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

项目描述：成体干细胞补充由于正常损耗而丢失的细胞，并修复器官 和组织对损伤的反应。这种现象的一个很好的例子是哺乳动物的消化系统 上皮细胞，在正常情况下每3-5天完全更新其细胞，也可以取代 细胞因辐射或细胞毒性物质（如化疗）损伤而丢失。这种快速自我调节的能力 更新是非常感兴趣的，因为它使胃肠道系统容易患癌症， 在特定疾病情况下（例如短肠综合征）促进更新的能力在临床上是 有利于此外，对胃肠道修复的理解可能会促进更普遍的 干细胞技术在再生医学中的应用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 并没有得到很好的理解。 由于其显著的再生能力和许多最近的进展， 利用现代分子生物学技术，Planarians是研究组织更新的一个有吸引力的模式生物 和干细胞生物学在真涡虫中，称为新母细胞的成体干细胞在正常细胞分化期间补充组织。 损伤后的周转和再生过程中。作为动物中最重要的器官之一， 肠道的涡虫提供了一个很好的机会，探讨分子机制连接损伤 以及细胞周转到干细胞增殖和谱系限制。 提出的实验利用现有的技术来鉴定真涡虫表达的基因， 肠上皮细胞需要肠更新和再生。本提案的具体目标 是（1）通过监测肠中的组织更新和再生的动力学来表征肠中的组织更新和再生的动力学。 BrdU标记的新成纤维细胞的分化;（2）鉴定肠上皮细胞差异表达的基因， 上皮细胞，通过流式分选这些细胞并进行基因表达的微阵列分析;和（3） 鉴定在新生细胞增殖期间自主和非自主发挥功能的基因， 在小规模的靶向RNA干扰筛选中， 公共卫生相关性：成人干细胞通常补充和修复消化道 在生活中。为了有效地治疗消化道疾病，需要对这种现象有更深入的了解。 癌症和其他疾病。在这个提议中，参与这一过程的基因将在一个模型中被识别出来。 能够更新和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.