8-hydroxy-2' -deoxyguanosine (8-OHdG): A critical biomarker of oxidative stress and carcinogenesis

Graphene oxide induces cytotoxicity and oxidative stress in bluegill sunfish cells

Graphene oxide (GO) is considered a promising material for biological application due to its unique properties. However, the potential toxicity of GO to aquatic organism particularly bluegill sun fish cells (BF-2) is unexplored or remains poorly understood. GO-induced cytotoxicity and oxidative stress in BF-2 cells were assessed using a battery of biomarkers. Two different biological assays (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide and neutral red uptake were used to evaluate the cytotoxicity of GO on BF-2 cells. It was found that GO induced dose- and time-dependent cytotoxicity on BF-2 cells. BF-2 cells exposed to lower concentration of GO (40 μg ml^-1 ) for 24 induced morphological changes when compared to their respective controls. As evidence for oxidative stress lipid peroxidation, superoxide dismutase, catalase, reactive oxygen species and 8-hydroxy-2'-deoxyguanosine levels were increased and glutathione levels were found to decline in BF-2 cells after treatment with GO. Our findings demonstrate that GO when exposed to BF-2 fish cells cause oxidative stress.

Monocyte-derived exosomes upon exposure to cigarette smoke condensate alter their characteristics and show protective effect against cytotoxicity and HIV-1 replication

Smoking is known to exacerbate HIV-1 pathogenesis, especially in monocytes, through the oxidative stress pathway. Exosomes are known to alter HIV-1 pathogenesis through inter-cellular communication. However, the role of exosomes in smoking-mediated HIV-1 pathogenesis is unknown. In this study, we investigated the effect of cigarette smoke condensate (CSC) on the characteristics of monocyte-derived exosomes and their influence on HIV-1 replication. Initially, we demonstrated that CSC reduced total protein and antioxidant capacity in exosomes derived from HIV-1-infected and uninfected macrophages. The exosomes from CSC-treated uninfected cells showed a protective effect against cytotoxicity and viral replication in HIV-1-infected macrophages. However, exosomes derived from HIV-1-infected cells lost their protective capacity. The results suggest that the exosomal defense is likely to be more effective during the early phase of HIV-1 infection and diminishes at the latter phase. Furthermore, we showed CSC-mediated upregulation of catalase in exosomes from uninfected cells, with a decrease in the levels of catalase and PRDX6 in exosomes derived from HIV-1-infected cells. These results suggest a potential role of antioxidant enzymes, which are differentially packaged into CSC-exposed HIV-1-infected and uninfected cell-derived exosomes, on HIV-1 replication of recipient cells. Overall, our study suggests a novel role of exosomes in tobacco-mediated HIV-1 pathogenesis.

Anticancer potential of ZnO nanoparticle-ferulic acid conjugate on Huh-7 and HepG2 cells and diethyl nitrosamine induced hepatocellular cancer on Wistar albino rat

Drawbacks and limitations of recently available therapies to hepatocellular cancer (HCC) devoted the scientist to focus on emerging new strategies. ZnO nanoparticles (ZnONPs) based chemotherapeutics has been emanating as a promising approach to maximize therapeutic synergy facilitating the discovery of novel multitargeted combinations. In the present study we conjugated ZnONPs with ferulic acid (ZnONPs-FAC) characterized by computational, spectroscopic and microscopic techniques. In vitro anticancer potential has been evaluated by assessing cell viability, morphology, ROS generation, mitochondrial membrane permeability, comet assay, immunofluorescent staining of 8-OHdG, Ki67 and γ-H2AX, cell cycle analysis and western blot analysis and in vivo anticancer potential against DEN induced HCC was analyzed by histopathological and immunohistochemical methods. The results revealed that ZnONPs-FAC induces cell death through apoptosis and can suppress the DEN-induced HCC. Our study documents therapeutic potential of nanoparticle conjugated with phytochemicals, suggesting a new platform for combinatorial chemotherapy.

Modulatory Effect of Fermented Papaya Extracts on Mammary Gland Hyperplasia Induced by Estrogen and Progestin in Female Rats

Fermented papaya extracts (FPEs) are obtained by fermentation of papaya by Aspergillus oryzae and yeasts. In this study, we investigated the protective effects of FPEs on mammary gland hyperplasia induced by estrogen and progestogen. Rats were randomly divided into 6 groups, including a control group, an FPE-alone group, a model group, and three FPE treatment groups (each receiving 30, 15, or 5 ml/kg FPEs). Severe mammary gland hyperplasia was induced upon estradiol benzoate and progestin administration. FPEs could improve the pathological features of the animal model and reduce estrogen levels in the serum. Analysis of oxidant indices revealed that FPEs could increase superoxide dismutase (SOD) and glutathione peroxidase (GSH-Px) activities, decrease malondialdehyde (MDA) level in the mammary glands and serum of the animal models, and decrease the proportion of cells positive for the oxidative DNA damage marker 8-oxo-dG in the mammary glands. Additionally, estradiol benzoate and progestin altered the levels of serum biochemical compounds such as aspartate transaminase (AST), total bilirubin (TBIL), and alanine transaminase (ALT), as well as hepatic oxidant indices such as SOD, GSH-Px, MDA, and 8-oxo-2′-deoxyguanosine (8-oxo-dG). These indices reverted to normal levels upon oral administration of a high dose of FPEs. Taken together, our results indicate that FPEs can protect the mammary glands and other visceral organs from oxidative damage.

Protective effect of pomegranate juice on retinal oxidative stress in streptozotocin-induced diabetic rats

AIM

To investigate the effect of pomegranate juice (PJ) intake on overall oxidation status in retinas of diabetic rats.

METHODS

Twenty-seven rats were divided into four groups as control (CO), diabetic (DM), control treated with PJ (CO-PJ), and diabetic treated with PJ (DM-PJ).The retina tissues were used to determine 8-hydroxy-2'-deoxyguanosine (8OHdG), malondialdehyde (MDA), reduced glutathione (GSH) levels, and the enzyme activities of superoxide dismutase (SOD) and glutathione peroxidase (GSH-Px).

RESULTS

The levels of 8OHdG and MDA were significantly increased in the retina of DM group compared to CO group (P=0.001, P<0.001 respectively). Both 8OHdG and MDA levels were decreased in PJ-DM group compared to DM group (P=0.004, P<0.001 respectively). The activities of antioxidant enzymes GSH, SOD, and GDH-Px were significantly decreased in the retina of DM group compared to CO group (P≤0.01). GSH and GSH-Px activities were higher in PJ-DM group compared with DM group (P=0.010, P=0.042, respectively) but SOD activity was not statistically different (P=0.938).

CONCLUSION

PJ intake is found to be effective in decreasing oxidative end products, and in increasing the activities of antioxidant enzymes in diabetic retinas of rats, which suggests it may be effective against oxidative stress in diabetic retinas.

The food-borne pathogen Campylobacter jejuni responds to the bile salt deoxycholate with countermeasures to reactive oxygen species

Bile plays an important role in digestion, absorption of fats, and the excretion of waste products, while concurrently providing a critical barrier against colonization by harmful bacteria. Previous studies have demonstrated that gut pathogens react to bile by adapting their protein synthesis. The ability of pathogens to respond to bile is remarkably complex and still incompletely understood. Here we show that Campylobacter jejuni, a leading bacterial cause of human diarrheal illness worldwide, responds to deoxycholate, a component of bile, by altering global gene transcription in a manner consistent with a strategy to mitigate exposure to reactive oxygen stress. More specifically, continuous growth of C. jejuni in deoxycholate was found to: 1) induce the production of reactive oxygen species (ROS); 2) decrease succinate dehydrogenase activity (complex II of the electron transport chain); 3) increase catalase activity that is involved in H₂O₂ breakdown; and 4) result in DNA strand breaks. Congruently, the addition of 4-hydroxy-TEMPO (TEMPOL), a superoxide dismutase mimic that reacts with superoxide, rescued the growth of C. jejuni cultured in the presence of deoxycholate. We postulate that continuous exposure of a number of enteric pathogens to deoxycholate stimulates a conserved survival response to this stressor.

