Smad, PI3K/Akt, and Wnt-Dependent Signaling Pathways Are Involved in BMP-4-Induced ESC Self-Renewal
Smad, PI3K/Akt, and Wnt-Dependent Signaling Pathways Are Involved in BMP-4-Induced ESC Self-Renewal
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DOI：
10.1002/stem.124
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发表时间：
2009-08-01
期刊：
影响因子：
5.2
通讯作者：
Han, Ho Jae
中科院分区：
文献类型：
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作者：
Lee, Min Young;Lim, Hyun Woo;Han, Ho Jae
已知骨形态发生蛋白4(BMP-4)对胚胎干细胞有多种作用。然而，其在小鼠胚胎干细胞中的确切作用机制尚不完全清楚。本研究旨在探讨BMP-4对ESC增殖及相关信号转导通路的影响。BMP-4显著增加[H-3]-胸腺嘧啶核苷掺入水平，并呈时间和剂量依赖关系。此外，BMP-4还以时间依赖的方式增加细胞周期蛋白D1的表达，降低p27(Kip1)的表达。BMP-4受体拮抗剂noggin可抑制BMP-4诱导的[H-3]-胸腺嘧啶核苷掺入和细胞周期蛋白D1表达的增加。BMP-4增加WNT1的表达。Smad4小干扰RNA(SiRNA)可抑制WNT1的表达，Smad4和Wnt1 siRNA可抑制BMP-4诱导的细胞周期蛋白D1的表达。BMP-4还激活β-连环素，而β-连环素被Smad4和Wnt1 siRNAs阻断。此外，BMP-4还可诱导Akt的磷酸化。磷脂酰肌醇3-激酶(PI3K)siRNA和Akt抑制剂可减弱BMP-4诱导的β-连环蛋白激活和细胞周期蛋白D1的表达。此外，siRNA下调Smad4、Wnt1和PI3K的表达降低了ESCs的多能性标志物mRNAs的水平，包括Oct4、Sox2和FoxD3。我们的结果表明，Smad4、Wnt1和PI3K基因敲除可显著减弱BMP-4诱导的[H-3]-胸腺嘧啶核苷掺入。综上所述，BMP-4通过Smad、PI3K/Akt和Wnt1/β-catenin参与维持小鼠胚胎干细胞的增殖和多能状态。干细胞2009；27：1858-1868
It is known that bone morphogenetic protein 4 (BMP-4) has a diverse effect on ESCs. However, its precise mechanism in mouse ESCs is not fully understood. We evaluated the effect of BMP-4 on ESC proliferation and its related signal cascades in this study. BMP-4 significantly increased the level of [H-3]-thymidine incorporation in time- (>= 8 hours) and dose-(>= 10 ng/ml) dependent manners. Additionally, BMP-4 increased cyclin D1 and decreased p27(kip1) expression values in a time-dependent manner. The increases in BMP-4-induced [H-3]-thymidine incorporation and cyclin D1 expression were inhibited by the BMP-4 receptor antagonist noggin. BMP-4 increased Wnt1 expression. Wnt1 expression was attenuated by Smad4 small interfering RNA (siRNA), and BMP-4-induced cyclin D1 expression was inhibited by Smad4 and Wnt1 siRNAs. BMP-4 also activated beta-catenin, which was blocked by Smad4 and Wnt1 siRNAs. In addition, BMP-4 induced Akt phosphorylation. BMP-4-induced beta-catenin activation and cyclin D1 expression were attenuated by phosphatidyl inositol 3-kinase (PI3K) siRNA and Akt inhibitor. Additionally, downregulation of Smad4, Wnt1, and PI3K expression by siRNA decreased the levels of pluripotency marker mRNAs of ESCs, including Oct4, Sox2, and FoxD3. Our results suggested that BMP-4-induced [H-3]-thymidine incorporation was significantly attenuated by Smad4, Wnt1, and PI3K knockdown. In conclusion, BMP-4 contributed to the maintenance of cell proliferation and the pluripotent state by Smad, PI3K/Akt, and Wnt1/beta-catenin in mouse ESCs. STEM CELLS 2009;27:1858-1868