Regulation of Active and Quiescent Intestinal Stem Cells

描述(由申请人提供)：有新的证据表明，活跃循环和静止的不同群体的肠道干细胞(ISCs)共存于小肠上皮内，并在组织更新中协同发挥作用。这一建议探索了一种假设，即这些ISC群体受不同的细胞外信号调控，这些细胞外信号涉及器官大小控制和氧气感知。这一假说有三个特定的目的：(1)探索河马信号通路，涉及控制器官大小，调节活跃和静止的ISC群体的再生反应；(2)通过氧感应途径研究活跃和静止的ISCs的代谢调节；(3)通过比较基因表达谱来确定活跃和静止的ISCs的分子特征。这些特定的目标将通过使用严格的小鼠遗传学在体内检测干细胞区位内的ISCs和验证体外克隆培养技术来实现，该技术允许单个分离的ISCs持续增殖和多谱系分化。这些目标的实现应该有助于深入了解活跃和静止的ISCs在转录水平上的分子差异，以及它们在转录水平上的差异调控 控制器官大小和新陈代谢的不同途径。

DESCRIPTION (provided by applicant): There is emerging evidence that distinct populations of actively cycling and quiescent intestinal stem cells (ISCs) co-exist within the small intestine epithelium and function cooperatively in tissue renewal. This proposal explores the hypothesis that these ISC populations are regulated by distinct sets of extracellular signals involved in organ size control and oxygen-sensing. This hypothesis is evaluated by three Specific Aims: (1) to explore the Hippo signaling pathway, implicated in controlling organ size, in regulating the regenerative responses of active and quiescent ISC populations, (2) to examine metabolic regulation of active and quiescent ISCs by the oxygen-sensing pathway, and (3) to determine the molecular signatures of active versus quiescent ISCs by comparative gene expression profiling. These Specific Aims will be achieved by employing rigorous mouse genetics to examine ISCs in vivo within their stem cell niches and validated ex vivo clonogenic culture techniques that allow for sustained proliferation and multi-lineage differentiation of single isolated ISCs. Achievement of these Aims should provide insight into the molecular differences between active and quiescent ISCs at the transcriptional level and their differential regulation by diverse pathways governing organ size and metabolism.