Selective Radionuclide Delivery for Precise Bone Marrow Niche Alterations

项目摘要/摘要 骨髓壁龛中有造血干细胞(HSCs)，这种细胞可以自我更新并分化为 血液成分，如白细胞、红细胞和血小板。造血干细胞受到其他骨髓的支持 驻留细胞，如血管内皮细胞和基质细胞，为骨髓提供必要的信号。 不幸的是，用于治疗癌症患者的放射和/或化疗会损害骨髓生态位。 骨髓功能受损使患者面临低血细胞计数的潜在致命风险。因为鲜血 癌症对辐射、通过放射免疫疗法进行的靶向辐射传递或靶向-- 稳定地与放射性同位素相连的特定抗体已经被开发出来用于治疗血液系统恶性肿瘤， 尽管有些人的骨髓恢复缓慢。尽管不断增加的临床试验评估 放射免疫疗法，这些释放的放射性核素如何影响细胞、分子和系统 调节骨髓生态位的机制尚未确定。放射免疫治疗的影响 如果放射免疫疗法要获得牵引力，就必须解决骨髓利基的问题，并具体说明 这些机制可以被用来将辐射引起的骨髓毒性降至最低。使问题进一步复杂化 放射免疫治疗的效用，放射性核素具有不同的有效载荷特征，后果未知 在骨髓壁龛上。这项提议将揭示阿尔法发射器(Astatine-211)的不同影响。 和贝塔发射体(Y-90)与非靶向X射线辐射进行比较，以获得必要的知识 在临床上推进这些技术的发展。我们将报告这些辐射类型是如何不同地调节 造血干细胞、内皮细胞和基质细胞的丰度和功能，它们是血液系统功能的基本调节细胞。我们 还将通过比较辐射靶向如何影响骨髓成分来比较 使用广泛的血液学标志物(CD45)和更受限的表面标志物(CD33)进行放射免疫治疗 会影响骨髓成分。在实验上，我们将在小鼠身上使用体内竞争性移植试验 评估长期和短期的HSC潜能作为放射免疫治疗的功能。这些研究将是 结合流式细胞术量化辐射类型如何调节造血细胞、血管细胞和基质细胞 频率、死亡和增殖。我们将利用尖端共聚焦成像技术和厚股骨切片来 了解放射免疫疗法如何以不同的方式调节三维骨髓结构， 对血管壁龛功能和血液学的辐射恢复至关重要。更重要的是，差异基因 不同放射性核素对肝星状细胞、内皮细胞和基质细胞的表达 也将使用RNA序列分析来量化。这些实验的结果表明 确定导致HSCs辐射损伤的机制以及内皮细胞和基质细胞的反应 可以操纵的系统，以获得所需的临床结果，并为提供商提供加速的工具 在骨髓干细胞移植中，骨髓恢复或抑制残留的造血功能。

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.