Glycated human serum albumin induces interleukin 8 mRNA expression through reactive oxygen species and NADPH oxidase-dependent pathway in monocyte-derived U937 cells.
Glycated human serum albumin (Glc-HSA) has previously been reported (Higai K., et al., 2006) to induce E-selectin expression on human umbilical vein endothelial cells through activation of NADPH oxidase; however, Glc-HSA signaling in monocytes remains obscure. To clarify the influence on human monocyte-derived U937 cells, U937 cells were stimulated with Glc-HSA and glycoaldehyde-dimer-modified HSA (GA-HSA) for 2 h in the absence and presence of the protein kinase C (PKC) inhibitor calphostin and the reactive oxygen species (ROS) scavenger N-acetyl-L-cysteine (NAC) and NADPH oxidase inhibitor apocynin; interleukin-8 (IL-8) mRNA expression was determined by RT-PCR. As a result, IL-8 mRNA expression in U-937 cells was time- and dose-dependently enhanced by stimulation with Glc-HSA and GA-HSA. Furthermore, promoter activity of the IL-8 reporter gene was enhanced approximately 2-fold by stimulation with Glc-HSA and GA-HSA. Nuclear factor kappaB (NFkappaB) and activator protein-1 (AP-1) reporter genes were also enhanced although CCAAT/enhancer binding protein (C/EBP) was not affected. IL-8 mRNA expression was suppressed by NAC and apocynin but not calphostin in cells stimulated with Glc-HSA; however, its expression in cells stimulated with GA-HSA was suppressed by calphostin but not NAC. These results indicated that IL-8 mRNA expression was upregulated by NFkappaB and AP-1 in U937 cells stimulated with Glc-HSA and GA-HSA, but the signaling pathways were different.
Higai
Koji
K
Department of Clinical Chemistry, School of Pharmaceutical Sciences, Toho University, Funahashi, Chiba, Japan. koji@phar.toho-u.ac.jp
Sano
Risa
R
Satake
Misaki
M
Azuma
Yutaro
Y
Matsumoto
Kojiro
K
D022762:CCAAT-Enhancer-Binding Proteins / Q000096:biosynthesis / Q000235:genetics; D018076:DNA, Complementary / Q000096:biosynthesis / Q000235:genetics; D019040:E-Selectin / Q000096:biosynthesis; D017930:Genes, Reporter / Q000235:genetics; D006801:Humans; D016209:Interleukin-8 / Q000096:biosynthesis*; D008156:Luciferases / Q000096:biosynthesis; D009000:Monocytes / Q000187:drug effects / Q000378:metabolism*; D019255:NADPH Oxidases / Q000502:physiology*; D016328:NF-kappa B / Q000096:biosynthesis; D012333:RNA, Messenger / Q000096:biosynthesis* / Q000235:genetics; D017382:Reactive Oxygen Species / Q000378:metabolism*; D020133:Reverse Transcriptase Polymerase Chain Reaction; D012709:Serum Albumin / Q000494:pharmacology*; D015398:Signal Transduction / Q000235:genetics / Q000502:physiology; D013268:Stimulation, Chemical; D018808:Transcription Factor AP-1 / Q000235:genetics; D020298:U937 Cells
D022762:CCAAT-Enhancer-Binding Proteins; D018076:DNA, Complementary; D019040:E-Selectin; D016209:Interleukin-8; D016328:NF-kappa B; D012333:RNA, Messenger; D017382:Reactive Oxygen Species; D012709:Serum Albumin; D018808:Transcription Factor AP-1; D008156:Luciferases; D019255:NADPH Oxidases