title: The anti-inflammatory role of tissue inhibitor of metalloproteinase-2 in lipopolysaccharide-stimulated microglia.
abstract: BACKGROUND
  Tissue inhibitors of metalloproteinases (TIMPs) are known to be endogenous inhibitors of matrix metalloproteinases (MMPs). Our preliminary study showed that TIMP-2 is constitutively expressed in microglia but significantly inhibited by lipopolysaccharide (LPS) treatment. The current study was undertaken to investigate the role of TIMP-2 in microglia.
  
  
  METHODS
  The expression of TIMP-2 was evaluated in the BV2 mouse microglial cell line and rat primary cultured microglia. To investigate the role of TIMP-2, a TIMP-2 expression plasmid or small interfering RNA (siRNA) was introduced into BV2 cells by transient transfection, and their effects on LPS-induced inflammatory reactions were examined. We further analyzed the molecular mechanism underlying the anti-inflammatory effects of TIMP-2 by electrophoretic mobility shift assay (EMSA), a reporter gene assay and Western blot analysis.
  
  
  RESULTS
  Overexpression of TIMP-2 significantly inhibited the production of nitric oxide (NO), TNF-α, IL-1β, and reactive oxygen species (ROS), while increasing anti-inflammatory IL-10 production. On the other hand, knockdown of TIMP-2 augmented the production of pro-inflammatory molecules and downregulated IL-10 in LPS-stimulated BV2 cells. The results suggest that endogenously expressed TIMP-2 plays an anti-inflammatory role. Further mechanistic studies revealed that overexpression of TIMP-2 suppresses microglial activation via inhibition of the activity of mitogen-activated protein kinases (MAPKs) and NF-κB with enhancement of the activity of anti-inflammatory Nrf2 and cAMP-response element binding protein (CREB) transcription factors. TIMP-2 also inhibited the activity and expression of LPS-induced MMP-3, -8, and -9. Finally, we demonstrated that TIMP-2 exerts a neuroprotective effect via the inhibition of microglial activation.
  
  
  CONCLUSIONS
  Enhancement of TIMP-2 expression may be a potential therapeutic target for neuroinflammatory disorders.
authors: Eun-Jung
authors: EJ
authors: Lee
authors: Department of Molecular Medicine and Global Top5 Research Program, Tissue Injury Defense Research Center, School of Medicine, Ewha Womans University, Mok-6-dong 911-1, Yangchun-Ku, 158-710 Seoul, South Korea. hskimp@ewha.ac.kr.
authors: Hee-Sun
authors: HS
authors: Kim
mesh_terms: D000818:Animals; D000831:Animals, Newborn; D050882:CREB-Binding Protein / Q000378:metabolism; D016923:Cell Death / Q000187:drug effects; D002478:Cells, Cultured; D017364:Collagenases / Q000378:metabolism; D016207:Cytokines / Q000235:genetics / Q000378:metabolism; D005786:Gene Expression Regulation / Q000187:drug effects*; D008070:Lipopolysaccharides / Q000494:pharmacology*; D051379:Mice; D017628:Microglia / Q000187:drug effects* / Q000378:metabolism; D020928:Mitogen-Activated Protein Kinases / Q000378:metabolism; D051267:NF-E2-Related Factor 2 / Q000378:metabolism; D009447:Neuroblastoma / Q000473:pathology; D009474:Neurons / Q000187:drug effects / Q000378:metabolism; D009573:Nitrites / Q000378:metabolism; D034741:RNA, Small Interfering / Q000235:genetics / Q000502:physiology; D051381:Rats; D017207:Rats, Sprague-Dawley; D017382:Reactive Oxygen Species / Q000378:metabolism; D019716:Tissue Inhibitor of Metalloproteinase-2 / Q000235:genetics / Q000378:metabolism*
chemical_list: D016207:Cytokines; D008070:Lipopolysaccharides; D051267:NF-E2-Related Factor 2; D009573:Nitrites; D034741:RNA, Small Interfering; D017382:Reactive Oxygen Species; D019716:Tissue Inhibitor of Metalloproteinase-2; D050882:CREB-Binding Protein; D020928:Mitogen-Activated Protein Kinases; D017364:Collagenases