Functional KCa3.1 K+ channels are required for human fibrocyte migration - 30/11/11
Abstract |
Background |
Fibrocytes are bone marrow–derived CD34+ collagen I–positive cells present in peripheral blood that develop ⍺-smooth muscle actin expression and contractile activity in tissue culture. They are implicated in the pathogenesis of tissue remodeling and fibrosis in both patients with asthma and those with idiopathic pulmonary fibrosis. Targeting fibrocyte migration might therefore offer a new approach for the treatment of these diseases. Ion channels play key roles in cell function, but the ion-channel repertoire of human fibrocytes is unknown.
Objective |
We sought to examine whether human fibrocytes express the KCa3.1 K+ channel and to determine its role in cell differentiation, survival, and migration.
Methods |
Fibrocytes were cultured from the peripheral blood of healthy subjects and patients with asthma. Whole-cell patch-clamp electrophysiology was used for the measurement of ion currents, whereas mRNA and protein were examined to confirm channel expression. Fibrocyte migration and proliferation assays were performed in the presence of KCa3.1 ion-channel blockers.
Results |
Human fibrocytes cultured from the peripheral blood of both healthy control subjects and asthmatic patients expressed robust KCa3.1 ion currents together with KCa3.1 mRNA and protein. Two specific and distinct KCa3.1 blockers (TRAM-34 and ICA-17043) markedly inhibited fibrocyte migration in transwell migration assays. Channel blockers had no effect on fibrocyte growth, apoptosis, or differentiation in cell culture.
Conclusions |
The K+ channel KCa3.1 plays a key role in human fibrocyte migration. Currently available KCa3.1-channel blockers might therefore attenuate tissue fibrosis and remodeling in patients with diseases such as idiopathic pulmonary fibrosis and asthma through the inhibition of fibrocyte recruitment.
Le texte complet de cet article est disponible en PDF.Key words : Pulmonary fibrosis, asthma, fibrocyte, cell migration, ion channel, KCa3.1, patch clamp electrophysiology
Abbreviations used : 1-EBIO, ⍺SMA, ASM, IPF, Kd
Plan
Supported by a Wellcome Trust Senior Clinical Fellowship (grant 082265) and Asthma UK (grant 07/007). This research was conducted in laboratories part-funded by ERDF no. 05567. |
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Disclosure of potential conflict of interest: R. Saunders receives research support from Asthma UK. C. E. Brightling has consultant arrangements with GlaxoSmithKline, Novartis, Genentech, Roche, Chiesi, MedImmune, and AstraZeneca and receives research support from GlaxoSmithKline, Novartis, Chiesi, MedImmune, and AstraZeneca. P. Bradding has had consultant arrangements with Icagen, Inc. The rest of the authors have declared that they have no conflict of interest. |
Vol 128 - N° 6
P. 1303 - décembre 2011 Retour au numéroBienvenue sur EM-consulte, la référence des professionnels de santé.
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