DNA Methylation Control Hematopoietic Stem Cell Lineage Differentiation

描述（由申请人提供）：候选人：我已经在贝勒医学院（休斯顿，德克萨斯州）的Margaret Goodell教授的实验室担任博士后研究员三年，来自博士学位。于2006年5月在昆士兰州大学（澳大利亚昆士兰州布里斯班）进行。我从澳大利亚NHMRC获得了最初的奖学金，以资助我博士后的前两年，在此期间，我研究了造血干细胞分化的分子调控和控制干细胞命运的表观遗传机制。我现在正在申请更多的高级奖学金，并开始采取初步措施，建立自己的研究计划。这次申请的时机代表了我职业生涯的一个十字路口，我开始向独立过渡，并开始自己的研究计划。 我在理解造血干细胞的分子调控方面的工作是出于改善造血疾病患者生活的愿望，我的最终职业目标是看到HSC生物学中有意义的发现的实施，以帮助推动新的临床结果。我相信，本提案中概述的工作最终可能为广泛的患者带来新的治疗方法。获得NIH独立之路奖（K99/R 00）将使我能够在该奖项的指导阶段获得额外的研究培训，其中包括职业发展部分概述的活动，如研讨会，期刊俱乐部，科学会议，研究技术和教学课程的额外培训以及接触干细胞生物学的尖端技术。通过额外的培训，我将能够在一个高排名的学术和研究环境中从事独立的研究工作，重点是在该奖项的独立阶段进行翻译研究。 我在资助指导阶段的职业目标包括在高影响力期刊上发表三篇第一作者论文，学习表观遗传学和计算生物学的研究技术，并完成职业发展活动以提高我的科学背景。我的长期职业目标在指导阶段的补助金包括建立一个成功的独立研究计划，出版作为一个资深作者在高影响力的期刊，并通过NIH R 01的或其他机制获得独立的资金。最终，我希望我的工作能为理解HSC生物学及其与人类疾病状态的相关性做出重大贡献，并将我的研究结果转化为新的临床治疗策略。 工作环境：贝勒医学院（Baylor College of Medicine）是一所致力于研究，揭开人体奥秘，寻找治疗疾病和改善健康的新方法的一流研究机构。作为细胞和基因治疗中心（CAGT）和干细胞和再生医学（星星）中心的一部分，我将有机会使用各种核心设施，这些设施具有微阵列，流式细胞术，显微镜和胚胎干细胞方面的专业知识，并可以使用高水平，无病原体的屏障，利用通风机架，具有有限的访问安全系统。此外，这些中心的教师的不同兴趣包括造血，干细胞生物学，造血干细胞移植，基因治疗，免疫治疗和载体开发，并提供了充分的合作机会，以进一步我的科学培训。 调研：从我的博士后工作中，我已经确定了一个关于DNA甲基化在造血干细胞（HSC）谱系命运规范中的作用的项目。我已经确定，在HSC亚型之间存在DNA甲基转移酶的差异表达，骨髓偏向性HSC表达更高水平的Dnmt 3a，淋巴偏向性HSC具有更高水平的Dnmt 3b表达，并且我假设HSC谱系命运决定至少部分地由DNA甲基转移酶的作用控制。在这项研究中，我建议检查DNA甲基转移酶Dnmt 3a和Dnmt 3b在HSC中的功能作用。本文提出的实验将揭示DNA甲基化在HSC功能中的作用，并开始揭示调节干细胞生物学的表观遗传机制。 越来越多的证据表明表观遗传机制在基因转录和正常细胞功能调节中的重要性，这一研究领域代表了干细胞研究的下一个主要问题。此外，有充分的证据表明，异常的DNA甲基化以一些尚未确定的方式导致各种人类疾病，包括某些造血系统疾病。我相信这个项目中概述的基础研究可以有助于对干细胞功能的表观遗传调控的基本理解，并与人类疾病状态的进展直接相关。 公共卫生相关性：DNA甲基化异常与多种白血病相关，但其机制和预后意义尚不清楚。用抑制DNA甲基化的药物治疗髓性白血病患者可以改善临床结局，某些肿瘤抑制基因的DNA甲基化模式可以预测急性髓性白血病患者临床缓解后复发的风险。这里提出的实验将揭示DNA甲基化在正常造血干细胞功能中的作用，这将有望提供对异常DNA甲基化如何导致某些白血病的深入了解。

DESCRIPTION (provided by applicant): Candidate: I have been a post-doctoral researcher in the lab of Prof. Margaret Goodell at Baylor College of Medicine (Houston, TX) for three years, coming from a Ph.D. at the University of Queensland (Brisbane, QLD, Australia) in May, 2006. I obtained an initial fellowship from the Australian NHMRC to fund the first two years of my post-doc, during which I have studied the molecular regulation of hematopoietic stem cell differentiation and the epigenetic mechanisms that control stem cell fate. I am now applying for more senior fellowships and beginning to take the initial steps to establishing my own research programs. The timing of this application represents a crossroads in my career, where I am beginning to transition to independence and initiate my own research programs. My work in understanding the molecular regulation of hematopoietic stem cells is motivated by a desire to improve the lives of patients afflicted with hematopoietic disorders and my ultimate career goal is to see the implementation of meaningful discoveries in HSC biology to help drive novel clinical outcomes. I believe that the work outlined in this proposal could ultimately lead to novel therapeutic approaches for a wide range of patients. Obtaining an NIH Pathway to Independence Award (K99/R00) will allow me to gain additional research training in the mentored phase of the award with activities outlined in the career development section such as seminars, journal clubs, scientific conferences, additional training in research techniques and didactic coursework as well as exposure to cutting edge techniques in stem cell biology. With additional training, I will be able to pursue an independent research position in a highly ranked academic and research environment with an emphasis in translational research during the independent phase of the award. My career goals during the mentored phase of the grant include publishing three