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Ekanayake RSK, Streltsov VA, Best SP, Chantler CT. Nanostructure and dynamics of N-truncated copper amyloid-β peptides from advanced X-ray absorption fine structure. IUCRJ 2024; 11:325-346. [PMID: 38602752 PMCID: PMC11067746 DOI: 10.1107/s2052252524001830] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/29/2023] [Accepted: 02/26/2024] [Indexed: 04/12/2024]
Abstract
An X-ray absorption spectroscopy (XAS) electrochemical cell was used to collect high-quality XAS measurements of N-truncated Cu:amyloid-β (Cu:Aβ) samples under near-physiological conditions. N-truncated Cu:Aβ peptide complexes contribute to oxidative stress and neurotoxicity in Alzheimer's patients' brains. However, the redox properties of copper in different Aβ peptide sequences are inconsistent. Therefore, the geometry of binding sites for the copper binding in Aβ4-8/12/16 was determined using novel advanced extended X-ray absorption fine structure (EXAFS) analysis. This enables these peptides to perform redox cycles in a manner that might produce toxicity in human brains. Fluorescence XAS measurements were corrected for systematic errors including defective-pixel data, monochromator glitches and dispersion of pixel spectra. Experimental uncertainties at each data point were measured explicitly from the point-wise variance of corrected pixel measurements. The copper-binding environments of Aβ4-8/12/16 were precisely determined by fitting XAS measurements with propagated experimental uncertainties, advanced analysis and hypothesis testing, providing a mechanism to pursue many similarly complex questions in bioscience. The low-temperature XAS measurements here determine that CuII is bound to the first amino acids in the high-affinity amino-terminal copper and nickel (ATCUN) binding motif with an oxygen in a tetragonal pyramid geometry in the Aβ4-8/12/16 peptides. Room-temperature XAS electrochemical-cell measurements observe metal reduction in the Aβ4-16 peptide. Robust investigations of XAS provide structural details of CuII binding with a very different bis-His motif and a water oxygen in a quasi-tetrahedral geometry. Oxidized XAS measurements of Aβ4-12/16 imply that both CuII and CuIII are accommodated in an ATCUN-like binding site. Hypotheses for these CuI, CuII and CuIII geometries were proven and disproven using the novel data and statistical analysis including F tests. Structural parameters were determined with an accuracy some tenfold better than literature claims of past work. A new protocol was also developed using EXAFS data analysis for monitoring radiation damage. This gives a template for advanced analysis of complex biosystems.
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Affiliation(s)
| | - Victor A. Streltsov
- School of Physics, University of Melbourne, Australia
- The Florey Institute of Neuroscience and Mental Health, University of Melbourne, Australia
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2
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Chandran S, Binninger D. Role of Oxidative Stress, Methionine Oxidation and Methionine Sulfoxide Reductases (MSR) in Alzheimer's Disease. Antioxidants (Basel) 2023; 13:21. [PMID: 38275641 PMCID: PMC10812627 DOI: 10.3390/antiox13010021] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2023] [Revised: 12/11/2023] [Accepted: 12/14/2023] [Indexed: 01/27/2024] Open
Abstract
A major contributor to dementia seen in aging is Alzheimer's disease (AD). Amyloid beta (Aβ), a main component of senile plaques (SPs) in AD, induces neuronal death through damage to cellular organelles and structures, caused by oxidation of important molecules such as proteins by reactive oxygen species (ROS). Hyperphosphorylation and accumulation of the protein tau in the microtubules within the brain also promote ROS production. Methionine, a residue of proteins, is particularly sensitive to oxidation by ROS. One of the enzyme systems that reverses the oxidative damage in mammalian cells is the enzyme system known as Methionine Sulfoxide Reductases (MSRs). The components of the MSR system, namely MSRA and MSRB, reduce oxidized forms of methionine (Met-(o)) in proteins back to methionine (Met). Furthermore, the MSRs scavenge ROS by allowing methionine residues in proteins to utilize their antioxidant properties. This review aims to improve the understanding of the role of the MSR system of enzymes in reducing cellular oxidative damage and AD pathogenesis, which may contribute to effective therapeutic approaches for AD by targeting the MSR system.
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Affiliation(s)
- Sanjana Chandran
- Department of Molecular and Integrative Physiology, University of Michigan Medical School, University of Michigan, Ann Arbor, MI 48109, USA;
| | - David Binninger
- Department of Biological Sciences, Charles E. Schmidt College of Science, Florida Atlantic University, Boca Raton, FL 33431, USA
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3
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Kuang S, Zhu B, Zhang J, Yang F, Wu B, Ding W, Yang L, Shen S, Liang SH, Mondal P, Kumar M, Tanzi RE, Zhang C, Chao H, Ran C. A Photolabile Curcumin-Diazirine Analogue Enables Phototherapy with Physically and Molecularly Produced Light for Alzheimer's Disease Treatment. Angew Chem Int Ed Engl 2023; 62:e202312519. [PMID: 37721455 PMCID: PMC10615883 DOI: 10.1002/anie.202312519] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2023] [Revised: 09/14/2023] [Accepted: 09/18/2023] [Indexed: 09/19/2023]
Abstract
The development of Alzheimer's disease (AD) drugs has recently witnessed substantial achievement. To further enhance the pool of drug candidates, it is crucial to explore non-traditional therapeutic avenues. In this study, we present the use of a photolabile curcumin-diazirine analogue, CRANAD-147, to induce changes in properties, structures (sequences), and neurotoxicity of amyloid beta (Aβ) species both in cells and in vivo. This manipulation was achieved through irradiation with LED light or molecularly generated light, dubbed as "molecular light", emitted by the chemiluminescence probe ADLumin-4. Next, aided by molecular chemiluminescence imaging, we demonstrated that the combination of CRANAD-147/LED or CRANAD-147/ADLumin-4 (molecular light) could effectively slow down the accumulation of Aβs in transgenic 5xFAD mice in vivo. Leveraging the remarkable tissue penetration capacity of molecular light, phototherapy employing the synergistic effect of a photolabile Aβ ligand and molecular light emerges as a promising alternative to conventional AD treatment interventions.
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Affiliation(s)
- Shi Kuang
- Athinoula A. Martinos Center for Biomedical Imaging, Department of Radiology, Massachusetts General Hospital, Harvard Medical School, Building 149, Charlestown, Boston, MA-02129, USA
| | - Biyue Zhu
- Athinoula A. Martinos Center for Biomedical Imaging, Department of Radiology, Massachusetts General Hospital, Harvard Medical School, Building 149, Charlestown, Boston, MA-02129, USA
| | - Jing Zhang
- Athinoula A. Martinos Center for Biomedical Imaging, Department of Radiology, Massachusetts General Hospital, Harvard Medical School, Building 149, Charlestown, Boston, MA-02129, USA
| | - Fan Yang
- Athinoula A. Martinos Center for Biomedical Imaging, Department of Radiology, Massachusetts General Hospital, Harvard Medical School, Building 149, Charlestown, Boston, MA-02129, USA
| | - Bo Wu
- Athinoula A. Martinos Center for Biomedical Imaging, Department of Radiology, Massachusetts General Hospital, Harvard Medical School, Building 149, Charlestown, Boston, MA-02129, USA
| | - Weihua Ding
- MGH Center for Translational Pain Research, Department of Anesthesia, Critical Care and Pain Medicine, Massachusetts General Hospital, Harvard Medical School, Boston, MA-02129, USA
| | - Liuyue Yang
- MGH Center for Translational Pain Research, Department of Anesthesia, Critical Care and Pain Medicine, Massachusetts General Hospital, Harvard Medical School, Boston, MA-02129, USA
| | - Shiqian Shen
- MGH Center for Translational Pain Research, Department of Anesthesia, Critical Care and Pain Medicine, Massachusetts General Hospital, Harvard Medical School, Boston, MA-02129, USA
| | - Seven H Liang
- Department of Radiology, Massachusetts General Hospital, Harvard Medical School, Boston, MA-02114, USA
| | - Prasenjit Mondal
- Genetics and Aging Research Unit, McCance Center for Brain Health, MassGeneral Institute for Neurodegenerative Disease, Department of Neurology, Massachusetts General Hospital, Harvard Medical School, Boston, MA-02129, USA
| | - Mohanraja Kumar
- Department of Chemistry, Massachusetts Institute of Technology, Cambridge, MA-02139, USA
| | - Rudolph E Tanzi
- Genetics and Aging Research Unit, McCance Center for Brain Health, MassGeneral Institute for Neurodegenerative Disease, Department of Neurology, Massachusetts General Hospital, Harvard Medical School, Boston, MA-02129, USA
| | - Can Zhang
- Genetics and Aging Research Unit, McCance Center for Brain Health, MassGeneral Institute for Neurodegenerative Disease, Department of Neurology, Massachusetts General Hospital, Harvard Medical School, Boston, MA-02129, USA
| | - Hui Chao
- MOE Key Laboratory of Bioinorganic and Synthetic Chemistry, School of Chemistry, Sun Yat-Sen University, Guangzhou, 510006, P. R. China
| | - Chongzhao Ran
- Athinoula A. Martinos Center for Biomedical Imaging, Department of Radiology, Massachusetts General Hospital, Harvard Medical School, Building 149, Charlestown, Boston, MA-02129, USA
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4
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Mañucat-Tan NB, Chowdhury A, Cataldi R, Abdullah RZ, Kumita JR, Wyatt AR. Hypochlorite-induced oxidation promotes aggregation and reduces toxicity of amyloid beta 1-42. Redox Biol 2023; 63:102736. [PMID: 37216700 DOI: 10.1016/j.redox.2023.102736] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2023] [Revised: 05/05/2023] [Accepted: 05/07/2023] [Indexed: 05/24/2023] Open
Abstract
Exacerbated hypochlorite (OCl-) production is linked to neurodegenerative processes, but there is growing evidence that lower levels of hypochlorite activity are important to protein homeostasis. In this study we characterise the effects of hypochlorite on the aggregation and toxicity of amyloid beta peptide 1-42 (Aβ1-42), a major component of amyloid plaques that form in the brain in Alzheimer's disease. Our results demonstrate that treatment with hypochlorite promotes the formation of Aβ1-42 assemblies ≥100 kDa that have reduced surface exposed hydrophobicity compared to the untreated peptide. This effect is the result of the oxidation of Aβ1-42 at a single site as determined by mass spectrometry analysis. Although treatment with hypochlorite promotes the aggregation of Aβ1-42, the solubility of the peptide is enhanced and amyloid fibril formation is inhibited as assessed by filter trap assay, thioflavin T assay and transmission electron microscopy. The results of in vitro assays using SH-SY5Y neuroblastoma cells show that pre-treatment of Aβ1-42 with a sub-stoichiometric amount of hypochlorite substantially reduces its toxicity. The results of flow cytometry analysis and internalisation assays indicate that hypochlorite-induced modification of Aβ1-42 reduces its toxicity via at least two-distinct mechanism, reducing the total binding of Aβ1-42 to the surface of cells and facilitating the cell surface clearance of Aβ1-42 to lysosomes. Our data is consistent with a model in which tightly regulated production of hypochlorite in the brain is protective against Aβ-induced toxicity.
