| Title | Bestrophin-1 encodes for the Ca2+-activated anion channel in hippocampal astrocytes. | | Author(s) | Park H, Oh SJ, Han KS, Woo DH, Park H, Mannaioni G, Traynelis SF, Lee CJ | | Institution | Center for Neural Science, Convergence Technology Laboratory, Korea Institute of Science and Technology, Seoul 136-791, Korea. | | Source | J Neurosci 2009 Oct 14; 29(41):13063-73. | | MeSH | Adenosine Triphosphate
Analysis of Variance
Animals
Animals, Newborn
Astrocytes
Bradykinin
Calcium
Cells, Cultured
Cerebral Cortex
Chelating Agents
Chloride Channels
Dinoprostone
Egtazic Acid
Electric Stimulation
Enzyme Inhibitors
Estrenes
Eye Proteins
Gene Expression Regulation
Hippocampus
Humans
Lysophospholipids
Membrane Potentials
Mice
Mice, Inbred C57BL
Oligopeptides
Patch-Clamp Techniques
Pyrrolidinones
RNA, Small Interfering
Thapsigargin
Thionucleotides
Transfection
| | Abstract | In mammalian brain, neurons and astrocytes are reported to express various chloride and anion channels, but the evidence for functional expression of Ca(2+)-activated anion channel (CAAC) and its molecular identity have been lacking. Here we report electrophysiological evidence for the CAAC expression and its molecular identity by mouse Bestrophin 1 (mBest1) in astrocytes of the mouse brain. Using Ca(2+) imaging and perforated-patch-clamp analysis, we demonstrate that astrocytes displayed an inward current at holding potential of -70 mV that was dependent on an increase in intracellular Ca(2+) after G(alphaq)-coupled receptor activation. This current was mediated mostly by anions and was sensitive to well known anion channel blockers such as niflumic acid, 5-nitro-2(3-phenylpropylamino)-benzoic acid, and flufenamic acid. To find the molecular identity of the anion channel responsible for the CAAC current, we analyzed the expression of candidate genes and found that the mRNA for mouse mBest1 is predominantly expressed in acutely dissociated or cultured astrocytes. Whole-cell patch-clamp analysis using HEK293T cells heterologously expressing full-length mBest1 showed a Ca(2+)-dependent current mediated by mBest1, with a complete impairment of the current by a putative pore mutation, W93C. Furthermore, mBest1-mediated CAAC from cultured astrocytes was significantly reduced by expression of mBest1-specific short hairpin RNA (shRNA), suggesting that the CAAC is mediated by a channel encoded by mBest1. Finally, hippocampal CA1 astrocytes in hippocampal slice also showed mBest1-mediated CAAC because it was inhibited by mBest1-specific shRNA. Collectively, these data provide molecular evidence that the mBest1 channel is responsible for CAAC function in astrocytes. | | Language | eng | | Pub Type(s) | In Vitro
Journal Article
Research Support, N.I.H., Extramural
Research Support, Non-U.S. Gov't
| | PubMed ID | 19828819 |
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