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Weiffert T, Meisl G, Flagmeier P, De S, Dunning CJR, Frohm B, Zetterberg H, Blennow K, Portelius E, Klenerman D, Dobson CM, Knowles TPJ, Linse S. Increased Secondary Nucleation Underlies Accelerated Aggregation of the Four-Residue N-Terminally Truncated Aβ42 Species Aβ5-42. ACS Chem Neurosci 2019; 10:2374-2384. [PMID: 30793584 DOI: 10.1021/acschemneuro.8b00676] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022] Open
Abstract
Aggregation of the amyloid-β (Aβ) peptide into plaques is believed to play a crucial role in Alzheimer's disease. Amyloid plaques consist of fibrils of full length Aβ peptides as well as N-terminally truncated species. β-Site amyloid precursor protein-cleaving enzyme (BACE1) cleaves amyloid precursor protein in the first step in Aβ peptide production and is an attractive therapeutic target to limit Aβ generation. Inhibition of BACE1, however, induces a unique pattern of Aβ peptides with increased levels of N-terminally truncated Aβ peptides starting at position 5 (Aβ5-X), indicating that these peptides are generated through a BACE1-independent pathway. Here we elucidate the aggregation mechanism of Aβ5-42 and its influence on full-length Aβ42. We find that, compared to Aβ42, Aβ5-42 is more aggregation prone and displays enhanced nucleation rates. Aβ5-42 oligomers cause nonspecific membrane disruption to similar extent as Aβ42 but appear at earlier time points in the aggregation reaction. Noteworthy, this implies similar toxicity of Aβ42 and Aβ5-42 and the toxic species are generated faster by Aβ5-42. The increased rate of secondary nucleation on the surface of existing fibrils originates from a higher affinity of Aβ5-42 monomers for fibrils, as compared to Aβ42: an effect that may be related to the reduced net charge of Aβ5-42. Moreover, Aβ5-42 and Aβ42 peptides coaggregate into heteromolecular fibrils and either species can elongate existing Aβ42 or Aβ5-42 fibrils but Aβ42 fibrils are more catalytic than Aβ5-42 fibrils. Our findings highlight the importance of the N-terminus for surface-catalyzed nucleation and thus the production of toxic oligomers.
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Affiliation(s)
- Tanja Weiffert
- Department of Biochemistry and Structural Biology, Lund University, P O box 124, 221 00 Lund, Sweden
| | - Georg Meisl
- Centre for Misfolding Disease, Department of Chemistry, Cambridge University, Lensfield Road, Cambridge CB2 1EW, United Kingdom
- Department of Chemistry, Cambridge University, Lensfield Road, Cambridge CB2 1EW, United Kingdom
| | - Patrick Flagmeier
- Centre for Misfolding Disease, Department of Chemistry, Cambridge University, Lensfield Road, Cambridge CB2 1EW, United Kingdom
- Department of Chemistry, Cambridge University, Lensfield Road, Cambridge CB2 1EW, United Kingdom
| | - Suman De
- Department of Chemistry, Cambridge University, Lensfield Road, Cambridge CB2 1EW, United Kingdom
| | - Christopher J. R. Dunning
- Department of Biochemistry and Structural Biology, Lund University, P O box 124, 221 00 Lund, Sweden
| | - Birgitta Frohm
- Department of Biochemistry and Structural Biology, Lund University, P O box 124, 221 00 Lund, Sweden
| | - Henrik Zetterberg
- Institute of Neuroscience
and Physiology, Department of Psychiatry and Neurochemistry, the Sahlgrenska
Academy at the University of Gothenburg, 431 80 Mölndal, Sweden
- Clinical Neurochemistry Laboratory, Sahlgrenska University Hospital, 431 80 Mölndal, Sweden
- Department of Neurodegenerative Disease, UCL Institute of Neurology, Queen Square, WC1N 3BG London, United Kingdom
- UK Dementia Research Institute, WC1E 6BT London, United Kingdom
| | - Kaj Blennow
- Institute of Neuroscience
and Physiology, Department of Psychiatry and Neurochemistry, the Sahlgrenska
Academy at the University of Gothenburg, 431 80 Mölndal, Sweden
- Clinical Neurochemistry Laboratory, Sahlgrenska University Hospital, 431 80 Mölndal, Sweden
| | - Erik Portelius
- Institute of Neuroscience
and Physiology, Department of Psychiatry and Neurochemistry, the Sahlgrenska
