Part of this work was presented in abstract form at the 18th annual meeting of the American Society for Bone and Mineral Research, Seattle, WA, U.S.A., September 7–11, 1996, abstract M341.
Cyclic Stretch Enhances Gap Junctional Communication Between Osteoblastic Cells†
Version of Record online: 1 FEB 1998
Copyright © 1998 ASBMR
Journal of Bone and Mineral Research
Volume 13, Issue 2, pages 218–228, February 1998
How to Cite
Ziambaras, K., Lecanda, F., Steinberg, T. H. and Civitelli, R. (1998), Cyclic Stretch Enhances Gap Junctional Communication Between Osteoblastic Cells. J Bone Miner Res, 13: 218–228. doi: 10.1359/jbmr.19184.108.40.206
- Issue online: 4 DEC 2009
- Version of Record online: 1 FEB 1998
- Manuscript Accepted: 26 SEP 1997
- Manuscript Revised: 2 SEP 1997
- Manuscript Received: 6 MAY 1997
Mechanical loading is essential to maintain skeletal integrity. Because gap junctions in bone are affected by mechanical factors, we studied whether stretch, an anabolic stimulus for osteoblasts, modulates direct intercellular communication in these cells. Gap junctional communication during stretch was assessed using a newly developed method, the “parachute assay,” which allows monitoring of dye diffusion without disruption of the plasma membrane. Application of cyclic stretch for 2 or 24 h to well-coupled ROS 17/2.8 cells resulted in a 56.5% and 30.4% increase in dye coupling, respectively, compared with resting conditions. Stretch increased dye diffusion less dramatically (12.4% compared with unstimulated cells) in the poorly coupled UMR 106-01 cells. The stretch-induced increase of cell coupling was abolished in the presence of the gap junctional inhibitor, heptanol. Steady-state mRNA levels of connexin43 (Cx43), the gap junction protein that mediates cell-to-cell diffusion of negatively charged dyes between osteoblasts, were not different between control and stretched ROS 17/2.8 or UMR 106-01 cultures after various periods of cyclic stretch. However, phosphorylated forms of Cx43 protein were more abundant in stretched ROS 17/2.8 than in controls. This was associated with increased punctate Cx43-specific immunostain at appositional membranes of stretched cells. Thus, cyclic stretch increases gap junctional communication between osteoblastic cells by modulating intracellular localization of Cx43.