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Imperatorin Suppresses Degranulation and Eicosanoid Generation in Activated Bone Marrow-Derived Mast Cells.

Jeong KT, Lee E, Park NY, Kim SG, Park HH, Lee J, Lee YJ, Lee E - Biomol Ther (Seoul) (2015)

Bottom Line: To elucidate the molecular mechanism involved in this process, we investigated the effect of imperatorin on intracellular signaling in BMMC.Biochemical analyses of the IgE/Ag-mediated signaling pathway demonstrated that imperatorin dramatically attenuated degranulation and the production of 5-lipoxygenase-dependent LTC4 and cyclooxygenase-2-dependent PGD2 through the inhibition of intracellular calcium influx/phospholipase Cγ1, cytosolic phospholipase A2/mitogen-activated protein kinases and/or nuclear factor-κB pathways in BMMC.These results suggest that the effects of imperatorin on inhibition of degranulation and eicosanoid generation through the suppression of multiple steps of IgE/Ag-mediated signaling pathways would be beneficial for the prevention of allergic inflammation.

View Article: PubMed Central - PubMed

Affiliation: Research and Development Division, Korea Promotion Institute for Traditional Medicine Industry, Gyeongsan 712-210.

ABSTRACT
Imperatorin has been known to exert many biological functions including anti-inflammatory activity. In this study, we investigated the inhibitory effects of imperatorin on the production of inflammatory mediators in mouse bone marrow-derived mast cells (BMMC). Imperatorin inhibited degranulation and the generation of eicosanoids (leukotriene C4 (LTC4) and prostaglandin D2 (PGD2)) in IgE/antigen (Ag)-stimulated BMMC. To elucidate the molecular mechanism involved in this process, we investigated the effect of imperatorin on intracellular signaling in BMMC. Biochemical analyses of the IgE/Ag-mediated signaling pathway demonstrated that imperatorin dramatically attenuated degranulation and the production of 5-lipoxygenase-dependent LTC4 and cyclooxygenase-2-dependent PGD2 through the inhibition of intracellular calcium influx/phospholipase Cγ1, cytosolic phospholipase A2/mitogen-activated protein kinases and/or nuclear factor-κB pathways in BMMC. These results suggest that the effects of imperatorin on inhibition of degranulation and eicosanoid generation through the suppression of multiple steps of IgE/Ag-mediated signaling pathways would be beneficial for the prevention of allergic inflammation.

No MeSH data available.


Related in: MedlinePlus

Effect of imperatorin on LTC4 generation (A), 5-LO (B), and cPLA2 phosphorylation (C). BMMC sensitized overnight with IgE were pre-incubated with the indicated concentrations of imperatorin for 1 h and stimulated with DNP-HAS (Ag, 100 mg/ml) for 15 min. LTC4 release into the supernatant was determined using an enzyme immunoassay kit (A) and the cells were used for Western blot analysis to detect the cytosolic and nuclear fraction of 5-LO (B), and total cell lysates for cPLA2 (C). The values are expressed as the means ± S.E.M. of three different samples. *p<0.05, **p<0.01, ***p<0.001, significantly different from the control as determined by one-way ANOVA.
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f2-bt-23-421: Effect of imperatorin on LTC4 generation (A), 5-LO (B), and cPLA2 phosphorylation (C). BMMC sensitized overnight with IgE were pre-incubated with the indicated concentrations of imperatorin for 1 h and stimulated with DNP-HAS (Ag, 100 mg/ml) for 15 min. LTC4 release into the supernatant was determined using an enzyme immunoassay kit (A) and the cells were used for Western blot analysis to detect the cytosolic and nuclear fraction of 5-LO (B), and total cell lysates for cPLA2 (C). The values are expressed as the means ± S.E.M. of three different samples. *p<0.05, **p<0.01, ***p<0.001, significantly different from the control as determined by one-way ANOVA.

Mentions: The lipid mediator such as LT can initiate and amplify inflammatory responses (Harizi et al., 2008). In order to determine whether imperatorin inhibits LTC4 generation, BMMC were pre-treated with different concentrations of imperatorin for 1 h and then stimulated with Ag for 15 min. As shown in Fig. 2A, we observed that the LTC4 level was significantly increased to 32 ng/ml, but imperatorin consistently inhibited LTC4 generation in a dose-dependent manner, with an IC50 value of 7.6 μg/ml. LTC4 generation is regulated by the liberation of AA from membrane phopholipids by cPLA2 and 5-LO, which translocate from the cytosol to the nuclear membrane in the presence of 5-LO activating protein in response to the increased intracellular Ca2+ level (Fischer et al., 2005; Flamand et al., 2006). In this study, we investigated the effect of imperatorin on phosphorylation and translocation of cPLA2 and 5-LO. As shown in Fig. 2B, 5-LO was mainly localized in the cytosol in unstimulated BMMC, but it was translocated to the nuclear fraction by Ag treatment. However, imperatorin inhibited the translocation of 5-LO. The p-cPLA2 level was dramatically increased in Ag-activated BMMC but it was suppressed by imperatorin treatment in a dose-dependent manner (Fig. 2C). These results indicate that imperatorin suppressed LTC4 generation by inhibiting phosphorylation and translocation of cPLA2 and 5-LO.


