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Salaikumaran M, Gopal PP. Rational Design of TDP-43 Derived α-Helical Peptide Inhibitors: An In Silico Strategy to Prevent TDP-43 Aggregation in Neurodegenerative Disorders. ACS Chem Neurosci 2024; 15:1096-1109. [PMID: 38466778 PMCID: PMC10959110 DOI: 10.1021/acschemneuro.3c00659] [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: 10/12/2023] [Revised: 01/21/2024] [Accepted: 02/19/2024] [Indexed: 03/13/2024] Open
Abstract
TDP-43, an essential RNA/DNA-binding protein, is central to the pathology of neurodegenerative diseases, such as amyotrophic lateral sclerosis and frontotemporal dementia. Pathological mislocalization and aggregation of TDP-43 disrupt RNA splicing, mRNA stability, and mRNA transport, thereby impairing neuronal function and survival. The formation of amyloid-like TDP-43 filaments is largely facilitated by the destabilization of an α-helical segment within the disordered C-terminal region. In this study, we hypothesized that preventing the destabilization of the α-helical domain could potentially halt the growth of these pathological filaments. To explore this, we utilized a range of in silico techniques to design and evaluate peptide-based therapeutics that bind to pathological TDP-43 amyloid-like filament crystal structures and resist β sheet conversion. Our computational approaches, including biophysical and secondary structure property prediction, molecular docking, 3D structure prediction, and molecular dynamics simulations, were used to assess the structure, stability, and binding affinity of these peptides in relation to pathological TDP-43 filaments. The results of our in silico analyses identified a selection of promising peptides which displayed a stable α-helical structure, exhibited an increased number of intramolecular hydrogen bonds within the helical domain, and demonstrated high binding affinities for pathological TDP-43 amyloid-like filaments. Molecular dynamics simulations provided further support for the structural and thermodynamic stability of these peptides, as they exhibited lower root-mean-square deviation and more favorable free energy landscapes over 300 ns. These findings establish α-helical propensity peptides as potential lead molecules for the development of novel therapeutics against TDP-43 aggregation. This structure-based computational approach for the rational design of peptide inhibitors opens a new direction in the search for effective interventions for ALS, FTD, and other related neurodegenerative diseases. The peptides identified as the most promising candidates in this study are currently subject to further testing and validation through both in vitro and in vivo experiments.
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Affiliation(s)
- Muthu
Raj Salaikumaran
- Department
of Pathology, Yale School of Medicine, New Haven, Connecticut 06520, United States
| | - Pallavi P. Gopal
- Department
of Pathology, Yale School of Medicine, New Haven, Connecticut 06520, United States
- Program
in Cellular Neuroscience, Neurodegeneration, and Repair, Yale School of Medicine, New Haven, Connecticut 06520-8055, United States
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Pretti E, Shell MS. Mapping the configurational landscape and aggregation phase behavior of the tau protein fragment PHF6. Proc Natl Acad Sci U S A 2023; 120:e2309995120. [PMID: 37983502 PMCID: PMC10691331 DOI: 10.1073/pnas.2309995120] [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: 06/13/2023] [Accepted: 10/17/2023] [Indexed: 11/22/2023] Open
Abstract
The PHF6 (Val-Gln-Ile-Val-Tyr-Lys) motif, found in all isoforms of the microtubule-associated protein tau, forms an integral part of ordered cores of amyloid fibrils formed in tauopathies and is thought to play a fundamental role in tau aggregation. Because PHF6 as an isolated hexapeptide assembles into ordered fibrils on its own, it is investigated as a minimal model for insight into the initial stages of aggregation of larger tau fragments. Even for this small peptide, however, the large length and time scales associated with fibrillization pose challenges for simulation studies of its dynamic assembly, equilibrium configurational landscape, and phase behavior. Here, we develop an accurate, bottom-up coarse-grained model of PHF6 for large-scale simulations of its aggregation, which we use to uncover molecular interactions and thermodynamic driving forces governing its assembly. The model, not trained on any explicit information about fibrillar structure, predicts coexistence of formed fibrils with monomers in solution, and we calculate a putative equilibrium phase diagram in concentration-temperature space. We also characterize the configurational and free energetic landscape of PHF6 oligomers. Importantly, we demonstrate with a model of heparin that this widely studied cofactor enhances the aggregation propensity of PHF6 by ordering monomers during nucleation and remaining associated with growing fibrils, consistent with experimentally characterized heparin-tau interactions. Overall, this effort provides detailed molecular insight into PHF6 aggregation thermodynamics and pathways and, furthermore, demonstrates the potential of modern multiscale modeling techniques to produce predictive models of amyloidogenic peptides simultaneously capturing sequence-specific effects and emergent aggregate structures.
