Transforming growth factor-beta (TGF-beta) and articular chondrocytes.
Transforming growth factor-beta (TGF-beta) has a dual effect on the proliferation of joint chondrocytes. In medium with a low serum concentration, it inhibits cell growth, while in medium supplemented with 10% fetal calf serum it stimulates cell growth. This stimulation leads to a higher replication rate an a larger number of cells in the G2/M phase of the cell cycle. Since these cells have already replicated their DNA, they can begin mitosis when stimulated by a EGF type factor. This mechanism involves the systems of the TGF-beta receptors which appear to vary with the cell cycle. In addition, a glycane inositophosphate may play a role as a second messenger for TGG-beta in this action. Finally, TGF-beta cannot restore the chondrocyte phenotype in dedifferentiated cells nor limit the dedifferentiation process. It exerts a opposing effect to the deleterious effects of interleukin-1 by inhibiting the expression of the receptors of this cytokine at the level of transcription. These in vitro effects would suggest that TGF-beta plays an important role in the repair potentiality of joint cartilage especially in arthrosis. In vivo studies are however necessary to verify this hypothesis.
Pujol
J P
JP
Laboratoire de Biochimie du Tissu Conjonctif (CJF INSERM 91-06), CHU Côte de Nacre, Caen.
Galera
P
P
Pronost
S
S
Boumediene
K
K
Vivien
D
D
Macro
M
M
Min
W
W
Redini
F
F
Penfornis
H
H
Daireaux
M
M
D000818:Animals; D002358:Cartilage, Articular / Q000166:cytology*; D002455:Cell Division / Q000187:drug effects; D005109:Extracellular Matrix / Q000378:metabolism; D016195:G2 Phase; D007375:Interleukin-1 / Q000037:antagonists & inhibitors; D011817:Rabbits; D018125:Receptors, Transforming Growth Factor beta / Q000378:metabolism; D016212:Transforming Growth Factor beta / Q000494:pharmacology*
D007375:Interleukin-1; D018125:Receptors, Transforming Growth Factor beta; D016212:Transforming Growth Factor beta