Tributyltin Alters Osteocalcin, Matrix Metalloproteinase 20 and Dentin Sialophosphoprotein Gene Expression in Mineralizing Mouse Embryonic Tooth in vitro

Abstract

We showed in a previous in vitro study that tributyltin (TBT) arrests dentin mineralization and enamel formation in developing mouse tooth. The present aim was to investigate the effect of TBT on the expression of genes associated with mineralization of dental hard tissues. Embryonic day 18 mouse mandibular first molars were cultured for 3, 5 or 7 days and exposed to 1.0 µM TBT and studied by real-time quantitative polymerase chain reaction (RT-QPCR) for the expressions of osteocalcin (Ocn), alkaline phosphatase (Alpl), dentin matrix protein 1 (Dmp1), dentin sialophosphoprotein (Dspp) and matrix metalloproteinase 20 (Mmp-20).Ocn, Mmp-20 and Dspp, whose expressions showed changes in RT- QPCR, were further analyzed by in situ hybridization of tissue sections. In situ hybridization showed that TBT decreased Ocn expression in odontoblasts but increased the expression in the epithelial tooth compartment. In QPCR assays, the net effect in the whole tooth was increased expression. TBT also reduced Mmp-20 expression in ameloblasts and odontoblasts. Dspp expression varied but both QPCR assays and in situ hybridization showed a decreasing trend. TBT exposure had no clear effect on Alpl and Dmp1 expressions. Increased Ocn expression by epithelial enamel organ may inhibit dentin mineralization and enamel formation. Decreased Ocn, Mmp-20 and Dspp expressions in odontoblasts may indicate delayed cell differentiation, or TBT may specifically decrease the expression of genes involved in dentin mineralization. While decreased Mmp-20 expression by TBT in ameloblasts may impair enamel mineralization, the coincident reduction in Mmp-20 and Dspp expressions in odontoblasts may potentiate the delay of dentin mineralization.

Differentiation of Human Skeletal Muscle Stem Cells into Odontoblasts Is Dependent on Induction of α1 Integrin Expression

“…Exposure of RA-treated cell aggregates to BMP-4 triggered their odontoblastic differentiation as measured by a coordinate increase in the expression of a specific set of mineralization-regulating genes. Several non-collagenous proteins important in mineralization are expressed in both bone and dentin but at different levels (32)(33)(34). The ECM protein DSPP is thought to be more tooth-specific and is strongly expressed by odontoblasts (32,35).…”

“…Because both bone and teeth express these markers at variable levels depending on their stage of differentiation, this group of protein indicators has limited use in discriminating between osteoblast and odontoblast lineages. However, MMP-20 (enamelysin) is thought to be highly tooth-specific, and its expression has been found in epithelial ameloblasts and mesenchymal odontoblasts (34,35). Analysis revealed that both cultured ameloblastic and odontoblastic cells, but not osteoblastic cells, expressed high levels of MMP-20 protein (39).…”

BMI and BMD: The Potential Interplay between Obesity and Bone Fragility

“…Bone is an endocrine target tissue highly sensitive to numerous ED [ 189 ]. Data from in vitro and in vivo studies indicate that tributyltin chloride (TBT) can disrupt the process of bone deposition and remodeling [ 190 , 191 , 192 ]. Similarly, TBT seems to stimulate adipogenesis and ectopic adipocyte formation through PPAR-γ activation [ 193 , 194 ].…”

Phenotypes of CCAAT/enhancer‐binding protein beta deficiency: hyperdontia and elongated coronoid process

“…Dentinogenesis imperfecta, a hereditary tooth defect, has been observed in humans with a mutant DSPP gene (Kim et al , 2005) and in p20CEBPB transgenic mice (Savage et al , 2006). Of further note, earlier studies have suggested an influence of IGF1 on dental maturation (Campbell et al , 2009), a preventing effect of RUNX2 upon development of succedaneous tooth organs (D’Souza et al , 1999), and an odontogenic relevance of BGLAP (Salmela et al , 2012). As mentioned earlier, activity of IGF1, RUNX2 and BGLAP was subject to CEBPB regulation (McCarthy et al , 2000; Gutierrez et al , 2002; Wiper‐Bergeron et al , 2007).…”