4-hydroxy-2-nonenal and Nerve-Degeneration

Lipid peroxidation involves a cascade of reactions in which production of free radicals occurs selectively in the lipid components of cellular membranes. Polyunsaturated fatty acids easily undergo lipid peroxidation chain reactions, which, in turn, lead to the formation of highly reactive electrophilic aldehydes. Among these, the most abundant aldehydes are 4-hydroxy-2-nonenal (HNE) and malondialdehyde, while acrolein is the most reactive. Proteins are susceptible to posttranslational modifications caused by aldehydes binding covalently to specific amino acid residues, in a process called Michael adduction, and these types of protein adducts, if not efficiently removed, may be, and generally are, dangerous for cellular homeostasis. In the present review, we focused the discussion on the selective proteins that are identified, by redox proteomics, as selective targets of HNE modification during the progression and pathogenesis of Alzheimer disease (AD). By comparing results obtained at different stages of the AD, it may be possible to identify key biochemical pathways involved and ideally identify therapeutic targets to prevent, delay, or treat AD.

Topics: Aldehydes; Alzheimer Disease; Fatty Acids, Unsaturated; Gene Expression Regulation; Humans; Lipid Peroxidation; Malondialdehyde; Nerve Degeneration; Protein Processing, Post-Translational; Proteins

Phospholipase A2 (PLA2) generates arachidonic acid, docosahexaenoic acid, and lysophospholipids from neural membrane phospholipids. These metabolites have a variety of physiological effects by themselves and also are substrates for the synthesis of more potent lipid mediators such as eicosanoids, platelet activating factor, and 4-hydroxynonenal (4-HNE). At low concentrations, these mediators act as second messengers. They affect and modulate several cell functions, including signal transduction, gene expression, and cell proliferation, but at high concentrations, these lipid mediators cause neurotoxicity. Among the metabolites generated by PLA2, 4-HNE is the most cytotoxic metabolite and is associated with the apoptotic type of neural cell death. Levels of 4-HNE are markedly increased in neurological disorders such as Alzheimer disease, Parkinson disease, ischemia, spinal cord trauma, and head injury. The purpose of this review is to summarize and integrate the vast literature on metabolites generated by PLA2 for a wider audience. The authors hope that this discussion will jump-start more studies not only on the involvement of PLA2 in neurological disorders but also on the importance of PLA2-generated lipid mediators in physiological and pathological processes.

Topics: Aldehydes; Animals; Brain; Brain Diseases; Cytotoxins; Eicosanoids; Humans; Membrane Lipids; Nerve Degeneration; Neurons; Phospholipases A; Phospholipases A2; Phospholipids

Fibrillogenesis is a major feature of Alzheimer's disease (AD) and other neurodegenerative diseases. Fibers are correlated with disease severity and they have been implicated as playing a direct role in disease pathophysiology. In studies of tau, instead of finding causality with tau fibrils, we found that tau is associated with reduction of oxidative stress. Biochemical findings show that tau oxidative modifications are regulated by phosphorylation and that tau found in neurofibrillary tangles is oxidatively modified, suggesting that tau is closely linked to the biology, not toxicity, of AD.

Topics: Aldehydes; Alzheimer Disease; Animals; Guanosine; Humans; Mice; Nerve Degeneration; Neurofibrillary Tangles; Oxidative Stress; Phosphorylation; tau Proteins

Oxidative stress contributes to the cascade leading to dopamine cell degeneration in Parkinson's disease (PD). However, oxidative stress is intimately linked to other components of the degenerative process, such as mitochondrial dysfunction, excitotoxicity, nitric oxide toxicity and inflammation. It is therefore difficult to determine whether oxidative stress leads to, or is a consequence of, these events. Oxidative damage to lipids, proteins, and DNA occurs in PD, and toxic products of oxidative damage, such as 4-hydroxynonenal (HNE), can react with proteins to impair cell viability. There is convincing evidence for the involvement of nitric oxide that reacts with superoxide to produce peroxynitrite and ultimately hydroxyl radical production. Recently, altered ubiquitination and degradation of proteins have been implicated as key to dopaminergic cell death in PD. Oxidative stress can impair these processes directly, and products of oxidative damage, such as HNE, can damage the 26S proteasome. Furthermore, impairment of proteasomal function leads to free radical generation and oxidative stress. Oxidative stress occurs in idiopathic PD and products of oxidative damage interfere with cellular function, but these form only part of a cascade, and it is not possible to separate them from other events involved in dopaminergic cell death.

Topics: Aldehydes; Apoptosis; Corpus Striatum; Dopamine; Free Radicals; Glutathione Disulfide; Humans; Iron; Lipid Peroxidation; Mitochondria; Nerve Degeneration; Oxidation-Reduction; Oxidative Stress; Parkinson Disease; Peptide Hydrolases; Proteasome Endopeptidase Complex; Substantia Nigra; Superoxide Dismutase

Sodium vitamin C transporter 2 (SVCT2) plays a key role in transporting ascorbic acid (AA), an important intracellular antioxidant, into neurons. It is well known that ethanol (EtOH) abuse causes significant neurodegeneration, as well as endogenous AA release in certain encephalic regions. Here, we identified that SVCT2 forms part of a self-defense mechanism that protects against oxidative stress in binge drinking rats, and SVCT2 levels are correlated with antioxidants and neuronal injury. Four days of binge drinking led to massive neuron degeneration in prefrontal cortex (PFC), accompanied by increased levels of 4-hydroxynonenal (4-HNE)-adducted proteins and SVCT2 expression, as well as dramatic changes in AA levels in rat brain. AA levels were decreased in PFC and increased in cerebrospinal fluid (CSF) after binge drinking, but returned to normal on the 7th day following EtOH withdrawal. These processes were further evaluated in primary cortical neurons exposed to 100mM EtOH in vitro. Neurons transfected with SVCT2 siRNA were more susceptible than controls to certain aspects of EtOH-induced injury, including cell death, dendrite damage and increased oxidative stress. EtOH-induced up-regulation of SVCT2 was associated with activation of JNK and p38 MAPKs and the NF-κB pathway. More importantly, miRNA-125a-5p was down-regulated in PFC of 4-day binge drinking rats and negatively regulated protein expression during EtOH-induced neuronal injury. MiR-125a-5p over-expression attenuated intracellular AA levels, promoted cell death and suppressed the EtOH-induced up-regulation of p38 MAPK and SVCT2, which suggested that miR-125a-5p plays an important role in SVCT2 function in EtOH-induced neuronal injury. We speculate that SVCT2, possibly regulated by JNK/p38 MAPKs, NF-κB signaling and miR-125a-5p, has a neuroprotective effect against EtOH-induced oxidative stress. Promotion of SVCT2 expression or stimulation of SVCT2 activity may be a promising therapeutic strategy for the prevention of EtOH-associated neurodegeneration.

Topics: Aldehydes; Animals; Antioxidants; Ascorbic Acid; Binge Drinking; Dendrites; Ethanol; Gene Expression Regulation; Humans; MAP Kinase Kinase 4; MicroRNAs; Nerve Degeneration; Neurons; NF-kappa B; Oxidative Stress; p38 Mitogen-Activated Protein Kinases; Prefrontal Cortex; Rats; RNA, Small Interfering; Sodium-Coupled Vitamin C Transporters

Trimethyltin (TMT), an organotin compound considered a useful tool to obtain an experimental model of neurodegeneration, exhibits neurotoxicant effects selectively localised in the limbic system and especially in the hippocampus, which are different in the rat and in mice. In the rat hippocampus, we investigated the expression of aldehyde 4-hydroxynonenal, a major bioactive marker of membrane lipid peroxidation, heat shock protein (HSP) 110/105 family members, markers of oxidative stress, and the neuroinflammatory marker cyclooxygenase-2 after TMT-intoxication at various time points after treatment. Our data show that TMT-induced neurodegeneration in the rat hippocampus is associated specifically with oxidative stress and lipid peroxidation, but not with HSP expression, indicating species-specific differences in the neurotoxicity of TMT between rats and mice.

Topics: Aldehydes; Animals; Biomarkers; Cyclooxygenase 2; Cysteine Proteinase Inhibitors; Female; Hippocampus; HSP110 Heat-Shock Proteins; Mice; Nerve Degeneration; Rats; Rats, Wistar; Trimethyltin Compounds

The organotin trimethyltin (TMT) is well known to cause neuronal degeneration in the hippocampal dentate gyrus of mice. The first purpose of the present study was to examine whether the cyclooxygenase (COX) inhibitor indomethacin could ameliorate neuronal degeneration in the dentate gyrus of mice following TMT treatment in vivo. The systemic injection into mice of TMT at 2.8 mg/kg produced activation of endogenous caspase-3 and calpain, enhanced the gene expression of COX-1 and COX-2, activated microglial cells, and caused the formation of the lipid peroxidation product 4-hydroxynonenal in the hippocampus. Given at 12-h post-TMT treatment, the systemic injection of indomethacin (5 or 10 mg/kg, subcutaneously) significantly decreased the TMT-induced damage to neurons having active caspase-3 and single-stranded DNA in the dentate granule cell layer of the hippocampus. The results of the α-Fodrin degradation test revealed that the post-treatment with indomethacin was effective in attenuating TMT-induced activation of endogenous caspases and calpain in the hippocampus. In TMT-treated animals, interestingly, the post-treatment with indomethacin produced not only activation of microglial cells in the dentate gyrus but also the formation of 4-hydroxynonenal in the dentate granule cell layer. Taken together, our data suggest that COX inhibition by indomethacin ameliorated TMT-induced neuronal degeneration in the dentate gyrus by attenuating intensive oxidative stress.

