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Choi NR, Choi WG, Kwon MJ, Woo JH, Kim BJ. [6]-Gingerol induces Caspase-Dependent Apoptosis in Bladder Cancer cells via MAPK and ROS Signaling. Int J Med Sci 2022; 19:1093-1102. [PMID: 35919815 PMCID: PMC9339411 DOI: 10.7150/ijms.73077] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/21/2022] [Accepted: 06/09/2022] [Indexed: 11/05/2022] Open
Abstract
The anti-cancer effects of [6]-gingerol ([6]-GIN), the main active polyphenol of ginger (Zingiber officinale), were investigated in the human bladder cancer cell line 5637. [6]-GIN inhibited cell proliferation, increased sub‑G1 phase ratios, and depolarized mitochondrial membrane potential. [6]-GIN-induced cell death was associated with the downregulation of B‑cell lymphoma 2 (BCL‑2) and survivin and the upregulation of Bcl‑2‑associated X protein (Bax). [6]-GIN activated caspase‑3 and caspase-9 and regulated the activation of mitogen-activated protein kinases (MAPKs). Further, [6]-GIN also increased the intracellular reactive oxygen species (ROS) levels and TG100-115 or tranilast increased [6]-GIN‑induced cell death. These results suggest that [6]-GIN induced apoptosis in the bladder cancer cell line 5637 and therefore has the potential to be used in the development of new drugs for bladder cancer treatment.
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Affiliation(s)
- Na Ri Choi
- Division of Longevity and Biofunctional Medicine, Pusan National University School of Korean Medicine, Yangsan 50612, Republic of Korea
| | - Woo-gyun Choi
- Division of Longevity and Biofunctional Medicine, Pusan National University School of Korean Medicine, Yangsan 50612, Republic of Korea
| | - Min Ji Kwon
- Division of Longevity and Biofunctional Medicine, Pusan National University School of Korean Medicine, Yangsan 50612, Republic of Korea
| | - Joo Han Woo
- Department of Physiology, Dongguk University College of Medicine, Gyeongju, 38066. Republic of Korea
- Channelopathy Research Center (CRC), Dongguk University College of Medicine, 32 Dongguk-ro, Ilsan Dong-gu, Goyang, Gyeonggi-do, 10326. Republic of Korea
| | - Byung Joo Kim
- Division of Longevity and Biofunctional Medicine, Pusan National University School of Korean Medicine, Yangsan 50612, Republic of Korea
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2
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Liang T, Zhang Y, Wu S, Chen Q, Wang L. The Role of NLRP3 Inflammasome in Alzheimer’s Disease and Potential Therapeutic Targets. Front Pharmacol 2022; 13:845185. [PMID: 35250595 PMCID: PMC8889079 DOI: 10.3389/fphar.2022.845185] [Citation(s) in RCA: 46] [Impact Index Per Article: 23.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2021] [Accepted: 01/24/2022] [Indexed: 12/30/2022] Open
Abstract
Alzheimer’s disease (AD) is a common age-related neurodegenerative disease characterized by progressive cognitive dysfunction and behavioral impairment. The typical pathological characteristics of AD are extracellular senile plaques composed of amyloid ß (Aβ) protein, intracellular neurofibrillary tangles formed by the hyperphosphorylation of the microtubule-associated protein tau, and neuron loss. In the past hundred years, although human beings have invested a lot of manpower, material and financial resources, there is no widely recognized drug for the effective prevention and clinical cure of AD in the world so far. Therefore, evaluating and exploring new drug targets for AD treatment is an important topic. At present, researchers have not stopped exploring the pathogenesis of AD, and the views on the pathogenic factors of AD are constantly changing. Multiple evidence have confirmed that chronic neuroinflammation plays a crucial role in the pathogenesis of AD. In the field of neuroinflammation, the nucleotide-binding oligomerization domain-like receptor pyrin domain-containing 3 (NLRP3) inflammasome is a key molecular link in the AD neuroinflammatory pathway. Under the stimulation of Aβ oligomers and tau aggregates, it can lead to the assembly and activation of NLRP3 inflammasome in microglia and astrocytes in the brain, thereby causing caspase-1 activation and the secretion of IL-1β and IL-18, which ultimately triggers the pathophysiological changes and cognitive decline of AD. In this review, we summarize current literatures on the activation of NLRP3 inflammasome and activation-related regulation mechanisms, and discuss its possible roles in the pathogenesis of AD. Moreover, focusing on the NLRP3 inflammasome and combining with the upstream and downstream signaling pathway-related molecules of NLRP3 inflammasome as targets, we review the pharmacologically related targets and various methods to alleviate neuroinflammation by regulating the activation of NLRP3 inflammasome, which provides new ideas for the treatment of AD.
