This result indicates that NF-κB and MAPK are involved in the gDNA-mediated signaling pathway (Fig. 3a). LPS-mediated phosphorylation of NF-κB, p38, ERK 1/2, and JNK 1/2 in THP-1 cells was increased after 15 min treatment, and optimal responses were reached after 30 min of LPS stimulation. NF-κB and MAPK phosphorylation, however, were significantly inhibited in p-gDNA- or a-gDNA pretreated THP-1 cells followed by re-stimulation with 0.5 μg mL−1 LPS (Fig. 3b and c). We also evaluated differences between p-gDNA and a-gDNA in signaling transduction. The phosphorylation of NF-κB, p38, ERK 1/2 and JNK 1/2 was increased by a-gDNA, whereas p-gDNA treatment

barely induced phosphorylation of those molecules (Fig. 3d). These results suggest that the activation of MAPK and NF-κB is involved in LPS-induced TNF-α production, and that gDNA inhibits TNF-α production through the downregulation of signaling transduction learn more associated with the NF-κB and MAPK pathways. LPS induces septic shock through pattern recognition receptors (PRRs), especially

TLR4 (Lakhani & Bogue, 2003). Therefore, we examined the role of gDNA pretreatment on the expression of PRRs. The mRNA level GW-572016 nmr of TLR2, TLR4 and TLR9 was downregulated in THP-1 cells pretreated with gDNA followed by re-stimulation with 0.5 μg mL−1 LPS for 4 h. LPS increased TLR expression after 15 min, whereas TLR expression was reduced in THP-1 cells pretreated with p-gDNA or a-gDNA compared to LPS alone (Fig. 4a and b). Extracellular treatment of THP-1 cells with gDNA induced TLR2, TLR4 and TLR9 expression, although there were differences between strains. Expression levels of TLR2 and TLR9 after a-gDNA treatment were higher than after p-gDNA treatment. A low level of TLR4 expression was shown in both p-gDNA- and a-gDNA-treated cells; however, it was slightly increased by p-gDNA in a time-dependent manner, and a-gDNA showed a tendency

to decrease after reaching a peak at 15 min (Fig. 4c). Although both p-gDNA and a-gDNA reduced LPS-induced TNF-α production, mafosfamide they displayed different trends in TNF-α induction. To further evaluate the differences between p-gDNA and a-gDNA, we examined the variation of TLR-negative regulators and examined the mRNA levels of IRAK-M, IRAK4, IRAK1 and IRAK2 in THP-1 cells. IRAK-M blocks the pathway in which IRAK4 is processed to IRAK1, and IRAK1 promotes IRAK2. The expression of IRAK-M increased along with treatment time in p-gDNA-treated cells, whereas it peaked at 30 min after treatment with a-gDNA and then slightly declined (Fig. 5a). IRAK-M blocked IRAK4 activation and subsequent IRAK1 phosphorylation (Miggin & O’Neill, 2006). When THP-1 cells were treated with p-gDNA, IRAK-4 was increased in a time-dependent manner, whereas IRAK1 and IRAK2 increased slightly and then disappeared after about 120 min.