bluuebunny/crossref_metadata_2025 huggingface dataset:
Biological activities of berries: From antioxidant capacity to anti‐cancer effects
Authors: Juranić Zorica , Žižak Željko
Published: December 2008

Consumption of berries has been implicated with diverse health benefits, such as prevention of stroke, of age‐related degenerative diseases and cancer. Some berry constituents have been proven to have cancer preventive actions on chemically induced tumors in vivo and cancer suppressive effects in in vitro studies. Many of these effects were attributed to certain berry phytochemicals with high antioxidative potential that could contribute to, or enhance by induction, the endogenous antioxidant properties of living cells or organisms. Producers and the consumers of berry products need more comprehensive and accurate information on the type and level of health benefits that can be expected from different products. The choice of the chemical or biological test that best predicts specific health benefits of berries is crucial to provide targets for berry breeding programmes or to improve processing methods. The aim of this review is to examine the chemical and biological tests developed to characterize the impact of berries on consumer health.
Enhancing beneficial antioxidants in fruits: A plant physiological perspective
Authors: Atkinson C.J. , Nestby R. , Ford Y.Y. , Dodds P.A.A.
Published: December 2008

The aim of this review is to present an outline of the physiological perspectives of beneficial antioxidant production in fruit. The drive to enhance the consumption of fruit and vegetables in the human diet is linked with positive effects of beneficial antioxidants impacting on health promotion. We briefly outline our physiological understanding of environmental processes which induce the production of reactive oxygen species and how antioxidants prevent plant cellular damage. More specifically, we describe the impact that environmental stresses, such as drought and radiation, have on the production of endogenous antioxidants and how these stresses can be incorporated into novel experimental crop growing systems to achieve high antioxidant concentrations in fruits. This includes in particular the use of irrigation application techniques and enhanced light reflectance to increase the concentrations of bioactive compounds such as ellagic acid and ascorbic acid.
Fruit cross‐reactive allergens: A theme of uprising interest for consumers' health
Authors: Marzban Gorji , Mansfeld Agata , Hemmer Wolfgang , Stoyanova Elitza , Katinger Hermann , Machado Margit Laimer Da CÂMara
Published: December 2008

Regular consumption of fruits has a positive influence on human health by disease prevention. However parallel to dietetic benefits, IgE‐mediated fruit allergies have been shown to be an increasing health risk for children and adults in the Northern hemisphere. The spectrum of food allergies ranges from chronical symptoms to more acute problems and even anaphylaxis. Fruit proteins with high primary sequence similarity display also homologous tertiary structures, resulting in similar epitopes to IgEs and consequently in cross‐reactivity. In this review we present the major allergens of stone and pome fruits and discuss the presence of homologous proteins in small fruits. Interestingly these proteins, which might pose an allergenic potential for pre‐sensitised individuals are expressed also in strawberry, raspberry and blueberry, otherwise rich in beneficial biofactors.
The action of berry phenolics against human intestinal pathogens
Authors: Puupponen‐Pimiä Riitta , Nohynek Liisa , Alakomi Hanna‐Leena , Oksman‐Caldentey Kirsi‐Marja
Published: December 2008

Phenolic compounds present in berries selectively inhibit the growth of human gastrointestinal pathogens. Especially cranberry, cloudberry, raspberry, strawberry and bilberry possess clear antimicrobial effects against e.g. salmonella and staphylococcus. Complex phenolic polymers, such as ellagitannins, are strong antibacterial agents present in cloudberry, raspberry and strawberry. Berry phenolics seem to affect the growth of different bacterial species with different mechanisms. Adherence of bacteria to epithelial surfaces is a prerequisite for colonization and infection of many pathogens. Antimicrobial activity of berries may also be related to antiadherence activity of the berries. Utilization of enzymes in berry processing increases the amount of phenolics and antimicrobial activity of the berry products. Antimicrobial berry compounds are likely to have many important applications in the future as natural antimicrobial agents for food industry as well as for medicine.
Total hydroxyoctadecadienoic acid as a marker for lipid peroxidation in vivo
Authors: Yoshida Yasukazu , Hayakawa Mieko , Niki Etsuo
Published: December 2008

An improved method for the measurement of lipid peroxidation in vivo has been recently developed, where total hydroxyoctadecadienoic acid (HODE) and 7‐hydroxycholesterol (FCOH) were determined by GC/MS analysis from physiological samples after reduction with sodium borohydride and saponification by potassium hydroxide. In this method, both free and ester forms of hydroperoxides and ketones as well as hydroxides of linoleic acid and cholesterol are measured as HODE and FCOH, respectively. The ratio of stereo‐isomer, (Z, E)‐HODE/(E, E)‐HODE, could be also measured. In the present study, in order to examine the effect of continuous, slow flux of free radicals in vivo, a water‐soluble radical generator was administered to rats and mice and the amounts of HODE and 8‐isoprostane in plasma and liver were measured. It was found that the administration of free radical‐generating azo compound increased the level of HODE and decreased the (Z, E)‐HODE/(E, E)‐HODE ratio in both plasma and liver. The level of HODE was much higher than 8‐isoprostane.
Studies of phospholipid oxidation by electrospray mass spectrometry: From analysis in cells to biological effects
Authors: Spickett Corinne M. , Dever Gary
Published: December 2008

