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Lippi A, Krisko A. Protein aggregation: A detrimental symptom or an adaptation mechanism? J Neurochem 2024; 168:1426-1441. [PMID: 37694504 DOI: 10.1111/jnc.15955] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2023] [Revised: 08/21/2023] [Accepted: 08/22/2023] [Indexed: 09/12/2023]
Abstract
Protein quality control mechanisms oversee numerous aspects of protein lifetime. From the point of protein synthesis, protein homeostasis machineries take part in folding, solubilization, and/or degradation of impaired proteins. Some proteins follow an alternative path upon loss of their solubility, thus are secluded from the cytosol and form protein aggregates. Protein aggregates differ in their function and composition, rendering protein aggregation a complex phenomenon that continues to receive plenty of attention in the scientific and medical communities. Traditionally, protein aggregates have been associated with aging and a large spectrum of protein folding diseases, such as neurodegenerative diseases, type 2 diabetes, or cataract. However, a body of evidence suggests that they may act as an adaptive mechanism to overcome transient stressful conditions, serving as a sink for the removal of misfolded proteins from the cytosol or storage compartments for machineries required upon stress release. In this review, we present examples and evidence elaborating different possible roles of protein aggregation and discuss their potential roles in stress survival, aging, and disease, as well as possible anti-aggregation interventions.
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Affiliation(s)
- Alice Lippi
- Department of Experimental Neurodegeneration, University Medical Center Göttingen, Göttingen, Germany
| | - Anita Krisko
- Department of Experimental Neurodegeneration, University Medical Center Göttingen, Göttingen, Germany
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2
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Li L, Wei Z, Tang Y, Jin M, Yao H, Li X, Li Q, Tan J, Xiao B. Icaritin greatly attenuates β-amyloid-induced toxicity in vivo. CNS Neurosci Ther 2024; 30:e14527. [PMID: 37990437 PMCID: PMC11017459 DOI: 10.1111/cns.14527] [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: 07/24/2023] [Revised: 10/30/2023] [Accepted: 11/02/2023] [Indexed: 11/23/2023] Open
Abstract
AIMS The accumulation and deposition of β-amyloid (Aβ) has always been considered a major pathological feature of Alzheimer's disease (AD). The latest and mainstream amyloid cascade hypothesis indicates that all the main pathological changes in AD are attributed to the accumulation of soluble Aβ. However, the exploration of therapeutic drugs for Aβ toxicity has progressed slowly. This study aims to investigate the protective effects of Icaritin on the Aβ-induced Drosophila AD model and its possible mechanism. METHODS To identify the effects of Icaritin on AD, we constructed an excellent Drosophila AD model named Aβarc (arctic mutant Aβ42) Drosophila. Climbing ability, flight ability, and longevity were used to evaluate the effects of Icaritin on AD phenotypes. Aβarc was determined by immunostaining and ELISA. To identify the effects of Icaritin on oxidative stress, we performed the detection of ROS, hydrogen peroxide, MDA, SOD, catalase, GST, and Caspase-3. To identify the effects of Icaritin on energy metabolism, we performed the detection of ATP and lactate. Transcriptome analysis and qRT-PCR verifications were used to detect the genes directly involved in oxidative stress and energy metabolism. Mitochondrial structure and function were detected by an electron microscopy assay, a mitochondrial membrane potential assay, and a mitochondrial respiration assay. RESULTS We discovered that Icaritin almost completely rescues the climbing ability, flight ability, and longevity of Aβarc Drosophila. Aβarc was dramatically reduced by Icaritin treatment. We also found that Icaritin significantly reduces oxidative stress and greatly improves impaired energy metabolism. Importantly, transcriptome analysis and qRT-PCR verifications showed that many key genes, directly involved in oxidative stress and energy metabolism, are restored by Icaritin. Next, we found that Icaritin perfectly restores the integrity of mitochondrial structure and function damaged by Aβarc toxicity. CONCLUSION This study suggested that Icaritin is a potential drug to deal with the toxicity of Aβarc, at least partially realized by restoring the mitochondria/oxidative stress/energy metabolism axis, and holds potential for translation to human AD.
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Affiliation(s)
- Liangxian Li
- Laboratory of Respiratory DiseaseAffiliated Hospital of Guilin Medical UniversityGuilinChina
- Guangxi Key Laboratory of Brain and Cognitive NeuroscienceGuilin Medical UniversityGuilinChina
| | - Zaiwa Wei
- Guangxi Key Laboratory of Brain and Cognitive NeuroscienceGuilin Medical UniversityGuilinChina
| | - Yafang Tang
- Clinical Research Center for Neurological Diseases of Guangxi ProvinceAffiliated Hospital of Guilin Medical UniversityGuilinChina
| | - Mingyue Jin
- Guangxi Key Laboratory of Brain and Cognitive NeuroscienceGuilin Medical UniversityGuilinChina
| | - Hua Yao
- Guangxi Key Laboratory of Brain and Cognitive NeuroscienceGuilin Medical UniversityGuilinChina
| | - Xia Li
- Guangxi Key Laboratory of Brain and Cognitive NeuroscienceGuilin Medical UniversityGuilinChina
| | - Qinghua Li
- Guangxi Key Laboratory of Brain and Cognitive NeuroscienceGuilin Medical UniversityGuilinChina
- Clinical Research Center for Neurological Diseases of Guangxi ProvinceAffiliated Hospital of Guilin Medical UniversityGuilinChina
- Guangxi Engineering Research Center for Digital Medicine and Clinical TranslationAffiliated Hospital of Guilin Medical UniversityGuilinChina
| | - Jie Tan
- Guangxi Key Laboratory of Brain and Cognitive NeuroscienceGuilin Medical UniversityGuilinChina
| | - Bo Xiao
- Laboratory of Respiratory DiseaseAffiliated Hospital of Guilin Medical UniversityGuilinChina
- Guangxi Key Laboratory of Brain and Cognitive NeuroscienceGuilin Medical UniversityGuilinChina
- The Key Laboratory of Respiratory DiseasesEducation Department of Guangxi Zhuang Autonomous RegionGuilinChina
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3
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Elovsson G, Klingstedt T, Brown M, Nilsson KPR, Brorsson AC. A Novel Drosophila Model of Alzheimer's Disease to Study Aβ Proteotoxicity in the Digestive Tract. Int J Mol Sci 2024; 25:2105. [PMID: 38396782 PMCID: PMC10888607 DOI: 10.3390/ijms25042105] [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: 12/05/2023] [Revised: 02/02/2024] [Accepted: 02/06/2024] [Indexed: 02/25/2024] Open
Abstract
Amyloid-β (Aβ) proteotoxicity is associated with Alzheimer's disease (AD) and is caused by protein aggregation, resulting in neuronal damage in the brain. In the search for novel treatments, Drosophila melanogaster has been extensively used to screen for anti-Aβ proteotoxic agents in studies where toxic Aβ peptides are expressed in the fly brain. Since drug molecules often are administered orally there is a risk that they fail to reach the brain, due to their inability to cross the brain barrier. To circumvent this problem, we have designed a novel Drosophila model that expresses the Aβ peptides in the digestive tract. In addition, a built-in apoptotic sensor provides a fluorescent signal from the green fluorescent protein as a response to caspase activity. We found that expressing different variants of Aβ1-42 resulted in proteotoxic phenotypes such as reduced longevity, aggregate deposition, and the presence of apoptotic cells. Taken together, this gut-based Aβ-expressing fly model can be used to study the mechanisms behind Aβ proteotoxicity and to identify different substances that can modify Aβ proteotoxicity.
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Affiliation(s)
| | | | | | | | - Ann-Christin Brorsson
- Department of Physics, Chemistry, and Biology, Linköping University, 581 83 Linköping, Sweden; (G.E.); (T.K.); (M.B.); (K.P.R.N.)
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Zhang L, Zhu B, Zhou X, Ning H, Zhang F, Yan B, Chen J, Ma T. ZNF787 and HDAC1 Mediate Blood-Brain Barrier Permeability in an In Vitro Model of Alzheimer's Disease Microenvironment. Neurotox Res 2024; 42:12. [PMID: 38329647 DOI: 10.1007/s12640-024-00693-4] [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: 05/31/2023] [Revised: 12/19/2023] [Accepted: 01/30/2024] [Indexed: 02/09/2024]
Abstract
The permeability of the blood-brain barrier (BBB) is increased in Alzheimer's disease (AD). This plays a key role in the instigation and maintenance of chronic inflammation during AD. Experiments using AD models showed that the increased permeability of the BBB was mainly caused by the decreased expression of tight junction-related proteins occludin and claudin-5. In this study, we found that ZNF787 and HDAC1 were upregulated in β-amyloid (Aβ)1-42-incubated endothelial cells, resulting in increased BBB permeability. Conversely, the silencing of ZNF787 and HDAC1 by RNAi led to reduced BBB permeability. The silencing of ZNF787 and HDAC1 enhanced the expression of occludin and claudin-5. Mechanistically, ZNF787 binds to promoter regions for occludin and claudin-5 and functions as a transcriptional regulator. Furthermore, we demonstrate that ZNF787 interacts with HDAC1, and this resulted in the downregulation of the expression of genes encoding tight junction-related proteins to increase in BBB permeability. Taken together, our study identifies critical roles for the interaction between ZNF787 and HDAC1 in regulating BBB permeability and the pathogenesis of AD.
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Affiliation(s)
- Lu Zhang
- Department of Neurobiology, School of Life Sciences, China Medical University, Shenyang, 110122, China
| | - Baicheng Zhu
- Department of Neurobiology, School of Life Sciences, China Medical University, Shenyang, 110122, China
| | - Xinxin Zhou
- Liaoning University of Traditional Chinese Medicine, Shenyang, 110034, China
| | - Hao Ning
- Department of Neurobiology, School of Life Sciences, China Medical University, Shenyang, 110122, China
| | - Fengying Zhang
- Department of Neurology, Affiliated Nanhua Hospital, University of South China, Hengyang, 421001, China
| | - Bingju Yan
- Department of Cardiology, the First Affiliated Hospital of Jinzhou Medical University, Jinzhou, 121000, China
| | - Jiajia Chen
- Department of Oncology, Shengjing Hospital of China Medical University, Shenyang, 110004, China
| | - Teng Ma
- Department of Neurobiology, School of Life Sciences, China Medical University, Shenyang, 110122, China.
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5
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Schilling S, Pradhan A, Heesch A, Helbig A, Blennow K, Koch C, Bertgen L, Koo EH, Brinkmalm G, Zetterberg H, Kins S, Eggert S. Differential effects of familial Alzheimer's disease-causing mutations on amyloid precursor protein (APP) trafficking, proteolytic conversion, and synaptogenic activity. Acta Neuropathol Commun 2023; 11:87. [PMID: 37259128 DOI: 10.1186/s40478-023-01577-y] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2023] [Accepted: 05/04/2023] [Indexed: 06/02/2023] Open
Abstract
The amyloid precursor protein (APP) is a key player in Alzheimer`s disease (AD) and the precursor of the Aβ peptide, which is generated by consecutive cleavages of β- and γ-secretases. Familial Alzheimer's disease (FAD) describes a hereditary subgroup of AD that represents a low percentage of AD cases with an early onset of the disease. Different APP FAD mutations are thought to have qualitatively different effects on its proteolytic conversion. However, few studies have explored the pathogenic and putative physiological differences in more detail. Here, we compared different FAD mutations, located at the β- (Swedish), α- (Flemish, Arctic, Iowa) or γ-secretase (Iberian) cleavage sites. We examined heterologous expression of APP WT and FAD mutants in non-neuronal cells and their impact on presynaptic differentiation in contacting axons of co-cultured neurons. To decipher the underlying molecular mechanism, we tested the subcellular localization, the endocytosis rate and the proteolytic processing in detail by immunoprecipitation-mass spectrometry. Interestingly, we found that only the Iberian mutation showed altered synaptogenic function. Furthermore, the APP Iowa mutant shows significantly decreased α-secretase processing which is in line with our results that APP carrying the Iowa mutation was significantly increased in early endosomes. However, most interestingly, immunoprecipitation-mass spectrometry analysis revealed that the amino acid substitutions of APP FAD mutants have a decisive impact on their processing reflected in altered Aβ profiles. Importantly, N-terminally truncated Aβ peptides starting at position 5 were detected preferentially for APP Flemish, Arctic, and Iowa mutants containing amino acid substitutions around the α-secretase cleavage site. The strongest change in the ratio of Aβ40/Aβ42 was observed for the Iberian mutation while APP Swedish showed a substantial increase in Aβ1-17 peptides. Together, our data indicate that familial AD mutations located at the α-, β-, and γ-secretase cleavage sites show considerable differences in the underlying pathogenic mechanisms.
