喹啉相关的抗疟药与心脏毒性风险有关,特别是QT延长和QRS波增宽。与疟疾药物风险投资(MMV)合作,我们发现了用于治疗疟疾的新型纤支酶X(PMX)抑制剂。在麻醉的豚鼠(GP)中测试的第一个先导化合物引起了深刻的QRS加宽,尽管在标准膜片钳测定中表现出对NaV1.5介导的电流的弱抑制作用。要了解QRS扩展的潜在机制,以确定没有此类责任的其他化合物,我们建立了一组体外模型,包括CaV1.2,NaV1.5速率依赖性和NaV1.8膜片钳测定,人诱导多能干细胞来源的心肌细胞(hiPSC-CM),和Langendorff灌注的孤立GP心脏。在所有模型中测试了六种化合物,包括麻醉的GP,和8个额外的化合物仅在体外测试。在麻醉的GP和孤立的心脏中测试的所有化合物都显示出相似的心血管特征,包括QRS加宽,心动过缓,负各向异性,低血压,对一些人来说,QT延长。然而,观察到浓度-反应曲线从体外到体内GP数据的左移.当比较体外模型时,hiPSC-CM中钠峰幅度的降低与孤立心脏中QRS的增宽之间存在良好的一致性。膜片钳分析结果表明,用PMX抑制剂观察到的QRS扩展可能是多因素的,主要是由于NaV1.8和NaV1.5速率依赖性钠阻断和/或钙通道介导的机制。总之,使用一组不同的体外试验,早期降低QRS波增宽的风险,可以鉴定具有改善心脏安全性的新型PMX抑制剂.
Quinoline-related antimalarial drugs have been associated with cardiotoxicity risk, in particular QT prolongation and QRS complex widening. In collaboration with Medicines for Malaria Venture (MMV), we discovered novel plasmepsin X (PMX) inhibitors for malaria treatment. The first lead compounds tested in anesthetized guinea pigs (GP) induced profound QRS widening, although exhibiting weak inhibition of NaV1.5-mediated currents in standard patch clamp assays. To understand the mechanism(s) underlying QRS widening to identify further compounds devoid of such liability, we established a set of in vitro models including CaV1.2, NaV1.5 rate-dependence and NaV1.8 patch clamp assays, human induced pluripotent stem cell-derived cardiomyocytes (hiPSC-CM), and Langendorff-perfused isolated GP hearts. Six compounds were tested in all models including anesthetized GP, and 8 additional compounds were tested in vitro only. All compounds tested in anesthetized GP and isolated hearts showed a similar cardiovascular profile, consisting of QRS widening, bradycardia, negative inotropy, hypotension, and for some, QT prolongation. However, a left shift of the concentration-response curves was noted from in vitro to in vivo GP data. When comparing in vitro models, there was a good consistency between decrease in sodium spike amplitude in hiPSC-CM and QRS widening in isolated hearts. Patch clamp assay results showed that the QRS widening observed with PMX inhibitors is likely multifactorial, primarily due to NaV1.8 and NaV1.5 rate-dependent sodium blockade and/or calcium channel-mediated mechanisms. In conclusion, early de-risking of QRS widening using a set of different in vitro assays allowed to identify novel PMX inhibitors with improved cardiac safety profile.