Molecular mechanism of corneal epithelial stratification and innervation

项目总结/摘要 角膜上皮（CE）由单层基底细胞和4-5层非基底细胞组成， 角化的、复层的鳞状上皮细胞，以形成有效的屏障防止液体流失， 病原体CE主要由密度极高的三叉神经感觉传入神经支配， 它提供了对环境损害的巨大敏感性， 通过调节眨眼反应和刺激流泪来保护眼组织免受损伤。任何 CE分层和神经支配的破坏可能对脑组织的完整性产生有害影响。 导致神经营养性角膜病和角膜盲。关于这一点，我们知之甚少。 分子和细胞机制，CE分层和神经支配的实现， 角膜形态发生并持续到成年期。在本提案中，我们试图 探讨Shp 2介导的Ras丝裂原活化蛋白激酶（Ras-MAPK）通路， 它对细胞的各种活动和行为极其重要，但尚未被研究 CE分层和神经支配。我们假设Shp 2介导的MAPK信号通路 通过调节HCNp 63的表达来控制CE分层和神经支配。三个目标是 提议： 目的：1.阐明Shp 2 →Ras→Mek→E-cadherin →E-cadherin信号通路在肝癌细胞凋亡中的作用。 发育过程中和发育后的角膜上皮分层。 目的2：阐明CE的Shp 2 →Ras→Mek→ JNp 63 →NGF信号轴在细胞凋亡中的作用。 CNV 1在发育期间和之后的神经支配。 目的3是通过过度表达 Shp 2cko小鼠中的Np 63 α。 完成拟定目标将描述与Shp 2介导的 Ras-MAPK途径微调JNP 63，进而调节E-钙粘蛋白和NGF， 在角膜发育和维持过程中CE的分层和神经支配 体内平衡这些知识有很大的潜力，导致发现基于路径的 分子靶点治疗角膜疾病，如神经营养性角膜病变。

PROJECT SUMMARY/ABSTRACT Corneal epithelium (CE) is composed of a single layer of basal cells and 4-5 cell layers of non- keratinized, stratified squamous epithelial cells to form an effective barrier against fluid loss and pathogen. CE is mainly innervated by trigeminal sensory afferents with extremely high density, which offers enormous sensitivity to the environmental insults for protecting otherwise deeper ocular tissues from damage by modulating the blink response and stimulating lacrimation. Any disruption of CE stratification and innervation can have deleterious effects on the integrity of the cornea and lead to neurotrophic keratopathy and corneal blindness. Little is known regarding the molecular and cellular mechanisms by which CE stratification and innervation is achieved during corneal morphogenesis and continuously sustained in the adulthood. In this proposal, we attempt to explore Shp2-mediated Ras–mitogen-activated protein kinase (Ras-MAPK) pathway which is extremely important for wide variety of cellular activities and behaviors, but it has not been studied in the CE stratification and innervation. We hypothesize that Shp2-mediated MAPK signaling controls CE stratification and innervation via regulating ∆Np63 expression. Three aims are proposed: Aim 1 is to elucidate the role of Shp2→Ras→Mek→∆Np63→E-cadherin signaling pathway in corneal epithelial stratification during and following development. Aim 2 is to elucidate the role of Shp2→Ras→Mek→∆Np63→NGF signaling axis of the CE on the CNV1 innervations during and following development. Aim 3 is to rescue otherwise impaired CE stratification and innervation by overexpression of ∆Np63α in Shp2cko mice. Completion of proposed objectives will delineate mechanistic event related to the Shp2-mediated Ras-MAPK pathway to fine-tune ∆Np63, which in turn regulate E-cadherin and NGF, to faciliate stratification and innervation of CE during development and in the maintenance of corneal homeostasis. This knowledge has great potential to lead to the discovery of pathway-based molecular target to treat corneal diseases such as neurotrophic keratopathy.