RESUMEN
We previously showed that barley sprout extract (BSE) prevents chronic alcohol intake-induced liver injury in mice. BSE notably inhibited glutathione (GSH) depletion and increased inflammatory responses, revealing its mechanism of preventing alcohol-induced liver injury. In the present study we investigated whether the antioxidant effect of BSE involves enhancing nuclear factor-erythroid 2 related factor 2 (Nrf2) activity and GSH synthesis to inhibit alcohol-induced oxidative liver injury. Mice fed alcohol for four weeks exhibited significantly increased oxidative stress, evidenced by increased malondialdehyde (MDA) level and 4-hydroxynonenal (4-HNE) immunostaining in the liver, whereas treatment with BSE (100 mg/kg) prevented these effects. Similarly, exposure to BSE (0.1-1 mg/mL) significantly reduced oxidative cell death induced by t-butyl hydroperoxide (t-BHP, 300 µM) and stabilized the mitochondrial membrane potential (∆ψ). BSE dose-dependently increased the activity of Nrf2, a potential transcriptional regulator of antioxidant genes, in HepG2 cells. Therefore, increased expression of its target genes, heme oxygenase-1 (HO-1), NADPH quinone oxidoreductase 1 (NQO1), and glutamate-cysteine ligase catalytic subunit (GCLC) was observed. Since GCLC is involved in the rate-limiting step of GSH synthesis, BSE increased the GSH level and decreased both cysteine dioxygenase (CDO) expression and taurine level. Because cysteine is a substrate for both taurine and GSH synthesis, a decrease in CDO expression would further contribute to increased cysteine availability for GSH synthesis. In conclusion, BSE protected the liver cells from oxidative stress by activating Nrf2 and increasing GSH synthesis.
Asunto(s)
Regulación de la Expresión Génica/efectos de los fármacos , Glutatión/biosíntesis , Hordeum/química , Subunidad p45 del Factor de Transcripción NF-E2/metabolismo , Extractos Vegetales/farmacología , Animales , Proteína con Homeodominio Antennapedia/farmacología , Supervivencia Celular , Enfermedad Hepática Inducida por Sustancias y Drogas/prevención & control , Proteínas de Drosophila/farmacología , Etanol/toxicidad , Células Hep G2 , Humanos , Peroxidación de Lípido , Masculino , Ratones , Subunidad p45 del Factor de Transcripción NF-E2/genética , Extractos Vegetales/química , Especies Reactivas de OxígenoRESUMEN
The effect of commercially available green tea (GT) and black tea (BT) drinks on drug metabolizing enzymes (DME) and oxidative stress in rats was investigated. Male Wistar rats were fed a laboratory chow diet and GT or BT drink for 5 weeks. Control rats received de-ionized water instead of the tea drinks. Rats received the GT and BT drinks treatment for 5 weeks showed a significant increase in hepatic microsomal cytochrome P450 (CYP) 1A1 and CYP1A2, and a significant decrease in CYP2C, CYP2E1 and CYP3A enzyme activities. Results of immunoblot analyses of enzyme protein contents showed the same trend with enzyme activity. Significant increase in UDP-glucuronosyltransferase activity and reduced glutathione content in liver and lungs were observed in rats treated with both tea drinks. A lower lipid peroxide level in lungs was observed in rats treated with GT drink. Electrophoretic mobility shift assay revealed that both tea drinks decreased pregnane X receptor binding to DNA and increased nuclear factor-erythroid 2 p45-related factor 2 binding to DNA. These results suggest that feeding of both tea drinks to rats modulated DME activities and reduced oxidative stress in liver and lungs. GT drink is more effective on reducing oxidative stress than BT drink.
Asunto(s)
Camellia sinensis/química , Estrés Oxidativo , Té/química , Animales , Antioxidantes/farmacología , Cafeína/sangre , Colesterol/metabolismo , Citocromo P-450 CYP1A1/genética , Citocromo P-450 CYP1A1/metabolismo , Citocromo P-450 CYP1A2 , Citocromo P-450 CYP2E1/genética , Citocromo P-450 CYP2E1/metabolismo , Citocromo P-450 CYP3A/genética , Citocromo P-450 CYP3A/metabolismo , Sistema Enzimático del Citocromo P-450/genética , Sistema Enzimático del Citocromo P-450/metabolismo , Citocromos/genética , Citocromos/metabolismo , Glutatión/metabolismo , Hígado/metabolismo , Pulmón/metabolismo , Masculino , Subunidad p45 del Factor de Transcripción NF-E2/genética , Subunidad p45 del Factor de Transcripción NF-E2/metabolismo , Receptor X de Pregnano , Ratas , Ratas Wistar , Receptores de Esteroides/genética , Receptores de Esteroides/metabolismo , Triglicéridos/metabolismoRESUMEN
Cells and tissues counteract insults from exogenous or endogenous carcinogens through the expression of genes encoding antioxidants and phase II detoxifying enzymes regulated by antioxidant response element promoter regions. Nuclear factor-erythroid 2-related factor 2 plays a key role in regulating the antioxidant response elements-target gene expression. Hence, the Nrf2/ARE pathway represents a vital cellular defense mechanism against damage caused by oxidative stress and xenobiotics, and is recognized as a potential molecular target for discovering chemopreventive agents. Using a stable antioxidant response element luciferase reporter cell line derived from human breast cancer MDA-MB-231 cells combined with a 96-well high-throughput screening system, we have identified a series of plant extracts from the family Lauraceae that harbor Nrf2-inducing effects. These extracts, including Litsea garrettii (ZK-08), Cinnamomum chartophyllum (ZK-02), C. mollifolium (ZK-04), C. camphora var. linaloolifera (ZK-05), and C. burmannii (ZK-10), promoted nuclear translocation of Nrf2, enhanced protein expression of Nrf2 and its target genes, and augmented intracellular glutathione levels. Cytoprotective activity of these extracts against two electrophilic toxicants, sodium arsenite and H2O2, was investigated. Treatment of human bronchial epithelial cells with extracts of ZK-02, ZK-05, and ZK-10 significantly improved cell survival in response to sodium arsenite and H2O2, while ZK-08 showed a protective effect against only H2O2. Importantly, their protective effects against insults from both sodium arsenite and H2O2 were Nrf2-dependent. Therefore, our data provide evidence that the selected plants from the family Lauraceae are potential sources for chemopreventive agents targeting the Nrf2/ARE pathway.
