Zacherl Janelle R, Mihalik Stephanie J, Chace Donald H, Christensen Tyson C, Robinson Lisa J, Blair Harry C
Department of Pathology, University of Pittsburgh, Pittsburgh, Pennsylvania, 15261.
J Cell Biochem. 2014 Jan;115(1):62-70. doi: 10.1002/jcb.24633.
Consumption of trans-unsaturated fatty acids promotes atherosclerosis, but whether degradation of fats in macrophages is altered by trans-unsaturated fatty acids is unknown. We compared the metabolism of oleate (C18:1Δ9-10 cis; (Z)-octadec-9-enoate), elaidate (C18:Δ9-10 trans; (E)-octadec-9-enoate), and stearate (C18:0, octadecanoate) in adherent peripheral human macrophages. Metabolism was followed by measurement of acylcarnitines in cell supernatants by MS/MS, determination of cellular fatty acid content by GC/MS, and assessment of β-oxidation rates using radiolabeled fatty acids. Cells incubated for 44 h in 100 µM elaidate accumulated more unsaturated fatty acids, including both longer- and shorter-chain, and had reduced C18:0 relative to those incubated with oleate or stearate. Both C12:1 and C18:1 acylcarnitines accumulated in supernatants of macrophages exposed to trans fats. These results suggested β-oxidation inhibition one reaction proximal to the trans bond. Comparison of [1-(14)C]oleate to [1-(14)C]elaidate catabolism showed that elaidate completed the first round of fatty acid β-oxidation at rates comparable to oleate. Yet, in competitive β-oxidation assays with [9,10-(3)H]oleate, tritium release rate decreased when unlabeled oleate was replaced by the same quantity of elaidate. These data show specific inhibition of monoenoic fat catabolism by elaidate that is not shared by other atherogenic fats.
反式不饱和脂肪酸的摄入会促进动脉粥样硬化，但巨噬细胞中脂肪的降解是否会因反式不饱和脂肪酸而改变尚不清楚。我们比较了粘附的外周血人类巨噬细胞中油酸（C18:1Δ9-10顺式；(Z)-十八碳-9-烯酸）、反油酸（C18:Δ9-10反式；(E)-十八碳-9-烯酸）和硬脂酸（C18:0，十八烷酸）的代谢情况。通过MS/MS测量细胞上清液中的酰基肉碱、通过GC/MS测定细胞脂肪酸含量以及使用放射性标记脂肪酸评估β-氧化速率来跟踪代谢情况。在100μM反油酸中孵育44小时的细胞积累了更多的不饱和脂肪酸，包括长链和短链的，并且相对于用油酸或硬脂酸孵育的细胞，C18:0减少。C12:1和C18:1酰基肉碱在暴露于反式脂肪的巨噬细胞上清液中均有积累。这些结果表明β-氧化在反式键近端的一个反应中受到抑制。[1-(14)C]油酸与[1-(14)C]反油酸分解代谢的比较表明，反油酸完成第一轮脂肪酸β-氧化的速率与油酸相当。然而，在与[9,10-(3)H]油酸的竞争性β-氧化试验中，当未标记的油酸被等量的反油酸取代时，氚释放速率降低。这些数据表明反油酸对单烯脂肪分解代谢有特异性抑制作用，而其他致动脉粥样硬化脂肪则没有这种作用。
