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Candelise N, Caissutti D, Zenuni H, Nesci V, Scaricamazza S, Salvatori I, Spinello Z, Mattei V, Garofalo T, Ferri A, Valle C, Misasi R. Different Chronic Stress Paradigms Converge on Endogenous TDP43 Cleavage and Aggregation. Mol Neurobiol 2023; 60:6346-6361. [PMID: 37450246 PMCID: PMC10533643 DOI: 10.1007/s12035-023-03455-z] [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: 02/01/2023] [Accepted: 06/17/2023] [Indexed: 07/18/2023]
Abstract
The TAR-DNA binding protein (TDP43) is a nuclear protein whose cytoplasmic inclusions are hallmarks of Amyotrophic Lateral Sclerosis (ALS). Acute stress in cells causes TDP43 mobilization to the cytoplasm and its aggregation through different routes. Although acute stress elicits a strong phenotype, is far from recapitulating the years-long aggregation process. We applied different chronic stress protocols and described TDP43 aggregation in a human neuroblastoma cell line by combining solubility assays, thioflavin-based microscopy and flow cytometry. This approach allowed us to detect, for the first time to our knowledge in vitro, the formation of 25 kDa C-terminal fragment of TDP43, a pathogenic hallmark of ALS. Our results indicate that chronic stress, compared to the more common acute stress paradigm, better recapitulates the cell biology of TDP43 proteinopathies. Moreover, we optimized a protocol for the detection of bona fide prions in living cells, suggesting that TDP43 may form amyloids as a stress response.
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Affiliation(s)
- Niccolò Candelise
- Department of Experimental Medicine, University La Sapienza, 00185, Rome, Italy
- IRCCS Fondazione Santa Lucia, 00179, Rome, Italy
| | - Daniela Caissutti
- Department of Experimental Medicine, University La Sapienza, 00185, Rome, Italy
| | - Henri Zenuni
- Department of Systems Medicine, Tor Vergata" University of Rome, 00133, Rome, Italy
| | - Valentina Nesci
- IRCCS Fondazione Santa Lucia, 00179, Rome, Italy
- Department of Systems Medicine, Tor Vergata" University of Rome, 00133, Rome, Italy
| | | | - Illari Salvatori
- Department of Experimental Medicine, University La Sapienza, 00185, Rome, Italy
- IRCCS Fondazione Santa Lucia, 00179, Rome, Italy
| | - Zaira Spinello
- Department of Experimental Medicine, University La Sapienza, 00185, Rome, Italy
| | - Vincenzo Mattei
- Biomedicine and Advanced Technologies Rieti Center, Sabina Universitas, 02100, Rieti, Italy
| | - Tina Garofalo
- Department of Experimental Medicine, University La Sapienza, 00185, Rome, Italy
| | - Alberto Ferri
- IRCCS Fondazione Santa Lucia, 00179, Rome, Italy
- Institute of Translational Pharmacology (IFT), Consiglio Nazionale Delle Ricerche (CNR), 00185, Rome, Italy
| | - Cristiana Valle
- IRCCS Fondazione Santa Lucia, 00179, Rome, Italy.
- Institute of Translational Pharmacology (IFT), Consiglio Nazionale Delle Ricerche (CNR), 00185, Rome, Italy.
| | - Roberta Misasi
- Department of Experimental Medicine, University La Sapienza, 00185, Rome, Italy.
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Opalek M, Tutaj H, Pirog A, Smug BJ, Rutkowska J, Wloch-Salamon D. A Systematic Review on Quiescent State Research Approaches in S. cerevisiae. Cells 2023; 12:1608. [PMID: 37371078 DOI: 10.3390/cells12121608] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2023] [Revised: 06/02/2023] [Accepted: 06/09/2023] [Indexed: 06/29/2023] Open
Abstract
Quiescence, the temporary and reversible arrest of cell growth, is a fundamental biological process. However, the lack of standardization in terms of reporting the experimental details of quiescent cells and populations can cause confusion and hinder knowledge transfer. We employ the systematic review methodology to comprehensively analyze the diversity of approaches used to study the quiescent state, focusing on all published research addressing the budding yeast Saccharomyces cerevisiae. We group research articles into those that consider all cells comprising the stationary-phase (SP) population as quiescent and those that recognize heterogeneity within the SP by distinguishing phenotypically distinct subpopulations. Furthermore, we investigate the chronological age of the quiescent populations under study and the methods used to induce the quiescent state, such as gradual starvation or abrupt environmental change. We also assess whether the strains used in research are prototrophic or auxotrophic. By combining the above features, we identify 48 possible experimental setups that can be used to study quiescence, which can be misleading when drawing general conclusions. We therefore summarize our review by proposing guidelines and recommendations pertaining to the information included in research articles. We believe that more rigorous reporting on the features of quiescent populations will facilitate knowledge transfer within and between disciplines, thereby stimulating valuable scientific discussion.
