Fig. 6

PPARα depletion impairs the antibacterial immune response of A10-PPARα-Cre mice. A–C In vitro phagocytosis. TPMs were incubated with FITC-labeled heat-killed S. aureus (HK-SA-FITC) at 37 °C for 2 h. Bacterial phagocytosis was analyzed via fluorescence microscopy and flow cytometry. A Representative fluorescence microscopy images of the incorporated HK-SA-FITC (green spots) in the TPM (bar = 10 μm). Representative histograms (B) and MFI values (fold change) (C) of incorporated HK-SA-FITC signals in TPMs. D, E Cell surface receptor expression in TPMs. Representative histograms (D) and MFI values (fold change) (E) of CD16/CD32, CD64, CR1/2, TLR2, and TLR6 are shown. F In vitro TPM stimulation assay. TPMs were stimulated with HK-SA at 37 °C for 24 h, and the concentrations of IL-1β, TNF-α, and nitrite in the culture medium were measured via ELISA and the Griess assay. ROS production in TPMs was measured by flow cytometry with DCFDA staining. G, H In vitro MRSA killing. G In vitro bactericidal activity assay. TPMs (1.0 × 10⁶/mL) were incubated with MRSA (1.0 × 10⁷ CFU/mL, MOI = 1:10) for 2 h or 5 h, and the number of live MRSA in the supernatant and within the TPM was quantitated as colony-forming units (CFUs). The bacterial CFUs in the supernatant and intracellular mixture are shown in (H). I–K In vivo MRSA infection. I In vivo bactericidal activity assay. The mice received an i.v. injection of live MRSA (100 μL of 1.0 × 10⁹ CFU/mL in PBS). After 24 h or 48 h, the number of MRSA CFUs in the peripheral blood (PB) was measured (J). The number of MRSA CFUs in the spleen, liver, and lung was also measured at 48 h (per 100 mg of tissue) (K). All MFI values are represented as fold changes (the average value of WT was used as 1). The cumulative data are shown as the means ± SEMs of six or eight samples from two or three independent experiments. One-way ANOVA was used to analyze the data for significant differences. *p < 0.05, **p < 0.01 and ***p < 0.01. ns not significant