1
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Li M, Yu Q, Anayyat U, Yang H, Wei Y, Wang X. Rotating magnetic field improved cognitive and memory impairments in a sporadic ad model of mice by regulating microglial polarization. GeroScience 2024:10.1007/s11357-024-01223-y. [PMID: 38904930 DOI: 10.1007/s11357-024-01223-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2023] [Accepted: 05/24/2024] [Indexed: 06/22/2024] Open
Abstract
Neuroinflammation, triggered by aberrantly activated microglia, is widely recognized as a key contributor to the initiation and progression of Alzheimer's disease (AD). Microglial activation in the central nervous system (CNS) can be classified into two distinct phenotypes: the pro-inflammatory M1 phenotype and the anti-inflammatory M2 phenotype. In this study, we investigated the effects of a non-invasive rotating magnetic field (RMF) (0.2T, 4Hz) on cognitive and memory impairments in a sporadic AD model of female Kunming mice induced by AlCl3 and D-gal. Our findings revealed significant improvements in cognitive and memory impairments following RMF treatment. Furthermore, RMF treatment led to reduced amyloid-beta (Aβ) deposition, mitigated damage to hippocampal morphology, prevented synaptic and neuronal loss, and alleviated cell apoptosis in the hippocampus and cortex of AD mice. Notably, RMF treatment ameliorated neuroinflammation, facilitated the transition of microglial polarization from M1 to M2, and inhibited the NF-кB/MAPK pathway. Additionally, RMF treatment resulted in reduced aluminum deposition in the brains of AD mice. In cellular experiments, RMF promoted the M1-M2 polarization transition and enhanced amyloid phagocytosis in cultured BV2 cells while inhibiting the TLR4/NF-кB/MAPK pathway. Collectively, these results demonstrate that RMF improves memory and cognitive impairments in a sporadic AD model, potentially by promoting the M1 to M2 transition of microglial polarization through inhibition of the NF-кB/MAPK signaling pathway. These findings suggest the promising therapeutic applications of RMF in the clinical treatment of AD.
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Affiliation(s)
- Mengqing Li
- Shenzhen University School of Basic Medical Sciences, Shenzhen, 518055, Guangdong, China
| | - Qinyao Yu
- Shenzhen University College of Medicine, Shenzhen, 518055, Guangdong, China
| | - Umer Anayyat
- Shenzhen University School of Basic Medical Sciences, Shenzhen, 518055, Guangdong, China
| | - Hua Yang
- Shenzhen University School of Basic Medical Sciences, Shenzhen, 518055, Guangdong, China
| | - Yunpeng Wei
- Shenzhen University School of Basic Medical Sciences, Shenzhen, 518055, Guangdong, China.
| | - Xiaomei Wang
- Shenzhen University School of Basic Medical Sciences, Shenzhen, 518055, Guangdong, China.
- Shenzhen University International Cancer Center, Shenzhen, 518055, Guangdong, China.
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2
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Marshall KE, Mengham K, Spink MC, Vania L, Pollard HJ, Darrow MC, Duke E, Harkiolaki M, Serpell LC. Correlative cryo-soft X-ray tomography and cryo-structured illumination microscopy reveal changes to lysosomes in amyloid-β-treated neurons. Structure 2024; 32:585-593.e3. [PMID: 38471506 DOI: 10.1016/j.str.2024.02.010] [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] [Received: 10/10/2023] [Revised: 12/20/2023] [Accepted: 02/15/2024] [Indexed: 03/14/2024]
Abstract
Protein misfolding is common to neurodegenerative diseases (NDs) including Alzheimer's disease (AD), which is partly characterized by the self-assembly and accumulation of amyloid-beta in the brain. Lysosomes are a critical component of the proteostasis network required to degrade and recycle material from outside and within the cell and impaired proteostatic mechanisms have been implicated in NDs. We have previously established that toxic amyloid-beta oligomers are endocytosed, accumulate in lysosomes, and disrupt the endo-lysosomal system in neurons. Here, we use pioneering correlative cryo-structured illumination microscopy and cryo-soft X-ray tomography imaging techniques to reconstruct 3D cellular architecture in the native state revealing reduced X-ray density in lysosomes and increased carbon dense vesicles in oligomer treated neurons compared with untreated cells. This work provides unprecedented visual information on the changes to neuronal lysosomes inflicted by amyloid beta oligomers using advanced methods in structural cell biology.
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Affiliation(s)
- Karen E Marshall
- Sussex Neuroscience, School of Life Sciences, University of Sussex, Falmer, BN1 9QG Brighton, UK.
| | - Kurtis Mengham
- Sussex Neuroscience, School of Life Sciences, University of Sussex, Falmer, BN1 9QG Brighton, UK
| | - Matthew C Spink
- Diamond Light Source, Diamond House, Harwell Science and Innovation Campus, Fermi Avenue, OX11 0DE Didcot, UK
| | - Lyra Vania
- Sussex Neuroscience, School of Life Sciences, University of Sussex, Falmer, BN1 9QG Brighton, UK
| | - Hannah Jane Pollard
- Sussex Neuroscience, School of Life Sciences, University of Sussex, Falmer, BN1 9QG Brighton, UK
| | - Michele C Darrow
- Diamond Light Source, Diamond House, Harwell Science and Innovation Campus, Fermi Avenue, OX11 0DE Didcot, UK
| | - Elizabeth Duke
- Diamond Light Source, Diamond House, Harwell Science and Innovation Campus, Fermi Avenue, OX11 0DE Didcot, UK
| | - Maria Harkiolaki
- Diamond Light Source, Diamond House, Harwell Science and Innovation Campus, Fermi Avenue, OX11 0DE Didcot, UK
| | - Louise C Serpell
- Sussex Neuroscience, School of Life Sciences, University of Sussex, Falmer, BN1 9QG Brighton, UK.
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3
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Xu Z, Hu J, Wei Z, Lei Y, Afewerky HK, Gao Y, Wan L, Li L, Lei L, Liu Y, Huang F, Yu T, Wang J, Li H, Liu R, Wang X. Dynamic changes in lysosome-related pathways in APP/PS1 mice with aging. MedComm (Beijing) 2024; 5:e540. [PMID: 38606360 PMCID: PMC11006716 DOI: 10.1002/mco2.540] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2023] [Revised: 03/15/2024] [Accepted: 03/16/2024] [Indexed: 04/13/2024] Open
Abstract
Senile plaque, composed of amyloid β protein (Aβ) aggregates, is a critical pathological feature in Alzheimer's disease (AD), leading to cognitive dysfunction. However, how Aβ aggregates exert age-dependent toxicity and temporal cognitive dysfunction in APP/PS1 mice remains incompletely understood. In this study, we investigated AD pathogenesis and dynamic alterations in lysosomal pathways within the hippocampus of age-gradient male mice using transcriptome sequencing, molecular biology assays, and histopathological analyses. We observed high levels of β-amyloid precursor protein (APP) protein expression in the hippocampus at an early stage and age-dependent Aβ deposition. Transcriptome sequencing revealed the enrichment of differential genes related to the lysosome pathway. Furthermore, the protein expression of ATP6V0d2 and CTSD associated with lysosomal functions exhibited dynamic changes with age, increasing in the early stage and decreasing later. Similar age-dependent patterns were observed for the endosome function, autophagy pathway, and SGK1/FOXO3a pathway. Nissl and Golgi staining in the hippocampal region showed age-dependent neuronal loss and synaptic damage, respectively. These findings clearly define the age-gradient changes in the autophagy-lysosome system, the endosome/lysosome system, and the SGK1/FOXO3a pathway in the hippocampus of APP/PS1 mice, providing new perspectives and clues for understanding the possible mechanisms of AD, especially the transition from compensatory to decompensated state.
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Affiliation(s)
- Zhendong Xu
- Department of PathophysiologySchool of Basic MedicineKey Laboratory of Education Ministry/Hubei Province of China for Neurological DisordersTongji Medical College, Huazhong University of Science and TechnologyWuhanChina
| | - Jichang Hu
- Department of PathophysiologySchool of Basic MedicineKey Laboratory of Education Ministry/Hubei Province of China for Neurological DisordersTongji Medical College, Huazhong University of Science and TechnologyWuhanChina
| | - Zhen Wei
- Department of PathophysiologySchool of Basic MedicineKey Laboratory of Education Ministry/Hubei Province of China for Neurological DisordersTongji Medical College, Huazhong University of Science and TechnologyWuhanChina
| | - Yu Lei
- Department of PathophysiologySchool of Basic MedicineKey Laboratory of Education Ministry/Hubei Province of China for Neurological DisordersTongji Medical College, Huazhong University of Science and TechnologyWuhanChina
| | - Henok Kessete Afewerky
- Department of PathophysiologySchool of Basic MedicineKey Laboratory of Education Ministry/Hubei Province of China for Neurological DisordersTongji Medical College, Huazhong University of Science and TechnologyWuhanChina
| | - Yang Gao
- Department of PathophysiologySchool of Basic MedicineKey Laboratory of Education Ministry/Hubei Province of China for Neurological DisordersTongji Medical College, Huazhong University of Science and TechnologyWuhanChina
| | - Lu Wan
- Department of PathophysiologySchool of Basic MedicineKey Laboratory of Education Ministry/Hubei Province of China for Neurological DisordersTongji Medical College, Huazhong University of Science and TechnologyWuhanChina
| | - Longfei Li
- Department of PathophysiologySchool of Basic MedicineKey Laboratory of Education Ministry/Hubei Province of China for Neurological DisordersTongji Medical College, Huazhong University of Science and TechnologyWuhanChina
| | - Ling Lei
- Department of PathophysiologySchool of Basic MedicineKey Laboratory of Education Ministry/Hubei Province of China for Neurological DisordersTongji Medical College, Huazhong University of Science and TechnologyWuhanChina
| | - Yi Liu
- Department of PathophysiologySchool of Basic MedicineKey Laboratory of Education Ministry/Hubei Province of China for Neurological DisordersTongji Medical College, Huazhong University of Science and TechnologyWuhanChina
| | - Fang Huang
- Department of PathophysiologySchool of Basic MedicineKey Laboratory of Education Ministry/Hubei Province of China for Neurological DisordersTongji Medical College, Huazhong University of Science and TechnologyWuhanChina
| | - Tong Yu
- Department of PathophysiologySchool of Basic MedicineKey Laboratory of Education Ministry/Hubei Province of China for Neurological DisordersTongji Medical College, Huazhong University of Science and TechnologyWuhanChina
| | - Jian‐Zhi Wang
- Department of PathophysiologySchool of Basic MedicineKey Laboratory of Education Ministry/Hubei Province of China for Neurological DisordersTongji Medical College, Huazhong University of Science and TechnologyWuhanChina
- Co‐innovation Center of NeuroregenerationNantong UniversityNantongChina
| | - Hong‐Lian Li
- Department of PathophysiologySchool of Basic MedicineKey Laboratory of Education Ministry/Hubei Province of China for Neurological DisordersTongji Medical College, Huazhong University of Science and TechnologyWuhanChina
| | - Rong Liu
- Department of PathophysiologySchool of Basic MedicineKey Laboratory of Education Ministry/Hubei Province of China for Neurological DisordersTongji Medical College, Huazhong University of Science and TechnologyWuhanChina
| | - Xiaochuan Wang
- Department of PathophysiologySchool of Basic MedicineKey Laboratory of Education Ministry/Hubei Province of China for Neurological DisordersTongji Medical College, Huazhong University of Science and TechnologyWuhanChina
- Co‐innovation Center of NeuroregenerationNantong UniversityNantongChina
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4
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Zhu WH, Yang XX, Gou XZ, Fu SM, Chen JH, Gao F, Shen Y, Bi DL, Tang AH. Nanoscale reorganisation of synaptic proteins in Alzheimer's disease. Neuropathol Appl Neurobiol 2023; 49:e12924. [PMID: 37461203 DOI: 10.1111/nan.12924] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2022] [Revised: 05/30/2023] [Accepted: 06/24/2023] [Indexed: 08/31/2023]
Abstract
AIMS Synaptic strength depends strongly on the subsynaptic organisation of presynaptic transmitter release and postsynaptic receptor densities, and their alterations are expected to underlie pathologies. Although synaptic dysfunctions are common pathogenic traits of Alzheimer's disease (AD), it remains unknown whether synaptic protein nano-organisation is altered in AD. Here, we systematically characterised the alterations in the subsynaptic organisation in cellular and mouse models of AD. METHODS We used immunostaining and super-resolution stochastic optical reconstruction microscopy imaging to quantitatively examine the synaptic protein nano-organisation in both Aβ1-42-treated neuronal cultures and cortical sections from a mouse model of AD, APP23 mice. RESULTS We found that Aβ1-42-treatment of cultured hippocampal neurons decreased the synaptic retention of postsynaptic scaffolds and receptors and disrupted their nanoscale alignment to presynaptic transmitter release sites. In cortical sections, we found that while GluA1 receptors in wild-type mice were organised in subsynaptic nanoclusters with high local densities, receptors in APP23 mice distributed more homogeneously within synapses. This reorganisation, together with the reduced overall receptor density, led to reduced glutamatergic synaptic transmission. Meanwhile, the transsynaptic alignment between presynaptic release-guiding RIM1/2 and postsynaptic scaffolding protein PSD-95 was reduced in APP23 mice. Importantly, these reorganisations were progressive with age and were more pronounced in synapses in close vicinity of Aβ plaques with dense cores. CONCLUSIONS Our study revealed a spatiotemporal-specific reorganisation of synaptic nanostructures in AD and identifies dense-core amyloid plaques as the major local inductor in APP23 mice.
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Affiliation(s)
- Wang-Hui Zhu
- Hefei National Research Center for Physical Sciences at the Microscale, CAS Key Laboratory of Brain Function and Disease, Ministry of Education Key Laboratory for Membrane-less Organelles and Cellular Dynamics, Division of Life Sciences and Medicine, University of Science and Technology of China, Hefei, China
- Institute of Artificial Intelligence, Hefei Comprehensive National Science Center, Hefei, China
| | - Xiao-Xu Yang
- Hefei National Research Center for Physical Sciences at the Microscale, CAS Key Laboratory of Brain Function and Disease, Ministry of Education Key Laboratory for Membrane-less Organelles and Cellular Dynamics, Division of Life Sciences and Medicine, University of Science and Technology of China, Hefei, China
- Neurodegenerative Disorder Research Center, Division of Life Sciences and Medicine, University of Science and Technology of China, Hefei, China; Institute on Aging and Brain Disorders, The First Affiliated Hospital of USTC, Division of Life Sciences and Medicine, University of Sciences and Technology of China, Hefei, China
- Anhui Province Key Laboratory of Biomedical Aging Research, University of Science and Technology of China, Hefei, China
| | - Xu-Zhuo Gou
- Hefei National Research Center for Physical Sciences at the Microscale, CAS Key Laboratory of Brain Function and Disease, Ministry of Education Key Laboratory for Membrane-less Organelles and Cellular Dynamics, Division of Life Sciences and Medicine, University of Science and Technology of China, Hefei, China
- Institute of Artificial Intelligence, Hefei Comprehensive National Science Center, Hefei, China
| | - Shu-Mei Fu
- Hefei National Research Center for Physical Sciences at the Microscale, CAS Key Laboratory of Brain Function and Disease, Ministry of Education Key Laboratory for Membrane-less Organelles and Cellular Dynamics, Division of Life Sciences and Medicine, University of Science and Technology of China, Hefei, China
- Neurodegenerative Disorder Research Center, Division of Life Sciences and Medicine, University of Science and Technology of China, Hefei, China; Institute on Aging and Brain Disorders, The First Affiliated Hospital of USTC, Division of Life Sciences and Medicine, University of Sciences and Technology of China, Hefei, China
- Anhui Province Key Laboratory of Biomedical Aging Research, University of Science and Technology of China, Hefei, China
| | - Jia-Hui Chen
- Hefei National Research Center for Physical Sciences at the Microscale, CAS Key Laboratory of Brain Function and Disease, Ministry of Education Key Laboratory for Membrane-less Organelles and Cellular Dynamics, Division of Life Sciences and Medicine, University of Science and Technology of China, Hefei, China
- Institute of Artificial Intelligence, Hefei Comprehensive National Science Center, Hefei, China
- Anhui Province Key Laboratory of Biomedical Aging Research, University of Science and Technology of China, Hefei, China
| | - Feng Gao
- Neurodegenerative Disorder Research Center, Division of Life Sciences and Medicine, University of Science and Technology of China, Hefei, China; Institute on Aging and Brain Disorders, The First Affiliated Hospital of USTC, Division of Life Sciences and Medicine, University of Sciences and Technology of China, Hefei, China
| | - Yong Shen
- Neurodegenerative Disorder Research Center, Division of Life Sciences and Medicine, University of Science and Technology of China, Hefei, China; Institute on Aging and Brain Disorders, The First Affiliated Hospital of USTC, Division of Life Sciences and Medicine, University of Sciences and Technology of China, Hefei, China
- Anhui Province Key Laboratory of Biomedical Aging Research, University of Science and Technology of China, Hefei, China
- Center for Excellence in Brain Science and Intelligence Technology, Chinese Academy of Sciences, China
| | - Dan-Lei Bi
- Institute of Artificial Intelligence, Hefei Comprehensive National Science Center, Hefei, China
- Neurodegenerative Disorder Research Center, Division of Life Sciences and Medicine, University of Science and Technology of China, Hefei, China; Institute on Aging and Brain Disorders, The First Affiliated Hospital of USTC, Division of Life Sciences and Medicine, University of Sciences and Technology of China, Hefei, China
- Anhui Province Key Laboratory of Biomedical Aging Research, University of Science and Technology of China, Hefei, China
- Center for Excellence in Brain Science and Intelligence Technology, Chinese Academy of Sciences, China
| | - Ai-Hui Tang
- Hefei National Research Center for Physical Sciences at the Microscale, CAS Key Laboratory of Brain Function and Disease, Ministry of Education Key Laboratory for Membrane-less Organelles and Cellular Dynamics, Division of Life Sciences and Medicine, University of Science and Technology of China, Hefei, China
- Institute of Artificial Intelligence, Hefei Comprehensive National Science Center, Hefei, China
- Neurodegenerative Disorder Research Center, Division of Life Sciences and Medicine, University of Science and Technology of China, Hefei, China; Institute on Aging and Brain Disorders, The First Affiliated Hospital of USTC, Division of Life Sciences and Medicine, University of Sciences and Technology of China, Hefei, China
- Anhui Province Key Laboratory of Biomedical Aging Research, University of Science and Technology of China, Hefei, China
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5
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Choi SB, Kwon S, Kim JH, Ahn NH, Lee JH, Yang SH. The Molecular Mechanisms of Neuroinflammation in Alzheimer's Disease, the Consequence of Neural Cell Death. Int J Mol Sci 2023; 24:11757. [PMID: 37511515 PMCID: PMC10380735 DOI: 10.3390/ijms241411757] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2023] [Revised: 07/17/2023] [Accepted: 07/20/2023] [Indexed: 07/30/2023] Open
Abstract
Alzheimer's disease (AD) is accompanied by neural cell loss and memory deficit. Neural cell death, occurring via apoptosis and autophagy, is widely observed in the AD brain in addition to neuroinflammation mediated by necroptosis and the NLRP3 inflammasome. Neurotoxicity induced by amyloid-beta (Aβ) and tau aggregates leads to excessive neural cell death and neuroinflammation in the AD brain. During AD progression, uncontrolled neural cell death results in the dysregulation of cellular activity and synaptic function. Apoptosis mediated by pro-apoptotic caspases, autophagy regulated by autophagy-related proteins, and necroptosis controlled by the RIPK/MLKL axis are representative of neural cell death occurred during AD. Necroptosis causes the release of cellular components, contributing to the pro-inflammatory environment in the AD brain. Inordinately high levels of neural cell death and pro-inflammatory events lead to the production of pro-inflammatory cytokines and feed-forward hyper neuroinflammation. Thus, neural cell death and neuroinflammation cause synaptic dysfunction and memory deficits in the AD brain. In this review, we briefly introduce the mechanisms of neural cell death and neuroinflammation observed in the AD brain. Combined with a typical strategy for targeting Aβ and tau, regulation of neural cell death and neuroinflammation may be effective for the amelioration of AD pathologies.