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Affiliation(s)
- Sandra Schilling
- Department of Human Biology and Human Genetics, University of Kaiserslautern, 67663, Kaiserslautern, Germany
| | - Ajay Pradhan
- Department of Psychiatry and Neurochemistry, Institute of Neuroscience and Physiology, The Sahlgrenska Academy at the University of Gothenburg, Mölndal, Sweden
| | - Amelie Heesch
- Department of Human Biology and Human Genetics, University of Kaiserslautern, 67663, Kaiserslautern, Germany
| | - Andrea Helbig
- Department of Human Biology and Human Genetics, University of Kaiserslautern, 67663, Kaiserslautern, Germany
| | - Kaj Blennow
- Department of Psychiatry and Neurochemistry, Institute of Neuroscience and Physiology, The Sahlgrenska Academy at the University of Gothenburg, Mölndal, Sweden
| | - Christian Koch
- Department of Human Biology and Human Genetics, University of Kaiserslautern, 67663, Kaiserslautern, Germany
| | - Lea Bertgen
- Department of Human Biology and Human Genetics, University of Kaiserslautern, 67663, Kaiserslautern, Germany
| | - Edward H Koo
- San Diego (UCSD), Department of Neuroscience, University of California, La Jolla, CA, 92093-0662, USA
| | - Gunnar Brinkmalm
- Department of Psychiatry and Neurochemistry, Institute of Neuroscience and Physiology, The Sahlgrenska Academy at the University of Gothenburg, Mölndal, Sweden
| | - Henrik Zetterberg
- Department of Psychiatry and Neurochemistry, Institute of Neuroscience and Physiology, The Sahlgrenska Academy at the University of Gothenburg, Mölndal, Sweden
- Clinical Neurochemistry Laboratory, Sahlgrenska University Hospital, Mölndal, Sweden
- Department of Neurodegenerative Disease, UCL Institute of Neurology, Queen Square, London, UK
- UK Dementia Research Institute at UCL, London, UK
- Hong Kong Center for Neurodegenerative Diseases, Clear Water Bay, Hong Kong, China
| | - Stefan Kins
- Department of Human Biology and Human Genetics, University of Kaiserslautern, 67663, Kaiserslautern, Germany
| | - Simone Eggert
- Department of Human Biology and Human Genetics, University of Kaiserslautern, 67663, Kaiserslautern, Germany.
- Department of Neurogenetics, Max Planck Institute for Multidisciplinary Sciences, City-Campus, Hermann-Rein-Str. 3, 37075, Göttingen, Germany.
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Liu H, Guo H, Fang Y, Wang L, Li P. Rational Design of Nitrogen-Doped Carbon Dots for Inhibiting β-Amyloid Aggregation. Molecules 2023; 28:1451. [PMID: 36771112 PMCID: PMC9919344 DOI: 10.3390/molecules28031451] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/26/2022] [Revised: 01/12/2023] [Accepted: 01/15/2023] [Indexed: 02/05/2023] Open
Abstract
The fibrillization and abnormal aggregation of β-amyloid (Aβ) peptides are commonly recognized risk factors for Alzheimer's disease (AD) brain, and require an effective strategy to inhibit the Aβ deposition and treat AD. Herein, we designed and synthesized nitrogen-doped carbon dots (N-CDs) as an Aβ-targeted probe, which exhibits the capacity of inhibiting the 1-42 Aβ (Aβ1-42) self-assembly in vitro. The N-CDs exhibited orange emission with an emission wavelength of 570 nm, which demonstrates their excellent optical properties with excitation-independent behavior. Meanwhile, the N-CDs have spherical morphologies with an average size of 2.2 nm, whose surface enriches the amino, carboxyl, and hydroxyl groups. These preparties are conducive to improving their biological water solubility and provide a large number of chemical bonds for further interaction with proteins. Contrary to this, the kinetic process, size evolutions, and morphologies changes of Aβ1-42 were inhibited in the presence of N-CDs in the determination of a thioflavin T assay, dynamic light scattering, transmission electron microscope, etc. Finally, the safety application of N-CDs on Aβ1-42-induced cytotoxicity was further demonstrated via in vitro cytotoxicity experiments. This work demonstrates the effective outcome of suppressing Aβ aggregation, which provides a new view into the high-efficiency and low-cytotoxicity strategy in AD theranostics.
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Affiliation(s)
- Hong Liu
- Department of Neurovascular, Shanghai Fourth People’s Hospital, Tongji University School of Medicine, Shanghai 200434, China
- Department of Neurology, Shanghai East Hospital, Tongji University School of Medicine, Shanghai 200120, China
| | - Huazhang Guo
- Institute of Nanochemistry and Nanobiology, School of Environmental and Chemical Engineering, Shanghai University, Shanghai 200444, China
| | - Yibin Fang
- Department of Neurovascular, Shanghai Fourth People’s Hospital, Tongji University School of Medicine, Shanghai 200434, China
| | - Liang Wang
- Institute of Nanochemistry and Nanobiology, School of Environmental and Chemical Engineering, Shanghai University, Shanghai 200444, China
| | - Peng Li
- Department of Neurovascular, Shanghai Fourth People’s Hospital, Tongji University School of Medicine, Shanghai 200434, China
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7
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Hossain MS, Ramasamy VS, Park IS. Involvement of calcium ions in amyloid-β-induced lamin fragmentation. BIOCHIMICA ET BIOPHYSICA ACTA. MOLECULAR CELL RESEARCH 2023; 1870:119383. [PMID: 36302464 DOI: 10.1016/j.bbamcr.2022.119383] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/14/2022] [Revised: 09/07/2022] [Accepted: 10/17/2022] [Indexed: 11/13/2022]
Abstract
Amyloid-β (Aβ) peptide, the main pathogenic peptide in Alzheimer's disease, has been shown to induce an increase in cytoplasmic calcium concentration (CCC). In the current study, we explored the cytotoxic signal transduction pathway in 42-amino-acid Aβ (Aβ42)-treated HeLa cells in relation to the increase in CCC. The increase in CCC was prominent in cells treated twice with oligomeric Aβ42. We previously showed that double treatment also promoted Aβ-induced lamin fragmentation (AILF), which appears to be mediated by cathepsin L. Apoptotic caspase activation was a downstream event of AILF. The Ca2+ chelator BAPTA-AM suppressed cell death, cathepsin L activation, AILF, and caspase activation in Aβ-treated cells. These results indicate that Aβ42 induces an increase in CCC, which is an event upstream of the cytotoxic processes. The products of AILF are different from those produced by other cell death-inducing agents, such as staurosporine, which induces caspase-6-mediated lamin fragmentation (CMLF). CMLF was unaffected by BAPTA-AM and was not detected in cells treated with Aβ42, indicating that Aβ42 peptide induced a specific cytotoxic pathway involving AILF via increased CCC. We confirmed that the same processes (except caspase activation) operated in Aβ42-treated neuroblastoma SH-SY5Y cells.
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Affiliation(s)
- Md Selim Hossain
- Department of Biomedical Sciences, Chosun University, Gwangju, Republic of Korea
| | | | - Il-Seon Park
- Department of Biomedical Sciences, Chosun University, Gwangju, Republic of Korea; Department of Cellular and Molecular Medicine, Chosun University, Gwangju, Republic of Korea.
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8
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Rosenberry TL, Zhou HX, Stagg SM, Paravastu AK. Oligomer Formation by Amyloid-β42 in a Membrane-Mimicking Environment in Alzheimer's Disease. Molecules 2022; 27:8804. [PMID: 36557940 PMCID: PMC9781152 DOI: 10.3390/molecules27248804] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2022] [Revised: 11/17/2022] [Accepted: 11/23/2022] [Indexed: 12/15/2022] Open
Abstract
The brains of Alzheimer's disease (AD) patients contain numerous amyloid plaques that are diagnostic of the disease. The plaques are primarily composed of the amyloidogenic peptides proteins Aβ40 and Aβ42, which are derived by the processing of the amyloid pre-cursor protein (APP) by two proteases called β-secretase and γ-secretase. Aβ42 differs from Aβ40 in having two additional hydrophobic amino acids, ILE and ALA, at the C-terminus. A small percentage of AD is autosomal dominant (ADAD) and linked either to the genes for the presenilins, which are part of γ-secretase, or APP. Because ADAD shares most pathogenic features with widespread late-onset AD, Aβ peptides have become the focus of AD research. Fibrils formed by the aggregation of these peptides are the major component of plaques and were initially targeted in AD therapy. However, the fact that the abundance of plaques does not correlate well with cognitive decline in AD patients has led investigators to examine smaller Aβ aggregates called oligomers. The low levels and heterogeneity of Aβ oligomers have made the determination of their structures difficult, but recent structure determinations of oligomers either formed or initiated in detergents have been achieved. We report here on the structures of these oligomers and suggest how they may be involved in AD.
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Affiliation(s)
- Terrone L. Rosenberry
- The Departments of Neuroscience and Pharmacology, Mayo Clinic, Jacksonville, FL 32224, USA
| | - Huan-Xiang Zhou
- Departments of Chemistry and Physics, University of Illinois Chicago, Chicago, IL 60608, USA
| | - Scott M. Stagg
- Institute of Molecular Biophysics, Florida State University, Tallahassee, FL 32306, USA
- Department of Biological Sciences, Florida State University, Tallahassee, FL 32306, USA
| | - Anant K. Paravastu
- School of Chemical and Biomolecular Engineering, Georgia Institute of Technology, 311 Ferst Drive NW, Atlanta, GA 30332, USA
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9
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Howitz WJ, Guaglianone G, McKnelly KJ, Haduong K, Ashby SN, Laayouni M, Nowick JS. Macrocyclic Peptides Derived from Familial Alzheimer's Disease Mutants Show Charge-Dependent Oligomeric Assembly and Toxicity. ACS Chem Neurosci 2022; 13:714-720. [PMID: 35191689 PMCID: PMC9042422 DOI: 10.1021/acschemneuro.1c00833] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022] Open
Abstract
This work probes the role of charge in the oligomeric assembly, toxicity, and membrane destabilization of a series of peptides derived from Aβ and the E22Q and E22K familial mutants. In the mutant Aβ peptides, an acidic residue (E) is replaced with either a neutral or basic residue (Q or K), thus altering the net charge of the peptide. Acetylation at peripheral positions permits modulation of charge of the peptides and allows investigation of the role of charge in their oligomeric assembly, cytotoxicity, and membrane disruption. Peptides with the same net charge generally behave similarly even if the amino acid residue at position 22 differs. As the net charge of the peptide decreases, so does the extent of assembly, cytotoxicity, and membrane destabilization, which were determined using sodium dodecyl sulfate-polyacrylamide gel electrophoresis, lactate dehydrogenase (LDH)-release assays with SH-SY5Y cells, and dye leakage assays using liposomes. These findings suggest that the charge of the amino acid side chain, rather than its size or hydrophobicity, accounts for the differences in the oligomeric assembly and toxicity of the E22 familial mutants of Aβ.
