Impact of aging and clonal hematopoiesis on epigenetic heterogeneity, evolvability, and leukemogenesis

衰老和克隆造血对表观遗传异质性、进化性和白血病发生的影响

• 批准号: 10353178
• 负责人: James V Degregori
• 金额: $ 42.31万
• 依托单位: JACKSON LABORATORY
• 依托单位国家: 美国
• 财政年份: 2021
• 资助国家: 美国
• 起止时间: 2021-09-23 至 2026-08-31
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/10353178
• 关键词: Acute Myelocytic Leukemia; Adult; Age; Aging; Bar Codes; Blood; Bone Marrow; Cell Nucleus; Cells; Chromatin; Clonal Evolution; Clonal Expansion; Clone Cells; DNA; Development; Elderly; Enhancers; Environment; Epigenetic Process; Evolution; Exhibits; FLT3 gene; Foundations; Gene Expression Regulation; Gene Mutation; Genes; Genetic; Genomics; Hematopoiesis; Hematopoietic Neoplasms; Hematopoietic stem cells; Heterogeneity; Individual; Inflammation; Joints; Malignant - descriptor; Malignant Neoplasms; Mediating; Molecular Profiling; Mus; Mutation; Pathway interactions; Phenotype; Population; Process; Risk Factors; Somatic Mutation; Stress; Supporting Cell; Therapeutic; Time; Transplantation; age related; aged; bisulfite sequencing; bone aging; cancer initiation; epigenetic regulation; epigenomics; fitness; high risk; human old age (65+); insight; leukemia; leukemic transformation; leukemogenesis; methylome; mutant; novel therapeutic intervention; prevent; preventive intervention; promoter; resilience; response; self-renewal; single-cell RNA sequencing; stem cell biology; stem cell function; stem cell proliferation; transcriptome; transcriptomics; tumor heterogeneity

PROJECT SUMMARY Acute myeloid leukemia (AML) occurs mostly in adults 65 years and older and is associated with age-related clonal hematopoiesis (CH). This condition that results from the clonal expansion of mutationally-marked hematopoietic stem and progenitor cells (HSPC). These HSPC expansions often feature somatic mutations in leukemia-associated genes such as the epigenetic regulator TET2. TET2-mutant CH is a risk factor for AML, and CH progression to AML is promoted by acquiring cooperating mutations such as constitutively active FLT3ITD. Yet, it is unclear how aging and TET2 mutation interact to drive the evolution of CH to leukemia. We seek to reveal the epigenetic mechanisms for how CH evolves to leukemia in an aging microenvironment, laying the foundation for therapeutic strategies to block this evolution and prevent leukemia in the aging US population. To this end, we will leverage our team's complementary expertise in intra-tumor heterogeneity and computational epigenomics; aging, cancer evolution, and leukemogenesis; inflammation and hematopoietic stem cell (HSC) biology; and mouse HSC proliferation and functional heterogeneity. Our preliminary results in mice show that HSPC epigenetic heterogeneity increases in old age. This process occurs in an aged bone marrow (BM) microenvironment characterized by inflammation and altered HSPC support. The rise of epigenetic and transcriptomic heterogeneity in HSC with Tet2 mutation (Tet2MT) and Flt3ITD precedes leukemic transformation. We hypothesize that aging and TET2 mutation cooperatively enhance epigenetic heterogeneity and evolvability of HSPC, thus contributing to clonal expansion and leukemogenesis. In Aim 1, we will determine the combined impact of aging and Tet2MT on epigenetic heterogeneity and gene regulation in HSPC by examining the somatic epigenomic landscape of Tet2MT HSPC from young (2-3 months) and old (22 months) mice, including single-cell (sc) transcriptomes by scRNA-seq, open-chromatin profiles by snATAC-seq, and DNA methylomes by RRBS. We expect to define epigenetic configurations in old Tet2MT HSPC associated with genes in self-renewal, quiescence, and responses to inflammation and stress. In Aim 2, we will define epigenetic configurations of Tet2MT HSPC that are adaptive in the aged context. We will transplant genetically barcoded HSPC into young or old mice and assess subclone expansion/contraction to determine if an age-dependent selection is for all Tet2MT HSPC or only a subset. We will use scRNA-seq and snATAC-seq to define molecular signatures and epigenetic heterogeneity of barcoded HSPC that are positively selected in the aged context. In Aim 3, we will define the epigenetic configurations of Tet2MT HSPC that are permissive to Flt3ITD-induced transformation in the aged context. We will transduce the Flt3ITD gene into young or aged Tet2MT or wild-type HSC and then transplant these genetically barcoded cells into young or old host mice. We will assess the epigenetic profiles of the selected HSPC by scRNA-seq and scATAC-seq of their identified progeny. We expect our findings will shift the paradigm for how epigenetic plasticity promotes somatic evolution and leads to cancer initiation in aging individuals.

