Screening of Transient Receptor Potential Canonical Channel Activators Identifies Novel Neurotrophic Piperazine Compounds
作者:Seishiro Sawamura、Masahiko Hatano、Yoshinori Takada、Kyosuke Hino、Tetsuya Kawamura、Jun Tanikawa、Hiroshi Nakagawa、Hideharu Hase、Akito Nakao、Mitsuru Hirano、Rachapun Rotrattanadumrong、Shigeki Kiyonaka、Masayuki X. Mori、Motohiro Nishida、Yaopeng Hu、Ryuji Inoue、Ryu Nagata、Yasuo Mori
DOI:10.1124/mol.115.102863
日期:2016.3
Transient receptor potential canonical (TRPC) proteins form Ca2+-permeable cation channels activated upon stimulation of metabotropic receptors coupled to phospholipase C. Among the TRPC subfamily, TRPC3 and TRPC6 channels activated directly by diacylglycerol (DAG) play important roles in brain-derived neurotrophic factor (BDNF) signaling, promoting neuronal development and survival. In various disease models, BDNF restores neurologic deficits, but its therapeutic potential is limited by its poor pharmacokinetic profile. Elucidation of a framework for designing small molecules, which elicit BDNF-like activity via TRPC3 and TRPC6, establishes a solid basis to overcome this limitation. We discovered, through library screening, a group of piperazine-derived compounds that activate DAG-activated TRPC3/TRPC6/TRPC7 channels. The compounds \[4-(5-chloro-2-methylphenyl)piperazin-1-yl\](3-fluorophenyl)methanone (PPZ1) and 2-[4-(2,3-dimethylphenyl)piperazin-1-yl]- N -(2-ethoxyphenyl)acetamide (PPZ2) activated, in a dose-dependent manner, recombinant TRPC3/TRPC6/TRPC7 channels, but not other TRPCs, in human embryonic kidney cells. PPZ2 activated native TRPC6-like channels in smooth muscle cells isolated from rabbit portal vein. Also, PPZ2 evoked cation currents and Ca2+ influx in rat cultured central neurons. Strikingly, both compounds induced BDNF-like neurite growth and neuroprotection, which were abolished by a knockdown or inhibition of TRPC3/TRPC6/TRPC7 in cultured neurons. Inhibitors of Ca2+ signaling pathways, except calcineurin, impaired neurite outgrowth promotion induced by PPZ compounds. PPZ2 increased activation of the Ca2+-dependent transcription factor, cAMP response element–binding protein. These findings suggest that Ca2+ signaling mediated by activation of DAG-activated TRPC channels underlies neurotrophic effects of PPZ compounds. Thus, piperazine-derived activators of DAG-activated TRPC channels provide important insights for future development of a new class of synthetic neurotrophic drugs.
瞬时感受器电位经典(TRPC)蛋白形成Ca2+可通透的阳离子通道,在代谢型受体激活磷脂酶C后被活化。在TRPC亚家族中,直接被甘油二酯(DAG)激活的TRPC3和TRPC6通道在脑源性神经营养因子(BDNF)信号通路中发挥重要作用,促进神经元发育和存活。在多种疾病模型中,BDNF可以恢复神经功能缺陷,但其治疗潜力受到其较差的药代动力学特性的限制。通过TRPC3和TRPC6激活BDNF样活性的小分子的设计框架的阐明,为克服这一限制提供了坚实的基础。我们通过筛选库发现了激活DAG激活的TRPC3/TRPC6/TRPC7通道的一组哌嗪衍生物。化合物\[4-(5-氯-2-甲基苯基)哌嗪-1-基\](3-氟苯基)甲酮(PPZ1)和2-[4-(2,3-二甲基苯基)哌嗪-1-基]- N -(2-乙氧基苯基)乙酰胺(PPZ2)在人胚胎肾细胞中剂量依赖性地激活重组的TRPC3/TRPC6/TRPC7通道,但不激活其他TRPC通道。PPZ2在从兔门静脉分离的平滑肌细胞中激活内源性TRPC6样通道。此外,PPZ2在培养的大鼠中枢神经元中诱发阳离子电流和Ca2+内流。值得注意的是,这两种化合物都诱导了类似于BDNF的神经突生长和神经保护作用,这些作用在培养的神经元中通过敲低或抑制TRPC3/TRPC6/TRPC7而被消除。除了钙调神经磷酸酶外,Ca2+信号通路的抑制剂会损害PPZ化合物诱导的神经突生长促进作用。PPZ2增加了Ca2+依赖性转录因子cAMP反应元件结合蛋白的激活。这些发现表明,通过激活DAG激活的TRPC通道介导的Ca2+信号传导是PPZ化合物产生神经营养效应的基础。因此,激活DAG激活的TRPC通道的哌嗪衍生物提供了重要洞见,为未来开发新型合成神经营养药物提供了新的方向。