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Affiliation(s)
- Tao Liang
- Department of Clinical Laboratory, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Yang Zhang
- Department of Clinical Laboratory, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Suyuan Wu
- Department of Clinical Laboratory, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Qingjie Chen
- Hubei Key Laboratory of Diabetes and Angiopathy, Medicine Research Institute, Xianning Medical College, Hubei University of Science and Technology, Xianning, China
| | - Lin Wang
- Department of Clinical Laboratory, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
- Research Center for Tissue Engineering and Regenerative Medicine, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
- *Correspondence: Lin Wang,
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3
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Tran L, Kaffy J, Ongeri S, Ha-Duong T. Binding Modes of a Glycopeptidomimetic Molecule on Aβ Protofibrils: Implication for Its Inhibition Mechanism. ACS Chem Neurosci 2018; 9:2859-2869. [PMID: 30025208 DOI: 10.1021/acschemneuro.8b00341] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022] Open
Abstract
We recently reported that a glycopeptidomimetic molecule significantly delays the fibrillization process of Aβ42 peptide involved in Alzheimer's disease. However, the binding mode of this compound, named 3β, was not determined at the atomic scale, hindering our understanding of its mechanism of action and impeding structure-based design of new inhibitors. In the present study, we performed molecular docking calculations and molecular dynamics simulations to investigate the most probable structures of 3β complexed with Aβ protofibrils. Our results show that 3β preferentially binds to an area of the protofibril surface that coincides with the protofibril dimerization interface observed in the solid-state NMR structure 5KK3 from the PDB. Based on these observations, we propose a model of the inhibition mechanism of Aβ fibrillization by compound 3β.
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Affiliation(s)
- Linh Tran
- BioCIS, Université Paris-Sud, CNRS, Université Paris-Saclay, 92290 Châtenay-Malabry, France
| | - Julia Kaffy
- BioCIS, Université Paris-Sud, CNRS, Université Paris-Saclay, 92290 Châtenay-Malabry, France
| | - Sandrine Ongeri
- BioCIS, Université Paris-Sud, CNRS, Université Paris-Saclay, 92290 Châtenay-Malabry, France
| | - Tâp Ha-Duong
- BioCIS, Université Paris-Sud, CNRS, Université Paris-Saclay, 92290 Châtenay-Malabry, France
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4
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Zheng Q, Lazo ND. Mechanistic Studies of the Inhibition of Insulin Fibril Formation by Rosmarinic Acid. J Phys Chem B 2018; 122:2323-2331. [PMID: 29401384 DOI: 10.1021/acs.jpcb.8b00689] [Citation(s) in RCA: 35] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
The self-assembly of insulin to form amyloid fibrils has been widely studied because it is a significant problem in the medical management of diabetes and is an important model system for the investigation of amyloid formation and its inhibition. A few inhibitors of insulin fibrillation have been identified with potencies that could be higher. Knowledge of how these work at the molecular level is not known but important for the development of more potent inhibitors. Here we show that rosmarinic acid completely inhibits amyloid formation by dimeric insulin at pH 2 and 60 °C. In contrast to other polyphenols, rosmarinic acid is soluble in water and does not degrade at elevated temperatures, and thus we were able to decipher the mechanism of inhibition by a combination of solution-state 1H NMR spectroscopy and molecular docking. On the basis of 1H chemical shift perturbations, intermolecular nuclear Overhauser effect enhancements between rosmarinic acid and specific residues of insulin, and slowed dynamics of rosmarinic acid in the presence of insulin, we show that rosmarinic acid binds to a pocket found on the surface of each insulin monomer. This results in the formation of a mixed tetramolecular aromatic network on the surface of insulin dimer, resulting in increased resistance of the amyloidogenic protein to thermal unfolding. This finding opens new avenues for the design of potent inhibitors of amyloid formation and provides strong experimental evidence for the role of surface aromatic clusters in increasing the thermal stability of proteins.