The oxidation of lipids is important in many pathological conditions and lipid peroxidation products such as 4‐hydroxynonenal (HNE) and other aldehydes are commonly measured as biomarkers of oxidative stress. However, it is often useful to complement this with analysis of the original oxidized phospholipid. Electrospray mass spectrometry (ESMS) provides an informative method for detecting oxidative alterations to phospholipids, and has been used to investigate oxidative damage to cells, and low‐density lipoprotein, as well as for the analysis of oxidized phosphatidylcholines present in atherosclerotic plaque material. There is increasing evidence that intact oxidized phospholipids have biological effects; in particular, oxidation products of 1‐palmitoyl‐2‐arachidonoyl‐sn‐glycerophosphocholine (PAPC) have been found to cause inflammatory responses, which could be potentially important in the progression of atherosclerosis. The effects of chlorohydrin derivatives of lipids have been much less studied, but it is clear that free fatty acid chlorohydrins and phosphatidylcholine chlorohydrins are toxic to cells at concentrations above 10 micromolar, a range comparable to that of HNE and oxidized PAPC. There is some evidence that chlorohydrins have biological effects that may be relevant to atherosclerosis, but further work is needed to elucidate their pro‐inflammatory properties, and to understand the mechanisms and balance of biological effects that could result from oxidation of complex mixtures of lipids in a pathophysiological situation.
Immunohistochemical appearance of HNE‐protein conjugates in human astrocytomas
Authors: Zarkovic Kamelija , Juric Gordana , Waeg Georg , Kolenc Danijela , Zarkovic Neven
Published: December 2008

Gliomas are tumors originating from astrocytes, oligodendrocytes or ependimal cells. Those of astrocytic origin are the most widespread of primary brain tumors and account for more then 60% of all CNS neoplasms.

The current state of knowledge on the associations between tumor etiology and oxidative stress suggests that environmental factors that cause oxidative stress could also induce and promote cancer, especially in case of hereditary predisposition. Among mediators of oxidative stress, lipid peroxidation product 4‐hydroxynonenal (HNE) is of particular relevance in oncology, as it is known to act as a growth‐regulating factor and a signaling molecule. The aim of present study was to investigate by immunohistochemistry the presence of HNE‐modified proteins in different types of astrocytoma. Our study comprised 45 astrocytic tumors. These tumors were graded in accordance with the WHO classification as diffuse astrocytomas (DA), anaplastic astrocytomas (AA) and glioblastomas (GB), while each group comprised 15 tumors. Slides of paraffin‐embedded tumor tissue were stained with hematoxylin‐eosin or were prepared for immunohistochemistry with monoclonal antibodies to HNE‐histidine conjugate. Positive immunohistochemical reaction to HNE was analyzed semi‐quantitatively.

HNE positivity was proportional with malignancy of astrocytomas. The weakest presence of HNE‐histidine adducts was found in DA, followed by AA and GB. Lowest intensity of HNE immunopositivity was present in tumor cells of almost all DA, predominantly around blood vessels. In malignant variants of astrocytoma, AA and GB, HNE positivity was moderate to strong, and diffusely distributed in all tumors.
Do neutrophils produce ozone? An appraisal of current evidence
Authors: Kettle Anthony J. , Winterbourn Christine C.
Published: December 2008

Recently, it was proposed that neutrophils generate ozone. Evidence for the proposal is based largely on three experimental systems using probes that are known to react with ozone. However, further assessment of the findings shows that in each case, there is a plausible alternative explanation. Oxidation of indigo carmine to isatin sulfonic can be accounted for by superoxide. Conversion of vinylbenzoic acid to p‐carboxybenzaldehyde is analogous to the reactions of other styrene derivatives shown to be catalyzed by myeloperoxidase, and more rigorous assessment of alternative explanations is needed before the formation of secosterol oxidation products of cholesterol can be taken as proof of ozone production. We conclude that the evidence for ozone production by neutrophils is not convincing and studies using the same probes to implicate ozone in other biological processes should also be interpreted with caution.
Myeloperoxidase‐induced lipid peroxidation of LDL in the presence of nitrite. Protection by cocoa flavanols
Authors: Schewe Tankred , Sies Helmut
Published: December 2008

Lipid peroxidation (LPO) of low‐density lipoprotein (LDL) is believed to be a pivotal process rendering this plasma lipoprotein atherogenic. Several endogenous factors have been proposed to mediate LPO of LDL, among them myeloperoxidase (MPO), which is active in atherosclerotic lesions, and the plasma level of which has been proposed to be a prognostic parameter for cardiac events. Nitrite, a major oxidation product of nitric oxide, is substrate of MPO and a cofactor of MPO‐mediated LPO under physiological conditions. Dietary flavonoids including (‐)‐epicatechin, a major flavan‐3‐ol in cocoa products, grapes and wine, are substrates of MPO as well as potent inhibitors of LPO in LDL at micromolar concentrations. Moreover, they strongly suppress protein tyrosine nitration of LDL by MPO/nitrite or peroxynitrite. By blunting undesirable MPO‐mediated actions of nitrite, presumably via scavenging of the strong prooxidant and nitrating ˙NO2 radical, dietary flavonoids modulate NO metabolism in a favorable direction and thus counteract endothelial dysfunction. This article gives a survey on recent progress in this field with special reference to own recently published work.
A novel test for identifying genes involved in aldehyde detoxification in the yeast. Increased sensitivity of superoxide‐deficient yeast to aldehydes and their metabolic precursors
Authors: Biliński Tomasz , Kwolek Magdalena , Sas Ewelina , Krynicka Marta , Koziol Sabina , Owsiak‐Teleon Alina , Krzepilko Anna , Bartosz Grzegorz
Published: December 2008