Evaluation of chromosomal DNA damage, cytotoxicity, cytostasis, oxidative DNA damage and their relationship with endocrine hormones in patients with acute organophosphate poisoning

Pesticides are commonly used compounds in agriculture. Especially, organophosphates (OPs) are among the extensively used pesticides. Therefore, OPs poisoning is common, especially in underdeveloped and developing countries. Primary aim of this study was to research the effects of acute OPs poisoning on genome instability in the individuals' lymphocytes with acute OPs poisoning both by using the cytokinesis-block micronucleus cytome (CBMN-cyt) assay to examine chromosome/genome damage, cell proliferation index and cell death rate and by using the plasma 8-hydroxy-2'-deoxyguanosine (8-OHdG) levels to determine oxidative DNA damage. Secondary aim of this study was also to assess whether a relation exists between endocrine hormones and the genome damage in acute OPs poisoning. In the study, blood samples were analysed of 13 patients before and after treatment admitted to the Department of Intensive Care Unit with acute OPs poisoning and of 13 healthy subjects of similar age and sex. The present study demonstrates that genome damage (micronucleus; MN and nucleoplasmic bridges; NPBs frequencies), apoptotic and necrotic cell frequencies increased in lymphocytes of patients with acute OPs poisoning before treatment and decreased after treatment. The present study also show that CBMN cyt assay parameters and 8-OHdG levels could be affected by some endocrine hormones such as E2, fT3, fT4, GH, IGF-1, FSH, LH, TSH, PRL, but not be related to ACTH and tT levels in acute OPs poisoning. In conclusion, it is believed that this is the first study to evaluate the chromosomal/oxidative DNA damage, cell proliferation, cell death and their associations with endocrine hormones in acute OPs poisoning. These preliminary findings need to be supported by further studies with larger sample sizes.

Hyperglycaemia, oxidative stress and inflammatory markers

INTRODUCTION

The increasing prevalence of hyperglycaemia implicates a state of oxidative stress and inflammation. Traditional and emerging biomarkers associated with increasing hyperglycaemia were assessed to clarify their role they play in hyperglycaemia.

RESULTS

309 participants attending a rural diabetic screening program were categorised into control and quintile groups based upon glucose levels: 1st quintile - <4.5 mmol/L and 4th, 5th quintile - >6.1 mmol/L. Significant results were obtained for anthropometric data and biochemical markers - glucose, HbA1c and total cholesterol (P < 0.001); oxidative stress: glutathione (P < 0.001), glutathione:glutathione disulfide and 8-hydroxy-2-deoxyguanosine (P < 0.05). Interleukin -1β and inflammatory marker ratios IL-6/IL-10, IL-1β/IL-10, MCP-1/IL-10, IGF-1/IL-10 and IL-6/IL-1β were significant (P < 0.05).

CONCLUSION

This study provided further evidence that inflammatory and oxidative stress biomarkers may contribute to diagnostic information associated with preclinical increases in BGL. Further we have provided a unique study in the analysis of ratios of inflammatory biomarkers and correlations with increasing BGL.

Treatment with a Catalytic Superoxide Dismutase (SOD) Mimetic Improves Liver Steatosis, Insulin Sensitivity, and Inflammation in Obesity-Induced Type 2 Diabetes

Oxidative stress and persistent inflammation are exaggerated through chronic over-nutrition and a sedentary lifestyle, resulting in insulin resistance. In type 2 diabetes (T2D), impaired insulin signaling leads to hyperglycemia and long-term complications, including metabolic liver dysfunction, resulting in non-alcoholic fatty liver disease (NAFLD). The manganese metalloporphyrin superoxide dismustase (SOD) mimetic, manganese (III) meso-tetrakis (N-ethylpyridinium-2-yl) porphyrin (MnP), is an oxidoreductase known to scavenge reactive oxygen species (ROS) and decrease pro-inflammatory cytokine production, by inhibiting nuclear factor kappa-light-chain-enhancer of activated B cells (NF-κB) activation. We hypothesized that targeting oxidative stress-induced inflammation with MnP would assuage liver complications and enhance insulin sensitivity and glucose tolerance in a high-fat diet (HFD)-induced mouse model of T2D. During 12 weeks of feeding, we saw significant improvements in weight, hepatic steatosis, and biomarkers of liver dysfunction with redox modulation by MnP treatment in HFD-fed mice. Additionally, MnP treatment improved insulin sensitivity and glucose tolerance, while reducing serum insulin and leptin levels. We attribute these effects to redox modulation and inhibition of hepatic NF-κB activation, resulting in diminished ROS and pro-inflammatory cytokine production. This study highlights the importance of controlling oxidative stress and secondary inflammation in obesity-mediated insulin resistance and T2D. Our data confirm the role of NF-κB-mediated inflammation in the development of T2D, and demonstrate the efficacy of MnP in preventing the progression to disease by specifically improving liver pathology and hepatic insulin resistance in obesity.

Hydrogen sulfide-producing cystathionine γ-lyase is critical in the progression of kidney fibrosis

Cystathionine γ-lyase (CSE), the last key enzyme of the transsulfuration pathway, is involved in the production of hydrogen sulfide (H₂S) and glutathione (GSH), which regulate redox balance and act as important antioxidant molecules. Impairment of the H₂S- and GSH-mediated antioxidant system is associated with the progression of chronic kidney disease (CKD), characterized by kidney fibrosis and dysfunction. Here, we evaluated the role of CSE in the progression of kidney fibrosis after unilateral ureteral obstruction (UUO) using mice deficient in the Cse gene. UUO of wild-type mice reduced the expression of H₂S-producing enzymes, CSE, cystathionine β-synthase, and 3-mercaptopyruvate sulfurtransferase in the obstructed kidneys, resulting in decreased H₂S and GSH levels. Cse gene deletion lowered H₂S and GSH levels in the kidneys. Deleting the Cse gene exacerbated the decrease in H₂S and GSH levels and increase in superoxide formation and oxidative damage to proteins, lipids, and DNA in the kidneys after UUO, which were accompanied by greater kidney fibrosis, deposition of extracellular matrixes, expression of α-smooth muscle actin, tubular damage, and infiltration of inflammatory cells. Furthermore, Cse gene deletion exacerbated mitochondrial fragmentation and apoptosis of renal tubule cells after UUO. The data provided herein constitute in vivo evidence that Cse deficiency impairs renal the H₂S- and GSH-producing activity and exacerbates UUO-induced kidney fibrosis. These data propose a novel therapeutic approach against CKD by regulating CSE and the transsulfuration pathway.

Linking arsenite- and cadmium-generated oxidative stress to microsatellite instability in vitro and in vivo

Mismatch repair (MMR) corrects replicative errors and minimizes DNA damage that occurs frequently in microsatellites. MMR deficiency is manifested as microsatellite instability (MSI), which contributes to hypermutability and cancer pathogenesis. Genomic instability, including MSI and chromosomal instability, appears to be responsible for the carcinogenesis of arsenic and cadmium, common contaminants in our environment. However, few studies have addressed arsenic- or cadmium-induced MSI, especially its potential link with arsenic- or cadmium-generated oxidative stress, due to the lack of quantifiable MSI assays and cost-effective animal models. Here, using a dual-fluorescent reporter, we demonstrate that sub-lethal doses of cadmium or arsenite, but not arsenate, increased the MSI frequency in human colorectal cancer cells. Arsenite- and cadmium-induced MSI occurred concomitantly with increased levels of reactive species and oxidative DNA damage, and with decreased levels of MMR proteins. However, N-acetyl-l-cysteine (NAC) suppressed arsenite- and cadmium-induced MSI and oxidative stress while restoring the levels of MMR proteins in the cells. Similarly, MSI was induced separately by arsenite and cadmium, and suppressed by NAC, in zebrafish in a fluorescinated PCR-based assay with newly-developed microsatellite markers and inter-segmental comparisons. Of five selected antioxidants examined, differential effects were exerted on the MSI induction and cytotoxicity of both arsenite and cadmium. Compared to MMR-proficient cells, MMR-deficient cells were more resistant to arsenic-mediated and cadmium-mediated cytotoxicity. Our findings demonstrate a novel linkage between arsenite-generated and cadmium-generated oxidative stress and MSI induction. Our findings also caution that antioxidants must be individually validated before being used for preventing arsenite- and cadmium-induced MSI that is associated with cancer development.

