CCR1-mediated activation of Nuclear Factor-kappaB in THP-1 monocytic cells involves Pertussis Toxin-insensitive Galpha(14) and Galpha(16) signaling cascades

J Leukoc Biol. 2009 Dec;86(6):1319-29. doi: 10.1189/jlb.0209052. Epub 2009 Aug 17.

Abstract

Agonists of CC chemokine receptor CCR1 contribute to the pathogenesis of autoimmune and other inflammatory diseases, possibly via the regulation of the transcription factor NF-kappaB. CCR1 and CCR2b have been demonstrated to use PTX-insensitive Galpha(14) and Galpha(16) to stimulate PLCbeta in cotransfected cells, and Galpha(14) and Galpha(16) are capable of activating NF-kappaB. The coexpression of Galpha(14), Galpha(16), and CCR1 in human monocytic THP-1 cells suggests that CCR1 may use Galpha(14) or Galpha(16) to induce NF-kappaB activation. Here, we demonstrated that a CCR1 agonist, Lkn-1, stimulated NF-kappaB phosphorylation via PTX-insensitive G proteins in THP-1 cells. Lkn-1 also mediated IKK/NF-kappaB phosphorylations in HEK293 cells overexpressing CCR1 and Galpha(14/16). Using various kinase inhibitors, Raf-1, MEK1/2, PLCbeta, PKC, CaM, CaMKII, and c-Src were found to participate in Lkn-1-stimulated IKK/NF-kappaB phosphorylations in THP-1 and transfected HEK293 cells. Although c-Jun N-terminal kinase and p38 MAPK were activated by Lkn-1, they were not required in Lkn-1-induced IKK phosphorylation. The ability of CCR1 to signal through Galpha(14/16) thus provides a linkage for chemokines to regulate NF-kappaB-dependent responses.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • GTP-Binding Protein alpha Subunits, Gq-G11 / immunology*
  • Humans
  • Monocytes / immunology*
  • Phosphorylation / drug effects
  • Phosphorylation / immunology
  • Protein Kinase Inhibitors / pharmacology
  • Protein Kinases / immunology
  • Receptors, CCR1 / immunology*
  • Receptors, CCR2 / immunology
  • Signal Transduction / immunology*
  • U937 Cells

Substances

  • CCR1 protein, human
  • Protein Kinase Inhibitors
  • Receptors, CCR1
  • Receptors, CCR2
  • Protein Kinases
  • G protein alpha 16
  • GNA14 protein, human
  • GTP-Binding Protein alpha Subunits, Gq-G11