IL-1β induces MMP-9 via reactive oxygen species and NF-κB in murine macrophage RAW 264.7 cells

Abstract

IL-1β increased the production of proenzyme of MMP-9 (pro-MMP-9) in a time- and dose-dependent manner in murine macrophage RAW 264.7 cells. However, the production of MMP-2 was not significantly changed by IL-1β treatment. The intracellular H 2O 2 content, as determined with H 2O 2-sensitive probe 2 ′,7 ′-dichlorodihydrofluorescein, also increased after IL-1β treatment (5 ng/ml). In addition, exogenous H 2O 2 (50 μM) was found to increase the production of pro-MMP-9. Transient transfection study using a MMP-9 promoter–reporter construct showed that IL-1β enhanced the MMP-9 promoter activity. Electrophoretic mobility shift assay and site-directed mutagenesis study on the consensus binding site for NF-κB revealed that the activation of NF-κB is required for the IL-1β-induced activation of MMP-9 promoter. N-acetylcysteine, an antioxidant, could abrogate the production of pro-MMP-9, H 2O 2 generation, and activation of NF-κB and MMP-9 promoter. These results suggest that IL-1β upregulates the MMP-9 expression via production of reactive oxygen species and activation of NF-κB in RAW 264.7 cells.