文摘
Nitrated fatty acids (nitroalkenes) have been recently detected and quantified in cell membranesand human plasma. However, nitration of arachidonate (AA), that could redirect AA-dependent cellsignaling pathways, has not been studied in detail. Herein, we synthesized and determined for the firsttime the isomer distribution of nitroarachidonate (AANO2) and demonstrate its ability to modulateinflammation. Synthesis of AANO2 was achieved by AA treatment with sodium nitrite in acidic conditionsfollowing HPLC separation. Mass spectrometry (MS) analysis showed the characteristic MS/MS transitionof AANO2 (m/z 348/301). Moreover, the IR signal at 1378.3 cm-1 and NMR studies confirmed the presenceof mononitrated nitroalkenes. Positional isomer distribution was determined by NMR and MS fragmentationwith lithium; four major isomers (9-, 12-, 14-, and 15-AANO2) were identified, which exhibited keyanti-inflammatory properties. These include their ability to release biologically relevant amounts of nitricoxide, induce cGMP-dependent vasorelaxation, and down-regulate inducible nitric oxide synthase (NOS2)expression during macrophage activation, providing unique structural evidence and novel regulatorysignaling properties of AANO2.