Extrinsic regulation of primitive, myeloid-biased hematopoietic stem cells by Semaphorin 4a

Semaphorin 4a 对原始骨髓造血干细胞的外在调节

• 批准号: 10656520
• 负责人: Lev Silberstein
• 金额: $ 48.7万
• 依托单位: FRED HUTCHINSON CANCER CENTER
• 依托单位国家: 美国
• 财政年份: 2021
• 资助国家: 美国
• 起止时间: 2021-01-01 至 2025-12-31
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/10656520
• 关键词: Age; Aging; Alleles; Animals; Binding; Biological; Biological Assay; Blood; Blood Platelets; Bone Marrow; Cells; Chronic; Clinical; Cytotoxic Chemotherapy; DNA Damage; Data; Development; Disease; Dysmyelopoietic Syndromes; Elderly; Endothelial Cells; Endothelium; Engraftment; Evolution; Exposure to; Functional disorder; Future; Gene Modified; Genetic; Genetic Models; Goals; Health Care Costs; Hematopoiesis; Hematopoietic; Hematopoietic Stem Cell subsets; Hematopoietic stem cells; Human; Impairment; In Vitro; Individual; Inflammation; Inflammatory; Inhibition of Cell Proliferation; Label; Long-Term Care for Elderly; LoxP-flanked allele; Malignant - descriptor; Mediating; Mesenchymal; Modeling; Molecular; Molecular Profiling; Mus; Myelogenous; Myeloid Progenitor Cells; Myeloproliferative disease; National Heart, Lung, and Blood Institute; National Institute of Diabetes and Digestive and Kidney Diseases; Natural regeneration; Pathogenesis; Pathway interactions; Pre-Clinical Model; Prevention; Prevention strategy; Procedures; Proliferating; Property; Proteins; Public Health; Recombinants; Recording of previous events; Regulation; Reporter; Research; Risk; Role; Semaphorins; Signal Pathway; Signal Transduction; Stem cell transplant; Stress; Testing; Therapeutic; Transplantation; United States National Institutes of Health; VWF gene; Xenograft procedure; age related; bone preservation; candidate validation; cell injury; cell motility; chemotherapy; clinically relevant; exhaustion; functional loss; gene correction; gene therapy; hematopoietic stem cell quiescence; hematopoietic stem cell self-renewal; improved; in vivo; innovation; insight; intravital imaging; intravital microscopy; mouse model; novel; osteoprogenitor cell; pharmacologic; plexin; premature; preservation; prevent; protective effect; receptor; reconstitution; regeneration function; regenerative; self-renewal; senescence; single-cell RNA sequencing; stem cell function; stem cell proliferation; stem cells; success; transcriptomics; translational study

ABSTRACT Despite substantial experimental evidence for the important functional role of myeloid-biased HSC (myHSC) in stress, inflammation and aging, the mechanisms which control myHSC quiescence and self-renewal are not known. The long-term goal of this project is to understand how myHSC self-renewal can be regulated by the bone marrow microenvironment in order to identify novel signaling pathways that can be activated to enhance hematopoietic regeneration, and blocked if they become dysregulated in myeloid malignancy. The overall objective in this application is to understand at the mechanistic level how Sema4a, a newly-defined niche factor, selectively promotes quiescence and self-renewal of myHSC, and to test potential therapeutic utility of its pro-regenerative effect in clinically relevant models of proliferative stress and HSC exhaustion. The central hypothesis is that Sema4a is released from osteoprogentiors and endothelial cells in the bone marrow microenvironment and binds to Plexin D1 on myHSC, which triggers a cascade of inhibitory signals that shield myHSC from exhaustion, premature differentiation and DNA damage. The rationale for this project is that identification of Sema4a-induced myHSC-specific pathways and testing their protective effect on myHSC in pre-clinical models of proliferative stress is likely to offer a strong scientific framework for future therapeutic strategies to improve myHSC self-renewal and hematopoietic regeneration. The central hypothesis will be tested under two specific aims: 1) Determine molecular and cellular mechanisms of Sema4a effects on myHSC; and 2) Define therapeutic opportunities for Sema4a as a myHSC “protector” from proliferative stress. Under the first aim, genetic mouse models, single-cell RNA Sequencing and intravital microscopy will be used to evaluate the effect of microenvironmental deletion of Sema4a or its putative receptor, Plexin D1, on myHSC and to uncover the role of Sema4a as myHSC-specific hematopoietic regulator. Under the second aim, my- HSC protective properties of Sema4a will be explored in clinically relevant models of functional HSC loss, such as exposure to cytotoxic chemotherapy and ex-vivo HSC culture during gene modification procedure. The research proposed in this application is innovative, in candidate’s opinion, because it builds on a novel discovery of Sema4a as a potent and indispensable regulator of myHSC in vivo, and provides substantive new experimental evidence for the concept that functionally specialized HSC are controlled by distinct regulatory circuits. The proposed research is significant because it is expected to serve as a scientific justification for future therapeutic strategies to improve hematopoietic regeneration following chemotherapy and stem cell transplantation, enhance engraftment of gene-modified HSC and prevent myeloid bias, age-related HSC dysfunction and evolution to myeloid malignancy in the elderly.

抽象的 尽管有大量实验证据表明偏向髓系的 HSC (myHSC) 在 压力、炎症和衰老，控制 myHSC 静止和自我更新的机制并不 已知。该项目的长期目标是了解 myHSC 自我更新如何通过 骨髓微环境，以确定可被激活以增强的新信号传导途径 造血再生，如果它们在骨髓恶性肿瘤中失调，就会受到阻碍。整体 此应用程序的目标是从机制层面了解 Sema4a（一个新定义的利基市场）如何 因子，选择性促进 myHSC 的静止和自我更新，并测试其潜在的治疗效用 其在临床相关的增殖应激和 HSC 耗竭模型中的促再生作用。中央 假设 Sema4a 是从骨髓中的骨祖细胞和内皮细胞释放的 微环境并与 myHSC 上的 Plexin D1 结合，触发一系列抑制信号，从而屏蔽 myHSC 免受衰竭、过早分化和 DNA 损伤的影响。该项目的理由是 鉴定 Sema4a 诱导的 myHSC 特异性途径并测试其对 myHSC 的保护作用 增殖应激的临床前模型可能为未来的治疗提供强有力的科学框架 改善 myHSC 自我更新和造血再生的策略。中心假设将是 在两个特定目标下进行测试：1) 确定 Sema4a 影响的分子和细胞机制 我的HSC； 2) 定义 Sema4a 作为 myHSC 免受增殖应激的“保护者”的治疗机会。 第一个目标将使用遗传小鼠模型、单细胞 RNA 测序和活体显微镜 评估微环境删除 Sema4a 或其推定受体 Plexin D1 对 myHSC 的影响 并揭示 Sema4a 作为 myHSC 特异性造血调节因子的作用。在第二个目标下，我的—— Sema4a 的 HSC 保护特性将在功能性 HSC 丧失的临床相关模型中进行探索，例如 如在基因修饰过程中暴露于细胞毒性化疗和离体 HSC 培养。这 在候选人看来，本申请中提出的研究具有创新性，因为它建立在新颖的基础上 发现 Sema4a 作为 myHSC 体内有效且不可或缺的调节剂，并提供了实质性的新成果 功能特化 HSC 受不同监管控制这一概念的实验证据 电路。拟议的研究意义重大，因为它有望作为科学论证 改善化疗和干细胞后造血再生的未来治疗策略 移植，增强基因修饰 HSC 的植入并防止骨髓偏向、年龄相关 HSC 老年人的功能障碍和向骨髓恶性肿瘤的演变。