Anti-inflammatory Mechanism of Ginseng Saponin Metabolite Rh3 in Lipopolysaccharide-Stimulated Microglia: Critical Role of 5′-Adenosine Monophosphate-Activated Protein Kinase Signaling Pathway

Yu Young Lee, Jin Sun Park, Eun Jung Lee, Sang Yun Lee, Dong Hyun Kim, Jihee Lee Kang, Hee Sun Kim

Research output: Contribution to journalArticlepeer-review

67 Scopus citations

Abstract

Ginsenoside Rh3 is a bacterial metabolite of Rg5, which is the main constituent of heat-processed ginseng. The present study was undertaken to examine the anti-inflammatory effect of ginsenoside Rh3 in lipopolysaccharide (LPS)-stimulated microglia. Rh3 inhibits the expressions of inducible nitric oxide synthase (iNOS) and proinflammatory cytokines, such as tumor necrosis factor (TNF)-α and interleukin (IL)-6, at mRNA and protein levels, while Rh3 enhanced anti-inflammatory hemeoxygenase-1 expression. Moreover, Rh3 inhibited nuclear factor-κB (NF-κB) by upregulation of sirtuin 1 (SIRT1) and enhanced Nrf2 DNA-binding activities. Analysis of signaling pathways revealed that Rh3 enhanced the phosphorylation of 5′-adenosine monophosphate-activated protein kinase (AMPK) and inhibited Akt and janus kinase 1 (JAK1)/signal transducer and activator of transcription 1 (STAT1) induced by LPS. By treatment of BV2 cells with AICAR (a pharmacological activator of AMPK), we found that AMPK is an upstream regulator of phosphatidylinositol 3-kinase (PI3K)/Akt and JAK1/STAT1. Furthermore, AMPK knockdown experiments demonstrated the anti-inflammatory role of AMPK in LPS/Rh3-treated BV2 microglia. Our data collectively suggest that Rh3 exerts an anti-inflammatory effect in microglia by modulating AMPK and its downstream signaling pathways.

Original languageEnglish
Pages (from-to)3472-3480
Number of pages9
JournalJournal of Agricultural and Food Chemistry
Volume63
Issue number13
DOIs
StatePublished - 23 Mar 2015

Bibliographical note

Publisher Copyright:
© 2015 American Chemical Society.

Keywords

  • AMPK
  • Ginsenoside Rh3
  • Microglia
  • Neuroinflammation
  • Signaling molecules

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