Smooth muscle cell alpha2delta-1 subunits are essential for vasoregulation by CaV1.2 channels.
Smooth muscle cell alpha2delta-1 subunits are essential for vasoregulation by CaV1.2 channels.
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DOI：
10.1161/circresaha.109.203620
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发表时间：
2009-11-06
影响因子：
20.1
通讯作者：
Jaggar JH
中科院分区：
文献类型：
--
作者：
Bannister JP;Adebiyi A;Zhao G;Narayanan D;Thomas CM;Feng JY;Jaggar JH
电压依赖性 L 型 (CaV1.2) Ca2+ 通道是由孔形成 α1 和辅助 α2δ 和 β 亚基形成的异聚复合物。 CaV1.2 通道是动脉肌细胞中主要的 Ca2+ 流入途径，调节多种生理功能，包括收缩。动脉肌细胞 CaV1.2 通道的大分子组成仍然知之甚少，没有研究检查 α2δ 亚基的分子特性或生理功能。研究阻力大小（直径 100-200 μm）脑动脉肌细胞中 α2δ 亚基的功能意义。 α2δ-1是脑动脉肌细胞中唯一表达的α2δ亚型。普瑞巴林（一种 α2δ-1/-2 配体）和一种 α2δ-1 抗体可抑制分离心肌细胞中的 CaV1.2 电流。急性普瑞巴林应用可逆性扩张加压动脉。使用表面生物素化的新应用，数据表明 >95% 的 CaV1.2 α1 和 α2δ-1 亚基存在于动脉肌细胞质膜中。使用 shRNA 敲除 α2δ-1 可减少质膜定位的 CaV1.2 α1 亚基，导致胞质 CaV1.2 α1 亚基相应升高，降低细胞内 Ca2+ 浓度，抑制压力诱导的血管收缩（“肌源性张力”），并减弱普瑞巴林诱导的血管舒张。延长（24 小时）普瑞巴林暴露不会改变总 α2δ-1 或 CaV1.2 α1 蛋白，但会降低每个亚基的质膜表达，从而降低肌源性张力。 α2δ-1 对于动脉肌细胞 CaV1.2 α1 亚基的质膜表达至关重要。 α2δ-1靶向可直接阻断CaV1.2通道并抑制CaV1.2 α1亚基的表面表达，导致血管舒张。这些数据将 α2δ-1 确定为动脉肌细胞中的新分子靶标，对其进行调控可调节收缩性。
Voltage-dependent L-type (CaV1.2) Ca2+ channels are a heteromeric complex formed from pore forming α1 and auxiliary α2δ and β subunits. CaV1.2 channels are the principal Ca2+ influx pathway in arterial myocytes and regulate multiple physiological functions, including contraction. The macromolecular composition of arterial myocyte CaV1.2 channels remains poorly understood, with no studies having examined the molecular identity or physiological functions of α2δ subunits. Investigate the functional significance of α2δ subunits in myocytes of resistance-size (100–200 μm diameter) cerebral arteries. α2δ-1 was the only α2δ isoform expressed in cerebral artery myocytes. Pregabalin, an α2δ-1/-2 ligand, and an α2δ-1 antibody, inhibited CaV1.2 currents in isolated myocytes. Acute pregabalin application reversibly dilated pressurized arteries. Using a novel application of surface biotinylation, data indicated that >95 % of CaV1.2 α1 and α2δ-1 subunits are present in the arterial myocyte plasma membrane. α2δ-1 knockdown using shRNA reduced plasma membrane-localized CaV1.2 α1 subunits, caused a corresponding elevation in cytosolic CaV1.2 α1 subunits, decreased intracellular Ca2+ concentration, inhibited pressure-induced vasoconstriction (“myogenic tone”), and attenuated pregabalin-induced vasodilation. Prolonged (24 hour) pregabalin exposure did not alter total α2δ-1 or CaV1.2 α1 proteins, but decreased plasma membrane expression of each subunit, which reduced myogenic tone. α2δ-1 is essential for plasma membrane expression of arterial myocyte CaV1.2 α1 subunits. α2δ-1 targeting can block CaV1.2 channels directly and inhibit surface expression of CaV1.2 α1 subunits, leading to vasodilation. These data identify α2δ-1 as a novel molecular target in arterial myocytes, manipulation of which regulates contractility.