Expression Of Antioxidant Defense Genes Research Articles

The Slow Progression of Diabetic Retinopathy Is Associated with Transient Protection of Retinal Vessels from Death.

The purpose of this study was to investigate the reason that diabetic retinopathy (DR) is delayed from the onset of diabetes (DM) in diabetic mice. To this end, we tested the hypothesis that the deleterious effects of DM are initially tolerated because endogenous antioxidative defense is elevated and thereby confers resistance to oxidative stress-induced death. We found that this was indeed the case in both type 1 DM (T1D) and type 2 DM (T2D) mouse models. The retinal expression of antioxidant defense genes was increased soon after the onset of DM. In addition, ischemia/oxidative stress caused less death in the retinal vasculature of DM versus non-DM mice. Further investigation with T1D mice revealed that protection was transient; it waned as the duration of DM was prolonged. Finally, a loss of protection was associated with the manifestation of both neural and vascular abnormalities that are diagnostic of DR in mice. These observations demonstrate that DM can transiently activate protection from oxidative stress, which is a plausible explanation for the delay in the development of DR from the onset of DM.

Deciphering the Role of the Anaphylatoxin C3a: A Key Function in Modulating the Tumor Microenvironment.

The complement system plays a crucial role in cancer development. Our study investigated the role of C3a anaphylatoxin on the tumor microenvironment. Our models consisted of mesenchymal stem cells (MSC-like, 3T3-L1), macrophages (Raw 264.7 Blue, (RB)) and tumor cells (melanoma B16/F0). Recombinant mouse (Mo) C3a (rC3a) was produced in CHO cells transfected with a Mo-IL10-signal peptide-Mo C3a plasmid construct. The effects of rC3a, IFN-γ, TGF-β1, and LPS were tested on the expression of C3, C3aR, PI3K, cytokines, chemokines, transcription factors, antioxidant defense mechanisms, angiogenesis and macrophage polarization (M1/M2). 3T3-L1 expressed the highest levels of C3, while C3aR was expressed more by RB. Interestingly, expression of C3/3T3-L1 and C3aR/RB was markedly upregulated by IFN-γ. rC3a was found to upregulate the expression of anti-inflammatory cytokines (IL-10) on 3T3-L1 and TGF-β1 on RB. rC3a also upregulated the expression of pro-inflammatory cytokines in RB. The expression of CCL-5 increased in 3T3-L1 in response to rC3a. On RB, rC3a did not alter M1/M2 polarization but upregulated the expression of antioxidant defense genes, HO-1, and VEGF. C3/C3a produced mainly by MSC may play a critical role in TME remodeling by stimulating both anti-inflammatory and proangiogenic activities of tumor stromal cells.

Neonatal kaempferol exposure attenuates impact of cerebral palsy model on neuromotor development, cell proliferation, microglia activation, and antioxidant enzyme expression in the hippocampus of rats

ABSTRACT Objectives This study aims to assess the effect of neonatal treatment with kaempferol on neuromotor development, proliferation of neural precursor cells, the microglia profile, and antioxidant enzyme gene expression in the hippocampus. Methods A rat model of cerebral palsy was established using perinatal anoxia and sensorimotor restriction of hindlimbs during infancy. Kaempferol (1 mg/ kg) was intraperitoneally administered during the neonatal period. Results Neonatal treatment with kaempferol reduces the impact of the cerebral palsy model on reflex ontogeny and on the maturation of physical features. Impairment of locomotor activity development and motor coordination was found to be attenuated by kaempferol treatment during the neonatal period in rats exposed to cerebral palsy. Neonatal treatment of kaempferol in cerebral palsy rats prevents a substantial reduction in the number of neural precursor cells in the dentate gyrus of the hippocampus, an activated microglia profile, and increased proliferation of microglia in the sub-granular zone and in the granular cell layer. Neonatal treatment with kaempferol increases gene expression of superoxide dismutase and catalase in the hippocampus of rats submitted to the cerebral palsy model. Discussion Kaempferol attenuates the impact of cerebral palsy on neuromotor behavior development, preventing altered hippocampal microglia activation and mitigating impaired cell proliferation in a neurogenic niche in these rats. Neonatal treatment with kaempferol also increases antioxidant defense gene expression in the hippocampus of rats submitted to the cerebral palsy model.