Academy at the University of Gothenburg, 431 80 Mölndal, Sweden
- Clinical Neurochemistry Laboratory, Sahlgrenska University Hospital, 431 80 Mölndal, Sweden
| | - David Klenerman
- Department of Chemistry, Cambridge University, Lensfield Road, Cambridge CB2 1EW, United Kingdom
- UK Dementia Research Institute, University of Cambridge, Cambridge CB2 0XY, United Kingdom
| | - Christopher M. Dobson
- Centre for Misfolding Disease, Department of Chemistry, Cambridge University, Lensfield Road, Cambridge CB2 1EW, United Kingdom
- Department of Chemistry, Cambridge University, Lensfield Road, Cambridge CB2 1EW, United Kingdom
| | - Tuomas P. J. Knowles
- Centre for Misfolding Disease, Department of Chemistry, Cambridge University, Lensfield Road, Cambridge CB2 1EW, United Kingdom
- Department of Chemistry, Cambridge University, Lensfield Road, Cambridge CB2 1EW, United Kingdom
- Department of Physics, Cavendish Laboratory, University of Cambridge, Cambridge CB3 0HE, United Kingdom
| | - Sara Linse
- Department of Biochemistry and Structural Biology, Lund University, P O box 124, 221 00 Lund, Sweden
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Yang Y, Boza-Serrano A, Dunning CJR, Clausen BH, Lambertsen KL, Deierborg T. Inflammation leads to distinct populations of extracellular vesicles from microglia. J Neuroinflammation 2018; 15:168. [PMID: 29807527 PMCID: PMC5972400 DOI: 10.1186/s12974-018-1204-7] [Citation(s) in RCA: 110] [Impact Index Per Article: 18.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2018] [Accepted: 05/15/2018] [Indexed: 11/10/2022] Open
Abstract
Background Activated microglia play an essential role in inflammatory responses elicited in the central nervous system (CNS). Microglia-derived extracellular vesicles (EVs) are suggested to be involved in propagation of inflammatory signals and in the modulation of cell-to-cell communication. However, there is a lack of knowledge on the regulation of EVs and how this in turn facilitates the communication between cells in the brain. Here, we characterized microglial EVs under inflammatory conditions and investigated the effects of inflammation on the EV size, quantity, and protein content. Methods We have utilized western blot, nanoparticle tracking analysis (NTA), and mass spectrometry to characterize EVs and examine the alterations of secreted EVs from a microglial cell line (BV2) following lipopolysaccharide (LPS) and tumor necrosis factor (TNF) inhibitor (etanercept) treatments, or either alone. The inflammatory responses were measured with multiplex cytokine ELISA and western blot. We also subjected TNF knockout mice to experimental stroke (permanent middle cerebral artery occlusion) and validated the effect of TNF inhibition on EV release. Results Our analysis of EVs originating from activated BV2 microglia revealed a significant increase in the intravesicular levels of TNF and interleukin (IL)-6. We also observed that the number of EVs released was reduced both in vitro and in vivo when inflammation was inhibited via the TNF pathway. Finally, via mass spectrometry, we identified 49 unique proteins in EVs released from LPS-activated microglia compared to control EVs (58 proteins in EVs released from LPS-activated microglia and 37 from control EVs). According to Gene Ontology (GO) analysis, we found a large increase of proteins related to translation and transcription in EVs from LPS. Importantly, we showed a distinct profile of proteins found in EVs released from LPS treated cells compared to control. Conclusions We demonstrate altered EV production in BV2 microglial cells and altered cytokine levels and protein composition carried by EVs in response to LPS challenge. Our findings provide new insights into the potential roles of EVs that could be related to the pathogenesis in neuroinflammatory diseases. Electronic supplementary material The online version of this article (10.1186/s12974-018-1204-7) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Yiyi Yang
- Department of Experimental Medical Science, Experimental Neuroinflammation Laboratory, Lund University, Lund, Sweden.
