钙/钙调蛋白依赖性蛋白激酶Ⅱ(Calcium/Calmodulin-dependent protein kinase Ⅱ,CaMKⅡ)是一种主要表达于心脏中的细胞信号分子,氧化激活的CaMKⅡ与多种致心律失常心脏疾病密切相关。为了分析氧化CaMKⅡ对于细胞电生理的影响,结合CaMK...钙/钙调蛋白依赖性蛋白激酶Ⅱ(Calcium/Calmodulin-dependent protein kinase Ⅱ,CaMKⅡ)是一种主要表达于心脏中的细胞信号分子,氧化激活的CaMKⅡ与多种致心律失常心脏疾病密切相关。为了分析氧化CaMKⅡ对于细胞电生理的影响,结合CaMKⅡ激活的生物化学动力学特征,开发了氧化CaMKⅡ人类心室细胞模型,模拟仿真研究活性氧(Reactive oxygen species,ROS)增强情况下,离子电流、细胞内钙循环和细胞膜动作电位的变化。仿真结果发现,当ROS的浓度升高时,CaMKⅡ的激活量增加,细胞质和肌浆网钙离子浓度升高,动作电位缩短。本模型为研究CaMKⅡ致心律失常提供了量化分析手段,构建了微观分子功能改变与宏观细胞动作电位变化之间的定量关系,具有重要的理论和应用价值。展开更多
目的急性缺血缺氧可致心功能受损和心律失常,钙离子在其中起重要作用,慢性缺氧对心功能及心肌细胞内钙离子活动同样产生影响,但机制不同。该研究拟通过慢性缺氧动物模型,研究慢性缺氧对心肌细胞内钙调素(calmodulin,CaM)、钙/钙调素依...目的急性缺血缺氧可致心功能受损和心律失常,钙离子在其中起重要作用,慢性缺氧对心功能及心肌细胞内钙离子活动同样产生影响,但机制不同。该研究拟通过慢性缺氧动物模型,研究慢性缺氧对心肌细胞内钙调素(calmodulin,CaM)、钙/钙调素依赖性蛋白激酶Ⅱ(calcium/calmodulin-dependent protein kinase Ⅱ,CaMKⅡ)的表达及其对细胞内Ca2+活动的影响,深入了解慢性缺氧对心脏功能及电活动的影响机制。方法通过吸入低浓度含氧气体(FiO2:10%)建立慢性缺氧大鼠动物模型。在实验1周和3周时,应用RT-PCR,Western Blot方法分别检测对照组和慢性缺氧组动物心肌细胞内CaM和CaMKⅡγ、CaMKIIδmRNA和蛋白表达;分离并培养正常心肌细胞和缺氧3周细胞,应用激光共聚焦法分别检测两种心肌细胞内Ca2+活动,同时应用CaMKⅡ特异性抑制剂KN-62,观察CaMKII在慢性缺氧下对心肌细胞内Ca2+活动的影响。结果实验1周和3周时,慢性缺氧大鼠心肌细胞内CaM和CaMKIIγ、CaMKIIδ的mRNA和蛋白表达均较正常动物高(P<0.01);在缺氧1周和3周组动物间CaM和CaMKIIδ也存在差异(P<0.01),但CaMKⅡγ无差异(P>0.05)。激光共聚焦研究发现,慢性缺氧心肌细胞内Ca2+活动其钙波振幅虽和正常心肌细胞无差异(P>0.05),但钙波时程延长(P<0.01);应用KN-62后,慢性缺氧动物钙波振幅和时程改变较明显(P<0.01)。结论慢性缺氧可使大鼠心肌细胞内CaM和CaMKⅡ合成代偿性增加,保持大鼠心肌细胞内钙稳态,从而在一定时期内维持心功能稳定。但随缺氧时间延长,心功能可受损并可致心律失常。展开更多
Objective:Cardiac hypertrophy is an adaptive reaction of the heart against cardiac overloading,but continuous cardiac hypertrophy can lead to cardiac remodeling and heart failure.Cardiac hypertrophy is mostly consider...Objective:Cardiac hypertrophy is an adaptive reaction of the heart against cardiac overloading,but continuous cardiac hypertrophy can lead to cardiac remodeling and heart failure.Cardiac hypertrophy is mostly considered reversible,and recent studies have indicated that decorin not only prevents cardiac fibrosis associated with hypertension,but also achieves therapeutic effects by blocking fibrosis-related signaling pathways.However,the mechanism of action of decorin remains unknown and unconfirmed.Methods:We determined the degree of myocardial hypertrophy by measuring the ratios of the heart weight/body weight and left ventricular weight/body weight,histological analysis and immunohistochemistry.Western blotting was performed to detect the expression levels of CaMKⅡ,p-CaMKⅡ and MEF-2 in the