Targeted disruption of cadherin-11 leads to a reduction in bone density in calvaria and long bone metaphyses

The migration and adhesion of osteoblasts requires several classical cadherins, Cadherin-11, one of the classical cadherins, was expressed in mouse osteoblasts in skull bone and femur, revealed by immunohistochemistry. To elucidate the function of cadherin-ll in osteoblastogenesis, cadherin-ll null mutant mice were investigated, Although apparently normal at birth, Alizarin red staining of null mutant mice showed a reduced calcified area at the frontal suture that caused a round-shaped calvaria with increasing animal age to 3 months. Consequently, there was a reduction in bone density at the femoral metaphyses and the diploe of calvaria in null mutant mice. In the in vitro culture of newborn calvarial cells, the calcified area-of mutant cells was smaller than those derived from wild-type littermates. These results show that absence of cadherin-ll leads to reduced bone density in some parts of skeletons including calvaria and long bone metaphyses, and thus suggest that cadherin-ll plays roles in the regulation of osteoblast differentiation and in the mineralization of the osteoid matrix.