The Role of Nitric Oxide Synthase in Circulating Progenitor Cell Function

描述（由申请人提供）：我们建议确定内皮一氧化氮合酶（eNOS）在人内皮祖细胞（EPCs）年龄或疾病相关功能障碍中的作用。衰老或累积不同心血管危险因素的一个后果是血管内皮功能的下降。这似乎与体外测量的EPC功能下降有关。EPCs在动物和人类中的移植已经被认为可以增强心肌梗死或外周缺血后的功能性组织保存/再生，这可能得到我们自己的初步研究的支持。然而，EPC功能已被证明可以决定组织恢复的程度。心肌梗死后移植EPCs后，培养中EPCs功能下降与EPCs帮助组织再生的能力下降有关。这就提出了一个问题，即如果EPCs本身功能受损，则患者自身EPCs的体外扩增和再输注可能无效。该建议的主要假设是，在一些心血管高危人群中，由于eNOS依赖性一氧化氮（NO）产生减少，EPC功能受损，功能失调的EPCs可以通过工程设计使其过表达eNOS来增强功能。具体目的是(1)评估来自心血管疾病高风险和低风险人群（包括年龄）的EPCs中EPC功能与eNOS依赖性NO产生之间是否存在相关性，(2)评估工程EPCs过度表达eNOS是否增强其改善心血管疾病啮鼠模型功能的能力，以及(3)研究NO在EPC功能中的机制作用。相关性：在血液中循环的祖细胞被认为参与血管的生长和维持。来自老年人或患有某些心血管疾病的人的祖细胞比来自健康年轻人的祖细胞功能更差。这项研究将确定eNOS酶的缺乏是否部分导致了这一问题，并将探索基因工程这种祖细胞的可能性，以改善它们的功能，从而增加它们的有益作用。

DESCRIPTION (provided by applicant): We propose to determine the role of endothelial nitric oxide synthase (eNOS) in age- or disease-related dysfunction of human endothelial progenitor cells (EPCs). One consequence of aging or accumulating different cardiovascular risk factors is a decrease in the functional capabilities of the vascular endothelium. This appears to correlate with a decrease in EPC function as measured ex vivo. Transplantation of EPCs in both animals and humans has been suggested to enhance functional tissue preservation/regeneration after myocardial infarction or peripheral ischemia, a possibly that is supported by our own preliminary studies. However, EPC function has been shown to determine the extent of tissue recovery. Decreased EPC function in culture is associated with decreased ability of EPCs to aid in tissue regeneration when transplanted after myocardial infarction. This presents the problem that ex vivo expansion and re-infusion of a patient's own EPCs may be ineffective if the EPCs themselves are functionally impaired. The main hypothesis of this proposal is that EPC function is impaired in some populations with high cardiovascular risk as a result of reduced eNOS-dependent nitric oxide (NO) production, and that dysfunctional EPCs can be functionally enhanced by engineering them to overexpress eNOS. The specific aims are (1) to evaluate whether a correlation exists between EPC function and eNOS-dependent NO production in EPCs from populations with high versus low cardiovascular risk, including age, (2) to assess whether engineering EPCs to overexpress eNOS enhances their ability to improve function in rodent models of cardiovascular disease, and (3) to examine the mechanistic role of NO in EPC function. RELEVANCE: Progenitor cells that circulate in the blood are thought to participate in the growth and maintenance of blood vessels. Such progenitor cells from elderly individuals, or people who suffer from certain cardiovascular maladies, are less able to function than those from healthy young individuals. This research will determine if a deficiency in the enzyme eNOS is partially responsible for this problem, and will also explore the possibility of genetically engineering such progenitor cells to improve their function, thereby increasing their beneficial effects.