Cbfa1-independent decrease in osteoblast proliferation, osteopenia, and persistent embryonic eye vascularization in mice deficient in Lrp5, a Wnt coreceptor

M Kato, MS Patel, R Levasseur, I Lobov… - The Journal of cell …, 2002 - rupress.org
M Kato, MS Patel, R Levasseur, I Lobov, BHJ Chang, DA Glass, C Hartmann, L Li…
The Journal of cell biology, 2002rupress.org
The low-density lipoprotein receptor–related protein (Lrp)-5 functions as a Wnt coreceptor.
Here we show that mice with a targeted disruption of Lrp5 develop a low bone mass
phenotype. In vivo and in vitro analyses indicate that this phenotype becomes evident
postnatally, and demonstrate that it is secondary to decreased osteoblast proliferation and
function in a Cbfa1-independent manner. Lrp5 is expressed in osteoblasts and is required
for optimal Wnt signaling in osteoblasts. In addition, Lrp5-deficient mice display persistent …
The low-density lipoprotein receptor–related protein (Lrp)-5 functions as a Wnt coreceptor. Here we show that mice with a targeted disruption of Lrp5 develop a low bone mass phenotype. In vivo and in vitro analyses indicate that this phenotype becomes evident postnatally, and demonstrate that it is secondary to decreased osteoblast proliferation and function in a Cbfa1-independent manner. Lrp5 is expressed in osteoblasts and is required for optimal Wnt signaling in osteoblasts. In addition, Lrp5-deficient mice display persistent embryonic eye vascularization due to a failure of macrophage-induced endothelial cell apoptosis. These results implicate Wnt proteins in the postnatal control of vascular regression and bone formation, two functions affected in many diseases. Moreover, these features recapitulate human osteoporosis-pseudoglioma syndrome, caused by LRP5 inactivation.
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