J Korean Med Sci.  2019 Oct;34(41):e267. 10.3346/jkms.2019.34.e267.

Tetrabromobisphenol A Promotes the Osteoclastogenesis of RAW264.7 Cells Induced by Receptor Activator of NF-kappa B Ligand In Vitro

• Park SY
• Choi EM
• Suh KS
• Kim HS
• Chin SO
• Rhee SY
• Kim DY
• Oh S
• Chon S

• KMID: 2460925
• DOI: http://doi.org/10.3346/jkms.2019.34.e267

Abstract

BACKGROUND
Tetrabromobisphenol A (TBBPA), one of the most widely used brominated flame-retardants, is a representative persistent organic pollutants group. Studies on TBBPA toxicity have been conducted using various target cells; however, few studies have investigated TBBPA toxicity in bone cells. Therefore, this study investigated the in vitro effects of TBBPA on osteoclasts, a cell type involved in bone metabolism.
METHODS
RAW264.7 cells were cultured in medium containing 50 ng/mL receptor activator of nuclear factor kappa B ligand (RANKL) and varying concentrations of TBBPA. To evaluate the effects of TBBPA on the differentiation and function of osteoclasts, osteoclast-specific gene expression, tartrate-resistant acid phosphatase (TRAP) activity, bone resorbing activity, mitochondrial membrane potential (MMP) and mitochondrial superoxide were measured.
RESULTS
The presence of 20 μM TBBPA significantly increased TRAP activity in RANKL-stimulated RAW264.7 cells, the bone resorbing activity of osteoclasts, and the gene expression of Akt2, nuclear factor of activated T-cells cytoplasmic 1, and chloride channel voltage-sensitive 7. However, TBBPA treatment caused no change in the expression of carbonic anhydrase II, cathepsin K, osteopetrosis-associated transmembrane protein 1, Src, extracellular signal-related kinase, GAB2, c-Fos, or matrix metalloproteinase 9. Furthermore, 20 μM TBBPA caused a significant decrease in MMP and a significant increase in mitochondrial superoxide production.
CONCLUSION
This study suggests that TBBPA promotes osteoclast differentiation and activity. The mechanism of TBBPA-stimulated osteoclastogenesis might include increased expression of several genes involved in osteoclast differentiation and reactive oxygen species production.

Keyword

Mitochondrial Function; RAW264.7 Cells; Tetrabromobisphenol A; Osteoclastogenesis

MeSH Terms

Acid Phosphatase
Carbonic Anhydrase II
Cathepsin K
Chloride Channels
Cytoplasm
Gene Expression
In Vitro Techniques*
Matrix Metalloproteinase 9
Membrane Potential, Mitochondrial
Metabolism
Osteoclasts
Phosphotransferases
RANK Ligand
Reactive Oxygen Species
Receptor Activator of Nuclear Factor-kappa B*
Superoxides
T-Lymphocytes
Acid Phosphatase
Carbonic Anhydrase II
Cathepsin K
Chloride Channels
Matrix Metalloproteinase 9
Phosphotransferases
RANK Ligand
Reactive Oxygen Species
Receptor Activator of Nuclear Factor-kappa B
Superoxides