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Uteroglobin represses allergen-induced inflammatory response by blocking PGD2 receptor-mediated functions.

Mandal AK, Zhang Z, Ray R, Choi MS, Chowdhury B, Pattabiraman N, Mukherjee AB - J. Exp. Med. (2004)

Bottom Line: These effects are abrogated by recombinant UG treatment.Here we report that DP signaling is mediated via p38 mitogen-activated protein kinase, p44/42 mitogen-activated protein kinase, and protein kinase C pathways in a cell type-specific manner leading to nuclear factor-kappaB activation stimulating COX-2 gene expression.Further, we found that recombinant UG blocks DP-mediated nuclear factor-kappaB activation and suppresses COX-2 gene expression.

View Article: PubMed Central - PubMed

Affiliation: Bldg. 10, Rm. 9S241, National Institutes of Health, 9000 Rockville Pike, Bethesda, MD 20892, USA.

ABSTRACT
Uteroglobin (UG) is an antiinflammatory protein secreted by the epithelial lining of all organs communicating with the external environment. We reported previously that UG-knockout mice manifest exaggerated inflammatory response to allergen, characterized by increased eotaxin and Th2 cytokine gene expression, and eosinophil infiltration in the lungs. In this study, we uncovered that the airway epithelia of these mice also express high levels of cyclooxygenase (COX)-2, a key enzyme for the production of proinflammatory lipid mediators, and the bronchoalveolar lavage fluid (BALF) contain elevated levels of prostaglandin D2. These effects are abrogated by recombinant UG treatment. Although it has been reported that prostaglandin D2 mediates allergic inflammation via its receptor, DP, neither the molecular mechanism(s) of DP signaling nor the mechanism by which UG suppresses DP-mediated inflammatory response are clearly understood. Here we report that DP signaling is mediated via p38 mitogen-activated protein kinase, p44/42 mitogen-activated protein kinase, and protein kinase C pathways in a cell type-specific manner leading to nuclear factor-kappaB activation stimulating COX-2 gene expression. Further, we found that recombinant UG blocks DP-mediated nuclear factor-kappaB activation and suppresses COX-2 gene expression. We propose that UG is an essential component of a novel innate homeostatic mechanism in the mammalian airways to repress allergen-induced inflammatory responses.

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UG inhibits DP-mediated NF-κB activation and COX-2 expression. Expression of COX-2 mRNA in BSM 2146 (A) and NIH-3T3 cells (B). Cells were treated with PGD2 in the presence of rUG (0–200 nM) or MG (200 nM). Note that rUG inhibits DP-mediated COX-2 mRNA expression in a dose-dependent manner in both BSM-2146 (A) and NIH-3T3 (B), whereas MG has no such inhibitory effects (A and B, last lanes). EMSA using 32P-labeled double stranded NF-κB, NF-IL6, and AP-1 oligo probes in the absence and presence of respective double stranded competitor unlabeled oligo, demonstrating the effect of DP signaling on the activation of NF-κB in NIH-3T3 (C) cells. This activation of NF-κB by PGD2 is time dependent (D). EMSA demonstrating the effect of DP signaling on the activation of NF-κB in BSM-2146 (E) and NIH-3T3 (F) cells treated with PGD2 in the absence or presence of 150 nM purified rUG. Note rUG treatment before the addition of PGD2 inhibits NF-κB activation in both cell types.
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fig6: UG inhibits DP-mediated NF-κB activation and COX-2 expression. Expression of COX-2 mRNA in BSM 2146 (A) and NIH-3T3 cells (B). Cells were treated with PGD2 in the presence of rUG (0–200 nM) or MG (200 nM). Note that rUG inhibits DP-mediated COX-2 mRNA expression in a dose-dependent manner in both BSM-2146 (A) and NIH-3T3 (B), whereas MG has no such inhibitory effects (A and B, last lanes). EMSA using 32P-labeled double stranded NF-κB, NF-IL6, and AP-1 oligo probes in the absence and presence of respective double stranded competitor unlabeled oligo, demonstrating the effect of DP signaling on the activation of NF-κB in NIH-3T3 (C) cells. This activation of NF-κB by PGD2 is time dependent (D). EMSA demonstrating the effect of DP signaling on the activation of NF-κB in BSM-2146 (E) and NIH-3T3 (F) cells treated with PGD2 in the absence or presence of 150 nM purified rUG. Note rUG treatment before the addition of PGD2 inhibits NF-κB activation in both cell types.

Mentions: We have shown that UG counteracts allergen-induced COX-2 gene expression in OVA-challenged allergic model of UG-KO mice (see the UG Inhibits Allergen-induced Stimulation…). Since OVA induces elevated levels of PGD2 in BALF, we determined if UG inhibits PGD2-mediated stimulation of COX-2 expression in vitro. We treated BSM-2146 and NIH-3T3 cells with PGD2 in the presence and absence of varying concentrations of UG and determined COX-2 mRNA expression by Northern blot analysis. We found that in both BSM-2146 (Fig. 6 A) and NIH-3T3 (Fig. 6 B) cells UG inhibits PGD2-induced COX-2 mRNA expression in a dose-dependent manner. Myoglobin (MG), a nonspecific control does not inhibit PGD2-stimulated COX-2 expression. Together, these results suggest that UG specifically inhibits PGD2-mediated COX-2 expression.


Uteroglobin represses allergen-induced inflammatory response by blocking PGD2 receptor-mediated functions.