EVALUATION OF THE GEROPROTECTIVE EFFECT OF SQUALENE ON THE CAENORHABDITIS ELEGANS MODEL

Background. Increasing healthy life expectancy is a priority in modern healthcare. Squalene, a triterpene exhibiting antioxidant, anti-inflammatory and other properties, is a promising candidate for geroprotectors.
 Purpose. Assess the activity of squalene, that is, the possibility of its further use as a geroprotector.
 Materials and methods. Squalene was purchased from Sigma-Aldrich (USA) for research. Squalene solutions were prepared with concentrations of 10, 50, 100, 200, 400, 800, and 1600 µmol/L (solvent dimethyl sulfoxide—DMSO). The work was carried out on the basis of the Laboratory for Biotesting of Natural Nutraceuticals (KemGU, Russia). Antioxidant activity was assessed by capturing ABTS radical cations in comparison with the activity of ascorbic acid. The model organism Caenorhabditis elegans N2 Bristol was purchased from the Laboratory for the Development of Innovative Medicines and Agrobiotechnologies of the Moscow Institute of Physics and Technology. To assess the stress resistance of nematodes during cultivation, conditions of thermal (33°C) and oxidative (adding 15 μl of 1 M paraquat, 20°C) stress were created for 24 and 48 h. conditions (20 °C) for 61 days. The statistical significance of the results was assessed using Student’s t-test (in Microsoft Office Excel 2007). Lifespan data were assessed using a Kaplan-Meier survival plot combined with a log-rank test (Mantel-Cox). Data processing was carried out using the OASIS online application (https://sbi.postech.ac.kr/oasis/).
 Results. The results showed that squalene solutions did not exhibit antioxidant properties; did not trap radical cations with ABTS. A solution of squalene at a concentration of 10 μM contributed to an increase in the stress resistance of nematodes. Under conditions of oxidative stress, the survival of nematodes during cultivation for 24 hours is 3.1% higher than in the control. Under conditions of heat stress during cultivation for 48 hours, the survival rate is higher by 11.3%. Squalene solutions did not affect the lifespan of nematodes.
 Conclusion. Presumably, the antioxidant activity of squalene is expressed not in the capture of free radicals, but in the ability to act on biomolecules that lead to oxidative stress. A squalene solution with a concentration of 10 μM can reduce the negative impact of one of the factors causing premature aging. In order to assess the possibility of using squalene as a geroprotector without relying on cation-radical capture, further studies are needed to study the impact of the substance on other targets, mechanisms of action related to the occurrence of age-associated diseases. For example, analysis of the effect of squalene solutions on the growth rate of C. elegans larvae, the ability to influence the expression of antioxidant defense genes, the presence of anti-inflammatory and other properties.

Long‐term Administration of Resveratrol and MitoQ Stimulates Antioxidant Gene Expression in a Mice Castration Model of Erectile Dysfunction

Erectile Dysfunction (ED) is the most common sexual dysfunction in men and is characterized by the inability to achieve or maintain an erection satisfactory for sexual intercourse. Normal erectile function is highly dependent on testosterone so any dysfunction in testosterone production may accelerate ED pathogenesis. Hypogonadism is a direct cause of ED and is characterized by the diminishing functionality of the testes in producing testosterone. Other pathological conditions such as obesity and diabetes, share similar complications of ED due to decreased testosterone levels. Furthermore, these conditions exhibit increased oxidative stress. Decreased testosterone can weaken antioxidant defenses and increase oxidative stress that then leads to endothelial dysfunction by reducing nitric oxide bioavailability and increasing fibrosis which ultimately leads to ED. Current therapies for ED do not directly target antioxidant defenses to reduce oxidative stress damage. Two prospective drugs, Resveratrol and Mitoquinone (MitoQ), have antioxidant properties that limit oxidative stress and may improve erectile function. They have shown to be successful in decreasing oxidative stress damage and improving endothelial function in cardiovascular disease models, so the objective of this study was to explore the effect resveratrol and MitoQ has on antioxidant defense gene expression and erectile function in a model of hypogonadism. We hypothesized that resveratrol and MitoQ treatment will improve antioxidant defenses and improve erectile function. In this study, we used a surgically castrated mouse model to induce ED. We treated mice with resveratrol or MitoQ for eight weeks. Following treatment, we sacrificed and harvested mice corpus cavernosum (CC). We measured the expression of genes related to antioxidant defenses by performing qRT‐PCR. Additionally, ex vivo vasoreactivity of the internal pudendal artery (IPA) and CC were assessed in response to concentration ranges of multiple agonists with DMT myograph system. One‐way ANOVA and Two‐way ANOVA, respectively, was used to compare differences between groups. Upon castration, vasorelaxation of the IPA and CC significantly declined. Antioxidant defenses were reduced with castration as seen by reduced expression in: Gclc, Gpx1, Prdx3, Prdx5, Nqo1, SOD2, SOD3, and Hmox1. After treatment, vasorelaxation did not improve however there were improvements in antioxidant gene expression. Resveratrol significantly increased expression of Gstm, CAT, SOD1. Additionally, MitoQ and resveratrol trended to increase several antioxidant genes. There was a partially restoration of Gpx1, Prdx3, Nqo1 and SOD2 levels and Hmox1 was restored back to sham levels. To conclude, neither long‐term administration of MitoQ nor resveratrol improved relaxation responses of the IPA or CC, however, they were able to stimulate and improve antioxidant gene expression. Even though these drugs were unable to improve erectile function on their own, they may be paired with other treatments such as PDE‐5 inhibitors, to make them more effective in more severe case of ED. Future research should explore co‐treatment in a castrated model of ED.

