Reactive Oxygen Species

Mutations in human mitochondrial DNA (mtDNA) can cause mitochondrial disease and have been associated with neurodegenerative disorders, cancer, diabetes and aging. Yet our progress toward delineating the precise contributions of mtDNA mutations to these conditions is impeded by the limited availability of faithful transmitochondrial animal models. Here, we report a method for the isolation of mutations in mouse mtDNA and its implementation for the generation of a collection of over 150 cell lines suitable for the production of transmitochondrial mice. This method is based on the limited mutagenesis of mtDNA by proofreading-deficient DNA-polymerase γ followed by segregation of the resulting highly heteroplasmic mtDNA population by means of intracellular cloning. Among generated cell lines, we identify nine which carry mutations affecting the same amino acid or nucleotide positions as in human disease, including a mutation in the ND4 gene responsible for 70% of Leber Hereditary Optic ...

Percentage of viable sperms has good potential to reflect male fertilizing potential. In the present study, an attempt was made to find out the percentage of viable sperms in normal and abnormal ejaculates and influence of reactive oxygen species in affecting the viability of sperm. Malondialdehyde (MDA) in seminal plasma of normal and abnormal ejaculates was measured by Thiobarbituric Acid method and percentage of viable sperms was assessed by Eosin-Nigrosin staining. The results revealed that the abnormal semen samples have significantly lower number of viable spermatozoa (59.06 +/- 9.63% vs. 68.33 +/- 5.46%, P < 0.05) and higher levels of MDA (2.53 +/- 0.66 vs. 1.66 +/- 0.37 nmol/ml, P < 0.05) as compared to normal. A significant negative correlation was found between seminal MDA level and sperm viability. Based on the results obtained from the present study, we suggest that viability of sperm is an authentic parameter to assess male fertility potential and it can be affect...

Resveratrol is a natural molecule with antioxidant action. Moreover, resveratrol is also considered to be a molecule with anti-inflammatory action, an effect attributed to suppression of prostaglandin (PG) biosynthesis. The aim of the present study was to investigate the effects of resveratrol, a polyphenol present in most red wines, on reactive oxygen species formation as well as on arachidonic acid (AA) release, cyclooxygenase expression, and PG synthesis in murine resident peritoneal macrophages. Results show that resveratrol exerted a strong inhibitory effect on superoxide radical (O2−) and hydrogen peroxide (H2O2) produced by macrophages stimulated by lipopolysaccharides (LPS) or phorbol esters (PMA). Resveratrol also significantly decreased [3H]AA release induced by LPS and PMA or by exposure to O2− or H2O2. Resveratrol treatment caused a significant impairment of cyclooxygenase-2 (COX-2) induction stimulated by LPS and PMA or by O2− or H2O2 exposure. These effects of resveratrol on [3H]AA release and COX-2 overexpression were correlated with a marked reduction of PG synthesis. Our results indicate that the antioxidant action of resveratrol affects AA mobilization and COX-2 induction.

The European Cooperation in Science and Technology (COST) provides an ideal framework to establish multi-disciplinary research networks. COST Action BM1203 (EU-ROS) represents a consortium of researchers from different disciplines who are dedicated to providing new insights and tools for better understanding redox biology and medicine and, in the long run, to finding new therapeutic strategies to target dysregulated redox processes in various diseases. This report highlights the major achievements of EU-ROS as well as research updates and new perspectives arising from its members. The EU-ROS consortium comprised more than 140 active members who worked together for four years on the topics briefly described below. The formation of reactive oxygen and nitrogen species (RONS) is an established hallmark of our aerobic environment and metabolism but RONS also act as messengers via redox regulation of essential cellular processes. The fact that many diseases have been found to be associat...

NPR1 is a key regulator of the salicylic acid (SA) dependent pathogen resistance pathway in plants. In this issue of Cell, Mou and Dong demonstrate that Arabidopsis NPR1 undergoes activation from an inactive oligomer to the active monomer as a result of cellular redox changes induced by SA during systemic acquired resistance.

The aim of this study was to evaluate, in vitro, the effect of iron on the dissolution of bovine enamel powder, when added to two carbonated beverages.Powdered enamel was produced by griding enamel fragments of bovine incisor in a steel pestle and mortar. Particles between 75 and 106 μm were selected using appropriated meshes. At time zero, the carbonated beverage (Coke® or Sprite Zero®) was added to powdered enamel (1 mg enamel powder/10 μL of beverage) and vortexed for 30 s. The sample was immediately centrifuged (11,000 rpm) for 30 s and the supernatant was removed at 1 min 40 s. This procedure was repeated five times with the beverage containing increasing ferrous sulphate concentrations (1.25, 2.5, 5, 10, 15, 30 and 60 mmol/L). The phosphate released in the medium was analysed spectrophotometrically. Data were analysed using ANOVA and Tukey's test (p < 0.05).When iron at 30 and 60 mmol/L was added to Coke®, a significant reduction in the dissolution of powdered enamel was observed when compared to control (11 and 17%, respectively), while lower iron concentrations did not have any effect on enamel powder dissolution. Regarding Sprite Zero®, iron concentrations up to 10 mmol/L had no significant effect, while higher concentrations significantly increased enamel powder dissolution.The results suggest that iron can interfere with the dissolution of dental enamel powder in the presence of acidic beverages and the type of acid in these beverages seems to modulate this effect.

