GATA-6 promotes cell survival by up-regulating BMP-2 expression during embryonic stem cell differentiation.
GATA-6 promotes cell survival by up-regulating BMP-2 expression during embryonic stem cell differentiation.
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DOI：
10.1091/mbc.e12-04-0313
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发表时间：
2012-09
影响因子：
3.3
通讯作者：
Li S
中科院分区：
文献类型：
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作者：
Rong L;Liu J;Qi Y;Graham AM;Parmacek MS;Li S
转录因子GATA-6在类胚体中的遗传失活在ES细胞分化的早期阶段诱导大量的细胞凋亡。有证据表明，BMP-2是GATA-6的直接转录靶点，并与内胚层来源的基底膜协同介导GATA-6依赖的细胞存活。GATA-6是一种锌指转录因子，对早期胚胎发育至关重要。去除小鼠GATA-6会损害内胚层分化并导致上皮细胞凋亡。内胚层缺陷被归因于HNF4、DISABLED-2和GATA-4的缺失。然而，表皮细胞凋亡的机制尚不清楚。在本研究中，我们以小鼠胚胎干细胞衍生的类胚体(EBS)作为围着床期发育的模型，发现去除GATA-6会在EB分化过程中引起大量的细胞凋亡。内胚层移植实验和异位基底膜(BM)组装表明，BM和非BM因子都有助于细胞存活。此外，突变型EBS的细胞死亡增加伴随着骨形态发生蛋白2(BMP-2)的表达减少。染色质免疫沉淀显示GATA-6与BMP2启动子直接结合。用BMP-2处理突变型EBS可显著抑制细胞凋亡，而BMP拮抗剂noggin或显性负性BMP受体在正常EBS中的稳定过表达则导致细胞凋亡增加。最后，在没有GATA-6的情况下，Smad1/5的磷酸化激活被显著抑制，而这一作用可被外源性BMP-2逆转。用SMAD磷酸化抑制剂处理正常EBS可增加细胞凋亡。综上所述，这些结果表明GATA-6通过调节胚胎上皮形态发生过程中内胚层BMP-2和BM的表达来促进细胞存活。
Genetic inactivation of the transcription factor GATA-6 in the embryoid body induces massive apoptosis at the early stage of ES cell differentiation. Evidence is provided that BMP-2 is a direct transcription target of GATA-6 and mediates GATA-6-dependent cell survival in concert with endoderm-derived basement membrane. GATA-6 is a zinc-finger transcription factor essential for early embryogenesis. Ablation of GATA-6 in mice impairs endoderm differentiation and causes apoptosis of epiblast cells. The endoderm defects have been attributed to the loss of HNF4, disabled-2, and GATA-4. However, the mechanisms underlying epiblast apoptosis are unclear. In this study we used mouse embryonic stem cell–derived embryoid bodies (EBs) as a model for peri-implantation development and found that ablation of GATA-6 causes massive apoptosis during EB differentiation. Endoderm grafting experiments and ectopic basement membrane (BM) assembly suggest that both BM and non-BM factors contribute to cell survival. Furthermore, the increased cell death in mutant EBs is accompanied by reduced expression of bone morphogenetic protein 2 (BMP-2). Chromatin immunoprecipitation reveals direct binding of GATA-6 to the Bmp2 promoter. Treatment of the mutant EBs with BMP-2 markedly suppresses apoptosis, whereas stable overexpression of the BMP antagonist noggin or a dominant-negative BMP receptor in normal EBs leads to increased apoptosis. Last, activation of SMAD1/5 by phosphorylation is significantly inhibited in the absence of GATA-6, and this is reversed by exogenous BMP-2. Treatment of normal EBs with SMAD phosphorylation inhibitor increases apoptosis. Collectively these results suggest that GATA-6 promotes cell survival by regulating endoderm expression of BMP-2 and BM during embryonic epithelial morphogenesis.