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Affiliation(s)
- Noralyn B Mañucat-Tan
- Flinders Health and Medical Research Institute, College of Medicine and Public Health, Flinders University, SA, Australia, 5048
| | - Ashfaq Chowdhury
- Yusef Hamied Department of Chemistry, University of Cambridge, Lensfield Road, Cambridge, CB2 1EW, UK
| | - Rodrigo Cataldi
- Yusef Hamied Department of Chemistry, University of Cambridge, Lensfield Road, Cambridge, CB2 1EW, UK
| | - Rafaa Zeineddine Abdullah
- Illawarra Health and Medical Research Institute and School of Biological Sciences, University of Wollongong, NSW, Australia, 2500
| | - Janet R Kumita
- Yusef Hamied Department of Chemistry, University of Cambridge, Lensfield Road, Cambridge, CB2 1EW, UK; Department of Pharmacology, University of Cambridge, Tennis Court Road, Cambridge, CB2 1PD, UK.
| | - Amy R Wyatt
- Flinders Health and Medical Research Institute, College of Medicine and Public Health, Flinders University, SA, Australia, 5048.
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Pluta R, Kiś J, Januszewski S, Jabłoński M, Czuczwar SJ. Cross-Talk between Amyloid, Tau Protein and Free Radicals in Post-Ischemic Brain Neurodegeneration in the Form of Alzheimer’s Disease Proteinopathy. Antioxidants (Basel) 2022; 11:antiox11010146. [PMID: 35052650 PMCID: PMC8772936 DOI: 10.3390/antiox11010146] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2021] [Revised: 01/05/2022] [Accepted: 01/09/2022] [Indexed: 02/04/2023] Open
Abstract
Recent years have seen remarkable progress in research into free radicals oxidative stress, particularly in the context of post-ischemic recirculation brain injury. Oxidative stress in post-ischemic tissues violates the integrity of the genome, causing DNA damage, death of neuronal, glial and vascular cells, and impaired neurological outcome after brain ischemia. Indeed, it is now known that DNA damage and repair play a key role in post-stroke white and gray matter remodeling, and restoring the integrity of the blood-brain barrier. This review will present one of the newly characterized mechanisms that emerged with genomic and proteomic development that led to brain ischemia to a new level of post-ischemic neuropathological mechanisms, such as the presence of amyloid plaques and the development of neurofibrillary tangles, which further exacerbate oxidative stress. Finally, we hypothesize that modified amyloid and the tau protein, along with the oxidative stress generated, are new key elements in the vicious circle important in the development of post-ischemic neurodegeneration in a type of Alzheimer’s disease proteinopathy.
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Affiliation(s)
- Ryszard Pluta
- Laboratory of Ischemic and Neurodegenerative Brain Research, Mossakowski Medical Research Institute, Polish Academy of Sciences, Pawińskiego 5 Str., 02-106 Warsaw, Poland;
- Correspondence: ; Tel.: +48-22-608-6540
| | - Jacek Kiś
- Department of Urology, 1st Military Clinical Hospital with the Outpatient Clinic, Al. Racławickie 23, 20-049 Lublin, Poland;
| | - Sławomir Januszewski
- Laboratory of Ischemic and Neurodegenerative Brain Research, Mossakowski Medical Research Institute, Polish Academy of Sciences, Pawińskiego 5 Str., 02-106 Warsaw, Poland;
| | - Mirosław Jabłoński
- Department of Rehabilitation and Orthopedics, Medical University of Lublin, Jaczewskiego 8 Str., 20-090 Lublin, Poland;
| | - Stanisław J. Czuczwar
- Department of Pathophysiology, Medical University of Lublin, Jaczewskiego 8b Str., 20-090 Lublin, Poland;
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6
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Moskovitz J, Smith A. Methionine sulfoxide and the methionine sulfoxide reductase system as modulators of signal transduction pathways: a review. Amino Acids 2021; 53:1011-1020. [PMID: 34145481 DOI: 10.1007/s00726-021-03020-9] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2021] [Accepted: 06/14/2021] [Indexed: 01/16/2023]
Abstract
Methionine oxidation and reduction is a common phenomenon occurring in biological systems under both physiological and oxidative-stress conditions. The levels of methionine sulfoxide (MetO) are dependent on the redox status in the cell or organ, and they are usually elevated under oxidative-stress conditions, aging, inflammation, and oxidative-stress related diseases. MetO modification of proteins may alter their function or cause the accumulation of toxic proteins in the cell/organ. Accordingly, the regulation of the level of MetO is mediated through the ubiquitous and evolutionary conserved methionine sulfoxide reductase (Msr) system and its associated redox molecules. Recent published research has provided new evidence for the involvement of free MetO or protein-bound MetO of specific proteins in several signal transduction pathways that are important for cellular function. In the current review, we will focus on the role of MetO in specific signal transduction pathways of various organisms, with relation to their physiological contexts, and discuss the contribution of the Msr system to the regulation of the observed MetO effect.
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Affiliation(s)
- Jackob Moskovitz
- Department of Pharmacology and Toxicology, School of Pharmacy, University of Kansas, Lawrence, KS, 66045, USA.
| | - Adam Smith
- Department of Pharmacology and Toxicology, School of Pharmacy, University of Kansas, Lawrence, KS, 66045, USA
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7
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Methionine metabolism in chronic liver diseases: an update on molecular mechanism and therapeutic implication. Signal Transduct Target Ther 2020; 5:280. [PMID: 33273451 PMCID: PMC7714782 DOI: 10.1038/s41392-020-00349-7] [Citation(s) in RCA: 39] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2020] [Revised: 08/30/2020] [Accepted: 09/18/2020] [Indexed: 02/06/2023] Open
Abstract
As one of the bicyclic metabolic pathways of one-carbon metabolism, methionine metabolism is the pivot linking the folate cycle to the transsulfuration pathway. In addition to being a precursor for glutathione synthesis, and the principal methyl donor for nucleic acid, phospholipid, histone, biogenic amine, and protein methylation, methionine metabolites can participate in polyamine synthesis. Methionine metabolism disorder can aggravate the damage in the pathological state of a disease. In the occurrence and development of chronic liver diseases (CLDs), changes in various components involved in methionine metabolism can affect the pathological state through various mechanisms. A methionine-deficient diet is commonly used for building CLD models. The conversion of key enzymes of methionine metabolism methionine adenosyltransferase (MAT) 1 A and MAT2A/MAT2B is closely related to fibrosis and hepatocellular carcinoma. In vivo and in vitro experiments have shown that by intervening related enzymes or downstream metabolites to interfere with methionine metabolism, the liver injuries could be reduced. Recently, methionine supplementation has gradually attracted the attention of many clinical researchers. Most researchers agree that adequate methionine supplementation can help reduce liver damage. Retrospective analysis of recently conducted relevant studies is of profound significance. This paper reviews the latest achievements related to methionine metabolism and CLD, from molecular mechanisms to clinical research, and provides some insights into the future direction of basic and clinical research.
