Efficacy of horse oil on lipopolysaccharide-induced inflammation in human keratinocyte.

OBJECTIVE: To investigate the efficacy of horse oil on lipopolysaccharide (LPS)-induced inflammation in human keratinocytes. METHODS: Western blot analysis was performed to measure the expression of cyclooxygenase-2 (COX-2) and IκBα. ELISA was used to analyze prostaglandin E2 (PGE2) levels. RESULTS: Horse oil decreased LPS-induced COX-2 and PGE2 levels in a dose-dependent manner. Nuclear factor-kappa B (NF-κB) plays a key role in the expression of inflammatory cytokines and mediators. Therefore, we investigated the influence of horse oil on the NF-κB signaling pathways. Horse oil inhibited translocation of NF-κB from the cytosol to the nucleus. Furthermore, LPS-induced degradation of IκBα was recovered by horse oil. The activation of p38 mitogen-activated protein kinase (MAPK) reportedly induces degradation of IκBα In agreement with this, LPS activated p38 MAPK and caused IκBα degradation. Conversely, horse oil inhibited LPS-induced p38 MAPK activation and IκBα degradation. In addition, a specific p38 MAPK inhibitor, SB203580, blocked IκBα degradation. CONCLUSION: Horse oil decreased COX-2 and PGE2 by inhibiting p38 MAPK activation, IκBα degradation, and the translocation of NF-κB.

DNA methyltransferase DNMT1 inhibits lipopolysaccharide­induced inflammatory response in human dental pulp cells involving the methylation changes of IL­6 and TRAF6.

Dental pulp inflammation is a pathological process characterized by local lesions in dental pulp and the accumulation of inflammatory mediators. DNA methylation of cytosine residues is a key epigenetic modification that is essential for gene transcription, and plays pivotal roles in inflammatory reactions and immune responses. However, the function of cytosine DNA methylation in the innate immune defense against the inflammation of dental pulp is poorly understood. To investigate the effect of DNA methylation in inflamed dental pulp upon innate immune responses, expression levels of the DNA methyltransferases (DNMT1, DNMT3a and DNMT3b) in human dental pulp cells (hDPCs) after lipopolysaccharide (LPS) stimulation were evaluated by western blotting and reverse transcription­quantitative (RT­q) PCR. Only DNMT1 expression was decreased, while the transcription of inflammatory cytokines was increased. In the immune responses of LPS­induced hDPCs, the results of RT­qPCR and ELISA showed that DNMT1 knockdown promoted the production of the pro­inflammatory cytokines, interleukin (IL)­6 and IL­8. Western blotting demonstrated that DNMT1 knockdown increased the phosphorylation levels of IKKα/ß and p38 in the NF­κB and MAPK signaling pathways, respectively. Furthermore, MeDIP and RT­qPCR analysis demonstrated that the 5­methylcytosine levels of the IL­6 and TNF receptor­associated factor 6 (TRAF6) promoters were significantly decreased in DNMT1­deficient hDPCs. Taken together, these results indicated that the expression of DNMT1 was decreased after LPS stimulation in hDPCs. DNMT1 depletion increased LPS­induced cytokine secretion, and activated NF­κB and MAPK signaling; these mechanisms may involve the decreased methylation levels of the IL­6 and TRAF6 gene promoters. This study emphasized the role of DNMT1­dependent DNA methylation on the inflammation of LPS­infected dental pulp and provides a new rationale for the investigation of the molecular mechanisms of inflamed dental pulps.

Expression of Cyp2c/Cyp2j subfamily members and oxylipin levels during LPS-induced inflammation and resolution in mice.

Inflammatory stimuli, such as bacterial LPS, alter the expression of many cytochromes P450. CYP2C and CYP2J subfamily members actively metabolize fatty acids to bioactive eicosanoids, which exhibit potent anti-inflammatory effects. Herein, we examined mRNA levels of the 15 mouse Cyp2c and 7 mouse Cyp2j isoforms in liver, kidney, duodenum, and brain over a 96-h time course of LPS-induced inflammation and resolution. Plasma and liver eicosanoid levels were also measured by liquid chromatography with tandem mass spectrometry. Expression changes in Cyp2c and Cyp2j isoforms were both isoform and tissue specific. Total liver Cyp2c and Cyp2j mRNA content was reduced by 80% 24 h after LPS but recovered to baseline levels by 96 h. Total Cyp2c and Cyp2j mRNA in kidney (-19%) and duodenum (-64%) were reduced 24 h after LPS but recovered above baseline by 72 h. Total Cyp2c and Cyp2j mRNA content in brain was elevated at all time points after LPS dosing. Plasma eicosanoids transiently increased 3-6 h after administration of LPS. In liver, esterified oxylipin levels decreased during acute inflammation and before recovering. The biphasic suppression and recovery of mouse Cyp2c and Cyp2j isoforms and associated changes in eicosanoid levels during LPS-induced inflammation and resolution may have important physiologic consequences.-Graves, J. P., Bradbury, J. A., Gruzdev, A., Li, H., Duval, C., Lih, F. B., Edin, M. L., Zeldin, D. C. Expression of Cyp2c/Cyp2j subfamily members and oxylipin levels during LPS-induced inflammation and resolution in mice.

Ebselen suppresses inflammation induced by Helicobacter pylori lipopolysaccharide via the p38 mitogen-activated protein kinase signaling pathway.

Ebselen is a seleno-organic compound that has been demonstrated to have antioxidant and anti-inflammatory properties. A previous study determined that ebselen inhibits airway inflammation induced by inhalational lipopolysaccharide (LPS), however, the underlying molecular mechanism remains to be elucidated. The present study investigated the effect of ebselen on the glutathione peroxidase (GPX)­reactive oxygen species (ROS) pathway and interleukin­8 (IL­8) expression induced by Helicobacter pylori LPS in gastric cancer (GC) cells. Cells were treated with 200 ng/ml H. pylori­LPS in the presence or absence of ebselen for various durations and concentrations (µmol/l). The expression of toll­like receptor 4 (TLR4), GPX2, GPX4, p38 mitogen­activated protein kinase (p38 MAPK), phosphorylated­p38 MAPK, ROS production and IL­8 expression were detected with western blotting or ELISA. The present study revealed that TLR4 expression was upregulated; however, GPX2 and GPX4 expression was reduced following treatment with H. pylori LPS, which led to increased ROS production, subsequently altering the IL­8 expression level in GC cells. Additionally, it was determined that ebselen prevented the reduction in GPX2/4 levels induced by H. pylori LPS, however, TLR4 expression was not affected. Ebselen may also block the expression of IL­8 by inhibiting phosphorylation of p38 MAPK. These data suggest ebselen may inhibit ROS production triggered by H. pylori LPS treatment via GPX2/4 instead of TLR4 signaling and reduce phosphorylation of p38 MAPK, resulting in altered production of IL­8. Ebselen may, therefore, be a potential therapeutic agent to mediate H. pylori LPS-induced cell damage.