Parathyroid Hormone Modulates the Response of Osteoblast-Like Cells to Mechanical Stimulation
Rent the article at a discountRent now
* Final gross prices may vary according to local VAT.Get Access
Mechanical loading stimulates many responses in bone and osteoblasts associated with osteogenesis. Since loading and parathyroid hormone (PTH) activate similar signaling pathways in osteoblasts, we postulate that PTH can potentiate the effects of mechanical stimulation. Using an in vitro four-point bending device, we found that expression of COX-2, the inducible isoform of cyclooxygenase, was dependent on fluid forces generated across the culture plate, but not physiologic levels of strain in MC3T3-E1 osteoblast-like cells. Addition of 50 nM PTH during loading increased COX-2 expression at both subthreshold and threshold levels of fluid forces compared with either stimuli alone. We also demonstrated that application of fluid shear to MC3T3-E1 cells induced a rapid increase in [Ca2+]i. Although PTH did not significantly change [Ca2+]i levels, flow and PTH did produce a significantly greater [Ca2+]i response and increased the number of responding cells than is found in fluid shear alone. The [Ca2+]i response to these stimuli was significantly decreased when the mechanosensitive channel inhibitor, gadolinium, was present. These studies indicate that PTH increases the cellular responses of osteoblasts to mechanical loading. Furthermore, this response may be mediated by alterations in [Ca2+]i by modulating the mechanosensitive channel.
- Parathyroid Hormone Modulates the Response of Osteoblast-Like Cells to Mechanical Stimulation
Calcified Tissue International
Volume 67, Issue 3 , pp 241-246
- Cover Date
- Print ISSN
- Online ISSN
- Additional Links
- Key words: Osteoblasts — PTH — Prostaglandin — COX-2 — Mechanical loading.
- Industry Sectors
- Author Affiliations
- A1. Department of Physiology and Biophysics, Indiana University School of Medicine, Indianapolis, Indiana 46202, USA, US
- A2. Department of Orthopaedic Surgery, Indiana University School of Medicine, 541 Clinical Dr., Rm 600, Indianapolis, Indiana 46202-5111, USA, US