Effects of benzo[a]pyrene exposure on oxidative stress and apoptosis of gill cells of Chlamys farreri in vitro

As a common pollutant in marine environment, benzo[a]pyrene (B[a]P) has high toxicity to economic shellfish. In order to explore the mechanism of oxidative stress and apoptosis, the effects of 0, 2, 4, 8 μg/mL B[a]P on gill cells of C. farreri at 12 and 24 h were studied. The results showed that B[a]P decreased the activity of gill cells, increased the content of reactive oxygen species (ROS) and the expression of antioxidant defense genes. Besides, B[a]P could induce oxidative damage to nucleus and mitochondria. The gene expression and enzyme activity of apoptosis pathway related factors were changed. In conclusion, these results showed that B[a]P could cause oxidative stress and oxidative damage in gill cells of C. farreri, and mediate gill cell apoptosis through mitochondrial pathway and death receptor pathway. This article provides a theoretical basis for clarifying the molecular mechanism of PAHs-included oxidative stress and apoptosis in bivalves.

Caffeic acid and resveratrol ameliorate cellular damage in cell and Drosophila models of spinocerebellar ataxia type 3 through upregulation of Nrf2 pathway.

Polyglutamine (polyQ)-expanded mutant ataxin-3 protein, which is prone to misfolding and aggregation, leads to cerebellar neurotoxicity in spinocerebellar ataxia type 3 (SCA3), an inherited PolyQ neurodegenerative disease. Although the exact mechanism is unknown, the pathogenic effects of mutant ataxin-3 are associated with dysregulation of transcription, protein degradation, mitochondrial function, apoptosis, and antioxidant potency. In the present study we explored the protective role and possible mechanism of caffeic acid (CA) and resveratrol (Res) in cells and Drosophila expressing mutant ataxin-3. Treatment with CA and Res increased the levels of antioxidant and autophagy protein expression with consequently corrected levels of reactive oxygen species, mitochondrial membrane potential, mutant ataxin-3, and the aggregation of mutant ataxin-3 in SK-N-SH-MJD78 cells. Moreover, in SK-N-SH-MJD78 cells, CA and Res enhanced the transcriptional activity of nuclear factor erythroid-derived-2-like 2 (Nrf2), a master transcription factor that upregulates the expression of antioxidant defense genes and the autophagy gene p62. CA and Res improved survival and motor performance in SCA3 Drosophila. Additionally, the above-mentioned protective effects of CA were also observed in CA-supplemented SCA3 Drosophila. Notably, blockade of the Nrf2 pathway by use of small interfering RNA annulled the health effects of CA and Res on SCA3, which affirmed the importance of the increase in Nrf2 activation by CA and Res. Additional studies are need to dissect the protective role of CA and Res in modulating neurodegenerative progression in SCA3 and other polyQ diseases.

Comprehensive analysis of gene expression patterns in Friedreich's ataxia fibroblasts by RNA sequencing reveals altered levels of protein synthesis factors and solute carriers.