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Affiliation(s)
- Monika Opalek
- Institute of Environmental Sciences, Faculty of Biology, Jagiellonian University, 30-387 Krakow, Poland
| | - Hanna Tutaj
- Institute of Environmental Sciences, Faculty of Biology, Jagiellonian University, 30-387 Krakow, Poland
| | - Adrian Pirog
- Institute of Environmental Sciences, Faculty of Biology, Jagiellonian University, 30-387 Krakow, Poland
| | - Bogna J Smug
- Malopolska Centre of Biotechnology, Jagiellonian University, 30-387 Krakow, Poland
| | - Joanna Rutkowska
- Institute of Environmental Sciences, Faculty of Biology, Jagiellonian University, 30-387 Krakow, Poland
| | - Dominika Wloch-Salamon
- Institute of Environmental Sciences, Faculty of Biology, Jagiellonian University, 30-387 Krakow, Poland
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3
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Epremyan KK, Mamaev DV, Zvyagilskaya RA. Alzheimer's Disease: Significant Benefit from the Yeast-Based Models. Int J Mol Sci 2023; 24:9791. [PMID: 37372938 DOI: 10.3390/ijms24129791] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2023] [Revised: 06/02/2023] [Accepted: 06/04/2023] [Indexed: 06/29/2023] Open
Abstract
Alzheimer's disease (AD) is an age-related, multifaceted neurological disorder associated with accumulation of aggregated proteins (amyloid Aβ and hyperphosphorylated tau), loss of synapses and neurons, and alterations in microglia. AD was recognized by the World Health Organization as a global public health priority. The pursuit of a better understanding of AD forced researchers to pay attention to well-defined single-celled yeasts. Yeasts, despite obvious limitations in application to neuroscience, show high preservation of basic biological processes with all eukaryotic organisms and offer great advantages over other disease models due to the simplicity, high growth rates on low-cost substrates, relatively simple genetic manipulations, the large knowledge base and data collections, and availability of an unprecedented amount of genomic and proteomic toolboxes and high-throughput screening techniques, inaccessible to higher organisms. Research reviewed above clearly indicates that yeast models, together with other, more simple eukaryotic models including animal models, C. elegans and Drosophila, significantly contributed to understanding Aβ and tau biology. These models allowed high throughput screening of factors and drugs that interfere with Aβ oligomerization, aggregation and toxicity, and tau hyperphosphorylation. In the future, yeast models will remain relevant, with a focus on creating novel high throughput systems to facilitate the identification of the earliest AD biomarkers among different cellular networks in order to achieve the main goal-to develop new promising therapeutic strategies to treat or prevent the disease.
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Affiliation(s)
- Khoren K Epremyan
- A.N. Bach Institute of Biochemistry, Research Center of Biotechnology of the Russian Academy of Sciences, Leninsky Ave. 33/2, 119071 Moscow, Russia
| | - Dmitry V Mamaev
- A.N. Bach Institute of Biochemistry, Research Center of Biotechnology of the Russian Academy of Sciences, Leninsky Ave. 33/2, 119071 Moscow, Russia
| | - Renata A Zvyagilskaya
- A.N. Bach Institute of Biochemistry, Research Center of Biotechnology of the Russian Academy of Sciences, Leninsky Ave. 33/2, 119071 Moscow, Russia
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Li X, Lao Z, Zou Y, Dong X, Li L, Wei G. Mechanistic Insights into the Co-Aggregation of Aβ and hIAPP: An All-Atom Molecular Dynamic Study. J Phys Chem B 2021; 125:2050-2060. [PMID: 33616398 DOI: 10.1021/acs.jpcb.0c11132] [Citation(s) in RCA: 26] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Abstract
Patients with Alzheimer's disease (AD) have a high risk of developing Type II diabetes (T2D). The co-aggregation of the two disease-related proteins, Aβ and hIAPP, has been proposed as a potential molecular mechanism. However, the detailed Aβ-hIAPP interactions and structural characteristics of co-aggregates are mostly unknown at atomic level. Here, we explore the conformational ensembles of the Aβ-hIAPP heterodimer and Aβ or hIAPP homodimer by performing all-atom explicit-solvent replica exchange molecular dynamic simulations. Our simulations show that the interaction propensity of Aβ-hIAPP in the heterodimer is comparable with that of Aβ-Aβ/hIAPP-hIAPP in the homodimer. Similar hot spot residues of Aβ/hIAPP in the homodimer and heterodimer are identified, indicating that both Aβ and hIAPP have similar molecular recognition sites for self-aggregation and co-aggregation. Aβ in the heterodimer possesses three high β-sheet probability regions: the N-terminal region E3-H6, the central hydrophobic core region K16-E22, and the C-terminal hydrophobic region I31-A41, which is highly similar to Aβ in the homodimer. More importantly, in the heterodimer, the regions E3-H6, F19-E22, and I31-M35 of Aβ and the amyloid core region N20-T30 of hIAPP display higher β-sheet probability than they do in homodimer, implying their crucial roles in the formation of β-sheet-rich co-aggregates. Our study sheds light on the co-aggregation of Aβ and hIAPP at an atomic level, which will be helpful for an in-depth understanding of the molecular mechanism for epidemiological correlation of AD and T2D.
