Wei Rui, Yang Jin, Gao Meijuan, Wang Haining, Hou Wenfang, Mu Yiming, Chen Guian, Hong Tianpei
Department of Endocrinology and Metabolism, Peking University Third Hospital, No. 49 North Garden Road, Haidian District, Beijing, 100191, China.
Clinical Stem Cell Research Centre, Peking University Third Hospital, Beijing, China.
Cell Biol Int. 2016 Nov;40(11):1235-1246. doi: 10.1002/cbin.10679. Epub 2016 Sep 15.
Microenvironment regulates cell fate and function. In this study, we investigated the effects of the infarcted cardiac microenvironment on cardiac differentiation of human embryonic stem cells (hESCs). hESCs were intramyocardially transplanted into infarcted or uninjured rat hearts. After 4 weeks, mesodermal and cardiac lineage markers were detected by immunofluorescence. Cardiac function was assessed by echocardiography. hESCs were differentiated in vitro under hypoxic (5% O ), low-nutrient (5% FBS), or control condition. The numbers of beating clusters, proportions of cardiac troponin T (cTnT)-positive cells, and relative levels of cardiac-specific markers were determined. Results showed that in both uninjured and infarcted hearts, hESCs survived, underwent development, and formed intracardiac grafts, with a higher proportion in the uninjured hearts. However, cells that were double positive for human fetal liver kinase 1 (Flk1), a marker of cardiac progenitors, and human β-tubulin, a marker for labeling human cells, were found in the uninjured hearts but not in the infarcted hearts. hESC transplantation did not restore the cardiac function of acutely infarcted rats. In vitro, low FBS treatment was associated with fewer beating clusters, a lower proportion of cTnT-positive cells and lower levels of cardiac troponin I (cTnI) and α-myosin heavy chain (α-MHC) expression than those in the control. Conversely, hypoxia treatment was associated with a higher proportion of cTnT-positive cells and higher levels of cTnI expression. In conclusion, transplanted hESCs differentiate toward Flk1-positive cardiac progenitors in the uninjured but not infarcted hearts. The infarcted cardiac microenvironment recapitulated is unsuitable for cardiac differentiation of hESCs, likely due to nutrient deprivation.
微环境调节细胞命运和功能。在本研究中，我们调查了梗死心脏微环境对人胚胎干细胞（hESCs）心脏分化的影响。将hESCs心肌内移植到梗死或未损伤的大鼠心脏中。4周后，通过免疫荧光检测中胚层和心脏谱系标志物。通过超声心动图评估心脏功能。将hESCs在低氧（5% O₂）、低营养（5%胎牛血清）或对照条件下进行体外分化。测定跳动细胞团的数量、心肌肌钙蛋白T（cTnT）阳性细胞的比例以及心脏特异性标志物的相对水平。结果显示，在未损伤和梗死的心脏中，hESCs均存活、发育并形成心内移植物，在未损伤心脏中的比例更高。然而，在未损伤心脏中发现了心脏祖细胞标志物人胎儿肝激酶1（Flk1）和标记人细胞的标志物人β-微管蛋白双阳性的细胞，而在梗死心脏中未发现。hESC移植未能恢复急性梗死大鼠的心脏功能。在体外，与对照相比，低胎牛血清处理导致跳动细胞团数量减少、cTnT阳性细胞比例降低以及心肌肌钙蛋白I（cTnI）和α-肌球蛋白重链（α-MHC）表达水平降低。相反，低氧处理导致cTnT阳性细胞比例更高以及cTnI表达水平更高。总之，移植的hESCs在未损伤而非梗死的心脏中向Flk1阳性心脏祖细胞分化。模拟的梗死心脏微环境不适用于hESCs的心脏分化，可能是由于营养缺乏。