Topics: Aldehydes; Animals; Caspase 3; Cyclooxygenase 1; Cyclooxygenase 2; Cyclooxygenase Inhibitors; Dentate Gyrus; Hippocampus; Indomethacin; Male; Mice; Microglia; Nerve Degeneration; Neuroprotective Agents; Oxidative Stress; Reverse Transcriptase Polymerase Chain Reaction; RNA, Messenger; Trimethyltin Compounds

Zinc dyshomeostasis may trigger oxidative stress, which is likely the key mechanism of neuronal death in amyotrophic lateral sclerosis (ALS), including familial forms such as G93A SOD-1 ALS. Since zinc binding by G93A SOD-1 is weaker than by normal SOD-1, we assessed whether labile zinc levels are altered in the spinal cords of G93A SOD-1 transgenic (Tg) mice. Whereas no zinc-containing cells were found in wild-type (WT) mice, neurons and astrocytes with high levels of labile zinc appeared in G93A SOD-1 Tg mice, in correlation with motoneuron degeneration. The level of HNE, an endogenous neurotoxic molecule, was increased around zinc-accumulating cells and mSOD-1 positive cells, suggesting a link between HNE, SOD-1 mutation and zinc accumulation. Moreover, exposure of cultured spinal neurons and astrocytes from G93A SOD-1 Tg mice to HNE increased labile zinc levels, and exposure to zinc increased 4-hydroxynonenal (HNE) levels, to a greater degree than in WT neurons and astrocytes. Administration of the zinc chelator TPEN extended survival in G93A SOD-1 Tg mice. These results indicate that zinc dyshomeostasis occurs in the spinal cords of Tg mice, and that this dyshomeostasis may contribute to motoneuron degeneration.

Topics: Aldehydes; Amyotrophic Lateral Sclerosis; Animals; Astrocytes; Chelating Agents; Disease Models, Animal; Homeostasis; Mice; Mice, Transgenic; Motor Neurons; Mutation; Nerve Degeneration; Oxidative Stress; Spinal Cord; Superoxide Dismutase; Superoxide Dismutase-1; Survival Rate; Up-Regulation; Zinc

Apolipoprotein D (apoD), a member of the lipocalin family of transporter proteins binds a number of small lipophilic molecules including arachidonic acid and cholesterol. Recent studies showed a protective function of mammalian apoD as well as its insect and plant homologs against oxidative stress. In this study we investigated the effect of direct addition of exogenous human apoD protein purified from breast cystic fluid to rat hippocampal slice cultures after excitotoxic injury induced by the glutamate analog kainate. ApoD at a concentration of 10 microg/ml partially prevented loss of MAP2 immunostaining and LDH release from injured hippocampal neurons after kainate injury. ApoD also attenuated the increase in oxidative products of arachidonic acid and cholesterol, F(2)-isoprostanes and 7-ketocholesterol, respectively, after kainate treatment. In view of the molecular structure of apoD which consists of an eight stranded beta barrel that forms a binding pocket for a number of small hydrophobic molecules, we propose that apoD promotes its neuroprotective effects by binding to arachidonic acid and cholesterol thus preventing their oxidation to neurotoxic products such as 4-hydroxynonenal (4-HNE) and 7-ketocholesterol.

Topics: Aldehydes; Animals; Apolipoproteins D; Arachidonic Acid; Binding Sites; Cholesterol; F2-Isoprostanes; Hippocampus; Kainic Acid; Ketocholesterols; L-Lactate Dehydrogenase; Microtubule-Associated Proteins; Nerve Degeneration; Neurons; Neurotoxins; Organ Culture Techniques; Oxidative Stress; Rats; Rats, Wistar

Streptozotocin (STZ) is a nitrosamine-related compound that causes Alzheimer's disease (AD)-type neurodegeneration with cognitive impairment, brain insulin resistance, and brain insulin deficiency. Nitrosamines and STZ mediate their adverse effects by causing DNA damage, oxidative stress, lipid peroxidation, pro-inflammatory cytokine activation, and cell death, all of which occur in AD. We tested the hypothesis that exposure to N-nitrosodiethylamine (NDEA), which is widely present in processed/preserved foods, causes AD-type molecular and biochemical abnormalities in central nervous system (CNS) neurons. NDEA treatment of cultured post-mitotic rat CNS neurons (48 h) produced dose-dependent impairments in ATP production and mitochondrial function, and increased levels of 8-hydroxy-2'-deoxyguanosine, 4-hydroxy-2-nonenal, phospho-tau, amyloid-beta protein precursor-amyloid-beta (A beta PP-A beta), and ubiquitin immunoreactivity. These effects were associated with decreased expression of insulin, insulin-like growth factor (IGF)-I, and IGF-II receptors, and choline acetyltransferase. Nitrosamine exposure causes neurodegeneration with a number of molecular and biochemical features of AD including impairments in energy metabolism, insulin/IGF signaling mechanisms, and acetylcholine homeostasis, together with increased levels of oxidative stress, DNA damage, and A beta PP-A beta immunoreactivity. These results suggest that environmental exposures and food contaminants may play critical roles in the pathogenesis of sporadic AD.

Topics: 8-Hydroxy-2'-Deoxyguanosine; Adenosine Triphosphate; Aldehydes; Alzheimer Disease; Amyloid beta-Peptides; Amyloid beta-Protein Precursor; Animals; Animals, Newborn; Cells, Cultured; Cerebellar Cortex; Choline O-Acetyltransferase; Deoxyguanosine; Diethylnitrosamine; DNA Damage; Dose-Response Relationship, Drug; Energy Metabolism; Enzyme-Linked Immunosorbent Assay; Insulin; Insulin-Like Growth Factor I; Mitochondria; Nerve Degeneration; Neurons; Oxidative Stress; Rats; Rats, Long-Evans; Receptor, IGF Type 2; Streptozocin; Ubiquitin

The innate immune system senses the invasion of pathogenic microorganisms and tissue injury through Toll-like receptors (TLR), a mechanism thought to be limited to immune cells. We recently found that neurons express several TLRs, and that the levels of TLR2 and TLR4 are increased in neurons in response to energy deprivation. Here we report that TLR4 expression increases in neurons when exposed to amyloid beta-peptide (Abeta1-42) or the lipid peroxidation product 4-hydroxynonenal (HNE). Neuronal apoptosis triggered by Abeta and HNE was mediated by jun N-terminal kinase (JNK); neurons from TLR4 mutant mice exhibited reduced JNK and caspase-3 activation and were protected against apoptosis induced by Abeta and HNE. Levels of TLR4 were decreased in inferior parietal cortex tissue specimens from end-stage AD patients compared to aged-matched control subjects, possibly as the result of loss of neurons expressing TLR4. Our findings suggest that TLR4 signaling increases the vulnerability of neurons to Abeta and oxidative stress in AD, and identify TLR4 as a potential therapeutic target for AD.

Topics: Aged; Aged, 80 and over; Aldehydes; Alzheimer Disease; Amyloid beta-Peptides; Animals; Apoptosis; Brain; Caspase 3; Female; Humans; JNK Mitogen-Activated Protein Kinases; Lipid Peroxidation; Male; Membrane Lipids; Mice; Mice, Knockout; Nerve Degeneration; Oxidative Stress; Peptide Fragments; Signal Transduction; Toll-Like Receptor 4

Alzheimer's disease (AD) is associated with brain insulin resistance and insulin deficiency, whereas Type 2 diabetes mellitus (T2DM) is associated with peripheral insulin resistance. This study assesses the degree to which T2DM causes AD-type neurodegeneration. In a C57BL/6 mouse model of obesity and T2DM, we characterized the histopathology, gene expression, and insulin and insulin-like growth factor (IGF)-receptor binding in temporal lobe. High fat diet (HFD) feeding for 16 weeks doubled mean body weight, caused T2DM, and marginally reduced mean brain weight. These effects were associated with significantly increased levels of tau, IGF-I receptor, insulin receptor substrate-1 (IRS-1), IRS-4, ubiquitin, glial fibrillary acidic protein, and 4-hydroxynonenol, and decreased expression of beta-actin. HFD feeding also caused brain insulin resistance manifested by reduced BMAX for insulin receptor binding, and modestly increased brain insulin gene expression. However, HFD-fed mouse brains did not exhibit AD histopathology, increases in amyloid-beta or phospho-tau, or impairments in IGF signaling or acetylcholine homeostasis. Obesity and T2DM cause brain atrophy with insulin resistance, oxidative stress, and cytoskeleton degradation, but the absence of many features that typify AD suggests that obesity and T2DM may contribute to, but are not sufficient to cause AD.

