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: Eun-Jung Lee, Hyun-Myung Ko, Yeon-Hui Jeong, Eun-Mi Park, Hee-Sun Kim
• Journal: Journal of neuroinflammation (J Neuroinflammation) Vol. 12 Pg. 133 (Jul 16 2015) ISSN: 1742-2094 [Electronic] England
• PMID: 26173397 (Publication Type: Journal Article, Research Support, Non-U.S. Gov't)

Chemical References

• 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

Topics

• Animals
• Anti-Inflammatory Agents (pharmacology)
• Cell Line
• Cells, Cultured
• Cytokines (metabolism)
• Disease Models, Animal
• Encephalitis (chemically induced, metabolism, prevention & control)
• Heme Oxygenase-1 (metabolism)
• In Vitro Techniques
• Interleukin-10 (metabolism)
• Lipopolysaccharides (adverse effects, pharmacology)
• Matrix Metalloproteinases (metabolism)
• Mice
• Microglia (drug effects, 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)