Hemangioblast Transplantation for Reconstitution of Lung Endothelium

描述（由申请方提供）：已证实来源于骨髓的循环内皮祖细胞（EPC）有助于肿瘤血管生成和缺血性肢体血运重建，然而，骨髓来源的细胞对肺内皮的作用尚不清楚。该提案提出的初步数据显示，骨髓来源的细胞有助于肺血管内皮，并且这些细胞来自具有成血管细胞潜能的多能造血干细胞（HSC）。这一观察结果表明，通过替换受损的内皮细胞或通过递送移植细胞携带的治疗基因，增强这一过程可适用于治疗涉及肺血管系统的疾病。然而，为了开发用于肺血管疾病的基于细胞的疗法，首先关键的是理解：a）骨髓来源的细胞在肺血管修复中的确切作用; B）是否可以在肺损伤后直接递送血管重建细胞以拯救受损的宿主，以及c）是否可以开发增加内皮移植的方法。该拨款提案的具体目标旨在研究骨髓HSC在重建肺内皮中的作用。采用高氧暴露方法对小鼠肺内皮细胞造成弥漫性损伤。在损伤后两周的恢复期期间，研究了骨髓来源的细胞与天然内皮细胞对恢复内皮的相对贡献。采用单细胞移植以确认负责内皮重建的干细胞的多能性和克隆原性。最后，肺血管疾病的基于细胞的疗法是通过几种设计用于增加骨髓植入的方法开发的，损伤的肺内皮细胞中的衍生细胞。促进干细胞自我更新分裂的基因的过表达用于在培养物中扩增HSC，所述培养物可以在肺损伤后输注到小鼠中。最后，操纵细胞因子信号传导用于动员和募集骨髓来源的细胞用于肺内皮修复。这些具体目标的成功实现将有助于推进针对涉及肺血管损伤或病理的肺部疾病的基于细胞的疗法的研究。项目叙述。肺血管的损伤导致相当大的发病率和死亡率，并且这些血管的异常或不完全修复是诸如肺动脉高压和急性呼吸窘迫综合征的疾病的特征。该提案开发了基于注射造血干细胞的新疗法，以拯救和修复这些受损肺血管的衬里细胞（内皮细胞）。

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.