Developmental Activation of the Inflammasome Controls Hematopoietic Stem Cell Production

摘要 造血干细胞(HSCs)为血液和免疫系统提供终身基础。肝星状细胞 是有治疗价值的，因为造血干细胞移植是许多血液病的标准护理。 然而，由于免疫不相容和供体短缺，治疗的可获得性仍然存在问题。 同样，虽然移植的造血干细胞的数量直接影响结果，但目前还没有确定的 成功扩增供者采集的造血干细胞的临床方案，也不能分化胚胎或诱导 多能干细胞(IPSCs)体外分化为有功能的HSCs。因此，De的新型修饰剂的鉴定 体外培养具有长期自我更新和分化能力的造血干细胞是目前临床上尚未满足的主要需求。 尽管经过了几十年的研究，目前的方案主要依赖于FORCE细胞的转录因子过度表达 移植到“类造血干细胞”计划中；然而，这些体外来源的造血干细胞移植只能产生有限的长期效果。 嫁接和多系潜力。这些观察表明，目前的体外分化 策略缺少关键信号，而这些信号是体内解锁或维持完整的HSC功能所必需的。 造血干细胞最初是在脊椎动物胚胎中由一组独特的中胚层前体形成的。 通过高度保守的血管内皮细胞向造血细胞转化的过程称为血源性内皮细胞 过渡。我们之前已经利用斑马鱼模型来发现HSC形成的新调节因子， 包括在FDA批准的临床试验中使用的第一种斑马鱼疗法。此外，我们 已经证明，在胚胎发育过程中发生的关键外部信号协调着 HSC生产。最近，我们的实验室揭示了炎症信号在发育过程中的重要作用 HSPC编队。然而，无菌炎症在胚胎中产生的机制还没有得到证实。 下定决心。我们的初步数据表明，胚胎发育过程中代谢状态的生理变化 启动无菌炎症信号以刺激HSC的承诺和扩张，而不会丧失多能性。 我们的中心假设是“发育应激源”，如新陈代谢活动的开始，激活了 NLRP3-炎症体驱动无菌的IL1β介导的对造血干细胞生产的承诺。我们建议的工作 将展示发育性炎性小体激活在建立HSPC承诺中的重要作用 斑马鱼胚胎体内扩增和人IPSC体外培养。分子信令的定义 体内介导产生HSC的途径将揭示优化定向的 用于治疗用途的人造血干细胞的扩增和/或从头生产。

SUMMARY Hematopoietic stem cells (HSCs) supply the lifelong foundation of the blood and immune systems. HSCs are therapeutically valuable as HSC transplantation is the standard of care for many hematological diseases. However, treatment availability remains problematic due to immune incompatibility and donor shortage. Likewise, while the number of transplanted HSCs directly impacts outcome, there are currently no established clinical protocols to successfully expand donor-harvested HSCs, nor to differentiate embryonic or induced pluripotent stem cells (iPSCs) into functional HSCs in vitro. Therefore, the identification of novel modifiers of de novo production of HSCs with long-term self-renewal and differentiation capacity is a major unmet clinical need. Despite decades of research, current protocols rely primarily on transcription factor overexpression of force cells into an “HSC-like” program; however, transplantation of these in vitro-derived HSCs yields only limited long-term engraftment and multilineage potential. These observations imply that current in vitro differentiation strategies are missing critical cues which are essential to unlock or maintain full HSC function in vivo. HSCs are first formed in the vertebrate embryo from a unique population of mesodermal precursors termed hemogenic endothelium through a highly conserved process known as endothelial-to-hematopoietic transition. We have previously utilized the zebrafish model to discover novel regulators of HSC formation, including the first therapeutic identified in zebrafish to be used in FDA-approved clinical trials. In addition, we have demonstrated that key extrinsic signals occurring during embryogenesis coordinate the timing and scale of HSC production. More recently, our lab revealed an essential role for inflammatory signaling in developmental HSPC formation. However, the mechanism by which sterile inflammation originates in the embryo has not been determined. Our preliminary data indicate that physiological changes in metabolic state during embryogenesis initiate sterile inflammatory signaling to stimulate HSC commitment and expansion, without loss of multi-potency. Our central hypothesis is that “developmental stressors”, such as onset of metabolic activity, activate the NLRP3-inflammasome to drive sterile IL1β-mediated commitment to HSC production. Our proposed work will demonstrate the essential role of developmental inflammasome activation in establishing HSPC commitment and expansion in vivo in zebrafish embryos and in vitro in human iPSC culture. Defining the molecular signaling pathways that mediate productive HSC formation in vivo will reveal new targets for optimizing the directed expansion and/or de novo production of human HSCs for therapeutic use.