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Affiliation(s)
- William J Howitz
- Department of Chemistry, University of California, Irvine, Irvine, California 92697, United States
| | - Gretchen Guaglianone
- Department of Chemistry, University of California, Irvine, Irvine, California 92697, United States
| | - Kate J McKnelly
- Department of Chemistry, University of California, Irvine, Irvine, California 92697, United States
| | - Katelyn Haduong
- Department of Chemistry, University of California, Irvine, Irvine, California 92697, United States
| | - Shareen N Ashby
- Department of Chemistry, University of California, Irvine, Irvine, California 92697, United States
| | - Mohamed Laayouni
- Department of Chemistry, University of California, Irvine, Irvine, California 92697, United States
| | - James S Nowick
- Department of Chemistry, University of California, Irvine, Irvine, California 92697, United States.,Department of Pharmaceutical Sciences, University of California, Irvine, Irvine, California 92697, United States
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Das A. Systematic Search for a Predictor for the Clinical Observables of Alzheimer's Disease. J Phys Chem B 2021; 125:12177-12186. [PMID: 34723517 DOI: 10.1021/acs.jpcb.1c06725] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
Abstract
One of the prevailing life-threatening incurable neurodegenerative diseases that are presently endangering human society as a whole, and hence, baffling the entire spectrum of the scientific and pharmaceutical world, is Alzheimer's disease (AD). AD is a manifestation of self-assembly of both wild-type (sporadic) and mutated (familial) forms of the amyloid-β peptide, a proteolytic product of the amyloid precursor protein, where the self-assembly results in the genesis of pathogenic fibrillar aggregates. Currently prevailing diagnostic and hence therapeutic challenges originate from the unavailability of a specific predictor for clinical observables. The continuous emergence of novel pathogenic mutants with unpredictable phenotypes adds immensely to the nonspecific nature of the problem. The current research reports a simple physical parameter, the binding affinity of a protofilament to its protofibril, which predicts the clinical observables of familial AD with astounding accuracy and more importantly, without any adjustable parameters.
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Affiliation(s)
- Atanu Das
- Physical and Materials Chemistry Division, CSIR-National Chemical Laboratory, Dr. Homi Bhabha Road, Pune, Maharashtra 411 008, India.,Academy of Scientific and Innovative Research (AcSIR), Ghaziabad 201002, India
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Bai Y, Liu D, Zhang H, Wang Y, Wang D, Cai H, Wen H, Yuan G, An H, Wang Y, Shi T, Wang Z. N-salicyloyl tryptamine derivatives as potential therapeutic agents for Alzheimer's disease with neuroprotective effects. Bioorg Chem 2021; 115:105255. [PMID: 34435574 DOI: 10.1016/j.bioorg.2021.105255] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2021] [Revised: 08/05/2021] [Accepted: 08/05/2021] [Indexed: 12/20/2022]
Abstract
Alzheimer's disease (AD) has become a serious threat to the developed nations with burgeoning patients and annual costs on health care system in modern society. Neuroinflammation, as one of the specific biochemical factors in the progress of neurodegeneration diseases, performs a crucial role in the pathogenesis and development of AD. Therefore, it is of great significance to develop effective anti-neuroinflammatory strategies for the treatment of AD. N-salicyloyl tryptamine derivatives were previously reported and demonstrated that possessed great potential anti-neuroinflammatory effects and favorable blood-brain barrier (BBB) permeation. Herein, a series of novel N-salicyloyl tryptamine derivatives were synthesized and their anti-AD potential was evaluated both in vitro and in vivo. Among them, L7 performed well anti-neuroinflammatory effects and excellent neuroprotective effects, as well as little toxicity. To lucubrate its potential for the treatment of AD, behavior tests including morris water maze (MWM), eight-arm radial maze, open field test and novel object recognition (NOR) test were carried out and the results showed that L7 could remarkably improve Aβ-induced cognitive impairment. Moreover, the mechanism of action of L7 on improving Aβ-induced AD was preliminarily investigated, and the results uncovered that the neuroprotective effects of L7 was might exerte via intervening Aβ-induced pyroptosis through NLRP3-caspase-1-GSDMD axis and ameliorating neuronal apoptosis by mitochondrial apoptosis pathway. Besides, the distribution of Aβ plaques in brain tissues were detected by immunohistochemical (IHC) assay and the results indicated that L7 could significantly attenuate the deposition of Aβ plaques in the brain.
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Affiliation(s)
- Yinliang Bai
- State Key Laboratory of Applied Organic Chemistry, College of Chemistry and Chemical Engineering, Lanzhou University, Lanzhou 730000, China; Lanzhou University Second Hospital, Lanzhou 730030, China
| | - Dan Liu
- School of Pharmacy, Lanzhou University, West Donggang Road, No. 199, Lanzhou 730000, China
| | - Honghua Zhang
- School of Pharmacy, Lanzhou University, West Donggang Road, No. 199, Lanzhou 730000, China
| | - Yuying Wang
- State Key Laboratory of Applied Organic Chemistry, College of Chemistry and Chemical Engineering, Lanzhou University, Lanzhou 730000, China
| | - Degui Wang
- Department of Anatomy and Histology, School of Basic Medical Sciences, Lanzhou University, Lanzhou 730030, China
| | - Hongbin Cai
- Lanzhou University Second Hospital, Lanzhou 730030, China
| | - Huaixiu Wen
- Northwest Institute of Plateau Biology, Chinese Academy of Sciences, Xining 810008, China
| | - Guoqiang Yuan
- Lanzhou University Second Hospital, Lanzhou 730030, China
| | - Hui An
- Lanzhou University Second Hospital, Lanzhou 730030, China
| | - Yali Wang
- Lanzhou University Second Hospital, Lanzhou 730030, China
| | - Tao Shi
- School of Pharmacy, Lanzhou University, West Donggang Road, No. 199, Lanzhou 730000, China.
| | - Zhen Wang
- School of Pharmacy, Lanzhou University, West Donggang Road, No. 199, Lanzhou 730000, China; State Key Laboratory of Applied Organic Chemistry, College of Chemistry and Chemical Engineering, Lanzhou University, Lanzhou 730000, China; School of Pharmaceutical Science, University of South China, Hengyang 421001, China.
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12
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Illes-Toth E, Meisl G, Rempel DL, Knowles TPJ, Gross ML. Pulsed Hydrogen-Deuterium Exchange Reveals Altered Structures and Mechanisms in the Aggregation of Familial Alzheimer's Disease Mutants. ACS Chem Neurosci 2021; 12:1972-1982. [PMID: 33988976 DOI: 10.1021/acschemneuro.1c00072] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022] Open
Abstract
Mutations of the Amyloid Precursor Protein, from which the amyloid β peptide Aβ42 is cleaved, are associated with familial Alzheimer's disease. The disease-relevant familial mutations include the Arctic (E22G), Iowa (D23N), Italian (E22K), Dutch (E22Q), Japanese (D7N), English (D6R), and Flemish (A21G) variants. A detailed mechanistic understanding of the aggregation behavior of the mutant peptides at the residue level is, however, still lacking. We report here a study of the aggregation kinetics of these mutants in vitro by pulsed hydrogen-deuterium exchange mass spectrometry (HDX-MS) to obtain a temporally and sequence resolved picture of their self-assembly. For all variants, HDX occurs to give a bimodal distribution representing two soluble classes of aggregates, one protected and one solvent-exposed. There is no evidence of other classes of structural intermediates within the detection limits of the HDX approach. The fractional changes in the bimodal exchange profiles for several regions of Aβ42 reveal that the central and C-terminal peptides gain protection upon fibril formation, whereas the N-terminal regions remain largely solvent-accessible. For these mutants, all peptide fragments follow the same kinetics, acquiring solvent protection at the same time, further supporting that there are no significant populations of intermediate species under our experimental conditions. The results demonstrate the potential of pulsed HDX-MS for resolving the region-specific aggregation behavior of Aβ42 isoforms in solution where X-ray crystallography and solid-state NMR (ssNMR) are challenged.
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Affiliation(s)
- Eva Illes-Toth
- Washington University in St. Louis, Department of Chemistry, St. Louis, Missouri 63130, United States
| | - Georg Meisl
- University of Cambridge, Department of Chemistry, Lensfield Road, Cambridge CB2 1EW, UK
| | - Don L. Rempel
- Washington University in St. Louis, Department of Chemistry, St. Louis, Missouri 63130, United States
| | - Tuomas P. J. Knowles
- University of Cambridge, Department of Chemistry, Lensfield Road, Cambridge CB2 1EW, UK
| | - Michael L. Gross
- Washington University in St. Louis, Department of Chemistry, St. Louis, Missouri 63130, United States
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13
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An evaluation of the self-assembly enhancing properties of cell-derived hexameric amyloid-β. Sci Rep 2021; 11:11570. [PMID: 34078941 PMCID: PMC8172837 DOI: 10.1038/s41598-021-90680-y] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2020] [Accepted: 05/04/2021] [Indexed: 12/17/2022] Open
Abstract
A key hallmark of Alzheimer’s disease is the extracellular deposition of amyloid plaques composed primarily of the amyloidogenic amyloid-β (Aβ) peptide. The Aβ peptide is a product of sequential cleavage of the Amyloid Precursor Protein, the first step of which gives rise to a C-terminal Fragment (C99). Cleavage of C99 by γ-secretase activity releases Aβ of several lengths and the Aβ42 isoform in particular has been identified as being neurotoxic. The misfolding of Aβ leads to subsequent amyloid fibril formation by nucleated polymerisation. This requires an initial and critical nucleus for self-assembly. Here, we identify and characterise the composition and self-assembly properties of cell-derived hexameric Aβ42 and show its assembly enhancing properties which are dependent on the Aβ monomer availability. Identification of nucleating assemblies that contribute to self-assembly in this way may serve as therapeutic targets to prevent the formation of toxic oligomers.
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14
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Masuda Y. Bioactive 3D structures of naturally occurring peptides and their application in drug design. Biosci Biotechnol Biochem 2021; 85:24-32. [PMID: 33577656 DOI: 10.1093/bbb/zbaa008] [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: 08/25/2020] [Accepted: 09/10/2020] [Indexed: 11/14/2022]
Abstract
Naturally occurring peptides form unique 3D structures, which are critical for their bioactivities. To gain useful insights into drug design, the relationship between the 3D structure and bioactivity of the peptides has been studied. Solid-state nuclear magnetic resonance (NMR) analysis of the 42-residue amyloid β-protein (Aβ42) suggested the presence of toxic conformers with a turn structure at positions 22 and 23 in the aggregates. Antibodies specific to this turn structure could be utilized for immunotherapy and early diagnosis of Alzheimer's disease. Solution NMR analysis of apratoxin A, a cyclic depsipeptide with potent cytotoxicity, proposed an accurate structural model with an important bend structure, which led to the development of highly active mimetics. X-ray crystal analysis of PF1171F, a cyclic hexapeptide with insecticidal activity, indicated the formation of 4 intramolecular hydrogen bonds, which play an important role in cell membrane permeability of PF1171F.
