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Saha J, Ford BJ, Wang X, Boyd S, Morgan SE, Rangachari V. Sugar distributions on gangliosides guide the formation and stability of amyloid-β oligomers. Biophys Chem 2023; 300:107073. [PMID: 37413816 PMCID: PMC10529042 DOI: 10.1016/j.bpc.2023.107073] [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: 03/24/2023] [Revised: 06/25/2023] [Accepted: 06/27/2023] [Indexed: 07/08/2023]
Abstract
Aggregation of Aβ peptides is a key contributor to the etiology of Alzheimer's disease. Being intrinsically disordered, monomeric Aβ is susceptible to conformational excursions, especially in the presence of important interacting partners such as membrane lipids, to adopt specific aggregation pathways. Furthermore, components such as gangliosides in membranes and lipid rafts are known to play important roles in the adoption of pathways and the generation of discrete neurotoxic oligomers. Yet, what roles do carbohydrates on gangliosides play in this process remains unknown. Here, using GM1, GM3, and GD3 ganglioside micelles as models, we show that the sugar distributions and cationic amino acids within Aβ N-terminal region modulate oligomerization of Aβ temporally, and dictate the stability and maturation of oligomers. These results demonstrate the selectivity of sugar distributions on the membrane surface toward oligomerization of Aβ and thus implicate cell-selective enrichment of oligomers.
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Affiliation(s)
- Jhinuk Saha
- Department of Chemistry and Biochemistry, School of Mathematics and Natural Sciences, 118, College Dr Hattiesburg, MS 39402, USA
| | - Brea J Ford
- Department of Chemistry and Biochemistry, School of Mathematics and Natural Sciences, 118, College Dr Hattiesburg, MS 39402, USA
| | | | - Sydney Boyd
- Department of Chemistry and Biochemistry, School of Mathematics and Natural Sciences, 118, College Dr Hattiesburg, MS 39402, USA
| | | | - Vijayaraghavan Rangachari
- Department of Chemistry and Biochemistry, School of Mathematics and Natural Sciences, 118, College Dr Hattiesburg, MS 39402, USA; Center for Molecular and Cellular Biosciences, University of Southern Mississippi, Hattiesburg, MS 39406, USA.
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2
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Maroli N. Aquaporin-4 Mediated Aggregation of Alzheimer's Amyloid β-Peptide. ACS Chem Neurosci 2023; 14:2683-2698. [PMID: 37486638 DOI: 10.1021/acschemneuro.3c00233] [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] [Indexed: 07/25/2023] Open
Abstract
Clearance of Alzheimer's amyloid oligomers from the brain is crucial for preventing cell toxicity. Dementia complications arise as a result of apoptosis, which is caused by peptide plaques on the lipid surface of cells. Here, we employed all-atom and coarse-grained molecular dynamics simulations to investigate the aggregation of amyloid peptides at the lipid surface and the role of aquaporin-4 (AQP4) in facilitating peptide clearance from astrocytes. The network of protein-protein interactions through text mining revealed that the expression of AQP4 and amyloid aggregation were strongly correlated. It has also been revealed that the role of aquaporins in the etiology of Alzheimer's disease involves several interconnected proteins and pathways. The nature of aggregation at the surface of the 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphocholine (POPC) lipid bilayer was revealed by the interaction of amyloid oligomers. The membrane-bound pore region of AQP4 interacts with the peptide and slows its aggregation. This interaction maintains the helical content of the peptide while lowering its toxicity at the lipid surface. The hydrophobicity of the peptide also decreased because of these interactions, which may help in the removal of the peptide from astrocytes. Long-term coarse-grained MD simulations demonstrated different features of oligomer aggregation at the surface and strong oligomer attraction to AQP4, which inhibited aggregation. Additionally, the water dynamics of aquaporins demonstrate how the selectivity filter is broken to disrupt water flow. Our findings also provide insight into the physiological alterations in brain tissue associated with Alzheimer's disease, including water retention and increased water flow in the CSF. Furthermore, in vitro thioflavin fluorescence spectroscopy revealed a slower aggregation of the peptide in the presence of AQP4.
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Affiliation(s)
- Nikhil Maroli
- Computational Biology Division, DRDO Center for Life Science, Bharathiar University Campus, Coimbatore 641046, Tamil Nadu, India
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3
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Saha J, Ford BJ, Boyd S, Rangachari V. Sugar distributions on gangliosides guide the formation and stability of amyloid-β oligomers. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.05.09.540003. [PMID: 37214891 PMCID: PMC10197704 DOI: 10.1101/2023.05.09.540003] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
Aggregation of Aβ peptides has been known as a key contributor to the etiology of Alzheimer's disease. Being intrinsically disordered, the monomeric Aβ is susceptible to conformational excursions, especially in the presence of key interacting partners such as membrane lipids, to adopt specific aggregation pathways. Furthermore, key components such as gangliosides in membranes and lipid rafts are known to play important roles in the adoption of pathways and the generation of discrete neurotoxic oligomers. Yet, what roles the carbohydrates on gangliosides play in this process remains unknown. Here, using GM1, GM3, and GD3 ganglioside micelles as models, we show that the sugar distributions and cationic amino acids within Aβ N-terminal region modulate oligomerization of Aβ temporally, and dictate the stability and maturation of oligomers.
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4
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Lyubchenko YL. Protein Self-Assembly at the Liquid-Surface Interface. Surface-Mediated Aggregation Catalysis. J Phys Chem B 2023; 127:1880-1889. [PMID: 36812408 DOI: 10.1021/acs.jpcb.2c09029] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/24/2023]
Abstract
Protein self-assembly into aggregates of various morphologies is a ubiquitous phenomenon in physical chemistry and biophysics. The critical role of amyloid assemblies in the development of diseases, neurodegenerative diseases especially, highlights the importance of understanding the mechanistic picture of the self-assembly process. The translation of this knowledge to the development of efficient preventions and treatments for diseases requires designing experiments at conditions mimicking those in vivo. This Perspective reviews data satisfying two major requirements: membrane environment and physiologically low concentrations of proteins. Recent progress in experiments and computational modeling resulted in a novel model for the amyloid aggregation process at the membrane-liquid interface. The self-assembly under such conditions has a number of critical features, further understanding of which can lead to the development of efficient preventive means and treatments for Alzheimer's and other devastating neurodegenerative disorders.
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Affiliation(s)
- Yuri L Lyubchenko
- Department of Pharmaceutical Sciences, University of Nebraska Medical Center, Omaha, Nebraska 68198, United States
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5
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Saha J, Bose P, Dhakal S, Ghosh P, Rangachari V. Ganglioside-Enriched Phospholipid Vesicles Induce Cooperative Aβ Oligomerization and Membrane Disruption. Biochemistry 2022; 61:2206-2220. [PMID: 36173882 PMCID: PMC9840156 DOI: 10.1021/acs.biochem.2c00495] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023]
Abstract
A major hallmark of Alzheimer's disease (AD) is the accumulation of extracellular aggregates of amyloid-β (Aβ). Structural polymorphism observed among Aβ fibrils in AD brains seem to correlate with the clinical subtypes suggesting a link between fibril polymorphism and pathology. Since fibrils emerge from a templated growth of low-molecular-weight oligomers, understanding the factors affecting oligomer generation is important. Membrane lipids are key factors to influence early stages of Aβ aggregation and oligomer generation, which cause membrane disruption. We have previously demonstrated that conformationally discrete Aβ oligomers can be generated by modulating the charge, composition, and chain length of lipids and surfactants. Here, we extend our studies into liposomal models by investigating Aβ oligomerization on large unilamellar vesicles (LUVs) of total brain extracts (TBE), reconstituted lipid rafts (LRs), or 1,2-dimyristoyl-sn-glycero-3-phosphocholine (DMPC). Varying the vesicle composition by specifically increasing the amount of GM1 gangliosides as a constituent, we found that only GM1-enriched liposomes induce the formation of toxic, low-molecular-weight oligomers. Furthermore, we found that the aggregation on liposome surface and membrane disruption are highly cooperative and sensitive to membrane surface characteristics. Numerical simulations confirm such a cooperativity and reveal that GM1-enriched liposomes form twice as many pores as those formed in the absence GM1. Overall, this study uncovers mechanisms of cooperativity between oligomerization and membrane disruption under controlled lipid compositional bias, and refocuses the significance of the early stages of Aβ aggregation in polymorphism, propagation, and toxicity in AD.
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Affiliation(s)
- Jhinuk Saha
- Department of Chemistry and Biochemistry, School of Mathematics and Natural Sciences, University of Southern Mississippi, Hattiesburg, Mississippi 39406, United States
| | - Priyankar Bose
- Department of Computer Science, Virginia Commonwealth University, Richmond, Virginia 23220, United States
| | - Shailendra Dhakal
- Center for Molecular and Cellular Biosciences, University of Southern Mississippi, Hattiesburg, Mississippi 39406, United States
| | - Preetam Ghosh
- Department of Computer Science, Virginia Commonwealth University, Richmond, Virginia 23220, United States
| | - Vijayaraghavan Rangachari
- Department of Chemistry and Biochemistry, School of Mathematics and Natural Sciences, University of Southern Mississippi, Hattiesburg, Mississippi 39406, United States; Center for Molecular and Cellular Biosciences, University of Southern Mississippi, Hattiesburg, Mississippi 39406, United States
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6
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Ayyalasomayajula N, Bandaru LJM, Chetty CS, Dixit PK, Challa S. Mitochondria-Mediated Moderation of Apoptosis by EGCG in Cytotoxic Neuronal Cells Induced by Lead (Pb) and Amyloid Peptides. Biol Trace Elem Res 2022; 200:3582-3593. [PMID: 34796416 DOI: 10.1007/s12011-021-02959-w] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/23/2021] [Accepted: 10/05/2021] [Indexed: 10/19/2022]
Abstract
The developmental, epigenetic, and epidemiological studies on lead (Pb) toxicity have reported a strong connection between lead exposure and the progression of Alzheimer's disease (AD). The amyloid peptides were the main triggering elements, in the generation of extracellular plaques through which multiple cellular signaling events such as apoptosis and primarily oxidant-antioxidant balancing system will be affected, which leads to neuronal cell death. Our previous studies indicated that epigallocatechin gallate (EGCG), abundantly present in green tea, was found to be effective in alleviating the metal-induced neurotoxicity at the cellular level in terms of cell viability and apoptosis The aim of this study was to explore the protective mechanism of EGCG on the markers of oxidant-antioxidant system and mitochondria, which are involved in metal-induced neuronal cell death. Initially, the IC50 values for lead(Pb-5 µM), amyloid peptides (AP(1-40)-60 µM; AP(1-40)-8 µM), and EC50 value for EGCG(50 µM) were determined by both time- (12 h, 24 h, 48 h) and concentration-dependent manner and analyzed by MTT assay. The experimental groups were designed initially by treating with Pb and APs individually and in different combinations along with the presence of EGCG and are compared to the Pb and AP treated group without EGCG exposure. The cell lysates were used for analyzing oxidative stress markers by standardized laboratory protocol and the expression of mitochondrial markers such as VDAC and cytochrome C which were analyzed by both western blot and real-time PCR. Our results indicate that the EGCG-treated group has shown a significant increase in antioxidant marker expression levels (GSH, SOD, catalase, vitamin C) and a decrease in oxidative stress marker (NOS, MDA) levels when compared to the group without EGCG treatment (p < 0.05). Similarly, a significant decrease in expression levels of VDAC and cytochrome c were observed in the EGCG-treated group when compared to the group without EGCG treatment (p < 0.05). Our approach revealed that EGCG protects SH-SY5Y cells from Pb- and AP-induced cytotoxicity by regulating voltage-dependent anion channel (VDAC) expression and oxidant-antioxidant system and inhibits neuronal cell death.
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Affiliation(s)
| | | | - Chellu S Chetty
- Department of Natural Sciences, Savannah State University, Savannah, GA, USA
| | | | - Suresh Challa
- Department of Cell Biology, National Institute of Nutrition, Hyderabad, Telangana, 50007, India.
