Guan Kaomei, Wagner Stefan, Unsöld Bernhard, Maier Lars S, Kaiser Diana, Hemmerlein Bernhard, Nayernia Karim, Engel Wolfgang, Hasenfuss Gerd
Department of Cardiology and Pneumology, Georg-August-University of Göttingen, Göttingen, Germany.
Circ Res. 2007 Jun 8;100(11):1615-25. doi: 10.1161/01.RES.0000269182.22798.d9. Epub 2007 May 3.
Stem cell-based therapy is a promising approach for the treatment of heart failure. Adult stem cells with the pluripotency of embryonic stem cells (ESCs) would be an ideal cell source. Recently, we reported the successful establishment of multipotent adult germline stem cells (maGSCs) from mouse testis. These cultured maGSCs show phenotypic characteristics similar to ESCs and can spontaneously differentiate into cells from all 3 germ layers. In the present study, we used the hanging drop method to differentiate maGSCs into cardiomyocytes and analyzed their functional properties. Differentiation efficiency of beating cardiomyocytes from maGSCs was similar to that from ESCs. The maGSC-derived cardiomyocytes expressed cardiac-specific L-type Ca(2+) channels and responded to Ca(2+) channel-modulating drugs. Cx43 was expressed at cell-to-cell contacts in cardiac clusters, and fluorescence recovery after photobleaching assay showed the presence of functional gap junctions among cardiomyocytes. Action potential analyses demonstrated the presence of pacemaker-, ventricle-, atrial-, and Purkinje-like cardiomyocytes. Stimulation with isoproterenol resulted in a significant increase in beating frequency, whereas the addition of cadmium chloride abolished spontaneous electrical activity. Confocal microscopy analysis of intracellular Ca(2+) in maGSC-derived cardiomyocytes showed that calcium increased periodically throughout the cell in a homogenous fashion, pointing to a fine regulated Ca(2+) release from intracellular Ca(2+) stores. By using line-scan mode, we found rhythmic Ca(2+) transients. Furthermore, we transplanted maGSCs into normal hearts of mice and found that maGSCs were able to proliferate and differentiate. No tumor formation was found up to 1 month after cell transplantation. Taken together, we believe that maGSCs provide a new source of distinct types of cardiomyocytes for basic research and potential therapeutic application.
基于干细胞的疗法是治疗心力衰竭的一种有前景的方法。具有胚胎干细胞（ESC）多能性的成体干细胞将是理想的细胞来源。最近，我们报道了从小鼠睾丸成功建立多能成体生殖系干细胞（maGSC）。这些培养的maGSC表现出与ESC相似的表型特征，并且可以自发分化为所有三个胚层的细胞。在本研究中，我们使用悬滴法将maGSC分化为心肌细胞并分析其功能特性。maGSC分化为跳动心肌细胞的效率与ESC相似。maGSC来源的心肌细胞表达心脏特异性L型Ca（2+）通道，并对Ca（2+）通道调节药物有反应。Cx43在心脏细胞簇的细胞间接触处表达，光漂白后荧光恢复分析表明心肌细胞之间存在功能性缝隙连接。动作电位分析证明存在起搏样、心室样、心房样和浦肯野样心肌细胞。异丙肾上腺素刺激导致跳动频率显著增加，而添加氯化镉则消除了自发电活动。对maGSC来源的心肌细胞内Ca（2+）的共聚焦显微镜分析表明，钙以均匀的方式在整个细胞中周期性增加，表明从细胞内Ca（2+）储存中精细调节Ca（2+）释放。通过使用线扫描模式，我们发现了有节奏的Ca（2+）瞬变。此外，我们将maGSC移植到小鼠的正常心脏中，发现maGSC能够增殖和分化。细胞移植后1个月内未发现肿瘤形成。综上所述，我们认为maGSC为基础研究和潜在的治疗应用提供了一种新的不同类型心肌细胞的来源。