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8
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Cioffi F, Adam RHI, Broersen K. Molecular Mechanisms and Genetics of Oxidative Stress in Alzheimer's Disease. J Alzheimers Dis 2020; 72:981-1017. [PMID: 31744008 PMCID: PMC6971833 DOI: 10.3233/jad-190863] [Citation(s) in RCA: 102] [Impact Index Per Article: 25.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
Alzheimer’s disease is the most common neurodegenerative disorder that can cause dementia in elderly over 60 years of age. One of the disease hallmarks is oxidative stress which interconnects with other processes such as amyloid-β deposition, tau hyperphosphorylation, and tangle formation. This review discusses current thoughts on molecular mechanisms that may relate oxidative stress to Alzheimer’s disease and identifies genetic factors observed from in vitro, in vivo, and clinical studies that may be associated with Alzheimer’s disease-related oxidative stress.
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Affiliation(s)
- Federica Cioffi
- Nanobiophysics Group, Technical Medical Centre, Faculty of Science and Technology, University of Twente, Enschede, The Netherlands
| | - Rayan Hassan Ibrahim Adam
- Nanobiophysics Group, Technical Medical Centre, Faculty of Science and Technology, University of Twente, Enschede, The Netherlands
| | - Kerensa Broersen
- Applied Stem Cell Technologies, Technical Medical Centre, Faculty of Science and Technology, University of Twente, Enschede, The Netherlands
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9
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Pilkington AW, Donohoe GC, Akhmedov NG, Ferrebee T, Valentine SJ, Legleiter J. Hydrogen Peroxide Modifies Aβ-Membrane Interactions with Implications for Aβ 40 Aggregation. Biochemistry 2019; 58:2893-2905. [PMID: 31187978 DOI: 10.1021/acs.biochem.9b00233] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
Alzheimer's disease (AD) is pathologically characterized by the formation of extracellular senile plaques, predominately comprised of aggregated β-amyloid (Aβ), deposited in the brain. Aβ aggregation can result in a myriad of distinct aggregate species, from soluble oligomers to insoluble fibrils. Aβ strongly interacts with membranes, which can be linked to a variety of potential toxic mechanisms associated with AD. Oxidative damage accompanies the formation of Aβ aggregates, with a 10-50% proportion of Aβ aggregates being oxidized in vivo. Hydrogen peroxide (H2O2) is a reactive oxygen species implicated in a number of neurodegenerative diseases. Recent evidence has demonstrated that the H2O2 concentration fluctuates rapidly in the brain, resulting in large concentration spikes, especially in the synaptic cleft. Here, the impact of environmental H2O2 on Aβ aggregation in the presence and absence of lipid membranes is investigated. Aβ40 was exposed to H2O2, resulting in the selective oxidation of methionine 35 (Met35) to produce Aβ40Met35[O]. While oxidation mildly reduced the rate of Aβ aggregation and produced a distinct fibril morphology at high H2O2 concentrations, H2O2 had a much more pronounced impact on Aβ aggregation in the presence of total brain lipid extract vesicles. The impact of H2O2 on Aβ aggregation in the presence of lipids was associated with a reduced affinity of Aβ for the vesicle surface. However, this reduced vesicle affinity was predominately associated with lipid peroxidation rather than Aβ oxidation.
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Affiliation(s)
- Albert W Pilkington
- The C. Eugene Bennett Department of Chemistry , West Virginia University , 217 Clark Hall , Morgantown , West Virginia 26506 , United States
| | - Gregory C Donohoe
- The C. Eugene Bennett Department of Chemistry , West Virginia University , 217 Clark Hall , Morgantown , West Virginia 26506 , United States
| | - Novruz G Akhmedov
- The C. Eugene Bennett Department of Chemistry , West Virginia University , 217 Clark Hall , Morgantown , West Virginia 26506 , United States
| | - Timothy Ferrebee
- The C. Eugene Bennett Department of Chemistry , West Virginia University , 217 Clark Hall , Morgantown , West Virginia 26506 , United States
| | - Stephen J Valentine
- The C. Eugene Bennett Department of Chemistry , West Virginia University , 217 Clark Hall , Morgantown , West Virginia 26506 , United States
| | - Justin Legleiter
- The C. Eugene Bennett Department of Chemistry , West Virginia University , 217 Clark Hall , Morgantown , West Virginia 26506 , United States.,Blanchette Rockefeller Neurosciences Institutes , West Virginia University , 1 Medical Center Drive , P.O. Box 9303, Morgantown , West Virginia 26505 , United States.,Department of Neuroscience , West Virginia University , 1 Medical Center Drive , P.O. Box 9303, Morgantown , West Virginia 26505 , United States
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10
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Leri M, Natalello A, Bruzzone E, Stefani M, Bucciantini M. Oleuropein aglycone and hydroxytyrosol interfere differently with toxic Aβ 1-42 aggregation. Food Chem Toxicol 2019; 129:1-12. [PMID: 30995514 DOI: 10.1016/j.fct.2019.04.015] [Citation(s) in RCA: 42] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2019] [Revised: 04/08/2019] [Accepted: 04/10/2019] [Indexed: 12/18/2022]
Abstract
Oleuropein aglycone (OleA), the most abundant polyphenol in extra virgin olive oil (EVOO), and Hydroxythyrosol (HT), the OleA main metabolite, have attracted our interest due to their multitarget effects, including the interference with amyloid aggregation path. However, the mechanistic details of their anti-amyloid effect are not known yet. We report here a broad biophysical approach and cell biology techniques that enabled us to characterize the different molecular mechanisms by which OleA and HT modulate the Aβ1-42 fibrillation, a main histopathological feature of Alzheimer's disease (AD). In particular, OleA prevents the growth of toxic Aβ1-42 oligomers and blocks their successive growth into mature fibrils following its interaction with the peptide N-terminus, while HT speeds up harmless fibril formation. Our data demonstrate that, by stabilizing oligomers and fibrils, both polyphenols reduce their seeding activity and aggregate/membrane interaction on human neuroblastoma SH-SY5Y cells. These findings highlight the great potential of EVOO polyphenols and offer the possibility to validate and to optimize their use for possible AD prevention and therapy.
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Affiliation(s)
- Manuela Leri
- Department of Biomedical, Experimental and Clinical Sciences 'Mario Serio', University of Florence, Viale Morgagni 50 - 50134, Florence, Italy; Department of Neuroscience, Psychology, Area of Medicine and Health of the Child of the University of Florence, Viale Pieraccini, 6 - 50139 Florence, Italy.
| | - Antonino Natalello
- Department of Biotechnology and Biosciences, University of Milano Bicocca, Piazza della Scienza 2, 20126, Milano, Italy.
| | - Elena Bruzzone
- Department of Biomedical, Experimental and Clinical Sciences 'Mario Serio', University of Florence, Viale Morgagni 50 - 50134, Florence, Italy.
| | - Massimo Stefani
- Department of Biomedical, Experimental and Clinical Sciences 'Mario Serio', University of Florence, Viale Morgagni 50 - 50134, Florence, Italy; Interuniversity Center for the Study of Neurodegenerative Diseases (CIMN), Florence, Italy.
| | - Monica Bucciantini
- Department of Biomedical, Experimental and Clinical Sciences 'Mario Serio', University of Florence, Viale Morgagni 50 - 50134, Florence, Italy; Interuniversity Center for the Study of Neurodegenerative Diseases (CIMN), Florence, Italy.
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11
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Islam BU, Jabir NR, Tabrez S. The role of mitochondrial defects and oxidative stress in Alzheimer's disease. J Drug Target 2019; 27:932-942. [PMID: 30775938 DOI: 10.1080/1061186x.2019.1584808] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
Alzheimer's disease (AD) is a complex, progressive, and irreversible neurodegenerative disorder. Recent reports suggest that it affects more than 36 million people worldwide and accounts 60-80% of all cases of dementia. It is characterised by aberrations of multiple interactive systems and pathways, which ultimately lead to memory loss and cognitive dysfunction. The exact mechanisms and initial triggering factors that underpin the known pathological defects in AD remain to be fully elucidated. In addition, an effective treatment strategy to reduce the progression of AD is yet to be achieved. In the light of above-mentioned facts, our article deals with the exploration of the mitochondrial defect and oxidative stress leading to this devastating disease. In this communication, we have highlighted specific mitochondrial and antioxidant-directed approach to ameliorate and manage AD. Nonetheless, new approaches should also be investigated that could tackle various molecular events involved in AD pathogenicity.