A novel test for the identification of genes involved in aldehyde metabolism is proposed, based on detection of altered sensitivity of the yeast to corresponding alcohols, metabolic precursors of the aldehydes. This attitude enabled to an unexpected detection increased sensitivity of mutants devoid of CuZn‐superoxide dismutase (CuZnSOD) to allyl alcohol (precursor of acrolein) and nonenol. We interpret this finding as due to inactivation of some important element of aldehyde detoxification by increased flux of superoxide in ΔCuZnSOD mutants.
Interaction of hypohalous acids and heme peroxidases with unsaturated phosphatidylcholines
Authors: Spalteholz Holger , Wenske Kathrin , Arnhold JÜRgen
Published: December 2008

The formation of chlorohydrins, bromohydrins, and iodohydrins from 1‐palmitoyl‐2‐oleoyl‐sn‐glycero‐3‐phosphocholine (POPC) by the myeloperoxidase‐hydrogen peroxide‐halide system was evaluated by means of matrix‐assisted laser desorption/ionisation time‐of‐flight (MALDI‐TOF) mass spectrometry. This approach allows to detect different kinds of the halogenation reaction even in one mass spectrum. Using a mixture of Cl−, Br−, I−, and SCN− at physiological concentrations, a bromination of POPC dominates by the MPO‐hydrogen peroxide‐halide system. Hypothiocyanite does apparently not react with the double bond of POPC, but increasing amounts of SCN− cause a decrease of the bromohydrin peaks. An interconversion between different hypohalous acids produced by the myeloperoxidase‐hydrogen peroxide‐halide system determines the pattern of halogenohydrins in POPC. Especially, hypochlorous acid is able to oxidise Br‐ to hypobromous acid.
Carnosine and related dipeptides as quenchers of reactive carbonyl species: From structural studies to therapeutic perspectives
Authors: Aldini Giancarlo , Facino Roberto Maffei , Beretta Giangiacomo , Carini Marina
Published: December 2008

Carnosine (β‐alanyl‐L‐histidine) and related peptides such as homocarnosine (γ‐amino‐butyryl‐histidine), balenine β‐alanyl‐L‐3‐methylhistidine) and anserine β‐alanyl‐L‐1‐methylhistidine) are histidine‐containing dipeptides (HD) particularly abundant in excitable tissues such as nervous system and skeletal muscle. Although their biochemical role is still unknown, several evidences indicate that these endogenous compounds act as quenchers of reactive and cytotoxic carbonyl species. In this presentation we will review the structural evidences and ex vivo data supporting this hypothesis. We first elucidated the reaction mechanism of carnosine as quencher of α, β‐unsaturated aldehydes such as 4‐hydroxy‐trans‐2,3‐nonenal (HNE) and acrolein (ACR) and then demonstrated the efficacy of carnosine and related peptides as detoxifying agents of HNE in spontaneously oxidized rat skeletal muscle, by detecting the corresponding HNE‐Michael adducts in the crude biological matrix by liquid chromatography/electrospray ionization tandem mass spectrometry (LC‐ESI‐MS/MS). Finally, we set‐up and validated a sensitive, selective and specific LC‐ESI‐MS/MS method for the determination of HD and of the corresponding HNE‐Michael adducts to monitor their profile in physiological (aging) and pathological conditions (diabetes, atherosclerosis) characterized by a carbonyl‐mediated degenerative overload. The results obtained, beside to give a contribution to the understanding of the biochemical role of histidine‐dipeptides, provide a strong rational to the design of novel derivatives, active as exogenous agents able to detoxify carbonyl compounds.
Dihydroxynonene mercapturic acid, a urinary metabolite of 4‐hydroxynonenal, as a biomarker of lipid peroxidation
Authors: Peiro GÉRaldine , Alary Jacques , Cravedi Jean‐Pierre , Rathahao Estelle , Steghens Jean‐Paul , Guéraud FranÇOise
Published: December 2008

The objective of our study was to compare the information obtained through the use of three different urinary biomarkers of lipoperoxidation during the time course of a bromotrichloromethane (BrCCl3) induced oxidative stress in rats. These biomarkers were malondialdehyde (MDA) measured by LC/MS after derivatization, the isoprostane 8‐iso‐PGF2αmeasured by enzyme immunoassay and 1,4‐dihydroxynonene mercapturic acid (DHN‐MA), the major 4‐hydroxynonenal urinary metabolite [1], measured by LC‐MS. Male Wistar rats received a single dose of 100 μL/kg BrCCl3per osand lipid peroxidation was estimated every day for a 4‐day‐period after treatment. MDA, 8‐iso‐PGF2αand DHN‐MA significantly increased in response to BrCCl3treatment for this period of time, and DHN‐MA showed the main increase during the 24–48 h period after treatment.
Enantioselective metabolism of (R)‐ and (S)‐4‐hydroxy‐2‐nonenal in rat
Authors: Guéraud FranÇOise , Crouzet Fabienne , Alary Jacques , Rao Dinesh , Debrauwer Laurent , Laurent FranÇOis , Cravedi Jean‐Pierre
Published: December 2008

4‐Hydroxy‐2‐nonenal (HNE) is an endogenous product of lipid peroxidation, which is believed to play a biological role in the pathogenesis of various diseases. HNE is formed as a racemic mixture of (R)‐ and (S)‐ enantiomers. These enantiomers differ in their biological properties. The aim of this study was to investigate separately the in vivo metabolism of the two HNE enantiomers in male rats after intravenous administration of the corresponding radiolabeled compounds and to compare the results with those obtained with the racemic mixture. Although the difference in the excretion rates was not statistically significant, the HPLC profiles of urinary metabolites showed qualitative and quantitative differences between the two enantiomers. The level of 3‐mercapturic acid‐1,4‐dihydroxynonane, which is considered as the major urinary metabolite of HNE, was significantly lower in the case of (S)‐HNE injected rats. In vitro studies using rat liver cytosolic incubations and HNE‐glutathione conjugate as substrate were performed to clarify the intermediate pathways involved in their metabolism. Large differences were obtained in the reduction and retro‐Michael conversion steps of the metabolism between the conjugates originating from the two enantiomers.
Antioxidants prevented oxidative injury of SR induced by Fe2+/H2O2/ascorbate system but failed to prevent Ca2+‐ATPase activity decrease
Authors: Horáková Lubica , Štrosová Miriam , Škuciová Mária
Published: December 2008

