EPITHELIAL/MESENCHYMAL TRANSFORMATION IN PALATOGENESIS

古生中的上皮/间质转化

• 批准号: 6144048
• 负责人: CHARLES F SHULER
• 金额: $ 20.14万
• 依托单位: UNIVERSITY OF SOUTHERN CALIFORNIA
• 依托单位国家: 美国
• 财政年份: 1999
• 资助国家: 美国
• 起止时间: 1999-08-01 至 2000-07-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6144048
• 关键词: cell growth regulation; cell population study; cell proliferation; cell type; cleft palate; congenital oral /facial /cranial defect; dental development; epithelium; gene targeting; genetically modified animals; growth factor receptors; immunocytochemistry; intracellular transport; laboratory mouse; mammalian embryology; mesenchyme; metalloendopeptidases; nucleic acid sequence; palate; receptor binding; tissue /cell culture; transforming growth factors

A critical event in the fusion of the secondary palate is the disappearance of the medial edge epithelium from the midline. Studies in our laboratory have used cell lineage analysis to trace the fate of the medial edge epithelial cells and document that these cells undergo a phenotypic transitions and remain viable as mesenchymal cells. Investigations of the molecular control of the phenotypic transformation have identified TF-beta3 as an important regulating molecule. Homozygous TGF-beta3 knock-out mice do not fuse in organ culture without supplementation of exogenouse TGF-beta3. These findings have led to the hypothesis, TGF-beta3 is a primary effectors molecule responsible for initiating the program of epithelial-mesenchymal transformation in the palatal shelf medial edge epithelial cells during palatal fusion. This hypothesis will be tested by four Specific Aims; 1. To determine the role of TGF-beta3 in the pattern of expression of cell-type specific phenotypic markers in the MEE during palatogenesis; 2. To characterize the mechanism of TGF-beta3 regulation of the cell cycle and MEE cell proliferation prior to palatal shelf contact and the onset of epithelial-mesenchymal transformations; 3. To examine the intracellular signalling pathway in the MEE following binding of the growth factor to its cell surface receptor; 4. To evaluate TGF-beta3 regulation of matrix metalloproteinases in the mesenchyme underlying the MEE responsible for degradation of the basement membrane. Identification of molecular mechanisms essential to the process of palatal fusion will result in future possible applications to determining the mechanisms underlying human craniofacial birth defects, developing prenatal diagnosis strategies, establishing familial risk of craniofacial birth defects, determining the mechanism of action of craniofacial teratogens and reducing the incidence of human craniofacial birth defects.

第二腭融合的一个关键事件是内侧边缘上皮从中线消失。我们实验室的研究使用细胞谱系分析来追踪内侧边缘上皮细胞的命运，并记录这些细胞经历表型转变并作为间充质细胞保持活力。对表型转化的分子控制的研究已确定 TF-β3 是一种重要的调节分子。如果不补充外源性 TGF-β3，纯合 TGF-β3 敲除小鼠在器官培养中不会融合。这些发现导致了这样的假设：TGF-β3是负责在腭融合过程中启动腭架内侧边缘上皮细胞的上皮-间质转化程序的主要效应分子。这一假设将通过四个具体目标进行检验； 1. 确定 TGF-β3 在腭发育过程中 MEE 中细胞类型特异性表型标记物表达模式中的作用； 2. 表征在腭架接触和上皮间质转化开始之前TGF-β3调节细胞周期和MEE细胞增殖的机制； 3. 检测生长因子与其细胞表面受体结合后MEE中的细胞内信号通路； 4. 评估 TGF-β3 对负责基底膜降解的 MEE 下方间充质中基质金属蛋白酶的调节。识别腭融合过程中必需的分子机制将在未来可能应用于确定人类颅面出生缺陷的机制、制定产前诊断策略、确定颅面出生缺陷的家族风险、确定颅面致畸剂的作用机制以及降低人类颅面出生缺陷的发生率。