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Jin Y, Downey MA, Singh A, Buratto SK, Bowers MT. Computationally Designed Small Molecules Disassemble Both Soluble Oligomers and Protofibrils of Amyloid β-Protein Responsible for Alzheimer's Disease. ACS Chem Neurosci 2023; 14:2717-2726. [PMID: 37442126 DOI: 10.1021/acschemneuro.3c00266] [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: 07/15/2023] Open
Abstract
Alzheimer's disease (AD) is one of the world's most pressing health crises. AD is an incurable disease affecting more than 6.5 million Americans, predominantly the elderly, and in its later stages, leads to memory loss, dementia, and death. Amyloid β (Aβ) protein aggregates have been one of the pathological hallmarks of AD since its initial characterization. The early stages of Aβ accumulation and aggregation involve the formation of oligomers, which are considered neurotoxic and play a key role in further aggregation into fibrils that eventually appear in the brain as amyloid plaques. We have recently shown by combining ion mobility mass spectrometry (IM-MS) and atomic force microscopy (AFM) that Aβ42 rapidly forms dodecamers (12-mers) as the terminal oligomeric state, and these dodecamers seed the early formation of Aβ42 protofibrils. The link between soluble oligomers and fibril formation is one of the essential aspects for understanding the root cause of the disease state and is critical to developing therapeutic interventions. Utilizing a joint pharmacophore space (JPS) method, potential drugs have been designed specifically for amyloid-related diseases. These small molecules were generated based on crucial chemical features necessary for target selectivity. In this paper, we utilize our combined IM-MS and AFM methods to investigate the impact of three second-generation JPS small-molecule inhibitors, AC0201, AC0202, and AC0203, on dodecamer as well as fibril formation in Aβ42. Our results indicate that AC0201 works well as an inhibitor and remodeler of both dodecamers and fibril formation, AC0203 behaves less efficiently, and AC0202 is ineffective.
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Affiliation(s)
- Yingying Jin
- Department of Chemistry and Biochemistry, University of California, Santa Barbara, California 93106, United States
| | - Matthew A Downey
- Department of Chemistry and Biochemistry, University of California, Santa Barbara, California 93106, United States
| | - Ambuj Singh
- Department of Computer Science, University of California, Santa Barbara, California 93106, United States
- Acelot, Inc., 3160 Porter Drive, Suite 200, Palo Alto, California 94304, United States
| | - Steven K Buratto
- Department of Chemistry and Biochemistry, University of California, Santa Barbara, California 93106, United States
| | - Michael T Bowers
- Department of Chemistry and Biochemistry, University of California, Santa Barbara, California 93106, United States
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Maina MB, Al-Hilaly YK, Serpell LC. Dityrosine cross-linking and its potential roles in Alzheimer's disease. Front Neurosci 2023; 17:1132670. [PMID: 37034163 PMCID: PMC10075315 DOI: 10.3389/fnins.2023.1132670] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/27/2022] [Accepted: 03/01/2023] [Indexed: 04/11/2023] Open
Abstract
Oxidative stress is a significant source of damage that accumulates during aging and contributes to Alzheimer's disease (AD) pathogenesis. Oxidation of proteins can give rise to covalent links between adjacent tyrosines known as dityrosine (DiY) cross-linking, amongst other modifications, and this observation suggests that DiY could serve as a biomarker of accumulated oxidative stress over the lifespan. Many studies have focused on understanding the contribution of DiY to AD pathogenesis and have revealed that DiY crosslinks can be found in both Aβ and tau deposits - the two key proteins involved in the formation of amyloid plaques and tau tangles, respectively. However, there is no consensus yet in the field on the impact of DiY on Aβ and tau function, aggregation, and toxicity. Here we review the current understanding of the role of DiY on Aβ and tau gathered over the last 20 years since the first observation, and discuss the effect of this modification for Aβ and tau aggregation, and its potential as a biomarker for AD.