Dysfunction of sarcoplasmic reticulum (SR) Ca2+‐ATPase induced by oxidative stress may be a contributing factor to the development of serious age related diseases. Incubation of sarcoplasmic reticulum (SR) vesicles of rabbit skeletal muscles with Fe2+/H2O2/ascorbate decreased the SH group content of SR approximately to 35% and Ca2+‐ATPase activity to 50% of control not oxidized sample. Protein carbonyls increased twofold, lipid peroxidation was also significantly elevated.

The antioxidant effects of trolox, the pyridoindole derivative stobadine and of the standardized extracts from bark of Pinus Pinaster Pycnogenol® (Pyc) and from leaves of Ginkgo biloba (EGb 761) were studied on oxidatively injured SR. All antioxidants exerted preventive effects against the oxidized lipids and protein SH groups of SR vesicles. Trolox and stobadine did not influence protein carbonyl formation, while flavonoid extracts prevented carbonyl generation, probably by binding to protein. The preventive effects of the antioxidants studied on lipids and protein SH groups were however not associated with protection of Ca2+‐ATPase activity. Stobadine and trolox exerted no effect on enzyme activity, Pyc and EGb 761 enhanced the inhibitory effect of Ca2+‐ATPase activity in oxidatively injured SR. Concluding, under the conditions of oxidative stress induced by Fe2+/H2O2/ascorbate against SR of rabbit skeletal muscle, the agents studied demonstrated antioxidant effects yet failed to protect Ca2+‐ATPase activity.
Oxidative damage to Ca2+‐ATPase sarcoplasmic reticulum by HOCl and protective effect of some antioxidants
Authors: Štrosová Miriam , Škuciová Mária , Horáková L'Ubica
Published: December 2008

Injury of rabbit skeletal sarcoplasmic reticulum (SR) induced by hypochlorous acid (HOCl) was studied. HOCl inhibited Ca2+‐ATPase activity in a concentration‐dependent manner (IC50=100 μmol/l). The concentration of 13.5 μmol/l HOCl reduced the level of sulfhydryl (SH) groups by 50%, yet it did not influence the enzyme activity. In comparison with SH group oxidation and enzyme activity inhibition, a significantly longer time was necessary for the generation of protein carbonyls in SR injured by HOCl.

Protective effects of some antioxidants (stobadine, trolox, EGb 761, Pycnogenol®) were studied in SR oxidatively injured by HOCl. Trolox and EGb 761 exerted a protective effect on ATPase activity and on SH groups of SR oxidatively modified by HOCl. Stobadine and Pycnogenol® inhibited markedly protein carbonyl formation. Stobadine was the only antioxidant able to scavenge HOCl. In conclusion, the protective effects of antioxidants against decrease of Ca2+‐ATPase activity induced by HOCl might be caused by protection of SH groups. The compounds with both antioxidant and Ca2+‐ATPase protecting effect offer dual defense against tissue damage occurring, e.g. in aging process.
Hydroxynonenal and uncoupling proteins: A model for protection against oxidative damage
Authors: Echtay Karim S. , Pakay Julian L. , Esteves Telma C. , Brand Martin D.
Published: December 2008

In this mini review we summarize recent studies from our laboratory that show the involvement of superoxide and the lipid peroxidation product 4‐hydroxynonenal in the regulation of mitochondrial uncoupling. Superoxide produced during mitochondrial respiration is a major cause of the cellular oxidative damage that may underlie degenerative diseases and ageing. Superoxide production is very sensitive to the magnitude of the mitochondrial protonmotive force, so can be strongly decreased by mild uncoupling. Superoxide is able to give rise to other reactive oxygen species, which elicit deleterious effects primarily by oxidizing intracellular components, including lipids, DNA and proteins. Superoxide‐induced lipid peroxidation leads to the production of reactive aldehydes, including 4‐hydroxynonenal. These aldehydic lipid peroxidation products are in turn able to modify proteins such as mitochondrial uncoupling proteins and the adenine nucleotide translocase, converting them into active proton transporters. This activation induces mild uncoupling and so diminishes mitochondrial superoxide production, hence protecting against disease and oxidative damage at the expense of energy production.
Inhibition of defective adenylosuccinate lyase by HNE: A neurological disease that may be affected by oxidative stress
Authors: Crifò C. , Siems W. , Soro S. , Salerno C.
Published: December 2008

Adenylosuccinate lyase is an enzyme of fumarase superfamily that participates in the purine biosynthetic pathway, catalysing the nonhydrolytic cleavage of succinyl groups from SAICA ribotide and adenylosuccinate. Enzyme defects are associated with a human inherited disease, which arises from single point mutations to the gene and results in mild to severe psychomotor retardation, epilepsy, muscle wasting, and autistic features. Adenylosuccinate lyase activity is lost to a different extent in the patients. Diminished levels of enzyme have been attributed to loss of catalytic activity, protein instability, or environmental factors. P100A/D422Y mutation represents a feasible model for studying the effect of cell milieu on the activity of the impaired enzyme. The defective enzyme is inhibited by micromolar concentrations of trans‐4‐hydroxy‐2‐nonenal (HNE), a major product of membrane peroxidation that has been found to accumulate in brain tissues of patients with neurodegenerative disorders. It is suggested that inactivation of defective adenylosuccinate lyase by HNE and other membrane peroxidation products may account, at least in part, for the impairment of neurological functions and recurrent worsening of the symptoms.
Inhibition of ion transport ATPases by HNE
Authors: Crifò C. , Capuozzo E. , Siems W. , Salerno C.
Published: December 2008

