Methionine-35 of Aβ(1–42): Importance for Oxidative Stress in Alzheimer Disease

Alzheimer disease (AD) is an age-related progressive neurodegenerative disorder. This devastating disease is characterized by the presence of senile plaques (SP), neurofibrillary tangles (NFTs), and loss of synapses. Amyloid beta-peptide 1–42 (Aβ(1–42)) is the main component of SP and is pivotal to AD pathogenesis. Brain of subjects with AD and arguably its earliest manifestation, mild cognitive impairment (MCI), demonstrate increased levels of oxidative stress markers. Our laboratory combined these two aspects of AD and MCI and proposed the Aβ(1–42)-associated free radical oxidative stress hypothesis to explain oxidative stress under which the MCI and AD brain exist and the loss of synapses in both disorders. A large number of in vitro and in vivo studies showed that Aβ causes protein oxidation, lipid peroxidation, reactive oxygen species formation, and cell death in neuronal and synaptosomal systems. Methionine located at residue 35 of Aβ(1–42) is an important contributor to the oxidative stress associated with this neurotoxic peptide. In this paper, we summarize studies involving Met-35 of Aβ(1–42). Understanding the role of the single methionine residue of Aβ(1–42) may help in understanding underlying disease mechanisms in AD and MCI

Amyloid \u3cem\u3eβ\u3c/em\u3e-Peptide (1–42)-Induced Oxidative Stress in Alzheimer Disease: Importance in Disease Pathogenesis and Progression

Significance: Alzheimer disease (AD) is an age-related neurodegenerative disease. AD is characterized by progressive cognitive impairment. One of the main histopathological hallmarks of AD brain is the presence of senile plaques (SPs) and another is elevated oxidative stress. The main component of SPs is amyloid beta-peptide (Aβ) that is derived from the proteolytic cleavage of amyloid precursor protein. Recent Advances: Recent studies are consistent with the notion that methionine present at 35 position of Aβ is critical to Aβ-induced oxidative stress and neurotoxicity. Further, we also discuss the signatures of oxidatively modified brain proteins, identified using redox proteomics approaches, during the progression of AD. Critical Issues: The exact relationships of the specifically oxidatively modified proteins in AD pathogenesis require additional investigation. Future Directions: Further studies are needed to address whether the therapies directed toward brain oxidative stress and oxidatively modified key brain proteins might help delay or prevent the progression of AD. Antioxid. Redox Signal. 19, 823–835

Redox Proteomics in Selected Neurodegenerative Disorders: From Its Infancy to Future Applications

Several studies demonstrated that oxidative damage is a characteristic feature of many neurodegenerative diseases. The accumulation of oxidatively modified proteins may disrupt cellular functions by affecting protein expression, protein turnover, cell signaling, and induction of apoptosis and necrosis, suggesting that protein oxidation could have both physiological and pathological significance. For nearly two decades, our laboratory focused particular attention on studying oxidative damage of proteins and how their chemical modifications induced by reactive oxygen species/reactive nitrogen species correlate with pathology, biochemical alterations, and clinical presentations of Alzheimer\u27s disease. This comprehensive article outlines basic knowledge of oxidative modification of proteins and lipids, followed by the principles of redox proteomics analysis, which also involve recent advances of mass spectrometry technology, and its application to selected age-related neurodegenerative diseases. Redox proteomics results obtained in different diseases and animal models thereof may provide new insights into the main mechanisms involved in the pathogenesis and progression of oxidative-stress-related neurodegenerative disorders. Redox proteomics can be considered a multifaceted approach that has the potential to provide insights into the molecular mechanisms of a disease, to find disease markers, as well as to identify potential targets for drug therapy. Considering the importance of a better understanding of the cause/effect of protein dysfunction in the pathogenesis and progression of neurodegenerative disorders, this article provides an overview of the intrinsic power of the redox proteomics approach together with the most significant results obtained by our laboratory and others during almost 10 years of research on neurodegenerative disorders since we initiated the field of redox proteomics

Abeta, oxidative stress in Alzheimer disease: Evidence based on proteomics studies

AbstractThe initiation and progression of Alzheimer disease (AD) is a complex process not yet fully understood. While many hypotheses have been provided as to the cause of the disease, the exact mechanisms remain elusive and difficult to verify. Proteomic applications in disease models of AD have provided valuable insights into the molecular basis of this disorder, demonstrating that on a protein level, disease progression impacts numerous cellular processes such as energy production, cellular structure, signal transduction, synaptic function, mitochondrial function, cell cycle progression, and proteasome function. Each of these cellular functions contributes to the overall health of the cell, and the dysregulation of one or more could contribute to the pathology and clinical presentation in AD. In this review, foci reside primarily on the amyloid β-peptide (Aβ) induced oxidative stress hypothesis and the proteomic studies that have been conducted by our laboratory and others that contribute to the overall understanding of this devastating neurodegenerative disease. This article is part of a Special Issue entitled: Misfolded Proteins, Mitochondrial Dysfunction, and Neurodegenerative Diseases

