ElSheikh Assmaa, Driggers Camden M, Truong Ha H, Yang Zhongying, Allen John, Henriksen Niel, Walczewska-Szewc Katarzyna, Shyng Show-Ling
Department of Chemical Physiology and Biochemistry, Oregon Health & Science University, Portland, OR 97239, USA.
Department of Medical Biochemistry, College of Medicine, Tanta University, Tanta, Egypt.
bioRxiv. 2025 Feb 7:2024.09.05.611490. doi: 10.1101/2024.09.05.611490.
Pancreatic K channel trafficking defects underlie congenital hyperinsulinism (CHI) cases unresponsive to the K channel opener diazoxide, the mainstay medical therapy for CHI. Current clinically used K channel inhibitors have been shown to act as pharmacochaperones and restore surface expression of trafficking mutants; however, their therapeutic utility for K trafficking impaired CHI is hindered by high-affinity binding, which limits functional recovery of rescued channels. Recent structural studies of K channels employing cryo-electron microscopy (cryoEM) have revealed a promiscuous pocket where several known K pharmacochaperones bind. The structural knowledge provides a framework for discovering K channel pharmacochaperones with desired reversible inhibitory effects to permit functional recovery of rescued channels. Using an AI-based virtual screening technology AtomNet followed by functional validation, we identified a novel compound, termed Aekatperone, which exhibits chaperoning effects on K channel trafficking mutations. Aekatperone reversibly inhibits K channel activity with a half-maximal inhibitory concentration (IC) ~ 9 μM. Mutant channels rescued to the cell surface by Aekatperone showed functional recovery upon washout of the compound. CryoEM structure of K bound to Aekatperone revealed distinct binding features compared to known high affinity inhibitor pharmacochaperones. Our findings unveil a K pharmacochaperone enabling functional recovery of rescued channels as a promising therapeutic for CHI caused by K trafficking defects.
胰腺钾通道转运缺陷是先天性高胰岛素血症（CHI）病例中对钾通道开放剂二氮嗪无反应的基础，二氮嗪是CHI的主要药物治疗方法。目前临床上使用的钾通道抑制剂已被证明可作为药物伴侣并恢复转运突变体的表面表达；然而，它们对钾转运受损的CHI的治疗效用受到高亲和力结合的阻碍，这限制了挽救通道的功能恢复。最近采用冷冻电子显微镜（cryoEM）对钾通道进行的结构研究揭示了一个杂乱的口袋，几种已知的钾药物伴侣结合在那里。该结构知识为发现具有所需可逆抑制作用的钾通道药物伴侣提供了框架，以允许挽救通道的功能恢复。使用基于人工智能的虚拟筛选技术AtomNet并随后进行功能验证，我们鉴定出一种新型化合物，称为Aekatperone，它对钾通道转运突变具有伴侣作用。Aekatperone以半最大抑制浓度（IC）~9μM可逆地抑制钾通道活性。通过Aekatperone挽救到细胞表面的突变通道在洗脱该化合物后显示出功能恢复。与已知的高亲和力抑制剂药物伴侣相比，与Aekatperone结合的钾通道的冷冻电子显微镜结构显示出不同的结合特征。我们的研究结果揭示了一种钾药物伴侣，它能够使挽救通道的功能恢复，作为由钾转运缺陷引起的CHI的一种有前途的治疗方法。