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Affiliation(s)
- Qiuchen Zheng
- Carlson School of Chemistry and Biochemistry, Clark University , 950 Main Street, Worcester, Massachusetts 01610, United States
| | - Noel D Lazo
- Carlson School of Chemistry and Biochemistry, Clark University , 950 Main Street, Worcester, Massachusetts 01610, United States
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5
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Heller GT, Aprile FA, Vendruscolo M. Methods of probing the interactions between small molecules and disordered proteins. Cell Mol Life Sci 2017; 74:3225-3243. [PMID: 28631009 PMCID: PMC5533867 DOI: 10.1007/s00018-017-2563-4] [Citation(s) in RCA: 47] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2017] [Accepted: 06/01/2017] [Indexed: 12/15/2022]
Abstract
It is generally recognized that a large fraction of the human proteome is made up of proteins that remain disordered in their native states. Despite the fact that such proteins play key biological roles and are involved in many major human diseases, they still represent challenging targets for drug discovery. A major bottleneck for the identification of compounds capable of interacting with these proteins and modulating their disease-promoting behaviour is the development of effective techniques to probe such interactions. The difficulties in carrying out binding measurements have resulted in a poor understanding of the mechanisms underlying these interactions. In order to facilitate further methodological advances, here we review the most commonly used techniques to probe three types of interactions involving small molecules: (1) those that disrupt functional interactions between disordered proteins; (2) those that inhibit the aberrant aggregation of disordered proteins, and (3) those that lead to binding disordered proteins in their monomeric states. In discussing these techniques, we also point out directions for future developments.
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Affiliation(s)
- Gabriella T Heller
- Department of Chemistry, University of Cambridge, Cambridge, CB2 1EW, UK
| | - Francesco A Aprile
- Department of Chemistry, University of Cambridge, Cambridge, CB2 1EW, UK
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Yang W, Sabi-Mouka EMB, Wang L, Shu C, Wang Y, Ding J, Ding L. Determination of tranilast in bio-samples by LC-MS/MS: Application to a pharmacokinetic and brain tissue distribution study in rats. J Pharm Biomed Anal 2017; 147:479-484. [PMID: 28774678 DOI: 10.1016/j.jpba.2017.06.047] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2017] [Revised: 06/11/2017] [Accepted: 06/17/2017] [Indexed: 10/19/2022]
Abstract
As a potent drug used to improve the neurodegenerative conditions, there is few information about the brain tissue distribution of tranilast by now. In this study, a novel sensitive LC-MS/MS method has been developed and validated to determine tranilast in rat brain tissue samples. The calibration curve showed good linearity ranged from 2.140 to 428.0ng·mL-1. The method was fully validated and successfully applied in the brain tissue distribution study of tranilast in rats, which had never been reported in detail by now. Furthermore, a rapid LC-MS/MS method with a short run time of 3min was developed and validated for the determination of tranilast in rat plasma and the application to a pharmacokinetic study of tranilast in rats. After oral dosage of 10.5mg·kg-1 tranilast, the maximum plasma concentration (Cmax1) of tranilast was (18.59±5.40) μg·mL-1 at (0.667±0.408) h while the area under the curve (AUC0-24) was (54.87±14.13) μg·h·mL-1 with the elimination half-life of (2.93±0.41) h. The ratio calculated by dividing the concentration of tranilast in brain with the concentration of tranilast in the plasma, was (0.6042%±0.0572%), (0.7484%±0.0883%), (0.5914%±0.0416%) and (0.3830%±0.1632%) at 0.167, 0.5, 2 and 8h, respectively. The results showed that tranilast with fast absorption could penetrate the rat brain blood barrier after oral gavage. The obtained data also showed that tranilast could be quickly distributed and eliminated in brain tissue.
