Reduced expression of dentin sialophosphoprotein is associated with dysplastic dentin in mice overexpressing transforming growth factor-beta 1 in teeth.

[dentin dysplasia]

Transforming growth factor (TGF )-beta 1 is expressed in developing tooth from the initiation stage through adulthood . Odontoblast-specific expression of TGF-beta 1 in the tooth continues throughout life ; however , the precise biological functions of this growth factor in the odontoblasts are not clearly understood . Herein , we describe the generation of transgenic mice that overexpress active TGF-beta 1 predominantly in the odontoblasts . Teeth of these mice show a significant reduction in the tooth mineralization , defective dentin formation , and a relatively high branching of dentinal tubules . Dentin extracellular matrix components such as type I and III collagens are increased and deposited abnormally in the dental pulp , similar to the hereditary human tooth disorders such as dentin dysplasia and dentinogenesis imperfecta . Calcium , one of the crucial inorganic components of mineralization , is also apparently increased in the transgenic mouse teeth . Most importantly , the expression of dentin sialophosphoprotein (dspp ), a candidate gene implicated in dentinogenesis imperfecta II (MIM 125420 ), is significantly down-regulated in the transgenic teeth . Our results provide in vivo evidence suggesting that TGF-beta 1 mediated expression of dspp is crucial for dentin mineralization . These findings also provide for the first time a direct experimental evidence indicating that decreased dspp gene expression along with the other cellular changes in odontoblasts may result in human hereditary dental disorders like dentinogenesis imperfecta II (MIM 125420 ) and dentin dysplasia (MIM 125400 and 125420 ).

Diseases
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Diseases presenting "crucial inorganic components" symptom

dentin dysplasia

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