Inhibition of β-Catenin/CREB Binding Protein Signaling Attenuates House Dust Mite-Induced Goblet Cell Metaplasia in Mice.

Philip M Hansbro,Virinchi N S Kuchibhotla,Martijn C Nawijn,Andrew T Reid,Darryl A Knight,Malcolm R Starkey,Irene H Heijink

doi:10.3389/fphys.2021.690531

Abstract

Excessive mucus production is a major feature of allergic asthma. Disruption of epithelial junctions by allergens such as house dust mite (HDM) results in the activation of β-catenin signaling, which has been reported to stimulate goblet cell differentiation. β-catenin interacts with various co-activators including CREB binding protein (CBP) and p300, thereby regulating the expression of genes involved in cell proliferation and differentiation, respectively. We specifically investigated the role of the β-catenin/CBP signaling pathway in goblet cell metaplasia in a HDM-induced allergic airway disease model in mice using ICG-001, a small molecule inhibitor that blocks the binding of CBP to β-catenin. Female 6- 8-week-old BALB/c mice were sensitized to HDM/saline on days 0, 1, and 2, followed by intranasal challenge with HDM/saline with or without subcutaneous ICG-001/vehicle treatment from days 14 to 17, and samples harvested 24 h after the last challenge/treatment. Differential inflammatory cells in bronchoalveolar lavage (BAL) fluid were enumerated. Alcian blue (AB)/Periodic acid–Schiff (PAS) staining was used to identify goblet cells/mucus production, and airway hyperresponsiveness (AHR) was assessed using invasive plethysmography. Exposure to HDM induced airway inflammation, goblet cell metaplasia and increased AHR, with increased airway resistance in response to the non-specific spasmogen methacholine. Inhibition of the β-catenin/CBP pathway using treatment with ICG-001 significantly attenuated the HDM-induced goblet cell metaplasia and infiltration of macrophages, but had no effect on eosinophils, neutrophils, lymphocytes or AHR. Increased β-catenin/CBP signaling may promote HDM-induced goblet cell metaplasia in mice.

Highlights

Asthma is broadly characterized by chronic inflammation and remodeling of the airways, excessive airway mucus production, reversible airflow obstruction with loss of lung function (Fehrenbach et al, 2017)
In mice treated with ICG-001, no differences were observed in the Cdh1 mRNA expression levels after house dust mite (HDM) exposure compared to the PBS-exposed controls (Figure 2B)
The increase in Muc5ac and Muc5b expression was validated at the protein level by Alcian blue (AB)/Periodic acid–Schiff (PAS) staining, revealing that HDM exposure promoted goblet cell metaplasia and mucus production compared to the PBS + Vehicle treated controls

Summary

Introduction

Asthma is broadly characterized by chronic inflammation and remodeling of the airways, excessive airway mucus production, reversible airflow obstruction with loss of lung function (Fehrenbach et al, 2017). The airway epithelium is the first line of defense against inhaled allergens and is more susceptible to damage by allergens such as house dust mite (HDM) in asthma. This results in the deterioration of cellular junctions (Heijink et al, 2014), and release of pro-inflammatory cytokines like Chemokine (C-C motif) ligand 20 (CCL20), CCL17, interleukin (IL)-25, IL-33 and thymic stromal lymphopoietin (TSLP), which activate and attract immune cells like dendritic cells (DCs) and macrophages, promoting the differentiation of type-2 cells (Heijink et al, 2007; Hansbro et al, 2013; Hallstrand et al, 2014). MUC5AC production is regulated by the transcription factors SAM pointed domain containing ETS transcription factor (SPDEF) and forkhead box a2 (FOXA2), which activate and repress the expression of MUC5AC, respectively (Evans et al, 2009; Bonser and Erle, 2017)

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Conclusion