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Affiliation(s)
- Yuichi Masuda
- Graduate School of Bioresources, Mie University, Tsu, Japan
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15
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Tanaka F, Shibata K, Monobe Y, Akagi KI, Masuda Y. Design and synthesis of β-strand-fixed peptides inhibiting aggregation of amyloid β-protein. Bioorg Med Chem 2020; 28:115676. [DOI: 10.1016/j.bmc.2020.115676] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2020] [Revised: 07/13/2020] [Accepted: 07/17/2020] [Indexed: 12/26/2022]
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16
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Han C, Yang Y, Guan Q, Zhang X, Shen H, Sheng Y, Wang J, Zhou X, Li W, Guo L, Jiao Q. New mechanism of nerve injury in Alzheimer's disease: β-amyloid-induced neuronal pyroptosis. J Cell Mol Med 2020; 24:8078-8090. [PMID: 32521573 PMCID: PMC7348172 DOI: 10.1111/jcmm.15439] [Citation(s) in RCA: 105] [Impact Index Per Article: 26.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2020] [Revised: 05/03/2020] [Accepted: 05/12/2020] [Indexed: 12/28/2022] Open
Abstract
The present study was designed to investigate the role of β-amyloid (Aβ1-42 ) in inducing neuronal pyroptosis and its mechanism. Mice cortical neurons (MCNs) were used in this study, LPS + Nigericin was used to induce pyroptosis in MCNs (positive control group), and Aβ1-42 was used to interfere with MCNs. In addition, propidium iodide (PI) staining was used to examine cell permeability, lactate dehydrogenase (LDH) release assay was employed to detect cytotoxicity, immunofluorescence (IF) staining was used to investigate the expression level of the key protein GSDMD, Western blot was performed to detect the expression levels of key proteins, and enzyme-linked immunosorbent assay (ELISA) was utilized to determine the expression levels of inflammatory factors in culture medium, including IL-1β, IL-18 and TNF-α. Small interfering RNA (siRNA) was used to silence the mRNA expression of caspase-1 and GSDMD, and Aβ1-42 was used to induce pyroptosis, followed by investigation of the role of caspase-1-mediated GSDMD cleavage in pyroptosis. In addition, necrosulfonamide (NSA), an inhibitor of GSDMD oligomerization, was used for pre-treatment, and Aβ1-42 was subsequently used to observe the pyroptosis in MCNs. Finally, AAV9-siRNA-caspase-1 was injected into the tail vein of APP/PS1 double transgenic mice (Alzheimer's disease mice) for caspase-1 mRNA inhibition, followed by observation of behavioural changes in mice and measurement of the expression of inflammatory factors and pyroptosis-related protein. As results, Aβ1-42 could induce pyroptosis in MCNs, increase cell permeability and enhance LDH release, which were similar to the LPS + Nigericin-induced pyroptosis. Meanwhile, the expression levels of cellular GSDMD and p30-GSDMD were up-regulated, the levels of NLRP3 inflammasome and GSDMD-cleaved protein caspase-1 were up-regulated, and the levels of inflammatory factors in the medium were also up-regulated. siRNA intervention in caspase-1 or GSDMD inhibited Aβ1-42 -induced pyroptosis, and NSA pre-treatment also caused the similar inhibitory effects. The behavioural ability of Alzheimer's disease (AD) mice was relieved after the injection of AAV9-siRNA-caspase-1, and the expression of pyroptosis-related protein in the cortex and hippocampus was down-regulated. In conclusion, Aβ1-42 could induce pyroptosis by GSDMD protein, and NLRP3-caspase-1 signalling was an important signal to mediate GSDMD cleavage, which plays an important role in Aβ1-42 -induced pyroptosis in neurons. Therefore, GSDMD is expected to be a novel therapeutic target for AD.
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Affiliation(s)
- Chenyang Han
- State Key Laboratory of Pharmaceutical BiotechnologySchool of Life ScienceNanjing UniversityNanjingChina
- Department of PharmacyThe Second Affiliated Hospital of Jiaxing UniversityJiaxingChina
| | - Yi Yang
- Department of PharmacyThe Second Affiliated Hospital of Jiaxing UniversityJiaxingChina
| | - Qiaobing Guan
- Department of NeurologyThe Second Affiliated Hospital of Jiaxing UniversityJiaxingChina
| | - Xiaoling Zhang
- Department of NeurologyThe Second Affiliated Hospital of Jiaxing UniversityJiaxingChina
| | - Heping Shen
- Department of NeurologyThe Second Affiliated Hospital of Jiaxing UniversityJiaxingChina
| | - Yongjia Sheng
- Department of PharmacyThe Second Affiliated Hospital of Jiaxing UniversityJiaxingChina
| | - Jin Wang
- Department of PharmacyThe Second Affiliated Hospital of Jiaxing UniversityJiaxingChina
| | - Xiaohong Zhou
- Department of PharmacyThe Second Affiliated Hospital of Jiaxing UniversityJiaxingChina
| | - Wenyan Li
- Department of PharmacyThe Second Affiliated Hospital of Jiaxing UniversityJiaxingChina
| | - Li Guo
- Department of Center LaboratoryThe Second Affiliated Hospital of Jiaxing UniversityJiaxingChina
| | - Qingcai Jiao
- State Key Laboratory of Pharmaceutical BiotechnologySchool of Life ScienceNanjing UniversityNanjingChina
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17
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Price D, Dorandish S, Williams A, Iwaniec B, Stephens A, Marshall K, Guthrie J, Heyl D, Evans HG. Humanin Blocks the Aggregation of Amyloid-β Induced by Acetylcholinesterase, an Effect Abolished in the Presence of IGFBP-3. Biochemistry 2020; 59:1981-2002. [PMID: 32383868 PMCID: PMC8193794 DOI: 10.1021/acs.biochem.0c00274] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
It is known that the humanin (HN) peptide binding to amyloid-β (Aβ) protects against its cytotoxic effects, while acetylcholinesterase (AChE) binding to Aβ increases its aggregation and cytotoxicity. HN is also known to bind the insulin-like growth factor binding protein-3 (IGFBP-3). Here, we examined the regulation of Aβ conformations by HN, AChE, and IGFBP-3 both in vitro and in the conditioned media from A549 and H1299 lung cancer cells. Our in vitro results showed the following: IGFBP-3 binds HN and blocks it from binding Aβ in the absence or presence of AChE; HN and AChE can simultaneously bind Aβ but not when in the presence of IGFBP-3; HN is unable to reduce the aggregation of Aβ in the presence of IGFBP-3; and HN abolishes the aggregation of Aβ induced by the addition of AChE in the absence of IGFBP-3. In the media, AChE and HN can simultaneously bind Aβ. While both AChE and HN are detected when using 6E10 Aβ antibodies, only AChE is detected when using the Aβ 17-24 antibody 4G8, the anti-oligomer A11, and the anti-amyloid fibril LOC antibodies. No signal was observed for IGFBP-3 with any of the anti-amyloid antibodies used. Exogenously added IGFBP-3 reduced the amount of HN found in a complex when using 6E10 antibodies and correlated with a concomitant increase in the amyloid oligomers. Immunodepletion of HN from the media of the A549 and H1299 cells increased the relative abundance of the oligomer vs the total amount of Aβ, the A11-positive prefibrillar oligomers, and to a lesser extent the LOC-positive fibrillar oligomers, and was also correlated with diminished cell viability and increased apoptosis.
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Affiliation(s)
- Deanna Price
- Department of Chemistry, Eastern Michigan University, Ypsilanti, Michigan 48197, United States
| | - Sadaf Dorandish
- Department of Chemistry, Eastern Michigan University, Ypsilanti, Michigan 48197, United States
| | - Asana Williams
- Department of Chemistry, Eastern Michigan University, Ypsilanti, Michigan 48197, United States
| | - Brandon Iwaniec
- Department of Chemistry, Eastern Michigan University, Ypsilanti, Michigan 48197, United States
| | - Alexis Stephens
- Department of Chemistry, Eastern Michigan University, Ypsilanti, Michigan 48197, United States
| | - Keyan Marshall
- Department of Chemistry, Eastern Michigan University, Ypsilanti, Michigan 48197, United States
| | - Jeffrey Guthrie
- Department of Chemistry, Eastern Michigan University, Ypsilanti, Michigan 48197, United States
| | - Deborah Heyl
- Department of Chemistry, Eastern Michigan University, Ypsilanti, Michigan 48197, United States
| | - Hedeel Guy Evans
- Department of Chemistry, Eastern Michigan University, Ypsilanti, Michigan 48197, United States
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18
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D’Argenio V, Sarnataro D. New Insights into the Molecular Bases of Familial Alzheimer's Disease. J Pers Med 2020; 10:jpm10020026. [PMID: 32325882 PMCID: PMC7354425 DOI: 10.3390/jpm10020026] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2020] [Revised: 04/14/2020] [Accepted: 04/17/2020] [Indexed: 12/11/2022] Open
Abstract
Like several neurodegenerative disorders, such as Prion and Parkinson diseases, Alzheimer's disease (AD) is characterized by spreading mechanism of aggregated proteins in the brain in a typical "prion-like" manner. Recent genetic studies have identified in four genes associated with inherited AD (amyloid precursor protein-APP, Presenilin-1, Presenilin-2 and Apolipoprotein E), rare mutations which cause dysregulation of APP processing and alterations of folding of the derived amyloid beta peptide (A). Accumulation and aggregation of A in the brain can trigger a series of intracellular events, including hyperphosphorylation of tau protein, leading to the pathological features of AD. However, mutations in these four genes account for a small of the total genetic risk for familial AD (FAD). Genome-wide association studies have recently led to the identification of additional AD candidate genes. Here, we review an update of well-established, highly penetrant FAD-causing genes with correlation to the protein misfolding pathway, and novel emerging candidate FAD genes, as well as inherited risk factors. Knowledge of these genes and of their correlated biochemical cascade will provide several potential targets for treatment of AD and aging-related disorders.
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Affiliation(s)
- Valeria D’Argenio
- CEINGE-Biotecnologie Avanzate scarl, via G. Salvatore 486, 80145 Naples, Italy
- Department of Human Sciences and Quality of Life Promotion, San Raffaele Open University, via di val Cannuta 247, 00166 Rome, Italy
- Correspondence: (V.D.); (D.S.); Tel.: +39-081-3737909 (V.D.); +39-081-7464575 (D.S.)
| | - Daniela Sarnataro
- Department of Molecular Medicine and Medical Biotechnology, Federico II University, via S. Pansini 5, 80131 Naples, Italy
- Correspondence: (V.D.); (D.S.); Tel.: +39-081-3737909 (V.D.); +39-081-7464575 (D.S.)
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19
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Conformational Characterization of Native and L17A/F19A-Substituted Dutch-Type β-Amyloid Peptides. Int J Mol Sci 2020; 21:ijms21072571. [PMID: 32272787 PMCID: PMC7177254 DOI: 10.3390/ijms21072571] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/29/2020] [Revised: 04/06/2020] [Accepted: 04/06/2020] [Indexed: 01/26/2023] Open
Abstract
Some mutations which occur in the α/β-discordant region (resides 15 to 23) of β-amyloid peptide (Aβ) lead to familial Alzheimer’s disease (FAD). In vitro studies have shown that these genetic mutations could accelerate Aβ aggregation. We recently showed that mutations in this region could alter the structural propensity, resulting in a different aggregative propensity of Aβ. Whether these genetic mutations display similar effects remains largely unknown. Here, we characterized the structural propensity and aggregation kinetics of Dutch-type Aβ40 (Aβ40(E22Q)) and its L17A/F19A-substituted mutant (Aβ40(L17A/F19A/E22Q)) using circular dichroism spectroscopy, nuclear magnetic spectroscopy, and thioflavin T fluorescence assay. In comparison with wild-type Aβ40, we found that Dutch-type mutation, unlike Artic-type mutation (E22G), does not reduce the α-helical propensity of the α/β-discordant region in sodium dodecyl sulfate micellar solution. Moreover, we found that Aβ40(L17A/F19A/E22Q) displays a higher α-helical propensity of the α/β-discordant region and a slower aggregation rate than Aβ40(E22Q), suggesting that the inhibition of aggregation might be via increasing the α-helical propensity of the α/β-discordant region, similar to that observed in wild-type and Artic-type Aβ40. Taken together, Dutch-type and Artic-type mutations adopt different mechanisms to promote Aβ aggregation, however, the L17A/F19A mutation could increase the α-helical propensities of both Dutch-type and Artic-type Aβ40 and inhibit their aggregation.
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20
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Wille H, Dorosh L, Amidian S, Schmitt-Ulms G, Stepanova M. Combining molecular dynamics simulations and experimental analyses in protein misfolding. ADVANCES IN PROTEIN CHEMISTRY AND STRUCTURAL BIOLOGY 2020; 118:33-110. [PMID: 31928730 DOI: 10.1016/bs.apcsb.2019.10.001] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
The fold of a protein determines its function and its misfolding can result in loss-of-function defects. In addition, for certain proteins their misfolding can lead to gain-of-function toxicities resulting in protein misfolding diseases such as Alzheimer's, Parkinson's, or the prion diseases. In all of these diseases one or more proteins misfold and aggregate into disease-specific assemblies, often in the form of fibrillar amyloid deposits. Most, if not all, protein misfolding diseases share a fundamental molecular mechanism that governs the misfolding and subsequent aggregation. A wide variety of experimental methods have contributed to our knowledge about misfolded protein aggregates, some of which are briefly described in this review. The misfolding mechanism itself is difficult to investigate, as the necessary timescale and resolution of the misfolding events often lie outside of the observable parameter space. Molecular dynamics simulations fill this gap by virtue of their intrinsic, molecular perspective and the step-by-step iterative process that forms the basis of the simulations. This review focuses on molecular dynamics simulations and how they combine with experimental analyses to provide detailed insights into protein misfolding and the ensuing diseases.