ABSTRACTFriedreich's ataxia (FRDA) is an autosomal recessive neurodegenerative disease usually caused by large homozygous expansions of GAA repeat sequences in intron 1 of the frataxin (FXN) gene. FRDA patients homozygous for GAA expansions have low FXN mRNA and protein levels when compared with heterozygous carriers or healthy controls. Frataxin is a mitochondrial protein involved in iron–sulfur cluster synthesis, and many FRDA phenotypes result from deficiencies in cellular metabolism due to lowered expression of FXN. Presently, there is no effective treatment for FRDA, and biomarkers to measure therapeutic trial outcomes and/or to gauge disease progression are lacking. Peripheral tissues, including blood cells, buccal cells and skin fibroblasts, can readily be isolated from FRDA patients and used to define molecular hallmarks of disease pathogenesis. For instance, FXN mRNA and protein levels as well as FXN GAA-repeat tract lengths are routinely determined using all of these cell types. However, because these tissues are not directly involved in disease pathogenesis, their relevance as models of the molecular aspects of the disease is yet to be decided. Herein, we conducted unbiased RNA sequencing to profile the transcriptomes of fibroblast cell lines derived from 18 FRDA patients and 17 unaffected control individuals. Bioinformatic analyses revealed significantly upregulated expression of genes encoding plasma membrane solute carrier proteins in FRDA fibroblasts. Conversely, the expression of genes encoding accessory factors and enzymes involved in cytoplasmic and mitochondrial protein synthesis was consistently decreased in FRDA fibroblasts. Finally, comparison of genes differentially expressed in FRDA fibroblasts to three previously published gene expression signatures defined for FRDA blood cells showed substantial overlap between the independent datasets, including correspondingly deficient expression of antioxidant defense genes. Together, these results indicate that gene expression profiling of cells derived from peripheral tissues can, in fact, consistently reveal novel molecular pathways of the disease. When performed on statistically meaningful sample group sizes, unbiased global profiling analyses utilizing peripheral tissues are critical for the discovery and validation of FRDA disease biomarkers.

Chronic Endurance Exercise Impairs Cardiac Structure and Function in Middle-Aged Mice with Impaired Nrf2 Signaling.

Nuclear factor erythroid 2 related factor 2 (Nrf2) signaling maintains the redox homeostasis and its activation is shown to suppress cardiac maladaptation. Earlier we reported that acute endurance exercise (2 days) evoked antioxidant cytoprotection in young WT animals but not in aged WT animals. However, the effect of repeated endurance exercise during biologic aging (WT) characterized by an inherent deterioration in Nrf2 signaling and pathological aging (pronounced oxidative susceptibility—Nrf2 absence) in the myocardium remains elusive. Thus, the purpose of our study was to determine the effect of chronic endurance exercise-induced cardiac adaptation in aged mice with and without Nrf2. Age-matched WT and Nrf2-null mice (Nrf2−/−) (>22 months) were subjected to 6 weeks chronic endurance exercise (25 meter/min, 12% grade). The myocardial redox status was assessed by expression of antioxidant defense genes and proteins along with immunochemical detection of DMPO-radical adduct, GSH-NEM, and total ubiquitination. Cardiac functions were assessed by echocardiography and electrocardiogram. At sedentary state, loss of Nrf2 resulted in significant downregulation of antioxidant gene expression (Nqo1, Ho1, Gclm, Cat, and Gst-α) with decreased GSH-NEM immuno-fluorescence signals. While Nrf2−/− mice subjected to CEE showed an either similar or more pronounced reduction in the transcript levels of Gclc, Nqo1, Gsr, and Gst-α in relation to WT littermates. In addition, the hearts of Nrf2−/− on CEE showed a substantial reduction in specific antioxidant proteins, G6PD and CAT along with decreased GSH, a pronounced increase in DMPO-adduct and the total ubiquitination levels. Further, CEE resulted in a significant upregulation of hypertrophy genes (Anf, Bnf, and β-Mhc) (p < 0.05) in the Nrf2−/− hearts in relation to WT mice. Moreover, the aged Nrf2−/− mice exhibited a higher degree of cardiac remodeling in association with a significant decrease in fractional shortening, pronounced ST segment, and J wave elevation upon CEE compared to age-matched WT littermates. In conclusion, our findings indicate that while the aged WT and Nrf2 knockout animals both exhibit hypertrophy after CEE, the older Nrf2 knockouts showed ventricular remodeling coupled with profound cardiac functional abnormalities and diastolic dysfunction.

The Role of Oxidative Stress and Hypoxia in Pancreatic Beta-Cell Dysfunction in Diabetes Mellitus.

