最近研究表明hERG(human ether-a—go-go related gene)基因编码的钾离子通道(hERG通道)作为一种广谱的药物靶标,被某些药物作用时会引起长QT间期综合征(LQTS),甚至导致具有生命危险的室性心律失常——尖端扭转性室性心动过速(TdP),引...最近研究表明hERG(human ether-a—go-go related gene)基因编码的钾离子通道(hERG通道)作为一种广谱的药物靶标,被某些药物作用时会引起长QT间期综合征(LQTS),甚至导致具有生命危险的室性心律失常——尖端扭转性室性心动过速(TdP),引起制药公司和安全部门的广泛关注,现就hERG通道的结构和功能特征、不同亚基及细胞环境对其调节、目前临床前体内体外的研究方法及关于hERG通道的药物安全性评价进行简要介绍。展开更多
The role of human ether a-go-go related gene(hERG) in electrically excitable cells has long been known.hERG currents IKr contribute to the re-polarisation phase 3 of the cardiac action potential. Mutations of this cha...The role of human ether a-go-go related gene(hERG) in electrically excitable cells has long been known.hERG currents IKr contribute to the re-polarisation phase 3 of the cardiac action potential. Mutations of this channel causes long QT syndrome. N629D hERG mutation(GFGN to GFGD) alters the pore selectivity signature sequence.N629D was over-expressed, via adenoviral gene transfer,in car-diomyocytes derived from mouse embryonic stem cells,the "IKr" showed outward rectification and an inward tail current,while WT IKr showed inward rectification and a positive tail current.N629D "IKr" phenotype also altered resting membrane potential and caused arrhythmia.Since hERG was reported to express in early stage of cardiogenesis,the role of the ERG potassium channel in cardiac development was elaborated in an in vivo model of a homozygous. The hERG N629D mutation was introduced into the orthologous mouse gene,mERG,by homologous recombination in mouse embryonic stem cells. N629D/N629D homozygous mutation results in embryonic lethality(died by E11.5).The mutation displayed defect cardiac morphogenesis including altered looping architecture,poorly developed bulbus cordis,and distorted aortic sac and branchial arches. N629D/N629D myocytes from embryonic day 9.5 embryos manifested complete loss of IKr function, depolarized resting potential,prolonged action potential duration(LQT),failure to repolarize,and propensity to oscillatory arrhythmias.Because deletion of transcription factor Hand2 produces apoptosis in similar regions and with a similar final developmental phenotype,Hand2 expression was evaluated. Robust decrease in Hand2 expression was observed in the secondary heart field in N629D/N629D embryos. mERG protein expression in the developing embryonic heart is not homogeneous.The protein expression is exaggerated in the right ventricle and in the outflow tract.N629D/N629D embryos manifest extensive apoptosis particularly in the first branchial arch and the facial region.Given that cells from the branchial arch populate the展开更多
文摘最近研究表明hERG(human ether-a—go-go related gene)基因编码的钾离子通道(hERG通道)作为一种广谱的药物靶标,被某些药物作用时会引起长QT间期综合征(LQTS),甚至导致具有生命危险的室性心律失常——尖端扭转性室性心动过速(TdP),引起制药公司和安全部门的广泛关注,现就hERG通道的结构和功能特征、不同亚基及细胞环境对其调节、目前临床前体内体外的研究方法及关于hERG通道的药物安全性评价进行简要介绍。
文摘The role of human ether a-go-go related gene(hERG) in electrically excitable cells has long been known.hERG currents IKr contribute to the re-polarisation phase 3 of the cardiac action potential. Mutations of this channel causes long QT syndrome. N629D hERG mutation(GFGN to GFGD) alters the pore selectivity signature sequence.N629D was over-expressed, via adenoviral gene transfer,in car-diomyocytes derived from mouse embryonic stem cells,the "IKr" showed outward rectification and an inward tail current,while WT IKr showed inward rectification and a positive tail current.N629D "IKr" phenotype also altered resting membrane potential and caused arrhythmia.Since hERG was reported to express in early stage of cardiogenesis,the role of the ERG potassium channel in cardiac development was elaborated in an in vivo model of a homozygous. The hERG N629D mutation was introduced into the orthologous mouse gene,mERG,by homologous recombination in mouse embryonic stem cells. N629D/N629D homozygous mutation results in embryonic lethality(died by E11.5).The mutation displayed defect cardiac morphogenesis including altered looping architecture,poorly developed bulbus cordis,and distorted aortic sac and branchial arches. N629D/N629D myocytes from embryonic day 9.5 embryos manifested complete loss of IKr function, depolarized resting potential,prolonged action potential duration(LQT),failure to repolarize,and propensity to oscillatory arrhythmias.Because deletion of transcription factor Hand2 produces apoptosis in similar regions and with a similar final developmental phenotype,Hand2 expression was evaluated. Robust decrease in Hand2 expression was observed in the secondary heart field in N629D/N629D embryos. mERG protein expression in the developing embryonic heart is not homogeneous.The protein expression is exaggerated in the right ventricle and in the outflow tract.N629D/N629D embryos manifest extensive apoptosis particularly in the first branchial arch and the facial region.Given that cells from the branchial arch populate the