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Affiliation(s)
- Su-Bin Choi
- Department of Biomedical Engineering, College of Life Science and Biotechnology, Dongguk University, Seoul 04620, Republic of Korea
| | - Sehee Kwon
- Department of Biomedical Engineering, College of Life Science and Biotechnology, Dongguk University, Seoul 04620, Republic of Korea
| | - Ji-Hye Kim
- Department of Biomedical Engineering, College of Life Science and Biotechnology, Dongguk University, Seoul 04620, Republic of Korea
| | - Na-Hyun Ahn
- Department of Biomedical Engineering, College of Life Science and Biotechnology, Dongguk University, Seoul 04620, Republic of Korea
| | - Joo-Hee Lee
- Department of Biomedical Engineering, College of Life Science and Biotechnology, Dongguk University, Seoul 04620, Republic of Korea
| | - Seung-Hoon Yang
- Department of Biomedical Engineering, College of Life Science and Biotechnology, Dongguk University, Seoul 04620, Republic of Korea
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6
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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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7
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Mohamed Asik R, Suganthy N, Aarifa MA, Kumar A, Szigeti K, Mathe D, Gulyás B, Archunan G, Padmanabhan P. Alzheimer's Disease: A Molecular View of β-Amyloid Induced Morbific Events. Biomedicines 2021; 9:biomedicines9091126. [PMID: 34572312 PMCID: PMC8468668 DOI: 10.3390/biomedicines9091126] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2021] [Revised: 08/22/2021] [Accepted: 08/27/2021] [Indexed: 12/26/2022] Open
Abstract
Amyloid-β (Aβ) is a dynamic peptide of Alzheimer’s disease (AD) which accelerates the disease progression. At the cell membrane and cell compartments, the amyloid precursor protein (APP) undergoes amyloidogenic cleavage by β- and γ-secretases and engenders the Aβ. In addition, externally produced Aβ gets inside the cells by receptors mediated internalization. An elevated amount of Aβ yields spontaneous aggregation which causes organelles impairment. Aβ stimulates the hyperphosphorylation of tau protein via acceleration by several kinases. Aβ travels to the mitochondria and interacts with its functional complexes, which impairs the mitochondrial function leading to the activation of apoptotic signaling cascade. Aβ disrupts the Ca2+ and protein homeostasis of the endoplasmic reticulum (ER) and Golgi complex (GC) that promotes the organelle stress and inhibits its stress recovery machinery such as unfolded protein response (UPR) and ER-associated degradation (ERAD). At lysosome, Aβ precedes autophagy dysfunction upon interacting with autophagy molecules. Interestingly, Aβ act as a transcription regulator as well as inhibits telomerase activity. Both Aβ and p-tau interaction with neuronal and glial receptors elevate the inflammatory molecules and persuade inflammation. Here, we have expounded the Aβ mediated events in the cells and its cosmopolitan role on neurodegeneration, and the current clinical status of anti-amyloid therapy.
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Affiliation(s)
- Rajmohamed Mohamed Asik
- Lee Kong Chian School of Medicine, Nanyang Technological University, Singapore 636921, Singapore; (R.M.A.); (B.G.)
- Cognitive Neuroimaging Centre, 59 Nanyang Drive, Nanyang Technological University, Singapore 636921, Singapore
- Department of Animal Science, Bharathidasan University, Tiruchirappalli 620024, Tamil Nadu, India;
| | - Natarajan Suganthy
- Department of Nanoscience and Technology, Alagappa University, Karaikudi 630003, Tamil Nadu, India;
| | - Mohamed Asik Aarifa
- Department of Animal Science, Bharathidasan University, Tiruchirappalli 620024, Tamil Nadu, India;
| | - Arvind Kumar
- Centre for Cellular and Molecular Biology, Hyderabad 500007, Telangana, India;
| | - Krisztián Szigeti
- Department of Biophysics and Radiation Biology, Semmelweis University, 1094 Budapest, Hungary; (K.S.); (D.M.)
- CROmed Translational Research Centers, 1094 Budapest, Hungary
| | - Domokos Mathe
- Department of Biophysics and Radiation Biology, Semmelweis University, 1094 Budapest, Hungary; (K.S.); (D.M.)
- CROmed Translational Research Centers, 1094 Budapest, Hungary
- In Vivo Imaging Advanced Core Facility, Hungarian Center of Excellence for Molecular Medicine (HCEMM), 1094 Budapest, Hungary
| | - Balázs Gulyás
- Lee Kong Chian School of Medicine, Nanyang Technological University, Singapore 636921, Singapore; (R.M.A.); (B.G.)
- Cognitive Neuroimaging Centre, 59 Nanyang Drive, Nanyang Technological University, Singapore 636921, Singapore
- Department of Clinical Neuroscience, Karolinska Institute, 17176 Stockholm, Sweden
| | - Govindaraju Archunan
- Department of Animal Science, Bharathidasan University, Tiruchirappalli 620024, Tamil Nadu, India;
- Marudupandiyar College, Thanjavur 613403, Tamil Nadu, India
- Correspondence: (G.A.); (P.P.)
| | - Parasuraman Padmanabhan
- Lee Kong Chian School of Medicine, Nanyang Technological University, Singapore 636921, Singapore; (R.M.A.); (B.G.)
- Cognitive Neuroimaging Centre, 59 Nanyang Drive, Nanyang Technological University, Singapore 636921, Singapore
- Correspondence: (G.A.); (P.P.)
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8
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Schützmann MP, Hasecke F, Bachmann S, Zielinski M, Hänsch S, Schröder GF, Zempel H, Hoyer W. Endo-lysosomal Aβ concentration and pH trigger formation of Aβ oligomers that potently induce Tau missorting. Nat Commun 2021; 12:4634. [PMID: 34330900 PMCID: PMC8324842 DOI: 10.1038/s41467-021-24900-4] [Citation(s) in RCA: 52] [Impact Index Per Article: 17.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2020] [Accepted: 07/14/2021] [Indexed: 02/08/2023] Open
Abstract
Amyloid-β peptide (Aβ) forms metastable oligomers >50 kDa, termed AβOs, that are more effective than Aβ amyloid fibrils at triggering Alzheimer’s disease-related processes such as synaptic dysfunction and Tau pathology, including Tau mislocalization. In neurons, Aβ accumulates in endo-lysosomal vesicles at low pH. Here, we show that the rate of AβO assembly is accelerated 8,000-fold upon pH reduction from extracellular to endo-lysosomal pH, at the expense of amyloid fibril formation. The pH-induced promotion of AβO formation and the high endo-lysosomal Aβ concentration together enable extensive AβO formation of Aβ42 under physiological conditions. Exploiting the enhanced AβO formation of the dimeric Aβ variant dimAβ we furthermore demonstrate targeting of AβOs to dendritic spines, potent induction of Tau missorting, a key factor in tauopathies, and impaired neuronal activity. The results suggest that the endosomal/lysosomal system is a major site for the assembly of pathomechanistically relevant AβOs. Aβ oligomers (AβO) are thought to represent the main toxic species in Alzheimer’s disease but very high Aβ concentrations are required to study them in vitro and it remains unknown what role these off-pathway oligomers play in vivo. Here, the authors use a dimeric variant of Aβ termed dimAβ, where two Aβ40 units are linked, which facilitates to study AβO formation kinetics and they observe that Aβ off-pathway oligomer formation is strongly accelerated at endo-lysosomal pH, while amyloid fibril formation is delayed. Furthermore, the authors demonstrate that dimAβ is a disease-relevant model construct for pathogenic AβO formation by showing that dimAβ AβOs target dendritic spines and induce AD-like somatodendritic Tau missorting.
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Affiliation(s)
- Marie P Schützmann
- Institut für Physikalische Biologie, Heinrich-Heine-Universität Düsseldorf, Düsseldorf, Germany
| | - Filip Hasecke
- Institut für Physikalische Biologie, Heinrich-Heine-Universität Düsseldorf, Düsseldorf, Germany
| | - Sarah Bachmann
- Institute of Human Genetics and Center for Molecular Medicine Cologne (CMMC), University of Cologne, Faculty of Medicine and University Hospital Cologne, Cologne, Germany
| | - Mara Zielinski
- Institute of Biological Information Processing (IBI-7) and JuStruct: Jülich Center for Structural Biology, Forschungszentrum Jülich, Jülich, Germany
| | - Sebastian Hänsch
- Department of Biology, Center for Advanced Imaging (CAi), Heinrich-Heine-Universität Düsseldorf, Düsseldorf, Germany
| | - Gunnar F Schröder
- Institute of Biological Information Processing (IBI-7) and JuStruct: Jülich Center for Structural Biology, Forschungszentrum Jülich, Jülich, Germany.,Physics Department, Heinrich-Heine-Universität Düsseldorf, Düsseldorf, Germany
| | - Hans Zempel
- Institute of Human Genetics and Center for Molecular Medicine Cologne (CMMC), University of Cologne, Faculty of Medicine and University Hospital Cologne, Cologne, Germany.
| | - Wolfgang Hoyer
- Institut für Physikalische Biologie, Heinrich-Heine-Universität Düsseldorf, Düsseldorf, Germany. .,Institute of Biological Information Processing (IBI-7) and JuStruct: Jülich Center for Structural Biology, Forschungszentrum Jülich, Jülich, Germany.
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9
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Lynn SA, Johnston DA, Scott JA, Munday R, Desai RS, Keeling E, Weaterton R, Simpson A, Davis D, Freeman T, Chatelet DS, Page A, Cree AJ, Lee H, Newman TA, Lotery AJ, Ratnayaka JA. Oligomeric Aβ 1-42 Induces an AMD-Like Phenotype and Accumulates in Lysosomes to Impair RPE Function. Cells 2021; 10:413. [PMID: 33671133 PMCID: PMC7922851 DOI: 10.3390/cells10020413] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2021] [Revised: 02/04/2021] [Accepted: 02/11/2021] [Indexed: 12/12/2022] Open
Abstract
Alzheimer's disease-associated amyloid beta (Aβ) proteins accumulate in the outer retina with increasing age and in eyes of age-related macular degeneration (AMD) patients. To study Aβ-induced retinopathy, wild-type mice were injected with nanomolar human oligomeric Aβ1-42, which recapitulate the Aβ burden reported in human donor eyes. In vitro studies investigated the cellular effects of Aβ in endothelial and retinal pigment epithelial (RPE) cells. Results show subretinal Aβ-induced focal AMD-like pathology within 2 weeks. Aβ exposure caused endothelial cell migration, and morphological and barrier alterations to the RPE. Aβ co-localized to late-endocytic compartments of RPE cells, which persisted despite attempts to clear it through upregulation of lysosomal cathepsin B, revealing a novel mechanism of lysosomal impairment in retinal degeneration. The rapid upregulation of cathepsin B was out of step with the prolonged accumulation of Aβ within lysosomes, and contrasted with enzymatic responses to internalized photoreceptor outer segments (POS). Furthermore, RPE cells exposed to Aβ were identified as deficient in cargo-carrying lysosomes at time points that are critical to POS degradation. These findings imply that Aβ accumulation within late-endocytic compartments, as well as lysosomal deficiency, impairs RPE function over time, contributing to visual defects seen in aging and AMD eyes.
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Affiliation(s)
- Savannah A. Lynn
- Clinical and Experimental Sciences, Faculty of Medicine, University of Southampton, MP 806, Tremona Road, Southampton SO16 6YD, UK; (S.A.L.); (J.A.S.); (R.M.); (R.S.D.); (E.K.); (R.W.); (A.S.); (D.D.); (T.F.); (A.J.C.); (H.L.); (T.A.N.); (A.J.L.)
| | - David A. Johnston
- Biomedical Imaging Unit, University of Southampton, MP12, Tremona Road, Southampton SO16 6YD, UK; (D.A.J.); (D.S.C.); (A.P.)
| | - Jenny A. Scott
- Clinical and Experimental Sciences, Faculty of Medicine, University of Southampton, MP 806, Tremona Road, Southampton SO16 6YD, UK; (S.A.L.); (J.A.S.); (R.M.); (R.S.D.); (E.K.); (R.W.); (A.S.); (D.D.); (T.F.); (A.J.C.); (H.L.); (T.A.N.); (A.J.L.)
| | - Rosie Munday
- Clinical and Experimental Sciences, Faculty of Medicine, University of Southampton, MP 806, Tremona Road, Southampton SO16 6YD, UK; (S.A.L.); (J.A.S.); (R.M.); (R.S.D.); (E.K.); (R.W.); (A.S.); (D.D.); (T.F.); (A.J.C.); (H.L.); (T.A.N.); (A.J.L.)
| | - Roshni S. Desai
- Clinical and Experimental Sciences, Faculty of Medicine, University of Southampton, MP 806, Tremona Road, Southampton SO16 6YD, UK; (S.A.L.); (J.A.S.); (R.M.); (R.S.D.); (E.K.); (R.W.); (A.S.); (D.D.); (T.F.); (A.J.C.); (H.L.); (T.A.N.); (A.J.L.)
| | - Eloise Keeling
- Clinical and Experimental Sciences, Faculty of Medicine, University of Southampton, MP 806, Tremona Road, Southampton SO16 6YD, UK; (S.A.L.); (J.A.S.); (R.M.); (R.S.D.); (E.K.); (R.W.); (A.S.); (D.D.); (T.F.); (A.J.C.); (H.L.); (T.A.N.); (A.J.L.)
| | - Ruaridh Weaterton
- Clinical and Experimental Sciences, Faculty of Medicine, University of Southampton, MP 806, Tremona Road, Southampton SO16 6YD, UK; (S.A.L.); (J.A.S.); (R.M.); (R.S.D.); (E.K.); (R.W.); (A.S.); (D.D.); (T.F.); (A.J.C.); (H.L.); (T.A.N.); (A.J.L.)
| | - Alexander Simpson
- Clinical and Experimental Sciences, Faculty of Medicine, University of Southampton, MP 806, Tremona Road, Southampton SO16 6YD, UK; (S.A.L.); (J.A.S.); (R.M.); (R.S.D.); (E.K.); (R.W.); (A.S.); (D.D.); (T.F.); (A.J.C.); (H.L.); (T.A.N.); (A.J.L.)
| | - Dillon Davis
- Clinical and Experimental Sciences, Faculty of Medicine, University of Southampton, MP 806, Tremona Road, Southampton SO16 6YD, UK; (S.A.L.); (J.A.S.); (R.M.); (R.S.D.); (E.K.); (R.W.); (A.S.); (D.D.); (T.F.); (A.J.C.); (H.L.); (T.A.N.); (A.J.L.)
| | - Thomas Freeman
- Clinical and Experimental Sciences, Faculty of Medicine, University of Southampton, MP 806, Tremona Road, Southampton SO16 6YD, UK; (S.A.L.); (J.A.S.); (R.M.); (R.S.D.); (E.K.); (R.W.); (A.S.); (D.D.); (T.F.); (A.J.C.); (H.L.); (T.A.N.); (A.J.L.)
| | - David S. Chatelet
- Biomedical Imaging Unit, University of Southampton, MP12, Tremona Road, Southampton SO16 6YD, UK; (D.A.J.); (D.S.C.); (A.P.)
| | - Anton Page
- Biomedical Imaging Unit, University of Southampton, MP12, Tremona Road, Southampton SO16 6YD, UK; (D.A.J.); (D.S.C.); (A.P.)
| | - Angela J. Cree
- Clinical and Experimental Sciences, Faculty of Medicine, University of Southampton, MP 806, Tremona Road, Southampton SO16 6YD, UK; (S.A.L.); (J.A.S.); (R.M.); (R.S.D.); (E.K.); (R.W.); (A.S.); (D.D.); (T.F.); (A.J.C.); (H.L.); (T.A.N.); (A.J.L.)
| | - Helena Lee
- Clinical and Experimental Sciences, Faculty of Medicine, University of Southampton, MP 806, Tremona Road, Southampton SO16 6YD, UK; (S.A.L.); (J.A.S.); (R.M.); (R.S.D.); (E.K.); (R.W.); (A.S.); (D.D.); (T.F.); (A.J.C.); (H.L.); (T.A.N.); (A.J.L.)