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7
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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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8
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Sanders HM, Jovcevski B, Marty MT, Pukala TL. Structural and mechanistic insights into amyloid-β and α-synuclein fibril formation and polyphenol inhibitor efficacy in phospholipid bilayers. FEBS J 2022; 289:215-230. [PMID: 34268903 PMCID: PMC8727495 DOI: 10.1111/febs.16122] [Citation(s) in RCA: 14] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2020] [Revised: 06/11/2021] [Accepted: 07/15/2021] [Indexed: 01/03/2023]
Abstract
Under certain cellular conditions, functional proteins undergo misfolding, leading to a transition into oligomers which precede the formation of amyloid fibrils. Misfolding proteins are associated with neurodegenerative diseases such as Alzheimer's and Parkinson's diseases. While the importance of lipid membranes in misfolding and disease aetiology is broadly accepted, the influence of lipid membranes during therapeutic design has been largely overlooked. This study utilized a biophysical approach to provide mechanistic insights into the effects of two lipid membrane systems (anionic and zwitterionic) on the inhibition of amyloid-β 40 and α-synuclein amyloid formation at the monomer, oligomer and fibril level. Large unilamellar vesicles (LUVs) were shown to increase fibrillization and largely decrease the effectiveness of two well-known polyphenol fibril inhibitors, (-)-epigallocatechin gallate (EGCG) and resveratrol; however, use of immunoblotting and ion mobility mass spectrometry revealed this occurs through varying mechanisms. Oligomeric populations in particular were differentially affected by LUVs in the presence of resveratrol, an elongation phase inhibitor, compared to EGCG, a nucleation targeted inhibitor. Ion mobility mass spectrometry showed EGCG interacts with or induces more compact forms of monomeric protein typical of off-pathway structures; however, binding is reduced in the presence of LUVs, likely due to partitioning in the membrane environment. Competing effects of the lipids and inhibitor, along with reduced inhibitor binding in the presence of LUVs, provide a mechanistic understanding of decreased inhibitor efficacy in a lipid environment. Together, this study highlights that amyloid inhibitor design may be misguided if effects of lipid membrane composition and architecture are not considered during development.
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Affiliation(s)
- Henry M. Sanders
- Department of Chemistry, School of Physical Sciences, The University of Adelaide, Adelaide, SA 5005, Australia,Department of Chemistry and Biochemistry, University of Arizona, Tucson, Arizona 85721, United States
| | - Blagojce Jovcevski
- Department of Chemistry, School of Physical Sciences, The University of Adelaide, Adelaide, SA 5005, Australia
| | - Michael T. Marty
- Department of Chemistry and Biochemistry, University of Arizona, Tucson, Arizona 85721, United States
| | - Tara L. Pukala
- Department of Chemistry, School of Physical Sciences, The University of Adelaide, Adelaide, SA 5005, Australia,Correspondence: Tara L. Pukala: School of Physical Sciences, The University of Adelaide, Adelaide, SA 5005, Australia; ; Tel. +61 8 8313 5497
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9
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Wang Z, Sharda N, Curran GL, Li L, Lowe VJ, Kandimalla KK. Semimechanistic Population Pharmacokinetic Modeling to Investigate Amyloid Beta Trafficking and Accumulation at the BBB Endothelium. Mol Pharm 2021; 18:4148-4161. [PMID: 34664956 DOI: 10.1021/acs.molpharmaceut.1c00549] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Elevated exposure to toxic amyloid beta (Aβ) peptides and consequent blood-brain barrier (BBB) dysfunction are believed to promote vasculopathy in Alzheimer's disease (AD). However, the accumulation kinetics of different Aβ isoforms within the BBB endothelium and how it drives BBB dysfunction are not clearly characterized. Using single positron emission computed tomography (SPECT)-computed tomography (CT) dynamic imaging coupled with population pharmacokinetic modeling, we investigated the accumulation kinetics of Aβ40 and Aβ42 in the BBB endothelium. Brain clearance was quantified after intracerebral administration of 125I-Aβ, and BBB-mediated transport was shown to account for 54% of 125I-Aβ40 total clearance. A brain influx study demonstrated lower values of both maximal rate (Vmax) and Michaelis constant (Km) for 125I-Aβ42 compared to 125I-Aβ40. Validated by a transcytosis study in polarized human BBB endothelial cell (hCMEC/D3) monolayers, model simulations demonstrated impaired exocytosis was responsible for inefficient permeability and enhanced accumulation of Aβ42 in the BBB endothelium. Further, both isoforms were shown to disrupt the exocytosis machinery of BBB endothelial cells so that a vicious cycle could be generated. The validated model was able to capture changes in Aβ steady-state levels in plasma as well as the brain during AD progression and allowed us to predict the kinetics of Aβ accumulation in the BBB endothelium.
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Affiliation(s)
- Zengtao Wang
- Department of Pharmaceutics and Brain Barriers Research Center, College of Pharmacy, University of Minnesota, Minneapolis, Minnesota 55455, United Sates
| | - Nidhi Sharda
- Department of Pharmaceutics and Brain Barriers Research Center, College of Pharmacy, University of Minnesota, Minneapolis, Minnesota 55455, United Sates
| | - Geoffry L Curran
- Department of Radiology, Mayo Clinic, Rochester, Minnesota 55905, United Sates
| | - Ling Li
- Department of Experimental and Clinical Pharmacology, College of Pharmacy, University of Minnesota, Minneapolis, Minnesota 55455, United Sates
| | - Val J Lowe
- Department of Radiology, Mayo Clinic, Rochester, Minnesota 55905, United Sates
| | - Karunya K Kandimalla
- Department of Pharmaceutics and Brain Barriers Research Center, College of Pharmacy, University of Minnesota, Minneapolis, Minnesota 55455, United Sates
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10
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Reflectometry and molecular dynamics study of the impact of cholesterol and melatonin on model lipid membranes. EUROPEAN BIOPHYSICS JOURNAL: EBJ 2021; 50:1025-1035. [PMID: 34357445 DOI: 10.1007/s00249-021-01564-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/23/2020] [Revised: 03/12/2021] [Accepted: 07/30/2021] [Indexed: 10/20/2022]
Abstract
The effect of melatonin and/or cholesterol on the structural properties of a model lipid bilayer prepared from 1,2-dioleoyl-sn-glycero-3-phosphocholine (DOPC) has been investigated both experimentally and via molecular dynamics (MD) simulations. Neutron reflectometry experiments performed with single supported membranes revealed changes in lipid bilayer thickness upon the introduction of additional components. While the presence of cholesterol led to an increase in membrane thickness, the opposite effect was observed in the case of melatonin. The results obtained are in a good agreement with MD simulations which provided further information on the organization of components within the systems examined, indicating a mechanism underlying the membranes' thickness changes due to cholesterol and melatonin that had been observed experimentally. Cholesterol and melatonin preferentially accumulate in different membrane regions, presumably affecting the conformation of lipid hydrophobic moieties differently, and in turn having distinct impacts on the structure of the entire membrane. Our findings may be relevant for understanding the effects of age-related changes in cholesterol and melatonin concentrations, including those in the brains of individuals with Alzheimer's disease.
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11
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Grigolato F, Arosio P. The role of surfaces on amyloid formation. Biophys Chem 2021; 270:106533. [PMID: 33529995 DOI: 10.1016/j.bpc.2020.106533] [Citation(s) in RCA: 40] [Impact Index Per Article: 13.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2020] [Revised: 12/18/2020] [Accepted: 12/18/2020] [Indexed: 01/02/2023]
Abstract
Interfaces can strongly accelerate or inhibit protein aggregation, destabilizing proteins that are stable in solution or, conversely, stabilizing proteins that are aggregation-prone. Although this behaviour is well-known, our understanding of the molecular mechanisms underlying surface-induced protein aggregation is still largely incomplete. A major challenge is represented by the high number of physico-chemical parameters involved, which are highly specific to the considered combination of protein, surface properties, and solution conditions. The key aspect determining the role of interfaces is the relative propensity of the protein to aggregate at the surface with respect to bulk. In this review, we discuss the multiple molecular determinants that regulate this balance. We summarize current experimental techniques aimed at characterizing protein aggregation at interfaces, and highlight the need to complement experimental analysis with theoretical modelling. In particular, we illustrate how chemical kinetic analysis can be combined with experimental methods to provide insights into the molecular mechanisms underlying surface-induced protein aggregation, under both stagnant and agitation conditions. We summarize recent progress in the study of important amyloids systems, focusing on selected relevant interfaces.
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Affiliation(s)
- Fulvio Grigolato
- Department of Chemistry and Applied Biosciences, Institute for Chemical and Bioengineering, ETH Zurich, Zurich 8093, Switzerland
| | - Paolo Arosio
- Department of Chemistry and Applied Biosciences, Institute for Chemical and Bioengineering, ETH Zurich, Zurich 8093, Switzerland.
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12
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Rofo F, Ugur Yilmaz C, Metzendorf N, Gustavsson T, Beretta C, Erlandsson A, Sehlin D, Syvänen S, Nilsson P, Hultqvist G. Enhanced neprilysin-mediated degradation of hippocampal Aβ42 with a somatostatin peptide that enters the brain. Am J Cancer Res 2021; 11:789-804. [PMID: 33391505 PMCID: PMC7738863 DOI: 10.7150/thno.50263] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2020] [Accepted: 10/13/2020] [Indexed: 12/21/2022] Open
Abstract
Background: Aggregation of the amyloid-beta (Aβ) peptide is one of the main neuropathological events in Alzheimer's disease (AD). Neprilysin is the major enzyme degrading Aβ, with its activity enhanced by the neuropeptide somatostatin (SST). SST levels are decreased in the brains of AD patients. The poor delivery of SST over the blood-brain barrier (BBB) and its extremely short half-life of only 3 min limit its therapeutic significance. Methods: We recombinantly fused SST to a BBB transporter binding to the transferrin receptor. Using primary neuronal cultures and neuroblastoma cell lines, the ability of the formed fusion protein to activate neprilysin was studied. SST-scFv8D3 was administered to mice overexpressing the Aβ-precursor protein (AβPP) with the Swedish mutation (APPswe) as a single injection or as a course of three injections over a 72 h period. Levels of neprilysin and Aβ were quantified using an Enzyme-linked immunosorbent assay (ELISA). Distribution of SST-scFv8D3 in the brain, blood and peripheral organs was studied by radiolabeling with iodine-125. Results: The construct, SST-scFv8D3, exhibited 120 times longer half-life than SST alone, reached the brain in high amounts when injected intravenously and significantly increased the brain concentration of neprilysin in APPswe mice. A significant decrease in the levels of membrane-bound Aβ42 was detected in the hippocampus and the adjacent cortical area after only three injections. Conclusion: With intravenous injections of our BBB permeable SST peptide, we were able to significantly increase the levels neprilysin, an effect that was followed by a significant and selective degradation of membrane-bound Aβ42 in the hippocampus. Being that membrane-bound Aβ triggers neuronal toxicity and the hippocampus is the central brain area in the progression of AD, the study has illuminated a new potential treatment paradigm with a promising safety profile targeting only the disease affected areas.
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13
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Highlighting the effect of amyloid beta assemblies on the mechanical properties and conformational stability of cell membrane. J Mol Graph Model 2020; 100:107670. [PMID: 32711259 DOI: 10.1016/j.jmgm.2020.107670] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2020] [Revised: 06/09/2020] [Accepted: 06/10/2020] [Indexed: 01/05/2023]
Abstract
Alzheimer disease (AD) is the most common cause of dementia, characterized by a progressive decline in cognitive function due to the abnormal aggregation and deposition of Amyloid beta (Aβ) fibrils in the brain of patients. In this context, the molecular mechanisms of protein misfolding and aggregation that are known to induce significant biophysical alterations in cells, including destabilization of plasma membranes, remain partially unclear. Physical interaction between the Aβ assemblies and the membrane leads to the disruption of the cell membrane in multiple ways including, surface carpeting, generation of transmembrane channels and detergent-like membrane dissolution. Understanding the impact of amyloidogenic protein in different stages of aggregation with the plasma membrane, plays a crucial role to fully elucidate the pathological mechanisms of AD. Within this framework, computer simulations represent a powerful tool able to shed lights on the interactions governing the structural influence of Aβ proteins on biological membrane. In this study, molecular dynamics (MD) simulations have been performed in order to characterize how POPC bilayer conformational and mechanical properties are affected by the interaction with Aβ11-42 peptide, oligomer and fibril.
