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Toluene diisocyanate exposure induces airway inflammation of bronchial epithelial cells via the activation of transient receptor potential melastatin 8

View Article: PubMed Central - PubMed

ABSTRACT

Toluene diisocyanate (TDI) is the most important cause of occupational asthma (OA), and various pathogenic mechanisms have been suggested. Of these mechanisms, neurogenic inflammation is an important inducer of airway inflammation. Transient receptor potential melastatin 8 (TRPM8) is a well-established cold-sensing cation channel that is expressed in both neuronal cells and bronchial epithelial cells. A recent genome-wide association study of TDI-exposed workers found a significant association between the phenotype of TDI-induced OA and the single-nucleotide polymorphism rs10803666, which has been mapped to the TRPM8 gene. We hypothesized that TRPM8 located in airway epithelial cells may be involved in the pathogenic mechanisms of TDI-induced OA and investigated its role. Bronchial epithelial cells were treated with TDI in a dose- and time-dependent manner. The expression levels of TRPM8 mRNA and protein were determined by quantitative real-time polymerase chain reaction and western blotting. TDI-induced morphological changes in the cells were evaluated by immunocytochemistry. Alterations in the transcripts of inflammatory cytokines were examined in accordance with TRPM8 activation by TDI. TRPM8 expression at both the mRNA and protein levels was enhanced by TDI in airway epithelial cells. TRPM8 activation by TDI led to significant increases in the mRNA of interleukin (IL)-4, IL-13, IL-25 and IL-33. The increased expression of the cytokine genes by TDI was partly attenuated after treatment with a TRPM8 antagonist. TDI exposure induces increased expression of TRPM8 mRNA in airway epithelial cells coupled with enhanced expression of inflammatory cytokines, suggesting a novel role of TRPM8 in the pathogenesis of TDI-induced OA.

No MeSH data available.


Expression of TRPM8 (a) mRNA and (b) protein in lung epithelial cells. Agarose gel demonstrating the presence of a 583-nt PCR product from a human bronchial epithelial cell line (BEAS-2B). The normalized (β-action) PCR product intensities are shown below. Menthol (2–6 mM) treatment for 3 h induced increases in both TRPM8 mRNA and protein expression. Each bar corresponds to the mean normalized product intensity and s.d. An asterisk represents statistically significant increases in mRNA and protein expression relative to untreated cells (paired t-test, *P<0.05, **P<0.01, ***P<0.001).
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fig1: Expression of TRPM8 (a) mRNA and (b) protein in lung epithelial cells. Agarose gel demonstrating the presence of a 583-nt PCR product from a human bronchial epithelial cell line (BEAS-2B). The normalized (β-action) PCR product intensities are shown below. Menthol (2–6 mM) treatment for 3 h induced increases in both TRPM8 mRNA and protein expression. Each bar corresponds to the mean normalized product intensity and s.d. An asterisk represents statistically significant increases in mRNA and protein expression relative to untreated cells (paired t-test, *P<0.05, **P<0.01, ***P<0.001).

Mentions: We investigated whether TRPM8 is expressed on BEAS-2B cells. Expression of TRPM8 was identified using RT-PCR. Figure 1 shows the amplified PCR products generated after 35 cycles and the TRPM8 protein expression using western blot analysis. TRPM8 activation by menthol for 3 h led to significant increases in both the TRPM8 transcript and protein in a dose-dependent manner.


Toluene diisocyanate exposure induces airway inflammation of bronchial epithelial cells via the activation of transient receptor potential melastatin 8
Expression of TRPM8 (a) mRNA and (b) protein in lung epithelial cells. Agarose gel demonstrating the presence of a 583-nt PCR product from a human bronchial epithelial cell line (BEAS-2B). The normalized (β-action) PCR product intensities are shown below. Menthol (2–6 mM) treatment for 3 h induced increases in both TRPM8 mRNA and protein expression. Each bar corresponds to the mean normalized product intensity and s.d. An asterisk represents statistically significant increases in mRNA and protein expression relative to untreated cells (paired t-test, *P<0.05, **P<0.01, ***P<0.001).
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC5382555&req=5

fig1: Expression of TRPM8 (a) mRNA and (b) protein in lung epithelial cells. Agarose gel demonstrating the presence of a 583-nt PCR product from a human bronchial epithelial cell line (BEAS-2B). The normalized (β-action) PCR product intensities are shown below. Menthol (2–6 mM) treatment for 3 h induced increases in both TRPM8 mRNA and protein expression. Each bar corresponds to the mean normalized product intensity and s.d. An asterisk represents statistically significant increases in mRNA and protein expression relative to untreated cells (paired t-test, *P<0.05, **P<0.01, ***P<0.001).
Mentions: We investigated whether TRPM8 is expressed on BEAS-2B cells. Expression of TRPM8 was identified using RT-PCR. Figure 1 shows the amplified PCR products generated after 35 cycles and the TRPM8 protein expression using western blot analysis. TRPM8 activation by menthol for 3 h led to significant increases in both the TRPM8 transcript and protein in a dose-dependent manner.

View Article: PubMed Central - PubMed

ABSTRACT

Toluene diisocyanate (TDI) is the most important cause of occupational asthma (OA), and various pathogenic mechanisms have been suggested. Of these mechanisms, neurogenic inflammation is an important inducer of airway inflammation. Transient receptor potential melastatin 8 (TRPM8) is a well-established cold-sensing cation channel that is expressed in both neuronal cells and bronchial epithelial cells. A recent genome-wide association study of TDI-exposed workers found a significant association between the phenotype of TDI-induced OA and the single-nucleotide polymorphism rs10803666, which has been mapped to the TRPM8 gene. We hypothesized that TRPM8 located in airway epithelial cells may be involved in the pathogenic mechanisms of TDI-induced OA and investigated its role. Bronchial epithelial cells were treated with TDI in a dose- and time-dependent manner. The expression levels of TRPM8 mRNA and protein were determined by quantitative real-time polymerase chain reaction and western blotting. TDI-induced morphological changes in the cells were evaluated by immunocytochemistry. Alterations in the transcripts of inflammatory cytokines were examined in accordance with TRPM8 activation by TDI. TRPM8 expression at both the mRNA and protein levels was enhanced by TDI in airway epithelial cells. TRPM8 activation by TDI led to significant increases in the mRNA of interleukin (IL)-4, IL-13, IL-25 and IL-33. The increased expression of the cytokine genes by TDI was partly attenuated after treatment with a TRPM8 antagonist. TDI exposure induces increased expression of TRPM8 mRNA in airway epithelial cells coupled with enhanced expression of inflammatory cytokines, suggesting a novel role of TRPM8 in the pathogenesis of TDI-induced OA.

No MeSH data available.