Topics: Actins; Adaptor Proteins, Signal Transducing; Aldehydes; Alzheimer Disease; Amyloid beta-Peptides; Animals; Atrophy; Brain; Diabetes Mellitus, Type 2; DNA Primers; Enzyme-Linked Immunosorbent Assay; Gene Expression; Glial Fibrillary Acidic Protein; Insulin Receptor Substrate Proteins; Insulin Resistance; Insulin-Like Growth Factor I; Mice; Mice, Inbred C57BL; Nerve Degeneration; Obesity; Reverse Transcriptase Polymerase Chain Reaction; RNA, Messenger; Ubiquitin

Dentatorubral-pallidoluysian atrophy (DRPLA) is one of the CAG-repeat diseases, and is classified into juvenile and early adult types showing progressive myoclonus epilepsy (PME) in addition to late adult type. We immunohistochemically examined accumulation of oxidative products and expression of superoxide dismutase (SOD) in autopsy cases of DRPLA. Oxidative products to nucleosides, 8-hydroxy-2'-deoxyguanosine and 8-hydroxyguanosine, were accumulated in the lenticulate nucleus predominantly in DRPLA cases having PME. Neuronal accumulation of 4-hydroxy nonenal, a reactive lipid aldehyde, was found in the hippocampus, globus pallidus and cerebellar dentate nucleus in adult DRPLA cases and controls. Cytoplasmic immunoreactivity for Cu/ZnSOD was reduced in the external segment of globus pallidus, dentate nucleus and cerebellar cortex in DRPLA cases. Mitochondrial immunoreactivity for MnSOD was reduced in the lenticulate nucleus and cerebellum in DRPLA cases having PME. Some DRPLA cases showed reduced immunoreactivity for MnSOD in the cerebral cortex. Coexistence of reduced SOD expression and polyglutamine was observed in a few cases. It has been discussed in Huntington's disease that expanded polyglutamine can lead to oxidative neurodegeneration. It is likely that oxidative stress can be involved in DRPLA, although relationship with expanded polyglutamine remains to be elusive.

Topics: 8-Hydroxy-2'-Deoxyguanosine; Adult; Aged; Aldehydes; Autopsy; Biomarkers; Brain; Cytoplasm; Deoxyguanosine; Female; Guanosine; Humans; Immunohistochemistry; Male; Middle Aged; Mitochondria; Myoclonic Epilepsies, Progressive; Nerve Degeneration; Neurons; Oxidative Stress; Peptides; Superoxide Dismutase

Evidence suggests oxidative and electrophilic stress as a major factor contributing to the neuronal cell death in neurodegenerative disorders, especially Parkinson's disease. Consistent with this concept, administration of exogenous antioxidants has been shown to be protective against oxidative/electrophilic neurodegeneration. However, whether induction of endogenous antioxidants and phase 2 enzymes by the unique chemoprotectant, 3H-1,2-dithiole-3-thione (D3T) in neuronal cells also affords protection against oxidative and electrophilic neurocytotoxicity has not been carefully investigated. In this study, we showed that incubation of SH-SY5Y neuroblastoma cells or primary human neurons with micromolar concentrations (10-100 microM) of D3T for 24 h resulted in significant increases in the levels of reduced glutathione (GSH) and NAD(P)H:quinone oxidoreductase 1 (NQO1), two crucial cellular defenses against oxidative and electrophilic stress. D3T treatment also caused increases in mRNA expression of gamma-glutamylcysteine ligase catalytic subunit and NQO1 in SH-SY5Y cells. In addition, D3T treatment of the neuronal cells also resulted in a marked elevation of GSH content in the mitochondrial compartment. To determine the protective effects of the D3T-induced cellular defenses on neurotoxicant-elicited cell injury, SH-SY5Y cells were pretreated with D3T for 24 h and then exposed to dopamine, 6-hydroxydopamine (6-OHDA), 4-hydroxy-2-nonenal (HNE), or H2O2, agents that are known to be involved in neuron degeneration. We observed that D3T-pretreatment of SH-SY5Y cells led to significant protection against the cytotoxicity elicited by the above neurotoxicants. Similar neurocytoprotective effects of D3T-pretreatment were also observed in primary human neurons exposed to 6-OHDA or HNE. Taken together, this study demonstrates that D3T potently induces neuronal cellular GSH and NQO1 as well as mitochondrial GSH, and that such upregulated endogenous defenses are accompanied by increased resistance to oxidative and electrophilic neurocytotoxicity.

Topics: Aldehydes; Antioxidants; Cell Line, Tumor; Cells, Cultured; Dopamine; Glutathione; Humans; Hydrogen Peroxide; Mitochondria; NAD(P)H Dehydrogenase (Quinone); Nerve Degeneration; Neurons; Neuroprotective Agents; Oxidative Stress; Oxidopamine; Reverse Transcriptase Polymerase Chain Reaction; RNA, Messenger; Thiones; Thiophenes

There is growing evidence that free radical generation may play a key role in the neuronal damage induced by prolonged convulsions. Free radical scavengers are known to inhibit neuronal death induced by exposure to excitotoxins. However, this neuroprotective effect has not been demonstrated with treatment after seizures had been stopped. We investigated whether 3-methyl-1-phenyl-2-pyrazolin-5-one, edaravone (Ed), a newly developed free radical scavenger that has been used clinically to treat cerebral infarction, could prevent neuronal loss when administered after the occurrence of seizures in a kainic acid (KA)-induced seizure model. Compared with KA alone, cell loss was significantly reduced when animals received Ed (10 mg/kg i.v.) just after seizures, and when Ed was administered both 60 min before (30 mg/kg i.p.) and after KA injection. Combined before-and-after treatment with Ed significantly ameliorated the KA-induced decrease of glutathione and blocked the KA-induced increase of 4-hydroxy-2-nonenal (HNE). Because before-and-after treatment with Ed significantly lessened the KA-induced increase of HNE, Ed may exert its neuroprotective effect by inhibiting lipid peroxidation. However, post-treatment with Ed prevented neuronal cell loss, while HNE and glutathione levels did not differ from those in animals without Ed, so a mechanism other than free radical scavenging must be involved in the prevention of cell loss. Patients who develop status epilepticus are unlikely to receive adequate antioxidant therapy before the onset, so it is an advantage that Ed can prevent neuronal death even when administered after seizures.

Topics: Aldehydes; Animals; Antipyrine; Brain; Cell Death; Disease Models, Animal; Down-Regulation; Edaravone; Epilepsy; Free Radical Scavengers; Glutathione; Kainic Acid; Lipid Peroxidation; Male; Nerve Degeneration; Neurons; Neuroprotective Agents; Neurotoxins; Oxidative Stress; Rats; Rats, Sprague-Dawley; Status Epilepticus; Treatment Outcome

The mammalian inner ear loses its sensory cells with advancing age, accompanied by a functional decrease in balance and hearing. This study investigates oxidant stress in the cochlea of aging male CBA/J mice. Glutathione-conjugated proteins, markers of H2O2-mediated oxidation, began to increase at 12 months of age; 4-hydroxynonenal and 3-nitrotyrosine, products of hydroxyl radical and peroxynitrite action, respectively, were elevated by 18 months. Immunoreactivity to these markers was stronger in the supporting cells (Deiters and pillar cells) than the sensory cells and appeared later (23 months) in spiral ganglion cells and in the stria vascularis and spiral ligament. Conversely, antioxidant proteins (AIF) and enzymes (SOD2) decreased by 18 months in the organ of Corti (including the sensory cells) and spiral ganglion cells but not in the stria vascularis. These results suggest the presence of different reactive oxygen species and differential time courses of oxidative changes in individual tissues of the aging cochlea. An imbalance of redox status may be a component of age-related hearing loss.

Topics: Aging; Aldehydes; Animals; Apoptosis Inducing Factor; Biomarkers; Cochlea; Free Radicals; Hair Cells, Auditory; Male; Mice; Mice, Inbred CBA; Nerve Degeneration; Neurons, Afferent; Organ of Corti; Oxidative Stress; Spiral Ganglion; Superoxide Dismutase; Tyrosine

Peroxynitrite (PON, ONOO(-)), formed by nitric oxide synthase-generated nitric oxide radical ( NO) and superoxide radical (O(2) (-)), is a crucial player in post-traumatic oxidative damage. In the present study, we determined the spatial and temporal characteristics of PON-derived oxidative damage after a moderate contusion injury in rats. Our results showed that 3-nitrotyrosine (3-NT), a specific marker for PON, rapidly accumulated at early time points (1 and 3 h) and a significant increase compared with sham rats was sustained to 1 week after injury. Additionally, there was a coincident and maintained increase in the levels of protein oxidation-related protein carbonyl and lipid peroxidation-derived 4-hydroxynonenal (4-HNE). The peak increases of 3-NT and 4-HNE were observed at 24 h post-injury. In our immunohistochemical results, the co-localization of 3-NT and 4-HNE results indicates that PON is involved in lipid peroxidative as well as protein nitrative damage. One of the consequences of oxidative damage is an exacerbation of intracellular calcium overload, which activates the cysteine protease calpain leading to the degradation of several cellular targets including cytoskeletal protein (alpha-spectrin). Western blot analysis of alpha-spectrin breakdown products showed that the 145-kDa fragments of alpha-spectrin, which are specifically generated by calpain, were significantly increased as soon as 1 h following injury although the peak increase did not occur until 72 h post-injury. The later activation of calpain is most likely linked to PON-mediated secondary oxidative impairment of calcium homeostasis. Scavengers of PON, or its derived free radical species, may provide an improved antioxidant neuroprotective approach for the treatment of post-traumatic oxidative damage in the injured spinal cord.

