Schmelter Maike, Ateghang Bernadette, Helmig Simone, Wartenberg Maria, Sauer Heinrich
Department of Physiology Justus-Liebig-University Giessen, Aulweg 129 Giessen 35392, Germany.
FASEB J. 2006 Jun;20(8):1182-4. doi: 10.1096/fj.05-4723fje. Epub 2006 Apr 24.
Growing stem cells are subjected to mechanical forces, which may initiate differentiation programs. Mechanical strain stimulated cardiovascular differentiation of mouse embryonic stem (ES) cells as evaluated by quantification of contracting cardiac foci and capillary areas, respectively. Mechanical strain rapidly elevated intracellular reactive oxygen species (ROS). After 24 h up-regulation of NADPH oxidase subunits p22-phox, p47-phox, p67-phox, and Nox-4 as well as Nox-1 and Nox-4 mRNA was observed. In parallel, mechanical strain increased hypoxia-inducible factor-1alpha (HIF-1alpha) and vascular endothelial growth factor (VEGF) mRNA and protein as well as MEF2C and GATA-4 mRNA, which are involved in cardiovascular development. Furthermore, phosphorylation of extracellular-regulated kinase 1,2 (ERK1,2), p38, and c-jun N-terminal kinase (c-Jun NH2-terminal kinase (JNK)) was observed. Stimulation of cardiovascular commitment, HIF-1alpha, VEGF, and MEF2C expression as well as MAPK activation were abolished by free radical scavengers, whereas GATA-4 expression was increased. Cardiomyogenesis was inhibited by the p38 inhibitor SB203580, the ERK1,2 inhibitor UO126, and the JNK inhibitor SP600125. Vasculogenesis/angiogenesis was blunted following inhibition of ERK1,2 and JNK, whereas p38 inhibition was ineffective. Our data outline a role of ROS as mechanotransducing molecules in mechanical strain-stimulated cardiovascular differentiation of ES cells, and point toward a microenvironment of elevated ROS required for signaling cascades initiating cardiovascular differentiation programs.
正在生长的干细胞会受到机械力作用，这可能启动分化程序。通过分别对收缩性心脏灶和毛细血管区域进行定量评估发现，机械应变刺激了小鼠胚胎干细胞（ES细胞）的心血管分化。机械应变迅速升高细胞内活性氧（ROS）水平。24小时后，观察到NADPH氧化酶亚基p22 - phox、p47 - phox、p67 - phox和Nox - 4以及Nox - 1和Nox - 4 mRNA上调。同时，机械应变增加了参与心血管发育的缺氧诱导因子 - 1α（HIF - 1α）和血管内皮生长因子（VEGF）的mRNA及蛋白水平，以及MEF2C和GATA - 4 mRNA水平。此外，还观察到细胞外调节激酶1,2（ERK1,2）、p38和c - jun N端激酶（c - Jun NH2末端激酶（JNK））的磷酸化。自由基清除剂消除了心血管定向分化、HIF - 1α、VEGF和MEF2C表达以及MAPK激活，而GATA - 4表达增加。p38抑制剂SB203580、ERK1,2抑制剂UO126和JNK抑制剂SP600125抑制了心肌生成。抑制ERK1,2和JNK后血管生成/血管发生减弱，而抑制p38则无效。我们的数据概述了ROS作为机械转导分子在机械应变刺激的ES细胞心血管分化中的作用，并指出启动心血管分化程序的信号级联反应需要升高的ROS微环境。
