The transition of cadherin expression in osteoblast differentiation from mesenchymal cells: consistent expression of cadherin-11 in osteoblast lineage.

Osteoblasts are derived originally from pluripotent mesenchymal stem cells on migration into the bone matrix. To elucidate the contribution of classical cadherins in this differentiation pathway, we developed a new protocol for their analysis and studied their specific expressions in various cell lines of the mesenchymal lineage, including osteoblasts. N-cadherin was expressed constitutively in all cell lines examined except an osteocyte-like cell line whereas cadherin-11 was expressed selectively in preosteoblast and preadipocyte cell lines. P-cadherin also was expressed in primary cultures of calvarial cells and mature osteoblasts at a relatively low level compared with N-cadherin and cadherin-11. M-cadherin was expressed only in a premyoblast cell line. We observed the transition of cadherin expression from M-cadherin to cadherin-11 in the premyoblast cell line when osteogenic differentiation was induced by treatment with bone morphogenetic protein 2 (BMP-2), while the expression of N-cadherin remained unchanged. In contrast, when a preadipocyte cell line, which shows a similar pattern of cadherin expression to osteoblasts, was induced to undergo adipogenic differentiation, the expression of N-cadherin and cadherin-11 was decreased. These observations characterize the cadherin expression profile of mesenchymal lineage cells, especially osteoblasts, which regularly express cadherin-11. Cadherin-11 may affect cell sorting, alignment, and separation through differentiation.