
D018952:Antigens, CD34; D051940:B7-2 Antigen; D047908:Intracellular Signaling Peptides and Proteins; D007509:Irritants; C431364:KEAP1 protein, human; D000072019:Kelch-Like ECH-Associated Protein 1; D051267:NF-E2-Related Factor 2; C495635:NFE2L2 protein, human; D012333:RNA, Messenger; D003553:Cystine; C496541:HMOX1 protein, human; D051547:Heme Oxygenase-1; D016660:NAD(P)H Dehydrogenase (Quinone); C447479:NQO1 protein, human; C030905:N-monoacetylcystine