Mechanisms of necrosis regulation of hematopoietic stem cell function

坏死调节造血干细胞功能的机制

• 批准号: 9921492
• 负责人: Sandra S Zinkel
• 金额: $ 39.5万
• 依托单位: VANDERBILT UNIVERSITY MEDICAL CENTER
• 依托单位国家: 美国
• 财政年份: 2018
• 资助国家: 美国
• 起止时间: 2018-05-03 至 2022-04-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/9921492
• 关键词: Age; Aging; Anemia; Aplastic Anemia; Apoptosis; Apoptotic; Automobile Driving; Blood; Bone Marrow; Bone Marrow Cells; Bone Marrow Transplantation; CASP8 gene; Caspase; Cell Count; Cell Death; Cell Death Signaling Process; Cell Proliferation; Cell physiology; Cells; Cessation of life; Cytokine Signaling; DNA Sequence Alteration; Data; Diagnosis; Disease; Dysmyelopoietic Syndromes; Environment; Epigenetic Process; Equilibrium; Erythroid; Erythroid Progenitor Cells; Etanercept; Excision; Genes; Genetic; Genetic Crosses; Goals; Granzyme; Hematopoiesis; Hematopoietic; Hematopoietic stem cells; Homeostasis; Human; Immune; Immune response; Impairment; Ineffective Hematopoiesis; Inflammatory; Inflammatory Response; Interferon Type II; Interruption; Light; Malignant Neoplasms; Methods; Molecular; Mus; Mutation; Myelogenous; Necrosis; Organism; Outcome; Pancytopenia; Pathway interactions; Patients; Phenotype; Phosphotransferases; Process; Production; RIPK1 gene; RNA Splicing; Regulation; Regulator Genes; Sampling; Serine Protease; Signal Pathway; Signal Transduction; TNF gene; TNFRSF1A gene; Testing; Therapeutic; Work; base; biobank; bone marrow failure syndrome; cell injury; cohort; cytokine; cytopenia; design; dynamic system; genome wide association study; improved; inhibitor/antagonist; leukemia; mouse model; mutant; novel; prevent; progenitor; programs; public health relevance; receptor; stem cells; targeted treatment

Normal hematopoiesis requires stringent control of production of new cells (proliferation) and removal of aging or damaged cells (programmed cell death). Patients with bone marrow failure disorders such as Myelodysplastic syndrome (MDS) have increased bone marrow programmed cell death, and increased levels of death-inducing cytokines such as TNFa. Discoveries in the last several years have demonstrated that in addition to apoptosis, TNFa also activates a novel form of cell death, programmed necrosis. Apoptotic cells implode in caspase-driven and immune silent process, whereas necrotic cells explode in a Rip kinase-driven process, releasing cellular contents (DAMPS) and eliciting an immune response. We find increased Rip1 kinase expression in 70% of MDS patient samples tested suggesting that necroptosis is activated in MDS. We also find that bone marrow from mouse models harboring known genetic mutations found in MDS (Asxl1-/-, Asxl1-/-Tet2-/-) display increased Rip1 kinase, suggesting that MDS genetic/epigenetic alterations result in increased necroptosis signaling that contributes to bone marrow cell death. Substantial data demonstrate that MDS is a clonal stem cell disorder(Graubert et al., 2012; Walter et al., 2011; Walter et al., 2012; Walter et al., 2013). A paradox inherent in MDS is that although the MDS-propagating clone has increased competitive ability, its expansion ultimately results in bone marrow failure. The presence of MDS stem cells and dying progenitor cells confers decreased function to the coexisting normal stem cells, suggesting that MDS stem and progenitor cells create a bone marrow environment that is killing normal hematopoietic stem cells. In our mouse model with unrestrained hematopoietic necrosis, mice die of bone marrow failure with the majority of the features of human MDS. Furthermore, bone marrow from these mice displayed increased competitive repopulating ability against wild type bone marrow, but transplanted mice die of bone marrow failure at four months despite the persistence of wild type bone marrow, suggesting that these necrotic HSC and progenitor cells can kill wild type HSCs to cause bone marrow failure. Our mice thus shed light on how an MDS clone can cause bone marrow failure: Our overarching hypothesis is that programmed necrosis in MDS cells triggers an inflammatory response that kills normal hematopoietic stem cells. This in term enables mutant stem and progenitor cells to expand and take over the bone marrow, thus driving bone marrow failure. Interrupting the cell death signaling pathway or altering the inflammatory signaling pathway has the potential to prevent cell death and re establish bone marrow homeostasis for therapeutic benefit. Aim 1: Will evaluate cell death and cytokine signaling in genetic mouse models of unrestrained necroptosis, as well as MDS mutations, to identify the molecular decision drivers, and how these drivers alter bone marrow cell death Aim 2: Will determine whether inhibiting necrosis or inflammatory signaling in HSC and progenitor cells in the above mouse models by inhibiting necrosis signaling (Rip1/Rip3 inhibitors) or inhibiting inflammatory signaling (Jak1/2 inhibitors) can reset hematopoietic homeostasis and prevent MDS bone marrow failure. Impact: The goal is to identify how HSCs and progenitor cells harboring MDS mutations execute cell death, and how they kill normal HSCs, and determine whether interrupting this cell death can rescue bone marrow function.

