1
|
Katina N, Marchenkov V, Ryabova N, Ilyina N, Marchenko N, Balobanov V, Finkelstein A. Influence of Amino Acid Substitutions in ApoMb on Different Stages of Unfolding of Amyloids. Molecules 2023; 28:7736. [PMID: 38067466 PMCID: PMC10707739 DOI: 10.3390/molecules28237736] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2023] [Revised: 11/19/2023] [Accepted: 11/21/2023] [Indexed: 12/18/2023] Open
Abstract
To date, most research on amyloid aggregation has focused on describing the structure of amyloids and the kinetics of their formation, while the conformational stability of fibrils remains insufficiently explored. The aim of this work was to investigate the effect of amino acid substitutions on the stability of apomyoglobin (ApoMb) amyloids. A study of the amyloid unfolding of ApoMb and its six mutant variants by urea has been carried out. Changes in the structural features of aggregates during unfolding were recorded by far-UV CD and native electrophoresis. It was shown that during the initial stage of denaturation, amyloids' secondary structure partially unfolds. Then, the fibrils undergo dissociation and form intermediate aggregates weighing approximately 1 MDa, which at the last stage of unfolding decompose into 18 kDa monomeric unfolded molecules. The results of unfolding transitions suggest that the stability of the studied amyloids relative to the intermediate aggregates and of the latter relative to unfolded monomers is higher for ApoMb variants with substitutions that increase the hydrophobicity of the residues. The results presented provide a new insight into the mechanism of stabilization of protein aggregates and can serve as a base for further investigations of the amyloids' stability.
Collapse
Affiliation(s)
- Natalya Katina
- Institute of Protein Research RAS, 142290 Pushchino, Russia; (V.M.); (N.R.); (N.I.); (N.M.)
- Branch of the Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry RAS, 142290 Pushchino, Russia
| | - Victor Marchenkov
- Institute of Protein Research RAS, 142290 Pushchino, Russia; (V.M.); (N.R.); (N.I.); (N.M.)
| | - Natalya Ryabova
- Institute of Protein Research RAS, 142290 Pushchino, Russia; (V.M.); (N.R.); (N.I.); (N.M.)
| | - Nelly Ilyina
- Institute of Protein Research RAS, 142290 Pushchino, Russia; (V.M.); (N.R.); (N.I.); (N.M.)
| | - Natalia Marchenko
- Institute of Protein Research RAS, 142290 Pushchino, Russia; (V.M.); (N.R.); (N.I.); (N.M.)
| | - Vitalii Balobanov
- Institute of Protein Research RAS, 142290 Pushchino, Russia; (V.M.); (N.R.); (N.I.); (N.M.)
| | - Alexey Finkelstein
- Institute of Protein Research RAS, 142290 Pushchino, Russia; (V.M.); (N.R.); (N.I.); (N.M.)
| |
Collapse
|
2
|
Nakajima K, Noi K, Yamaguchi K, So M, Ikenaka K, Mochizuki H, Ogi H, Goto Y. Optimized sonoreactor for accelerative amyloid-fibril assays through enhancement of primary nucleation and fragmentation. ULTRASONICS SONOCHEMISTRY 2021; 73:105508. [PMID: 33770746 PMCID: PMC7994783 DOI: 10.1016/j.ultsonch.2021.105508] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/12/2021] [Revised: 02/19/2021] [Accepted: 02/26/2021] [Indexed: 06/12/2023]
Abstract
Ultrasonication to supersaturated protein solutions forcibly forms amyloid fibrils, thereby allowing the early-stage diagnosis for amyloidoses. Previously, we constructed a high-throughput sonoreactor to investigate features of the amyloid-fibril nucleation. Although the instrument substantiated the ultrasonication efficacy, several challenges remain; the key is the precise control of the acoustic field in the reactor, which directly affects the fibril-formation reaction. In the present study, we develop the optimized sonoreactor for the amyloid-fibril assay, which improves the reproducibility and controllability of the fibril formation. Using β2-microglobulin, we experimentally demonstrate that achieving identical acoustic conditions by controlling oscillation amplitude and frequency of each transducer results in identical fibril-formation behavior across 36 solutions. Moreover, we succeed in detecting the 100-fM seeds using the developed sonoreactor at an accelerated rate. Finally, we reveal that the acceleration of the fibril-formation reaction with the seeds is achieved by enhancing the primary nucleation and the fibril fragmentation through the analysis of the fibril-formation kinetics. These results demonstrate the efficacy of the developed sonoreactor for the diagnosis of amyloidoses owing to the accelerative seed detection and the possibility for further early-stage diagnosis even without seeds through the accelerated primary nucleation.