Heme oxygenase-1 posttranslational modifications in the brain of subjects with Alzheimer disease and mild cognitive impairment. Free Radic.

a b s t r a c t Alzheimer disease (AD) is a neurodegenerative disorder characterized by progressive cognitive impairment and neuropathology. Oxidative and nitrosative stress plays a principal role in the pathogenesis of AD. The induction of the heme oxygenase-1/biliverdin reductase-A (HO-1/BVR-A) system in the brain represents one of the earliest mechanisms activated by cells to counteract the noxious effects of increased reactive oxygen species and reactive nitrogen species. Although initially proposed as a neuroprotective system in AD brain, the HO-1/BVR-A pathophysiological features are under debate. We previously reported alterations in BVR activity along with decreased phosphorylation and increased oxidative/nitrosative posttranslational modifications in the brain of subjects with AD and those with mild cognitive impairment (MCI). Furthermore, other groups proposed the observed increase in HO-1 in AD brain as a possible neurotoxic mechanism. Here we provide new insights about HO-1 in the brain of subjects with AD and MCI, the latter condition being the transitional phase between normal aging and early AD. HO-1 protein levels were significantly increased in the hippocampus of AD subjects, whereas HO-2 protein levels were significantly decreased in both AD and MCI hippocampi. In addition, significant increases in Ser-residue phosphorylation together with increased oxidative posttranslational modifications were found in the hippocampus of AD subjects. Interestingly, despite the lack of oxidative stressinduced AD neuropathology in cerebellum, HO-1 demonstrated increased Ser-residue phosphorylation and oxidative posttranslational modifications in this brain area, suggesting HO-1 as a target of oxidative damage even in the cerebellum. The significance of these findings is profound and opens new avenues into the comprehension of the role of HO-1 in the pathogenesis of AD. & 2012 Elsevier Inc. All rights reserved. Introduction Increased oxidative and nitrosative stress represents one of the main mechanisms involved in the pathogenesis of neurodegenerative disorders such as Alzheimer disease (AD), which exhibits a large impairment of neuronal structure and molecular pathways due to oxidative stress-induced posttranslational modifications on both proteins and lipids AD is an age-related neurodegenerative disorder characterized histopathologically by the presence of senile plaques, neurofibrillary tangles (NFTs), and synapse loss in selected brain region

Redox proteomic analysis of carbonylated brain proteins in mild cognitive impairment and early Alzheimer's disease.

Abstract Previous studies indicated increased levels of protein oxidation in brain from subjects with Alzheimer's disease (AD), raising the question of whether oxidative damage is a late effect of neurodegeneration or precedes and contributes to the pathogenesis of AD. Hence, in the present study we used a parallel proteomic approach to identify oxidatively modified proteins in inferior parietal lobule (IPL) from subjects with mild cognitive impairment (MCI) and early stage-AD (EAD). By comparing to age-matched controls, we reasoned that such analysis could help in understanding potential mechanisms involved in upstream processes in AD pathogenesis. We have identified four proteins that showed elevated levels of protein carbonyls: carbonic anhydrase II (CA II), heat shock protein 70 (Hsp70), mitogen-activated protein kinase I (MAPKI), and syntaxin binding protein I (SBP1) in MCI IPL. In EAD IPL we identified three proteins: phosphoglycerate mutase 1 (PM1), glial fibrillary acidic protein, and fructose bisphospate aldolase C (FBA-C). Our results imply that some of the common targets of protein carbonylation correlated with AD neuropathology and suggest a possible involvement of protein modifications in the AD progression. Antioxid. Redox Signal. 12, 327-336

Doxorubicin-Induced Elevated Oxidative Stress and Neurochemical Alterations in Brain and Cognitive Decline: Protection by MESNA and Insights into Mechanisms of Chemotherapy-Induced Cognitive Impairment ( Chemobrain )

