Montero Angel, Uda Susumu, Kelavkar Uddhav, Yoshimura Ashio, Badr Kamal F, Munger Karen A
Renal Division, Emory University School of Medicine, Atlanta, USA.
J Nephrol. 2003 Sep-Oct;16(5):682-90.
The binding of 5-lipoxygenase (5-LO) to 5-LO activating protein (FLAP) is a prerequisite for subsequent formation of leukotrienes from arachidonic acid.
We investigated the localization of FLAP in a rat model of accelerated anti-glomerular basement membrane nephritis and protein expression in cultured rat glomerular endothelial cells.
As expected, 5-LO staining was intense and localized exclusively to perinuclear region and inside the nucleus of leukocytes and macrophages. In these cells, FLAP immunoreactivity co-localized with that of 5-LO, and was restricted to nuclear envelope. Surprisingly, intense nuclear and cytoplasmic staining for FLAP was also observed in glomerular endothelial cells in early experimental glomerulonephritis. Although 5-LO and FLAP mRNA were detected in cultured rat glomerular endothelial cells by RT-PCR, Western blot revealed only FLAP and no 5-LO protein. FLAP protein was regulated in glomerular endothelial cells by the proinflammatory cytokine, interferon-gamma, in a dose-dependent manner.
The unexpected discovery of FLAP in glomerular endothelial cells in this model of glomerulonephritis, coupled with our demonstration that oral FLAP antagonist therapy reduces proteinuria in human glomerulonephritis and animal models of diabetes, provides further impetus to examine the role of this pro-inflammatory protein in glomerular immune injury.
5-脂氧合酶（5-LO）与5-脂氧合酶激活蛋白（FLAP）的结合是随后从花生四烯酸形成白三烯的前提条件。
我们研究了FLAP在加速性抗肾小球基底膜肾炎大鼠模型中的定位以及在培养的大鼠肾小球内皮细胞中的蛋白表达。
正如预期的那样，5-LO染色强烈，且仅定位于白细胞和巨噬细胞的核周区域及细胞核内。在这些细胞中，FLAP免疫反应性与5-LO的免疫反应性共定位，且局限于核膜。令人惊讶的是，在早期实验性肾小球肾炎的肾小球内皮细胞中也观察到了强烈的FLAP核染色和胞质染色。虽然通过逆转录聚合酶链反应（RT-PCR）在培养的大鼠肾小球内皮细胞中检测到了5-LO和FLAP信使核糖核酸（mRNA），但蛋白质印迹法仅显示有FLAP，而没有5-LO蛋白。促炎细胞因子γ干扰素以剂量依赖的方式调节肾小球内皮细胞中的FLAP蛋白。
在该肾小球肾炎模型的肾小球内皮细胞中意外发现FLAP，再加上我们证明口服FLAP拮抗剂疗法可降低人类肾小球肾炎和糖尿病动物模型中的蛋白尿，这为研究这种促炎蛋白在肾小球免疫损伤中的作用提供了进一步的动力。