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Affiliation(s)
- Badar Ul Islam
- a Department of Biochemistry, J N Medical College, Faculty of Medicine, Aligarh Muslim University , Aligarh , India
| | - Nasimudeen R Jabir
- b King Fahd Medical Research Center, King Abdulaziz University , Jeddah , Saudi Arabia.,c Department of Medical Laboratory Technology, Faculty of Applied Medical Sciences, King Abdulaziz University , Jeddah , Saudi Arabia
| | - Shams Tabrez
- b King Fahd Medical Research Center, King Abdulaziz University , Jeddah , Saudi Arabia.,c Department of Medical Laboratory Technology, Faculty of Applied Medical Sciences, King Abdulaziz University , Jeddah , Saudi Arabia
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12
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Streltsov VA, Ekanayake RSK, Drew SC, Chantler CT, Best SP. Structural Insight into Redox Dynamics of Copper Bound N-Truncated Amyloid-β Peptides from in Situ X-ray Absorption Spectroscopy. Inorg Chem 2018; 57:11422-11435. [PMID: 30169035 DOI: 10.1021/acs.inorgchem.8b01255] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
X-ray absorption spectroscopy of CuII amyloid-β peptide (Aβ) under in situ electrochemical control (XAS-EC) has allowed elucidation of the redox properties of CuII bound to truncated peptide forms. The Cu binding environment is significantly different for the Aβ1-16 and the N-truncated Aβ4-9, Aβ4-12, and Aβ4-16 (Aβ4-9/12/16) peptides, where the N-truncated sequence (F4R5H6) provides the high-affinity amino-terminal copper nickel (ATCUN) binding motif. Low temperature (ca. 10 K) XAS measurements show the adoption of identical CuII ATCUN-type binding sites (CuIIATCUN) by the first three amino acids (FRH) and a longer-range interaction modeled as an oxygen donor ligand, most likely water, to give a tetragonal pyramid geometry in the Aβ4-9/12/16 peptides not previously reported. Both XAS-EC and EPR measurements show that CuII:Aβ4-16 can be reduced at mildly reducing potentials, similar to that of CuII:Aβ1-16. Reduction of peptides lacking the H13H14 residues, CuII:Aβ4-9/12, require far more forcing conditions, with metallic copper the only metal-based reduction product. The observations suggest that reduction of CuIIATCUN species at mild potentials is possible, although the rate of reduction is significantly enhanced by involvement of H13H14. XAS-EC analysis reveals that, following reduction, the peptide acts as a terdentate ligand to CuI (H13, H14 together with the linking amide oxygen atom). Modeling of the EXAFS is most consistent with coordination of an additional water oxygen atom to give a quasi-tetrahedral geometry. XAS-EC analysis of oxidized CuII:Aβ4-12/16 gives structural parameters consistent with crystallographic data for a five-coordinate CuIII complex and the CuIIATCUN complex. The structural results suggest that CuII and the oxidation product are both accommodated in an ATCUN-like binding site.
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Affiliation(s)
- Victor A Streltsov
- Florey Department of Neuroscience and Mental Health , The University of Melbourne , Melbourne , Australia.,School of Physics , The University of Melbourne , Melbourne , Australia
| | | | - Simon C Drew
- Department of Medicine (Royal Melbourne Hospital) , The University of Melbourne , Melbourne , Australia
| | | | - Stephen P Best
- School of Chemistry , The University of Melbourne , Melbourne , Australia
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Cheignon C, Hureau C, Collin F. Real-time evolution of Aβ 40 metal-catalyzed oxidation reveals Asp1 as the main target and a dependence on metal binding site. Inorganica Chim Acta 2018. [DOI: 10.1016/j.ica.2017.07.031] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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14
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The Role of Free Radicals in Autophagy Regulation: Implications for Ageing. OXIDATIVE MEDICINE AND CELLULAR LONGEVITY 2018; 2018:2450748. [PMID: 29682156 PMCID: PMC5846360 DOI: 10.1155/2018/2450748] [Citation(s) in RCA: 41] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/21/2017] [Revised: 01/05/2018] [Accepted: 01/16/2018] [Indexed: 12/19/2022]
Abstract
Reactive oxygen and nitrogen species (ROS and RNS, resp.) have been traditionally perceived solely as detrimental, leading to oxidative damage of biological macromolecules and organelles, cellular demise, and ageing. However, recent data suggest that ROS/RNS also plays an integral role in intracellular signalling and redox homeostasis (redoxtasis), which are necessary for the maintenance of cellular functions. There is a complex relationship between cellular ROS/RNS content and autophagy, which represents one of the major quality control systems in the cell. In this review, we focus on redox signalling and autophagy regulation with a special interest on ageing-associated changes. In the last section, we describe the role of autophagy and redox signalling in the context of Alzheimer's disease as an example of a prevalent age-related disorder.
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Spahn C, Wermann M, Eichentopf R, Hause G, Schlenzig D, Schilling S. Purification of recombinant Aβ(1-42) and pGlu-Aβ(3-42) using preparative SDS-PAGE. Electrophoresis 2017; 38:2042-2049. [PMID: 28510356 DOI: 10.1002/elps.201700154] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2017] [Revised: 05/11/2017] [Accepted: 05/11/2017] [Indexed: 11/10/2022]
Abstract
Recombinant expression and purification of amyloid peptides represents a common basis for investigating the molecular mechanisms of amyloid formation and toxicity. However, the isolation of the recombinant peptides is hampered by inefficient separation from contaminants such as the fusion protein required for efficient expression in E. coli. Here, we present a new approach for the isolation of highly purified Aβ(1-42) and pGlu-Aβ(3-42), which is based on a separation using preparative SDS-PAGE. The method relies on the purification of the Aβ fusion protein by affinity chromatography followed by preparative SDS-PAGE under reducing conditions and subsequent removal of detergents by precipitation. The application of preparative SDS-PAGE represents the key step to isolate highly pure recombinant Aβ, which has been applied for characterization of aggregation and toxicity. Thereby, the yield of the purification strategy was >60%. To the best of our knowledge, this is the first description of an electrophoresis-based method for purification of a recombinant Aβ peptide. Therefore, the method might be of interest for isolation of other amyloid peptides, which are critical for conventional purification strategies due to their aggregation propensity.
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Affiliation(s)
- Claudia Spahn
- Fraunhofer Institute for Cell Therapy and Immunology, Department for Drug Design and Target Validation (IZI-MWT), Halle, Germany
| | - Michael Wermann
- Fraunhofer Institute for Cell Therapy and Immunology, Department for Drug Design and Target Validation (IZI-MWT), Halle, Germany
| | - Rico Eichentopf
- Fraunhofer Institute for Cell Therapy and Immunology, Department for Drug Design and Target Validation (IZI-MWT), Halle, Germany
| | - Gerd Hause
- Martin-Luther University Halle-Wittenberg, Halle, Germany
| | - Dagmar Schlenzig
- Fraunhofer Institute for Cell Therapy and Immunology, Department for Drug Design and Target Validation (IZI-MWT), Halle, Germany
| | - Stephan Schilling
- Fraunhofer Institute for Cell Therapy and Immunology, Department for Drug Design and Target Validation (IZI-MWT), Halle, Germany
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Carelli-Alinovi C, Misiti F. Methionine 35 sulphoxide reduces toxicity of Aβ in red blood cell. Eur J Clin Invest 2017; 47:314-321. [PMID: 28177519 DOI: 10.1111/eci.12735] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/04/2016] [Accepted: 02/04/2017] [Indexed: 12/11/2022]
Abstract
BACKGROUND The oxidation of methionine residue in position 35 of Ab to sulphoxide (Ab-sulphoxide) has the ability to deeply modify wild-type Ab 1-42 (Ab) neurotoxic action. Our previous studies suggest that in nucleated cells, lower toxicity of Ab-sulphoxide might result not from structural alteration, but from elevation of methionine sulphoxide reductase A (MsrA) activity and mRNA levels. DESIGN On this basis, we hypothesised that red blood cell (RBC), a cell devoid almost completely of MsrA activity, shares with nucleated cells an antioxidant system induced by methionine 35 sulphoxide, responsible for the lower toxicity of Ab-sulphoxide in RBC. (Results) Supporting this hypothesis, we found that the low toxicity of Ab-sulphoxide in RBC correlated with pentose phosphate pathway (PPP) flux increase, and this event was associated with a low level of methionine oxidation in total proteins. None of these effects were observed when cells were exposed to Ab native. DISCUSSION These results outline the importance of the redox state of methionine 35 in the modulation of Ab-mediated events and suggest an important protective role for PPP in RBC of patients affected by Alzheimer's disease.
