Leukotriene b4 d4

Reagents were obtained from the following sources: CBD from THC Pharm GmbH (Frankfurt, Germany); 8-iso prostaglandin F_2α-d4 (8-isoPGF_2α–d4), anandamide-d8 (AEA-d8), 2-arachidonylglycerol-d8 (2-AG-d8), oleoylethanolamide-d4 (OEA-d4), cannabidol-d9 (CBD-d9), leukotriene B4-d4 (LTB4-d4), 5(S)-hydroxy-5Z,8Z,11Z,13E-eicosatetraenoic-5,6,8,9,11,12,14,15-d8 acid (15-HETE-d8) and prostaglandin D2-d4 (PGD2-d4) from Cayman Chemical Company (Ann Arbor, MI, USA); α-tocopherol, retinol, L-glutathione reduced (GSH), glutathione peroxidase (GSH-Px), glutathione reductase (GSSG-R), catalase (CAT), thioredoxin (Trx), β-nicotinamide adenine dinucleotide phosphate hydrate (NADP), β-nicotinamide adenine dinucleotide phosphate, reduced tetra (cyclohexylammonium) salt (NADPH), hexane, butylated hydroxytoluene (BHT), ethanol, O-(2,3,4,5,6-pentafluoro-benzyl) hydroxylamine hydrochloride (PFBHA-HCl), 4-hydroxynonenal (4-HNE) and benzaldehyde-d6 from Sigma-Aldrich (Saint Louis, MO, USA)

Extraction of arachidonate metabolites was performed as described previously16 (link). Subsequently, metabolites were subjected to targeted analysis as described previously17 (link) using a UPLC-5500QTRAP triple quadrupole-linear ion trap hybrid mass spectrometer (AB SCIEX, Framingham, MA). Intensities of ion peaks (areas) were normalized to internal standards (Leukotriene B₄-d4, Cayman Chemical, Ann Arbor, MI), which were added to liver homogenate before metabolite extraction.

Optima grade methanol (MeOH), acetonitrile (ACN), isopropanol (ISP), and acetic acid (AcOH, > 98% pure) were purchased from Fisher Scientific (Pittsburg, PA, USA). UHPLC-grade methyl tert-butyl ether (MTBE) and hexane were also purchased from Fisher Scientific (Pittsburg, PA, USA). Methyl formate (> 98% pure) was purchased from Acros Organics (Morris Plains, NJ, USA). Ammonium acetate (NH₄OAc) was purchased from Fisher Scientific (Fair Lawn, NJ, USA). Deionized water was obtained through filtration via a Millipore Q-Plus (Elix^®35, Molsheim, France). For study 1, native SPM standards: resolvin D1 (RvD1), resolving D2 (RvD2), resolving D3 (RvD3), resolvin D5 (RvD5), resolving E1 (RvE1), maresin (MaR1), and protectin (PD1), and deuterated SPM standards: resolvins (RvD1-d₅, RvD2-d₅, RvD3-d₅, RvE1-d₄) maresin (MaR1-d₅), and leukotriene B4-d₄ were purchased from Cayman Chemicals (Ann Arbor, MI, USA). C18 SPE cartridges (Supel^TM-Select HLB SPE 30 mg loading, 1 mL volume) were purchased from Supelco Analytical (Bellefonte, PA, USA). For study 2, lipid standards were purchased from Cayman Chemical (Ann Arbor, MI, USA), Santa cruz Biotechnology, Inc (Dallas, TX, USA) and Avanti polar Lipids, Inc (Alabaster, AL, USA), as summarized in Supplementary Materials: Table S1.