Effects of high frequency loading on RANKL and OPG mRNA expression in ST-2 murine stromal cells

Chi Hyun Kim, Kyunghwan Kim, Christopher R. Jacobs

Research output: Contribution to journalArticle

6 Citations (Scopus)

Abstract

Background. Oscillatory fluid flow (OFF)-induced shear stress leads to positive bone remodeling through pro-formative and anti-resorptive effects on bone cells. In this study, the effects of high frequency OFF on expression of receptor activator of NF-B ligand (RANKL) and osteoprotegerin (OPG), two important regulators of osteoclast differentiation, were investigated. Methods. Cells were exposed to 1 Pa peak shear stress using three loading frequencies (1, 10, and 20 Hz) widely employed in cell, animal, and clinical studies of bone remodeling. Two separate experiments were performed where either the total number of cycles (3600 cycles) or the total loading time (60 min) was kept constant. Real-time RT-PCR was used to quantify mRNA levels of RANKL, OPG. Results. 3600 cycles of OFF at 1 Hz and 10 Hz loading decreased RANKL/OPG ratio. Interestingly, these results were due to different mechanisms where at 1 Hz the decrease was due to an increase in OPG mRNA, whereas at 10 Hz the decrease was due to a decrease in RANKL mRNA. Conclusion. Although high frequency OFF does not appear to further enhance the decrease in the RANKL/OPG ratio, these results suggest a potential to differentially control the change in either RANKL or OPG mRNA expression by applying different loading frequencies.

Original languageEnglish
Article number109
JournalBMC Musculoskeletal Disorders
Volume10
Issue number1
DOIs
Publication statusPublished - 2009 Sep 21

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Osteoprotegerin
Stromal Cells
Messenger RNA
Bone Remodeling
RANK Ligand
Osteoclasts
Real-Time Polymerase Chain Reaction
Bone and Bones

All Science Journal Classification (ASJC) codes

  • Rheumatology
  • Orthopedics and Sports Medicine

Cite this

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title = "Effects of high frequency loading on RANKL and OPG mRNA expression in ST-2 murine stromal cells",
abstract = "Background. Oscillatory fluid flow (OFF)-induced shear stress leads to positive bone remodeling through pro-formative and anti-resorptive effects on bone cells. In this study, the effects of high frequency OFF on expression of receptor activator of NF-B ligand (RANKL) and osteoprotegerin (OPG), two important regulators of osteoclast differentiation, were investigated. Methods. Cells were exposed to 1 Pa peak shear stress using three loading frequencies (1, 10, and 20 Hz) widely employed in cell, animal, and clinical studies of bone remodeling. Two separate experiments were performed where either the total number of cycles (3600 cycles) or the total loading time (60 min) was kept constant. Real-time RT-PCR was used to quantify mRNA levels of RANKL, OPG. Results. 3600 cycles of OFF at 1 Hz and 10 Hz loading decreased RANKL/OPG ratio. Interestingly, these results were due to different mechanisms where at 1 Hz the decrease was due to an increase in OPG mRNA, whereas at 10 Hz the decrease was due to a decrease in RANKL mRNA. Conclusion. Although high frequency OFF does not appear to further enhance the decrease in the RANKL/OPG ratio, these results suggest a potential to differentially control the change in either RANKL or OPG mRNA expression by applying different loading frequencies.",
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Effects of high frequency loading on RANKL and OPG mRNA expression in ST-2 murine stromal cells. / Kim, Chi Hyun; Kim, Kyunghwan; Jacobs, Christopher R.

In: BMC Musculoskeletal Disorders, Vol. 10, No. 1, 109, 21.09.2009.

Research output: Contribution to journalArticle

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