Role of airway smooth muscle cell phenotypes in airway tone and obstruction in guinea pig asthma model

Mayra D Álvarez-Santos,Blanca Bazán-Perkins,Elizabeth Eslava-De-Jesus,Ivonne Pacheco-Alba,Yazmín Pérez-Del-Valle,Angel González-López,Marisol Álvarez-González,Rodrigo Rojas-Madrid

doi:10.1186/s13223-022-00645-7

Abstract

BackgroundAirway obstruction (AO) in asthma is driven by airway smooth muscle (ASM) contraction. AO can be induced extrinsically by direct stimulation of ASM with contractile agonists as histamine, or by indirect provocation with antigens as ovalbumin, while the airway tone is dependent on intrinsic mechanisms. The association of the ASM phenotypes involved in different types of AO and airway tone in guinea pigs was evaluated.MethodsGuinea pigs were sensitized to ovalbumin and challenged with antigen. In each challenge, the maximum OA response to ovalbumin was determined, and before the challenges, the tone of the airways. At third challenge, airway responsiveness (AR) to histamine was evaluated and ASM cells from trachea were disaggregated to determinate: (a) by flow cytometry, the percentage of cells that express transforming growth factor-β1 (TGF-β1), interleukin-13 (IL-13) and sarco-endoplasmic Ca2+ ATPase-2b (SERCA2b), (b) by RT-PCR, the SERCA2B gene expression, (c) by ELISA, reduced glutathione (GSH) and, (d) Ca2+ sarcoplasmic reticulum refilling rate by microfluorometry. Control guinea pig group received saline instead ovalbumin.ResultsAntigenic challenges in sensitized guinea pigs induced indirect AO, AR to histamine and increment in airway tone at third challenge. No relationship was observed between AO induced by antigen and AR to histamine with changes in airway tone. The extent of antigen-induced AO was associated with both, TGF-β1 expression in ASM and AR degree. The magnitude of AR and antigen-induced AO showed an inverse correlation with GSH levels in ASM. The airway tone showed an inverse association with SERCA2b expression.ConclusionsOur data suggest that each type of AO and airway tone depends on different ASM phenotypes: direct and indirect AO seems to be sensitive to the level of oxidative stress; indirect obstruction induced by antigen appears to be influenced by the expression of TGF-β1 and the SERCA2b expression level plays a role in the airway tone.

Highlights

Airway smooth muscle (ASM) is a central structure involved in the development of asthma physiopathology since it contributes to the development of airway hyperresponsiveness (AHR) and variable airflow obstruction
airway smooth muscle (ASM) cells were disaggregated from the trachea, and flow cytometry was used to determine the percentages of cells that expressed transforming growth factor β1 (TGF-β1), IL-13 and SERCA2b
The average maximal obstructive response (Rmax) observed during the first through the third antigen challenge was higher in the guinea pig asthma model than in the control group (P < 0.01; n = 6 and 9 for the control and asthma model groups, respectively; Fig. 2a)

Summary

Introduction

Airway smooth muscle (ASM) is a central structure involved in the development of asthma physiopathology since it contributes to the development of airway hyperresponsiveness (AHR) and variable airflow obstruction. In small isolated airways from humans, IL-13 can induce AHR [8], and IL-13 can increase both the baseline airway tone and the airway responsiveness in murine lung slices [3]. Another example is transforming growth factor β1 (TGF-β1), a cytokine that is produced at high levels by ASM cells in asthma. The effects of TGF-β1 on airway contractility are controversial, it is recognized that this cytokine can be involved in airway remodelling by inducing ASM proliferation and fibrosis and increasing airway wall mass [9, 10]. The association of the ASM phenotypes involved in different types of AO and airway tone in guinea pigs was evaluated

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