iPLA2 as a Target in Vascular Inflammation, Neointima Formation, and Restenosis

iPLA2 作为血管炎症、新内膜形成和再狭窄的靶标

• 批准号: 9275392
• 负责人: Zhenheng Guo
• 金额: --
• 依托单位: VA MEDICAL CENTER - LEXINGTON, KY
• 依托单位国家: 美国
• 财政年份: 2014
• 资助国家: 美国
• 起止时间: 2014-10-01 至 2018-09-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/9275392
• 关键词: Adopted; Animal Genetics; Animal Model; Antisense Oligonucleotides; Arachidonate 15-Lipoxygenase; Biochemical; Blood; Blood Vessels; Calcium; Carotid Arteries; Cause of Death; Cessation of life; Chest Pain; Congestive Heart Failure; Coronary; Coronary Artery Bypass; Coronary artery; Coronary heart disease; Development; Endothelial Cells; Enzymes; Event; Gel; Genetic; Goals; Healthcare Systems; Heart; Hospitalization; Hypoxia; Incidence; Injury; Knockout Mice; Lead; Leukocytes; Ligation; Lipids; Lysophospholipids; Mediating; Metals; Modality; Modeling; Molecular; Molecular Genetics; Mus; Muscle Cells; Myocardial Infarction; Myocardial Ischemia; Nonesterified Fatty Acids; Oxygen; Patients; Pharmaceutical Preparations; Pharmacology; Phospholipase; Phospholipase A2; Phospholipids; Physiological; Play; Pluronics; Prevention; Risk; Role; Scheme; Smooth Muscle; Stents; Tamoxifen; Testing; Therapeutic Effect; United States; Vascular Smooth Muscle; Woman; cost; femoral artery; genetic approach; human disease; injured; macrophage; member; men; monocyte; mouse model; neointima formation; new therapeutic target; novel; overexpression; percutaneous coronary intervention; prevent; public health relevance; restenosis; stent thrombosis; therapeutic target; vascular inflammation; vascular smooth muscle cell proliferation

DESCRIPTION (provided by applicant): Coronary heart disease is the single leading cause of death among men and women in the United States. Coronary revascularization, including coronary artery bypass graft (CABG) and percutaneous coronary intervention (PCI) is the most common modality in patients with coronary diseases. However, it is also among the most costly, and is often associated with a high incidence of restenosis. Although the rate of restenosis is significantly reduced with the use of bare-metal stent (BMS) and particularly with drug-eluting stent (DES), a persistently high rate of restenosis after BMS and an increased risk of in-stent thrombosis with DES have been encountered as significant limitations to the long-term efficacy of coronary revascularization. With a long-term goal of identifying novel therapeutic targets for coronary heart disease, the current application specifically investigates a potentially critical role of calcium independent phospholipase A2b (iPLA2b) in vascular inflammation, re-endothelialization, and neointima formation in a mouse femoral artery wire injury model. iPLA2b is a member of the phospholipase A2 superfamily that acts on phospholipids to produce a free fatty acid and a lysophospholipid. iPLA2b is expressed in vascular smooth muscle cells (VSMC) and is implicated in many human diseases. Whereas little is known about the role of other PLA2 in vascular injury-induced neointima formation, substantial evidence, including pharmacological inhibition, antisense oligonucleotide down- rgulation, genetic deletion, and smooth muscle-specific overexpression, consistently demonstrated that iPLA2b plays a critical role in vascular inflammation and neointima formation in a mouse carotid artery ligation model. To investigate whether targeting smooth muscle-specific iPLA2b is sufficient to reduce vascular inflammation and neointima formation, a femoral artery injury model that better mimics PCI was established, a novel tamoxifen-inducible smooth muscle-specific iPLA2b knockout mouse model (SM-iPLA2b-iKO) was developed, and the current proposal hypothesizes that activation of iPLA2b in VSMC by vascular injury plays a key role in wire injury-induced vascular inflammation, re-endothelialization, and neointima formation, thereby significantly contributing to the development of restenosis after coronary revascularization. Three Specific Aims are: 1) To test the hypothesis that smooth muscle-specific iPLA2b plays a critical role in the initiation of vascular inflammation, re-endothelialization, and neointima formation; 2) To determine the molecular mechanism that underlies wire injury-induced iPLA2b activation, vascular inflammation, and neointima formation; 3) To investigate whether post-wire injury molecular and genetic targeting iPLA2b has an effect on the progression of re-endothelialization, vascular inflammation, and neointima formation. To achieve this goal, a well established and most physiological relevant femoral artery wire injury model will be used in combination with several novel and established genetic animal models (SM- iPLA2b-iKO, SM-HIF-1a-iKO, and SM-iPLA2b-Tg/12/15-LO) to selectively inhibit or activate iPLA2b, HIF-1a, and 12/15-LO before and after wire injury. Injured and non-injured femoral arteries will be isolated and then subjected to molecular, immunohistological, and biochemical studies to determine the role of iPLA2b in vascular inflammation and neointima formation. Results from the proposed studies may modify the current paradigm that the initiation and early progression of vascular inflammation are largely attributed to coordinated interactions among monocytes/macrophages, leukocytes, and endothelial cells by providing the first direct experimental evidence that VSMC also play a critical role in these early key events. Importantly, results from the proposed studies will elucidate specific mechanisms that could lead to the identification of iPLA2b as a novel potential therapeutic target for the prevention and treatment of vascular inflammation, re- endothelialization, neointima formation, and restenosis.