heart.Results:Our results confirmed that decorin can regulate the CaMKⅡ/MEF-2 signaling pathway,with inhibition thereof being similar to that of decorin in reducing cardiac hypertrophy.Conclusion:Taken together,the results of the present study showed that decorin induced cardiac hypertrophy by regulating the CaMKⅡ/MEF-2 signaling pathway in vivo,revealing a new therapeutic approach for the prevention of cardiac hypertrophy.展开更多
文摘目的急性缺血缺氧可致心功能受损和心律失常,钙离子在其中起重要作用,慢性缺氧对心功能及心肌细胞内钙离子活动同样产生影响,但机制不同。该研究拟通过慢性缺氧动物模型,研究慢性缺氧对心肌细胞内钙调素(calmodulin,CaM)、钙/钙调素依赖性蛋白激酶Ⅱ(calcium/calmodulin-dependent protein kinase Ⅱ,CaMKⅡ)的表达及其对细胞内Ca2+活动的影响,深入了解慢性缺氧对心脏功能及电活动的影响机制。方法通过吸入低浓度含氧气体(FiO2:10%)建立慢性缺氧大鼠动物模型。在实验1周和3周时,应用RT-PCR,Western Blot方法分别检测对照组和慢性缺氧组动物心肌细胞内CaM和CaMKⅡγ、CaMKIIδmRNA和蛋白表达;分离并培养正常心肌细胞和缺氧3周细胞,应用激光共聚焦法分别检测两种心肌细胞内Ca2+活动,同时应用CaMKⅡ特异性抑制剂KN-62,观察CaMKII在慢性缺氧下对心肌细胞内Ca2+活动的影响。结果实验1周和3周时,慢性缺氧大鼠心肌细胞内CaM和CaMKIIγ、CaMKIIδ的mRNA和蛋白表达均较正常动物高(P<0.01);在缺氧1周和3周组动物间CaM和CaMKIIδ也存在差异(P<0.01),但CaMKⅡγ无差异(P>0.05)。激光共聚焦研究发现,慢性缺氧心肌细胞内Ca2+活动其钙波振幅虽和正常心肌细胞无差异(P>0.05),但钙波时程延长(P<0.01);应用KN-62后,慢性缺氧动物钙波振幅和时程改变较明显(P<0.01)。结论慢性缺氧可使大鼠心肌细胞内CaM和CaMKⅡ合成代偿性增加,保持大鼠心肌细胞内钙稳态,从而在一定时期内维持心功能稳定。但随缺氧时间延长,心功能可受损并可致心律失常。
文摘Objective:Cardiac hypertrophy is an adaptive reaction of the heart against cardiac overloading,but continuous cardiac hypertrophy can lead to cardiac remodeling and heart failure.Cardiac hypertrophy is mostly considered reversible,and recent studies have indicated that decorin not only prevents cardiac fibrosis associated with hypertension,but also achieves therapeutic effects by blocking fibrosis-related signaling pathways.However,the mechanism of action of decorin remains unknown and unconfirmed.Methods:We determined the degree of myocardial hypertrophy by measuring the ratios of the heart weight/body weight and left ventricular weight/body weight,histological analysis and immunohistochemistry.Western blotting was performed to detect the expression levels of CaMKⅡ,p-CaMKⅡ and MEF-2 in the heart.Results:Our results confirmed that decorin can regulate the CaMKⅡ/MEF-2 signaling pathway,with inhibition thereof being similar to that of decorin in reducing cardiac hypertrophy.Conclusion:Taken together,the results of the present study showed that decorin induced cardiac hypertrophy by regulating the CaMKⅡ/MEF-2 signaling pathway in vivo,revealing a new therapeutic approach for the prevention of cardiac hypertrophy.