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14
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Ahmed GAR, Khalil SKH, Hotaby WE, Abbas L, Farrag ARH, Aal WEA, Sherif HHA, Abdel-Rahman EA, Saber SH, Hassan M, Hassan MH, Balgoon M, Qusti S, Kotb M, Ali SS. ATR-IR and EPR spectroscopy for following the membrane restoration of isolated cortical synaptosomes in aluminium-induced Alzheimer's disease - Like rat model. Chem Phys Lipids 2020; 231:104931. [PMID: 32619464 DOI: 10.1016/j.chemphyslip.2020.104931] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2019] [Revised: 05/22/2020] [Accepted: 06/01/2020] [Indexed: 01/03/2023]
Abstract
Synaptosomal membrane peroxidation and alteration in its biophysical properties are associated with Aluminium (Al) toxicity that may lead to cognitive dysfunction and Alzheimer's disease (AD) like pathogenesis. Here we investigated the therapeutic potential of Lepedium sativum (LS) as a natural anti-inflammatory, antioxidant and as acetyl cholinesterase inhibitor in treating Al induced AD-like in rat model. We utilized ATR-IR spectroscopy to follow the restoration in the damaged membrane structure of isolated rat cortical synaptosomes and its biophysical properties, electron paramagnetic resonance (EPR) spin trapping to follow NADPH oxidase activity (NOX), and EPR spin labelling in response to LS treatment after Al intoxication. We measured the concentration of Ca2+ ions in rat cortical tissue by inductively coupled plasma (ICP), the brain atrophy/curing and hydrocephalus by magnetic resonance imaging (MRI) besides light microscope histopathology. Our results revealed significant increase in synaptosomal membrane rgidification, order, lipid packing, reactive oxygen species (ROS) production and Ca2+ ion concentration as a result of Al intoxication. The dramatic increase in Ca2+ ion concentration detected in AD group associated with the increase in synaptic membrane polarity and EPR-detected order S-parameter suggest that release of synaptic vesicles into synaptic cleft might be hindered. LS treatment reversed these changes in synaptic membranes, and rescued an observed deficit in the exploratory behaviour of AD group. Our results also strongly suggest that the synaptosomal membrane phospholipids that underwent free radical attacks mediated by AlCl3, due to greater NOX activity, was prevented in the LS group. The results of ATR-IR and EPR spectroscopic techniques recommend LS as a promising therapeutic agent against synaptic membrane alterations opening a new window for AD drug developers.
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Affiliation(s)
- Gehan A-R Ahmed
- Spectroscopy Dept., Physics Division, National Research Centre, 33 El Bohouth St., (former El Tahrir St.), Dokki, Giza, P.O. 12622, Egypt; Biochemistry Dept., Faculty of Science, King Abdulaziz University, Jeddah, Saudi Arabia.
| | - Safaa K H Khalil
- Spectroscopy Dept., Physics Division, National Research Centre, 33 El Bohouth St., (former El Tahrir St.), Dokki, Giza, P.O. 12622, Egypt
| | - W El Hotaby
- Spectroscopy Dept., Physics Division, National Research Centre, 33 El Bohouth St., (former El Tahrir St.), Dokki, Giza, P.O. 12622, Egypt
| | - Lamyaa Abbas
- Spectroscopy Dept., Physics Division, National Research Centre, 33 El Bohouth St., (former El Tahrir St.), Dokki, Giza, P.O. 12622, Egypt
| | | | - Wafaa E Abdel Aal
- Pathology Dept., Medical Research Div., National Research Centre, Giza, Egypt
| | - Hadeer H A Sherif
- Spectroscopy Dept., Physics Division, National Research Centre, 33 El Bohouth St., (former El Tahrir St.), Dokki, Giza, P.O. 12622, Egypt
| | - Engy A Abdel-Rahman
- Center for Aging and Associated Diseases, Helmy Institute of Medical Sciences, Zewail City of Science and Technology, Giza, Egypt; Pharmacology Department, Faculty of Medicine, Assuit University, Assuit, Egypt; Children's Cancer Hospital 57357, Cair, Egypt
| | - Saber H Saber
- Center for Aging and Associated Diseases, Helmy Institute of Medical Sciences, Zewail City of Science and Technology, Giza, Egypt
| | - Mahmoud Hassan
- Center for Aging and Associated Diseases, Helmy Institute of Medical Sciences, Zewail City of Science and Technology, Giza, Egypt
| | - Mohamed H Hassan
- Centre for Materials Science, Zewail City of Science and Technology, Giza, Egypt
| | - Maha Balgoon
- Biochemistry Dept., Faculty of Science, King Abdulaziz University, Jeddah, Saudi Arabia
| | - Safaa Qusti
- Biochemistry Dept., Faculty of Science, King Abdulaziz University, Jeddah, Saudi Arabia
| | - Mamdooh Kotb
- Department of Radiology, King Abdulaziz University, Hospital, Jeddah, Saudi Arabia
| | - Sameh S Ali
- Center for Aging and Associated Diseases, Helmy Institute of Medical Sciences, Zewail City of Science and Technology, Giza, Egypt; Children's Cancer Hospital 57357, Cair, Egypt.
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15
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Menon S, Sengupta N, Das P. Nanoscale Interplay of Membrane Composition and Amyloid Self-Assembly. J Phys Chem B 2020; 124:5837-5846. [DOI: 10.1021/acs.jpcb.0c03796] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Affiliation(s)
- Sneha Menon
- Physical Chemistry Division, CSIR-National Chemical Laboratory, Pune 411008, India
- Academy of Scientific and Innovative Research (AcSIR), Ghaziabad 201002, India
| | - Neelanjana Sengupta
- Department of Biological Sciences, Indian Institute of Science Education and Research Kolkata, Mohanpur 741246, India
| | - Payel Das
- IBM Thomas J. Watson Research Center, Yorktown Heights, New York 10598, United States
- Applied Physics and Applied Math Department, Columbia University, New York, New York 10027, United States
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16
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Cavaco M, Valle J, da Silva R, Correia JD, Castanho MARB, Andreu D, Neves V. DPepH3, an Improved Peptide Shuttle for Receptor-independent Transport Across the Blood-Brain Barrier. Curr Pharm Des 2020; 26:1495-1506. [DOI: 10.2174/1381612826666200213094556] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2019] [Accepted: 01/23/2020] [Indexed: 12/13/2022]
Abstract
Background:The use of peptides as drug carriers across the blood-brain barrier (BBB) has increased significantly during the last decades. PepH3, a seven residue sequence (AGILKRW) derived from the α-helical domain of the dengue virus type-2 capsid protein, translocates across the BBB with very low toxicity. Somehow predictably from its size and sequence, PepH3 is degraded in serum relatively fast. Among strategies to increase peptide half-life (t1/2), the use of the enantiomer (wholly made of D-amino acid residues) can be quite successful if the peptide interacts with a target in non-stereospecific fashion.Methods:The goal of this work was the development of a more proteolytic-resistant peptide, while keeping the translocation properties. The serum stability, cytotoxicity, in vitro BBB translocation, and internalization mechanism of DPepH3 was assessed and compared to the native peptide.Results:DPepH3 demonstrates a much longer t1/2 compared to PepH3. We also confirm that BBB translocation is receptor-independent, which fully validates the enantiomer strategy chosen. In fact, we demonstrate that internalization occurs trough macropinocytosis. In addition, the enantiomer demonstrates to be non-cytotoxic towards endothelial cells as PepH3.Conclusion:DPepH3 shows excellent translocation and internalization properties, safety, and improved stability. Taken together, our results place DPepH3 at the forefront of the second generation of BBB shuttles.
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Affiliation(s)
- Marco Cavaco
- Instituto de Medicina Molecular, Faculdade de Medicina, Universidade de Lisboa, Av Prof Egas Moniz, 1649-028 Lisboa, Portugal
| | - Javier Valle
- Proteomics and Protein Chemistry Unit, Department of Experimental and Health Sciences, Pompeu Fabra University, Barcelona, Spain
| | - Ruben da Silva
- Centro de Ciencias e Tecnologias Nucleares and Departamento de Engenharia e Ciencias Nucleares, Instituto Superior Tecnico, Universidade de Lisboa, CTN, Estrada Nacional 10 (km 139,7), 2695-066 Bobadela LRS, Portugal
| | - João D.G. Correia
- Centro de Ciencias e Tecnologias Nucleares and Departamento de Engenharia e Ciencias Nucleares, Instituto Superior Tecnico, Universidade de Lisboa, CTN, Estrada Nacional 10 (km 139,7), 2695-066 Bobadela LRS, Portugal
| | - Miguel A. R. B Castanho
- Instituto de Medicina Molecular, Faculdade de Medicina, Universidade de Lisboa, Av Prof Egas Moniz, 1649-028 Lisboa, Portugal
| | - David Andreu
- Proteomics and Protein Chemistry Unit, Department of Experimental and Health Sciences, Pompeu Fabra University, Barcelona, Spain
| | - Vera Neves
- Instituto de Medicina Molecular, Faculdade de Medicina, Universidade de Lisboa, Av Prof Egas Moniz, 1649-028 Lisboa, Portugal
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17
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Das R, Balmik AA, Chinnathambi S. Effect of Melatonin on Tau aggregation and Tau-mediated cell surface morphology. Int J Biol Macromol 2020; 152:30-39. [PMID: 32044365 DOI: 10.1016/j.ijbiomac.2020.01.296] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2019] [Revised: 01/23/2020] [Accepted: 01/30/2020] [Indexed: 12/11/2022]
Abstract
Aggregation of Microtubule-associated protein Tau and its deposition in the form of neurofibrillary tangles (NFTs) is one of the pathological hallmarks of Alzheimer's disease (AD). Tau aggregation inhibition has been targeted in various studies including natural compounds and synthetic small molecules. Here, we have studied neurohormone- Melatonin against in vitro Tau aggregation and observed its effect on membrane topology, tubulin network and Tau phosphorylation in Neuro2A and N9 cell lines. The aggregation and conformation of Tau was determined by ThT fluorescence and CD spectroscopy respectively. The morphology of Tau aggregates in presence and absence of Melatonin was studied by transmission electron microscopy. Melatonin was found to reduce the formation of higher order oligomeric structures without affecting the overall aggregation kinetics of Tau. Melatonin also modulates and helps to maintain membrane morphology, independent on tubulin network as evidenced by FE-SEM and immunofluorescence analysis. Overall, Melatonin administration shows mild anti-aggregation and cytoprotective effects.
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Affiliation(s)
- Rashmi Das
- Neurobiology Group, Division of Biochemical Sciences, CSIR-National Chemical Laboratory, Dr. Homi Bhabha Road, 411008 Pune, India; Academy of Scientific and Innovative Research (AcSIR), 110025 New Delhi, India
| | - Abhishek Ankur Balmik
- Neurobiology Group, Division of Biochemical Sciences, CSIR-National Chemical Laboratory, Dr. Homi Bhabha Road, 411008 Pune, India; Academy of Scientific and Innovative Research (AcSIR), 110025 New Delhi, India
| | - Subashchandrabose Chinnathambi
- Neurobiology Group, Division of Biochemical Sciences, CSIR-National Chemical Laboratory, Dr. Homi Bhabha Road, 411008 Pune, India; Academy of Scientific and Innovative Research (AcSIR), 110025 New Delhi, India.
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18
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Genetic Dissection of Alzheimer's Disease Using Drosophila Models. Int J Mol Sci 2020; 21:ijms21030884. [PMID: 32019113 PMCID: PMC7037931 DOI: 10.3390/ijms21030884] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2020] [Revised: 01/26/2020] [Accepted: 01/26/2020] [Indexed: 02/06/2023] Open
Abstract
Alzheimer’s disease (AD), a main cause of dementia, is the most common neurodegenerative disease that is related to abnormal accumulation of the amyloid β (Aβ) protein. Despite decades of intensive research, the mechanisms underlying AD remain elusive, and the only available treatment remains symptomatic. Molecular understanding of the pathogenesis and progression of AD is necessary to develop disease-modifying treatment. Drosophila, as the most advanced genetic model, has been used to explore the molecular mechanisms of AD in the last few decades. Here, we introduce Drosophila AD models based on human Aβ and summarize the results of their genetic dissection. We also discuss the utility of functional genomics using the Drosophila system in the search for AD-associated molecular mechanisms in the post-genomic era.
