Specific ion flows: a novel signal mediating stem cell-niche communication

描述（由申请人提供）：损伤后的模式再生和正常细胞更新期间的形式维持需要成体干细胞的参与。为了理解并最终学会控制这些生物医学应用的过程，有必要确定干细胞与其邻居通信的分子机制。干细胞需要这样的交流来知道在哪里，何时以及如何分化。由于基本的细胞控制机制是广泛保守的，因为我们相信，可以在系统中取得根本性的进展，是服从于可识别的成人干细胞群体的分子研究，我们建议研究干细胞的相互作用，在体内利用一个强大的模型系统：Planarian Schmidtea mediterranea。这些复杂的扁形虫能够使用可识别的成体干细胞群来替换它们身体的任何部分：新生细胞。这是一个理想的系统，在其中研究的分子信号发送到和从neoblast。在对比和补充该领域的重点生化因素，我们的实验室研究内源性离子流，pH值和电压梯度在控制细胞增殖，迁移和分化的作用。我们将测试的假设，控制干细胞的行为在其环境中的本地和远程信号的大部分是生物电，由特定的离子通道和泵活动的生理结果。我们将描述几个通道，泵和间隙连接在控制干细胞位置信息和再生过程中的贡献的参与。我们提出两个主要目标：1）分子验证（使用RNAi）的几个候选通道和泵蛋白参与新成纤维细胞介导的事件，其次是他们的表达分析和他们的角色在再生和重塑的详细表征;和2）表征干细胞在分化的不同阶段进展时的生物电特性和控制新生细胞运动，增殖，和体内分化。我们小组在几种脊椎动物和无脊椎动物系统中的胚胎发育和再生领域开发的专业知识将允许快速和重要的进展，以揭示干细胞调控的新方面，并将导致一套全新的干细胞信号控制的高回报结果，其最终将用于驱动旨在诱导患者的成体细胞再生的生物医学应用。这项工作非常适合癌症，衰老，生物医学成像和生物工程研究所，因为我们建议使用新的成像和生物物理操作技术来实现医学应用，其中成人干细胞可以被诱导以适当地替代老化，受损或癌变组织。我们的工作将有助于理解成体干细胞如何让一些动物完美地修复其身体的任何部分。这些信息将用于开发方法，从而可以在人类患者受伤，衰老或肿瘤生长后诱导组织，器官和附属物的再生。

DESCRIPTION (provided by applicant): The regeneration of pattern following injury and the maintenance of form during normal cellular turnover requires the participation of adult stem cells. In order to understand and ultimately learn to control these processes for biomedical applications, it is necessary to identify the molecular mechanisms by which stem cells communicate with their neighbors. Such communication is needed for stem cells to know where, when, and how to differentiate. Because fundamental cellular control mechanisms are widely conserved, and because we believe fundamental progress can be made in systems that are amenable to the molecular investigation of a recognizable adult stem population, we propose study stem cell interactions in vivo by capitalizing on a powerful model system: the planarian Schmidtea mediterranea. These complex flatworms are able to replace any part of their body using a recognizable adult stem cell population: the neoblasts. This is an ideal system in which to investigate the molecular signals sent to and from neoblasts. In contrast and complement to the field's focus on biochemical factors, our lab studies roles of endogenous ion flows, and pH and voltage gradients in controlling cell proliferation, migration, and differentiation. We will test the hypothesis that a large component of the local and long-range signals controlling stem cell behavior within their environment is bioelectrical, consisting of the physiological results of specific ion channel and pump activity. We will characterize the involvement of several channels, pumps, and gap junctions in controlling stem cell positional information and their contribution during regeneration. We propose two main aims: 1) molecular validation (using RNAi) of several candidate channel and pump proteins involved in neoblast-mediated events, followed by their expression analysis and a detailed characterization of their roles in regeneration and remodeling; and 2) characterization of the bioelectrical properties of stem cells as they progress through the different phases of differentiation and development of functional techniques to control neoblast movement, proliferation, and differentiation in vivo. The expertise which our group has developed with this field in embryonic development and regeneration in several vertebrate and invertebrate systems will allow rapid and important progress to uncover novel aspects of stem cell regulation, and will result in the high-reward outcome of an entirely new set of controls of stem cell signaling, which ultimately will be used to drive biomedical applications aiming to induce regeneration in adult cells of the patient. This work is an ideal fit for the Cancer, Aging, and Biomedical Imaging and Bioengineering Institutes because we propose to use novel imaging and biophysical manipulation techniques to enable medical applications in which adult stem cells can be induced to properly replace aging, damaged, or cancerous tissue. Our work will lead to the understanding of how adult stem cells allow some animals to perfectly repair any part of their body. This information will be used to develop methods whereby regeneration of tissues, organs, and appendages may be induced in human patients following injury, aging, or tumor growth.