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Neurodegeneration in Parkinson's disease (PD) can be recapitulated in animals by administration of α-synuclein preformed fibrils (PFFs) into the brain. However, the mechanism by which these PFFs induce toxicity is unknown. Iron is implicated in PD pathophysiology, so we investigated whether α-synuclein PFFs induce ferroptosis, an iron-dependent cell death pathway. A range of ferroptosis inhibitors were added to a striatal neuron-derived cell line (STHdhQ7/7 cells), a dopaminergic neuron-derived cell line (SN4741 cells), and WT primary cortical neurons, all of which had been intoxicated with α-synuclein PFFs. Viability was not recovered by these inhibitors except for liproxstatin-1, a best-in-class ferroptosis inhibitor, when used at high doses. High-dose liproxstatin-1 visibly enlarged the area of a cell that contained acidic vesicles and elevated the expression of several proteins associated with the autophagy-lysosomal pathway similarly to the known lysosomal inhibitors, chloroquine and bafilomycin A1. Consistent with high-dose liproxstatin-1 protecting via a lysosomal mechanism, we further de-monstrated that loss of viability induced by α-synuclein PFFs was attenuated by chloroquine and bafilomycin A1 as well as the lysosomal cysteine protease inhibitors, leupeptin, E-64D, and Ca-074-Me, but not other autophagy or lysosomal enzyme inhibitors. We confirmed using immunofluorescence microscopy that heparin prevented uptake of α-synuclein PFFs into cells but that chloroquine did not stop α-synuclein uptake into lysosomes despite impairing lysosomal function and inhibiting α-synuclein toxicity. Together, these data suggested that α-synuclein PFFs are toxic in functional lysosomes in vitro. Therapeutic strategies that prevent α-synuclein fibril uptake into lysosomes may be of benefit in PD.

Adrenergic β receptor activation prevents human soluble amyloid β (Aβ)-induced impairment of long-term potentiation (LTP) in slices. On the basis of the evidence that human Aβ1-42-induced impairment of LTP is due to Aβ1-42-mediated Zn2+ toxicity, we postulated that adrenergic β receptor activation reduces Aβ1-42-mediated intracellular Zn2+ toxicity followed by rescuing Aβ1-42 toxicity. To test the effect of adrenergic β receptor activation, LTP was recorded at perforant pathway-dentate granule cell synapses of anesthetized rats 60 min after Aβ1-42 injection into the dentate granule cell layer. Human Aβ1-42-induced impairment of LTP was rescued by co-injection of isoproterenol, an adrenergic β receptor agonist, but not by co-injection of phenylephrine, an adrenergic α1 receptor agonist. Isoproterenol did not reduce Aβ1-42 uptake into dentate granule cells, but reduced increase in intracellular Zn2+ in dentate granule cells induced by Aβ1-42. In contrast, phenylephrine did not reduce both Aβ1-42 uptake and increase in intracellular Zn2+ by Aβ1-42. In the case of human Aβ1-40 and rat Aβ1-42, which do not increase intracellular Zn2+, human Aβ1-40- and rat Aβ1-42-induced impairments of LTP were not rescued by co-injection of isoproterenol. The present study indicates that adrenergic β receptor activation reduces Aβ1-42-mediated increase in intracellular Zn2+ in dentate granule cells, resulting in rescuing Aβ1-42-induced impairment of LTP. It is likely that noradrenergic neuron activation by stimulating the locus coeruleus is effective for rescuing Aβ1-42-induced cognitive decline that is caused by intracellular Zn2+ dysregulation in the hippocampus.

Human amyloid-β1-40 (Aβ1-40) and rat Aβ1-42 have lower affinity for extracellular Zn2+ than human Aβ1-42. Here we report extracellular Zn2+-independent attenuation of dentate gyrus long-term potentiation (LTP) by human Aβ1-40 and rat Aβ1-42. On the basis of the data that dentate gyrus LTP is extracellular Zn2+-dependently attenuated after local injection of human Aβ1-42 (25 pmol, 1 μl) into the dentate gyrus, which increases intracellular Zn2+ in the dentate gyrus, the toxicity of human Aβ1-40 and rat Aβ1-42 was compared in the in vivo system with human Aβ1-42. Dentate gyrus LTP was attenuated after injection of human Aβ1-40 and rat Aβ1-42 (25 pmol, 1 μl) into the dentate gyrus, which did not increase intracellular Zn2+ in the dentate gyrus. The attenuated LTP was not rescued by co-injection of CaEDTA, an extracellular Zn2+ chelator. The present study suggests that human Aβ1-40 and rat Aβ1-42 affect cognitive activity via extracellular Zn2+-independent mechanism at low micromolar concentration.

A number of recent studies have suggested the ubiquitin proteasome system (UPS) in schizophrenia is dysfunctional. The purpose of this study was to investigate UBE2K, a ubiquitin-conjugating (E2) enzyme within the UPS that has been associated with psychosis symptom severity, in the blood and brain of individuals with schizophrenia. Whole blood and erythrocytes from 128 (71 treatment-resistant schizophrenia, 57 healthy controls) individuals as well as frozen dorsolateral prefrontal cortex (DLPFC) and orbitofrontal cortex (OFC) post-mortem samples from 74 (37 schizophrenia, 37 controls) individuals were obtained. UBE2K gene expression was assayed in whole blood and DLPFC samples, whereas protein levels were assayed in erythrocytes and OFC samples. Elevated levels of UBE2K mRNA were observed in whole blood of individuals with schizophrenia (p = 0.03) but not in the DLPFC, while protein levels were raised in erythrocytes and the OFC (p

The accumulation of amyloid-β1–42 (Aβ1–42), a constituively-generated peptide, in the brain is considered an upstream event in pathogenesis of Alzheimer’s disease. Aβ1–42-induced pathophysiology has been extensively studied in experimental mice and rats. However, neurotoxicity of murine Aβ1–42 is much less understood than human Aβ1–42. Here we report difference in ability for extracellular Zn2+ influx into dentate granule cells of rats between human and rat Aβ1–42 and its significance. Human Aβ1–42 rapidly increased intracellular Zn2+, which was determined with intracellular ZnAF-2, in dentate granule cells, 5 min after injection of Aβ1–42 (25 μM, 1 μl) into the dentate gyrus, while rat Aβ1–42 did not increase intracellular Zn2+. In vivo perforant pathway LTP was attenuated under pre-perfusion with 5 nM human Aβ1–42 in artificial cerebrospinal fluid (ACSF) containing 10 nM Zn2+, recapitulating the concentration of extracellular Zn2+, but not with 5 nM rat Aβ1–42 in ACSF containing 10 nM Zn2+. The present study suggests that rat Aβ1–42 has lower affinity for extracellular Zn2+ than human Aβ1–42 and does not capture Zn2+ in the extracellular compartment, resulting in no significant effect on cognitive activity of rat even in the range of very low nanomolar concentrations of endogenous Aβ1–42.

