Fluid shear stress induces differentiation of Flk-1-positive embryonic stem cells into vascular endothelial cells in vitro
Fluid shear stress induces differentiation of Flk-1-positive embryonic stem cells into vascular endothelial cells in vitro
复制标题
DOI：
10.1152/ajpheart.00956.2004
复制
发表时间：
2005-04-01
影响因子：
4.8
通讯作者：
Ando, J
中科院分区：
文献类型：
--
作者：
Yamamoto, K;Sokabe, T;Ando, J
多能胚胎干细胞（ES）能够分化为所有细胞系，但调控ES细胞分化的分子机制尚未得到充分探索。在这项研究中，我们报道了剪切应力，一种由流体流动产生的机械力，可以诱导胚胎干细胞分化。当Flk-1阳性（Flk-1(+)）小鼠ES细胞受到剪切胁迫时，其细胞密度明显增加，细胞周期S期和G(2)-M期的细胞比例高于静态培养的Flk-1(+) ES细胞。剪切应力在蛋白水平和mRNA水平上显著增加了血管内皮细胞特异性标志物Flk-1、Flt-1、血管内皮钙粘蛋白和PECAM-1的表达，但对壁细胞标志物平滑肌α -肌动蛋白、血细胞标志物CD3和上皮细胞标志物角蛋白的表达没有影响。这些发现表明，剪切应力选择性地促进Flk-1(+) ES细胞向内皮细胞谱系分化。剪切应力下的Flk-1(+) ES细胞在胶原凝胶中形成管状结构，并形成广泛的管状网络，明显快于静态对照。剪切应力诱导Flk-1(+) ES细胞中Flk-1的酪氨酸磷酸化，该磷酸化被Flk-1激酶抑制剂SU1498阻断，但不被抗VEGF的中和抗体阻断。SU1498还能消除剪切应力诱导的Flk-1(+) ES细胞的增殖和分化，表明Flk-1的非配体激活在剪切应力介导的Flk-1(+) ES细胞的增殖和分化中起重要作用。
Pluripotent embryonic stem (ES) cells are capable of differentiating into all cell lineages, but the molecular mechanisms that regulate ES cell differentiation have not been sufficiently explored. In this study, we report that shear stress, a mechanical force generated by fluid flow, can induce ES cell differentiation. When Flk-1-positive (Flk-1(+)) mouse ES cells were subjected to shear stress, their cell density increased markedly, and a larger percentage of the cells were in the S and G(2)-M phases of the cell cycle than Flk-1(+) ES cells cultured under static conditions. Shear stress significantly increased the expression of the vascular endothelial cell-specific markers Flk-1, Flt-1, vascular endothelial cadherin, and PECAM-1 at both the protein level and the mRNA level, but it had no effect on expression of the mural cell marker smooth muscle alpha-actin, blood cell marker CD3, or the epithelial cell marker keratin. These findings indicate that shear stress selectively promotes the differentiation of Flk-1(+) ES cells into the endothelial cell lineage. The shear stressed Flk-1(+) ES cells formed tubelike structures in collagen gel and developed an extensive tubular network significantly faster than the static controls. Shear stress induced tyrosine phosphorylation of Flk-1 in Flk-1(+) ES cells that was blocked by a Flk-1 kinase inhibitor, SU1498, but not by a neutralizing antibody against VEGF. SU1498 also abolished the shear stress-induced proliferation and differentiation of Flk-1(+) ES cells, indicating that a ligand-independent activation of Flk-1 plays an important role in the shear stress-mediated proliferation and differentiation by Flk-1(+) ES cells.