We assessed the characteristics of human osteoblasts, focusing on small GTPase Rho signaling. β1 Integrin were highly expressed on osteoblasts. Engagement of β1 integrins by type I collagen augmented expression of intercellular adhesion molecule 1 (ICAM-1) and receptor activator of nuclear factor κB ligand (RANKL) on osteoblasts. Rho was activated by β1 stimulation in osteoblasts. β1 Integrin-induced up-regulation of ICAM-1 and RANKL was inhibited by transfection with adenoviruses encoding C3 transferase or pretreated with Y-27632, specific Rho and Rho-kinase inhibitors. Engagement of β1 integrin on osteoblasts induced formation of tartrate-resistant acid phosphatase (TRAP)-positive multinuclear cells (MNC) in a coculture system of osteoblasts and peripheral monocytes, but this action was completely abrogated by transfection of C3 transferase. Our results indicate the direct involvement of Rho-mediated signaling in β1 integrin-induced up-regulation of ICAM-1 and RANKL and RANKL-dependent osteoclast maturation. Thus, Rho-mediated signaling in osteoblasts seems to introduce major biases to bone resorption.
|Number of pages||7|
|Journal||Biochemical and Biophysical Research Communications|
|Publication status||Published - Apr 27 2007|
All Science Journal Classification (ASJC) codes
- Molecular Biology
- Cell Biology