4‐Hydroxy‐2,3‐trans‐nonenal (HNE), a major lipid peroxidation product, has been shown to react with specific amino acid residues of proteins and alter their function. In vitro exposure of erythrocyte ghosts and neutrophil membranes to HNE results in the inhibition of ion transport ATPases. Neutrophil membrane Ca2+‐ATPase is strongly inhibited by micromolar concentrations of HNE, while HNE is considerably less effective against neutrophil Mg2+‐ATPase and the erythrocyte ghost enzymes.
Cyto‐ and genotoxic potential of β‐carotene and cleavage products under oxidative stress
Authors: Alija A.J. , Bresgen N. , Sommerburg O. , Langhans C.D. , Siems W. , Eckl P.M.
Published: December 2008

Free radical attack on β‐carotene results in the formation of high amounts of cleavage products with prooxidant activities towards subcellular organelles such as mitochondria, a finding which could provide an explanation for the contradictory results obtained with β‐carotene in clinical efficacy and cancer prevention trials. Since primary hepatocytes proved to be very sensitive indicators for the genotoxic action of suspect mutagens/carcinogens we therefore investigated a β‐carotene cleavage products mixture (CP), apo‐8′‐β‐carotenal (apo‐8′) and β‐carotene in the primary rat hepatocyte assay in the presence and absence of oxidative stress provided by hypoxia/reoxygenation (Hy/re). The endpoints tested were: the mitotic indices, the percentages of necrotic and apoptotic cells, micronucleated cells (MN), chromosomal aberrations (CA) and sister chromatid exchanges (SCE). The results obtained indicate a genotoxic potential of both CP and apo‐8′ already in the concentration range of 100 nM and 1 μM, i.e. at physiologically relevant levels of β‐carotene and β‐carotene breakdown products. In contrast, no significant cytotoxic effects of these substances were observed, nor did β‐carotene induce significant cytotoxic or genotoxic effects at concentrations ranging from 0.01 up to 10 μM. However, when β‐carotene is supplemented during oxidative stress induced by hypoxia/reoxygenation, a dose‐dependent increase of CP is observed accompanied by increasing genotoxicity. Furthermore, when β‐carotene cleavage products were supplied during oxidative stress significant additional increases of genotoxic effects were observed, the additional increases indicating an additive effect of both exposures.

Summarizing, these results provide strong evidence that β‐carotene breakdown products are responsible for the occurrence of carcinogenic effects found in the Alpha‐Tocopherol Beta‐carotene‐Cancer prevention (ATBC) study and the beta‐CArotene and RETinol Efficacy (CARET) Trial.
Distribution of oxidized and HNE‐modified proteins in U87 cells
Authors: Jung Tobias , Engels Martina , Kaiser Barbara , Grune Tilman
Published: December 2008

Protein modification is one of the important processes during oxidative stress. This modification of proteins is either due to direct oxidation of proteins by various oxidants or due to secondary modification by lipid peroxidation products, e.g. 4‐hydroxynonenal. In the here presented work we compare the intracellular distribution of protein modification products after treatment of human U87 astrocytoma cells with hydrogen peroxide or HNE. The treatment with hydrogen peroxide leads mainly to a cytosolic formation of oxidized proteins whereas HNE treatment is forming HNE‐adducts throughout the cell.

Therefore, we concluded that HNE diffusion distance in cells enables this lipid peroxidation product to act as a second messenger within the cell and on the other hand is the reason for the genotoxic properties of this compound.
Iron regulatory protein 1 as a sensor of reactive oxygen species
Authors: Mueller Sebastian
Published: December 2008

Iron regulatory proteins (IRP1 and 2) function as translational regulators that coordinate the cellular iron metabolism of eukaryotes by binding to the mRNA of target genes such as the transferrin receptor or ferritin. In addition to IRP2, IRP1 serves as sensor of reactive oxygen species (ROS). As iron and oxygen are essential but potentially toxic constituents of most organisms, ROS‐mediated modulation of IRP1 activity may be an important regulatory element in dissecting iron homeostasis and oxidative stress. The responses of IRP1 towards reactive oxygen species are compartment‐specific and rather complex: H2O2 activates IRP1 via a signaling cascade that leads to upregulation of the transferrin receptor and cellular iron accumulation. Contrary, superoxide inactivates IRP1 by a direct chemical attack being limited to the intracellular compartment. In particular, activation of IRP1 by H2O2 has established a new regulatory link between inflammation and iron metabolism with new clinical implications. This mechanism seems to contribute to the anemia of chronic disease and inflammation‐mediated iron accumulation in tissues. In addition, the cytotoxic side effects of redox‐cycling anticancer drugs such as doxorubicin may involve H2O2‐mediated IRP1 activation. These molecular insights open up new therapeutic strategies for the clinical management of chronic inflammation and drug‐mediated cardiotoxicity.
Effect of carotenoid oxidation products on neutrophil viability and function
Authors: Salerno C. , Crifò C. , Capuozzo E. , Sommerburg O. , Langhans C.‐D. , Siems W.
Published: December 2008