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Affiliation(s)
- Cristiana Carelli-Alinovi
- School of Medicine, Biochemistry and Clinical Biochemistry Institute, Catholic University, Rome, Italy
| | - Francesco Misiti
- Human Sciences, Society and Health Department, University of Cassino and Southern Lazio, Cassino, Italy
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Gu M, Viles JH. Methionine oxidation reduces lag-times for amyloid-β(1-40) fiber formation but generates highly fragmented fibers. BIOCHIMICA ET BIOPHYSICA ACTA-PROTEINS AND PROTEOMICS 2016; 1864:1260-1269. [PMID: 27108954 DOI: 10.1016/j.bbapap.2016.04.009] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/07/2016] [Accepted: 04/19/2016] [Indexed: 01/06/2023]
Abstract
Oxidative stress and the formation of amyloid plaques containing amyloid-β (Aβ) peptides are two key hallmarks of Alzheimer's disease. A proportion of methionine (Met) at position 35 within Aβ is oxidized to methionine sulphoxide (Met(OX)) within the Alzheimer's plaques. These oxidative processes may be the key to understanding the early stages of Alzheimer's disease. In vitro oxidation of Aβ, by the physiological oxidant H2O2, was monitored using (1)H NMR and mass spectrometry. Here we investigate the effect of Aβ methionine oxidation on fiber formation kinetics and morphology using the amyloid specific fluorescence dye Thioflavin T (ThT) and Transmission Electron Microscopy (TEM). Methionine oxidation reduces the total amount of fibers generated for both dominant forms of Aβ, however there are marked differences in the effect of Met(OX) between Aβ(1-40) and Aβ(1-42). Surprisingly the presence of Met(OX) reduces lag-times for Aβ(1-40) fiber formation but extends lag-times for Aβ(1-42). TEM indicates a change in fiber morphology with a pronounced reduction in fiber length for both methionine oxidized Aβ(1-40) and Aβ(1-42). In contrast, the morphology of preformed amyloid fibers is largely unaffected by the presence of H2O2. Our studies suggest that methionine oxidation promotes highly fragmented fiber assemblies of Aβ. Oxidative stress associated with Alzheimer's disease can cause oxidation of methionine within Aβ and this in turn will influence the complex assembly of Aβ monomer into amyloid fibers, which is likely to impact Aβ toxicity.
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Affiliation(s)
- Miao Gu
- School of Biological and Chemical Sciences, Queen Mary, University of London, Mile End Road, London E1 4NS, United Kingdom
| | - John H Viles
- School of Biological and Chemical Sciences, Queen Mary, University of London, Mile End Road, London E1 4NS, United Kingdom
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Moskovitz J, Du F, Bowman CF, Yan SS. Methionine sulfoxide reductase A affects β-amyloid solubility and mitochondrial function in a mouse model of Alzheimer's disease. Am J Physiol Endocrinol Metab 2016; 310:E388-93. [PMID: 26786779 PMCID: PMC4796266 DOI: 10.1152/ajpendo.00453.2015] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/19/2015] [Accepted: 01/08/2016] [Indexed: 12/22/2022]
Abstract
Accumulation of oxidized proteins, and especially β-amyloid (Aβ), is thought to be one of the common causes of Alzheimer's disease (AD). The current studies determine the effect of an in vivo methionine sulfoxidation of Aβ through ablation of the methionine sulfoxide reductase A (MsrA) in a mouse model of AD, a mouse that overexpresses amyloid precursor protein (APP) and Aβ in neurons. Lack of MsrA fosters the formation of methionine sulfoxide in proteins, and thus its ablation in the AD-mouse model will increase the formation of methionine sulfoxide in Aβ. Indeed, the novel MsrA-deficient APP mice (APP(+)/MsrAKO) exhibited higher levels of soluble Aβ in brain compared with APP(+) mice. Furthermore, mitochondrial respiration and the activity of cytochrome c oxidase were compromised in the APP(+)/MsrAKO compared with control mice. These results suggest that lower MsrA activity modifies Aβ solubility properties and causes mitochondrial dysfunction, and augmenting its activity may be beneficial in delaying AD progression.
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Affiliation(s)
- Jackob Moskovitz
- Department of Pharmacology and Toxicology, School of Pharmacy, University of Kansas, Lawrence, Kansas
| | - Fang Du
- Department of Pharmacology and Toxicology, School of Pharmacy, University of Kansas, Lawrence, Kansas
| | - Connor F Bowman
- Department of Pharmacology and Toxicology, School of Pharmacy, University of Kansas, Lawrence, Kansas
| | - Shirley S Yan
- Department of Pharmacology and Toxicology, School of Pharmacy, University of Kansas, Lawrence, Kansas
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Carelli-Alinovi C, Ficarra S, Russo AM, Giunta E, Barreca D, Galtieri A, Misiti F, Tellone E. Involvement of acetylcholinesterase and protein kinase C in the protective effect of caffeine against β-amyloid-induced alterations in red blood cells. Biochimie 2016; 121:52-9. [DOI: 10.1016/j.biochi.2015.11.022] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2015] [Accepted: 11/22/2015] [Indexed: 02/04/2023]
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Wu Y, Xie G, Xu Y, Ma L, Tong C, Fan D, Du F, Yu H. PEP-1-MsrA ameliorates inflammation and reduces atherosclerosis in apolipoprotein E deficient mice. J Transl Med 2015; 13:316. [PMID: 26410585 PMCID: PMC4584131 DOI: 10.1186/s12967-015-0677-8] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2015] [Accepted: 09/18/2015] [Indexed: 12/19/2022] Open
Abstract
BACKGROUND Methionine sulfoxide reductase A (MsrA) is a potent intracellular oxidoreductase and serves as an essential factor that protects cells against oxidative damage. However, therapeutic use of exogenous MsrA in oxidative stress-induced diseases is limited, because it cannot enter the cells. The aim of this study is to investigate whether MsrA with PEP-1, a cell penetrating peptide, fused to its N-terminus can protect against oxidative stress in macrophages and can attenuate atherosclerosis in apolipoprotein E deficient (apoE(-/-)) mice. METHODS MsrA and the fusion protein PEP-1-MsrA were expressed and purified using a pET28a expression system. Transduction of the fusion protein into macrophages was confirmed by Western blot and immunofluorescence staining. Intracellular reactive oxygen species (ROS) and apoptosis levels were measured by flow cytometry. In in vivo study, MsrA or PEP-1-MsrA proteins were intraperitoneally injected into apoE(-/-) mice fed a Western diet for 12 weeks. Plasma lipids levels, inflammatory gene expression, and paraoxonase-1 (PON1) and superoxide dismutase (SOD) activities were assessed. Atherosclerotic lesions were analyzed by Oil Red O staining and immunohistochemistry. RESULTS PEP-1-MsrA could penetrate the cells and significantly reduced intracellular ROS levels and apoptosis in H2O2-treated macrophages. It also decreased TNFα and IL-1β mRNA levels and increased the IL-10 mRNA level in lipopolysaccharide-treated macrophages. In in vivo study, PEP-1-MsrA injection significantly increased plasma PON1 and SOD activities and decreased plasma monocyte chemoattractant protein 1 (MCP-1) level compared to the injection of vehicle control or MsrA. In PEP-1-MsrA injected mice, hepatic PON1 levels were increased, while the expression of TNFα and IL-6 mRNA in the liver was suppressed. Although plasma total cholesterol and triglyceride levels did not change, the aortic atherosclerosis in PEP-1-MsrA treated mice was significantly reduced. This was accompanied by a reduction of total and apoptotic macrophages in the lesions. CONCLUSION Our study provides evidence that PEP-1-MsrA may be a potential therapeutic agent for atherosclerosis-related cardiovascular diseases.
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Affiliation(s)
- Yao Wu
- Department of Biochemistry and Molecular Biology, Hubei Provincial Key Laboratory of Developmentally Originated Disease, Wuhan University School of Basic Medical Sciences, 185 Donghu Road, Bldg. 2, 2-209, Wuhan, 430071, Hubei, China.
| | - Guanghui Xie
- Department of Biochemistry and Molecular Biology, Hubei Provincial Key Laboratory of Developmentally Originated Disease, Wuhan University School of Basic Medical Sciences, 185 Donghu Road, Bldg. 2, 2-209, Wuhan, 430071, Hubei, China.
| | - Yanyong Xu
- Department of Biochemistry and Molecular Biology, Hubei Provincial Key Laboratory of Developmentally Originated Disease, Wuhan University School of Basic Medical Sciences, 185 Donghu Road, Bldg. 2, 2-209, Wuhan, 430071, Hubei, China.
| | - Li Ma
- Department of Biochemistry and Molecular Biology, Hubei Provincial Key Laboratory of Developmentally Originated Disease, Wuhan University School of Basic Medical Sciences, 185 Donghu Road, Bldg. 2, 2-209, Wuhan, 430071, Hubei, China.
| | - Chuanfeng Tong
- Cardiology Division of Wuhan University Zhongnan Hospital, Wuhan, China.
| | - Daping Fan
- Department of Cell Biology and Anatomy, School of Medicine, University of South Carolina, Columbia, SC, USA.
| | - Fen Du
- Department of Biochemistry and Molecular Biology, Hubei Provincial Key Laboratory of Developmentally Originated Disease, Wuhan University School of Basic Medical Sciences, 185 Donghu Road, Bldg. 2, 2-209, Wuhan, 430071, Hubei, China.
| | - Hong Yu
- Department of Biochemistry and Molecular Biology, Hubei Provincial Key Laboratory of Developmentally Originated Disease, Wuhan University School of Basic Medical Sciences, 185 Donghu Road, Bldg. 2, 2-209, Wuhan, 430071, Hubei, China.