Topics: Aldehydes; Animals; Biomarkers; Calcium Signaling; Calpain; Disease Progression; Female; Free Radical Scavengers; Free Radicals; Lipid Peroxidation; Nerve Degeneration; Nitric Oxide; Oxidative Stress; Peptide Fragments; Peroxynitrous Acid; Rats; Rats, Sprague-Dawley; Spectrin; Spinal Cord Injuries; Time Factors; Tyrosine; Up-Regulation

We assessed the temporal and spatial characteristics of PN-induced oxidative damage and its relationship to calpain-mediated cytoskeletal degradation and neurodegeneration in a severe unilateral controlled cortical impact (CCI) traumatic brain injury (TBI) model. Quantitative temporal time course studies were performed to measure two oxidative damage markers: 3-nitrotyrosine (3NT) and 4-hydroxynonenal (4HNE) at 30 min, 1, 3, 6, 12, 24, 48, 72 h and 7 days after injury in ipsilateral cortex of young adult male CF-1 mice. Secondly, the time course of Ca(++)-activated, calpain-mediated proteolysis was also analyzed using quantitative western-blot measurement of breakdown products of the cytoskeletal protein alpha-spectrin. Finally, the time course of neurodegeneration was examined using de Olmos silver staining. Both oxidative damage markers increased in cortical tissue immediately after injury (30 min) and elevated for the first 3-6 h before returning to baseline. In the immunostaining study, the PN-selective marker, 3NT, and the lipid peroxidation marker, 4HNE, were intense and overlapping in the injured cortical tissue. alpha-Spectrin breakdown products, which were used as biomarker for calpain-mediated cytoskeletal degradation, were also increased after injury, but the time course lagged behind the peak of oxidative damage and did not reach its maximum until 24 h post-injury. In turn, cytoskeletal degradation preceded the peak of neurodegeneration which occurred at 48 h post-injury. These studies have led us to the hypothesis that PN-mediated oxidative damage is an early event that contributes to a compromise of Ca(++) homeostatic mechanisms which causes a massive Ca(++) overload and calpain activation which is a final common pathway that results in post-traumatic neurodegeneration.

Topics: Aldehydes; Animals; Brain; Brain Injuries; Calcium; Calpain; Cerebral Cortex; Cytoskeleton; Lipid Peroxidation; Male; Mice; Mice, Inbred Strains; Nerve Degeneration; Nerve Tissue Proteins; Nitrates; Oxidative Stress; Peroxynitrous Acid; Spectrin; Time Factors; Tissue Distribution; Tyrosine

Considerable evidence supports the role of oxidative stress in the pathogenesis of Alzheimer's disease. One hallmark of Alzheimer's disease is the accumulation of amyloid beta-peptide, which invokes a cascade of oxidative damage to neurons that can eventually result in neuronal death. Amyloid beta-peptide is the main component of senile plaques and generates free radicals ultimately leading to neuronal damage of membrane lipids, proteins and nucleic acids. Therefore, interest in the protective role of different antioxidant compounds has been growing for treatment of Alzheimer's disease and other oxidative stress-related disorders. Among different antioxidant drugs, much interest has been devoted to "thiol-delivering" compounds. Tricyclodecan-9-yl-xanthogenate is an inhibitor of phosphatidylcholine specific phospholipase C, and recent studies reported its ability to act as a glutathione-mimetic compound. In the present study, we investigate the in vivo ability of tricyclodecan-9-yl-xanthogenate to protect synaptosomes against amyloid beta-peptide-induced oxidative stress. Gerbils were injected i.p. with tricyclodecan-9-yl-xanthogenate or with saline solution, and synaptosomes were isolated from the brain. Synaptosomal preparations isolated from tricyclodecan-9-yl-xanthogenate injected gerbils and treated ex vivo with amyloid beta-peptide (1-42) showed a significant decrease of oxidative stress parameters: reactive oxygen species levels, protein oxidation (protein carbonyl and 3-nitrotyrosine levels) and lipid peroxidation (4-hydroxy-2-nonenal levels). Our results are consistent with the hypothesis that modulation of free radicals generated by amyloid beta-peptide might represent an efficient therapeutic strategy for treatment of Alzheimer's disease and other oxidative-stress related disorders. Based on the above data, we suggest that tricyclodecan-9-yl-xanthogenate is a potent antioxidant and could be of importance for the treatment of Alzheimer's disease and other oxidative stress-related disorders.

Topics: Aldehydes; Alzheimer Disease; Amyloid beta-Peptides; Animals; Antioxidants; Brain; Bridged-Ring Compounds; Disease Models, Animal; Free Radicals; Gerbillinae; Lipid Peroxidation; Male; Nerve Degeneration; Neurons; Norbornanes; Oxidative Stress; Peptide Fragments; Reactive Oxygen Species; Synaptosomes; Thiocarbamates; Thiones; Type C Phospholipases; Tyrosine

In the last decade an important role for the progression of neuronal cell death in Alzheimer's disease (AD) has been ascribed to oxidative stress. trans-4-Hydroxy-2-nonenal, a product of lipid peroxidation, forms conjugates with a variety of nucleophilic groups such as thiols or amino moieties. Here we report for the first time the quantitation of glutathione conjugates of trans-4-hydroxy-2-nonenal (HNEGSH) in the human postmortem brain using the specific and very sensitive method of electrospray ionization triple quadrupole mass spectrometry (ESI-MS-MS). Levels of HNEGSH conjugates calculated as the sum of three chromatographically separated diastereomers were determined in hippocampus, entorhinal cortex, substantia innominata, frontal and temporal cortex, as well as cerebellum from patients with AD and controls matched for age, gender, postmortem delay and storage time. Neither age, nor postmortem delay, nor storage time did correlate with levels of HNEGSH conjugates which ranged between 1 and 500 pmol/g fresh weight in the brain areas examined. The brain specimen from patients with clinically and neuropathologically probable AD diagnosed according to criteria of the consortium to establish a registry for AD (CERAD) show increased levels of HNEGSH in the temporal and frontal cortex, as well as in the substantia innominata. Classification of disease severity according to Braak and Braak, which takes into consideration the amount of neurofibrillary tangles and neuritic plaques, revealed highest levels of HNEGSH in the substantia innominata and the hippocampus, two brain regions known to be preferentially affected in AD. These results substantiate the link between conjugates of glutathione with a product of lipid peroxidation and Alzheimer's disease and justify further studies to evaluate the role of HNE metabolites as potential biomarkers for disease progression in AD.

Topics: Age Factors; Aged; Aged, 80 and over; Aldehydes; Alzheimer Disease; Brain; Female; Glutathione; Hippocampus; Humans; Lipid Peroxidation; Male; Mass Spectrometry; Nerve Degeneration; Neurofibrillary Tangles; Neurons; Oxidative Stress; Plaque, Amyloid; Substantia Innominata; Substantia Nigra; Up-Regulation

Lipid membrane peroxidation is highly associated with neuronal death in various neurodegenerative diseases including cerebral stroke. Here, we report that simvastatin decreases oxygen and glucose deprivation (OGD)/reoxygenation-evoked neuronal death by inhibiting the production and cytoxicity of 4-hydroxy-2E-nonenal (HNE), the final product of lipid peroxidation. Simvastatin markedly decreased the OGD/reoxygenation-evoked death of cortical neurons. OGD/reoxygenation increased the intracellular HNE level mostly in neuronal cells, not glial cells. Simvastatin decreased the intracellular level of HNE in neuronal cells exposed to OGD/reoxygenation. We further found that HNE induced the cytotoxicity in neuronal cells and synergistically increased the N-methyl-D-aspartate (NMDA) receptor-mediated excitotoxicity. Simvastatin largely blocked the NMDA neurotoxicity potentiated by HNE. However, simvastatin did not alter the NMDA-evoked calcium influx in the absence or presence of HNE. HNE inhibited the activity of nuclear factor-kappa B (NF-kappaB), and the cytotoxicity of HNE was in good correlation with inactivation of NF-kappaB. Simvastatin reversed the inhibition of NF-kappaB activity induced by OGD/reoxygenation or HNE. The neuroprotection by simvastatin was significantly attenuated by various NF-kappaB inhibitors, implying that simvastatin inhibits the cytotoxicity of HNE at least in part by maintaining the activity of NF-kappaB. Further understanding of the neuroprotective mechanism of simvastatin may provide a therapeutic strategy for oxidative stress-related neurodegenerative diseases.

Topics: Aldehydes; Animals; Cell Death; Cells, Cultured; Cerebral Cortex; Cytoprotection; Enzyme Inhibitors; Hydroxymethylglutaryl-CoA Reductase Inhibitors; Hypoxia-Ischemia, Brain; Lipid Peroxidation; Nerve Degeneration; Neurons; Neuroprotective Agents; Neurotoxins; NF-kappa B; Oxidative Stress; Rats; Rats, Sprague-Dawley; Receptors, N-Methyl-D-Aspartate; Simvastatin

Increased production of reactive oxygen species (ROS) following cerebral ischemia-reperfusion (I/R) is an important underlying cause for neuronal injury leading to delayed neuronal death (DND). In this study, apocynin, a specific inhibitor for NADPH oxidase, was used to test whether suppression of ROS by the NADPH oxidase inhibitor can protect against ischemia-induced ROS generation and decrease DND. Global cerebral ischemia was induced in gerbils by a 5-min occlusion of bilateral common carotid arteries (CCA). Using measurement of 4-hydroxy-2-nonenal (HNE) as a marker for lipid peroxidation, apocynin (5 mg/kg body weight) injected i.p. 30 min prior to ischemia significantly attenuated the early increase in HNE in hippocampus measured at 3 h after I/R. Apocynin also protected against I/R-induced neuronal degeneration and DND, oxidative DNA damage, and glial cell activation. Taken together, the neuroprotective effects of apocynin against ROS production during early phase of I/R and subsequent I/R-induced neuronal damage provide strong evidence that inhibition of NADPH oxidase could be a promising therapeutic mechanism to protect against stroke damage in the brain.

