Restoring hair follicle stem cell fate and heterogeneity outside their native niche

项目摘要 成体干细胞（SC）存在于特定的小生境中，并依赖于微环境线索来指导它们的行为。 毛囊（HF）是一个很好的模型系统，以研究丰富的SC-生态位相互作用，因为它经历 刻板的再生周期这个独立的微型器官利用高水平的空间组织， 区室化以促进SC沿着沿着HF谱系的命运决定。然而，当毛囊干 细胞（HFSC）从它们的小生境中分离出来，它们失去了它们的身份，并显示出广泛的可塑性， 可以产生皮肤的所有谱系。这种多能状态长期以来一直是恢复HFSC身份的障碍 尽管有大量关于控制HFSC的信号的信息， 行为为了克服这一挑战，我建立了我们实验室最近的发现，即培养的HFSC表现出 一种伤口样的表观遗传特征，并假设靶向负责驱动 伤口反应将允许HFSC身份的重新获得。在这里，我在这里介绍的发展， 通过我对生态位的识别， 这些信号位于组织再生和创伤相关可塑性之间的交叉点。我的初步数据 证明了靶向这些途径以解决伤口特征并恢复其敏感性的功效 支持获得全套分化的HF细胞类型的局部线索。在这份提案中，我将 使用单细胞检测HFSC命运响应于优化的小生境信号的异质性 转录组学我不断发展的生物信息学技能将使我能够将这些细胞的命运与它们在体内的命运进行比较， （目标一）。接下来，我将剖析维甲酸（RA），一种必需的代谢产物所起的作用机制 这是HFSC身份和自我更新所必需的。通过关注RA的转录效应子，我将在功能上 定义RA可用性如何影响HF循环和伤口诱导的卵泡新生（Aim II）。最后，我将 将该平台应用于人类患者样本，并从功能上剖析HFSC与其真皮生态位的相互作用 在新的工程皮肤（目标III）。总之，这项工作将机械地确定最低要求 人HFSC自我更新和分化所必需的。如果成功，我的研究有可能 快速建模和测试与人类HF疾病相关的假设，加速旨在 实现HF形态发生，并最终再生完整的表皮系统。

PROJECT SUMMARY Adult stem cells (SCs) reside in defined niches and depend on microenvironmental cues to instruct their behavior. The hair follicle (HF) is an excellent model system to study a rich set of SC-niche interactions as it undergoes stereotypic regenerative cycles. This self-contained mini-organ utilizes high levels of spatial organization and compartmentalization to promote SC fate determination along HF lineages. However, when hair follicle stem cells (HFSCs) become isolated from their niche, they lose their identity and display a wide-ranging plasticity that can produce all lineages of the skin. This multipotent state has long acted as a barrier to restoring HFSC identity when the niche becomes disrupted, despite a wealth of information regarding the signals that control HFSC behavior. To overcome this challenge, I have built upon our lab’s recent discovery that cultured HFSCs exhibit a wound-like epigenetic signature and hypothesized that targeting the pathways responsible for driving the wound response would permit the re-acquisition of HFSC identity. Here, I present here the development of a platform that reinstates the homeostatic identify of HFSCs, made possible through my identification of niche signals that lie at the intersection between tissue regeneration and wound-related plasticity. My preliminary data demonstrate the efficacy of targeting these pathways to resolve the wound signature and restore their sensitivity to local cues that support the acquisition of a full suite of differentiated HF cell types. In this proposal, I will examine the resulting heterogeneity of HFSC fates in response to optimized niche signals using single cell transcriptomics. My developing bioinformatic skillset will allow me to compare these cell fates with their in vivo counterparts (Aim I). Next, I will dissect the mechanistic role played by retinoic acid (RA), an essential metabolite required for HFSC identity and self-renewal. By focusing on the transcriptional effectors of RA, I will functionally define how RA availability impacts HF cycling and wound-induced follicular neogenesis (Aim II). Lastly, I will apply this platform to human patient samples and functionally dissect HFSC interactions with their dermal niche in newly engineered skin (Aim III). In total, this work will mechanistically define the minimal requirements necessary for human HFSC self-renewal and differentiation. If successful, my research has the potential to rapidly model and test hypotheses related to human HF disorders, accelerate therapeutic efforts aimed at achieving HF morphogenesis, and ultimately regenerate the complete integumentary system.