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Low‐intensity pulsed ultrasound (LIPUS) induces RANKL, MCP‐1, and MIP‐1β expression in osteoblasts through the angiotensin II type 1 receptor
Author(s) -
Bandow Kenjiro,
Nishikawa Yoshiaki,
Ohnishi Tomokazu,
Kakimoto Kyoko,
Soejima Kazuhisa,
Iwabuchi Sadahiro,
Kuroe Kazuto,
Matsuguchi Tetsuya
Publication year - 2007
Publication title -
journal of cellular physiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.529
H-Index - 174
eISSN - 1097-4652
pISSN - 0021-9541
DOI - 10.1002/jcp.20944
Subject(s) - rankl , low intensity pulsed ultrasound , chemistry , chemokine , bone remodeling , monocyte , microbiology and biotechnology , receptor , osteoblast , osteoprotegerin , angiotensin ii receptor type 1 , cytokine , mapk/erk pathway , signal transduction , endocrinology , medicine , angiotensin ii , activator (genetics) , biology , therapeutic ultrasound , biochemistry , in vitro , radiology , ultrasound
Constant mechanical stress is essential for the maintenance of bone mass and strength, which is achieved through the cooperative functions of osteoblasts and osteoclasts. However, it has not been fully elucidated how these cell types mediate mechanical signals. Low‐intensity pulsed ultrasound (LIPUS) therapy is a recently developed method for application of mechanical stress, and is used clinically to promote bone fracture healing. In the present study, we applied LIPUS to osteoblasts at different stages of maturation and analyzed their chemokine and cytokine expression. In comparison with their immature counterparts, mature osteoblasts expressed significantly higher levels of mRNAs for the receptor activator of nuclear factor kappa B ligand (RANKL), monocyte chemoattractant protein (MCP)‐1, and macrophage‐inflammatory protein (MIP)‐1β after a few hours of LIPUS treatment. Intriguingly, protein and mRNA expression of angiotensin II type 1 receptor (AT1), a known mechanoreceptor in cardiomyocytes, was detected in osteoblasts, and the level of expression increased significantly during cell maturation. Furthermore, LIPUS‐induced extracellular signal‐regulated kinase (ERK) phosphorylation and RANKL/chemokine expression was abrogated by a specific AT1 inhibitor. Thus, AT1 may play one of the essential roles in bone metabolism as a mechanoreceptor of osteoblasts. J. Cell. Physiol. 211: 392–398, 2007. © 2006 Wiley‐Liss, Inc.