Alcohol consumption is a predominant etiological factor in the pathogenesis of chronic liver diseases, resulting in fatty liver, alcoholic hepatitis, fibrosis/cirrhosis, and hepatocellular carcinoma (HCC). Although the pathogenesis of alcoholic liver disease (ALD) involves complex and still unclear biological processes, the oxidative metabolites of ethanol such as acetaldehyde and reactive oxygen species (ROS) play a preeminent role in the clinical and pathological spectrum of ALD. Ethanol oxidative metabolism influences intracellular signaling pathways and deranges the transcriptional control of several genes, leading to fat accumulation, fibrogenesis and activation of innate and adaptive immunity. Acetaldehyde is known to be toxic to the liver and alters lipid homeostasis, decreasing peroxisome proliferator-activated receptors and increasing sterol regulatory element binding protein activity via an AMP-activated protein kinase (AMPK)-dependent mechanism. AMPK activation by ROS mod...

Oxalates stimulate alterations in renal epithelial cells and thereby induce calcium oxalate (CaOx) stone formation. Bacillus subtilis YvrK gene encodes for oxalate decarboxylase (OxdC) which degrades oxalate to formate and CO2. The present work is aimed to clone the oxdC gene in a mammalian expression vector pcDNA and transfect into Human Embryonic Kidney 293 (HEK293) cells and evaluate the oxdC expression, cell survival rate and oxalate degrading efficiency. The results indicate cell survival rate of HEK293/pcDNAOXDC cells pre-incubated with oxalate was enhanced by 28%. HEK293/pcDNAOXDC cells expressing OxdC treated with oxalate, significantly restored antioxidant activity, mitochondrial membrane potential and intracellular reactive oxygen species (ROS) generation compared with HEK293/pcDNA. Apoptotic marker caspase 3 downregulation illustrates HEK293/pcDNAOXDC cells were able to survive under oxalate-mediated oxidative stress. The findings suggest HEK293 cells expressing oxdC capa...

Al though the aetiology of inflammatory bowel disease (IBD) remains unknown, the pathogenesis is gradually being unravelled, seeming to be the result of a combination of environmental, genetic, and immunological factors in which an uncontrolled immune response within the intestinal lumen leads to inflammation in genetically predisposed individuals. Multifactorial evidence suggests that a defect of innate immune response to microbial agents is involved in IBD. This editorial outlines the immunopathogenesis of IBD and their current and future therapy. We present IBD as a result of dysregulated mucosal response in the intestinal wall facilitated by defects in epithelial barrier function and the mucosal immune system with excessive production of cytokines growth factors, adhesion molecules, and reactive oxygen metabolites, resulting in tissue injury. Established and evolving therapies are discussed in the second part of this editorial and at the end of this section we review new therapi...

Most of the previous studies dealing with the effect of nonsteroidal anti-inflammatory drugs (NSAIDs) on the synthesis of inflammatory mediators involved in joint damage have been done in cells culturedin vitro or in blood cells from patients treated for short periods of time. In this work we have evaluated the long-term effect of aceclofenac, a new NSAID, and diclofenac on the production of a series of inflammatory mediators by blood cells from 30 patients with severe knee osteoarthritis. Both aceclofenac and diclofenac significantly inhibited prostaglandin E2 (PGE2) synthesis by blood mononuclear and polymorphonuclear cells after 180 days of treatment. However, no clear effect was noted on leukotriene B4 (LTB4) and platelet activating factor (PAF) production. The generation of O 2− by polymorphonuclear cells, stimulated with FMLP, was decreased after 15 days of treatment with both drugs, but reached normal values after 180 days. Interleukin-1β (IL-1β) production decreased significantly at 180 days with both drugs in the group of high producer patients. In a few (n=3) patients with high basal mononuclear cell tumor necrosis factor α (TNFα) production, this also decreased on treatment for 180 days with the NSAIDs. In the remaining low TNFα-producing patients, TNFα production tended to increase. Interleukin-6 (IL-6) synthesis was not affected by aceclofenac while it was diminished by diclofenac. The decrease in IL-6 in all treated patients was significantly correlated with a worsening of the clinical condition. On the whole, these data could afford a pathogenetic basic for the long-term employment of these drugs in patients with inflammatory conditions.