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19
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β-Amyloid Peptide: the Cell Compartment Multi-faceted Interaction in Alzheimer's Disease. Neurotox Res 2019; 37:250-263. [PMID: 31811589 DOI: 10.1007/s12640-019-00116-9] [Citation(s) in RCA: 35] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2019] [Revised: 08/29/2019] [Accepted: 09/16/2019] [Indexed: 12/17/2022]
Abstract
Alzheimer's disease (AD) is the most widespread form of dementia, characterized by memory loss and reduction of cognitive functions that strongly interfere with normal daily life. Numerous evidences show that aggregates of the amyloid beta peptide, formed by 39 to 42 amino acid residues (Aβ39-43), from soluble small oligomers to large fibrils are characteristic markers of this pathology. However, AD is a complex disease and its neurodegenerative molecular mechanism is not yet fully understood. Growing evidence suggests a link between Aβ polymorphic nature, oligomers and fibrils, and specific mechanisms of neurodegeneration. The Aβ variable nature and its multiplicity of interactions with different proteins and organelles reflect the complexity of this pathology. In this review, we analyze the effects of the interaction between Aβ peptide and different cellular compartments in relation to the different kinds and sizes of amyloid aggregates. In particular, Aβ interaction with different cell structures such as the plasma membrane, mitochondria, lysosomes, nucleus, and endoplasmic reticulum is discussed. Further, we analyze the Aβ peptide ability to modify the structure and function of the target organelle, inducing alteration of its physiological role thus contributing to the pathological event. Dysfunction of cellular components terminating with the activation of the cellular death mechanism and subsequent neurodegeneration is also taken into consideration.
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20
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Grasso G, Leanza L, Morbiducci U, Danani A, Deriu MA. Aminoacid substitutions in the glycine zipper affect the conformational stability of amyloid beta fibrils. J Biomol Struct Dyn 2019; 38:3908-3915. [PMID: 31543007 DOI: 10.1080/07391102.2019.1671224] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
The aggregation of amyloid-beta peptides is associated with the pathogenesis of Alzheimer's disease. The hydrophobic core of the amyloid beta sequence contains a GxxxG repeated motif, called glycine zipper, which involves crucial residues for assuring stability and promoting the process of fibril formation. Mutations in this motif lead to a completely different oligomerization pathway and rate of fibril formation. In this work, we have tested G33L and G37L residue substitutions by molecular dynamics simulations. We found that both protein mutations may lead to remarkable changes in the fibril conformational stability. Results suggest the disruption of the glycine zipper as a possible strategy to reduce the aggregation propensity of amyloid beta peptides. On the basis of our data, further investigations may consider this key region as a binding site to design/discover novel effective inhibitors.Communicated by Ramaswamy H. Sarma.
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Affiliation(s)
- Gianvito Grasso
- Dalle Molle Institute for Artificial Intelligence (IDSIA), University of Applied Sciences of Southern Switzerland (SUPSI), University of Italian Switzerland (USI), Manno, Switzerland
| | - Luigi Leanza
- PolitoBIOMed Lab, Department of Mechanical and Aerospace Engineering, Politecnico di Torino, Italy
| | - Umberto Morbiducci
- PolitoBIOMed Lab, Department of Mechanical and Aerospace Engineering, Politecnico di Torino, Italy
| | - Andrea Danani
- Dalle Molle Institute for Artificial Intelligence (IDSIA), University of Applied Sciences of Southern Switzerland (SUPSI), University of Italian Switzerland (USI), Manno, Switzerland
| | - Marco A Deriu
- PolitoBIOMed Lab, Department of Mechanical and Aerospace Engineering, Politecnico di Torino, Italy
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21
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Fabiani C, Antollini SS. Alzheimer's Disease as a Membrane Disorder: Spatial Cross-Talk Among Beta-Amyloid Peptides, Nicotinic Acetylcholine Receptors and Lipid Rafts. Front Cell Neurosci 2019; 13:309. [PMID: 31379503 PMCID: PMC6657435 DOI: 10.3389/fncel.2019.00309] [Citation(s) in RCA: 90] [Impact Index Per Article: 18.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2019] [Accepted: 06/25/2019] [Indexed: 12/17/2022] Open
Abstract
Biological membranes show lateral and transverse asymmetric lipid distribution. Cholesterol (Chol) localizes in both hemilayers, but in the external one it is mostly condensed in lipid-ordered microdomains (raft domains), together with saturated phosphatidyl lipids and sphingolipids (including sphingomyelin and glycosphingolipids). Membrane asymmetries induce special membrane biophysical properties and behave as signals for several physiological and/or pathological processes. Alzheimer’s disease (AD) is associated with a perturbation in different membrane properties. Amyloid-β (Aβ) plaques and neurofibrillary tangles of tau protein together with neuroinflammation and neurodegeneration are the most characteristic cellular changes observed in this disease. The extracellular presence of Aβ peptides forming senile plaques, together with soluble oligomeric species of Aβ, are considered the major cause of the synaptic dysfunction of AD. The association between Aβ peptide and membrane lipids has been extensively studied. It has been postulated that Chol content and Chol distribution condition Aβ production and posterior accumulation in membranes and, hence, cell dysfunction. Several lines of evidence suggest that Aβ partitions in the cell membrane accumulate mostly in raft domains, the site where the cleavage of the precursor AβPP by β- and γ- secretase is also thought to occur. The main consequence of the pathogenesis of AD is the disruption of the cholinergic pathways in the cerebral cortex and in the basal forebrain. In parallel, the nicotinic acetylcholine receptor has been extensively linked to membrane properties. Since its transmembrane domain exhibits extensive contacts with the surrounding lipids, the acetylcholine receptor function is conditioned by its lipid microenvironment. The nicotinic acetylcholine receptor is present in high-density clusters in the cell membrane where it localizes mainly in lipid-ordered domains. Perturbations of sphingomyelin or cholesterol composition alter acetylcholine receptor location. Therefore, Aβ processing, Aβ partitioning, and acetylcholine receptor location and function can be manipulated by changes in membrane lipid biophysics. Understanding these mechanisms should provide insights into new therapeutic strategies for prevention and/or treatment of AD. Here, we discuss the implications of lipid-protein interactions at the cell membrane level in AD.
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Affiliation(s)
- Camila Fabiani
- Instituto de Investigaciones Bioquímicas de Bahía Blanca CONICET-UNS, Bahía Blanca, Argentina.,Departamento de Biología, Bioquímica y Farmacia, Universidad Nacional del Sur, Bahía Blanca, Argentina
| | - Silvia S Antollini
- Instituto de Investigaciones Bioquímicas de Bahía Blanca CONICET-UNS, Bahía Blanca, Argentina.,Departamento de Biología, Bioquímica y Farmacia, Universidad Nacional del Sur, Bahía Blanca, Argentina
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22
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Abstract
Membrane permeabilizing peptides (MPPs) are as ubiquitous as the lipid bilayer membranes they act upon. Produced by all forms of life, most membrane permeabilizing peptides are used offensively or defensively against the membranes of other organisms. Just as nature has found many uses for them, translational scientists have worked for decades to design or optimize membrane permeabilizing peptides for applications in the laboratory and in the clinic ranging from antibacterial and antiviral therapy and prophylaxis to anticancer therapeutics and drug delivery. Here, we review the field of membrane permeabilizing peptides. We discuss the diversity of their sources and structures, the systems and methods used to measure their activities, and the behaviors that are observed. We discuss the fact that "mechanism" is not a discrete or a static entity for an MPP but rather the result of a heterogeneous and dynamic ensemble of structural states that vary in response to many different experimental conditions. This has led to an almost complete lack of discrete three-dimensional active structures among the thousands of known MPPs and a lack of useful or predictive sequence-structure-function relationship rules. Ultimately, we discuss how it may be more useful to think of membrane permeabilizing peptides mechanisms as broad regions of a mechanistic landscape rather than discrete molecular processes.
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Affiliation(s)
- Shantanu Guha
- Department of Biochemistry and Molecular Biology Tulane University School of Medicine , New Orleans , Louisiana 70112 , United States
| | - Jenisha Ghimire
- Department of Biochemistry and Molecular Biology Tulane University School of Medicine , New Orleans , Louisiana 70112 , United States
| | - Eric Wu
- Department of Biochemistry and Molecular Biology Tulane University School of Medicine , New Orleans , Louisiana 70112 , United States
| | - William C Wimley
- Department of Biochemistry and Molecular Biology Tulane University School of Medicine , New Orleans , Louisiana 70112 , United States
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23
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Sahoo A, Xu H, Matysiak S. Pathways of amyloid-beta absorption and aggregation in a membranous environment. Phys Chem Chem Phys 2019; 21:8559-8568. [PMID: 30964132 DOI: 10.1039/c9cp00040b] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Aggregation of misfolded oligomeric amyloid-beta (Aβ) peptides on lipid membranes has been identified as a primary event in Alzheimer's pathogenesis. However, the structural and dynamical features of this membrane assisted Aβ aggregation have not been well characterized. The microscopic characterization of dynamic molecular-level interactions in peptide aggregation pathways has been challenging both computationally and experimentally. In this work, we explore differential patterns of membrane-induced Aβ 16-22 (K-L-V-F-F-A-E) aggregation from the microscopic perspective of molecular interactions. Physics-based coarse-grained molecular dynamics (CG-MD) simulations were employed to investigate the effect of lipid headgroup charge - zwitterionic (1-palmitoyl-2-oleoyl-sn-glycero-3-phosphocholine: POPC) and anionic (1-palmitoyl-2-oleoyl-sn-glycero-3-phospho-l-serine: POPS) - on Aβ 16-22 peptide aggregation. Our analyses present an extensive overview of multiple pathways for peptide absorption and biomechanical forces governing peptide folding and aggregation. In agreement with experimental observations, anionic POPS molecules promote extended configurations in Aβ peptides that contribute towards faster emergence of ordered β-sheet-rich peptide assemblies compared to POPC, suggesting faster fibrillation. In addition, lower cumulative rates of peptide aggregation in POPS due to higher peptide-lipid interactions and slower lipid diffusion result in multiple distinct ordered peptide aggregates that can serve as nucleation seeds for subsequent Aβ aggregation. This study provides an in-silico assessment of experimentally observed aggregation patterns, presents new morphological insights and highlights the importance of lipid headgroup chemistry in modulating the peptide absorption and aggregation process.
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Affiliation(s)
- Abhilash Sahoo
- Biophysics Program, Institute of Physical Science and Technology, University of Maryland, College Park, MD, USA.
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24
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Sun M, Zhao Y, Han M, Zhang B, Zhang X, Zhang Q, Lim NKH, Wang WA, Huang FD. TTC7 and Hyccin Regulate Neuronal Aβ42 Accumulation and its Associated Neural Deficits in Aβ42-Expressing Drosophila. J Alzheimers Dis 2018; 65:1001-1010. [PMID: 30103315 DOI: 10.3233/jad-170907] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
Neuronal amyloid-β (Aβ) accumulation plays an important role in the pathogenesis of Alzheimer's disease (AD). The conformation and toxicity of Aβ are regulated by lipids on the plasma membrane. Previously, we found downregulation of Rolling Blackout (RBO) or phosphatidylinositol-4-kinase type IIIα (PI4KIIIα) reduces neuronal Aβ accumulation and associated neural deficits in a Drosophila model expressing Aβ42. In mammals, the homologs of RBO and PI4KIIIα were reported to form a plasma membrane-localized complex with a scaffold protein TTC7 and cytosolic protein Hyccin/FAM126A to tightly control the plasmalemmal level of phosphatidylinositol-4-phosphate. Here, we show genetic downregulation of Drosophila TTC7 and Hyccin also reduces neuronal Aβ accumulation and associated synaptic and motor defects as well as premature death in Aβ42-expressing flies, while overexpression of TTC7 and Hyccin produced the opposite effect. These results, together with our previous study, demonstrate that RBO/TTC7/PI4KIIIα/Hyccin regulate neuronal Aβ accumulation and associated neural deficits in the Drosophila model, further supporting the RBO/Efr3-PI4KIIIα complex as a potential therapeutic target for AD.
