Effects of reactive oxygen species (ROS) on antioxidant system and osteoblastic differentiation in MC3T3-E1 cells
Masato Arai1, Yasuko Shibata, Kamolparn Pugdee
1Department of Periodontology, Nihon University School of Dentistry at Matsudo, 2-870-1 Sakaecho-Nishi, Matsudo, Chiba 271-8587, Japan.
Abstract:
Oxidative stress regulates cellular functions in multiple pathological conditions, including bone formation by osteoblastic cells. However, little is known about the cellular mechanisms responsible for the effects of oxidative stress on osteoblast functions in senescence. To clarify the inhibitory effects of oxidative stress on osteoblastic mineralization, we examined the relationship between the antioxidant system and bone formation in MC3T3-E1 cells. After a single exposure to H2O2 within range of a non-toxic concentration for cells, the mineralization level was diminished half. Under the same conditions, gene expression of the transcription factor Nrf2, which regulates antioxidant enzymes, was up-regulated. In addition, gene expression for the osteogenic markers Runx2, ALP, and BSP was lower than that in non-treated cells, whereas expression of the osteocalcin gene was up-regulated following H2O2 exposure. These results suggest that reduced mineralization by MC3T3-E1 cells after H2O2 exposure is the result of an up-regulated antioxidant system and altered osteogenic gene expression.
Insights
Oxidative stress impairs bone formation in osteoblastic cells. Hydrogen peroxide exposure reduced mineralization by up-regulating the antioxidant system and altering key osteogenic gene expression.
Area of Science:
- Cell Biology
- Biochemistry
- Biomedical Science
Background:
- Oxidative stress impacts cellular functions in various diseases, including bone formation by osteoblasts.
- Mechanisms linking oxidative stress to osteoblast dysfunction, particularly during senescence, remain poorly understood.
Purpose of the Study:
- To investigate the inhibitory effects of oxidative stress on osteoblastic mineralization.
- To examine the relationship between the antioxidant system and bone formation in MC3T3-E1 cells under oxidative stress.
Main Methods:
- MC3T3-E1 cells were exposed to hydrogen peroxide (H2O2) at non-toxic concentrations.
- Mineralization levels were assessed.
- Gene expression of the antioxidant regulator Nrf2 and osteogenic markers (Runx2, ALP, BSP, osteocalcin) was analyzed.
Main Results:
- A single H2O2 exposure halved the mineralization level in MC3T3-E1 cells.
- Gene expression of Nrf2 was upregulated, indicating activation of the antioxidant system.
- Expression of osteogenic markers Runx2, ALP, and BSP decreased, while osteocalcin expression increased.
Conclusions:
- Reduced mineralization in osteoblasts exposed to H2O2 is associated with an activated antioxidant system.
- Altered expression of key osteogenic genes contributes to the impaired bone formation under oxidative stress.
