title: KCa3.1 K+ Channel Expression and Function in Human Bronchial Epithelial Cells.
abstract: The KCa3.1 K+ channel has been proposed as a novel target for pulmonary diseases such as asthma and pulmonary fibrosis. It is expressed in epithelia but its expression and function in primary human bronchial epithelial cells (HBECs) has not been described. Due to its proposed roles in the regulation of cell proliferation, migration, and epithelial fluid secretion, inhibiting this channel might have either beneficial or adverse effects on HBEC function. The aim of this study was to assess whether primary HBECs express the KCa3.1 channel and its role in HBEC function. Primary HBECs from the airways of healthy and asthmatic subjects, SV-transformed BEAS-2B cells and the neoplastic H292 epithelial cell line were studied. Primary HBECs, BEAS-2B and H292 cells expressed KCa3.1 mRNA and protein, and robust KCa3.1 ion currents. KCa3.1 protein expression was increased in asthmatic compared to healthy airway epithelium in situ, and KCa3.1 currents were larger in asthmatic compared to healthy HBECs cultured in vitro. Selective KCa3.1 blockers (TRAM-34, ICA-17043) had no effect on epithelial cell proliferation, wound closure, ciliary beat frequency, or mucus secretion. However, several features of TGFβ1-dependent epithelial-mesenchymal transition (EMT) were inhibited by KCa3.1 blockade. Treatment with KCa3.1 blockers is likely to be safe with respect to airway epithelial biology, and may potentially inhibit airway remodelling through the inhibition of EMT.
authors.affiliation: Department of Infection, Immunity and Inflammation, Institute for Lung Health, University of Leicester, Leicester, United Kingdom.
authors.forename: Greer K
authors.initials: GK
authors.lastname: Arthur
authors.affiliation: Department of Infection, Immunity and Inflammation, Institute for Lung Health, University of Leicester, Leicester, United Kingdom.
authors.forename: S Mark
authors.initials: SM
authors.lastname: Duffy
authors.affiliation: Department of Infection, Immunity and Inflammation, Institute for Lung Health, University of Leicester, Leicester, United Kingdom.
authors.forename: Katy M
authors.initials: KM
authors.lastname: Roach
authors.affiliation: Department of Infection, Immunity and Inflammation, Institute for Lung Health, University of Leicester, Leicester, United Kingdom.
authors.forename: Rob A
authors.initials: RA
authors.lastname: Hirst
authors.affiliation: Department of Infection, Immunity and Inflammation, Institute for Lung Health, University of Leicester, Leicester, United Kingdom.
authors.forename: Aarti
authors.initials: A
authors.lastname: Shikotra
authors.affiliation: Department of Infection, Immunity and Inflammation, Institute for Lung Health, University of Leicester, Leicester, United Kingdom.
authors.forename: Erol A
authors.initials: EA
authors.lastname: Gaillard
authors.affiliation: Department of Infection, Immunity and Inflammation, Institute for Lung Health, University of Leicester, Leicester, United Kingdom.
authors.forename: Peter
authors.initials: P
authors.lastname: Bradding
mesh_terms: D001249:Asthma / Q000378:metabolism; D001980:Bronchi / Q000378:metabolism*; D045744:Cell Line, Tumor; D004847:Epithelial Cells / Q000378:metabolism*; D058750:Epithelial-Mesenchymal Transition; D005786:Gene Expression Regulation; D006801:Humans; D051660:Intermediate-Conductance Calcium-Activated Potassium Channels / Q000037:antagonists & inhibitors / Q000096:biosynthesis*; D020545:Respiratory Mucosa / Q000378:metabolism*; D053773:Transforming Growth Factor beta1 / Q000378:metabolism
chemical_list: D051660:Intermediate-Conductance Calcium-Activated Potassium Channels; C496923:KCNN4 protein, human; C508960:TGFB1 protein, human; D053773:Transforming Growth Factor beta1