Topics: Acetophenones; Aldehydes; Animals; Antioxidants; Biomarkers; Brain Ischemia; Cell Death; Cerebral Infarction; Disease Models, Animal; DNA Damage; Enzyme Inhibitors; Gerbillinae; Gliosis; Hippocampus; Male; NADPH Oxidases; Nerve Degeneration; Neurons; Neuroprotective Agents; Oxidative Stress; Reactive Oxygen Species; Reperfusion Injury; Time Factors; Treatment Outcome

4-hydroxynonenal (HNE), an aldehydic product of membrane lipid peroxidation, has been shown to induce neurotoxicity accompanied by multiple events. To clarify mechanisms of neuroprotective compounds on HNE-induced toxicity, the protective effects of N-acetylcysteine (NAC), alpha-tocopherol (TOC), ebselen and S-allyl-L-cysteine (SAC) were compared in cerebellar granule neurons. The decrease in MTT reduction induced by HNE was significantly suppressed by pretreatment of the neurons with 1000 microM NAC or 10 and 100 microM TOC; however, lactate dehydrogenase (LDH) release and propidium iodide (PI) fluorescence studies revealed that neuronal death was suppressed by NAC but not by TOC. Treatment of these neurons with HNE resulted in a drastic reduction of mitochondrial membrane potential, and this reduction was also prevented by NAC but not by TOC. Ebselen and SAC, a garlic compound, were unable to protect these neurons against HNE-induced toxicity. Pretreatment with NAC also prevented HNE-induced depletion of intracellular glutathione (GSH) levels in these neurons. These results suggest that NAC, but not other antioxidants such as TOC, SAC and ebselen, exerts significant protective effects against HNE-induced neuronal death in cerebellar granule neurons, and that this neuroprotective effect is due, at least in part, to preservation of mitochondrial membrane potential and intracellular GSH levels.

Topics: Acetylcysteine; Aldehydes; Animals; Animals, Newborn; Antioxidants; Brain; Cell Death; Cells, Cultured; Cerebellum; Free Radical Scavengers; Glutathione; L-Lactate Dehydrogenase; Mitochondrial Membranes; Nerve Degeneration; Neurodegenerative Diseases; Neurons; Neuroprotective Agents; Neurotoxins; Oxidative Stress; Plant Extracts; Rats; Rats, Wistar

The vulnerability of different dopaminergic cell populations to damage caused by the herbicide paraquat was assessed by stereological counts of tyrosine hydroxylase-positive and calbindin-D28k-immunoreactive neurons in A9 (substantia nigra pars compacta) and A10 (ventral tegmental area and other cell groups). In saline-treated control mice, tyrosine hydroxylase-immunoreactive neurons represented 80% and 45% of the total neuronal population in A9 and A10, respectively, and the number of calbindin-D28k-positive neurons was five times greater in A10 than A9. Sequential injections with paraquat resulted in a significant loss of dopaminergic neurons in A9. In contrast, tyrosine hydroxylase-positive cells in A10 were spared from paraquat-induced degeneration. Furthermore, expression of calbindin-D28k was consistently associated with neuronal resistance to the herbicide in both A9 and A10. Paraquat exposure also induced oxidative stress as indicated by an increase in the number of midbrain cells positive for 4-hydroxy-2-nonenal, a marker of lipid peroxidation. Co-localization studies revealed that calbindin-D28k immunoreactivity overlapped with tyrosine hydroxylase labeling and that, after paraquat administration, (i) the vast majority of midbrain 4-hydroxy-2-nonenal-immunoreactive cells were dopaminergic (tyrosine hydroxylase-immunoreactive), (ii) tyrosine hydroxylase/4-hydroxy-2-nonenal-positive neurons were much more prevalent in A9 than A10, and (iii) all calbindin-D28k-containing neurons were characterized by lack of lipid peroxidation (4-hydroxy-2-nonenal immunoreactivity). Results in this paraquat model emphasize that, despite sharing a similar dopaminergic phenotype, different groups of midbrain neurons vary dramatically in their vulnerability to injury. Data also indicate that these differences are attributable, at least in part, to a varying susceptibility of dopaminergic cell populations to oxidative stress.

Topics: Aldehydes; Analysis of Variance; Animals; Calbindin 1; Calbindins; Cell Count; Dopamine; Herbicides; Immunohistochemistry; Male; Mesencephalon; Mice; Nerve Degeneration; Neurons; Oxidative Stress; Paraquat; S100 Calcium Binding Protein G; Time Factors; Tyrosine 3-Monooxygenase

PTEN is a dual phosphatase that negatively regulates the phosphatidylinositol 3-kinase (PI3K)/Akt signalling pathway important for cell survival. We determined effects of the inflammation and oxidative stresses of tumor necrosis factor-alpha (TNFalpha) and trans-4-hydroxy-2-nonenal (HNE), respectively, on PTEN, Akt, and GSK3beta signalling in rat primary cortical neurons. The inhibitors bisperoxovanadium [bpV(Pic)] and LY294002 were also used to determine PTEN and PI3K involvement in TNFalpha and HNE modulation of neuronal cell death. PTEN inhibition with bpV(Pic) alone did not affect Ser(473)Akt or Ser(9)GSK3beta phosphorylation. Instead, effects of this inhibitor were manifest when it was used together with TNFalpha and to a lesser extent with HNE. TNFalpha together with PTEN inhibition increased phosphorylation of Ser(473)Akt and Ser(9)GSK3beta. TNFalpha and HNE both gave decreased numbers of viable and increased numbers of early apoptotic neurons. PTEN inhibition partially reversed the toxic effect of TNFalpha as shown by an increased number of viable and a decreased number of early apoptotic neurons. All effects were reversed by PI3K inhibition. HNE together with inhibition of PTEN gave increased Ser(473)Akt but not Ser(9)GSK3beta phosphorylation and no effects on the number of viable or early apoptotic cells. In conclusion, PTEN inhibition gives a mild reversal of TNFalpha- but not HNE-induced cell death via the PI3K pathway.

Topics: Aldehydes; Animals; Apoptosis; Cell Survival; Cells, Cultured; Cerebral Cortex; Cysteine Proteinase Inhibitors; Encephalitis; Enzyme Inhibitors; Glycogen Synthase Kinase 3; Glycogen Synthase Kinase 3 beta; Nerve Degeneration; Neurons; Phosphatidylinositol 3-Kinases; Phosphoinositide-3 Kinase Inhibitors; Phosphorylation; Proto-Oncogene Proteins c-akt; PTEN Phosphohydrolase; Rats; Rats, Sprague-Dawley; Serine; Signal Transduction; Tumor Necrosis Factor-alpha

Numerous studies demonstrate oestrogen's neuroprotective effect in stroke models, although the mechanisms are unclear. Since oestrogen is an antioxidant, we tested the hypothesis that oestrogen reduces stroke-induced damage by reducing free radical damage, particularly lipid peroxidation.. Sprague-Dawley rats were ovariectomised and a 17beta-oestradiol (0.25 mg, 21 day release) or placebo pellet implanted subcutaneously. Two weeks later, permanent middle cerebral artery occlusion (MCAO) was induced by intraluminal filament. At 2 and 24 h post-MCAO, neurological deficits were assessed. At the 24 h end point, plasma oestradiol was measured and brain sections stained with haematoxylin and eosin or lipid peroxidation marker, 4-hydroxynonenol (4-HNE) immunohistochemistry carried out to measure infarct volume and volume of tissue displaying oxidative damage, respectively.. Plasma 17beta-oestradiol in oestradiol and placebo groups was 72.6+/-38.0 and 9.3+/-7.4 pg/ml (mean+/-SD), respectively. Infarct volume was significantly increased (118%) with oestradiol treatment (oestradiol=124+/-84.5, placebo=57+/-46.4 mm3, mean+/-SD, P<0.05). The relationship between 4-HNE and infarct volume was significantly influenced by 17beta-oestradiol. Neurological deficits were similar between groups (oestradiol median=13, placebo=14, max score=33).. Two week pre-treatment with a high physiological dose of 17beta-oestradiol increased infarct volume after permanent MCAO. Although contrary to our original hypothesis, this result demonstrates that oestrogen does have the capacity to promote detrimental actions in the stroke-injured brain. Given the wide use of oestrogen (contraception, osteoporosis and menopause), more research to clarify the influence of oestrogen on brain injury is urgently required.

Topics: Aldehydes; Animals; Antioxidants; Brain Ischemia; Cerebral Cortex; Cerebral Infarction; Disease Models, Animal; Disease Progression; Drug Implants; Estradiol; Female; Infarction, Middle Cerebral Artery; Lipid Peroxidation; Nerve Degeneration; Neurologic Examination; Ovariectomy; Oxidative Stress; Rats; Rats, Sprague-Dawley; Up-Regulation

Retinitis pigmentosa (RP) is a prevalent cause of blindness caused by a large number of different mutations in many different genes. The mutations result in rod photoreceptor cell death, but it is unknown why cones die. In this study, we tested the hypothesis that cones die from oxidative damage by performing immunohistochemical staining for biomarkers of oxidative damage in a transgenic pig model of RP. The presence of acrolein- and 4-hydroxynonenal-adducts on proteins is a specific indicator that lipid peroxidation has occurred, and there was strong immunofluorescent staining for both in cone inner segments (IS) of two 10-month-old transgenic pigs in which almost all rods had died, compared to faint staining in two 10-month-old control pig retinas. In 22- and 24-month-old transgenic pigs in which all rods and many cones had died, staining was strong in cone axons and some cell bodies as well as IS indicating progression in oxidative damage between 10 and 22 months. Biomarkers for oxidative damage to proteins and DNA also showed progressive oxidative damage to those macromolecules in cones during the course of RP. These data support the hypothesis that the death of rods results in decreased oxygen consumption and hyperoxia in the outer retina resulting in gradual cone cell death from oxidative damage. This hypothesis has important therapeutic implications and deserves rapid evaluation.