Metabolic syndrome is a frequent precursor of type 2 diabetes mellitus (T2D), a disease that currently affects ∼8% of the adult population worldwide. Pancreatic beta-cell dysfunction and loss are central to the disease process, although understanding of the underlying molecular mechanisms is still fragmentary. Recent Advances: Oversupply of nutrients, including glucose and fatty acids, and the subsequent overstimulation of beta cells, are believed to be an important contributor to insulin secretory failure in T2D. Hypoxia has also recently been implicated in beta-cell damage. Accumulating evidence points to a role for oxidative stress in both processes. Although the production of reactive oxygen species (ROS) results from enhanced mitochondrial respiration during stimulation with glucose and other fuels, the expression of antioxidant defense genes is unusually low (or disallowed) in beta cells. Not all subjects with metabolic syndrome and hyperglycemia go on to develop full-blown diabetes, implying an important role in disease risk for gene-environment interactions. Possession of common risk alleles at the SLC30A8 locus, encoding the beta-cell granule zinc transporter ZnT8, may affect cytosolic Zn2+ concentrations and thus susceptibility to hypoxia and oxidative stress. Loss of normal beta-cell function, rather than total mass, is increasingly considered to be the major driver for impaired insulin secretion in diabetes. Better understanding of the role of oxidative changes, its modulation by genes involved in disease risk, and effects on beta-cell identity may facilitate the development of new therapeutic strategies to this disease. Antioxid. Redox Signal. 26, 501-518.

Protección celular antioxidante y respuesta adaptativa inducida por estímulos oxidativos crónicos

Adaptation is an important mechanism in cells and organisms that allow them to respond to environmental challenges and changing functional demands. To accomplish these requirements, cells integrate modifications at different levels such as gene expression, metabolic activity, cellular functionality and phenotype. The orderly coordination of these changes is fundamental for cells to maintain viability despite a variety of harmful stimuli, such as the case of exceedingly concentrations of reactive oxygen species (ROS). In this study, we tested the hypothesis that chronic and repetitive stimuli with a mild concentration of hydrogen peroxide (H2O2) would activate cellular responses, resulting in adaptation. This was done confronting cell cultures to prolonged exposures of H2O2 obtained with glucose oxydase (GlucOx) added to the medium to generate a constant concentration of the oxidant (≈ 50 μM); this treatment protocol (1h/d) was extended during seven continuous consecutive days after which the following parameters were evaluated: cell morphology and viability, mitochondrial DNA content, mitochondrial ROS accumulation and antioxidant defense gene expression. These data further support the idea that exposure to continuous and low concentrations of ROS, could act as signaling molecules inducing cellular processes that converged toward adaptation to chronic oxidative stress.

A Maternal High-Fat Diet Represses the Expression of Antioxidant Defense Genes and Induces the Cellular Senescence Pathway in the Liver of Male Offspring Rats

Maternal high-fat (HF) diet feeding is associated with increased risk of developing metabolism-related diseases in adult offspring, including chronic liver disease. The present study tested the hypothesis that maternal HF diet leads to a decreased antioxidant defense capacity and causes cellular senescence in liver of adult offspring rats, which might increase risk of developing chronic liver disease. Timed-pregnant Sprague Dawley rats were fed a HF diet (45% of energy from fat) or a control (C) diet (16% of energy from fat) during gestation and lactation. The resulting offspring were fed a C diet after weaning to generate 2 offspring groups: C diet-fed offspring of dams fed C diet (C/C) and C diet-fed offspring of dams fed a HF diet (HF/C). At 12 wk of age, male rats were killed and samples were collected for analysis. Maternal HF diet significantly increased plasma TG and hepatic TBARS concentrations and the size of hepatic lipid droplets in offspring rats. The expression of antioxidant defense genes, such as glutathione peroxidase-1, Cu/Zn superoxide dismutase (Sod1), paraoxonase enzymes (Pon1Pon2, andPon3), were significantly lower in the liver of HF/C pups than in C/C pups. The expression of Inhibitor of cyclin dependent Kinase 4a (p16INK4a), a marker of cellular senescence, and cyclooxygenase-2 (Cox2), a proinflammatory marker, was significantly higher in the HF/C offspring group than in the C/C offspring group. Western-blot analysis shows that cyclin D1 and phosphorylated retinoblastoma protein were significantly lower in HF/C offspring than in C/C offspring. The results provide the first evidence to our knowledge that maternal HF diet might alter antioxidant defense capacity and program the p16INK4a-dependent cellular senescence in the liver of adult offspring.

