Figure 3.

SIRT1 mediates the effects of PPAR-δ and -γ in the inhibition of LPS-primed release of HMGB1 through deacetylation. (a) RAW 264.7 cells grown to 60% confluency were incubated with serum-free medium for 24 h and then stimulated with LPS for the indicated times. (b) Cells incubated for 24 h in serum-free medium were stimulated with LPS for 6 h in the presence or absence of the ligand indicated. (c and d) Cells were transfected with SIRT1 siRNA and grown for 38 h, after which they were stimulated with LPS for 6 h in the presence or absence of GW501516 (c) or rosiglitazone (d). Whole-cell lysates were immunoprecipitated with anti-HMGB1, and then acetylated HMGB1 was detected by western blotting with an anti–acetyl-lysine antibody. An image analyzer was used to quantitate band intensity, and the ratios of acetylated HMGB1 to total HMGB1 are shown. The results are expressed as means±S.E.M. (n=3). *P<0.05 compared with the untreated group; ^#P<0.05 compared with the LPS-treated group; ^†P<0.05 compared with the group treated with LPS+GW501516 or rosiglitazone