The tripeptide glutathione (GSH) and its oxidized form glutathione disulfide (GSSG) constitute a key redox couple in cells. In particular, they partner protein thiols in reversible thiol-disulfide exchange reactions that act as switches in cell signaling and redox homeostasis. Disruption of these processes may impair cellular redox signal transduction and induce redox misbalances that are linked directly to aging processes and to a range of pathological conditions including cancer, cardiovascular diseases and neurological disorders. Glutaredoxins are a class of GSH-dependent oxidoreductase enzymes that specifically catalyze reversible thiol-disulfide exchange reactions between protein thiols and the abundant thiol pool GSSG/GSH. They protect protein thiols from irreversible oxidation, regulate their activities under a variety of cellular conditions and are key players in cell signaling and redox homeostasis. On the other hand, they may also function as metal-binding proteins with a possible role in the cellular homeostasis and metabolism of essential metals copper and iron. However, the molecular basis and underlying mechanisms of glutaredoxin action remain elusive in many situations. This review focuses specifically on these aspects in the context of recent developments that illuminate some of these uncertainties.

Although the neurogenesis-enhancing effects of exercise have been extensively studied, the molecular mechanisms underlying this response remain unclear. Here, we propose that this is mediated by the exercise-induced systemic release of the antioxidant selenium transport protein, selenoprotein P (SEPP1). Using knockout mouse models, we confirmed that SEPP1 and its receptor low-density lipoprotein receptor-related protein 8 (LRP8) are required for the exercise-induced increase in adult hippocampal neurogenesis. In vivo selenium infusion increased hippocampal neural precursor cell (NPC) proliferation and adult neurogenesis. Mimicking the effect of exercise through dietary selenium supplementation restored neurogenesis and reversed the cognitive decline associated with aging and hippocampal injury, suggesting potential therapeutic relevance. These results provide a molecular mechanism linking exercise-induced changes in the systemic environment to the activation of quiescent hippocampal NPCs and their subsequent recruitment into the neurogenic trajectory.

On the basis of the evidence that the basolateral amygdala (BLA) modulates hippocampal memory processes via synaptic plasticity, here we report that adrenergic β receptor activation in the BLA rescues amyloid β1-42 (Aβ1-42)-induced attenuation of long-term potentiation (LTP) at perforant pathway-dentate granule cell (DGC) synapses. When 500 μM isoproterenol (2 μl), an adrenergic β receptor agonist, was injected into the BLA 20 min before LTP induction, LTP was enhanced. Isoproterenol-mediated enhancement of LTP was blocked by co-injection with 100 μM ZnAF-2DA, an intracellular Zn2+ chelator, suggesting that intracellular Zn2+ is required for the intracellular signaling cascade after adrenergic β receptor activation in the BLA. Aβ1-42-induced attenuation of LTP, which was induced by Aβ1-42 injection into the dentate gyrus 60 min before LTP induction, was rescued by isoproterenol injection into the BLA 20 min before LTP induction, but not by 500 μM phenylephrine (2 μl), an adrenergic α1 receptor agonist, injection into the BLA, which did not enhance LTP unlike the case of isoproterenol injection. Interestingly, Aβ1-42-induced attenuation of LTP was also rescued by 100 μM isoproterenol injection into the BLA 20 min before LTP induction, which did not enhance LTP. The present study demonstrates that adrenergic β receptor activation in the BLA, which is linked with intracellular Zn2+ signaling, rescues Aβ1-42-induced attenuation of dentate gyrus LTP. It is likely that adrenergic β receptor activation in the BLA is a strategy for rescuing Aβ1-42-induced cognitive decline that is associated with hippocampal synaptic plasticity.

Introduction While metals have been implicated in the pathophysiology of Parkinson's disease (PD), the clinical evidence is scarce. Further, the contribution of metals for the risk or clinical presentation of PD remains to be explored. Methods To investigate the associations between the level of metals in blood serum and PD risk or clinical presentation, including sex-related differences, we studied 325 PD patients and age- and sex-matched 304 controls. We collected clinical data of the PD patients, including age at onset, PD duration, levodopa-equivalent dose (LED), Hoehn and Yahr stage (H-Y stage), presence of motor fluctuation, levodopa-induced dyskinesia (LID), freezing of gait, hallucination, and Mini-Mental State Examination (MMSE) score. Iron, copper, and zinc levels in serum were assayed by inductively coupled plasma mass spectrometry. Statistical analyses were performed to determine the sex-related differences in metal levels. Results Among the three metal elements tested, serum copper levels showed significant correlations with PD risk or clinical presentation. Higher copper levels were associated with a decreased PD risk. Higher copper or lower iron levels were associated with the risk of LID in women. Serum copper levels were negatively correlated with MMSE scores in PD patients. Conclusions This clinical study suggests significant associations between serum metal levels and PD risk or essential clinical features, demonstrating the possible roles of metals in PD pathogenesis or symptom development.