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Affiliation(s)
- Xuhua Li
- State Key Laboratory of Surface Physics and Department of Physics, Fudan University, 2005 Songhu Road, Shanghai 200438, China.,MOE Key Laboratory for Nonequilibrium Synthesis and Modulation of Condensed Matter, School of Physics, Xi'an Jiaotong University, Xi'an 710049, China
| | - Zenghui Lao
- State Key Laboratory of Surface Physics and Department of Physics, Fudan University, 2005 Songhu Road, Shanghai 200438, China
| | - Yu Zou
- Department of Sport and Exercise Science, College of Education, Zhejiang University, 866 Yuhangtang Road, Hangzhou 310007 Zhejiang, China
| | - Xuewei Dong
- State Key Laboratory of Surface Physics and Department of Physics, Fudan University, 2005 Songhu Road, Shanghai 200438, China
| | - Le Li
- State Key Laboratory of Surface Physics and Department of Physics, Fudan University, 2005 Songhu Road, Shanghai 200438, China
| | - Guanghong Wei
- State Key Laboratory of Surface Physics and Department of Physics, Fudan University, 2005 Songhu Road, Shanghai 200438, China
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Jäkel L, Biemans EA, Klijn CJ, Kuiperij HB, Verbeek MM. Reduced Influence of apoE on Aβ43 Aggregation and Reduced Vascular Aβ43 Toxicity as Compared with Aβ40 and Aβ42. Mol Neurobiol 2020; 57:2131-2141. [PMID: 31953617 PMCID: PMC7118029 DOI: 10.1007/s12035-020-01873-x] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2019] [Accepted: 01/07/2020] [Indexed: 01/08/2023]
Abstract
The amyloid-β 43 (Aβ43) peptide has been shown to be abundantly expressed in Alzheimer's disease plaques, whereas only relatively low levels have been demonstrated in cerebral amyloid angiopathy (CAA). To better understand this discrepant distribution, we studied various biochemical properties of Aβ43, in comparison with Aβ40 and Aβ42. We assessed the interaction of Aβ43 with the three apoE isoforms (apoE2, apoE3, and apoE4) using SDS-PAGE/Western blotting and ELISA, aggregation propensity using thioflavin T assays, and cytotoxicity towards cerebrovascular cells using MTT assays. We found that Aβ43 did not differ from Aβ42 in its interaction with apoE, whereas Aβ40 had a significantly lower degree of interaction with apoE. At a molar ratio of 1:100 (apoE:Aβ), all apoE isoforms were comparably capable of inhibiting aggregation of Aβ40 and Aβ42, but not Aβ43. All Aβ variants had a concentration-dependent negative effect on metabolic activity of cerebrovascular cells. However, the degree of this effect differed for the three Aβ isoforms (Aβ40 > Aβ42 > Aβ43), with Aβ43 being the least cytotoxic peptide towards cerebrovascular cells. We conclude that Aβ43 has different biochemical characteristics compared with Aβ40 and Aβ42. Aggregation of Aβ43 is not inhibited by apoE, in contrast to the aggregation of Aβ40 and Aβ42. Furthermore, cerebrovascular cells are less sensitive towards Aβ43, compared with Aβ40 and Aβ42. In contrast, Aβ43 neither differed from Aβ42 in its aggregation propensity (in the absence of apoE) nor in its apoE-binding capacity. Altogether, our findings may provide an explanation for the lower levels of Aβ43 accumulation in cerebral vessel walls.