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Affiliation(s)
- Wen Yang
- Department of Pharmaceutical Analysis, China Pharmaceutical University, 24 Tongjiaxiang, Nanjing, 210009, China; Key Laboratory of Drug Quality Control and Pharmacovigilance, Ministry of Education, China Pharmaceutical University, 24 Tongjiaxiang, Nanjing, 210009, China
| | - Eboka Majolene B Sabi-Mouka
- Department of Pharmaceutical Analysis, China Pharmaceutical University, 24 Tongjiaxiang, Nanjing, 210009, China; Key Laboratory of Drug Quality Control and Pharmacovigilance, Ministry of Education, China Pharmaceutical University, 24 Tongjiaxiang, Nanjing, 210009, China
| | - Lei Wang
- Department of Pharmaceutical Analysis, China Pharmaceutical University, 24 Tongjiaxiang, Nanjing, 210009, China; Key Laboratory of Drug Quality Control and Pharmacovigilance, Ministry of Education, China Pharmaceutical University, 24 Tongjiaxiang, Nanjing, 210009, China
| | - Chang Shu
- Department of Pharmaceutical Analysis, China Pharmaceutical University, 24 Tongjiaxiang, Nanjing, 210009, China; Key Laboratory of Drug Quality Control and Pharmacovigilance, Ministry of Education, China Pharmaceutical University, 24 Tongjiaxiang, Nanjing, 210009, China
| | - Yan Wang
- Department of Pharmaceutical Analysis, China Pharmaceutical University, 24 Tongjiaxiang, Nanjing, 210009, China; Key Laboratory of Drug Quality Control and Pharmacovigilance, Ministry of Education, China Pharmaceutical University, 24 Tongjiaxiang, Nanjing, 210009, China; College of Pharmacy and Chemistry, Dali University, Wanhua Road, Dali 671000, China
| | - Juefang Ding
- Department of Pharmaceutical Analysis, China Pharmaceutical University, 24 Tongjiaxiang, Nanjing, 210009, China; Key Laboratory of Drug Quality Control and Pharmacovigilance, Ministry of Education, China Pharmaceutical University, 24 Tongjiaxiang, Nanjing, 210009, China; Nanjing Clinical Tech Laboratories Inc., 18 Zhilan Road, Jiangning District, Nanjing 211000, China
| | - Li Ding
- Department of Pharmaceutical Analysis, China Pharmaceutical University, 24 Tongjiaxiang, Nanjing, 210009, China; Key Laboratory of Drug Quality Control and Pharmacovigilance, Ministry of Education, China Pharmaceutical University, 24 Tongjiaxiang, Nanjing, 210009, China.
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7
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Cheng Q, Qiang W. Solid-State-NMR-Structure-Based Inhibitor Design to Achieve Selective Inhibition of the Parallel-in-Register β-Sheet versus Antiparallel Iowa Mutant β-Amyloid Fibrils. J Phys Chem B 2017; 121:5544-5552. [DOI: 10.1021/acs.jpcb.7b02953] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Affiliation(s)
- Qinghui Cheng
- Department of Chemistry, The State University of New York at Binghamton, Binghamton, New York 13902, United States
| | - Wei Qiang
- Department of Chemistry, The State University of New York at Binghamton, Binghamton, New York 13902, United States
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8
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Wu Y, Jiang C, Wu D, Gu Q, Luo ZY, Luo HB. Palladium-catalyzed C–H bond carboxylation of acetanilides: an efficient usage of N,N-dimethyloxamic acid as the carboxylate source. Chem Commun (Camb) 2016; 52:1286-9. [DOI: 10.1039/c5cc07890c] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
A palladium-catalyzed carboxylation of acetanilide and N,N-dimethyloxamic acid for the synthesis of N-acyl-anthranilic acids is described. N,N-Dimethyloxamic acid can act as an effective carboxylation precursor with K2S2O8 as the oxidant and Pd(OAc)2 as the catalyst.
