Mechanisms of foamy monocyte formation in atherosclerosis

动脉粥样硬化中泡沫单核细胞形成的机制

• 批准号: 10707022
• 负责人: WonMo Ahn
• 金额: $ 4.77万
• 依托单位: AUGUSTA UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2022
• 资助国家: 美国
• 起止时间: 2022-08-17 至 2025-08-16
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/10707022
• 关键词: Academic Training; Adhesions; Affinity; Arteries; Atherosclerosis; Attenuated; Biology; Blood Vessels; CD36 gene; Cardiovascular system; Cause of Death; Chemical Stimulation; Chemicals; Consensus; Data; Development; Endothelium; FDA approved; Foam Cells; Funding; Genetic; Goals; Health; Human; In Vitro; Inflammatory; Ischemic Stroke; Knockout Mice; Lipids; Liquid substance; Low-Density Lipoproteins; Macrophage; Mediating; Membrane; Mentorship; Methodology; Mus; Myeloid Cells; Myocardial Infarction; NHE1; Pathogenesis; Pathway interactions; Patients; Peripheral arterial disease; Pharmaceutical Preparations; Phase; Phenotype; Physiological; Plasma; Play; Pre-Clinical Model; Process; Publishing; Recording of previous events; Research; Role; Secure; Stroke; Technical Expertise; Testing; Tetradecanoylphorbol Acetate; Time; Training; United States; Universities; Woman; cost; cytokine; health care delivery; hypercholesterolemia; improved; in vivo; inflammatory marker; inhibitor; insight; medical schools; men; migration; monocyte; new therapeutic target; novel; pharmacologic; post-doctoral training; pre-doctoral; receptor; receptor mediated endocytosis; scavenger receptor; skills; therapeutic target; therapeutically effective; uptake

PROJECT SUMMARY Atherosclerosis, the underlying cause of heart attack, stroke and peripheral arterial disease, is the leading cause of death in the United States. A better understanding of the pathomechanisms of atherosclerosis is critical to identify more effective therapeutic strategies to treat atherosclerosis. Recent studies demonstrated that majority of the circulating monocyte pool in patients with atherosclerosis are lipid-laden foamy monocytes and pharmacological depletion of foamy monocytes in hypercholesterolemic mice attenuates atherosclerosis development. Although these studies suggest that monocyte uptake of plasma LDL is a therapeutic target in atherosclerosis, the mechanism of foamy monocyte formation is currently unknown. Preliminary studies demonstrate for the first time that chemical stimulation of macropinocytosis promotes native LDL uptake, leading to foamy monocyte formation in vitro. Moreover, pharmacological inhibition of macropinocytosis and genetic deletion of the macropinocytosis regulator, NHE1, selectively in myeloid cells attenuates atherosclerosis development in hypercholesterolemic mice. The central hypothesis of this proposal is that stimulation of macropinocytosis promotes monocyte lipid uptake and foamy monocyte formation. Aim 1 will test the hypothesis that physiologically relevant stimulators of macropinocytosis increase foamy monocyte formation in vitro. We will assess the ability of human primary and THP1 monocytes to uptake lipids in the presence or absence of physiologically relevant macropinocytosis stimulators and pharmacological inhibitors. The relative contribution of scavenger receptor-mediated lipid uptake vs. macropinocytosis will be quantified using monocytes from wild type, CD36-/-, SRA-/- and CD36-/-/SRA-/- mice. Finally, we will assess phenotypic and functional changes in foamy monocytes relevant to the pathogenesis of atherosclerosis. Aim 2 will test the hypothesis that myeloid cell- specific deletion of the macropinocytosis regulator, NHE1, inhibits foamy monocyte formation in vivo. Monocytes from NHE1f/f Lysm Cre+ and littermate Cre- mice injected with AAV8-PCSK9 will be isolated and analyzed for lipid content, inflammatory cytokine secretion, inflammatory markers, and adhesion ability. Additionally, we will use wild type and CD36-/-/SRA-/- mice to assess the effect of a repurposed FDA-approved drug that inhibits macropinocytosis in attenuating circulating foamy monocyte levels. This project will allow me to develop new technical skills, gain expertise in conducting rigorous, hypothesis-driven research and improve my independent skills. The project will be conducted under the mentorship of Dr. Gabor Csanyi and Dr. Neal Weintraub in the Vascular Biology Center at the Medical College of Georgia, Augusta University, which has a rich history of successful pre- and post-doctoral training. The proposed project is for 3 years of funding with the aims divided amongst the 3 years of funding, culminating with a dissertation defense at the end of the third year. We anticipate that findings from this novel proposal will identify macropinocytosis as a key mechanism by which monocytes internalize lipids and will highlight this pathway as a new therapeutic target in atherosclerosis.

