Effects of Ginger Phenylpropanoids and Quercetin on Nrf2-ARE Pathway in Human BJ Fibroblasts and HaCaT Keratinocytes

Abstract

Quercetin and phenylpropanoids are well known chemoprotective compounds identified in many plants. This study was aimed at determining their effects on activation of Nuclear factor erythroid 2-related factor 2 (Nrf2) antioxidant response element (Nrf2-ARE) signalling pathway and expression of its important downstream effector phase II detoxification enzyme glutathione-S-transferase P1 (GSTP1) in BJ foreskin fibroblasts and skin HaCaT keratinocytes. Cell lines and their corresponding Nrf2-ARE luciferase reporter cells were treated by ginger phenylpropanoids and quercetin for 10 h and the level of Nrf2 activity was subsequently determined. Both, ginger phenylpropanoids and quercetin, significantly increased the level of Nrf2 activity. Subsequent western blot analyses of proteins showed the increased expression level of glutathione-S-transferase P1 (GSTP1) in BJ cells but not in HaCaT cells. Such phenomenon of unresponsive downstream target expression in HaCaT cells was consistent with previous studies showing a constitutive expression of their GSTP1. Thus, while both ginger phenylpropanoids and quercetin have the property of increasing the level of Nrf2 both in HaCaT and in BJ cells, their effects on its downstream signalling were mediated only in BJ cells.

Optimal Concentrations and Synergistic Effects of Some Herbal Extracts on Viability of Dermal Fibroblasts

“…But phenylpropanoids and quercetin components of ginger resulted in protection against oxidative stress in human skin cells (32). Recent studies suggest that chamomile caused complete wound healing faster than corticosteroids (12).…”

Quercetin as an Emerging Anti-Melanoma Agent: A Four-Focus Area Therapeutic Development Strategy

“…In DB-1 melanoma cells overexpressing tyrosinase, quercetin administration led to significant increase of p53 protein and the number of cells in apoptosis compared to untreated cells (8). In particular, quercetin may potentiate p53-dependent apoptosis in melanocytic cells via stimulation of nuclear factor E2-related factor 2 (Nrf2) transcriptional activity, which has been observed in various cell types including human hepatoblastoma HepG2 cells (85, 86), human BJ foreskin fibroblasts and skin HaCaT keratinocytes (87), rat DI TNC1 astrocytes (88), and UVA-irradiated mouse B16F10 melanoma cells (89). Nrf2 is a basic leucine zipper (bZIP) transcription factor that induces the expression of several genes involved in cellular redox reactions, drug metabolism and transport, energy metabolism, and intracellular iron homeostasis in response to oxidative and electrophilic stress (90).…”

“…Quercetin has been demonstrated to induce Nrf2-mediated ARE activation in vitro in human hepatoblastoma HepG2 cells (85, 86), human BJ foreskin fibroblasts and skin HaCaT keratinocytes (87), rat DI TNC1 astrocytes (88), and UVA-irradiated mouse B16F10 melanoma cells (89). Tanigawa et al demonstrated the ability of quercetin treatment to upregulate ARE transcription by regulating both Nrf2 and Keap1 in HepG2 cells (85).…”

“…Schadich et al was able to demonstrate that quercetin administration in human BJ foreskin fibroblasts and aneuploid immortalized skin HaCaT keratinocytes led to significant upregulation of Nrf2 activity, as determined by a luciferase reporter assay (87). Nrf2 activity was increased in both cell lines treated with either 40 μg/mL of ginger extract or 30 μM of quercetin for 10 h. Western blot analysis showed increased levels of glutathione- S -transferase P1 (GSTP1) protein, a downstream target of Nrf2 activity, in BJ fibroblasts but not in HaCaT keratinocytes.…”

“…Nrf2 activity was increased in both cell lines treated with either 40 μg/mL of ginger extract or 30 μM of quercetin for 10 h. Western blot analysis showed increased levels of glutathione- S -transferase P1 (GSTP1) protein, a downstream target of Nrf2 activity, in BJ fibroblasts but not in HaCaT keratinocytes. It was suggested that the refractory response to upregulation of GSTP1 protein in HaCaT by activated Nrf2 is likely due to constitutively high expression in these types of cells, indicating a potentially distinct role of GSTP1 in HaCaT keratinocytes compared to normal cells (87). In immortalized rat DI TNC1 astrocytes, a range of quercetin concentrations (2.5–10 μM) attenuated lipopolysaccharide (LPS)-induced NF-κB activity and upregulated Nrf2 activity in both the presence and absence of LPS (88).…”