Cellular senescence is characterised by the irreversible arrest of proliferation, a pro-inflammatory secretory phenotype and evasion of programmed cell death mechanisms. We report that senescence alters cellular iron acquisition and storage and also impedes iron-mediated cell death pathways. Senescent cells, regardless of stimuli (irradiation, replicative or oncogenic), accumulate vast amounts of intracellular iron (up to 30-fold) with concomitant changes in the levels of iron homeostasis proteins. For instance, ferritin (iron storage) levels provided a robust biomarker of cellular senescence, for associated iron accumulation and for resistance to iron-induced toxicity. Cellular senescence preceded iron accumulation and was not perturbed by sustained iron chelation (deferiprone). Iron accumulation in senescent cells was driven by impaired ferritinophagy, a lysosomal process that promotes ferritin degradation and ferroptosis. Lysosomal dysfunction in senescent cells was confirmed through several markers, including the build-up of microtubule-associated protein light chain 3 (LC3-II) in autophagosomes. Impaired ferritin degradation explains the iron accumulation phenotype of senescent cells, whereby iron is effectively trapped in ferritin creating a perceived cellular deficiency. Accordingly, senescent cells were highly resistant to ferroptosis. Promoting ferritin degradation by using the autophagy activator rapamycin averted the iron accumulation phenotype of senescent cells, preventing the increase of TfR1, ferritin and intracellular iron, but failed to re-sensitize these cells to ferroptosis. Finally, the enrichment of senescent cells in mouse ageing hepatic tissue was found to accompany iron accumulation, an elevation in ferritin and mirrored our observations using cultured senescent cells., Graphical abstract fx1, Highlights • Altered iron homeostasis in senescent cells is driven by impaired ferritinophagy. • Impaired ferritinophagy causes functional cellular iron deficiency. • senescent cells are resistant to iron mediated cell death including ferroptosis.

Introduction In cognitively normal (CN) older adults, high levels of Aβ-amyloid are associated with significant decline in cognition, especially episodic memory. Several genes have previously been associated with cognition, including APOE, KIBRA, KLOTHO, BDNF, COMT, SPON1 and CSMD1. While some of this variation has been attributed to some of these genes individually, the combined effects of these genes on rates of cognitive decline, particularly in preclinical Alzheimer's Disease remain largely unknown. Methods To elucidate if risk alleles within these genes can be suitably combined to predict cognitive decline 127 CN older adults with elevated PET-ascertained Aβ-amyloid were included in a decision tree analysis to define a "Cognitive Gene Risk Profile" for decline in a verbal episodic memory composite. Results The episodic memory-derived Cognitive Gene Risk Profile defined four groups: APOE e4+ Risk, e4+ Resilient, e4− Risk, e4− Resilient, with the e4+ Risk group declining significantly faster than all other groups (e4+ Resilient, p = 0.0008; e4− Risk, p = 0.025; e4− Resilient, p = 0.0006). The e4+ Risk group also declined significantly faster than all other groups on Global, Clinical Progression and Pre-Alzheimer's cognitive composites. Discussion The defined Cognitive Gene Risk Profile has potential utility in participant selection/stratification for preclinical AD trials that incorporate Aβ-amyloid and where decline in cognition is essential to determine therapeutic effectiveness.

Background Copper and lipid metabolism are intimately linked, sharing a complex, inverse relationship in the periphery (outside of the central nervous system), which remains to be fully elucidated. Scope Copper and lipids have independently been implicated in the pathogenesis of diseases involving dyslipidaemia, including obesity, cardiovascular disease and non-alcoholic fatty liver disease and also in Wilson disease, an inherited disorder of copper overload. Here we review the relationship between copper and lipid regulatory pathways, which are potential druggable targets for therapeutic intervention. Major conclusions While the inverse relationship between copper and lipids is apparent, tissue-specific roles for the copper regulatory protein, ATP7B provide further insight into the association between copper and lipid metabolism. General significance Understanding the relationship between copper and lipid metabolism is important for identifying druggable targets for diseases with disrupted copper and/or lipid metabolism; and may reveal similar connections within the brain and in neurological diseases with impaired copper and lipid transport.

The publisher regrets the following errors in the above mentioned article: In the original manuscript there were the following errors to figure call outs: • On the 9th line of main text on the left-hand side column on page 5, the call out of Figure 2 should instead be for Figure 3.• On the 17th line of main text on the right-hand side column on page 5, the call out of Figure 4 should instead be for Figure 5.• On the 12th line of main text on the left-hand side column on page 6, the call out of Figure 5 should instead be for Figure 4.In the original manuscript, a correction factor was not applied in calculating the raw values (μg/mL) of several of the proteins presented. The raw values of the following proteins were therefore erroneously presented in Table 2 and Supplementary Figure 2 to be 20-fold higher than their actual concentration: α1-antitrypsin, α1-antichymotrypsin, ceruloplasmin, complement C3, α-fibrinogen, β-fibrinogen, γ-fibrinogen, haptoglobin and hemopexin. Importantly, as this was a multiplication error, and also that the statistical modelling was performed using z-scores and not raw scores, the statistical parameters (β, S.E., P) are identical with the updated protein values, and the interpretation of our findings is unchanged. The updated Supplementary Figure 2 and Table 2 are presented below. The publisher would like to apologise for any inconvenience caused. [Figure presented] Supplementary Figure 2. Levels of APR proteins in CSF according to clinical category. *P < 0.05; **P < 0.01; ***P < 0.001 compared to CN Aβ42/t-tau negative. As panels B–K were exploratory analysis, these were not corrected for multiple testing. Table 2. CSF acute phase protein levels in diagnostic categories. Statistics derived from separate multiple regressions for each acute phase protein, which was adjusted for age, sex, APOE e4 and diagnosis. Values are μg/mL, except for ferritin which is ng/mL and the composite, which is a z-score. Significance is comparison to CN negative group. CN: Cognitively Normal; SCD: Subjective Cognitive Decline; MCI: Mild Cognitive Impairment; AD: Alzheimer's Disease. Bold indicates P < 0.05. The composite was the primary analysis, and the analysis of individual APR proteins was exploratory, and therefore correction for multiple comparisons was not performed. [Table]

Acid fibroblast growth factor (aFGF) has shown neuroprotection in Alzheimer’s disease (AD) models in previous studies, yet its mechanism is still uncertain. Here we report that the efficacy of Tat-haFGF14–154 is markedly increased when loaded cationic liposomes for intranasal delivery are intranasally administered to APP/PS1 mice. Our results demonstrated that liposomal Tat-haFGF14–154 treatment significantly ameliorated behavioral deficits, relieved brain Aβ burden, and increased the expression and activity of disintegrin and metalloproteinase domain-containing protein 10 (ADAM10) in the brain. Tat-haFGF14–154 antagonized Aβ1–42-induced cell death and structural damage in rat primary neurons in an ADAM10-dependent manner, which, in turn, was promoted by the activation of XBP1 splicing and modulated by the PI3K-CREB pathway. Both knockdown of ADAM10 and inhibition of PI3K (LY294002) negated Tat-haFGF14–154 rescue. Thus, Tat-haFGF14–154 activates the IRE1α/XBP1 pathway of the unfolded protein response (UPR) against the endoplasmic reticulum (ER) stress induced by Aβ, and, subsequently, the nuclear translocation of spliced XBP1 (XBP1s) promotes transcription of ADAM10. These results highlight the important role of ADAM10 and its activation through the PI3K-CREB-IRE1α/XBP1 pathway as a key factor in the mechanism of neuroprotection for Tat-haFGF14–154.

