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A novel chromone derivative with anti-inflammatory property via inhibition of ROS-dependent activation of TRAF6-ASK1-p38 pathway.

Liu H, Xu R, Feng L, Guo W, Cao N, Qian C, Teng P, Wang L, Wu X, Sun Y, Li J, Shen Y, Xu Q - PLoS ONE (2012)

Bottom Line: In the present study, we show that a novel chromone derivative, DCO-6, significantly reduced lipopolysaccharide (LPS)-induced production of nitric oxide, IL-1β and IL-6, decreased the levels of iNOS, IL-1β and IL-6 mRNA expression in both RAW264.7 cells and mouse primary peritoneal macrophages, and inhibited LPS-induced activation of p38 MAPK but not of JNK, ERK.LPS-induced production of intracellular reactive oxygen species (ROS) was remarkably impaired by DCO-6, which disrupted the formation of the TRAF6-ASK1 complex.Our results indicate that DCO-6 showed anti-inflammatory properties through inhibition of ROS-dependent activation of TRAF6-ASK1-p38 pathway.

View Article: PubMed Central - PubMed

Affiliation: State Key Laboratory of Pharmaceutical Biotechnology, School of Life Sciences, Nanjing University, Nanjing, China.

ABSTRACT
The p38 MAPK signaling pathway plays a pivotal role in inflammation. Targeting p38 MAPK may be a potential strategy for the treatment of inflammatory diseases. In the present study, we show that a novel chromone derivative, DCO-6, significantly reduced lipopolysaccharide (LPS)-induced production of nitric oxide, IL-1β and IL-6, decreased the levels of iNOS, IL-1β and IL-6 mRNA expression in both RAW264.7 cells and mouse primary peritoneal macrophages, and inhibited LPS-induced activation of p38 MAPK but not of JNK, ERK. Moreover, DCO-6 specifically inhibited TLR4-dependent p38 activation without directly inhibiting its kinase activity. LPS-induced production of intracellular reactive oxygen species (ROS) was remarkably impaired by DCO-6, which disrupted the formation of the TRAF6-ASK1 complex. Administering DCO-6 significantly protected mice from LPS-induced septic shock in parallel with the inhibition of p38 activation and ROS production. Our results indicate that DCO-6 showed anti-inflammatory properties through inhibition of ROS-dependent activation of TRAF6-ASK1-p38 pathway. Blockade of the upstream events required for p38 MAPK action by DCO-6 may provide a new therapeutic option in the treatment of inflammatory diseases.

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Effects of DCO-6 on the LPS-induced activation of MAPKs and NF-κB in RAW264.7 cells.Cells were treated with various concentrations of DCO-6 in the absence or presence of LPS for 6 h. (A–B) The protein levels of total and phosphorylated p38, JNK, ERK and IKKα, IKKβ, IκBα were determined at least three times, and the representative data are shown. (C) Cytoplasmic and nuclear proteins were extracted and assayed by immunoblotting analysis. Expressions of β-actin and LaminB1 were shown as loading controls. Bands from (A–C) were analyzed by densitometry. Quantitative data are shown. *P<0.05 vs LPS control. (D) Nuclear proteins were extracted and assayed by EMSA. A 75-fold excess of unlabelled oligonucleotide probe and mutant probe were used as controls.
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pone-0037168-g003: Effects of DCO-6 on the LPS-induced activation of MAPKs and NF-κB in RAW264.7 cells.Cells were treated with various concentrations of DCO-6 in the absence or presence of LPS for 6 h. (A–B) The protein levels of total and phosphorylated p38, JNK, ERK and IKKα, IKKβ, IκBα were determined at least three times, and the representative data are shown. (C) Cytoplasmic and nuclear proteins were extracted and assayed by immunoblotting analysis. Expressions of β-actin and LaminB1 were shown as loading controls. Bands from (A–C) were analyzed by densitometry. Quantitative data are shown. *P<0.05 vs LPS control. (D) Nuclear proteins were extracted and assayed by EMSA. A 75-fold excess of unlabelled oligonucleotide probe and mutant probe were used as controls.

Mentions: In LPS signaling, activation of mitogen-activated protein kinases (MAPKs) and transcription factor NF-κB play essential roles in transcriptional induction of those genes involved in inflammation, such as iNOS, COX-2, TNF-α, IL-1β and IL-6 [17]. Here, we assessed the effects of DCO-6 on activation of MAPKs in RAW264.7 upon response to LPS. As shown in Fig. 3A, DCO-6 inhibited p38 MAPK phosphorylation induced by LPS in a concentration-dependent manner without any effect on total p38 MAPK expression. In contrast, DCO-6 did not affect phosphorylation of JNK, ERK induced by LPS. In spite of the failure in inhibition of phosphorylation of IKKα/β, DCO-6 slightly reduced phosphorylation of IκBα (Fig. 3B). Moreover, the nuclear localization of p65 subunit of NF-κB was inhibited by DCO-6, in line with the blockade of DNA binding activity of p65 in LPS-stimulated RAW264.7 cells (Fig. 3C and 3D).


