Stem cell-based renewal and regeneration in the intestine of a model organism

项目简介：成人干细胞补充因正常磨损而丢失的细胞，并修复器官 和组织对伤害的反应。这种现象的一个很好的例子是哺乳动物的消化 上皮细胞，在正常情况下每3-5天完全更新一次细胞，也可以 因辐射或细胞毒性物质(如化疗)而受损的细胞。这种快速自我调整的能力 RENEW引起了人们的极大兴趣，因为它使胃肠道系统更容易患上癌症，也因为 在特定疾病背景下(例如短肠综合征)促进更新的能力将在临床上得到应用 有益的。此外，对胃肠道修复的了解可能会促进更全面的 干细胞技术在再生医学中的应用。然而，尽管最近取得了进展， 调节胃肠道干细胞维持、增殖和分化的分子机制 都没有被很好地理解。 因为它们显著的再生能力和在应用方面的许多最新进展 现代分子技术、扁平线虫是研究组织更新的极具吸引力的模式生物 和干细胞生物学。在浮游生物中，被称为新生细胞的成体干细胞在正常细胞期间补充组织 周转和受伤后再生过程中。作为动物最突出的器官之一， 浮游生物的肠道为探讨损伤的分子机制提供了一个很好的机会 以及细胞周转对干细胞增殖和谱系的限制。 这些实验建议利用现有的技术来识别由脊椎动物表达的基因。 肠道更新和再生所需的肠道上皮细胞。这项建议的具体目的 主要目的是：(1)通过监测肠道组织更新和再生的动态变化来描述肠道组织更新和再生的动力学。 BrdU标记的新生成骨细胞的分化；(2)寻找肠道差异表达基因 通过流式分选上皮细胞并进行基因表达微阵列分析；以及(3) 确定在新生细胞增殖和非自主过程中自主和非自主发挥作用的基因 在小规模、靶向的RNA干扰筛选下向肠上皮细胞分化。 与公共健康相关：成人干细胞通常会补充和修复消化道 在一生中。需要对这一现象有更深入的了解，才能有效地治疗消化系统疾病。 癌症和其他疾病。在这项提案中，参与这一过程的基因将在一个模型中进行识别 能够更新并完全再生其肠道的有机体。

PROJECT DESCRIPTION: Adult stem cells replenish cells lost due to normal attrition, and repair organs and tissues in response to injury. An excellent example of this phenomenon is the mammalian digestive epithelium, which completely renews its cells every 3-5 days under normal conditions, and can also replace cells lost to damage by radiation or cytotoxic substances (e.g. chemotherapy). This ability to rapidly self- renew is of great interest both because it predisposes the gastrointestinal system to cancer, and because the ability to promote renewal in specific disease contexts (e.g. short bowel syndrome) would be clinically beneficial. Additionally, an understanding of gastrointestinal repair may advance the more general application of stem cell technology to regenerative medicine. Despite recent progress, however, the molecular mechanisms regulating gastrointestinal stem cell maintenance, proliferation, and differentiation are not well understood. Because of their remarkable regenerative abilities and numerous recent advances in the application of modern molecular techniques, planariansare an attractive model organism for investigating tissue renewal and stem cell biology. In planarians, adult stem cells called neoblasts replenish tissues during normal cell turnover and during regeneration after injury. As one of the most prominent organs in the animal, the intestine of planarians offers an excellent opportunity to approach the molecular mechanisms linking injury and cell turnover to stem cell proliferation and lineage restriction. The experiments proposed capitalize on established techniques to identify genes expressed by planarian intestinal epithelial cells required for intestinal renewal and regeneration. The specific aims of this proposal are (1) to characterize the dynamics of tissue renewal and regeneration in the intestine by monitoring the differentiation of BrdU-labeled neoblasts; (2) to identify genes that are differentially expressed by intestinal epithelial cells by flow sorting these cells and conducting microarray analysis of gene expression; and (3) to identify genes that function autonomously and non-autonomously during neoblast proliferation and differentiation into intestinal epithelial cells in a small-scale, targeted RNA interference screen. PUBLIC HEALTH RELEVANCE: Adult stem cells normally replenish and repair the digestive tract throughout life. Deeper understanding of this phenomenon is required for effective treatment of digestive cancers and other diseases. In this proposal genes involved in this process will be identified in a model organism that can renew and completely regenerate its intestine.