Role of Lumican in the Cornea

描述(申请人提供)：Lumcan是角膜基质中的一种主要的硫酸角蛋白多糖，长期以来一直被怀疑，现在证实在角膜透明度中发挥关键作用。基因靶向的流明蛋白缺陷小鼠在角膜基质中形成异常粗大和紊乱的胶原纤维，从而导致角膜混浊。新的证据清楚地表明，LUMICAN正在调节基质细胞的功能，并可能是ECM到细胞信号机制的关键组成部分。细胞功能包括基因表达、凋亡、增殖、附着和迁移，最终影响基质细胞外基质(ECM)结构的发育和创伤后的再生。 本研究的目的是确定LUMICAN在调节基质基因表达和合成基质细胞外基质的角质细胞的细胞行为中所起的作用。前两个目标旨在确定Lumcan在调节角质细胞功能中的作用，角质细胞功能对基质的发展和修复至关重要。第一个目标是使用野生型和鲁米肯缺失的角膜成纤维细胞来研究鲁米肯在调节培养中的细胞凋亡、增殖、附着和迁移中的作用，并确定是否使用了转化生长因子β或表皮生长因子介导的途径。第二个目的是探讨其在体内对角膜创伤愈合过程中角膜基质细胞功能的影响。第三个目标将集中在LUMICAN在调节基因表达方面的作用。无流明蛋白的角膜将被用来解决哪些基质成分在转录本和蛋白质水平上表达不同，以解释它们更薄的基质和减少的ECM。最后，LUMICAN缺失的小鼠表型强调LUMICAN是表型相似的角膜营养不良的一个强有力的候选基因。某些角膜扁平和角膜营养不良病例将被筛查有无发光性突变。一旦检测到这样的突变，鲁米肯零基因小鼠将成为解释定义角膜这些广泛变化的基因表达二次变化的首选动物模型。这项研究将为Lumcan在调节细胞功能中的作用提供新的见解，并提供对细胞外基质影响角膜发育、修复和角膜营养不良患者功能障碍的细胞信号的基本了解。

DESCRIPTION (provided by applicant): Lumican is a major keratan sulfate proteoglycan of the corneal stroma, long suspected and now confirmed to play a pivotal role in corneal transparency. Gene targeted lumican-deficient mice develop abnormally thick and disorganized collagen fibrils in the corneal stroma and consequent corneal opacity. Emerging evidence is now clearly indicating that lumican is regulating stromal cellular functions, and may be a key component of the ECM-to-cell signaling mechanisms. The cellular functions include gene expression, apoptosis, proliferation, attachment and migration, that ultimately impact stromal extracellular matrix (ECM) structure during its development and regeneration after wounding. The purpose of the current study is to determine the role played by lumican in regulating stromal gene expression and cellular behavior of the keratocytes that synthesize the stromal ECM. The first two aims are directed towards defining lumican's role in regulating keratocyte functions crucial to the development and repair of the stroma. The first aim will use wild type and lumican-null corneal fibroblasts to investigate lumican's role in regulating apoptosis, proliferation, attachment and migration in culture and determine if TGF beta or EGF mediated pathways are being used. The second aim will explore its influence on these keratocyte functions in corneal wound healing in vivo. The third aim will focus on lumican's role in regulating gene expression. The lumican-null corneas will be used to address what stromal components are expressed differently, at the transcript and at protein, levels to explain their thinner stroma and reduced ECM. Finally, the lumican-null mouse phenotype emphasizes lumican as a strong candidate gene for phenotypically similar corneal dystrophies. Certain Cornea plana and corneal dystrophy cases will be screened for lumican mutations. Once such a mutation is detected, the lumican-null mouse will be an animal model of choice to elucidate secondary changes in gene expression that define these broad changes in the cornea. This study will lead to novel insights into lumican's role in regulating cellular functions and provide a fundamental understanding of ECM to cell signaling that affect corneal development, repair and dysfunctions in corneal dystrophies.