- Eye Unit, University Hospital Southampton NHS Foundation Trust, Southampton SO16 6YD, UK
| | - Tracey A. Newman
- Clinical and Experimental Sciences, Faculty of Medicine, University of Southampton, MP 806, Tremona Road, Southampton SO16 6YD, UK; (S.A.L.); (J.A.S.); (R.M.); (R.S.D.); (E.K.); (R.W.); (A.S.); (D.D.); (T.F.); (A.J.C.); (H.L.); (T.A.N.); (A.J.L.)
| | - Andrew J. Lotery
- Clinical and Experimental Sciences, Faculty of Medicine, University of Southampton, MP 806, Tremona Road, Southampton SO16 6YD, UK; (S.A.L.); (J.A.S.); (R.M.); (R.S.D.); (E.K.); (R.W.); (A.S.); (D.D.); (T.F.); (A.J.C.); (H.L.); (T.A.N.); (A.J.L.)
- Eye Unit, University Hospital Southampton NHS Foundation Trust, Southampton SO16 6YD, UK
| | - J. Arjuna Ratnayaka
- Clinical and Experimental Sciences, Faculty of Medicine, University of Southampton, MP 806, Tremona Road, Southampton SO16 6YD, UK; (S.A.L.); (J.A.S.); (R.M.); (R.S.D.); (E.K.); (R.W.); (A.S.); (D.D.); (T.F.); (A.J.C.); (H.L.); (T.A.N.); (A.J.L.)
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10
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Marshall KE, Vadukul DM, Staras K, Serpell LC. Misfolded amyloid-β-42 impairs the endosomal-lysosomal pathway. Cell Mol Life Sci 2020; 77:5031-5043. [PMID: 32025743 PMCID: PMC7658065 DOI: 10.1007/s00018-020-03464-4] [Citation(s) in RCA: 24] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2019] [Revised: 01/13/2020] [Accepted: 01/14/2020] [Indexed: 12/29/2022]
Abstract
Misfolding and aggregation of proteins is strongly linked to several neurodegenerative diseases, but how such species bring about their cytotoxic actions remains poorly understood. Here we used specifically-designed optical reporter probes and live fluorescence imaging in primary hippocampal neurons to characterise the mechanism by which prefibrillar, oligomeric forms of the Alzheimer's-associated peptide, Aβ42, exert their detrimental effects. We used a pH-sensitive reporter, Aβ42-CypHer, to track Aβ internalisation in real-time, demonstrating that oligomers are rapidly taken up into cells in a dynamin-dependent manner, and trafficked via the endo-lysosomal pathway resulting in accumulation in lysosomes. In contrast, a non-assembling variant of Aβ42 (vAβ42) assayed in the same way is not internalised. Tracking ovalbumin uptake into cells using CypHer or Alexa Fluor tags shows that preincubation with Aβ42 disrupts protein uptake. Our results identify a potential mechanism by which amyloidogenic aggregates impair cellular function through disruption of the endosomal-lysosomal pathway.
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Affiliation(s)
- Karen E Marshall
- Sussex Neuroscience, School of Life Sciences, University of Sussex, Falmer, BN1 9QG, UK
| | - Devkee M Vadukul
- Sussex Neuroscience, School of Life Sciences, University of Sussex, Falmer, BN1 9QG, UK
| | - Kevin Staras
- Sussex Neuroscience, School of Life Sciences, University of Sussex, Falmer, BN1 9QG, UK.
| | - Louise C Serpell
- Sussex Neuroscience, School of Life Sciences, University of Sussex, Falmer, BN1 9QG, UK.
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11
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Vadukul DM, Maina M, Franklin H, Nardecchia A, Serpell LC, Marshall KE. Internalisation and toxicity of amyloid-β 1-42 are influenced by its conformation and assembly state rather than size. FEBS Lett 2020; 594:3490-3503. [PMID: 32871611 DOI: 10.1002/1873-3468.13919] [Citation(s) in RCA: 23] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2020] [Revised: 07/30/2020] [Accepted: 08/19/2020] [Indexed: 01/18/2023]
Abstract
Amyloid fibrils found in plaques in Alzheimer's disease (AD) brains are composed of amyloid-β peptides. Oligomeric amyloid-β 1-42 (Aβ42) is thought to play a critical role in neurodegeneration in AD. Here, we determine how size and conformation affect neurotoxicity and internalisation of Aβ42 assemblies using biophysical methods, immunoblotting, toxicity assays and live-cell imaging. We report significant cytotoxicity of Aβ42 oligomers and their internalisation into neurons. In contrast, Aβ42 fibrils show reduced internalisation and no toxicity. Sonicating Aβ42 fibrils generates species similar in size to oligomers but remains nontoxic. The results suggest that Aβ42 oligomers have unique properties that underlie their neurotoxic potential. Furthermore, we show that incubating cells with Aβ42 oligomers for 24 h is sufficient to trigger irreversible neurotoxicity.
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Affiliation(s)
- Devkee M Vadukul
- Dementia Research group, Sussex Neuroscience, School of Life Sciences, University of Sussex, Falmer, E Sussex, UK.,CEMO-Alzheimer Dementia group, Institute of Neuroscience, Université catholique de Louvain, Brussels, Belgium
| | - Mahmoud Maina
- Dementia Research group, Sussex Neuroscience, School of Life Sciences, University of Sussex, Falmer, E Sussex, UK.,College of Medical Sciences, Yobe State University, Nigeria
| | - Hannah Franklin
- Dementia Research group, Sussex Neuroscience, School of Life Sciences, University of Sussex, Falmer, E Sussex, UK
| | - Astrid Nardecchia
- Dementia Research group, Sussex Neuroscience, School of Life Sciences, University of Sussex, Falmer, E Sussex, UK
| | - Louise C Serpell
- Dementia Research group, Sussex Neuroscience, School of Life Sciences, University of Sussex, Falmer, E Sussex, UK
| | - Karen E Marshall
- Dementia Research group, Sussex Neuroscience, School of Life Sciences, University of Sussex, Falmer, E Sussex, UK
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12
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Metal- and UV- Catalyzed Oxidation Results in Trapped Amyloid-β Intermediates Revealing that Self-Assembly Is Required for Aβ-Induced Cytotoxicity. iScience 2020; 23:101537. [PMID: 33083713 PMCID: PMC7516296 DOI: 10.1016/j.isci.2020.101537] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2020] [Revised: 06/05/2020] [Accepted: 09/03/2020] [Indexed: 02/08/2023] Open
Abstract
Dityrosine (DiY), via the cross-linking of tyrosine residues, is a marker of protein oxidation, which increases with aging. Amyloid-β (Aβ) forms DiY in vitro and DiY-cross-linked Aβ is found in the brains of patients with Alzheimer disease. Metal- or UV- catalyzed oxidation of Aβ42 results in an increase in DiY cross-links. Using DiY as a marker of oxidation, we compare the self-assembly propensity and DiY cross-link formation for a non-assembly competent variant of Aβ42 (vAβ) with wild-type Aβ42. Oxidation results in the formation of trapped wild-type Aβ assemblies with increased DiY cross-links that are unable to elongate further. Assembly-incompetent vAβ and trapped Aβ assemblies are non-toxic to neuroblastoma cells at all stages of self-assembly, in contrast to oligomeric, non-cross-linked Aβ. These findings point to a mechanism of toxicity that necessitates dynamic self-assembly whereby trapped Aβ assemblies and assembly-incompetent variant Aβ are unable to result in cell death. Metal- (Cu2+ H202) or UV- catalyzedoxidation results in dityrosine (DiY) formation Oxidation results in DiY cross-link formation in Aβ and halts further assembly Non-assembling Aβ (trapped Aβ or variant Αβ monomer) is not cytotoxic
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13
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Wang Y, Wu Q, Anand BG, Karthivashan G, Phukan G, Yang J, Thinakaran G, Westaway D, Kar S. Significance of cytosolic cathepsin D in Alzheimer's disease pathology: Protective cellular effects of PLGA nanoparticles against β-amyloid-toxicity. Neuropathol Appl Neurobiol 2020; 46:686-706. [PMID: 32716575 DOI: 10.1111/nan.12647] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2020] [Revised: 06/25/2020] [Accepted: 07/12/2020] [Indexed: 12/16/2022]
Abstract
BACKGROUND Evidence suggests that amyloid β (Aβ) peptides play an important role in the degeneration of neurons during the development of Alzheimer's disease (AD), the prevalent cause of dementia affecting the elderly. The endosomal-lysosomal system, which acts as a major site for Aβ metabolism, has been shown to exhibit abnormalities in vulnerable neurons of the AD brain, reflected by enhanced levels/expression of lysosomal enzymes including cathepsin D (CatD). At present, the implication of CatD in selective neuronal vulnerability in AD pathology remains unclear. METHODS We evaluated the role of CatD in the degeneration of neurons in Aβ-treated cultures, transgenic AD mouse model (that is 5xFAD) and post mortem AD brain samples. RESULTS Our results showed that Aβ1-42 -induced toxicity in cortical cultured neurons is associated with impaired lysosomal integrity, enhanced levels of carbonylated proteins and tau phosphorylation. The cellular and cytosolic levels/activity of CatD are also elevated in cultured neurons following exposure to Aβ peptide. Additionally, we observed that CatD cellular and subcellular levels/activity are increased in the affected cortex, but not in the unaffected cerebellum, of 5xFAD mice and post mortem AD brains. Interestingly, treatment of cultured neurons with nanoparticles PLGA, which targets lysosomal system, attenuated Aβ toxicity by reducing the levels of carbonylated proteins, tau phosphorylation and the level/distribution/activity of CatD. CONCLUSION Our study reveals that increased cytosolic level/activity of CatD play an important role in determining neuronal vulnerability in AD. Additionally, native PLGA can protect neurons against Aβ toxicity by restoring lysosomal membrane integrity, thus signifying its implication in attenuating AD.
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Affiliation(s)
- Y Wang
- Department of Psychiatry, University of Alberta, Edmonton, Alberta, Canada.,Department of Medicine, University of Alberta, Edmonton, Alberta, Canada.,Centre for Prions and Protein Folding Diseases, University of Alberta, Edmonton, Alberta, Canada
| | - Q Wu
- Department of Medicine, University of Alberta, Edmonton, Alberta, Canada.,Centre for Prions and Protein Folding Diseases, University of Alberta, Edmonton, Alberta, Canada
| | - B G Anand
- Department of Medicine, University of Alberta, Edmonton, Alberta, Canada.,Centre for Prions and Protein Folding Diseases, University of Alberta, Edmonton, Alberta, Canada
| | - G Karthivashan
- Department of Medicine, University of Alberta, Edmonton, Alberta, Canada.,Centre for Prions and Protein Folding Diseases, University of Alberta, Edmonton, Alberta, Canada
| | - G Phukan
- Department of Medicine, University of Alberta, Edmonton, Alberta, Canada.,Centre for Prions and Protein Folding Diseases, University of Alberta, Edmonton, Alberta, Canada
| | - J Yang
- Centre for Prions and Protein Folding Diseases, University of Alberta, Edmonton, Alberta, Canada
| | - G Thinakaran
- Department of Molecular Medicine, and Byrd Alzheimer's Institute, University of South Florida, Tampa, FL, 33613, USA
| | - D Westaway
- Department of Medicine, University of Alberta, Edmonton, Alberta, Canada.,Centre for Prions and Protein Folding Diseases, University of Alberta, Edmonton, Alberta, Canada.,Department of Biochemistry, University of Alberta, Edmonton, Alberta, Canada
| | - S Kar
- Department of Psychiatry, University of Alberta, Edmonton, Alberta, Canada.,Department of Medicine, University of Alberta, Edmonton, Alberta, Canada.,Centre for Prions and Protein Folding Diseases, University of Alberta, Edmonton, Alberta, Canada
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14
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Icariin Ameliorates Amyloid Pathologies by Maintaining Homeostasis of Autophagic Systems in Aβ1–42-Injected Rats. Neurochem Res 2019; 44:2708-2722. [DOI: 10.1007/s11064-019-02889-z] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2019] [Revised: 09/26/2019] [Accepted: 10/03/2019] [Indexed: 12/22/2022]
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15
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Keeling E, Chatelet DS, Johnston DA, Page A, Tumbarello DA, Lotery AJ, Ratnayaka JA. Oxidative Stress and Dysfunctional Intracellular Traffic Linked to an Unhealthy Diet Results in Impaired Cargo Transport in the Retinal Pigment Epithelium (RPE). Mol Nutr Food Res 2019; 63:e1800951. [PMID: 30835933 DOI: 10.1002/mnfr.201800951] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2018] [Revised: 01/18/2019] [Indexed: 12/19/2022]
Abstract
SCOPE Oxidative stress and dysregulated intracellular trafficking are associated with an unhealthy diet which underlies pathology. Here, these effects on photoreceptor outer segment (POS) trafficking in the retinal pigment epithelium (RPE), a major pathway of disease underlying irreversible sight-loss, are studied. METHODS AND RESULTS POS trafficking is studied in ARPE-19 cells using an algorithm-based quantification of confocal-immunofluorescence data supported by ultrastructural studies. It is shown that although POS are tightly regulated and trafficked via Rab5, Rab7 vesicles, LAMP1/2 lysosomes and LC3b-autophagosomes, there is also a considerable degree of variation and flexibility in this process. Treatment with H2 O2 and bafilomycin A1 reveals that oxidative stress and dysregulated autophagy target intracellular compartments and trafficking in strikingly different ways. These effects appear limited to POS-containing vesicles, suggesting a cargo-specific effect. CONCLUSION The findings offer insights into how RPE cells cope with stress, and how mechanisms influencing POS transport/degradation can have different outcomes in the senescent retina. These shed new light on cellular processes underlying retinopathies such as age-related macular degeneration. The discoveries reveal how diet and nutrition can cause fundamental alterations at a cellular level, thus contributing to a better understanding of the diet-disease axis.
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Affiliation(s)
- Eloise Keeling
- Clinical and Experimental Sciences, Faculty of Medicine, University of Southampton, MP806, Tremona Road, SO16 6YD, UK
| | - David S Chatelet
- Biomedical Imaging Unit, University of Southampton, MP12, Tremona Road, SO16 6YD, UK
| | - David A Johnston
- Biomedical Imaging Unit, University of Southampton, MP12, Tremona Road, SO16 6YD, UK
| | - Anton Page
- Biomedical Imaging Unit, University of Southampton, MP12, Tremona Road, SO16 6YD, UK
| | - David A Tumbarello
- Biological Sciences, Faculty of Natural & Environmental Sciences, University of Southampton, Life Sciences Building 85, SO17 1BJ, UK
| | - Andrew J Lotery
- Clinical and Experimental Sciences, Faculty of Medicine, University of Southampton, MP806, Tremona Road, SO16 6YD, UK
- Eye Unit, University Hospital Southampton NHS Foundation Trust, Southampton, SO16 6YD, UK
| | - J Arjuna Ratnayaka
- Clinical and Experimental Sciences, Faculty of Medicine, University of Southampton, MP806, Tremona Road, SO16 6YD, UK
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16
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Amyloid Peptide β1-42 Induces Integrin αIIb β3 Activation, Platelet Adhesion, and Thrombus Formation in a NADPH Oxidase-Dependent Manner. OXIDATIVE MEDICINE AND CELLULAR LONGEVITY 2019; 2019:1050476. [PMID: 31007831 PMCID: PMC6441506 DOI: 10.1155/2019/1050476] [Citation(s) in RCA: 28] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/23/2018] [Revised: 11/05/2018] [Accepted: 12/13/2018] [Indexed: 01/02/2023]
Abstract
The progression of Alzheimer's dementia is associated with neurovasculature impairment, which includes inflammation, microthromboses, and reduced cerebral blood flow. Here, we investigate the effects of β amyloid peptides on the function of platelets, the cells driving haemostasis. Amyloid peptide β1-42 (Aβ1-42), Aβ1-40, and Aβ25-35 were tested in static adhesion experiments, and it was found that platelets preferentially adhere to Aβ1-42 compared to other Aβ peptides. In addition, significant platelet spreading was observed over Aβ1-42, while Aβ1-40, Aβ25-35, and the scAβ1-42 control did not seem to induce any platelet spreading, which suggested that only Aβ1-42 activates platelet signalling in our experimental conditions. Aβ1-42 also induced significant platelet adhesion and thrombus formation in whole blood under venous flow condition, while other Aβ peptides did not. The molecular mechanism of Aβ1-42 was investigated by flow cytometry, which revealed that this peptide induces a significant activation of integrin αIIbβ3, but does not induce platelet degranulation (as measured by P-selectin membrane translocation). Finally, Aβ1-42 treatment of human platelets led to detectable levels of protein kinase C (PKC) activation and tyrosine phosphorylation, which are hallmarks of platelet signalling. Interestingly, the NADPH oxidase (NOX) inhibitor VAS2870 completely abolished Aβ1-42-dependent platelet adhesion in static conditions, thrombus formation in physiological flow conditions, integrin αIIbβ3 activation, and tyrosine- and PKC-dependent platelet signalling. In summary, this study highlights the importance of NOXs in the activation of platelets in response to amyloid peptide β1-42. The molecular mechanisms described in this manuscript may play an important role in the neurovascular impairment observed in Alzheimer's patients.
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17
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Anti-neuroinflammatory effects of SLOH in Aβ-induced BV-2 microglial cells and 3xTg-AD mice involve the inhibition of GSK-3β. Neurosci Lett 2018; 687:207-215. [PMID: 30278248 DOI: 10.1016/j.neulet.2018.09.056] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2018] [Revised: 09/06/2018] [Accepted: 09/27/2018] [Indexed: 01/14/2023]
Abstract
Neuroinflammation has been observed in post-mortem Alzheimer's disease (AD) brains which could be due to Aβ interacting with microglia and astrocytes. SLOH, a carbazole-based fluorophore, was shown to bind to Aβ peptides. Herein, we investigated the anti-neuroinflammatory effects of SLOH using a BV-2 microglial cell model and a triple transgenic AD (3xTg-AD) mouse model. BV-2 cells were incubated with Aβ in the presence of SLOH for 24 h. The levels of pro-inflammatory and anti-inflammatory cytokines were determined. Moreover, 3xTg-AD mice were administrated with SLOH (2 mg kg-1) for one month. The mice were then sacrificed and the brains were used to assess the levels of pro-inflammatory, anti-inflammatory cytokines and the activation of ionized calcium-binding adapter molecule 1 (Iba1). BV-2 cell studies suggested that SLOH reduced the production and mRNA levels of pro-inflammatory cytokines TNF-α, IL-1β, COX-2, iNOS, and increased IL-10. Animal study confirmed that SLOH reduced the production of pro-inflammatory cytokines and increased the level of anti-inflammatory cytokine. Moreover, SLOH inhibited the activity of GSK-3β. In 3xTg-AD mouse model, SLOH treatment significantly decreased the number of Iba1-positive cells in mouse brains. Our results demonstrated that SLOH significantly attenuated the neuroinflammation through down-regulating the activity of GSK-3β.