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Affiliation(s)
- Minghao Sun
- Shanghai Advanced Research Institute, University of Chinese Academy of Sciences, Chinese Academy of Sciences, Shanghai, China
| | - Yinghui Zhao
- Shanghai Advanced Research Institute, University of Chinese Academy of Sciences, Chinese Academy of Sciences, Shanghai, China.,Laboratory of Molecular Neurobiology, School of Life Sciences, Shanghai University, Shanghai, China
| | - Men Han
- Department of Neurology, Qingdao Municipal Hospital, School of Medicine, Qingdao University, Qingdao, China
| | - Baozhu Zhang
- Shanghai Advanced Research Institute, University of Chinese Academy of Sciences, Chinese Academy of Sciences, Shanghai, China
| | - Xiao Zhang
- Shanghai Advanced Research Institute, University of Chinese Academy of Sciences, Chinese Academy of Sciences, Shanghai, China
| | - Qichao Zhang
- Shanghai Advanced Research Institute, University of Chinese Academy of Sciences, Chinese Academy of Sciences, Shanghai, China.,Sino-Danish College, University of Chinese Academy of Sciences, Chinese Academy of Sciences, Beijing, China
| | - Nastasia K-H Lim
- Shanghai Advanced Research Institute, University of Chinese Academy of Sciences, Chinese Academy of Sciences, Shanghai, China.,Shanghai Institute of Materia Medica, University of Chinese Academy of Sciences, Chinese Academy of Sciences, Shanghai, China
| | - Wen-An Wang
- Department of Neurology, Xinhua Hospital Chongming Branch Affiliated to Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Fu-De Huang
- Shanghai Advanced Research Institute, University of Chinese Academy of Sciences, Chinese Academy of Sciences, Shanghai, China.,Sino-Danish College, University of Chinese Academy of Sciences, Chinese Academy of Sciences, Beijing, China
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25
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Morris C, Cupples S, Kent TW, Elbassal EA, Wojcikiewicz EP, Yi P, Du D. N-Terminal Charged Residues of Amyloid-β Peptide Modulate Amyloidogenesis and Interaction with Lipid Membrane. Chemistry 2018; 24:9494-9498. [PMID: 29738067 PMCID: PMC6035087 DOI: 10.1002/chem.201801805] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2018] [Revised: 05/07/2018] [Indexed: 11/08/2022]
Abstract
Interactions of amyloid-β (Aβ) peptides and cellular membranes are proposed to be closely related with Aβ neurotoxicity in Alzheimer's disease. In this study, we systematically investigated the effect of the N-terminal hydrophilic region of Aβ40 on its amyloidogenesis and interaction with supported phospholipid bilayer. Our results show that modulation of the charge properties of the dynamic N-terminal region dramatically influences the aggregation properties of Aβ. Furthermore, our results demonstrate that the N-terminal charged residues play a crucial role in driving the early adsorption and latter remobilization of the peptide on membrane bilayer, and mediating the rigidity and viscoelasticity properties of the bound Aβ40 at the membrane interface. The results provide new mechanistic insight into the early Aβ-membrane interactions and binding, which may be critical for elucidating membrane-mediated Aβ amyloidogenesis in a physiological environment and unravelling the origin of Aβ neurotoxicity.
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Affiliation(s)
- Clifford Morris
- Department of Chemistry and Biochemistry, Florida Atlantic University, Boca Raton, FL, 33431, USA
| | - Shirin Cupples
- Department of Civil, Environmental and Geomatics Engineering, Florida Atlantic University, Boca Raton, FL, 33431, USA
- Department of Ocean and Mechanical Engineering, Florida Atlantic University, Boca Raton, FL, 33431, USA
| | - Thomas W Kent
- Department of Chemistry and Biochemistry, Florida Atlantic University, Boca Raton, FL, 33431, USA
| | - Esmail A Elbassal
- Department of Chemistry and Biochemistry, Florida Atlantic University, Boca Raton, FL, 33431, USA
| | - Ewa P Wojcikiewicz
- Department of Biomedical Science, Florida Atlantic University, Boca Raton, FL, 33431, USA
| | - Peng Yi
- Department of Civil, Environmental and Geomatics Engineering, Florida Atlantic University, Boca Raton, FL, 33431, USA
| | - Deguo Du
- Department of Chemistry and Biochemistry, Florida Atlantic University, Boca Raton, FL, 33431, USA
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26
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Cheng B, Li Y, Ma L, Wang Z, Petersen RB, Zheng L, Chen Y, Huang K. Interaction between amyloidogenic proteins and biomembranes in protein misfolding diseases: Mechanisms, contributors, and therapy. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2018; 1860:1876-1888. [PMID: 29466701 DOI: 10.1016/j.bbamem.2018.02.013] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/30/2017] [Revised: 02/12/2018] [Accepted: 02/13/2018] [Indexed: 12/14/2022]
Abstract
The toxic deposition of misfolded amyloidogenic proteins is associated with more than fifty protein misfolding diseases (PMDs), including Alzheimer's disease, Parkinson's disease and type 2 diabetes mellitus. Protein deposition is a multi-step process modulated by a variety of factors, in particular by membrane-protein interaction. The interaction results in permeabilization of biomembranes contributing to the cytotoxicity that leads to PMDs. Different biological and physiochemical factors, such as protein sequence, lipid composition, and chaperones, are known to affect the membrane-protein interaction. Here, we provide a comprehensive review of the mechanisms and contributing factors of the interaction between biomembranes and amyloidogenic proteins, and a summary of the therapeutic approaches to PMDs that target this interaction. 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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Affiliation(s)
- Biao Cheng
- Department of Pharmacy, The Central Hospital of Wuhan, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430023, China; Key Laboratory for Molecular Diagnosis of Hubei Province, The Central Hospital of Wuhan, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430023, China
| | - Yang Li
- Tongji School of Pharmacy, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430030, China
| | - Liang Ma
- Tongji School of Pharmacy, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430030, China
| | - Zhuoyi Wang
- Tongji School of Pharmacy, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430030, China
| | - Robert B Petersen
- Foundational Sciences, Central Michigan University College of Medicine, Mt. Pleasant, MI 48858, USA
| | - Ling Zheng
- Hubei Key Laboratory of Cell Homeostasis, College of Life Sciences, Wuhan 430072, China
| | - Yuchen Chen
- Tongji School of Pharmacy, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430030, China
| | - Kun Huang
- Tongji School of Pharmacy, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430030, China.
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27
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Bryksa BC, Yada RY. Protein Structure Insights into the Bilayer Interactions of the Saposin-Like Domain of Solanum tuberosum Aspartic Protease. Sci Rep 2017; 7:16911. [PMID: 29208977 PMCID: PMC5717070 DOI: 10.1038/s41598-017-16734-2] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2017] [Accepted: 11/16/2017] [Indexed: 12/26/2022] Open
Abstract
Many plant aspartic proteases contain a saposin-like domain whose principal functions are intracellular sorting and host defence. Its structure is characterised by helical segments cross-linked by three highly conserved cystines. The present study on the saposin-like domain of Solanum tuberosum aspartic protease revealed that acidification from inactive to active conditions causes dimerisation and a strand-to-helix secondary structure transition independent of bilayer interaction. Bilayer fusion was shown to occur under reducing conditions yielding a faster shift to larger vesicle sizes relative to native conditions, implying that a lower level structural motif might be bilayer-active. Characterisation of peptide sequences based on the domain’s secondary structural regions showed helix-3 to be active (~4% of the full domain’s activity), and mutation of its sole positively charged residue resulted in loss of activity and disordering of structure. Also, the peptides’ respective circular dichroism spectra suggested that native folding within the full domain is dependent on surrounding structure. Overall, the present study reveals that the aspartic protease saposin-like domain active structure is an open saposin fold dimer whose formation is pH-dependent, and that a bilayer-active motif shared among non-saposin membrane-active proteins including certain plant defence proteins is nested within an overall structure essential for native functionality.
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Affiliation(s)
- Brian C Bryksa
- Ontario Agricultural College, University of Guelph, N1G 2W1, Guelph, Ontario, Canada
| | - Rickey Y Yada
- Faculty of Land and Food Systems, University of British Columbia, Vancouver, V6T 1Z4, British Columbia, Canada.
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28
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Wongprayoon P, Govitrapong P. Melatonin as a mitochondrial protector in neurodegenerative diseases. Cell Mol Life Sci 2017; 74:3999-4014. [PMID: 28791420 PMCID: PMC11107580 DOI: 10.1007/s00018-017-2614-x] [Citation(s) in RCA: 48] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2017] [Accepted: 08/03/2017] [Indexed: 12/19/2022]
Abstract
Mitochondria are crucial organelles as their role in cellular energy production of eukaryotes. Because the brain cells demand high energy for maintaining their normal activities, disturbances in mitochondrial physiology may lead to neuropathological events underlying neurodegenerative conditions such as Alzheimer's disease, Parkinson's disease and Huntington's disease. Melatonin is an endogenous compound with a variety of physiological roles. In addition, it possesses potent antioxidant properties which effectively play protective roles in several pathological conditions. Several lines of evidence also reveal roles of melatonin in mitochondrial protection, which could prevent development and progression of neurodegeneration. Since the mitochondrial dysfunction is a primary event in neurodegeneration, the neuroprotection afforded by melatonin is thereby more effective in early stages of the diseases. This article reviews mechanisms which melatonin exerts its protective roles on mitochondria as a potential therapeutic strategy against neurodegenerative disorders.
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Affiliation(s)
- Pawaris Wongprayoon
- Department of Biopharmacy, Faculty of Pharmacy, Silpakorn University, Nakhon Pathom, 73000, Thailand
| | - Piyarat Govitrapong
- Research Center for Neuroscience, Institute of Molecular Biosciences, Mahidol University, Nakhon Pathom, 73170, Thailand.
- Chulabhorn Graduate Institute, Chulabhorn Royal Academy, Bangkok, 10210, Thailand.
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29
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Ngo ST, Nguyen MT, Nguyen NT, Vu VV. The Effects of A21G Mutation on Transmembrane Amyloid Beta (11–40) Trimer: An In Silico Study. J Phys Chem B 2017; 121:8467-8474. [DOI: 10.1021/acs.jpcb.7b05906] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Son Tung Ngo
- Computational
Chemistry Research Group, Ton Duc Thang University, Ho Chi Minh City, Vietnam
- Faculty
of Applied Sciences, Ton Duc Thang University, Ho Chi Minh City, Vietnam
| | - Minh Tung Nguyen
- Binh Duong University, Thu Dau Mot City, Binh Duong Province, Vietnam
| | - Nguyen Thanh Nguyen
- Department
of Theoretical Physics, University of Science, Ho Chi Minh City, Vietnam
| | - Van V. Vu
- NTT
Hi-Tech Institute, Nguyen Tat Thanh University, Ho Chi Minh City, Vietnam
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30
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Abstract
Previously published experimental studies have suggested that when the 40-residue amyloid beta peptide is encapsulated in a reverse micelle, it folds into a structure that may nucleate amyloid fibril formation (Yeung, P. S.-W.; Axelsen, P. H. J. Am. Chem. Soc. 2012, 134, 6061 ). The factors that induce the formation of this structure have now been identified in a multi-microsecond simulation of the same reverse micelle system that was studied experimentally. Key features of the polypeptide-micelle interaction include the anchoring of a hydrophobic residue cluster into gaps in the reverse micelle surface, the formation of a beta turn at the anchor point that brings N- and C-terminal segments of the polypeptide into proximity, high ionic strength that promotes intramolecular hydrogen bond formation, and deformation of the reverse micelle surface to facilitate interactions with the surface along the entire length of the polypeptide. Together, these features cause the simulation-derived vibrational spectrum to red shift in a manner that reproduces the red-shift previously reported experimentally. On the basis of these findings, a new mechanism is proposed whereby membranes nucleate fibril formation and facilitate the in-register alignment of polypeptide strands that is characteristic of amyloid fibrils.