Chronic Obstructive Pulmonary Disease-Derived Circulating Cells Release IL-18 and IL-33 under Ultrafine Particulate Matter Exposure in a Caspase-1/8-Independent Manner

Chronic obstructive pulmonary disease (COPD) is considered the fourth-leading causes of death worldwide; COPD is caused by inhalation of noxious indoor and outdoor particles, especially cigarette smoke that represents the first risk factor for this respiratory disorder. To mimic the effects of particulate matter on COPD, we isolated peripheral blood mononuclear cells (PBMCs) and treated them with combustion-generated ultrafine particles (UFPs) obtained from two different fuel mixtures, namely, pure ethylene and a mixture of ethylene and dimethylfuran (the latter mimicking the combustion of biofuels). UFPs were separated in two fractions: (1) sub-10 nm particles, named nano organic carbon (NOC) particles and (2) primarily soot particles of 20–40 nm and their agglomerates (200 nm). We found that both NOC and soot UFPs induced the release of IL-18 and IL-33 from unstable/exacerbated COPD-derived PBMCs. This effect was associated with higher levels of mitochondrial dysfunction and derived reactive oxygen species, which were higher in PBMCs from unstable COPD patients after combustion-generated UFP exposure. Moreover, lower mRNA expression of the repairing enzyme OGG1 was associated with the higher levels of 8-OH-dG compared with non-smoker and smokers. It was interesting that IL-18 and IL-33 release from PBMCs of unstable COPD patients was not NOD-like receptor 3/caspase-1 or caspase-8-dependent, but rather correlated to caspase-4 release. This effect was not evident in stable COPD-derived PBMCs. Our data suggest that combustion-generated UFPs induce the release of caspase-4-dependent inflammasome from PBMCs of COPD patients compared with healthy subjects, shedding new light into the biology of this key complex in COPD.

Exposure to crack cocaine causes adverse effects on marine mussels Perna perna

Our study aimed to evaluate crack cocaine effects in different life stages of the marine mussel Perna perna. For this purpose, fertilization rate, embryo-larval development, lysosomal membrane stability and DNA strand breaks were assessed. Effect concentrations in gametes and in larval development were found after 1h (IC₅₀=23.53mg·L^-1) and 48h (IC₅₀=16.31mg·L^-1), respectively. The highest tested concentration showing no acute toxicity (NOEC) was 10mg·L^-1, while the lowest observed effect concentration (LOEC) was 20mg·L^-1. NOEC concerning embryo-larval development was 0.625mg·L^-1, while the LOEC was 1.25mg·L^-1. Cyto-genotoxic effects were evidenced in mussels exposed to crack cocaine concentrations ranging from 5 to 500μg·L^-1. Our results report the first data on effects of an illicit drug to marine organisms and should encourage further ecotoxicological studies of these contaminants of emerging concern in coastal ecosystems.

NR1D1 enhances oxidative DNA damage by inhibiting PARP1 activity

Cancer cells exhibit an elevated intracellular level of reactive oxygen species (ROS) because of their accelerated metabolism, mitochondrial dysfunction, and antioxidant deficit. The oxidative stress in cancer cells may provide clinical benefits, which can be associated with a better response to anticancer therapies. Therefore, identifying the regulatory pathway of oxidative stress in cancer cells is important in the development of therapeutic targets that enhance sensitivity to ROS-generating anticancer therapies. Here, we report that nuclear receptor subfamily 1, group D, member 1 (NR1D1; Rev-erbα) inhibited DNA repair of ROS-induced DNA damage in breast cancer cells. NR1D1 interacted with poly(ADP-ribose) polymerase 1 (PARP1) and subsequently inhibited catalytic activity of PARP1. NR1D1 enhanced accumulation of DNA damage, which increased sensitivity of breast cancer cells to oxidative stress. Our findings suggest that NR1D1 could be a therapeutic target for breast cancer treatment, especially in those patients treated with ROS-inducing chemotherapeutic agents.

Methionine Sulfoxide Reductase A Deficiency Exacerbates Cisplatin-Induced Nephrotoxicity via Increased Mitochondrial Damage and Renal Cell Death

AIMS

Methionine sulfoxide reductase A (MsrA), which is abundantly localized in the mitochondria, reduces methionine-S-sulfoxide, scavenging reactive oxygen species (ROS). Cisplatin, an anticancer drug, accumulates at high levels in the mitochondria of renal cells, causing mitochondrial impairment that ultimately leads to nephrotoxicity. Here, we investigated the role of MsrA in cisplatin-induced mitochondrial damage and kidney cell death using MsrA gene-deleted (MsrA^-/-) mice.

RESULTS

Cisplatin injection resulted in increases of ROS production, methionine oxidation, and oxidative damage in the kidneys. This oxidative stress was greater in MsrA^-/- mouse kidneys than in wild-type (MsrA^+/+) mouse kidneys. MsrA gene deletion exacerbated cisplatin-induced reductions in the expression and activity of MsrA and MsrBs, and the expression of thioredoxin 1, glutathione peroxidase 1 and 4, mitochondrial superoxide dismutase, cystathionine-β-synthase, and cystathionine-γ-lyase. Cisplatin induced swelling, cristae loss, and fragmentation of mitochondria with increased lipid peroxidation, more so in MsrA^-/- than in MsrA^+/+ kidneys. The ratio of mitochondrial fission regulator (Fis1) to fusion regulator (Opa1) was higher in MsrA^-/- than MsrA^+/+ mice. MsrA deletion exacerbated cisplatin-induced increases in Bax to Bcl-2 ratio, cleaved caspase-3 level, and apoptosis, whereas MsrA overexpression attenuated cisplatin-induced oxidative stress and apoptosis.

INNOVATION

MsrA gene deletion in mice exacerbates cisplatin-induced renal injury through increases of mitochondrial susceptibility, whereas MsrA overexpression protects cells against cisplatin.

CONCLUSION

This study demonstrates that MsrA protects kidney cells against cisplatin-induced methionine oxidation, oxidative stress, mitochondrial damage, and apoptosis, suggesting that MsrA could be a useful target protein for the treatment of cisplatin-induced nephrotoxicity. Antioxid. Redox Signal. 27, 727-741.

The cost of reproduction in women: Reproductive effort and oxidative stress in premenopausal and postmenopausal American women

OBJECTIVES

Life history theory predicts a trade-off between female investment in reproduction and somatic maintenance, which can result in accelerated senescence. Oxidative stress has been shown to be a causal physiological mechanism for accelerated aging and a possible contributor to this trade-off. We aimed to test the hypothesis for the existence of significant associations between measures of reproductive effort and the level of oxidative stress biomarkers in premenopausal and postmenopausal American women.

METHODS

Serum samples and questionnaire data were collected from 63 premenopausal and postmenopausal women (mean age 53.4 years), controls in the Connecticut Thyroid Health Study, between May 2010 and December 2013. Samples were analyzed for levels of 8-OHdG and Cu/Zn-SOD using immunoassay method.

RESULTS

Levels of oxidative damage (8-OHdG) but not oxidative defense (Cu/Zn-SOD) were negatively associated with parity and number of sons in premenopausal women (r = -0.52 for parity, r = -0.52 for number of sons, P < .01). Together, measures of reproductive effort, women's BMI, age, and menopausal status explained around 15% of variance in level of 8-OHdG. No association between reproductive effort characteristics and oxidative damage was found for postmenopausal women.

