J Dent Hyg Sci.  2019 Sep;19(3):198-204. 10.17135/jdhs.2019.19.3.198.

Protective Effects of Ursolic Acid on Osteoblastic Differentiation via Activation of IER3/Nrf2

• Lee SI

• KMID: 2460998
• DOI: http://doi.org/10.17135/jdhs.2019.19.3.198

Abstract

BACKGROUND
Oxidative stress is a known to be associated with in the pathogenesis of many inflammatory diseases, including periodontitis. Ursolic acid is a pentacyclic triterpenoid with has antimicrobial, antioxidative, and anticancer properties. However, the role of ursolic acid in the regulating of osteogenesis remains undetermined. This study was aimed to elucidate the crucial osteogenic effects of ursolic acid and its ability to inhibit oxidative stress by targeting the immediate early response 3 (IER3)/nuclear factor erythroid 2-related factor 2 (Nrf2) pathway.
METHODS
Cell proliferation was determined using water-soluble tetrazolium salt assay, cell differentiation was evaluated by alkaline phosphatase (ALP) activity, and formation of calcium nodules was detected using alizarin red S stain. Generation of reactive oxygen species (ROS) was determined using by DCFH-DA fluorescence dye in hydrogen peroxide (Hâ‚‚Oâ‚‚2)-treated MG-63 cells. Expression levels of IER3, Nrf2, and heme oxygenase-1 (HO-1) were analyzed using western blot analysis.
RESULTS
Our results showed that ursolic acid up-regulated the proliferation of osteoblasts without any cytotoxic effects, and promoted ALP activity and mineralization. Hâ‚‚Oâ‚‚-induced ROS generation was found to be significantly inhibited on treatment with ursolic acid. Furthermore, in Hâ‚‚Oâ‚‚-treated cells, the expression of the early response genes: IER3, Nrf2, and Nrf2-related phase II enzyme (HO-1) was enhanced in the presence of ursolic acid.
CONCLUSION
The key findings of the present study elucidate the protective effects of ursolic acid against oxidative stress conditions in osteoblasts via the IER3/Nrf2 pathway. Thus, ursolic acid may be developed as a preventative and therapeutic agent for mineral homeostasis and inflammatory diseases caused due to oxidative injury.

Keyword

Immediate early response 3 protein; NF-E2-related factor 2; Osteoblast; Oxidative stress; Periodontal disease

MeSH Terms

Alkaline Phosphatase
Blotting, Western
Calcium
Cell Differentiation
Cell Proliferation
Fluorescence
Heme Oxygenase-1
Homeostasis
Hydrogen Peroxide
Miners
NF-E2-Related Factor 2
Osteoblasts*
Osteogenesis
Oxidative Stress
Periodontal Diseases
Periodontitis
Reactive Oxygen Species
Alkaline Phosphatase
Calcium
Heme Oxygenase-1
Hydrogen Peroxide
NF-E2-Related Factor 2
Reactive Oxygen Species