Role of the small integrin-binding ligand N-linked glycoprotein (SIBLING), bone sialoprotein (BSP) in bone development and remodeling.

L. Malaval (1) , J. Aubin (2) , L. Vico (1)

1 Contraintes mécaniques et tissu osseux
2 Department of Molecular and Medical Genetics

Members of the “small, integrin binding ligand, N-linked glycoprotein” (SIBLING) family, which have both mineral binding and cell binding (integrins) abilities, appear as potent regulators of bone mineralisation and remodeling. Among these, osteopontin (OPN) and bone sialoprotein (BSP) are highly expressed in early bone. Gene knockout of OPN results in increased mineralisation and a resorption defect making mutant mice unable to respond to such challenges as hindlimb unloading. We recently published the phenotype of mice with a knockout of BSP (BSP-/-). We showed that BSP-/- mice are smaller than the wild type counterpart, with a lower bone-formation rate but a higher trabecular volume at 4 month, due to impaired resorption. Lack of BSP results in slower bone repair in a cortical defect model, but does not prevent bone loss due to unloading, in contrast to OPN knockout. These results highlight the specificity of BSP roles in the bone context, as well as the nonredundancy of function of SIBLING family members in skeletal biology.

Keywords: bone; bone remodeling; osteoblast; osteoclast; extracellular matrix; SIBLING; bone sialoprotein

Domains: Life Sciences [q-bio]; Cellular Biology

L. Malaval, J. Aubin, L. Vico. Role of the small integrin-binding ligand N-linked glycoprotein (SIBLING), bone sialoprotein (BSP) in bone development and remodeling.. Osteoporosis International, 2009, epub ahead of print. ⟨10.1007/s00198-009-0869-2⟩. ⟨ujm-00374655⟩