Biomechanical Determinants of Hematopoietic Stem Cell Potential

项目总结 几十年来，异基因造血干细胞(HSC)移植的临床结果一直是 受供者匹配的造血干细胞来源的限制。这推动了全球捐赠者状况的改善 招募和匹配，以及积极追求新的战略，以发展患者衍生的或 普遍相容的造血细胞。指定人类造血干细胞的尝试只产生了祖细胞 具有有限的谱系和植入潜力，使用共培养和通过 修饰的RNA或病毒整合。 我们的研究表明，血液流经血管系统所产生的生物机械力是一个关键的调节因素。 能促进具有长期造血重建潜力的细胞的植入。一个 在成人血管内皮细胞中，许多特征明确的通路被流体切应力激活，但 关于血源性内皮细胞及其前体细胞在胚胎发生中的信号转导知之甚少。我们的 初步数据强烈表明血流的启动是能量代谢的关键决定因素 HSC前体细胞中的线粒体动力学称为血源性内皮细胞。 我们研究的目的是定义由生物机械力触发的信号机制 明确的造血，长期目标是利用生物物理线索，如定向的剪应力 用于治疗性移植和血液疾病建模的定制造血干细胞的分化和扩展。 具体地说，我们的目标是确定由促进血管扩张的血管力量诱导的线粒体适应 通过利用报告小鼠的HSC出现和线粒体动力学模型来研究血源性内皮。 我们将确定线粒体特征，这些特征有助于具有HSC潜能的细胞的命运选择和生存 使用小鼠胚胎和多潜能干细胞的分化培养。我们将审问并定义 细胞内信号驱动线粒体重塑对生理强度的流体力的响应 药物和基因靶向的血源性内皮细胞。此外，中断或 增强的线粒体能力将在造血性内皮细胞命运选择和进入 成年后揭示线粒体动力学如何在体内最早阶段影响造血程序 血管系统。拟议的研究有望填补我们对新指定的造血干细胞如何认识的一个主要空白。 它们的前体产生能量并管理新陈代谢过程，并将为研究新的 通过代谢调控构建竞争性自我更新的造血干细胞的方法。

PROJECT SUMMARY For several decades, clinical outcomes of allogeneic hematopoietic stem cell (HSC) transplantation have been limited by the availability of donor-matched sources of HSCs. This has motivated global improvements in donor recruitment and matching, as well as aggressive pursuit of new strategies for development of patient-derived or universally compatible hematopoietic cells. Attempts to specify human HSCs have only produced progenitors with limited lineage and engraftment potential using co-culture and expression of hematopoietic genes through modified RNAs or viral integration. Our studies show that biomechanical force caused by flow of blood through the vasculature is a critical regulator of hematopoiesis and can promote engraftment of cells with long-term hematopoietic reconstitution potential. A number of well-characterized pathways are activated by fluid shear stress in adult vascular endothelial cells, yet little is known about signaling within hemogenic endothelial cells and their precursors in embryogenesis. Our preliminary data strongly implicates initiation of blood flow as a critical determinant of energy metabolism and mitochondrial dynamics in the HSC precursor known as the hemogenic endothelium. The objective of our research is to define signaling mechanisms triggered by biomechanical force that promote definitive hematopoiesis, with the long-term goal of exploiting biophysical cues such as shear stress in directed differentiation and expansion of customized HSCs for therapeutic transplant and blood disease modeling. Specifically, we aim to identify mitochondrial adaptations induced by vascular force that promote expansion of hemogenic endothelium via utilization of reporter mouse models of HSC emergence and mitochondrial dynamics. We will identify mitochondrial features that contribute to fate selection and survival of cells with HSC potential using murine embryos and differentiation cultures of pluripotent stem cells. We will interrogate and define the intracellular signaling that drives mitochondrial remodeling in response to physiologic intensities of fluid force in hemogenic endothelium by pharmacological and genetic targeting. Further, consequences of disrupted or enhanced mitochondrial capacity will be defined during hemogenic endothelial cell fate selection and into adulthood to reveal how mitochondrial dynamics impact the hematopoietic program at its earliest stages within the vasculature. The proposed study promises to fill a major gap in our knowledge of how newly specified HSCs and their precursors produce energy and manage metabolic processes, and will provide insight into novel methods for engineering competitive self-renewing HSCs through manipulation of metabolism.