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Quercetin inhibits IL-1β-induced inflammation, hyaluronan production and adipogenesis in orbital fibroblasts from Graves' orbitopathy.

Yoon JS, Lee HJ, Choi SH, Chang EJ, Lee SY, Lee EJ - PLoS ONE (2011)

Bottom Line: Management of Graves' orbitopathy (GO) is challenging, as no reliable, specific, and safe medical therapeutic agents have yet been developed.Treatment with noncytotoxic doses of quercetin inhibited accumulation of intracytoplasmic lipid droplets and resulted in a dose-dependent decrease in expression of peroxisome proliferator-activated receptor γ, CCAAT/enhancer-binding protein (C/EBP) α, and C/EBPβ proteins.In conclusion, inhibition of inflammation, hyaluronan production, and adipogenesis by the natural plant product quercetin in vitro provides the basis for further study of its potential use in the treatment of GO.

View Article: PubMed Central - PubMed

Affiliation: Institute of Vision Research, Department of Ophthalmology, Yonsei University College of Medicine, Seoul, Korea.

ABSTRACT
Management of Graves' orbitopathy (GO) is challenging, as no reliable, specific, and safe medical therapeutic agents have yet been developed. We investigated the effect of quercetin in primary cultured orbital fibroblasts from GO, targeting pathways of inflammation, aberrant accumulation of extracellular matrix macromolecules, and adipose tissue expansion. Quercetin significantly attenuated intercellular adhesion molecule-1 (ICAM-1), interleukin (IL) -6, IL-8, and cyclooxygenase (COX) -2 mRNA expression, and inhibited IL-1β-induced increases in ICAM-1, IL-6, and IL-8 mRNA. Increased hyaluronan production induced by IL-1β or tumor necrosis factor-α was suppressed by quercetin in a dose- and time-dependent manner. Treatment with noncytotoxic doses of quercetin inhibited accumulation of intracytoplasmic lipid droplets and resulted in a dose-dependent decrease in expression of peroxisome proliferator-activated receptor γ, CCAAT/enhancer-binding protein (C/EBP) α, and C/EBPβ proteins. In conclusion, inhibition of inflammation, hyaluronan production, and adipogenesis by the natural plant product quercetin in vitro provides the basis for further study of its potential use in the treatment of GO.

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Effect of quercetin on NF-κB activation in GO orbital fibroblasts.(A) Cells were pretreated with quercetin for 24 h prior to IL-1β (10 ng/ml) stimulation for 16 h, and p65 NF-κB translocation was assayed by western blot analysis. (B) Results of assays measuring NF-κB activity with a NF-κB-dependent luciferase reporter construct in cells treated with quercetin (0, 50 or 100 µM, 24 h) prior to stimulation with IL-1β or TNF-α (10 ng/ml) for 16 h. (C) RT-PCR analysis of ICAM-1, IL-6, IL-8, and COX-2 expression in cells pretreated with NF-κB inhibitor SC-514 (100 µM) for 1 h and then stimulated with IL-1β (10 ng/ml). PCR bands measured by densitometry and normalized to GAPDH. *P<0.05 vs. cells stimulated with IL-1β or TNF-α alone.
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pone-0026261-g004: Effect of quercetin on NF-κB activation in GO orbital fibroblasts.(A) Cells were pretreated with quercetin for 24 h prior to IL-1β (10 ng/ml) stimulation for 16 h, and p65 NF-κB translocation was assayed by western blot analysis. (B) Results of assays measuring NF-κB activity with a NF-κB-dependent luciferase reporter construct in cells treated with quercetin (0, 50 or 100 µM, 24 h) prior to stimulation with IL-1β or TNF-α (10 ng/ml) for 16 h. (C) RT-PCR analysis of ICAM-1, IL-6, IL-8, and COX-2 expression in cells pretreated with NF-κB inhibitor SC-514 (100 µM) for 1 h and then stimulated with IL-1β (10 ng/ml). PCR bands measured by densitometry and normalized to GAPDH. *P<0.05 vs. cells stimulated with IL-1β or TNF-α alone.

Mentions: Because the NF-κB signaling pathway regulates the production of many cytokines, we investigated effects of IL-1β and quercetin on the nuclear translocation of active NF-κB in orbital fibroblasts from GO patients. As shown in Fig. 4A, stimulation of orbital fibroblasts with IL-1β induced nuclear translocation of p65 NF-κB, and quercetin dose-dependently inhibited this. We examined the effect of quercetin using an NF-κB-dependent luciferase reporter assay. Quercetin significantly reduced the IL-1β- or TNF-α-induced elevation of luciferase activity in a dose-dependent manner (Fig. 4B). To determine whether the IL-1β-stimulation of proinflammatory gene expression was mediated by an NF-κB-dependent pathway, SC-514, a selective IκB kinase-2 inhibitor, was tested. We found that preincubation with SC-514 (100 µM) for 1 h significantly decreased IL-1β-induced ICAM-1 and COX-2 gene expression, but the decreases in IL-6 and IL-8 mRNA were not significant (Fig. 4C), suggesting the presence of different activation mechanisms for these proinflammatory genes.


