Selective Radionuclide Delivery for Precise Bone Marrow Niche Alterations

项目总结/摘要 骨髓龛容纳造血干细胞（HSC），这些细胞可以自我更新并分化为重要的造血干细胞。 血液成分如白色血细胞、红细胞和血小板。造血干细胞由其他骨髓支持 常驻细胞，如血管内皮细胞和基质细胞，用基本信号滋养骨髓。 不幸的是，用于治疗癌症患者的放疗和/或化疗会损伤骨髓小生境。 受损的骨髓功能使患者处于低血细胞计数的潜在致命风险中。因为血液 癌症对辐射、通过放射免疫疗法的靶向辐射递送或靶向- 与放射性同位素稳定连接的特异性抗体已经被开发用于治疗血液恶性肿瘤， 尽管有些人骨髓恢复缓慢。尽管越来越多的临床试验评估 放射免疫疗法，这些递送的放射性核素如何影响细胞，分子和全身 调节骨髓生态位的机制还有待确定。放射免疫治疗的影响 如果放射免疫疗法要获得牵引力，就必须解决骨髓龛的问题， 这些机制可用于最大限度地减少辐射诱导的骨髓毒性。进一步复杂化 放射免疫治疗的效用，放射性核素具有不同的有效载荷特性，后果未知 在骨髓龛上这项提议将揭示α-发射体（<$211）的差异效应 和β-发射体（钇-90）与非靶向X射线辐射的比较，以获得基本知识， 将这些技术应用于临床。我们将报告这些辐射类型如何差异调节 HSC、内皮细胞和基质细胞的丰度和功能，血液功能的基本调节剂。我们 还将比较辐射靶向如何影响骨髓成分， 使用广泛的血液学标志物（CD 45）和更严格的表面标志物（CD 33）的放射免疫治疗 影响骨髓成分。在实验上，我们将使用小鼠体内竞争性移植试验 评估长期和短期HSC潜力作为放射免疫治疗的功能。这些研究报告将 再加上流式细胞术，以量化辐射类型如何调节造血，血管和基质细胞 频率、死亡和扩散。我们将利用最先进的共焦成像技术， 了解放射免疫疗法如何差异调节三维骨髓结构， 对于血管生态位功能和辐射后血液学恢复至关重要。更重要的是，差异基因 在HSC、内皮细胞和基质细胞区室中表达，作为对不同放射性核素的反应 还将使用RNA序列分析来定量递送。这些实验的结果表明， 确定HSC辐射损伤的机制，以及内皮细胞和基质细胞的反应 系统可以被操纵，以获得所需的临床结果，并为提供者提供工具， 骨髓恢复或抑制骨髓干细胞移植中所需的残余造血。

PROJECT SUMMARY / ABSTRACT The bone marrow niche houses hematopoietic stem cells (HSCs), cells that self-renew and differentiate into vital blood components like white blood cells, red blood cells, and platelets. HSCs are supported by other marrow resident cells, like vascular endothelial cells and stromal cells, that nourish the marrow with essential signals. Unfortunately, radiation and/or chemotherapy used to treat cancer patients injure the bone marrow niche. Damaged bone marrow function places patients at potentially fatal risks from low blood counts. Because blood cancers are exquisitely sensitive to radiation, targeted radiation delivery via radioimmunotherapy, or target- specific antibodies stably linked to radioactive isotopes, has been developed to treat hematologic malignancies, though some have with slow bone marrow recovery. Despite increasing clinical trials evaluating radioimmunotherapies, how these delivered radionuclides impact the cellular, molecular, and systemic mechanisms that regulate the bone marrow niche has yet to be identified. The impact of radioimmunotherapy on the bone marrow niche must be addressed if radioimmunotherapies are to gain traction, and specifics on these mechanisms can be leveraged to minimize radiation-induced marrow toxicity. Further complicating the utility of radioimmunotherapy, radionuclides have distinct payload characteristics with unknown consequences on the bone marrow niche. This proposal will uncover the differential effects of an alpha-emitter (astatine-211) and a beta-emitter (yttrium-90) compared to non-targeted X-ray radiation to procure essential knowledge to advance these technologies clinically. We will report how these radiation types differentially regulate the abundance and function of HSCs, endothelial and stromal cells, essential regulators of hematologic function. We will also compare how radiation targeting impacts bone marrow components by comparing how radioimmunotherapy using a broad hematologic marker (CD45) and more restricted surface marker (CD33) impacts bone marrow components. Experimentally, we will use in vivo competitive transplantation assays in mice to assess long-term and short-term HSC potential as a function of radioimmunotherapy. These studies will be coupled with flow cytometry to quantify how radiation type regulates hematopoietic, vascular, and stromal cell frequency, death, and proliferation. We will leverage cutting-edge confocal imaging with thick femur sections to understand how radioimmunotherapy differentially regulates the three-dimensional bone marrow architecture, critical for vascular niche function and hematologic recovery from irradiation. More importantly, differential gene expression in the HSC, endothelial and stromal cell compartments, as a response to differential radionuclide delivery, will also be quantified using RNA sequence analyses. The results from these experiments stand to identify mechanisms responsible for radiation injury in HSCs, and the endothelial and stromal cell response systems that can be manipulated to derive a desired clinical outcome, and give providers the tools to accelerate bone marrow recovery, or inhibit residual hematopoiesis as desired in bone marrow stem cell transplantation.