MKK3/6-p38 MAPK signaling is required for IL-1beta and TNF-alpha-induced RANKL expression in bone marrow stromal cells

J Interferon Cytokine Res. 2006 Oct;26(10):719-29. doi: 10.1089/jir.2006.26.719.

Abstract

Coupled bone turnover is directed by the expression of receptor-activated NF-kappaB ligand (RANKL) and its decoy receptor, osteoprotegerin (OPG). Proinflammatory cytokines, such as interleukin-1beta (IL-1beta) and tumor necrosis factor-alpha (TNF-alpha) induce RANKL expression in bone marrow stromal cells. Here, we report that IL-1beta and TNF-alpha-induced RANKL requires p38 mitogen-activating protein kinase (MAPK) pathway activation for maximal expression. Real-time PCR was used to assess the p38 contribution toward IL-1beta and TNF-alpha-induced RANKL mRNA expression. Steady-state RANKL RNA levels were increased approximately 17-fold by IL-1beta treatment and subsequently reduced approximately 70%-90% when p38 MAPK was inhibited with SB203580. RANKL mRNA stability data indicated that p38 MAPK did not alter the rate of mRNA decay in IL-1beta-induced cells. Using a RANKL-luciferase cell line receptor containing a 120-kB segment of the 5' flanking region of the RANKL gene, reporter expression was stimulated 4-5-fold by IL-1beta or TNF-alpha treatment. IL-1beta-induced RANKL reporter expression was completely blocked with specific p38 inhibitors as well as dominant negative mutant constructs of MAPK kinase-3 and -6. In addition, blocking p38 signaling in bone marrow stromal cells partially inhibited IL-1beta and TNF-alpha-induced osteoclastogenesis in vitro. Results from these studies indicate that p38 MAPK is a major signaling pathway involved in IL-1beta and TNF-alpha-induced RANKL expression in bone marrow stromal cells.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, U.S. Gov't, Non-P.H.S.

MeSH terms

  • Animals
  • Bone Marrow Cells / drug effects
  • Bone Marrow Cells / enzymology
  • Bone Marrow Cells / metabolism*
  • Carrier Proteins / biosynthesis*
  • Carrier Proteins / genetics
  • Cell Differentiation
  • Cell Line
  • Cytokines / pharmacology*
  • Genes, Reporter
  • Imidazoles / pharmacology
  • Interleukin-1 / antagonists & inhibitors
  • Interleukin-1 / pharmacology
  • MAP Kinase Kinase 3 / antagonists & inhibitors
  • MAP Kinase Kinase 3 / genetics
  • MAP Kinase Kinase 3 / metabolism
  • MAP Kinase Kinase 6 / antagonists & inhibitors
  • MAP Kinase Kinase 6 / genetics
  • MAP Kinase Kinase 6 / metabolism
  • MAP Kinase Signaling System / drug effects
  • Membrane Glycoproteins / biosynthesis*
  • Membrane Glycoproteins / genetics
  • Mice
  • Mitogen-Activated Protein Kinase Kinases / metabolism*
  • Mutation
  • Osteoclasts / cytology
  • Protein Kinase Inhibitors / pharmacology
  • Pyridines / pharmacology
  • RANK Ligand
  • RNA, Messenger / metabolism
  • Receptor Activator of Nuclear Factor-kappa B
  • Stromal Cells / drug effects
  • Stromal Cells / enzymology
  • Stromal Cells / metabolism
  • Transcriptional Activation
  • Tumor Necrosis Factor-alpha / antagonists & inhibitors
  • Tumor Necrosis Factor-alpha / pharmacology
  • p38 Mitogen-Activated Protein Kinases / antagonists & inhibitors
  • p38 Mitogen-Activated Protein Kinases / metabolism*

Substances

  • Carrier Proteins
  • Cytokines
  • Imidazoles
  • Interleukin-1
  • Membrane Glycoproteins
  • Protein Kinase Inhibitors
  • Pyridines
  • RANK Ligand
  • RNA, Messenger
  • Receptor Activator of Nuclear Factor-kappa B
  • Tnfrsf11a protein, mouse
  • Tnfsf11 protein, mouse
  • Tumor Necrosis Factor-alpha
  • p38 Mitogen-Activated Protein Kinases
  • MAP Kinase Kinase 3
  • MAP Kinase Kinase 6
  • Mitogen-Activated Protein Kinase Kinases
  • SB 203580