first-author papers in high-impact journals, learning research techniques in epigenetics and computational biology and completing the career development activities to enhance my scientific background. My long-term career goals during the mentored phase of the grant include establishment of a successfully independent research program, publishing as a senior author in high-impact journals and obtaining independent funding through NIH R01's or other mechanisms. Ultimately, I would like my work to make a significant contribution to the understanding of HSC biology and its relevance to human disease states and to translate findings from my research into novel clinical treatment strategies. Environment: Baylor College of Medicine (BCM) is a premier research institute that is committed to research, unraveling the mysteries of the human body, and finding new ways to cure disease and improve health. As part of the Center for Cell and Gene Therapy (CAGT) and the Stem Cells and Regenerative Medicine (STaR) Center, I will have access to diverse core facilities with expertise in microarray, flow cytometry, microscopy and embryonic stem cells as well as access to a high-level, pathogen-free barrier utilizing ventilated racks with a limited access security system. Moreover, the diverse interests of the faculty of these Centers includes hematopoiesis, stem cell biology, hemopoietic stem cell transplantation, gene therapy, immunotherapy, and vector development and provides ample opportnity for collaboration to further my scienific training. Research: From my post-doctoral work, I have identified a project concerning the role of DNA methylation in hematopoietic stem cell (HSC) lineage fate specification. I have determined that there is differential expression of DNA methyltransferase enzymes between HSC subtypes, with myeloid-biased HSCs expressing higher levels of Dnmt3a and lymphoid-biased HSCs having higher expression of Dnmt3b, and I hypothesize that HSC lineage fate determination is at least partly controlled by the actions of DNA methyltransferases. In this study I propose to examine the functional effects of the DNA methyltransferases Dnmt3a and Dnmt3b in HSCs. The experiments proposed here will shed new light on the role of DNA methylation in HSC function and begin to uncover the epigenetic mechanisms regulating stem cell biology. There is mounting evidence for the importance of epigenetic mechanisms in the regulation of gene transcription and normal cell function, and this field of study represents the next major question in stem cell research. Moreover, there is ample evidence suggesting aberrant DNA methylation contributes in some as of yet undefined ways to various human diseases including certain hematopoietic disorders. I believe the basic research outlined in this project can contribute to the fundamental understanding of epigenetic regulation of stem cell function and has direct relevance to progression of human disease states. PUBLIC HEALTH RELEVANCE: Aberrant DNA methylation has been associated with various leukemias, however the mechanisms involved and prognostic implications of this are not understood. Treatment of myeloid leukemia patients with drugs inhibiting DNA methylation has improved clinical outcomes and DNA methylation patterns of certain tumor suppressor genes can predict the risk of relapse of acute myeloid leukemia patients in clinical remission. The experiments proposed here will shed new light on the role of DNA methylation in normal hematopoietic stem cell function which will hopefully provide insight into how abnormal DNA methylation contributes to certain leukemias.