Dissecting innate immune signaling in pre-leukemia evolution

剖析白血病前期进化中的先天免疫信号

• 批准号: 10584536
• 负责人: Iannis Aifantis
• 金额: $ 62.55万
• 依托单位: CINCINNATI CHILDRENS HOSP MED CTR
• 依托单位国家: 美国
• 财政年份: 2022
• 资助国家: 美国
• 起止时间: 2022-03-04 至 2027-02-28
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/10584536
• 关键词: Acetylation; Acute Myelocytic Leukemia; Affect; Aging; Agonist; Applications Grants; Binding; Biological Assay; Cell physiology; Cells; Clinical; DNMT3a; Data; Development; Disease; Dysmyelopoietic Syndromes; Evolution; Gene Expression; Gene Expression Profiling; Genetic; Genetic Models; Goals; Hematopoiesis; Hematopoietic; Hematopoietic Neoplasms; Hematopoietic stem cells; Human; Hypermethylation; Immune signaling; Individual; Leukemic Cell; Link; Lysine; Malignant - descriptor; Mediating; Messenger RNA; Modeling; Modification; Molecular; Mus; Mutate; Mutation; Myeloid Leukemia; Myeloproliferative disease; Oncogenic; Outcome; Pathway interactions; Patients; Phenotype; Post-Translational Protein Processing; Preleukemia; Proteins; Proteomics; RNA Splicing; RNA interference screen; Regulation; Repression; Risk; Role; Signal Transduction; TRAF6 gene; Therapeutic; Toll-like receptors; Tumor Suppressor Proteins; Ubiquitin; Ubiquitination; acute myeloid leukemia cell; disorder subtype; human disease; improved; in vivo; innate immune pathways; insight; leukemia; loss of function; mouse model; novel; promoter; protein expression; self-renewal; small hairpin RNA; stem; stem cell function; stem cells; transcriptome; tumor; ubiquitin-protein ligase

Abstract Clonal hematopoiesis (CH) is an aging associated condition characterized by the clonal outgrowth of mutated pre-leukemic cells. Although individuals with CH are healthy, they are at an increased risk of developing hematopoietic malignancies. To identify cooperating molecular alterations required for malignant transformation of clonal pre-leukemic HSPC, we performed an in vivo shRNA screen and found that shRNAs targeting Traf6 were overwhelmingly enriched in following transformation to overt myeloid leukemias. TRAF6 is an ubiquitin E3 ligase that synthesizes Lysine (K) 63-linked ubiquitin chains on substrates leading to Toll-like receptor (TLR) superfamily pathway activation. In support of our in vivo shRNA screen, promoter hypermethylation and reduced expression of TRAF6 is observed in subsets of myeloid malignancy patients, including ~40-50% of acute myeloid leukemia (AML). Moreover, our preliminary data shows that deletion of Traf6 in pre-leukemic Tet2-deficient HSPC results in an aggressive myeloid neoplasm in part through a novel MYC-dependent mechanism. Based on our findings, we hypothesize that loss of TRAF6 drives subsets of genetically-defined myeloid malignancies, specifically via a novel post-translational modification of MYC resulting in its activation. The objectives of the proposal are to uncover the molecular and cellular basis of TRAF6 deletion on pre-leukemic HSPC function with the long-term goal of uncovering improved therapeutic approaches by investigating the consequences of TRAF6 deletion in models of CH and on leukemia development (Aim 1), identifying the molecular basis of the tumor suppressor-like function of TRAF6 in AML (Aim 2), and evaluating the oncogenic potential of a novel TRAF6-dependent MYC post-translational modification (Aim 3). These studies are highly significant as they will provide critical insight into the progression of pre-leukemic states to overt leukemia as a result of subverting select innate immune pathways, describe a novel disease-modifying role of TLR-TRAF6, and reveal an unreported mechanism of MYC regulation. These studies have direct translational implications and fill an unmet clinical need for genetically- and phenotypically-defined subtypes of AML/MPN.

摘要 克隆性造血（CH）是一种衰老相关的疾病，其特征在于 突变的前白血病细胞虽然患有CH的个体是健康的，但他们的风险增加， 发展成造血系统恶性肿瘤为了确定协同分子改变所需的 恶性转化的克隆前白血病HSPC，我们进行了体内shRNA筛选，发现 靶向Traf 6的shRNAs在转化为明显的髓样细胞后绝大多数富集， 白血病TRAF 6是一种泛素E3连接酶，其合成赖氨酸（K）63-连接的泛素链， Toll样受体（TLR）超家族途径激活的底物。为了支持我们的体内 shRNA筛选、启动子高甲基化和TRAF 6表达减少在以下亚组中观察到： 骨髓恶性肿瘤患者，包括约40-50%的急性髓性白血病（AML）。而且我们 初步数据显示，在白血病前期Tet 2缺陷型HSPC中Traf 6的缺失导致侵袭性细胞凋亡。 骨髓肿瘤部分通过新型MYC依赖性机制来实现。根据我们的发现，我们 假设TRAF 6的缺失驱动遗传学定义的骨髓恶性肿瘤的亚群，特别是 通过一种新的MYC翻译后修饰导致其激活。提案的目标 目的是揭示TRAF 6缺失对白血病前HSPC功能的分子和细胞基础， 长期目标是通过调查以下因素的后果来发现改进的治疗方法： CH模型和白血病发展中的TRAF 6缺失（目的1），确定 TRAF 6在AML中的肿瘤抑制样功能（目的2），并评估TRAF 6的致癌潜力。 新的TRAF 6依赖性MYC翻译后修饰（Aim 3）。这些研究意义重大 因为它们将为白血病前期状态发展为明显的白血病提供关键的见解 颠覆选择的先天免疫途径，描述了TLR-TRAF 6的一种新的疾病修饰作用， 揭示了MYC调控的一种未报道的机制。这些研究具有直接的翻译意义 并填补了对AML/MPN的基因和表型定义亚型的未满足的临床需求。