Differences in Composition of Cell-attachment Sialoproteins between Dentin and Bone

Abstract

Matrices of dentin and bone were compared with respect to the content of cell-attachment sialoproteins. The levels of two sialoproteins, osteopontin (OPN) and bone sialoprotein (BSP), were determined in dentin and bone by immunochemical procedures. Polyclonal antibodies against bovine BSP and an antibody against the amino-terminal decapeptide of rat OPN were used. The relative levels of OPN and BSP in dentin were less than one-tenth of the levels in bone. The differences between dentin and bone levels of OPN and BSP were thus larger than those for osteonectin or bone Gla protein in the two tissues. The scarcity of the cell-attachment proteins in dentin may reflect the metabolic inactivity of dentin.

Osteopontin at mineralized tissue interfaces in bone, teeth, and osseointegrated implants: Ultrastructural distribution and implications for mineralized tissue formation, turnover, and repair

“…In the tooth, OPN is a major component of cementum and a relatively minor component of dentin (Fujisawa et al, 1993;Helder et al, 1993;McKee et al, submitted). Although a quantitative, immunogold study comparing the OPN content between the tissues of bone and teeth has not yet been performed, comparative qualitative estimates of labeling patterns from the same tissue section of the mandible, which simultaneously contains alveolar bone, dentin, and cementum, indicate that OPN is substantially more concentrated in acellular extrinsic fiber cementum than in other mineralized tissues McKee et al, submitted).…”

Identification and Characterization of the Carboxyl-terminal Region of Rat Dentin Sialoprotein

“…These cells secrete a unique set of gene products similar to those expressed by osteoblasts in the formation of bone. The noncollagenous proteins include osteonectin, osteocalcin, osteopontin (OPN), 1 bone sialoprotein, and dentin matrix protein 1 (Dmp-1), found in bone and dentin, and dentin phosphoprotein (DPP) and dentin sialoprotein (DSP), occurring in dentin but not in bone (1)(2)(3)(4)(5). Because these noncollagenous proteins are very acidic and are secreted into the extracellular matrix during the formation and mineralization of these tissues, it is generally accepted that they play key biological roles in the formation of dentin and bone (6); however, details concerning their precise functions are unknown.…”

Serum bone sialoprotein as a marker of tumour burden and neoplastic bone involvement and as a prognostic factor in multiple myeloma

“…BSP is a phosphorylated 70-80 kDa glycoprotein that accounts for 5-10% of the non-collagenous bone matrix (Fisher et al, 1983;Heinegard and Oldberg, 1989). The protein is a major synthetic product of active osteo-and odontoblasts and contains an ArgGly-Asp (RGD) sequence (Chen et al, 1991;Fujisawa et al, 1993;Shapiro et al, 1993). This sequence is recognized by various integrin receptors including the αrβ 3 vitronectin receptor (CD51/CD61) (Oldberg et al, 1988;Ross et al, 1993), which is expressed by osteoclasts (Ross et al, 1993).…”