Paeoniflorin protects human EA.hy926 endothelial cells against gamma-radiation induced oxidative injury by activating the NF-E2-related factor 2/heme oxygenase-1 pathway

Cyanidin-3-glucoside attenuates angiotensin II-induced oxidative stress and inflammation in vascular endothelial cells

Angiotensin II (Ang II) causes oxidative stress and vascular inflammation, leading to vascular endothelial cell dysfunction, and is associated with the development of inflammatory cardiovascular diseases such as atherosclerosis. Therefore, interventions of oxidative stress and inflammation may contribute to the reduction of cardiovascular diseases. Cyanidin-3-glucoside (C3G) plays a role in the prevention of oxidative damage in several diseases. Here, we investigated the effect of C3G on Ang II-induced oxidative stress and vascular inflammation in human endothelial cells (EA.hy926). C3G dose-dependently suppressed the free radicals and inhibited the nuclear factor-kappa B (NF-κB) signaling pathway by protecting the degradation of inhibitor of kappa B-alpha (IκB-α), inhibiting the expression and translocation of NF-κB into the nucleus through the down-regulation of NF-κB p65 and reducing the expression of inducible nitric oxide synthase (iNOS). Pretreatment with C3G not only prohibited the NF-κB signaling pathway but also promoted the activity of the nuclear erythroid-related factor 2 (Nrf2) signaling pathway through the upregulation of endogenous antioxidant enzymes. Particularly, we observed that C3G significantly enhanced the production of superoxide dismutase (SOD) and induced the expression of heme oxygenase (HO-1). Our findings confirm that C3G can protect against vascular endothelial cell inflammation induced by AngII. C3G may represent a promising dietary supplement for the prevention of inflammation, thereby decreasing the risk for the development of atherosclerosis.

N-acetyl cysteine inhibits H2O2-mediated reduction in the mineralization of MC3T3-E1 cells by down-regulating Nrf2/HO-1 pathway

There are controversial findings regarding the roles of nuclear factor (erythroid-derived 2)-like 2 (Nrf2)/heme oxygenase-1 (HO-1) pathway on bone metabolism under oxidative stress. We investigated how Nrf2/HO-1 pathway affects osteoblast differentiation of MC3T3-E1 cells in response to hydrogen peroxide (H₂O₂), N-acetyl cysteine (NAC), or both. Exposing the cells to H₂O₂ decreased the alkaline phosphatase activity, calcium accumulation, and expression of osteoblast markers, such as osteocalcin and runt-related transcription factor-2. In contrast, H₂O₂ treatment increased the expression of Nrf2 and HO-1 in the cells. Treatment with hemin, a chemical HO-1 inducer, mimicked the inhibitory effect of H₂O₂ on osteoblast differentiation by increasing the HO-1 expression and decreasing the osteogenic marker genes. Pretreatment with NAC restored all changes induced by H₂O₂ to near normal levels in the cells. Collectively, our findings suggest that H₂O₂-mediated activation of Nrf2/HO-1 pathway negatively regulates the osteoblast differentiation, which is inhibited by NAC. [BMB Reports 2015; 48(11): 636-641]

Paeoniflorin protects Schwann cells against high glucose induced oxidative injury by activating Nrf2/ARE pathway and inhibiting apoptosis

ETHNOPHARMACOLOGICAL RELEVANCE

Paeoniflorin (PF) is the principal bioactive component of Paeonia lactiflora Pall., which an included in Tang Luo Ning recipe, a traditional Chinese herbal medicine based on Huangqi Guizhi Wuwu decoction. PF is also widely used in Traditional Chinese Medicine for the treatment of blood-arthralgia disease including diabetic peripheral neuropathy (DPN), but its underlying molecular mechanism of neuroprotective effects is not yet well understood. Diabetic hyperglycemia induced oxidative stress in Schwann cells, an important component of the peripheral nervous system, has been proposed as a unifying mechanism for DPN. The objective of this study is to determine the effects of PF on Schwann cells oxidative stress and apoptosis induced by high glucose.

