Macrophage- associated lipin-1 lipid synthesis regulates foam cell inflammatory responses

巨噬细胞相关的lipin-1脂质合成调节泡沫细胞炎症反应

• 批准号: 9236423
• 负责人: Matthew Dale Woolard
• 金额: $ 36.25万
• 依托单位: LOUISIANA STATE UNIV HSC SHREVEPORT
• 依托单位国家: 美国
• 财政年份: 2017
• 资助国家: 美国
• 起止时间: 2017-01-01 至 2020-12-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/9236423
• 关键词: Americas; Arterial Fatty Streak; Arterial Intimas; Atherosclerosis; Biogenesis; Biology; Bone Marrow; Cardiovascular Diseases; Characteristics; Cholesterol; Data; Dependovirus; Development; Diglycerides; Foam Cells; Future; Generations; Goals; Immunosuppression; Inflammation; Inflammatory; Inflammatory Response; Knock-out; Knowledge; Laboratories; Lipids; Low Density Lipoprotein Receptor; Low-Density Lipoproteins; MAPK3 gene; Mediating; Modeling; Molecular; Monitor; Mus; Myelogenous; Myeloid Cells; Nature; Outcome; PRKCA gene; Pharmacology; Phenotype; Physiological; Process; Production; Proprotein Convertases; Quantitative Reverse Transcriptase PCR; Research; Risk; Role; Serotyping; Signal Transduction; Small Interfering RNA; Subtilisins; Testing; Therapeutic; Time; Wild Type Mouse; Work; burden of illness; cytokine; defined contribution; expectation; experimental study; genetic manipulation; hypercholesterolemia; in vivo; innovation; innovative technologies; lipine; macrophage; novel; phosphatidate; response; therapeutic target

The proposed research application seeks a better understanding of the underpinnings of foam cell inflammatory responses that promote atheroma formation, plaque progression, and ultimately plaque instability leading to catastrophic cardiovascular disease (CVD). Hypercholesterolemia results in the formation of modified low den- sity lipoproteins (modLDL) in the arterial intima causing atherosclerosis. ModLDLs elicit a pro-inflammatory re- sponse from macrophages that drives atherosclerosis, leading to catastrophic CVD. The goal of my laboratory is to elucidate the mechanisms that mediate modLDL-elicited inflammatory responses, as this understanding may allow us to better treat CVD than current therapies which only reduce CVD by 30%. The lipid-laden pheno- type that is characteristic of macrophage foam cells is due to lipid droplet biogenesis. Lipid droplet biogenesis requires glycerolipid synthesis, however glycerolipid synthesis in and of itself is not thought to contribute to foam cell inflammatory responses. During glycerolipid synthesis, lipin-1 converts phosphatidate to diglyceride as the penultimate step of lipid droplet generation. My laboratory has demonstrated for the first time that lipin-1 directly contributes to the modLDL-elicited pro-inflammatory state of macrophages, suggesting that glycerolipid synthe- sis may contribute to atherosclerosis inflammation. The objective of this proposal is to define the mechanism by which lipin-1 regulates the modLDL-elicited pro-inflammatory responses that contribute to atherosclerosis. Our central hypothesis is that modLDL induces lipin-1 enzymatic activity as part of glycerolipid synthesis, causing sustained activation of a signaling axis responsible for modLDL-elicited pro-inflammatory responses that promote atherosclerosis. We will test our central hypothesis and accomplish the objective of this application by pursuing three specific aims: 1) Understanding how lipin-1 enzymatic activity regulates modLDL-elicited diglyceride pro- duction and diglyceride mediated responses in macrophages. 2) Determine if lipin-1 mediates modLDL-loaded macrophage hyper-responsiveness. 3) Define the extent to which lipin-1 in myeloid cells promotes atheroscle- rosis. In aims 1 and 2, we propose to genetically restore lipin-1 enzymatic activity in bone marrow-derived mac- rophages from our newly developed mouse that lacks lipin-1 enzymatic activity from myeloid cells only. We will examine the physiological outcome of diglyceride-dependent signaling, cJun activity, and pro-inflammatory re- sponses. During aim 3 we will use our novel mouse in which lipin-1 enzymatic activity is lacking in myeloid cells and we will monitor atherosclerotic progression and plaque inflammation using the LDL receptor knockout (LDLR- /-) and AAV8-PCSK9D377Y models of atherosclerosis. These proposed experiments will provide support to the innovative idea that lipin-1 enzymatic activity, as part of glycerolipid synthesis in macrophages, is a key contrib- utor to inflammation that drives atherosclerotic progression. This work is significant as it may result in the future development of pharmacological strategies that modulate glycerolipid synthesis in foam cells to reduce athero- sclerotic inflammation without causing systemic immunosuppression, thus reducing CVD burden.