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Affiliation(s)
- Lieke Jäkel
- Department of Neurology, Donders Institute for Brain, Cognition and Behaviour, Radboud Alzheimer Centre, Radboud University Medical Center, Nijmegen, The Netherlands
- Department of Laboratory Medicine, Radboud University Medical Center, Nijmegen, The Netherlands
| | - Elisanne A.L.M. Biemans
- Department of Neurology, Donders Institute for Brain, Cognition and Behaviour, Radboud Alzheimer Centre, Radboud University Medical Center, Nijmegen, The Netherlands
- Department of Laboratory Medicine, Radboud University Medical Center, Nijmegen, The Netherlands
| | - Catharina J.M. Klijn
- Department of Neurology, Donders Institute for Brain, Cognition and Behaviour, Radboud Alzheimer Centre, Radboud University Medical Center, Nijmegen, The Netherlands
| | - H. Bea Kuiperij
- Department of Neurology, Donders Institute for Brain, Cognition and Behaviour, Radboud Alzheimer Centre, Radboud University Medical Center, Nijmegen, The Netherlands
- Department of Laboratory Medicine, Radboud University Medical Center, Nijmegen, The Netherlands
| | - Marcel M. Verbeek
- Department of Neurology, Donders Institute for Brain, Cognition and Behaviour, Radboud Alzheimer Centre, Radboud University Medical Center, Nijmegen, The Netherlands
- Department of Laboratory Medicine, Radboud University Medical Center, Nijmegen, The Netherlands
- Department of Neurology, Radboud University Medical Center, 830 TML, P.O. Box 9101, 6500 HB Nijmegen, The Netherlands
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Luu YN, Macreadie I. Development of Convenient System for Detecting Yeast Cell Stress, Including That of Amyloid Beta. Int J Mol Sci 2018; 19:E2136. [PMID: 30041424 PMCID: PMC6073510 DOI: 10.3390/ijms19072136] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2018] [Revised: 07/16/2018] [Accepted: 07/21/2018] [Indexed: 01/09/2023] Open
Abstract
(1) Background: As a model eukaryote, the study of stress responses in yeast can be employed for studying human health and disease, and the effects of various drugs that may impact health. "Reporting" of stress in yeast has frequently utilised enzymes like β-galactosidase that require laborious assays for quantitative results. The use of a stress reporter that can be measured quantitatively and with high sensitivity in living cells in a multi-well plate reader is a more desirable approach; (2) Methods: A multi-copy yeast-Escherichia coli shuttle plasmid containing the HSP42 promoter upstream of the mCherry reporter, along with the URA3 selectable marker was constructed and tested; (3) Results: Under certain stress conditions inducing the heat shock response, transformants containing the plasmid produced red fluorescence that could be readily quantitated in a microtitre plate reader. Stresses that produced red fluorescence included exposure to heat shock, copper ions, oligomeric amyloid beta (Aβ42) and fibrillar Aβ42; (4) Conclusions: Being able to conveniently and quantitatively monitor stresses in whole live populations of yeast offers great opportunities to screen compounds and conditions that cause stress, as well as conditions that alleviate stress. While freshly prepared oligomeric amyloid beta has previously been shown to exhibit high toxicity, fibrils have been generally considered to be non-toxic or of low toxicity. In this study, fibrillar amyloid beta has also been shown to induce stress.
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Affiliation(s)
- Yen Nhi Luu
- School of Science, RMIT University, Bundoora, VIC 3083, Australia.
| | - Ian Macreadie
- School of Science, RMIT University, Bundoora, VIC 3083, Australia.
