Toward Understanding the Role of the Polycomb Complex in Skin Control

了解 Polycomb 复合物在皮肤控制中的作用

• 批准号: 10229608
• 负责人: Elena Ezhkova
• 金额: $ 43.41万
• 依托单位: ICAHN SCHOOL OF MEDICINE AT MOUNT SINAI
• 依托单位国家: 美国
• 财政年份: 2016
• 资助国家: 美国
• 起止时间: 2016-02-01 至 2025-08-31
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/10229608
• 关键词: Ablation; Adult; Aging; Animals; Biochemical Genetics; Biological Process; ChIP-seq; Chromatin; Complex; Cues; Data; Disease; Down-Regulation; Equilibrium; Gene Activation; Gene Expression; Gene Expression Regulation; Genes; Genetic Transcription; Growth; Hair; Hair follicle structure; Homeostasis; Human; Knockout Mice; Lead; Life; Malignant Neoplasms; Mediating; Molecular; Multipotent Stem Cells; Mus; Mutate; Natural regeneration; Organism; PRC1 Protein; Periodicity; Phenotype; Play; Polycomb; Process; Production; Proliferating; Regulation; Regulator Genes; Reporting; Repression; Rest; Role; Signal Transduction; Skin; Skin Cancer; System; Testing; Transcription Coactivator; WNT Signaling Pathway; bone morphogenetic protein receptors; daughter cell; epithelial stem cell; experimental study; gene repression; human disease; in vivo; inhibitor/antagonist; insight; loss of function; multipotent cell; novel; premature; skin disorder; stem cells; transcriptome sequencing

Project Summary Hair follicle stem cells (HFSCs) have the unique ability to generate new hair follicles throughout the lifetime of an organism. When the growth of a new hair follicle occurs, HFSCs are activated; they proliferate to fuel the production of a new follicle and quickly return to quiescence. While the means by which this transition between quiescence and activation is regulated remain elusive, identification of these processes is critical, because abnormal HFSC activation has implications in hair loss, aging, and cancer. Polycomb repressive complexes (PRC) 1 and 2 are chromatin transcriptional regulators that are essential for maintaining stem cell identity. By performing loss-of-function studies, we showed that loss of PRC1 in HFSCs results in premature activation of HFSCs and the induction of hair growth, whereas loss of PRC2 leads to a prolonged HFSC quiescence and delayed hair growth. These data show the critical and opposing roles of Polycomb complexes in regulation of HFSC quiescence. This is an intriguing observation because PRC1 and PRC2 are thought to act together, and, in most systems, the loss of either PRC1 or PRC2 results in identical phenotypes. We hypothesize that PRC1 and PRC2 maintain the delicate balance of quiescence and activation, but their mechanism of action is different than what was previously reported. In Aim 1, we will determine the molecular mechanisms by which PRC2 fine-tunes HFSC quiescence. By performing RNA-seq, we identified that Wnt inhibitors Notum and Sfrp2, and BMP receptor Bmpr1b are upregulated in the PRC2-null HFSC. Because Wnt inhibition and Bmp activation are known to promote HFSC quiescence, we hypothesize that expression of these genes leads to delayed HFSC activation. Here, we will analyze whether expression of Notum, Sfrp2, and/or Bmpr1b promotes HFSC quiescence and recapitulates the PRC2-null phenotype. In Aim 2, we will examine cooperation between repressive PRC1 and PRC2 functions in control of HFSCs. Our recent studies showed that PRC1 and PRC2 have additive gene-repressive roles and that only loss of both leads to complete de-repression of PRC1/2 target genes. Here, we will ablate repressive functions of both PRC1 and PRC2 complexes in HFSCs, analyze the phenotype, and determine molecular mechanisms of PRC1/2 control of HFSCs. In Aim 3, we will examine noncanonical gene-activating roles of PRC1 in promoting HFSC quiescence. Because loss of PRC1 and PRC2 show opposing phenotypes, respectively, we hypothesize that PRC1 functions independently of PRC2 to promote the expression of genes that influence HFSC quiescence. Here, we will identify genes that are under the control of PRC1 in HFSCs by performing RNA-seq and ChIP-seq studies and test whether downregulation of said genes results in precocious HFSC activation. The completion of these studies will define how Polycomb-mediated gene regulation fine-tunes the delicate balance between quiescence and activation in HFSCs.

项目摘要 毛囊干细胞（HFSC）具有独特的能力，可以在整个生命周期中产生新的毛囊 有机体。当发生新毛囊的生长时，HFSC会激活；他们扩散以加油 产生新的卵泡，并迅速恢复静止。而这种过渡之间的方式 静止和激活的调节仍然难以捉摸，这些过程的识别至关重要，因为 异常HFSC激活对脱发，衰老和癌症具有影响。 Polycomb抑制性复合物（PRC）1和2是染色质转录调节剂，是必不可少的 用于维持干细胞身份。通过进行功能丧失研究，我们表明Prc1在 HFSC会导致HFSC的过早激活和诱导头发生长，而PRC2的损失则导致 长时间的HFSC静止和头发生长延迟。这些数据显示了 Polycomb复合物在HFSC静止的调节中。这是一个有趣的观察，因为PRC1和 人们认为PRC2可以一起起作用，在大多数系统中，PRC1或PRC2的丢失导致相同 表型。我们假设PRC1和PRC2保持静止和激活的微妙平衡， 但是它们的作用机理与以前报道的不同。 在AIM 1中，我们将确定PRC2微型HFSC静止的分子机制。经过 执行RNA-Seq，我们确定Wnt抑制剂Notum和SFRP2和BMP受体BMPR1B是 在PRC2-NULL HFSC中上调。因为已知WNT抑制和BMP激活可以促进HFSC 静止，我们假设这些基因的表达导致HFSC激活延迟。在这里，我们会的 分析Notum，SFRP2和/或BMPR1B的表达是否促进HFSC静止和概括 PRC2-NULL表型。在AIM 2中，我们将研究抑制性PRC1和PRC2之间的合作 控制HFSC的功能。我们最近的研究表明，PRC1和PRC2具有加性基因抑制 角色，只有两种损失才能完全消除PRC1/2靶基因的抑制。在这里，我们将消融 HFSC中PRC1和PRC2复合物的抑制作用，分析表型并确定 HFSC的PRC1/2控制的分子机制。在AIM 3中，我们将检查非规范基因激活 PRC1在促进HFSC静止中的作用。因为失去PRC1和PRC2表现出相反的表型，所以 我们分别假设PRC1独立于PRC2来促进基因的表达 这会影响HFSC静止。在这里，我们将确定由HFSC中PRC1控制下的基因 进行RNA-seq和ChIP-Seq研究并测试上述基因的下调是否导致 早熟的HFSC激活。这些研究的完成将定义多肉液介导的基因 调节HFSC中静止与激活之间的微妙平衡。