拟议的研究应用寻求更好地了解泡沫细胞炎症的基础。 促进动脉粥样硬化形成、斑块进展并最终导致斑块不稳定的反应 灾难性心血管疾病(CVD)。高胆固醇血症可导致低密度脂蛋白的形成。 动脉内膜中密度脂蛋白(ModLDL)导致动脉粥样硬化。模块低密度脂蛋白诱导促炎再- 巨噬细胞的海绵会导致动脉粥样硬化，导致灾难性的心血管疾病。我的实验室的目标是 就是阐明介导modLDL引起的炎症反应的机制，因为这种理解 可能会让我们比目前的治疗方法更好地治疗心血管疾病，目前的治疗方法只能将心血管疾病减少30%。富含脂质的苯酚- 巨噬细胞泡沫细胞特有的类型是由于脂滴的生物发生。脂滴的生物发生 需要甘油脂合成，但甘油脂合成本身并不被认为对泡沫有贡献 细胞炎症反应。在甘油脂合成过程中，Lipin-1将磷脂酸盐转化为甘油二酯。 脂滴生成的倒数第二步。我的实验室首次直接证明了脂蛋白-1 有助于modLDL诱导的巨噬细胞的促炎状态，提示甘油脂合成酶- SIS可能参与动脉粥样硬化性炎症。这项提案的目标是通过以下方式定义该机制 哪种脂类-1调节modLDL引发的促炎反应，这些反应有助于动脉粥样硬化。我们的 中心假设是modLDL诱导Lipin-1酶活性作为甘油脂合成的一部分，导致 持续激活一个信号轴，负责modLDL引发的促炎反应，促进 动脉硬化。我们将测试我们的中心假设，并通过以下方式实现此应用程序的目标 三个具体目标：1)了解脂蛋白-1酶活性如何调节由低密度脂蛋白诱导的二甘油三酯前体- 诱导和双甘油三酯介导巨噬细胞的反应。2)确定Lipin-1是否介导modLDL负载 巨噬细胞高反应性。3)确定髓系细胞中的脂类-1促进动脉粥样硬化的程度- 精神错乱。在目标1和目标2中，我们建议从基因上恢复骨髓来源的Mac-Lipin-1的酶活性。 来自我们新开发的小鼠的噬菌体，它缺乏仅来自髓系细胞的脂类-1酶活性。我们会 检查依赖于甘油三酯的信号、cJun活性和促炎症反应的生理结果 海绵。在Aim 3中，我们将使用我们的新型小鼠，在该小鼠中，髓系细胞中缺乏Lipin-1酶活性 我们将使用低密度脂蛋白受体基因敲除(LDLR-)来监测动脉粥样硬化进展和斑块炎症。 /-)和AAV8-PCSK9D377Y动脉粥样硬化模型。这些拟议的实验将为 创新的想法是，作为巨噬细胞甘油脂合成的一部分，Lipin-1酶活性是一个关键的控制因素。 导致动脉粥样硬化进展的炎症反应。这项工作意义重大，因为它可能会在未来 调控泡沫细胞甘油脂合成以减少动脉粥样硬化的药理策略研究进展 硬化性炎症不会引起全身免疫抑制，从而减轻心血管疾病负担。