IFN-γ-mediated reduction of large-conductance, Ca2+-activated, voltage-dependent K+ (BK) channel activity in airway epithelial cells leads to mucociliary dysfunction
| Autor: | Dahis Manzanares, Maria Srinivasan, Gregory E. Conner, Matthias Salathe, Pedro I. Ivonnet, John S. Dennis, Samuel Tobias Salathe, Nathalie Baumlin |
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| Rok vydání: | 2014 |
| Předmět: |
Pulmonary and Respiratory Medicine
BK channel Cystic Fibrosis Large-Conductance Calcium-Activated Potassium Channel beta Subunits Physiology Mucociliary clearance Protein subunit Bronchi Nerve Tissue Proteins Respiratory Mucosa Interferon-gamma Chlorides Physiology (medical) KCNMB2 Humans Secretion Large-Conductance Calcium-Activated Potassium Channel alpha Subunits Electrochemical gradient Intramolecular Transferases Cells Cultured Gene knockdown NADPH oxidase biology Arabidopsis Proteins Chemistry NADPH Oxidases Hydrogen Peroxide Articles Cell Biology Dual Oxidases Neoplasm Proteins Cell biology Trachea Biochemistry Mucociliary Clearance biology.protein |
| Zdroj: | American Journal of Physiology-Lung Cellular and Molecular Physiology. 306:L453-L462 |
| ISSN: | 1522-1504 1040-0605 |
| DOI: | 10.1152/ajplung.00247.2013 |
| Popis: | Effective mucociliary clearance (MCC) depends in part on adequate airway surface liquid (ASL) volume to maintain an appropriate periciliary fluid height that allows normal ciliary activity. Apically expressed large-conductance, Ca2+-activated, and voltage-dependent K+ (BK) channels provide an electrochemical gradient for Cl− secretion and thus play an important role for adequate airway hydration. Here we show that IFN-γ decreases ATP-mediated apical BK activation in normal human airway epithelial cells cultured at the air-liquid interface. IFN-γ decreased mRNA levels of KCNMA1 but did not affect total protein levels. Because IFN-γ upregulates dual oxidase (DUOX)2 and therefore H2O2 production, we hypothesized that BK inactivation could be mediated by BK oxidation. However, DUOX2 knockdown did not affect the IFN-γ effect on BK activity. IFN-γ changed mRNA levels of the BK β-modulatory proteins KCNMB2 (increased) and KCNMB4 (decreased) as well as leucine-rich repeat-containing protein (LRRC)26 (decreased). Mallotoxin, a BK opener only in the absence of LRRC26, showed that BK channels lost their association with LRRC26 after IFN-γ treatment. Finally, IFN-γ caused a decrease in ciliary beating frequency that was immediately rescued by apical fluid addition, suggesting that it was due to ASL volume depletion. These data were confirmed with direct ASL measurements using meniscus scanning. Overexpression of KCNMA1, the pore-forming subunit of BK, overcame the reduction of ASL volume induced by IFN-γ. Key experiments were repeated in cystic fibrosis cells and showed the same results. Therefore, IFN-γ induces mucociliary dysfunction through BK inactivation. |
| Databáze: | OpenAIRE |
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