An integrated experimental and theoretical approach to understanding corneal epithelial maintenance

维护角膜是正常视力所必需的，角膜是眼睛的透明前表面，是我们了解世界的窗口。有许多方式可能会永久损害它，导致不透明和潜在的视力丧失。尽管许多实验室进行了密集的研究，但与维护角膜表面有关的主要问题仍然存在。例如，尽管存在大量证据表明干细胞发挥着重要作用，但这些干细胞的实际位置，以及它们在什么程度和什么情况下活跃，仍然存在极大的争议。同样，尽管人们知道细胞在角膜中的整个生命过程中都会发生迁移，但它的重要性甚至它的方向一直存在争议。由于角膜表面的维持对我们的视力至关重要，因此我们必须了解角膜的正常功能以及在短期和长期内对损伤的反应的基本生物学。本项目将解决角膜表面上皮内干细胞的定位和活性、细胞生产、迁移和丢失等重要问题。我们将建立一个我们已经开发的计算机模型，该模型潜在地解释了我们之前观察到的一些细胞迁移和丢失的模式。我们将使用新的生物数据来完善这一模型，然后用它来对角膜如何正常维护、它如何受到老化和遗传缺陷的影响以及它对损伤的反应做出可测试的预测。我们有一系列的“报告”小鼠，因为它们在它们的角膜上皮细胞亚群中表达荧光或其他化学标记，可以用来追踪从怀孕到成年的整个生命过程中角膜细胞生产和迁移的模式。使用这些小鼠，我们将能够模拟遗传异常和角膜损伤，以检验计算机模型的预测。这些小鼠将被用来显示干细胞在角膜中的位置--这一知识对于我们理解上皮是如何维持的至关重要。他们将展示损伤和遗传缺陷如何改变角膜表面正常的细胞生产和迁移模式，并揭示这些变化是长期的还是短期的。干细胞活性和迁移模式随年龄的变化也将通过这些小鼠来确定--例如，众所周知，老化的人类角膜比年轻人的角膜愈合得更慢。改进后的模型将具有持久的好处，因为我们将能够使用它来预测不同类型的异常如何在不同的角膜疾病中发生。这也将有助于减少未来的动物实验。总体而言，该项目将对正常生活中角膜维护的基础过程产生关键的基本理解。我们将能够确定干细胞在哪里，它们起什么作用，以及替代细胞如何到达损伤部位。这些知识也将帮助我们理解为什么角膜表面有时会出现难以治疗的退化和混浊。如果我们的动物研究的新见解适用于人类，这也可能改善角膜疾病或手术引起的并发症的管理，如激光眼科手术。

Maintenance of the cornea, the transparent front surface of the eye that acts as our window on the world, is necessary for normal vision. There are many ways in which it can get permanently damaged, leading to opacity and potential loss of sight. In spite of intense study by many laboratories, major questions relating to the maintenance of the corneal surface remain. For example, although a large body of evidence exists which implies that stem cells have a major role, the actual location of these stem cells, and to what extent and under what circumstances they are active, remains highly controversial. Similarly, while it is known that cell migration occurs throughout life in the cornea, its importance and even its direction have been disputed. Because maintenance of the corneal surface is fundamental to our eyesight it is essential that we understand the basic biology about how the cornea functions normally and reacts, in the short and long term, to injury.This project will address the significant issues about stem cell localisation and activity, cell production, migration and loss, within the corneal surface epithelium. We will build upon a computer model that we have already developed that potentially explains some of the patterns of cell migration and loss that we have previously observed. We will refine that model using new biological data, and then use it to make testable predictions about how the cornea is maintained normally, how it is affected by ageing and genetic defects and how it responds to injury. We have an array of 'reporter' mice which, because they express fluorescent or other chemical markers in subsets of their corneal epithelial cells, can be used to trace patterns of cell production and migration in the cornea throughout life, starting during gestation and continuing into the ageing adult. Using these mice, we will be able to model genetic abnormalities and corneal injuries that test the predictions of the computer model. The mice will be used to show where the stem cells are localised in the cornea - knowledge that is essential to our understanding of how the epithelium is maintained. They will show how normal patterns of cell production and migration in the corneal surface are changed by injury and genetic defects, and also reveal whether these changes are long or short term. Changes in stem cell activity and migration patterns with ageing will also be determined using these mice - it is known for example that ageing human corneas heal less quickly than those from younger people. The refined model will have lasting benefits, as we will be able to use it to predict how different types of abnormalities occur in different corneal diseases. It will also contribute to reducing future animal experiments. Overall the project will generate key fundamental understanding of the processes that underlie corneal maintenance during normal life. We will be able to determine where the stem cells are, what they do and how replacement cells get to sites of injury. This knowledge will also help us understand why the corneal surface sometimes suffers degeneration and opacification that is difficult to treat. If new insights from our animal studies are applicable to humans this may also improve the management of corneal diseases or complications arising from operations such as laser eye surgery.