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Updated: Aug 13, 2026

Stimulation of Notch Signaling in Mouse Osteoclast Precursors
08:01

Stimulation of Notch Signaling in Mouse Osteoclast Precursors

Published on: February 28, 2017

Notch 1 overexpression inhibits osteoblastogenesis by suppressing Wnt/beta-catenin but not bone morphogenetic protein

Valerie Deregowski1, Elisabetta Gazzerro, Leah Priest

  • 1Department of Research, Saint Francis Hospital and Medical Center, Hartford, Connecticut 06105-1299, USA.

The Journal of Biological Chemistry
|January 13, 2006
PubMed

Insights

Notch intracellular domain (NICD) overexpression inhibits osteoblastogenesis by suppressing Wnt signaling, not BMP signaling. HES-1 mediates Notch

Area of Science:

  • Cell Biology
  • Molecular Biology
  • Stem Cell Biology

Background:

  • Notch proteins are key regulators of cell-fate decisions.
  • Constitutive activation of Notch, via its intracellular domain (NICD), is known to impair osteoblastogenesis.
  • The precise molecular mechanisms underlying NICD's inhibitory effects on bone formation remain unclear.

Purpose of the Study:

  • To investigate the molecular mechanisms by which Notch intracellular domain (NICD) overexpression affects osteoblast differentiation.
  • To determine whether NICD interferes with bone morphogenetic protein (BMP)-2 and Wnt 3a signaling pathways.
  • To elucidate the role of HES-1 in mediating Notch's effects on osteoblastogenesis.

Main Methods:

  • Constitutive activation of Notch 1 in ST-2 cells.
  • Assessment of alkaline phosphatase activity (APA) in response to BMP-2 and Wnt 3a.
  • Analysis of Smad and mitogen-activated protein kinase (MAPK) phosphorylation.
  • Evaluation of Wnt/beta-catenin signaling, including beta-catenin levels and Wnt-dependent gene expression.
  • RNA interference targeting HES-1 and Groucho1/TLE1.

Main Results:

  • NICD overexpression opposed the effects of BMP-2 and Wnt 3a on alkaline phosphatase activity.
  • NICD suppressed Wnt 3a-induced beta-catenin stabilization and Wnt-dependent gene expression, but did not affect BMP-2-induced Smad phosphorylation.
  • HES-1 (Hes Family BHLH Transcription Factor 1) silencing partially rescued Wnt 3a effects on APA and reversed NICD's inhibitory impact on Wnt signaling.

Conclusions:

  • NICD overexpression inhibits osteoblastogenesis primarily by suppressing Wnt signaling, while sparing BMP signaling.
  • HES-1 plays a crucial role in mediating the inhibitory effects of Notch on osteoblast differentiation.
  • Targeting HES-1 may offer a therapeutic strategy to counteract Notch-mediated suppression of bone formation.

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