TEAD4 and Trophoblast Lineage

描述（由申请方提供）：滋养层细胞谱系构建器官胎盘的功能单位，对于胚胎与母体的锚定、建立营养和气体运输至胚胎的血管连接以及表达妊娠成功进展所需的激素非常重要。滋养层细胞谱系的发育缺陷导致胚胎植入失败或妊娠相关疾病如先兆子痫。因此，重要的是要了解调节滋养层细胞谱系发育的分子途径。滋养层细胞谱系的起源始于滋养外胚层（TE）的建立，滋养外胚层是滋养层细胞的第一个分化阶段之一。 两种细胞谱系在植入前哺乳动物发育过程中被指定。在小鼠中的基因敲除研究表明，TEAD 4，一个成员的TEA结构域含有转录因子，是主协调员的TE特异性转录程序。无TEAD 4的胚胎不能成熟到胚泡阶段，并且缺乏滋养层发育的主要调节因子如CDX 2和GATA 3的表达。有趣的是，尽管TEAD 4在小鼠发育早期特异性调节TE/滋养层特异性基因表达，但在TE或发育胎盘的滋养层祖细胞中尚未鉴定出TEAD 4的直接靶点。此外，尚未测试TEAD 4在胚胎植入后滋养层谱系发育期间的功能重要性。因此，TEAD 4调节滋养层细胞谱系发育的分子机制知之甚少。该提案的目标是确定TEAD 4选择性地协调滋养层干细胞特异性转录程序的分子机制。提出了两个具体的目标;在目标1中，我们将定义滋养层细胞中的全球TEAD 4依赖性转录网络。使用小鼠和大鼠作为模型系统，我们将测试的假设，TEAD 4调节一个核心TSC特异性转录网络内的TE植入前胚胎。我们将使用染色质免疫沉淀沿着全基因组测序（ChIP-Seq）来鉴定滋养层细胞中的TEAD 4靶基因，并定义一个全球TEAD 4依赖性滋养层特异性转录网络。 在目标2中，我们将确定TEAD 4在着床后滋养细胞谱系发育中的重要性。我们将检验这一假设，即与植入前TE谱系发育相似，TEAD 4功能对于维持发育中胎盘的滋养层祖细胞内TSC特异性基因的表达也很重要，胚胎植入后TEAD 4功能受损将对滋养层谱系的发育产生负面影响。

DESCRIPTION (provided by applicant): Trophoblast cell lineages build the functional units of the organ, the placenta and are important for the anchorage of the embryo to the mother, for establishing a vascular connection for nutrient and gas transport to the embryo, and expression of hormones that are required for the successful progression of pregnancy. Defective development of the trophoblast cell lineages leads to either failure of embryo implantation or pregnancy associated disorders like preeclampsia. Thus it is important to understand molecular pathways that regulate development of the trophoblast cell lineages. The origination of trophoblast cell lineages starts with the establishment of the trophectoderm (TE), one of the first two cell lineages that are specified during preimplantation mammalian development. Gene knockout studies in mice showed that TEAD4, a member of TEA-domain containing transcription factors, is the master orchestrator of the TE-specific transcriptional program. TEAD4-null embryos do not mature to the blastocyst stage and lack expression of master regulators of trophoblast development, like CDX2, and GATA3. Interestingly, although TEAD4 specifically regulates TE/trophoblast-specific gene expression during early mouse development, direct targets of TEAD4 have not been identified in the TE or in trophoblast progenitors of the developing placenta. Furthermore, functional importance of TEAD4 during trophoblast lineage development after embryo implantation has not been tested. Thus, the molecular mechanisms by which TEAD4 regulates trophoblast lineage development are poorly understood. The goal of this proposal is to define molecular mechanisms by which TEAD4 selectively orchestrate a trophoblast stem cell-specific transcriptional program. Two specific aims are proposed; in aim 1, we will define global TEAD4-dependent transcriptional network in trophoblast cells. Using both mouse and rat as model systems, we will test the hypothesis that TEAD4 regulates a core TSC-specific transcriptional network within the TE of a preimplantation embryo. We will use chromatin immunoprecipitation along with genome wide sequencing (ChIP-Seq) to identify TEAD4 target genes in trophoblast cells and to define a global TEAD4-dependent, trophoblast-specific transcriptional network. In aim 2, we will determine importance of TEAD4 in postimplantation trophoblast lineage development. We will test the hypothesis that similar to preimplantation TE-lineage development, TEAD4 function is also important to maintain expression of TSC-specific genes within the trophoblast progenitors of the developing placenta and impairment of TEAD4 function after embryo implantation will negatively affect development of trophoblast lineages.