SIK inhibition in human myeloid cells modulates TLR and IL-1R signaling and induces an anti-inflammatory phenotype

J Leukoc Biol. 2016 May;99(5):711-21. doi: 10.1189/jlb.2A0715-307R. Epub 2015 Nov 20.


Macrophage polarization into a phenotype producing high levels of anti-inflammatory IL-10 and low levels of proinflammatory IL-12 and TNF-α cytokines plays a pivotal role in the resolution of inflammation. Salt-inducible kinases synergize with TLR signaling to restrict the formation of these macrophages. The expression and function of salt-inducible kinase in primary human myeloid cells are poorly characterized. Here, we demonstrated that the differentiation from peripheral blood monocytes to macrophages or dendritic cells induced a marked up-regulation of salt-inducible kinase protein expression. With the use of 2 structurally unrelated, selective salt-inducible kinase inhibitors, HG-9-91-01 and ARN-3236, we showed that salt-inducible kinase inhibition significantly decreased proinflammatory cytokines (TNF-α, IL-6, IL-1β, and IL-12p40) and increased IL-10 secretion by human myeloid cells stimulated with TLR2 and-4 agonists. Differently than in mouse cells, salt-inducible kinase inhibition did not enhance IL-1Ra production in human macrophages. Salt-inducible kinase inhibition blocked several markers of proinflammatory (LPS + IFN-γ)-polarized macrophages [M(LPS + IFN-γ)] and induced a phenotype characterized by low TNF-α/IL-6/IL-12p70 and high IL-10. The downstream effects observed with salt-inducible kinase inhibitors on cytokine modulation correlated with direct salt-inducible kinase target (CREB-regulated transcription coactivator 3 and histone deacetylase 4) dephosphorylation in these cells. More importantly, we showed for the first time that salt-inducible kinase inhibition decreases proinflammatory cytokines in human myeloid cells upon IL-1R stimulation. Altogether, our results expand the potential therapeutic use of salt-inducible kinase inhibitors in immune-mediated inflammatory diseases.

Keywords: dendritic cells; inflammation; macrophages; monocytes.

MeSH terms

  • AMP-Activated Protein Kinase Kinases
  • Cell Polarity / drug effects
  • Gene Knockdown Techniques
  • Histone Deacetylases / metabolism
  • Humans
  • Inflammation / metabolism
  • Inflammation / pathology*
  • Inflammation Mediators / metabolism
  • Interferon-gamma / pharmacology
  • Interleukin-10 / metabolism
  • Interleukin-1beta / pharmacology
  • Lipopolysaccharides / pharmacology
  • Macrophages / drug effects
  • Macrophages / enzymology
  • Monocytes / drug effects
  • Monocytes / enzymology
  • Myeloid Cells / drug effects
  • Myeloid Cells / enzymology*
  • Phenotype
  • Phenylurea Compounds
  • Phosphorylation / drug effects
  • Protein Serine-Threonine Kinases / antagonists & inhibitors*
  • Protein Serine-Threonine Kinases / metabolism
  • Pyrimidines
  • RNA, Small Interfering / metabolism
  • Receptors, Interleukin-1 / metabolism*
  • Repressor Proteins / metabolism
  • Signal Transduction* / drug effects
  • Toll-Like Receptor 2 / agonists
  • Toll-Like Receptor 2 / metabolism*
  • Toll-Like Receptor 4 / agonists
  • Toll-Like Receptor 4 / metabolism*
  • Transcription Factors / metabolism
  • Tumor Necrosis Factor-alpha / metabolism


  • CRTC3 protein, human
  • HG-9-91-01
  • IL10 protein, human
  • Inflammation Mediators
  • Interleukin-1beta
  • Lipopolysaccharides
  • Phenylurea Compounds
  • Pyrimidines
  • RNA, Small Interfering
  • Receptors, Interleukin-1
  • Repressor Proteins
  • Toll-Like Receptor 2
  • Toll-Like Receptor 4
  • Transcription Factors
  • Tumor Necrosis Factor-alpha
  • Interleukin-10
  • Interferon-gamma
  • Protein Serine-Threonine Kinases
  • STK11 protein, human
  • AMP-Activated Protein Kinase Kinases
  • HDAC4 protein, human
  • Histone Deacetylases