Rapamycin inhibits lipopolysaccharide induction of granulocyte-colony stimulating factor and inducible nitric oxide synthase expression in macrophages by reducing the levels of octamer-binding factor-2

Yuan Yi Chou, Jhen I. Gao, Shwu Fen Chang, Po Yuan Chang, Shao Chun Lu

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17 Citations (Scopus)


This article reports an inhibitory effect of rapamycin on the lipopolysaccharide (LPS)-induced expression of both inducible nitric oxide synthase (iNOS) and granulocyte-colony stimulating factor (G-CSF) in macrophages and its underlying mechanism. The study arose from an observation that rapamycin inhibited the LPS-induced increase in octamer-binding factor-2 (Oct-2) protein levels through a mammalian target of rapamycin (mTOR)-dependent pathway in mouse RAW264.7 macrophages. As both iNOS and G-CSF are potential Oct-2 target genes, we tested the effect of rapamycin on their expression and found that it reduced the LPS-induced increase in iNOS and G-CSF mRNA levels and iNOS and G-CSF protein levels. Blocking of mTOR-signaling using a dominant-negative mTOR expression plasmid resulted in inhibition of the LPS-induced increase in iNOS and G-CSF protein levels, supporting the essential role of mTOR. Forced expression of Oct-2 using the pCG-Oct-2 plasmid overcame the inhibitory effect of rapamycin on the LPS-induced increase in iNOS and G-CSF mRNA levels. Chromatin immunoprecipitation assays showed that LPS enhanced the binding of Oct-2 to the iNOS and G-CSF promoters and that this effect was inhibited by pretreatment with rapamycin. Moreover, RNA interference knockdown of Oct-2 reduced iNOS and G-CSF expression in LPS-treated cells. The inhibitory effect of rapamycin on the LPS-induced increase in Oct-2 protein levels and on the iNOS and G-CSF mRNA levels was also detected in human THP-1 monocyte-derived macrophages. This study demonstrates that rapamycin reduces iNOS and G-CSF expression at the transcription level in LPS-treated macrophages by inhibiting Oct-2 expression.

Original languageEnglish
Pages (from-to)85-96
Number of pages12
JournalFEBS Journal
Issue number1
Publication statusPublished - Jan 2011



  • granulocyte-colony stimulating factor (G-CSF)
  • inducible nitric oxide synthase (iNOS)
  • lipopolysaccharide (LPS)
  • macrophage
  • mammalian target of rapamycin (mTOR)
  • octamer-binding factor-2 (Oct-2)
  • rapamycin

ASJC Scopus subject areas

  • Biochemistry
  • Cell Biology
  • Molecular Biology

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