Novel regulation of CCL2 gene expression by murine LITAF and STAT6B

PLoS One. 2011;6(9):e25083. doi: 10.1371/journal.pone.0025083. Epub 2011 Sep 28.

Abstract

Inflammation is a multifaceted process: beneficial as a defense mechanism but also detrimental depending on its severity and duration. At the site of injury, inflammatory cells are activated by a cascade of mediators, one of which is LITAF, a transcription regulator known to upregulate TNF-α. We previously showed that human LITAF forms a complex with human STAT6B, which translocates into the nucleus to upregulate cytokine transcription. To dissect the molecular implications of this complex, a murine model was developed and interactions between mouse STAT6B (mSTAT6B) and mouse LITAF (mLITAF) were analyzed. Both mLITAF and mSTAT6B expression were MyD88- and TLR ligand-dependent. Furthermore, mLITAF was found to mediate LPS-induced CCL2 gene transcription with the cooperation of mSTAT6B leading to CCL2 protein expression. In LITAF-deficient mice, mLITAF-mediated CCL2 production in macrophages was significantly reduced compared to the wild-type control animals. Mice knockdown for mSTAT6B by 6BsiRNA1 tail vein injection resulted in a decrease in serum TNF-α and CCL2 production. mLITAF/mSTAT6B complex is proposed to play a role in LPS-induced CCL2 expression and possibly other cytokines.

Publication types

  • Research Support, N.I.H., Extramural

MeSH terms

  • Animals
  • Blotting, Western
  • Cell Line
  • Cell Nucleus / metabolism
  • Chemokine CCL2 / genetics
  • Chemokine CCL2 / metabolism*
  • Chromatin Immunoprecipitation
  • DNA-Binding Proteins
  • Electrophoretic Mobility Shift Assay
  • Enzyme-Linked Immunosorbent Assay
  • Immunoprecipitation
  • Mice
  • Mice, Inbred C57BL
  • Mice, Mutant Strains
  • Nuclear Proteins / genetics
  • Nuclear Proteins / metabolism*
  • Protein Binding / genetics
  • Protein Binding / physiology
  • RNA, Small Interfering
  • STAT6 Transcription Factor / genetics
  • STAT6 Transcription Factor / metabolism*
  • Signal Transduction / genetics
  • Signal Transduction / physiology
  • Toll-Like Receptors / genetics
  • Toll-Like Receptors / metabolism
  • Transcription Factors / genetics
  • Transcription Factors / metabolism*
  • Tumor Necrosis Factor-alpha / metabolism

Substances

  • Ccl2 protein, mouse
  • Chemokine CCL2
  • DNA-Binding Proteins
  • Litaf protein, mouse
  • Nuclear Proteins
  • RNA, Small Interfering
  • STAT6 Transcription Factor
  • Toll-Like Receptors
  • Transcription Factors
  • Tumor Necrosis Factor-alpha