Department of Physiology, Faculty of Science, Mahidol University, Rajathevi, Bangkok, 10400, Thailand; Chakri Naruebodindra Medical Institute, Faculty of Medicine Ramathibodi Hospital, Mahidol University, Bang Phli, Samut Prakarn, 10540, Thailand.
Chakri Naruebodindra Medical Institute, Faculty of Medicine Ramathibodi Hospital, Mahidol University, Bang Phli, Samut Prakarn, 10540, Thailand.
Eur J Pharmacol. 2020 Oct 15;885:173393. doi: 10.1016/j.ejphar.2020.173393. Epub 2020 Jul 23.
Secretory diarrhea is one of the most common types of diarrhea with high morbidity and mortality. Previous studies showed that inhibition of cystic fibrosis transmembrane conductance regulator (CFTR) Cl channels alleviated fluid loss in secretory diarrheas. This study aimed to identify novel CFTR inhibitors from fungal metabolites and explore its underlying mechanisms and potential utility in secretory diarrheas. Electrophysiological analyses in human intestinal epithelial (T84) cells were performed to investigate the effect and mechanism of fungal metabolites on CFTR-mediated Cl secretion. Anti-diarrheal efficacy and the effect of compound on fluid absorption were investigated in mouse closed-loop models. We found that the screening identified arthropsolide A, a fungal metabolite from an endophytic fungus Roussoella sp. PSU-H51, as an inhibitor of CFTR-mediated Cl secretion in T84 cells (IC ~0.8 μM). Arthropsolide A inhibited both CFTR and cAMP-activated basolateral K channels. Arthropsolide A had no effect on Na-K ATPase activity. Interestingly, the inhibitory effect of arthropsolide A on CFTR was attenuated by cell depolarization and AMPK inhibition independent of multi-drug resistance protein 4, phosphodiesterases, and protein phosphatases. Importantly, arthropsolide A suppressed cholera toxin (CT)-induced Cl secretion in T84 cells and CT-induced intestinal fluid secretion in mice by ~75% without affecting intestinal fluid absorption. Taken together, arthropsolide A represents a novel class of fungal metabolites that acts as a potent CFTR inhibitor. Further development of this class of compounds may provide a therapy for secretory diarrheas.
分泌性腹泻是最常见的腹泻类型之一，发病率和死亡率都很高。先前的研究表明，囊性纤维化跨膜电导调节因子（CFTR）Cl 通道的抑制可减轻分泌性腹泻中的液体流失。本研究旨在从真菌代谢产物中鉴定新型 CFTR 抑制剂，并探讨其在分泌性腹泻中的潜在机制和应用。在人肠上皮（T84）细胞中进行电生理学分析，以研究真菌代谢产物对 CFTR 介导的 Cl 分泌的作用和机制。在小鼠闭路模型中研究了化合物的抗腹泻功效和对液体吸收的影响。我们发现，筛选出的arthropsolide A 是一种来自内生真菌 Roussoella sp. PSU-H51 的真菌代谢产物，是 T84 细胞中 CFTR 介导的 Cl 分泌的抑制剂（IC ~0.8 μM）。arthropsolide A 抑制 CFTR 和 cAMP 激活的基底外侧 K 通道。arthropsolide A 对 Na-K ATPase 活性没有影响。有趣的是，arthropsolide A 对 CFTR 的抑制作用可被细胞去极化和 AMPK 抑制减弱，与多药耐药蛋白 4、磷酸二酯酶和蛋白磷酸酶无关。重要的是，arthropsolide A 抑制霍乱毒素（CT）诱导的 T84 细胞 Cl 分泌和 CT 诱导的小鼠肠道液体分泌，抑制率约为 75%，而不影响肠道液体吸收。总之，arthropsolide A 代表了一类新型的真菌代谢产物，可作为一种有效的 CFTR 抑制剂。进一步开发这类化合物可能为分泌性腹泻提供一种治疗方法。