Human neutrophils are short‐lived cells that play important roles in host defense and acute inflammation by releasing hydrolytic and cytotoxic proteins and reactive oxygen derivatives. Apoptosis, a physiological mechanism for cell death, regulates both production and survival of neutrophils, representing a basic biological mechanism for this type of cells. Carotenoids may react with toxic oxygen metabolites released by neutrophils to form a multitude of carotenoid cleavage products that exert, in turn, relevant prooxidative biological effects. Recent data suggest that carotenoid oxidation products may affect neutrophil viability and function by exerting proapoptotic activity and interfering with superoxide production by activated cells. The prooxidant and proapoptotic activities of carotenoid oxidation products could account, at least in some cases, for the procancerogenic properties of carotenoid rich diet.
Homocysteine induces DNA synthesis and proliferation of vascular smooth muscle cells by interfering with MAPK kinase pathway
Authors: Kartal Özer Nesrin , Taha Suzan , Azzi Angelo
Published: December 2008

Hyperhomocysteinemia has been identified as an important and independent risk factor for cerebral, coronary and peripheral atherosclerosis. However the mechanisms by which homocysteine promote atherosclerotic plaque formation are not clearly defined. Earlier reports have suggested that homocysteine exert its effect via the H2O2 produced during its metabolism. To evaluate which signalling molecules are involved in homocysteine induced atherosclerotic changes during the pathogenesis of vascular diseases, we examined homocysteine induced smooth muscle cell proliferation in the presence of different signal transduction inhibitors. We show that MAPK kinase pathway is involved in homocysteine induced DNA synthesis and proliferation of vascular smooth muscle cells in the presence of the peroxide scavenging enzyme, catalase. Our data suggest that homocysteine induces smooth muscle cell growth through a pathway that is independent of H2O2, that involves MAPK kinase activation, and that results in accelerated atherosclerosis.
F2‐Isoprostanes as biomarkers of lipid peroxidation in patients with chronic renal failure
Authors: Wiswedel Ingrid , Hirsch Daniela , Carluccio Francesco , And Hannelore Hampl , Siems Werner
Published: December 2008

Chronic renal failure patients on long‐term hemolysis are found to be under increased oxidative stress, caused by antioxidant deficiency, neutrophil activation during hemodialysis (HD), platelet activation and/or chronic inflammation. Increased levels of oxidants (e.g. malondialdehyde, 4‐hydroxynonenal, hydrocarbons, lipohydroperoxides, oxycholesterols, carbonyls) in HD patients are thought to play an important role in the development of endothelial dysfunction, atherogenesis and cardiovascular disease, which is a frequent condition in end‐stage renal disease. F2‐isoprostanes have been established as chemically stable, highly specific and reliable biomarkers of in vivo oxidative stress which can very sensitively measured by gas chromatography‐mass spectrometry (Morrow et al. [17]). An up to 6‐fold increase of plasma F2‐isoprostanes in HD patients is accompanied by an enhanced formation of indicators of inflammation (e.g. C‐reactive protein) and decreases of endogenous antioxidants (e.g. ascorbate, a‐tocopherol). In their esterified form F2‐isoprostanes may be a useful criteria to evaluate the effectiveness of clinical interventions to diminish oxidant stress and associated inflammation. Furthermore, F2‐isoprostanes possess potent biological activities (e.g. 8‐iso‐PGF2α; is known as a renal vasoconstrictor) suggesting that they may also act as mediators of the cellular effects of oxidative stress and inflammation.
Expression and synthesis of TGFβ1 is induced in macrophages by 9‐oxononanoyl cholesterol, a major cholesteryl ester oxidation product
Authors: Sottero Barbara , Gamba Paola , Longhi Monica , Robbesyn Fanny , Abuja Peter M. , Schaur Rudolf J. , Poli Giuseppe , Leonarduzzi Gabriella
Published: December 2008

Within the broad variety of compounds generated via oxidative reactions in low density lipoproteins (LDL) and subsequently found in the atherosclerotic plaque, are aldehydes still esterified to the parent lipid and termed core‐aldehydes. The most represented cholesterol core‐aldehyde in LDL is 9‐oxononanoyl cholesterol (9‐ONC), an oxidation product of cholesteryl linoleate. Here we report that 9‐ONC, at concentration actually detectable in biological material, significantly up‐regulates the expression and the synthesis of the pro‐fibrogenic cytokine transforming growth factor β1 (TGFβ1) by cultured macrophages. As previously demonstrated for other lipid oxidation products present in LDL, namely a biologically representative mixture of oxysterols and the unesterified aldehyde 4‐hydroxynonenal, these effects on TGFβ1 by 9‐ONC further points to LDL lipid oxidation as a powerful source of pro‐fibrogenic stimuli.
Possible involvement of 4‐hydroxynonenal in splenocyte regulated liver regeneration
Authors: Cipak Ana , Borovic Suzana , Scukanec‐Spoljar Mira , Kirac Iva , Zarkovic Neven
Published: December 2008

