Di Marzo V, De Petrocellis L, Sepe N, Buono A
Istituto per la Chimica di Molecole di Interesse Biologico, C.N.R., Naples, Italy.
Biochem J. 1996 Jun 15;316 ( Pt 3)(Pt 3):977-84. doi: 10.1042/bj3160977.
Anandamide (arachidonoylethanolamide, AnNH) has been recently proposed as the endogenous ligand at the brain cannabinoid receptor CB1. Two alternative pathways have been suggested for the biosynthesis of this putative mediator in the central nervous system. Here we present data (1) substantiating further the mechanism by which AnNH is produced by phospholipase D (PLD)-catalysed hydrolysis of N-arachidonoylphosphatidylethanolamine in mouse neuroblastoma N18TG2 cells, and (2) suggesting for the first time that AnNH is biosynthesized via the same mechanism in a non-neuronal cell line, mouse J774 macrophages, together with other acylethanolamides and is possibly involved in the control of the immune/inflammatory response. Lipids from both neuroblastoma cells and J774 macrophages were shown to contain a family of N-acylphosphatidylethanolamines (N-aPEs), including the possible precursor of AnNH, N-arachidonoyl-PE. Treatment with exogenous PLD, but not with exogenous phospholipase A2 and ethanolamine, resulted in the production of a series of acylethanolamides (AEs), including AnNH, from both cell types. The formation of AEs was accompanied by a decrease in the levels of the corresponding N-aPEs. Enzymically active homogenates from either neuroblastoma cells or J774 macrophages were shown to convert synthetic N-[3H]arachidonoyl-PE into [3H]AnNH, thus suggesting that in both cells an enzyme is present which is capable of catalysing the hydrolysis of N-aPE(s) to the corresponding AE(s). Finally, as previously shown in central neurons, on stimulation with ionomycin, J774 macrophages also produced a mixture of AEs including AnNH and palmitoylethanolamide, which has been proposed as the preferential endogenous ligand at the peripheral cannabinoid receptor CB2 and, consequently, as a possible down-modulator of mast cells. On the basis of this as well as previous findings it is now possible to hypothesize for AnNH and palmitoylethanolamide, co-synthesized by macrophages, a role as peripheral mediators with multiple actions on blood cell function.
花生四烯酸乙醇胺（N-花生四烯酰乙醇胺，AnNH）最近被认为是脑内大麻素受体CB1的内源性配体。关于这种假定介质在中枢神经系统中的生物合成，已提出了两条替代途径。在此，我们提供的数据：（1）进一步证实了在小鼠神经母细胞瘤N18TG2细胞中，AnNH是由磷脂酶D（PLD）催化N-花生四烯酰磷脂酰乙醇胺水解产生的机制；（2）首次表明在非神经元细胞系小鼠J774巨噬细胞中，AnNH是通过相同机制与其他酰基乙醇胺一起生物合成的，并且可能参与免疫/炎症反应的调控。神经母细胞瘤细胞和J774巨噬细胞的脂质均显示含有一族N-酰基磷脂酰乙醇胺（N-aPEs），包括AnNH的可能前体N-花生四烯酰-PE。用外源性PLD处理，但不用外源性磷脂酶A2和乙醇胺处理，会导致这两种细胞类型产生一系列酰基乙醇胺（AEs），包括AnNH。AEs的形成伴随着相应N-aPEs水平的降低。来自神经母细胞瘤细胞或J774巨噬细胞的具有酶活性的匀浆显示能将合成的N-[3H]花生四烯酰-PE转化为[3H]AnNH，因此表明在这两种细胞中都存在一种能够催化N-aPE水解为相应AE的酶。最后，正如先前在中枢神经元中所显示的，用离子霉素刺激后，J774巨噬细胞也产生了包括AnNH和棕榈酰乙醇胺的AE混合物，棕榈酰乙醇胺已被认为是外周大麻素受体CB2的优先内源性配体，因此可能是肥大细胞的一种下调调节剂。基于此以及先前的研究结果，现在可以推测由巨噬细胞共同合成的AnNH和棕榈酰乙醇胺作为外周介质对血细胞功能具有多种作用。
