Quercetin Partially Preserves Development of Osteoblast Phenotype in Fetal Rat Calvaria Cells in an Oxidative Stress Environment

Abstract

Studies are needed to improve understanding of the osteoblast antioxidant response, and the balance between oxidative homeostasis and osteoblast differentiation. The flavonol quercetin aglycone (QRC) up-regulates the osteoblast antioxidant response in vitro without suppressing osteoblast phenotype, suggesting that QRC may preserve osteoblast phenotypic development in cells subsequently exposed to oxidative stress, which suppresses osteoblast differentiation. The aims of this study were to assess the extent that QRC pretreatment preserved development of the osteoblast phenotype in cells subsequently cultured with hydrogen peroxide, an oxidative stressor, and to characterize alterations in the osteoblast antioxidant response and in key antioxidant signaling pathways. We hypothesized that pretreatment with QRC would preserve phenotypic development after hydrogen peroxide treatment, suppress the hydrogen peroxide-induced antioxidant response, and that the antioxidant response would involve alterations in Nrf2 and ERK1/2 signaling. Results showed that treating fetal rat calvarial osteoblasts for 4 days (D5-9) with 300 μM hydrogen peroxide resulted in fewer alkaline phosphatase-positive cells and mineralized nodules, altered cell morphology, and significantly lower osteoblast phenotypic gene expression (P < 0.05). This suppression was partially blocked when cells were pretreated 12 h with 20 μM QRC. Hydrogen peroxide also produced sustained up-regulation of heme oxygenase-1 (HO-1) and γ-glutamate cysteine ligase catalytic subunit (GCLC), which was partially blocked in hydrogen peroxide-treated cells that first received QRC pretreatment. The alterations in the antioxidant stress response coincided with alterations in phosphorylated ERK1/2, but not Nrf2. These results suggest that QRC suppresses hydrogen peroxide-induced activation of the antioxidant response, and partially preserves osteoblast phenotypic development. J. Cell. Physiol. 231: 2779-2788, 2016. © 2016 Wiley Periodicals, Inc.

Quercetin as an Agent for Protecting the Bone: A Review of the Current Evidence

“…In the subsequent year, the same group of investigators cultured osteoblasts from fetal rat calvaria in the presence of an oxidative stressor (H 2 O 2 ) and treated them with quercetin aglycone. Sustained upregulation of HO-1 and GCLC was observed in osteoblasts without treatment, but it was blocked by the addition of quercetin aglycone [80]. At this juncture, it might be postulated that these increases in HO-1 and GCLC expression might be due to the need to counteract the overwhelming oxidative response induced by H 2 O 2 .…”

“…Quercetin C-glucoside (10 or 100 µM) stimulated ALP activity, mineralisation, Runx-2, BMP-2, osteocalcin, and COL1 in rat calvarial osteoblasts and bone marrow cells [33]. Quercetin aglycone (20 µM) increased mineralised nodules, ALP, Runx-2, BSP and osteocalcin in osteoblasts isolated from fetal rat calvaria treated with H 2 O 2 [80]. Exposure of human osteoblast-like SaOS-2 cells with quercetin 3-β-D-glucoside and polyphosphate caused upregulation of Runx-2 and its co-activators (activating transcription factor 6 (ATF6) and Ets oncogene homolog 1 (Ets1)) [81].…”

Characteristics and biologic effects of thermosensitive quercetin‐chitosan/collagen hydrogel on human periodontal ligament stem cells

“…25 mM hydrogen peroxide for 45 min. After that cell viability assay was performed as described in section 2.15 Cytotoxicity test ( n = 5, Mean ± SD ) 30,31 …”

The Role of NRF2 in Bone Metabolism – Friend or Foe?

“…Although NRF2 inhibition alleviates the radiation-induced osteogenic differentiation and mineralization damage, ZnPP IX, an inhibitor of HO-1, significantly restored radiation-induced osteogenic damage without inhibiting radiation-mediated activation of NRF2 ( 33 ). Quercetin alleviates H 2 O 2 -induced damage to osteoblast differentiation by downregulating HO-1 without effecting on NRF2 expression ( 37 ). These data suggest that the relationship between osteoblastogenesis and NRF2/HO-1 or ROS is rather complex ( Figure 2 ), and HO-1 may be a bigger culprit of oxidative stress-induced osteogenic injury.…”