正常的造血需要严格控制新细胞的产生（增殖）并去除衰老 或受损的细胞（编程细胞死亡）。患有骨髓衰竭障碍的患者，例如 骨髓增生综合征（MDS）的骨髓编程细胞死亡增加，水平升高 诱导死亡的细胞因子，例如TNFA。过去几年的发现表明 除凋亡外，TNFA还激活了一种新型的细胞死亡形式，即编程坏死。凋亡细胞 在caspase驱动和免疫静音过程中内爆，而坏死细胞在RIP激酶驱动中爆炸 过程，释放细胞含量（潮湿）并引起免疫反应。我们发现RIP1增加了 70％的MDS患者样品中的激酶表达表明在MDS中激活了坏死性。我们 还发现，来自MDS中发现已知遗传突变的小鼠模型的骨髓（ASXL1 - / - ，， ASXL1 - / - TET2 - / - ）显示RIP1激酶增加，表明MDS遗传/表观遗传改变导致 坏死信号的增加，导致骨髓细胞死亡。大量数据表明 MDS是一种克隆干细胞疾病（Graubert等，2012; Walter等，2011; Walter等，2012; Walter等，， 2013）。 MDS固有的悖论是，尽管MDS传播克隆的竞争性提高了 能力，其扩张最终导致骨髓衰竭。 MDS干细胞的存在和死亡 祖细胞赋予对共存的正常干细胞的功能降低，表明MDS茎和 祖细胞会产生骨髓环境，该环境正在杀死正常的造血干细胞。在我们的 小鼠模型具有不受限制的造血坏死，大多数小鼠死于骨髓衰竭 人类MD的特征。此外，这些小鼠的骨髓表现出竞争力增加 对针对野生型骨髓的重新流动能力，但移植的小鼠死于四个骨髓衰竭 尽管野生型骨髓持续存在，但表明这些坏死的HSC和祖先 细胞可以杀死野生型HSC以引起骨髓衰竭。因此，我们的老鼠阐明了MDS克隆如何 导致骨髓衰竭：我们的总体假设是MDS细胞中编程的坏死会触发 炎症反应杀死正常的造血干细胞。在术语中，这使突变词干和 祖细胞扩展并接管骨髓，从而驱动骨髓衰竭。打断 细胞死亡信号通路或改变炎症信号通路具有预防细胞的潜力 死亡并重新建立骨髓稳态以获得治疗益处。目标1：将评估细胞死亡和 无节性坏死性和MDS突变的遗传小鼠模型中的细胞因子信号传导，以鉴定 分子决策驱动因素以及这些驱动因素如何改变骨髓细胞死亡目标2：将确定 在上述小鼠模型中，HSC和祖细胞中抑制坏死或炎症信号传导 通过抑制坏死信号传导（RIP1/RIP3抑制剂）或抑制炎症信号传导（JAK1/2抑制剂）可以 重置造血稳态并防止MDS骨髓衰竭。影响：目标是确定如何 HSC和携带MDS突变的祖细胞执行细胞死亡，以及它们如何杀死正常的HSC，并且 确定中断该细胞死亡是否可以挽救骨髓功能。