Characterization of regulators of hemotopoietic stem cell homeostasis

描述(由申请人提供)： 造血干细胞(HSCs)产生了成年脊椎动物中发现的每一种确定的血统。在胚胎发育过程中，Runx1是确定HSC规格所必需的，并调节成人HSC的动态平衡。我最近在斑马鱼中对RUNX1 HSC形成的修饰物进行了化学遗传筛选，并确定前列腺素途径是HSC的一个保守的脊椎动物调节因子。一种稳定的前列腺素E2(PGE2)衍生物被发现是斑马鱼和小鼠HSCs的有效诱导剂，目前正在开发用于移植前HSCs体外扩增的人类临床试验。为了进一步确定脊椎动物胚胎中HSC诱导的控制机制，我计划在AGM中研究WNT和前列腺素途径在HSC形成中的相互作用。我假设前列腺素途径调节WNT介导的胚胎和成人HSC的诱导。为了表征WNT通路在HSC形成中的作用，我将使用几个热休克诱导的转基因斑马鱼品系，它们表达WNT信号的激活物或抑制物。通过化学操作和吗啉寡核苷酸(MO)抑制PGE2的产生，我将测试前列腺素信号如何促进或抑制WNT介导的HSC的形成，并确定这种相互作用在成人骨髓和人脐血HSC动态平衡中的保守性。综上所述，这些研究将加深我们对HSC形成和动态平衡调节机制的理解。刺激这些通路可能有助于治疗血液病、骨髓衰竭或移植后的恢复，而抑制通路可能有助于白血病的治疗。K01奖将帮助我实现成为一名独立科学家的目标，在学术环境中研究HSC诱导和功能的调节。 与公共健康相关：造血干细胞构成了我们血液和免疫系统的基础；这些细胞的形成和功能在体内受到仔细的控制。这项拟议的研究将有助于确定调控这些干细胞的诞生和繁殖的机制。这项工作对于开发新的调节白血病的药物，以及从化疗和骨髓移植中恢复具有重要意义。

DESCRIPTION (provided by applicant): Hematopoietic stem cells (HSCs) give rise to each of the definitive blood lineages found in the adult vertebrate. Runxl is required for definitive HSC specification during embryogenesis and regulates adult HSC homeostasis. I recently performed a chemical genetic screen for modifiers of runx1+ HSC formation in zebrafish and identified the prostaglandin pathway as a conserved vertebrate regulator of HSCs. A stable prostaglandin E2 (PGE2) derivative was found to be a potent inducer of both zebrafish and murine HSCs and is currently being developed for use in human clinical trials for ex vivo expansion of HSCs prior to transplantation. To further characterize mechanisms controlling HSC induction in the vertebrate embryo, I plan to examine the interaction of the wnt and prostaglandin pathways in HSC formation in the AGM. I hypothesize that the prostaglandin pathway regulates wnt mediated induction of HSCs in the embryo and in adult HSC homeostasis. To characterize the role of the wnt pathway in HSC formation, I will use several heatshock inducible transgenic zebrafish lines that express activators or repressers of wnt signaling. Through chemical manipulation as well as morpholino oligonucleotide (MO) knock-down of PGE2production, I will test how prostaglandin signaling can enhance or suppress wnt mediated HSC formation and determine the conservation of this interaction in adult marrow and human cord blood HSC homeostasis. Taken together, these studies will enhance our understanding of the mechanisms regulating HSC formation and homeostasis. Stimulation of these pathways may prove beneficial for the treatment of patients with hematological disorders, bone marrow failure or in recovery after transplantation, while pathway inhibition might be useful in the treatment of leukemia. A K01 award will aid me in achieving my goal of becoming an independent scientist in an academic setting studying the regulation of HSC induction and function. PUBLIC HEALTH RELEVANCE: Hematopoietic stem cells form the foundation of our blood and immune system; the formation and function of these cells are carefully controlled in the body. The proposed research will help to identify mechanisms that regulate the birth and propagation of these stem cells. This work has great relevance for the development of novel agents to regulate leukemia, and for recovery from chemotherapy and bone marrow transplant.