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Lymphotoxin β receptor signaling induces IL-8 production in human bronchial epithelial cells.

Mikami Y, Matsuzaki H, Horie M, Noguchi S, Jo T, Narumoto O, Kohyama T, Takizawa H, Nagase T, Yamauchi Y - PLoS ONE (2014)

Bottom Line: LIGHT also induced luciferase activity of NF-κB response element, but not of activator protein-1 or serum response element.Specific inhibitors of phosphorylation of extracellular signal-regulated kinase (Erk) and that of inhibitor κB attenuated IL-8 production, suggesting that LIGHT-LTβR signaling induces IL-8 production via the Erk and NF-κB pathways.LIGHT, via LTβR signaling, may contribute to exacerbation of airway neutrophilic inflammation through cytokine and chemokine production by bronchial epithelial cells.

View Article: PubMed Central - PubMed

Affiliation: Department of Respiratory Medicine, Graduate School of Medicine, The University of Tokyo, Tokyo, Japan.

ABSTRACT
Asthma-related mortality has been decreasing due to inhaled corticosteroid use, but severe asthma remains a major clinical problem. One characteristic of severe asthma is resistance to steroid therapy, which is related to neutrophilic inflammation. Recently, the tumor necrosis factor superfamily member (TNFSF) 14/LIGHT has been recognized as a key mediator in severe asthmatic airway inflammation. However, the profiles and intracellular mechanisms of cytokine/chemokine production induced in cells by LIGHT are poorly understood. We aimed to elucidate the molecular mechanism of LIGHT-induced cytokine/chemokine production by bronchial epithelial cells. Human bronchial epithelial cells express lymphotoxin β receptor (LTβR), but not herpesvirus entry mediator, which are receptors for LIGHT. LIGHT induced various cytokines/chemokines, such as interleukin (IL)-6, oncostatin M, monocyte chemotactic protein-1, growth-regulated protein α and IL-8. Specific siRNA for LTβR attenuated IL-6 and IL-8 production by BEAS-2B and normal human bronchial epithelial cells. LIGHT activated intracellular signaling, such as mitogen-activated protein kinase and nuclear factor-κB (NF-κB) signaling. LIGHT also induced luciferase activity of NF-κB response element, but not of activator protein-1 or serum response element. Specific inhibitors of phosphorylation of extracellular signal-regulated kinase (Erk) and that of inhibitor κB attenuated IL-8 production, suggesting that LIGHT-LTβR signaling induces IL-8 production via the Erk and NF-κB pathways. LIGHT, via LTβR signaling, may contribute to exacerbation of airway neutrophilic inflammation through cytokine and chemokine production by bronchial epithelial cells.

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Erk1/2 signaling and NF-κB release.(A) To evaluate the relationship between Erk1/2 signaling and NF-κB release, BEAS-2B cells were pretreated with U0126 (10 µM) 1 h before stimulation with LIGHT. U0126 did not inhibit IκBα phosphorylation or NF-κB translocation from the cytoplasm to the nucleus. (B) We evaluated the effect of LTβR knockdown on Erk1/2 signaling and NF-κB release. BEAS-2B cells were transfected with negative control siRNA (NC siRNA) or LTβR siRNA#2, stimulated with LIGHT (50 ng/ml) and analyzed by western blotting. The cells that were transfected with LTβR siRNA showed attenuation of Erk1/2 phosphorylation and NF-κB translocation induced by LIGHT.
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pone-0114791-g007: Erk1/2 signaling and NF-κB release.(A) To evaluate the relationship between Erk1/2 signaling and NF-κB release, BEAS-2B cells were pretreated with U0126 (10 µM) 1 h before stimulation with LIGHT. U0126 did not inhibit IκBα phosphorylation or NF-κB translocation from the cytoplasm to the nucleus. (B) We evaluated the effect of LTβR knockdown on Erk1/2 signaling and NF-κB release. BEAS-2B cells were transfected with negative control siRNA (NC siRNA) or LTβR siRNA#2, stimulated with LIGHT (50 ng/ml) and analyzed by western blotting. The cells that were transfected with LTβR siRNA showed attenuation of Erk1/2 phosphorylation and NF-κB translocation induced by LIGHT.

Mentions: Based on the above results, we examined whether Erk1/2 signaling could induce NF-κB for IL-8 production. U0126 did not inhibit IκBα phosphorylation or NF-κB translocation to the nucleus (Fig. 7A). In contrast, LTβR siRNA attenuated Erk1/2 phosphorylation and NF-κB translocation (Fig. 7B). These results indicate that Erk1/2 signaling and NF-κB signaling are down-stream of LTβR signaling, but NF-κB signaling is not directly down-stream of Erk1/2 signaling. We also performed luciferase reporter assay to evaluate whether LTβR signaling could activate transcription factor response elements. As shown in Fig. 8, LIGHT induced luciferase activity of NF-κB response element, but not AP-1 or SRE. U0126 partially attenuated the luciferase activity of NF-κB response element induced by LIGHT, indicating that Erk1/2 signaling is partially involved in induction of NF-κB expression.


