Characterization of regulators of hemotopoietic stem cell homeostasis

描述（由申请人提供）： 造血干细胞（HSC）产生在成年脊椎动物中发现的每种确定的血液谱系。Runxl是胚胎发生期间确定性HSC特化所需的，并调节成体HSC稳态。我最近进行了一项化学遗传筛选，以寻找斑马鱼中runx 1 + HSC形成的修饰剂，并确定前列腺素途径是HSC的保守脊椎动物调节剂。研究发现，稳定的前列腺素E2（PGE 2）衍生物是斑马鱼和小鼠HSC的有效诱导剂，目前正在开发用于人类临床试验，用于移植前离体扩增HSC。为了进一步表征脊椎动物胚胎中HSC诱导的控制机制，我计划研究在AGM中HSC形成中wnt和前列腺素途径的相互作用。我推测前列腺素途径调节胚胎和成人HSC稳态中Wnt介导的HSC诱导。为了表征wnt途径在HSC形成中的作用，我将使用几种表达wnt信号传导激活剂或抑制剂的热休克诱导型转基因斑马鱼系。通过化学操作以及吗啉代寡核苷酸（MO）敲低PGE 2的生产，我将测试前列腺素信号如何可以增强或抑制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带血HSC稳态的保护。总之，这些研究将加强我们对HSC形成和稳态调节机制的理解。这些途径的刺激可能被证明有益于血液系统疾病、骨髓衰竭或移植后恢复的患者的治疗，而途径抑制可能在白血病的治疗中有用。一个K 01奖将帮助我实现我的目标，成为一个独立的科学家在学术环境中研究HSC诱导和功能的调节。 公共卫生相关性：造血干细胞是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精心控制。这项拟议中的研究将有助于确定调节这些干细胞出生和繁殖的机制。这项工作对于开发调节白血病的新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.