The impact of cigarette smoke exposure, COPD, or asthma status on ABC transporter gene expression in human airway epithelial cells

Jennifer A Aguiar,Anna Dvorkin-Gheva,Yechan Kim,Briallen Lobb,Andrea Tamminga,Jeremy A Hirota,Martin R Stampfli,Ryan D Huff,Andrew C Doxey,Jenny P Nguyen

doi:10.1038/s41598-018-36248-9

Abstract

ABC transporters are conserved in prokaryotes and eukaryotes, with humans expressing 48 transporters divided into 7 classes (ABCA, ABCB, ABCC, ABCD, ABDE, ABCF, and ABCG). Throughout the human body, ABC transporters regulate cAMP levels, chloride secretion, lipid transport, and anti-oxidant responses. We used a bioinformatic approach complemented with in vitro experimental methods for validation of the 48 known human ABC transporters in airway epithelial cells using bronchial epithelial cell gene expression datasets available in NCBI GEO from well-characterized patient populations of healthy subjects and individuals that smoke cigarettes, or have been diagnosed with COPD or asthma, with validation performed in Calu-3 airway epithelial cells. Gene expression data demonstrate that ABC transporters are variably expressed in epithelial cells from different airway generations, regulated by cigarette smoke exposure (ABCA13, ABCB6, ABCC1, and ABCC3), and differentially expressed in individuals with COPD and asthma (ABCA13, ABCC1, ABCC2, ABCC9). An in vitro cell culture model of cigarette smoke exposure was able to recapitulate select observed in situ changes. Our work highlights select ABC transporter candidates of interest and a relevant in vitro model that will enable a deeper understanding of the contribution of ABC transporters in the respiratory mucosa in lung health and disease.

Highlights

The respiratory mucosa, extending from the upper airways down to simple squamous epithelium, provides a continuous physical barrier with immune function that helps protect us from any potentially harmful substances contained in the air we breathe[1,2]
The contribution of ATP Binding Cassette (ABC) transporters to respiratory mucosal immunology remains to be defined. To address this knowledge group, we performed a bioinformatic analysis of 9 distinct gene-expression datasets of primary human airway epithelial cells test our hypothesis that specific ABC transporter gene expression patterns would correlate with presence of a specific chronic respiratory disease and disease severity
Data demonstrate that ABC transporters are i) variably expressed in epithelial cells from different airway generations regulated by cigarette smoke exposure (ABCA13, ABCB6, ABCC1, and ABCC3), and iii) differentially expressed in individuals with COPD and asthma (ABCA13, ABCC1, ABCC2, ABCC9)

Summary

Introduction

The respiratory mucosa, extending from the upper airways down to simple squamous epithelium, provides a continuous physical barrier with immune function that helps protect us from any potentially harmful substances contained in the air we breathe[1,2]. Our group has recently confirmed that ABCC4 is expressed in airway epithelial cells[4,5], is able to transport cAMP and uric acid[5], and can modulate anti-inflammatory activities of long-acting beta-agonist/glucocorticoid therapies[6] and potentiate CFTR in select patient populations[14]. These three mechanistic and clinically relevant examples represent only a fraction of the 48 transporters that remain to be more extensively studied in the respiratory mucosa for expression patterns and function in lung health and disease. We conclude that continued research into the basic biology of ABC transporters in the respiratory mucosa with mechanistic approaches is required to truly define the importance of these molecules in lung health and disease

Methods

Results

Conclusion