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Affiliation(s)
- Mahmoud B. Maina
- Sussex Neuroscience, School of Life Sciences, University of Sussex, Falmer, United Kingdom
- Biomedical Science Research and Training Centre, College of Medical Sciences, Yobe State University, Damaturu, Nigeria
| | - Youssra K. Al-Hilaly
- Sussex Neuroscience, School of Life Sciences, University of Sussex, Falmer, United Kingdom
- Department of Chemistry, College of Science, Mustansiriyah University, Baghdad, Iraq
| | - Louise C. Serpell
- Sussex Neuroscience, School of Life Sciences, University of Sussex, Falmer, United Kingdom
- *Correspondence: Louise C. Serpell,
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Tzioras M, McGeachan RI, Durrant CS, Spires-Jones TL. Synaptic degeneration in Alzheimer disease. Nat Rev Neurol 2023; 19:19-38. [PMID: 36513730 DOI: 10.1038/s41582-022-00749-z] [Citation(s) in RCA: 90] [Impact Index Per Article: 90.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 11/04/2022] [Indexed: 12/15/2022]
Abstract
Alzheimer disease (AD) is characterized by progressive cognitive decline in older individuals accompanied by the presence of two pathological protein aggregates - amyloid-β and phosphorylated tau - in the brain. The disease results in brain atrophy caused by neuronal loss and synapse degeneration. Synaptic loss strongly correlates with cognitive decline in both humans and animal models of AD. Indeed, evidence suggests that soluble forms of amyloid-β and tau can cause synaptotoxicity and spread through neural circuits. These pathological changes are accompanied by an altered phenotype in the glial cells of the brain - one hypothesis is that glia excessively ingest synapses and modulate the trans-synaptic spread of pathology. To date, effective therapies for the treatment or prevention of AD are lacking, but understanding how synaptic degeneration occurs will be essential for the development of new interventions. Here, we highlight the mechanisms through which synapses degenerate in the AD brain, and discuss key questions that still need to be answered. We also cover the ways in which our understanding of the mechanisms of synaptic degeneration is leading to new therapeutic approaches for AD.
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Affiliation(s)
- Makis Tzioras
- Centre for Discovery Brain Sciences, The University of Edinburgh, Edinburgh, UK.,UK Dementia Research Institute, The University of Edinburgh, Edinburgh, UK
| | - Robert I McGeachan
- Centre for Discovery Brain Sciences, The University of Edinburgh, Edinburgh, UK.,UK Dementia Research Institute, The University of Edinburgh, Edinburgh, UK.,The Hospital for Small Animals, Royal (Dick) School of Veterinary Studies, The University of Edinburgh, Edinburgh, UK
| | - Claire S Durrant
- Centre for Discovery Brain Sciences, The University of Edinburgh, Edinburgh, UK.,UK Dementia Research Institute, The University of Edinburgh, Edinburgh, UK
| | - Tara L Spires-Jones
- Centre for Discovery Brain Sciences, The University of Edinburgh, Edinburgh, UK. .,UK Dementia Research Institute, The University of Edinburgh, Edinburgh, UK.
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Vanderlinden G, Ceccarini J, Vande Casteele T, Michiels L, Lemmens R, Triau E, Serdons K, Tournoy J, Koole M, Vandenbulcke M, Van Laere K. Spatial decrease of synaptic density in amnestic mild cognitive impairment follows the tau build-up pattern. Mol Psychiatry 2022; 27:4244-4251. [PMID: 35794185 DOI: 10.1038/s41380-022-01672-x] [Citation(s) in RCA: 15] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/17/2022] [Revised: 06/03/2022] [Accepted: 06/10/2022] [Indexed: 02/07/2023]
Abstract
Next to amyloid and tau, synaptic loss is a key pathological hallmark in Alzheimer's disease, closely related to cognitive dysfunction and neurodegeneration. Tau is thought to cause synaptic loss, but this has not been experimentally verified in vivo. In a 2-year follow-up study, dual tracer PET-MR was performed in 12 amnestic MCI patients using 18F-MK-6240 for tau and 11C-UCB-J for SV2A as a proxy for synaptic density. Tau already accumulated in the neocortex at baseline with progression in Braak V/VI at follow-up. While synaptic loss was limited to limbic regions at baseline, it followed the specific tau pattern to stage IV/V regions two years later, indicating that tau spread might drive synaptic vulnerability. Moreover, synaptic density changes correlated to changes in cognitive function. This study shows for the first time in vivo that synaptic loss regionally follows tau accumulation after two years, providing a disease-modifying window of opportunity for (combined) tau-targeting therapies.
