Related Experiment Video

Updated: Jun 26, 2026

Stimulation of Notch Signaling in Mouse Osteoclast Precursors
08:01

Stimulation of Notch Signaling in Mouse Osteoclast Precursors

Published on: February 28, 2017

Bone morphogenetic protein-2 enhances Wnt/beta-catenin signaling-induced osteoprotegerin expression

Mari M Sato1, Aiko Nakashima, Masayuki Nashimoto

  • 1Department of Biochemistry and Molecular Biology, Hokkaido University, Sapporo, Japan.

Genes to Cells : Devoted to Molecular & Cellular Mechanisms
|January 28, 2009
PubMed

Insights

Wnt/beta-catenin signaling promotes osteoprotegerin (OPG) expression in bone cells. Bone morphogenetic protein-2 (BMP-2) enhances this effect, revealing dual pathways regulating OPG via its promoter.

Area of Science:

  • Cell Biology
  • Molecular Biology
  • Skeletal Biology

Background:

  • Wnt/beta-catenin signaling is crucial for skeletal development.
  • Previous work showed Wnt/beta-catenin inhibits BMP-2-induced myotube suppression via Id1.
  • The role of Wnt/beta-catenin and BMP-2 in OPG and RANKL regulation was unexplored.

Purpose of the Study:

  • To investigate how Wnt/beta-catenin and BMP-2 signaling pathways regulate osteoprotegerin (OPG) and receptor activator of NFkappaB ligand (RANKL) expression.
  • To elucidate the molecular mechanisms underlying OPG gene transcription by these signaling pathways.

Main Methods:

  • Utilized C2C12 and MC3T3-E1 cell lines.
  • Employed gene silencing (shRNA) for glycogen synthase kinase-3beta.
  • Performed transfection assays with OPG gene reporter constructs, including deletion and mutation analyses.
  • Investigated protein-protein interactions using co-immunoprecipitation or similar techniques.

Main Results:

  • Wnt/beta-catenin signaling significantly induced OPG expression in both cell types.
  • Silencing glycogen synthase kinase-3beta also upregulated OPG expression.
  • Wnt/beta-catenin signaling suppressed RANKL expression.
  • Reporter gene assays identified a 1.5 kb OPG promoter fragment regulated by Wnt/beta-catenin via specific responsive sites.
  • BMP-2 potentiated Wnt/beta-catenin-mediated OPG promoter activation.
  • Smad 1 and Smad 4 proteins were found to interact with Wnt/beta-catenin responsive elements on the OPG promoter upon BMP-2 stimulation.

Conclusions:

  • Wnt/beta-catenin signaling directly induces osteoprotegerin (OPG) gene transcription through specific promoter elements.
  • BMP-2 signaling cooperates with Wnt/beta-catenin to enhance OPG expression, involving Smad proteins.
  • These findings reveal a coordinated regulation of OPG by distinct intracellular signaling pathways impacting skeletal homeostasis.

More Related Videos

Covalent Binding of BMP-2 on Surfaces Using a Self-assembled Monolayer Approach10:23

Covalent Binding of BMP-2 on Surfaces Using a Self-assembled Monolayer Approach

Published on: August 26, 2013

Calcification of Vascular Smooth Muscle Cells and Imaging of Aortic Calcification and Inflammation08:43

Calcification of Vascular Smooth Muscle Cells and Imaging of Aortic Calcification and Inflammation

Published on: May 31, 2016

Related Concept Videos

Canonical Wnt Signaling Pathway02:54

Canonical Wnt Signaling Pathway

The gene encoding the main signaling molecules of the Wnt signaling pathways (the Wnt proteins) was discovered almost four decades ago by Nüsslein-Volhard and Wieschaus. They identified and originally named the gene "wingless" (wg) after a phenotype discovered during their landmark genetic screen in Drosophila for body pattern defects. At around the same time, another researcher named Harold Varmus found that a murine tumor virus activates the mammalian wg homolog, Int-1, which results in tumor...
Canonical Wnt Signaling Pathway02:54

Canonical Wnt Signaling Pathway

The gene encoding the main signaling molecules of the Wnt signaling pathways (the Wnt proteins) was discovered almost four decades ago by Nüsslein-Volhard and Wieschaus. They identified and originally named the gene "wingless" (wg) after a phenotype discovered during their landmark genetic screen in Drosophila for body pattern defects. At around the same time, another researcher named Harold Varmus found that a murine tumor virus activates the mammalian wg homolog, Int-1, which results in tumor...
Non-Canonical Wnt Signaling Pathways01:41

Non-Canonical Wnt Signaling Pathways

Wnt is a zygotic effect gene that is expressed during very early embryonic development. It regulates various processes in animals starting from early development through the adult stage, such as organogenesis in the embryo and maintenance of neuronal and blood stem cells. Wnt proteins can induce a wide variety of intracellular pathways depending upon the specific abilities of different Wnt ligands to form a complex with shared and cognate receptors in the presence of different co-receptors. The...
Non-Canonical Wnt Signaling Pathways01:41

Non-Canonical Wnt Signaling Pathways

Wnt is a zygotic effect gene that is expressed during very early embryonic development. It regulates various processes in animals starting from early development through the adult stage, such as organogenesis in the embryo and maintenance of neuronal and blood stem cells. Wnt proteins can induce a wide variety of intracellular pathways depending upon the specific abilities of different Wnt ligands to form a complex with shared and cognate receptors in the presence of different co-receptors. The...
Catenins01:23

Catenins

Catenins are characterized by multiple binding domains and dynamic structures that allow them to function as linker proteins in cell junction complexes. All catenins, except α-catenin, contain a characteristic protein sequence called the armadillo repeat and are therefore also called armadillo proteins.
Catenins in Cell Junctions
Catenins bind to cell adhesion molecules such as cadherins and link them to different cytoskeletal proteins depending on the type of cell junction. At the adherens...
TGF - β Signaling Pathway01:16

TGF - β Signaling Pathway

The TGF-β signaling pathway regulates cell growth, differentiation, adhesion, motility, and development. TGF-β ligands that induce TGF-β signaling are synthesized in their latent form. Several proteases or cell surface receptors such as integrins act upon the latent form, releasing the active ligand. There are three types of mammalian TGF-βs: (TGF-β1, TGF-β2, and TGF-β3) that bind as homodimers or heterodimers to TGF-β receptors. The TGF-β receptors are of three kinds RI, RII, and RIII. The RI...