Treatments for Alzheimer's disease (AD) directed against the prominent amyloid plaque neuropathology are yet to be proved effective despite many phase 3 clinical trials. There are several other neurochemical abnormalities that occur in the AD brain that warrant renewed emphasis as potential therapeutic targets for this disease. Among those are the elementomic signatures of iron, copper, zinc, and selenium. Here, we review these essential elements of AD for their broad potential to contribute to Alzheimer's pathophysiology, and we also highlight more recent attempts to translate these findings into therapeutics. A reinspection of large bodies of discovery in the AD field, such as this, may inspire new thinking about pathogenesis and therapeutic targets.

Iron deposition in the brain is a feature of normal aging, though in several neurodegenerative disorders, including Alzheimer's disease, the rate of iron accumulation is more advanced than in age-matched controls. Using laser ablation-inductively coupled plasma-mass spectrometry imaging we present here a pilot study that quantitatively assessed the iron content of white and gray matter in paraffin-embedded sections from the frontal cortex of Alzheimer's and control subjects. Using the phosphorus image as a confirmed proxy for the white/gray matter boundary, we found that increased intrusion of iron into gray matter occurs in the Alzheimer's brain compared to controls, which may be indicative of either a loss of iron homeostasis in this vulnerable brain region, or provide evidence of increased inflammatory processes as a response to chronic neurodegeneration. We also observed a trend of increasing iron within the white matter of the frontal cortex, potentially indicative of disrupted iron metabolism preceding loss of myelin integrity. Considering the known potential toxicity of excessive iron in the brain, our results provide supporting evidence for the continuous development of novel magnetic resonance imaging approaches for assessing white and gray matter iron accumulation in Alzheimer's disease.

Pyroglutamate-modified amyloid-β (pE-Aβ) is a highly neurotoxic amyloid-β (Aβ) isoform and is enriched in the brains of individuals with Alzheimer disease compared with healthy aged controls. Pyroglutamate formation increases the rate of Aβ oligomerization and alters the interactions of Aβ with Cu(2+) and lipids; however, a link between these properties and the toxicity of pE-Aβ peptides has not been established. We report here that Aβ3pE-42 has an enhanced capacity to cause lipid peroxidation in primary cortical mouse neurons compared with the full-length isoform (Aβ(1-42)). In contrast, Aβ(1-42) caused a significant elevation in cytosolic reactive oxygen species, whereas Aβ3pE-42 did not. We also report that Aβ3pE-42 preferentially associates with neuronal membranes and triggers Ca(2+) influx that can be partially blocked by the N-methyl-d-aspartate receptor antagonist MK-801. Aβ3pE-42 further caused a loss of plasma membrane integrity and remained bound to neurons at significantly higher levels than Aβ(1-42) over extended incubations. Pyroglutamate formation was additionally found to increase the relative efficiency of Aβ-dityrosine oligomer formation mediated by copper-redox cycling.

In this issue of Cell Chemical Biology, Telling et al. (2017) apply advanced X-ray microscopy techniques to reveal magnetite iron species in plaques from a mouse model of Alzheimer's disease. The characterization of abnormal iron chemistry in the disease model highlights the potential for iron to combine with the β-amyloid peptide and accelerate the disease process.

Schizophrenia is a chronic and often debilitating disorder in which stage of illness appears to influence course, outcome, prognosis and treatment response. Current evidence suggests roles for oxidative, neuroinflammatory, neurotrophic, apoptotic, mitochondrial and glutamatergic systems in the disorder; all targets of N-acetyl cysteine (NAC). A double blind, placebo controlled trial suggested NAC to be beneficial to those diagnosed with schizophrenia. The current manuscript aims to investigate duration of the illness as a key factor that may be modulating the response to NAC in the participants who took part in the study. A sample of 121 participants were randomised in a double fashion to 24 weeks (placebo=62; NAC=59). Clinical and functional variables were collected over the treatment period. Duration of the illness at baseline was grouped into10 years, 10-20 years and20 years. Mixed Model Repeated Measures Analysis was used to explore the effect of illness duration on response to treatment with NAC. A significant interaction between duration of the illness and response to treatment with NAC was consistently found for positive symptoms and functional variables, but not for negative or general symptoms or for side effect related outcomes. The pattern of changes suggests that this mediator effect of duration of illness in response to treatment is more evident in those participants with 20 years or more of illness duration. Our results suggest a potential advantage of adjunctive NAC over placebo on functioning and positive symptoms reduction in those patients with chronic schizophrenia. This has potential for suggesting stage specific treatments.

Risk of developing Alzheimer's disease is increased by older age, genetic factors, and several medical risk factors. Studies have also suggested that dietary and lifestyle factors may influence risk, raising the possibility that preventive strategies may be effective. This body of research is incomplete. However, because the most scientifically supported lifestyle factors for Alzheimer's disease are known factors for cardiovascular diseases and diabetes, it is reasonable to provide preliminary guidance to help individuals who wish to reduce their risk. At the International Conference on Nutrition and the Brain, Washington, DC, July 19–20, 2013, speakers were asked to comment on possible guidelines for Alzheimer's disease prevention, with an aim of developing a set of practical, albeit preliminary, steps to be recommended to members of the public. From this discussion, 7 guidelines emerged related to healthful diet and exercise habits.