Quercetin inhibits IL-1β-induced inflammation, hyaluronan production and adipogenesis in orbital fibroblasts from Graves' orbitopathy.

Yoon JS, Lee HJ, Choi SH, Chang EJ, Lee SY, Lee EJ - PLoS ONE (2011)

Effect of quercetin on NF-κB activation in GO orbital fibroblasts.(A) Cells were pretreated with quercetin for 24 h prior to IL-1β (10 ng/ml) stimulation for 16 h, and p65 NF-κB translocation was assayed by western blot analysis. (B) Results of assays measuring NF-κB activity with a NF-κB-dependent luciferase reporter construct in cells treated with quercetin (0, 50 or 100 µM, 24 h) prior to stimulation with IL-1β or TNF-α (10 ng/ml) for 16 h. (C) RT-PCR analysis of ICAM-1, IL-6, IL-8, and COX-2 expression in cells pretreated with NF-κB inhibitor SC-514 (100 µM) for 1 h and then stimulated with IL-1β (10 ng/ml). PCR bands measured by densitometry and normalized to GAPDH. *P<0.05 vs. cells stimulated with IL-1β or TNF-α alone.
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Related In: Results  -  Collection

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getmorefigures.php?uid=PMC3198474&req=5

pone-0026261-g004: Effect of quercetin on NF-κB activation in GO orbital fibroblasts.(A) Cells were pretreated with quercetin for 24 h prior to IL-1β (10 ng/ml) stimulation for 16 h, and p65 NF-κB translocation was assayed by western blot analysis. (B) Results of assays measuring NF-κB activity with a NF-κB-dependent luciferase reporter construct in cells treated with quercetin (0, 50 or 100 µM, 24 h) prior to stimulation with IL-1β or TNF-α (10 ng/ml) for 16 h. (C) RT-PCR analysis of ICAM-1, IL-6, IL-8, and COX-2 expression in cells pretreated with NF-κB inhibitor SC-514 (100 µM) for 1 h and then stimulated with IL-1β (10 ng/ml). PCR bands measured by densitometry and normalized to GAPDH. *P<0.05 vs. cells stimulated with IL-1β or TNF-α alone.
Mentions: Because the NF-κB signaling pathway regulates the production of many cytokines, we investigated effects of IL-1β and quercetin on the nuclear translocation of active NF-κB in orbital fibroblasts from GO patients. As shown in Fig. 4A, stimulation of orbital fibroblasts with IL-1β induced nuclear translocation of p65 NF-κB, and quercetin dose-dependently inhibited this. We examined the effect of quercetin using an NF-κB-dependent luciferase reporter assay. Quercetin significantly reduced the IL-1β- or TNF-α-induced elevation of luciferase activity in a dose-dependent manner (Fig. 4B). To determine whether the IL-1β-stimulation of proinflammatory gene expression was mediated by an NF-κB-dependent pathway, SC-514, a selective IκB kinase-2 inhibitor, was tested. We found that preincubation with SC-514 (100 µM) for 1 h significantly decreased IL-1β-induced ICAM-1 and COX-2 gene expression, but the decreases in IL-6 and IL-8 mRNA were not significant (Fig. 4C), suggesting the presence of different activation mechanisms for these proinflammatory genes.

Bottom Line: Management of Graves' orbitopathy (GO) is challenging, as no reliable, specific, and safe medical therapeutic agents have yet been developed.Treatment with noncytotoxic doses of quercetin inhibited accumulation of intracytoplasmic lipid droplets and resulted in a dose-dependent decrease in expression of peroxisome proliferator-activated receptor γ, CCAAT/enhancer-binding protein (C/EBP) α, and C/EBPβ proteins.In conclusion, inhibition of inflammation, hyaluronan production, and adipogenesis by the natural plant product quercetin in vitro provides the basis for further study of its potential use in the treatment of GO.

View Article: PubMed Central - PubMed

Affiliation: Institute of Vision Research, Department of Ophthalmology, Yonsei University College of Medicine, Seoul, Korea.

ABSTRACT
Management of Graves' orbitopathy (GO) is challenging, as no reliable, specific, and safe medical therapeutic agents have yet been developed. We investigated the effect of quercetin in primary cultured orbital fibroblasts from GO, targeting pathways of inflammation, aberrant accumulation of extracellular matrix macromolecules, and adipose tissue expansion. Quercetin significantly attenuated intercellular adhesion molecule-1 (ICAM-1), interleukin (IL) -6, IL-8, and cyclooxygenase (COX) -2 mRNA expression, and inhibited IL-1β-induced increases in ICAM-1, IL-6, and IL-8 mRNA. Increased hyaluronan production induced by IL-1β or tumor necrosis factor-α was suppressed by quercetin in a dose- and time-dependent manner. Treatment with noncytotoxic doses of quercetin inhibited accumulation of intracytoplasmic lipid droplets and resulted in a dose-dependent decrease in expression of peroxisome proliferator-activated receptor γ, CCAAT/enhancer-binding protein (C/EBP) α, and C/EBPβ proteins. In conclusion, inhibition of inflammation, hyaluronan production, and adipogenesis by the natural plant product quercetin in vitro provides the basis for further study of its potential use in the treatment of GO.

Show MeSH
Related in: MedlinePlus