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

基本信息

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
项目类别：
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

项目摘要

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.

抽象的克隆性造血（CH）是一种与衰老相关的疾病，其特征是克隆性生长突变的前白血病细胞。尽管慢性肝炎患者身体健康，但他们罹患慢性疾病的风险增加发展为造血系统恶性肿瘤。确定所需的合作分子改变针对克隆性白血病前期 HSPC 的恶性转化，我们进行了体内 shRNA 筛选，发现靶向 Traf6 的 shRNA 在转化为显性骨髓细胞后得到压倒性富集白血病。 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) 超家族途径激活的底物。支持我们的体内在 shRNA 筛选、启动子高甲基化和 TRAF6 表达减少的子集中观察到骨髓恶性肿瘤患者，包括约 40-50% 的急性髓系白血病 (AML)。此外，我们的初步数据表明，在白血病前期 Tet2 缺陷的 HSPC 中删除 Traf6 会导致攻击性的骨髓肿瘤部分通过一种新的 MYC 依赖性机制。根据我们的发现，我们假设 TRAF6 的缺失会导致基因定义的骨髓恶性肿瘤的子集，特别是通过 MYC 的新型翻译后修饰导致其激活。提案的目标旨在揭示 TRAF6 缺失对白血病前 HSPC 功能的分子和细胞基础通过调查后果来发现改进的治疗方法的长期目标 CH 模型和白血病发展中的 TRAF6 缺失（目标 1），确定了 TRAF6 缺失的分子基础 TRAF6 在 AML 中的肿瘤抑制样功能（目标 2），并评估 TRAF6 的致癌潜力新型 TRAF6 依赖性 MYC 翻译后修饰（目标 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重要的见解颠覆选择的先天免疫途径，描述 TLR-TRAF6 的新疾病缓解作用，以及揭示了未报道的 MYC 调节机制。这些研究具有直接的转化意义并填补对基因和表型定义的 AML/MPN 亚型的未满足的临床需求。