Abstract 5583: Differential effect of phenethyl isothiocyanate on expression of antioxidant defense genes between normal and cancerous human prostate cells

Abstract Phenethyl isothiocyanate (PEITC) is a promising cancer chemopreventive constituent of cruciferous vegetables (e.g., watercress) as evidenced by efficacy against chemically-induced cancer in experimental rodents. The PEITC is also empowered to inhibit growth of cultured and xenografted human prostate cancer cells, which correlates with apoptotic and autophagic cell death. We have shown previously that reactive oxygen species (ROS) play a critical role in proapoptotic signal transduction by PEITC in human prostate cancer cells. Interestingly, a representative normal human prostate epithelial cell line (PrEC) is significantly more resistant to PEITC-induced apoptosis compared with cancerous prostate cells including PC-3 and LNCaP. However, the mechanism behind this differential response remains elusive. The present study was undertaken to test a hypothesis that differential sensitivity of normal versus cancerous human prostate cells to PEITC-mediated proapoptotic response is determined by differences in ROS production and/or basal or inducible expression of antioxidant defense genes. The PEITC treatment resulted in ROS production in PC-3 human prostate cancer cells as judged by flow cytometry and fluorescence microscopy using a chemical probe (MItoSOX Red) and EPR using a cell permeable sin probe (1-hydroxy-3-methoxy-carbonyl-2,2,5,5-tetramethylpyrrolidine). These effects were not observed in PrEC cells similarly treated with the PEITC. Basal antioxidant defense gene expression signature was strikingly different between PC-3 and PrEC cells. Moreover, PEITC treatment (2.5 μM, 6 h) caused up-regulation of 29 genes and down-regulation of 2 genes in PC-3 cells. Conversely only 4 genes were up-regulated and 10 genes were down-regulated by a similar PEITC treatment in the PrEC cell line. The results of the present study clearly indicate that differential sensitivity of PC-3 versus PrEC cells to proapoptotic effect of PEITC is likely attributable to both differences in ROS production and basal as well as altered expression of antioxidant defense genes. This investigation was supported by the USPHS grant CA101753-07, awarded by the National Cancer Institute. Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr 5583. doi:10.1158/1538-7445.AM2011-5583

Expression of antioxidant defense genes in mung bean (Vigna radiata L.) roots under water-logging is associated with hypoxia tolerance

This study was conducted to examine the extent of oxidative stress and the role of antioxidant enzymes on hypoxia tolerance in highly tolerant wild species Vigna luteola, and mung bean (Vigna radiata) cvs. T 44 (tolerant) and Pusa Baisakhi (susceptible). Two days of water-logging caused about 40–50% decline in superoxide radical (O2·−) and hydrogen peroxide (H2O2) contents in all the genotypes, however, further water-logging to 8 days caused significant increase in O2·− and H2O2 contents, and the values were 80–90% of the control values. In control and revived plants O2·− and H2O2 contents were higher in Pusa Baisakhi, while under water-logging stress T 44 and V. luteola showed greater increases in the O2·− and H2O2 contents. Hypoxia induced increase in superoxide dismutase, ascorbate peroxidase, and glutathione reductase activities were higher in T 44 and V. luteola compared with Pusa Baisakhi; and the increases in T 44 and V. luteola continued up to 8th day of water-logging, while in case of Pusa Baisakhi, the maximum increase was observed only on the 2nd day of water-logging. Gene expression studies showed enhanced expression of cytosolic-Cu/Zn-superoxide dismutase (SOD) and cytosolic-ascorbate peroxidase (APX) in the roots of waterlogged V. luteola and T 44, while little expression was observed in control or treated plants of Pusa Baisakhi. PCR band products were cloned and sequenced, and partial cDNAs of Cu/Zn-SOD and APX, respectively, were obtained. Results suggest that increase in the activity of antioxidant enzymes is to scavenge reactive oxygen species produced both during and after relief from water-logging stress.

