title: β-Lapachone suppresses neuroinflammation by modulating the expression of cytokines and matrix metalloproteinases in activated microglia.
abstract: BACKGROUND
  β-Lapachone (β-LAP) is a natural naphthoquinone compound isolated from the lapacho tree (Tabebuia sp.), and it has been used for treatment of rheumatoid arthritis, infection, and cancer. In the present study, we investigated whether β-LAP has anti-inflammatory effects under in vitro and in vivo neuroinflammatory conditions.
  
  
  METHODS
  The effects of β-LAP on the expression of inducible nitric oxide synthase (iNOS), cytokines, and matrix metalloproteinases (MMPs) were examined in lipopolysaccharide (LPS)-stimulated BV2 microglial cells and rat primary microglia by ELISA, reverse transcription polymerase chain reaction (RT-PCR), and Western blot analysis. Microglial activation and the expression levels of proinflammatory molecules were measured in the LPS-injected mouse brain by immunohistochemistry and RT-PCR analysis. The detailed molecular mechanism underlying the anti-inflammatory effects of β-LAP was analyzed by electrophoretic mobility shift assay, reporter gene assay, Western blot, and RT-PCR analysis.
  
  
  RESULTS
  β-LAP inhibited the expression of iNOS, proinflammatory cytokines, and MMPs (MMP-3, MMP-8, MMP-9) at mRNA and protein levels in LPS-stimulated microglia. On the other hand, β-LAP upregulated the expressions of anti-inflammatory molecules such as IL-10, heme oxygenase-1 (HO-1), and the tissue inhibitor of metalloproteinase-2 (TIMP-2). The anti-inflammatory effect of β-LAP was confirmed in an LPS-induced systemic inflammation mouse model. Thus, β-LAP inhibited microglial activation and the expressions of iNOS, proinflammatory cytokines, and MMPs in the LPS-injected mouse brain. Further mechanistic studies revealed that β-LAP exerts anti-inflammatory effects by inhibiting MAPKs, PI3K/AKT, and NF-κB/AP-1 signaling pathways in LPS-stimulated microglia. β-LAP also inhibited reactive oxygen species (ROS) production by suppressing the expression and/or phosphorylation of NADPH oxidase subunit proteins, such as p47(phox) and gp91(phox). The anti-oxidant effects of β-LAP appeared to be related with the increase of HO-1 and NQO1 via the Nrf2/anti-oxidant response element (ARE) pathway and/or the PKA pathway.
  
  
  CONCLUSIONS
  The strong anti-inflammatory/anti-oxidant effects of β-LAP may provide preventive therapeutic potential for various neuroinflammatory disorders.
authors.affiliation: Department of Molecular Medicine, Tissue Injury Defense Research Center, School of Medicine, Ewha Womans University, Mok-6-dong 911-1, Yangchun-Ku, Seoul, 158-710, South Korea. 1sagain@ewhain.net.
authors.forename: Eun-Jung
authors.initials: EJ
authors.lastname: Lee
authors.affiliation: Department of Molecular Medicine, Tissue Injury Defense Research Center, School of Medicine, Ewha Womans University, Mok-6-dong 911-1, Yangchun-Ku, Seoul, 158-710, South Korea. greatman00@hanmail.net.
authors.forename: Hyun-Myung
authors.initials: HM
authors.lastname: Ko
authors.affiliation: Department of Molecular Medicine, Tissue Injury Defense Research Center, School of Medicine, Ewha Womans University, Mok-6-dong 911-1, Yangchun-Ku, Seoul, 158-710, South Korea. jyh4560@ewhain.net.
authors.forename: Yeon-Hui
authors.initials: YH
authors.lastname: Jeong
authors.affiliation: Department of Pharmacology, Tissue Injury Defense Research Center, School of Medicine, Ewha Womans University, Seoul, 158-710, South Korea. empark@ewha.ac.kr.
authors.forename: Eun-Mi
authors.initials: EM
authors.lastname: Park
authors.affiliation: Department of Molecular Medicine, Tissue Injury Defense Research Center, School of Medicine, Ewha Womans University, Mok-6-dong 911-1, Yangchun-Ku, Seoul, 158-710, South Korea. hskimp@ewha.ac.kr.
authors.forename: Hee-Sun
authors.initials: HS
authors.lastname: Kim
mesh_terms: D000818:Animals; D000893:Anti-Inflammatory Agents / Q000494:pharmacology*; D002460:Cell Line; D002478:Cells, Cultured; D016207:Cytokines / Q000378:metabolism*; D004195:Disease Models, Animal; D004660:Encephalitis / Q000139:chemically induced / Q000378:metabolism* / Q000517:prevention & control*; D051547:Heme Oxygenase-1 / Q000378:metabolism; D066298:In Vitro Techniques; D016753:Interleukin-10 / Q000378:metabolism; D008070:Lipopolysaccharides / Q000009:adverse effects / Q000494:pharmacology; D020782:Matrix Metalloproteinases / Q000378:metabolism*; D051379:Mice; D017628:Microglia / Q000187:drug effects* / Q000378:metabolism; D009285:Naphthoquinones / Q000494:pharmacology*; D052247:Nitric Oxide Synthase Type II / Q000378:metabolism; D009573:Nitrites / Q000378:metabolism; D051381:Rats; D017207:Rats, Sprague-Dawley; D017382:Reactive Oxygen Species / Q000378:metabolism; D015398:Signal Transduction / Q000187:drug effects; D019716:Tissue Inhibitor of Metalloproteinase-2 / Q000378:metabolism
chemical_list: D000893:Anti-Inflammatory Agents; D016207:Cytokines; D008070:Lipopolysaccharides; D009285:Naphthoquinones; D009573:Nitrites; D017382:Reactive Oxygen Species; D019716:Tissue Inhibitor of Metalloproteinase-2; D016753:Interleukin-10; C014638:beta-lapachone; D052247:Nitric Oxide Synthase Type II; D051547:Heme Oxygenase-1; D020782:Matrix Metalloproteinases