Department of Physiology and Biophysics, University of Illinois at Chicago, Chicago, IL 60612, USA.
J Mol Cell Cardiol. 2012 Sep;53(3):382-91. doi: 10.1016/j.yjmcc.2012.06.003. Epub 2012 Jun 16.
Our aim was to further elucidate the cardiac lineage development of bone marrow-derived mesenchymal stem cells (MSC) and to identify cells which had the potential for cardiac myogenic differentiation when compared to skeletal muscle satellite (Sk-sat) myogenesis. Unlike Sk-sat, MSC expressed the early cardiac markers Nkx2.5 and GATA4. Their expression was significantly increased by culturing MSC with Bone Morphogenetic Protein 4 (BMP4). Enhanced cardiac myogenic lineage differentiation and loss of stem cell characteristics induced by BMP4 were further confirmed by flow cytometry of cells stained for Nkx2.5 and Sca-1 expression. MSC also expressed skeletal genes (MyoG, ssTnI, Sk-Act) early in culture but their expression was suppressed when BMP4 was added from day 0 to day 6 (p<0.05). BMP4 treated MSC also exhibited a 6-fold increase in cTnI expression by day 12 in culture. The average MSC action potential time duration at 90% (APD90) was 32.3±4ms, with some cells exhibiting action potentials closer to Sk-sat APD90 of 13.7±0.9ms. After treatment with BMP4, MSC significantly increased their APD90 to 54.4±7.6ms, shifting from the shorter skeletal-like signature, towards a longer action potential duration more characteristic of a cardiomyocyte signature. Our results show that MSC and Sk-sat exhibit similarities in myogenic lineage development early in culture but that BMP4 clearly enhances cardiac myogenic development, suppresses skeletal myogenesis, and leads to loss of "stemness" in MSC. These findings provide novel information regarding the use of BMP4 to accelerate cardiac myogenic development in harvested MSC and further support the use of MSC in cardiac regenerative therapy.
我们的目的是进一步阐明骨髓间充质干细胞（MSC）的心脏谱系发育，并确定与骨骼肌卫星（Sk-sat）肌发生相比具有心脏肌生成潜能的细胞。与 Sk-sat 不同，MSC 表达早期心脏标志物 Nkx2.5 和 GATA4。通过用骨形态发生蛋白 4（BMP4）培养 MSC，其表达显著增加。通过对表达 Nkx2.5 和 Sca-1 的细胞进行流式细胞术进一步证实了 BMP4 增强的心脏肌生成谱系分化和干细胞特性的丧失。MSC 也在培养的早期表达骨骼基因（MyoG、ssTnI、Sk-Act），但当从第 0 天到第 6 天添加 BMP4 时，其表达受到抑制（p<0.05）。BMP4 处理的 MSC 在培养第 12 天也表现出 cTnI 表达增加 6 倍。90%（APD90）时平均 MSC 动作电位时程为 32.3±4ms，一些细胞的动作电位更接近 Sk-sat 的 APD90（13.7±0.9ms）。用 BMP4 处理后，MSC 的 APD90 显著增加到 54.4±7.6ms，从更短的类似于骨骼的特征转变为更具心肌细胞特征的更长的动作电位时程。我们的结果表明，MSC 和 Sk-sat 在培养的早期在肌生成谱系发育方面表现出相似性，但 BMP4 显然增强了心脏肌生成发育，抑制了骨骼肌生成，并导致 MSC 失去“干性”。这些发现为使用 BMP4 加速收获的 MSC 中的心脏肌生成发育提供了新的信息，并进一步支持将 MSC 用于心脏再生治疗。