Differential Response of Normal (PrEC) and Cancerous Human Prostate Cells (PC-3) to Phenethyl Isothiocyanate-Mediated Changes in Expression of Antioxidant Defense Genes

The present study was undertaken to test a hypothesis that differential sensitivity of normal and cancerous human prostate cells to prooxidant effect of phenethyl isothiocyanate (PEITC) is determined by altered expression of antioxidant defense genes. Prooxidant effect of PEITC was assessed by flow cytometry using a chemical probe and measurement of hydrogen peroxide production. Gene expression was determined by real-time PCR using Human Oxidative Stress and Antioxidant Defense RT(2) Profiler™. Protein expression was determined by Western blotting. The PEITC treatment resulted in generation of reactive oxygen species and hydrogen peroxide production in PC-3 human prostate cancer cells but not in a representative normal human prostate epithelial cell line (PrEC). Basal oxidative stress-antioxidant defense gene expression signature was strikingly different between PC-3 and PrEC cells. The PEITC treatment (2.5μM, 6h) caused up-regulation of 29 genes and down-regulation of 2 genes in PC-3 cells. Conversely, 4 genes were up-regulated, and 10 genes were down-regulated by a similar PEITC treatment in the PrEC cell line. Differential sensitivity of PC-3 versus PrEC cells to prooxidant effect of PEITC is likely attributable to difference in basal as well as altered expression of antioxidant defense genes.

Antioxidant Defenses in the Rat Placenta in Late Gestation: Increased Labyrinthine Expression of Superoxide Dismutases, Glutathione Peroxidase 3, and Uncoupling Protein 21

Placental oxidative stress plays a key role in the pathophysiology of placenta-related disorders, most notably preeclampsia (PE) and intrauterine growth restriction (IUGR). Oxidative stress occurs when accumulation of reactive oxygen species (ROS) damages DNA, proteins and lipids, an outcome that is limited by antioxidant enzymes; mitochondrial uncoupling protein 2 (UCP2) may also limit oxidative stress by reducing ROS production. Here we characterized placental antioxidant defenses during normal gestation and following glucocorticoid-induced IUGR. Placentas were collected on Days 16 and 22 of normal rat pregnancy (term = Day 23) and at Day 22 after dexamethasone treatment from Day 13. Expression of several genes encoding antioxidant enzymes (Sod1, Sod2, Sod3, Cat, Gpx3, Txn1, Txnrd1, Txnrd2, and Txnrd3) and Ucp2 was measured by quantitative RT-PCR in the labyrinth (LZ) and junctional zones (JZ) of the placenta. Expression of Sod1 and Ucp2 mRNAs and the activity of xanthine oxidase, a source of ROS, all increased from Days 16 to 22 in both placental zones, whereas Sod2 and Gpx3 increased only in the rapidly growing LZ. In contrast, Sod3 and Txnrd1 expression fell in the LZ over this period, whereas total superoxide dismutase activity remained stable. Dexamethasone treatment reduced fetal-placental growth and LZ expression of Ucp2 but increased JZ expression of Txn1. Indices of placental oxidative damage (TBARS, F(2)-isoprostanes, and 8-OHdG) did not change with gestational age or dexamethasone, indicative of adequate antioxidant protection. Overall, our data suggest that the rat placenta is protected from oxidative stress by the dynamic zone- and stage-dependent expression of antioxidant defense genes.

Alteration in skeletal muscle antioxidant defense gene expression profile following multiple exposures to hyperthermia

Heat load is a potent stressor, due in part, to alterations in the production of reactive oxygen species (ROS). The ability of skeletal muscle to mitigate potentially harmful effects of hyperthermia and elevated ROS is unclear. Study objectives were to determine the effects of single and multiple bouts of acute heat stress (HS) on the expression of genes associated with antioxidant defense in soleus (type I; oxidative) and tibialis anterior (TA; type II; glycolytic) skeletal muscles. Male Sprague Dawley rats (n = 12; 9 mo) were randomly assigned to one of 3 treatment groups; thermoneutral (TN; 22°C) or either 1 or 2 exposures to HS conditions (40°C, 20% relative humidity, 6 h each). Rats were anesthetized and skeletal muscles were collected. Total RNA was isolated and cDNA generated for a real‐time PCR‐based array (SABiosciences). During TN, gene expression of antioxidants (catalase, glutathione peroxidases, peroxiredoxins, and superoxide dismutase 1) were greater (p &lt; 0.05) in the soleus compared to TA. After one bout of heat, the difference in antioxidant gene expression observed during TN increased (p &lt; 0.05) further between the soleus and TA. In contrast, differences in antioxidant gene expression between soleus and TA became less apparent following two HS bouts. Overall, this data indicates that HS alters expression of genes associated with antioxidant defense in a skeletal muscle type specific manner.This work was funded by the National Research Initiative Competitive Grant no. 2008‐35206‐18817 from the USDA Cooperative State Research, Education, and Extension Service.

Diesel engine exhaust initiates a sequence of pulmonary and cardiovascular effects in rats.

