TY - JOUR
T1 - Calcium response in single osteocytes to locally applied mechanical stimulus
T2 - Differences in cell process and cell body
AU - Adachi, Taiji
AU - Aonuma, Yuki
AU - Tanaka, Mototsugu
AU - Hojo, Masaki
AU - Takano-Yamamoto, Teruko
AU - Kamioka, Hiroshi
N1 - Funding Information:
Monoclonal antibody OB7.3 was kindly provided by Jenneke Klein-Nulend and Cornelis M. Semeins (ACTA-Vrije University). FE-SEM observations were assisted by Laboratory for Electron Microcopy, Center for Anatomical Studies, Graduate School of Medicine, Kyoto University. This study was partially supported by the Grants-in-Aid for Specially Promoted Research (20001007) from the Ministry of Education, Culture, Sports, Science and Technology, Japan, and by the Japan Society for the Promotion of Science under the Research Fellowships for Young Scientists.
PY - 2009/8/25
Y1 - 2009/8/25
N2 - It is proposed that osteocytes embedded in the bone matrix have the ability to sense deformation and/or damage to the matrix and to feed these mechanical signals back to the adaptive bone remodeling process. When osteoblasts differentiate into osteocytes during the bone formation process, they change their morphology to a stellate form with many slender processes. This characteristic cell shape may underlie the differences in mechanosensitivity between the cell processes and cell body. To elucidate the mechanism of cellular response to mechanical stimulus in osteocytes, we investigated the site-dependent response to quantitatively controlled local mechanical stimulus in single osteocytes isolated from chick embryos, using the technique of calcium imaging. A mechanical stimulus was applied to a single osteocyte using a glass microneedle targeting a microparticle adhered to the cell membrane by modification with a monoclonal antibody OB7.3. Application of the local deformation induced calcium transients in the vicinity of the stimulated point and caused diffusive wave propagation of the calcium transient to the entire intracellular region. The rate of cell response to the stimulus was higher when applied to the cell processes than when applied to the cell body. In addition, a large deformation was necessary at the cell body to induce calcium transients, whereas a relatively small deformation was sufficient at the cell processes, suggesting that the mechanosensitivity of the cell processes was higher than that of the cell body. These results suggest that the cell shape with slender processes contributes to the site-dependent mechanosensitivity in osteocytes.
AB - It is proposed that osteocytes embedded in the bone matrix have the ability to sense deformation and/or damage to the matrix and to feed these mechanical signals back to the adaptive bone remodeling process. When osteoblasts differentiate into osteocytes during the bone formation process, they change their morphology to a stellate form with many slender processes. This characteristic cell shape may underlie the differences in mechanosensitivity between the cell processes and cell body. To elucidate the mechanism of cellular response to mechanical stimulus in osteocytes, we investigated the site-dependent response to quantitatively controlled local mechanical stimulus in single osteocytes isolated from chick embryos, using the technique of calcium imaging. A mechanical stimulus was applied to a single osteocyte using a glass microneedle targeting a microparticle adhered to the cell membrane by modification with a monoclonal antibody OB7.3. Application of the local deformation induced calcium transients in the vicinity of the stimulated point and caused diffusive wave propagation of the calcium transient to the entire intracellular region. The rate of cell response to the stimulus was higher when applied to the cell processes than when applied to the cell body. In addition, a large deformation was necessary at the cell body to induce calcium transients, whereas a relatively small deformation was sufficient at the cell processes, suggesting that the mechanosensitivity of the cell processes was higher than that of the cell body. These results suggest that the cell shape with slender processes contributes to the site-dependent mechanosensitivity in osteocytes.
KW - Bone cells
KW - Calcium signaling response
KW - Cell biomechanics
KW - Mechanical stimulus
KW - Mechanotransduction
KW - Osteocytes
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U2 - 10.1016/j.jbiomech.2009.04.034
DO - 10.1016/j.jbiomech.2009.04.034
M3 - Article
C2 - 19625024
AN - SCOPUS:68249137198
SN - 0021-9290
VL - 42
SP - 1989
EP - 1995
JO - Journal of Biomechanics
JF - Journal of Biomechanics
IS - 12
ER -