Alteration of the kinetics of type I procollagen synthesis in human osteosarcoma cells by 1,25-dihydroxyvitamin D3

Toshihisa Kojima, Ken Ichi Kozaki, Shinsuke Saga, Yoshio Hashizume, Naoki Ishiguro, Hisashi Iwata, Osamu Miyaishi

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3 Citations (Scopus)

Abstract

The kinetics of type I procollagen synthesis in a human osteosarcoma cell line, MG 63, were investigated after treatment with 1,25- dihydroxyvitamin D3 (1,25-(OH)2 D3), a hormonal inducer of phenotypic differentiation. Pulse label and chase experiments demonstrated greatly enhanced production and more rapid reduction of intracellular procollagen molecules in the 1,25 (OH)2 D3-treated cells as compared to the nontreated case. After a chase for 1 h, labeled procollagen was reduced by nine-tenths in 1,25-(OH)2 D3-treated cells, while half of the radioactivity still remained in nontreated cells. The expression rate of type 1 collagen, which was examined by pulse label experiment, was elevated in association with an increase in the mRNA coding for the type 1 collagen α 1 chain by 1,25- (OH)2 D3 treatment. However, the amount of intracellular procollagen present after 4 h continuous labeling was almost the same, independent of the 1,25-(OH)2 D3 treatment. Thus, we conclude that strage of the molecule was not affected. The results therefore suggest an increase in both the synthesis and secretion of type 1 collagen. The 1,25-(OH)2 D3 treatment was also found to induce the α subunit of prolyl 4-hydroxylase and to be associated with an elevated level of hydroxyproline in the procollagen. Moreover, gelatinase B-resistant procollagen molecules, indicative of intracellular procollagen molecules in the stable triple helical form, were detected only in the 1,25 (OH)2 D3-treated cells. These data suggest more efficient proline hydroxylation is involved in rapid secretion of procollagen after hormone administration. The present evidence points to posttranslational control of procollagen synthesis.

Original languageEnglish
Pages (from-to)542-549
Number of pages8
JournalJournal of Cellular Biochemistry
Volume65
Issue number4
DOIs
Publication statusPublished - Jun 15 1997

Keywords

  • 1,25-dihydroxyvitamin D
  • human osteosarcoma cells
  • procollagen synthesis
  • proline hydroxylation
  • type 1 collagen

ASJC Scopus subject areas

  • Biochemistry
  • Molecular Biology
  • Cell Biology

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