Background Evidence from genome-wide association, microarray, and protein studies have indicated dysregulation of genes and proteins within the Ubiquitin Proteasome Pathway (UPP) in the blood and brain of individuals with schizophrenia. However, it is not clear which components of the UPP, if any, are dysregulated in both blood and brain. Methods We obtained frozen postmortem Orbitofrontal Cortex (OFC) tissue from 76 (38 schizophrenia, 38 control) individuals and erythrocytes from 181 participants, comprising 30 individuals with recent onset schizophrenia (mean illness duration=1 year), 63 individuals with schizophrenia treated with clozapine and considered ‘treatment-resistant’ (mean illness duration=17 years), and 88 control participants. Free ubiquitin and ubiquitinated protein levels as well as endogenous ubiquitination and proteasome activity were quantified in erythrocytes and postmortem OFC blind to diagnosis. Results Individuals with schizophrenia had higher levels of ubiquitinated proteins compared to those with recent onset schizophrenia (p Discussion Our results suggest that protein homeostasis may be abnormal in both the blood and brain of those with schizophrenia, particularly in the later stages or specific sub-groups of the illness. Follow-up studies to determine the mechanism by which this abnormality in protein homeostasis arises and whether its presence in blood has prognostic utility are warranted.

Brain-derived neurotrophic factor (BDNF) Val66Met polymorphism has previously been implicated in Alzheimer's disease (AD)-related cognitive impairment. We aimed to determine the relationship between BDNF Val66Met and beta-amyloid (Aβ) on cognitive decline, hippocampal atrophy, and Aβ accumulation over 36 months in 165 healthy adults enrolled in the Australian Imaging, Biomarkers and Lifestyle study. In healthy adults with high Aβ, Met carriers showed significant and moderate-to-large declines in episodic memory, executive function, and language, and greater hippocampal atrophy over 36 months, compared with Val/Val homozygotes. BDNF Val66Met was not found to be related to rates of change in cognition or hippocampal volume in healthy adults with low Aβ. BDNF Val66Met did not relate to the amount of Aβ or to the rate of Aβ accumulation in either group. High Aβ levels coupled with Met carriage may be useful prognostic markers of accelerated cognitive decline and hippocampal degeneration in individuals in the preclinical stage of AD.

Alzheimer's disease is the leading cause of dementia in the elderly and is defined by two pathological hallmarks; the accumulation of aggregated amyloid beta and excessively phosphorylated Tau proteins. The etiology of Alzheimer's disease progression is still debated, however, increased oxidative stress is an early and sustained event that underlies much of the neurotoxicity and consequent neuronal loss. Amyloid beta is a metal binding protein and copper, zinc and iron promote amyloid beta oligomer formation. Additionally, copper and iron are redox active and can generate reactive oxygen species via Fenton (and Fenton-like chemistry) and the Haber-Weiss reaction. Copper, zinc and iron are naturally abundant in the brain but Alzheimer's disease brain contains elevated concentrations of these metals in areas of amyloid plaque pathology. Amyloid beta can become pro-oxidant and when complexed to copper or iron it can generate hydrogen peroxide. Accumulating evidence suggests that copper, zinc, and iron homeostasis may become perturbed in Alzheimer's disease and could underlie an increased oxidative stress burden. In this review we discuss oxidative/nitrosative stress in Alzheimer's disease with a focus on the role that metals play in this process. Recent studies have started to elucidate molecular links with oxidative/nitrosative stress and Alzheimer's disease. Finally, we discuss metal binding compounds that are designed to cross the blood brain barrier and restore metal homeostasis as potential Alzheimer's disease therapeutics.

Rapid phagocytosis of non-opsonized particles including apoptotic cells is an important process that involves direct recognition of the target by multiple scavenger receptors including P2X7 on the phagocyte surface. Using a real-time phagocytosis assay, we studied the effect of serum proteins on this phagocytic process. Inclusion of 1-5% serum completely abolished phagocytosis of non-opsonized YG beads by human monocytes. Inhibition was reversed by pretreatment of serum with 1-10 mM tetraethylenepentamine, a copper/zinc chelator. Inhibitory proteins from the serum were determined as negatively charged glycoproteins (pI < 6) with molecular masses between 100 and 300 kDa. A glycoprotein-rich inhibitory fraction of serum not only abolished YG bead uptake but also inhibited phagocytosis of apoptotic lymphocytes or neuronal cells by human monocyte-derived macrophages. Three copper- and/or zinc-containing serum glycoproteins, ceruloplasmin, serum amyloid P-component, and amyloid precursor protein, were identified, and the purified proteins were shown to inhibit the phagocytosis of beads by monocytes as well as phagocytosis of apoptotic neuronal cells by macrophages. Human adult cerebrospinal fluid, which contains very little glycoprotein, had no inhibitory effect on phagocytosis of either beads or apoptotic cells. These data suggest for the first time that metal-interacting glycoproteins present within serum are able to inhibit the scavenger activity of mononuclear phagocytes toward insoluble debris and apoptotic cells.

Objectives Bipolar disorder (BD) is intricately associated with chronic clinical conditions. Medical comorbidity is not only more prevalent in mood disorders, but is associated with increased costs, cognitive impairment and, ultimately, premature mortality. Oxidative stress and inflammation may mediate part of this association. To further investigate the association between medical comorbidity status and clinical improvement with adjuvant N acetyl cysteine (NAC) in the context of a placebo-controlled trial. Methods Placebo-controlled randomized clinical trial assessing the effect of NAC over 24 weeks. Symptomatic and functional outcomes were collected over the study period. Medical comorbidities were self-reported, and we took special interest in cardiovascular and endocrine conditions. We evaluated change from baseline to endpoint and the interaction between change and reported medical comorbidities. Results Fifty-one percent of patients reported have a cardiovascular or endocrine comorbidity. Although not found for depressive symptoms or quality of life, a significant interaction between medical comorbidity and change scores was consistently found for all functional outcomes. This indicated an advantage of NAC over placebo in those with a clinical comorbidity. Conclusion Systemic illness moderated only the effect of NAC on functioning, not on depression. Demonstrating an improvement in functional outcomes with an agent that modulates redox and inflammatory pathways, this study lends empirical support to the idea that medical and psychiatric comorbidity are additive in contributing to allostatic states. One intriguing possibility is that comorbid clinical illness could be a marker for more severe oxidative stress states – and thus guide antioxidant use – in BD.