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Affiliation(s)
- Gözde Eskici
- Department of Biochemistry & Biophysics, University of Pennsylvania Perelman School of Medicine , Philadelphia, Pennsylvania 19104, United States
| | - Paul H Axelsen
- Departments of Pharmacology, Biochemistry and Biophysics, and Medicine, University of Pennsylvania , Philadelphia, Pennsylvania 19104, United States
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31
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Lindberg DJ, Wesén E, Björkeroth J, Rocha S, Esbjörner EK. Lipid membranes catalyse the fibril formation of the amyloid-β (1-42) peptide through lipid-fibril interactions that reinforce secondary pathways. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2017; 1859:1921-1929. [PMID: 28564579 DOI: 10.1016/j.bbamem.2017.05.012] [Citation(s) in RCA: 76] [Impact Index Per Article: 10.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/25/2017] [Revised: 04/28/2017] [Accepted: 05/25/2017] [Indexed: 11/17/2022]
Abstract
Alzheimer's disease is associated with the aggregation of amyloid-β (Aβ) peptides into oligomers and fibrils. We have explored how model lipid membranes modulate the rate and mechanisms of Aβ(1-42) self-assembly, in order to shed light on how this pathological reaction may occur in the lipid-rich environments that the peptide encounters in the brain. Using a combination of in vitro biophysical experiments and theoretical approaches, we show that zwitterionic DOPC lipid vesicles accelerate the Aβ(1-42) fibril growth rate by interacting specifically with the growing fibrils. We probe this interaction with help of a purpose-developed Förster resonance energy transfer assay that monitors the proximity between a fibril-specific dye and fluorescent lipids in the lipid vesicle membrane. To further rationalise these findings we use mathematical models to fit the aggregation kinetics of Aβ(1-42) and find that lipid vesicles alter specific mechanistic steps in the aggregation reaction; they augment monomer-dependent secondary nucleation at the surface of existing fibrils and facilitate monomer-independent catalytic processes consistent with fibril fragmentation. We further show that DOPC vesicles have no effect on primary nucleation. This finding is consistent with experiments showing that Aβ(1-42) monomers do not directly bind to the lipid bilayer. Taken together, our results show that plain lipid membranes with charge and composition that is representative of outer cell membranes can significantly augment autocatalytic steps in the self-assembly of Aβ(1-42) into fibrils. This new insight suggests that strategies to reduce fibril-lipid interactions in the brain may have therapeutic value.
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Affiliation(s)
- David J Lindberg
- Division of Chemical Biology, Department of Biology and Biological Engineering, Chalmers University of Technology, Kemivägen 10, 412 96 Gothenburg, Sweden
| | - Emelie Wesén
- Division of Chemical Biology, Department of Biology and Biological Engineering, Chalmers University of Technology, Kemivägen 10, 412 96 Gothenburg, Sweden
| | - Johan Björkeroth
- Division of Chemical Biology, Department of Biology and Biological Engineering, Chalmers University of Technology, Kemivägen 10, 412 96 Gothenburg, Sweden
| | - Sandra Rocha
- Division of Chemical Biology, Department of Biology and Biological Engineering, Chalmers University of Technology, Kemivägen 10, 412 96 Gothenburg, Sweden
| | - Elin K Esbjörner
- Division of Chemical Biology, Department of Biology and Biological Engineering, Chalmers University of Technology, Kemivägen 10, 412 96 Gothenburg, Sweden.
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Downregulation of RBO-PI4KIIIα Facilitates Aβ 42 Secretion and Ameliorates Neural Deficits in Aβ 42-Expressing Drosophila. J Neurosci 2017; 37:4928-4941. [PMID: 28424219 DOI: 10.1523/jneurosci.3567-16.2017] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2016] [Revised: 03/12/2017] [Accepted: 03/31/2017] [Indexed: 12/25/2022] Open
Abstract
Phosphoinositides and their metabolizing enzymes are involved in Aβ42 metabolism and Alzheimer's disease pathogenesis. In yeast and mammals, Eighty-five requiring 3 (EFR3), whose Drosophila homolog is Rolling Blackout (RBO), forms a plasma membrane-localized protein complex with phosphatidylinositol-4-kinase Type IIIα (PI4KIIIα) and a scaffold protein to tightly control the level of plasmalemmal phosphatidylinositol-4-phosphate (PI4P). Here, we report that RBO binds to Drosophila PI4KIIIα, and that in an Aβ42-expressing Drosophila model, separate genetic reduction of PI4KIIIα and RBO, or pharmacological inhibition of PI4KIIIα ameliorated synaptic transmission deficit, climbing ability decline, premature death, and reduced neuronal accumulation of Aβ42 Moreover, we found that RBO-PI4KIIIa downregulation increased neuronal Aβ42 release and that PI4P facilitated the assembly or oligomerization of Aβ42 in/on liposomes. These results indicate that RBO-PI4KIIIa downregulation facilitates neuronal Aβ42 release and consequently reduces neuronal Aβ42 accumulation likely via decreasing Aβ42 assembly in/on plasma membrane. This study suggests the RBO-PI4KIIIα complex as a potential therapeutic target and PI4KIIIα inhibitors as drug candidates for Alzheimer's disease treatment.SIGNIFICANCE STATEMENT Phosphoinositides and their metabolizing enzymes are involved in Aβ42 metabolism and Alzheimer's disease pathogenesis. Here, in an Aβ42-expressing Drosophila model, we discovered and studied the beneficial role of downregulating RBO or its interacting protein PI4KIIIα-a protein that tightly controls the plasmalemmal level of PI4P-against the defects caused by Aβ42 expression. Mechanistically, RBO-PI4KIIIα downregulation reduced neuronal Aβ42 accumulation, and interestingly increased neuronal Aβ42 release. This study suggests the RBO-PI4KIIIα complex as a novel therapeutic target, and PI4KIIIα inhibitors as new drug candidates.
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Zhang M, Hu R, Ren B, Chen H, Jiang B, Ma J, Zheng J. Molecular Understanding of Aβ-hIAPP Cross-Seeding Assemblies on Lipid Membranes. ACS Chem Neurosci 2017; 8:524-537. [PMID: 27936589 DOI: 10.1021/acschemneuro.6b00247] [Citation(s) in RCA: 37] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023] Open
Abstract
Amyloid-β (Aβ) and human islet polypeptide (hIAPP) are the causative agents responsible for Alzheimer's disease (AD) and type II diabetes (T2D), respectively. While numerous studies have reported the cross-seeding behavior of Aβ and hIAPP in solution, little effort has been made to examine the cross-seeding of Aβ and hIAPP in the presence of cell membranes, which is more biologically relevant to the pathological link between AD and T2D. In this work, we computationally study the cross-seeding and adsorption behaviors of Aβ and hIAPP on zwitterionic POPC and anionic 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphocholine (POPC)/1-palmitoyl-2-oleoyl-sn-glycero-3-phosphatidylglycerol (POPG) mixed bilayers using all-atom molecular dynamics (MD) simulations, particularly aiming to the effects of the initial orientation of the Aβ-hIAPP assembly and the lipid composition of cell membranes on mutual structural and interaction changes in both Aβ-hIAPP assembly and lipid bilayers at the atomic level. Aβ-hIAPP cross-seeding assembly always preferred to adopt a specific orientation and interface to associate with both lipid bilayers strongly via the N-terminal strands of Aβ. Such membrane-bound orientation explains experimental observation that hybrid Aβ-hIAPP fibrils on cell membranes showed similar morphologies to pure hIAPP fibrils. Moreover, Aβ-hIAPP assembly, regardless of its initial orientations, interacted more strongly with POPC/POPG bilayer than POPC bilayer, indicating that electrostatic interactions are the major forces governing peptide-lipid interactions. Strong electrostatic interactions were also attributed to the formation of Ca2+ bridges connecting both negatively charged Glu of Aβ and PO4 head groups of lipids, which facilitate the association of Aβ-hIAPP with the POPC/POPG bilayer. It was also found that the strong peptide-lipid binding reduced lipid fluidity. Both facts imply that Aβ-hIAPP assembly may induce cell damage by altering calcium homeostasis and cell membrane phase. This work provides a better fundamental understanding of cross-seeding of Aβ and hIAPP on cell membranes and a potential pathological link between AD and T2D.
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Affiliation(s)
- Mingzhen Zhang
- Department of Chemical & Biomolecular Engineering, The University of Akron, Akron, Ohio 44325, United States
| | - Rundong Hu
- Department of Chemical & Biomolecular Engineering, The University of Akron, Akron, Ohio 44325, United States
| | - Baiping Ren
- Department of Chemical & Biomolecular Engineering, The University of Akron, Akron, Ohio 44325, United States
| | - Hong Chen
- Department of Chemical & Biomolecular Engineering, The University of Akron, Akron, Ohio 44325, United States
| | - Binbo Jiang
- Department of Chemical & Biomolecular Engineering, The University of Akron, Akron, Ohio 44325, United States
- College
of Chemical and Biological Engineering Zhejiang University, Hangzhou, Zhejiang 310027, China
| | - Jie Ma
- Department of Chemical & Biomolecular Engineering, The University of Akron, Akron, Ohio 44325, United States
- State
Key Laboratory of Pollution Control and Resource Reuse School of Environmental
Science and Engineering, Tongji University, Shanghai 200092, China
| | - Jie Zheng
- Department of Chemical & Biomolecular Engineering, The University of Akron, Akron, Ohio 44325, United States
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34
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Ngo ST, Hung HM, Tran KN, Nguyen MT. Replica exchange molecular dynamics study of the amyloid beta (11–40) trimer penetrating a membrane. RSC Adv 2017. [DOI: 10.1039/c6ra26461a] [Citation(s) in RCA: 30] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
The transmembrane Aβ11–40 trimer is investigated for the first time using REMD and FEP.
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Affiliation(s)
- Son Tung Ngo
- Computational Chemistry Research Group
- Ton Duc Thang University
- Ho Chi Minh City
- Vietnam
- Faculty of Applied Sciences
| | | | - Khoa Nhat Tran
- Department of Biological Sciences
- University of Maryland Baltimore County
- 21250 Baltimore
- USA
| | - Minh Tho Nguyen
- Computational Chemistry Research Group
- Ton Duc Thang University
- Ho Chi Minh City
- Vietnam
- Faculty of Applied Sciences
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35
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Thomaier M, Gremer L, Dammers C, Fabig J, Neudecker P, Willbold D. High-Affinity Binding of Monomeric but Not Oligomeric Amyloid-β to Ganglioside GM1 Containing Nanodiscs. Biochemistry 2016; 55:6662-6672. [DOI: 10.1021/acs.biochem.6b00829] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Affiliation(s)
- Maren Thomaier
- Institute
of Complex Systems (ICS-6), Structural Biochemistry, Forschungszentrum Jülich, 52425, Jülich, Germany
- Institut
für Physikalische Biologie, Heinrich-Heine-Universität Düsseldorf, 40225, Düsseldorf, Germany
| | - Lothar Gremer
- Institute
of Complex Systems (ICS-6), Structural Biochemistry, Forschungszentrum Jülich, 52425, Jülich, Germany
- Institut
für Physikalische Biologie, Heinrich-Heine-Universität Düsseldorf, 40225, Düsseldorf, Germany
| | - Christina Dammers
- Institute
of Complex Systems (ICS-6), Structural Biochemistry, Forschungszentrum Jülich, 52425, Jülich, Germany
| | - Judith Fabig
- Institute
of Complex Systems (ICS-6), Structural Biochemistry, Forschungszentrum Jülich, 52425, Jülich, Germany
| | - Philipp Neudecker
- Institute
of Complex Systems (ICS-6), Structural Biochemistry, Forschungszentrum Jülich, 52425, Jülich, Germany
- Institut
für Physikalische Biologie, Heinrich-Heine-Universität Düsseldorf, 40225, Düsseldorf, Germany
| | - Dieter Willbold
- Institute
of Complex Systems (ICS-6), Structural Biochemistry, Forschungszentrum Jülich, 52425, Jülich, Germany
- Institut
für Physikalische Biologie, Heinrich-Heine-Universität Düsseldorf, 40225, Düsseldorf, Germany
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36
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Breydo L, Redington JM, Uversky VN. Effects of Intrinsic and Extrinsic Factors on Aggregation of Physiologically Important Intrinsically Disordered Proteins. INTERNATIONAL REVIEW OF CELL AND MOLECULAR BIOLOGY 2016; 329:145-185. [PMID: 28109327 DOI: 10.1016/bs.ircmb.2016.08.011] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Misfolding and aggregation of proteins and peptides play an important role in a number of diseases as well as in many physiological processes. Many of the proteins that misfold and aggregate in vivo are intrinsically disordered. Protein aggregation is a complex multistep process, and aggregates can significantly differ in morphology, structure, stability, cytotoxicity, and self-propagation ability. The aggregation process is influenced by both intrinsic (e.g., mutations and expression levels) and extrinsic (e.g., polypeptide chain truncation, macromolecular crowding, posttranslational modifications, as well as interaction with metal ions, other small molecules, lipid membranes, and chaperons) factors. This review examines the effect of a variety of these factors on aggregation of physiologically important intrinsically disordered proteins.
