Mechanism of ephrin signaling in mammalian palatal fusion

哺乳动物腭融合中肝配蛋白信号传导机制

• 批准号: 8766255
• 负责人: M. Douglas Benson
• 金额: $ 38.97万
• 依托单位: TEXAS A&M UNIVERSITY HEALTH SCIENCE CTR
• 依托单位国家: 美国
• 财政年份: 2014
• 资助国家: 美国
• 起止时间: 2014-07-01 至 2019-03-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8766255
• 关键词: Affect; Apoptosis; Binding; Carcinoma; Caspase; Cell Culture Techniques; Cell Nucleus; Cells; Cleft Palate; Complementary DNA; Congenital Abnormality; Cytoplasm; Cytoplasmic Tail; Data; Deformity; Development; Developmental Process; Disseminated Malignant Neoplasm; Ephrin B Receptor; Ephrin-B1; Ephrin-B2; Ephrins; Epithelial; Epithelial Cell Junction; Epithelial Cells; Epithelium; Failure; Future; Gene Proteins; Goals; Healed; Health; Image; Immigration; In Situ; Inositol; Knock-out; Knockout Mice; Knowledge; Label; Lead; Learning; Libraries; Ligands; Malignant Neoplasms; Medial; Mediating; Mesenchymal; Mesenchyme; Molecular; Molecular Target; Mus; Mutate; Neoplasm Metastasis; Operative Surgical Procedures; Palate; Pathway interactions; Phosphatidylinositols; Phosphotransferases; Play; Positioning Attribute; Proteins; Role; Secondary Palate; Signal Pathway; Signal Transduction; Signal Transduction Pathway; Signaling Protein; Testing; Time; Tyrosine; Up-Regulation; Work; base; cancer cell; cell motility; craniofacial; epithelial to mesenchymal transition; healing; in vivo; migration; palatal fusion; palatal shelves; public health relevance; research study; response; transcription factor; transforming growth factor beta3; yeast two hybrid system

DESCRIPTION (provided by applicant): Failure of the secondary palate to fuse at midline causes cleft palate, a frighteningly common birth defect that can only be treated with surgery and poses a tremendous health burden. Our long-term goal is to understand the mechanism of palatal fusion so as to better treat cleft palate. Transforming growth factor beta-3 (Tgfss3) is thought to be required to form a fused palate of confluent mesenchyme by causing degradation of the midline epithelial seam (MES) between palatal shelves. However, we recently discovered that activated ephrin-B signaling is necessary and sufficient to cause fusion in the absence of Tgfss3. Ephrin reverse signaling causes epithelial-to-mesenchymal transition (EMT) in cultured palate epithelial cells via a mechanism involving phosphotidyl inositol-3 kinase (PI3K). Because ephrins are also known to mediate programmed cell death, and apoptosis is a major part of the fusion mechanism, we propose the hypothesis that ephrin signaling causes palatal fusion through induction of EMT and apoptosis in palatal epithelia. We will test this hypothesis through pursuit of three aims. First, we will use our discovery that ephrin-B2 marks MES cells in fusing palates to track the fate of these cells in real time with confocal imaging. Second, we will determine how the known ephrins in the palate contribute to the epithelial-mesenchymal interactions that govern MES cell migration and apoptosis. Third, we will learn the molecular mechanism of ephrin reverse signaling in fusion by discovering: 1) the signaling proteins that interact with the ephrin cytodomain, 2) the specific PI3K pathway intermediates that transduce the ephrin signal, and 3) the intersection points in the cytoplasm and the nucleus between the ephrin and the known Tgfss3 signaling pathways in palatal epithelium.

描述（由申请人提供）：第二腭未能在中线融合导致腭裂，这是一种非常常见的出生缺陷，只能通过手术治疗，并造成巨大的健康负担。我们的长期目标是了解腭融合的机制，以便更好地治疗腭裂。转化生长因子β-3（Tgfss 3）被认为是通过引起腭架之间的中线上皮缝（MES）降解而形成融合间充质的融合腭所必需的。然而，我们最近发现，激活肝配蛋白-B信号是必要的，足以在Tgfss 3的情况下引起融合。肝配蛋白反向信号通过涉及磷脂酰肌醇-3激酶（PI 3 K）的机制在培养的腭上皮细胞中引起上皮向间充质转化（EMT）。由于ephrin也被称为介导程序性细胞死亡，细胞凋亡是融合机制的主要部分，我们提出的假设，ephrin信号通过诱导腭上皮细胞的EMT和细胞凋亡引起腭融合。我们将通过追求三个目标来检验这一假设。首先，我们将利用我们的发现，肝配蛋白-B2标记MES细胞融合腭跟踪这些细胞的命运在真实的时间与共聚焦成像。其次，我们将确定腭中已知的肝配蛋白如何促进上皮间充质相互作用，支配MES细胞迁移和凋亡。第三，我们将通过发现：1）与ephrin胞质结构域相互作用的信号蛋白，2）抑制ephrin信号的特异性PI 3 K通路中间体，和3）在腭上皮中ephrin和已知的Tgfss 3信号通路之间的细胞质和细胞核中的交叉点，来了解融合中ephrin反向信号传导的分子机制。