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Friedemann M, Helk E, Tiiman A, Zovo K, Palumaa P, Tõugu V. Effect of methionine-35 oxidation on the aggregation of amyloid-β peptide. Biochem Biophys Rep 2015; 3:94-99. [PMID: 29124171 PMCID: PMC5668694 DOI: 10.1016/j.bbrep.2015.07.017] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2015] [Revised: 07/22/2015] [Accepted: 07/28/2015] [Indexed: 01/12/2023] Open
Abstract
Aggregation of Aβ peptides into amyloid plaques is considered to trigger the Alzheimer’s disease (AD), however the mechanism behind the AD onset has remained elusive. It is assumed that the insoluble Aβ aggregates enhance oxidative stress (OS) by generating free radicals with the assistance of bound copper ions. The aim of our study was to establish the role of Met35 residue in the oxidation and peptide aggregation processes. Met35 can be readily oxidized by H2O2. The fibrillization of Aβ with Met35 oxidized to sulfoxide was three times slower compared to that of the regular peptide. The fibrils of regular and oxidized peptides looked similar under transmission electron microscopy. The relatively small inhibitory effect of methionine oxidation on the fibrillization suggests that the possible variation in the Met oxidation state should not affect the in vivo plaque formation. The peptide oxidation pattern was more complex when copper ions were present: addition of one oxygen atom was still the fastest process, however, it was accompanied by multiple unspecific modifications of peptide residues. Addition of copper ions to the Aβ with oxidized Met35 in the presence of H2O2, resulted a similar pattern of nonspecific modifications, suggesting that the one-electron oxidation processes in the peptide molecule do not depend on the oxidation state of Met35 residue. Thus, it can be concluded that Met35 residue is not a part of the radical generating mechanism of Aβ–Cu(II) complex. Aβ peptides with oxidized Met35 residue fibrillize three times slower than the reduced peptide. Met35 is the only residue in Aβ peptide that is oxidized by H2O2 in the absent of copper ions. In the presence of copper ions as catalyst multiple unspecific oxidative processes occur in Aβ. Previous oxidation of Met35 does not affect the unspecific oxidation in the presence of copper ions.
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Key Words
- AD, Alzheimer's disease
- Alzheimer's disease
- Aβ, Alzheimer's amyloid peptide
- Copper(II)ion
- HFIP, 1,1,1,3,3,3-hexafluoro-2-propanol
- Methionine oxidation
- OS, oxidative stress
- ROS, reactive oxygen species
- ThT, Thioflavin T
- β-amyloid
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Affiliation(s)
- Merlin Friedemann
- Department of Gene Technology, Tallinn University of Technology, Akadeemia tee 15, 12618 Tallinn, Estonia
| | - Eneken Helk
- Department of Gene Technology, Tallinn University of Technology, Akadeemia tee 15, 12618 Tallinn, Estonia
| | - Ann Tiiman
- Department of Gene Technology, Tallinn University of Technology, Akadeemia tee 15, 12618 Tallinn, Estonia
| | - Kairit Zovo
- Department of Gene Technology, Tallinn University of Technology, Akadeemia tee 15, 12618 Tallinn, Estonia
| | - Peep Palumaa
- Department of Gene Technology, Tallinn University of Technology, Akadeemia tee 15, 12618 Tallinn, Estonia
| | - Vello Tõugu
- Department of Gene Technology, Tallinn University of Technology, Akadeemia tee 15, 12618 Tallinn, Estonia
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Carelli-Alinovi C, Giardina B, Misiti F. Amyloid beta peptide (1-42)-mediated antioxidant imbalance is associated with activation of protein kinase C in red blood cells. Cell Biochem Funct 2015; 33:196-201. [PMID: 25914333 DOI: 10.1002/cbf.3103] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2015] [Revised: 03/18/2015] [Accepted: 03/18/2015] [Indexed: 01/09/2023]
Abstract
Glycolysis and pentose phosphate pathway (PPP) in red blood cell (RBC) are modulated by the cell oxygenation state. This metabolic modulation is connected to variations in intracellular nicotinamide adenine dinucleotide phosphate-reduced form (NADPH) and adenosine triphosphate (ATP) levels as a function of the oxygenation state of the cell, and, consequently, it should have physiologic relevance. In the present study, we analysed the effects of amyloid beta peptide (1-42) (Abeta) on RBC metabolism and its relationship with the activity of protein kinase C (PKC). Our results showed that metabolic response to Abeta depended on the degree of cell oxygenation. In particular, under high O2 pressure, in Abeta-treated RBC, glucose metabolized through PPP approached that metabolized by RBC under low O2 pressure, differently to that observed in untreated cells. The effect of Abeta on RBC metabolism was paralleled by increase in PKC enzyme activity, but cytosolic Ca2+ concentration does not seem to be involved in this mechanism. Incubation of Abeta-treated RBC with a specific inhibitor of PKC partially restores PPP flux. A possible rationalization of the different metabolic behaviours shown by RBC following Abeta treatment is proposed. It takes into account the known post-translational modifications to cytoskeleton proteins induced by PKC. The reduction in PPP flux may lead to a weakened defence system of antioxidant reserve in RBC, becoming a source of reactive species, and, consequently, its typical, structural and functional features are lost. Therefore, oxidative stress may outflow from the RBC and trigger damage events in adjacent cells and tissue, thus contributing to vascular damage.
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Affiliation(s)
- Cristiana Carelli-Alinovi
- Biochemistry and Clinical Biochemistry Institute, School of Medicine, Catholic University, Rome, Italy
| | - Bruno Giardina
- Biochemistry and Clinical Biochemistry Institute, School of Medicine, Catholic University, Rome, Italy.,Istituto di Chimica del Riconoscimento Molecolare (ICRM), National Research Council (CNR), Rome, Italy
| | - Francesco Misiti
- Department of Human Sciences, Society and Health, University of Cassino and Southern Lazio, Cassino, FR, Italy
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Minniti AN, Arrazola MS, Bravo-Zehnder M, Ramos F, Inestrosa NC, Aldunate R. The protein oxidation repair enzyme methionine sulfoxide reductase a modulates Aβ aggregation and toxicity in vivo. Antioxid Redox Signal 2015; 22:48-62. [PMID: 24988428 PMCID: PMC4270145 DOI: 10.1089/ars.2013.5803] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
AIMS To examine the role of the enzyme methionine sulfoxide reductase A-1 (MSRA-1) in amyloid-β peptide (Aβ)-peptide aggregation and toxicity in vivo, using a Caenorhabditis elegans model of the human amyloidogenic disease inclusion body myositis. RESULTS MSRA-1 specifically reduces oxidized methionines in proteins. Therefore, a deletion of the msra-1 gene was introduced into transgenic C. elegans worms that express the Aβ-peptide in muscle cells to prevent the reduction of oxidized methionines in proteins. In a constitutive transgenic Aβ strain that lacks MSRA-1, the number of amyloid aggregates decreases while the number of oligomeric Aβ species increases. These results correlate with enhanced synaptic dysfunction and mislocalization of the nicotinic acetylcholine receptor ACR-16 at the neuromuscular junction (NMJ). INNOVATION This approach aims at modulating the oxidation of Aβ in vivo indirectly by dismantling the methionine sulfoxide repair system. The evidence presented here shows that the absence of MSRA-1 influences Aβ aggregation and aggravates locomotor behavior and NMJ dysfunction. The results suggest that therapies which boost the activity of the Msr system could have a beneficial effect in managing amyloidogenic pathologies. CONCLUSION The absence of MSRA-1 modulates Aβ-peptide aggregation and increments its deleterious effects in vivo.
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Affiliation(s)
- Alicia N Minniti
- 1 Facultad de Ciencias Biológicas, Pontificia Universidad Católica de Chile , Santiago, Chile
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Butterfield DA, Swomley AM, Sultana R. Amyloid β-peptide (1-42)-induced oxidative stress in Alzheimer disease: importance in disease pathogenesis and progression. Antioxid Redox Signal 2013; 19:823-35. [PMID: 23249141 PMCID: PMC3749710 DOI: 10.1089/ars.2012.5027] [Citation(s) in RCA: 365] [Impact Index Per Article: 33.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/22/2012] [Revised: 12/05/2012] [Accepted: 12/17/2012] [Indexed: 12/14/2022]
Abstract
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.