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Affiliation(s)
- L Breydo
- Byrd Alzheimer's Research Institute, Morsani College of Medicine, University of South Florida, Tampa, FL, United States.
| | - J M Redington
- Byrd Alzheimer's Research Institute, Morsani College of Medicine, University of South Florida, Tampa, FL, United States
| | - V N Uversky
- Byrd Alzheimer's Research Institute, Morsani College of Medicine, University of South Florida, Tampa, FL, United States; Laboratory of Structural Dynamics, Stability and Folding of Proteins, Institute of Cytology, Russian Academy of Sciences, St. Petersburg, Russia.
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37
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Lockhart C, Klimov DK. The Alzheimer's disease A β peptide binds to the anionic DMPS lipid bilayer. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2016; 1858:1118-28. [DOI: 10.1016/j.bbamem.2016.03.001] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/24/2015] [Revised: 02/26/2016] [Accepted: 03/01/2016] [Indexed: 11/24/2022]
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38
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Membrane binding of peptide models for early stages of amyloid formation: Lipid packing counts more than charge. Chem Phys Lipids 2016; 198:28-38. [DOI: 10.1016/j.chemphyslip.2016.02.010] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2015] [Revised: 02/04/2016] [Accepted: 02/27/2016] [Indexed: 11/17/2022]
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39
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Delgado DA, Doherty K, Cheng Q, Kim H, Xu D, Dong H, Grewer C, Qiang W. Distinct Membrane Disruption Pathways Are Induced by 40-Residue β-Amyloid Peptides. J Biol Chem 2016; 291:12233-44. [PMID: 27056326 DOI: 10.1074/jbc.m116.720656] [Citation(s) in RCA: 48] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2016] [Indexed: 11/06/2022] Open
Abstract
Cellular membrane disruption induced by β-amyloid (Aβ) peptides has been considered one of the major pathological mechanisms for Alzheimer disease. Mechanistic studies of the membrane disruption process at a high-resolution level, on the other hand, are hindered by the co-existence of multiple possible pathways, even in simplified model systems such as the phospholipid liposome. Therefore, separation of these pathways is crucial to achieve an in-depth understanding of the Aβ-induced membrane disruption process. This study, which utilized a combination of multiple biophysical techniques, shows that the peptide-to-lipid (P:L) molar ratio is an important factor that regulates the selection of dominant membrane disruption pathways in the presence of 40-residue Aβ peptides in liposomes. Three distinct pathways (fibrillation with membrane content leakage, vesicle fusion, and lipid uptake through a temporarily stable ionic channel) become dominant in model liposome systems under specific conditions. These individual systems are characterized by both the initial states of Aβ peptides and the P:L molar ratio. Our results demonstrated the possibility to generate simplified Aβ-membrane model systems with a homogeneous membrane disruption pathway, which will benefit high-resolution mechanistic studies in the future. Fundamentally, the possibility of pathway selection controlled by P:L suggests that the driving forces for Aβ aggregation and Aβ-membrane interactions may be similar at the molecular level.
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Affiliation(s)
- Dennis A Delgado
- From the Department of Chemistry, State University of New York, Binghamton, New York 13902 and
| | - Katelynne Doherty
- From the Department of Chemistry, State University of New York, Binghamton, New York 13902 and
| | - Qinghui Cheng
- From the Department of Chemistry, State University of New York, Binghamton, New York 13902 and
| | - Hyeongeun Kim
- From the Department of Chemistry, State University of New York, Binghamton, New York 13902 and
| | - Dawei Xu
- the Department of Chemistry and Biomolecular Science, Clarkson University, Potsdam, New York 13699
| | - He Dong
- the Department of Chemistry and Biomolecular Science, Clarkson University, Potsdam, New York 13699
| | - Christof Grewer
- From the Department of Chemistry, State University of New York, Binghamton, New York 13902 and
| | - Wei Qiang
- From the Department of Chemistry, State University of New York, Binghamton, New York 13902 and
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40
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Maximally asymmetric transbilayer distribution of anionic lipids alters the structure and interaction with lipids of an amyloidogenic protein dimer bound to the membrane surface. Chem Phys Lipids 2016; 196:33-51. [PMID: 26827904 DOI: 10.1016/j.chemphyslip.2016.01.002] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2015] [Revised: 01/13/2016] [Accepted: 01/14/2016] [Indexed: 12/23/2022]
Abstract
We used molecular dynamics simulations to explore the effects of asymmetric transbilayer distribution of anionic phosphatidylserine (PS) lipids on the structure of a protein on the membrane surface and subsequent protein-lipid interactions. Our simulation systems consisted of an amyloidogenic, beta-sheet rich dimeric protein (D42) absorbed to the phosphatidylcholine (PC) leaflet, or protein-contact PC leaflet, of two membrane systems: a single-component PC bilayer and double PC/PS bilayers. The latter comprised of a stable but asymmetric transbilayer distribution of PS in the presence of counterions, with a 1-component PC leaflet coupled to a 1-component PS leaflet in each bilayer. The maximally asymmetric PC/PS bilayer had a non-zero transmembrane potential (TMP) difference and higher lipid order packing, whereas the symmetric PC bilayer had a zero TMP difference and lower lipid order packing under physiologically relevant conditions. Analysis of the adsorbed protein structures revealed weaker protein binding, more folding in the N-terminal domain, more aggregation of the N- and C-terminal domains and larger tilt angle of D42 on the PC leaflet surface of the PC/PS bilayer versus the PC bilayer. Also, analysis of protein-induced membrane structural disruption revealed more localized bilayer thinning in the PC/PS versus PC bilayer. Although the electric field profile in the non-protein-contact PS leaflet of the PC/PS bilayer differed significantly from that in the non-protein-contact PC leaflet of the PC bilayer, no significant difference in the electric field profile in the protein-contact PC leaflet of either bilayer was evident. We speculate that lipid packing has a larger effect on the surface adsorbed protein structure than the electric field for a maximally asymmetric PC/PS bilayer. Our results support the mechanism that the higher lipid packing in a lipid leaflet promotes stronger protein-protein but weaker protein-lipid interactions for a dimeric protein on membrane surfaces.
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41
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de Oliveira MR. Phloretin-induced cytoprotective effects on mammalian cells: A mechanistic view and future directions. Biofactors 2016; 42:13-40. [PMID: 26826024 DOI: 10.1002/biof.1256] [Citation(s) in RCA: 35] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/28/2015] [Accepted: 11/19/2015] [Indexed: 11/11/2022]
Abstract
Phloretin (C15 H14 O5 ), a dihydrochalcone flavonoid, is mainly found in fruit, leaves, and roots of apple tree. Phloretin exerts antioxidant, anti-inflammatory, and anti-tumor activities in mammalian cells through mechanisms that have been partially elucidated throughout the years. Phloretin bioavailability is well known in humans, but still remains to be better studied in experimental animals, such as mouse and rat. The focus of the present review is to gather information regarding the mechanisms involved in the phloretin-elicited effects in different in vitro and in vivo experimental models. Several manuscripts were analyzed and data raised by authors were described and discussed here in a mechanistic manner. Comparisons between the effects elicited by phloretin and phloridzin were made whenever possible, as well as with other polyphenols, clarifying questions about the use of phloretin as a potential therapeutic agent. Toxicological aspects associated to phloretin exposure were also discussed here. Furthermore, a special section containing future directions was created as a suggestive guide towards the elucidation of phloretin-related actions in mammalian cells and tissues.
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Affiliation(s)
- Marcos Roberto de Oliveira
- Department of Chemistry/ICET, Postgraduate Program in Chemistry (PPGQ), Federal University of Mato Grosso (UFMT), CEP, Cuiaba, MT, Brazil
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42
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Sugiura Y, Ikeda K, Nakano M. High Membrane Curvature Enhances Binding, Conformational Changes, and Fibrillation of Amyloid-β on Lipid Bilayer Surfaces. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2015; 31:11549-11557. [PMID: 26474149 DOI: 10.1021/acs.langmuir.5b03332] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
Aggregation of the amyloid-β (Aβ) protein and the formation of toxic aggregates are the possible pathogenic pathways in Alzheimer's disease. Accumulating evidence suggests that lipid membranes play key roles in protein aggregation, although the intermolecular forces that drive the interactions between Aβ-(1-40) and the membranes vary in different membrane systems. Here, we observed that a high positive curvature of lipid vesicles with diameters of ∼30 nm enhanced the association of Aβ with anionic phosphatidylglycerol membranes in the liquid-crystalline phase and with zwitterionic phosphatidylcholine membranes in the gel phase. The binding modes of Aβ to these membranes differ in terms of the location of the protein on the membrane and of the protein secondary structure. The fibrillation of Aβ was accelerated in the presence of the vesicles and at high protein-to-lipid ratios. Under these conditions, the protein accumulated on the surfaces, as demonstrated by a high (10(7) M(-1)) binding constant. Our findings suggest that packing defects on membranes with high curvatures, such as the intraluminal vesicles in multivesicular bodies and the exosomes, might result in the accumulation of toxic protein aggregates.
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Affiliation(s)
- Yuuki Sugiura
- Graduate School of Medicine and Pharmaceutical Sciences, University of Toyama , 2630 Sugitani, Toyama 930-0194, Japan
| | - Keisuke Ikeda
- Graduate School of Medicine and Pharmaceutical Sciences, University of Toyama , 2630 Sugitani, Toyama 930-0194, Japan
| | - Minoru Nakano
- Graduate School of Medicine and Pharmaceutical Sciences, University of Toyama , 2630 Sugitani, Toyama 930-0194, Japan
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Yi X, Zhang Y, Gong M, Yu X, Darabedian N, Zheng J, Zhou F. Ca2+ Interacts with Glu-22 of Aβ(1–42) and Phospholipid Bilayers to Accelerate the Aβ(1–42) Aggregation Below the Critical Micelle Concentration. Biochemistry 2015; 54:6323-32. [DOI: 10.1021/acs.biochem.5b00719] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Affiliation(s)
- Xinyao Yi
- Department
of Chemistry and Biochemistry, California State University, Los Angeles, California 90032, United States
- College
of Chemistry and Chemical Engineering, Central South University, Changsha, Hunan 410083, P. R. China
| | - Yi Zhang
- College
of Chemistry and Chemical Engineering, Central South University, Changsha, Hunan 410083, P. R. China
| | - Ming Gong
- Department
of Chemistry and Biochemistry, California State University, Los Angeles, California 90032, United States
| | - Xiang Yu
- Department
of Chemical and Biomolecular Engineering, The University of Akron, Akron, Ohio 44325, United States
| | - Narek Darabedian
- Department
of Chemistry and Biochemistry, California State University, Los Angeles, California 90032, United States
| | - Jie Zheng
- Department
of Chemical and Biomolecular Engineering, The University of Akron, Akron, Ohio 44325, United States
| | - Feimeng Zhou
- Department
of Chemistry and Biochemistry, California State University, Los Angeles, California 90032, United States
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Bonanomi M, Visentin C, Invernizzi G, Tortora P, Regonesi ME. The Toxic Effects of Pathogenic Ataxin-3 Variants in a Yeast Cellular Model. PLoS One 2015; 10:e0129727. [PMID: 26052945 PMCID: PMC4460139 DOI: 10.1371/journal.pone.0129727] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2014] [Accepted: 05/12/2015] [Indexed: 12/22/2022] Open
Abstract
Ataxin-3 (AT3) is a deubiquitinating enzyme that triggers an inherited neurodegenerative disorder, spinocerebellar ataxia type 3, when its polyglutamine (polyQ) stretch close to the C-terminus exceeds a critical length. AT3 variants carrying the expanded polyQ are prone to associate with each other into amyloid toxic aggregates, which are responsible for neuronal death with ensuing neurodegeneration. We employed Saccharomyces cerevisiae as a eukaryotic cellular model to better clarify the mechanism by which AT3 triggers the disease. We expressed three variants: one normal (Q26), one expanded (Q85) and one truncated for a region lying from the beginning of its polyQ stretch to the end of the protein (291Δ). We found that the expression of the expanded form caused reduction in viability, accumulation of reactive oxygen species, imbalance of the antioxidant defense system and loss in cell membrane integrity, leading to necrotic death. The truncated variant also exerted a qualitatively similar, albeit milder, effect on cell growth and cytotoxicity, which points to the involvement of also non-polyQ regions in cytotoxicity. Guanidine hydrochloride, a well-known inhibitor of the chaperone Hsp104, almost completely restored wild-type survival rate of both 291Δ- and Q85-expressing strains. This suggests that AT3 aggregation and toxicity is mediated by prion forms of yeast proteins, as this chaperone plays a key role in their propagation.
