Natural and synthetic modulators of SK (Kca2) potassium channels inhibit magnesium-dependent activity of the kinase-coupled cation channel TRPM7
Natural and synthetic modulators of SK (Kca2) potassium channels inhibit magnesium-dependent activity of the kinase-coupled cation channel TRPM7
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DOI：
10.1111/j.1476-5381.2012.01855.x
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发表时间：
2012-06-01
影响因子：
7.3
通讯作者：
Gudermann, T.
中科院分区：
文献类型：
--
作者：
Chubanov, V.;Mederos y Schnitzler, M.;Gudermann, T.
瞬时受体电位阳离子通道亚家族M成员7（TRPM 7）是一种双功能蛋白质，其包含与α-型蛋白激酶结构域连接的TRP离子通道片段。TRPM 7对细胞增殖和生长至关重要。TRPM 7功能的上调涉及缺氧神经元死亡、心脏纤维化和肿瘤细胞增殖。这项工作的目的是确定TRPM 7通道的无毒抑制剂，并评估阻断内源性TRPM 7电流对活细胞表型的影响。实验方法我们开发了一种基于水母发光蛋白生物发光的TRPM 7通道活性测定，并对通道抑制剂进行了假设驱动的筛选。确定的候选人进一步评估电生理和细胞生物学实验。关键结果TRPM 7电流被小电导Ca 2+激活的K+通道（KCa2.12.3; SK）通道的调节剂抑制，包括抗疟疾植物生物碱奎宁、CyPPA、地喹宁、NS 8593、SKA 31和UCL 1684。与其他TRP通道相比，最有效的化合物NS 8593（IC 50 1.6 μ M）特异性靶向TRPM 7，干扰TRPM 7通道的Mg 2+依赖性调节，并抑制培养细胞的运动性。NS 8593在HEK 293细胞、新鲜分离的平滑肌细胞、原代足细胞和心室肌细胞中表现出对天然TRPM 7样电流的完全和可逆阻断。结论和意义本研究揭示了TRPM 7和KCa 2.12.3通道的药理学特征的紧密重叠。NS 8593作为TRPM 7的负门控调节剂，非常适合研究内源性TRPM 7的功能特征和细胞作用。
BACKGROUND AND PURPOSE Transient receptor potential cation channel subfamily M member 7 (TRPM7) is a bifunctional protein comprising a TRP ion channel segment linked to an a-type protein kinase domain. TRPM7 is essential for proliferation and cell growth. Up-regulation of TRPM7 function is involved in anoxic neuronal death, cardiac fibrosis and tumour cell proliferation. The goal of this work was to identify non-toxic inhibitors of the TRPM7 channel and to assess the effect of blocking endogenous TRPM7 currents on the phenotype of living cells. EXPERIMENTAL APPROACH We developed an aequorin bioluminescence-based assay of TRPM7 channel activity and performed a hypothesis-driven screen for inhibitors of the channel. The candidates identified were further assessed electrophysiologically and in cell biological experiments. KEY RESULTS TRPM7 currents were inhibited by modulators of small conductance Ca2+-activated K+ channels (KCa2.12.3; SK) channels, including the antimalarial plant alkaloid quinine, CyPPA, dequalinium, NS8593, SKA31 and UCL 1684. The most potent compound NS8593 (IC50 1.6 mu M) specifically targeted TRPM7 as compared with other TRP channels, interfered with Mg2+-dependent regulation of TRPM7 channel and inhibited the motility of cultured cells. NS8593 exhibited full and reversible block of native TRPM7-like currents in HEK 293 cells, freshly isolated smooth muscle cells, primary podocytes and ventricular myocytes. CONCLUSIONS AND IMPLICATIONS This study reveals a tight overlap in the pharmacological profiles of TRPM7 and KCa2.12.3 channels. NS8593 acts as a negative gating modulator of TRPM7 and is well-suited to study functional features and cellular roles of endogenous TRPM7.