Contrasting effects of triiodothyronine on heat shock protein 27 induction and vascular endothelial growth factor synthesis stimulated by TGF-beta in osteoblasts.
In osteoblast-like MC3T3-E1 cells, we recently reported that transforming growth factor-beta (TGF-beta) stimulates the induction of heat shock protein 27 (HSP27). In the present study, we investigated the effects of triiodothyronine (T(3)) on the TGF-beta-stimulated induction of HSP27 and synthesis of vascular endothelial growth factor (VEGF) in these cells. T(3) by itself had little effect on the level of HSP27, however, it significantly reduced the TGF-beta-stimulated HSP27 accumulation in a dose-dependent manner in the range between 1 pM and 100 nM. The TGF-beta-stimulated increase in the level of mRNA for HSP27 was also attenuated by T(3). On the other hand, T(3), which alone stimulated the release of VEGF, more than additively stimulated the TGF-beta-induced VEGF release. T(3) enhanced the TGF-beta-induced increase in the levels of mRNA for VEGF. These results strongly suggest that T(3) has contrasting effects on HSP27 induction and VEGF synthesis induced by TGF-beta in osteoblasts.
Tokuda
H
H
Department of Internal Medicine, Chubu National Hospital: National Institute for Longevity Sciences, Obu, Japan.
Kato
K
K
Oiso
Y
Y
Kozawa
O
O
D000818:Animals; D015152:Blotting, Northern; D002460:Cell Line; D004305:Dose-Response Relationship, Drug; D006360:Heat-Shock Proteins / Q000096:biosynthesis* / Q000235:genetics; D051379:Mice; D010006:Osteoblasts / Q000187:drug effects* / Q000378:metabolism; D012333:RNA, Messenger / Q000096:biosynthesis; D016212:Transforming Growth Factor beta / Q000494:pharmacology*; D014284:Triiodothyronine / Q000494:pharmacology*; D015854:Up-Regulation; D042461:Vascular Endothelial Growth Factor A / Q000096:biosynthesis* / Q000235:genetics
D006360:Heat-Shock Proteins; D012333:RNA, Messenger; D016212:Transforming Growth Factor beta; D042461:Vascular Endothelial Growth Factor A; D014284:Triiodothyronine