CONCLUSIONS

We found no evidence of a trade-off between somatic maintenance as measured by 8-OHdG and reproductive effort in women from this American population. On the contrary, higher gravidity and parity in premenopausal women was associated with lower damage to cellular DNA caused by oxidative stress. These results highlight the importance of population variation and environmental conditions when testing the occurrence of life-history trade-offs.

Effect of iron supplementation during lactation on maternal iron status and oxidative stress: A randomized controlled trial

We examined the effect of iron-containing prenatal vitamin-mineral supplements taken postpartum on biomarkers of iron status and oxidative stress. Lactating women (n = 114) were randomly assigned to consume daily one iron-free prenatal vitamin-mineral supplement plus either 27 mg of iron or placebo for approximately 3.5 months. The placebo group took the tablets between meals, while those given iron took the tablets either with (Fe-W) or between meals (Fe-B). Blood and urine samples were collected before and after the supplementation period to analyze hemoglobin (Hb), ferritin, hepcidin, transferrin saturation (TfSat), total plasma iron, and biomarkers of oxidative stress (isoprostane and 8-hydroxy-2-deoxyguanosine (8-OHdG)) and inflammation (C-reactive protein (CRP) and alpha-1-acid glycoprotein (AGP)). There was a trend toward a greater change in Hb among women in the Fe-B group compared to placebo (+2.5 vs. -3.7 g/L, respectively, p = 0.063). When the iron groups were combined, there was a greater change in Hb (+1.4 g/L) compared to placebo (p = 0.010). There were trends toward greater changes in TfSat (p = 0.087) and total plasma iron (p = 0.065) in the iron groups compared to placebo, yet no significant differences between the three groups in change in hepcidin (p = 0.291), isoprostane (p = 0.319), or 8-OHdG (p = 0.659), nor in change in ferritin among those with elevated CRP at baseline (60% of women; p = 0.946); among those without elevated CRP (40% of women), ferritin increased more in the iron groups compared to placebo (p = 0.001). Iron consumption during lactation moderately increased iron status, particularly among women without elevated CRP, and increased Hb, but did not significantly increase oxidative stress.

The effect of sunblock against oxidative stress in farmers: a pilot study

Farmers are frequently exposed to ultraviolet (UV) radiation which causes various diseases by inducing oxidative stress. This study aimed to assess the effects of sunblock on oxidative stress in the body. Eighty-seven farmers were divided into two groups: those who wore sunblock for five days and those who did not. The total antioxidant capacity (TAC) in urine, which is an antioxidant indicator, and 8-hydroxy-2-deoxyguanosine (8-OHdG) levels in urine, an oxidative stress indicator, were measured. The urinary TAC of sunblock users was significantly higher than that of non-users, but urinary 8-OHdG levels were not significantly different. Even after adjustment for potential confounders, urinary TAC was found to be markedly increased with sunblock usage. These results suggest that sunblock is effective in preventing oxidative stress among farmers. In addition, they show that urinary TAC can be used as a good effect marker of oxidative stress caused by UV exposure.

Not breathing is not an option: How to deal with oxidative DNA damage

Oxidative DNA damage constitutes a major threat to genetic integrity, and has thus been implicated in the pathogenesis of a wide variety of diseases, including cancer and neurodegeneration. 7,8-dihydro-8oxo-deoxyGuanine (8-oxo-G) is one of the best characterised oxidative DNA lesions, and it can give rise to point mutations due to its miscoding potential that instructs most DNA polymerases (Pols) to preferentially insert Adenine (A) opposite 8-oxo-G instead of the correct Cytosine (C). If uncorrected, A:8-oxo-G mispairs can give rise to C:G→A:T transversion mutations. Cells have evolved a variety of pathways to mitigate the mutational potential of 8-oxo-G that include i) mechanisms to avoid incorporation of oxidized nucleotides into DNA through nucleotide pool sanitisation enzymes (by MTH1, MTH2, MTH3 and NUDT5), ii) base excision repair (BER) of 8-oxo-G in DNA (involving MUTYH, OGG1, Pol λ, and other components of the BER machinery), and iii) faithful bypass of 8-oxo-G lesions during replication (using a switch between replicative Pols and Pol λ). In the following, the fate of 8-oxo-G in mammalian cells is reviewed in detail. The differential origins of 8-oxo-G in DNA and its consequences for genetic stability will be covered. This will be followed by a thorough discussion of the different mechanisms in place to cope with 8-oxo-G with an emphasis on Pol λ-mediated correct bypass of 8-oxo-G during MUTYH-initiated BER as well as replication across 8-oxo-G. Furthermore, the multitude of mechanisms in place to regulate key proteins involved in 8-oxo-G repair will be reviewed. Novel functions of 8-oxo-G as an epigenetic-like regulator and insights into the repair of 8-oxo-G within the cellular context will be touched upon. Finally, a discussion will outline the relevance of 8-oxo-G and the proteins involved in dealing with 8-oxo-G to human diseases with a special emphasis on cancer.

Treatment of diabetic mice with the SGLT2 inhibitor TA-1887 antagonizes diabetic cachexia and decreases mortality

A favorable effect of an inhibitor of the sodium–glucose cotransporter 2 (SGLT2i) on mortality of diabetic patients was recently reported, although mechanisms underlying that effect remained unclear. Here, we examine SGLT2i effects on survival of diabetic mice and assess factors underlying these outcomes. To examine SGLT2i treatment effects in a model of severe diabetes, we fed genetically diabetic db/db mice a high-fat diet and then assessed outcomes including diabetic complications between SGLT2i TA-1887-treated and control mice. We also compare effects of SGLT2i TA-1887 with those of lowering blood glucose levels via insulin treatment. Untreated db/db mice showed remarkable weight loss, or cachexia, while TA-1887-treated mice did not but rather continued to gain weight at later time points and decreased mortality. TA-1887 treatment prevented pancreatic beta cell death, enhanced preservation of beta cell mass and endogenous insulin secretion, and increased insulin sensitivity. Moreover, TA-1887 treatment attenuated inflammation, oxidative stress, and cellular senescence, especially in visceral white adipose tissue, and antagonized endothelial dysfunction. Insulin treatment of db/db mice also prevented weight loss and antagonized inflammation and oxidative stress. However, insulin treatment had less potent effects on survival and prevention of cellular senescence and endothelial dysfunction than did TA-1887 treatment. SGLT2i treatment prevents diabetic cachexia and death by preserving function of beta cells and insulin target organs and attenuating complications. SGLT2i treatment may be a promising therapeutic strategy for type 2 diabetes patients with morbid obesity and severe insulin resistance.

Sodium-glucose cotransporter 2 inhibitor (SGLT2i) has a favorable effect on mortality of diabetic subjects, but the mechanism stays unclear. Taichi Sugizaki at Kumamoto University examined SGLT2i effects in severe diabetic obese mice, and discovered that they showed prolonged survival without pathological weight loss, or cachexia. As with SGLT2i, Insulin also prevented cachexia, improved pancreatic beta cell function, insulin sensitivity and some organ damages. However, what makes SGLT2i important was to suppress cellular aging or vessel inflammation, while insulin accelerated those developments, which may lead to a result that SGLT2i has contributed to prolonged survival more than insulin. SGLT2i demonstrates an association with survival period upon maintaining good condition of pancreatic beta cells and insulin target organs, providing insight into strategies for treatment of severe diabetes.

