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: 10462192
• 负责人: Iannis Aifantis
• 金额: $ 65.3万
• 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/10462192
• 关键词: Acetylation; Acute Myelocytic Leukemia; Affect; Aging; Agonist; Applications Grants; Binding; Biological Assay; Cell physiology; Cells; Clinical; 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; 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; Risk; Role; Signal Transduction; TRAF6 gene; Therapeutic; Toll-like receptors; Tumor Suppressor Proteins; Ubiquitin; Ubiquitination; acute myeloid leukemia cell; base; disorder subtype; human disease; human stem cells; improved; in vivo; innate immune pathways; insight; leukemia; loss of function; mouse model; novel; promoter; protein expression; self-renewal; small hairpin RNA; 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)是一种衰老相关疾病，其特征是克隆性生长 突变的白血病前期细胞。尽管CH患者是健康的，但他们患上CH的风险增加 发展中的血液系统恶性肿瘤。以确定所需的协同分子改变 克隆性白血病前期HSPC的恶性转化，我们进行了体内shRNA筛选，并发现 靶向Traf6的shRNAs在转化为明显的髓系细胞后得到了压倒性的丰富 白血病。TRAF6是一种泛素E3连接酶，可合成赖氨酸(K)63连接的泛素链 导致Toll样受体(TLR)超家族通路激活的底物。以支持我们在体内的 ShRNA筛选、启动子超甲基化和TRAF6在亚群中表达降低 髓系恶性肿瘤患者，约占急性髓系白血病(AML)的40-50%。而且，我们的 初步数据显示，在白血病前期TET2缺陷的HSPC中，Traf6缺失导致侵袭性 髓系肿瘤部分通过一种新的MYC依赖机制。根据我们的发现，我们 假设TRAF6的缺失驱动了基因定义的髓系恶性肿瘤的亚群，特别是 通过一种新的MYC翻译后修饰导致其激活。该提案的目标 旨在揭示TRAF6缺失对白血病前期HSPC功能的分子和细胞基础 通过调查以下疾病的后果来发现改进的治疗方法的长期目标 TRAF6缺失在CH和白血病发生发展模型中的作用(目标1)，确定TRAF6缺失的分子基础 TRAF6在急性髓系白血病中的抑瘤样功能(AIM 2)，并评价A 新的依赖TRAF6的MYC翻译后修饰(目标3)。这些研究具有非常重要的意义 因为它们将提供对白血病前期状态发展为显性白血病的关键洞察力 在颠覆选定的先天免疫途径方面，描述了TLR-TRAF6的新的疾病修改作用，以及 揭示了一种未报道的MYC调控机制。这些研究具有直接的翻译意义。 并填补了对AML/MPN基因和表型定义的亚型的临床需求。