Postnatal β-catenin deletion from Dmp1-expressing osteocytes/osteoblasts reduces structural adaptation to loading, but not periosteal load-induced bone formation

Kyung Shin Kang, Jung Min Hong, Alexander Robling

Research output: Contribution to journalArticle

4 Citations (Scopus)

Abstract

Mechanical signal transduction in bone tissue begins with load-induced activation of several cellular pathways in the osteocyte population. A key pathway that participates in mechanotransduction is Wnt/Lrp5 signaling. A putative downstream mediator of activated Lrp5 is the nucleocytoplasmic shuttling protein β-catenin (βcat), which migrates to the nucleus where it functions as a transcriptional co-activator. We investigated whether osteocytic βcat participates in Wnt/Lrp5-mediated mechanotransduction by conducting ulnar loading experiments in mice with or without chemically induced βcat deletion in osteocytes. Mice harboring βcat floxed loss-of-function alleles (βcatf/f) were bred to the inducible osteocyte Cre transgenic 10 kbDmp1-CreERt2. Adult male mice were induced to recombine the βcat alleles using tamoxifen, and intermittent ulnar loading sessions were applied over the following week. Although adult-onset deletion of βcat from Dmp1-expressing cells reduced skeletal mass, the bone tissue was responsive to mechanical stimulation as indicated by increased relative periosteal bone formation rates in recombined mice. However, load-induced improvements in cross sectional geometric properties were compromised in recombined mice. The collective results indicate that the osteoanabolic response to loading can occur on the periosteal surface when β-cat levels are significantly reduced in Dmp1-expressing cells, suggesting that either (i) only low levels of β-cat are required for mechanically induced bone formation on the periosteal surface, or (ii) other additional downstream mediators of Lrp5 might participate in transducing load-induced Wnt signaling.

Original languageEnglish (US)
Pages (from-to)138-145
Number of pages8
JournalBone
Volume88
DOIs
StatePublished - Jul 1 2016

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Osteocytes
Catenins
Osteoblasts
Osteogenesis
Cellular Mechanotransduction
Alleles
Bone and Bones
Tamoxifen

Keywords

  • Loading
  • Mechanical strain
  • Osteoporosis
  • Wnt
  • β-Catenin

ASJC Scopus subject areas

  • Physiology
  • Endocrinology, Diabetes and Metabolism
  • Histology

Cite this

Postnatal β-catenin deletion from Dmp1-expressing osteocytes/osteoblasts reduces structural adaptation to loading, but not periosteal load-induced bone formation. / Kang, Kyung Shin; Hong, Jung Min; Robling, Alexander.

In: Bone, Vol. 88, 01.07.2016, p. 138-145.

Research output: Contribution to journalArticle

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