J Korean Orthop Res Soc.  2007 Oct;10(2):65-75.

Cross-talk between Integrin and SMAD Signal Pathway in Articular Chondrocyte

• Hahn SB
• Park MS
• Kim YH
• Lee JW

Abstract

PURPOSE: Identifying the signal cross-talk between integrin signaling cascade and TGF-beta 1 signaling cascade in articular chondrocytes.
MATERIALS AND METHODS
To analyze integrin or TGF-beta 1 mediated signaling pathways from extracellular stimuli, type II collagen was coated on the cell culture plate and TGF-beta 1 was added to cell culture media. Chondrocytes were cultured in the conditioned media with each or both stimuli. Altered activation of signaling proteins detected with western blot technique.
RESULTS
More rapid attachment of cells was observed in the type II collagen coated group than non-coated group. The phosphorylated SMAD 2 and 3 were expressed in the type II collagen coated group and synergistically up-regulated phosphorylation in the co-treated group. The phosphorylated FAK at tyrosine 925 was activated by TGF-beta 1 treatment and synergistically up-regulated by both stimuli. But there was no meaningfully changed phosphorylation of extracellular signal regulated protein kinase (ERK) 1/2 and p38, as known downstream molecules of FAK cascade.
CONCLUSION
This result means that SMAD 2, SMAD 3 and tyrosine 925 of FAK are involved in this signal cross-talking in articular chondrocytes.

Keyword

Articular chondrocyte; Signal cross-talk; Type II collagen; TGF-beta 1; FAK; SMAD 2/3

MeSH Terms

Blotting, Western
Cell Culture Techniques
Chondrocytes*
Collagen Type II
Culture Media, Conditioned
Phosphorylation
Protein Kinases
Signal Transduction*
Transforming Growth Factor beta
Tyrosine
Collagen Type II
Culture Media, Conditioned
Protein Kinases
Transforming Growth Factor beta
Tyrosine