Hydroxychloroquine induces long QT syndrome by blocking hERG channel

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.

Prevention and control measures of the major cold-region diseases (hypertension) in China

Hypertension is the most common cardiovascular condition in clinical practice and a major risk factor for stroke and cardiovascular events.There are more than 270 million hypertension patients in China,and the prevalence of hypertension in the high-latitude cold areas is significantly higher than in the low-latitude warm areas.The unique epidemiological characteristics and risk factors of hypertension in the cold regions of China urge for establishment of the prevention and control system for targeted and more effective management of the condition.

Ablation of apoptosis-stimulating of p53 protein 1 protects mice from acute hepatic injury and dysfunction via NF-κB pathway in CCl4-induced hepatotoxicity

Acute liver injury(ALI)is characterized by apoptosis,inflammation,and oxidative stress,and pathogenic mechanism of ALI is poorly understood.Apoptosis-stimulating of p53 protein 1(ASPP1)is involved in environmental responses,tumor growth,and NF-κB activity,which is of critical importance to ALI.However,the role of ASPP1 in ALI remains largely unexplored.The current study aimed to determine the role of ASPP1 in ALI induced by CCl4 and the underlying mechanism.ASPP1 expression was detected in wild type(WT)mice with ALI induced by CCl4.The function of ASPP1 in ALI induced by CCl4 was investigated using conventional knockout ASPP1 mice.ASPP1 expression significantly increased in ALI mice at 24 hours after CCl4 injection.Deletion of ASSP1 ameliorated apoptosis,inflammation,and necrosis in ALI relative to WT mice.In addition,deficiency of ASPP1 improved liver flood flow as well as ALT and AST levels.The levels of phosphorylated p65 and phosphorylated IκBαwere lower in ASPP1-/-mice than in WT mice with ALI.These results implicate that deletion of ASPP1 may act via inhibition of the NF-кB pathway and protect mice from ALI,which may be a new potential therapeutic target for the treatment of ALI.

LncDACH1 promotes mitochondrial oxidative stress of cardiomyocytes by interacting with sirtuin3 and aggravates diabetic cardiomyopathy

Diabetic cardiomyopathy(DCM)is a common complication in diabetic patients.The molecular mechanisms of DCM remain to be fully elucidated.The intronic long noncoding RNA of DACH1(lnc DACH1)has been demonstrated to be closely associated with heart failure and cardiac regeneration.In this study,we investigated the role of lnc DACH1 in DCM and the underlying molecular mechanisms.The expression of lnc DACH1 was increased in DCM hearts and in high glucose-treated cardiomyocytes.Knockout of lnc DACH1 reduced mitochondrial oxidative stress,cell apoptosis,cardiac fibrosis and hypertrophy,and improved cardiac function in DCM mice.Overexpression of lnc DACH1 exacerbated mitochondria-derived reactive oxygen species(ROS)level and apoptosis,decreased activity of manganese superoxide dismutase(Mn-SOD);while silencing of lnc DACH1 attenuated ROS production,mitochondrial dysfunction,cell apoptosis,and increased the activity of Mn-SOD in cardiomyocytes treated with high glucose.Lnc DACH1 directly bound to sirtuin3(SIRT3)and facilitated its degradation by ubiquitination,therefore promoting mitochondrial oxidative injury and cell apoptosis in mouse hearts.In addition,SIRT3 silencing abrogated the protective effects of lnc DACH1 deficiency in cardiomyocytes.In summary,lnc DACH1 aggravates DCM by promoting mitochondrial oxidative stress and cell apoptosis via increasing ubiquitination-mediated SIRT3 degradation in mouse hearts.Inhibition of lnc DACH1 represents a novel therapeutic strategy for the intervention of diabetic cardiomyopathy.