|Osteocytic network is more responsive in calcium signaling than osteoblastic network under fluid flow|
|Lu XL; Huo B(霍波); Chiang V; Guo XE; Guo, XE; Columbia Univ, Dept Biomed Engn, Bone Bioenn Lab, 351 Engn Terrace,Mail Code 8904,1210 Amsterdam Av, New York, NY 10027 USA.
|Source Publication||JOURNAL OF BONE AND MINERAL RESEARCH
|Abstract||Osteocytes, regarded as the mechanical sensor in bone, respond to mechanical stimulation by activating biochemical pathways and mediating the cellular activities of other bone cells. Little is known about how osteocytic networks respond to physiological mechanical stimuli. In this study, we compared the mechanical sensitivity of osteocytic and osteoblastic networks under physiological-related fluid shear stress (0.5 to 4?Pa). The intracellular calcium ([Ca2+]i) responses in micropatterned in vitro osteoblastic or osteocytic networks were recorded and analyzed. Osteocytes in the network showed highly repetitive spikelike [Ca2+]i peaks under fluid flow stimulation, which are dramatically different from those in the osteoblastic network. The number of responsive osteocytes in the network remained at a constant high percentage (>95%) regardless of the magnitude of shear stress, whereas the number of responsive osteoblasts in the network significantly depends on the strength of fluid flow. All spatiotemporal parameters of calcium signaling demonstrated that osteocytic networks are more sensitive and dynamic than osteoblastic networks, especially under low-level mechanical stimulations. Furthermore, pathway studies were performed to identify the molecular mechanisms responsible for the differences in [Ca2+]i signaling between osteoblastic and osteocytic networks. The results suggested that the T-type voltage-gated calcium channels (VGCC) expressed on osteocytes may play an essential role in the unique kinetics of [Ca2+]i signaling in osteocytic networks, whereas the L-type VGCC is critical for both types of cells to release multiple [Ca2+]i peaks. The extracellular calcium source and intracellular calcium store in ER-, ATP-, PGE2-, NO-, and caffeine-related pathways are found to play similar roles in the [Ca2+]i signaling for both osteoblasts and osteocytes. The findings in this study proved that osteocytic networks possess unique characteristics in sensing and processing mechanical signals.|
Bone Cell Networks
|Funding Organization||This work was supported by National Institutes of Health (NIH) grants R21 AR052417, R01 AR052461, and RC1 AR058453 (XEG). We acknowledge the contribution of Dr. PuiLeng Isabel Leong for her help in PLC inhibition experiments. We thank Dr. L Bonewald for her generous gift of MLO-Y4 cells.
|Corresponding Author||Guo, XE; Columbia Univ, Dept Biomed Engn, Bone Bioenn Lab, 351 Engn Terrace,Mail Code 8904,1210 Amsterdam Av, New York, NY 10027 USA.|
Lu XL,Huo B,Chiang V,et al. Osteocytic network is more responsive in calcium signaling than osteoblastic network under fluid flow[J]. JOURNAL OF BONE AND MINERAL RESEARCH,2012,27(3):563-574.
Lu XL,Huo B,Chiang V,Guo XE,Guo, XE,&Columbia Univ, Dept Biomed Engn, Bone Bioenn Lab, 351 Engn Terrace,Mail Code 8904,1210 Amsterdam Av, New York, NY 10027 USA..(2012).Osteocytic network is more responsive in calcium signaling than osteoblastic network under fluid flow.JOURNAL OF BONE AND MINERAL RESEARCH,27(3),563-574.
Lu XL,et al."Osteocytic network is more responsive in calcium signaling than osteoblastic network under fluid flow".JOURNAL OF BONE AND MINERAL RESEARCH 27.3(2012):563-574.
Items in the repository are protected by copyright, with all rights reserved, unless otherwise indicated.