This work was presented in part at the 24th Annual Meeting of the American Society for Bone and Mineral Research, San Antonio, TX, USA, September 20-24, 2002.The authors have no conflict of interest.
Biphasic Effect of Prostaglandin E2 on Osteoclast Formation in Spleen Cell Cultures: Role of the EP2 Receptor†
Article first published online: 25 OCT 2004
Copyright © 2005 ASBMR
Journal of Bone and Mineral Research
Volume 20, Issue 1, pages 23–29, January 2005
How to Cite
Ono, K., Kaneko, H., Choudhary, S., Pilbeam, C. C., Lorenzo, J. A., Akatsu, T., Kugai, N. and Raisz, L. G. (2005), Biphasic Effect of Prostaglandin E2 on Osteoclast Formation in Spleen Cell Cultures: Role of the EP2 Receptor. J Bone Miner Res, 20: 23–29. doi: 10.1359/JBMR.041027
- Issue published online: 4 DEC 2009
- Article first published online: 25 OCT 2004
- Manuscript Accepted: 3 AUG 2004
- Manuscript Revised: 16 JUN 2004
- Manuscript Received: 24 NOV 2003
- prostaglandin receptors;
- macrophage-colony-stimulating factor
We examined the effect of PGE2 on OC formation from spleen cells treated with M-CSF and RANKL. PGE2 decreased OC number at 5–6 days of culture and increased OC number, size, and resorptive activity at 7–8 days. A selective EP2 receptor agonist mimicked these effects. Deletion of the EP2 receptor or depletion of T-cells abrogated the increase in OC number.
Introduction: Prostaglandin E2 (PGE2) has been reported to increase osteoclast (OC) number in spleen cells cultured with RANKL and macrophage-colony-stimulating factor (M-CSF). In this study, we examined the time course of PGE2 effects on spleen cells cultured with RANKL and M-CSF. We then investigated which PGE receptors and cell types were involved in these effects.
Materials and Methods: Spleen cells were cultured from wildtype C57BL/6 mice and EP2 or EP4 receptor-deficient (−/−) and wildtype (+/+) mice on a mixed genetic background. Spleen cells were cultured with M-CSF and RANKL for 5–9 days with or without PGE2 or selective agonists for the four PGE2 receptors (EP1A, EP2A, EP3A, or EP4A). Some cultures were performed using T-cell-depleted spleen cells. OC number and size were quantitated. OC apoptosis and pit formation were measured at 7 or 8 days.
Results: PGE2 decreased the number of OCs formed in the presence of RANKL and M-CSF at 5–6 days of culture and increased OC number at 8–9 days compared with cultures without PGE2. PGE2 also increased OC size at 7 and 8 days, decreased apoptosis of OC at 7 days, and increased pit formation at 8 days. EP1A or EP4A had no effect on OC. EP3A decreased OC number. EP2A mimicked effect of PGE2. EP2−/− spleen cells showed no increase in OC number in response to PGE2, whereas deletion of EP4 had no effect. Depletion of T-cells abrogated the late increase of OC number.
Conclusions: We conclude that PGE2 has an initial inhibitory effect on OC formation in spleen cell cultures, possibly mediated by both EP2 and EP3 receptors, and a later stimulatory effect, mediated by the EP2 receptor, possibly acting on T-cells.