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Affiliation(s)
- D Allan Butterfield
- Department of Chemistry, University of Kentucky, Lexington, Kentucky 40506-0055, USA.
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25
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Bibl M, Gallus M, Welge V, Lehmann S, Sparbier K, Esselmann H, Wiltfang J. Characterization of cerebrospinal fluid aminoterminally truncated and oxidized amyloid-β peptides. Proteomics Clin Appl 2012; 6:163-9. [PMID: 22532452 DOI: 10.1002/prca.201100082] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
PURPOSE Carboxyterminally elongated and aminoterminally truncated Aβ peptides as well as their pyroglutamate and oxidized derivates are major constituents of human amyloid plaques. The objective of the present study was to characterize aminoterminally truncated or oxidized Aβ38, Aβ40, and Aβ42 peptide species in immunoprecipitated human cerebrospinal fluid (CSF). EXPERIMENTAL DESIGN We invented a novel sequential aminoterminally and carboxyterminally specific immunoprecipitation protocol and used the Aβ-SDS-PAGE/immunoblot for subsequent analysis of CSF Aβ peptide patterns. RESULTS In the present study, we identified the aminoterminally truncated Aβ peptides 2-40 and 2-42 as well as oxidized forms of Aβ1-38 and Aβ1-42 in CSF. Our protocol allowed the quantification of a pattern of Aβ peptides 1-38(ox), 2-40, and 2-42 in addition to the well known panel of Aβ 1-37, 1-38, 1-39, 1-40, 1-40(ox), and 1-42 in a group of seven patients with peripheral polyneuropathy. CONCLUSIONS AND CLINICAL RELEVANCE In the present approach, we could broaden the range of quantifiable Aβ peptides described in previous studies (i.e., 1-37, 1-38, 1-39, 1-40, 1-40(ox), and 1-42) by Aβ 1-38(ox), 2-40, and 2-42. An exact analysis of CSF Aβ peptides regarding their carboxy- and aminoterminus as well as posttranslational modification seems promising with respect to diagnostic and pathogenic aspects.
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Affiliation(s)
- Mirko Bibl
- Department of Psychiatry, Psychotherapy and Addiction Medicine, Kliniken Essen-Mitte, University of Duisburg-Essen, Essen, Germany.
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Cui ZJ, Han ZQ, Li ZY. Modulating protein activity and cellular function by methionine residue oxidation. Amino Acids 2012; 43:505-17. [PMID: 22146868 DOI: 10.1007/s00726-011-1175-9] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2011] [Accepted: 11/21/2011] [Indexed: 02/07/2023]
Abstract
The sulfur-containing amino acid residue methionine (Met) in a peptide/protein is readily oxidized to methionine sulfoxide [Met(O)] by reactive oxygen species both in vitro and in vivo. Methionine residue oxidation by oxidants is found in an accumulating number of important proteins. Met sulfoxidation activates calcium/calmodulin-dependent protein kinase II and the large conductance calcium-activated potassium channels, delays inactivation of the Shaker potassium channel ShC/B and L-type voltage-dependent calcium channels. Sulfoxidation at critical Met residues inhibits fibrillation of atherosclerosis-related apolipoproteins and multiple neurodegenerative disease-related proteins, such as amyloid beta, α-synuclein, prion, and others. Methionine residue oxidation is also correlated with marked changes in cellular activities. Controlled key methionine residue oxidation may be used as an oxi-genetics tool to dissect specific protein function in situ.
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Affiliation(s)
- Zong Jie Cui
- Institute of Cell Biology, Beijing Normal University, Beijing 100875, China.
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27
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Zhang X, Wang J, Xing Y, Gong L, Li H, Wu Z, Li Y, Wang J, Wang Y, Dong L, Li S. Effects of ginsenoside Rg1 or 17β-estradiol on a cognitively impaired, ovariectomized rat model of Alzheimer's disease. Neuroscience 2012; 220:191-200. [PMID: 22728092 DOI: 10.1016/j.neuroscience.2012.06.027] [Citation(s) in RCA: 60] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2012] [Revised: 06/08/2012] [Accepted: 06/11/2012] [Indexed: 01/08/2023]
Abstract
Ginsenoside Rg1, which could improve spatial learning and memory, might be a useful agent for preventing and treating cognitive impairment in Alzheimer's disease (AD). The present study was designed to test the neuroprotective effects of ginsenoside Rg1 on an ovariectomized (OVX) and d-galactose (d-gal)-injected rat model of AD, which is characterized with progressive learning and memory deficits, AD-related molecules alteration and differentiation/apoptosis imbalance in hippocampal neurons. OVX Wistar rats received daily injections of d-gal (100mg/kg) combined with different concentrations of ginsenoside Rg1 (5, 10, 20mg/kg) or 17-β-estradiol (E2, 100 μg/kg), or normal saline (NS, 1.0 ml/kg) for 6 weeks. Ovarian steroid deprivation plus d-gal injection led to spatial learning and memory capacity impairments, as well as increased Aβ(1-42) production. Ginsenoside Rg1 and E2-treatment significantly ameliorated these deteriorations in AD rats. Seven weeks after surgery, α-secretase a disintegrin and metallopeptidase domain 10 (ADAM 10) in hippocampus of AD rats was dramatically decreased, while β-secretase β-site APP-cleaving enzyme 1 (BACE 1) increased compared with those in sham-operated ones (P<0.05). Levels of cleaved caspase 3 were increased in the hippocampus of AD rats. Ginsenoside Rg1 and E2-treatment increased ADAM 10 level while reduced BACE 1 level and apoptosis. Moreover, moderate i.e. 10mg/kg/d and high i.e. 20mg/kg/d ginsenoside Rg1 displayed more effective function than low i.e. 5mg/kg/d ginsenoside Rg1. Our findings demonstrate the neuroprotective effects of ginsenoside Rg1 and E2 on AD rats and support the potential application of ginsenoside Rg1 in the treatment of learning and memory impairments in postmenopausal women.
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Affiliation(s)
- X Zhang
- Department of Traditional Chinese Integrated Western Medicine, Qi Lu Hospital, Shandong University, Jinan 250012, PR China
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Sato K, Maeda T, Hoshi M. Asn27 is Essential for the Neurotoxicity of Amyloid β(1–42) Peptide. Int J Pept Res Ther 2012. [DOI: 10.1007/s10989-012-9310-3] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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Bi BT, Lin HB, Cheng YF, Zhou H, Lin T, Zhang MZ, Li TJ, Xu JP. Promotion of β-amyloid production by C-reactive protein and its implications in the early pathogenesis of Alzheimer's disease. Neurochem Int 2011; 60:257-66. [PMID: 22202667 DOI: 10.1016/j.neuint.2011.12.007] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2011] [Revised: 12/06/2011] [Accepted: 12/12/2011] [Indexed: 10/14/2022]
Abstract
C-reactive protein (CRP) and β-amyloid protein (Aβ) are involved in the development of Alzheimer's disease (AD). However, the relationship between CRP and Aβ production is unclear. In vitro and in vivo experiments were performed to investigate the association of CRP with Aβ production. Using the rat adrenal pheochromocytoma cell line (PC12 cells) to mimic neurons, cytotoxicity was evaluated by cell viability and supernatant lactate dehydrogenase (LDH) activity. The levels of amyloid precursor protein (APP), beta-site APP cleaving enzyme (BACE-1), and presenilins (PS-1 and PS-2) were investigated using real-time polymerase chain reaction and Western blotting analysis. Aβ1-42 was measured by enzyme-linked immunosorbent assay. The relevance of CRP and Aβ as well as potential mechanisms were studied using APP/PS1 transgenic (Tg) mice. Treatment with 0.5-4.0 μM CRP for 48 h decreased cell viability and increased LDH leakage in PC12 cells. Incubation with CRP at a sub-toxic concentration of 0.2 μM increased the mRNA levels of APP, BACE-1, PS-1, and PS-2, as well as Aβ1-42 production. CRP inhibitor reversed the CRP-induced upregulations of the mRNA levels of APP, BACE-1, PS-1, and PS-2, and the protein levels of APP, BACE-1, PS-1, and Aβ1-42, but did not reversed Aβ1-42 cytotoxicity. The cerebral levels of CRP and Aβ1-42 in APP/PS1 Tg mice were positively correlated, accompanied with the elevated mRNA expressions of serum amyloid P component (SAP), complement component 1q (C1q), and tumor necrosis factor-α (TNF-α). These results suggest that CRP cytotoxicity is associated with Aβ formation and Aβ-related markers expressions; CRP and Aβ were relevant in early-stage AD; CRP may be an important trigger in AD pathogenesis.