Lymphotoxin β receptor signaling induces IL-8 production in human bronchial epithelial cells.

Mikami Y, Matsuzaki H, Horie M, Noguchi S, Jo T, Narumoto O, Kohyama T, Takizawa H, Nagase T, Yamauchi Y - PLoS ONE (2014)

Erk1/2 signaling and NF-κB release.(A) To evaluate the relationship between Erk1/2 signaling and NF-κB release, BEAS-2B cells were pretreated with U0126 (10 µM) 1 h before stimulation with LIGHT. U0126 did not inhibit IκBα phosphorylation or NF-κB translocation from the cytoplasm to the nucleus. (B) We evaluated the effect of LTβR knockdown on Erk1/2 signaling and NF-κB release. BEAS-2B cells were transfected with negative control siRNA (NC siRNA) or LTβR siRNA#2, stimulated with LIGHT (50 ng/ml) and analyzed by western blotting. The cells that were transfected with LTβR siRNA showed attenuation of Erk1/2 phosphorylation and NF-κB translocation induced by LIGHT.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4263477&req=5

pone-0114791-g007: Erk1/2 signaling and NF-κB release.(A) To evaluate the relationship between Erk1/2 signaling and NF-κB release, BEAS-2B cells were pretreated with U0126 (10 µM) 1 h before stimulation with LIGHT. U0126 did not inhibit IκBα phosphorylation or NF-κB translocation from the cytoplasm to the nucleus. (B) We evaluated the effect of LTβR knockdown on Erk1/2 signaling and NF-κB release. BEAS-2B cells were transfected with negative control siRNA (NC siRNA) or LTβR siRNA#2, stimulated with LIGHT (50 ng/ml) and analyzed by western blotting. The cells that were transfected with LTβR siRNA showed attenuation of Erk1/2 phosphorylation and NF-κB translocation induced by LIGHT.
Mentions: Based on the above results, we examined whether Erk1/2 signaling could induce NF-κB for IL-8 production. U0126 did not inhibit IκBα phosphorylation or NF-κB translocation to the nucleus (Fig. 7A). In contrast, LTβR siRNA attenuated Erk1/2 phosphorylation and NF-κB translocation (Fig. 7B). These results indicate that Erk1/2 signaling and NF-κB signaling are down-stream of LTβR signaling, but NF-κB signaling is not directly down-stream of Erk1/2 signaling. We also performed luciferase reporter assay to evaluate whether LTβR signaling could activate transcription factor response elements. As shown in Fig. 8, LIGHT induced luciferase activity of NF-κB response element, but not AP-1 or SRE. U0126 partially attenuated the luciferase activity of NF-κB response element induced by LIGHT, indicating that Erk1/2 signaling is partially involved in induction of NF-κB expression.

Bottom Line: LIGHT also induced luciferase activity of NF-κB response element, but not of activator protein-1 or serum response element.Specific inhibitors of phosphorylation of extracellular signal-regulated kinase (Erk) and that of inhibitor κB attenuated IL-8 production, suggesting that LIGHT-LTβR signaling induces IL-8 production via the Erk and NF-κB pathways.LIGHT, via LTβR signaling, may contribute to exacerbation of airway neutrophilic inflammation through cytokine and chemokine production by bronchial epithelial cells.

View Article: PubMed Central - PubMed

Affiliation: Department of Respiratory Medicine, Graduate School of Medicine, The University of Tokyo, Tokyo, Japan.

ABSTRACT
Asthma-related mortality has been decreasing due to inhaled corticosteroid use, but severe asthma remains a major clinical problem. One characteristic of severe asthma is resistance to steroid therapy, which is related to neutrophilic inflammation. Recently, the tumor necrosis factor superfamily member (TNFSF) 14/LIGHT has been recognized as a key mediator in severe asthmatic airway inflammation. However, the profiles and intracellular mechanisms of cytokine/chemokine production induced in cells by LIGHT are poorly understood. We aimed to elucidate the molecular mechanism of LIGHT-induced cytokine/chemokine production by bronchial epithelial cells. Human bronchial epithelial cells express lymphotoxin β receptor (LTβR), but not herpesvirus entry mediator, which are receptors for LIGHT. LIGHT induced various cytokines/chemokines, such as interleukin (IL)-6, oncostatin M, monocyte chemotactic protein-1, growth-regulated protein α and IL-8. Specific siRNA for LTβR attenuated IL-6 and IL-8 production by BEAS-2B and normal human bronchial epithelial cells. LIGHT activated intracellular signaling, such as mitogen-activated protein kinase and nuclear factor-κB (NF-κB) signaling. LIGHT also induced luciferase activity of NF-κB response element, but not of activator protein-1 or serum response element. Specific inhibitors of phosphorylation of extracellular signal-regulated kinase (Erk) and that of inhibitor κB attenuated IL-8 production, suggesting that LIGHT-LTβR signaling induces IL-8 production via the Erk and NF-κB pathways. LIGHT, via LTβR signaling, may contribute to exacerbation of airway neutrophilic inflammation through cytokine and chemokine production by bronchial epithelial cells.

Show MeSH
Related in: MedlinePlus