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Hydroxychloroquine induces long QT syndrome by blocking hERG channel
Xin Zhao, Lihua Sun, Chao Chen, Jieru Xin, Yan Zhang, Yunlong Bai, Zhenwei Pan, Yong Zhang, Baoxin Li, Yanjie Lv, Baofeng Yang
2023, 3(2): 105-113. doi: 10.2478/fzm-2023-0014
Keywords: COVID-19, hydroxychloroquine, LQT, hERG, Hsp90
  Objective  In March 2022, more than 600 million cases of Corona Virus Disease 2019 (COVID-19) and about 6 million deaths have been reported worldwide. Unfortunately, while effective antiviral therapy has not yet been available, chloroquine (CQ)/hydroxychloroquine (HCQ) has been considered an option for the treatment of COVID-19. While many studies have demonstrated the potential of HCQ to decrease viral load and rescue patients' lives, controversial results have also been reported. One concern associated with HCQ in its clinical application to COVID-19 patients is the potential of causing long QT interval (LQT), an electrophysiological substrate for the induction of lethal ventricular tachyarrhythmias. Yet, the mechanisms for this cardiotoxicity of HCQ remained incompletely understood.  Materials and methods  Adult New Zealand white rabbits were used for investigating the effects of HCQ on cardiac electrophysiology and expression of ion channel genes. HEK-293T cells with sustained overexpression of human-ether-a-go-go-related gene (hERG) K+ channels were used for whole-cell patch-clamp recordings of hERG K+ channel current (IhERG). Quantitative RT-PCR analysis and Western blot analysis were employed to determine the expression of various genes at mRNA and protein levels, respectively.  Results  electrocardiogram (ECG) recordings revealed that HCQ prolonged QT and RR intervals and slowed heart rate in rabbits. Whole-cell patch-clamp results showed that HCQ inhibited the tail current of hERG channels and slowed the reactivation process from inactivation state. HCQ suppressed the expression of hERG and hindered the formation of the heat shock protein 90 (Hsp90)/hERG complex. Moreover, the expression levels of connexin 43 (CX43) and Kir2.1, the critical molecular/ionic determinants of cardiac conduction thereby ventricular arrythmias, were decreased by HCQ, while those of Cav1.2, the main Ca2+ handling proteins, remained unchanged and SERCA2a was increased.  Conclusion  HCQ could induce LQT but did not induce arrhythmias, and whether it is suitable for the treatment of COVID-19 requires more rigorous investigations and validations in the future.
Ethanol extract of cassia seed alleviates metabolic dysfunction-associated steatotic liver disease by acting on multiple lipid metabolism-related pathways
Wen Li, Jia Wang, Yilian Yang, Chunlei Duan, Bing Shao, Mingxiu Zhang, Jiapan Wang, Peifeng Li, Ye Yuan, Yan Zhang, Hongyu Ji, Xingda Li, Zhimin Du
2024, 4(3): 160-176. doi: 10.1515/fzm-2024-0017
Keywords: cassia seed ethanol extract, metabolic dysfunction related fatty liver disease, network pharmacology
  Background and objective  In northern China's cold regions, the prevalence of metabolic dysfunction-associated steatotic liver disease (MASLD) exceeds 50%, significantly higher than the national and global rates. MASLD is an important risk factor for cardiovascular and cerebrovascular diseases, including coronary heart disease, stroke, and tumors, with no specific therapeutic drugs currently available. The ethanol extract of cassia seed (CSEE) has shown promise in lowering blood lipids and improving hepatic steatosis, but its mechanism in treating MASLD remains underexplored. This study aims to investigate the therapeutic effects and mechanisms of CSEE.  Methods  MASLD models were established in male Wistar rats and golden hamsters using a high fat diet (HFD). CSEE (10, 50, 250 mg/kg) was administered via gavage for six weeks. Serum levels of total cholesterol (TC), triglyceride (TG), lowdensity lipoprotein cholesterol (LDL-C), high-density lipoprotein cholesterol (HDL-C), aspartate aminotransferase (AST), and alanine aminotransferase (ALT), as well as liver TC and TG, were measured using biochemical kits. Histopathological changes in the liver were evaluated using Oil Red O staining, Hematoxylin-eosin (H&E) staining, and transmission electron microscopy (TEM). HepG2 cell viability was assessed using the cell counting kit-8 (CCK8) and Calcein-AM/PI staining. Network pharmacology was used to analyze drug-disease targets, and western blotting was used to confirm these predictions.  Results  CSEE treatment significantly reduced serum levels of TC, TG, LDL-C, ALT, and AST, and improved liver weight, liver index, and hepatic lipid deposition in rats and golden hamsters. In addition, CSEE alleviated free fatty acid (FFA)-induced lipid deposition in HepG2 cells. Molecular biology experiments demonstrated that CSEE increased the protein levels of p-AMPK, p-ACC, PPARα, CPT1A, PI3K P110 and p-AKT, while decreasing the protein levels of SREBP1, FASN, C/EBPα, and PPARγ, thus improving hepatic lipid metabolism and reducing lipid deposition. The beneficial effects of CSEE were reversed by small molecule inhibitors of the signaling pathways in vitro.  Conclusion  CSEE improves liver lipid metabolism and reduces lipid droplet deposition in Wistar rats and golden hamsters with MASLD by activating hepatic AMPK, PPARα, and PI3K/AKT signaling pathways.