| | - Antonio Boza-Serrano
- Department of Experimental Medical Science, Experimental Neuroinflammation Laboratory, Lund University, Lund, Sweden
| | | | - Bettina Hjelm Clausen
- Department of Neurobiology Research, Institute of Molecular Medicine, University of Southern Denmark, Odense, Denmark.,BRIGDE-Brain Research-Inter-Disciplinary Guided Excellence, Department of Clinical Research, University of Southern Denmark, Odense, Denmark
| | - Kate Lykke Lambertsen
- Department of Neurobiology Research, Institute of Molecular Medicine, University of Southern Denmark, Odense, Denmark.,BRIGDE-Brain Research-Inter-Disciplinary Guided Excellence, Department of Clinical Research, University of Southern Denmark, Odense, Denmark.,Department of Neurology, Odense University Hospital, Odense, Denmark
| | - Tomas Deierborg
- Department of Experimental Medical Science, Experimental Neuroinflammation Laboratory, Lund University, Lund, Sweden.
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Dunning CJR, Black HL, Andrews KL, Davenport EC, Conboy M, Chawla S, Dowle AA, Ashford D, Thomas JR, Evans GJO. Multisite tyrosine phosphorylation of the N-terminus of Mint1/X11α by Src kinase regulates the trafficking of amyloid precursor protein. J Neurochem 2016; 137:518-27. [PMID: 26865271 PMCID: PMC4982022 DOI: 10.1111/jnc.13571] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2015] [Revised: 01/21/2016] [Accepted: 02/03/2016] [Indexed: 12/18/2022]
Abstract
Mint/X11 is one of the four neuronal trafficking adaptors that interact with amyloid precursor protein (APP) and are linked with its cleavage to generate β‐amyloid peptide, a key player in the pathology of Alzheimer's disease. How APP switches between adaptors at different stages of the secretory pathway is poorly understood. Here, we show that tyrosine phosphorylation of Mint1 regulates the destination of APP. A canonical SH2‐binding motif (202YEEI) was identified in the N‐terminus of Mint1 that is phosphorylated on tyrosine by C‐Src and recruits the active kinase for sequential phosphorylation of further tyrosines (Y191 and Y187). A single Y202F mutation in the Mint1 N‐terminus inhibits C‐Src binding and tyrosine phosphorylation. Previous studies observed that co‐expression of wild‐type Mint1 and APP causes accumulation of APP in the trans‐Golgi. Unphosphorylatable Mint1 (Y202F) or pharmacological inhibition of Src reduced the accumulation of APP in the trans‐Golgi of heterologous cells. A similar result was observed in cultured rat hippocampal neurons where Mint1(Y202F) permitted the trafficking of APP to more distal neurites than the wild‐type protein. These data underline the importance of the tyrosine phosphorylation of Mint1 as a critical switch for determining the destination of APP.
The regulation of amyloid precursor protein (APP) trafficking is poorly understood. We have discovered that the APP adapter, Mint1, is phosphorylated by C‐Src kinase. Mint1 causes APP accumulation in the trans‐Golgi network, whereas inhibition of Src or mutation of Mint1‐Y202 permits APP recycling. The phosphorylation status of Mint1 could impact on the pathological trafficking of APP in Alzheimer's disease.
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Affiliation(s)
| | | | | | | | | | | | - Adam A Dowle
- Department of Biology, University of York, York, UK
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Keenan S, Lewis PA, Wetherill SJ, Dunning CJR, Evans GJO. The N2-Src neuronal splice variant of C-Src has altered SH3 domain ligand specificity and a higher constitutive activity than N1-Src. FEBS Lett 2015; 589:1995-2000. [PMID: 26026271 PMCID: PMC4509517 DOI: 10.1016/j.febslet.2015.05.033] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2014] [Revised: 03/18/2015] [Accepted: 05/19/2015] [Indexed: 10/25/2022]
Abstract
N2-Src is a poorly understood neuronal splice variant of the ubiquitous C-Src tyrosine kinase, containing a 17 amino acid insert in its Src homology 3 (SH3) domain. To characterise the properties of N2-Src we directly compared its SH3 domain specificity and kinase activity with C- and N1-Src in vitro. N2- and N1-Src had a similar low affinity for the phosphorylation of substrates containing canonical C-Src SH3 ligands and synaptophysin, an established neuronal substrate for C-Src. N2-Src also had a higher basal kinase activity than N1- and C-Src in vitro and in cells, which could be explained by weakened intramolecular interactions. Therefore, N2-Src is a highly active kinase that is likely to phosphorylate alternative substrates to C-Src in the brain.