Imperatorin Suppresses Degranulation and Eicosanoid Generation in Activated Bone Marrow-Derived Mast Cells.

Jeong KT, Lee E, Park NY, Kim SG, Park HH, Lee J, Lee YJ, Lee E - Biomol Ther (Seoul) (2015)

Effect of imperatorin on LTC4 generation (A), 5-LO (B), and cPLA2 phosphorylation (C). BMMC sensitized overnight with IgE were pre-incubated with the indicated concentrations of imperatorin for 1 h and stimulated with DNP-HAS (Ag, 100 mg/ml) for 15 min. LTC4 release into the supernatant was determined using an enzyme immunoassay kit (A) and the cells were used for Western blot analysis to detect the cytosolic and nuclear fraction of 5-LO (B), and total cell lysates for cPLA2 (C). The values are expressed as the means ± S.E.M. of three different samples. *p<0.05, **p<0.01, ***p<0.001, significantly different from the control as determined by one-way ANOVA.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4556201&req=5

f2-bt-23-421: Effect of imperatorin on LTC4 generation (A), 5-LO (B), and cPLA2 phosphorylation (C). BMMC sensitized overnight with IgE were pre-incubated with the indicated concentrations of imperatorin for 1 h and stimulated with DNP-HAS (Ag, 100 mg/ml) for 15 min. LTC4 release into the supernatant was determined using an enzyme immunoassay kit (A) and the cells were used for Western blot analysis to detect the cytosolic and nuclear fraction of 5-LO (B), and total cell lysates for cPLA2 (C). The values are expressed as the means ± S.E.M. of three different samples. *p<0.05, **p<0.01, ***p<0.001, significantly different from the control as determined by one-way ANOVA.
Mentions: The lipid mediator such as LT can initiate and amplify inflammatory responses (Harizi et al., 2008). In order to determine whether imperatorin inhibits LTC4 generation, BMMC were pre-treated with different concentrations of imperatorin for 1 h and then stimulated with Ag for 15 min. As shown in Fig. 2A, we observed that the LTC4 level was significantly increased to 32 ng/ml, but imperatorin consistently inhibited LTC4 generation in a dose-dependent manner, with an IC50 value of 7.6 μg/ml. LTC4 generation is regulated by the liberation of AA from membrane phopholipids by cPLA2 and 5-LO, which translocate from the cytosol to the nuclear membrane in the presence of 5-LO activating protein in response to the increased intracellular Ca2+ level (Fischer et al., 2005; Flamand et al., 2006). In this study, we investigated the effect of imperatorin on phosphorylation and translocation of cPLA2 and 5-LO. As shown in Fig. 2B, 5-LO was mainly localized in the cytosol in unstimulated BMMC, but it was translocated to the nuclear fraction by Ag treatment. However, imperatorin inhibited the translocation of 5-LO. The p-cPLA2 level was dramatically increased in Ag-activated BMMC but it was suppressed by imperatorin treatment in a dose-dependent manner (Fig. 2C). These results indicate that imperatorin suppressed LTC4 generation by inhibiting phosphorylation and translocation of cPLA2 and 5-LO.

Bottom Line: To elucidate the molecular mechanism involved in this process, we investigated the effect of imperatorin on intracellular signaling in BMMC.Biochemical analyses of the IgE/Ag-mediated signaling pathway demonstrated that imperatorin dramatically attenuated degranulation and the production of 5-lipoxygenase-dependent LTC4 and cyclooxygenase-2-dependent PGD2 through the inhibition of intracellular calcium influx/phospholipase Cγ1, cytosolic phospholipase A2/mitogen-activated protein kinases and/or nuclear factor-κB pathways in BMMC.These results suggest that the effects of imperatorin on inhibition of degranulation and eicosanoid generation through the suppression of multiple steps of IgE/Ag-mediated signaling pathways would be beneficial for the prevention of allergic inflammation.

View Article: PubMed Central - PubMed

Affiliation: Research and Development Division, Korea Promotion Institute for Traditional Medicine Industry, Gyeongsan 712-210.

ABSTRACT
Imperatorin has been known to exert many biological functions including anti-inflammatory activity. In this study, we investigated the inhibitory effects of imperatorin on the production of inflammatory mediators in mouse bone marrow-derived mast cells (BMMC). Imperatorin inhibited degranulation and the generation of eicosanoids (leukotriene C4 (LTC4) and prostaglandin D2 (PGD2)) in IgE/antigen (Ag)-stimulated BMMC. To elucidate the molecular mechanism involved in this process, we investigated the effect of imperatorin on intracellular signaling in BMMC. Biochemical analyses of the IgE/Ag-mediated signaling pathway demonstrated that imperatorin dramatically attenuated degranulation and the production of 5-lipoxygenase-dependent LTC4 and cyclooxygenase-2-dependent PGD2 through the inhibition of intracellular calcium influx/phospholipase Cγ1, cytosolic phospholipase A2/mitogen-activated protein kinases and/or nuclear factor-κB pathways in BMMC. These results suggest that the effects of imperatorin on inhibition of degranulation and eicosanoid generation through the suppression of multiple steps of IgE/Ag-mediated signaling pathways would be beneficial for the prevention of allergic inflammation.

No MeSH data available.


Related in: MedlinePlus