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Affiliation(s)
- Yinuo Wu
- School of Pharmaceutical Sciences
- Sun Yat-sen University
- Guangzhou 510006
- China
| | - Cheng Jiang
- School of Pharmaceutical Sciences
- Sun Yat-sen University
- Guangzhou 510006
- China
| | - Deyan Wu
- School of Pharmaceutical Sciences
- Sun Yat-sen University
- Guangzhou 510006
- China
| | - Qiong Gu
- School of Pharmaceutical Sciences
- Sun Yat-sen University
- Guangzhou 510006
- China
| | - Zhang-Yi Luo
- School of Pharmaceutical Sciences
- Sun Yat-sen University
- Guangzhou 510006
- China
| | - Hai-Bin Luo
- School of Pharmaceutical Sciences
- Sun Yat-sen University
- Guangzhou 510006
- China
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9
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Nasica-Labouze J, Nguyen PH, Sterpone F, Berthoumieu O, Buchete NV, Coté S, De Simone A, Doig AJ, Faller P, Garcia A, Laio A, Li MS, Melchionna S, Mousseau N, Mu Y, Paravastu A, Pasquali S, Rosenman DJ, Strodel B, Tarus B, Viles JH, Zhang T, Wang C, Derreumaux P. Amyloid β Protein and Alzheimer's Disease: When Computer Simulations Complement Experimental Studies. Chem Rev 2015; 115:3518-63. [PMID: 25789869 DOI: 10.1021/cr500638n] [Citation(s) in RCA: 475] [Impact Index Per Article: 52.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Affiliation(s)
- Jessica Nasica-Labouze
- †Laboratoire de Biochimie Théorique, Institut de Biologie Physico-Chimique (IBPC), UPR9080 CNRS, Université Paris Diderot, Sorbonne Paris Cité, 13 rue Pierre et Marie Curie, 75005 Paris, France
| | - Phuong H Nguyen
- †Laboratoire de Biochimie Théorique, Institut de Biologie Physico-Chimique (IBPC), UPR9080 CNRS, Université Paris Diderot, Sorbonne Paris Cité, 13 rue Pierre et Marie Curie, 75005 Paris, France
| | - Fabio Sterpone
- †Laboratoire de Biochimie Théorique, Institut de Biologie Physico-Chimique (IBPC), UPR9080 CNRS, Université Paris Diderot, Sorbonne Paris Cité, 13 rue Pierre et Marie Curie, 75005 Paris, France
| | - Olivia Berthoumieu
- ‡LCC (Laboratoire de Chimie de Coordination), CNRS, Université de Toulouse, Université Paul Sabatier (UPS), Institut National Polytechnique de Toulouse (INPT), 205 route de Narbonne, BP 44099, Toulouse F-31077 Cedex 4, France
| | | | - Sébastien Coté
- ∥Département de Physique and Groupe de recherche sur les protéines membranaires (GEPROM), Université de Montréal, C.P. 6128, succursale Centre-ville, Montréal, Québec H3C 3T5, Canada
| | - Alfonso De Simone
- ⊥Department of Life Sciences, Imperial College London, London SW7 2AZ, United Kingdom
| | - Andrew J Doig
- #Manchester Institute of Biotechnology, University of Manchester, 131 Princess Street, Manchester M1 7DN, United Kingdom
| | - Peter Faller
- ‡LCC (Laboratoire de Chimie de Coordination), CNRS, Université de Toulouse, Université Paul Sabatier (UPS), Institut National Polytechnique de Toulouse (INPT), 205 route de Narbonne, BP 44099, Toulouse F-31077 Cedex 4, France
| | | | - Alessandro Laio
- ○The International School for Advanced Studies (SISSA), Via Bonomea 265, 34136 Trieste, Italy
| | - Mai Suan Li
- ◆Institute of Physics, Polish Academy of Sciences, Al. Lotnikow 32/46, 02-668 Warsaw, Poland.,¶Institute for Computational Science and Technology, SBI Building, Quang Trung Software City, Tan Chanh Hiep Ward, District 12, Ho Chi Minh City, Vietnam
| | - Simone Melchionna
- ⬠Instituto Processi Chimico-Fisici, CNR-IPCF, Consiglio Nazionale delle Ricerche, 00185 Roma, Italy
| | | | - Yuguang Mu
- ▲School of Biological Sciences, Nanyang Technological University, 60 Nanyang Drive, 637551 Singapore
| | - Anant Paravastu
- ⊕National High Magnetic Field Laboratory, 1800 East Paul Dirac Drive, Tallahassee, Florida 32310, United States
| | - Samuela Pasquali
- †Laboratoire de Biochimie Théorique, Institut de Biologie Physico-Chimique (IBPC), UPR9080 CNRS, Université Paris Diderot, Sorbonne Paris Cité, 13 rue Pierre et Marie Curie, 75005 Paris, France
| | | | - Birgit Strodel
- △Institute of Complex Systems: Structural Biochemistry (ICS-6), Forschungszentrum Jülich GmbH, 52425 Jülich, Germany
