LIPOXYGENASE PRODUCTS IN GLOMERULAR IMMUNE INJURY

在以前的研究中，我们表征了花生四烯酸5-，和 15-脂氧合酶(LO)产物[白三烯(LTS和脂氧素(LXs)]) 大鼠肾单位。随后，我们和其他人提供了证据支持 LTS在促进白细胞浸润/活化、蛋白尿、 实验性肾小球系膜细胞增殖与功能恶化 大鼠肾小球肾炎模型。LTS和LXX在肾小球中的形成 炎症是由中性粒细胞/巨噬细胞内的总合成引起的，或者 通过白细胞产生的中间产物的跨细胞代谢， LTA4，通过内皮细胞、系膜细胞和浸润性血小板 产量LTC4、D4、B4和LXA4LT生物合成受到严格调控； 主要增加发生在受伤的前48小时，随后 抑制到损伤前的水平，表明内源性 抗炎途径。我们发现了15-LO的证据 产品LXA4和15-(S)-羟基二十碳四烯酸[15-(S)-HETE}，施加 中性粒细胞和巨噬细胞的强大抗炎作用- 肾小球免疫损伤的介导期。其中包括直接 抑制LT的合成和作用。值得注意的是， 15-LO产物从LT拮抗延伸到普遍的下调 中性粒细胞的趋化、黏附和激活，以及标记 抑制巨噬细胞活化。在这里，我们建议研究 生物合成和病理生理调控的机制 这些内源性白细胞活化途径的意义 肾小球炎症过程中的失活。具体地说，我们将使用 人血单核细胞(PEM)和系膜细胞(MC)来验证这一假设 巨噬细胞和淋巴细胞释放的特定细胞因子在 在实现从支持向反对的净平衡转变中发挥关键作用 随着肾小球炎症的进展，炎性脂质介质的释放 从急性到亚急性期。我们的发现证明了直接监管 5-LO、15-LO、LTA4-水解酶、5-LO、15-LO、LTA4-水解酶、5-LO、15-LO、LTA4-水解酶的基因表达水平 脂氧合酶激活蛋白(FIFP)、白介素1b(IL-1b)、白介素4、白介素2 13，以及PBM和MC中的g-干扰素，从而为 调节白细胞内二十烷类化合物的合成以及通过 跨细胞路线。我们将把这些研究与体内模型相结合 大鼠和小鼠肾小球肾炎的病理生理相关性 这些相互作用中的一部分进行了测试。我们将评估肾小球功能和 5-LO和15-LO基因缺失大鼠肾小球损伤的组织学变化 在小鼠和肾小球肾炎大鼠中，肾脏二十烷基磺酸酶或 体内转基因调控细胞因子基因的表达 技巧。洞察促肾上腺皮质激素内源性平衡的调节 而肾小球肾炎期间的炎症影响可能提供 制定旨在逮捕的干预战略的机会 免疫复合物引发的疾病通过优先表达抗- 炎症介质。

In previous studies, we characterized the actions of arachidonate 5-, and 15- lipoxygenase (LO) products {leukotrienes (LTs and lipoxins (LXs)] in the rat nephron. Subsequently, we and others provided evidence supporting a role for LTs in promoting leukocyte infiltration/activation, proteinuria, mesangial proliferation and functional deterioration during experimental glomerulonephritis in the rat. Formation of LTs and LXx in glomerular inflammation arises from total synthesis within neutrophils/macrophages, or through transcellular metabolism of the leukocyte-generated intermediate, LTA4, by endothelial and mesangial cells and infiltrating platelets, to yield LTs C4, D4, B4, and lXA4.LT biosynthesis is regulated tightly; a major increase occuring in the first 48 hrs of injury, followed by suppression to pre-injury levels, suggesting the activation of endogenous counter-inflammatory pathways. We have discovered evidence that the 15-LO products, LXA4 and 15-(S)-hydroxyeicosatetraenoic acid [15-(S)-HETE}, exert potent anti-inflammatory actions during the neutrophil and macrophage- mediated phases of glomerular immune injury. These include direct inhibition of LT synthesis and actions. Significantly, the activities of 15-LO products extend beyond LT antagonism to a generalized down-regulation of neutrophil chemotaxis, adhesion, and activation, as well as marked suppression of macrophage activation. Here, we propose to examine the mechanisms underlying the regulation of biosynthesis and pathophysiologic significance of these endogenous pathways of leukocyte activation and inactivation during glomerular inflammation. Specifically, we will use human blood monocytes (PEM) and mesangial cells (MC) to test the hypothesis that specific cytokines released from macrophages and lymphocytes play a crucial role in effecting the switch in the net balance from pro- to anti- inflammatory lipid mediator release, as glomerular inflammation progress from acute to subacute phases. Our findings demonstrate direct regulation of the levels of mRNA encoding for 5-LO, 15-LO, LTA4-hydrolase and five- lipoxygenase activating protein (FLAP), by interleukin 1b(IL-1b), IL-4, IL- 13, and g-interferon in PBM and MC, thereby providing a mechanism for the regulation of eicosanoid synthesis in leukocytes, as well as via transcellular routes. We will couple these studies with in vivo models of glomerulonephritis in rats and mice in which the pathophysiologic relevance of these interactions is tested. We will assess glomerular functions and histologic changes during glomerular injury in 5- and 15-LO gene-deleted mice, and in glomerulonephritis rats in which renal eicosanoid enzyme or cytokine gene expression are manipulated by in vivo transfection techniques. Insight into the regulation of the endogenous balance of pro- and inflammatory influences during glomerulonephritis may provide an opportunity for the design of interventional strategies aimed at arresting immune complex-initiated diseases through preferential expression of anti- inflammatory mediators.