Potential application of the oxidative nucleic acid damage biomarkers in detection of diseases

Reactive oxygen species (ROS) are generated after exposure to harmful environmental factors and during normal cellular metabolic processes. The balance of the generating and scavenging of ROS plays a significant role in living cells. The accumulation of ROS will lead to oxidative damage to biomolecules including nucleic acid. Although many types of oxidative nucleic acid damage products have been identified, 8-oxo-7,8-dihydro-2’-deoxyguanosine (8-oxodG) and 8-oxo-7,8-dihydroguanosine (8-oxoG) has been commonly chosen as the biomarkers of oxidative damage to DNA and RNA, respectively. It has been demonstrated that oxidative damage to nucleic acid is an initiator in pathogenesis of numerous diseases. Thus, oxidative nucleic acid damage biomarkers have the potential to be utilized for detection of diseases. Herein, we reviewed the relationship of oxidative nucleic acid damage and development of various diseases including cancers (colorectal cancer, gastrointestinal cancer, breast cancer, lung cancer, epithelial ovarian carcinoma, esophageal squamous cell carcinoma), neurodegenerative disorders and chronic diseases (diabetes and its complications, cardiovascular diseases). The potential of oxidative nucleic acid damage biomarkers for detection of diseases and drug development were described. Moreover, the approaches for detection of these biomarkers were also summarized.

Mitochondrial Function in Allergic Disease

PURPOSE OF THE REVIEW

The connections between allergy, asthma and metabolic syndrome are becoming increasingly clear. Recent research suggests a unifying mitochondrial link between the diverse phenotypes of these interlinked morbidities. The scope of this review is to highlight cellular mechanisms, epidemiology and environmental allergens influencing mitochondrial function and its importance in allergy and asthma. We briefly also consider the potential of mitochondria-targeted therapies in prevention and cure.

RECENT FINDINGS

Recent research has shown allergy, asthma and metabolic syndrome to be linked to mitochondrial dysfunction. Environmental pollutants and allergens are observed to cause mitochondrial dysfunction, primarily by inducing oxidative stress and ROS production. Malfunctioning mitochondria change the bioenergetics of the cell and its metabolic profile to favour systemic inflammation, which drives all three types of morbidities. Given the existing experimental evidence, approaches targeting mitochondria (e.g. antioxidant therapy and mitochondrial replacement) are being conducted in relevant disease models-with some progressing towards clinical trials, making mitochondrial function the focus of translational therapy research in asthma, allergy and linked metabolic syndrome.

The effects of high and low doses of folic acid on oxidation of protein levels during pregnancy: a randomized double-blind clinical trial

Objective Oxidants include important active molecules which are created in the body and attack biological molecules especially lipids, carbohydrates, nucleic acids and proteins, and cause oxidation and various diseases in the body. Antioxidants existing in the body help to avoid the incidence of these injuries. Pregnant women are among those where oxidation of biological molecules may do irreparable damage to them and their embryos. So, the purpose of this study was to review the effect of folic acid with both high (5 mg/day) and low (0.5 mg/day) doses on the changes of oxidative protein in reducing plasma homocystein concentration during pregnancy. Materials and methods Forty-five pregnant women participated in this study. They were divided into two groups: group 1 included 23 women who received 5 mg/day folic acid and group 2 included 23 women who took 0.5 mg/day folic acid before pregnancy till the 36th week pregnancy. We measured the biochemical variables in the serum of pregnant women at the beginning and at the end of the study. Results Folic acid reduced plasma homocytein in both low and high dose groups (p = 0.035, p = 0.012, respectively). Also, the results showed that folic acid prescription led to reduce plasma level of carbonyl groups in both low and high dose groups (p = 0.01, p = 0.03, respectively). Furthermore, the results showed that there is no significant difference between two groups and folic acid affects both groups equally. Conclusion It is possible that folic acid administration can reduce plasma homocysteine and carbonyl levels during pregnancy in dose independent manner.

Oxidative stress and respiratory symptoms due to human exposure to polycyclic aromatic hydrocarbons (PAHs) in Kumasi, Ghana

Studies of polycyclic aromatic hydrocarbons (PAHs) and its metabolites in PM10, soils, rat livers and cattle urine in Kumasi, Ghana, revealed high concentrations and cancer potency. In addition, WHO and IARC have reported an increase in cancer incidence and respiratory diseases in Ghana. Human urine were therefore collected from urban and control sites to: assess the health effects associated with PAHs exposure using malondialdehyde (MDA) and 8-hydroxy-2-deoxyguanosine (8-OHdG); identify any association between OH-PAHs, MDA, 8-OHdG with age and sex; and determine the relationship between PAHs exposure and occurrence of respiratory diseases. From the results, urinary concentrations of the sum of OH-PAHs (∑OHPAHs) were significantly higher from urban sites compared to the control site. Geometric mean concentrations adjusted by specific gravity, GM_SG, indicated 2-OHNaphthalene (2-OHNap) (6.01 ± 4.21 ng/mL) as the most abundant OH-PAH, and exposure could be through the use of naphthalene-containing-mothballs in drinking water purification, insect repellent, freshener in clothes and/or "treatment of various ailments". The study revealed that exposure to naphthalene significantly increases the occurrence of persistent cough (OR = 2.68, CI: 1.43-5.05), persistent headache (OR = 1.82, CI: 1.02-3.26), tachycardia (OR = 3.36, CI: 1.39-8.10) and dyspnea (OR = 3.07, CI: 1.27-7.43) in Kumasi residents. Highest level of urinary 2-OHNap (224 ng/mL) was detected in a female, who reported symptoms of persistent cough, headache, tachycardia, nasal congestion and inflammation, all of which are symptoms of naphthalene exposure according to USEPA. The ∑OHPAHs, 2-OHNap, 2-3-OHFluorenes, and -OHPhenanthrenes showed a significantly positive correlation with MDA and 4-OHPhenanthrene with 8-OHdG, indicating possible lipid peroxidation/cell damage or degenerative disease in some participants. MDA and 8-OHdG were highest in age group 21-60. The present study showed a significant sex difference with higher levels of urinary OH-PAHs in females than males.

Role of DNA polymerase β oxidized nucleotide insertion in DNA ligation failure

Production of reactive oxygen and nitrogen species (ROS), such as hydrogen peroxide, superoxide and hydroxyl radicals, has been linked to cancer, and these oxidative molecules can damage DNA. Base excision repair (BER), a major repair system maintaining genome stability over a lifespan, has an important role in repairing oxidatively induced DNA damage. Failure of BER leads to toxic consequences in ROS-exposed cells, and ultimately can contribute to the pathobiology of disease. In our previous report, we demonstrated that oxidized nucleotide insertion by DNA polymerase β (pol β) impairs BER due to ligation failure and leads to formation of a cytotoxic repair intermediate. Biochemical and cytotoxic effects of ligation failure could mediate genome stability and influence cancer therapeutics. In this review, we discuss the importance of coordination between pol β and DNA ligase I during BER, and how this could be a fundamental mechanism underlying human diseases such as cancer and neurodegeneration. A summary of this work was presented in a symposium at the International Congress of Radiation Research 2015 in Kyoto, Japan.

Electrozymographic evaluation of the attenuation of arsenic induced degradation of hepatic SOD, catalase in an in vitro assay system by pectic polysaccharides of Momordica charantia in combination with curcumin

Momordica charantia (MC) fruit known as bitter gourd, is of potential nutritional and medicinal value. The objectives of the present in vitro study were to evaluate the efficacy of bioactive pectic polysaccharides (CCPS) of MC along with another well-known bioactive compound curcumin in the abrogation of hepatocellular oxidative stress persuaded by sodium arsenite. Electrozymographic method was developed for the assessment of superoxide dismutase (SOD) and catalase activities of liver tissues maintained under an in vitro system. A significant association of CCPS of MC in combination with curcumin was found in the alleviation of oxidative stress induced by sodium arsenite in liver slice. Generated data pointed out that CCPS of MC and curcumin separately or in combination can offer significant protection against alterations in malondialdehyde (MDA), conjugated diene (CD) and antioxidative defense (SOD, CAT) markers. Furthermore, results of hepatic cell DNA degradation strongly supported that both these co-administrations have efficacy in preventing cellular damage. This is the first information of extracted polysaccharides from MC preventing arsenic induced damage in a liver slice of rat.