Liver regeneration is a complex, systemic process regulated by humoral and cellular mechanisms. Inflammatory response to the extensive tissue damage, as in partial hepatectomy, plays important role during regeneration. Hence, it is assumed that the spleen might play a role in systemic inflammatory response involved in liver regeneration. On the other hand, liver damage and consequential regeneration are often associated with oxidative stress and lipid peroxidation. One of the end products of lipid peroxidation, 4‐hydroxynonenal (HNE), is nowadays considered not only as a “second toxic messenger of free radicals“ but also as a growth‐regulating factor. We therefore studied in vitro interactions of the HNE‐treated murine liver cells and autologous spleen cells. The spleen cells supported recovery of liver cells from the HNE cytotoxicity although spleen cells themselves exerted cytotoxic effects against the proliferating liver cells that were not treated with HNE. Our results imply that the cytokines secreted by activated immunocompetent cells may be responsible for the observed recovery of the HNE‐damage liver cells, suggesting that HNE might be an important factor regulating cellular and cytokine mediated mechanisms of liver regeneration control.
Role of 4‐hydroxy‐2,3‐nonenal in the pathogenesis of fibrosis
Authors: Chiarpotto Elena , Castello Laura , Leonarduzzi Gabriella , Biasi Fiorella , Poli Giuseppe
Published: December 2008

Transient activation of fibroblasts or fibroblast‐like cells to proliferate and to produce elevated quantities of extracellular matrix is essential to fibrosis. This activation is regulated by several cytokines produced by various inflammation‐associated cells. Among these, transforming growth factor beta1 (TGFβ1) is considered of major importance. Many studies have shown that lipid peroxidation play a key role in the initiation and progression of fibrosis in different organs. In fact, 4‐hydroxy‐2,3‐nonenal (HNE), the major aldehydic product of lipid peroxidation, is able to induce TGFβ1 expression and synthesis, and activation of activator protein‐1 (AP‐1) transcription factor. In this study, using the murine macrophage line J774‐A1, we show that these effects are strictly related to the chemical structure of HNE, since neither 2‐nonenal nor nonanal are biologically active to the same extent. Moreover, we demonstrate that HNE can indeed contribute to the onset of fibrosis by stimulating AP‐1 binding to DNA and consequently inducing TGFβ1 expression, since thiol‐group reagents, such as N‐ethylmaleimide and 4‐(chloro‐mercuri)‐benzenesulfonic acid, that down‐modulate HNE entrance and localisation inside the cell, prevent both phenomena.

The possibility to control fibrogenic cytokine levels by means of antioxidant or dietetic treatments opens new potential pharmacological and nutritional horizons in the treatment of many chronic diseases characterised by excessive fibrosis.
4‐Hydroxynonenal and TGF‐β1 concur in inducing antiproliferative effects on the Caco‐2 human colon adenocarcinoma cell line
Authors: Vizio Barbara , Poli Giuseppe , Chiarpotto Elena , Biasi Fiorella
Published: December 2008

4‐Hydroxynonenal (HNE) has been demonstrated to exert its antiproliferative effect by up‐regulating the c‐Jun‐N‐terminal kinase (JNK), a member of the mitogen‐activated protein kinase family (MAPKs). Transforming growth factor‐β1 (TGF‐β1) is the major negative regulatory factor in controlling cell proliferation, and Smads are its intracellular transducers. Recent data on human colon adenocarcinoma has shown a low HNE content paralleled by a marked alteration of TGF‐β1 levels within the tumor mass. The two events appear related because of the demonstrated marked ability of HNE to up‐regulate expression and synthesis of TGF‐β1; the combined decreases of HNE and TGF‐β1 found in cancer cells provide a favorable condition for neoplastic progression. Furthermore, HNE is likely able to interact with the cytokine to enhance apoptosis and increase intracellular reactive oxygen species (ROS) formation in the Caco‐2 colon carcinoma cell line.

The probable mechanism whereby HNE and TGF‐β1 interact to induce apoptosis is through cross‐talk between the main signaling pathways of the two molecules (JNK and Smads), and the observed ROS production might only contribute to amplifying the apoptotic pathways. The network between the two signaling pathways here involved is now under investigation.
Iron uptake of the normoxic, anoxic and postanoxic microglial cell line RAW 264.7
Authors: Widmer Rebecca , Grune Tilman
Published: December 2008

Iron is one of the trace elements playing a key role in the normal brain metabolism. An excess of free iron on the other hand is catalyzing the iron‐mediated oxygen radical production. Such a condition might be a harmful event leading perhaps to serious tissue damage and degeneration. Therefore, during evolution a complex iron sequestering apparatus developed, minimizing the amount of redox‐reactive free iron. However, this system might be severely disturbed under pathophysiological conditions including hypoxia or anoxia.

Since little is known about the non‐transferrin‐mediated iron metabolism of the brain during anoxia/reoxygenation, we tested the ability of the microglial cell line RAW 264.7 to take up iron independently of transferrin under various oxygen concentrations. Microglial cells are thought to be the major player in the maintenance of the extracellular homeostasis in the brain. Therefore, we investigated the iron metabolism of microglial cells employing radiolabeled ferric chloride. We tested the uptake of iron under normoxic, anoxic and postanoxic conditions. Furthermore, the amount of ferritin was measured by immunoblotting. We were able to show that iron enters the microglial cell line in the absence of extracellular transferrin under normoxic, anoxic and postanoxic conditions. Interestingly, the amount of ferritin is decreasing in the early reoxygenation phase.

Therefore, we concluded that microglia is able to contribute to the brain iron homeostasis under anoxic and postanoxic conditions.
Copper related toxic effects on cellular protein metabolism in human astrocytes
Authors: Merker Katrin , Hapke Doreen , Reckzeh Kristian , Schmidt Hartmut , Lochs Herbert , Grune Tilman
Published: December 2008

Introduction: Copper overload due to a defect in the ATPase 7B mediated copper excretion within hepatocytes produces the phenotype of Wilson disease. The overload of hepatocytes with copper results in necrotic liver cells and is accompanied by a high concentration of blood copper levels. That occurs to be the reason for increasing neurological copper concentration. Although copper is linked to oxidation, there are no data on the direct copper related effects in human brain cells.

