Exploring How Dermal Papilla Precursors Regulate Hair Follicle Formation

探索真皮乳头前体如何调节毛囊形成

• 批准号: 8877403
• 负责人: Michael Rendl
• 金额: $ 35.91万
• 依托单位: ICAHN SCHOOL OF MEDICINE AT MOUNT SINAI
• 依托单位国家: 美国
• 财政年份: 2013
• 资助国家: 美国
• 起止时间: 2013-08-01 至 2016-07-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8877403
• 关键词: Ablation; Address; Biological Assay; Biological Models; Burn injury; Cell Separation; Cells; Data; Dermal; Dermatology; Dermis; Development; Embryo; Embryonic Development; Essential Genes; Fibroblasts; Future; Gene Deletion; Gene Targeting; Genes; Genetic; Goals; Hair; Hair follicle structure; Health; Heterogeneity; Homeostasis; Individual; Journals; Knock-out; Label; Maps; Mediating; Methods; Molecular; Molecular Profiling; Morphogenesis; Natural Killer Cells; Nature; Organ; Patients; Play; Population; Process; Proliferating; Publishing; Regulation; Replacement Therapy; Role; Signal Pathway; Signal Transduction; Skin; Skin Tissue; Specific qualifier value; Stem cells; System; Technology; Testing; Time; Tissues; Work; body system; chemokine receptor; improved; in vivo; novel; precursor cell; regenerative; regenerative therapy; self-renewal; skin disorder; stem cell fate; stem cell niche; tongue papilla; tool; transcription factor

DESCRIPTION (provided by applicant): To coax tissue stem cells (SCs) towards specific cell fates for replacement therapies, we need to understand how SCs are regulated to proliferate and differentiate into their progeny lineages. These SC fate decisions are thought to be coordinated by signals from specialized cells in their immediate microenvironment, or niche. Hair follicle (HF) morphogenesis is an excellent model system for SC regulation by niche signals, since the developmental steps and timing are well-defined. However, as with SC niches in most other organs, the specific niche signals that regulate skin SC fates are largely unknown, due to the long-standing lack of genetic tools to isolate, characterize and target the niche cells. Specialized dermal papilla (DP) precursor cells are thought to interact as niche cells with SCs in incipient hair placodes to form HFs. To date, however, no direct proof exists that DP precursors are required for HF formation nor do we know the nature of the elusive fate-specifying signals, largely due to the lack of modern genetic methods for targeting these cells for isolation and gene/cell ablation. In our ongoing effort and new preliminary data, we have developed much-needed genetic strategies to isolate, characterize and target embryonic DP niche cells for gene/cell ablation during the earliest steps of HF formation. In this proposal, we will utilize genetic drivers of DP genes Tbx18 and Sox2 to test the hypothesis that DP cells establish a niche for HF stem cells. We will utilize our newly established Tbx18-driven inducible Cre line as the first genetic driver for cytotoxic cell ablation of DP precursors and determine their absolute requirement for HF formation. Conversely, we will isolate DP precursors from Tbx18- and Sox2-driven GFP lines and directly determine in hair induction assays whether these cells are sufficient to induce HF formation in comparison to unspecialized fibroblasts. We will then employ inducible Cre-mediated single-cell fate mapping of individual DP precursor cells to define their lineage relationships with mature DPs and dermal sheaths and to investigate the potential hierarchy and heterogeneity within DPs. We will further determine the specific role of Wnt signaling in the embryonic niche by �-catenin gene ablation. We will finally systematically identify novel DP niche signals and functionally investigate their role in vivo by DP precursor-specific gene deletion. This work will identify essential genes in the embryonic DP niche and its signal(s) that activate SCs during HF formation. The application of these studies lies in their potential to improve regenerative therapies meant to restore fully functional skin including HFs for burn victims or patients with debilitating skin diseases, a technology which currently is lacking due to our limited understanding of essential supporting niche signals. These findings will also have global relevance for regenerative therapies in other organ systems, where SC niches operate to maintain tissue homeostasis.

描述（由申请人提供）：为了诱导组织干细胞（SC）走向替代疗法的特定细胞命运，我们需要了解如何调节 SC 增殖并分化为其后代谱系。这些 SC 命运决定被认为是由来自其直接微环境或生态位中的特殊细胞的信号协调的。毛囊 (HF) 形态发生是通过生态位信号进行 SC 调节的优秀模型系统，因为发育步骤和时间是明确定义的。然而，与大多数其他器官中的 SC 生态位一样，由于长期缺乏分离、表征和靶向生态位细胞的遗传工具，调节皮肤 SC 命运的特定生态位信号在很大程度上是未知的。 特化的真皮乳头 (DP) 前体细胞被认为作为生态位细胞与初期毛基板中的 SC 相互作用，形成 HF。然而，迄今为止，没有直接证据表明 DP 前体是 HF 形成所必需的，我们也不知道难以捉摸的命运指定信号的性质，这主要是由于缺乏针对这些细胞进行分离和基因/细胞消融的现代遗传方法。在我们持续的努力和新的初步数据中，我们开发了急需的遗传策略来分离、表征和靶向胚胎 DP 利基细胞，以便在 HF 形成的最早步骤中进行基因/细胞消融。在本提案中，我们将利用 DP 基因 Tbx18 和 Sox2 的遗传驱动因素来检验 DP 细胞为 HF 干细胞建立利基的假设。我们将利用新建立的 Tbx18 驱动的诱导型 Cre 系作为 DP 前体细胞毒性细胞消融的第一个遗传驱动因素，并确定它们对 HF 形成的绝对要求。相反，我们将从 Tbx18 和 Sox2 驱动的 GFP 系中分离 DP 前体，并在毛发诱导测定中直接确定与非特化成纤维细胞相比，这些细胞是否足以诱导 HF 形成。然后，我们将利用单个 DP 前体细胞的诱导型 Cre 介导的单细胞命运图谱来定义它们与成熟 DP 和真皮鞘的谱系关系，并研究 DP 内潜在的层次结构和异质性。我们将通过β-catenin基因消融进一步确定Wnt信号在胚胎生态位中的具体作用。我们最终将系统地识别新的 DP 生态位信号，并通过 DP 前体特异性基因删除来功能性研究它们在体内的作用。这项工作将鉴定胚胎 DP 生态位中的必需基因及其在 HF 形成过程中激活 SC 的信号。这些研究的应用在于其改善再生疗法的潜力，这些再生疗法旨在恢复烧伤患者或患有衰弱性皮肤病患者的皮肤的功能完整，包括高频疗法，由于我们对基本支持生态位信号的了解有限，目前缺乏这项技术。这些发现对于其他器官系统的再生疗法也具有全球意义，在这些器官系统中，SC 生态位发挥着维持组织稳态的作用。