Arachidonic acid regulates the translocation of 5-lipoxygenase to the nuclear membranes in human neutrophils
Arachidonic acid regulates the translocation of 5-lipoxygenase to the nuclear membranes in human neutrophils
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DOI：
10.1074/jbc.m506513200
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发表时间：
2006-01-06
影响因子：
4.8
通讯作者：
Borgeat, P
中科院分区：
文献类型：
--
作者：
Flamand, N;Lefebvre, J;Borgeat, P
激动剂激活的人中性粒细胞(PMN)内cAMP浓度升高导致花生四烯酸(AA)释放、5-脂氧合酶(5-LO)转位和白三烯(LT)生物合成受到抑制。我们在此报道，外源性AA完全阻止cAMP依赖的对激动剂激活的PMN中5-LO转位和LT生物合成的抑制。此外，IVA磷脂酶A(2)抑制剂吡咯苯酮和MEK抑制剂U-0126抑制活化的PMN中AA的释放和5-LO的移位，这些作用也被外源性AA阻止，这表明AA的释放和5-LO的移位之间存在功能联系。C18和C20系列的多不饱和脂肪酸含有至少三个位于碳9(或更靠近羧基)的双键，在恢复吡咯苯酮激动剂激活的PMN中的5-LO易位方面与AA一样有效。重要的是，用5-LO激活蛋白抑制剂MK-0591和细胞内钙离子螯合剂BAPTA-AM的实验表明，AA调节的5-LO转位是依赖于扇形和钙离子的。最后，氧化还原和竞争性5-LO抑制剂L-685,015、L-739,010和L-702,539(但不是环氧合酶抑制剂)有效地取代AA逆转5-LO转位对吡咯酮的抑制作用，表明AA调节5-LO转位的部位在催化部位或附近。本报告证明了AA调节5-LO在人PMN中的转位，并揭示了cAMP介导的抑制LT生物合成的新机制。
Elevation of the intracellular cAMP concentration in agonist- activated human neutrophils ( PMN) leads to the concomitant inhibitions of arachidonic acid ( AA) release, 5- lipoxygenase ( 5- LO) translocation, and leukotriene ( LT) biosynthesis. We report herein that exogenous AA completely prevents cAMP- dependent inhibition of 5- LO translocation and LT biosynthesis in agonist- activated PMN. Moreover, the group IVA phospholipase A(2) inhibitor pyrrophenone and the MEK inhibitor U- 0126 inhibited AA release and 5- LO translocation in activated PMN, and these effects were also prevented by exogenous AA, demonstrating a functional link between AA release and 5- LO translocation. Polyunsaturated fatty acids of the C18 and C20 series containing at least three double bonds located from carbon 9 ( or closer to the carboxyl group) were equally effective as AA in restoring 5- LO translocation in pyrrophenone- treated agonist- activated PMN. Importantly, experiments with the 5- LO- activating protein inhibitor MK- 0591 and the intracellular Ca2+ chelator BAPTA- AM demonstrated that the AA- regulated 5- LO translocation is FLAP- and Ca2+ dependent. Finally, the redox and competitive 5- LO inhibitors L- 685,015, L- 739,010, and L- 702,539 ( but not cyclooxygenase inhibitors) efficiently substituted for AA to reverse the pyrrophenone inhibition of 5-LO translocation, indicating that the site of regulation of 5- LO translocation by AA is at or in the vicinity of the catalytic site. This report demonstrates that AA regulates the translocation of 5- LO in human PMN and unravels a novel mechanism of the cAMP- mediated inhibition of LT biosynthesis.