Background Evidence is accumulating to support the presence of redox dysregulation in a number of psychiatric disorders, including bipolar disorder. This dysregulation may be amenable to therapeutic intervention. Glutathione is the predominant non-enzymatic intracellular free radical scavenger in the brain, and the most generic of all endogenous antioxidants in terms of action. N-acetylcysteine (NAC) is a glutathione precursor that effectively replenishes brain glutathione. Given the failure of almost all modern trials of antidepressants in bipolar disorder to demonstrate efficacy, and the limited efficacy of mood stabilisers in the depressive phase of the disorder, this is a major unmet need. Method This study reports data on the treatment of 149 individuals with moderate depression during the 2 month open label phase of a randomised placebo controlled clinical trial of the efficacy of 1 g BID of NAC that examined the use of NAC as a maintenance treatment for bipolar disorder. Results In this trial, the estimated mean baseline Bipolar Depression Rating Scale (BDRS) score was 19.7 (SE = 0.8), and the mean BDRS score at the end of the 8 week open label treatment phase was 11.1 (SE = 0.8). This reduction was statistically significant (p

Huntington disease (HD) is a progressive neurodegenerative disorder caused by expression of polyglutamine-expanded mutant huntingtin protein (mhtt). Most evidence indicates that soluble mhtt species, rather than insoluble aggregates, are the important mediators of HD pathogenesis. However, the differential roles of soluble monomeric and oligomeric mhtt species in HD and the mechanisms of oligomer formation are not yet understood. We have shown previously that copper interacts with and oxidizes the polyglutamine-containing N171 fragment of huntingtin. In this study we report that oxidation-dependent oligomers of huntingtin form spontaneously in cell and mouse HD models. Levels of these species are modulated by copper, hydrogen peroxide, and glutathione. Mutagenesis of all cysteine residues within N171 blocks the formation of these oligomers. In cells, levels of oligomerization-blocked mutant N171 were decreased compared with native N171. We further show that a subset of the oligomerization-blocked form of glutamine-expanded N171 huntingtin is rapidly depleted from the soluble pool compared with “native ” mutant N171. Taken together, our data indicate that huntingtin is subject to specific oxidations that are involved in the formation of stable oligomers and that also delay removal from the soluble pool. These findings show that inhibiting formation of oxidation-dependent huntingtin oligomers, or promoting their dissolution, may have protective effects in HD by decreasing the burden of soluble mutant huntingtin.

Oxidative stress has been implicated in several psychiatric illnesses, including schizophrenia. Glutathione is the brain's primary antioxidant and decreased levels of brain glutathione are reported in schizophrenia. Prepulse inhibition (PPI) is a measure of sensory gating, and PPI is reduced in schizophrenia. This study aimed to investigate the effects of brain glutathione depletion on PPI regulation. Rats and mice were treated with the glutathione-depleting agent, 2-cyclohexene-1-one (CHX), and tested for baseline PPI and its disruption by treatment with amphetamine and MK-801. Treatment with CHX caused significant depletion of GSH in frontal cortex and striatum of rats and mice. Baseline PPI and startle were not altered. However, the disruption of PPI after treatment with amphetamine was absent in CHX-treated rats. In contrast, the effect of MK-801 was not altered by CHX-treatment, nor was there any effect of CHX treatment in mice. These data show an interaction of glutathione depletion with the effects of amphetamine treatment on PPI in rats. This effect could reflect loss of plasticity in PPI regulation caused by the additive effects of CHX-induced glutathione depletion and additional oxidative stress caused by amphetamine-induced dopamine release. The significance of these results for schizophrenia is discussed.

Alzheimer's disease (AD) is an incurable dementia, with major risk factors being age and the APOE-e4 allele. AD has a hallmark neuropathology of neuronal death, lipid peroxidation damage, extracellular Ae amyloid and intracellular tau deposition. There is also marked dysregulation of metal homeostasis, with iron elevation reported in cortex (AD) in tandem with the proteinopathies. The major proteins implicated in AD have been found to function in brain iron regulatory system that fails in aging. The amyloid protein precursor, like ceruloplasmin, facilitates the export of iron from cells by stabilizing cell surface ferroportin. Tau impacts on iron export by trafficking APP to the cell surface. CSF ferritin levels predict cognitive decline and conversion of MCI to AD and are associated with Apolipoprotein E levels. In vivo measurement of brain iron by QSM strongly adds to the prediction of cognitive decline in tandem with amyloid PET scans. These evidences, as well as a host of specific post-mortem changes, converge on ferroptosis as the pathogenic mechanism of AD. Anti-ferroptosis molecules have been effective in animal models of neurodegenerative disease, and the anti-ferroptotic chelator deferiprone is currently being tested in a phase 2 randomized controlled trial for AD.

Redox-active copper is implicated in the pathogenesis of Alzheimer disease (AD), β-amyloid peptide (Aβ) aggregation, and amyloid formation. Aβ·copper complexes have been identified in AD and catalytically oxidize cholesterol and lipid to generate H2O2 and lipid peroxides. The site and mechanism of this abnormality is not known. Growing evidence suggests that amyloidogenic processing of the β-amyloid precursor protein (APP) occurs in lipid rafts, membrane microdomains enriched in cholesterol. β- and γ-secretases, and Aβ have been identified in lipid rafts in cultured cells, human and rodent brains, but the role of copper in lipid raft amyloidogenic processing is presently unknown. In this study, we found that copper modulates flotillin-2 association with cholesterol-rich lipid raft domains, and consequently Aβ synthesis is attenuated via copper-mediated inhibition of APP endocytosis. We also found that total cellular copper is associated inversely with lipid raft copper levels, so that under intracellular copper deficiency conditions, Aβ·copper complexes are more likely to form. This explains the paradoxical hypermetallation of Aβ with copper under tissue copper deficiency conditions in AD.

Oxidative stress and reduced brain glutathione (GSH) levels have been reported in psychiatric illnesses including schizophrenia and bipolar disorder. However the role of GSH in cognitive impairment in the illness remains unclear. Treatment of Sprague-Dawley rats and C57Bl/6 mice with 2-cyclohexene-1-one (CHX) dose-dependently reduced striatal and frontal cortical GSH levels similar to those in schizophrenia. In both species, GSH depletion resulted in disruption of short-term spatial recognition memory in a Y-maze test. In conclusion, GSH depletion induces cognitive impairment, which may be relevant to the role of GSH in psychiatric illnesses.