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Affiliation(s)
- Evan Pretti
- Department of Chemical Engineering, University of California, Santa Barbara, CA93106-5080
| | - M. Scott Shell
- Department of Chemical Engineering, University of California, Santa Barbara, CA93106-5080
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Jana AK, Güven Ö, Yaşar F. The stability and dynamics of the Aβ40/Aβ42 interlaced mixed fibrils. J Biomol Struct Dyn 2023:1-14. [PMID: 37964619 DOI: 10.1080/07391102.2023.2280765] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2023] [Accepted: 11/01/2023] [Indexed: 11/16/2023]
Abstract
The accumulation of fibrillar amyloid-β (Aβ) aggregates in the brain, predominantly comprising 40- and 42-residue amyloid-β (Aβ40 and Aβ42), is a major pathological hallmark of Alzheimer's disease (AD). Aβ40 and Aβ42 naturally coexist in the brain under normal physiological conditions, and their interplay is generally considered to be a critical factor in the progression of AD. In addition to forming homogeneous oligomers and fibrils, Aβ40 and Aβ42 are also reported to co-assemble into hetero-oligomers and interlaced mixed fibrils, as evidenced by solid-state nuclear magnetic resonance spectroscopy (NMR), high molecular weight mass spectrometry and cross-seeding experiments. However, the exact molecular mechanisms underlying these processes remain unclear. In this study, we have used a recently resolved structurally uniform 1:1 mixture of Aβ40/Aβ42 interlaced mixed fibril as a prototype to gain insights into the molecular-level interactions between Aβ40 and Aβ42. We employed fully atomistic molecular dynamics simulation and compared the results with a homogeneous U-shaped Aβ40 fibrillar model. Our simulations using two different force fields provide conclusive evidence that the Aβ40/Aβ42 interlaced mixed fibril is energetically more favorable than the homogeneous Aβ40 fibrillar model. Furthermore, we also show that the increase in stability observed in the mixed model stems primarily from the packing interfaces and the stacking interfaces between C-termini. Our simulation results provide valuable mechanistic insights that are not readily accessible in experiment and could have significant implications for both the pathogenesis of AD and the development of current therapeutic strategies.Communicated by Ramaswamy H. Sarma.
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Affiliation(s)
- Asis K Jana
- Department of Microbiology and Biotechnology, Sister Nivedita University, Kolkata, West Bengal, India
| | - Özgür Güven
- Department of Physics Engineering, Hacettepe University, Ankara, Türkiye
| | - Fatih Yaşar
- Department of Physics Engineering, Hacettepe University, Ankara, Türkiye
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Man VH, He X, Han F, Cai L, Wang L, Niu T, Zhai J, Ji B, Gao J, Wang J. Phosphorylation at Ser289 Enhances the Oligomerization of Tau Repeat R2. J Chem Inf Model 2023; 63:1351-1361. [PMID: 36786552 PMCID: PMC10032562 DOI: 10.1021/acs.jcim.2c01597] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2022] [Indexed: 02/15/2023]
Abstract
In tauopathies such as Alzheimer's disease (AD), aberrant phosphorylation causes the dissociation of tau proteins from microtubules. The dissociated tau then aggregates into sequent forms from soluble oligomers to paired helical filaments and insoluble neurofibrillary tangles (NFTs). NFTs is a hallmark of AD, while oligomers are found to be the most toxic form of the tau aggregates. Therefore, understanding tau oligomerization with regard to abnormal phosphorylation is important for the therapeutic development of AD. In this study, we investigated the impact of phosphorylated Ser289, one of the 40 aberrant phosphorylation sites of full-length tau proteins, on monomeric and dimeric structures of tau repeat R2 peptides. We carried out intensive replica exchange molecular dynamics simulation with a total simulation time of up to 0.1 ms. Our result showed that the phosphorylation significantly affected the structures of both the monomer and the dimer. For the monomer, the phosphorylation enhanced ordered-disordered structural transition and intramolecular interaction, leading to more compactness of the phosphorylated R2 compared to the wild-type one. As to the dimer, the phosphorylation increased intermolecular interaction and β-sheet formation, which can accelerate the oligomerization of R2 peptides. This result suggests that the phosphorylation at Ser289 is likely to promote tau aggregation. We also observed a phosphorylated Ser289-Na+-phosphorylated Ser289 bridge in the phosphorylated R2 dimer, suggesting an important role of cation ions in tau aggregation. Our findings suggest that phosphorylation at Ser289 should be taken into account in the inhibitor screening of tau oligomerization.