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Affiliation(s)
- Holger Wille
- Department of Biochemistry, University of Alberta, Edmonton, Canada; Centre for Prions and Protein Folding Diseases, University of Alberta, Edmonton, Canada; Neuroscience and Mental Health Institute, University of Alberta, Edmonton, Canada
| | - Lyudmyla Dorosh
- Department of Electrical and Computer Engineering, University of Alberta, Edmonton, Canada
| | - Sara Amidian
- Department of Biochemistry, University of Alberta, Edmonton, Canada; Centre for Prions and Protein Folding Diseases, University of Alberta, Edmonton, Canada
| | - Gerold Schmitt-Ulms
- Laboratory Medicine and Pathobiology, University of Toronto, Toronto, Canada
| | - Maria Stepanova
- Department of Electrical and Computer Engineering, University of Alberta, Edmonton, Canada
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21
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Dorsey MP, Nguelifack BM, Yates EA. Colorimetric Detection of Mutant β-Amyloid(1–40) Membrane-Active Aggregation with Biosensing Vesicles. ACS APPLIED BIO MATERIALS 2019; 2:4966-4977. [DOI: 10.1021/acsabm.9b00694] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Affiliation(s)
- Michael P. Dorsey
- Department of Chemistry, United States Naval Academy, 572M Holloway Road, Annapolis, Maryland 21402, United States
| | - Brice M. Nguelifack
- Department of Mathematics, United States Naval Academy, 572C Holloway Road, Annapolis, Maryland 21402, United States
| | - Elizabeth A. Yates
- Department of Chemistry, United States Naval Academy, 572M Holloway Road, Annapolis, Maryland 21402, United States
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22
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Bi C, Bi S, Li B. Processing of Mutant β-Amyloid Precursor Protein and the Clinicopathological Features of Familial Alzheimer's Disease. Aging Dis 2019; 10:383-403. [PMID: 31011484 PMCID: PMC6457050 DOI: 10.14336/ad.2018.0425] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2018] [Accepted: 04/25/2018] [Indexed: 12/20/2022] Open
Abstract
Alzheimer's disease (AD) is a complex, multifactorial disease involving many pathological mechanisms. Nonetheless, single pathogenic mutations in amyloid precursor protein (APP) or presenilin 1 or 2 can cause AD with almost all of the clinical and neuropathological features, and therefore, we believe an important mechanism of pathogenesis in AD could be revealed from examining pathogenic APP missense mutations. A comprehensive review of the literature, including clinical, neuropathological, cellular and animal model data, was conducted through PubMed and the databases of Alzforum mutations, HGMD, UniProt, and AD&FTDMDB. Pearson correlation analysis combining the clinical and neuropathological data and aspects of mutant APP processing in cellular models was performed. We find that an increase in Aβ42 has a significant positive correlation with the appearance of neurofibrillary tangles (NFTs) and tends to cause an earlier age of AD onset, while an increase in Aβ40 significantly increases the age at death. The increase in the α-carboxyl terminal fragment (CTF) has a significantly negative correlation with the age of AD onset, and β-CTF has a similar effect without statistical significance. Animal models show that intracellular Aβ is critical for memory defects. Based on these results and the fact that amyloid plaque burden correlates much less well with cognitive impairment than do NFT counts, we propose a "snowball hypothesis": the accumulation of intraneuronal NFTs caused by extracellular Aβ42 and the increase in intraneuronal APP proteolytic products (CTFs and Aβs) could cause cellular organelle stress that leads to neurodegeneration in AD, which then resembles the formation of abnormal protein "snowballs" both inside and outside of neurons.
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Affiliation(s)
- Christopher Bi
- Washington Institute for Health Sciences, Arlington, VA 22203, USA
| | - Stephanie Bi
- Washington Institute for Health Sciences, Arlington, VA 22203, USA
| | - Bin Li
- Washington Institute for Health Sciences, Arlington, VA 22203, USA
- Department of Biochemistry and Molecular & Cellular Biology, Georgetown University Medical Center, Washington DC 20057, USA
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23
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Ge L, Tian Y. Fluorescence Lifetime Imaging of p-tau Protein in Single Neuron with a Highly Selective Fluorescent Probe. Anal Chem 2019; 91:3294-3301. [DOI: 10.1021/acs.analchem.8b03992] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Affiliation(s)
- Lihong Ge
- Department of Chemistry, School of Chemistry and Molecular Engineering, East China Normal University, Dongchuan Road 500, Shanghai 200241, China
| | - Yang Tian
- Department of Chemistry, School of Chemistry and Molecular Engineering, East China Normal University, Dongchuan Road 500, Shanghai 200241, China
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24
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Coskuner-Weber O, Uversky VN. Insights into the Molecular Mechanisms of Alzheimer's and Parkinson's Diseases with Molecular Simulations: Understanding the Roles of Artificial and Pathological Missense Mutations in Intrinsically Disordered Proteins Related to Pathology. Int J Mol Sci 2018; 19:E336. [PMID: 29364151 PMCID: PMC5855558 DOI: 10.3390/ijms19020336] [Citation(s) in RCA: 44] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2017] [Revised: 01/14/2018] [Accepted: 01/16/2018] [Indexed: 12/18/2022] Open
Abstract
Amyloid-β and α-synuclein are intrinsically disordered proteins (IDPs), which are at the center of Alzheimer's and Parkinson's disease pathologies, respectively. These IDPs are extremely flexible and do not adopt stable structures. Furthermore, both amyloid-β and α-synuclein can form toxic oligomers, amyloid fibrils and other type of aggregates in Alzheimer's and Parkinson's diseases. Experimentalists face challenges in investigating the structures and thermodynamic properties of these IDPs in their monomeric and oligomeric forms due to the rapid conformational changes, fast aggregation processes and strong solvent effects. Classical molecular dynamics simulations complement experiments and provide structural information at the atomic level with dynamics without facing the same experimental limitations. Artificial missense mutations are employed experimentally and computationally for providing insights into the structure-function relationships of amyloid-β and α-synuclein in relation to the pathologies of Alzheimer's and Parkinson's diseases. Furthermore, there are several natural genetic variations that play a role in the pathogenesis of familial cases of Alzheimer's and Parkinson's diseases, which are related to specific genetic defects inherited in dominant or recessive patterns. The present review summarizes the current understanding of monomeric and oligomeric forms of amyloid-β and α-synuclein, as well as the impacts of artificial and pathological missense mutations on the structural ensembles of these IDPs using molecular dynamics simulations. We also emphasize the recent investigations on residual secondary structure formation in dynamic conformational ensembles of amyloid-β and α-synuclein, such as β-structure linked to the oligomerization and fibrillation mechanisms related to the pathologies of Alzheimer's and Parkinson's diseases. This information represents an important foundation for the successful and efficient drug design studies.
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Affiliation(s)
- Orkid Coskuner-Weber
- Türkisch-Deutsche Universität, Theoretical and Computational Biophysics Group, Molecular Biotechnology, Sahinkaya Caddesi, No. 86, Beykoz, Istanbul 34820, Turkey.
| | - Vladimir N Uversky
- Department of Molecular Medicine and USF Health Byrd Alzheimer's Research Institute, Morsani College of Medicine, University of South Florida, Tampa, FL 33612, USA.
- Laboratory of New Methods in Biology, Institute for Biological Instrumentation, Russian Academy of Sciences, 142290 Pushchino, Moscow Region, Russia.
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25
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Hasunuma N, Kawakami M, Hiramatsu H, Nakabayashi T. Preparation and photo-induced activities of water-soluble amyloid β-C60 complexes. RSC Adv 2018; 8:17847-17853. [PMID: 35542080 PMCID: PMC9080474 DOI: 10.1039/c8ra02789g] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2018] [Accepted: 05/04/2018] [Indexed: 01/06/2023] Open
Abstract
We have shown that fullerene (C60) becomes soluble in water by mixing fullerene and amyloid β peptide (Aβ40) whose fibril structures are considered to be associated with Alzheimer's disease. The water-solubility of fullerene arises from the generation of a nanosized complex between fullerene and the monomer species of Aβ40 (Aβ40-C60). The prepared Aβ40-C60 exhibits photo-induced activity with visible light to induce the inhibition of Aβ40 fibrillation and the cytotoxicity for cultured HeLa cells. The observed photo-induced phenomena result from the generation of singlet oxygen via photoexcitation, inducing oxidative damage to Aβ40 and HeLa cells. The oxidized Aβ40 following photoexcitation of Aβ40-C60 was confirmed by mass spectrometry. We have shown that fullerene (C60) becomes soluble in water by mixing fullerene and amyloid β peptide (Aβ40) whose fibril structures are considered to be associated with Alzheimer's disease.![]()
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Affiliation(s)
- Naoki Hasunuma
- Graduate School of Pharmaceutical Sciences
- Tohoku University
- Sendai 980-8578
- Japan
| | - Masahiro Kawakami
- Graduate School of Pharmaceutical Sciences
- Tohoku University
- Sendai 980-8578
- Japan
| | - Hirotsugu Hiramatsu
- Department of Applied Chemistry and Institute of Molecular Science
- National Chiao Tung University
- Hsinchu 30010
- Taiwan
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26
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Scesa G, Moyano AL, Bongarzone ER, Givogri MI. Port-to-port delivery: Mobilization of toxic sphingolipids via extracellular vesicles. J Neurosci Res 2017; 94:1333-40. [PMID: 27638615 DOI: 10.1002/jnr.23798] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2016] [Revised: 05/16/2016] [Accepted: 06/01/2016] [Indexed: 01/02/2023]
Abstract
The discovery that most cells produce extracellular vesicles (EVs) and release them in the extracellular milieu has spurred the idea that these membranous cargoes spread pathogenic mechanisms. In the brain, EVs may have multifold and important physiological functions, from deregulating synaptic activity to promoting demyelination to changes in microglial activity. The finding that small EVs (exosomes) contain α-synuclein and β-amyloid, among other pathogenic proteins, is an example of this notion, underscoring their potential role in the brains of patients with Parkinson's and Alzheimer's diseases. Given that they are membranous vesicles, we speculate that EVs also have an intrinsic capacity to incorporate sphingolipids. In conditions under which these lipids are elevated to toxic levels, such as in Krabbe's disease and metachromatic leukodystrophy, EVs may contribute to spread disease from sick to healthy cells. In this essay, we discuss a working hypothesis that brain cells in sphingolipidoses clear some of the accumulated lipid material to attempt restoring cell homeostasis via EV secretion. We hypothesize that secreted sphingolipid-loaded EVs shuttle pathogenic lipids to cells that are not intrinsically affected, contributing to establishing non-cell-autonomous defects. © 2016 Wiley Periodicals, Inc.
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Affiliation(s)
- Giuseppe Scesa
- Department of Anatomy and Cell Biology, College of Medicine. University of Illinois at Chicago, Chicago, Illinois
| | - Ana Lis Moyano
- Department of Anatomy and Cell Biology, College of Medicine. University of Illinois at Chicago, Chicago, Illinois
| | - Ernesto R Bongarzone
- Department of Anatomy and Cell Biology, College of Medicine. University of Illinois at Chicago, Chicago, Illinois
| | - Maria I Givogri
- Department of Anatomy and Cell Biology, College of Medicine. University of Illinois at Chicago, Chicago, Illinois.
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A Toxic Conformer of Aβ42 with a Turn at 22-23 is a Novel Therapeutic Target for Alzheimer's Disease. Sci Rep 2017; 7:11811. [PMID: 28924167 PMCID: PMC5603611 DOI: 10.1038/s41598-017-11671-6] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2017] [Accepted: 08/29/2017] [Indexed: 12/11/2022] Open
Abstract
Immunotherapy targeting Aβ42 is drawing attention as a possible therapeutic approach for Alzheimer’s disease (AD). Considering the significance of reported oligomerized Aβ42 species, selective targeting of the oligomer will increase the therapeutic efficacy. However, what kinds of oligomers are suitable targets for immunotherapy remains unclear. We previously identified a toxic conformer of Aβ42, which has a turn structure at 22–23 (“toxic turn”), among Aβ42 conformations. This toxic conformer of Aβ42 has been reported to show rapid oligomerization and to exhibit strong neurotoxicity and synaptotoxicity. We recently developed a monoclonal antibody against the toxic conformer (24B3), which demonstrated the increase of the toxic conformer in the cerebrospinal fluid of AD patients, indicating its accumulation in AD patients’ brains. In this study, we evaluated the therapeutic efficacy of 24B3 targeting the toxic conformer in AD model mice. The intraperitoneal administration of 24B3 for 3 months improved cognitive impairment and reduced the toxic conformer levels. Notably, this treatment did not reduce the number of senile plaques. Furthermore, the single intravenous administration of 24B3 suppressed the memory deficit in AD mice. These results suggest that the toxic conformer of Aβ42 with a turn at 22–23 represents one of the promising therapeutic targets.
