Journal of Korean Orthopaedic Research Society  2007;10(2):65-75

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

Soo Bong HAHN 1 ; Min Sung PARK ; Yun Hee KIM ; Jin Woo LEE

Affiliations

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Keywords

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

Country

Republic of Korea

Language

Korean

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.