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Possible involvement of protein kinases and Smad2 signaling pathways on osteoclast differentiation enhanced by

Y Murase1, N Okahashi, T Koseki

  • 1Department of Periodontology, Aichi Gakuin University, Nagoya, Japan.

Journal of Cellular Physiology
|June 26, 2001
PubMed

Insights

Osteoblasts produce activin A and follistatin, which regulate bone remodeling. Activin A promotes osteoclast formation via MAP kinase and Smad2 pathways, while follistatin inhibits it, suggesting a role in bone health.

Area of Science:

  • Bone biology
  • Cell signaling
  • Endocrinology

Background:

  • Bone tissues contain activin A and follistatin.
  • Osteoclast differentiation is crucial for bone remodeling.

Purpose of the Study:

  • To investigate the roles of activin A and follistatin in osteoclast differentiation.
  • To elucidate the signaling pathways involved in activin A-mediated osteoclastogenesis.

Main Methods:

  • Cocultures of mouse bone marrow cells and osteoblasts.
  • Stimulation with 1alpha,25 dihydroxyvitamin D(3), prostaglandin E(2), and interleukin-1alpha.
  • RT-PCR, Western blot analysis, and antibody neutralization.

Main Results:

  • Follistatin and anti-activin A antibody inhibited osteoclast formation.
  • Activin A synergistically stimulated osteoclast differentiation via RANKL.
  • Activin A induced phosphorylation of ERK1/2, p38 MAP kinase, and Smad2 in bone marrow macrophages.

Conclusions:

  • Osteoblast-derived activin A and follistatin play significant roles in osteoclast differentiation.
  • MAP kinase and Smad2 signaling pathways are involved in activin A-enhanced osteoclastogenesis.
  • These findings contribute to understanding bone remodeling regulation.

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