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Oku Y, Murakami K, Irie K, Hoseki J, Sakai Y. Synthesized Aβ42 Caused Intracellular Oxidative Damage, Leading to Cell Death, via Lysosome Rupture. Cell Struct Funct 2017; 42:71-79. [PMID: 28413178 DOI: 10.1247/csf.17006] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022] Open
Abstract
Neuronal cellular accumulation of amyloid beta peptide (Aβ) has been implicated in the pathogenesis of Alzheimer's disease (AD). Intracellular accumulation of Aβ42, a toxic form of Aβ, was observed as an early event in AD patients. However, its contribution and the cellular mechanism of cell death remained unclear. We herein revealed the mechanism by which Aβ42 incorporated into cells leads to cell death by using chemically synthesized Aβ42 variants. The Aβ42 variant Aβ42 (E22P) which has an increased tendency to oligomerize, accumulated in lysosomes at an earlier stage than wild-type Aβ42, leading to higher ROS production and lysosomal membrane oxidation, and resulting in cell death. On the other hand, Aβ42 (E22V), which is incapable of oligomerization, did not accumulate in cells or affect the cell viability. Moreover, intracellular localization of EGFP-Galectin-3, a β-galactoside binding lectin, showed that accumulation of oligomerized Aβ42 in lysosomes caused lysosomal membrane permeabilization (LMP). Overexpression of lysosome-localized LAMP1-fused peroxiredoxin 1 and treatment with U18866A, an inhibitor of cholesterol export from lysosomes that causes an increase in lysosomal membrane stability, attenuated Aβ42-mediated LMP and cell death. Our findings show that lysosomal ROS generation by toxic conformer of Aβ led to cell death via LMP, and suggest that these events are potential targets for AD prevention.Key words: Amyloid-beta (Aβ), Cell death, Lysosome, Lysosomal membrane permeabilization, Reactive oxygen species (ROS).
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Affiliation(s)
- Yuki Oku
- Graduate School of Advanced Integrated Studies, Kyoto University
| | - Kazuma Murakami
- Division of Food Science and Biotechnology, Graduate School of Agriculture, Kyoto University.,Research Unit for Physiological Chemistry, Kyoto University
| | - Kazuhiro Irie
- Division of Food Science and Biotechnology, Graduate School of Agriculture, Kyoto University.,Research Unit for Physiological Chemistry, Kyoto University
| | - Jun Hoseki
- Research Unit for Physiological Chemistry, Kyoto University.,Division of Applied Life Sciences, Graduate School of Agriculture, Kyoto University
| | - Yasuyoshi Sakai
- Research Unit for Physiological Chemistry, Kyoto University.,Division of Applied Life Sciences, Graduate School of Agriculture, Kyoto University
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Abstract
Citrullination and deamidation, which are aging-related posttranslational modifications, increase the number of negative charges on amyloid β-protein (Aβ) at neutral pH. We investigated the effects of these modifications on the fibrillation properties of Aβ. The Arg5→Cit modification of Aβ1-40 did not affect the fibrillation rate, and brought β-sheet structures unlike that in the Aβ1-40 fibril. The Asn27→Asp modification of Aβ1-40 stopped the fibrillation and induced the formation of aggregates that involved an anti-parallel β-sheet. Aβ1-42 with the Arg5→Cit modification showed increased solubility in aqueous media, and its fibril formation became slower than that of Aβ1-42. The modification did not change the parallel β-sheet structure of the fibrils. Aβ1-42 with the Asn27→Asp modification partially formed fibrils that involved the parallel β-sheet structure. Using the thioflavin T (ThT) assay, an increased fraction of the soluble oligomer of each Aβ analog was transiently detected during fibrillation. An increase in the number of negative charges at basic pH affected the aggregation properties of Aβ in a manner different from that with the modifications, suggesting that change in properties of the posttanslationally modified residues rather than the number of charges in the peptide was important.
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Affiliation(s)
- Dai Osaki
- a Graduate School of Pharmaceutical Sciences, Tohoku University , Sendai , Japan
| | - Hirotsugu Hiramatsu
- a Graduate School of Pharmaceutical Sciences, Tohoku University , Sendai , Japan
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Yagi-Utsumi M, Dobson CM. Conformational Effects of the A21G Flemish Mutation on the Aggregation of Amyloid β Peptide. Biol Pharm Bull 2016; 38:1668-72. [PMID: 26424029 DOI: 10.1248/bpb.b15-00466] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Among the various hereditary mutants of amyloid β (Aβ) in familial Alzheimer's disease (AD), the A21G Flemish-type mutant has unique properties showing a low aggregation propensity but progressive deposition in vascular walls. Moreover, in contrast to other familial AD cases that show extensive Aβ1-42 deposition in the brain, patients with Flemish AD predominantly exhibit the deposition of the Aβ1-40 isoform. Here we report the structural characterization of the Flemish-type mutant (A21G) in comparison with the wild-type Aβ1-40 peptide to examine the possible effects of the A21G mutation on the conformation of the Aβ1-40 isoform. The kinetic analysis of the aggregation of the peptides monitored by thioflavin T fluorescence measurement indicates that the mutation precludes the initial nucleation process of amyloid fibril formation by Aβ1-40. Spectroscopic data indicate that the Flemish-type mutant bound to aqueous micelles composed of lyso-GM1, in which the mobile N-terminal segment is tethered through the C-terminal helical segment, has reduced α-helical structure compared to the wild-type peptide. Our findings suggest that the mutational perturbation to the membrane binding properties is coupled with the changes in nucleation behavior of Aβ during its fibril formation.
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Tryptophan-2,3-dioxygenase (TDO) inhibition ameliorates neurodegeneration by modulation of kynurenine pathway metabolites. Proc Natl Acad Sci U S A 2016; 113:5435-40. [PMID: 27114543 DOI: 10.1073/pnas.1604453113] [Citation(s) in RCA: 105] [Impact Index Per Article: 13.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Metabolites of the kynurenine pathway (KP) of tryptophan (TRP) degradation have been closely linked to the pathogenesis of several neurodegenerative disorders. Recent work has highlighted the therapeutic potential of inhibiting two critical regulatory enzymes in this pathway-kynurenine-3-monooxygenase (KMO) and tryptophan-2,3-dioxygenase (TDO). Much evidence indicates that the efficacy of KMO inhibition arises from normalizing an imbalance between neurotoxic [3-hydroxykynurenine (3-HK); quinolinic acid (QUIN)] and neuroprotective [kynurenic acid (KYNA)] KP metabolites. However, it is not clear if TDO inhibition is protective via a similar mechanism or if this is instead due to increased levels of TRP-the substrate of TDO. Here, we find that increased levels of KYNA relative to 3-HK are likely central to the protection conferred by TDO inhibition in a fruit fly model of Huntington's disease and that TRP treatment strongly reduces neurodegeneration by shifting KP flux toward KYNA synthesis. In fly models of Alzheimer's and Parkinson's disease, we provide genetic evidence that inhibition of TDO or KMO improves locomotor performance and ameliorates shortened life span, as well as reducing neurodegeneration in Alzheimer's model flies. Critically, we find that treatment with a chemical TDO inhibitor is robustly protective in these models. Consequently, our work strongly supports targeting of the KP as a potential treatment strategy for several major neurodegenerative disorders and suggests that alterations in the levels of neuroactive KP metabolites could underlie several therapeutic benefits.
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Liang CT, Huang HB, Wang CC, Chen YR, Chang CF, Shiao MS, Chen YC, Lin TH. L17A/F19A Substitutions Augment the α-Helicity of β-Amyloid Peptide Discordant Segment. PLoS One 2016; 11:e0154327. [PMID: 27104649 PMCID: PMC4841593 DOI: 10.1371/journal.pone.0154327] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2016] [Accepted: 04/12/2016] [Indexed: 11/18/2022] Open
Abstract
β-amyloid peptide (Aβ) aggregation has been thought to be associated with the pathogenesis of Alzheimer’s disease. Recently, we showed that L17A/F19A substitutions may increase the structural stability of wild-type and Arctic-type Aβ40 and decrease the rates of structural conversion and fibril formation. However, the underlying mechanism for the increase of structural stability as a result of the alanine substitutions remained elusive. In this study, we apply nuclear magnetic resonance and circular dichroism spectroscopies to characterize the Aβ40 structure, demonstrating that L17A/F19A substitutions can augment the α-helicity of the residues located in the α/β-discordant segment (resides 15 to 23) of both wild-type and Arctic-type Aβ40. These results provide a structural basis to link the α-helicity of the α/β-discordant segment with the conformational conversion propensity of Aβ.
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Affiliation(s)
- Chu-Ting Liang
- Department of Life Sciences and Institute of Genome Sciences, National Yang-Ming University, Taipei, Taiwan, R.O.C
- Basic Research Division, Medical Research Department, Taipei Veterans General Hospital, Taipei, Taiwan, R.O.C
| | - Hsien-Bin Huang
- Department of Life Science and the Institute of Molecular Biology, National Chung Cheng University, Chiayi, Taiwan, R.O.C
| | - Chih-Ching Wang
- Structural Biology Program, National Yang-Ming University, Taipei, Taiwan, R.O.C
- Institute of Biochemistry & Molecular Biology, National Yang-Ming University, Taipei, Taiwan, R.O.C
| | - Yi-Ru Chen
- Structural Biology Program, National Yang-Ming University, Taipei, Taiwan, R.O.C
- Department and Institute of Pharmacology, National Yang-Ming University, Taipei, Taiwan, R.O.C
| | - Chi-Fon Chang
- Genomics Research Center, Academia Sinica, Taipei, Taiwan, R.O.C
| | - Ming-Shi Shiao
- Department of Biomedical Sciences, Chang Gung University, Taoyuan, Taiwan, R.O.C
| | - Yi-Cheng Chen
- Department of Medicine, Mackay Medical College, Taipei, Taiwan, R.O.C
- * E-mail: (YCC); (THL)
| | - Ta-Hsien Lin
- Department of Life Sciences and Institute of Genome Sciences, National Yang-Ming University, Taipei, Taiwan, R.O.C
- Basic Research Division, Medical Research Department, Taipei Veterans General Hospital, Taipei, Taiwan, R.O.C
- Structural Biology Program, National Yang-Ming University, Taipei, Taiwan, R.O.C
- Institute of Biochemistry & Molecular Biology, National Yang-Ming University, Taipei, Taiwan, R.O.C
- * E-mail: (YCC); (THL)
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34
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Hunter S, Martin S, Brayne C. The APP Proteolytic System and Its Interactions with Dynamic Networks in Alzheimer's Disease. Methods Mol Biol 2016; 1303:71-99. [PMID: 26235060 DOI: 10.1007/978-1-4939-2627-5_3] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
Diseases of aging are often complex and multifactorial, involving many genetic and life course modifiers. Systems biology is becoming an essential tool to investigate disease initiation and disease progression. Alzheimer's disease (AD) can be used as a case study to investigate the application of systems biology to complex disease. Here we describe approaches to capturing biological data, representing data in terms of networks and interpreting their meaning in relation to the human population. We highlight issues that remain to be addressed both in terms of modeling disease progression and in relating findings to the current understanding of human disease.
