REGULATION OF MONOCYTE 15-LIPOXYGENASE EXPRESSION

单核细胞是炎症反应的主要参与者，是慢性阻塞性肺疾病的中枢介质。 发炎。单核细胞被认为在动脉粥样硬化病变病理中起重要作用。在……里面 动脉粥样硬化病变，单核/巨噬细胞已被证明表达脂质氧化 酶，15-脂氧合酶(15LO)，通过氧化产生有效的炎症介质 磷脂、胆固醇酯和游离脂肪酸。这种酶的产物中独一无二的是 氧化亚油酸酯(13-S-HPODE)，我们已经证明它是主要的氧化脂肪酸 动脉粥样硬化性病变，多数以酯化形式出现。正常单核细胞不表达15LO， 但是通过暴露在细胞因子IL-13和这种酶的表达已经被诱导这样做 在动脉粥样硬化动物模型中与疾病进展相关。第一项建议的研究 这项应用的目的是识别新的IL-13触发的信号转导通路，负责 诱导原代人单核细胞表达15LO基因及其与双核表达的关系 调节15LO的关键转录因子STATS的磷酸化。我们还将调查 STATS在15LO特异性转录激活中的直接和间接作用。建议进行的研究 Aim 2将探索这样的假设，即15LO的诱导是许多 观察到的调节清道夫受体CD36表达的途径。这些产品的新颖性 研究源于通过使用15LO和CD36通路的相互作用 创新的方法来具体剖析这些通路在完好的原始人身上的作用 单核细胞。其中包括我们小组的发现，单核细胞特别有利于 反义寡核苷酸对特定蛋白表达的操纵也是由于最近的 突破性进展，使原代人类单核细胞得以高效转化。我们还将定义 我们最近发现氧化磷脂处理单核细胞的机制 导致15LO表达的显著抑制。选择性氧化磷脂可能因此而干扰 与脂氧合酶在动脉粥样硬化病变中的表达有关。这些研究将大大增强 我们对15LO表达的信号机制及其影响的理解 CD36的表达以及CD36抑制15LO表达的机制。 这些途径的调节将影响氧化磷脂、氧化胆固醇酯的形成 和氧化脂肪酸以及调节病变巨噬细胞泡沫细胞的形成和进展 动脉粥样硬化病变。调控15LO和CD36表达的新途径的鉴定 可能会提出新的治疗方法，可以用来干扰这一途径及其在 慢性炎症性疾病，如动脉粥样硬化。

Monocytes are major participants in inflammatory responses and are central mediators of chronic inflammation. Monocytes are believed to significantly contribute to atherosclerotic lesion pathology. In atherosclerotic lesions, monocyte/macrophages have been shown to expressthe lipid-oxidizing enzyme, 15-lipoxygenase (15LO) that produces potent inflammatory mediators by oxidizing phospholipids, cholesterol esters and free fatty acids. Unique among the products of this enzyme are oxidized linoleate (13-S-HPODE), which we have shown to be the major oxidized fatty acid in atherosclerotic lesions with most present in esterified form. Normal monocytes do not express 15LO, but are induced to do so by exposure to the cytokine IL-13 and expression of this enzyme has been correlated with disease progression in animal models of atherosclerosis. Studies proposed in the first aim of this application will identify novel IL-13-triggered signal transduction pathways responsible for inducing 15LO gene expression in primary human monocytes and relate them to the dual phosphorylation of StatS, a critical transcription factor regulating 15LO. We will also investigate the direct versus indirect role of StatS in specific transcriptional activation of 15LO. The studies proposed in Aim 2 will explore the hypothesis that the induction of 15LO is a critical regulatory step for many of the pathways observed to regulate the expression of the scavenger receptor CD36. The novelty of these studies is derived from elucidating the interaction of the 15LO and CD36 pathways through the use of innovative approaches to specifically dissect the roles of these pathways in intact, primary human monocytes. These include the discovery by our group that monocytes are particularly conducive to antisense oligodeoxyribonucleotide manipulation of specific protein expression and also due to a recent breakthrough allowing efficient transfection of primary human monocytes. We will also define the mechanisms involved in our recent finding that treatment of monocytes with oxidized phospholipids causes dramatic inhibition of 15LO expression. Select oxidized phospholipids may thereforeinterfere with the lipoxygenase expression in atherosclerotic lesions. These studies will substantially enhance our understanding of the signaling mechanisms involved in the expression of 15LO and their impact on the expression of CD36 as well as defining the mechanism of CD36 inhibition of 15LO expression. Modulation of these pathways will impact formation of oxidized phospholipids, oxidized cholesterol ester and oxidized fatty acids as well as modulate lesion macrophage foam cell formation and progression of atherosclerotic lesions. The identification of new pathways that regulate 15LO and CD36 expression will likely suggest novel therapies that may be employed to interfere with this pathway and its role in chronic inflammatory disease such as atherosclerosis.