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Wnt/β-catenin signaling modulates human airway sensitization induced by β2-adrenoceptor stimulation.

Faisy C, Grassin-Delyle S, Blouquit-Laye S, Brollo M, Naline E, Chapelier A, Devillier P - PLoS ONE (2014)

Bottom Line: Compared to paired controls, fenoterol-sensitization was abolished by inhibition/blockage of the Wnt/β-catenin signaling, especially the cell-surface LRP5/6 co-receptors or Fzd receptors (1 µM SFRP1 or 1 µM DKK1) and the nuclear recruitment of TCF/LEF transcriptions factors (0.3 µM FH535).Wnt proteins secretion did not seem to be involved in the fenoterol-induced sensitization since the mRNA expression of Wnt remained low after fenoterol exposure and the inactivator of Wnt secretion (1 µM IWP2) had no effect on the fenoterol-sensitization.Collectively, our pharmacological investigations indicate that fenoterol-sensitization is modulated by the inhibition/blockage of canonical Wnt/β-catenin pathway, suggesting a phenomenon of biased agonism in connection with the β2-adrenoceptor stimulation.

View Article: PubMed Central - PubMed

Affiliation: Unité Propre de Recherche de l'Enseignement Supérieur, Equipe d'Accueil 220, Université Versailles Saint-Quentin, Hôpital Foch, Suresnes, France; Medical Intensive Care Unit, Hôpital Européen Georges Pompidou, Assistance Publique-Hôpitaux de Paris, Paris, France.

ABSTRACT

Background: Regular use of β2-agonists may enhance non-specific airway responsiveness. The wingless/integrated (Wnt) signaling pathways are responsible for several cellular processes, including airway inflammation and remodeling while cAMP-PKA cascade can activate the Wnt signaling. We aimed to investigate whether the Wnt signaling pathways are involved in the bronchial hyperresponsiveness induced by prolonged exposure to β2-adrenoceptor agonists in human isolated airways.

Methods: Bronchi were surgically removed from 44 thoracic surgery patients. After preparation, bronchial rings and primary cultures of bronchial epithelial cells were incubated with fenoterol (0.1 µM, 15 hours, 37 °C), a β2-agonist with high intrinsic efficacy. The effects of inhibitors/blockers of Wnt signaling on the fenoterol-induced airway sensitization were examined and the impact of fenoterol exposure on the mRNA expression of genes interacting with Wnt signaling or cAMP-PKA cascade was assessed in complete bronchi and in cultured epithelial cells.

Results: Compared to paired controls, fenoterol-sensitization was abolished by inhibition/blockage of the Wnt/β-catenin signaling, especially the cell-surface LRP5/6 co-receptors or Fzd receptors (1 µM SFRP1 or 1 µM DKK1) and the nuclear recruitment of TCF/LEF transcriptions factors (0.3 µM FH535). Wnt proteins secretion did not seem to be involved in the fenoterol-induced sensitization since the mRNA expression of Wnt remained low after fenoterol exposure and the inactivator of Wnt secretion (1 µM IWP2) had no effect on the fenoterol-sensitization. Fenoterol exposure did not change the mRNA expression of genes regulating Wnt signaling or cAMP-PKA cascade.

Conclusions: Collectively, our pharmacological investigations indicate that fenoterol-sensitization is modulated by the inhibition/blockage of canonical Wnt/β-catenin pathway, suggesting a phenomenon of biased agonism in connection with the β2-adrenoceptor stimulation. Future experiments based on the results of the present study will be needed to determine the impact of prolonged fenoterol exposure on the extra- and intracellular Wnt signaling pathways at the protein expression level.

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Related in: MedlinePlus

Gene-expression in complete human bronchi at basal state (H0) and after 15 hours of incubation (H15) with 0.1 µM fenoterol or Krebs–Henseleit solution (paired controls).Data are expressed as relative expression (where ΔCt is the difference between the target gene Ct and the mean Ct of the reference genes). Values are means ± SEM (n = 8). No difference between fenoterol and paired controls were statistically significant.
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pone-0111350-g003: Gene-expression in complete human bronchi at basal state (H0) and after 15 hours of incubation (H15) with 0.1 µM fenoterol or Krebs–Henseleit solution (paired controls).Data are expressed as relative expression (where ΔCt is the difference between the target gene Ct and the mean Ct of the reference genes). Values are means ± SEM (n = 8). No difference between fenoterol and paired controls were statistically significant.

Mentions: The mRNA levels of the 3 housekeeping genes were unaffected by incubation with fenoterol or incubation time (not shown). At basal state (H0), whole human bronchi mainly expressed FZD6 mRNA while the WNTs expression was low, and WIF1 expression remained practically undetectable (Fig. 3). Incubation with Krebs-Henseleit solution for 15 hours led to a rise in GADD45A mRNA expression, a gene involved in p38/JNK activation (Fig. 3). Compared to paired tissues incubated with Krebs-Henseleit solution, incubation with 0.1 µM fenoterol for 15 hours did not alter the mRNA expression of genes related to Wnt signaling pathway (FZD1-10, WNT2, WNT3A, WNT5A, WNT7B, WNT10A, WNT11, LRP5/6, and WISP1) or genes interacting with the modulation of cAMP–PKA cascade (SLC9A3R1, PPP2R1A, EP300, CTBP1, and FRAT1) or the p38/JNK or Rho/MAPK signaling pathways (PKCE and GADD45A) (Fig. 3). Moreover, FZD6, WNT7B and LRP5 mRNA were mostly expressed by cultured human bronchial epithelial cells (Fig. 4). Compared to paired controls, mRNA expression of the genes of interest did not appear to be changed in fenoterol-treated epithelial cells (Fig. 4).