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Affiliation(s)
- Sally Hunter
- Department of Public Health and Primary Care, Institute of Public Health, University of Cambridge School of Clinical Medicine, Forvie Site, Cambridge Biomedical Campus, Box 113, Cambridge, CB2 0SP, UK,
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35
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Lee CC, Julian MC, Tiller KE, Meng F, DuConge SE, Akter R, Raleigh DP, Tessier PM. Design and Optimization of Anti-amyloid Domain Antibodies Specific for β-Amyloid and Islet Amyloid Polypeptide. J Biol Chem 2015; 291:2858-73. [PMID: 26601942 DOI: 10.1074/jbc.m115.682336] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2015] [Indexed: 12/25/2022] Open
Abstract
Antibodies with conformational specificity are important for detecting and interfering with polypeptide aggregation linked to several human disorders. We are developing a motif-grafting approach for designing lead antibody candidates specific for amyloid-forming polypeptides such as the Alzheimer peptide (Aβ). This approach involves grafting amyloidogenic peptide segments into the complementarity-determining regions (CDRs) of single-domain (VH) antibodies. Here we have investigated the impact of polar mutations inserted at the edges of a large hydrophobic Aβ42 peptide segment (Aβ residues 17-42) in CDR3 on the solubility and conformational specificity of the corresponding VH domains. We find that VH expression and solubility are strongly enhanced by introducing multiple negatively charged or asparagine residues at the edges of CDR3, whereas other polar mutations are less effective (glutamine and serine) or ineffective (threonine, lysine, and arginine). Moreover, Aβ VH domains with negatively charged CDR3 mutations show significant preference for recognizing Aβ fibrils relative to Aβ monomers, whereas the same VH domains with other polar CDR3 mutations recognize both Aβ conformers. We observe similar behavior for a VH domain grafted with a large hydrophobic peptide from islet amyloid polypeptide (residues 8-37) that contains negatively charged mutations at the edges of CDR3. These findings highlight the sensitivity of antibody binding and solubility to residues at the edges of CDRs, and provide guidelines for designing other grafted antibody fragments with hydrophobic binding loops.
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Affiliation(s)
- Christine C Lee
- From the Center for Biotechnology and Interdisciplinary Studies, Isermann Department of Chemical and Biological Engineering, Rensselaer Polytechnic Institute, Troy, New York 12180 and
| | - Mark C Julian
- From the Center for Biotechnology and Interdisciplinary Studies, Isermann Department of Chemical and Biological Engineering, Rensselaer Polytechnic Institute, Troy, New York 12180 and
| | - Kathryn E Tiller
- From the Center for Biotechnology and Interdisciplinary Studies, Isermann Department of Chemical and Biological Engineering, Rensselaer Polytechnic Institute, Troy, New York 12180 and
| | - Fanling Meng
- From the Center for Biotechnology and Interdisciplinary Studies, Isermann Department of Chemical and Biological Engineering, Rensselaer Polytechnic Institute, Troy, New York 12180 and
| | - Sarah E DuConge
- From the Center for Biotechnology and Interdisciplinary Studies, Isermann Department of Chemical and Biological Engineering, Rensselaer Polytechnic Institute, Troy, New York 12180 and
| | - Rehana Akter
- the Department of Chemistry, Stony Brook University, Stony Brook, New York 11794
| | - Daniel P Raleigh
- the Department of Chemistry, Stony Brook University, Stony Brook, New York 11794
| | - Peter M Tessier
- From the Center for Biotechnology and Interdisciplinary Studies, Isermann Department of Chemical and Biological Engineering, Rensselaer Polytechnic Institute, Troy, New York 12180 and
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36
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Aβ42-oligomer Interacting Peptide (AIP) neutralizes toxic amyloid-β42 species and protects synaptic structure and function. Sci Rep 2015; 5:15410. [PMID: 26510576 PMCID: PMC4625140 DOI: 10.1038/srep15410] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2015] [Accepted: 09/22/2015] [Indexed: 12/21/2022] Open
Abstract
The amyloid-β42 (Aβ42) peptide is believed to be the main culprit in the pathogenesis of Alzheimer disease (AD), impairing synaptic function and initiating neuronal degeneration. Soluble Aβ42 oligomers are highly toxic and contribute to progressive neuronal dysfunction, loss of synaptic spine density, and affect long-term potentiation (LTP). We have characterized a short, L-amino acid Aβ-oligomer Interacting Peptide (AIP) that targets a relatively well-defined population of low-n Aβ42 oligomers, rather than simply inhibiting the aggregation of Aβ monomers into oligomers. Our data show that AIP diminishes the loss of Aβ42-induced synaptic spine density and rescues LTP in organotypic hippocampal slice cultures. Notably, the AIP enantiomer (comprised of D-amino acids) attenuated the rough-eye phenotype in a transgenic Aβ42 fly model and significantly improved the function of photoreceptors of these flies in electroretinography tests. Overall, our results indicate that specifically “trapping” low-n oligomers provides a novel strategy for toxic Aβ42-oligomer recognition and removal.
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37
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Hubin E, Deroo S, Schierle GK, Kaminski C, Serpell L, Subramaniam V, van Nuland N, Broersen K, Raussens V, Sarroukh R. Two distinct β-sheet structures in Italian-mutant amyloid-beta fibrils: a potential link to different clinical phenotypes. Cell Mol Life Sci 2015; 72:4899-913. [PMID: 26190022 PMCID: PMC4648968 DOI: 10.1007/s00018-015-1983-2] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2015] [Revised: 06/06/2015] [Accepted: 07/02/2015] [Indexed: 12/22/2022]
Abstract
Most Alzheimer’s disease (AD) cases are late-onset and characterized by the aggregation and deposition of the amyloid-beta (Aβ) peptide in extracellular plaques in the brain. However, a few rare and hereditary Aβ mutations, such as the Italian Glu22-to-Lys (E22K) mutation, guarantee the development of early-onset familial AD. This type of AD is associated with a younger age at disease onset, increased β-amyloid accumulation, and Aβ deposition in cerebral blood vessel walls, giving rise to cerebral amyloid angiopathy (CAA). It remains largely unknown how the Italian mutation results in the clinical phenotype that is characteristic of CAA. We therefore investigated how this single point mutation may affect the aggregation of Aβ1–42 in vitro and structurally characterized the resulting fibrils using a biophysical approach. This paper reports that wild-type and Italian-mutant Aβ both form fibrils characterized by the cross-β architecture, but with distinct β-sheet organizations, resulting in differences in thioflavin T fluorescence and solvent accessibility. E22K Aβ1–42 oligomers and fibrils both display an antiparallel β-sheet structure, in comparison with the parallel β-sheet structure of wild-type fibrils, characteristic of most amyloid fibrils described in the literature. Moreover, we demonstrate structural plasticity for Italian-mutant Aβ fibrils in a pH-dependent manner, in terms of their underlying β-sheet arrangement. These findings are of interest in the ongoing debate that (1) antiparallel β-sheet structure might represent a signature for toxicity, which could explain the higher toxicity reported for the Italian mutant, and that (2) fibril polymorphism might underlie differences in disease pathology and clinical manifestation.
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Affiliation(s)
- Ellen Hubin
- Nanobiophysics Group, Faculty of Science and Technology, MIRA Institute for Biomedical Technology and Technical Medicine, University of Twente, 7500 AE, Enschede, The Netherlands.,Structural Biology Brussels, Department of Biotechnology (DBIT), Vrije Universiteit Brussel (VUB), Pleinlaan 2, 1050, Brussels, Belgium.,Structural Biology Research Center, VIB, Pleinlaan 2, 1050, Brussels, Belgium
| | - Stéphanie Deroo
- Laboratory of Structure and Function of Biological Membrane, Faculté des Sciences, Center for Structural Biology and Bioinformatics, Université Libre de Bruxelles (ULB), Campus de la Plaine CP 206/02, Boulevard du Triomphe, 1050, Brussels, Belgium
| | - Gabriele Kaminksi Schierle
- Department of Chemical Engineering and Biotechnology, University of Cambridge, New Museums Site, Pembroke Street, Cambridge, CB2 3RA, UK
| | - Clemens Kaminski
- Department of Chemical Engineering and Biotechnology, University of Cambridge, New Museums Site, Pembroke Street, Cambridge, CB2 3RA, UK
| | - Louise Serpell
- School of Life Sciences, University of Sussex, Falmer, East Sussex, BN1 9QG, UK
| | - Vinod Subramaniam
- Nanobiophysics Group, Faculty of Science and Technology, MIRA Institute for Biomedical Technology and Technical Medicine, University of Twente, 7500 AE, Enschede, The Netherlands.,FOM Institute AMOLF, Science Park 104, 1098 XG, Amsterdam, The Netherlands
| | - Nico van Nuland
- Structural Biology Brussels, Department of Biotechnology (DBIT), Vrije Universiteit Brussel (VUB), Pleinlaan 2, 1050, Brussels, Belgium.,Structural Biology Research Center, VIB, Pleinlaan 2, 1050, Brussels, Belgium
| | - Kerensa Broersen
- Nanobiophysics Group, Faculty of Science and Technology, MIRA Institute for Biomedical Technology and Technical Medicine, University of Twente, 7500 AE, Enschede, The Netherlands.
| | - Vincent Raussens
- Laboratory of Structure and Function of Biological Membrane, Faculté des Sciences, Center for Structural Biology and Bioinformatics, Université Libre de Bruxelles (ULB), Campus de la Plaine CP 206/02, Boulevard du Triomphe, 1050, Brussels, Belgium
| | - Rabia Sarroukh
- Laboratory of Structure and Function of Biological Membrane, Faculté des Sciences, Center for Structural Biology and Bioinformatics, Université Libre de Bruxelles (ULB), Campus de la Plaine CP 206/02, Boulevard du Triomphe, 1050, Brussels, Belgium.
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38
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Lo CJ, Wang CC, Huang HB, Chang CF, Shiao MS, Chen YC, Lin TH. The Arctic mutation accelerates Aβ aggregation in SDS through reducing the helical propensity of residues 15-25. Amyloid 2015; 22:8-18. [PMID: 25376379 DOI: 10.3109/13506129.2014.980943] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
Mutations within the β-amyloid peptide (Aβ) sequence that cause early onset familial Alzheimer's disease (FAD) have been shown to promote Aβ aggregation. How these FAD-related mutants increase the aggregative ability of Aβ is not fully understood. Here, we characterized the effect of the Arctic variant (E22G) on the conformational stability of Aβ using various forms of spectroscopy and kinetic analyses, including nuclear magnetic resonance (NMR), circular dichroism (CD) spectroscopy, Fourier-transform infrared (FT-IR) spectroscopy and transmission electron microscopy (TEM). The E22G mutation in the Arctic variant reduced the α-helical propensity and conformational stability of Aβ on residues 15-25. This mutation also caused an increase in both α-helix-to-β-strand conversion and fibril nucleation rates. Our results suggest that the α-helical propensity of residues 15-25 may play a determinant role in the aggregative ability of Aβ. This may provide a structural basis for understanding the molecular mechanism of Aβ aggregation.
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Affiliation(s)
- Chi-Jen Lo
- Institute of Biochemistry & Molecular Biology, National Yang-Ming University , Taipei, Taiwan , ROC
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39
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Extracellular vesicles--Their role in the packaging and spread of misfolded proteins associated with neurodegenerative diseases. Semin Cell Dev Biol 2015; 40:89-96. [PMID: 25704308 DOI: 10.1016/j.semcdb.2015.02.007] [Citation(s) in RCA: 162] [Impact Index Per Article: 18.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2014] [Revised: 02/13/2015] [Accepted: 02/15/2015] [Indexed: 12/13/2022]
Abstract
Many cell types, including neurons, are known to release small membranous vesicles known as exosomes. In addition to their protein content these vesicles have recently been shown to contain messenger RNA (mRNA) and micro RNA (miRNA) species. Roles for these vesicles include cell-cell signalling, removal of unwanted proteins, and transfer of pathogens (including prion-like misfolded proteins) between cells, such as infectious prions. Prions are the infectious particles that are responsible for transmissible neurodegenerative diseases such as Creutzfeldt-Jakob disease (CJD) of humans or bovine spongiform encephalopathy (BSE) of cattle. Exosomes are also involved in processing the amyloid precursor protein (APP), which is associated with Alzheimer's disease (AD). As exosomes can be isolated from circulating fluids such as serum, urine, and cerebrospinal fluid (CSF), they provide a potential source of biomarkers for neurological conditions. Here, we review the roles these vesicles play in neurodegenerative disease and highlight their potential in diagnosing these disorders through analysis of their RNA content.
