Interleukin-1 enhances the response of osteoblasts to platelet-derived growth factor through the alpha receptor-specific up-regulation.
Both platelet-derived growth factor (PDGF) and interleukin-1 (IL-1) are produced by activated macrophages and are thought to contribute to bone remodeling, but their precise roles remain to be clarified. The interaction between PDGF and IL-1 was, therefore, studied in normal osteoblast-like cells (MC3T3-E1). The expression of alpha- and beta-PDGF receptors on MC3T3-E1 cells was detected by RNA blot analysis and confirmed by immunoblot analysis. PDGF-induced chemotactic as well as mitogenic activities were synergistically enhanced by either IL-1 alpha or IL-1 beta (40 units/ml) pretreatment in serum-free medium, although IL-1 alone did not show any detectable chemotactic activities. This biological enhancement by IL-1 was accompanied by a selective increase of alpha-PDGF receptor expression, following the augmentation of alpha receptor autophosphorylation and inositol phosphate hydrolysis induced by PDGF-AA. These findings suggest that PDGF and IL-1 are jointly involved in the bone-remodeling microenvironment as local coupling factors.
Tsukamoto
T
T
Department of Medicine, Kobe University School of Medicine, Japan.
Matsui
T
T
Nakata
H
H
Ito
M
M
Natazuka
T
T
Fukase
M
M
Fujita
T
T
D015152:Blotting, Northern; D015153:Blotting, Western; D002460:Cell Line; D004591:Electrophoresis, Polyacrylamide Gel; D006801:Humans; D007295:Inositol Phosphates / Q000032:analysis; D007375:Interleukin-1 / Q000502:physiology*; D010006:Osteoblasts / Q000378:metabolism*; D010766:Phosphorylation; D010982:Platelet-Derived Growth Factor / Q000378:metabolism / Q000502:physiology*; D012313:RNA / Q000032:analysis; D011956:Receptors, Cell Surface / Q000378:metabolism*; D017479:Receptors, Platelet-Derived Growth Factor; D014443:Tyrosine / Q000378:metabolism; D015854:Up-Regulation
D007295:Inositol Phosphates; D007375:Interleukin-1; D010982:Platelet-Derived Growth Factor; D011956:Receptors, Cell Surface; D014443:Tyrosine; D012313:RNA; D017479:Receptors, Platelet-Derived Growth Factor