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Affiliation(s)
- Marcella Bonanomi
- Department of Biotechnologies and Biosciences, University of Milano-Bicocca, Milan, Italy
| | - Cristina Visentin
- Department of Biotechnologies and Biosciences, University of Milano-Bicocca, Milan, Italy
| | - Gaetano Invernizzi
- Department of Biotechnologies and Biosciences, University of Milano-Bicocca, Milan, Italy
| | - Paolo Tortora
- Department of Biotechnologies and Biosciences, University of Milano-Bicocca, Milan, Italy
- Milan Center of Neuroscience (NeuroMI), Milan, Italy
- * E-mail:
| | - Maria Elena Regonesi
- Milan Center of Neuroscience (NeuroMI), Milan, Italy
- Department of Statistics and Quantitative Methods, University of Milano-Bicocca, Milan, Italy
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Akinlolu RD, Nam M, Qiang W. Competition between Fibrillation and Induction of Vesicle Fusion for the Membrane-Associated 40-Residue β-Amyloid Peptides. Biochemistry 2015; 54:3416-9. [PMID: 25988500 DOI: 10.1021/acs.biochem.5b00321] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Abstract
Disruption of the cell membrane by the β-amyloid (Aβ) peptides has been considered as a main mechanism of Alzheimer's disease. The peptide-to-lipid molar ratio (P:L) varies over a broad range biologically. We report here that two of the previously observed Aβ evolution pathways, fibrillation and induction of vesicle fusion, compete with each other when P:L varies in model Aβ-liposome systems. Fibrillation is preferred at higher P:L values, and fusion is promoted at lower P:L values. Structural studies suggest that the same residues in Aβ may involve in both the initial fibrillation and membrane binding at the fusion sites.
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Affiliation(s)
- Rumonat D Akinlolu
- Department of Chemistry, State University of New York at Binghamton, Binghamton, New York 13902, United States
| | - Mimi Nam
- Department of Chemistry, State University of New York at Binghamton, Binghamton, New York 13902, United States
| | - Wei Qiang
- Department of Chemistry, State University of New York at Binghamton, Binghamton, New York 13902, United States
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46
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Lysophosphatidylcholine increases the neurotoxicity of Alzheimer's amyloid β1-42 peptide: role of oligomer formation. Neuroscience 2015; 292:159-69. [PMID: 25727637 DOI: 10.1016/j.neuroscience.2015.02.034] [Citation(s) in RCA: 38] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2014] [Revised: 02/16/2015] [Accepted: 02/19/2015] [Indexed: 11/24/2022]
Abstract
Oligomer formation is considered as a critical process for the neurotoxic effects of Alzheimer's amyloid β (Aβ) peptide. Previously we have demonstrated that lysophosphatidylcholine (LPC) increases the oligomer formation of Aβ1-42, the major Aβ peptide found Alzheimer's disease (AD) lesions. In this study, we have investigated whether LPC affects the neurotoxic effects of Aβ1-42 in a neuronal cell line (A1) culture. Dimethyl thiazolyl diphenyl tetrazolium (MTT) assay revealed that up to 10μM concentration, LPC did not affect A1 cell viability. Aβ1-42 decreased the cell viability, and such effect was dose dependently enhanced by LPC. However, neither LPC nor Aβ1-42, alone or in combination increased lactate dehydrogenase (LDH) release from A1 cells after 24-h treatment. Terminal deoxynucleotidyl transferase dUTP-biotin nick-end-labeling (TUNEL) assay showed that LPC increased Aβ1-42-induced apoptotic cell number. To determine the underlying mechanisms, the proteins implicated in apoptosis pathways including Bcl-2- and caspase-family were analyzed by Western blotting. The results demonstrated that Aβ1-42 decreased Bcl-2 in A1 cells at 24h, whereas LPC had no effect at any time point. Both LPC and Aβ1-42 increased Bax level at 24h, and their combined stimulation showed a synergistic effect. Similar synergistic effect of LPC and Aβ1-42 on caspase9 activation was observed. Dot blot immunoassay and Western blotting showed that LPC augmented Aβ1-42 oligomer formation in cell culture medium. Removing LPC-induced early-formed Aβ1-42 oligomer from the culture medium by immunoprecipitation decreased active caspase9 level and neurotoxicity, as revealed by Western blotting and MTT assay. Furthermore, dihydroethidium (DHE) assay showed that Aβ1-42 increased reactive oxygen species level in A1 cells, such effect was further enhanced by LPC. Thus, our results demonstrated that LPC increased the oligomer formation process of Aβ1-42 peptide in culture condition, and consequently increased apoptotic neuronal death. Such process might be important for the pathogenesis of AD, and inhibition of LPC generation could be a therapeutic target for the disease.
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Henry S, Vignaud H, Bobo C, Decossas M, Lambert O, Harte E, Alves ID, Cullin C, Lecomte S. Interaction of Aβ(1-42) amyloids with lipids promotes "off-pathway" oligomerization and membrane damage. Biomacromolecules 2015; 16:944-50. [PMID: 25689632 DOI: 10.1021/bm501837w] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
Abstract
The toxicity of amyloids, as Aβ(1-42) involved in Alzheimer disease, is a subject under intense scrutiny. Many studies link their toxicity to the existence of various intermediate structures prior to fiber formation and/or their specific interaction with membranes. In this study we focused on the interaction between membrane models and Aβ(1-42) peptides and variants (L34T, mG37C) produced in E. coli and purified in monomeric form. We evaluated the interaction of a toxic stable oligomeric form (oG37C) with membranes as comparison. Using various biophysical techniques as fluorescence and plasmon waveguide resonance, we clearly established that the oG37C interacts strongly with membranes leading to its disruption. All the studied peptides destabilized liposomes and accumulated slowly on the membrane (rate constant 0.02 min(-1)). Only the oG37C exhibited a particular pattern of interaction, comprising two steps: the initial binding followed by membrane reorganization. Cryo-TEM was used to visualize the peptide effect on liposome morphologies. Both oG37C and mG37C lead to PG membrane fragmentation. The PG membrane promotes peptide oligomerization, implicated in membrane disruption. WT (Aβ(1-42)) also perturbs liposome organization with membrane deformation rather than disruption. For all the peptides studied, their interaction with the membranes changes their fibrillization process, with less fibers and more small aggregates being formed. These studies allowed to establish, a correlation between toxicity, fiber formation, and membrane disruption.
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Affiliation(s)
- Sarah Henry
- Chimie et Biologie des Membranes et Nanoobjets, CBMN CNRS UMR 5248, Université de Bordeaux , Allée Geoffroy de Saint Hilaire, 33600 Pessac, France
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48
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Fibrillation of β amyloid peptides in the presence of phospholipid bilayers and the consequent membrane disruption. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2015; 1848:266-76. [DOI: 10.1016/j.bbamem.2014.04.011] [Citation(s) in RCA: 47] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/05/2014] [Revised: 03/24/2014] [Accepted: 04/13/2014] [Indexed: 01/27/2023]
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49
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Qiang W, Akinlolu RD, Nam M, Shu N. Structural evolution and membrane interaction of the 40-residue β amyloid peptides: differences in the initial proximity between peptides and the membrane bilayer studied by solid-state nuclear magnetic resonance spectroscopy. Biochemistry 2014; 53:7503-14. [PMID: 25397729 DOI: 10.1021/bi501003n] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Interactions between the β amyloid (Aβ) peptides and cellular membranes have severe consequences such as neuronal cell disruption and therefore may play important roles in Alzheimer's disease. Understanding the structural basis behind such interactions, however, is hindered by the complexity of the Aβ-membrane systems. In particular, because the Aβ peptides are partially incorporated in the membrane bilayer after enzymatic cleavage, there are multiple possibilities in terms of the initial proximity between the peptides and membranes. Structural studies using in vitro model systems with either externally added or preincorporated Aβ in membrane bilayers resulted in distinct evolution pathways. Previous work has shown that the externally added Aβ formed long and mature filaments, while preincorporated Aβ generated short and curvy fibrils. In this study, we perform detailed characterizations on the structural evolution and membrane interaction for these two pathways, using a combination of solid-state nuclear magnetic resonance spectroscopy and other techniques. For the externally added Aβ, we determined the residue-specific structural evolution during the fibrillation process. While the entire fibrillation process for the externally added Aβ was slow, the preincorporated Aβ generated Aβ-lipid complexes rapidly. Specific interactions between the lipids and peptides were observed, suggesting the colocalization of lipids and peptides within the complex. Formation of such a complex induced molecular-level changes in the lipid bilayer, which may serve as a possible mechanism of membrane disruption.
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Affiliation(s)
- Wei Qiang
- Department of Chemistry, Binghamton University, State University of New York , Binghamton, New York 13902, United States
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50
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Zhang M, Zhao J, Zheng J. Molecular understanding of a potential functional link between antimicrobial and amyloid peptides. SOFT MATTER 2014; 10:7425-7451. [PMID: 25105988 DOI: 10.1039/c4sm00907j] [Citation(s) in RCA: 76] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
Antimicrobial and amyloid peptides do not share common sequences, typical secondary structures, or normal biological activity but both the classes of peptides exhibit membrane-disruption ability to induce cell toxicity. Different membrane-disruption mechanisms have been proposed for antimicrobial and amyloid peptides, individually, some of which are not exclusive to either peptide type, implying that certain common principles may govern the folding and functions of different cytolytic peptides and associated membrane disruption mechanisms. Particularly, some antimicrobial and amyloid peptides have been identified to have dual complementary amyloid and antimicrobial properties, suggesting a potential functional link between amyloid and antimicrobial peptides. Given that some similar structural and membrane-disruption characteristics exist between the two classes of peptides, this review summarizes major findings, recent advances, and future challenges related to antimicrobial and amyloid peptides and strives to illustrate the similarities, differences, and relationships in the sequences, structures, and membrane interaction modes between amyloid and antimicrobial peptides, with a special focus on direct interactions of the peptides with the membranes. We hope that this review will stimulate further research at the interface of antimicrobial and amyloid peptides - which has been studied less intensively than either type of peptides - to decipher a possible link between both amyloid pathology and antimicrobial activity, which can guide drug design and peptide engineering to influence peptide-membrane interactions important in human health and diseases.
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Affiliation(s)
- Mingzhen Zhang
- Department of Chemical and Biomolecular Engineering, The University of Akron, Akron, Ohio 44325, USA.
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