Functional properties of human embryonic stem cell-derived cardiomyocytes:: Intracellular Ca2+ handling and the role of sarcoplasmic reticulum in the contraction
Functional properties of human embryonic stem cell-derived cardiomyocytes:: Intracellular Ca2+ handling and the role of sarcoplasmic reticulum in the contraction
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DOI：
10.1634/stemcells.2005-0036
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发表时间：
2006-02-01
期刊：
影响因子：
5.2
通讯作者：
Binah, Ofer
中科院分区：
文献类型：
--
作者：
Dolnikov, Katya;Shilkrut, Mark;Binah, Ofer
由于心脏移植受到供体器官数量少的限制，通过细胞移植使患病心肌再生是一种有吸引力的治疗方式。为了确定人胚胎干细胞衍生的心肌细胞（hESC-CMs）（7至55天）与心肌的相容性，我们研究了它们在细胞内Ca 2+处理和肌浆网在收缩中的作用方面的功能特性。通过同时记录[Ca 2 +]（i）瞬变和收缩来研究hESC-CM的功能特性。此外，我们进行了蛋白质印迹分析的钙处理蛋白SERCA 2，钙螯合蛋白，受磷蛋白，和Na+/Ca 2+交换（NCX）。我们的主要发现是，首先，hESCCM显示时间相关的[Ca 2 +]（i）瞬变和收缩，负力-频率关系，缺乏休息后增强。第二，ryanodine，毒胡萝卜素，咖啡因不影响[Ca 2 +]（i）瞬变和收缩，表明在这个发育阶段，收缩依赖于跨肌膜Ca 2+内流，而不是肌浆网Ca 2+释放。第三，与电压依赖性Ca 2+电流存在于hESC-CM中并有助于机械功能的观点一致，维拉帕米完全阻断收缩。第四，尽管hESC-CM表达SERCA 2和NCX的水平与成年猪心肌相当，但不表达钙螯合蛋白和受磷蛋白。我们的研究首次表明，与hESC-CM的细胞内Ca 2+处理相关的功能特性与成人心肌显著不同，可能是由于不成熟的肌浆网能力。
Since cardiac transplantation is limited by the small availability of donor organs, regeneration of the diseased myocardium by cell transplantation is an attractive therapeutic modality. To determine the compatibility of human embryonic stem cell-derived cardiomyocytes (hESC-CMs) (7 to 55 days old) with the myocardium, we investigated their functional properties regarding intracellular Ca2+ handling and the role of the sarcoplasmic reticulum in the contraction. The functional properties of hESC-CMs were investigated by recording simultaneously [Ca2+](i) transients and contractions. Additionally, we performed Western blot analysis of the Ca2+-handling proteins SERCA2, calsequestrin, phospholamban, and Na+/Ca2+ exchanger (NCX). Our major findings are, first, that hESCCMs displayed temporally related [Ca2+](i) transients and contractions, negative force-frequency relations, and lack of post-rest potentiation. Second, ryanodine, thapsigargin, and caffeine did not affect the [Ca2+](i) transient and contraction, indicating that at this developmental stage, contraction depends on transsarcolemmal Ca2+ influx rather than on sarcoplasmic reticulum Ca2+ release. Third, in agreement with the notion that a voltage-dependent Ca2+ current is present in hESC-CMs and contributes to the mechanical function, verapamil completely blocked contraction. Fourth, whereas hESC-CMs expressed SERCA2 and NCX at levels comparable to those of the adult porcine myocardium, calsequestrin and phospholamban were not expressed. Our study shows for the first time that functional properties related to intracellular Ca2+ handling of hESC-CMs differ markedly from the adult myocardium, probably due to immature sarcoplasmic reticulum capacity.