Abstract
Ca2+ activated Cl- transport is found in airways and other organs and is abnormal in cystic fibrosis, polycystic kidney disease and infectious diarrhea. The molecular identity of Ca2+ activated Cl- channels (CaCC) in the airways is still obscure. Bestrophin proteins were described to form CaCC and to regulate voltage gated Ca2+ channels. The present Ussing chamber recordings on tracheas of bestrophin 1 knockout (vmd2-/-) mice indicate a reduced Cl- secretion when activated by the purinergic agonist ATP (0.1-1 μM). As two paralogs, best1 and best2, are present in mouse tracheal epithelium, we examined the contribution of each paralog to Ca2+ activated Cl- secretion. In whole cell patch-clamp measurements on primary airway epithelial cells from vmd2-/- tracheas, ATP activated Cl- currents were reduced by 50%. Additional knockdown of mbest2 in vmd2-/- cells by short interfering RNA further suppressed ATP-induced Cl- currents down to 20% of that observed in cells from vmd2+/+ animals. Moreover, RNAi-suppression of both mbest1 and mbest2 reduced CaCC in vmd2+/+ cells. Direct activation of CaCC by increase of intracellular Ca2+ was also reduced in whole cell recordings of vmd2-/- cells. These results clearly suggest a role of bestrophin 1 and 2 for Ca2+ dependent Cl- secretion in mouse airways.
Original language | English (US) |
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Pages (from-to) | 1993-2000 |
Number of pages | 8 |
Journal | Biochimica et Biophysica Acta - Molecular Cell Research |
Volume | 1783 |
Issue number | 10 |
DOIs | |
State | Published - Oct 1 2008 |
Externally published | Yes |
Keywords
- Airways
- Bestrophin 1
- Bestrophin 2
- Ca activated Cl channel
- Cl conductance
- Epithelium
- Vmd2
ASJC Scopus subject areas
- Molecular Biology
- Cell Biology