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: 10537459
• 负责人: WonMo Ahn
• 金额: $ 4.68万
• 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/10537459
• 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; Mediating; Membrane; Mentorship; Methodology; Mus; Myeloid Cells; Myocardial Infarction; NHE1; Pathogenesis; Pathway interactions; Patients; Peripheral arterial disease; Pharmaceutical Preparations; Pharmacology; Phase; Phenotype; Physiological; Plasma; Play; Pre-Clinical Model; Process; Publishing; Recording of previous events; Research; Role; Secure; Stroke; Technical Expertise; Testing; Tetradecanoylphorbol Acetate; Time; United States; Universities; Woman; cost; cytokine; health care delivery; improved; in vivo; inflammatory marker; inhibitor; insight; macrophage; medical schools; men; monocyte; new therapeutic target; novel; 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.

项目摘要 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， 死亡在美国。更好地理解动脉粥样硬化的病理机制对于 确定更有效的治疗动脉粥样硬化的治疗策略。最近的研究表明，大多数 动脉粥样硬化患者的循环单核细胞池中的20%是载脂泡沫状单核细胞， 高胆固醇血症小鼠泡沫单核细胞的药理学清除减轻动脉粥样硬化 发展尽管这些研究表明单核细胞对血浆LDL的摄取是一个治疗靶点， 在动脉粥样硬化中，泡沫单核细胞形成的机制目前尚不清楚。初步研究 首次证明了巨胞饮作用的化学刺激促进了天然LDL的摄取， 泡沫状单核细胞的体外形成。此外，大胞饮和遗传的药理学抑制 髓样细胞中选择性缺失巨胞饮调节因子NHE 1可减轻动脉粥样硬化 在高胆固醇血症小鼠中的发展。这一建议的核心假设是， 巨胞饮作用促进单核细胞脂质摄取和泡沫状单核细胞形成。目标1将检验假设 生理上相关的巨胞饮刺激物在体外增加泡沫单核细胞的形成。我们将 评估人原代单核细胞和THP 1单核细胞在存在或不存在以下物质的情况下摄取脂质的能力 生理学相关的巨胞饮刺激剂和药理学抑制剂。的相对贡献 清道夫受体介导的脂质摄取与巨胞饮作用的关系将使用来自野生型的单核细胞进行定量。 型、CD 36-/-、SRA-/-和CD 36-/-/SRA-/-小鼠。最后，我们将评估泡沫细胞的表型和功能变化， 单核细胞与动脉粥样硬化的发病机制有关。目标2将检验髓样细胞- 巨胞饮调节因子NHE 1的特异性缺失抑制体内泡沫单核细胞的形成。单核细胞 将从注射AAV 8-PCSK 9的NHE 1f/f Lysm Cre+和同窝Cre-小鼠中分离并分析脂质 含量、炎性细胞因子分泌、炎性标志物和粘附能力。此外，我们将使用 野生型和CD 36-/-/SRA-/-小鼠，以评估FDA批准的抑制 在减弱循环泡沫状单核细胞水平中的巨胞饮作用。这个项目将使我能够开发新的 技术技能，获得专业知识，进行严格的，假设驱动的研究，并提高我的独立 skills.该项目将在Gabor Csanyi博士和Neal Weintraub博士的指导下进行， 奥古斯塔大学格鲁吉亚医学院血管生物学中心， 成功的博士前和博士后培训。拟议的项目是3年的资金与目标分为 在三年的资助中，最终在第三年年底进行了论文答辩。我们预计 这项新提议的发现将确定巨胞饮作用是单核细胞 内化脂质，并将强调这一途径作为动脉粥样硬化的新的治疗靶点。