Oxidative Stress and Immune Responses During Hepatitis C Virus Infection in Tupaia belangeri

Hepatitis C virus (HCV) is a leading cause of chronic liver disease, cirrhosis, and hepatocellular carcinoma. To address the molecular basis of HCV pathogenesis using tupaias (Tupaia belangeri), we characterized host responses upon HCV infection. Adult tupaias were infected with HCV genotypes 1a, 1b, 2a, or 4a. Viral RNA, alanine aminotransferase, anti-HCV core and anti-nonstructural protein NS3 antibody titres, reactive oxygen species (ROS), and anti-3β-hydroxysterol-Δ24reductase (DHCR24) antibody levels were measured at 2-week intervals from 0 to 41 weeks postinfection. All HCV genotypes established infections and showed intermittent HCV propagation. Moreover, all tupaias produced anti-core and anti-NS3 antibodies. ROS levels in sera and livers were significantly increased, resulting in induction of DHCR24 antibody production. Similarly, lymphocytic infiltration, disturbance of hepatic cords, and initiation of fibrosis were observed in livers from HCV-infected tupaias. Intrahepatic levels of Toll-like receptors 3, 7, and 8 were significantly increased in all HCV-infected tupaias. However, interferon-β was only significantly upregulated in HCV1a- and HCV2a-infected tupaias, accompanied by downregulation of sodium taurocholate cotransporting polypeptide. Thus, our findings showed that humoral and innate immune responses to HCV infection, ROS induction, and subsequent increases in DHCR24 auto-antibody production occurred in our tupaia model, providing novel insights into understanding HCV pathogenesis.

Principal Aspects Regarding the Maintenance of Mammalian Mitochondrial Genome Integrity

Mitochondria have emerged as key players regarding cellular homeostasis not only due to their contribution regarding energy production through oxidative phosphorylation, but also due to their involvement in signaling, ion regulation, and programmed cell death. Indeed, current knowledge supports the notion that mitochondrial dysfunction is a hallmark in the pathogenesis of various diseases. Mitochondrial biogenesis and function require the coordinated action of two genomes: nuclear and mitochondrial. Unfortunately, both intrinsic and environmental genotoxic insults constantly threaten the integrity of nuclear as well as mitochondrial DNA. Despite the extensive research that has been made regarding nuclear genome instability, the importance of mitochondrial genome integrity has only recently begun to be elucidated. The specific architecture and repair mechanisms of mitochondrial DNA, as well as the dynamic behavior that mitochondria exert regarding fusion, fission, and autophagy participate in mitochondrial genome stability, and therefore, cell homeostasis.

The NADPH oxidase NOX2 mediates loss of parvalbumin interneurons in traumatic brain injury: human autoptic immunohistochemical evidence

Pharmacological interventions for traumatic brain injury (TBI) are limited. Together with parvalbumin (PV) loss, increased production of reactive oxygen species (ROS) by the NADPH oxidase NOX enzymes represents a key step in TBI. Here, we investigated the contribution of NOX2-derived oxidative stress to the loss of PV immunoreactivity associated to TBI, performing immunohistochemistry for NOX2, 8-hydroxy-2′-deoxyguanosine (8OHdG) and PV on post mortem brain samples of subjects died following TBI, subjects died from spontaneous intracerebral hemorrhage (SICH) and controls (CTRL). We detected an increased NOX2 expression and 8OHdG immunoreactivity in subjects died from TBI with respect to CTRL and SICH. NOX2 increase was mainly observed in GABAergic PV-positive interneurons, with a minor presence in microglia. No significant differences in other NADPH oxidase isoforms (NOX1 and NOX4) were detected among experimental groups. NOX2-derived oxidative stress elevation appeared a specific TBI-induced phenomenon, as no alterations in the nitrosative pathway were detected. Our results suggest that NOX2-derived oxidative stress might play a crucial role in the TBI-induced loss of PV-positive interneurons.

Preoperative transcatheter arterial chemotherapy may suppress oxidative stress in hepatocellular carcinoma cells and reduce the risk of short-term relapse

In this study, we aim to investigate oxidative stress in hepatocellular carcinoma (HCC) tissues in patients receiving preoperative transcatheter arterial chemotherapy (TAC) and its association with prognosis. A total of 89 HCC patients enrolled in this study, 39 received preoperative TAC 1 week before surgery (pTAC group) and 50 did not (non-pTAC group). All patients underwent hepatectomy and postoperative TAC and were followed up to 400 weeks. Samples of liver tissue without HCC and hepatitis (n = 15) served as normal controls. Cellular levels of 8-hydroxy-2′-deoxyguanosine (8-OHdG), TP53, and p21^waf1/cip1 were measured in both cancer and surrounding tissues using an immunohistochemistry assay. Taken together, our data suggested that preoperative TAC might postpone postoperative HCC relapse within 1 year via suppression of tumor cells by induction of high levels of oxidative stress.

Analysis of blood markers for early breast cancer diagnosis

PURPOSE

Breast cancer is the most common neoplasm in women and has the highest associated mortality rate. Rapid detection programmes can provide early diagnosis and increase the chances of survival. There are no specific tumor biomarkers for the early phase of the disease. The primary aim of this study was to search a blood biomarker with levels that exceeded the normal range established in the general population that could be used to screen breast cancer.

METHODS/PATIENTS

Case-control study. Conventional as well as research (NGAL, EGFR and 8-OHdG) tumor biomarkers were analyzed.

RESULTS

A total of 126 women were enrolled (cases: 63 patients with local breast cancer; Controls: 63 healthy women). Significant differences were found in patients with higher levels of the conventional markers, Ca15.3, CEA, Cyfra 21.1 and NSE. However, when commercial cut-off values were used, only Ca 15.13 was significant. In the group of research biomarkers, significantly higher levels of EGFR were found in the control group, and of 8-OHdG in the case group. Using logistic regression analysis and a ROC curve, an equation composed of five markers, Ca 15.3, NSE, NGAL, EGFR and 8-OHdG, which yielded a correct diagnostic probability of breast cancer of 91.8% was obtained.

CONCLUSIONS

8-OHdG has been identified as a new potential marker for screening early stage breast cancer. In addition, a model that combines five blood markers that can be used as a diagnostic test in certain groups of patients has been developed. New studies with a larger sample size are needed to verify the results obtained.

Risk assessment of environmental exposure to heavy metals in mothers and their respective infants

Exposure to heavy metals can cause renal injury, which has been well documented in occupational exposure. Studies of low exposure in the general population, however, are still scarce, particularly for vulnerable populations such as mothers and young children. This study evaluated exposure to heavy metals, and biomarkers of renal function and oxidative stress in 944 lactating mothers and their infants and investigated the role of the interaction between heavy metals and oxidative stress in altering renal function. Mother and infant urine samples were analyzed to measure mercury (Hg), cadmium (Cd), and lead (Pb) concentrations for determining body-burden exposure; N-acetyl-β-d-glucosaminidase (NAG), α₁-microglobulin (α₁-MG), albumin (ALB), and creatinine (Cr) concentrations for determining early renal injury; and 8-hydroxy-2-deoxyguanosine (8-OHdG) and malondialdehyde (MDA) concentrations for determining oxidative stress. The median concentrclearlyations in mothers presented as μg/g Cr (infants as μg/l) for Hg, Cd, and Pb were 0.695 (0.716), 0.322 (0.343), and 3.97 (5.306) respectively. The mothers and their infants had clearly been exposed to heavy metals and had levels higher than the reference values reported for the general populations of USA, Germany, and Canada. Multiple regression analyses clearly demonstrated associations between urinary heavy metals in quartiles and several renal and oxidative biomarkers in mothers and to a lesser extent their infants. ß coefficients for urinary excretions of MDA, 8-OHdG, ALB, α₁-MG, NAG, and Cr in mothers were high in the highest quartile of Hg (1.183-51.29μg/g Cr or 1.732-106.95μg/l), Cd (0.565-765.776μg/g Cr or 0.785-1347.0μg/l), and Pb (6.606-83.937μg/g Cr or 9.459-80.826μg/l), except Pb was not associated with ALB. Infants in the highest Pb quartile (9.293-263.098μg/l) had the highest ß coefficients of urinary excretion of MDA, 8-OHdG, ALB, NAG, and Cr. Significant increasing trend in biomarkers across the quartiles of the three metals was seen in both mothers and infants (p_trend <0.001). A receiver operating characteristic analysis supported the predictive abilities of the four renal biomarkers in discriminating between low versus high metal quartiles. The interaction between heavy metals and oxidative stress contributed to the high excretions of renal biomarkers, but the mechanism remains unclear. These findings add to the limited evidence that low exposure to heavy metals in the general population is associated with alterations in renal function that could eventually progress to renal damage if exposure continues and that children are more susceptible due to the immaturity of their body organs.