MATERIALS AND METHODS

RSC96 cells, a Schwann cell line, were treated with high glucose (150mM) and PF (1, 10 and 100μM). Subsequently, MTT assay was performed. The level of apoptosis was examined by flow cytometry and the oxidative stress was reflected by reactive oxygen species (ROS), malondialdehyde (MDA), glutathione S-transferases (GST) and glutathione peroxidase (GPX) levels. The mRNA expressions of Nuclear factor-E2-related factor 2 (Nrf2) and heme oxygenase 1 (HO-1) were detected by qRT-PCR. The levels of Kelch-like ECH-associating protein 1 (Keap1), Nrf2, HO-1, γ-glutamylcysteine synthetase (γGCS), B-cell CLL/lymphoma 2 (Bcl-2), Bax and Caspase 3 were detected by High content analysis and/or Western blot.

RESULTS

The role of PF markedly suppressed high glucose induced Schwann cells oxidative stress by decreasing ROS and MDA levels and increasing GST and GPX activity. Western blot analysis showed that PF induced nuclear translocation of Nrf2. High content analysis showed that PF promoted Nrf2 dissociation from Keap1 and upregulating the Nrf2/ antioxidant response element (ARE) pathway. Furthermore, PF reduced Schwann cells apoptosis by increasing Bcl-2 and inhibiting Bax and Caspase-3 expressions.

CONCLUSIONS

PF in the management of Schwann cells oxidative stress induced by high glucose may be associated with activation of Nrf2/ARE pathway and Bcl-2-related apoptotic pathway.

South Asian Medicinal Compounds as Modulators of Resistance to Chemotherapy and Radiotherapy

Cancer is a hyperproliferative disorder that involves transformation, dysregulation of apoptosis, proliferation, invasion, angiogenesis and metastasis. During the last 30 years, extensive research has revealed much about the biology of cancer. Chemotherapy and radiotherapy are the mainstays of cancer treatment, particularly for patients who do not respond to surgical resection. However, cancer treatment with drugs or radiation is seriously limited by chemoresistance and radioresistance. Various approaches and strategies are employed to overcome resistance to chemotherapy and radiation treatment. Many plant-derived phytochemicals have been investigated for their chemo- and radio-sensitizing properties. The peoples of South Asian countries such as India, Pakistan, Sri Lanka, Nepal, Bangladesh and Bhutan have a large number of medicinal plants from which they produce various pharmacologically potent secondary metabolites. The medicinal properties of these compounds have been extensively investigated and many of them have been found to sensitize cancer cells to chemo- and radio-therapy. This review focuses on the role of South Asian medicinal compounds in chemo- and radio-sensitizing properties in drug- and radio-resistant cancer cells. Also discussed is the role of South Asian medicinal plants in protecting normal cells from radiation, which may be useful during radiotherapy of tumors to spare surrounding normal cells.

Paeoniflorin attenuates ultraviolet B-induced apoptosis in human keratinocytes by inhibiting the ROS-p38-p53 pathway

Ultraviolet (UV) light is one of the most harmful environmental factors that contribute to skin damage. Exposure to UV induces extensive generation of reactive oxygen species (ROS), and results in photoaging and skin cancer development. One approach to protecting human skin against UV radiation is the use of antioxidants. In recent years, naturally occurring herbal compounds have gained considerable attention as protective agents for UV exposure. Paeoniflorin (PF) is a novel natural antioxidant, which is isolated from peony root (Radix Paeoniae Alba). The present study evaluated the protective effects of PF on UV‑induced skin damage in vitro, and demonstrated that the effects were mediated via the ROS‑p38‑p53 pathway. The results of the present study demonstrated that treatment with PF (25, 50, and 100 µM) significantly increased the percentage of viable keratinocytes after UV‑B exposure. In addition, cell death analysis indicated that PF treatment markedly reduced UV‑B‑radiation‑induced apoptosis in keratinocytes, which was accompanied by increased procaspase 3 expression and decreased cleaved caspase 3 expression. Treatment with PF markedly reduced the production of ROS, and inhibited the activation of p38 and p53 in human keratinocytes, thus suggesting that the ROS‑p38‑p53 pathway has a role in UV‑B‑induced skin damage. In conclusion, the present study reported that PF was able to attenuate UV‑B‑induced cell damage in human keratinocytes. Notably, these effects were shown to be mediated, at least in part, via inhibition of the ROS-p38-p53 pathway.