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Affiliation(s)
- Bing-Tian Bi
- Department of Pharmacology, School of Pharmaceutical Sciences, Southern Medical University, Guangzhou, Guangdong 510515, China
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Moskovitz J, Maiti P, Lopes DHJ, Oien DB, Attar A, Liu T, Mittal S, Hayes J, Bitan G. Induction of methionine-sulfoxide reductases protects neurons from amyloid β-protein insults in vitro and in vivo. Biochemistry 2011; 50:10687-97. [PMID: 22059533 PMCID: PMC3235361 DOI: 10.1021/bi201426b] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
Self-assembly of amyloid β-protein (Aβ) into toxic oligomers and fibrillar polymers is believed to cause Alzheimer's disease (AD). In the AD brain, a high percentage of Aβ contains Met-sulfoxide at position 35, though the role this modification plays in AD is not clear. Oxidation of Met(35) to sulfoxide has been reported to decrease the extent of Aβ assembly and neurotoxicity, whereas surprisingly, oxidation of Met(35) to sulfone yields a toxicity similar to that of unoxidized Aβ. We hypothesized that the lower toxicity of Aβ-sulfoxide might result not only from structural alteration of the C-terminal region but also from activation of methionine-sulfoxide reductase (Msr), an important component of the cellular antioxidant system. Supporting this hypothesis, we found that the low toxicity of Aβ-sulfoxide correlated with induction of Msr activity. In agreement with these observations, in MsrA(-/-) mice the difference in toxicity between native Aβ and Aβ-sulfoxide was essentially eliminated. Subsequently, we found that treatment with N-acetyl-Met-sulfoxide could induce Msr activity and protect neuronal cells from Aβ toxicity. In addition, we measured Msr activity in a double-transgenic mouse model of AD and found that it was increased significantly relative to that of nontransgenic mice. Immunization with a novel Met-sulfoxide-rich antigen for 6 months led to antibody production, decreased Msr activity, and lowered hippocampal plaque burden. The data suggest an important neuroprotective role for the Msr system in the AD brain, which may lead to development of new therapeutic approaches for AD.
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Affiliation(s)
- Jackob Moskovitz
- Department of Pharmacology and Toxicology, School of Pharmacy, University of Kansas, 1251 Wescoe Hall Dr., Lawrence, KS 66045, USA
| | - Panchanan Maiti
- Department of Neurology, David Geffen School of Medicine, University of California at Los Angeles, 635 Charles E. Young Drive South, Los Angeles, CA 90095, USA
| | - Dahabada H. J. Lopes
- Department of Neurology, David Geffen School of Medicine, University of California at Los Angeles, 635 Charles E. Young Drive South, Los Angeles, CA 90095, USA
| | - Derek B. Oien
- Department of Pharmacology and Toxicology, School of Pharmacy, University of Kansas, 1251 Wescoe Hall Dr., Lawrence, KS 66045, USA
| | - Aida Attar
- Department of Neurology, David Geffen School of Medicine, University of California at Los Angeles, 635 Charles E. Young Drive South, Los Angeles, CA 90095, USA
- Brain Research Institute, University of California at Los Angeles, 635 Charles E. Young Drive South, Los Angeles, CA 90095, USA
| | - Tingyu Liu
- Department of Neurology, David Geffen School of Medicine, University of California at Los Angeles, 635 Charles E. Young Drive South, Los Angeles, CA 90095, USA
| | - Shivina Mittal
- Department of Neurology, David Geffen School of Medicine, University of California at Los Angeles, 635 Charles E. Young Drive South, Los Angeles, CA 90095, USA
| | - Jane Hayes
- Department of Neurology, David Geffen School of Medicine, University of California at Los Angeles, 635 Charles E. Young Drive South, Los Angeles, CA 90095, USA
| | - Gal Bitan
- Department of Neurology, David Geffen School of Medicine, University of California at Los Angeles, 635 Charles E. Young Drive South, Los Angeles, CA 90095, USA
- Brain Research Institute, University of California at Los Angeles, 635 Charles E. Young Drive South, Los Angeles, CA 90095, USA
- Molecular Biology Institute, University of California at Los Angeles, 635 Charles E. Young Drive South, Los Angeles, CA 90095, USA
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Butterfield DA, Sultana R. Methionine-35 of aβ(1-42): importance for oxidative stress in Alzheimer disease. JOURNAL OF AMINO ACIDS 2011; 2011:198430. [PMID: 22312456 PMCID: PMC3268025 DOI: 10.4061/2011/198430] [Citation(s) in RCA: 63] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/01/2011] [Accepted: 04/14/2011] [Indexed: 01/09/2023]
Abstract
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.
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Affiliation(s)
- D. Allan Butterfield
- Department of Chemistry, University of Kentucky, Lexington, KY 40506-0055, USA
- Center of Membrane Sciences, University of Kentucky, Lexington, KY 40506-0055, USA
- Sanders-Brown Center on Aging, University of Kentucky, Lexington, KY 40506-0055, USA
| | - Rukhsana Sultana
- Department of Chemistry, University of Kentucky, Lexington, KY 40506-0055, USA
- Center of Membrane Sciences, University of Kentucky, Lexington, KY 40506-0055, USA
- Sanders-Brown Center on Aging, University of Kentucky, Lexington, KY 40506-0055, USA
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Surprising toxicity and assembly behaviour of amyloid β-protein oxidized to sulfone. Biochem J 2011; 433:323-32. [PMID: 21044048 DOI: 10.1042/bj20101391] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
Aβ (amyloid β-peptide) is believed to cause AD (Alzheimer's disease). Aβ42 (Aβ comprising 42 amino acids) is substantially more neurotoxic than Aβ40 (Aβ comprising 40 amino acids), and this increased toxicity correlates with the existence of unique Aβ42 oligomers. Met³⁵ oxidation to sulfoxide or sulfone eliminates the differences in early oligomerization between Aβ40 and Aβ42. Met³⁵ oxidation to sulfoxide has been reported to decrease Aβ assembly kinetics and neurotoxicity, whereas oxidation to sulfone has rarely been studied. Based on these data, we expected that oxidation of Aβ to sulfone would also decrease its toxicity and assembly kinetics. To test this hypothesis, we compared systematically the effect of the wild-type, sulfoxide and sulfone forms of Aβ40 and Aβ42 on neuronal viability, dendritic spine morphology and macroscopic Ca²(+) currents in primary neurons, and correlated the data with assembly kinetics. Surprisingly, we found that, in contrast with Aβ-sulfoxide, Aβ-sulfone was as toxic and aggregated as fast, as wild-type Aβ. Thus, although Aβ-sulfone is similar to Aβ-sulfoxide in its dipole moment and oligomer size distribution, it behaves similarly to wild-type Aβ in its aggregation kinetics and neurotoxicity. These surprising data decouple the toxicity of oxidized Aβ from its initial oligomerization, and suggest that our current understanding of the effect of methionine oxidation in Aβ is limited.
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Ma B, Nussinov R. Polymorphic C-terminal beta-sheet interactions determine the formation of fibril or amyloid beta-derived diffusible ligand-like globulomer for the Alzheimer Abeta42 dodecamer. J Biol Chem 2010; 285:37102-10. [PMID: 20847046 PMCID: PMC2978638 DOI: 10.1074/jbc.m110.133488] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2010] [Revised: 08/27/2010] [Indexed: 12/31/2022] Open
Abstract
The relationship between amyloid deposition and cellular toxicity is still controversial. In addition to fibril-forming oligomers, other soluble Aβ forms (amyloid β-derived diffusible ligands (ADDLs)) were also suggested to form and to present different morphologies and mechanisms of toxicity. One ADDL type, the "globulomer," apparently forms independently of the fibril aggregation pathway. Even though many studies argue that such soluble Aβ oligomers are off fibril formation pathways, they may nonetheless share some structural similarity with protofibrils. NMR data of globulomer intermediates, "preglobulomers," suggested parallel in-register C-terminal β-sheets, with different N-terminal conformations. Based on experimental data, we computationally investigate four classes of Aβ dodecamers: fibril, fibril oligomer, prefibril/preglobulomer cluster, and globulomer models. Our simulations of the solvent protection of double-layered fibril and globulomer models reproduce experimental observations. Using a single layer Aβ fibril oligomer β-sheet model, we found that the C-terminal β-sheet in the fibril oligomer is mostly curved, preventing it from quickly forming a fibril and leading to its breaking into shorter pieces. The simulations also indicate that β-sheets packed orthogonally could be the most stable species for Aβ dodecamers. The major difference between fibril-forming oligomers and ADDL-like oligomers (globulomers) could be the exposure of Met-35 patches. Although the Met-35 patches are necessarily exposed in fibril-forming oligomers to allow their maturation into fibrils, the Met-35 patches in the globulomer are covered by other residues in the orthogonally packed Aβ peptides. Our results call attention to the possible existence of certain "critical intermediates" that can lead to both seeds and other soluble ADDL-like oligomers.
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Affiliation(s)
- Buyong Ma
- Basic Science Program, SAIC-Frederick, Inc., Center for Cancer Research Nanobiology Program, National Cancer Institute, Frederick, Maryland 21702, USA.
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