PARP-1/PAR Activity in Cultured Human Lens Epithelial Cells Exposed to Two Levels of UVB Light

This study investigated poly(ADP-ribose) polymerase-1 (PARP-1) activation in cultured human lens epithelial cells exposed to two levels of UVB light (312 nm peak wavelength), 0.014 and 0.14 J cm^-2 ("low" and "high" dose, respectively). At the low dose, PARP-1 and poly(ADP-ribose) (PAR) polymers acted to repair DNA strand breaks rapidly with no subsequent major effects on either cell morphology or viability. However, following the high UVB dose, there was a dramatic second phase of PARP-1 activation, 90 min later, which included a sudden reappearance of DNA strand breaks, bursts of reactive oxygen species (ROS) formation within both the mitochondria and nucleus, a translocation of PAR from the nucleus to the mitochondria and an ultimate 70% loss of cell viability occurring after 24 h. The results provide evidence for an important role for PARP-1 in protecting the human lens epithelium against low levels of UVB light, and possibly participating in the triggering of cell death following exposure to toxic levels of radiation.

Modulation of Pancreatic Islets' Function and Survival During Aging Involves the Differential Regulation of Endoplasmic Reticulum Stress by p21 and CHOP

AIMS

Although endoplasmic reticulum (ER) stress is recognized as a major mechanism causing pancreatic dysfunction in diabetes, little is known on how aging modulates the process. Here, we compared the response with ER stress, viability, and insulin release from pancreatic islets of young (6 weeks) or aged (14 months) mice.

RESULTS

Islets from aged mice were more sensitive to ER stress than their younger counterparts; they exhibited more pronounced unfolded protein response (UPR) and caspase activation and displayed compromised insulin release after high-glucose stimulation. Genetic ablation of p21 sensitized the islets to ER stress, especially in the aged group, whereas CHOP ablation was protective for islets from both aged and younger animals. Ciclopirox (CPX), an iron chelator that stimulates p21 expression, protected islets from glucotoxicity and mice from diet-induced diabetes, especially in the aged group in a manner that was both p21 and CHOP dependent.

INNOVATION

For the first time, the study shows that age-dependent susceptibility to diet-induced diabetes is associated with the activity of p21 and CHOP in pancreatic islets and that CPX protects islets from glucotoxicity and mice from diabetes in an age-dependent manner.

CONCLUSIONS

Our results identify ER stress as an age-dependent modifier of islet survival and function by mechanisms implicating enhancement of CHOP activity and inhibition of the protective activity of p21. These findings suggest that interventions restoring the homeostatic activity of ER stress, by agents such as CPX, may be particularly beneficial for the management of diabetes in the elderly. Antioxid. Redox Signal. 27, 185-200.

Assessment of genotoxicity amongst smokers, alcoholics, and tobacco chewers of North India using micronucleus assay and urinary 8-hydroxyl-2'-deoxyguanosine, as biomarkers

The main objective of the present study was to screen the genotoxicity caused by individual and combined habits of smoking, tobacco chewing, and alcohol consumption in human population of North India. Study recruited 67 male subjects aged 25 to 65 years. Buccal mucosal cells were subjected to micronucleus (MN) assay, and 8-hydroxyl-2-deoxyguanosine (8-OHdG) was estimated in their urine samples. Number and shape of the MN cells varied in the buccal epithelium of different groups. Maximum number of MN (0.47%) were found in tobacco chewers followed by smokers (0.45%) and alcoholics (0.44%) (P < 0.05). These results reciprocated the concentration of urinary 8-OHdG. Maximum value for 8-OHdG was also recorded in tobacco chewers (21.07 ± 5.51 mg/mg creatinine) followed by smokers (20.25 ± 3.96 mg/mg creatinine) and alcoholics (19.06 ± 3.41 mg/mg creatinine) (P < 0.05). Combined effects of these agents were found to be statistically different from individual effects. Carcinogenic compounds present in cigarette smoke, nitrosamines found in solid tobacco, and acetaldehyde, a metabolic product of alcohol, induce oxidative stress that manifests into genotoxicity. In conclusion, demographical differences occur in the genotoxicity caused by these three habits. MN assay and urinary 8-OHdG are simple, noninvasive, and reliable biomarkers of genotoxicity.

Corticotropin-releasing factor receptor-1 modulates biomarkers of DNA oxidation in Alzheimer's disease mice

Increased production of hydroxyl radical is the main source of oxidative damage in mammalian DNA that accumulates in Alzheimer’s disease (AD). Reactive oxygen species (ROS) react with both nuclear DNA (nDNA) and mitochondrial DNA (mtDNA) to generate 8-hydroxy-2’-deoxyguanosine (8-OHdG), both of which can be measured in the urine. Knowledge of this pathway has positioned measurement of urine 8-OHdG as a reliable index of DNA oxidation and a potential biomarker target for tracking early cellular dysfunction in AD. Furthermore, epigenetic studies demonstrate decreased global DNA methylation levels (e.g. 5-methyl-2’-deoxycytidine, 5-mdC) in AD tissues. Moreover, stress hormones can activate neuronal oxidative stress which will stimulate the release of additional stress hormones and result in damages to hippocampal neurons in the AD brain. Our previous work suggests that treating AD transgenic mice the type-1 corticotropin-releasing factor receptor (CRFR1) antagonist, R121919, to reduce stress signaling, prevented onset of cognitive impairment, synaptic/dendritic loss and Aβ plaque accumulation. Therefore, to investigate whether levels of DNA oxidation can be impacted by the same therapeutic approach, urine levels of hydrogen peroxide, 8-OHdG, 5-mdC and total antioxidant capacity (TAC) were analyzed using an AD Tg mouse model. We found that Tg animals had an 80% increase in hydrogen peroxide levels compared to wild type (Wt) counterparts, an effect that could be dramatically reversed by the chronic administration with R121919. A significant decrease of 8-OHdG levels was observed in Tg mice treated with CRFR1 antagonist. Collectively our data suggest that the beneficial effects of CRFR1 antagonism seen in Tg mice may be mechanistically linked to the modulation of oxidative stress pathways.

Antioxidants reduce neurodegeneration and accumulation of pathologic Tau proteins in the auditory system after blast exposure

Cochlear neurodegeneration commonly accompanies hair cell loss resulting from aging, ototoxicity, or exposures to intense noise or blast overpressures. However, the precise pathophysiological mechanisms that drive this degenerative response have not been fully elucidated. Our laboratory previously demonstrated that non-transgenic rats exposed to blast overpressures exhibited marked somatic accumulation of neurotoxic variants of the microtubule-associated protein, Tau, in the hippocampus. In the present study, we extended these analyses to examine neurodegeneration and pathologic Tau accumulation in the auditory system in response to blast exposure and evaluated the potential therapeutic efficacy of antioxidants on short-circuiting this pathological process. Blast injury induced ribbon synapse loss and retrograde neurodegeneration in the cochlea in untreated animals. An accompanying perikaryal accumulation of neurofilament light chain and pathologic Tau oligomers were observed in neurons from both the peripheral and central auditory system, spanning from the spiral ganglion to the auditory cortex. Due to its coincident accumulation pattern and well-documented neurotoxicity, our results suggest that the accumulation of pathologic Tau oligomers may actively contribute to blast-induced cochlear neurodegeneration. Therapeutic intervention with a combinatorial regimen of 2,4-disulfonyl α-phenyl tertiary butyl nitrone (HPN-07) and N-acetylcysteine (NAC) significantly reduced both pathologic Tau accumulation and indications of ongoing neurodegeneration in the cochlea and the auditory cortex. These results demonstrate that a combination of HPN-07 and NAC administrated shortly after a blast exposure can serve as a potential therapeutic strategy for preserving auditory function among military personnel or civilians with blast-induced traumatic brain injuries.