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18
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Maina MB, Bailey LJ, Doherty AJ, Serpell LC. The Involvement of Aβ42 and Tau in Nucleolar and Protein Synthesis Machinery Dysfunction. Front Cell Neurosci 2018; 12:220. [PMID: 30123109 PMCID: PMC6086011 DOI: 10.3389/fncel.2018.00220] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2018] [Accepted: 07/09/2018] [Indexed: 01/29/2023] Open
Abstract
Alzheimer’s disease (AD) is the most common form of dementia and is distinguished from other dementias by observation of extracellular Amyloid-β (Aβ) plaques and intracellular neurofibrillary tangles, comprised of fibrils of Aβ and tau protein, respectively. At early stages, AD is characterized by minimal neurodegeneration, oxidative stress, nucleolar stress, and altered protein synthesis machinery. It is generally believed that Aβ oligomers are the neurotoxic species and their levels in the AD brain correlate with the severity of dementia suggesting that they play a critical role in the pathogenesis of the disease. Here, we show that the incubation of differentiated human neuroblastoma cells (SHSY5Y) with freshly prepared Aβ42 oligomers initially resulted in oxidative stress and subtle nucleolar stress in the absence of DNA damage or cell death. The presence of exogenous Aβ oligomers resulted in altered nuclear tau levels as well as phosphorylation state, leading to altered distribution of nucleolar tau associated with nucleolar stress. These markers of cellular dysfunction worsen over time alongside a reduction in ribosomal RNA synthesis and processing, a decrease in global level of newly synthesized RNA and reduced protein synthesis. The interplay between Aβ and tau in AD remains intriguing and Aβ toxicity has been linked to tau phosphorylation and changes in localization. These findings provide evidence for the involvement of Aβ42 effects on nucleolar tau and protein synthesis machinery dysfunction in cultured cells. Protein synthesis dysfunction is observed in mild cognitive impairment and early AD in the absence of significant neuronal death.
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Affiliation(s)
- Mahmoud B Maina
- School of Life Sciences, University of Sussex, Brighton, United Kingdom.,Department of Human Anatomy, College of Medical Sciences, Gombe State University, Gombe, Nigeria
| | - Laura J Bailey
- Genome Damage and Stability Centre, School of Life Sciences, University of Sussex, Brighton, United Kingdom
| | - Aidan J Doherty
- Genome Damage and Stability Centre, School of Life Sciences, University of Sussex, Brighton, United Kingdom
| | - Louise C Serpell
- School of Life Sciences, University of Sussex, Brighton, United Kingdom
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19
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Maina MB, Bailey LJ, Wagih S, Biasetti L, Pollack SJ, Quinn JP, Thorpe JR, Doherty AJ, Serpell LC. The involvement of tau in nucleolar transcription and the stress response. Acta Neuropathol Commun 2018; 6:70. [PMID: 30064522 PMCID: PMC6066928 DOI: 10.1186/s40478-018-0565-6] [Citation(s) in RCA: 59] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2018] [Accepted: 06/30/2018] [Indexed: 12/16/2022] Open
Abstract
Tau is known for its pathological role in neurodegenerative diseases, including Alzheimer's disease (AD) and other tauopathies. Tau is found in many subcellular compartments such as the cytosol and the nucleus. Although its normal role in microtubule binding is well established, its nuclear role is still unclear. Here, we reveal that tau localises to the nucleolus in undifferentiated and differentiated neuroblastoma cells (SHSY5Y), where it associates with TIP5, a key player in heterochromatin stability and ribosomal DNA (rDNA) transcriptional repression. Immunogold labelling on human brain sample confirms the physiological relevance of this finding by showing tau within the nucleolus colocalises with TIP5. Depletion of tau results in an increase in rDNA transcription with an associated decrease in heterochromatin and DNA methylation, suggesting that under normal conditions tau is involved in silencing of the rDNA. Cellular stress induced by glutamate causes nucleolar stress associated with the redistribution of nucleolar non-phosphorylated tau, in a similar manner to fibrillarin, and nuclear upsurge of phosphorylated tau (Thr231) which doesn't colocalise with fibrillarin or nucleolar tau. This suggests that stress may impact on different nuclear tau species. In addition to involvement in rDNA transcription, nucleolar non-phosphorylated tau also undergoes stress-induced redistribution similar to many nucleolar proteins.
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MESH Headings
- Brain/metabolism
- Brain/ultrastructure
- Cell Differentiation/physiology
- Cell Line, Tumor
- Cell Nucleolus/drug effects
- Cell Nucleolus/metabolism
- Cell Nucleolus/ultrastructure
- Chromosomal Proteins, Non-Histone/metabolism
- Chromosomal Proteins, Non-Histone/ultrastructure
- DNA, Ribosomal/genetics
- DNA, Ribosomal/metabolism
- Excitatory Amino Acid Agonists/pharmacology
- Gene Expression Regulation, Neoplastic/drug effects
- Gene Expression Regulation, Neoplastic/genetics
- Glutamic Acid/pharmacology
- Heterochromatin/physiology
- Histones/metabolism
- Humans
- Immunoprecipitation
- Microscopy, Confocal
- Microscopy, Electron
- Neuroblastoma/pathology
- Neuroblastoma/ultrastructure
- Nuclear Proteins/genetics
- Nuclear Proteins/metabolism
- Protein Transport/drug effects
- RNA, Messenger
- RNA, Small Interfering/genetics
- RNA, Small Interfering/metabolism
- Transcription, Genetic/drug effects
- Transfection
- tau Proteins/genetics
- tau Proteins/metabolism
- tau Proteins/ultrastructure
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Affiliation(s)
- Mahmoud B Maina
- School of Life Sciences, University of Sussex, Falmer, Brighton, East Sussex, BN1 9QG, UK
- Department of Human Anatomy, College of Medical Science, Gombe State University, Gombe, Nigeria
| | - Laura J Bailey
- Genome Damage and Stability Centre, School of Life Sciences, University of Sussex, Brighton, BN1 9RQ, UK
| | - Sherin Wagih
- School of Life Sciences, University of Sussex, Falmer, Brighton, East Sussex, BN1 9QG, UK
| | - Luca Biasetti
- School of Life Sciences, University of Sussex, Falmer, Brighton, East Sussex, BN1 9QG, UK
| | - Saskia J Pollack
- School of Life Sciences, University of Sussex, Falmer, Brighton, East Sussex, BN1 9QG, UK
| | - James P Quinn
- School of Life Sciences, University of Sussex, Falmer, Brighton, East Sussex, BN1 9QG, UK
| | - Julian R Thorpe
- School of Life Sciences, University of Sussex, Falmer, Brighton, East Sussex, BN1 9QG, UK
| | - Aidan J Doherty
- Genome Damage and Stability Centre, School of Life Sciences, University of Sussex, Brighton, BN1 9RQ, UK
| | - Louise C Serpell
- School of Life Sciences, University of Sussex, Falmer, Brighton, East Sussex, BN1 9QG, UK.
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20
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Keeling E, Lotery AJ, Tumbarello DA, Ratnayaka JA. Impaired Cargo Clearance in the Retinal Pigment Epithelium (RPE) Underlies Irreversible Blinding Diseases. Cells 2018; 7:E16. [PMID: 29473871 PMCID: PMC5850104 DOI: 10.3390/cells7020016] [Citation(s) in RCA: 39] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2018] [Revised: 02/20/2018] [Accepted: 02/22/2018] [Indexed: 01/09/2023] Open
Abstract
Chronic degeneration of the Retinal Pigment Epithelium (RPE) is a precursor to pathological changes in the outer retina. The RPE monolayer, which lies beneath the neuroretina, daily internalises and digests large volumes of spent photoreceptor outer segments. Impaired cargo handling and processing in the endocytic/phagosome and autophagy pathways lead to the accumulation of lipofuscin and pyridinium bis-retinoid A2E aggregates and chemically modified compounds such as malondialdehyde and 4-hydroxynonenal within RPE. These contribute to increased proteolytic and oxidative stress, resulting in irreversible damage to post-mitotic RPE cells and development of blinding conditions such as age-related macular degeneration, Stargardt disease and choroideremia. Here, we review how impaired cargo handling in the RPE results in their dysfunction, discuss new findings from our laboratory and consider how newly discovered roles for lysosomes and the autophagy pathway could provide insights into retinopathies. Studies of these dynamic, molecular events have also been spurred on by recent advances in optics and imaging technology. Mechanisms underpinning lysosomal impairment in other degenerative conditions including storage disorders, α-synuclein pathologies and Alzheimer's disease are also discussed. Collectively, these findings help transcend conventional understanding of these intracellular compartments as simple waste disposal bags to bring about a paradigm shift in the way lysosomes are perceived.
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Affiliation(s)
- Eloise Keeling
- Clinical and Experimental Sciences, Faculty of Medicine, University of Southampton, MP806, Tremona Road, Southampton SO16 6YD, UK.
| | - Andrew J Lotery
- Clinical and Experimental Sciences, Faculty of Medicine, University of Southampton, MP806, Tremona Road, Southampton SO16 6YD, UK.
- Eye Unit, University Hospital Southampton NHS Foundation Trust, Southampton SO16 6YD, UK.
| | - David A Tumbarello
- Biological Sciences, Faculty of Natural & Environmental Sciences, Life Science Building 85, University of Southampton, Highfield Campus, Southampton SO17 1BJ, UK.
| | - J Arjuna Ratnayaka
- Clinical and Experimental Sciences, Faculty of Medicine, University of Southampton, MP806, Tremona Road, Southampton SO16 6YD, UK.
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21
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Age-Related Macular Degeneration: New Paradigms for Treatment and Management of AMD. OXIDATIVE MEDICINE AND CELLULAR LONGEVITY 2018; 2018:8374647. [PMID: 29484106 PMCID: PMC5816845 DOI: 10.1155/2018/8374647] [Citation(s) in RCA: 145] [Impact Index Per Article: 24.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/29/2017] [Accepted: 12/06/2017] [Indexed: 12/03/2022]
Abstract
Age-related macular degeneration (AMD) is a well-characterized and extensively studied disease. It is currently considered the leading cause of visual disability among patients over 60 years. The hallmark of early AMD is the formation of drusen, pigmentary changes at the macula, and mild to moderate vision loss. There are two forms of AMD: the “dry” and the “wet” form that is less frequent but is responsible for 90% of acute blindness due to AMD. Risk factors have been associated with AMD progression, and they are taking relevance to understand how AMD develops: (1) advanced age and the exposition to environmental factors inducing high levels of oxidative stress damaging the macula and (2) this damage, which causes inflammation inducing a vicious cycle, altogether causing central vision loss. There is neither a cure nor treatment to prevent AMD. However, there are some treatments available for the wet form of AMD. This article will review some molecular and cellular mechanisms associated with the onset of AMD focusing on feasible treatments for each related factor in the development of this pathology such as vascular endothelial growth factor, oxidative stress, failure of the clearance of proteins and organelles, and glial cell dysfunction in AMD.
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22
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SLOH, a carbazole-based fluorophore, mitigates neuropathology and behavioral impairment in the triple-transgenic mouse model of Alzheimer's disease. Neuropharmacology 2018; 131:351-363. [PMID: 29309769 DOI: 10.1016/j.neuropharm.2018.01.003] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2017] [Revised: 12/08/2017] [Accepted: 01/02/2018] [Indexed: 01/23/2023]
Abstract
Alzheimer's disease (AD) is a progressive neurodegenerative dysfunction characterized by memory impairment and brings a heavy burden to old people both in developing and developed countries. Amyloid hypothesis reveals that aggregation and deposition of amyloid plaques are the cause of AD neurodegeneration. SLOH, a carbazole-based fluorophore, is reported to inhibit amyloid beta (Aβ) aggregation in vitro. In the current study, we intended to evaluate the protective effect of SLOH in a triple transgenic AD mouse model (3xTg-AD). 3xTg-AD (10-month-old) were treated with SLOH (0.5, 1 and 2 mg kg-1) for one month via intraperitoneal injection. After treatment, cognitive function was assessed by Morris Water Maze (MWM) and Y-maze tasks. In addition, biochemical estimations were used to examine the degree of Aβ deposition, tau hyperphosphorylation and neuroinflammation in the brains of 3xTg-AD mice. An in vitro study was conducted on human neuroblastoma (SH-SY5Y) cells to determine the activity of SLOH on tau and GSK-3β using western blot and immunofluorescence staining. One month treatment with SLOH significantly ameliorated memory impairments in 3xTg-AD mice in MWM and Y-maze tests. Moreover, SLOH treatment mitigated the level of amyloid plaques, tau hyperphosphorylation and neuroinflammation in the mouse brain. SLOH also reduced tau hyperphosphorylation and down-regulated GSK-3β activity in Aβ induced neurotoxic SH-SY5Y cells. The promising results in mitigating amyloid plaques, tau hyperphosphorylation, neuroinflammation and ameliorating cognitive deficits following one-month treatment suggest that SLOH could be a potential multi-target molecule for the AD treatment.
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23
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Ma KG, Lv J, Yang WN, Chang KW, Hu XD, Shi LL, Zhai WY, Zong HF, Qian YH. The p38 mitogen activated protein kinase regulates β-amyloid protein internalization through the α7 nicotinic acetylcholine receptor in mouse brain. Brain Res Bull 2017; 137:41-52. [PMID: 29128415 DOI: 10.1016/j.brainresbull.2017.11.006] [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: 09/15/2017] [Revised: 11/01/2017] [Accepted: 11/07/2017] [Indexed: 12/29/2022]
Abstract
Alzheimer's disease (AD) is one of the most devastating neurodegenerative disorders. Intracellular β-amyloid protein (Aβ) is an early event in AD. It induces the formation of amyloid plaques and neuron damage. The α7 nicotinic acetylcholine receptor (α7nAChR) has been suggested to play an important role in Aβ caused cognition. It has high affinity with Aβ and could mediate Aβ internalization in vitro. However, whether in mouse brain the p38 MAPK signaling pathway is involved in the regulation of the α7nAChR mediated Aβ internalization and their role in mitochondria remains little known. Therefore, in this study, we revealed that Aβ is internalized by cholinergic and GABAergic neurons. The internalized Aβ were found deposits in lysosomes/endosomes and mitochondria. Aβ could form Aβ-α7nAChR complex with α7nAChR, activates the p38 mitogen activated protein kinase (MAPK). And the increasing of α7nAChR could in return mediate Aβ internalization in the cortex and hippocampus. In addition, by using the α7nAChR agonist PNU282987, the p38 phosphorylation level decreases, rescues the biochemical changes which are tightly associated with Aβ-induced apoptosis, such as Bcl2/Bax level, cytochrome c (Cyt c) release. Collectively, the p38 MAPK signaling pathway could regulate the α7nAChR-mediated internalization of Aβ. The activation of α7nAChR or the inhibition of p38 MAPK signaling pathway may be a beneficial therapy to AD.
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Affiliation(s)
- Kai-Ge Ma
- Department of Human Anatomy, Histology and Embryology, School of Basic Medical Sciences, Xi'an Jiaotong University Health Science Center, 76 Yanta West Road, Xi'an, 710061, China
| | - Jia Lv
- Department of Nephrology, First Affiliated Hospital of Xi'an Jiaotong University, 277 Yanta West Road, Xi'an, 710061, China
| | - Wei-Na Yang
- Department of Human Anatomy, Histology and Embryology, School of Basic Medical Sciences, Xi'an Jiaotong University Health Science Center, 76 Yanta West Road, Xi'an, 710061, China; Key Laboratory of Environment and Genes Related to Diseases (Xi'an Jiaotong University), Ministry of Education of China, Xi'an Jiaotong University Health Science Center, 76 Yanta West Road, Xi'an, 710061, China
| | - Ke-Wei Chang
- Department of Human Anatomy, Histology and Embryology, School of Basic Medical Sciences, Xi'an Jiaotong University Health Science Center, 76 Yanta West Road, Xi'an, 710061, China
| | - Xiao-Dan Hu
- Department of Human Anatomy, Histology and Embryology, School of Basic Medical Sciences, Xi'an Jiaotong University Health Science Center, 76 Yanta West Road, Xi'an, 710061, China; Key Laboratory of Environment and Genes Related to Diseases (Xi'an Jiaotong University), Ministry of Education of China, Xi'an Jiaotong University Health Science Center, 76 Yanta West Road, Xi'an, 710061, China
| | - Li-Li Shi
- Department of Human Anatomy, Xi'an Medical University, 1 Xinwang road, Xi'an, 710021, China
| | - Wan-Ying Zhai
- Department of Human Anatomy, Histology and Embryology, School of Basic Medical Sciences, Xi'an Jiaotong University Health Science Center, 76 Yanta West Road, Xi'an, 710061, China
| | - Hang-Fan Zong
- Department of Human Anatomy, Histology and Embryology, School of Basic Medical Sciences, Xi'an Jiaotong University Health Science Center, 76 Yanta West Road, Xi'an, 710061, China
| | - Yi-Hua Qian
- Department of Human Anatomy, Histology and Embryology, School of Basic Medical Sciences, Xi'an Jiaotong University Health Science Center, 76 Yanta West Road, Xi'an, 710061, China; Key Laboratory of Environment and Genes Related to Diseases (Xi'an Jiaotong University), Ministry of Education of China, Xi'an Jiaotong University Health Science Center, 76 Yanta West Road, Xi'an, 710061, China.
