Protein kinase C stimulates human B cell activating factor gene expression through reactive oxygen species-dependent c-Fos in THP-1 pro-monocytic cells

• Published in: Cytokine (Philadelphia, Pa.) Vol. 59; no. 1; pp. 115 - 123
• Main Authors: Lee, Geun-Hee, Lee, Mi-Hee, Yoon, Yeo-Dae, Kang, Jong-Soon, Pyo, Suhkneung, Moon, Eun-Yi
• Format: Journal Article
• Language: English
• Published: England Elsevier Ltd 01.07.2012
• Subjects: Acetylcysteine; Acetylcysteine - pharmacology; Activator protein 1; Animals; B-Cell Activating Factor - genetics; B-Cell Activating Factor - metabolism; Base Sequence; blood serum; BLyS protein; c-Fos; c-Fos protein; Cell activation; Cell Line; Cercopithecus aethiops; Chromatin; COS Cells; Cyclic AMP response element-binding protein; Cytokines; Data processing; Enzyme Activation - drug effects; Gene expression; Gene Expression Regulation - drug effects; hBAFF; Humans; Hydrogen peroxide; immunologic diseases; Immunological diseases; Immunoprecipitation; integrated circuits; Ionomycin; Ionomycin - pharmacology; Mice; Molecular Sequence Data; Monocytes - drug effects; Monocytes - enzymology; Oligonucleotides; oxygen; Phorbol esters; PKC; precipitin tests; Promoter; Promoter Regions, Genetic - genetics; Promoters; Protein Binding - drug effects; Protein kinase C; Protein Kinase C - metabolism; Proto-Oncogene Proteins c-fos - metabolism; Reactive oxygen species; Reactive Oxygen Species - metabolism; RNA; RNA-mediated interference; ROS; siRNA; Starvation; Staurosporine; Tetradecanoylphorbol Acetate - pharmacology; Transcription Factor AP-1 - metabolism; Transcription factors; transcriptional activation; Transfection; Promoter; BAFF; NAC; PMA; FBS; IOM; ROS; c-Fos; DCF-DA; PKC; hBAFF
• ISSN: 1043-4666; 1096-0023
• DOI: 10.1016/j.cyto.2012.03.017

► We cloned 1.0kb hBAFF promoter into pGL3-basic plasmid to determine transcriptional regulation on hBAFF expression. ► Co-treatment with PMA and ionomycin (IOM) increased hBAFF expression in human monocytes. ► c-Fos-siRNA inhibited PMA/IOM-induced hBAFF expression. ► NAC treatment decreased hBAFF expression through the reduction of PMA/IOM-induced ROS production. ► hBAFF expression was regulated by ROS-dependent c-Fos expression and AP-1 binding to oligosaccharide in promoter. BAFF is associated with various immunological diseases. Previously, we have reported that mouse B cell activating factor (mBAFF) expression was dependent on nuclear localization of co-activator, p300 and the activation of transcription factors including NF-κB and CREB. Here, we investigated whether transcription factor, c-Fos, regulates human (h) BAFF expression through promoter activation by PMA-induced reactive oxygen species (ROS) production. We cloned hBAFF promoter into luciferase-expressing pGL3-basic vector. The activity of 1.0kb hBAFF promoter was higher than that in 0.75, 0.5 or 0.25kb hBAFF promoter. The existence of three AP-1 binding motifs was computer-analyzed in hBAFF promoter. The stimulation with PMA and ionomycin (IOM) increased 1.0kb hBAFF promoter activity, time-dependently. PMA/IOM-stimulation rapidly enhanced c-Fos expression in THP-1 human pro-monocytic cells. Binding of c-Fos to hBAFF promoter was detected by chromatin immunoprecipitation (ChIP) assay. hBAFF expression and its promoter activity were decreased by the transfection with small interference (si) RNA of c-Fos. ROS production in THP-1 cells was increased by PMA/IOM-stimulation. In addition, hBAFF activity stimulated by PMA/IOM was reduced by N-acetyl-cysteine (NAC), a well-known ROS scavenger. Serum starvation (0.5% FBS) producing ROS and the exogenous H2O2 treatment also enhanced hBAFF promoter activity. c-Fos expression and AP-1 binding to oligonucleotide were reduced by the treatment with NAC. H2O2 was not able to induce hBAFF expression in the presence of staurosporine, PKC inhibitor. Data suggest that hBAFF expression could be regulated by promoter activation through c-Fos association, which might be dependent on PMA-induced ROS production.