Aim: To test the copper induced changes in protein oxidation in human astrocyte like cells.

Methods: We used U87 cells as model for human astrocytes. Cells were treated with increasing concentrations of copper(II)‐chloride in Dulbeccos minimal essential medium. Subsequently, at different time points we investigated: cellular growth, cellular survival under copper treatment, the concentration of oxidized tryptophane in GADPH in vitro as well as the carbonyl concentration and the concentration of oxidized proteins in vivo in U87 glial cells.

Results: The viability of cells decreased with both increasing copper concentration and duration of treatment. The concentration of oxidized proteins was directly correlated to the increase of copper concentration and duration of exposure.

Conclusion: These observations demonstrate the similarities between copper treatment and treatment with other commonly used oxidants, including hydrogen peroxide. Furthermore, the vulnerability of astrocytes towards copper exposure could be demonstrated. Therefore, these data give further insights into understanding of copper metabolism, which in turn is important to reveal the exact pathological mechanism in copper related diseases such as Wilson disease.
Role of 4‐hydroxynonenal in the hemozoin‐mediated inhibition of differentiation of human monocytes to dendritic cells induced by GM‐CSF/IL‐4
Authors: Skorokhod Oleksii , Schwarzer Evelin , Grune Tilman , Arese Paolo
Published: December 2008

In falciparum malaria, rupture of parasitized RBC liberates hemozoin (HZ), polymerized heme that contains and generates lipoperoxidation products. In HZ and HZ‐loaded monocytes 4‐HNE attained approx. 50 and 15 μM, respectively. In malaria, HZ‐loaded monocytes are precursors of dendritic cells (DC). Here, the role of 4‐HNE as inhibitor of DC differentiation was examined. 4‐HNE in HZ was quantified after derivatization by HPLC. DC were differentiated in vitro from human monocytes supplemented with GM‐CSF/IL‐4 and analyzed for surface antigens and 4‐HNE‐adducts by FACScan after labelling with specific antibodies. HZ‐loading, or treatment with 4‐HNE induced large numbers of 4‐HNE‐protein‐adducts on the monocyte membrane. As low as 10 nM 4‐HNE inhibited up‐regulation of functionally important DC differentiation markers. 1 μM 4‐HNE elicited inhibition of up‐regulation of DC differentiation markers as follows: MHC‐class I and II, −29% and −40%; CD1a, −16%; CD40, −25%; CD54, −27%; and CD83 (the most important DC differentiation marker), −45%, with no signs of apoptosis. The sequence of additions was important, as the inhibitory effect was reduced when 4‐HNE was added after GM‐CSF/IL‐4, indicating that GM‐CSF/IL‐4 receptors could be modified by 4‐HNE. In conclusion, inhibition of DC differentiation by 4‐HNE may play a role in malaria immunodepression.
HNE‐dependent molecular damage in diabetic nephropathy and its possible prevention by N‐acetyl‐cysteine and oxerutin
Authors: Furfaro Anna Lisa , Menini Stefano , Patriarca Stefania , Pesce Carlo , Odetti Patrizio , Cottalasso Damiano , Marinari Umberto M. , Adelaide Pronzato M. , Traverso Nicola
Published: December 2008

Accumulation of Advanced Lipoxidation End‐products (ALE), such as MDA‐ and HNE‐protein adducts, and Advanced Glycation End‐products, such as carboxymethyl‐lysine (CML), are probably involved in the development of diabetic nephropathy. In this study the effect of some antioxidant treatments (oxerutin, N‐acetylcysteine, taurine and N‐acetylcysteine+taurine) on kidney lipoxidative damage has been evaluated by immunohistochemistry in streptozotocined rats.

Diabetic rats showed marked glomerular positivity for ALE, while the samples from Control rats were negative. All treatments except taurine were able to protect the glomeruli from ALE accumulation; the failure of taurine may be due to residual oxidative properties of its derivatives. These data are consistent with those of our previous study, which showed that all the antioxidants used except taurine protected the glomeruli from diabetes‐induced enlargement, increased apoptotic rate, decreased cell density and CML accumulation.

These data attest to a role of glycoxidative and lipoxidative damage in diabetes‐dependent damage of the kidney, and indicate that specific antioxidants can prevent or attenuate diabetic nephropathy.
Supercomplex organization of the mitochondrial respiratory chain and the role of the Coenzyme Q pool: Pathophysiological implications
Authors: Genova Maria Luisa , Bianchi Cristina , Lenaz Giorgio
Published: December 2008

In this review we examine early and recent evidence for an aggregated organization of the mitochondrial respiratory chain. Blue Native Electrophoresis suggests that in several types of mitochondria Complexes I, III and IV are aggregated as fixed supramolecular units having stoichiometric proportions of each individual complex. Kinetic evidence by flux control analysis agrees with this view, however the presence of Complex IV in bovine mitochondria cannot be demonstrated, presumably due to high levels of free Complex. Since most Coenzyme Q appears to be largely free in the lipid bilayer of the inner membrane, binding of Coenzyme Q molecules to the Complex I‐III aggregate is forced by its dissociation equilibrium; furthermore free Coenzyme Q is required for succinate‐supported respiration and reverse electron transfer. The advantage of the supercomplex organization is in a more efficient electron transfer by channelling of the redox intermediates and in the requirement of a supramolecular structure for the correct assembly of the individual complexes. Preliminary evidence suggests that dilution of the membrane proteins with extra phospholipids and lipid peroxidation may disrupt the supercomplex organization. This finding has pathophysiological implications, in view of the role of oxidative stress in the pathogenesis of many diseases.