Synthesis and intracellular transportation of type I procollagen during functional differentiation of odontoblasts

Histochem Cell Biol. 2009 May;131(5):583-91. doi: 10.1007/s00418-009-0556-6. Epub 2009 Jan 21.

Abstract

The expression of type I collagen, the most component of dentin extracellular matrix proteins (ECMs) in odontoblast is correlated with the activity of dentin formation. Since odontoblast possesses a distinct cellular process for protein transport into the dentinal tubule, it is important to examine the intracellular protein localization. However, a study focusing on odontoblast processes has not been performed. Type I collagen is synthesized as procollagen, which is immediately converted to collagen upon secretion. After characterization of antiserum to rat type I procollagen, we investigated the intracellular localization of type I procollagen in odontoblasts during and after dentinogenesis, using immunohistochemistry and in situ hybridization. The level of mRNA expression decreased during dentinogenesis, whereas the intracellular localization of type I procollagen in odontoblast processes become more distinct. The percentage of dentinal tubules with type I procollagen increased significantly with aging. Odontoblasts in pulp horn, in particular, showed moderate expression of type I procollagen after dentinogenesis. Since loss of occlusion also caused a significant decrease in type I procollagen, we concluded that occlusal stimulation activated type I procollagen synthesis in odontoblasts. We also suggest that analysis of intracellular transport of type I procollagen via odontoblast processes may be a new approach to evaluation of odontoblast function.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Collagen Type I / metabolism*
  • Dentin / cytology
  • Dentin / metabolism*
  • Dentinogenesis*
  • Odontoblasts / cytology
  • Odontoblasts / metabolism*
  • Osteopontin / metabolism*
  • Protein Transport
  • Rats
  • Rats, Wistar

Substances

  • Collagen Type I
  • Spp1 protein, rat
  • Osteopontin