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Affiliation(s)
- Sarah Keenan
- Department of Biology and Hull York Medical School, University of York, Wentworth Way, York YO10 5DD, UK
| | - Philip A Lewis
- Department of Biology and Hull York Medical School, University of York, Wentworth Way, York YO10 5DD, UK
| | - Sarah J Wetherill
- Department of Biology and Hull York Medical School, University of York, Wentworth Way, York YO10 5DD, UK
| | - Christopher J R Dunning
- Department of Biology and Hull York Medical School, University of York, Wentworth Way, York YO10 5DD, UK
| | - Gareth J O Evans
- Department of Biology and Hull York Medical School, University of York, Wentworth Way, York YO10 5DD, UK.
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Abstract
α-Synuclein is a key protein in Parkinson disease. Not only is it the major protein component of Lewy bodies, but it is implicated in several cellular processes that are disrupted in Parkinson disease. Misfolded α-synuclein has also been shown to spread from cell-to-cell and, in a prion-like fashion, trigger aggregation of α-synuclein in the recipient cell. In this mini-review we explore the evidence that misfolded α-synuclein underlies the spread of pathology in Parkinson disease and discuss why it should be considered a prion-like protein.
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Dunning CJR, McKenzie M, Sugiana C, Lazarou M, Silke J, Connelly A, Fletcher JM, Kirby DM, Thorburn DR, Ryan MT. Human CIA30 is involved in the early assembly of mitochondrial complex I and mutations in its gene cause disease. EMBO J 2007; 26:3227-37. [PMID: 17557076 PMCID: PMC1914096 DOI: 10.1038/sj.emboj.7601748] [Citation(s) in RCA: 149] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2007] [Accepted: 05/15/2007] [Indexed: 11/09/2022] Open
Abstract
In humans, complex I of the respiratory chain is composed of seven mitochondrial DNA (mtDNA)-encoded and 38 nuclear-encoded subunits that assemble together in a process that is poorly defined. To date, only two complex I assembly factors have been identified and how each functions is not clear. Here, we show that the human complex I assembly factor CIA30 (complex I intermediate associated protein) associates with newly translated mtDNA-encoded complex I subunits at early stages in their assembly before dissociating at a later stage. Using antibodies we identified a CIA30-deficient patient who presented with cardioencephalomyopathy and reduced levels and activity of complex I. Genetic analysis revealed the patient had mutations in both alleles of the NDUFAF1 gene that encodes CIA30. Complex I assembly in patient cells was defective at early stages with subunits being degraded. Complementing the deficiency in patient fibroblasts with normal CIA30 using a novel lentiviral system restored steady-state complex I levels. Our results indicate that CIA30 is a crucial component in the early assembly of complex I and mutations in its gene can cause mitochondrial disease.
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Affiliation(s)
- C J R Dunning
- Department of Biochemistry, La Trobe University, Melbourne, Australia
| | - M McKenzie
- Department of Biochemistry, La Trobe University, Melbourne, Australia
| | - C Sugiana
- Murdoch Childrens Research Institute and Genetic Health Services Victoria, Royal Children's Hospital and Department of Paediatrics, University of Melbourne, Melbourne, Australia
| | - M Lazarou
- Department of Biochemistry, La Trobe University, Melbourne, Australia
| | - J Silke
- Department of Biochemistry, La Trobe University, Melbourne, Australia
| | - A Connelly
- Department of Biochemistry, La Trobe University, Melbourne, Australia
| | - J M Fletcher
- Department of Genetic Medicine, Women's and Children's Hospital and University of Adelaide, Adelaide, Australia
| | - D M Kirby
- Murdoch Childrens Research Institute and Genetic Health Services Victoria, Royal Children's Hospital and Department of Paediatrics, University of Melbourne, Melbourne, Australia
| | - D R Thorburn
- Murdoch Childrens Research Institute and Genetic Health Services Victoria, Royal Children's Hospital and Department of Paediatrics, University of Melbourne, Melbourne, Australia
| | - M T Ryan
- Department of Biochemistry, La Trobe University, Melbourne, Australia
- Department of Biochemistry, La Trobe University, Plenty Road, Melbourne, Victoria 3086, Australia. Tel.: +61 3 9479 2156; Fax: +61 3 9479 2467; E-mail:
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