Asunto(s)
Anticarcinógenos/química , Antioxidantes/metabolismo , Lauraceae/química , Subunidad p45 del Factor de Transcripción NF-E2/metabolismo , Extractos Vegetales/química , Anticarcinógenos/aislamiento & purificación , Línea Celular Tumoral , Ensayos de Selección de Medicamentos Antitumorales , Humanos , Extractos Vegetales/farmacologíaRESUMEN
OBJECTIVE: To explore the mechanism of acupuncture for delaying aging. METHODS: Using the senescence accelerated mouse pattern SAMP10 and the normal aging mice SAMR1 as models and applying RT-PCR and digoxin (DIG)-labeled Northern blot technique to observe expressions of NF-E2, YB-1, LRG47 genes in the forebrain, cortex and hippocampus in a 8-month old SAMR1 control group, a 8-month old SAMP10 control group, a 8-month old SAMP10 acupuncture group and a 8-month old SAMP10 non-point stimulation group. RESULTS: In the SAMP10 control group, the expressions of NF-E2, YB-1 and LRG47 were down-regulated in the forebrain, cortex and hippocampus, and after acupuncture they were up-regulated and tended to normal. CONCLUSION: The brain aging of the SAMP10 mice is related with abnormal expressions of NF-E2, YB-1 and LRG47 genes; and acupuncture can regulate the expressions of NF-E2, YB-1 and LRG47 genes, strengthening the functions of erythrocyte series, increasing the proliferation of cells and enhancing the cellular immune function in anti-bacteria, hence delaying aging.
Asunto(s)
Terapia por Acupuntura , Envejecimiento/genética , Proteínas de Unión al GTP/genética , Expresión Génica , Subunidad p45 del Factor de Transcripción NF-E2/genética , Factores de Transcripción/genética , Envejecimiento/metabolismo , Animales , Femenino , Proteínas de Unión al GTP/metabolismo , Humanos , Masculino , Ratones , Ratones Transgénicos , Modelos Animales , Subunidad p45 del Factor de Transcripción NF-E2/metabolismo , Distribución Aleatoria , Factores de Transcripción/metabolismoRESUMEN
In rat liver, in addition to their intrinsic transferase activity, alpha-class GSTs have Se-independent glutathione peroxidase activity toward fatty acid hydroperoxides, cumene hydroperoxide and phospholipids hydroperoxides but not toward H(2)O(2.) We have previously shown that hepatic GST activity by these isoenzymes is significantly increased 24h after cadmium or manganese administration (Casalino et al., 2004). Here it is reported that Se-independent glutathione peroxidase activity by alpha-class GSTs is also stimulated in the liver of intoxicated rats. The stimulation is associated with a higher level of alpha-class GST proteins, whose induction is blocked by actinomycin D co-administration. The observed Se-independent glutathione peroxidase activity is due to alpha-class GST isoenzymes, as indicated by the studies with diethyldithiocarbamate which, at any concentration, equally inhibits both GST and Se-independent glutathione peroxidase and is an uncompetitive inhibitor of both enzymes. As for liver Se-GSPx, it is not at all affected under these toxic conditions. For comparison, we have evaluated the status of another important antioxidant enzyme, NAD(P)H:quinone reductase, 24h after cadmium or manganese administration. NQO1 too results strongly stimulated in the liver of the intoxicated rats. In these animals, a higher expression of Nrf2 protein is observed, actively translocated from the cytoplasm to the nucleus. The results with the transcription inhibitor, actinomycin D, and the effects on Nrf2 protein are the first clear indication that acute manganese intoxication, similarly to that of cadmium and other heavy metals, increases both the hepatic level of Nrf2 and its transfer from the cytoplasm to the nucleus where it actively regulates the induction of phase II enzymes.