TY - JOUR
T1 - Mechanisms involved in inhibition of chondrogenesis by activin-A
AU - Mitsugi, Sho
AU - Ariyoshi, Wataru
AU - Okinaga, Toshinori
AU - Kaneuji, Takeshi
AU - Kataoka, Yoshihiro
AU - Takahashi, Tetsu
AU - Nishihara, Tatsuji
PY - 2012/4/6
Y1 - 2012/4/6
N2 - Objectives: Activin-A, a member of the TGF-β family, is known to be present in bone and cartilage. Although, involvement of the TGF-β family in chondrogenesis has been reported, the mechanism by which activin-A regulates chondrogenesis has not been fully elucidated. The aim of this study was to investigate the effects of activin-A on chondrocyte differentiation in vitro. Materials and methods: Monolayer cultures of mouse chondrocyte ATDC cells were pretreated with a variety of inhibitors of major signaling pathways prior to addition of activin-A. The expressions of sox9, runx2, and osterix mRNA were detected using real-time PCR. To determine chondrocyte differentiation, sulfated glycosaminoglycans were stained with Alcian blue. To further elucidate the role of activin-A on chondrogenesis regulation, phosphorylation of Smad2/3, ERK, JNK, and Akt proteins was determined by western blotting. Results: Activin-A suppressed the transcription of sox9, runx2, and osterix mRNA, as well as sulfated glycosaminoglycans accumulation. Activin-A also inhibited constitutive phosphorylation of JNK and Akt proteins. Furthermore, inhibition of the JNK and PI3K-Akt pathways by chemical inhibitors suppressed chondrogenesis in ATDC5 cells. Conclusions: These results indicate that activin-A may suppress chondrocyte differentiation in ATDC5 cells via down-regulation of JNK and Akt phosphorylation.
AB - Objectives: Activin-A, a member of the TGF-β family, is known to be present in bone and cartilage. Although, involvement of the TGF-β family in chondrogenesis has been reported, the mechanism by which activin-A regulates chondrogenesis has not been fully elucidated. The aim of this study was to investigate the effects of activin-A on chondrocyte differentiation in vitro. Materials and methods: Monolayer cultures of mouse chondrocyte ATDC cells were pretreated with a variety of inhibitors of major signaling pathways prior to addition of activin-A. The expressions of sox9, runx2, and osterix mRNA were detected using real-time PCR. To determine chondrocyte differentiation, sulfated glycosaminoglycans were stained with Alcian blue. To further elucidate the role of activin-A on chondrogenesis regulation, phosphorylation of Smad2/3, ERK, JNK, and Akt proteins was determined by western blotting. Results: Activin-A suppressed the transcription of sox9, runx2, and osterix mRNA, as well as sulfated glycosaminoglycans accumulation. Activin-A also inhibited constitutive phosphorylation of JNK and Akt proteins. Furthermore, inhibition of the JNK and PI3K-Akt pathways by chemical inhibitors suppressed chondrogenesis in ATDC5 cells. Conclusions: These results indicate that activin-A may suppress chondrocyte differentiation in ATDC5 cells via down-regulation of JNK and Akt phosphorylation.
KW - Activin-A
KW - Akt
KW - Chondrocyte
KW - JNK
KW - Smad
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U2 - 10.1016/j.bbrc.2012.03.003
DO - 10.1016/j.bbrc.2012.03.003
M3 - Article
C2 - 22425773
AN - SCOPUS:84862788113
VL - 420
SP - 380
EP - 384
JO - Biochemical and Biophysical Research Communications
JF - Biochemical and Biophysical Research Communications
SN - 0006-291X
IS - 2
ER -