Inhibition of MMP-3 or -9 suppresses lipopolysaccharide-induced expression of proinflammatory cytokines and iNOS in microglia.
Recently, matrix metalloproteinases (MMPs) are emerging as important molecules in neuroinflammation as well as neuronal cell death. However, the role of MMPs in activated microglia remains unclear. In the present study, we found that expressions of MMP-1, -3, -8 and -9 were significantly induced by single or combined treatment of immunostimulants lipopolysaccharide (LPS) or phorbol myristate acetate (PMA) in primary cultured microglia and BV2 microglial cells. Inhibition of MMP-3 or -9 significantly suppressed the expression of iNOS and pro-inflammatory cytokines and the activities of NF-kappaB, AP-1, and MAPK in LPS-stimulated microglia. The results suggest that MMP-3 and -9 both mediate LPS-induced inflammatory reactions. Inhibition of reactive oxygen species (ROS) by N-acetyl-cysteine or diphenylene iodonium significantly suppressed the expression of MMP-3, MMP-9, NO and TNF-alpha in LPS-stimulated microglia, suggesting that ROS is an early signaling inducer in LPS-stimulated microglial cells. MMP inhibitors also suppressed ROS production, suggesting a cross-talk between ROS and MMPs. Collectively, the present study demonstrates that MMP-3 and MMP-9 play a role as inflammatory mediators in activated microglia. Pharmacological intervention of MMPs especially MMP-3 and -9 would be a therapeutic strategy for the treatment of inflammatory diseases in the CNS caused by over-activation of microglial cells.
Woo
Moon-Sook
MS
Department of Neuroscience and Medical Research Institute, School of Medicine, Ewha Womans University, Seoul, South Korea.
Park
Jin-Sun
JS
Choi
In-Young
IY
Kim
Won-Ki
WK
Kim
Hee-Sun
HS
D000818:Animals; D000831:Animals, Newborn; D002478:Cells, Cultured; D002540:Cerebral Cortex / Q000166:cytology; D016207:Cytokines / Q000235:genetics / Q000378:metabolism*; D024202:Electrophoretic Mobility Shift Assay / Q000379:methods; D004789:Enzyme Activation / Q000187:drug effects; D004791:Enzyme Inhibitors / Q000494:pharmacology; D015971:Gene Expression Regulation, Enzymologic / Q000187:drug effects*; D008070:Lipopolysaccharides / Q000494:pharmacology*; D019278:Matrix Metalloproteinase 3 / Q000378:metabolism*; D020780:Matrix Metalloproteinase 9 / Q000378:metabolism*; D051379:Mice; D017628:Microglia / Q000187:drug effects*; D052247:Nitric Oxide Synthase Type II / Q000235:genetics / Q000378:metabolism*; D009573:Nitrites / Q000378:metabolism; D051381:Rats; D017207:Rats, Sprague-Dawley; D017382:Reactive Oxygen Species / Q000378:metabolism; D015398:Signal Transduction / Q000187:drug effects; D013755:Tetradecanoylphorbol Acetate / Q000494:pharmacology; D014162:Transfection / Q000379:methods
D016207:Cytokines; D004791:Enzyme Inhibitors; D008070:Lipopolysaccharides; D009573:Nitrites; D017382:Reactive Oxygen Species; D052247:Nitric Oxide Synthase Type II; D019278:Matrix Metalloproteinase 3; D020780:Matrix Metalloproteinase 9; D013755:Tetradecanoylphorbol Acetate