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40
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Solé M, Miñano-Molina AJ, Unzeta M. A cross-talk between Aβ and endothelial SSAO/VAP-1 accelerates vascular damage and Aβ aggregation related to CAA-AD. Neurobiol Aging 2015; 36:762-75. [DOI: 10.1016/j.neurobiolaging.2014.09.030] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2014] [Revised: 09/18/2014] [Accepted: 09/29/2014] [Indexed: 02/07/2023]
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41
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Ringman JM, Goate A, Masters CL, Cairns NJ, Danek A, Graff-Radford N, Ghetti B, Morris JC. Genetic heterogeneity in Alzheimer disease and implications for treatment strategies. Curr Neurol Neurosci Rep 2014; 14:499. [PMID: 25217249 PMCID: PMC4162987 DOI: 10.1007/s11910-014-0499-8] [Citation(s) in RCA: 59] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Since the original publication describing the illness in 1907, the genetic understanding of Alzheimer's disease (AD) has advanced such that it is now clear that it is a genetically heterogeneous condition, the subtypes of which may not uniformly respond to a given intervention. It is therefore critical to characterize the clinical and preclinical stages of AD subtypes, including the rare autosomal dominant forms caused by known mutations in the PSEN1, APP, and PSEN2 genes that are being studied in the Dominantly Inherited Alzheimer Network study and its associated secondary prevention trial. Similar efforts are occurring in an extended Colombian family with a PSEN1 mutation, in APOE ε4 homozygotes, and in Down syndrome. Despite commonalities in the mechanisms producing the AD phenotype, there are also differences that reflect specific genetic origins. Treatment modalities should be chosen and trials designed with these differences in mind. Ideally, the varying pathological cascades involved in the different subtypes of AD should be defined so that both areas of overlap and of distinct differences can be taken into account. At the very least, clinical trials should determine the influence of known genetic factors in post hoc analyses.
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Affiliation(s)
- John M Ringman
- Mary S. Easton Center for Alzheimer's Disease Research, David Geffen School of Medicine at University of California, Los Angeles, 10911 Weyburn Ave., #200, Los Angeles, 90095-7226, CA, USA,
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Structure–Activity Relationship for (+)-Taxifolin Isolated from Silymarin as an Inhibitor of Amyloid β Aggregation. Biosci Biotechnol Biochem 2014; 77:1100-3. [DOI: 10.1271/bbb.120925] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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Verification of the Intermolecular Parallel β-Sheet in E22K-Aβ42 Aggregates by Solid-State NMR Using Rotational Resonance: Implications for the Supramolecular Arrangement of the Toxic Conformer of Aβ42. Biosci Biotechnol Biochem 2014; 72:2170-5. [DOI: 10.1271/bbb.80250] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
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44
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Silymarin Attenuated the Amyloid β Plaque Burden and Improved Behavioral Abnormalities in an Alzheimer’s Disease Mouse Model. Biosci Biotechnol Biochem 2014; 74:2299-306. [DOI: 10.1271/bbb.100524] [Citation(s) in RCA: 52] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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45
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Hunter S, Brayne C. Integrating the molecular and the population approaches to dementia research to help guide the future development of appropriate therapeutics. Biochem Pharmacol 2014; 88:652-60. [DOI: 10.1016/j.bcp.2013.12.015] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2013] [Revised: 12/18/2013] [Accepted: 12/18/2013] [Indexed: 12/13/2022]
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46
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Smith MD, Cruz L. Changes to the Structure and Dynamics in Mutations of Aβ21–30 Caused by Ions in Solution. J Phys Chem B 2013; 117:14907-15. [DOI: 10.1021/jp408579v] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Micholas Dean Smith
- Department
of Physics, Drexel University, 3141 Chestnut Street, Philadelphia 19104, Pennsylvania, United States
| | - Luis Cruz
- Department
of Physics, Drexel University, 3141 Chestnut Street, Philadelphia 19104, Pennsylvania, United States
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Bossis F, Palese LL. Amyloid beta(1-42) in aqueous environments: effects of ionic strength and E22Q (Dutch) mutation. BIOCHIMICA ET BIOPHYSICA ACTA-PROTEINS AND PROTEOMICS 2013; 1834:2486-93. [PMID: 24016775 DOI: 10.1016/j.bbapap.2013.08.010] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/18/2013] [Revised: 08/26/2013] [Accepted: 08/29/2013] [Indexed: 01/15/2023]
Abstract
Development of extracellular plaques characteristic of Alzheimer's disease is related to aggregation of amyloid peptides. The Aβ-42 peptide is the most aggregation prone species, and some missense mutant forms increase this aggregation ability. Due to its poor solubility as monomer in aqueous solutions, Aβ-42 conformational transitions in water have been largely investigated by molecular dynamics. Here we report an all-atom molecular dynamics analysis of the Aβ-42 peptide in aqueous environment using as starting conformation a structure obtained in an isotropic, low-polarity medium, representing a plausible model for the membrane-bound species. While previous studies commonly show that Aβ-42 is largely unstructured in aqueous solution, here we report that this peptide can adopt partially folded structures. Importance of ionic strength has been also investigated, showing that at physiological ionic strength condition a loop stabilizing electrostatic interaction involving Lys28 builds up. In addition, besides stable α-helix structures, we observe the appearance of 310 helix, similar to what was reported experimentally for the Aβ-40 species. The effect of E22Q (Dutch) mutation in high ionic strength condition has been explored. We show that this mutation has a dramatic impact on the Aβ-42 structure. Instead of a partially folded, but extended, conformation obtained with the wild type, the E22Q assumes a two-helix collapsed one due to the clustering of hydrophobic residues.
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48
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Pulsed hydrogen-deuterium exchange mass spectrometry probes conformational changes in amyloid beta (Aβ) peptide aggregation. Proc Natl Acad Sci U S A 2013; 110:14604-9. [PMID: 23959898 DOI: 10.1073/pnas.1309175110] [Citation(s) in RCA: 94] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Probing the conformational changes of amyloid beta (Aβ) peptide aggregation is challenging owing to the vast heterogeneity of the resulting soluble aggregates. To investigate the formation of these aggregates in solution, we designed an MS-based biophysical approach and applied it to the formation of soluble aggregates of the Aβ42 peptide, the proposed causative agent in Alzheimer's disease. The approach incorporates pulsed hydrogen-deuterium exchange coupled with MS analysis. The combined approach provides evidence for a self-catalyzed aggregation with a lag phase, as observed previously by fluorescence methods. Unlike those approaches, pulsed hydrogen-deuterium exchange does not require modified Aβ42 (e.g., labeling with a fluorophore). Furthermore, the approach reveals that the center region of Aβ42 is first to aggregate, followed by the C and N termini. We also found that the lag phase in the aggregation of soluble species is affected by temperature and Cu(2+) ions. This MS approach has sufficient structural resolution to allow interrogation of Aβ aggregation in physiologically relevant environments. This platform should be generally useful for investigating the aggregation of other amyloid-forming proteins and neurotoxic soluble peptide aggregates.
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Sato M, Murakami K, Uno M, Nakagawa Y, Katayama S, Akagi KI, Masuda Y, Takegoshi K, Irie K. Site-specific inhibitory mechanism for amyloid β42 aggregation by catechol-type flavonoids targeting the Lys residues. J Biol Chem 2013; 288:23212-24. [PMID: 23792961 PMCID: PMC3743493 DOI: 10.1074/jbc.m113.464222] [Citation(s) in RCA: 177] [Impact Index Per Article: 16.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2013] [Revised: 06/15/2013] [Indexed: 11/06/2022] Open
Abstract
The aggregation of the 42-residue amyloid β-protein (Aβ42) is involved in the pathogenesis of Alzheimer disease (AD). Numerous flavonoids exhibit inhibitory activity against Aβ42 aggregation, but their mechanism remains unclear in the molecular level. Here we propose the site-specific inhibitory mechanism of (+)-taxifolin, a catechol-type flavonoid, whose 3',4'-dihydroxyl groups of the B-ring plays a critical role. Addition of sodium periodate, an oxidant, strengthened suppression of Aβ42 aggregation by (+)-taxifolin, whereas no inhibition was observed under anaerobic conditions, suggesting the inhibition to be associated with the oxidation to form o-quinone. Because formation of the Aβ42-taxifolin adduct was suggested by mass spectrometry, Aβ42 mutants substituted at Arg(5), Lys(16), and/or Lys(28) with norleucine (Nle) were prepared to identify the residues involved in the conjugate formation. (+)-Taxifolin did not suppress the aggregation of Aβ42 mutants at Lys(16) and/or Lys(28) except for the mutant at Arg(5). In addition, the aggregation of Aβ42 was inhibited by other catechol-type flavonoids, whereas that of K16Nle-Aβ42 was not. In contrast, some non-catechol-type flavonoids suppressed the aggregation of K16Nle-Aβ42 as well as Aβ42. Furthermore, interaction of (+)-taxifolin with the β-sheet region in Aβ42 was not observed using solid-state NMR unlike curcumin of the non-catechol-type. These results demonstrate that catechol-type flavonoids could specifically suppress Aβ42 aggregation by targeting Lys residues. Although the anti-AD activity of flavonoids has been ascribed to their antioxidative activity, the mechanism that the o-quinone reacts with Lys residues of Aβ42 might be more intrinsic. The Lys residues could be targets for Alzheimer disease therapy.
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Affiliation(s)
- Mizuho Sato
- From the Division of Food Science and Biotechnology, Graduate School of Agriculture, and
| | - Kazuma Murakami
- From the Division of Food Science and Biotechnology, Graduate School of Agriculture, and
| | - Mayumi Uno
- From the Division of Food Science and Biotechnology, Graduate School of Agriculture, and
| | - Yu Nakagawa
- From the Division of Food Science and Biotechnology, Graduate School of Agriculture, and
- the Synthetic Cellular Chemistry Laboratory, RIKEN Advanced Science Institute, Saitama 351-0198
| | - Sumie Katayama
- the National Institute of Biomedical Innovation, Osaka 567-0085, and
| | - Ken-ichi Akagi
- the National Institute of Biomedical Innovation, Osaka 567-0085, and
| | - Yuichi Masuda
- the Department of Chemistry, Graduate School of Science, Kyoto University, Kyoto 606-8502
- the Graduate School of Pharmaceutical Sciences, Tohoku University, Sendai 980-8578, Japan
| | - Kiyonori Takegoshi
- the Department of Chemistry, Graduate School of Science, Kyoto University, Kyoto 606-8502
| | - Kazuhiro Irie
- From the Division of Food Science and Biotechnology, Graduate School of Agriculture, and
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Shahnawaz M, Sharoar MG, Shin SY, Park IS. Wild-type, Flemish, and Dutch amyloid-β
exhibit different cytotoxicities depending on Aβ
40 to Aβ
42 interaction time and concentration ratio. J Pept Sci 2013; 19:545-53. [DOI: 10.1002/psc.2531] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2013] [Revised: 05/03/2013] [Accepted: 05/26/2013] [Indexed: 11/10/2022]
Affiliation(s)
- Md. Shahnawaz
- Department of Bio-materials Engineering; College of Medicine, Chosun University; Gwangju 501-759 Korea
- Medical School; The University of Texas Health Science Center at Houston; 6431 Fannin St Houston TX 77030 USA
| | - Md. Golam Sharoar
- Department of Bio-materials Engineering; College of Medicine, Chosun University; Gwangju 501-759 Korea
- Department of Genetic Engineering and Biotechnology; University of Rajshahi; Rajshahi 6205 Bangladesh
| | - Song Yub Shin
- Department of Bio-materials Engineering; College of Medicine, Chosun University; Gwangju 501-759 Korea
- Department of Cell and Molecular Biology; College of Medicine, Chosun University; Gwangju 501-759 Korea
| | - Il-Seon Park
- Department of Bio-materials Engineering; College of Medicine, Chosun University; Gwangju 501-759 Korea
- Department of Cell and Molecular Biology; College of Medicine, Chosun University; Gwangju 501-759 Korea
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