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Affiliation(s)
- Viet Hoang Man
- Department
of Pharmaceutical Sciences and Computational Chemical Genomics Screening
Center, School of Pharmacy, University of
Pittsburgh, Pittsburgh, Pennsylvania 15261, United States
| | - Xibing He
- Department
of Pharmaceutical Sciences and Computational Chemical Genomics Screening
Center, School of Pharmacy, University of
Pittsburgh, Pittsburgh, Pennsylvania 15261, United States
| | - Fengyang Han
- Department
of Pharmaceutical Sciences and Computational Chemical Genomics Screening
Center, School of Pharmacy, University of
Pittsburgh, Pittsburgh, Pennsylvania 15261, United States
| | - Lianjin Cai
- Department
of Pharmaceutical Sciences and Computational Chemical Genomics Screening
Center, School of Pharmacy, University of
Pittsburgh, Pittsburgh, Pennsylvania 15261, United States
| | - Luxuan Wang
- Department
of Pharmaceutical Sciences and Computational Chemical Genomics Screening
Center, School of Pharmacy, University of
Pittsburgh, Pittsburgh, Pennsylvania 15261, United States
| | - Taoyu Niu
- Department
of Pharmaceutical Sciences and Computational Chemical Genomics Screening
Center, School of Pharmacy, University of
Pittsburgh, Pittsburgh, Pennsylvania 15261, United States
| | - Jingchen Zhai
- Department
of Pharmaceutical Sciences and Computational Chemical Genomics Screening
Center, School of Pharmacy, University of
Pittsburgh, Pittsburgh, Pennsylvania 15261, United States
| | - Beihong Ji
- Department
of Pharmaceutical Sciences and Computational Chemical Genomics Screening
Center, School of Pharmacy, University of
Pittsburgh, Pittsburgh, Pennsylvania 15261, United States
| | - Jie Gao
- Department
of Neuroscience, The Ohio State University
Wexner Medical Center, Columbus, Ohio 43210, United States
| | - Junmei Wang
- Department
of Pharmaceutical Sciences and Computational Chemical Genomics Screening
Center, School of Pharmacy, University of
Pittsburgh, Pittsburgh, Pennsylvania 15261, United States
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Zou Y, Guan L, Tan J, Qi B, Wang Y, Zhang Q, Sun Y. Atomistic Insights into the Inhibitory Mechanism of Tyrosine Phosphorylation against the Aggregation of Human Tau Fragment PHF6. J Phys Chem B 2023; 127:335-345. [PMID: 36594671 DOI: 10.1021/acs.jpcb.2c07568] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
Abnormal aggregation of the microtubule-associated protein tau into intracellular fibrillary inclusions is characterized as the hallmark of tauopathies, including Alzheimer's disease and chronic traumatic encephalopathy. The hexapeptide 306VQIVYK311 (PHF6) of R3 plays an important role in the aggregation of tau. Recent experimental studies reported that phosphorylation of residue tyrosine 310 (Y310) could decrease the propensity of PHF6 to form fibrils and inhibit tau aggregation. However, the underlying inhibitory mechanism is not well understood. In this work, we systematically investigated the influences of phosphorylation on the conformational ensembles and oligomerization dynamics of PHF6 by performing extensive all-atom molecular dynamics (MD) simulations. Our replica exchange MD simulations demonstrate that Y310 phosphorylation could effectively suppress the formation of β-structure and shift PHF6 oligomers toward coil-rich aggregates. The interaction analyses show that hydrogen bonding and hydrophobic interactions among PHF6 peptides, as well as Y310-Y310 π-π stacking and I308-Y310 CH-π interactions, are weakened by phosphorylation. Additional microsecond MD simulations show that Y310 phosphorylation could inhibit the oligomerization of PHF6 by preventing the formation of large β-sheet oligomers and multi-layer β-sheet aggregates. This study provides mechanistic insights into the phosphorylation-inhibited tau aggregation, which may be helpful for the in-depth understanding of the pathogenesis of tauopathies.
