Lineage bias and clonal expansion of hematopoietic stem cell differentiation

描述（由申请人提供）：我的近期职业目标是成为干细胞的独立研究者，专注于临床相关压力下单细胞水平的造血干细胞分化。我的长期研究目标是确定造血干细胞在维持平衡的血液系统中是如何协调的，以及这种协调的调节机制如何与血液疾病相关。我在普林斯顿大学攻读博士学位期间，在Ihor R。Lemischka和专业知识的细胞生物学博士的指导下，欧文L。韦斯曼在斯坦福大学。我精通多种编程语言，包括C/C++，R，Matlab和Python，我可以独立设计和执行现代定量生物学所需的高级统计分析。利用这些跨学科的技能，我最近开发了一种新的，单细胞在体内跟踪系统featurig高灵敏度和高通量。我们使用该系统的初步研究证实了以前的报告在小鼠中的HSC谱系偏见。此外，我们还发现了一个以前未发现的现象：辐射介导的移植后的大多数血细胞来自于一小部分移植的HSC克隆的急剧扩增。更引人注目的是，虽然在辐射介导的移植后通常观察到谱系偏倚和克隆扩增，但它们在非条件移植后不存在。因此，我们假设谱系偏好和克隆扩增不是先天的HSC特征，而是由外源性造血应激如辐射引发的行为。在这项研究中，我们建议在各种移植条件下（K99期）在小鼠中进一步验证这一假设，并确定谱系偏倚和克隆扩增是否相关（K99期/R 00期）以及它们是否是HSC克隆的先天决定性特征（R 00期）。除了这些体内小鼠研究之外，我们还将研究在克隆水平（R 00期）异种移植到小鼠中的人HSC。这些拟议的研究将阐明造血稳态是如何在破坏后重新建立的，并将辐射诱导的效应与天然的先天细胞特性分开。研究结果将有助于改善与血液系统不平衡相关的疾病的治疗，并可能导致解决方案，减少辐射在临床应用和持续低水平辐射暴露的职业中的副作用。我的K99期培训将由著名的造血干细胞专家欧文L博士指导。在斯坦福大学医学院干细胞生物学和再生医学研究所的世界一流的机构环境中。除了让我完成拟议的研究，K99培训也将大大提高我的知识和经验与我的研究的临床应用。此外，它将帮助我找到一个独立的研究职位，并提供初步的支持，以准备我的第一个R 01申请。

DESCRIPTION (provided by applicant): My immediate career goal is to become an independent investigator of stem cells, focusing on hematopoietic stem cell differentiation at the single cell level under clinically relevant stresses. My long-term research goal is to determine how hematopoietic stem cells are coordinated in sustaining a balanced blood system and how the regulatory mechanisms of this coordination are related to blood disorders. I have a strong background in molecular biology from my PhD training at Princeton University under the guidance of Dr. Ihor R. Lemischka and expertise in cell biology under the mentoring of Dr. Irving L. Weissman at Stanford University. I am proficient with several programming languages including C/C++, R, Matlab, and Python, and I can independently design and carry out the advanced statistical analyses required for modern quantitative biology. Using these cross-disciplinary skills, I have recently developed a novel, single cell in vivo tracking system featurig high sensitivity and high throughput. Our preliminary studies using this system confirm previous reports of HSC lineage bias in mice. In addition, we have discovered a previously undetected phenomenon: the majority of blood cells after irradiation-mediated transplantation are derived from the dramatic expansion of a small subset of engrafted HSC clones. More strikingly, while lineage bias and clonal expansion are commonly observed after irradiation-mediated transplantation, they are not present after unconditioned transplantation. Therefore, we hypothesize that lineage bias and clonal expansion are not innate HSC characteristics, but instead are behaviors initiated by exogenous hematopoietic stresses such as irradiation. In this grant, we propose to further test this hypothesis in mice under various transplantation conditions (K99 phase) as well as to determine whether lineage bias and clonal expansion are related (K99 phase / R00 phase) and whether they are innate deterministic features of HSC clones (R00 phase). In addition to these in vivo mice studies, we will also investigate human HSCs xenotransplanted into mice at the clonal level (R00 phase). These proposed studies will elucidate how hematopoietic homeostasis is re-established after disruption and will separate irradiation-induced effects from natural innate cellular properties. The results will help to improe the treatment of diseases associated with an unbalanced blood system and may lead to solutions that reduce the side effects of radiation in clinical applications and in occupations wit constant low levels of radiation exposure. My K99 phase training will be mentored by the distinguished hematopoietic stem cell expert Dr. Irving L. Weissman, in a world-class institutional environment at the Institute for Stem Cell Biology and Regenerative Medicine at Stanford University School of Medicine. In addition to allowing me to finish the proposed research, the K99 training will also substantially enhance my knowledge and experience with the clinical applications of my research. In addition, it will help me locate an independent research position and provide the initial support to prepare for my first R01 application.