Cell culture and viability analysis
The Raw264.7 cell line (Cell Resource Center of the Shanghai Institutes for Biological Sciences (TIB-71), China) is a normal mouse macrophage cell line. The Raw264.7 cell line is a type of adherent cell that was cultured in DMEM (Shanghai Reith Biotechnology Co., Ltd., China) supplemented with 10% FBS (Gibco, 10099-141, USA) in an incubator at 37 °C with 5% CO2. Cell viability was measured by the CCK-8 assay, live-dead cell staining and cell apoptosis assay. For the CCK-8 assay, Raw264.7 cells were seeded overnight in 96-well plates at a density of 5 × 104 cells/well. Then, the medium was changed to medium with 10% FBS containing different percentages of P.g(109 CFU) culture medium (from 1% (1%-P.g ) to 10% (10%-P.g ) by volume) and incubated for 24 h (the total volume of this mixture was 3 ml, and the control group was supplemented with cell culture medium containing fresh BHI medium). CCK-8 solution (10 µl/well) (Shanghai Reith Biotechnology Co., Ltd., China) was added and incubated for 90 min at room temperature, and then the 96-well plate was placed in a microplate spectrophotometer to measure the absorption value at 450 nm. For live-dead cell staining, after the Raw264.7 cells were seeded in 6-well plates at a density of 1 × 106cells/well overnight, they were cultured with 5% P.g for 24 h. Cell viability was determined using the Live-Dead Cell Staining Kit (Vazyme Biotech Co., Ltd., China) in accordance with the manufacturer’s instructions. Images were captured with a Carl Zeiss LSM710 fluorescence microscope. The SV40-MES-13 cell line (Cell Resource Center of the Shanghai Institutes for Biological Sciences (CRL-1927), China) is a normal mouse glomerular mesangial cell line. The SV40-MES-13 cell line was cultured in DMEM/F12 medium (Shanghai Reith Biotechnology Co., Ltd., China) supplemented with 10% FBS (Gibco, 10099-141, USA) in an incubator at 37 °C with 5% CO2. Cell viability was measured as previously described. For the CCK-8 assay, SV40-MES-13 cells were seeded in 96-well plates at a density of 5 × 104 cells/well overnight. Then, the cell culture medium was changed to medium containing 10% FBS containing 50% (by volume) and the supernatant of RAW264.7 cells stimulated with 5% P.g (macrophage-conditioned medium, MΦCM) for 24 h (the total volume was 3 ml, and the control group was supplemented with the supernatant of RAW264.7 cells without P.gstimulation). CCK-8 solution (10 µl/well) (Shanghai Reith Biotechnology Co., Ltd., China) was used to assess the viability of the cells. After being incubated for 90 min at room temperature, the 96-well plate was placed in a microplate spectrophotometer to measure the absorption value at 450 nm. After SV40-MES-13 cells were seeded in 6-well plates at a density of 1 × 106 cells/well overnight, they were cultured with MΦCM for 24 h. For live-dead cell staining, viability was determined using the Live/Dead Cell Staining Kit (Vazyme Biotech Co., Ltd., China) in accordance with the manufacturer’s instructions. Images were captured with a Carl Zeiss LSM710 fluorescence microscope.