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24
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Ford L, Crossley M, Vadukul DM, Kemenes G, Serpell LC. Structure-dependent effects of amyloid-β on long-term memory in Lymnaea stagnalis. FEBS Lett 2017; 591:1236-1246. [PMID: 28337747 PMCID: PMC5435943 DOI: 10.1002/1873-3468.12633] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2016] [Revised: 02/24/2017] [Accepted: 03/20/2017] [Indexed: 12/03/2022]
Abstract
Amyloid‐β (Aβ) peptides are implicated in the causation of memory loss, neuronal impairment, and neurodegeneration in Alzheimer's disease. Our recent work revealed that Aβ 1–42 and Aβ 25–35 inhibit long‐term memory (LTM) recall in Lymnaea stagnalis (pond snail) in the absence of cell death. Here, we report the characterization of the active species prepared under different conditions, describe which Aβ species is present in brain tissue during the behavioral recall time point and relate the sequence and structure of the oligomeric species to the resulting neuronal properties and effect on LTM. Our results suggest that oligomers are the key toxic Aβ1–42 structures, which likely affect LTM through synaptic plasticity pathways, and that Aβ 1–42 and Aβ 25–35 cannot be used as interchangeable peptides.
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Affiliation(s)
- Lenzie Ford
- Sussex NeuroscienceSchool of Life SciencesUniversity of SussexBrightonUK
- Present address: Department of NeuroscienceColumbia UniversityNew YorkNY10032USA
- Present address: Howard Hughes Medical InstituteColumbia UniversityNew YorkNY10032USA
| | - Michael Crossley
- Sussex NeuroscienceSchool of Life SciencesUniversity of SussexBrightonUK
| | - Devkee M. Vadukul
- Sussex NeuroscienceSchool of Life SciencesUniversity of SussexBrightonUK
| | - György Kemenes
- Sussex NeuroscienceSchool of Life SciencesUniversity of SussexBrightonUK
| | - Louise C. Serpell
- Sussex NeuroscienceSchool of Life SciencesUniversity of SussexBrightonUK
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25
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Wu X, Kosaraju J, Zhou W, Tam KY. Neuroprotective Effect of SLM, a Novel Carbazole-Based Fluorophore, on SH-SY5Y Cell Model and 3xTg-AD Mouse Model of Alzheimer's Disease. ACS Chem Neurosci 2017; 8:676-685. [PMID: 28032988 DOI: 10.1021/acschemneuro.6b00388] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
Amyloid β (Aβ) peptide aggregating to form a neurotoxic plaque, leading to cognitive deficits, is believed to be one of the plausible mechanisms for Alzheimer's disease (AD). Inhibiting Aβ aggregation is supposed to offer a neuroprotective effect to ameliorate AD. A previous report has shown that SLM, a carbazole-based fluorophore, binds to Aβ to inhibit the aggregation. However, it is not entirely clear whether the inhibition of Aβ aggregation alone would lead to the anticipated neuroprotective effects. In the current study, we intended to examine the protective action of SLM against Aβ-induced neurotoxicity in vitro and to evaluate if SLM can decrease the cognitive and behavioral deficits observed in triple transgenic AD mouse model (3xTg-AD). In the in vitro study, neurotoxicity induced by Aβ42 in human neuroblastoma (SH-SY5Y) cells was found to be reduced through the treatment with SLM. In the in vivo study, following one month SLM intraperitoneal injection (1, 2, and 4 mg/kg), 3xTg-AD mice were tested on Morris water maze (MWM) and Y-maze for their cognitive ability and sacrificed for biochemical estimations. Results show that SLM treatment improved the learning and memory ability in 3xTg-AD mice in MWM and Y-maze tasks. SLM also mitigated the amyloid burden by decreasing brain Aβ40 and Aβ42 levels and reduced tau phosphorylation, glycogen synthase kinase-3β activity, and neuro-inflammation. From our observations, SLM shows neuroprotection in SH-SY5Y cells against Aβ42 and also in 3xTg-AD mouse model by mitigating the pathological features and behavioral impairments.
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Affiliation(s)
- Xiaoli Wu
- Drug Development Core, Faculty
of Health Sciences, University of Macau, Taipa, Macau, China
| | - Jayasankar Kosaraju
- Drug Development Core, Faculty
of Health Sciences, University of Macau, Taipa, Macau, China
| | - Wei Zhou
- Drug Development Core, Faculty
of Health Sciences, University of Macau, Taipa, Macau, China
| | - Kin Yip Tam
- Drug Development Core, Faculty
of Health Sciences, University of Macau, Taipa, Macau, China
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26
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Vadukul DM, Gbajumo O, Marshall KE, Serpell LC. Amyloidogenicity and toxicity of the reverse and scrambled variants of amyloid-β 1-42. FEBS Lett 2017; 591:822-830. [PMID: 28185264 PMCID: PMC5363225 DOI: 10.1002/1873-3468.12590] [Citation(s) in RCA: 38] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2016] [Revised: 01/17/2017] [Accepted: 02/05/2017] [Indexed: 12/29/2022]
Abstract
β‐amyloid 1‐42 (Aβ1‐42) is a self‐assembling peptide that goes through many conformational and morphological changes before forming the fibrils that are deposited in extracellular plaques characteristic of Alzheimer's disease. The link between Aβ1‐42 structure and toxicity is of major interest, in particular, the neurotoxic potential of oligomeric species. Many studies utilise reversed (Aβ42‐1) and scrambled (AβS) forms of amyloid‐β as control peptides. Here, using circular dichroism, thioflavin T fluorescence and transmission electron microscopy, we reveal that both control peptides self‐assemble to form fibres within 24 h. However, oligomeric Aβ reduces cell survival of hippocampal neurons, while Aβ42‐1 and Aβs have reduced effect on cellular health, which may arise from their ability to assemble rapidly to form protofibrils and fibrils.
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27
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Lynn SA, Keeling E, Munday R, Gabha G, Griffiths H, Lotery AJ, Ratnayaka JA. The complexities underlying age-related macular degeneration: could amyloid beta play an important role? Neural Regen Res 2017; 12:538-548. [PMID: 28553324 PMCID: PMC5436342 DOI: 10.4103/1673-5374.205083] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022] Open
Abstract
Age-related macular degeneration (AMD) causes irreversible loss of central vision for which there is no effective treatment. Incipient pathology is thought to occur in the retina for many years before AMD manifests from midlife onwards to affect a large proportion of the elderly. Although genetic as well as non-genetic/environmental risks are recognized, its complex aetiology makes it difficult to identify susceptibility, or indeed what type of AMD develops or how quickly it progresses in different individuals. Here we summarize the literature describing how the Alzheimer's-linked amyloid beta (Aβ) group of misfolding proteins accumulate in the retina. The discovery of this key driver of Alzheimer's disease in the senescent retina was unexpected and surprising, enabling an altogether different perspective of AMD. We argue that Aβ fundamentally differs from other substances which accumulate in the ageing retina, and discuss our latest findings from a mouse model in which physiological amounts of Aβ were subretinally-injected to recapitulate salient features of early AMD within a short period. Our discoveries as well as those of others suggest the pattern of Aβ accumulation and pathology in donor aged/AMD tissues are closely reproduced in mice, including late-stage AMD phenotypes, which makes them highly attractive to study dynamic aspects of Aβ-mediated retinopathy. Furthermore, we discuss our findings revealing how Aβ behaves at single-cell resolution, and consider the long-term implications for neuroretinal function. We propose Aβ as a key element in switching to a diseased retinal phenotype, which is now being used as a biomarker for late-stage AMD.
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Affiliation(s)
- Savannah A Lynn
- Clinical and Experimental Sciences, Faculty of Medicine, University of Southampton, Southampton, United Kingdom
| | - Eloise Keeling
- Clinical and Experimental Sciences, Faculty of Medicine, University of Southampton, Southampton, United Kingdom
| | - Rosie Munday
- Clinical and Experimental Sciences, Faculty of Medicine, University of Southampton, Southampton, United Kingdom
| | - Gagandeep Gabha
- Clinical and Experimental Sciences, Faculty of Medicine, University of Southampton, Southampton, United Kingdom
| | - Helen Griffiths
- Clinical and Experimental Sciences, Faculty of Medicine, University of Southampton, Southampton, United Kingdom
| | - Andrew J Lotery
- Clinical and Experimental Sciences, Faculty of Medicine, University of Southampton, Southampton, United Kingdom.,Eye Unit, University Southampton NHS Trust, Southampton, United Kingdom
| | - J Arjuna Ratnayaka
- Clinical and Experimental Sciences, Faculty of Medicine, University of Southampton, Southampton, United Kingdom
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28
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Taylor-Walker G, Lynn SA, Keeling E, Munday R, Johnston DA, Page A, Scott JA, Goverdhan S, Lotery AJ, Ratnayaka JA. The Alzheimer's-related amyloid beta peptide is internalised by R28 neuroretinal cells and disrupts the microtubule associated protein 2 (MAP-2). Exp Eye Res 2016; 153:110-121. [PMID: 27751744 PMCID: PMC5131630 DOI: 10.1016/j.exer.2016.10.013] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2016] [Revised: 09/12/2016] [Accepted: 10/11/2016] [Indexed: 11/15/2022]
Abstract
Age-related Macular Degeneration (AMD) is a common, irreversible blinding condition that leads to the loss of central vision. AMD has a complex aetiology with both genetic as well as environmental risks factors, and share many similarities with Alzheimer's disease. Recent findings have contributed significantly to unravelling its genetic architecture that is yet to be matched by molecular insights. Studies are made more challenging by observations that aged and AMD retinas accumulate the highly pathogenic Alzheimer's-related Amyloid beta (Aβ) group of peptides, for which there appears to be no clear genetic basis. Analyses of human donor and animal eyes have identified retinal Aβ aggregates in retinal ganglion cells (RGC), the inner nuclear layer, photoreceptors as well as the retinal pigment epithelium. Aβ is also a major drusen constituent; found correlated with elevated drusen-load and age, with a propensity to aggregate in retinas of advanced AMD. Despite this evidence, how such a potent driver of neurodegeneration might impair the neuroretina remains incompletely understood, and studies into this important aspect of retinopathy remains limited. In order to address this we exploited R28 rat retinal cells which due to its heterogeneous nature, offers diverse neuroretinal cell-types in which to study the molecular pathology of Aβ. R28 cells are also unaffected by problems associated with the commonly used RGC-5 immortalised cell-line, thus providing a well-established model in which to study dynamic Aβ effects at single-cell resolution. Our findings show that R28 cells express key neuronal markers calbindin, protein kinase C and the microtubule associated protein-2 (MAP-2) by confocal immunofluorescence which has not been shown before, but also calretinin which has not been reported previously. For the first time, we reveal that retinal neurons rapidly internalised Aβ1-42, the most cytotoxic and aggregate-prone amongst the Aβ family. Furthermore, exposure to physiological amounts of Aβ1-42 for 24 h correlated with impairment to neuronal MAP-2, a cytoskeletal protein which regulates microtubule dynamics in axons and dendrites. Disruption to MAP-2 was transient, and had recovered by 48 h, although internalised Aβ persisted as discrete puncta for as long as 72 h. To assess whether Aβ could realistically localise to living retinas to mediate such effects, we subretinally injected nanomolar levels of oligomeric Aβ1-42 into wildtype mice. Confocal microscopy revealed the presence of focal Aβ deposits in RGC, the inner nuclear and the outer plexiform layers 8 days later, recapitulating naturally-occurring patterns of Aβ aggregation in aged retinas. Our novel findings describe how retinal neurons internalise Aβ to transiently impair MAP-2 in a hitherto unreported manner. MAP-2 dysfunction is reported in AMD retinas, and is thought to be involved in remodelling and plasticity of post-mitotic neurons. Our insights suggest a molecular pathway by which this could occur in the senescent eye leading to complex diseases such as AMD. Molecular basis of complex retinopathies such as AMD is incompletely understood. The Alzheimer's-related Aβ peptides are rapidly internalised by retinal neurons. Internalised Aβ is retained within neurons and transiently impairs MAP-2. Subretinally injected Aβ mimics its naturally-occurring distribution in aged retinas.
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Affiliation(s)
- George Taylor-Walker
- Clinical and Experimental Sciences, Faculty of Medicine, University of Southampton, SGH, MP806, Tremona Road, Southampton, SO16 6YD, United Kingdom
| | - Savannah A Lynn
- Clinical and Experimental Sciences, Faculty of Medicine, University of Southampton, SGH, MP806, Tremona Road, Southampton, SO16 6YD, United Kingdom
| | - Eloise Keeling
- Clinical and Experimental Sciences, Faculty of Medicine, University of Southampton, SGH, MP806, Tremona Road, Southampton, SO16 6YD, United Kingdom
| | - Rosie Munday
- Clinical and Experimental Sciences, Faculty of Medicine, University of Southampton, SGH, MP806, Tremona Road, Southampton, SO16 6YD, United Kingdom
| | - David A Johnston
- Biomedical Imaging Unit, University of Southampton, SGH, MP12, Tremona Road, Southampton, SO16 6YD, United Kingdom
| | - Anton Page
- Biomedical Imaging Unit, University of Southampton, SGH, MP12, Tremona Road, Southampton, SO16 6YD, United Kingdom
| | - Jennifer A Scott
- Clinical and Experimental Sciences, Faculty of Medicine, University of Southampton, SGH, MP806, Tremona Road, Southampton, SO16 6YD, United Kingdom
| | - Srini Goverdhan
- Clinical and Experimental Sciences, Faculty of Medicine, University of Southampton, SGH, MP806, Tremona Road, Southampton, SO16 6YD, United Kingdom
| | - Andrew J Lotery
- Clinical and Experimental Sciences, Faculty of Medicine, University of Southampton, SGH, MP806, Tremona Road, Southampton, SO16 6YD, United Kingdom; Eye Unit, University Southampton NHS Trust, Southampton, SO16 6YD, United Kingdom
| | - J Arjuna Ratnayaka
- Clinical and Experimental Sciences, Faculty of Medicine, University of Southampton, SGH, MP806, Tremona Road, Southampton, SO16 6YD, United Kingdom.
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29
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Marshall KE, Vadukul DM, Dahal L, Theisen A, Fowler MW, Al-Hilaly Y, Ford L, Kemenes G, Day IJ, Staras K, Serpell LC. A critical role for the self-assembly of Amyloid-β1-42 in neurodegeneration. Sci Rep 2016; 6:30182. [PMID: 27443509 PMCID: PMC4957119 DOI: 10.1038/srep30182] [Citation(s) in RCA: 48] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2016] [Accepted: 06/28/2016] [Indexed: 11/23/2022] Open
Abstract
Amyloid β1-42 (Aβ1-42) plays a central role in Alzheimer’s disease. The link between structure, assembly and neuronal toxicity of this peptide is of major current interest but still poorly defined. Here, we explored this relationship by rationally designing a variant form of Aβ1-42 (vAβ1-42) differing in only two amino acids. Unlike Aβ1-42, we found that the variant does not self-assemble, nor is it toxic to neuronal cells. Moreover, while Aβ1-42 oligomers impact on synaptic function, vAβ1-42 does not. In a living animal model system we demonstrate that only Aβ1-42 leads to memory deficits. Our findings underline a key role for peptide sequence in the ability to assemble and form toxic structures. Furthermore, our non-toxic variant satisfies an unmet demand for a closely related control peptide for Aβ1-42 cellular studies of disease pathology, offering a new opportunity to decipher the mechanisms that accompany Aβ1-42-induced toxicity leading to neurodegeneration.
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Affiliation(s)
- Karen E Marshall
- School of Life Sciences, University of Sussex, Falmer, BN1 9QG, UK
| | - Devkee M Vadukul
- School of Life Sciences, University of Sussex, Falmer, BN1 9QG, UK
| | - Liza Dahal
- School of Life Sciences, University of Sussex, Falmer, BN1 9QG, UK
| | - Alina Theisen
- School of Life Sciences, University of Sussex, Falmer, BN1 9QG, UK
| | - Milena W Fowler
- School of Life Sciences, University of Sussex, Falmer, BN1 9QG, UK
| | - Youssra Al-Hilaly
- School of Life Sciences, University of Sussex, Falmer, BN1 9QG, UK.,College of Sciences, Chemistry Department, Al-Mustansiriyah University, Baghdad, Iraq
| | - Lenzie Ford
- School of Life Sciences, University of Sussex, Falmer, BN1 9QG, UK
| | - György Kemenes
- School of Life Sciences, University of Sussex, Falmer, BN1 9QG, UK
| | - Iain J Day
- School of Life Sciences, University of Sussex, Falmer, BN1 9QG, UK
| | - Kevin Staras
- School of Life Sciences, University of Sussex, Falmer, BN1 9QG, UK
| | - Louise C Serpell
- School of Life Sciences, University of Sussex, Falmer, BN1 9QG, UK
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Williams TL, Choi JK, Surewicz K, Surewicz WK. Soluble Prion Protein Binds Isolated Low Molecular Weight Amyloid-β Oligomers Causing Cytotoxicity Inhibition. ACS Chem Neurosci 2015; 6:1972-80. [PMID: 26466138 DOI: 10.1021/acschemneuro.5b00229] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
A growing number of observations indicate that soluble amyloid-β (Aβ) oligomers play a major role in Alzheimer's disease. Recent studies strongly suggest that at least some of the neurotoxic effects of these oligomers are mediated by cellular, membrane-anchored prion protein and that Aβ neurotoxicity can be inhibited by soluble recombinant prion protein (rPrP) and its fragments. However, the mechanism by which rPrP interacts with Aβ oligomers and prevents their toxicity is largely unknown, and studies in this regard are hindered by the large structural heterogeneity of Aβ oligomers. To overcome this difficulty, here we used photoinduced cross-linking of unmodified proteins (PICUP) to isolate well-defined oligomers of Aβ42 and characterize these species with regard to their cytotoxicity and interaction with rPrP, as well the mechanism by which rPrP inhibits Aβ42 cytotoxicity. Our data shows that the addition of rPrP to the assembling Aβ42 results in a shift in oligomer size distribution, decreasing the population of toxic tetramers and higher order oligomers and increasing the population of nontoxic (and possibly neuroprotective) monomers. Isolated oligomeric species of Aβ42 are cytotoxic to primary neurons and cause permeation of model lipid bilayers. These toxic effects, which are oligomer size-dependent, can be inhibited by the addition of rPrP, and our data suggest potential mechanisms of this inhibitory action. This insight should help in current efforts to develop PrP-based therapeutics for Alzheimer's disease.
