Sequential Expression of Bone Matrix Proteins During Rat Calvaria Osteoblast Differentiation and Bone Nodule Formation In Vitro
Open Access
- 1 April 1997
- journal article
- Published by SAGE Publications in Journal of Histochemistry & Cytochemistry
- Vol. 45 (4), 493-503
- https://doi.org/10.1177/002215549704500402
Abstract
We investigated the expression of osteocalcin (OC), bone sialoprotein (BSP), osteonectin (ON), and alkaline phosphatase (ALP) during cell differentiation and bone nodule formation by fetal rat calvaria cells, using immunofluorescent and immunogold techniques at light and electron microscopic levels. Six hours after plating all proteins were expressed in calvaria cells. However, expression was not detected during the proliferation phase after plating. Cell morphological modifications were observed in osteoblastic cells expressing ALP, OC, and BSP, but not ON. During the matrix formation phase, all proteins were expressed with various intensities and OC was limited to differentiated osteoblastic cells. EM observations demonstrated that BSP was selectively associated with clusters of needle-like crystals, but not with collagen fibers, in mineralization foci and in the mineralized matrix. OC was localized intracellularly and in all the extracellular compartments, and was concentrated at the mineralization front. ON was distributed uniformly throughout the osteoid and mineralized matrix, which was intensely labeled. The results show that the expression of bone matrix proteins during differentiation of calvaria cells and nodule formation in vitro duplicate what is observed during osteogenesis in vivo.Keywords
This publication has 60 references indexed in Scilit:
- Ultrastructural immunolocalization of noncollagenous (osteopontin and osteocalcin) and plasma (albumin and α2HS-glycoprotein) proteins in rat boneJournal of Bone and Mineral Research, 1993
- In vitro differentiation and mineralization of cartilaginous nodules from enzymatically released rat nasal cartilage cellsBiology of the Cell, 1993
- High‐resolution immunolocalization of osteopontin and osteocalcin in bone and cartilage during endochondral ossification in the chicken tibiaThe Anatomical Record, 1992
- Temporal studies on the tissue compartmentalization of bone sialoprotein (BSP), osteopontin (OPN), and SPARC protein during bone formation In VitroJournal of Cellular Physiology, 1992
- Direct flow cytometric quantification of alkaline phosphatase activity in rat bone marrow stromal cells.Journal of Histochemistry & Cytochemistry, 1992
- Immunohistochemical localization of bone sialoprotein in foetal porcine bone tissues: comparisons with secreted phosphoprotein 1 (SPP-1, osteopontin) and SPARC (osteonectin)Journal of Molecular Histology, 1991
- Characterization of endosteal osteoblastic cells isolated from mouse caudal vertebraeBone, 1988
- Ultrastructural analysis of bone nodules formed in vitro by isolated fetal rat calvaria cellsBone, 1988
- Expression of differentiated function by mineralizing cultures of chicken osteoblastsDevelopmental Biology, 1987
- Characterization of a bone-specific alkaline phosphatase in chick limb mesenchymal cell culturesDevelopmental Biology, 1981