TY - JOUR
T1 - Alteration of the kinetics of type I procollagen synthesis in human osteosarcoma cells by 1,25-dihydroxyvitamin D3
AU - Kojima, Toshihisa
AU - Kozaki, Ken Ichi
AU - Saga, Shinsuke
AU - Hashizume, Yoshio
AU - Ishiguro, Naoki
AU - Iwata, Hisashi
AU - Miyaishi, Osamu
PY - 1997/6/15
Y1 - 1997/6/15
N2 - 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.
AB - 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.
KW - 1,25-dihydroxyvitamin D
KW - human osteosarcoma cells
KW - procollagen synthesis
KW - proline hydroxylation
KW - type 1 collagen
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U2 - 10.1002/(SICI)1097-4644(19970615)65:4<542::AID-JCB9>3.0.CO;2-O
DO - 10.1002/(SICI)1097-4644(19970615)65:4<542::AID-JCB9>3.0.CO;2-O
M3 - Article
C2 - 9178103
AN - SCOPUS:0030910509
VL - 65
SP - 542
EP - 549
JO - Journal of supramolecular structure and cellular biochemistry
JF - Journal of supramolecular structure and cellular biochemistry
SN - 0730-2312
IS - 4
ER -