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Amyloid Beta Peptide Is Released during Thrombosis in the Skin. Int J Mol Sci 2018; 19:ijms19061705. [PMID: 29890636 PMCID: PMC6032379 DOI: 10.3390/ijms19061705] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2018] [Revised: 06/04/2018] [Accepted: 06/06/2018] [Indexed: 12/12/2022] Open
Abstract
While it is known that amyloid beta (Aβ) deposits are found in different tissues of both Alzheimer’s disease (AD) patients and healthy individuals, there remain questions about the physiological role of these deposits, the origin of the Aβ peptide, and the mechanisms of its localization to the tissues. Using immunostaining with specific antibodies, as well as enzyme-linked immunosorbent assay, this study demonstrated Aβ40 peptide accumulation in the skin during local experimental photothrombosis in mice. Specifically, Aβ peptide accumulation was concentrated near the dermal blood vessels in thrombotic skin. It was also studied whether the released peptide affects microorganisms. Application of Aβ40 (4 µM) to the external membrane of yeast cells significantly increased membrane conductance with no visible effect on mouse host cells. The results suggest that Aβ release in the skin is related to skin injury and thrombosis, and occurs along with clotting whenever skin is damaged. These results support the proposition that Aβ release during thrombosis serves as part of a natural defense against infection.
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Affiliation(s)
- Ferenc Zsila
- Biomolecular Self-Assembly Group; Institute of Materials and Environmental Chemistry; Research Centre for Natural Sciences; Hungarian Academy of Sciences; 1117 Budapest Hungary
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9
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Amyloid growth and membrane damage: Current themes and emerging perspectives from theory and experiments on Aβ and hIAPP. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2018; 1860:1625-1638. [PMID: 29501606 DOI: 10.1016/j.bbamem.2018.02.022] [Citation(s) in RCA: 95] [Impact Index Per Article: 15.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/22/2017] [Revised: 02/21/2018] [Accepted: 02/21/2018] [Indexed: 12/15/2022]
Abstract
Alzheimer's Disease (AD) and Type 2 diabetes mellitus (T2DM) are two incurable diseases both hallmarked by an abnormal deposition of the amyloidogenic peptides Aβ and Islet Amyloid Polypeptide (IAPP) in affected tissues. Epidemiological data demonstrate that patients suffering from diabetes are at high risk of developing AD, thus making the search for factors common to the two pathologies of special interest for the design of new therapies. Accumulating evidence suggests that the toxic properties of both Aβ or IAPP are ascribable to their ability to damage the cell membrane. However, the molecular details describing Aβ or IAPP interaction with membranes are poorly understood. This review focuses on biophysical and in silico studies addressing these topics. Effects of calcium, cholesterol and membrane lipid composition in driving aberrant Aβ or IAPP interaction with the membrane will be specifically considered. The cross correlation of all these factors appears to be a key issue not only to shed light in the countless and often controversial reports relative to this area but also to gain valuable insights into the central events leading to membrane damage caused by amyloidogenic peptides. This article is part of a Special Issue entitled: Protein Aggregation and Misfolding at the Cell Membrane Interface edited by Ayyalusamy Ramamoorthy.
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Moosavi B, Mousavi B, Macreadie IG. Yeast Model of Amyloid-β and Tau Aggregation in Alzheimer's Disease. J Alzheimers Dis 2016; 47:9-16. [PMID: 26402750 DOI: 10.3233/jad-150173] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
The amyloid-β peptide (Aβ) and the phosphorylated protein tau have been widely implicated in Alzheimer's disease and are the focus of most research. Both agents have been extensively studied in mammalian cell culture and in animal studies, but new research is focusing on yeast models. Yeast are eukaryotes, just like us, and are amenable to effects and expression of Aβ and tau and appear able to 'report' with considerable relevance on the effects of these biomolecules. The use of yeast enables powerful new approaches to understanding how to overcome the effects of Aβ and tau, and such advances could lead to new therapies to prevent the progression of Alzheimer's disease.
