NOVEL LIPID PRECURSOR OF MACROPHAGE ARACHIDONATE

巨噬细胞花生四烯酸的新型脂质前体

• 批准号: 6110245
• 负责人: B M WAITE
• 金额: $ 22万
• 依托单位: WAKE FOREST UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 1998
• 资助国家: 美国
• 起止时间: 1998-08-01 至 2001-07-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6110245
• 关键词: alveolar macrophages; arachidonate; eicosanoid metabolism; fatty acid biosynthesis; fatty acid metabolism; gel filtration chromatography; glycerophosphates; isomer; lipid metabolism; lung injury; lysosomes; stereochemistry; synthetic enzyme; thin layer chromatography

Alveolar macrophages play a key role in lung homeostasis and macrophage lipid metabolism, concomitant with synthesis of its lipid mediators, significantly influences normal and pathophysiologic lung function. Therefore, our investigations of macrophage lipid metabolism are vital to understanding lung homeostasis and the variety of lung dysfunctions. Bis(monoacylglycerol)phosphate (BMP) comprises 18% of the phospholipids in alveolar macrophages. This phospholipid is unique in eukaryotic tissue with its sn-glycero-1-phosphoryl-sn-1'-glycerol stereoconfiguration that contrasts with the usual sn-glycero-3-phosphoryl-sn- 1'-glycerol isomer found in all other phospholipids. Evidence exists, however, that the sn-glycero-3-phosphoryl- sn-1'glycerol is synthesized also but does not accumulate in macrophages. BMP is derived from exogenous phosphatidylglycerol from lung surfactant and contains high levels of unsaturated fatty acids including arachidonic acid that can be involved in eicosanoid synthesis. For these reasons we propose to study: 1) The mechanism(s) by which both BMP isomers is synthesized 2) How the fatty acids are turned ever in BMP 3) What accounts for the stability of the sn-glycero-1- phosphate isomer of BMP in cells 4) Where the precursor phosphatidylglycerol is localized in the macrophage 50 Where the enzymes of BMP metabolism are localized in the cell Many of the proposed studies will employ the model macrophage cell line RAW 264.7. All key observations will be verified using human alveolar macrophages so that we can determine the route of BMP metabolism in human lung. Considerable emphasis will be placed on determining the relative contribution to two pathways for BMP synthesis that lead to the formation of different stereoisomers. Since only one isomer (sn-glycero-1-phosphoryl-sn-1'- glycerol) accumulates, we believe that phospholipases in the macrophages selectively degrade the other (sn-glycero- 3-phosphoryl-sn-3-glycerol) isomer formed. We also will test the hypothesis that the endosomal pathway is involved in phosphatidyl-glycerol uptake and conversion to BMP. These studies, therefore, should establish the mechanisms of BMP metabolism including the route of entry of the precursor molecule into the cell. We also will determine how the acyl groups are turned over emphasizing the significance of arachidonate removal that may relate to eicosanoid synthesis.

肺泡巨噬细胞在肺稳态中起关键作用 和巨噬细胞脂质代谢，与合成 在其脂质介体中，显着影响正常的 病理生理肺功能。 因此，我们的 巨噬细胞脂质代谢的研究对于 了解肺稳态和各种肺 功能障碍。 BIS（单酰基甘油）磷酸盐（BMP） 占肺泡巨噬细胞中18％的磷脂。 这种磷脂在真核组织中是独一无二的 Sn-甘油1-磷酸甘油-SN-1'-甘油立体化合物 这与通常的SN-甘油-3-磷酸-SN-- 在所有其他磷脂中发现的1'-甘油异构体。 但是，有证据表明SN-甘油-3-磷酸磷酸 SN-1'Glycerol也已合成，但不会累积 在巨噬细胞中。 BMP来自外源性 来自肺表面活性剂的磷脂酰甘油，含有高 包括蛛网膜化的不饱和脂肪酸的水平 可以参与类类合成的酸。 为了 我们建议研究的这些原因： 1）两个BMP异构体是 合成 2）如何在BMP中转动脂肪酸 3）什么是SN-甘油-1-的稳定性的原因 细胞中BMP的磷酸异构体 4）其中磷脂酰甘油含量是局部的 在巨噬细胞中 50 BMP代谢的酶位于本地化 细胞 许多拟议的研究将采用该模型 巨噬细胞系列264.7。 所有关键观察将 使用人肺泡巨噬细胞进行验证，以便我们可以 确定人类肺中BMP代谢的途径。 重点将放在确定 BMP合成的两种途径的相对贡献 这导致形成不同的立体异构体。 由于只有一个异构体（sn-glycero-1-磷酸-SN-1'-- 甘油）积聚，我们认为磷脂酶 巨噬细胞有选择地降解另一个（SN-甘油 - 形成的3-磷酸-SN-3-甘油）异构体。 我们也会 测试涉及内体途径的假设 在磷脂酰基甘油摄取和转化为BMP中。 因此，这些研究应建立机制 BMP代谢包括进入 前体分子进入细胞。 我们还将确定 如何将酰基群翻过来强调 蛛网除去的意义可能与 类花生酸合成。