title: Dentin sialophosphoprotein: a regulatory protein for dental pulp stem cell identity and fate.
abstract: The dentin sialophosphoprotein (dspp) transcript is expressed during tooth development as a DSPP precursor protein, which then undergoes cleavage to form mature dentin sialoprotein (DSP) and phosphophoryn (PP) proteins. Previous studies using DSPP-knockout (KO) mice have reported that these animals have hypomineralized teeth, thin dentin, and a large dental pulp chamber, similar to those from patients with dentinogenesis imperfecta III. However, there is no information about factors that regulate dental pulp stem cell lineage fate, a critical early event in the odontoblast-dentin mineralization scheme. To reveal the role of DSPP in odontoblast lineage differentiation during tooth development, we systematically examined teeth from wild-type (wt) and DSPP-KO C57BL/6 mice between the ages of postnatal day 1 and 3 months. We found developmental abnormalities not previously reported, such as circular dentin formation within dental pulp cells and altered odontoblast differentiation in DSPP-KO mice, even as early as 1 day after birth. Surprisingly, we also identified chondrocyte-like cells in the dental pulp from KO-mice teeth. Thus, these studies that compare wt and DSPP-KO mice suggest that the expression of DSPP precursor protein is required for normal odontoblast lineage differentiation and that the absence of DSPP allows dental pulp cells to differentiate into chondrocyte-like cells, which could negatively impact pulpal wound healing and tissue regeneration.
authors.affiliation: 1 Department of Cariology, Restorative Sciences and Endodontics, School of Dentistry, University of Michigan , Ann Arbor, Michigan.
authors.forename: Shiliang
authors.initials: S
authors.lastname: Guo
authors.forename: Dandrich
authors.initials: D
authors.lastname: Lim
authors.forename: Zhihong
authors.initials: Z
authors.lastname: Dong
authors.forename: Thomas L
authors.initials: TL
authors.lastname: Saunders
authors.forename: Peter X
authors.initials: PX
authors.lastname: Ma
authors.forename: Cynthia L
authors.initials: CL
authors.lastname: Marcelo
authors.forename: Helena H
authors.initials: HH
authors.lastname: Ritchie
mesh_terms: D000818:Animals; D002454:Cell Differentiation / Q000502:physiology*; D003782:Dental Pulp / Q000166:cytology / Q000378:metabolism*; D003804:Dentin / Q000166:cytology / Q000378:metabolism*; D016326:Extracellular Matrix Proteins / Q000235:genetics / Q000378:metabolism*; D051379:Mice; D018345:Mice, Knockout; D009804:Odontoblasts / Q000166:cytology / Q000378:metabolism*; D010750:Phosphoproteins / Q000235:genetics / Q000378:metabolism*; D012795:Sialoglycoproteins / Q000235:genetics / Q000378:metabolism*; D013234:Stem Cells / Q000166:cytology / Q000378:metabolism*; D000099311:Dentin Sialophosphoprotein
chemical_list: D016326:Extracellular Matrix Proteins; D010750:Phosphoproteins; D012795:Sialoglycoproteins; D000099311:Dentin Sialophosphoprotein