Figure 1. Butyrate and propionate, but not acetate, inhibit S. aureus or its lipoprotein-induced NO production in murine macrophages. (A) RAW 264.7 cells (3×105 cells/ml) were treated with 1×108 CFU/ml of live S. aureus in the presence (0.3, 1, or 3 mM) or absence of acetate, propionate, or butyrate for 3 h and further incubated with 200 μg/ml of gentamicin for 21 h. (B) RAW 264.7 cells (3×105 cells/ml) were treated with 50 μg/ml of EKSA in the presence (0.3, 1, or 3 mM) or absence of acetate, propionate, or butyrate for 24 h. (C) RAW 264.7 cells (3×105 cells/ml) were stimulated with 5 μg/ml of Sa.LPP in the presence (0.3, 1, or 3 mM) or absence of acetate, propionate, or butyrate for 24 h. Nitrite in the culture supernatant was measured to determine NO concentration using the Griess reagent. (D) BMDMs (5×105 cells/ml) were stimulated with 5 μg/ml of Sa.LPP in the presence or absence of 3 mM acetate, propionate, or butyrate for 24 h, and nitrite was measured. (E) RAW 264.7 cells (3×105 cells/ml) were treated with 5 μg/ml of Sa.LPP and cultured in the presence (0.3, 1, or 3 mM) or absence of acetate, propionate, or butyrate for 24 h. Cell viability was measured by MTT assay. Data are mean values±standard deviations of 3 independent experiments.
N.D., not detected.
*Asterisks indicate significant differences (p<0.05) compared with the appropriate controls.