TY - JOUR
T1 - DSPP Is Essential for Normal Development of the Dental-Craniofacial Complex
AU - Chen, Y.
AU - Zhang, Y.
AU - Ramachandran, A.
AU - George, A.
N1 - Publisher Copyright:
© International & American Associations for Dental Research 2016.
PY - 2016/3/1
Y1 - 2016/3/1
N2 - The craniofacial skeleton is derived from both neural crest cells and mesodermal cells; however, the majority of the bone, cartilage, and connective tissue is derived from the neural crest. Dentin sialophosphoprotein (DSPP) is a precursor protein that is expressed by the connective tissues of the craniofacial skeleton, namely, bone and dentin with high expression levels in the dentin matrix. Gene ablation studies have shown severe dental defects in DSPP-null mutant mice. Therefore, to elucidate the role of DSPP on the developing dental-craniofacial complex, we evaluated phenotypic changes in the structure of intramembranous bone and dentin mineralization using 3 different age groups of DSPP-null and wild-type mice. Results from micro-computed tomographic, radiographic, and optical microscopic analyses showed defective dentin, alveolar and calvarial bones, and sutures during development. The impaired mineralization of the cranial bone correlated well with low expression levels of Runx2, Col1, and OPN identified using calvarial cells from DSPP-null and wild-type mice in an in vitro culture system. However, the upregulation of MMP9, MMP2, FN, and BSP was observed. Interestingly, the null mice also displayed low serum phosphate levels, while calcium levels remained unchanged. Alizarin red and von Kossa staining confirmed the dysfunction in the terminal differentiation of osteoblasts obtained from the developing calvaria of DSPP-null mice. Immunohistochemical analysis of the developing molars showed changes in Runx2, Gli1, Numb, and Notch expression in the dental pulp cells and odontoblasts of DSPP-null mice when compared with wild-type mice. Overall, these observations provide insight into the role of DSPP in the normal development of the calvaria, alveolar bone, and dentin-pulp complex.
AB - The craniofacial skeleton is derived from both neural crest cells and mesodermal cells; however, the majority of the bone, cartilage, and connective tissue is derived from the neural crest. Dentin sialophosphoprotein (DSPP) is a precursor protein that is expressed by the connective tissues of the craniofacial skeleton, namely, bone and dentin with high expression levels in the dentin matrix. Gene ablation studies have shown severe dental defects in DSPP-null mutant mice. Therefore, to elucidate the role of DSPP on the developing dental-craniofacial complex, we evaluated phenotypic changes in the structure of intramembranous bone and dentin mineralization using 3 different age groups of DSPP-null and wild-type mice. Results from micro-computed tomographic, radiographic, and optical microscopic analyses showed defective dentin, alveolar and calvarial bones, and sutures during development. The impaired mineralization of the cranial bone correlated well with low expression levels of Runx2, Col1, and OPN identified using calvarial cells from DSPP-null and wild-type mice in an in vitro culture system. However, the upregulation of MMP9, MMP2, FN, and BSP was observed. Interestingly, the null mice also displayed low serum phosphate levels, while calcium levels remained unchanged. Alizarin red and von Kossa staining confirmed the dysfunction in the terminal differentiation of osteoblasts obtained from the developing calvaria of DSPP-null mice. Immunohistochemical analysis of the developing molars showed changes in Runx2, Gli1, Numb, and Notch expression in the dental pulp cells and odontoblasts of DSPP-null mice when compared with wild-type mice. Overall, these observations provide insight into the role of DSPP in the normal development of the calvaria, alveolar bone, and dentin-pulp complex.
KW - calvaria
KW - dental pulp
KW - dentin sialophosphoprotein
KW - mandible
KW - mineralization
KW - odontoblasts
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U2 - 10.1177/0022034515610768
DO - 10.1177/0022034515610768
M3 - Article
C2 - 26503913
AN - SCOPUS:84975784271
SN - 0022-0345
VL - 95
SP - 302
EP - 310
JO - Journal of Dental Research
JF - Journal of Dental Research
IS - 3
ER -