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Affiliation(s)
- Yu Zou
- Department of Sport and Exercise Science, College of Education, Zhejiang University, 886 Yuhangtang Road, Hangzhou, Zhejiang 310058, People's Republic of China
| | - Lulu Guan
- Department of Sport and Exercise Science, College of Education, Zhejiang University, 886 Yuhangtang Road, Hangzhou, Zhejiang 310058, People's Republic of China
| | - Jingwang Tan
- Department of Sport and Exercise Science, College of Education, Zhejiang University, 886 Yuhangtang Road, Hangzhou, Zhejiang 310058, People's Republic of China
| | - Bote Qi
- Department of Sport and Exercise Science, College of Education, Zhejiang University, 886 Yuhangtang Road, Hangzhou, Zhejiang 310058, People's Republic of China
| | - Ying Wang
- Department of Physics, Ningbo University, 818 Fenghua Road, Ningbo, Zhejiang 315211, People's Republic of China
| | - Qingwen Zhang
- College of Physical Education and Training, Shanghai University of Sport, 399 Changhai Road, Shanghai 200438, People's Republic of China
| | - Yunxiang Sun
- Department of Physics, Ningbo University, 818 Fenghua Road, Ningbo, Zhejiang 315211, People's Republic of China
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Tang Y, Zhang D, Gong X, Zheng J. A mechanistic survey of Alzheimer's disease. Biophys Chem 2021; 281:106735. [PMID: 34894476 DOI: 10.1016/j.bpc.2021.106735] [Citation(s) in RCA: 29] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2021] [Revised: 11/26/2021] [Accepted: 11/26/2021] [Indexed: 02/06/2023]
Abstract
Alzheimer's disease (AD) is the most common, age-dependent neurodegenerative disorder. While AD has been intensively studied from different aspects, there is no effective cure for AD, largely due to a lack of a clear mechanistic understanding of AD. In this mini-review, we mainly focus on the discussion and summary of mechanistic causes of Alzheimer's disease (AD). While different AD mechanisms illustrate different molecular and cellular pathways in AD pathogenesis, they do not necessarily exclude each other. Instead, some of them could work together to initiate, trigger, and promote the onset and development of AD. In a broader viewpoint, some AD mechanisms (e.g., amyloid aggregation mechanism, microbial infection/neuroinflammation mechanism, and amyloid cross-seeding mechanism) could also be applicable to other amyloid diseases including type II diabetes, Parkinson's disease, and prion disease. Such common mechanisms for AD and other amyloid diseases explain not only the pathogenesis of individual amyloid diseases, but also the spreading of pathologies between these diseases, which will inspire new strategies for therapeutic intervention and prevention for AD.
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Affiliation(s)
- Yijing Tang
- Department of Chemical, Biomolecular, and Corrosion Engineering, The University of Akron, OH, United States of America
| | - Dong Zhang
- Department of Chemical, Biomolecular, and Corrosion Engineering, The University of Akron, OH, United States of America
| | - Xiong Gong
- Department of Polymer Engineering, The University of Akron, OH, United States of America
| | - Jie Zheng
- Department of Chemical, Biomolecular, and Corrosion Engineering, The University of Akron, OH, United States of America.
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