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Affiliation(s)
- Behrooz Moosavi
- Key Laboratory of Pesticide & Chemical Biology, Ministry of Education, College of Chemistry, Central China Normal University, Wuhan, P.R. China
| | - Bibimaryam Mousavi
- Laboratory of Organometallics, Catalysis and Ordered Materials, State Key Laboratory of Advanced Technology for Materials Synthesis and Processing, Wuhan University of Technology, Wuhan, P.R. China
| | - Ian G Macreadie
- School of Applied Sciences, RMIT University, Bundoora, VIC, Australia
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Macreadie IG, Arvanitis C, Bharadwaj P. Finding chemopreventatives to reduce amyloid beta in yeast. Neural Regen Res 2016; 11:244-5. [PMID: 27073375 PMCID: PMC4810986 DOI: 10.4103/1673-5374.177729] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022] Open
Affiliation(s)
- Ian G Macreadie
- School of Science and Health Innovations Research Institute, RMIT University, Melbourne, Victoria, Australia
| | - Costa Arvanitis
- School of Science and Health Innovations Research Institute, RMIT University, Melbourne, Victoria, Australia
| | - Prashant Bharadwaj
- Centre of Excellence for Alzheimer's disease Research and Care, School of Medical Sciences, Edith Cowan University; CHIRI Biosciences Research Precinct, School of Biomedical Sciences, Curtin University, Perth, WA, Australia
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12
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Nuclear magnetic resonance evidence for the dimer formation of beta amyloid peptide 1-42 in 1,1,1,3,3,3-hexafluoro-2-propanol. Anal Biochem 2016; 498:59-67. [PMID: 26772162 DOI: 10.1016/j.ab.2015.12.021] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2015] [Revised: 12/04/2015] [Accepted: 12/29/2015] [Indexed: 01/05/2023]
Abstract
Alzheimer's disease involves accumulation of senile plaques in which filamentous aggregates of amyloid beta (Aβ) peptides are deposited. Recent studies demonstrate that oligomerization pathways of Aβ peptides may be complicated. To understand the mechanisms of Aβ(1-42) oligomer formation in more detail, we have established a method to produce (15)N-labeled Aβ(1-42) suited for nuclear magnetic resonance (NMR) studies. For physicochemical studies, the starting protein material should be solely monomeric and all Aβ aggregates must be removed. Here, we succeeded in fractionating a "precipitation-resistant" fraction of Aβ(1-42) from an "aggregation-prone" fraction by high-performance liquid chromatography (HPLC), even from bacterially overexpressed Aβ(1-42). However, both Aβ(1-42) fractions after 1,1,1,3,3,3-hexafluoro-2-propanol (HFIP) treatment formed amyloid fibrils. This indicates that the "aggregation seed" was not completely monomerized during HFIP treatment. In addition, Aβ(1-42) dissolved in HFIP was found to display a monomer-dimer equilibrium, as shown by two-dimensional (1)H-(15)N NMR. We demonstrated that the initial concentration of Aβ during the HFIP pretreatment altered the kinetic profiles of Aβ fibril formation in a thioflavin T fluorescence assay. The findings described here should ensure reproducible results when studying the Aβ(1-42) peptide.
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Porzoor A, Alford B, Hügel HM, Grando D, Caine J, Macreadie I. Anti-amyloidogenic properties of some phenolic compounds. Biomolecules 2015; 5:505-27. [PMID: 25898401 PMCID: PMC4496683 DOI: 10.3390/biom5020505] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2015] [Revised: 04/02/2015] [Accepted: 04/03/2015] [Indexed: 12/23/2022] Open
Abstract
A family of 21 polyphenolic compounds consisting of those found naturally in danshen and their analogues were synthesized and subsequently screened for their anti-amyloidogenic activity against the amyloid beta peptide (Aβ42) of Alzheimer’s disease. After 24 h incubation with Aβ42, five compounds reduced thioflavin T (ThT) fluorescence, indicative of their anti-amyloidogenic propensity (p < 0.001). TEM and immunoblotting analysis also showed that selected compounds were capable of hindering fibril formation even after prolonged incubations. These compounds were also capable of rescuing the yeast cells from toxic changes induced by the chemically synthesized Aβ42. In a second assay, a Saccharomyces cerevisiae AHP1 deletant strain transformed with GFP fused to Aβ42 was treated with these compounds and analyzed by flow cytometry. There was a significant reduction in the green fluorescence intensity associated with 14 compounds. We interpret this result to mean that the compounds had an anti-amyloid-aggregation propensity in the yeast and GFP-Aβ42 was removed by proteolysis. The position and not the number of hydroxyl groups on the aromatic ring was found to be the most important determinant for the anti-amyloidogenic properties.
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Affiliation(s)
- Afsaneh Porzoor
- School of Applied Sciences, RMIT University, Bundoora, Victoria 3083, Australia.
| | - Benjamin Alford
- School of Applied Sciences, RMIT University, Melbourne, Victoria 3000, Australia.
| | - Helmut M Hügel
- School of Applied Sciences, RMIT University, Melbourne, Victoria 3000, Australia.
| | - Danilla Grando
- School of Applied Sciences, RMIT University, Bundoora, Victoria 3083, Australia.
| | - Joanne Caine
- Materials Science and Engineering, CSIRO Preventative Health Flagship, 343 Royal Parade, Parkville, Victoria 3052, Australia.
| | - Ian Macreadie
- School of Applied Sciences, RMIT University, Bundoora, Victoria 3083, Australia.
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