Topics: Acrolein; Aldehydes; Animals; Animals, Genetically Modified; Biomarkers; Cell Communication; Cell Death; Cell Survival; Disease Models, Animal; DNA Damage; Hyperoxia; Immunohistochemistry; Lipid Peroxidation; Nerve Degeneration; Oxidative Stress; Retinal Cone Photoreceptor Cells; Retinal Rod Photoreceptor Cells; Retinitis Pigmentosa; Sus scrofa

Systemic treatment of mice with the herbicide paraquat causes the selective loss of nigrostriatal dopaminergic neurons, reproducing the primary neurodegenerative feature of Parkinson's disease. To elucidate the role of oxidative damage in paraquat neurotoxicity, the time-course of neurodegeneration was correlated to changes in 4-hydroxy-2-nonenal (4-HNE), a lipid peroxidation marker. When mice were exposed to three weekly injections of paraquat, no nigral dopaminergic cell loss was observed after the first administration, whereas a significant reduction of neurons followed the second exposure. Changes in the number of nigral 4-HNE-positive neurons suggest a relationship between lipid peroxidation and neuronal death, since a dramatic increase in this number coincided with the onset and development of neurodegeneration after the second toxicant injection. Interestingly, the third paraquat administration did not cause any increase in 4-HNE-immunoreactive cells, nor did it produce any additional dopaminergic cell loss. Further evidence of paraquat-induced oxidative injury derives from the observation of nitrotyrosine immunoreactivity in the substantia nigra of paraquat-treated animals and from experiments with ferritin transgenic mice. These mice, which are characterized by a decreased susceptibility to oxidative stress, were completely resistant to the increase in 4-HNE-positive neurons and the cell death caused by paraquat. Thus, paraquat exposure yields a model that emphasizes the susceptibility of dopaminergic neurons to oxidative damage.

Topics: Aldehydes; Analysis of Variance; Animals; Cell Count; Dopamine; Drug Administration Schedule; Ferritins; Herbicides; Humans; Immunohistochemistry; Male; Mice; Mice, Inbred C57BL; Mice, Transgenic; Nerve Degeneration; Oxidative Stress; Paraquat; Promoter Regions, Genetic; Time Factors; Tyrosine; Tyrosine 3-Monooxygenase

The effects of the peripheral benzodiazepine receptor (PBR) ligand, PK11195, were investigated in the rat striatum following the administration of quinolinic acid (QUIN). Intrastriatal QUIN injection caused an increase of PBR expression in the lesioned striatum as demonstrated by immunohistochemical analysis. Double immunofluorescent staining indicated PBR was primarily expressed in ED1-immunoreactive microglia but not in GFAP-immunoreactive astrocytes or NeuN-immunoreactive neurons. PK11195 treatment significantly reduced the level of microglial activation and the expression of pro-inflammatory cytokines and iNOS in QUIN-injected striatum. Oxidative-mediated striatal QUIN damage, characterized by increased expression of markers for lipid peroxidation (4-HNE) and oxidative DNA damage (8-OHdG), was significantly diminished by PK11195 administration. Furthermore, intrastriatal injection of PK11195 with QUIN significantly reduced striatal lesions induced by the excitatory amino acid and diminished QUIN-mediated caspase-3 activation in striatal neurons. These results suggest that inflammatory responses from activated microglia are damaging to striatal neurons and pharmacological targeting of PBR in microglia may be an effective strategy in protecting neurons in neurological disorders such as Huntington's disease.

Topics: 8-Hydroxy-2'-Deoxyguanosine; Aldehydes; Animals; Antineoplastic Agents; Carrier Proteins; Caspases; Corpus Striatum; Cytokines; Deoxyguanosine; Disease Models, Animal; Ectodysplasins; Encephalitis; Gliosis; Huntington Disease; Isoquinolines; Ligands; Male; Membrane Proteins; Microglia; Nerve Degeneration; Neurotoxins; Nitric Oxide Synthase Type II; Oxidative Stress; Quinolinic Acid; Rats; Rats, Sprague-Dawley; Receptors, GABA-A; Tumor Necrosis Factors

Developmental exposure to environmental chemicals may have detrimental effects on embryonic brains that could play a major role in the etio-pathology of fetal and adult neurological diseases. The exact mechanism by which prenatal exposures to environmental agents, such as drinking water disinfectant byproducts (DBP), cause neurological impairment in fetus is not known. Our objective is to examine the impact of prenatal exposure to DBP on fetal brain development. Pregnant CD-1 mice, at the sixth day of gestation (GD-6), received a daily (GD-6-GD-18) oral dose of chloroacetonitrile (CAN, 25 ppm), a member of DBP. To assess fetal brain uptake of CAN, several animals were injected with a tracer dose of 2-[(14)C]-CAN (333 microCi/kg, i.v.), at GD-12 and processed for quantitative in situ micro whole-body autoradiography (QIMWBA) at 1 and 24 h after treatment. The remaining animals continued receiving CAN until GD-18 when fetal brains were processed for biochemical determination of oxidative stress (OS) or prepared for histological examinations. The results indicate a rapid placental transfer and fetal brain uptake of 2-[(14)C]-CAN/metabolites in cortical areas and hippocampus. In treated animals 3-fold decrease in glutathione (GSH), 1.3-fold increase in lipid peroxidation and 1.4-fold increase in DNA oxidation were detected as compared to control. DeOlmos cupric silver staining of fetal brains indicated significant increase in cortical neurodegeneration in treated animals. Immunohistochemical labeling (TUNEL) of apoptotic nuclei in the cortices and choroid plexuses were also increased in treated animals as compared to control. In conclusion, CAN crosses the placental and fetal blood-brain barriers and induces OS that triggered apoptotic neurodegenration in fetal brain. Future studies will examine the molecular mechanisms of these events and its impact on neural development of offspring.

Topics: 8-Hydroxy-2'-Deoxyguanosine; Acetonitriles; Aldehydes; Animals; Apoptosis; Autoradiography; Brain; Brain Chemistry; Deoxyguanosine; Disinfectants; Female; Fetus; Glutathione; Malondialdehyde; Mice; Nerve Degeneration; Neurotoxicity Syndromes; Oxidation-Reduction; Oxidative Stress; Pregnancy; Water Supply

Mutations in parkin are involved in some cases of autosomal recessive juvenile parkinsonism (AR-JP), but it is not known how they result in nigral cell death. We examined the effect of parkin overexpression on the response of cells to various insults. Wild-type and AR-JP-associated mutant parkins (Del3-5, T240R, and Q311X) were overexpressed in NT-2 and SK-N-MC cells. Overexpressed wild-type parkin delayed cell death induced by serum withdrawal, H(2)O(2), 1-methyl-4-phenylpyridinium (MPP(+)), or 4-hydroxy-2-trans-nonenal (HNE) but did not delay cell death caused by the proteasome inhibitor lactacystin. Increases in damage to proteins (protein carbonyls and 3-nitrotyrosine) were attenuated by wild-type parkin after serum withdrawal or exposure to H(2)O(2), MPP(+), or HNE but not after exposure to lactacystin. The mutant parkins (of all types) markedly accelerated cell death in response to all the insults, accompanied by increased levels of 8-hydroxyguanine, protein carbonyls, lipid peroxidation, and 3-nitrotyrosine and decreased levels of GSH. The viability loss induced by all the insults showed apoptotic features. The presence of parkin mutations in substantia nigra in Parkinson's disease may increase neuronal vulnerability to a range of toxic insults.

