Ocular surface epithelial precursors

眼表面上皮前体细胞

• 批准号: 8232010
• 负责人: JOSE MARIO WOLOSIN
• 金额: $ 42.38万
• 依托单位: ICAHN SCHOOL OF MEDICINE AT MOUNT SINAI
• 依托单位国家: 美国
• 财政年份: 2005
• 资助国家: 美国
• 起止时间: 2005-01-15 至 2016-02-29
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8232010
• 关键词: Affect; Autoimmune Process; Basal Cell; Biological Preservation; Blindness; Calcium; Cell Cycle; Cell Separation; Cell Survival; Cells; Chemical Injury; Clonality; Cornea; ES01; Epithelial; Epithelial Cells; Epithelium; Event; Fostering; Funding; G0 Phase; Gene Expression; Gene Expression Microarray Analysis; Gene Expression Profile; Generic Drugs; Genes; Genetic; Genetic Transcription; Goals; Grant; Growth; Human; In Vitro; Infection; Knowledge; Lead; MEIS1 gene; MSX1 gene; MXD1 gene; Mammals; Methodology; Nature; Operative Surgical Procedures; Outcome; Phenotype; Phosphorylation; Population; Procedures; Proteins; Reaction; Recovery of Function; Regulation; Relative (related person); Running; SELE gene; SP1 gene; Side; Signal Pathway; Signal Transduction; Stem cell transplant; Stem cells; Surface; Syndrome; System; Techniques; Testing; Tissue-Specific Gene Expression; Tissues; Transplantation; Vision; Work; base; cell behavior; cohort; comparative; corneal epithelium; heat injury; homeodomain; improved; in vivo; insight; limbal; microbial; ocular surface; overexpression; precursor cell; protein expression; public health relevance; reconstruction; response; restoration; stem; stem cell niche; stem cell population; stemness; tissue reconstruction

DESCRIPTION (provided by applicant): Small populations of stem cells sustain the limbal-corneal and the conjunctival lineages. In the limbal-corneal system, where stem cells localize preferentially to the limbus, total or zonal damage produces epithelial limbal stem cell deficiency syndromes. In recent years, a variety of surgical stem cell transplant methodologies have been applied to reestablish the limbal stem cell niche for vision restoration. The long term goals of our studies are a) understand the functional nature of ocular surface stem cells, in particular those of the limbus; and b) apply this critical knowledge for the optimization of ex vivo limbal cell population expansion to improve surface reconstructive procedures based on transplantation of stem cell-rich cell populations. During the initial funding period of this grant we characterized small stem cell cohorts known as side populations (SPs) from both conjunctival and limbal epithelia. Our studies showed that these cells derive from cells that have been in the slow cycling state in vivo and to display several other features recognized for stem cells in vitro. Based on finding during this period we now propose, in Specific Aim1 to test the hypothesis that cell cohorts expressing CD62E or excluding mitotrakcker deep red constitute additional component of an heterogeneous stem/precursor limbal and conjunctival epithelial cell population and in Specific Aim2 to test the hypothesis that observed overexpressions of several genes capable of affecting gene transcription globally and usually referred as master or cell fate genes (PAX6, MEIS1, SIX1, MSX1, HES1 ID1, the MXD1/MAX system controlling MYC activity) contribute to cell stemness in the limbal epithelium. The knowledge acquired in the comparative characterization of the cell cohorts associated with the stem/precursor cell compartment in Aim 1, combined with the identification of gene expressions and signal pathways that are associated with preservation or loss of the stem/precursor cell state in Specific Aim 2, will provide the cogent basis to improve strategies for either maximization of stem/precursor cell yields during limbal cells expansion in vitro, or alternatively, facilitate stem cell rescue from generic proliferative (basal) epithelial cells through reversion of phenotype for the benefit of reconstructive ocular surface procedures. Specific aim 3 seeks to apply the knowledge and expertise acquired in the two previous specific aims for the genetic and/pharmacological manipulation of freshly isolated limbal epithelial cells to attain effective expansion of these cells while maintaining their capacity for corneal epithelial function recovery in vivo. PUBLIC HEALTH RELEVANCE: Damage to the limbus by chemical or thermal injuries, microbial infection, or autoimmune reactions result in limbal stem cell deficiencies (LSCD) causing visual loss and blindness. Transplants with expanded limbal cell populations incorporating stem cells can restore or improve vision. We now propose a roadmap to test the impact of genes identified in these stem cells on their phenotype and survival and to apply the gained insight to increase the content of stem cells in expanded limbal populations and thereby improve the outcome of corneal reconstruction surgeries.

描述（由申请人提供）：少量干细胞维持角膜缘和结膜谱系。在角膜缘-角膜系统中，干细胞优先定位于角膜缘，完全或区域性损伤会产生上皮角膜缘干细胞缺乏综合征。近年来，各种外科干细胞移植方法已被应用于重建角膜缘干细胞生态位以恢复视力。我们研究的长期目标是 a) 了解眼表干细胞的功能性质，特别是角膜缘的干细胞； b) 应用这一关键知识来优化离体角膜缘细胞群扩增，以改进基于富含干细胞的细胞群移植的表面重建程序。在这笔赠款的初始资助期间，我们对来自结膜和角膜缘上皮的称为侧群（SP）的小型干细胞群进行了表征。我们的研究表明，这些细胞源自体内处于慢循环状态的细胞，并在体外表现出干细胞公认的其他几个特征。基于这一时期的发现，我们现在提出，在特定目标1中检验表达CD62E或排除mitotrakcker深红色的细胞群构成异质干/前体角膜缘和结膜上皮细胞群的附加成分的假设，并在特定目标2中检验观察到能够全局影响基因转录的几个基因的过度表达（通常称为主细胞或细胞命运）的假设 基因（PAX6、MEIS1、SIX1、MSX1、HES1 ID1、控制 MYC 活性的 MXD1/MAX 系统）有助于角膜缘上皮的细胞干性。在目标 1 中与干/前体细胞区室相关的细胞群的比较表征中获得的知识，结合特定目标 2 中与干/前体细胞状态的保存或丢失相关的基因表达和信号通路的识别，将为改进在体外扩增角膜缘细胞期间干/前体细胞产量最大化的策略提供有力的基础，或者促进干细胞从通用条件下的拯救 通过表型逆转来增殖（基底）上皮细胞，以利于眼表重建手术。具体目标3旨在应用在前两个具体目标中获得的知识和专业知识，对新鲜分离的角膜缘上皮细胞进行遗传和/药理学操作，以实现这些细胞的有效扩增，同时保持其体内角膜上皮功能恢复的能力。 公共健康相关性：化学或热损伤、微生物感染或自身免疫反应对角膜缘造成的损伤会导致角膜缘干细胞缺陷 (LSCD)，从而导致视力丧失和失明。移植含有干细胞的扩大的角膜缘细胞群可以恢复或改善视力。我们现在提出了一个路线图，以测试这些干细胞中识别的基因对其表型和存活的影响，并应用所获得的见解来增加扩大的角膜缘群体中干细胞的含量，从而改善角膜重建手术的结果。