Leptin

For chemogenetic manipulations, CNO (Enzo Life Sciences) was dissolved in sterile distilled water. For the HFD intake experiments, mice were administered with CNO (2 mg per kg body weight, i.p.) or an equivalent volume of distilled water right before subjecting them to either HFD or Re-HFD. HFD intake was monitored for 2.5 h after CNO administration. For NC intake experiments, CNO (2 mg per kg body weight, i.p.) was administered either when NC was presented back after a 5-h food deprivation or during the basal state. Total NC intake levels were measured for 2.5 h after CNO administration. In the experiments analyzing pSTAT3 levels, leptin (Tocris Bioscience) was dissolved in sterile saline. Mice received an i.p. injection of leptin (1 mg per kg body weight) or saline 1 h before transcardial perfusion.

Antibiotics (penicillin, streptomycin, gentamycin, vancomycin, amphotericin, and ceftazidim), DMSO, L-glutamine, heat-inactivated fetal calf serum (FCS), protease (bovine pancreas) and HEPES were purchased from Sigma^® (St. Louis, MO, USA). Roswell Park Memorial Institute (RPMI) 1640 medium, Dulbecco's Modified Eagle's medium (DMEM) High Glucose medium, and bovine serum albumin were obtained from Eurobio Biotechnology^® (Les Ulis, France). Bronchial epithelial cell growth medium (BEGM, with growth factors and antibiotics) and Mycozap^® were purchased from Lonza^® (Basel, Switzerland). Trypsin 0.25% EDTA was obtained from Gibco^® (ThermoFisher Scientific, Waltham, MA, USA). Culture flasks for epithelial cell culture were from TPP^®, and pre-coated culture flasks were from Corning^® (NY, USA). All the other cell culture plastics were from CML (Nemours, France).
Human recombinant TNF-α was bought from Bio-Techne^® (Lille, France). High-molecular-weight poly(I:C) was obtained from InvivoGen^® (Toulouse, France). Full-length human recombinant adiponectin (produced in E. coli) was purchased from Biovendor^® (Karasek, Czech Republic), and was solubilized in RPMI. Human recombinant Leptin, visfatin and chemerin were also E. coli-derived. Leptin and chemerin were purchased from Bio-Techne^® (Lille, France), and visfatin was purchased from PeproTech^® (Neuilly-sur-Seine, France).

For cell culture experiments the non-adherent monocyte cell line THP-1 (Tohoku Hospital Pediatrics-1)^{17 (link)} was used. Cell culture was performed in RPMI 1640 medium supplemented with 10% heat inactivated fetal bovine serum (FBS), 1% sodium pyruvate and 1% streptomycin/penicillin at 37 °C and 5% CO₂ under a humidified atmosphere. Cells were subcultured every 3 days when they reached a maximum density of 1 × 10⁶ cells/ml. For condition of intermittent hypoxia (5% O₂), cells were incubated in a humidified incubator (Heracell Vios 160i Co2-Incubator, Thermo scientific, Waltham, MA, USA) at 37 °C for 24 h. Further, THP-1 cells were incubated with Leptin (25 µg/ml) and tumor necrosis factor α (TNFα) (10 ng/ml) (Bio-Techne GmbH, Wiesbaden, Germany) for 24 h, respectively.