This study was designed to determine the sequence of events leading to cardiopulmonary effects following acute inhalation of diesel engine exhaust in rats. Rats were exposed for 2 h to diesel engine exhaust (1.9 mg/m3), and biological parameters related to antioxidant defense, inflammation, and procoagulation were examined after 4, 18, 24, 48, and 72 h. This in vivo inhalation study showed a pulmonary anti-oxidant response (an increased activity of the anti-oxidant enzymes glutathione peroxidase and superoxide dismutase and an increase in heme oxygenase-1 protein, heme oxygenase activity, and uric acid) which precedes the inflammatory response (an increase in IL-6 and TNF-α). In addition, increased plasma thrombogenicity and immediate anti-oxidant defense gene expression in aorta tissue shortly after the exposure might suggest direct translocation of diesel engine exhaust components to the vasculature but mediation by other pathways cannot be ruled out. This study therefore shows that different stages in oxidative stress are not only affected by dose increments but are also time dependent.

Proline and glycinebetaine induce antioxidant defense gene expression and suppress cell death in cultured tobacco cells under salt stress

Salt stress causes oxidative damage and cell death in plants. Plants accumulate proline and glycinebetaine (betaine) to mitigate detrimental effects of salt stress. The aim of this study was to investigate the protective effects of proline and betaine on cell death in NaCl-unadapted tobacco (Nicotiana tabacum) Bright Yellow-2 suspension-cultured cells subjected to salt stress. Salt stress increased reactive oxygen species (ROS) accumulation, lipid peroxidation, nuclear deformation and degradation, chromatin condensation, apoptosis-like cell death and ATP contents. Neither proline nor betaine affected apoptosis-like cell death and G(1) phase population, and increased ATP contents in the 200mM NaCl-stressed cells. However, both of them effectively decreased ROS accumulation and lipid peroxidation, and suppressed nuclear deformation and chromatin condensation induced by severe salt stress. Evans Blue staining experiment showed that both proline and betaine significantly suppressed increment of membrane permeability induced by 200mM NaCl. Furthermore, among the ROS scavenging antioxidant defense genes studied here, mRNA levels of salicylic acid-binding (SAbind) catalase (CAT) and lignin-forming peroxidase (POX) were found to be increased by proline and betaine under salt stress. It is concluded that both proline and betaine provide a protection against NaCl-induced cell death via decreasing level of ROS accumulation and lipid peroxidation as well as improvement of membrane integrity.

Analysis of gene expression profiles in insulin-sensitive tissues from pre-diabetic and diabetic Zucker diabetic fatty rats

Insulin resistance occurs early in the disease process, preceding the development of type 2 diabetes. Therefore, the identification of molecules that contribute to insulin resistance and leading up to type 2 diabetes is important to elucidate the molecular pathogenesis of the disease. To this end, we characterized gene expression profiles from insulin-sensitive tissues, including adipose tissue, skeletal muscle, and liver tissue of Zucker diabetic fatty (ZDF) rats, a well characterized type 2 diabetes animal model. Gene expression profiles from ZDF rats at 6 weeks (pre-diabetes), 12 weeks (diabetes), and 20 weeks (late-stage diabetes) were compared with age- and sex-matched Zucker lean control (ZLC) rats using 5000 cDNA chips. Differentially regulated genes demonstrating > 1.3-fold change at age were identified and categorized through hierarchical clustering analysis. Our results showed that while expression of lipolytic genes was elevated in adipose tissue of diabetic ZDF rats at 12 weeks of age, expression of lipogenic genes was decreased in liver but increased in skeletal muscle of 12 week old diabetic ZDF rats. These results suggest that impairment of hepatic lipogenesis accompanied with the reduced lipogenesis of adipose tissue may contribute to development of diabetes in ZDF rats by increasing lipogenesis in skeletal muscle. Moreover, expression of antioxidant defense genes was decreased in the liver of 12-week old diabetic ZDF rats as well as in the adipose tissue of ZDF rats both at 6 and 12 weeks of age. Cytochrome P450 (CYP) genes were also significantly reduced in 12 week old diabetic liver of ZDF rats. Genes involved in glucose utilization were downregulated in skeletal muscle of diabetic ZDF rats, and the hepatic gluconeogenic gene was upregulated in diabetic ZDF rats. Genes commonly expressed in all three tissue types were also observed. These profilings might provide better fundamental understanding of insulin resistance and development of type 2 diabetes.