Hormonal regulation of connexin 43 expression and gap junctional communication in human osteoblastic cells.
We have recently shown that connexin 43 (Cx43), a major gap junction protein in osteoblasts, is expressed with an increase in cell density (CHIBA, H. et al. (1993). Cell Struc. Funct., 18: 419-426). In the present study, we examined what kinds of hormones and cytokines regulate the gap junction protein in osteoblastic cells, using a human osteoblastic cell line (SV-HFO) after reaching a confluent density to avoid influence of cell proliferation. Either retinoic acid (RA) or transforming growth factor-beta 1 (TGF-beta 1) induced the Cx43 expression of SV-HFO cells, as revealed by Northern blot analysis and immunocytochemistry. These modulators also increased gap junctional intercellular communication, in terms of the extent of dye transfer. On the other hand, 1 alpha, 25-dihydroxyvitamin D3 did not influence the Cx43 expression and gap junctional intercellular communication of the cells. These results suggest that RA and TGF-beta might maintain bone tissue as an organized tissue in vivo by increasing intercellular communication of osteoblastic cells.
Department of Pathology, Sapporo Medical University School of Medicine, Japan.
H
H
Chiba
N
N
Sawada
M
M
Oyamada
T
T
Kojima
K
K
Iba
S
S
Ishii
M
M
Mori
D002117:Calcitriol / Q000494:pharmacology*; D002450:Cell Communication / Q000187:drug effects*; D002461:Cell Line, Transformed; D018031:Connexin 43 / Q000096:biosynthesis*; D004121:Dimethyl Sulfoxide / Q000494:pharmacology; D000431:Ethanol / Q000494:pharmacology; D017629:Gap Junctions / Q000187:drug effects*; D005786:Gene Expression Regulation / Q000187:drug effects*; D006801:Humans; D010006:Osteoblasts / Q000187:drug effects* / Q000502:physiology; D013539:Simian virus 40; D016212:Transforming Growth Factor beta / Q000494:pharmacology*; D014212:Tretinoin / Q000494:pharmacology*
D018031:Connexin 43; D016212:Transforming Growth Factor beta; D000431:Ethanol; D014212:Tretinoin; D002117:Calcitriol; D004121:Dimethyl Sulfoxide