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

• Published in: Histochemistry and cell biology Vol. 131; no. 5; pp. 583 - 591
• Main Authors: Sato, Shigehisa, Tsuchiya, Masahiro, Komaki, Ken-ichiro, Kusunoki, Shin-ichiro, Tsuchiya, Shinobu, Haruyama, Naoto, Takahashi, Ichiro, Sasano, Yasuyuki, Watanabe, Makoto
• Format: Journal Article
• Language: English
• Published: Berlin/Heidelberg Berlin/Heidelberg : Springer-Verlag 01.05.2009; Springer-Verlag; Springer Nature B.V
• Subjects: Aging; Animals; Biochemistry; Biomedical and Life Sciences; Biomedicine; Cell Biology; Cellular biology; Collagen Type I - metabolism; Dentin - cytology; Dentin - metabolism; Dentinogenesis; Developmental Biology; Odontoblasts - cytology; Odontoblasts - metabolism; Original Paper; Osteopontin - metabolism; Protein Transport; Proteins; Rats; Rats, Wistar; Ribonucleic acid; RNA; Rodents; Occlusion; Odontoblast process; Odontoblast; Differentiation; Type I procollagen
• ISSN: 0948-6143; 1432-119X
• DOI: 10.1007/s00418-009-0556-6

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.