Hemangioblast Transplantation for Reconstitution of Lung Endothelium

描述(申请人提供)：来自骨髓的循环内皮祖细胞(EPC)已被证明有助于肿瘤血管生成和缺血肢体血管重建，然而，骨髓来源的细胞对肺内皮细胞的贡献尚不清楚。这项建议提供的初步数据表明，骨髓来源的细胞对肺血管内皮细胞有贡献，这些细胞来自具有血管母细胞潜能的多能造血干细胞(HSC)。这一观察表明，通过替换受损的内皮细胞或通过移植细胞携带的治疗性基因，增强这一过程可适用于涉及肺血管系统的疾病的治疗。然而，为了开发一种基于细胞的肺血管疾病的治疗方法，首先必须了解：a)骨髓来源的细胞在肺血管修复中的确切作用；b)血管重建细胞是否可以在肺损伤后直接输送来拯救受损的宿主；以及c)是否可以开发出增强内皮细胞植入的方法。这项赠款提案的具体目的是为了研究骨髓HSCs在重建肺内皮细胞中的作用。高氧暴露可造成小鼠肺内皮细胞的弥漫性损伤。在创伤后两周的恢复期内，研究了骨髓来源的细胞与天然内皮细胞对修复的内皮细胞的相对贡献，采用单细胞移植的方法，以确定负责内皮重建的干细胞的多能性和克隆性，最后，通过增加骨髓来源的细胞在受损肺内皮细胞的植入，开发了一种基于细胞的肺血管疾病治疗方法。促进干细胞自我更新分裂的基因的过度表达被用来在培养中扩大HSCs，这些细胞可以在肺损伤后注入小鼠体内。最后，细胞因子信号的操纵被用来动员和招募骨髓来源的细胞用于肺内皮细胞修复。这些具体目标的成功完成将有助于推进以细胞为基础的肺部疾病治疗研究，这些疾病涉及肺血管系统的损伤或病理。项目叙事。肺血管损伤是导致相当大的发病率和死亡率的原因，这些血管的异常或不完全修复是诸如肺高压和急性呼吸窘迫综合征等疾病的特征。这项建议开发了基于注射造血干细胞的新疗法，以挽救和修复这些受损肺血管的衬里细胞(内皮)。

DESCRIPTION (provided by applicant): Circulating endothelial progenitor cells (EPCs) derived from the bone marrow have been documented to contribute to tumor angiogenesis and ischemic limb revascularization, however, the contribution of marrow-derived cells to the pulmonary endothelium remains unclear. This proposal presents preliminary data showing that bone marrow-derived cells contribute to the pulmonary vascular endothelium, and that these cells arise from a pluripotent hematopoietic stem cell (HSC) with hemangioblastic potential. This observation suggests that enhancing this process could be adapted for the treatment of diseases involving the pulmonary vasculature by replacing damaged endothelial cells or by delivering therapeutic genes carried by engrafting cells. In order to develop a cell-based therapy for pulmonary vascular diseases, however, it is first crucial to understand: a) the precise role of bone marrow-derived cells in lung vascular repair; b) whether vascular reconstituting cells can be delivered directly after lung injury to rescue the injured host, and c) whether methods can be developed to augment endothelial engraftment. The specific aims of this grant proposal are designed to examine the roles of bone marrow HSCs in reconstituting the lung endothelium. Exposure to hyperoxia is employed to diffusely injure the lung endothelium of mice. During a two week recovery period after injury, the relative contributions of bone marrow-derived cells vs. native endothelial cells to the recovering endothelium is studied, Single cell transplantation is employed in order to confirm pluripotency and clonogenicity of the stem cells responsible for endothelial reconstitution, Finally, a cell-based therapy for pulmonary vascular diseases is developed through several approaches designed to augment the engraftment of bone marrow-derived cells in the injured lung endothelium. Over-expression of genes that promote self-renewing divisions of stem cells is used to expand HSCs in culture that can be infused into mice after lung injury. Finally, manipulation of cytokine signaling is used to mobilize and recruit bone marrow-derived cells for lung endothelial repair. Successful completion of the specific aims should help to advance research focused on cell-based therapies for lung diseases that involve injury or pathology of the pulmonary vasculature. PROJECT NARRATIVE. Injury to the blood vessels of the lung is responsible for considerable morbidity and mortality, and aberrant or incomplete repair of these vessels is characteristic of diseases such as pulmonary hypertension and acute respiratory distress syndrome. This proposal develops novel therapies, based on injections of hematopoietic stem cells, in order to rescue and repair the lining cells (endothelium) of these injured lung vessels.