Bestrophin-1 encodes for the Ca2+-activated anion channel in hippocampal astrocytes.
Bestrophin-1 encodes for the Ca2+-activated anion channel in hippocampal astrocytes.
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DOI：
10.1523/jneurosci.3193-09.2009
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发表时间：
2009-10-14
期刊：
影响因子：
--
通讯作者：
Lee CJ
中科院分区：
文献类型：
--
作者：
Park H;Oh SJ;Han KS;Woo DH;Park H;Mannaioni G;Traynelis SF;Lee CJ
据报道，在哺乳动物大脑中，神经元和星形胶质细胞表达各种氯离子通道和阴离子通道，但缺乏 Ca2+ 激活阴离子通道 (CAAC) 功能表达及其分子特性的证据。在这里，我们报告了小鼠脑星形胶质细胞中小鼠 Bestropin 1 (mBest1) 的 CAAC 表达及其分子身份的电生理学证据。使用 Ca2+ 成像和穿孔膜片钳分析，我们证明星形胶质细胞在 -70 mV 的保持电位下表现出内向电流，这取决于 Gαq 偶联受体激活后细胞内 Ca2+ 的增加。该电流主要由阴离子介导，并且对众所周知的阴离子通道阻滞剂如尼氟酸、NPPB 和氟芬那酸敏感。为了找到负责 CAAC 电流的阴离子通道的分子身份，我们分析了候选基因的表达，发现小鼠 Bestropin 1 (mBest1) 的 mRNA 主要在急性解离或培养的星形胶质细胞中表达。使用异源表达全长 mBest1 的 HEK293T 细胞进行的全细胞膜片钳分析显示，mBest1 介导 Ca2+ 依赖性电流，并且假定的孔突变 W93C 导致电流完全受损。此外，mBest1 特异性 shRNA 的表达显着降低了培养星形胶质细胞中 mBest1 介导的 CAAC，表明 CAAC 是由 mBest1 编码的通道介导的。最后，海马切片中的海马 CA1 星形胶质细胞也显示出 mBest1 介导的 CAAC，因为它受到 mBest1 特异性 shRNA 的抑制。总的来说，这些数据提供了 mBest1 通道负责星形胶质细胞中 CAAC 功能的分子证据。
In mammalian brain, neurons and astrocytes are reported to express various chloride and anion channels, but the evidence for functional expression of Ca2+-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 Ca2+-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 Ca2+ following upon Gαq-coupled receptor activation. This current was mediated mostly by anions and was sensitive to well-known anion channel blockers such as niflumic acid, NPPB, 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 Bestrophin 1 (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 Ca2+-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 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 as it was inhibited by mBest1-specific shRNA. Collectively, these data provide molecular evidence that the mBest1 channel is responsible for CAAC function in astrocytes.
豚鼠大肠杆菌心肌的Ca2+活化的钾通道的渗透，选择性和阻塞。
DOI：
10.1085/jgp.94.5.849
发表时间：
1989-11
期刊：
The Journal of general physiology
影响因子：
--
作者：
Hu SL;Yamamoto Y;Kao CY
通讯作者：
Kao CY