Roles of Growth Factors on Corneal Morphogenesis

生长因子对角膜形态发生的作用

• 批准号: 6781086
• 负责人: WINSTON W KAO
• 金额: $ 38.86万
• 依托单位: UNIVERSITY OF CINCINNATI
• 依托单位国家: 美国
• 财政年份: 2002
• 资助国家: 美国
• 起止时间: 2002-07-01 至 2006-06-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6781086
• 关键词: cell differentiation; cell migration; cell proliferation; conjunctiva; cornea disorder; corneal endothelium; corneal epithelium; corneal stroma; eyelids; fibroblast growth factor; gene expression; genetically modified animals; histogenesis; homeostasis; immunocytochemistry; in situ hybridization; laboratory mouse; mesenchyme; microarray technology; neural crest; polymerase chain reaction; reporter genes; terminal nick end labeling; transforming growth factors; western blottings; wound healing

Morphogenesis of cornea, conjunctiva and eyelids during vertebrate eye development involves the migration of mesenchymal cells of neural crest origin and the differentiation of cells of the surface ectoderm. The bi-directional mesenchyme-epithelium interactions via growth factors are essential for morphogenesis during development and homeostasis in adults. TGF-betas and FGF- 7 play pivotal roles in modulating functions of mesenchymal cells of neural crest origin and differentiation of ectoderm cells during ocular morphogenesis. These functions are exemplified by severe clinical manifestations observed as follows: in Tgfb2-/- mice resembling Axenfeld-Reiger's anomaly in human; by biglycan transgenic (KeraprBgn/+) mice of keratocan promoter (Kerapr) exhibiting secondary limbal deficiency; and by FGF-7 transgenic mice of alphaA-crystalline promoter (alphaACpr) resulting in conjunctivalization of corneal surface. These observations raise intriguing questions such as: 1). When do mesenchymal cells commit to becoming endothelial cells? 2). Are eyelid stromal cells also of neural crest origin? 3). What is the role of TGF- beta and FGF-7 signaling in eye development and corneal homeostasis and wound healing? 4). What are the molecular and cellular mechanisms of phenotypes observed in KeraprBgn/+ transgenic mice? To address these questions, we will create tetracycline inducible transgenic mouse models that overexpress the dominant negative mutant of type II TGF-beta receptor, active TGF-beta1 and FGF-7 under the control of Kerapr, and FGF-7 under the control of alphaCApr. With these models we will examine the role of TGF-beta signaling on corneal morphogenesis during development and homeostasis and further characterize the KeraprBgn/+ mice to examine the hypothesis that excess biglycan perturbs TGF-beta signaling during eyelid morphogenesis. Specific Aim 1 is to elucidate roles of TGF-beta signaling on eye morphogenesis during development, homeostasis and wound healing using tet-O TbetaRIIdn/+ KeraprrtTA/+ and tet-O TGFbeta1/+ KeraprrtTA/+ mice. Specific Aim 2 will elucidate ocular surface epithelial differentiation using alphaACprrtTA/+ tet-OFGF7/+ and KeraprrtTA/+ tet-OFGF7/+ mice that overexpress FGF-7. Specific Aim 3 will Elucidate the Role of Excess Biglycan on Eyelid Formation during Development of KeraprBgn/+ mice. The proposed studies will yield useful information for a better understanding of the role of TGF-beta and FGF-7 on corneal development and homeostasis, leading to the design of better treatments for corneal diseases, e.g., epithelial debridement, incision, alkali burn.

脊椎动物眼球发育过程中，角膜、结膜和眼睑的形态发生涉及神经脊来源的间充质细胞的迁移和表面外胚层细胞的分化。通过生长因子的双向间充质-上皮相互作用对于成人发育过程中的形态发生和动态平衡是必不可少的。在眼形态发生过程中，转化生长因子-β1和成纤维细胞生长因子-7在调节神经沟来源的间充质细胞的功能和外胚层细胞的分化过程中起着关键作用。这些功能的严重临床表现如下：在Tgfb2-/-小鼠中，类似于人类的Axenfeld-Reiger‘s畸形；由转角蛋白聚糖启动子(KeraprBgn/+)的Biglycan转基因(KeraprBgn/+)小鼠表现出继发性角膜缘缺陷；以及由成纤维细胞生长因子-7转基因小鼠的αA-晶体启动子(AlphaACpr)导致角膜表面结膜形成。这些观察提出了一些耐人寻味的问题，例如：1)。间充质细胞何时承诺成为内皮细胞？2)。眼睑基质细胞是否也起源于神经脊？转化生长因子-β和成纤维细胞生长因子-7信号在眼发育、角膜动态平衡和伤口愈合中起什么作用？在KeraprBgn/+转基因小鼠中观察到的表型的分子和细胞机制是什么？为了解决这些问题，我们将建立四环素诱导的转基因小鼠模型，该模型在Kerapr控制下过量表达II型转化生长因子-β受体的显性阴性突变体，在Kerapr控制下高表达活性的转化生长因子-β1和成纤维细胞生长因子-7，在α-CApr控制下过表达成纤维细胞生长因子-7。通过这些模型，我们将研究在发育和动态平衡过程中转化生长因子-β信号在角膜形态发生中的作用，并进一步描述KeraprBgn/+小鼠，以检验在眼皮形态发生过程中过量的双聚糖干扰转化生长因子-β信号的假说。具体目的1是利用tet-O TbetaRIIdn/+KeraprrtTA/+和tet-O TGFbeta1/+KeraprrtTA/+小鼠，阐明转化生长因子-β信号在眼睛发育、动态平衡和伤口愈合中的作用。特殊目的2将使用过表达成纤维细胞生长因子-7的alphaACprrtTA/+tet-OFGF7/+和KeraprrtTA/+tet-OFGF7/+小鼠阐明眼表上皮细胞分化。具体目标3将阐明在KeraprBgn/+小鼠发育过程中过量的Biglycan对眼皮形成的作用。建议的研究将为更好地了解转化生长因子-β和成纤维细胞生长因子-7在角膜发育和动态平衡中的作用提供有用的信息，从而设计出更好的治疗角膜疾病的方法，如上皮清创、切开、碱烧伤。