Fisetin inhibits osteoclastogenesis through prevention of RANKLInduced ROS production by Nrf2-mediated Up-regulation of Phase II antioxidant enzymes

Eiko Sakai, Megumi Shimada-Sugawara, Yu Yamaguchi, Hiroshi Sakamoto, Reiko Fumimoto, Yutaka Fukuma, Kazuhisa Nishishita, Kuniaki Okamoto, Takayuki Tsukuba

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37 Citations (Scopus)


Osteoclasts (OCLs) are multinucleated bone-resorbing cells that are differentiated by stimulation with receptor activator of nuclear factor kappa-B ligand (RANKL) and macrophage colony-stimulating factor. We recently demonstrated that regulation of heme-oxygenase 1 (HO-1), a stress-induced cytoprotective enzyme, also functions in OCL differentiation. In this study, we investigated effects of fisetin, a natural bioactive flavonoid that has been reported to induce HO-1 expression, on the differentiation of macrophages into OCLs. Fisetin inhibited the formation of OCLs in a dose-dependent manner and suppressed the bone-resorbing activity of OCLs. Moreover, fisetin-treated OCLs showed markedly decreased phosphorylation of extracellular signal-regulated kinase, Akt, and Jun N-terminal kinase, but fisetin did not inhibit p38 phosphorylation. Fisetin up-regulated mRNA expression of phase II antioxidant enzymes including HO-1 and interfered with RANKL-mediated reactive oxygen species (ROS) production. Studies with RNA interference showed that suppression of NF-E2-related factor 2 (Nrf2), a key transcription factor for phase II antioxidant enzymes, rescued fisetin-mediated inhibition of OCL differentiation. Furthermore, fisetin significantly decreased RANKL-induced nuclear translocation of cFos and nuclear factor of activated T cells cytoplasmic-1 (NFATc1), which is a transcription factor critical for osteoclastogenic gene regulation. Therefore, fisetin inhibits OCL differentiation through blocking RANKLmediated ROS production by Nrf2-mediated up-regulation of phase II antioxidant enzymes.

Original languageEnglish
Pages (from-to)288-298
Number of pages11
JournalJournal of Pharmacological Sciences
Issue number4
Publication statusPublished - May 15 2013
Externally publishedYes



  • Fisetin
  • NF-E2-related factor 2 (Nrf2)
  • Nuclear factor of activated T cells cytoplasmic-1 (NFATc1)
  • Osteoclast
  • Reactive oxygen species (ROS)

ASJC Scopus subject areas

  • Molecular Medicine
  • Pharmacology

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