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: 8579382
• 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 2018-07-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8579382
• 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; 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; public health relevance; 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(SCs)朝向特定的细胞命运进行替代治疗，我们需要了解SCs是如何被调控增殖并分化为其后代谱系的。这些SC的命运决定被认为是由其直接微环境或利基中的特定细胞发出的信号协调的。毛囊形态发生是通过生态位信号调控干细胞的一个很好的模型系统，因为发育步骤和时间都是明确的。然而，与大多数其他器官中的干细胞壁龛一样，由于长期以来缺乏分离、表征和靶向干细胞壁龛细胞的遗传工具，调节皮肤SC命运的特定壁龛信号在很大程度上是未知的。 特化的毛乳头(DP)前体细胞被认为是作为壁龛细胞与早期毛发胎盘中的干细胞相互作用形成HFs。然而，到目前为止，还没有直接的证据表明DP前体是形成HF所必需的，我们也不知道难以捉摸的命运指定信号的性质，这主要是因为缺乏现代遗传方法来靶向这些细胞进行分离和基因/细胞消融。在我们正在进行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形成的最早阶段进行基因/细胞消融。在这项建议中，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。我们将利用我们新建立的由TBX18驱动的可诱导Cre系作为第一个用于DP前体细胞毒性细胞消融的遗传驱动因素，并确定它们对HF形成的绝对需求。相反，我们将从TBX18和Sox2驱动的GFP系中分离DP前体细胞，并在毛发诱导试验中直接确定这些细胞与非特化的成纤维细胞相比是否足以诱导HF的形成。然后，我们将使用可诱导的Cre介导的单个DP前体细胞的命运图谱来确定它们与成熟DPS和真皮鞘的谱系关系，并调查DPS中潜在的等级和异质性。我们将通过去除连环蛋白基因进一步确定Wnt信号在胚胎生态位中的具体作用。我们最终将系统地鉴定新的DP生态位信号，并通过缺失DP前体基因从功能上研究它们在体内的作用。这项工作将确定胚胎DP生态位及其信号(S)中的必要基因，这些基因在HF形成过程中激活SCs。这些研究的应用在于它们有可能改善再生疗法，旨在为烧伤患者或患有衰弱皮肤病的患者恢复完全功能的皮肤，包括HFs，由于我们对基本支持利基信号的了解有限，目前缺乏这项技术。这些发现也将对其他器官系统的再生疗法具有全球相关性，在其他器官系统中，干细胞的利基环境可以维持组织的动态平衡。