Corneal Innervation and Epithelial Cell Migration

角膜神经支配和上皮细胞迁移

• 批准号: 7189076
• 负责人: JES K KLARLUND
• 金额: $ 37.13万
• 依托单位: UNIVERSITY OF PITTSBURGH AT PITTSBURGH
• 依托单位国家: 美国
• 财政年份: 2003
• 资助国家: 美国
• 起止时间: 2003-02-01 至 2009-01-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7189076
• 关键词: 1-Phosphatidylinositol 3-Kinase; Activator Appliances; Agonist; Binding; Biological Assay; Blindness; Cartoons; Cell membrane; Chemotactic Factors; Chemotaxis; Complement Factor B; Complex; Cornea; Corneal Injury; Defect; Disruption; Doctor of Philosophy; Dominant-Negative Mutation; Drug Delivery Systems; Epithelial; Epithelial Cells; Epithelium; Factor Analysis; Failure; GTP Binding; GTP-Binding Proteins; Generations; Growth Cones; Health; Hormones; Immigration; Injury; Lead; Lipids; MDCK cell; Maintenance; Modeling; Molecular; Movement; NGFR Protein; Nerve Fibers; Nerve Growth Factor Receptors; Nerve Growth Factors; Neurites; Neurons; Numbers; Pathway interactions; Perforation; Principal Investigator; Protein Overexpression; Proteins; Purpose; Recruitment Activity; Role; Signal Pathway; Signal Transduction; Signaling Molecule; Site; Stem cells; Stimulus; Surface; Testing; Ulcer; Wound Healing; afferent nerve; cell growth; cell motility; corneal epithelium; expectation; inhibitor/antagonist; migration; mutant; nerve supply; neurotropic; ocular surface; programs; receptor; repaired

DESCRIPTION (provided by applicant): Maintenance of the normal corneal epithelium requires constant centripetal migration of corneal epithelial cells derived from stem cells in the limbus. Maintenance of the epithelium is also dependent on presence of sensory nerve fibers in the cornea and their extension after wounding. Defective corneal innervation commonly results in epithelial defects or neurotropic ulcers and blindness. Our long-term objective is to understand the mechanisms that drive corneal epithelial cell migration and extension of neurites in the cornea upon wounding, and how corneal epithelium and corneal neurons interact. Current evidence points to a critical role for PI 3 kinase in corneal epithelial cell migration. We have recently isolated a target for PI 3 kinase, GRP1, and an associated protein GRSP1. GRP1 is an activator for the small GTP binding protein ARF6, which has been shown to regulate extension of lamellipodia and cell movement. The organizing hypothesis for this proposal is that upon activation, the receptors for nerve growth factor and for chemotaxtic stimuli activate PI-3 kinase, which produces the lipid messenger PIP3. As a result GRP1 is recruited to the plasma membrane and activates ARF6, which causes formation of lamellipodia at the leading edge of migrating corneal epithelial cells and in the growth cones of corneal nerve fibers. We will test the following hypotheses: 1) GRP1 is a necessary component of the signaling pathway leading from agonist stimulation to migration of corneal epithelial cells and neurite extension; 2) GRP1 functions as part of a complex with GRSP1 and 3) ARF6 is also a necessary component of the signaling pathway. The approaches will include determination of the activation states of the signaling molecules upon stimulation with chemotactic and neurogenic factors, analysis of the effects of stimulating or blocking the pathway at different steps, and attempts to rescue the signaling pathway after introduction of a block by inhibitors or dominant negative constructs.

描述（由申请方提供）：正常角膜上皮的维持需要源自利姆布斯中干细胞的角膜上皮细胞持续向心迁移。上皮的维持也依赖于角膜中感觉神经纤维的存在及其在创伤后的延伸。缺陷性角膜神经支配通常导致上皮缺陷或嗜神经性溃疡和失明。我们的长期目标是了解角膜上皮细胞迁移和角膜神经突起在创伤后延伸的机制，以及角膜上皮和角膜神经元如何相互作用。 目前的证据表明PI 3激酶在角膜上皮细胞迁移中起关键作用。我们最近已经分离出PI 3激酶，GRP 1和相关蛋白GRSP 1的目标。GRP 1是小GTP结合蛋白ARF 6的激活剂，ARF 6已被证明调节板状伪足的延伸和细胞运动。该提议的组织假设是，在激活时，神经生长因子和趋化刺激的受体激活PI-3激酶，其产生脂质信使PIP 3。因此，GRP 1被募集到质膜并激活ARF 6，这导致在迁移的角膜上皮细胞的前缘和角膜神经纤维的生长锥中形成板状伪足。我们将测试以下假设：1）GRP 1是从激动剂刺激到角膜上皮细胞迁移和神经突延伸的信号通路的必要组成部分; 2）GRP 1作为与GRSP 1的复合物的一部分发挥作用; 3）ARF 6也是信号通路的必要组成部分。这些方法将包括确定在用趋化因子和神经原性因子刺激时信号分子的激活状态，分析在不同步骤刺激或阻断该通路的效果，以及在通过抑制剂或显性负性构建物引入阻断后尝试拯救信号通路。