Background Brain glutathione levels are decreased in schizophrenia, a disorder that often is chronic and refractory to treatment. N-acetyl cysteine (NAC) increases brain glutathione in rodents. This study was conducted to evaluate the safety and effectiveness of oral NAC (1 g orally twice daily [b.i.d.]) as an add-on to maintenance medication for the treatment of chronic schizophrenia over a 24-week period. Methods A randomized, multicenter, double-blind, placebo-controlled study. The primary readout was change from baseline on the Positive and Negative Symptoms Scale (PANSS) and its components. Secondary readouts included the Clinical Global Impression (CGI) Severity and Improvement scales, as well as general functioning and extrapyramidal rating scales. Changes following a 4-week treatment discontinuation were evaluated. One hundred forty people with chronic schizophrenia on maintenance antipsychotic medication were randomized; 84 completed treatment. Results Intent-to-treat analysis revealed that subjects treated with NAC improved more than placebo-treated subjects over the study period in PANSS total [−5.97 (−10.44, −1.51), p = .009], PANSS negative [mean difference −1.83 (95% confidence interval: −3.33, −.32), p = .018], and PANSS general [−2.79 (−5.38, −.20), p = .035], CGI-Severity (CGI-S) [−.26 (−.44, −.08), p = .004], and CGI-Improvement (CGI-I) [−.22 (−.41, −.03), p = .025] scores. No significant change on the PANSS positive subscale was seen. N-acetyl cysteine treatment also was associated with an improvement in akathisia ( p = .022). Effect sizes at end point were consistent with moderate benefits. Conclusions These data suggest that adjunctive NAC has potential as a safe and moderately effective augmentation strategy for chronic schizophrenia.

There is accumulating evidence for oxidative stress mechanisms as common pathophysiological pathways in diverse psychiatric disorders, which offers novel treatment targets in oxidation biology systems. Of these the glutathione system has the most favourable theoretical foundation, given its dominance as the most generic of cellular antioxidants. Clinically, this hypothesis has been supported by several recently published studies that have reported on the efficacy of N-acetylcysteine, a glutathione precursor, in the treatment of various psychiatric disorders. This article outlines the multidimensional evidence that currently exists for oxidative stress mechanisms in psychiatric disorders and specifically discusses glutathione as a promising novel therapeutic target.

There has been steadily growing interest in the participation of metal ions (especially, zinc, copper, and iron) in neurobiological processes, such as the regulation of synaptic transmission. Recent descriptions of the release of zinc and copper in the cortical glutamatergic synapse, and influencing the response of the NMDA receptor underscore the relevance of understanding the inorganic milieu of the synapse to neuroscience. Additionally, major neurodegenerative disorders, including Alzheimer's disease and Parkinson's disease, are characterized by elevated tissue iron, and miscompartmentalization of copper and zinc (e.g. accumulation in amyloid). Increasingly sophisticated medicinal chemistry approaches, which correct these metal abnormalities without causing systemic disturbance of these essential minerals, are being tested. These small molecules show promise of being disease-modifying.

Development of a comprehensive therapeutic treatment for the neurodegenerative Alzheimer's disease (AD) is limited by our understanding of the underlying biochemical mechanisms that drive neuronal failure. Numerous dysfunctional mechanisms have been described in AD, ranging from protein aggregation and oxidative stress to biometal dyshomeostasis and mitochondrial failure. In this review we discuss the critical role of amyloid-beta (A beta) in some of these potential mechanisms of neurodegeneration. The 39-43 amino acid A beta peptide has attracted intense research focus since it was identified as a major constituent of the amyloid deposits that characterise the AD brain, and it is now widely recognised as central to the development of AD. Familial forms of AD involve mutations that lead directly to altered A beta production from the amyloid-beta A4 precursor protein, and the degree of AD severity correlates with specific pools of A beta within the brain. A beta contributes directly to oxidative stress, mitochondrial dysfunction, impaired synaptic transmission, the disruption of membrane integrity, and impaired axonal transport. Further study of the mechanisms of A beta mediated neurodegeneration will considerably improve our understanding of AD, and may provide fundamental insights needed for the development of more effective therapeutic strategies.

Biometals play an important role in Alzheimer disease, and recent reports have described the development of potential therapeutic agents based on modulation of metal bioavailability. The metal ligand clioquinol (CQ) has shown promising results in animal models and small phase clinical trials; however, the actual mode of action in vivo has not been determined. We now report a novel effect of CQ on amyloid beta-peptide (Abeta) metabolism in cell culture. Treatment of Chinese hamster ovary cells overexpressing amyloid precursor protein with CQ and Cu(2+) or Zn(2+) resulted in an approximately 85-90% reduction of secreted Abeta-(1-40) and Abeta-(1-42) compared with untreated controls. Analogous effects were seen in amyloid precursor protein-overexpressing neuroblastoma cells. The secreted Abeta was rapidly degraded through up-regulation of matrix metalloprotease (MMP)-2 and MMP-3 after addition of CQ and Cu(2+). MMP activity was increased through activation of phosphoinositol 3-kinase and JNK. CQ and Cu(2+) also promoted phosphorylation of glycogen synthase kinase-3, and this potentiated activation of JNK and loss of Abeta-(1-40). Our findings identify an alternative mechanism of action for CQ in the reduction of Abeta deposition in the brains of CQ-treated animals and potentially in Alzheimer disease patients.

Hypoxia-inducible factor (HIF) prolyl 4-hydroxylases are a family of iron- and 2-oxoglutarate-dependent dioxygenases that negatively regulate the stability of several proteins that have established roles in adaptation to hypoxic or oxidative stress. These proteins include the transcriptional activators HIF-1α and HIF-2α. The ability of the inhibitors of HIF prolyl 4-hydroxylases to stabilize proteins involved in adaptation in neurons and to prevent neuronal injury remains unclear. We reported that structurally diverse low molecular weight or peptide inhibitors of the HIF prolyl 4-hydroxylases stabilize HIF-1α and up-regulate HIF-dependent target genes (e.g. enolase, p21waf1/cip1, vascular endothelial growth factor, or erythropoietin) in embryonic cortical neurons in vitro or in adult rat brains in vivo. We also showed that structurally diverse HIF prolyl 4-hydroxylase inhibitors prevent oxidative death in vitro and ischemic injury in vivo. Taken together these findings identified low molecular weight and peptide HIF prolyl 4-hydroxylase inhibitors as novel neurological therapeutics for stroke as well as other diseases associated with oxidative stress.