A novel chromone derivative with anti-inflammatory property via inhibition of ROS-dependent activation of TRAF6-ASK1-p38 pathway.

Liu H, Xu R, Feng L, Guo W, Cao N, Qian C, Teng P, Wang L, Wu X, Sun Y, Li J, Shen Y, Xu Q - PLoS ONE (2012)

Effects of DCO-6 on the LPS-induced activation of MAPKs and NF-κB in RAW264.7 cells.Cells were treated with various concentrations of DCO-6 in the absence or presence of LPS for 6 h. (A–B) The protein levels of total and phosphorylated p38, JNK, ERK and IKKα, IKKβ, IκBα were determined at least three times, and the representative data are shown. (C) Cytoplasmic and nuclear proteins were extracted and assayed by immunoblotting analysis. Expressions of β-actin and LaminB1 were shown as loading controls. Bands from (A–C) were analyzed by densitometry. Quantitative data are shown. *P<0.05 vs LPS control. (D) Nuclear proteins were extracted and assayed by EMSA. A 75-fold excess of unlabelled oligonucleotide probe and mutant probe were used as controls.
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC3376149&req=5

pone-0037168-g003: Effects of DCO-6 on the LPS-induced activation of MAPKs and NF-κB in RAW264.7 cells.Cells were treated with various concentrations of DCO-6 in the absence or presence of LPS for 6 h. (A–B) The protein levels of total and phosphorylated p38, JNK, ERK and IKKα, IKKβ, IκBα were determined at least three times, and the representative data are shown. (C) Cytoplasmic and nuclear proteins were extracted and assayed by immunoblotting analysis. Expressions of β-actin and LaminB1 were shown as loading controls. Bands from (A–C) were analyzed by densitometry. Quantitative data are shown. *P<0.05 vs LPS control. (D) Nuclear proteins were extracted and assayed by EMSA. A 75-fold excess of unlabelled oligonucleotide probe and mutant probe were used as controls.
Mentions: In LPS signaling, activation of mitogen-activated protein kinases (MAPKs) and transcription factor NF-κB play essential roles in transcriptional induction of those genes involved in inflammation, such as iNOS, COX-2, TNF-α, IL-1β and IL-6 [17]. Here, we assessed the effects of DCO-6 on activation of MAPKs in RAW264.7 upon response to LPS. As shown in Fig. 3A, DCO-6 inhibited p38 MAPK phosphorylation induced by LPS in a concentration-dependent manner without any effect on total p38 MAPK expression. In contrast, DCO-6 did not affect phosphorylation of JNK, ERK induced by LPS. In spite of the failure in inhibition of phosphorylation of IKKα/β, DCO-6 slightly reduced phosphorylation of IκBα (Fig. 3B). Moreover, the nuclear localization of p65 subunit of NF-κB was inhibited by DCO-6, in line with the blockade of DNA binding activity of p65 in LPS-stimulated RAW264.7 cells (Fig. 3C and 3D).

Bottom Line: In the present study, we show that a novel chromone derivative, DCO-6, significantly reduced lipopolysaccharide (LPS)-induced production of nitric oxide, IL-1β and IL-6, decreased the levels of iNOS, IL-1β and IL-6 mRNA expression in both RAW264.7 cells and mouse primary peritoneal macrophages, and inhibited LPS-induced activation of p38 MAPK but not of JNK, ERK.LPS-induced production of intracellular reactive oxygen species (ROS) was remarkably impaired by DCO-6, which disrupted the formation of the TRAF6-ASK1 complex.Our results indicate that DCO-6 showed anti-inflammatory properties through inhibition of ROS-dependent activation of TRAF6-ASK1-p38 pathway.

View Article: PubMed Central - PubMed

Affiliation: State Key Laboratory of Pharmaceutical Biotechnology, School of Life Sciences, Nanjing University, Nanjing, China.

ABSTRACT
The p38 MAPK signaling pathway plays a pivotal role in inflammation. Targeting p38 MAPK may be a potential strategy for the treatment of inflammatory diseases. In the present study, we show that a novel chromone derivative, DCO-6, significantly reduced lipopolysaccharide (LPS)-induced production of nitric oxide, IL-1β and IL-6, decreased the levels of iNOS, IL-1β and IL-6 mRNA expression in both RAW264.7 cells and mouse primary peritoneal macrophages, and inhibited LPS-induced activation of p38 MAPK but not of JNK, ERK. Moreover, DCO-6 specifically inhibited TLR4-dependent p38 activation without directly inhibiting its kinase activity. LPS-induced production of intracellular reactive oxygen species (ROS) was remarkably impaired by DCO-6, which disrupted the formation of the TRAF6-ASK1 complex. Administering DCO-6 significantly protected mice from LPS-induced septic shock in parallel with the inhibition of p38 activation and ROS production. Our results indicate that DCO-6 showed anti-inflammatory properties through inhibition of ROS-dependent activation of TRAF6-ASK1-p38 pathway. Blockade of the upstream events required for p38 MAPK action by DCO-6 may provide a new therapeutic option in the treatment of inflammatory diseases.

Show MeSH
Related in: MedlinePlus