Zhu Yingmin, Lu Yungang, Qu Chunrong, Miller Melissa, Tian Jinbin, Thakur Dhananjay P, Zhu Jinmei, Deng Zixin, Hu Xianming, Wu Meng, McManus Owen B, Li Min, Hong Xuechuan, Zhu Michael X, Luo Huai-Rong
Department of Integrative Biology and Pharmacology, The University of Texas Health Science Center at Houston, Houston, TX, USA.
The Third Affiliated Hospital of Guangzhou Medical University, Guangzhou, Guangdong, China.
Br J Pharmacol. 2015 Jul;172(14):3495-509. doi: 10.1111/bph.13140. Epub 2015 May 11.
Transient receptor potential canonical (TRPC) channels play important roles in a broad array of physiological functions and are involved in various diseases. However, due to a lack of potent subtype-specific inhibitors the exact roles of TRPC channels in physiological and pathophysiological conditions have not been elucidated.
Using fluorescence membrane potential and Ca(2+) assays and electrophysiological recordings, we characterized new 2-aminobenzimidazole-based small molecule inhibitors of TRPC4 and TRPC5 channels identified from cell-based fluorescence high-throughput screening.
The original compound, M084, was a potent inhibitor of both TRPC4 and TRPC5, but was also a weak inhibitor of TRPC3. Structural modifications of the lead compound resulted in the identification of analogues with improved potency and selectivity for TRPC4 and TRPC5 channels. The aminobenzimidazole derivatives rapidly inhibited the TRPC4- and TRPC5-mediated currents when applied from the extracellular side and this inhibition was independent of the mode of activation of these channels. The compounds effectively blocked the plateau potential mediated by TRPC4-containing channels in mouse lateral septal neurons, but did not affect the activity of heterologously expressed TRPA1, TRPM8, TRPV1 or TRPV3 channels or that of the native voltage-gated Na(+) , K(+) and Ca(2) (+) channels in dissociated neurons.
The TRPC4/C5-selective inhibitors developed here represent novel and useful pharmaceutical tools for investigation of physiological and pathophysiological functions of TRPC4/C5 channels.
瞬时受体电位香草酸亚家族（TRPC）通道在多种生理功能中发挥重要作用，并参与多种疾病的发生发展。然而，由于缺乏有效的亚型特异性抑制剂，TRPC通道在生理和病理生理条件下的确切作用尚未阐明。
我们利用荧光膜电位和Ca(2+)检测以及电生理记录，对通过基于细胞的荧光高通量筛选鉴定出的新型2-氨基苯并咪唑类TRPC4和TRPC5通道小分子抑制剂进行了表征。
原始化合物M084是TRPC4和TRPC5的有效抑制剂，但也是TRPC3的弱抑制剂。对先导化合物进行结构修饰后，鉴定出了对TRPC4和TRPC5通道具有更高活性和选择性的类似物。氨基苯并咪唑衍生物从细胞外施加时能迅速抑制TRPC4和TRPC5介导的电流，且这种抑制与这些通道的激活方式无关。这些化合物有效阻断了小鼠外侧隔核神经元中由含TRPC4通道介导的平台电位，但不影响异源表达的TRPA1、TRPM8、TRPV1或TRPV3通道的活性，也不影响解离神经元中天然电压门控Na(+)、K(+)和Ca(2+)通道的活性。
本文开发的TRPC4/C5选择性抑制剂是研究TRPC4/C5通道生理和病理生理功能的新型有用药物工具。