Alzheimer disease is characterized by cerebral Abeta deposition, which we have recently discovered occurs also in the lens as cataracts in Alzheimer disease patients. Here we report the presence of significantly increased cataracts in the lenses of an Abeta-transgenic mouse model for Alzheimer disease and their amelioration upon treatment with EUK-189, a synthetic SOD/catalase mimetic. These data support an oxidative etiology for AD-associated lens cataracts and their potential to be treated preventatively with antioxidants.

The amyloid beta peptide (Abeta) is toxic to neuronal cells, and it is probable that this toxicity is responsible for the progressive cognitive decline associated with Alzheimer's disease. However, the nature of the toxic Abeta species and its precise mechanism of action remain to be determined. It has been reported that the methionine residue at position 35 has a pivotal role to play in the toxicity of Abeta. We examined the effect of mutating the methionine to valine in Abeta42 (AbetaM35V). The neurotoxic activity of AbetaM35V on primary mouse neuronal cortical cells was enhanced, and this diminished cell viability occurred at an accelerated rate compared with Abeta42. AbetaM35V binds Cu2+ and produces similar amounts of H2O2 as Abeta42 in vitro, and the neurotoxic activity was attenuated by the H2O2 scavenger catalase. The increased toxicity of AbetaM35V was associated with increased binding of this mutated peptide to cortical cells. The M35V mutation altered the interaction between Abeta and copper in a lipid environment as shown by EPR analysis, which indicated that the valine substitution made the peptide less rigid in the bilayer region with a resulting higher affinity for the bilayer. Circular dichroism spectroscopy showed that both Abeta42 and AbetaM35V displayed a mixture of alpha-helical and beta-sheet conformations. These findings provide further evidence that the toxicity of Abeta is regulated by binding to neuronal cells.

In the interesting debate entitled "Challenging Views of Alzheimer's Disease II," we defended the position that factors such as oxygen, the single methionine residue of amyloid beta-peptide(1-42) [Abeta(1-42)], and redox metal ions were important for the oxidative stress and neurotoxic properties of this peptide that is critically involved in the pathogenesis of Alzheimer's disease. This brief review summarizes some of our findings relevant to the role of the single methionine residue of Abeta(1-42) in the oxidative stress and neurotoxic properties of this peptide.

Oxidative stress is associated with the neuropathology of Alzheimer's disease. We have previously shown that human Abeta has the ability to reduce Fe(III) and Cu(II) and produce hydrogen peroxide coupled with these metals, which is correlated with toxicity against primary neuronal cells. Cyclooxygenase (COX)-2 expression is linked to the progression and severity of pathology in AD. COX is a heme-containing enzyme that produces prostaglandins, and the enzyme also possesses peroxidase activity. Here we investigated the possibility of direct interaction between human Abeta and COX-2 being mediated by the peroxidase activity. Human Abeta formed dimers when it was reacted with COX-2 and hydrogen peroxide. Moreover, the peptide formed a cross-linked complex directly with COX-2. Such cross-linking was not observed with rat Abeta, and the sole tyrosine residue specific for human Abeta might therefore be the site of cross-linking. Similar complexes of Abeta and COX-2 were detected in post-mortem brain samples in greater amounts in AD tissue than in age-matched controls. COX-2-mediated cross-linking may inhibit Abeta catabolism and possibly generate toxic intracellular forms of oligomeric Abeta.

Studies on postmortem brains from Parkinson's patients reveal elevated iron in the substantia nigra (SN). Selective cell death in this brain region is associated with oxidative stress, which may be exacerbated by the presence of excess iron. Whether iron plays a causative role in cell death, however, is controversial. Here, we explore the effects of iron chelation via either transgenic expression of the iron binding protein ferritin or oral administration of the bioavailable metal chelator clioquinol (CQ) on susceptibility to the Parkinson's-inducing agent 1-methyl-4-phenyl-1,2,3,6-tetrapyridine (MPTP). Reduction in reactive iron by either genetic or pharmacological means was found to be well tolerated in animals in our studies and to result in protection against the toxin, suggesting that iron chelation may be an effective therapy for prevention and treatment of the disease.

Increased brain metal levels have been associated with normal aging and a variety of diseases, including Alzheimer's disease (AD). Copper and iron levels both show marked increases with age and may adversely interact with the amyloid-beta (Abeta) peptide causing its aggregation and the production of neurotoxic hydrogen peroxide (H(2)O(2)), contributing to the pathogenesis of AD. Amyloid precursor protein (APP) possesses copper/zinc binding sites in its amino-terminal domain and in the Abeta domain. Here we demonstrate that overexpression of the carboxyl-terminal fragment of APP, containing Abeta, results in significantly reduced copper and iron levels in transgenic mouse brain, while overexpression of the APP in Tg2576 transgenic mice results in significantly reduced copper, but not iron, levels prior to the appearance of amyloid neuropathology and throughout the lifespan of the mouse. Concomitant increases in brain manganese levels were observed with both transgenic strains. These findings, complemented by our previous findings of elevated copper levels in APP knock-out mice, support roles for APP and Abeta in physiological metal regulation.

β-Amyloid (Aβ) 1–42, implicated in the pathogenesis of Alzheimer's disease, forms an oligomeric complex that binds copper at a CuZn superoxide dismutase-like binding site. Aβ·Cu complexes generate neurotoxic H2O2 from O2 through Cu2+ reduction, but the reaction mechanism has been unclear. We now report that Aβ1–42, when binding up to 2 eq of Cu2+, generates the H2O2catalytically by recruiting biological reducing agents as substrates under conditions where the Cu2+ or reducing agents will not form H2O2 themselves. Cholesterol is an important substrate for this activity, as are vitamin C,l-DOPA, and dopamine (V maxfor dopamine = 34.5 nm/min, K m = 8.9 μm). The activity was inhibited by anti-Aβ antibodies, Cu2+ chelators, and Zn2+. Toxicity of Aβ in neuronal culture was consistent with catalytic H2O2 production. Aβ was not toxic in cell cultures in the absence of Cu2+, and dopamine (5 μm) markedly exaggerated the neurotoxicity of 200 nm Aβ1–42·Cu. Therefore, microregional catalytic H2O2 production, combined with the exhaustion of reducing agents, may mediate the neurotoxicity of Aβ in Alzheimer's disease, and inhibitors of this novel activity may be of therapeutic value.