Obovatol attenuates microglia-mediated  neuroinflammation by modulating redox regulation.
OBJECTIVE
Obovatol isolated from the medicinal herb Magnolia obovata exhibits a variety of biological activities. Here, the effect of obovatol and its mechanism of action on microglial activation, neuroinflammation and neurodegeneration were investigated.


METHODS
In microglial BV-2 cells stimulated with lipopolysaccharide (LPS), we measured nitric oxide (NO) and cytokine production, and activation of intracellular signalling pathways by reverse transcription-polymerase chain reaction and Western blots. Cell death was assayed in co-cultures of activated microglia (with bacterial LPS) and neurons and in LPS- induced neuroinflammation in mice in vivo.


RESULTS
Obovatol inhibited microglial NO production with an IC50 value of 10 mM. Obovatol also inhibited microglial expression of proinflammatory cytokines and inducible nitric-oxide synthase, which was accompanied by the inhibition of multiple signalling pathways such as nuclear factor kappa B, signal transducers and activators of transcription 1, and mitogen-activated protein kinases. In addition, obovatol protected cultured neurons from microglial toxicity and inhibited neuroinflammation in mice in vivo. One molecular target of obovatol in microglia was peroxiredoxin 2 (Prx2), identified by affinity chromatography and mass spectrometry. Obovatol enhanced the reactive oxygen species (ROS)-scavenging activity of Prx2 in vitro, thereby suppressing proinflammatory signalling pathways of microglia where ROS plays an important role.


CONCLUSIONS
Obovatol is not only a useful chemical tool that can be used to investigate microglial signalling, but also a promising drug candidate against neuroinflammatory diseases. Furthermore, our results indicate that Prx2 is a novel drug target that can be exploited for the therapeutic modulation of neuroinflammatory signalling.
Ock
Jiyeon
J
Department of Pharmacology, Brain Science and Engineering Institute, CMRI, Kyungpook National University, Daegu, Korea.
Han
Hyung S
HS
Hong
Su H
SH
Lee
So Y
SY
Han
Young-Min
YM
Kwon
Byoung-Mog
BM
Suk
Kyoungho
K
D000818:Animals; D001713:Biphenyl Compounds / Q000494:pharmacology*; D015153:Blotting, Western; D002460:Cell Line; D018920:Coculture Techniques; D017077:Culture Media, Conditioned; D015180:Electrophoresis, Gel, Two-Dimensional; D004797:Enzyme-Linked Immunosorbent Assay; D005434:Flow Cytometry; D007249:Inflammation / Q000139:chemically induced / Q000473:pathology*; D008070:Lipopolysaccharides / Q000633:toxicity; D051379:Mice; D008813:Mice, Inbred ICR; D017628:Microglia / Q000187:drug effects* / Q000378:metabolism / Q000473:pathology; D009569:Nitric Oxide / Q000096:biosynthesis; D020411:Oligonucleotide Array Sequence Analysis; D010084:Oxidation-Reduction; D010647:Phenyl Ethers / Q000494:pharmacology*; D020133:Reverse Transcriptase Polymerase Chain Reaction
D001713:Biphenyl Compounds; D017077:Culture Media, Conditioned; D008070:Lipopolysaccharides; D010647:Phenyl Ethers; D009569:Nitric Oxide; C036795:obovatol
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