Fenamates as TRP channel blockers: mefenamic acid selectively blocks TRPM3
Fenamates as TRP channel blockers: mefenamic acid selectively blocks TRPM3
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DOI：
10.1111/j.1476-5381.2010.01186.x
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发表时间：
2011-04-01
影响因子：
7.3
通讯作者：
Harteneck, Christian
中科院分区：
文献类型：
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作者：
Klose, Chihab;Straub, Isabelle;Harteneck, Christian
背景和目的非那酯是N-苯基取代的邻氨基苯甲酸衍生物，临床上用作非类固醇抗炎药治疗疼痛。由于我们对体积调节瞬时受体电位(Trp)通道TRPM3和TRPV4的作用感兴趣，所以将其描述为干扰细胞体积调节的工具的报道引起了我们的注意。首先，我们在异种HEK293细胞系统中用钙成像技术测量了异种HEK293细胞系统中氰甲酸酯对TRPM3和TRPV4以及TRPC6和TRPM2的阻断能力和选择性。其次，我们进一步研究了甲芬那酸对外源表达TRPM3的单个HEK293细胞内钙离子浓度和膜电压的影响。第三，在内源性表达TRPM3的胰岛素分泌INS-1E细胞中，我们验证了甲芬那酸对细胞内钙离子和胰岛素分泌的影响。结果甲芬那酸是一种选择性和有效的TRPM3阻断剂，而甲芬那酸的其他结构非选择性地阻断TRPM3、TRPV4、TRPC6和TRPM2。结论本研究表明甲芬那酸选择性地抑制TRPM3介导的钙内流。使用胰岛素分泌细胞进一步证实了这种选择性。甲非那酸不能阻断K(ATP)通道依赖性的胞浆Ca(2+)和胰岛素分泌的增加，但可抑制孕烯醇酮硫酸盐对依赖TRPM3的Ca(2+)内流和胰岛素分泌的选择性刺激。然而，TRPM3在胰岛素分泌细胞中的生理调节机制以及抑制TRPM3可能损害胰岛β细胞功能的条件仍有待阐明。我们的结果有力地表明甲芬那酸是最有选择性的干扰TRPM3功能的甲芬酸酯。
BACKGROUND AND PURPOSEFenamates are N-phenyl-substituted anthranilic acid derivatives clinically used as non-steroid anti-inflammatory drugs in pain treatment. Reports describing fenamates as tools to interfere with cellular volume regulation attracted our attention based on our interest in the role of the volume-modulated transient receptor potential (TRP) channels TRPM3 and TRPV4.EXPERIMENTAL APPROACHFirstly, we measured the blocking potencies and selectivities of fenamates on TRPM3 and TRPV4 as well as TRPC6 and TRPM2 by Ca(2+) imaging in the heterologous HEK293 cell system. Secondly, we further investigated the effects of mefenamic acid on cytosolic Ca(2+) and on the membrane voltage in single HEK293 cells that exogenously express TRPM3. Thirdly, in insulin-secreting INS-1E cells, which endogenously express TRPM3, we validated the effect of mefenamic acid on cytosolic Ca(2+) and insulin secretion.KEY RESULTSWe identified and characterized mefenamic acid as a selective and potent TRPM3 blocker, whereas other fenamate structures non-selectively blocked TRPM3, TRPV4, TRPC6 and TRPM2.CONCLUSIONS AND IMPLICATIONSThis study reveals that mefenamic acid selectively inhibits TRPM3-mediated calcium entry. This selectivity was further confirmed using insulin-secreting cells. K(ATP) channel-dependent increases in cytosolic Ca(2+) and insulin secretion were not blocked by mefenamic acid, but the selective stimulation of TRPM3-dependent Ca(2+) entry and insulin secretion induced by pregnenolone sulphate were inhibited. However, the physiological regulator of TRPM3 in insulin-secreting cells remains to be elucidated, as well as the conditions under which the inhibition of TRPM3 can impair pancreatic beta-cell function. Our results strongly suggest mefenamic acid is the most selective fenamate to interfere with TRPM3 function.