ADAM17 and EGFR regulate IL-6 receptor and amphiregulin mRNA expression and release in cigarette smoke-exposed primary bronchial epithelial cells from patients with chronic obstructive pulmonary disease (COPD)

Marta Stolarczyk,Pieter S Hiemstra,Xiao Yu,Mieke Veltman,Gimano D Amatngalim,Bob J Scholte

doi:10.14814/phy2.12878

Abstract

Aberrant activity of a disintegrin and metalloprotease 17 (ADAM17), also known as TACE, and epidermal growth factor receptor (EGFR) has been suggested to contribute to chronic obstructive pulmonary disease (COPD) development and progression. The aim of this study was to investigate the role of these proteins in activation of primary bronchial epithelial cells differentiated at the air–liquid interface (ALI‐PBEC) by whole cigarette smoke (CS), comparing cells from COPD patients with non‐COPD. CS exposure of ALI‐PBEC enhanced ADAM17‐mediated shedding of the IL‐6 receptor (IL6R) and the EGFR agonist amphiregulin (AREG) toward the basolateral compartment, which was more pronounced in cells from COPD patients than in non‐COPD controls. CS transiently increased IL6R and AREG mRNA in ALI‐PBEC to a similar extent in cultures from both groups, suggesting that posttranslational events determine differential shedding between COPD and non‐COPD cultures. We show for the first time by in situ proximity ligation (PLA) that CS strongly enhances interactions of phosphorylated ADAM17 with AREG and IL‐6R in an intracellular compartment, suggesting that CS‐induced intracellular trafficking events precede shedding to the extracellular compartment. Both EGFR and ADAM17 activity contribute to CS‐induced IL‐6R and AREG protein shedding and to mRNA expression, as demonstrated using selective inhibitors (AG1478 and TMI‐2). Our data are consistent with an autocrine‐positive feedback mechanism in which CS triggers shedding of EGFR agonists evoking EGFR activation, in ADAM17‐dependent manner, and subsequently transduce paracrine signaling toward myeloid cells and connective tissue. Reducing ADAM17 and EGFR activity could therefore be a therapeutic approach for the tissue remodeling and inflammation observed in COPD.

Highlights

Chronic obstructive pulmonary disease (COPD) is a progressive lung disorder characterized by irreversible airflow obstruction due to airway inflammation, infection, and tissue remodeling (Vestbo et al 2013)
Our studies focus on two a disintegrin and metalloprotease 17 (ADAM17) substrates implicated in COPD pathogenesis: the IL-6 cytokine receptor (IL6R) and the growth factor amphiregulin (AREG), one of the epidermal growth factor receptor (EGFR) agonists produced by bronchial epithelial cells (Richter et al 2002)
cigarette smoke (CS) significantly increased release of soluble interleukin-6 receptor (sIL6R) into the basal medium at 12 h postexposure, while AREG levels were increased at 12 and 24 h after CS exposure. These results demonstrate that shedding of sIL6R and AREG by air–liquid interface (ALI)-Primary bronchial epithelial cells (PBEC) occurs mainly to the basolateral compartment, and is enhanced by CS exposure

Summary

Introduction

Chronic obstructive pulmonary disease (COPD) is a progressive lung disorder characterized by irreversible airflow obstruction due to airway inflammation, infection, and tissue remodeling (Vestbo et al 2013). The activity of MMPs and ADAMs contributes to proteolytic degradation of lung tissue, and to regulation and processing of numerous receptor activating proteins (Richter et al 2002; Gomez et al 2005; Bell et al 2007; Baumgart et al 2010). Through these various activities, MMPs and ADAMs are implicated in a broad spectrum of processes ranging from inflammatory responses to airway epithelial repair. It has been proposed that their aberrant activity might lead to chronic inflammation and abnormal tissue remodeling in the lungs of COPD patients (Paulissen et al 2009)

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