Mechanisms of Organ Regeneration in the planarian Schmidtea mediterranea

描述（由申请方提供）：所有动物在其一生中都经历毒素、病原体和身体创伤造成的组织损伤。受损组织的修复和更新是必不可少的，但我们在分子水平上对这一过程知之甚少，了解它对于再生医学的发展至关重要。组织修复的一种常见机制依赖于干细胞的活化以产生在损伤期间丢失的新组织。我将调查的机制，控制干细胞驱动的器官再生的涡虫Schmidtea mediterranea，一种动物具有显着的再生能力和高度可访问的干细胞群体。我会专注于咽部，它可以被选择性地切除，并在十天内完全再生。我的第一个目标是使用BrdU掺入和细胞周期分析来确定截肢和再生的细胞反应。微阵列分析的动物咽再生将确定在这一过程中差异调节的基因。为了发现咽再生所需的其他基因，我将结合大规模RNA干扰（RNAi）筛选真涡虫cDNA和咽切除。RNAi喂养的动物的形态学、功能和解剖学表型将鉴定推定的候选基因。对于候选再生基因，我将确定在再生过程中的表达模式，并表征基因敲低引起的解剖和细胞表型。我还将确定候选基因是否特异性地识别咽部的缺失。总之，这些实验将确定成年动物中新器官组装所涉及的分子途径。相关性这项提案中的研究探讨了成年动物中的干细胞如何能够在切除后再生整个器官。实验的重点是Planarians，这种动物可以再生每个器官，并且具有非常容易获得的干细胞。由于干细胞在人类受伤期间经常被激活，这些研究将有助于我们对再生医学和干细胞生物学的理解。

DESCRIPTION (provided by applicant): All animals experience tissue injury from toxins, pathogens and bodily trauma throughout their lives. Repair and renewal of damaged tissues is essential, but we know little about this process at the molecular level, and understanding it is critical for the development of regenerative medicine. One common mechanism of tissue repair relies upon activation of stem cells to produce new tissue lost during injury. I will investigate the mechanisms controlling stem-cell-driven organ regeneration in the planarian Schmidtea mediterranea, an animal with a remarkable capacity for regrowth and a highly accessible stem cell population. I will focus on the pharynx, which can be selectively amputated and completely regenerates within ten days. My first goal is to define the cellular response to amputation and regeneration using BrdU incorporation and cell cycle analysis. Microarray analysis of animals undergoing pharynx regeneration will identify genes that are differentially regulated during this process. To uncover additional genes required for pharynx regeneration, I will couple a large-scale RNA interference (RNAi) screen of planarian cDNAs with pharynx amputation. Morphological, functional and anatomical phenotypes of RNAi-fed animals will identify putative candidate genes. For candidate regeneration genes, I will determine expression patterns during regeneration and characterize the anatomical and cellular phenotypes caused by gene knockdown. I will also determine whether candidate genes act specifically to recognize the absence of a pharynx. Together, these experiments will identify the molecular pathways involved in the assembly of new organs in adult animals. Relevance The research in this proposal explores how stem cells in adult animals are able to regenerate an entire organ after its removal. The experiments focus on planarians, animals that can regenerate every organ and have extremely accessible stem cells. Because stem cells are often activated during human injuries, these studies will contribute to our understanding of regenerative medicine and stem cell biology.