Cerebrovascular Dilation via Selective Targeting of the Cholane Steroid-Recognition Site in the BK Channel β1-Subunit by a Novel Nonsteroidal Agent
Cerebrovascular Dilation via Selective Targeting of the Cholane Steroid-Recognition Site in the BK Channel β1-Subunit by a Novel Nonsteroidal Agent
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DOI：
10.1124/mol.112.083519
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发表时间：
2013-05-01
影响因子：
3.6
通讯作者：
Dopico, Alex M.
中科院分区：
文献类型：
--
作者：
Bukiya, Anna N.;McMillan, Jacob E.;Dopico, Alex M.
Ca 2 +/电压门控K+大电导（BK）通道β 1亚基在血管平滑肌中特别丰富。通过确定它们的表型，BK β 1允许BK通道降低肌源性张力，促进血管舒张。内源性类固醇石胆酸（LCA）通过BK通道激活扩张脑动脉，这需要通过包括Thr 169的BK β 1位点识别。外源性非甾体药物是否可以进入该部位选择性激活含β 1的BK通道并引起血管舒张仍不清楚。我们进行了化学结构数据库相似性搜索使用LCA作为模板，沿着的两步反应，以生成3-羟基齐墩果-12-烯-30-酸钠（HENA）。HENA激活从大鼠脑动脉肌细胞克隆的BK（cbv 1 + β 1）通道，其效力（EC 50 = 53 μ M）与LCA相似，且效力（x2.5增强）显著大于LCA。这种HENA作用在大鼠脑动脉肌细胞的天然通道上复制。HENA未能激活由cbv 1 + β 2、β 3、β 4或β 1 T169 A组成的通道，表明这种药物通过BK β 1类固醇敏感位点选择性靶向含β 1的BK通道。HENA（3-45 μ M）扩张大鼠和C57 BL/6小鼠加压脑动脉。与电生理结果一致，这种影响大于LCA。HENA不能扩张KCNMB 1基因敲除小鼠的动脉，这强调了BK β 1在HENA作用中的作用。最后，颈动脉输注HENA（45 μ M）通过选择性BK通道靶向扩张软膜脑小动脉。总之，我们首次发现了一种非甾体药物，它通过靶向BK β 1中的甾体敏感位点，选择性激活含β 1的BK通道，使血管舒张。
The Ca2+/voltage-gated K+ large conductance (BK) channel beta 1 subunit is particularly abundant in vascular smooth muscle. By determining their phenotype, BK beta 1 allows the BK channels to reduce myogenic tone, facilitating vasodilation. The endogenous steroid lithocholic acid (LCA) dilates cerebral arteries via BK channel activation, which requires recognition by a BK beta 1 site that includes Thr169. Whether exogenous nonsteroidal agents can access this site to selectively activate beta 1-containing BK channels and evoke vasodilation remain unknown. We performed a chemical structure database similarity search using LCA as a template, along with a two-step reaction to generate sodium 3-hydroxyolean-12-en-30-oate (HENA). HENA activated the BK (cbv1 + beta 1) channels cloned from rat cerebral artery myocytes with a potency (EC50 = 53 mu M) similar to and an efficacy (x2.5 potentiation)significantly greater than that of LCA. This HENA action was replicated on native channels in rat cerebral artery myocytes. HENA failed to activate the channels made of cbv1 + beta 2, beta 3, beta 4, or beta 1T169A, indicating that this drug selectively targets beta 1-containing BK channels via the BK beta 1 steroid-sensing site. HENA (3-45 mu M) dilated the rat and C57BL/6 mouse pressurized cerebral arteries. Consistent with the electrophysiologic results, this effect was larger than that of LCA. HENA failed to dilate the arteries from the KCNMB1 knockout mouse, underscoring BK beta 1's role in HENA action. Finally, carotid artery-infusion of HENA (45 mu M) dilated the pial cerebral arterioles via selective BK-channel targeting. In conclusion, we have identified for the first time a nonsteroidal agent that selectively activates beta 1-containing BK channels by targeting the steroid-sensing site in BK beta 1, rendering vasodilation.