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Affiliation(s)
- Thomas L. Williams
- Department of Physiology and Biophysics, Case Western Reserve University, Cleveland, Ohio 44106, United States
| | - Jin-Kyu Choi
- Department of Physiology and Biophysics, Case Western Reserve University, Cleveland, Ohio 44106, United States
| | - Krystyna Surewicz
- Department of Physiology and Biophysics, Case Western Reserve University, Cleveland, Ohio 44106, United States
| | - Witold K. Surewicz
- Department of Physiology and Biophysics, Case Western Reserve University, Cleveland, Ohio 44106, United States
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Williams TL, Serpell LC, Urbanc B. Stabilization of native amyloid β-protein oligomers by Copper and Hydrogen peroxide Induced Cross-linking of Unmodified Proteins (CHICUP). BIOCHIMICA ET BIOPHYSICA ACTA-PROTEINS AND PROTEOMICS 2015; 1864:249-259. [PMID: 26699836 DOI: 10.1016/j.bbapap.2015.12.001] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/31/2015] [Revised: 11/09/2015] [Accepted: 12/01/2015] [Indexed: 12/17/2022]
Abstract
Oligomeric assemblies are postulated to be proximate neurotoxic species in human diseases associated with aberrant protein aggregation. Their heterogeneous and transient nature makes their structural characterization difficult. Size distributions of oligomers of several amyloidogenic proteins, including amyloid β-protein (Aβ) relevant to Alzheimer's disease (AD), have been previously characterized in vitro by photo-induced cross-linking of unmodified proteins (PICUP) followed by sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE). Due to non-physiological conditions associated with the PICUP chemistry, Aβ oligomers cross-linked by PICUP may not be representative of in vivo conditions. Here, we examine an alternative Copper and Hydrogen peroxide Induced Cross-linking of Unmodified Proteins (CHICUP), which utilizes naturally occurring divalent copper ions and hydrogen peroxide and does not require photo activation. Our results demonstrate that CHICUP and PICUP applied to the two predominant Aβ alloforms, Aβ40 and Aβ42, result in similar oligomer size distributions. Thioflavin T fluorescence data and atomic force microscopy images demonstrate that both CHICUP and PICUP stabilize Aβ oligomers and attenuate fibril formation. Relative to noncross-linked peptides, CHICUP-treated Aβ40 and Aβ42 cause prolonged disruption to biomimetic lipid vesicles. CHICUP-stabilized Aβ oligomers link the amyloid cascade, metal, and oxidative stress hypotheses of AD into a more comprehensive understanding of the molecular basis of AD pathology. Because copper and hydrogen peroxide are elevated in the AD brain, CHICUP-stabilized Aβ oligomers are biologically relevant and should be further explored as a new therapeutic target.
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Affiliation(s)
- Thomas L Williams
- Department of Physics, Drexel University, Philadelphia, PA 19104, USA
| | - Louise C Serpell
- School of Life Sciences, University of Sussex, Falmer, East Sussex, UK
| | - Brigita Urbanc
- Department of Physics, Drexel University, Philadelphia, PA 19104, USA; Faculty of Mathematics and Physics, University of Ljubljana, Slovenia.
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The unfolded protein response in the therapeutic effect of hydroxy-DHA against Alzheimer's disease. Apoptosis 2015; 20:712-24. [PMID: 25663172 DOI: 10.1007/s10495-015-1099-z] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
The unfolded protein response (UPR) and autophagy are two cellular processes involved in the clearing of intracellular misfolded proteins. Both pathways are targets for molecules that may serve as treatments for several diseases, including neurodegenerative disorders like Alzheimer's disease (AD). In the present work, we show that 2-hydroxy-DHA (HDHA), a docosahexaenoic acid (DHA) derivate that restores cognitive function in a transgenic mouse model of AD, modulates UPR and autophagy in differentiated neuron-like SH-SY5Y cells. Mild therapeutic HDHA exposure induced UPR activation, characterized by the up-regulation of the molecular chaperone Bip as well as PERK-mediated stimulation of eIF2α phosphorylation. Key proteins involved in initiating autophagy, such as beclin-1, and several Atg proteins involved in autophagosome maturation (Atg3, Atg5, Atg12 and Atg7), were also up-regulated on exposure to HDHA. Moreover, when HDHA-mediated autophagy was studied after amyloid-β peptide (Aβ) stimulation to mimic the neurotoxic environment of AD, it was associated with increased cell survival, suggesting that HDHA driven modulation of this process at least in part mediates the neuroprotective effects of this new anti-neurodegenerative drug. The present results in part explain the pharmacological effects of HDHA inducing full recovery of the cognitive scores in murine models of AD.
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Choi S, Kim D, Kam TI, Yun S, Kim S, Park H, Hwang H, Pletnikova O, Troncoso JC, Dawson VL, Dawson TM, Ko HS. Lysosomal Enzyme Glucocerebrosidase Protects against Aβ1-42 Oligomer-Induced Neurotoxicity. PLoS One 2015; 10:e0143854. [PMID: 26629917 PMCID: PMC4668030 DOI: 10.1371/journal.pone.0143854] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2015] [Accepted: 11/10/2015] [Indexed: 01/31/2023] Open
Abstract
Glucocerebrosidase (GCase) functions as a lysosomal enzyme and its mutations are known to be related to many neurodegenerative diseases, including Gaucher’s disease (GD), Parkinson’s disease (PD), and Dementia with Lewy Bodies (DLB). However, there is little information about the role of GCase in the pathogenesis of Alzheimer’s disease (AD). Here we demonstrate that GCase protein levels and enzyme activity are significantly decreased in sporadic AD. Moreover, Aβ1–42 oligomer treatment results in neuronal cell death that is concomitant with decreased GCase protein levels and enzyme activity, as well as impairment in lysosomal biogenesis and acidification. Importantly, overexpression of GCase promotes the lysosomal degradation of Aβ1–42 oligomers, restores the lysosomal impairment, and protects against the toxicity in neurons treated with Aβ1–42 oligomers. Our findings indicate that a deficiency of GCase could be involved in progression of AD pathology and suggest that augmentation of GCase activity may be a potential therapeutic option for the treatment of AD.
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Affiliation(s)
- Seulah Choi
- Neuroregeneration and Stem Cell Programs, Institute for Cell Engineering, The Johns Hopkins University School of Medicine, Baltimore, Maryland, United States of America
- Department of Neurology, The Johns Hopkins University School of Medicine, Baltimore, Maryland, United States of America
- Diana Helis Henry Medical Research Foundation, New Orleans, Louisiana, United States of America
| | - Donghoon Kim
- Neuroregeneration and Stem Cell Programs, Institute for Cell Engineering, The Johns Hopkins University School of Medicine, Baltimore, Maryland, United States of America
- Department of Neurology, The Johns Hopkins University School of Medicine, Baltimore, Maryland, United States of America
- Diana Helis Henry Medical Research Foundation, New Orleans, Louisiana, United States of America
| | - Tae-In Kam
- Neuroregeneration and Stem Cell Programs, Institute for Cell Engineering, The Johns Hopkins University School of Medicine, Baltimore, Maryland, United States of America
- Department of Neurology, The Johns Hopkins University School of Medicine, Baltimore, Maryland, United States of America
| | - Seungpil Yun
- Neuroregeneration and Stem Cell Programs, Institute for Cell Engineering, The Johns Hopkins University School of Medicine, Baltimore, Maryland, United States of America
- Department of Neurology, The Johns Hopkins University School of Medicine, Baltimore, Maryland, United States of America
- Adrienne Helis Malvin Medical Research Foundation, New Orleans, Louisiana, United States of America
| | - Sangjune Kim
- Neuroregeneration and Stem Cell Programs, Institute for Cell Engineering, The Johns Hopkins University School of Medicine, Baltimore, Maryland, United States of America
- Department of Neurology, The Johns Hopkins University School of Medicine, Baltimore, Maryland, United States of America
| | - Hyejin Park
- Neuroregeneration and Stem Cell Programs, Institute for Cell Engineering, The Johns Hopkins University School of Medicine, Baltimore, Maryland, United States of America
- Department of Neurology, The Johns Hopkins University School of Medicine, Baltimore, Maryland, United States of America
| | - Heehong Hwang
- Neuroregeneration and Stem Cell Programs, Institute for Cell Engineering, The Johns Hopkins University School of Medicine, Baltimore, Maryland, United States of America
| | - Olga Pletnikova
- Department of Pathology, The Johns Hopkins University School of Medicine, Baltimore, Maryland, United States of America
| | - Juan C. Troncoso
- Department of Neurology, The Johns Hopkins University School of Medicine, Baltimore, Maryland, United States of America
- Department of Pathology, The Johns Hopkins University School of Medicine, Baltimore, Maryland, United States of America
| | - Valina L. Dawson
- Neuroregeneration and Stem Cell Programs, Institute for Cell Engineering, The Johns Hopkins University School of Medicine, Baltimore, Maryland, United States of America
- Department of Neurology, The Johns Hopkins University School of Medicine, Baltimore, Maryland, United States of America
- Department of Physiology, The Johns Hopkins University School of Medicine, Baltimore, Maryland, United States of America
- Solomon H. Snyder Department of Neuroscience, The Johns Hopkins University School of Medicine, Baltimore, Maryland, United States of America
- Adrienne Helis Malvin Medical Research Foundation, New Orleans, Louisiana, United States of America
| | - Ted M. Dawson
- Neuroregeneration and Stem Cell Programs, Institute for Cell Engineering, The Johns Hopkins University School of Medicine, Baltimore, Maryland, United States of America
- Department of Neurology, The Johns Hopkins University School of Medicine, Baltimore, Maryland, United States of America
- Solomon H. Snyder Department of Neuroscience, The Johns Hopkins University School of Medicine, Baltimore, Maryland, United States of America
- Department of Pharmacology and Molecular Sciences, The Johns Hopkins University School of Medicine, Baltimore, Maryland, United States of America
- Adrienne Helis Malvin Medical Research Foundation, New Orleans, Louisiana, United States of America
| | - Han Seok Ko
- Neuroregeneration and Stem Cell Programs, Institute for Cell Engineering, The Johns Hopkins University School of Medicine, Baltimore, Maryland, United States of America
- Department of Neurology, The Johns Hopkins University School of Medicine, Baltimore, Maryland, United States of America
- Diana Helis Henry Medical Research Foundation, New Orleans, Louisiana, United States of America
- * E-mail:
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Williams TL, Urbanc B, Marshall KE, Vadukul DM, Jenkins ATA, Serpell LC. Europium as an inhibitor of Amyloid-β(1-42) induced membrane permeation. FEBS Lett 2015; 589:3228-36. [PMID: 26450778 PMCID: PMC4641243 DOI: 10.1016/j.febslet.2015.09.027] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2015] [Revised: 09/16/2015] [Accepted: 09/25/2015] [Indexed: 11/25/2022]
Abstract
Europium ions complex with GM1 gangliosides in phospholipid membranes. Europium ions cause inhibition Aβ–membrane interactions. Europium blocks an Aβ receptor protecting against membrane permeation. Discrete Aβ binding events correlate to specific membrane permeation events.
Soluble Amyloid-beta (Aβ) oligomers are a source of cytotoxicity in Alzheimer’s disease (AD). The toxicity of Aβ oligomers may arise from their ability to interact with and disrupt cellular membranes mediated by GM1 ganglioside receptors within these membranes. Therefore, inhibition of Aβ–membrane interactions could provide a means of preventing the toxicity associated with Aβ. Here, using Surface Plasmon field-enhanced Fluorescence Spectroscopy, we determine that the lanthanide, Europium III chloride (Eu3+), strongly binds to GM1 ganglioside-containing membranes and prevents the interaction with Aβ42 leading to a loss of the peptides ability to cause membrane permeation. Here we discuss the molecular mechanism by which Eu3+ inhibits Aβ42-membrane interactions and this may lead to protection of membrane integrity against Aβ42 induced toxicity.
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Affiliation(s)
- Thomas L Williams
- School of Life Sciences, University of Sussex, Falmer, East Sussex BN1 9QG, UK; Physics Department, Drexel University, Philadelphia, PA 19104, USA; School of Medicine, Case Western Reserve University, Cleveland, OH 44106, USA.
| | - Brigita Urbanc
- Physics Department, Drexel University, Philadelphia, PA 19104, USA
| | - Karen E Marshall
- School of Life Sciences, University of Sussex, Falmer, East Sussex BN1 9QG, UK
| | - Devkee M Vadukul
- School of Life Sciences, University of Sussex, Falmer, East Sussex BN1 9QG, UK
| | | | - Louise C Serpell
- School of Life Sciences, University of Sussex, Falmer, East Sussex BN1 9QG, UK.
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Ratnayaka JA, Serpell LC, Lotery AJ. Dementia of the eye: the role of amyloid beta in retinal degeneration. Eye (Lond) 2015; 29:1013-26. [PMID: 26088679 PMCID: PMC4541342 DOI: 10.1038/eye.2015.100] [Citation(s) in RCA: 116] [Impact Index Per Article: 12.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2015] [Accepted: 04/23/2015] [Indexed: 11/09/2022] Open
Abstract
Age-related macular degeneration (AMD) is one of the most common causes of irreversible blindness affecting nearly 50 million individuals globally. The disease is characterised by progressive loss of central vision, which has significant implications for quality of life concerns in an increasingly ageing population. AMD pathology manifests in the macula, a specialised region of the retina, which is responsible for central vision and perception of fine details. The underlying pathology of this complex degenerative disease is incompletely understood but includes both genetic as well as epigenetic risk factors. The recent discovery that amyloid beta (Aβ), a highly toxic and aggregate-prone family of peptides, is elevated in the ageing retina and is associated with AMD has opened up new perspectives on the aetiology of this debilitating blinding disease. Multiple studies now link Aβ with key stages of AMD progression, which is both exciting and potentially insightful, as this identifies a well-established toxic agent that aggressively targets cells in degenerative brains. Here, we review the most recent findings supporting the hypothesis that Aβ may be a key factor in AMD pathology. We describe how multiple Aβ reservoirs, now reported in the ageing eye, may target the cellular physiology of the retina as well as associated layers, and propose a mechanistic pathway of Aβ-mediated degenerative change leading to AMD.
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Affiliation(s)
- J A Ratnayaka
- Clinical and Experimental Science, Faculty of Medicine, University of Southampton, Southampton, UK
| | - L C Serpell
- School of Life Sciences (Biochemistry, Dementia Research Group), University of Sussex, Brighton, UK
| | - A J Lotery
- Clinical and Experimental Science, Faculty of Medicine, University of Southampton, Southampton, UK
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Ford L, Crossley M, Williams T, Thorpe JR, Serpell LC, Kemenes G. Effects of Aβ exposure on long-term associative memory and its neuronal mechanisms in a defined neuronal network. Sci Rep 2015; 5:10614. [PMID: 26024049 PMCID: PMC4448550 DOI: 10.1038/srep10614] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2014] [Accepted: 04/21/2015] [Indexed: 12/02/2022] Open
Abstract
Amyloid beta (Aβ) induced neuronal death has been linked to memory loss, perhaps the most devastating symptom of Alzheimer’s disease (AD). Although Aβ-induced impairment of synaptic or intrinsic plasticity is known to occur before any cell death, the links between these neurophysiological changes and the loss of specific types of behavioral memory are not fully understood. Here we used a behaviorally and physiologically tractable animal model to investigate Aβ-induced memory loss and electrophysiological changes in the absence of neuronal death in a defined network underlying associative memory. We found similar behavioral but different neurophysiological effects for Aβ 25-35 and Aβ 1-42 in the feeding circuitry of the snail Lymnaea stagnalis. Importantly, we also established that both the behavioral and neuronal effects were dependent upon the animals having been classically conditioned prior to treatment, since Aβ application before training caused neither memory impairment nor underlying neuronal changes over a comparable period of time following treatment.
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Affiliation(s)
- Lenzie Ford
- Sussex Neuroscience, School of Life Sciences, University of Sussex, Brighton, BN1 9QG
| | - Michael Crossley
- Sussex Neuroscience, School of Life Sciences, University of Sussex, Brighton, BN1 9QG
| | - Thomas Williams
- Sussex Neuroscience, School of Life Sciences, University of Sussex, Brighton, BN1 9QG
| | - Julian R Thorpe
- Sussex Neuroscience, School of Life Sciences, University of Sussex, Brighton, BN1 9QG
| | - Louise C Serpell
- Sussex Neuroscience, School of Life Sciences, University of Sussex, Brighton, BN1 9QG
| | - György Kemenes
- Sussex Neuroscience, School of Life Sciences, University of Sussex, Brighton, BN1 9QG
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Roux C, Aligny C, Lesueur C, Girault V, Brunel V, Ramdani Y, Genty D, Driouich A, Laquerrière A, Marret S, Brasse-Lagnel C, Gonzalez BJ, Bekri S. NMDA receptor blockade in the developing cortex induces autophagy-mediated death of immature cortical GABAergic interneurons: An ex vivo and in vivo study in Gad67-GFP mice. Exp Neurol 2015; 267:177-93. [PMID: 25795167 DOI: 10.1016/j.expneurol.2015.02.037] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2014] [Revised: 01/14/2015] [Accepted: 02/05/2015] [Indexed: 01/16/2023]
Abstract
In neonates, excitotoxicity is a major process involved in hypoxic-ischemic brain lesions, and several research groups have suggested the use of NMDA antagonists for neuroprotection. However, despite their clinical interest, there is more and more evidence suggesting that, in the immature brain, these molecules exert deleterious actions on migrating GABAergic interneurons by suppressing glutamatergic trophic inputs. Consequently, preventing the side effects of NMDA antagonists would be therapeutically useful. Because macroautophagy is involved in the adaptive response to trophic deprivation, the aim of the present study was to investigate the impact of autophagy modulators on the MK801-induced death of immature GABAergic interneurons and to characterize the crosstalk between autophagic and apoptotic mechanisms in this cell type. Ex vivo, using cortical slices from NMRI and Gad67-GFP mice, we show that blockade of the NMDA receptor results in an accumulation of autophagosomes due to the disruption of the autophagic flux. This effect precedes the activation of the mitochondrial apoptotic pathway, and the degeneration of immature GABAergic neurons present in developing cortical layers II-IV and is prevented by 3-MA, an autophagy inhibitor. In contrast, modulators of autophagy (3-MA, rapamycin) do not interfere with the anti-excitotoxic and neuroprotective effect of MK801 observed in deep layers V and VI. In vivo, 3-MA blocks the rapid increase in caspase-3 cleavage induced by the blockade of NMDA receptors and prevents the resulting long-term decrease in Gad67-GFP neurons in layers II-IV. Together, these data suggest that, in the developing cortex, the suppression of glutamatergic inputs through NMDA receptor inhibition results in the impairment of the autophagic flux and the subsequent switch to apoptotic death of immature GABAergic interneurons. The concomitant inhibition of autophagy prevents this pro-apoptotic action of the NMDA blocker and favors the long-term rescue of GABAergic interneurons without interfering with its neuroprotective actions. The use of autophagy modulators in the developing brain would create new opportunities to prevent the side effects of NMDA antagonists used for neuroprotection or anesthesia.