Collapse
Affiliation(s)
- Kichitaro Nakajima
- Global Center for Medical Engineering and Informatics, Osaka University, Suita, Osaka 565-0871, Japan
| | - Kentaro Noi
- Institute for NanoScience Design, Osaka University, Toyonaka, Osaka 560-8531, Japan
| | - Keiichi Yamaguchi
- Global Center for Medical Engineering and Informatics, Osaka University, Suita, Osaka 565-0871, Japan
| | - Masatomo So
- Institute for Protein Research, Osaka University, Suita, Osaka 565-0871, Japan
| | - Kensuke Ikenaka
- Department of Neurology, Graduated School of Medicine, Osaka University, Suita, Osaka 565-0871, Japan
| | - Hideki Mochizuki
- Department of Neurology, Graduated School of Medicine, Osaka University, Suita, Osaka 565-0871, Japan
| | - Hirotsugu Ogi
- Graduate School of Engineering, Osaka University, Suita, Osaka 565-0871, Japan.
| | - Yuji Goto
- Global Center for Medical Engineering and Informatics, Osaka University, Suita, Osaka 565-0871, Japan.
| |
Collapse
|
3
|
Lin Y, Sahoo BR, Ozawa D, Kinoshita M, Kang J, Lim MH, Okumura M, Huh YH, Moon E, Jang JH, Lee HJ, Ryu KY, Ham S, Won HS, Ryu KS, Sugiki T, Bang JK, Hoe HS, Fujiwara T, Ramamoorthy A, Lee YH. Diverse Structural Conversion and Aggregation Pathways of Alzheimer's Amyloid-β (1-40). ACS NANO 2019; 13:8766-8783. [PMID: 31310506 DOI: 10.1021/acsnano.9b01578] [Citation(s) in RCA: 28] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
Complex amyloid aggregation of amyloid-β (1-40) (Aβ1-40) in terms of monomer structures has not been fully understood. Herein, we report the microscopic mechanism and pathways of Aβ1-40 aggregation with macroscopic viewpoints through tuning its initial structure and solubility. Partial helical structures of Aβ1-40 induced by low solvent polarity accelerated cytotoxic Aβ1-40 amyloid fibrillation, while predominantly helical folds did not aggregate. Changes in the solvent polarity caused a rapid formation of β-structure-rich protofibrils or oligomers via aggregation-prone helical structures. Modulation of the pH and salt concentration transformed oligomers to protofibrils, which proceeded to amyloid formation. We reveal diverse molecular mechanisms underlying Aβ1-40 aggregation with conceptual energy diagrams and propose that aggregation-prone partial helical structures are key to inducing amyloidogenesis. We demonstrate that context-dependent protein aggregation is comprehensively understood using the macroscopic phase diagram, which provides general insights into differentiation of amyloid formation and phase separation from unfolded and folded structures.
Collapse
Affiliation(s)
- Yuxi Lin
- Department of Chemistry , Sookmyung Women's University , Cheongpa-ro 47-gil 100 , Yongsan-gu, Seoul 04310 , South Korea
| | - Bikash R Sahoo
- Biophysics Program and Department of Chemistry, Biomedical Engineering, and Macromolecular Science and Engineering , University of Michigan , Ann Arbor , Michigan 48109-1055 , United States
| | - Daisaku Ozawa
- Department of Neurotherapeutics , Osaka University Graduate School of Medicine , 2-2 Yamadaoka , Suita , Osaka 565-0871 , Japan
| | - Misaki Kinoshita
- Frontier Research Institute for Interdisciplinary Sciences , Tohoku University , 6-3 Aramaki-Aza-Aoba , Aoba-ku, Sendai 980-8578 , Japan
| | - Juhye Kang
- Department of Chemistry , Korea Advanced Institute of Science and Technology , Daejeon 34141 , South Korea
- Department of Chemistry , Ulsan National Institute of Science and Technology , Ulsan 44919 , South Korea
| | - Mi Hee Lim
- Department of Chemistry , Korea Advanced Institute of Science and Technology , Daejeon 34141 , South Korea
| | - Masaki Okumura
- Frontier Research Institute for Interdisciplinary Sciences , Tohoku University , 6-3 Aramaki-Aza-Aoba , Aoba-ku, Sendai 980-8578 , Japan
| | | | | | | | - Hyun-Ju Lee
- Department of Neural Development and Disease , Korea Brain Research Institute , 61 Cheomdan-ro , Dong-gu, Daegu 41068 , South Korea