Topics: 1-Methyl-4-phenylpyridinium; Acetylcysteine; Aldehydes; Apoptosis; Cell Death; Cell Line, Tumor; Drug Resistance; Enzyme Inhibitors; Genetic Predisposition to Disease; Glutamic Acid; Guanine; Humans; Hydrogen Peroxide; Mutation; Nerve Degeneration; Neurons; Neurotoxins; Oxidative Stress; Parkinsonian Disorders; Proteasome Endopeptidase Complex; Proteasome Inhibitors; Substantia Nigra; Tyrosine; Ubiquitin-Protein Ligases

The role of reactive oxygen-induced oxidative damage to lipids (i.e., lipid peroxidation, LP) and proteins has been strongly supported in previous work. Most notably, a number of free radical scavengers and lipid antioxidants have been demonstrated to be neuroprotective in traumatic brain injury (TBI) models. However, the specific sources of reactive oxygen species (ROS), the time course of oxidative damage and its relationship to post-traumatic neurodegeneration in the injured brain have been incompletely defined. The present study was directed at an investigation of the role of the ROS, peroxynitrite (PON), in the acute pathophysiology of TBI and its temporal relationship to neurodegeneration in the context of the mouse model of diffuse head injury model. Male CF-1 mice were subjected to a moderately severe head injury and assessed at 1-, 3-, 6-, 12-, 24-, 48-, 72, 96- and 120-h post-injury for neurodegeneration using quantitative image analysis of silver staining and semi-quantitative analysis of PON-mediated oxidative damage to proteins (3-nitrotyrosine, 3-NT) and lipids (4-hydroxynonenal, 4-HNE). Significant evidence of silver staining was not apparent until 24-h post-injury, with peak staining seen between 72- and 120-h. This time-course of neurodegeneration was preceded by intense immunostaining for 3-NT and 4-HNE, which occurred within the first hour post-injury. The time course and staining pattern for 3-NT and 4-HNE were similar, with the highest staining intensity noted within the first 48-h in areas surrounding trauma-induced contusions. In the case of 3-NT, neuronal perikarya and processes and microvessels displayed staining. The temporal and spatial coincidence of protein nitration and LP damage suggests that PON is involved in both. However, lipid-peroxidative (4-HNE) immunoreactivity was broader and more diffuse than 3-NT, suggesting that other reactive oxygen mechanisms, such as iron-dependent LP, may also contribute to the more widespread 4-HNE immunoreactivity. This indicates that optimal pharmacological inhibition of post-traumatic oxidative damage in TBI may need to combine two functionalities: one to scavenge PON or PON-derived radicals, and the second to inhibit LP caused by multiple ROS species.

Topics: Aldehydes; Animals; Brain; Brain Injuries; Disease Models, Animal; Image Processing, Computer-Assisted; Immunohistochemistry; Lipid Peroxidation; Male; Mice; Nerve Degeneration; Peroxynitrous Acid; Proteins; Time Factors; Tyrosine

We have previously shown that antioxidants such as a-phenyl-tert-butyl nitrone or N-acetylcysteine attenuate cortical neuronal injury in infant rats with bacterial meningitis, suggesting that oxidative alterations play an important role in this disease. However, the precise mechanism(s) by which antioxidants inhibit this injury remain(s) unclear. We therefore studied the extent and location of protein oxidation in the brain using various biochemical and immunochemical methods. In cortical parenchyma, a trend for increased protein carbonyls was not evident until 21 hours after infection and the activity of glutamine synthetase (another index of protein oxidation) remained unchanged. Consistent with these results, there was no evidence for oxidative alterations in the cortex by various immunohistochemical methods even in cortical lesions. In contrast, there was a marked increase in carbonyls, 4-hydroxynonenal protein adducts and manganese superoxide dismutase in the cerebral vasculature. Elevated lipid peroxidation was also observed in cerebrospinal fluid and occasionally in the hippocampus. All of these oxidative alterations were inhibited by treatment of infected animals with N-acetylcysteine or alpha-phenyl-tert-butyl nitrone. Because N-acetylcysteine does not readily cross the blood-brain barrier and has no effect on the loss of endogenous brain antioxidants, its neuroprotective effect is likely based on extraparenchymal action such as inhibition of vascular oxidative alterations.

Topics: Alcohol Oxidoreductases; Aldehydes; Animals; Antioxidants; Cerebral Arteries; Cyclic N-Oxides; Cystine; Encephalitis; Female; Free Radical Scavengers; Glutamate-Ammonia Ligase; Lipid Peroxidation; Meningitis, Bacterial; Nerve Degeneration; Nerve Tissue Proteins; Neuroprotective Agents; Nitrogen Oxides; Oxidative Stress; Rats; Reactive Oxygen Species; Streptococcus pneumoniae; Superoxide Dismutase

Beta-amyloid is one of the most significant features of Alzheimer's disease, and has been considered to play a pivotal role in neurodegeneration through an unknown mechanism. However, it has been noted that beta-amyloid accumulation is associated with markers of oxidative stress including protein oxidation (Smith et al., 1997), lipid peroxidation (Mark et al., 1997; Sayre et al., 1997), advanced glycation end products (Smith et al., 1994), and oxidation of nucleic acids (Nunomura et al., 1999). Furthermore, studies from cultured cells have shown that beta-amyloid leads to an increase in hydrogen peroxide levels (Behl et al., 1994), and the production of reactive oxygen intermediates (Harris et al., 1995). Taken together, this evidence supports the idea that beta-amyloid plays a key role in oxidative stress-evoked neuropathology. In this study, we examined the induction of oxidative stress in response to amyloid load in a mouse model of Alzheimer's disease. The mice carrying mutant amyloid precursor protein and presenilins-1 (Goate et al., 1991; Hardy, 1997), develops beta-amyloid deposits at 10-12 weeks of age and show several features of the human disease (Holcomb et al., 1998; Matsuoka et al., 2001; McGowan et al., 1999; Takeuchi et al., 2000; Wong et al., 1999). Both 3-nitrotyrosine and 4-hydroxy-2-nonenal (protein and lipid oxidative stress markers, respectively) associate strongly with fibrillar beta-amyloid, but not with diffuse (thioflavine S negative) beta-amyloid, and the levels increase in relation to the age-associated increase in fibrillar amyloid load.From these data we suggest that fibrillar beta-amyloid is associated with oxidative damage which may influence disease progression in the Alzheimer's disease brain.

Topics: Aging; Aldehydes; Alzheimer Disease; Amyloid beta-Peptides; Animals; Benzothiazoles; Brain; Disease Models, Animal; Immunohistochemistry; Mice; Mice, Neurologic Mutants; Mice, Transgenic; Nerve Degeneration; Neurofibrillary Tangles; Oxidative Stress; Thiazoles; Tyrosine

The distribution of cytoplasmic phospholipase A2 (cPLA2), 4-hydroxynonenal (HNE), and choline acetyltransferase (ChAT) was studied in the septum and hippocampus of rats at various time intervals after fimbria-fornix (FF) transection. Very little cPLA2 or HNE immunoreactivity was observed in the normal medial or lateral septum, whereas a large increase in immunoreactivity with both antibodies was observed in the lateral septum one week after transection. The increase in cPLA2 or HNE staining in the lateral septum after FF transection was completely blocked by intraperitoneal injections (once daily) of a lipophilic inhibitor of phospholipase A2, quinacrine (5 mg/kg), showing the importance of phospholipase A2 in generation of arachidonic acid, which is a target for lipid peroxidation and formation of 4-hydroxynonenal. Quinacrine prevented not only a rise in HNE immunoreactivity, but also a rise in cPLA2 immunoreactivity, showing that cPLA2 expression itself is depressed by the drug, in addition to its well-known effect on blocking the catalytic action of phospholipase A2. No increase in cPLA2 or HNE immunoreactivity was observed in neurons of the medial septum after fimbria-fornix transection, even though these showed a decrease in ChAT staining after the lesion. This suggests that glutamate released from transected hippocamposeptal afferents or increased activity of the supramammillary area following FF transection may lead to increased cPLA2 and HNE immunreactivity, whereas retrograde degeneration in neurons may not. We conclude that there is free-radical damage, as evidenced by HNE formation in neurons of the lateral septum after fimbria-fornix transection, and that this increase in HNE is dependent on phospholipase A2 activity.

Topics: Acetylcholine; Aldehydes; Animals; Choline O-Acetyltransferase; Cytoplasm; Enzyme Inhibitors; Fornix, Brain; Glutamic Acid; Immunohistochemistry; Lipid Peroxidation; Male; Microscopy, Electron; Nerve Degeneration; Neurons; Phospholipases A; Phospholipases A2; Quinacrine; Rats; Rats, Wistar; Septal Nuclei; Time Factors; Up-Regulation

Oxidative stress and lipid peroxidation may contribute to the pathology of neurodegenerative disorders such as Alzheimer's disease (AD) and cerebral ischemia. 4-Hydroxynonenal (4-HNE) is a toxic by-product of lipid peroxidation, and immunoreactivity to 4-HNE has been used to examine lipid peroxidation in the pathogenesis of AD and ischemia. This study sought to determine 1) if there are cellular alterations in 4-HNE immunoreactivity in the human hippocampus after global ischemia, and 2) whether possession of an apolipoprotein E (APOE) epsilon4 allele influenced the extent of 4-HNE immunoreactivity. 4-HNE immunoreactivity was assessed semi-quantitatively in the temporal lobe of a group of controls (n = 44) and in a group of patients who had an episode of global ischemia as a result of a cardiorespiratory arrest and subsequently died (n = 56, survival ranged from 1hr to 42 days). There was minimal cellular 4-HNE immunoreactivity in the control group. However, compared to controls, 4-HNE immunoreactivity was significantly increased in neurons (p < 0.0002) and glia (p < 0.0001) in the hippocampal formation after global ischemia. Possession of an APOE epsilon4 allele did not influence the extent of neuronal or glial 4-HNE immunostaining in the control or global ischemia group. There was a significant negative correlation between the extent of neuronal 4-HNE immunoreactivity with survival period after global ischemia (r2 = 0.0801; p < 0.036) and a significant positive correlation between the extent of glial 4-HNE immunoreactivity and survival after global ischemia (r2 = 0.2958; p < 0.0001). The data indicate a marked increase in neuronal and glial 4-HNE. This substantiates a role for lipid peroxidation in the pathogenesis of cerebral ischemia. There was no indication that APOE genotype influenced the extent of 4-HNE immunoreactivity.