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Affiliation(s)
- Greet Vanderlinden
- Nuclear Medicine and Molecular Imaging, Imaging Pathology, KU Leuven, Leuven, Belgium.
| | - Jenny Ceccarini
- Nuclear Medicine and Molecular Imaging, Imaging Pathology, KU Leuven, Leuven, Belgium
| | - Thomas Vande Casteele
- Neuropsychiatry, Department of Neurosciences, Leuven Brain Institute, KU Leuven, Leuven, Belgium
| | - Laura Michiels
- Department of Neurosciences, KU Leuven, Leuven, Belgium.,Department of Neurology, University Hospitals UZ Leuven, Leuven, Belgium.,VIB, Center for Brain & Disease Research, Laboratory of Neurobiology, Leuven, Belgium
| | - Robin Lemmens
- Department of Neurosciences, KU Leuven, Leuven, Belgium.,Department of Neurology, University Hospitals UZ Leuven, Leuven, Belgium.,VIB, Center for Brain & Disease Research, Laboratory of Neurobiology, Leuven, Belgium
| | - Eric Triau
- Private Practice Neurology, Leuven, Belgium
| | - Kim Serdons
- Department of Nuclear Medicine, University Hospitals UZ Leuven, Leuven, Belgium
| | - Jos Tournoy
- Department of Geriatric Medicine, University Hospitals UZ Leuven, Leuven, Belgium.,Department of Public Health and Primary Care, Gerontology and Geriatrics, KU Leuven, Leuven, Belgium
| | - Michel Koole
- Nuclear Medicine and Molecular Imaging, Imaging Pathology, KU Leuven, Leuven, Belgium
| | - Mathieu Vandenbulcke
- Neuropsychiatry, Department of Neurosciences, Leuven Brain Institute, KU Leuven, Leuven, Belgium.,Department of Old-Age Psychiatry, University Hospitals UZ Leuven, Leuven, Belgium
| | - Koen Van Laere
- Nuclear Medicine and Molecular Imaging, Imaging Pathology, KU Leuven, Leuven, Belgium.,Department of Nuclear Medicine, University Hospitals UZ Leuven, Leuven, Belgium
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Post-Synapses in the Brain: Role of Dendritic and Spine Structures. Biomedicines 2022; 10:biomedicines10081859. [PMID: 36009405 PMCID: PMC9405724 DOI: 10.3390/biomedicines10081859] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2022] [Revised: 06/26/2022] [Accepted: 07/22/2022] [Indexed: 02/07/2023] Open
Abstract
Brain synapses are neuronal structures of the greatest interest. For a long time, however, the knowledge about them was variable, and interest was mostly focused on their pre-synaptic portions, especially neurotransmitter release from axon terminals. In the present review interest is focused on post-synapses, the structures receiving and converting pre-synaptic messages. Upon further modulation, such messages are transferred to dendritic fibers. Dendrites are profoundly different from axons; they are shorter and of variable thickness. Their post-synapses are of two types. Those called flat/intended/aspines, integrated into dendritic fibers, are very frequent in inhibitory neurons. The spines, small and stemming protrusions, connected to dendritic fibers by their necks, are present in almost all excitatory neurons. Several structures and functions including the post-synaptic densities and associated proteins, the nanoscale mechanisms of compartmentalization, the cytoskeletons of actin and microtubules, are analogous in the two post-synaptic forms. However other properties, such as plasticity and its functions of learning and memory, are largely distinct. Several properties of spines, including emersion from dendritic fibers, growth, change in shape and decreases in size up to disappearance, are specific. Spinal heads correspond to largely independent signaling compartments. They are motile, their local signaling is fast, however transport through their thin necks is slow. When single spines are activated separately, their dendritic effects are often lacking; when multiple spines are activated concomitantly, their effects take place. Defects of post-synaptic responses, especially those of spines, take place in various brain diseases. Here alterations affecting symptoms and future therapy are shown to occur in neurodegenerative diseases and autism spectrum disorders.
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