Gradient-on-a-Chip with Reactive Oxygen Species Reveals Thresholds in the Nucleus Response of Cancer Cells Depending on the Matrix Environment

Oxidative stress-mediated cancer progression depends on exposure to reactive oxygen species (ROS) in the extracellular matrix (ECM). To study the impact of ROS levels on preinvasive breast cancer cells as a function of ECM characteristics, we created a gradient-on-a-chip in which H₂O₂ progressively mixes with the cell culture medium within connected microchannels and diffuses upward into the ECM of the open cell culture window. The device utilizes a paper-based microfluidic bifurcating mixer insert to prevent leakage and favor an even fluid distribution. The gradient was confirmed by measuring H₂O₂ catalyzed into oxygen, and increasing oxidative DNA damage and protective (AOP2) response were recorded in 2D and ECM-based 3D cell cultures. Interestingly, the impact of ROS on nuclear shape and size (annunciating phenotypical changes) was governed by the stiffness of the collagen I matrix, suggesting the existence of thresholds for the phenotypic response to microenvironmental chemical exposure depending on ECM conditions.

CDK4/6 and autophagy inhibitors synergistically induce senescence in Rb positive cytoplasmic cyclin E negative cancers

Deregulation of the cell cycle machinery is a hallmark of cancer. While CDK4/6 inhibitors are FDA approved (palbociclib) for treating advanced estrogen receptor-positive breast cancer, two major clinical challenges remain: (i) adverse events leading to therapy discontinuation and (ii) lack of reliable biomarkers. Here we report that breast cancer cells activate autophagy in response to palbociclib, and that the combination of autophagy and CDK4/6 inhibitors induces irreversible growth inhibition and senescence in vitro, and diminishes growth of cell line and patient-derived xenograft tumours in vivo. Furthermore, intact G1/S transition (Rb-positive and low-molecular-weight isoform of cyclin E (cytoplasmic)-negative) is a reliable prognostic biomarker in ER positive breast cancer patients, and predictive of preclinical sensitivity to this drug combination. Inhibition of CDK4/6 and autophagy is also synergistic in other solid cancers with an intact G1/S checkpoint, providing a novel and promising biomarker-driven combination therapeutic strategy to treat breast and other solid tumours.

CDK4/6-Cyclin D pathway is often deregulated in cancer; therefore specific inhibitors have been developed. Here the authors show that treatment with CDK4/6 inhibitors activate autophagy in breast cancer cells; thus, combination of such inhibitors with autophagy inhibitors results in a synergistic effect on tumour growth.

Chronic treatment with a smart antioxidative nanoparticle for inhibition of amyloid plaque propagation in Tg2576 mouse model of Alzheimer's disease

The present study aimed to assess whether our newly developed redox nanoparticle (RNP^N) that has antioxidant potential decreases Aβ levels or prevents Aβ aggregation associated with oxidative stress. The transgenic Tg2576 Alzheimer’s disease (AD) mice were used to investigate the effect of chronic ad libitum drinking of RNP^N solution for 6 months, including memory and learning functions, antioxidant activity, and amyloid plaque aggregation. The results showed that RNP^N-treated mice had significantly attenuated cognitive deficits of both spatial and non-spatial memories, reduced oxidative stress of lipid peroxide, and DNA oxidation. RNP^N treatment increased the percent inhibition of superoxide anion and glutathione peroxidase activity, neuronal densities in the cortex and hippocampus, decreased Aβ(1-40), Aβ(1-42) and gamma (γ)-secretase levels, and reduced Aβ plaque observed using immunohistochemistry analysis and thioflavin S staining. Our results suggest that RNP^N may be a promising candidate for AD therapy because of its antioxidant properties and reduction in Aβ aggregation, thereby suppressing its adverse side effect.

Association of Metabolic Syndrome and Oxidative DNA Damage in HIV/AIDS Patients

HIV-infected adults may be likely to have metabolic syndrome (MS) at younger ages and in the absence of obesity compared with general population. In the present study, we determined prevalence of MS and its association with oxidative deoxy nucleic acid (DNA) damage in HIV-1 infected patients with different ART status. We used plasma level of the oxidized base, 8-hydroxy-2-deoxyguanosine (8-OHdG), as a biomarker of oxidative DNA damage. To measure plasma 8-OHdG we used 8-OHdG enzyme-linked, immunosorbent assay. The biomarkers of MS were insulin resistance, Cholesterol/HDL ratio, Waist circumference and Hypertension. MS and oxidative DNA damage were significantly higher in HIV-positive patients with second line ART and first line ART than ART-naive patients. In a logistic regression analysis, increased MS was positively associated with the increased DNA damage (OR: 29.68, 95%:13.47, CI: 65.40) P = 0.0001. ART plays a significant role in the development of MS and oxidative DNA damage in HIV-positive patients taking antiretroviral therapy. Awareness and knowledge of MS and DNA damage in HIV/AIDS patients may prove helpful to clinicians to manage non-AIDS diseases such as cardiovascular disease and cancer. To determine exact role of ART in induction of MS and DNA damage larger studies are warranted.

Study of the Effect of Bisphenol A on Oxidative Stress in Children with Autism Spectrum Disorders

The role of bisphenol A (BPA) in autism was investigated in 49 children (mean age = 5.950 ± 1.911 years) with autism spectrum disorders (ASDs) and 40 comparable age and sex matched children used as controls (mean age = 5.333 ± 2.279 years). In addition, 8-Hydroxydeoxyguanosine (8-oxodG) was also studied as a biomarker of oxidative stress in the same set of two selected groups. The results showed that both BPA and 8-oxodG were significantly higher in children with autism than those of control children (p values = 0.025 and 0.0001, respectively). There were positive correlations between both BPA and 8-oxodG with ASDs severity (r = 0.400 and 0.805, respectively), these correlations were highly significant (p values = 0.004 and 0.001, respectively). There was a significance positive correlation between BMI and BPA, but the correlation between BMI and 8-oxodG was not significant in children with autism. The observed results revealed that BPA may increase oxidative stress resulting in mitochondrial dysfunction that affecting the behavior and functioning of ASDs children.

Oxidative stress and brain morphology in individuals with depression, anxiety and healthy controls

Oxidative stress is a biological process, caused by an imbalance between reactive oxygen species (ROS) and antioxidants, in favour of the ROS. This imbalance leads to oxidative damage to lipids, proteins and DNA and ultimately cell death. Studies in rodents have shown that the brain, particularly the amygdala and hippocampus, is sensitive to oxidative stress, although studies on the association between oxidative stress and brain morphology in humans are lacking. Oxidative stress has also been associated with major depressive disorder (MDD) and may be related to volumetric abnormalities in the amygdala and hippocampus in MDD and anxiety disorders. In this study we aimed to examine the association between two robust measures of oxidative damage in plasma (8-OHdG and F2-isoprostanes) and volume of the hippocampus and amygdala in a large sample of individuals with and without MDD and/or anxiety (N=297). In secondary analyses, we examine whether this association is similar in patients and controls. 8-OHdG and F2-isoprostanes plasma levels were determined using liquid chromatography tandem mass spectrometry and volume of the hippocampus and amygdala and hippocampal subfields was determined using Freesurfer. We found no association between plasma markers (or interaction with MDD and/or anxiety disorder diagnosis) and subcortical volume, suggesting that peripheral oxidative stress damage is not associated with subcortical brain volume.