Paeoniflorin attenuates hepatic ischemia/reperfusion injury via anti-oxidative, anti-inflammatory and anti-apoptotic pathways

During liver surgery, hepatic blood flow needs to be blocked in order to reduce bleeding, which inevitably results in hepatic ischemia/reperfusion injury (HI/R). Paeoniflorin (PF) is the main active ingredient of the traditional Chinese herbal medicine peony, which has been shown to exert anti-oxidative and anti-apoptotic properties. In the present study, a mouse model of HI/R was generated by clamping the hepatoportal vein, hepatic artery, and hepatic duct of BALB/c mice with a vascular clamp for 30 min, followed by reperfusion for 6 h under anesthesia. Six mice in the three PF treatment groups (5, 10 and 20 mg/kg) were then injected with PF, via the tail vein. A sham group, consisting of six mice that did not undergo the procedure, and a vehicle group, consisting of 6 mice that underwent the procedure but subsequently received injections of physiological saline only, were used as controls. Liver injury was indicated by serum levels of the enzymes alanine transaminase (ALT) and aspartate transaminase (AST). The activities of oxidative stress biomarkers, including superoxide dismutase (SOD), glutathione (GSH), glutathione peroxidase (GSH-PX) and malondialdehyde (MDA), were also measured. Furthermore, the activity of caspase-3 was analyzed in hepatic tissue using a commercial kit. Treatment with PF significantly attenuated HI/R injury histologically, as compared with the vehicle group. In addition, significant reductions in the serum levels of ALT and AST were observed in the PF-treated ischemic mice. Furthermore, treatment with PF enhanced the activities of hepatic tissue SOD, GSH and GSH-PX, but decreased the MDA content. Treatment of ischemic mice with PF markedly reduced the expression levels of inflammatory mediators, including nuclear factor-κB, tumor necrosis factor-α, interleukin (IL)-6, and IL-1β, and decreased the HI/R injury-induced expression of caspase-3. The results of the present study suggest that PF attenuates the HI/R injury of mice via anti-oxidative, anti-inflammatory and anti-apoptotic activities.

Nrf2-mediated HO-1 induction contributes to antioxidant capacity of a Schisandrae Fructus ethanol extract in C2C12 myoblasts

This study was designed to confirm the protective effect of Schisandrae Fructus, which are the dried fruits of Schisandra chinensis (Turcz.) Baill, against oxidative stress-induced cellular damage and to elucidate the underlying mechanisms in C2C12 myoblasts. Preincubating C2C12 cells with a Schisandrae Fructus ethanol extract (SFEE) significantly attenuated hydrogen peroxide (H₂O₂)-induced inhibition of growth and induced scavenging activity against intracellular reactive oxygen species (ROS) induced by H₂O₂. SFEE also inhibited comet tail formation and phospho-histone γH2A.X expression, suggesting that it prevents H₂O₂-induced cellular DNA damage. Furthermore, treating C2C12 cells with SFEE significantly induced heme oxygenase-1 (HO-1) and phosphorylation of nuclear factor-erythroid 2 related factor 2 (Nrf2). However, zinc protoporphyrin IX, a potent inhibitor of HO-1 activity, significantly reversed the protective effects of SFEE against H₂O₂-induced growth inhibition and ROS generation in C2C12 cells. Additional experiments revealed that the potential of the SFEE to induce HO-1 expression and protect against H₂O₂-mediated cellular damage was abrogated by transient transfection with Nrf2-specific small interfering RNA, suggesting that the SFEE protected C2C12 cells against oxidative stress-induced injury through the Nrf2/HO-1 pathway.

Paeoniflorin inhibits proliferation and induces apoptosis of human glioma cells via microRNA-16 upregulation and matrix metalloproteinase-9 downregulation

Paeoniflorin is one of the active ingredients of the commonly used herbal medicine derived from Paeonia, which exhibits anticancer properties. MicroRNA-16 (miR-16) is upregulated in CD133(-) cells, but downregulated in CD133(+) cells from glioma tissue. Matrix metalloproteinase-9 (MMP-9) expression in glioma tissue samples is significantly higher than that in healthy brain tissue samples. Therefore, miR-16 and MMP-9 expression may be associated with glioma pathogenesis. In the present study, the effects of paeoniflorin on glioma were analyzed. U87 cells were treated with paeoniflorin at 0, 5, 10 and 20 μΜ concentrations. The results suggested that paeoniflorin inhibited U87 cell proliferation and accelerated cell apoptosis. In the present study paeoniflorin treatment increased miR-16 expression and reduced MMP-9 protein expression in U87 cells. Additionally, the results of the present study suggested that miR-16 may regulate MMP-9 expression in miR-16-transfected U87 cells. Furthermore, anti-miR-16 antibodies were used in order to investigate the apoptotic effects of paeoniflorin on U87 cells. The results demonstrated that paeoniflorin inhibits proliferation and induces apoptosis of human glial cells, via miR-16 upregulation and MMP-9 downregulation.

