Olive oil

Contact hypersensitivity was induced as described previously.10 Briefly, the abdominal skin of mice was shaved, after which 25 μL of 0.5% (vol/vol) 1‐fluoro‐2,4‐dinitrofluorobenzene (DNFB, Nacalai Tesque) dissolved in a mixture of acetone (Nacalai Tesque) and olive oil (Nacalai Tesque) at a ratio of 4:1 was applied. After 5 days, both sides of the right and left ears were challenged with 0.2% (vol/vol) DNFB (10 μL at each site). After another 2 days, ear thickness was measured using a micrometer (model MDC‐25MJ 293‐230, Mitsutoyo). In order to evaluate the effects of 17,18‐EpETE, mice received racemic compound of 17(S),18(R)‐EpETE and 17(R),18(S)‐EpETE ((±)17,18‐EpETE), a commercially available Cayman (±)17,18‐EpETE (Cayman Chemical). In some experiments, mice were treated with stereoselective 17(S),18(R)‐EpETE (>99% enantiomeric excess) or 17(R),18(S)‐EpETE (>99% enantiomeric excess), which were purified from synthesized (±)17,18‐EpETE, or BM‐3 17(S),18(R)‐EpETE. These lipids were injected intraperitoneally into mice by 100 ng/animal at 30 minutes before DNFB treatment. In some experiments, BM‐3 17(S),18(R)‐EpETE were injected intraperitoneally into mice by 1 µg, 100 ng, or 10 ng/animal in order to evaluate dose response. We used 0.5% (vol/vol) ethanol dissolved in PBS (Nacalai Tesque) as a vehicle control.

C57BL/6 (Clea Japan, Tokyo, Japan), Alb-Cre (The Jackson Laboratory, Bar Harbor, ME)^{41 (link)}, Alb-CreER^T2 (a gift from Drs. Pierre Chambon and Daniel Metzger)^{20 (link)}, R26R^YFP/YFP (a gift from Dr. Frank Costantini)^{21 (link)}, Fah^-/- (RBRC05362) (RIKEN, Japan)^{19 (link)}, NSG (NOD.Cg-Prkdc^scidIl2rg^tm1Wjl/SzJ) (Charles River Laboratories, Wilmington, MA), and Tgfbr2^fl/fl (a gift from Dr. Jürgen Roes)^{42 (link)} mice were used in this study. For induction of Cre activity, male mice (8 week-old) were given a single intraperitoneal injection of TM (7.5 mg/mouse; Sigma-Aldrich, St. Louis, MO) dissolved in olive oil (Nacalai Tesque, Kyoto, Japan) at a concentration of 50 mg/mL. TM was injected 2 weeks before isolation of hepatocytes. Mice were housed in groups of 2–4 per cage in a 12-h light/dark cycle (08:00–20:00 light; 20:00–08:00 dark), with controlled room temperature (22 ± 4 °C) and relative humidity (60%). The experiments were approved by the Kyushu University Animal Experiment Committee, and the care of the animals was in accordance with institutional guidelines.

For induction of Cre activity, mice (8–10 weeks of age) were given a single subcutaneous injection of TM (7.5 mg/mouse; Sigma-Aldrich) dissolved in olive oil (Nacalai Tesque) at a concentration of 50 mg/ml. To induce liver injury, the mice were provided with drinking water containing TAA (300 mg/l; Wako)8 (link) or a diet containing 0.1% DDC (Sigma-Aldrich)43 (link). For Notch signal inhibition, the mice were given intraperitoneal injections of DAPT (50 mg/kg; Wako) dissolved in dimethyl sulfoxide (Nacalai Tesque)/olive oil (1:9) mixed solvent or vehicle alone daily for 1 week. For Kupffer cell ablation, the mice received a single intravenous injection of 100 or 200 μl of clodronate liposomes (Hygieia Bioscience) or control phosphate-buffered saline (PBS).