Investigating the effect of Shenmai injection on cardiac electrophysiology and calcium signaling using human-induced pluripotent stem cell-derived cardiomyocytes.

Traditional Chinese medicine injection (TCMI) refers to the use of modern technology to make Chinese patent medicines in injectable forms, which shorten the onset time of the traditional Chinese medicine (TCM). Although there have been clinical cases in which Shenmai injection (SMI) was used to treat cardiovascular diseases (CVDs), there are no pharmacological experiments that investigate the efficacy of the drug in vitro or the underlying mechanisms. Aim of the study: We aimed to systemically evaluate the efficacy and investigate the mechanisms of SMI in modulating electrophysiology and calcium (Ca2+) signaling using a microelectrode array (MEA) and a genetically encoded Ca2+ indicator, GCaMP6s, respectively, in human-induced pluripotent stem cell-derived cardiomyocytes (hiPSC-CMs). Materials and methods: A MEA system was employed to record field potentials (FPs) in hiPSC-CMs. The QT interval is corrected by the RR interval, the reciprocal of the beating rate. GCaMP6s was used to measure Ca2+ signaling in hiPSC-CMs. Meanwhile, the transcriptome changes in hiPSC-CMs treated with 2% SMI were examined using RNAseq. In addition, the ingredients of SMI were investigated using liquid chromatography-mass spectrometry (LC-MS). Results: It was found that 0.5%, 1%, and 2% (v/v) SMIs could increase corrected QT (QTc) but did not change other FP parameters. GCaMP6s was successfully applied to measure the chronic function of SMI. The full width at half maximum (FWHM), rise time, and decay time significantly decreased after treatment with SMI for 1 h and 24 h, whereas an increased Ca2+ transient frequency was observed. Conclusions: We first used the Ca2+ indicator to measure the chronic effects of TCM. We found that SMI treatment can modulate electrophysiology and calcium signaling and regulate oxidative phosphorylation, cardiac muscle contraction, and the cell cycle pathway in hiPSC-CMs.

Analysis of signal components < 500 Hz in brain organoids coupled to microelectrode arrays: A reliable test-bed for preclinical seizure liability assessment of drugs and screening of antiepileptic drugs.

Brain organoids with three-dimensional structure and tissue-like function are highly demanded for brain disease research and drug evaluation. However, to our knowledge, methods for measuring and analyzing brain organoid function have not been developed yet. This study focused on the frequency components of an obtained waveform below 500 Hz using planner microelectrode array (MEA) and evaluated the response to the convulsants pentylenetetrazol (PTZ) and strychnine as well as the antiepileptic drugs (AEDs) perampanel and phenytoin. Sudden and persistent seizure-like firing was observed with PTZ administration, displaying a concentration-dependent periodic activity with the frequency component enhanced even in one oscillation characteristic. On the other hand, in the administration of AEDs, the frequency of oscillation decreased in a concentration-dependent manner and the intensity of the frequency component in one oscillation also decreased. Interestingly, at low doses of phenytoin, a group of synchronized bursts was formed, which was different from the response to the perampanel. Frequency components contained information on cerebral organoid function, and MEA was proven useful in predicting the seizure liability of drugs and evaluating the effect of AEDs with a different mechanism of action. In addition, frequency component analysis of brain organoids using MEA is an important analysis method to perform in vitro to in vivo extrapolation in the future, which will help explore the function of the organoid itself, study human brain developments, and treat various brain diseases.