Mandal AK, Zhang Z, Ray R, Choi MS, Chowdhury B, Pattabiraman N, Mukherjee AB - J. Exp. Med. (2004)

UG inhibits DP-mediated NF-κB activation and COX-2 expression. Expression of COX-2 mRNA in BSM 2146 (A) and NIH-3T3 cells (B). Cells were treated with PGD2 in the presence of rUG (0–200 nM) or MG (200 nM). Note that rUG inhibits DP-mediated COX-2 mRNA expression in a dose-dependent manner in both BSM-2146 (A) and NIH-3T3 (B), whereas MG has no such inhibitory effects (A and B, last lanes). EMSA using 32P-labeled double stranded NF-κB, NF-IL6, and AP-1 oligo probes in the absence and presence of respective double stranded competitor unlabeled oligo, demonstrating the effect of DP signaling on the activation of NF-κB in NIH-3T3 (C) cells. This activation of NF-κB by PGD2 is time dependent (D). EMSA demonstrating the effect of DP signaling on the activation of NF-κB in BSM-2146 (E) and NIH-3T3 (F) cells treated with PGD2 in the absence or presence of 150 nM purified rUG. Note rUG treatment before the addition of PGD2 inhibits NF-κB activation in both cell types.
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Related In: Results  -  Collection

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getmorefigures.php?uid=PMC2211805&req=5

fig6: UG inhibits DP-mediated NF-κB activation and COX-2 expression. Expression of COX-2 mRNA in BSM 2146 (A) and NIH-3T3 cells (B). Cells were treated with PGD2 in the presence of rUG (0–200 nM) or MG (200 nM). Note that rUG inhibits DP-mediated COX-2 mRNA expression in a dose-dependent manner in both BSM-2146 (A) and NIH-3T3 (B), whereas MG has no such inhibitory effects (A and B, last lanes). EMSA using 32P-labeled double stranded NF-κB, NF-IL6, and AP-1 oligo probes in the absence and presence of respective double stranded competitor unlabeled oligo, demonstrating the effect of DP signaling on the activation of NF-κB in NIH-3T3 (C) cells. This activation of NF-κB by PGD2 is time dependent (D). EMSA demonstrating the effect of DP signaling on the activation of NF-κB in BSM-2146 (E) and NIH-3T3 (F) cells treated with PGD2 in the absence or presence of 150 nM purified rUG. Note rUG treatment before the addition of PGD2 inhibits NF-κB activation in both cell types.
Mentions: We have shown that UG counteracts allergen-induced COX-2 gene expression in OVA-challenged allergic model of UG-KO mice (see the UG Inhibits Allergen-induced Stimulation…). Since OVA induces elevated levels of PGD2 in BALF, we determined if UG inhibits PGD2-mediated stimulation of COX-2 expression in vitro. We treated BSM-2146 and NIH-3T3 cells with PGD2 in the presence and absence of varying concentrations of UG and determined COX-2 mRNA expression by Northern blot analysis. We found that in both BSM-2146 (Fig. 6 A) and NIH-3T3 (Fig. 6 B) cells UG inhibits PGD2-induced COX-2 mRNA expression in a dose-dependent manner. Myoglobin (MG), a nonspecific control does not inhibit PGD2-stimulated COX-2 expression. Together, these results suggest that UG specifically inhibits PGD2-mediated COX-2 expression.

Bottom Line: These effects are abrogated by recombinant UG treatment.Here we report that DP signaling is mediated via p38 mitogen-activated protein kinase, p44/42 mitogen-activated protein kinase, and protein kinase C pathways in a cell type-specific manner leading to nuclear factor-kappaB activation stimulating COX-2 gene expression.Further, we found that recombinant UG blocks DP-mediated nuclear factor-kappaB activation and suppresses COX-2 gene expression.

View Article: PubMed Central - PubMed

Affiliation: Bldg. 10, Rm. 9S241, National Institutes of Health, 9000 Rockville Pike, Bethesda, MD 20892, USA.

ABSTRACT
Uteroglobin (UG) is an antiinflammatory protein secreted by the epithelial lining of all organs communicating with the external environment. We reported previously that UG-knockout mice manifest exaggerated inflammatory response to allergen, characterized by increased eotaxin and Th2 cytokine gene expression, and eosinophil infiltration in the lungs. In this study, we uncovered that the airway epithelia of these mice also express high levels of cyclooxygenase (COX)-2, a key enzyme for the production of proinflammatory lipid mediators, and the bronchoalveolar lavage fluid (BALF) contain elevated levels of prostaglandin D2. These effects are abrogated by recombinant UG treatment. Although it has been reported that prostaglandin D2 mediates allergic inflammation via its receptor, DP, neither the molecular mechanism(s) of DP signaling nor the mechanism by which UG suppresses DP-mediated inflammatory response are clearly understood. Here we report that DP signaling is mediated via p38 mitogen-activated protein kinase, p44/42 mitogen-activated protein kinase, and protein kinase C pathways in a cell type-specific manner leading to nuclear factor-kappaB activation stimulating COX-2 gene expression. Further, we found that recombinant UG blocks DP-mediated nuclear factor-kappaB activation and suppresses COX-2 gene expression. We propose that UG is an essential component of a novel innate homeostatic mechanism in the mammalian airways to repress allergen-induced inflammatory responses.

Show MeSH
Related in: MedlinePlus