Mechanisms of Organ Regeneration in the planarian Schmidtea mediterranea

描述（由申请人提供）：所有动物在其一生中都会经历毒素，病原体和身体创伤的组织损伤。受损组织的修复和更新是必不可少的，但我们对这一过程在分子水平上知之甚少，了解它对再生医学的发展至关重要。一种常见的组织修复机制依赖于干细胞的激活来产生损伤期间丢失的新组织。我将研究地中海施米德涡虫（Schmidtea mediterranea）干细胞驱动器官再生的控制机制，地中海施米德涡虫是一种具有非凡再生能力和高度可获得干细胞群的动物。我将重点关注咽部，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结合和细胞周期分析来定义对截肢和再生的细胞反应。对正在进行咽再生的动物进行微阵列分析，将确定在这一过程中受到差异调节的基因。为了发现咽再生所需的其他基因，我将在咽截肢的同时对涡虫cdna进行大规模RNA干扰（RNAi）筛选。rnai喂养动物的形态、功能和解剖表型将确定假定的候选基因。对于候选再生基因，我将确定再生过程中的表达模式，并表征由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会特异性地识别咽的缺失。总之，这些实验将确定参与成年动物新器官组装的分子途径。本提案的研究探讨了成年动物的干细胞在切除整个器官后如何能够再生。实验集中在涡虫身上，涡虫是一种可以再生所有器官并拥有非常容易获得的干细胞的动物。由于干细胞在人体损伤过程中经常被激活，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.