Molecular Mechanisms of Cell Fate Decisions in Hair Follicle Stem Cells

描述（由申请人提供）：解读成体干细胞（SC）命运决定的分子机制对于理解疾病和组织再生治疗至关重要。这项建议的总体目标是利用毛囊和皮肤作为模型系统，在分子水平上解决转录因子和表观遗传调节在命运选择中的相互作用 脊椎动物成体干细胞群体在其天然组织中的决定。因为头发 毛囊干细胞在小鼠皮肤中同步增殖并恢复静止， 该系统允许以其他方式更难以实现的机械洞察。在aim中 (1)我们计划更深入地调查更多的休眠与 毛囊干细胞龛中更活跃的细胞亚群，通过表征其 在细胞培养和细胞移植测定中的形态发生和自我更新能力。 干细胞龛中这两种细胞亚群的存在似乎是 这是至少几种脊椎动物组织的相对共同的特征。他们的相互作用， 维持组织内稳态对于准确描述干细胞是重要的 行为和命运的决定。在目标（2）中，我们将检查组蛋白标记的分布 通过染色质免疫沉淀在干细胞活性的两个阶段跨越基因组 并试图检查两个已知的成人组织之间的潜在联系 干细胞特征：静止性和可塑性。在目标（3）中，我们将使用两个 转录因子Runx1和Gata6作为命运获得调节因子。我们将测试他们的 在通过与干细胞的相互作用重塑组蛋白表观基因组的潜在意义 一组蛋白修饰酶，我们发现表达在毛囊中， 相关模式我们将诱导小鼠皮肤中Runx1和Gata6的急性丢失， 检测特定组蛋白修饰酶的mRNA表达水平， 相关的毛囊细胞群。此外，我们将进行免疫共沉淀 或下拉实验来检查潜在的直接蛋白质-蛋白质相互作用 Runx1或Gata6与特定组蛋白修饰酶之间的关系。这将开始 阐明脊椎动物成体干细胞群体中命运获得的机制 并揭示了转录因子之间的相互作用， 在协调细胞命运和组蛋白表观遗传标记的全球重塑中的调节剂。

DESCRIPTION (provided by applicant): Deciphering the molecular mechanisms of adult stem cell (SC) fate decisions is essential for understanding disease and for tissue regenerative therapy. The overall goal of this proposal is to utilize hair follicles and skin as model systems to address at the molecular level the interplay of transcriptional factors and epigenetic regulation in fate choice decisions of a vertebrate adult stem cell population in its native tissue. Because hair follicle stem cells synchronously proliferate and return to quiescence in the mouse skin, this system allows mechanistic insight that is otherwise more difficult to achieve. In Aim (1) we plan to investigate in more depth the relationship between more dormant versus more active cell subpopulations in the hair follicle stem cell niche, by characterizing their morphogenetic and self-renewal ability in cell culture and cell transplantation assays. The existence of these two kinds of cell subpopulations in stem cell niches appears to be a relatively common feature for at least several vertebrate tissues. Their interplay in maintaining tissue homeostasis is important for accurate description of stem cell behavior and fate decisions. In Aim (2) we will examine the distribution of histone marks across the genome at two stages of stem cell activity by chromatin immuno-precipitation and sequencing, and attempt to examine a potential link between two known adult tissue stem cells features: quiescence and plasticity. In Aim (3) we will employ two transcription factors Runx1 and Gata6 as fate acquisition regulators. We will test their potential implication in remodeling the stem cell histone epigenome via interactions with a battery of histone modifying enzymes we found expressed in the hair follicle in a relevant pattern. We will induce acute loss of Runx1 and Gata6 in mouse skin and examine the mRNA expression level of specific histone modifying enzymes in the relevant hair follicle cell populations. In addition we will perform co-immunoprecipitation or pull-down experiments to examine a potential direct protein-protein interaction between Runx1 or Gata6 and specific histone modifying enzymes. This will begin to address the mechanisms of fate acquisition in a vertebrate adult stem cell population and shed light on the interplay between transcription factors that work as master regulator in orchestrating cell fate and global remodeling of histone epigenetic marks.