Meanwhile, a number of studies have also shown that the mitogen-activated protein kinases (MAPKs, including ERK, JNK and p38) signal transduction pathways mediate

a variety of stimulating factors-induced IL-8 expression [4, 16–18]. NF-κB is a ubiquitous pleiotropic transcription factor. Studies have shown that NF-κΒ activation is a contributing factor for a variety of lung diseases and lung inflammation [19–21]. Pyrrolidine dithiocarbamate, a metal chelator and antioxidant, can inhibit the activation of NF-kB specifically by suppressing the release of the inhibitory subunit Ik-B from the latent cytoplasmic form of NF-kB. Recent studies have indicated that maximal IL-8 protein expression requires activation of NF-κB as well as MAPKs [17]. However, the precise relationship #learn more randurls[1|1|,|CHEM1|]# between NF-κB transactivation and MAPK activation remains unclear. In addition, few cellular pathways that are affected by PCN are known. Hence, the present study was designed to testify whether PCN can provoke the activation of macrophages, and whether NF-κB and MAPKs are involved in this possible process. Methods Chemicals and reagents RPMI-1640, fetal bovine serum (FBS), and antibiotics were purchased from GIBCO

BRL (Grand Island, NY). Phospho-specific p38 MAPK and p38, check details and phospho-specific ERK1/2 and ERK1/2 were from New EnglandBiolabs (Bevely, MA). Stocks of the selective p38 MAPK inhibitor SB203580, and stocks of the selective ERK1/2 inhibitor PD98059 were purchased from Calbio-chem-Behring (Za Jolla, CA). Phospho-NF-κB p65 (Ser276) antibody was purchased Tryptophan synthase from Cell Signaling Technology (CST, Danvers, MA) and anti-p-IκB-α (Ser32) from Santa Cruz Biotechnology (Santa Cruz, CA) . IL-8 assay kit and TNF-α were purchased from R&D Systems (Minneapolis, MN). PMA was purchased from Merck Biosciences (San Diego, CA). PMS (phenazinem ethosulfate, molecular formula: C14H14N2O4S) was from AMRESCO (Solon, OH). NF-κB inhibitor PDTC, PCN,

N-acetylcysteine, LDH, SOD,CAT, and MDA assay kits were purchased from Sigma Chemical Co. (St. Louis, MO). All other reagents, unless specified, were purchased from Sigma Chemical Co. Cell culture and differentiation U937 cells were purchased from ATCC (American Type Culture Collection, Rockville, MD) and were cultured at 37°C in a humidified atmosphere with 5% CO2 in RPMI 1640 medium supplemented with 10% FCS and 50 μg/mL gentamicin, which itself was supplemented with 4.5 g/L glucose, 1 mM sodium pyruvate, and 10 mM HEPES. Cell culture was maintained at a density of 1 × 106 cells/mL. All cell lines were diluted one day before each experiment. For differentiation into macrophages, U937 cells were treated with PMA (10 nM) and allowed to adhere for 48 h in a 5% CO2 tissue culture incubator at 37°C, after which they were washed and fed with PMA-free medium.