| | - Ka-Young Ryu
- Department of Neural Development and Disease , Korea Brain Research Institute , 61 Cheomdan-ro , Dong-gu, Daegu 41068 , South Korea
| | - Sihyun Ham
- Department of Chemistry , Sookmyung Women's University , Cheongpa-ro 47-gil 100 , Yongsan-gu, Seoul 04310 , South Korea
| | - Hyung-Sik Won
- Department of Biotechnology, Research Institute and College of Biomedical and Health Science , Konkuk University , Chungju , Chungbuk 27478 , South Korea
| | | | - Toshihiko Sugiki
- Institute for Protein Research , Osaka University , Yamadaoka 3-2 , Suita , Osaka 565-0871 , Japan
| | | | - Hyang-Sook Hoe
- Department of Neural Development and Disease , Korea Brain Research Institute , 61 Cheomdan-ro , Dong-gu, Daegu 41068 , South Korea
| | - Toshimichi Fujiwara
- Institute for Protein Research , Osaka University , Yamadaoka 3-2 , Suita , Osaka 565-0871 , Japan
| | - Ayyalusamy Ramamoorthy
- Biophysics Program and Department of Chemistry, Biomedical Engineering, and Macromolecular Science and Engineering , University of Michigan , Ann Arbor , Michigan 48109-1055 , United States
| | - Young-Ho Lee
- Institute for Protein Research , Osaka University , Yamadaoka 3-2 , Suita , Osaka 565-0871 , Japan
- Bio-Analytical Science , University of Science and Technology , Daejeon 34113 , South Korea
| |
Collapse
|
4
|
Reglodi D, Jungling A, Longuespée R, Kriegsmann J, Casadonte R, Kriegsmann M, Juhasz T, Bardosi S, Tamas A, Fulop BD, Kovacs K, Nagy Z, Sparks J, Miseta A, Mazzucchelli G, Hashimoto H, Bardosi A. Accelerated pre-senile systemic amyloidosis in PACAP knockout mice - a protective role of PACAP in age-related degenerative processes. J Pathol 2018; 245:478-490. [PMID: 29774542 PMCID: PMC6055756 DOI: 10.1002/path.5100] [Citation(s) in RCA: 27] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2017] [Revised: 04/10/2018] [Accepted: 05/12/2018] [Indexed: 12/14/2022]
Abstract
Dysregulation of neuropeptides may play an important role in aging‐induced impairments. Among them, pituitary adenylate cyclase‐activating polypeptide (PACAP) is a potent cytoprotective peptide that provides an endogenous control against a variety of tissue‐damaging stimuli. We hypothesized that the progressive decline of PACAP throughout life and the well‐known general cytoprotective effects of PACAP lead to age‐related pathophysiological changes in PACAP deficiency, supported by the increased vulnerability to various stressors of animals partially or totally lacking PACAP. Using young and aging CD1 PACAP knockout (KO) and wild type (WT) mice, we demonstrated pre‐senile amyloidosis in young PACAP KO animals and showed that senile amyloidosis appeared accelerated, more generalized, more severe, and affected more individuals. Histopathology showed age‐related systemic amyloidosis with mainly kidney, spleen, liver, skin, thyroid, intestinal, tracheal, and esophageal involvement. Mass spectrometry‐based proteomic analysis, reconfirmed with immunohistochemistry, revealed that apolipoprotein‐AIV was the main amyloid protein in the deposits together with several accompanying proteins. Although the local amyloidogenic protein expression was disturbed in KO animals, no difference was found in laboratory lipid parameters, suggesting a complex pathway leading to increased age‐related degeneration with amyloid deposits in the absence of PACAP. In spite of no marked inflammatory histological changes or blood test parameters, we detected a disturbed cytokine profile that possibly creates a pro‐inflammatory milieu favoring amyloid deposition. In summary, here we describe accelerated systemic senile amyloidosis in PACAP gene‐deficient mice, which might indicate an early aging phenomenon in this mouse strain. Thus, PACAP KO mice could serve as a model of accelerated aging with human relevance. © 2018 The Authors. The Journal of Pathology published by John Wiley & Sons Ltd on behalf of Pathological Society of Great Britain and Ireland.
