Ifn γ and il 4

RAW264.7, a macrophage cell line, was cultured in Dulbecco’s minimum essential medium (DMEM; HyClone, Logan, USA) added with 10% fetal bovine serum (FBS; Gibco, New York, USA), 100 U/ml penicillin (Gibco, New York, USA), and 100 μg/ml streptomycin (Gibco, New York, USA). ATDC5, a chondrogenic cell line, was cultured in DMEM: nutrient mixture F12 (DMEM: F12; HyClone, Logan, USA) supplemented with 5% FBS. The cells were placed at 37 °C under humidified conditions with 5% CO₂. The bacterial LPS of Escherichia coli and the recombinant mouse IFN-γ and IL-4 were purchased from PeproTech (Rocky Hill, USA). Exosome-depleted FBS was bought from System Biosciences (California, USA).

L-tryptophan, L-alanine, LPS (Escherichia coli 055:B5), 1-methyl-L-tryptophan (L-1-MT), 1-methyl-D-tryptophan (D-1-MT), diphenylene iodonium (DPI), HPLC-grade methanol (MeOH), and polybrene were obtained from Sigma–Aldrich (St. Louis, MO). IFN-γ and IL-4 were from PeproTech. All primers were synthesized by Sangon Biotech. Anti-IL-10Rα blocking antibody was from R&D Systems (Minneapolis, MN, USA). Mouse anti-IL4I1 monoclonal antibody was generated by AbMart (www.ab-mart.com.cn). Anti-β-actin and Glyceraldehyde 3-phosphate dehydrogenase (GADPH) monoclonal antibodies were also from AbMart. Rabbit monoclonal anti-Myc epitope-tagged antibody, and phospho-STAT6 (Tyr641), phospho-STAT3 (Tyr705), total STAT-3, and total STAT-6 monoclonal antibodies were from Cell Signaling Technologies (Danvers, MA, USA). Anti-mouse CD11b (M1/70), anti-mouse Ly-6G (1A8), anti-mouse F4/80 (BM8), anti-mouse MHC Class II (M5/114.15.2), anti-mouse CD80 (16-10A1), and anti-mouse CD86 (GL1) antibodies were from eBioscience. Ovalbumin (OVA)_323–339 peptide was from Chinese Peptide Co.