Integrins regulate mouse embryonic stem cell self-renewal
Integrins regulate mouse embryonic stem cell self-renewal
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DOI：
10.1634/stemcells.2007-0103
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发表时间：
2007-01-01
期刊：
影响因子：
5.2
通讯作者：
Asashima, Makoto
中科院分区：
文献类型：
--
作者：
Hayashi, Yohei;Furue, Miho Kusuda;Asashima, Makoto
细胞外基质（ECM）成分调节干细胞的行为，但在胚胎干细胞（ES）中引起的确切影响知之甚少。我们以前开发了一种简单的，确定的，无血清培养基，含有白血病抑制因子（LIF）的繁殖多能小鼠胚胎干细胞（mES）在饲养细胞的情况下。在这项研究中，我们确定了ECM成分作为培养基质的mES细胞自我更新的影响，在此培养基中，比较传统的培养条件下，含有血清和LIF与明胶作为培养基质。当在I型和IV型胶原或聚-D-赖氨酸上培养时，mES细胞保持未分化。然而，他们分化时，培养层粘连蛋白或纤连蛋白的改变形态所示，碱性磷酸酶的活性下降，Fgf 5表达增加，Nanog和阶段特异性胚胎抗原1的表达下降。在此条件下，维持细胞自我更新的信号转导和转录激活因子（STAT）3和Akt/蛋白激酶B（PKB）的活性降低。相反，细胞外信号调节激酶（ERK）1/2活性，负控制细胞自我更新，增加。在规定的条件下，mES细胞不表达胶原结合整合素亚基，但它们表达层粘连蛋白和纤连蛋白结合整合素亚基。一些胶原结合整合素亚单位的表达下调，在LIF浓度依赖性的方式。阻断ECM和整合素之间的相互作用可抑制这种分化。相反，ECM整合素相互作用的刺激过度表达胶原结合整合素亚基诱导分化的mES细胞培养在I型胶原。研究结果表明，整合素信号转导的失活在促进小鼠胚胎干细胞自我更新中至关重要。
Extracellular matrix (ECM) components regulate stem-cell behavior, although the exact effects elicited in embryonic stem (ES) cells are poorly understood. We previously developed a simple, defined, serum-free culture medium that contains leukemia inhibitory factor (LIF) for propagating pluripotent mouse embryonic stem (mES) cells in the absence of feeder cells. In this study, we determined the effects of ECM components as culture substrata on mES cell self-renewal in this culture medium, comparing conventional culture conditions that contain serum and LIF with gelatin as a culture substratum. mES cells remained undifferentiated when cultured on type I and type IV collagen or poly-D-lysine. However, they differentiated when cultured on laminin or fibronectin as indicated by altered morphologies, the activity of alkaline phosphatase decreased, Fgf5 expression increased, and Nanog and stage-specific embryonic antigen 1 expression decreased. Under these conditions, the activity of signal transducer and activator of transcription ( STAT) 3 and Akt/protein kinase B (PKB), which maintain cell self-renewal, decreased. In contrast, the extracellular signal-regulated kinase (ERK) 1/2 activity, which negatively controls cell self-renewal, increased. In the defined conditions, mES cells did not express collagen-binding integrin subunits, but they expressed laminin- and fibronectin-binding integrin subunits. The expression of some collagen-binding integrin subunits was downregulated in an LIF concentration-dependent manner. Blocking the interactions between ECM and integrins inhibited this differentiation. Conversely, the stimulation of ECM-integrin interactions by overexpressing collagen-binding integrin subunits induced differentiation of mES cells cultured on type I collagen. The results of the study indicated that inactivation of the integrin signaling is crucial in promoting mouse embryonic stem cell self-renewal.