School of Life Sciences, Liaoning Provincial Key Laboratory of Biotechnology and Drug Discovery, Liaoning Normal University, Dalian 116081, PR China.
College of Basic Medical Sciences, Dalian Medical University, Dalian 116044, PR China.
Fitoterapia. 2020 Nov;147:104736. doi: 10.1016/j.fitote.2020.104736. Epub 2020 Sep 30.
Calcium-activated chloride channels (CaCCs) as a kind of widely expressed ion channels play crucial roles in a variety of physiological regulation. TMEM16A has been identified as the molecular basis of CaCCs in numerous cell types and is considered a new drug target for many diseases. Regulating the function of TMEM16A through small molecule modulators has become a new strategy to improve respiratory and digestive dysfunction and even tumor therapy. Herein, we obtained 5 sesquiterpenoids, named curzerenone, curdione, furanodienone, curcumol and germacrone with TMEM16A inhibition and revealed their mechanism of action by fluorescent and electrophysiological assays. Cell-based YFP fluorescence data demonstrated that 5 compounds inhibited TMEM16A-mediated I influx in a dose-dependent manner. To explore the mechanism of 5 compounds on CaCCs, FRT cells with high expression of TMEM16A, HBE, HT-29 and T84 cells and mouse colons were used in short-circuit current assay. Our results showed that 5 compounds inhibited the Ca-activated Cl currents generated by the E, ATP and UTP stimulation, and this inhibitory effect was related not only to the direct inhibition of channel opening, but also the inhibition of intracellular Ca concentration and K channel activity. In addition to CaCCs, these 5 compounds also had definite inhibitory activities against cystic fibrosis transmembrane regulator (CFTR) at the cellular level. In summary, these compounds have the potential to regulate the activites of TMEM16A/CaCCs and CFTR channels in vitro, providing a new class of lead compounds for the development of drugs for diseases related to chloride channel dysfunction.
钙激活氯离子通道（CaCCs）作为一种广泛表达的离子通道，在多种生理调节中起着关键作用。TMEM16A 已被确定为多种细胞类型中 CaCCs 的分子基础，被认为是许多疾病的新药物靶点。通过小分子调节剂调节 TMEM16A 的功能已成为改善呼吸和消化功能障碍甚至肿瘤治疗的新策略。在此，我们获得了 5 种倍半萜类化合物，分别命名为 curzerenone、curdione、furanodienone、curcumol 和 germacrone，它们具有 TMEM16A 抑制作用，并通过荧光和电生理测定揭示了它们的作用机制。基于细胞的 YFP 荧光数据表明，这 5 种化合物以剂量依赖的方式抑制 TMEM16A 介导的 I 内流。为了探讨 5 种化合物对 CaCCs 的作用机制，我们使用高表达 TMEM16A 的 FRT 细胞、HBE、HT-29 和 T84 细胞以及小鼠结肠进行了短电流电流测定。结果表明，这 5 种化合物抑制了 E、ATP 和 UTP 刺激产生的 Ca 激活的 Cl 电流，这种抑制作用不仅与通道开放的直接抑制有关，还与细胞内 Ca 浓度和 K 通道活性的抑制有关。除了 CaCCs 之外，这 5 种化合物在细胞水平上对囊性纤维化跨膜转导调节因子（CFTR）也具有一定的抑制活性。总之，这些化合物在体外具有调节 TMEM16A/CaCCs 和 CFTR 通道活性的潜力，为开发与氯离子通道功能障碍相关疾病的药物提供了一类新的先导化合物。