Chemotherapy-induced cognitive impairment (CICI) is now widely recognized as a real and too common complication of cancer chemotherapy experienced by an ever-growing number of cancer survivors. Previously, we reported that doxorubicin (Dox), a prototypical reactive oxygen species (ROS)-producing anti-cancer drug, results in oxidation of plasma proteins, including apolipoprotein A-I (ApoA-I) leading to tumor necrosis factor-alpha (TNF-α)-mediated oxidative stress in plasma and brain. We also reported that co-administration of the antioxidant drug, 2-mercaptoethane sulfonate sodium (MESNA), prevents Dox-induced protein oxidation and subsequent TNF-α elevation in plasma. In this study, we measured oxidative stress in both brain and plasma of Dox-treated mice both with and without MESNA. MESNA ameliorated Dox-induced oxidative protein damage in plasma, confirming our prior studies, and in a new finding led to decreased oxidative stress in brain. This study also provides further functional and biochemical evidence of the mechanisms of CICI. Using novel object recognition (NOR), we demonstrated the Dox administration resulted in memory deficits, an effect that was rescued by MESNA. Using hydrogen magnetic resonance imaging spectroscopy (H1-MRS) techniques, we demonstrated that Dox administration led to a dramatic decrease in choline-containing compounds assessed by (Cho)/creatine ratios in the hippocampus in mice. To better elucidate a potential mechanism for this MRS observation, we tested the activities of the phospholipase enzymes known to act on phosphatidylcholine (PtdCho), a key component of phospholipid membranes and a source of choline for the neurotransmitter, acetylcholine (ACh). The activities of both phosphatidylcholine-specific phospholipase C (PC-PLC) and phospholipase D were severely diminished following Dox administration. The activity of PC-PLC was preserved when MESNA was co-administered with Dox; however, PLD activity was not protected. This study is the first to demonstrate the protective effects of MESNA on Dox-related protein oxidation, cognitive decline, phosphocholine (PCho) levels, and PC-PLC activity in brain and suggests novel potential therapeutic targets and strategies to mitigate CICI

Plasma and Serum Proteins Bound to Nanoceria: Insights into Pathways by which Nanoceria May Exert Its Beneficial and Deleterious Effects \u3cem\u3eIn Vivo\u3c/em\u3e

Nanoceria (CeO2, cerium oxide nanoparticles) is proposed as a therapeutic for multiple disorders. In blood, nanoceria becomes protein-coated, changing its surface properties to yield a different presentation to cells. There is little information on the interaction of nanoceria with blood proteins. The current study is the first to report the proteomics identification of plasma and serum proteins adsorbed to nanoceria. The results identify a number of plasma and serum proteins interacting with nanoceria, proteins whose normal activities regulate numerous cell functions: antioxidant/detoxification, energy regulation, lipoproteins, signaling, complement, immune function, coagulation, iron homeostasis, proteolysis, inflammation, protein folding, protease inhibition, adhesion, protein/RNA degradation, and hormonal. The principal implications of this study are: 1) The protein corona may positively or negatively affect nanoceria cellular uptake, subsequent organ bioprocessing, and effects; and 2) Nanoceria adsorption may alter protein structure and function, including pro- and inflammatory effects. Consequently, prior to their use as therapeutic agents, better understanding of the effects of nanoceria protein coating is warranted

Rat Hippocampal Responses up to 90 Days After a Single Nanoceria Dose Extends a Hierarchical Oxidative Stress Model for Nanoparticle Toxicity

Ceria engineered nanomaterials (ENMs) have very promising commercial and therapeutic applications. Few reports address the effects of nanoceria in intact mammals, let alone long term exposure. This knowledge is essential to understand potential therapeutic applications of nanoceria in relation to its hazard assessment. The current study elucidates oxidative stress responses in the rat hippocampus 1 and 20 h, and 1, 7, 30 and 90 days following a single systemic infusion of 30 nm nanoceria. The results are incorporated into a previously described hierarchical oxidative stress (HOS) model. During the 1-20 h period, increases of the GSSG: GSH ratio and cytoprotective phase-II antioxidants were observed. During the 1-7 d period, cytoprotective phase-II antioxidants activities were inhibited with concomitant elevation of protein carbonyl (PC), 3-nitrotyrosine (3NT), heme oxygenase-1 (HO-1), cytokine IL-1β and the autophagy marker LC-3AB. At 30 day post ceria infusion, oxidative stress had its major impact. Phase-II enzyme activities were inhibited; concurrently PC, 3NT, HO-1 and Hsp70 levels were elevated along with augmentation of IL-1β, pro-apoptotic pro-caspase-3 and LC-3AB levels. This progress of escalating oxidative stress was reversed at 90 days when phase-II enzyme levels and activities were restored to normal levels, PC and 3NT levels were reduced to baseline, cytokine and pro-caspase-3 levels were suppressed, and cellular redox balance was restored in the rat hippocampus. This study demonstrates that a single administration of nanoceria induced oxidative stress that escalates to 30 days then terminates, in spite of the previously reported continued presence of nanoceria in peripheral organs. These results for the first time confirm in vivo the HOS model of response to ENM previously posited based on in vitro studies and extends this prior hierarchical oxidative stress model that described three tiers to a 4th tier, characterized by resolution of the oxidative stress and return to normal conditions