Regulation of embryonic epithelial morphogenesis

胚胎上皮形态发生的调节

基本信息

批准号：
7898061
负责人：
Shaohua Li
金额：
$ 10.86万
依托单位：
UNIV OF MED/DENT NJ-R W JOHNSON MED SCH
依托单位国家：
美国
项目类别：
财政年份：
2009
资助国家：
美国
起止时间：
2009-09-01 至 2010-08-31
项目状态：
已结题

来源：
https://reporter.nih.gov/project-details/7898061
关键词：
1-Phosphatidylinositol 3-Kinase Adhesions Affect Apical Apoptosis Architecture Basement membrane Binding Biochemical Genetics Biological Models Biology Cancer Biology Cell Polarity Cell Survival Cell membrane Cells Complex Cues DNA DOCK1 protein Data Defect Development Dominant-Negative Mutation Embryo Embryonic Development Environment Epiblast Epithelial Epithelial cyst Epithelium Event Exhibits Exocytosis Experimental Models Figs - dietary GTP Binding Genes Goals Guanine Nucleotide Exchange Factors IQ motif containing GTPase activating protein 1 In Situ Nick-End Labeling In Vitro Inner Cell Mass Integrins Lead Maintenance Malignant - descriptor Mediating Methods Microtubules Molecular Morphogenesis Mus Natural regeneration Pathway interactions Phenotype Play Process Proteins Recruitment Activity Regulation Retroviridae Role Signal Transduction Staging Staining method Stains Testing Time Tissue Engineering Tissues Undifferentiated Work Wound Healing blastocyst caspase-3 embryonic stem cell extracellular genetic manipulation implantation integrin-linked kinase knock-down mutant natural Blastocyst Implantation novel protein complex protein transport rho GTP-Binding Proteins small hairpin RNA tissue regeneration tool trafficking

项目摘要

Formation of polarized epithelium is fundamental to embryonic development. During mouse peri- implantation development, the undifferentiated inner cell mass of the blastocyst is converted from a nonpolar cell aggregate to a highly organized epithelial cyst. This morphogenetic transformation involves the polarization and basement membrane (BM)-dependent survival of epiblast epithelium. However, the molecular mechanisms underlying these processes are largely unknown. The mouse peri-implantation development can be recapitulated by in vitro cultured embryoid bodies (EBs) differentiated from embryonic stem cells. Using genetically modified EBs, we show for the first time that BM formation directs the assembly of an adhesion complex, which serves as a signaling platform to regulate epiblast polarization and survival. Our preliminary data supporting this idea, demonstrating that (1) assembly of the BM-associated adhesion complexes correlates with the activation of Rho GTPases Cdc42 and Rac1; (2) Cdc42 controls microtubule organization and the trafficking of apical polarity proteins, processes that are required for cell elongation and polarization; and (3) Rac1 activation plays an essential role in BM-dependent epiblast survival. These data strongly support our hypothesis that BM formation induces epiblast polarization and promotes epiblast survival via activation of Cdc42 and Rac1. To test this hypothesis, we propose to determine the mechanism through which the assembly of BM-associated adhesion complexes induces Cdc42 and Rac1 activation (Specific Aim 1 and 3). Next, we will determine the Cdc42-effector interactions that regulate epiblast elongation and apical polarization, focusing on the role of IQGAP1 in microtubule capture and the exocyst in apical polarity protein trafficking (Specific Aim 2). Finally, we will determine the Rac1- effector interactions that regulates epiblast survival (Specific Aim 4). The long-term goal of this study is to identify the extracellular cues and the transmembrane cascades that regulate embryonic epithelial morphogenesis, which are crucial to our understanding of epithelial biology, embryogenesis, and tissue regeneration. Elucidating the molecular mechanisms of embryonic epithelial tissue formation that integrate cellular polarity, differentiation and survival with tissue architecture is not only critical to our understanding of embryonic development and cancer biology but also has implications in tissue regeneration and tissue engineering.

极化上皮的形成是胚胎发育的基础。在小鼠周围着床发育时，囊胚的未分化内细胞团由非极性细胞聚集成高度组织化的上皮囊肿。这种形态发生转变涉及外胚层上皮的极化和基底膜（BM）依赖性存活。然而，这些过程背后的分子机制很大程度上是未知的。体外培养的胚状体可以重现小鼠植入周围的发育（EB）从胚胎干细胞分化而来。使用转基因 EB，我们首次展示了 BM 形成指导粘附复合物组装的时间，该复合物充当信号传导调节外胚层极化和存活的平台。我们的初步数据支持这个想法，证明 (1) BM 相关粘附复合物的组装与激活 Rho GTPases Cdc42 和 Rac1； (2) Cdc42控制微管组织和顶端极性蛋白的运输，细胞伸长和极化所需的过程； (3) Rac1 激活在 BM 依赖性外胚层存活中发挥重要作用。这些数据强烈支持我们的假设，即 BM 形成诱导外胚层极化并促进外胚层存活通过激活 Cdc42 和 Rac1。为了检验这个假设，我们建议确定机制 BM 相关粘附复合物的组装可诱导 Cdc42 和 Rac1 激活（具体目标 1 和 3）。接下来，我们将确定调节外胚层的 Cdc42 效应子相互作用伸长和顶端极化，重点关注 IQGAP1 在微管捕获和顶端极性蛋白质运输中的胞外囊（具体目标 2）。最后，我们将确定 Rac1- 调节外胚层存活的效应器相互作用（具体目标 4）。这项研究的长期目标是确定细胞外信号和跨膜级联调节胚胎上皮形态发生，这对于我们理解上皮细胞至关重要生物学、胚胎发生和组织再生。阐明整合细胞的胚胎上皮组织形成的分子机制组织结构的极性、分化和存活不仅对于我们理解胚胎发育和癌症生物学，而且对组织再生和组织也有影响工程。