Collapse
Affiliation(s)
- Dora Reglodi
- Department of Anatomy, MTA-PTE PACAP Research Group, University of Pecs Medical School, Pécs, Hungary
| | - Adel Jungling
- Department of Anatomy, MTA-PTE PACAP Research Group, University of Pecs Medical School, Pécs, Hungary
| | - Rémi Longuespée
- Institute of Pathology, University of Heidelberg, Heidelberg, Germany
| | - Joerg Kriegsmann
- Center for Histology, Cytology and Molecular Diagnostics, Trier, Germany.,Proteopath GmbH, Trier, Germany
| | | | - Mark Kriegsmann
- Institute of Pathology, University of Heidelberg, Heidelberg, Germany
| | - Tamas Juhasz
- Department of Anatomy, Histology and Embryology, Faculty of Medicine, University of Debrecen, Hungary
| | - Sebastian Bardosi
- Center for Histology, Cytology and Molecular Diagnostics, Trier, Germany
| | - Andrea Tamas
- Department of Anatomy, MTA-PTE PACAP Research Group, University of Pecs Medical School, Pécs, Hungary
| | - Balazs Daniel Fulop
- Department of Anatomy, MTA-PTE PACAP Research Group, University of Pecs Medical School, Pécs, Hungary
| | - Krisztina Kovacs
- Department of Biochemistry and Medical Chemistry, University of Pecs Medical School, Pécs, Hungary
| | - Zsuzsanna Nagy
- Second Department of Internal Medicine, University of Pecs Medical School, Pécs, Hungary
| | - Jason Sparks
- Department of Anatomy, MTA-PTE PACAP Research Group, University of Pecs Medical School, Pécs, Hungary
| | - Attila Miseta
- Department of Laboratory Medicine and Szentagothai Research Centre, University of Pecs Medical School, Pécs, Hungary
| | - Gabriel Mazzucchelli
- Laboratory of Mass Spectrometry (LSM) - MolSys, Department of Chemistry, University of Liège, Belgium
| | - Hitoshi Hashimoto
- Laboratory of Molecular Neuropharmacology, Graduate School of Pharmaceutical Sciences, Osaka University, Japan
| | - Attila Bardosi
- Center for Histology, Cytology and Molecular Diagnostics, Trier, Germany
| |
Collapse
|
5
|
Silva A, Almeida B, Fraga JS, Taboada P, Martins PM, Macedo-Ribeiro S. Distribution of Amyloid-Like and Oligomeric Species from Protein Aggregation Kinetics. Angew Chem Int Ed Engl 2017. [DOI: 10.1002/ange.201707345] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Affiliation(s)
- Alexandra Silva
- IBMC-Instituto de Biologia Molecular e Celular and I3s-Instituto de Investigação e Inovação em Saúde Portugal; Universidade do Porto; 4150-180 Porto Portugal
| | - Bruno Almeida
- IBMC-Instituto de Biologia Molecular e Celular and I3s-Instituto de Investigação e Inovação em Saúde Portugal; Universidade do Porto; 4150-180 Porto Portugal
- Present address: Life and Health Sciences Research Institute (ICVS); School of Medicine; University of Minho; 4710-057 Braga Portugal
- ICVS/3B's-PT Government Associate Laboratory; University of Minho; Braga/Guimarães Portugal
| | - Joana S. Fraga
- IBMC-Instituto de Biologia Molecular e Celular and I3s-Instituto de Investigação e Inovação em Saúde Portugal; Universidade do Porto; 4150-180 Porto Portugal
| | - Pablo Taboada
- Área de Física de la Materia Condensada; Facultad de Física; Universidad de Santiago de Compostela; Instituto de Investigación Sanitaria (IDIS) de Santiago de Compostela; Spain
| | - Pedro M. Martins
- IBMC-Instituto de Biologia Molecular e Celular and I3s-Instituto de Investigação e Inovação em Saúde Portugal; Universidade do Porto; 4150-180 Porto Portugal
- LEPABE-Departamento de Engenharia Química; Faculdade de Engenharia da Universidade do Porto; Rua Dr. Roberto Frias 4200-465 Porto Portugal
- ICBAS-Instituto de Ciências Biomédicas Abel Salazar; Universidade do Porto; Portugal
| | - Sandra Macedo-Ribeiro
- IBMC-Instituto de Biologia Molecular e Celular and I3s-Instituto de Investigação e Inovação em Saúde Portugal; Universidade do Porto; 4150-180 Porto Portugal
| |
Collapse
|
6
|
Silva A, Almeida B, Fraga JS, Taboada P, Martins PM, Macedo-Ribeiro S. Distribution of Amyloid-Like and Oligomeric Species from Protein Aggregation Kinetics. Angew Chem Int Ed Engl 2017; 56:14042-14045. [PMID: 28906069 DOI: 10.1002/anie.201707345] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2017] [Indexed: 12/13/2022]
Abstract
Amyloid fibrils and soluble oligomers are two types of protein aggregates associated with neurodegeneration. Classic therapeutic strategies try to prevent the nucleation and spread of amyloid fibrils, whilst diffusible oligomers have emerged as promising drug targets affecting downstream pathogenic processes. We developed a generic protein aggregation model and validate it against measured compositions of fibrillar and non-fibrillar assemblies of ataxin-3, a protein implicated in Machado-Joseph disease. The derived analytic rate-law equations can be used to 1) identify the presence of parallel aggregation pathways and 2) estimate the critical sizes of amyloid fibrils. The discretized population balance supporting our model is the first to quantitatively fit time-resolved measurements of size and composition of both amyloid-like and oligomeric species. The new theoretical framework can be used to screen a new class of drugs specifically targeting toxic oligomers.
