Stem cell organisation and differentiation in the niche

人们期望干细胞有一天能够治愈各种各样的人类疾病。然而，干细胞疗法的发展依赖于对这些迷人细胞的生物学的正确理解。干细胞在体内占据一个特殊的环境，称为？利基？控制干细胞的行为和存活大多数人类干细胞龛位在身体深处，因此很难研究。眼睛前表面角膜的最外层有干细胞，它们生活在一个叫做利姆布斯的透明区域。我们最近在利姆布斯中发现了新的结构，我们认为这可能是干细胞的小生境。我们建议使用扫描电子显微镜和共聚焦显微镜等技术研究捐赠的人类角膜中的这些结构和与它们相关的细胞，以确定干细胞的确切位置以及它们如何发挥功能。我们还将研究年龄对干细胞及其生态位的影响。这是非常重要的，因为临床上可以对健康的利姆布斯进行小的活检，为因角膜最外层的特定损伤或疾病而失明的患者准备干细胞治疗。然而，我们和其他人在不知道最佳活检位置的情况下提供这种治疗。因此，我们的研究将改进这种手术技术。我们还必须能够为个别患者改进治疗方法，这需要了解干细胞移植后发生的情况。我们建议开发一种技术，用于标记和移植干细胞到人类角膜使用非常小的颗粒，荧光明亮，可以检测到临床仪器。使用这种方法，我们还将确定干细胞在移植后如何在小生境中组织自己，以及它们是否对小生境有任何影响。我们的数据将帮助我们了解眼睛的一个重要特征，这有助于清晰的视力（即利姆布斯中健康、功能正常的干细胞），这将有助于改善角膜的干细胞治疗。如果发现我们的数据提供了与其他人类干细胞利基的相似之处，它将支持使用容易获得和透明的角膜作为开发其他干细胞疗法的模型。

There is an expectation that stem cells will one day be able to cure a wide variety of human diseases. However, development of stem cell therapies relies upon a sound understanding of the biology of these fascinating cells. Stem cells occupy a specialised environment in the body known as a ?niche? which controls stem cell behaviour and survival. Most human stem cell niches are deep in the body and so difficult to study. The outermost layer of the cornea on the front surface of the eye has stem cells which live in a transparent area called the limbus. We have recently discovered new structures in the limbus which we believe may be the stem cell niche. We propose to study these structures and the cells associated them in donated human corneas using techniques including scanning electron and confocal microscopy determine where exactly the stem cells are and how they function. We will also study the effect of age upon the stem cells and their niche. This is very important because clinically it is possible to take a small biopsy of the healthy limbus to prepare stem cell therapy for patients blinded by specific injuries or diseases of the outermost layer of the cornea. However, we and others are providing this therapy without knowing the optimal biopsy location. Our study will therefore improve this surgical technique. We must also be able to refine treatments for individual patients which requires knowledge of what happens to the stem cells after they have been transplanted. We propose to develop a technique for labelling and transplanting stem cells onto the human cornea using very small particles which fluoresce brightly and can be detected with clinical instruments. Using this methodology we will also determine how well stem cells organise themselves in the niche after transplantation and if they have any affect upon that niche. Our data will help us to understand one of the important features of the eye which contributes to clear vision (i.e. healthy, functioning stem cells in the limbus) which will help to improve stem cell therapy for the cornea. If it is found that our data provide parallels with other human stem cell niches, it would support the use of the readily accessible and transparent cornea as a model for the development of other stem cell therapies.