Small GTPase Rho signaling is involved in β1 integrin-mediated up-regulation of intercellular adhesion molecule 1 and receptor activator of nuclear factor κB ligand on osteoblasts and osteoclast maturation

Fumihiko Hirai, Shingo Nakayamada, Yosuke Okada, Kazuyoshi Saito, Hitoshi Kurose, Akira Mogami, Yoshiya Tanaka

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11 Citations (Scopus)

Abstract

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.

Original languageEnglish
Pages (from-to)279-285
Number of pages7
JournalBiochemical and Biophysical Research Communications
Volume356
Issue number1
DOIs
Publication statusPublished - Apr 27 2007

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All Science Journal Classification (ASJC) codes

  • Biophysics
  • Biochemistry
  • Molecular Biology
  • Cell Biology

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