Molecular mechanism of corneal epithelial stratification and innervation

项目摘要/摘要 角膜上皮(CE)由单层基底细胞和4-5层非角膜上皮细胞组成。 角化、复层鳞状上皮细胞形成有效的屏障，防止液体流失和 病原体。CE主要由密度极高的三叉神经感觉神经传入支配， 它对环境侮辱提供了极大的敏感性，以保护其他更深层次的 通过调节眨眼反应和刺激泪水来保护眼睛组织免受损害。任何 CE分层和神经支配的破坏可能会对大脑中动脉的完整性产生有害影响 并导致神经营养性角膜病变和角膜失明。人们对此知之甚少 CE层化和神经支配的分子和细胞机制 角膜形态发生并持续存在于成年期。在这项提案中，我们试图 探讨Shp2介导的RAS-MAPK信号转导途径 对于各种各样的细胞活动和行为极其重要，但还没有被研究过 在CE的分层和支配中。我们假设Shp2介导的MAPK信号转导 通过调节∆Np63的表达来控制CE的层积和神经支配。三个目标是 建议： 目的1阐明Shp2、→、RAS、→、MEK、→∆、Np63、→、E-钙粘素信号通路在心肌梗死中的作用。 发育过程中及之后的角膜上皮分层。 目的2阐明CE的Shp2、→、RAS、→、MEK、→∆、Np63、→、NGF信号轴在细胞周期调控中的作用。 CNV1在发育过程中及之后的神经支配。 目标3是通过过度表达来挽救原本受损的CE分层和神经支配 ∆Np63α在Shp2cko小鼠体内的表达。 建议目标的完成将描述与Shp2介导的 Ras-MAPK通路微调∆Np63，进而调节E-钙粘素和神经生长因子，从而促进 CE在角膜发育和维持过程中的分层和神经支配 动态平衡。这一知识具有巨大的潜力，有助于发现基于途径的 分子靶点用于治疗角膜疾病，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.