ATHEROSCLEROTIC LESION INITIATION BY RESIDENT AORTIC MACROPHAGE PROLIFERATION AND LIPID UPTAKE

项目摘要/摘要 心血管疾病是美国发病率和死亡率的主要原因。 动脉粥样硬化是一种大中型动脉的炎症性疾病，促进血管的发展。 通过斑块形成、血流受限，最终导致血栓形成，从而导致心血管疾病的发生。 动脉内皮细胞长期暴露于升高的(和可能改变的)血清胆固醇会导致 病理特征；包括血流模式改变，内皮细胞激活，以及 血单核细胞。浸润性单核细胞分化为脂质斑块巨噬细胞，并有助于 坏死核心是晚期病变的标志。研究的重点是单核细胞在体内的作用。 然而，动脉粥样硬化斑块的维护；专门用于研究的资源相对较少 驻留在主动脉弓中的组织驻留的单核巨噬细胞(MNP)的作用。常驻MNPs 出生时居住在新生主动脉中，在斑块容易发展的位置，细胞是 甚至存在于不易感染疾病的动物体内。我的初步研究明确显示这些细胞 巨噬细胞系细胞，而不是先前报道的树突状细胞，可能促进早期 通过将第一个定量的胆固醇负荷引入到血管内膜中，来控制斑块的形成。因此，这些细胞可能在 调节动脉粥样硬化斑块负荷。然而，确定内膜是否存在的技术方法 巨噬细胞在斑块中持续存在并发挥不同的作用尚未出现来解决这种可能性。 我已经建立了跟踪和调节常驻内膜巨噬细胞数量的方案 不依赖于单核细胞等渗入的血源性前体细胞。我发现常驻巨噬细胞是 首先，细胞在主动脉壁中吸收脂肪，并在斑块形成过程中持续存在。常驻巨噬细胞 居住在已知会发展成坏死核的区域内，并在斑块本身周围形成一个“边界”。 此外，我还开发了跟踪斑块内巨噬细胞增殖的方法，以及使用 分离内膜巨噬细胞而不污染单核细胞或外膜的新技术 巨噬细胞。主要使用固定成像和活体成像相结合的方法治疗小鼠动脉粥样硬化 斑块和利用新的小鼠模型，我将测试驻留的主动脉内膜的假设 巨噬细胞，独立于招募的单核细胞来源的巨噬细胞，发挥着独特而重要的作用 在动脉粥样硬化斑块形成中的作用。为了验证我的假设，我将评估核扩散和 斑块中的运动性，解决驻留和招募的单核细胞在疾病中的不同作用 进展，并进一步发展活体内方法，以了解单核细胞和 内膜巨噬细胞可能与疾病的严重程度有关。如果是真的，这项研究的影响将极大地 阐明和改变磁场可能以巨噬细胞或循环单核细胞为靶点来管理动脉粥样硬化的方式 疾病。

Project Summary/Abstract Cardiovascular disease is a leading cause of morbidity and mortality in the United States. Atherosclerosis is an inflammatory disease of the large and mid-sized arteries that promotes the development of cardiovascular disease through plaque formation, restricted blood flow, and ultimately thrombotic events. Chronic exposure of the arterial endothelium to elevated (and potentially modified) serum cholesterol leads to the hallmarks of pathology; including altered blood flow patterns, endothelial activation, and recruitment of blood monocytes. Infiltrating monocytes differentiate into lipid-laden plaque macrophages and contribute to the necrotic core that is a hallmark of advanced lesions. Research has focused on the role of monocytes in the maintenance of atherosclerotic plaques however; relatively few resources have been dedicated to investigating the role of tissue-resident mononuclear phagocytes (MNPs), which reside in the aortic arch. Resident MNPs reside in the nascent aorta at birth in locations where plaques have propensity to develop, and the cells are even present there in animals not susceptible to disease. My preliminary studies definitively show these cells are macrophage lineage cells, not dendritic cells as previously reported and may facilitate the onset of early plaque by importing the first quantitative load of cholesterol into the intima. Thus, these cells may be pivotal in regulating atherosclerotic plaque burden. However, technical approaches to determine if intimal resident macrophages persist in plaques and carry out distinct roles have not emerged to address this possibility. I have established protocols to track and modulate the resident intimal macrophage population independent of infiltrating blood-derived precursors like monocytes. I find that resident macrophages are the first cells to take up lipid in the aortic wall and persist through plaque development. Resident macrophages reside inside regions known to develop into necrotic core, and also form a “boarder” around the plaque itself. Further, I have developed approaches to track proliferation of macrophages within the plaque, as well as use new technologies to isolate intimal macrophages without contamination from monocytes or adventitial macrophages. Primarily using a combination of fixed- and live-imaging approaches in murine atherosclerotic plaque and taking advantage of new mouse models, I will test the hypothesis that resident aortic intimal macrophages, independent of recruited monocyte-derived macrophages, play a unique and important role in atherosclerotic plaque development. To test my hypothesis, I will assess the role of proliferation and motility in the plaques, address the differential roles of resident versus recruited monocytes in disease progression, and further develop intravital approaches to understand how interactions between monocytes and intimal macrophages may contribute to disease severity. If true, the implications of this study would greatly clarify and alter how the field might target macrophages or circulating monocytes to manage atherosclerotic disease.