Wnt/β-catenin signaling modulates human airway sensitization induced by β2-adrenoceptor stimulation.

Faisy C, Grassin-Delyle S, Blouquit-Laye S, Brollo M, Naline E, Chapelier A, Devillier P - PLoS ONE (2014)

Gene-expression in complete human bronchi at basal state (H0) and after 15 hours of incubation (H15) with 0.1 µM fenoterol or Krebs–Henseleit solution (paired controls).Data are expressed as relative expression (where ΔCt is the difference between the target gene Ct and the mean Ct of the reference genes). Values are means ± SEM (n = 8). No difference between fenoterol and paired controls were statistically significant.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4216012&req=5

pone-0111350-g003: Gene-expression in complete human bronchi at basal state (H0) and after 15 hours of incubation (H15) with 0.1 µM fenoterol or Krebs–Henseleit solution (paired controls).Data are expressed as relative expression (where ΔCt is the difference between the target gene Ct and the mean Ct of the reference genes). Values are means ± SEM (n = 8). No difference between fenoterol and paired controls were statistically significant.
Mentions: The mRNA levels of the 3 housekeeping genes were unaffected by incubation with fenoterol or incubation time (not shown). At basal state (H0), whole human bronchi mainly expressed FZD6 mRNA while the WNTs expression was low, and WIF1 expression remained practically undetectable (Fig. 3). Incubation with Krebs-Henseleit solution for 15 hours led to a rise in GADD45A mRNA expression, a gene involved in p38/JNK activation (Fig. 3). Compared to paired tissues incubated with Krebs-Henseleit solution, incubation with 0.1 µM fenoterol for 15 hours did not alter the mRNA expression of genes related to Wnt signaling pathway (FZD1-10, WNT2, WNT3A, WNT5A, WNT7B, WNT10A, WNT11, LRP5/6, and WISP1) or genes interacting with the modulation of cAMP–PKA cascade (SLC9A3R1, PPP2R1A, EP300, CTBP1, and FRAT1) or the p38/JNK or Rho/MAPK signaling pathways (PKCE and GADD45A) (Fig. 3). Moreover, FZD6, WNT7B and LRP5 mRNA were mostly expressed by cultured human bronchial epithelial cells (Fig. 4). Compared to paired controls, mRNA expression of the genes of interest did not appear to be changed in fenoterol-treated epithelial cells (Fig. 4).

Bottom Line: Compared to paired controls, fenoterol-sensitization was abolished by inhibition/blockage of the Wnt/β-catenin signaling, especially the cell-surface LRP5/6 co-receptors or Fzd receptors (1 µM SFRP1 or 1 µM DKK1) and the nuclear recruitment of TCF/LEF transcriptions factors (0.3 µM FH535).Wnt proteins secretion did not seem to be involved in the fenoterol-induced sensitization since the mRNA expression of Wnt remained low after fenoterol exposure and the inactivator of Wnt secretion (1 µM IWP2) had no effect on the fenoterol-sensitization.Collectively, our pharmacological investigations indicate that fenoterol-sensitization is modulated by the inhibition/blockage of canonical Wnt/β-catenin pathway, suggesting a phenomenon of biased agonism in connection with the β2-adrenoceptor stimulation.

View Article: PubMed Central - PubMed

Affiliation: Unité Propre de Recherche de l'Enseignement Supérieur, Equipe d'Accueil 220, Université Versailles Saint-Quentin, Hôpital Foch, Suresnes, France; Medical Intensive Care Unit, Hôpital Européen Georges Pompidou, Assistance Publique-Hôpitaux de Paris, Paris, France.

ABSTRACT

Background: Regular use of β2-agonists may enhance non-specific airway responsiveness. The wingless/integrated (Wnt) signaling pathways are responsible for several cellular processes, including airway inflammation and remodeling while cAMP-PKA cascade can activate the Wnt signaling. We aimed to investigate whether the Wnt signaling pathways are involved in the bronchial hyperresponsiveness induced by prolonged exposure to β2-adrenoceptor agonists in human isolated airways.

Methods: Bronchi were surgically removed from 44 thoracic surgery patients. After preparation, bronchial rings and primary cultures of bronchial epithelial cells were incubated with fenoterol (0.1 µM, 15 hours, 37 °C), a β2-agonist with high intrinsic efficacy. The effects of inhibitors/blockers of Wnt signaling on the fenoterol-induced airway sensitization were examined and the impact of fenoterol exposure on the mRNA expression of genes interacting with Wnt signaling or cAMP-PKA cascade was assessed in complete bronchi and in cultured epithelial cells.

Results: Compared to paired controls, fenoterol-sensitization was abolished by inhibition/blockage of the Wnt/β-catenin signaling, especially the cell-surface LRP5/6 co-receptors or Fzd receptors (1 µM SFRP1 or 1 µM DKK1) and the nuclear recruitment of TCF/LEF transcriptions factors (0.3 µM FH535). Wnt proteins secretion did not seem to be involved in the fenoterol-induced sensitization since the mRNA expression of Wnt remained low after fenoterol exposure and the inactivator of Wnt secretion (1 µM IWP2) had no effect on the fenoterol-sensitization. Fenoterol exposure did not change the mRNA expression of genes regulating Wnt signaling or cAMP-PKA cascade.

Conclusions: Collectively, our pharmacological investigations indicate that fenoterol-sensitization is modulated by the inhibition/blockage of canonical Wnt/β-catenin pathway, suggesting a phenomenon of biased agonism in connection with the β2-adrenoceptor stimulation. Future experiments based on the results of the present study will be needed to determine the impact of prolonged fenoterol exposure on the extra- and intracellular Wnt signaling pathways at the protein expression level.

Show MeSH
Related in: MedlinePlus