Figure 7

Quercetin decreases MMP9 and MMP12 and increases Sirt1 in LPS-treated alveolar macrophages. Mouse alveolar macrophages were treated with LPS (1 ng/ml) for 3 days and treated with DMSO (vehicle) or 25 µM quercetin for 16 h. A and B. LPS treatment induced mRNA expression of MMP9 and MMP12 which are partially reversed by quercetin. C and E. Quercetin increases Sirt1 mRNA and protein expression. D. MMP9 activity in LPS-exposed was abrogated by quercetin treatment. E. A representative Western blot showing Sirt1 and β-actin expression. F. Ratio of Sirt1 protein/β-actin normalized to untreated cells calculated from 3 independent experiments. G and H. Quercetin decreased LPS-induced histone H4 acetylation at the NF-κB binding sites in the promoter regions of both Mmp9 and Mmp12. Zymogram and immunoblot images are representative of three independent experiments. Data represent mean and SEM calculated from 3 independent experiments performed in duplicates or triplicates (*different from macrophages exposed to media in the absence of quercetin, p≤0.05; †different from LPS-exposed macrophages which are not treated with quercetin, p≤0.05 one-way ANOVA).