A Promitotic Stem Cell Niche: Role For Beta-Catenin and TGFbeta

描述(申请人提供)：概述：这项建议的目标是确定调节气管、支气管壁上皮组织特异性干细胞(TSC)与其生态位之间相互作用的细胞和分子机制。对于许多上呼吸道疾病，如COPD、哮喘和CF，已经提出了TSC自我更新和分化程序的失调。 我的初步数据表明，小鼠气管TSCs产生了它们自己的生态位，在本质上是有丝分裂的，对这个生态位的修改是分化所必需的。这种修饰是通过来自分化的气管细胞的环境线索来完成的。基于这些初步数据，我将确定1)这些TSCs在组织修复中的作用，以及2)参与维持增殖利基的信号通路。 这项研究的意义：这项研究将通过两个基本范式推动肺TSC领域的发展：1)TSC参与受损上皮的修复，2)允许运输放大细胞(TAC)分化的信号通路。最后，这项研究对基于细胞的治疗的“种子和土壤”范式进行了重要的修改，提出了将纯干细胞/利基细胞引入受损器官可能导致有丝分裂队列不受限制地扩大的可能性，这是由于与疾病相关的、修改利基的分化细胞的耗尽。 创新：发展一种边缘克隆分析方法，可以从单个TSC产生大量TAC(8x10^3)。这种方法将通过细胞混合研究和药理学方法，使用转基因小鼠的TSC来分析信号机制。因此，我将第一次有能力在受控条件下评估TSC的增殖和分化。

DESCRIPTION (provided by applicant): Overview: The goal of this proposal is to identify the cellular and molecular mechanisms that regulate interactions between the tracheobronchial epithelial tissue-specific stem cell (TSC) and its niche. Dysregulation of the TSC self-renewal and differentiation program has been suggested for many upper airway diseases like COPD, asthma, and CF. My preliminary data indicate that mouse tracheal TSCs generate their own niche that is promitotic in nature and modification of this niche is necessary for differentiation. This modification is accomplished by environmental cues derived from differentiated tracheal cells. Based on this preliminary data, I will determine 1) the role of these TSCs in tissue repair, and 2) the signaling pathways involved in maintenance of the proliferative niche. Significance of the study: This study will advance the field of lung TSC by addressing 2 fundamental paradigms: 1) TSC participation in repair of the damaged epithelium, and 2) signaling pathways that allow differentiation of transit amplifying cells (TAC). Finally, this study provides an important modification of the "seed and soil" paradigm for cell-based therapy by raising the possibility that introduction of pure stem/niche cells to an injured organ may result in unrestrained expansion of the mitotic cohort due to disease-associated depletion of the differentiated cells that modify the niche. Innovation: Development of a rim-clone assay allows generation of large number of TAC (8x10^3) from a single TSC. This method will permit analysis of signaling mechanisms using TSC from genetically-modified mice, through cell-mixing studies and using pharmacological approaches. Thus, I will have the ability to evaluate TSC proliferation and differentiation under controlled conditions for the first time.