First published online October 24, 2008
Development 135, 2203e (2008)
© The Company of Biologists Limited
Boning up on BMP-Wnt interactions
Bone morphogenetic proteins (BMPs) were discovered because they induce
ectopic bone formation but now, on
p. 3801, Kamiya and
colleagues unexpectedly report that BMP signalling negatively regulates bone
mass during embryogenesis by upregulating the formation of bone-reabsorbing
cells (osteoclasts). To investigate the role of BMP signalling during
endogenous bone formation, the researchers disrupted the expression of the BMP
receptor BMPR1A in osteoblasts (bone-forming cells) in mouse embryos. They
show that levels of bone-resorption markers are reduced in these embryos
(which indicates inhibition of osteoclastogenesis) and that bone mass is
increased. Wnt signalling (which inhibits the RANKL-OPG pathway, an important
mediator of osteoclastogenesis) is upregulated in the
Bmpr1a-deficient osteoblasts, they report. Other experiments indicate
that BMPR1A deficiency upregulates Wnt signalling by downregulating
sclerostin, a Wnt inhibitor and bone mass mediator. Thus, the researchers
suggest, BMP signalling in osteoblasts restrains endogenous bone mass
indirectly by downregulating canonical Wnt signalling through sclerostin and,
possibly, by directly upregulating the RANKL-OPG pathway.

CiteULike
Complore
Connotea
Del.icio.us
Digg
Reddit
Technorati
Twitter What's this?
Related articles in Development:
- BMP signaling negatively regulates bone mass through sclerostin by inhibiting the canonical Wnt pathway
- Nobuhiro Kamiya, Ling Ye, Tatsuya Kobayashi, Yoshiyuki Mochida, Mitsuo Yamauchi, Henry M. Kronenberg, Jian Q. Feng, and Yuji Mishina
Development 2008 135: 3801-3811.
[Abstract]
[Full Text]