Collapse
Affiliation(s)
- Alexandra Silva
- IBMC-Instituto de Biologia Molecular e Celular and I3s-Instituto de Investigação e Inovação em Saúde Portugal, Universidade do Porto, 4150-180, Porto, Portugal
| | - Bruno Almeida
- IBMC-Instituto de Biologia Molecular e Celular and I3s-Instituto de Investigação e Inovação em Saúde Portugal, Universidade do Porto, 4150-180, Porto, Portugal.,Present address: Life and Health Sciences Research Institute (ICVS), School of Medicine, University of Minho, 4710-057, Braga, Portugal.,ICVS/3B's-PT Government Associate Laboratory, University of Minho, Braga/Guimarães, Portugal
| | - Joana S Fraga
- IBMC-Instituto de Biologia Molecular e Celular and I3s-Instituto de Investigação e Inovação em Saúde Portugal, Universidade do Porto, 4150-180, Porto, Portugal
| | - Pablo Taboada
- Área de Física de la Materia Condensada, Facultad de Física, Universidad de Santiago de Compostela, Instituto de Investigación Sanitaria (IDIS) de Santiago de Compostela, Spain
| | - Pedro M Martins
- IBMC-Instituto de Biologia Molecular e Celular and I3s-Instituto de Investigação e Inovação em Saúde Portugal, Universidade do Porto, 4150-180, Porto, Portugal.,LEPABE-Departamento de Engenharia Química, Faculdade de Engenharia da Universidade do Porto, Rua Dr. Roberto Frias, 4200-465, Porto, Portugal.,ICBAS-Instituto de Ciências Biomédicas Abel Salazar, Universidade do Porto, Portugal
| | - Sandra Macedo-Ribeiro
- IBMC-Instituto de Biologia Molecular e Celular and I3s-Instituto de Investigação e Inovação em Saúde Portugal, Universidade do Porto, 4150-180, Porto, Portugal
| |
Collapse
|
7
|
So M, Hata Y, Naiki H, Goto Y. Heparin-induced amyloid fibrillation of β 2 -microglobulin explained by solubility and a supersaturation-dependent conformational phase diagram. Protein Sci 2017; 26:1024-1036. [PMID: 28249361 DOI: 10.1002/pro.3149] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2017] [Revised: 02/21/2017] [Accepted: 02/22/2017] [Indexed: 12/19/2022]
Abstract
Amyloid fibrils are fibrillar deposits of denatured proteins associated with amyloidosis and are formed by a nucleation and growth mechanism. We revisited an alternative and classical view of amyloid fibrillation: amyloid fibrils are crystal-like precipitates of denatured proteins formed above solubility upon breaking supersaturation. Various additives accelerate and then inhibit amyloid fibrillation in a concentration-dependent manner, suggesting that the combined effects of stabilizing and destabilizing forces affect fibrillation. Heparin, a glycosaminoglycan and anticoagulant, is an accelerator of fibrillation for various amyloidogenic proteins. By using β2 -microglobulin, a protein responsible for dialysis-related amyloidosis, we herein examined the effects of various concentrations of heparin on fibrillation at pH 2. In contrast to previous studies that focused on accelerating effects, higher concentrations of heparin inhibited fibrillation, and this was accompanied by amorphous aggregation. The two-step effects of acceleration and inhibition were similar to those observed for various salts. The results indicate that the anion effects caused by sulfate groups are one of the dominant factors influencing heparin-dependent fibrillation, although the exact structures of fibrils and amorphous aggregates might differ between those formed by simple salts and matrix-forming heparin. We propose that a conformational phase diagram, accommodating crystal-like amyloid fibrils and glass-like amorphous aggregates, is important for understanding the effects of various additives.
