MMP9 and infection: Recently, we have demonstrated the upregulation of several inflammatory mediators including MMP-9, cPLA2, COX-2, iNOS, and oxidative stress by various proinflammatory factors such as cytokines (e.g., IL-1β), peptides (e.g., bradykinin (BK) or endothelin-1 (ET-1)), infections (e.g., bacteria or virus), and peroxidants (e.g., oxidized low-density lipoprotein (oxLDL)) in rat brain astrocytes [21–29].