| | - Bogdan Tarus
- †Laboratoire de Biochimie Théorique, Institut de Biologie Physico-Chimique (IBPC), UPR9080 CNRS, Université Paris Diderot, Sorbonne Paris Cité, 13 rue Pierre et Marie Curie, 75005 Paris, France
| | - John H Viles
- ▼School of Biological and Chemical Sciences, Queen Mary University of London, London E1 4NS, United Kingdom
| | - Tong Zhang
- †Laboratoire de Biochimie Théorique, Institut de Biologie Physico-Chimique (IBPC), UPR9080 CNRS, Université Paris Diderot, Sorbonne Paris Cité, 13 rue Pierre et Marie Curie, 75005 Paris, France.,▲School of Biological Sciences, Nanyang Technological University, 60 Nanyang Drive, 637551 Singapore
| | | | - Philippe Derreumaux
- †Laboratoire de Biochimie Théorique, Institut de Biologie Physico-Chimique (IBPC), UPR9080 CNRS, Université Paris Diderot, Sorbonne Paris Cité, 13 rue Pierre et Marie Curie, 75005 Paris, France.,□Institut Universitaire de France, 75005 Paris, France
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10
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Hureau C, Faller P. Platinoid complexes to target monomeric disordered peptides: a forthcoming solution against amyloid diseases? Dalton Trans 2014; 43:4233-7. [DOI: 10.1039/c3dt52954a] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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11
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Rosenman DJ, Connors CR, Chen W, Wang C, García AE. Aβ monomers transiently sample oligomer and fibril-like configurations: ensemble characterization using a combined MD/NMR approach. J Mol Biol 2013; 425:3338-59. [PMID: 23811057 DOI: 10.1016/j.jmb.2013.06.021] [Citation(s) in RCA: 182] [Impact Index Per Article: 16.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2013] [Revised: 05/15/2013] [Accepted: 06/12/2013] [Indexed: 12/24/2022]
Abstract
Amyloid β (Aβ) peptides are a primary component of fibrils and oligomers implicated in the etiology of Alzheimer's disease (AD). However, the intrinsic flexibility of these peptides has frustrated efforts to investigate the secondary and tertiary structure of Aβ monomers, whose conformational landscapes directly contribute to the kinetics and thermodynamics of Aβ aggregation. In this work, de novo replica exchange molecular dynamics (REMD) simulations on the microseconds-per-replica timescale are used to characterize the structural ensembles of Aβ42, Aβ40, and M35-oxidized Aβ42, three physiologically relevant isoforms with substantially different aggregation properties. J-coupling data calculated from the REMD trajectories were compared to corresponding NMR-derived values acquired through two different pulse sequences, revealing that all simulations converge on the order of hundreds of nanoseconds-per-replica toward ensembles that yield good agreement with experiment. Though all three Aβ species adopt highly heterogeneous ensembles, these are considerably more structured compared to simulations on shorter timescales. Prominent in the C-terminus are antiparallel β-hairpins between L17-A21, A30-L36, and V39-I41, similar to oligomer and fibril intrapeptide models that expose these hydrophobic side chains to solvent and may serve as hotspots for self-association. Compared to reduced Aβ42, the absence of a second β-hairpin in Aβ40 and the sampling of alternate β topologies by M35-oxidized Aβ42 may explain the reduced aggregation rates of these forms. A persistent V24-K28 bend motif, observed in all three species, is stabilized by buried backbone to side-chain hydrogen bonds with D23 and a cross-region salt bridge between E22 and K28, highlighting the role of the familial AD-linked E22 and D23 residues in Aβ monomer folding. These characterizations help illustrate the conformational landscapes of Aβ monomers at atomic resolution and provide insight into the early stages of Aβ aggregation pathways.
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Affiliation(s)
- David J Rosenman
- Department of Biology, Rensselaer Polytechnic Institute, 110 8th Street, Troy, NY 12180, USA
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