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Affiliation(s)
- Christian Roux
- Region-Inserm Team NeoVasc ERI28, Laboratory of Microvascular Endothelium and Neonate Brain Lesions, Institute of Research for Innovation in Biomedicine, Normandy University, Rouen, France
| | - Caroline Aligny
- Region-Inserm Team NeoVasc ERI28, Laboratory of Microvascular Endothelium and Neonate Brain Lesions, Institute of Research for Innovation in Biomedicine, Normandy University, Rouen, France
| | - Céline Lesueur
- Region-Inserm Team NeoVasc ERI28, Laboratory of Microvascular Endothelium and Neonate Brain Lesions, Institute of Research for Innovation in Biomedicine, Normandy University, Rouen, France; Department of Medical Biochemistry, Rouen University Hospital, Rouen, France
| | - Virginie Girault
- Region-Inserm Team NeoVasc ERI28, Laboratory of Microvascular Endothelium and Neonate Brain Lesions, Institute of Research for Innovation in Biomedicine, Normandy University, Rouen, France
| | - Valery Brunel
- Region-Inserm Team NeoVasc ERI28, Laboratory of Microvascular Endothelium and Neonate Brain Lesions, Institute of Research for Innovation in Biomedicine, Normandy University, Rouen, France; Department of Medical Biochemistry, Rouen University Hospital, Rouen, France
| | - Yasmina Ramdani
- Region-Inserm Team NeoVasc ERI28, Laboratory of Microvascular Endothelium and Neonate Brain Lesions, Institute of Research for Innovation in Biomedicine, Normandy University, Rouen, France
| | - Damien Genty
- Department of Pathology, Rouen University Hospital, Rouen, France
| | - Azeddine Driouich
- Research Platform of Cell Imagery (PRIMACEN), France; Laboratory of Glycobiology and Plant Extracellular Matrix (GLYCOMEV) EA 4358, France
| | - Annie Laquerrière
- Region-Inserm Team NeoVasc ERI28, Laboratory of Microvascular Endothelium and Neonate Brain Lesions, Institute of Research for Innovation in Biomedicine, Normandy University, Rouen, France; Department of Pathology, Rouen University Hospital, Rouen, France
| | - Stéphane Marret
- Region-Inserm Team NeoVasc ERI28, Laboratory of Microvascular Endothelium and Neonate Brain Lesions, Institute of Research for Innovation in Biomedicine, Normandy University, Rouen, France; Department of Neonatal Paediatrics and Intensive Care, Rouen University Hospital, Rouen, France
| | - Carole Brasse-Lagnel
- Region-Inserm Team NeoVasc ERI28, Laboratory of Microvascular Endothelium and Neonate Brain Lesions, Institute of Research for Innovation in Biomedicine, Normandy University, Rouen, France; Department of Medical Biochemistry, Rouen University Hospital, Rouen, France
| | - Bruno J Gonzalez
- Region-Inserm Team NeoVasc ERI28, Laboratory of Microvascular Endothelium and Neonate Brain Lesions, Institute of Research for Innovation in Biomedicine, Normandy University, Rouen, France.
| | - Soumeya Bekri
- Region-Inserm Team NeoVasc ERI28, Laboratory of Microvascular Endothelium and Neonate Brain Lesions, Institute of Research for Innovation in Biomedicine, Normandy University, Rouen, France; Department of Medical Biochemistry, Rouen University Hospital, Rouen, France
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Carroll J, Page TKW, Chiang SC, Kalmar B, Bode D, Greensmith L, Mckinnon PJ, Thorpe JR, Hafezparast M, El-Khamisy SF. Expression of a pathogenic mutation of SOD1 sensitizes aprataxin-deficient cells and mice to oxidative stress and triggers hallmarks of premature ageing. Hum Mol Genet 2015; 24:828-40. [PMID: 25274775 PMCID: PMC4291253 DOI: 10.1093/hmg/ddu500] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2014] [Revised: 09/02/2014] [Accepted: 09/26/2014] [Indexed: 11/13/2022] Open
Abstract
Aprataxin (APTX) deficiency causes progressive cerebellar degeneration, ataxia and oculomotor apraxia in man. Cell free assays and crystal structure studies demonstrate a role for APTX in resolving 5'-adenylated nucleic acid breaks, however, APTX function in vertebrates remains unclear due to the lack of an appropriate model system. Here, we generated a murine model in which a pathogenic mutant of superoxide dismutase 1 (SOD1(G93A)) is expressed in an Aptx-/- mouse strain. We report a delayed population doubling and accelerated senescence in Aptx-/- primary mouse fibroblasts, which is not due to detectable telomere instability or cell cycle deregulation but is associated with a reduction in transcription recovery following oxidative stress. Expression of SOD1(G93A) uncovers a survival defect ex vivo in cultured cells and in vivo in tissues lacking Aptx. The surviving neurons feature numerous and deep nuclear envelope invaginations, a hallmark of cellular stress. Furthermore, they possess an elevated number of high-density nuclear regions and a concomitant increase in histone H3 K9 trimethylation, hallmarks of silenced chromatin. Finally, the accelerated cellular senescence was also observed at the organismal level as shown by down-regulation of insulin-like growth factor 1 (IGF-1), a hallmark of premature ageing. Together, this study demonstrates a protective role of Aptx in vivo and suggests that its loss results in progressive accumulation of DNA breaks in the nervous system, triggering hallmarks of premature ageing, systemically.
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Affiliation(s)
- Jean Carroll
- Genome Damage and Stability Center, University of Sussex, Brighton BN1 9RQ, UK
| | - Tristan K W Page
- School of Life Science, University of Sussex, Brighton BN1 9QG, UK
| | - Shih-Chieh Chiang
- Department of Molecular Biology and Biotechnology, Krebs Institute, University of Sheffield, Sheffield S10 2TN, UK
| | - Bernadett Kalmar
- Sobell Department of Motor Neuroscience and Movement Disorders, UCL Institute of Neurology, Queen Square, London WC1N 3BG, UK
| | - David Bode
- School of Life Science, University of Sussex, Brighton BN1 9QG, UK
| | - Linda Greensmith
- Sobell Department of Motor Neuroscience and Movement Disorders, UCL Institute of Neurology, Queen Square, London WC1N 3BG, UK
| | - Peter J Mckinnon
- Department of Genetics, St Jude Children's Research Hospital, Memphis, TN 38105-3678, USA and
| | - Julian R Thorpe
- School of Life Science, University of Sussex, Brighton BN1 9QG, UK
| | | | - Sherif F El-Khamisy
- Genome Damage and Stability Center, University of Sussex, Brighton BN1 9RQ, UK Department of Molecular Biology and Biotechnology, Krebs Institute, University of Sheffield, Sheffield S10 2TN, UK Center of Genomics, Helmy Institute for Medical Sciences, Zewail City of Science and Technology, Giza, Egypt
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Baranello RJ, Bharani KL, Padmaraju V, Chopra N, Lahiri DK, Greig NH, Pappolla MA, Sambamurti K. Amyloid-beta protein clearance and degradation (ABCD) pathways and their role in Alzheimer's disease. Curr Alzheimer Res 2015; 12:32-46. [PMID: 25523424 PMCID: PMC4820400 DOI: 10.2174/1567205012666141218140953] [Citation(s) in RCA: 210] [Impact Index Per Article: 23.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2014] [Revised: 11/16/2014] [Accepted: 12/05/2014] [Indexed: 11/22/2022]
Abstract
Amyloid-β proteins (Aβ) of 42 (Aβ42) and 40 aa (Aβ40) accumulate as senile plaques (SP) and cerebrovascular amyloid protein deposits that are defining diagnostic features of Alzheimer's disease (AD). A number of rare mutations linked to familial AD (FAD) on the Aβ precursor protein (APP), Presenilin-1 (PS1), Presenilin- 2 (PS2), Adamalysin10, and other genetic risk factors for sporadic AD such as the ε4 allele of Apolipoprotein E (ApoE-ε4) foster the accumulation of Aβ and also induce the entire spectrum of pathology associated with the disease. Aβ accumulation is therefore a key pathological event and a prime target for the prevention and treatment of AD. APP is sequentially processed by β-site APP cleaving enzyme (BACE1) and γ-secretase, a multisubunit PS1/PS2-containing integral membrane protease, to generate Aβ. Although Aβ accumulates in all forms of AD, the only pathways known to be affected in FAD increase Aβ production by APP gene duplication or via base substitutions on APP and γ-secretase subunits PS1 and PS2 that either specifically increase the yield of the longer Aβ42 or both Aβ40 and Aβ42. However, the vast majority of AD patients accumulate Aβ without these known mutations. This led to proposals that impairment of Aβ degradation or clearance may play a key role in AD pathogenesis. Several candidate enzymes, including Insulin-degrading enzyme (IDE), Neprilysin (NEP), Endothelin-converting enzyme (ECE), Angiotensin converting enzyme (ACE), Plasmin, and Matrix metalloproteinases (MMPs) have been identified and some have even been successfully evaluated in animal models. Several studies also have demonstrated the capacity of γ-secretase inhibitors to paradoxically increase the yield of Aβ and we have recently established that the mechanism is by skirting Aβ degradation. This review outlines major cellular pathways of Aβ degradation to provide a basis for future efforts to fully characterize the panel of pathways responsible for Aβ turnover.
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Affiliation(s)
| | | | | | | | | | | | | | - Kumar Sambamurti
- Department of Neurosciences, Medical University of South Carolina, 173 Ashley Avenue, BSB 403, Charleston, SC 29425, USA.
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Jakhria T, Hellewell AL, Porter MY, Jackson MP, Tipping KW, Xue WF, Radford SE, Hewitt EW. β2-microglobulin amyloid fibrils are nanoparticles that disrupt lysosomal membrane protein trafficking and inhibit protein degradation by lysosomes. J Biol Chem 2014; 289:35781-94. [PMID: 25378395 PMCID: PMC4276847 DOI: 10.1074/jbc.m114.586222] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
Fragmentation of amyloid fibrils produces fibrils that are reduced in length but have an otherwise unchanged molecular architecture. The resultant nanoscale fibril particles inhibit the cellular reduction of the tetrazolium dye 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT), a substrate commonly used to measure cell viability, to a greater extent than unfragmented fibrils. Here we show that the internalization of β2-microglobulin (β2m) amyloid fibrils is dependent on fibril length, with fragmented fibrils being more efficiently internalized by cells. Correspondingly, inhibiting the internalization of fragmented β2m fibrils rescued cellular MTT reduction. Incubation of cells with fragmented β2m fibrils did not, however, cause cell death. Instead, fragmented β2m fibrils accumulate in lysosomes, alter the trafficking of lysosomal membrane proteins, and inhibit the degradation of a model protein substrate by lysosomes. These findings suggest that nanoscale fibrils formed early during amyloid assembly reactions or by the fragmentation of longer fibrils could play a role in amyloid disease by disrupting protein degradation by lysosomes and trafficking in the endolysosomal pathway.
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Affiliation(s)
- Toral Jakhria
- From the School of Molecular and Cellular Biology and Astbury Centre for Structural Molecular Biology, University of Leeds, Leeds LS2 9JT, United Kingdom
| | - Andrew L Hellewell
- From the School of Molecular and Cellular Biology and Astbury Centre for Structural Molecular Biology, University of Leeds, Leeds LS2 9JT, United Kingdom
| | - Morwenna Y Porter
- From the School of Molecular and Cellular Biology and Astbury Centre for Structural Molecular Biology, University of Leeds, Leeds LS2 9JT, United Kingdom
| | - Matthew P Jackson
- From the School of Molecular and Cellular Biology and Astbury Centre for Structural Molecular Biology, University of Leeds, Leeds LS2 9JT, United Kingdom
| | - Kevin W Tipping
- From the School of Molecular and Cellular Biology and Astbury Centre for Structural Molecular Biology, University of Leeds, Leeds LS2 9JT, United Kingdom
| | - Wei-Feng Xue
- From the School of Molecular and Cellular Biology and Astbury Centre for Structural Molecular Biology, University of Leeds, Leeds LS2 9JT, United Kingdom
| | - Sheena E Radford
- From the School of Molecular and Cellular Biology and Astbury Centre for Structural Molecular Biology, University of Leeds, Leeds LS2 9JT, United Kingdom
| | - Eric W Hewitt
- From the School of Molecular and Cellular Biology and Astbury Centre for Structural Molecular Biology, University of Leeds, Leeds LS2 9JT, United Kingdom
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Couceiro JR, Gallardo R, De Smet F, De Baets G, Baatsen P, Annaert W, Roose K, Saelens X, Schymkowitz J, Rousseau F. Sequence-dependent internalization of aggregating peptides. J Biol Chem 2014; 290:242-58. [PMID: 25391649 DOI: 10.1074/jbc.m114.586636] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
Abstract
Recently, a number of aggregation disease polypeptides have been shown to spread from cell to cell, thereby displaying prionoid behavior. Studying aggregate internalization, however, is often hampered by the complex kinetics of the aggregation process, resulting in the concomitant uptake of aggregates of different sizes by competing mechanisms, which makes it difficult to isolate pathway-specific responses to aggregates. We designed synthetic aggregating peptides bearing different aggregation propensities with the aim of producing modes of uptake that are sufficiently distinct to differentially analyze the cellular response to internalization. We found that small acidic aggregates (≤500 nm in diameter) were taken up by nonspecific endocytosis as part of the fluid phase and traveled through the endosomal compartment to lysosomes. By contrast, bigger basic aggregates (>1 μm) were taken up through a mechanism dependent on cytoskeletal reorganization and membrane remodeling with the morphological hallmarks of phagocytosis. Importantly, the properties of these aggregates determined not only the mechanism of internalization but also the involvement of the proteostatic machinery (the assembly of interconnected networks that control the biogenesis, folding, trafficking, and degradation of proteins) in the process; whereas the internalization of small acidic aggregates is HSF1-independent, the uptake of larger basic aggregates was HSF1-dependent, requiring Hsp70. Our results show that the biophysical properties of aggregates determine both their mechanism of internalization and proteostatic response. It remains to be seen whether these differences in cellular response contribute to the particular role of specific aggregated proteins in disease.
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Affiliation(s)
- José R Couceiro
- From the Switch Laboratory, VIB, Leuven, Belgium, the Switch Laboratory, Department of Cellular and Molecular Medicine, KU Leuven, B-3000 Leuven, Belgium
| | - Rodrigo Gallardo
- From the Switch Laboratory, VIB, Leuven, Belgium, the Switch Laboratory, Department of Cellular and Molecular Medicine, KU Leuven, B-3000 Leuven, Belgium
| | - Frederik De Smet
- From the Switch Laboratory, VIB, Leuven, Belgium, the Switch Laboratory, Department of Cellular and Molecular Medicine, KU Leuven, B-3000 Leuven, Belgium
| | - Greet De Baets
- From the Switch Laboratory, VIB, Leuven, Belgium, the Switch Laboratory, Department of Cellular and Molecular Medicine, KU Leuven, B-3000 Leuven, Belgium
| | - Pieter Baatsen
- the Electron Microscopy Facility (EMoNe), KU Leuven Centre for Human Genetics, B-3000 Leuven, Belgium, the VIB BIO Imaging Core, VIB, B-3000 Leuven, Belgium
| | - Wim Annaert
- the Laboratory for Membrane Trafficking, KU Leuven and VIB-Centre for the Biology of Disease, B-3000 Leuven, Belgium
| | - Kenny Roose
- the VIB Inflammation Research Center, 9052 Ghent, Belgium, and the Department of Biomedical Molecular Biology, Ghent University, 9052 Ghent, Belgium
| | - Xavier Saelens
- the VIB Inflammation Research Center, 9052 Ghent, Belgium, and the Department of Biomedical Molecular Biology, Ghent University, 9052 Ghent, Belgium
| | - Joost Schymkowitz
- From the Switch Laboratory, VIB, Leuven, Belgium, the Switch Laboratory, Department of Cellular and Molecular Medicine, KU Leuven, B-3000 Leuven, Belgium
| | - Frederic Rousseau
- From the Switch Laboratory, VIB, Leuven, Belgium, the Switch Laboratory, Department of Cellular and Molecular Medicine, KU Leuven, B-3000 Leuven, Belgium,
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Roux C, Lesueur C, Aligny C, Brasse-Lagnel C, Genty D, Marret S, Laquerrière A, Bekri S, Gonzalez BJ. 3-MA Inhibits Autophagy and Favors Long-Term Integration of Grafted Gad67–GFP GABAergic Precursors in the Developing Neocortex by Preventing Apoptosis. Cell Transplant 2014; 23:1425-50. [DOI: 10.3727/096368913x670174] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
In human neonates, immature GABAergic interneurons are markedly affected by an excitotoxic insult. While in adults the interest of cell transplantation has been demonstrated in several neurological disorders, few data are available regarding the immature brain. The low survival rate constitutes a strong limitation in the capacity of transplanted neurons to integrate the host tissue. Because i) autophagy is an adaptive process to energetic/nutrient deprivation essential for cell survival and ii) literature describes cross-talks between autophagy and apoptosis, we hypothesized that regulation of autophagy would represent an original strategy to favor long-term survival of GABAergic precursors grafted in the immature neocortex. Morphological, neurochemical, and functional data showed that in control conditions, few grafted Gad67-GFP precursors survived. The first hours following transplantation were a critical period with intense apoptosis. Experiments performed on E15.5 ganglionic eminences revealed that Gad67-GFP precursors were highly sensitive to autophagy. Rapamycin and 3-MA impacted on LC3 cleavage, LC3II translocation, and autophagosome formation. Quantification of Bax, mitochondrial integrity, caspase-3 cleavage, and caspase-3 immunolocalization and activity showed that 3-MA induced a significant decrease of Gad67-GFP precursor apoptosis. In vivo, 3-MA induced, within the first 24 h, a diffuse LC3 pattern of grafted Gad67-GFP precursors, an increase of precursors with neurites, a reduction of the density of caspase-3 immunoreactive cells. A twofold increase in the survival rate occurred 15 days after the graft. Surviving neurons were localized in the cortical layers II–IV, which were still immature when the transplantation was done. Altogether, these data indicate that inhibition of autophagy represents an original strategy to allow GABAergic interneurons to overpass the first critical hours following transplantation and to increase their long-term survival in mice neonates.
