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Dentin defects caused by a Dspp−1 frameshift mutation are associated with the activation of autophagy.

Authors :
Liang, Tian
Smith, Charles E.
Hu, Yuanyuan
Zhang, Hong
Zhang, Chuhua
Xu, Qian
Lu, Yongbo
Qi, Ling
Hu, Jan C.-C.
Simmer, James P.
Source :
Scientific Reports; 4/19/2023, Vol. 13 Issue 1, p1-18, 18p
Publication Year :
2023

Abstract

Dentin sialophosphoprotein (DSPP) is primarily expressed by differentiated odontoblasts (dentin-forming cells), and transiently expressed by presecretory ameloblasts (enamel-forming cells). Disease-causing DSPP mutations predominantly fall into two categories: 5' mutations affecting targeting and trafficking, and 3' − 1 frameshift mutations converting the repetitive, hydrophilic, acidic C-terminal domain into a hydrophobic one. We characterized the dental phenotypes and investigated the pathological mechanisms of Dspp<superscript>P19L</superscript> and Dspp<superscript>−1fs</superscript> mice that replicate the two categories of human DSPP mutations. In Dspp<superscript>P19L</superscript> mice, dentin is less mineralized but contains dentinal tubules. Enamel mineral density is reduced. Intracellular accumulation and ER retention of DSPP is observed in odontoblasts and ameloblasts. In Dspp<superscript>−1fs</superscript> mice, a thin layer of reparative dentin lacking dentinal tubules is deposited. Odontoblasts show severe pathosis, including intracellular accumulation and ER retention of DSPP, strong ubiquitin and autophagy activity, ER-phagy, and sporadic apoptosis. Ultrastructurally, odontoblasts show extensive autophagic vacuoles, some of which contain fragmented ER. Enamel formation is comparable to wild type. These findings distinguish molecular mechanisms underlying the dental phenotypes of Dspp<superscript>P19L</superscript> and Dspp<superscript>−1fs</superscript> mice and support the recently revised Shields classification of dentinogenesis imperfecta caused by DSPP mutations in humans. The Dspp<superscript>−1fs</superscript> mice may be valuable for the study of autophagy and ER-phagy. [ABSTRACT FROM AUTHOR]

Details

Language :
English
ISSN :
20452322
Volume :
13
Issue :
1
Database :
Complementary Index
Journal :
Scientific Reports
Publication Type :
Academic Journal
Accession number :
163188914
Full Text :
https://doi.org/10.1038/s41598-023-33362-1