Project 4: Impact of cardiovascular disease on proliferation and genetic diversity of hematopoietic stem cells

项目4：心血管疾病对造血干细胞增殖和遗传多样性的影响

• 批准号: 10670736
• 负责人: Kamila Naxerova
• 金额: $ 41.32万
• 依托单位: MASSACHUSETTS GENERAL HOSPITAL
• 依托单位国家: 美国
• 财政年份: 2019
• 资助国家: 美国
• 起止时间: 2019-08-01 至 2024-07-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/10670736
• 关键词: Acceleration; Acute; Address; Affect; Age; Aging; Atherosclerosis; Bar Codes; Behavior; Blood; Bone Marrow; Bone Marrow Purging; Cardiovascular Diseases; Cell Compartmentation; Cells; Chronic; Clonal Expansion; Clonal Hematopoietic Stem Cell; Collaborations; Collection; Complement; DNA; Data; Development; Disease; Disease model; Etiology; Evolution; Exhibits; Experimental Models; Gene Library; Genes; Genetic; Genetic Drift; Genetic Models; Genetic Variation; Genotype; Goals; Hematopoiesis; Hematopoietic; Hematopoietic stem cells; Human; Immune; Incidence; Individual; Inflammatory; Lentivirus; Letters; Measures; Methodology; Methods; Modeling; Mus; Mutate; Mutation; Myocardial Infarction; Nature; Patients; Pattern; Peripheral; Phenotype; Population; Population Dynamics; Process; Proliferating; Proteins; Role; Scientist; Testing; Time; Titrations; Transplantation; Untranslated RNA; Work; atherosclerosis risk; cardiovascular disorder risk; clinically relevant; exhaustion; experience; experimental study; genetic analysis; in silico; in vivo; insertion/deletion mutation; insight; interest; mathematical model; mouse model; next generation; novel; peripheral blood; self-renewal; stem cell population; stem cell proliferation

During aging, descendants of individual hematopoietic stem cell (HSC) clones can begin dominating significant portions of the peripheral blood, a phenomenon called clonal hematopoiesis (CH). CH has recently been shown to correlate with an increased risk for CVD. The mechanisms behind this association are only beginning to be explored. Existing studies have focused on examining how driver genes that are frequently mutated in CH affect the inflammatory phenotype of peripheral immune cells that drive CVD. Here, we propose to investigate the possibility of reverse causality. We will study how CVD influences HSC evolution and CH emergence, using mathematical modeling and novel experimental methods. In aim 1, we will construct a mathematical model of somatic HSC evolution in steady state and CVD. Myocardial infarction has been shown to double the proliferation rate of HSCs. Furthermore, our unpublished preliminary data, collected in collaboration with other PPG projects, show that atherosclerosis can similarly increase the proliferation of HSCs by up to 2.5-fold. We hypothesize that chronically elevated proliferation in the HSC compartment accelerates CH due to neutral drift and/or due to accelerated emergence of clones with a selective advantage. To test these hypotheses, we will construct a stochastic branching process model of genetic diversity in the HSC population over a human lifetime. We will begin by studying neutral drift alone and will then carefully expand our model to include the occurrence of beneficial mutations. Results from this aim will elucidate the role of HSC proliferation in CH emergence and provide a firm quantitative basis for future research into the mechanisms of CH. In aim 2, we will investigate experimentally whether CVD causes clonal hematopoiesis in mice. We will establish murine models of CH and test our hypothesis that increased HSC proliferation rates caused by CVD enhance CH. We will use polyguanine genotyping, a genetic analysis that relies on non-coding, hypermutable DNA repeats which rapidly accumulate insertion/deletion mutations, to measure with high sensitivity whether clonal expansions occur in the blood of aging mice. We will then determine whether the incidence of CH is significantly increased in two CVD models (atherosclerosis and myocardial infarction). In Aim 2B, we will study CVD and CH in a transplantation setting. We will isolate and transduce highly purified LT-HSC populations with a lentivirus carrying a library of genetic barcodes, along with a collection of seven fluorescent proteins that can be used to track clonal dynamics in vivo. We will then transplant tagged HSCs into myeloablated hosts, titrating their numbers such that CH emerges within a relatively short time frame. Finally, we will induce myocardial infarction and atherosclerosis and score the incidence of CH in comparison to age-matched controls. In conjunction with our in silico approach in aim 1, we anticipate that these experiments will provide fundamental insights into how HSC population dynamics are influenced by CVD.

在衰老期间，个体造血干细胞（HSC）克隆的后代可以开始主导显着 外周血的一部分，一种称为克隆造血的现象（CH）。 CH最近是 证明与CVD风险增加相关。这种关联背后的机制才开始 要探索。现有研究的重点是检查如何经常突变的驱动基因 CH会影响驱动CVD的外周免疫细胞的炎症表型。在这里，我们建议 研究逆因果关系的可能性。我们将研究CVD如何影响HSC的进化和CH 出现，使用数学建模和新型实验方法。在AIM 1中，我们将构建一个 稳态和CVD中体体HSC演变的数学模型。心肌梗塞已显示 将HSC的增殖率加倍。此外，我们未发表的初步数据收集了 与其他PPG项目的合作，表明动脉粥样硬化可以同样增加 HSC高达2.5倍。我们假设HSC室中长期升高的增殖 由于具有选择性优势的克隆的出现而导致CH加速CH。 为了检验这些假设，我们将在遗传多样性中构建随机分支过程模型 HSC人口一生。我们将首先独自研究中性漂移，然后小心 扩展我们的模型以包括发生有益突变的发生。这个目标的结果将阐明 HSC增殖在CH出现中的作用，并为将来的研究提供了牢固的定量基础 ch的机制。在AIM 2中，我们将通过实验研究CVD是否引起克隆造血 老鼠。我们将建立CH的鼠模型并检验我们的假设，以提高HSC增殖率 由CVD提高CH。我们将使用多圭亚氨酸基因分型，这是一种依赖非编码的遗传分析， 高温DNA重复序列，迅速积累插入/缺失突变，以高度测量 敏感性是否存在于老化小鼠的血液中。然后，我们将确定是否 在两种CVD模型（动脉粥样硬化和心肌梗塞）中，CH的发生率显着增加。在 AIM 2B，我们将在移植环境中研究CVD和CH。我们将隔离并转导高度纯化 LT-HSC种群的慢跑病毒含有遗传条形码库，以及七个集合 荧光蛋白可用于跟踪体内克隆动力学。然后，我们将移植标记为HSCS 进入骨髓的宿主，滴定其数字，使CH在相对较短的时间范围内出现。 最后，我们将诱导心肌梗塞和动脉粥样硬化，并评分CH的发生率 到年龄匹配的控件。结合我们在AIM 1中的计算机方法1，我们预计这些 实验将为HSC人群动态如何受到CVD的影响提供基本见解。