项目概要 急性髓系白血病 (AML) 主要发生在 65 岁及以上的成年人中，并且与年龄相关 克隆造血（CH）。这种情况是由突变标记的克隆扩增引起的 造血干细胞和祖细胞（HSPC）。这些 HSPC 扩增通常以体细胞突变为特征 白血病相关基因，例如表观遗传调节因子 TET2。 TET2 突变 CH 是 AML 的危险因素， 通过获得协同突变（例如组成型活性 FLT3ITD），可以促进 CH 进展为 AML。 然而，目前尚不清楚衰老和 TET2 突变如何相互作用以驱动 CH 演变为白血病。我们力求 揭示老化微环境中CH如何演变为白血病的表观遗传机制，奠定了 为阻止这种演变并预防美国老龄化人口中的白血病的治疗策略奠定了基础。到 为此，我们将利用我们团队在肿瘤内异质性和计算方面的互补专业知识 表观基因组学；衰老、癌症演变和白血病发生；炎症与造血干细胞 (HSC) 生物学;以及小鼠 HSC 增殖和功能异质性。我们在小鼠身上的初步结果表明 HSPC 表观遗传异质性在老年时增加。这个过程发生在老化的骨髓 (BM) 中 以炎症和 HSPC 支持改变为特征的微环境。表观遗传学的兴起和 具有 Tet2 突变 (Tet2MT) 和 Flt3ITD 的 HSC 中的转录组异质性先于白血病转化。 我们假设衰老和 TET2 突变共同增强表观遗传异质性和进化性 HSPC，从而有助于克隆扩增和白血病发生。在目标 1 中，我们将确定组合 通过检查体细胞衰老和 Tet2MT 对 HSPC 表观遗传异质性和基因调控的影响 来自年轻（2-3 个月）和年老（22 个月）小鼠的 Tet2MT HSPC 表观基因组图谱，包括单细胞 (sc) scRNA-seq 的转录组、snATAC-seq 的开放染色质图谱以及 RRBS 的 DNA 甲基化组。 我们期望定义旧 Tet2MT HSPC 中与自我更新基因相关的表观遗传配置， 静止以及对炎症和压力的反应。在目标 2 中，我们将定义表观遗传配置 Tet2MT HSPC 在老年环境中具有适应性。我们将把带有基因条形码的 HSPC 移植到年轻或 年老小鼠并评估亚克隆扩张/收缩，以确定年龄依赖性选择是否适用于所有 Tet2MT HSPC 或只是一个子集。我们将使用 scRNA-seq 和 snATAC-seq 来定义分子特征和表观遗传 在老龄环境中积极选择的条形码 HSPC 的异质性。在目标 3 中，我们将定义 Tet2MT HSPC 的表观遗传配置允许 Flt3ITD 诱导的老年人转化 语境。我们将Flt3ITD基因转导到年轻或年老的Tet2MT或野生型HSC中，然后移植这些 将带有基因条形码的细胞植入年轻或年老的宿主小鼠中。我们将评估所选对象的表观遗传特征 通过 scRNA-seq 和 scATAC-seq 对其鉴定的后代进行 HSPC。我们预计我们的发现将改变范式 研究表观遗传可塑性如何促进体细胞进化并导致衰老个体发生癌症。