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Affiliation(s)
- Christian Roux
- NeoVasc Laboratory, ERI28, Microvascular Endothelium and Neonate Brain Lesions, Institute of Research for Innovation in Biomedicine, Normandy University, Rouen, France
| | - Céline Lesueur
- NeoVasc Laboratory, ERI28, Microvascular Endothelium and Neonate Brain Lesions, Institute of Research for Innovation in Biomedicine, Normandy University, Rouen, France
- Department of Medical Biochemistry, Rouen University Hospital, Rouen, France
| | - Caroline Aligny
- NeoVasc Laboratory, ERI28, Microvascular Endothelium and Neonate Brain Lesions, Institute of Research for Innovation in Biomedicine, Normandy University, Rouen, France
| | - Carole Brasse-Lagnel
- NeoVasc Laboratory, ERI28, Microvascular Endothelium and Neonate Brain Lesions, Institute of Research for Innovation in Biomedicine, Normandy University, Rouen, France
- Department of Medical Biochemistry, Rouen University Hospital, Rouen, France
| | - Damien Genty
- Department of Pathology, Rouen University Hospital, Rouen, France
| | - Stéphane Marret
- NeoVasc Laboratory, ERI28, Microvascular Endothelium and Neonate Brain Lesions, Institute of Research for Innovation in Biomedicine, Normandy University, Rouen, France
- Department of Neonatal Paediatrics and Intensive Care, Rouen Hospital, Rouen, France
| | - Annie Laquerrière
- NeoVasc Laboratory, ERI28, Microvascular Endothelium and Neonate Brain Lesions, Institute of Research for Innovation in Biomedicine, Normandy University, Rouen, France
- Department of Pathology, Rouen University Hospital, Rouen, France
| | - Soumeya Bekri
- NeoVasc Laboratory, ERI28, Microvascular Endothelium and Neonate Brain Lesions, Institute of Research for Innovation in Biomedicine, Normandy University, Rouen, France
- Department of Medical Biochemistry, Rouen University Hospital, Rouen, France
| | - Bruno J. Gonzalez
- NeoVasc Laboratory, ERI28, Microvascular Endothelium and Neonate Brain Lesions, Institute of Research for Innovation in Biomedicine, Normandy University, Rouen, France
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Goodchild SC, Sheynis T, Thompson R, Tipping KW, Xue WF, Ranson NA, Beales PA, Hewitt EW, Radford SE. β2-Microglobulin amyloid fibril-induced membrane disruption is enhanced by endosomal lipids and acidic pH. PLoS One 2014; 9:e104492. [PMID: 25100247 PMCID: PMC4123989 DOI: 10.1371/journal.pone.0104492] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2014] [Accepted: 07/11/2014] [Indexed: 12/28/2022] Open
Abstract
Although the molecular mechanisms underlying the pathology of amyloidoses are not well understood, the interaction between amyloid proteins and cell membranes is thought to play a role in several amyloid diseases. Amyloid fibrils of β2-microglobulin (β2m), associated with dialysis-related amyloidosis (DRA), have been shown to cause disruption of anionic lipid bilayers in vitro. However, the effect of lipid composition and the chemical environment in which β2m-lipid interactions occur have not been investigated previously. Here we examine membrane damage resulting from the interaction of β2m monomers and fibrils with lipid bilayers. Using dye release, tryptophan fluorescence quenching and fluorescence confocal microscopy assays we investigate the effect of anionic lipid composition and pH on the susceptibility of liposomes to fibril-induced membrane damage. We show that β2m fibril-induced membrane disruption is modulated by anionic lipid composition and is enhanced by acidic pH. Most strikingly, the greatest degree of membrane disruption is observed for liposomes containing bis(monoacylglycero)phosphate (BMP) at acidic pH, conditions likely to reflect those encountered in the endocytic pathway. The results suggest that the interaction between β2m fibrils and membranes of endosomal origin may play a role in the molecular mechanism of β2m amyloid-associated osteoarticular tissue destruction in DRA.
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Affiliation(s)
- Sophia C. Goodchild
- Astbury Centre for Structural Molecular Biology and School of Molecular and Cellular Biology, University of Leeds, Leeds, United Kingdom
| | - Tania Sheynis
- Astbury Centre for Structural Molecular Biology and School of Molecular and Cellular Biology, University of Leeds, Leeds, United Kingdom
| | - Rebecca Thompson
- Astbury Centre for Structural Molecular Biology and School of Molecular and Cellular Biology, University of Leeds, Leeds, United Kingdom
| | - Kevin W. Tipping
- Astbury Centre for Structural Molecular Biology and School of Molecular and Cellular Biology, University of Leeds, Leeds, United Kingdom
| | - Wei-Feng Xue
- Astbury Centre for Structural Molecular Biology and School of Molecular and Cellular Biology, University of Leeds, Leeds, United Kingdom
| | - Neil A. Ranson
- Astbury Centre for Structural Molecular Biology and School of Molecular and Cellular Biology, University of Leeds, Leeds, United Kingdom
| | - Paul A. Beales
- Astbury Centre for Structural Molecular Biology and School of Chemistry, University of Leeds, Leeds, United Kingdom
| | - Eric W. Hewitt
- Astbury Centre for Structural Molecular Biology and School of Molecular and Cellular Biology, University of Leeds, Leeds, United Kingdom
| | - Sheena E. Radford
- Astbury Centre for Structural Molecular Biology and School of Molecular and Cellular Biology, University of Leeds, Leeds, United Kingdom
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Marshall KE, Marchante R, Xue WF, Serpell LC. The relationship between amyloid structure and cytotoxicity. Prion 2014; 8:28860. [PMID: 24819071 PMCID: PMC4189889 DOI: 10.4161/pri.28860] [Citation(s) in RCA: 46] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/03/2022] Open
Abstract
Self-assembly of proteins and peptides into amyloid structures has been the subject of intense and focused research due to their association with neurodegenerative, age-related human diseases and transmissible prion diseases in humans and mammals. Of the disease associated amyloid assemblies, a diverse array of species, ranging from small oligomeric assembly intermediates to fibrillar structures, have been shown to have toxic potential. Equally, a range of species formed by the same disease associated amyloid sequences have been found to be relatively benign under comparable monomer equivalent concentrations and conditions. In recent years, an increasing number of functional amyloid systems have also been found. These developments show that not all amyloid structures are generically toxic to cells. Given these observations, it is important to understand why amyloid structures may encode such varied toxic potential despite sharing a common core molecular architecture. Here, we discuss possible links between different aspects of amyloidogenic structures and assembly mechanisms with their varied functional effects. We propose testable hypotheses for the relationship between amyloid structure and its toxic potential in the context of recent reports on amyloid sequence, structure, and toxicity relationships.
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Affiliation(s)
- Karen E Marshall
- School of Life Sciences; University of Sussex; Falmer, East Sussex UK; School of Biological Sciences; University of Kent; Canterbury, Kent UK
| | - Ricardo Marchante
- School of Life Sciences; University of Sussex; Falmer, East Sussex UK; School of Biological Sciences; University of Kent; Canterbury, Kent UK
| | - Wei-Feng Xue
- School of Life Sciences; University of Sussex; Falmer, East Sussex UK; School of Biological Sciences; University of Kent; Canterbury, Kent UK
| | - Louise C Serpell
- School of Life Sciences; University of Sussex; Falmer, East Sussex UK; School of Biological Sciences; University of Kent; Canterbury, Kent UK
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45
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Apoptosis induced by islet amyloid polypeptide soluble oligomers is neutralized by diabetes-associated specific antibodies. Sci Rep 2014; 4:4267. [PMID: 24589570 PMCID: PMC3940978 DOI: 10.1038/srep04267] [Citation(s) in RCA: 70] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2013] [Accepted: 02/05/2014] [Indexed: 11/24/2022] Open
Abstract
Soluble oligomeric assemblies of amyloidal proteins appear to act as major pathological agents in several degenerative disorders. Isolation and characterization of these oligomers is a pivotal step towards determination of their pathological relevance. Here we describe the isolation of Type 2 diabetes-associated islet amyloid polypeptide soluble cytotoxic oligomers; these oligomers induced apoptosis in cultured pancreatic cells, permeated model lipid vesicles and interacted with cell membranes following complete internalization. Moreover, antibodies which specifically recognized these assemblies, but not monomers or amyloid fibrils, were exclusively identified in diabetic patients and were shown to neutralize the apoptotic effect induced by these oligomers. Our findings support the notion that human IAPP peptide can form highly toxic oligomers. The presence of antibodies identified in the serum of diabetic patients confirms the pathological relevance of the oligomers. In addition, the newly identified structural epitopes may also provide new mechanistic insights and a molecular target for future therapy.
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46
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Al-Hilaly YK, Williams TL, Stewart-Parker M, Ford L, Skaria E, Cole M, Bucher WG, Morris KL, Sada AA, Thorpe JR, Serpell LC. A central role for dityrosine crosslinking of Amyloid-β in Alzheimer's disease. Acta Neuropathol Commun 2013; 1:83. [PMID: 24351276 PMCID: PMC3880074 DOI: 10.1186/2051-5960-1-83] [Citation(s) in RCA: 140] [Impact Index Per Article: 12.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2013] [Accepted: 12/07/2013] [Indexed: 12/23/2022] Open
Abstract
BACKGROUND Alzheimer's disease (AD) is characterized by the deposition of insoluble amyloid plaques in the neuropil composed of highly stable, self-assembled Amyloid-beta (Aβ) fibrils. Copper has been implicated to play a role in Alzheimer's disease. Dimers of Aβ have been isolated from AD brain and have been shown to be neurotoxic. RESULTS We have investigated the formation of dityrosine cross-links in Aβ42 formed by covalent ortho-ortho coupling of two tyrosine residues under conditions of oxidative stress with elevated copper and shown that dityrosine can be formed in vitro in Aβ oligomers and fibrils and that these links further stabilize the fibrils. Dityrosine crosslinking was present in internalized Aβ in cell cultures treated with oligomeric Aβ42 using a specific antibody for dityrosine by immunogold labeling transmission electron microscopy. Results also revealed the prevalence of dityrosine crosslinks in amyloid plaques in brain tissue and in cerebrospinal fluid from AD patients. CONCLUSIONS Aβ dimers may be stabilized by dityrosine crosslinking. These results indicate that dityrosine cross-links may play an important role in the pathogenesis of Alzheimer's disease and can be generated by reactive oxygen species catalyzed by Cu2+ ions. The observation of increased Aβ and dityrosine in CSF from AD patients suggests that this could be used as a potential biomarker of oxidative stress in AD.
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Affiliation(s)
- Youssra K Al-Hilaly
- School of Life Sciences, University of Sussex, Falmer BN1 9QG, UK
- College of Sciences, Chemistry department, Al-Mustansiriyah University, Baghdad, Iraq
| | | | | | - Lenzie Ford
- School of Life Sciences, University of Sussex, Falmer BN1 9QG, UK
| | - Eldhose Skaria
- School of Life Sciences, University of Sussex, Falmer BN1 9QG, UK
| | - Michael Cole
- School of Life Sciences, University of Sussex, Falmer BN1 9QG, UK
| | | | - Kyle L Morris
- School of Life Sciences, University of Sussex, Falmer BN1 9QG, UK
- Current address: School of Life Sciences, Gibbet Hill Campus, University of Warwick, Coventry CV4 7AL, UK
| | - Alaa Abdul Sada
- School of Life Sciences, University of Sussex, Falmer BN1 9QG, UK
| | - Julian R Thorpe
- School of Life Sciences, University of Sussex, Falmer BN1 9QG, UK
| | - Louise C Serpell
- School of Life Sciences, University of Sussex, Falmer BN1 9QG, UK
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47
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Mihai C, Chrisler WB, Xie Y, Hu D, Szymanski CJ, Tolic A, Klein JA, Smith JN, Tarasevich BJ, Orr G. Intracellular accumulation dynamics and fate of zinc ions in alveolar epithelial cells exposed to airborne ZnO nanoparticles at the air-liquid interface. Nanotoxicology 2013; 9:9-22. [PMID: 24289294 DOI: 10.3109/17435390.2013.859319] [Citation(s) in RCA: 47] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
Airborne nanoparticles (NPs) that enter the respiratory tract are likely to reach the alveolar region. Accumulating observations support a role for zinc oxide (ZnO) NP dissolution in toxicity, but the majority of in-vitro studies were conducted in cells exposed to NPs in growth media, where large doses of dissolved ions are shed into the exposure solution. To determine the precise intracellular accumulation dynamics and fate of zinc ions (Zn(2+)) shed by airborne NPs in the cellular environment, we exposed alveolar epithelial cells to aerosolized NPs at the air-liquid interface (ALI). Using a fluorescent indicator for Zn(2+), together with organelle-specific fluorescent proteins, we quantified Zn(2+) in single cells and organelles over time. We found that at the ALI, intracellular Zn(2+) values peaked 3 h post exposure and decayed to normal values by 12 h, while in submerged cultures, intracellular Zn(2+) values continued to increase over time. The lowest toxic NP dose at the ALI generated peak intracellular Zn(2+) values that were nearly three-folds lower than the peak values generated by the lowest toxic dose of NPs in submerged cultures, and eight-folds lower than the peak values generated by the lowest toxic dose of ZnSO4 or Zn(2+). At the ALI, the majority of intracellular Zn(2+) was found in endosomes and lysosomes as early as 1 h post exposure. In contrast, the majority of intracellular Zn(2+) following exposures to ZnSO4 was found in other larger vesicles, with less than 10% in endosomes and lysosomes. Together, our observations indicate that low but critical levels of intracellular Zn(2+) have to be reached, concentrated specifically in endosomes and lysosomes, for toxicity to occur, and point to the focal dissolution of the NPs in the cellular environment and the accumulation of the ions specifically in endosomes and lysosomes as the processes underlying the potent toxicity of airborne ZnO NPs.
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48
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Neurotoxicity and memory deficits induced by soluble low-molecular-weight amyloid-β1-42 oligomers are revealed in vivo by using a novel animal model. J Neurosci 2012; 32:7852-61. [PMID: 22674261 DOI: 10.1523/jneurosci.5901-11.2012] [Citation(s) in RCA: 133] [Impact Index Per Article: 11.1] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
Neuronal and synaptic degeneration are the best pathological correlates for memory decline in Alzheimer's disease (AD). Although the accumulation of soluble low-molecular-weight amyloid-β (Aβ) oligomers has been suggested to trigger neurodegeneration in AD, animal models overexpressing or infused with Aβ lack neuronal loss at the onset of memory deficits. Using a novel in vivo approach, we found that repeated hippocampal injections of small soluble Aβ(1-42) oligomers in awake, freely moving mice were able to induce marked neuronal loss, tau hyperphosphorylation, and deficits in hippocampus-dependent memory. The neurotoxicity of small Aβ(1-42) species was observed in vivo as well as in vitro in association with increased caspase-3 activity and reduced levels of the NMDA receptor subunit NR2B. We found that the sequestering agent transthyretin is able to bind the toxic Aβ(1-42) species and attenuated the loss of neurons and memory deficits. Our novel mouse model provides evidence that small, soluble Aβ(1-42) oligomers are able to induce extensive neuronal loss in vivo and initiate a cascade of events that mimic the key neuropathological hallmarks of AD.
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49
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Marsh SE, Blurton-Jones M. Examining the mechanisms that link β-amyloid and α-synuclein pathologies. ALZHEIMERS RESEARCH & THERAPY 2012; 4:11. [PMID: 22546279 PMCID: PMC4054672 DOI: 10.1186/alzrt109] [Citation(s) in RCA: 81] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/03/2012] [Accepted: 04/24/2012] [Indexed: 12/23/2022]
Abstract
β-amyloid (Aβ) and α-synuclein (α-syn) are aggregation-prone proteins typically associated with two distinct neurodegenerative disorders: Alzheimer's disease (AD) and Parkinson's disease. Yet α-syn was first found in association with AD plaques several years before being linked to Parkinson's disease or Lewy body formation. Nowadays, a large subset of AD patients (~50%) is well recognized to co-exhibit significant α-syn Lewy body pathology. Unfortunately, these AD Lewy body variant patients suffer from additional symptoms and an accelerated disease course. Basic research has begun to show that Aβ and α-syn may act synergistically to promote the aggregation and accumulation of each other. While the exact mechanisms by which these proteins interact remain unclear, growing evidence suggests that Aβ may drive α-syn pathology by impairing protein clearance, activating inflammation, enhancing phosphorylation, or directly promoting aggregation. This review examines the interactions between Aβ and α-syn and proposes potential mechanistic links between Aβ accumulation and α-syn pathogenesis.
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Affiliation(s)
- Samuel E Marsh
- Department of Neurobiology & Behavior, University of California, Irvine, Irvine, CA 92697-4545, USA
| | - Mathew Blurton-Jones
- Department of Neurobiology & Behavior, University of California, Irvine, Irvine, CA 92697-4545, USA ; Sue and Bill Gross Stem Cell Research Center, University of California Irvine, Irvine, CA 92697, USA ; Institute for Memory Impairments and Neurological Disorders, University of California Irvine, Irvine, CA 92697, USA
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