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Activation of peroxisome proliferator-activated receptor γ by rosiglitazone inhibits lipopolysaccharide-induced release of high mobility group box 1.

Hwang JS, Kang ES, Ham SA, Yoo T, Lee H, Paek KS, Park C, Kim JH, Lim DS, Seo HG - Mediators Inflamm. (2012)

Bottom Line: Among the ligands of PPAR, the effect of rosiglitazone, a specific ligand for PPARγ, was superior in the inhibition of HMGB1 release induced by LPS.Notably, the administration of rosiglitazone to mice improved survival rates in an LPS-induced animal model of endotoxemia, where reduced levels of circulating HMGB1 were demonstrated.Taken together, these results suggest that PPARs play an important role in the cellular response to inflammation by inhibiting HMGB1 release.

View Article: PubMed Central - PubMed

Affiliation: Department of Animal Biotechnology, Konkuk University, Seoul, Republic of Korea.

ABSTRACT
Peroxisome proliferator-activated receptors (PPARs) are shown to modulate the pathological status of sepsis by regulating the release of high mobility group box 1 (HMGB1), a well-known late proinflammatory mediator of sepsis. Ligand-activated PPARs markedly inhibited lipopolysaccharide- (LPS) induced release of HMGB1 in RAW 264.7 cells. Among the ligands of PPAR, the effect of rosiglitazone, a specific ligand for PPARγ, was superior in the inhibition of HMGB1 release induced by LPS. This effect was observed in cells that received rosiglitazone before LPS or after LPS treatment, indicating that rosiglitazone is effective in both treatment and prevention. Ablation of PPARγ with small interfering RNA or GW9662-mediated inhibition of PPARγ abolished the effect of rosiglitazone on HMGB1 release. Furthermore, the overexpression of PPARγ markedly potentiated the inhibitory effect of rosiglitazone on HMGB1 release. In addition, rosiglitazone inhibited LPS-induced expression of Toll-like receptor 4 signal molecules, suggesting a possible mechanism by which rosiglitazone modulates HMGB1 release. Notably, the administration of rosiglitazone to mice improved survival rates in an LPS-induced animal model of endotoxemia, where reduced levels of circulating HMGB1 were demonstrated. Taken together, these results suggest that PPARs play an important role in the cellular response to inflammation by inhibiting HMGB1 release.

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Rosiglitazone inhibits LPS-induced TLR4 signal pathway in RAW 264.7 cells. (a) Cells incubated with serum-free medium for 24 h were treated with LPS in the presence or absence of rosiglitazone for 6 h. The mRNA levels of indicated genes were determined by real-time PCR using SYBR Green. GAPDH was used as an internal standard. (b) Cells were incubated in serum-free medium for 24 h and then stimulated with LPS in the presence or absence of rosiglitazone for 9 h. Total protein was extracted, fractionated by electrophoresis, and immunoblotted with the indicated antibodies. (c) Cells incubated with serum-free medium for 24 h were treated with LPS in the presence or absence of rosiglitazone for 1 h. An aliquot of protein was immunoblotted with phospho-IκBα (p-IκBα) and β-actin antibodies. The results are expressed as the means ± S.E. (n = 3). **P < 0.01 compared to untreated group; #P < 0.05, ##P < 0.01 compared to LPS-treated group.
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fig5: Rosiglitazone inhibits LPS-induced TLR4 signal pathway in RAW 264.7 cells. (a) Cells incubated with serum-free medium for 24 h were treated with LPS in the presence or absence of rosiglitazone for 6 h. The mRNA levels of indicated genes were determined by real-time PCR using SYBR Green. GAPDH was used as an internal standard. (b) Cells were incubated in serum-free medium for 24 h and then stimulated with LPS in the presence or absence of rosiglitazone for 9 h. Total protein was extracted, fractionated by electrophoresis, and immunoblotted with the indicated antibodies. (c) Cells incubated with serum-free medium for 24 h were treated with LPS in the presence or absence of rosiglitazone for 1 h. An aliquot of protein was immunoblotted with phospho-IκBα (p-IκBα) and β-actin antibodies. The results are expressed as the means ± S.E. (n = 3). **P < 0.01 compared to untreated group; #P < 0.05, ##P < 0.01 compared to LPS-treated group.

Mentions: Since TLR4 is involved in the regulation of LPS-induced HMGB1 release [22, 23], we examined whether rosiglitazone affects TLR4 signal pathway in LPS-treated RAW 264.7 cells. Expression of MyD88 and TRIF, key adaptor molecules of TLR4, was increased in RAW264.7 cells treated with LPS for 6 h, whereas simultaneous administration of rosiglitazone significantly reduced the levels of MyD88 and TRIF (Figures 5(a) and 5(b)). In addition, rosiglitazone also significantly inhibited the LPS-induced phosphorylation of IκBα (Figure 5(c)), indicating that the activation of PPARγ by rosiglitazone modulates TLR4 signal pathway by inhibiting the LPS-induced expression of MyD88/TRIF, and consequent blocking its effector NF-κB.


Activation of peroxisome proliferator-activated receptor γ by rosiglitazone inhibits lipopolysaccharide-induced release of high mobility group box 1.