描述(由申请人提供)： 在美国，冠心病是导致男性和女性死亡的唯一主要原因。冠状动脉血运重建术，包括冠状动脉旁路移植术(CABG)和经皮冠状动脉介入治疗(PCI)是冠心病患者最常见的方法。然而，它也是最昂贵的之一，而且经常与再狭窄的高发生率有关。尽管再狭窄率随着使用 裸金属支架(BMS)，尤其是药物洗脱支架(DES)，BMS后持续较高的再狭窄率和支架内血栓形成的风险增加是冠状动脉血运重建术长期疗效的显著限制。为了确定冠心病的新治疗靶点，目前的应用专门研究了钙非依赖性磷脂酶A2B(IPLA2b)在小鼠股动脉钢丝损伤模型中的血管炎症、再内皮化和新内膜形成中的潜在关键作用。IPLA2b是磷脂酶A2超家族的成员，作用于磷脂产生游离脂肪酸和溶血磷脂。IPLA2b在血管平滑肌细胞(VSMC)中表达，与多种人类疾病有关。尽管其他PLA2在血管损伤诱导的新生内膜形成中的作用知之甚少，但大量证据，包括药物抑制、反义寡核苷酸下调、基因缺失和平滑肌特异性过度表达，一直表明iPLA2b在小鼠颈动脉结扎模型的血管炎症和新生内膜形成中发挥关键作用。为探讨靶向血管内皮细胞特异性iPLA2b是否足以减少血管炎症和新生内膜的形成，建立了一种更好地模拟经皮冠状动脉介入治疗的股动脉损伤模型，建立了一种新的三苯氧胺诱导的血管特异性iPLA2b基因敲除小鼠模型(SM-iPLA2b-IKO)，本研究假设血管损伤激活VSMC中的iPLA2b在金属丝损伤诱导的血管炎症、再内皮化和新生内膜形成中起关键作用，从而显著促进冠状动脉血运重建后再狭窄的发展。三个具体目标是：1)验证假设，即平滑肌特异性的iPLA2b在启动血管炎症、再内皮化和新内膜形成中起关键作用；2)确定钢丝损伤诱导的iPLA2b激活、血管炎症和新内膜形成的分子机制；3)研究钢丝损伤后分子和基因靶向iPLA2b是否影响再内皮化、血管炎症和新内膜形成的进展。为了达到这一目的，我们将使用一个成熟的、最具生理学相关性的股动脉钢丝损伤模型，结合几个新的和已建立的遗传动物模型(SM-iPLA2b-Iko、SM-HIF-1a-Iko和SM-iPLA2b-TG/12/15-LO)来选择性地抑制或激活钢丝损伤前后的iPLA2b、HIF-1a和12/15-Lo。受损和未受损的股动脉将被分离，然后接受分子、免疫组织学和生化研究，以确定iPLA2b在血管炎症和新生内膜形成中的作用。这项研究的结果可能会修正目前的研究范式，即血管炎症的启动和早期进展在很大程度上归因于单核/巨噬细胞、白细胞和内皮细胞之间的协调相互作用，因为它提供了第一个直接的实验证据，表明VSMC在这些早期关键事件中也发挥了关键作用。重要的是，拟议研究的结果将阐明iPLA2b作为预防和治疗血管炎症、再内皮化、新的内膜形成和再狭窄的新的潜在治疗靶点的具体机制。