β-Lapachone suppresses neuroinflammation by modulating the expression of cytokines and matrix metalloproteinases in activated microglia

J Neuroinflammation. 2015 Jul 16;12:133. doi: 10.1186/s12974-015-0355-z.

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.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Anti-Inflammatory Agents / pharmacology*
  • Cell Line
  • Cells, Cultured
  • Cytokines / metabolism*
  • Disease Models, Animal
  • Encephalitis / chemically induced
  • Encephalitis / metabolism*
  • Encephalitis / prevention & control*
  • Heme Oxygenase-1 / metabolism
  • In Vitro Techniques
  • Interleukin-10 / metabolism
  • Lipopolysaccharides / adverse effects
  • Lipopolysaccharides / pharmacology
  • Matrix Metalloproteinases / metabolism*
  • Mice
  • Microglia / drug effects*
  • Microglia / metabolism
  • Naphthoquinones / pharmacology*
  • Nitric Oxide Synthase Type II / metabolism
  • Nitrites / metabolism
  • Rats
  • Rats, Sprague-Dawley
  • Reactive Oxygen Species / metabolism
  • Signal Transduction / drug effects
  • Tissue Inhibitor of Metalloproteinase-2 / metabolism

Substances

  • Anti-Inflammatory Agents
  • Cytokines
  • Lipopolysaccharides
  • Naphthoquinones
  • Nitrites
  • Reactive Oxygen Species
  • Tissue Inhibitor of Metalloproteinase-2
  • Interleukin-10
  • beta-lapachone
  • Nitric Oxide Synthase Type II
  • Heme Oxygenase-1
  • Matrix Metalloproteinases