Regulation of PAF Acetylhydrolase Expression by Oxidized Phospholipids

氧化磷脂对 PAF 乙酰水解酶表达的调节

• 批准号: 7659497
• 负责人: SUZANNE E BARBOUR
• 金额: $ 18.08万
• 依托单位: VIRGINIA COMMONWEALTH UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2008
• 资助国家: 美国
• 起止时间: 2008-08-01 至 2012-07-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7659497
• 关键词: 5' Flanking Region; Arterial Fatty Streak; Atherosclerosis; Binding; Biological Assay; Boxing; CD14 Antigen; CD14 gene; Calcium; Cardiovascular Diseases; Cellular biology; Complex; Dendritic Cells; Disease; Enzymes; Event; Genes; Genetic Transcription; Incidence; Interleukin-6; Modeling; Molecular; Pathogenesis; Phospholipids; Phosphorylation; Phosphorylcholine; Physiological; Platelet Activating Factor; Principal Investigator; Prostaglandin Receptor; Prostaglandins; Regulation; Research Personnel; Role; STAT3 gene; Severities; TLR4 gene; Testing; Universities; Vascular Diseases; Virginia; cytokine; dinitroaminophenol; insight; lipid mediator; lipoprotein-associated phospholipase A(2); novel; oxidized low density lipoprotein; particle; prevent; prostaglandin EP2 receptor; transcription factor

DESCRIPTION (provided by applicant): Platelet-activating factor acetylhydrolase (PAFAH) also known as the lipoprotein-associated phospholipase A2 is a calcium-independent acylhydrolase that catabolizes oxidized phospholipids (oxPL) in the oxidized LDL (oxLDL) particle as well as the lipid mediator platelet-activating factor (PAF). Many recent studies have correlated PAFAH activity with severity of vascular disease and atherosclerosis. Despite the unquestioned importance of this enzyme in the pathogenesis of atherosclerosis and other vascular disease, very little is known about mechanisms regulating its expression and activity. Our preliminary studies indicate that PAFAH expression is induced by oxidized phospholipids (oxPL), derivatives of 1-palmitoyl-2-arachidonoyl-sn-glycero-3-phosphocholine, a component of oxLDL. This provides us with a unique model that we will use to delineate the molecular mechanisms controlling PAFAH expression in the atherosclerotic lesion. We hypothesize that long chain, prostaglandin-like oxPL induce PAFAH by binding to the CD14/ TLR4 complex and the EP2 prostaglandin receptor on dendritic cells in the developing atherosclerotic lesion. These interactions are proposed to induce interleukin 6 (IL6) and the phosphorylation and activation of key transcription factors, events essential for optimal transcription of the PAFAH gene. To test this hypothesis, we propose the following specific aims: 1) Investigate Roles of EP2, IL6, and CD14/ TLR4 in oxPL Induction of PAFAH and 2) Investigate Molecular Mechanisms of oxPL Induction of PAFAH. In Aim 1, we will test the hypothesis that oxPL binding to EP2 and/ or the TLR4-CD14 receptor complex induces IL6 and that this cytokine is essential for optimal PAFAH induction. In Aim 2, we will investigate role of a GC-box, Sp1, and Sp3 in induction of PAFAH by oxPL and determine whether PAFAH induction is dependent on phosphorylation of Sp1/ Sp3 and/ or the association of Sp1 with activated STAT3. We have assembled a unique team of investigators for this purpose, including Dr. Norbert Leitinger (University of Virginia), a pioneer in the study of oxPL, Dr. Zendra Zehner (VCU), and expert in the transcriptional assays, DNAP, and ChIP analyses required for determination of the molecular mechanism of PAFAH induction by oxPL, and the Principal Investigator, Dr. Suzanne Barbour, an expert in the PAFAH enzyme and dendritic cell (DC) biology. Together, the proposed studies should provide insights into the physiological mechanisms that control PAFAH expression in vascular disease. We anticipate that our studies may uncover novel mechanisms to control PAFAH that could eventually result in treatments to prevent initiation or slow progression of atherosclerosis and other vascular diseases. Project Narrative: Platelet-activating Factor Acetylhydrolase (PAFAH) is the lipoprotein-associated phospholipase A2 that has been correlated with the incidence and severity of cardiovascular disease. Preliminary studies from this group of investigators indicate that PAFAH is induced by oxidized phospholipids (oxPL) in the oxidized low density lipoprotein (LDL) particle. The objective of this study is to delineate the molecular mechanisms of PAFAH induction by oxPL in hopes that this will uncover novel mechanisms for regulating the enzyme and thereby controlling cardiovascular disease.

描述（由申请人提供）：血小板激活因子乙酰水解酶（PAFAH）也称为脂蛋白相关的磷脂酶A2是一种与氧化的磷脂（Oxpl）分解氧化的LDL（oxllllllll）粒子以及Paft ripAct的氧化磷脂（OXPL）的氧化磷脂（OXPL），以及PAFTIST粒子及PAFT ACTIST PALTACT（PAFT）。许多最近的研究将Pafah活性与血管疾病和动脉粥样硬化的严重程度相关。尽管该酶在动脉粥样硬化和其他血管疾病的发病机理中毫无疑问，但对调节其表达和活性的机制知之甚少。我们的初步研究表明，PafaH表达是由1-甲米酰基-2-芳基-2-芳基烯酰基-SN-甘油-3-磷脂的氧化磷脂（OXPL）诱导的，OXLDL。这为我们提供了一个独特的模型，我们将使用该模型来描述控制动脉粥样硬化病变中Pafah表达的分子机制。我们假设该长链，前列腺素样的OXPL通过与CD14/ TLR4复合物结合和EP2前列腺素受体的结合在发育中的动脉粥样硬化病变中诱导Pafah。提出这些相互作用是为了诱导白介素6（IL6）以及关键转录因子的磷酸化和激活，这对于PAFAH基因的最佳转录至关重要。为了检验这一假设，我们提出了以下特定目的：1）研究EP2，IL6和CD14/ TLR4在Pafah的OXPL诱导中的作用和2）研究Pafah的OXPL诱导的分子机制。在AIM 1中，我们将检验以下假设：OXPL结合EP2和/或TLR4-CD14受体复合物诱导IL6，并且该细胞因子对于最佳PAFAF诱导至关重要。在AIM 2中，我们将研究GC-Box，SP1和SP3在OXPL诱导Pafah中的作用，并确定Pafah诱导是否取决于SP1/ SP3和/或SP1与激活STAT3的磷酸化。 We have assembled a unique team of investigators for this purpose, including Dr. Norbert Leitinger (University of Virginia), a pioneer in the study of oxPL, Dr. Zendra Zehner (VCU), and expert in the transcriptional assays, DNAP, and ChIP analyses required for determination of the molecular mechanism of PAFAH induction by oxPL, and the Principal Investigator, Dr. Suzanne Barbour, an expert in the PAFAH酶和树突状细胞（DC）生物学。拟议的研究一起，应提供有关控制Pafah表达血管疾病的生理机制的见解。我们预计我们的研究可能会发现控制PAFAH的新型机制，最终可能导致治疗以防止动脉粥样硬化和其他血管疾病的启动或缓慢进展。项目叙述：血小板激活因子乙酰水合酶（PAFAH）是与脂蛋白相关的磷脂酶A2，与心血管疾病的发生率和严重程度相关。这组研究人员的初步研究表明，氧化的低密度脂蛋白（LDL）颗粒中的氧化磷脂（OXPL）诱导了Pafah。这项研究的目的是通过OXPL描述Pafah诱导的分子机制，希望这将发现调节酶的新机制，从而控制心血管疾病。