项目总结 动脉粥样硬化是心脏病发作、中风和外周动脉疾病的根本原因，是主要原因 在美国的死亡。更好地了解动脉粥样硬化的发病机制对于 确定更有效的治疗策略来治疗动脉粥样硬化。最近的研究表明，大多数人 动脉粥样硬化患者的循环单核细胞池中有富含脂质的泡沫单核细胞和 药物去除高胆固醇血症小鼠泡沫单核细胞可减轻动脉粥样硬化 发展。尽管这些研究表明单核细胞摄取血浆低密度脂蛋白是一种治疗目标 动脉粥样硬化，单核细胞泡沫化的形成机制目前尚不清楚。初步研究 首次证明化学刺激巨噬细胞增多促进了天然低密度脂蛋白的摄取，导致 在体外形成单核细胞泡沫。此外，药物抑制巨噬细胞吞噬和遗传 髓系细胞中巨噬细胞吞噬调节因子NHE1的选择性缺失可减轻动脉粥样硬化 高胆固醇血症小鼠的发育。这一提议的中心假设是，刺激 巨噬细胞吞噬促进单核细胞脂质摄取和泡沫单核细胞的形成。目标1将检验这一假设 巨噬细胞增多的生理相关刺激物在体外增加泡沫单核细胞的形成。我们会 评估人原代单核细胞和THP1单核细胞在存在或不存在的情况下摄取脂质的能力 生理上相关的巨噬细胞吞噬激动剂和药理抑制药。相对贡献 清道夫受体介导的脂质摄取与巨噬细胞吞噬作用的对比将使用野生单核细胞进行量化 CD36-/-、SRA-/-和CD36-/-/SRA-/-小鼠。最后，我们将评估泡沫的表型和功能变化。 单核细胞与动脉粥样硬化的发病机制有关。目标2将测试髓系细胞- 巨噬细胞吞噬调节因子NHE1的特异性缺失可抑制体内泡沫单核细胞的形成。单核细胞 从注射AAV8-PCSK9的NHE1f/f Lysm Cre+和产仔Cre-小鼠中分离并分析脂质 内容物、炎性细胞因子分泌、炎性标志物、黏附能力。此外，我们将使用 野生型和CD36-/-/SRA-/-小鼠评估FDA批准的一种改变用途的抑制药物的效果 巨噬细胞吞噬降低循环泡沫单核细胞水平。这个项目将使我能够开发新的 技术技能，在进行严谨的、假设驱动的研究方面获得专业知识，并提高我的独立性 技能。该项目将在Gabor Csanyi博士和Neal Wetraub博士的指导下进行 奥古斯塔大学佐治亚州医学院血管生物学中心，拥有丰富的 成功开展博士后和博士后培训。建议的项目为期3年，资助目标各不相同。 在三年的资助中，最终在第三年结束时进行了论文答辩。我们期待着 这一新提议的发现将确定巨噬细胞增多是单核细胞 内化脂质，并将突出这一途径作为动脉粥样硬化的新治疗靶点。