Sargassum horneri methanol extract rescues C2C12 murine skeletal muscle cells from oxidative stress-induced cytotoxicity through Nrf2-mediated upregulation of heme oxygenase-1

BACKGROUND

Sargassum horneri, an edible marine brown alga, is typically distributed along the coastal seas of Korea and Japan. Although several studies have demonstrated the anti-oxidative activity of this alga, the regulatory mechanisms have not yet been defined. The aim of the present study was to examine the cytoprotective effects of S. horneri against oxidative stress-induced cell damage in C2C12 myoblasts.

METHODS

We demonstrated the anti-oxidative effects of a methanol extract of S. horneri (SHME) in a hydrogen peroxide (H2O2)-stimulated C2C12 myoblast model. Cytotoxicity was determined using the 3-(4,5-dimetylthiazol-2-yl)-2,5-diphenyl-tetrazolium assay and mode of cell death by cell cycle analysis. DNA damage was measured using a comet assay and expression of phospho-histone γH2A.X (p-γH2A.X). Levels of cellular oxidative stress as reactive oxygen species (ROS) accumulation were measured using 2',7'-dichlorofluorescein diacetate. The involvement of selected genes in the oxidative stress-mediated signaling pathway was explored using Western blot analysis.

RESULTS

SHME attenuated H2O2-induced growth inhibition and exhibited scavenging activity against intracellular ROS that were induced by H2O2. The SHME also inhibited comet tail formation, p-γH2A.X expression, and the number of sub-G1 hypodiploid cells, suggesting that it prevents H2O2-induced cellular DNA damage and apoptotic cell death. Furthermore, the SHME significantly enhanced the expression of heme oxygenase-1 (HO-1) associated with induction of nuclear factor-erythroid 2 related factor 2 (Nrf2) in a time- and concentration-dependent manner. Moreover, the protective effect of the SHME on H2O2-induced C2C12 cell damage was significantly abolished by zinc protoporphyrin IX, a HO-1 competitive inhibitor, in C2C12 cells.

CONCLUSIONS

These findings suggest that the SHME augments cellular antioxidant defense capacity through both intrinsic free radical scavenging activity and activation of the Nrf2/HO-1 pathway, protecting C2C12 cells from H2O2-induced oxidative cytotoxicity.

Bazhen decoction protects against acetaminophen induced acute liver injury by inhibiting oxidative stress, inflammation and apoptosis in mice

Bazhen decoction is a widely used traditional Chinese medicinal decoction, but the scientific validation of its therapeutic potential is lacking. The objective of this study was to investigate corresponding anti-oxidative, anti-inflammatory and anti-apoptosis activities of Bazhen decoction, using acetaminophen-treated mice as a model system. A total of 48 mice were divided into four groups. Group I, negative control, treated with vehicle only. Group II, fed with 500 mg/kg/day Bazhen decoction for 10 continuous days. Group III, received a single dose of 900 mg/kg acetaminophen. Group IV, fed with 500 mg/kg/day Bazhen decoction for 10 continuous days and a single dose of 900 mg/kg acetaminophen 30 min before last Bazhen decoction administration. Bazhen decoction administration significantly decrease acetaminophen-induced serum ALT, AST, ALP, LDH, TNF-α, IL-1β, ROS, TBARS and protein carbonyl group levels, as well as GSH depletion and loss of MMP. Bazhen decoction restore SOD, CAT, GR and GPx activities and depress the expression of pro-inflammatory factors, such as iNOS, COX-2, TNF-α, NF-κB, IL-1β and IL-6, respectively. Moreover, Bazhen decoction down-regulate acetaminophen-induced Bax/Bcl-2 ratio, caspase 3, caspase 8 and caspase 9. These results suggest the anti-oxidative, anti-inflammatory and anti-apoptosis properties of Bazhen decoction towards acetaminophen-induced liver injury in mice.