Abstract
Pancreatic K(ATP) channel trafficking defects underlie congenital hyperinsulinism (CHI) cases unresponsive to the K(ATP) channel opener diazoxide, the mainstay medical therapy for CHI. Current clinically used K(ATP) channel inhibitors have been shown to act as pharmacochaperones and restore surface expression of trafficking mutants; however, their therapeutic utility for K(ATP) trafficking-impaired CHI is hindered by high affinity binding, which limits functional recovery of rescued channels. Recent structural studies of K(ATP) channels employing cryo-electron microscopy (cryoEM) have revealed a promiscuous pocket where several known K(ATP) pharmacochaperones bind. The structural knowledge provides a framework for discovering K(ATP) 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(ATP) channel trafficking mutations. Aekatperone reversibly inhibits K(ATP) channel activity with a half-maximal inhibitory concentration (IC(50)) ~9 μM. Mutant channels rescued to the cell surface by Aekatperone showed functional recovery upon washout of the compound. CryoEM structure of K(ATP) bound to Aekatperone revealed distinct binding features compared to known high affinity inhibitor pharmacochaperones. Our findings unveil a K(ATP) pharmacochaperone enabling functional recovery of rescued channels as a promising therapeutic for CHI caused by K(ATP) trafficking defects.