Expression Programs of Intestinal Cell Differentiation

描述(申请人提供)：肠道上皮细胞在整个生命过程中经历快速和持续的细胞更新。这种自我更新是由位于肠道隐窝的一组多能干细胞维持的。这些干细胞产生祖细胞，然后祖细胞分化成不同的细胞系，并沿着肠道绒毛向上迁移。这种分化过程的分子遗传学仍未得到很好的解释。肠道干细胞为一些胃肠道疾病，如炎症性肠病和肠衰竭提供了很有前景的治疗策略。然而，对这些干细胞的特异性标志物知之甚少，这使得干细胞的分离和体外培养变得困难。我们假设有不同的基因表达程序与肠道的发育程序相关，即肠道绒毛的不同区域具有不同的表达谱。我们进一步假设，位于肠道隐窝一侧的干细胞与人类胚胎干细胞具有相似的“严厉”基因。在这一应用中，我们提出了以下目标：目的1：获得肠绒毛不同区域的基因表达谱；目标2：鉴定与肠上皮不同区域相关的基因，以及可能与肠干细胞相关的基因；目标3：验证候选基因的表达并研究其细胞定位。总之，拟议的与肠上皮细胞相关的基因表达模式的探索性研究将为这些细胞的分化程序提供一个全面的图景。此外，可能与肠道干细胞相关的基因将为这些细胞的鉴定、纯化和表征提供标记。

DESCRIPTION (provided by applicant): Intestinal epithelial cells undergo rapid and continuous cell renewal through out life. This self-renewal is maintained by a group of multipotent stem cells located at intestinal crypts. These stem cells give rise to progenitor cells, which then differentiate into different cell lineages and migrate up along the intestinal villi. Molecular genetics of this differentiation process is still poorly defined. Intestinal stem cells provide promising treatment strategy for some GI diseases, for example, inflammatory bowel disease and gut failure. However, little is known of specific markers for these stem cells, which make the isolation and culture of the stem cells difficult in vitro. We hypothesize that there are distinct gene expression programs that are associated with the developmental program of the intestine, i.e., different regions of the intestinal villi have different expression profiles. We further hypothesize that the stem cells located in the crypt side of the intestine share similar "sternness" genes with human embryonic stem cells. In this application, we propose the following aims: Aim 1: To obtain a gene expression profile of different regions of intestinal villi; Aim 2: To identify genes that are associated with different regions of intestinal epithelium, as well as genes that may be related to the intestinal stem cells; and Aim 3: To validate the expression and study the cellular localization of candidate genes. In summary, the proposed exploratory study of gene expression patterns associated with intestinal epithelial cells will provide a comprehensive picture of the differentiation program of these cells. Moreover, the genes that may be associated with intestinal stem cells will provide markers for identification, purification and characterization of these cells.