title: L-Type Calcium Channel Inhibition Contributes to the Proarrhythmic Effects of Aconitine in Human Cardiomyocytes.
abstract: Aconitine (ACO) is well-known for causing lethal ventricular tachyarrhythmias. While cardiac Na+ channel opening during repolarization has long been documented in animal cardiac myocytes, the cellular effects and mechanism of ACO in human remain unexplored. This study aimed to assess the proarrhythmic effects of ACO in human induced pluripotent stem cell-derived cardiomyocytes (hiPSC-CMs). ACO concentration-dependently (0.3 ~ 3.0 μM) shortened the action potentials (AP) durations (APD) in ventricular-like hiPSC-CMs by > 40% and induced delayed after-depolarization. Laser-scanning confocal calcium imaging analysis showed that ACO decreased the duration and amplitude of [Ca2+]i transients and increased in the beating frequencies by over 60%. Moreover, ACO was found to markedly reduce the L-type calcium channel (LTCC) currents (ICa,L) in hiPSC-CMs associated with a positive-shift of activation and a negative shift of inactivation. ACO failed to alter the peak and late Na+ currents (INa) in hiPSC-CMs while it drastically increased the late INa in Guinea-pig ventricular myocytes associated with enhanced activation/delayed inactivation of INa at -55 mV~ -85 mV. Further, the effects of ACO on ICa,L, INa and the rapid delayed rectifier potassium current (Ikr) were validated in heterologous expression systems by automated voltage-clamping assays and a moderate suppression of Ikr was observed in addition to concentration-dependent ICa,L inhibition. Lastly, increased beating frequency, decreased Ca2+ wave and shortened field potential duration were recorded from hiPSC-CMs by microelectrode arrays assay. In summary, our data demonstrated that LTCC inhibition could play a main role in the proarrhythmic action of ACO in human cardiomyocytes.
authors.affiliation: National Heart Research Institute Singapore, National Heart Centre Singapore, Singapore.
authors.forename: Jianjun
authors.initials: J
authors.lastname: Wu
authors.affiliation: Department of Pharmacology, Hebei Medical University, Shijiazhuang, Hebei, China.
authors.forename: Xiangchong
authors.initials: X
authors.lastname: Wang
authors.affiliation: National Heart Research Institute Singapore, National Heart Centre Singapore, Singapore.
authors.forename: Ying Ying
authors.initials: YY
authors.lastname: Chung
authors.affiliation: National Heart Research Institute Singapore, National Heart Centre Singapore, Singapore.
authors.forename: Cai Hong
authors.initials: CH
authors.lastname: Koh
authors.affiliation: National Heart Research Institute Singapore, National Heart Centre Singapore, Singapore.
authors.forename: Zhenfeng
authors.initials: Z
authors.lastname: Liu
authors.affiliation: Department of Toxicology, Hebei Medical University, Shijiazhuang, Hebei, China.
authors.forename: Huicai
authors.initials: H
authors.lastname: Guo
authors.affiliation: Neuroscience & Behavioral Disorders Program, Duke-NUS Medical School Singapore, Singapore.
authors.forename: Qiang
authors.initials: Q
authors.lastname: Yuan
authors.affiliation: Department of Pharmacology, Hebei Medical University, Shijiazhuang, Hebei, China.
authors.forename: Chuan
authors.initials: C
authors.lastname: Wang
authors.affiliation: Department of Pharmacology, Hebei Medical University, Shijiazhuang, Hebei, China.
authors.forename: Suwen
authors.initials: S
authors.lastname: Su
authors.affiliation: National Heart Research Institute Singapore, National Heart Centre Singapore, Singapore.|Cardiovascular & Metabolic Disorders Program, Duke-NUS Medical School Singapore, Singapore.
authors.forename: Heming
authors.initials: H
authors.lastname: Wei
mesh_terms: D000157:Aconitine / Q000633:toxicity*; D000200:Action Potentials / Q000187:drug effects; D000818:Animals; D020746:Calcium Channels, L-Type / Q000378:metabolism*; D002478:Cells, Cultured; D006168:Guinea Pigs; D006801:Humans; D057026:Induced Pluripotent Stem Cells / Q000378:metabolism; D018613:Microscopy, Confocal; D032383:Myocytes, Cardiac / Q000187:drug effects* / Q000378:metabolism*; D018408:Patch-Clamp Techniques
chemical_list: D020746:Calcium Channels, L-Type; D000157:Aconitine