Topics: Adolescent; Adult; Aged; Aged, 80 and over; Aldehydes; Alleles; Apolipoprotein E4; Apolipoproteins E; Brain Ischemia; Cell Membrane; Female; Genotype; Heart Arrest; Hippocampus; Humans; Immunohistochemistry; Lipid Peroxidation; Male; Middle Aged; Nerve Degeneration; Neuroglia; Neurons; Oxidative Stress; Survival Rate

Peroxidation of membrane lipids occurs in many different neurodegenerative conditions including stroke, and Alzheimer's and Parkinson's diseases. Recent findings suggest that lipid peroxidation can promote neuronal death by a mechanism involving production of the toxic aldehyde 4-hydroxy-2,3-nonenal (HNE), which may act by covalently modifying proteins and impairing their function. The transcription factor NF-kappa B can prevent neuronal death in experimental models of neurodegenerative disorders by inducing the expression of anti-apoptotic proteins including Bcl-2 and manganese superoxide dismutase. We now report that HNE selectively suppresses basal and inducible NF-kappa B DNA binding activity in cultured rat cortical neurons. Immunoprecipitation-immunoblot analyses using antibodies against HNE-conjugated proteins and p50 and p65 NF-kappa B subunits indicate that HNE does not directly modify NF-kappa B proteins. Moreover, HNE did not affect NF-kappa B DNA-binding activity when added directly to cytosolic extracts, suggesting that HNE inhibits an upstream component of the NF-kappa B signaling pathway. Inhibition of the survival-promoting NF-kappa B signaling pathway by HNE may contribute to neuronal death under conditions in which membrane lipid peroxidation occurs.

Topics: Aldehydes; Alzheimer Disease; Animals; Apoptosis; Cell Survival; Cells, Cultured; Cerebral Cortex; Cycloheximide; Cysteine Proteinase Inhibitors; Enzyme Inhibitors; Lipid Peroxidation; Nerve Degeneration; Neurons; NF-kappa B; Okadaic Acid; Protein Synthesis Inhibitors; Rats; Stroke; Transcription Factor AP-1; Vanadates

Several lines of evidence support the role of oxidative stress, including increased lipid peroxidation, in the pathogenesis of Alzheimer's disease (AD). Lipid peroxidation generates various reactive aldehydes, such as 4-hydroxynonenal (HNE), which have been detected immunochemically in AD, particularly in neurofibrillary tangles, one of the major diagnostic lesions in AD brains. A recent study demonstrated that acrolein, the most reactive among the alpha,beta-unsaturated aldehyde products of lipid peroxidation, could be rapidly incorporated into proteins, generating a carbonyl derivative, a marker of oxidative stress to proteins. The current studies used an antibody raised against acrolein-modified keyhole limpet hemocyanin (KLH) to test whether acrolein modification of proteins occurs in AD. Double immunofluorescence revealed strong acrolein-KLH immunoreactivity in more than half of all paired helical filament (PHF)-1-labeled neurofibrillary tangles in AD cases. Acrolein-KLH immunoreactivity was also evident in a few neurons lacking PHF-1-positive neurofibrillary tangles. Light acrolein-KLH immunoreactivity occurred in dystrophic neurites surrounding the amyloid-beta core, which itself lacked acrolein-KLH staining. The pattern of acrolein-KLH immunostaining was similar to that of HNE. Control brains did not contain any acrolein-KLH-immunoreactive structures. The current results suggest that protein-bound acrolein is a powerful marker of oxidative damage to protein and support the hypothesis that lipid peroxidation and oxidative damage to protein may play a crucial role in the formation of neurofibrillary tangles and to neuronal death in AD.

Topics: Acrolein; Adult; Aged; Aldehydes; Alzheimer Disease; Antibody Specificity; Biomarkers; Cysteine Proteinase Inhibitors; Cytoskeleton; Female; Humans; Lipid Peroxidation; Male; Middle Aged; Nerve Degeneration; Neurofibrillary Tangles; Neurons; Oxidative Stress

A destructive cycle of oxidative stress and mitochondrial dysfunction is proposed in neurodegenerative disease. Lipid peroxidation, one outcome of oxidative challenge, can lead to the formation of 4-hydroxy-2(E)-nonenal (HNE), a lipophilic alkenal that forms stable adducts on mitochondrial proteins. In this study, we characterized the effects of HNE on brain mitochondrial respiration. We used whole rat brain mitochondria and concentrations of HNE comparable to those measured in patients with Alzheimer's disease. Our results showed that HNE inhibited respiration at multiple sites. Complex I-linked and complex II-linked state 3 respirations were inhibited by HNE with IC50 values of approximately 200 microM HNE. Respiration was apparently diminished owing to the inhibition of complex III activity. In addition, complex II activity was reduced slightly. The lipophilicity and adduction characteristics of HNE were responsible for the effects of HNE on respiration. The inhibition of respiration was not prevented by N-acetylcysteine or aminoguanidine. Studies using mitochondria isolated from porcine cerebral cortex also demonstrated an inhibition of complex I- and complex II-linked respiration. Thus, in neurodegenerative disease, oxidative stress may impair mitochondrial respiration through the production of HNE.

Topics: Aldehydes; Animals; Cell Respiration; Cysteine Proteinase Inhibitors; Dose-Response Relationship, Drug; Electron Transport Complex II; Electron Transport Complex III; Lipid Peroxidation; Male; Mitochondria; Multienzyme Complexes; NAD(P)H Dehydrogenase (Quinone); Nerve Degeneration; Neurons; Oxidoreductases; Rats; Rats, Sprague-Dawley; Succinate Dehydrogenase; Swine

Astrocytes possess plasma membrane glutamate transporters that rapidly remove glutamate from the extracellular milieu and thereby prevent excitotoxic injury to neurons. Cellular oxidative stress is increased in neural tissues in a variety of acute and chronic neurodegenerative conditions. Recent findings suggest that oxidative stress increases neuronal vulnerability to excitotoxicity and that membrane lipid peroxidation plays a key role in this process. We now report that 4-hydroxynonenal (HNE), an aldehydic product of membrane lipid peroxidation, impairs glutamate transport in cultured cortical astrocytes. Impairment of glutamate transport occurred within 1-3 h of exposure to HNE; FeSO4, an inducer of membrane lipid peroxidation, also impaired glutamate transport. Vitamin E prevented impairment of glutamate transport induced by FeSO4, but not that induced by HNE, consistent with HNE acting as an effector of lipid peroxidation-induced impairment of glutamate transport. Glutathione, which binds and thereby detoxifies HNE, prevented HNE from impairing glutamate transport. Western blot, immunoprecipitation, and immunocytochemical analyses using an antibody against HNE-protein conjugates provided evidence that HNE covalently binds to many different astrocytic proteins including the glutamate transporter GLT-1. Data further suggest that HNE promotes intermolecular cross-linking of GLT-1 monomers to form dimers. HNE also induced mitochondrial dysfunction and accumulation of peroxides in astrocytes. Impairment of glutamate transport and mitochondrial function occurred with sublethal concentrations of HNE, concentrations known to be generated in cells exposed to various oxidative insults. Collectively, our data suggest that HNE may be an important mediator of oxidative stress-induced impairment of astrocytic glutamate transport and may thereby play a role in promoting neuronal excitotoxicity.

Topics: Aldehydes; Animals; Antioxidants; Astrocytes; Blotting, Western; Cells, Cultured; Cerebral Cortex; Cysteine Proteinase Inhibitors; Glutamic Acid; Immunohistochemistry; L-Lactate Dehydrogenase; Lipid Peroxidation; Mitochondria; Nerve Degeneration; Oxidative Stress; Precipitin Tests; Rats; Rats, Sprague-Dawley

Increasing age and inheritance of the epsilon 4 allele of apolipoprotein E (APOE4) are significant risk factors for sporadic and late onset familial Alzheimer disease (AD); however, the mechanisms by which either leads to AD are unknown. Numerous studies have associated advancing age with increased indices of oxidative challenge to brain, and with still further increased oxidative damage to relevant brain regions in AD patients. A major consequence of oxidative damage to brain is lipid peroxidation with production of the neurotoxic metabolite 4-hydroxy-2-nonenal (HNE). HNE reacts with protein to yield several adducts, including a pyrrole adduct that forms irreversibly in biological systems. Previously, we have shown in a small number of AD and control patients that HNE pyrrole adduct antiserum is immunoreactive with neurofibrillary tangles (NFT), and that this reactivity was significantly associated with inheritance of APOE4. Others have confirmed this pattern of immunoreactivity in AD brain but did not observe an association with APOE4. Herein, we have expanded the study group to 19 AD patients homozygous for APOE4 or APOE3, as well as 30 patients with other neurodegenerative diseases, including diffuse Lewy body disease, Pick's disease, progressive supranuclear palsy, Parkinson's disease, and human immunodeficiency virus-1 encephalitis. HNE pyrrole adduct immunoreactivity on NFT in AD patients was strongly associated with APOE4 homozygosity. With the exception of rare immunoreactive Pick bodies in one case of Pick's disease, no other structure was recognized by HNE pyrrole adduct antiserum in this series of patients. We propose that there is a significant difference between the interaction of apoE3 and apoE4 with lipid peroxidation in the brains of AD patients.

Topics: Adult; Aged; Aged, 80 and over; Aldehydes; Alzheimer Disease; Apolipoprotein E3; Apolipoprotein E4; Apolipoproteins E; Brain; DNA Adducts; Female; Genotype; Homozygote; Humans; Male; Middle Aged; Nerve Degeneration; Nervous System Diseases; Pyrroles