Collapse
Affiliation(s)
- Masatomo So
- Institute for Protein Research, Osaka University, Osaka, 565-0871, Japan
| | - Yasuko Hata
- Institute for Protein Research, Osaka University, Osaka, 565-0871, Japan
| | - Hironobu Naiki
- Faculty of Medical Sciences, University of Fukui, Fukui, 910-1193, Japan
| | - Yuji Goto
- Institute for Protein Research, Osaka University, Osaka, 565-0871, Japan
| |
Collapse
|
8
|
Korshavn KJ, Satriano C, Lin Y, Zhang R, Dulchavsky M, Bhunia A, Ivanova MI, Lee YH, La Rosa C, Lim MH, Ramamoorthy A. Reduced Lipid Bilayer Thickness Regulates the Aggregation and Cytotoxicity of Amyloid-β. J Biol Chem 2017; 292:4638-4650. [PMID: 28154182 DOI: 10.1074/jbc.m116.764092] [Citation(s) in RCA: 136] [Impact Index Per Article: 19.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2016] [Revised: 01/31/2017] [Indexed: 11/06/2022] Open
Abstract
The aggregation of amyloid-β (Aβ) on lipid bilayers has been implicated as a mechanism by which Aβ exerts its toxicity in Alzheimer's disease (AD). Lipid bilayer thinning has been observed during both oxidative stress and protein aggregation in AD, but whether these pathological modifications of the bilayer correlate with Aβ misfolding is unclear. Here, we studied peptide-lipid interactions in synthetic bilayers of the short-chain lipid dilauroyl phosphatidylcholine (DLPC) as a simplified model for diseased bilayers to determine their impact on Aβ aggregate, protofibril, and fibril formation. Aβ aggregation and fibril formation in membranes composed of dioleoyl phosphatidylcholine (DOPC) or 1- palmitoyl-2-oleoyl phosphatidylcholine mimicking normal bilayers served as controls. Differences in aggregate formation and stability were monitored by a combination of thioflavin-T fluorescence, circular dichroism, atomic force microscopy, transmission electron microscopy, and NMR. Despite the ability of all three lipid bilayers to catalyze aggregation, DLPC accelerates aggregation at much lower concentrations and prevents the fibrillation of Aβ at low micromolar concentrations. DLPC stabilized globular, membrane-associated oligomers, which could disrupt the bilayer integrity. DLPC bilayers also remodeled preformed amyloid fibrils into a pseudo-unfolded, molten globule state, which resembled on-pathway, protofibrillar aggregates. Whereas the stabilized, membrane-associated oligomers were found to be nontoxic, the remodeled species displayed toxicity similar to that of conventionally prepared aggregates. These results provide mechanistic insights into the roles that pathologically thin bilayers may play in Aβ aggregation on neuronal bilayers, and pathological lipid oxidation may contribute to Aβ misfolding.
Collapse
Affiliation(s)
- Kyle J Korshavn
- From the Department of Chemistry.,Program in Biophysics, and
| | - Cristina Satriano
- the Department of Chemical Sciences, University of Catania, Catania 95124, Italy
| | - Yuxi Lin
- the Institute for Protein Research, Osaka University, Osaka 565-0871, Japan
| | | | - Mark Dulchavsky
- Department of Neurology, University of Michigan, Ann Arbor, Michigan 48109
| | - Anirban Bhunia
- the Department of Biophysics, Bose Institute, Kolkata 700009, India, and
| | - Magdalena I Ivanova
- Program in Biophysics, and.,Department of Neurology, University of Michigan, Ann Arbor, Michigan 48109
| | - Young-Ho Lee
- the Institute for Protein Research, Osaka University, Osaka 565-0871, Japan
| | - Carmelo La Rosa
- the Department of Chemical Sciences, University of Catania, Catania 95124, Italy
| | - Mi Hee Lim
- the Department of Chemistry, Ulsan National Institute of Science and Technology (UNIST), Ulsan 44919, Korea
| | | |
Collapse
|