Hwang JS, Kang ES, Ham SA, Yoo T, Lee H, Paek KS, Park C, Kim JH, Lim DS, Seo HG - Mediators Inflamm. (2012)

Rosiglitazone inhibits LPS-induced TLR4 signal pathway in RAW 264.7 cells. (a) Cells incubated with serum-free medium for 24 h were treated with LPS in the presence or absence of rosiglitazone for 6 h. The mRNA levels of indicated genes were determined by real-time PCR using SYBR Green. GAPDH was used as an internal standard. (b) Cells were incubated in serum-free medium for 24 h and then stimulated with LPS in the presence or absence of rosiglitazone for 9 h. Total protein was extracted, fractionated by electrophoresis, and immunoblotted with the indicated antibodies. (c) Cells incubated with serum-free medium for 24 h were treated with LPS in the presence or absence of rosiglitazone for 1 h. An aliquot of protein was immunoblotted with phospho-IκBα (p-IκBα) and β-actin antibodies. The results are expressed as the means ± S.E. (n = 3). **P < 0.01 compared to untreated group; #P < 0.05, ##P < 0.01 compared to LPS-treated group.
© Copyright Policy - open-access
Related In: Results  -  Collection

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getmorefigures.php?uid=PMC3539392&req=5

fig5: Rosiglitazone inhibits LPS-induced TLR4 signal pathway in RAW 264.7 cells. (a) Cells incubated with serum-free medium for 24 h were treated with LPS in the presence or absence of rosiglitazone for 6 h. The mRNA levels of indicated genes were determined by real-time PCR using SYBR Green. GAPDH was used as an internal standard. (b) Cells were incubated in serum-free medium for 24 h and then stimulated with LPS in the presence or absence of rosiglitazone for 9 h. Total protein was extracted, fractionated by electrophoresis, and immunoblotted with the indicated antibodies. (c) Cells incubated with serum-free medium for 24 h were treated with LPS in the presence or absence of rosiglitazone for 1 h. An aliquot of protein was immunoblotted with phospho-IκBα (p-IκBα) and β-actin antibodies. The results are expressed as the means ± S.E. (n = 3). **P < 0.01 compared to untreated group; #P < 0.05, ##P < 0.01 compared to LPS-treated group.
Mentions: Since TLR4 is involved in the regulation of LPS-induced HMGB1 release [22, 23], we examined whether rosiglitazone affects TLR4 signal pathway in LPS-treated RAW 264.7 cells. Expression of MyD88 and TRIF, key adaptor molecules of TLR4, was increased in RAW264.7 cells treated with LPS for 6 h, whereas simultaneous administration of rosiglitazone significantly reduced the levels of MyD88 and TRIF (Figures 5(a) and 5(b)). In addition, rosiglitazone also significantly inhibited the LPS-induced phosphorylation of IκBα (Figure 5(c)), indicating that the activation of PPARγ by rosiglitazone modulates TLR4 signal pathway by inhibiting the LPS-induced expression of MyD88/TRIF, and consequent blocking its effector NF-κB.

Bottom Line: Among the ligands of PPAR, the effect of rosiglitazone, a specific ligand for PPARγ, was superior in the inhibition of HMGB1 release induced by LPS.Notably, the administration of rosiglitazone to mice improved survival rates in an LPS-induced animal model of endotoxemia, where reduced levels of circulating HMGB1 were demonstrated.Taken together, these results suggest that PPARs play an important role in the cellular response to inflammation by inhibiting HMGB1 release.

View Article: PubMed Central - PubMed

Affiliation: Department of Animal Biotechnology, Konkuk University, Seoul, Republic of Korea.

ABSTRACT
Peroxisome proliferator-activated receptors (PPARs) are shown to modulate the pathological status of sepsis by regulating the release of high mobility group box 1 (HMGB1), a well-known late proinflammatory mediator of sepsis. Ligand-activated PPARs markedly inhibited lipopolysaccharide- (LPS) induced release of HMGB1 in RAW 264.7 cells. Among the ligands of PPAR, the effect of rosiglitazone, a specific ligand for PPARγ, was superior in the inhibition of HMGB1 release induced by LPS. This effect was observed in cells that received rosiglitazone before LPS or after LPS treatment, indicating that rosiglitazone is effective in both treatment and prevention. Ablation of PPARγ with small interfering RNA or GW9662-mediated inhibition of PPARγ abolished the effect of rosiglitazone on HMGB1 release. Furthermore, the overexpression of PPARγ markedly potentiated the inhibitory effect of rosiglitazone on HMGB1 release. In addition, rosiglitazone inhibited LPS-induced expression of Toll-like receptor 4 signal molecules, suggesting a possible mechanism by which rosiglitazone modulates HMGB1 release. Notably, the administration of rosiglitazone to mice improved survival rates in an LPS-induced animal model of endotoxemia, where reduced levels of circulating HMGB1 were demonstrated. Taken together, these results suggest that PPARs play an important role in the cellular response to inflammation by inhibiting HMGB1 release.

Show MeSH
Related in: MedlinePlus