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Conteduca D, Brunetti G, Barth I, Quinn SD, Ciminelli C, Krauss TF. Multiplexed Near-Field Optical Trapping Exploiting Anapole States. ACS Nano 2023; 17:16695-16702. [PMID: 37603833 PMCID: PMC10510711 DOI: 10.1021/acsnano.3c03100] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/05/2023] [Accepted: 08/15/2023] [Indexed: 08/23/2023]
Abstract
Optical tweezers have had a major impact on bioscience research by enabling the study of biological particles with high accuracy. The focus so far has been on trapping individual particles, ranging from the cellular to the molecular level. However, biology is intrinsically heterogeneous; therefore, access to variations within the same population and species is necessary for the rigorous understanding of a biological system. Optical tweezers have demonstrated the ability of trapping multiple targets in parallel; however, the multiplexing capability becomes a challenge when moving toward the nanoscale. Here, we experimentally demonstrate a resonant metasurface that is capable of trapping a high number of nanoparticles in parallel, thereby opening up the field to large-scale multiplexed optical trapping. The unit cell of the metasurface supports an anapole state that generates a strong field enhancement for low-power near-field trapping; importantly, the anapole state is also more angle-tolerant than comparable resonant modes, which allows its excitation with a focused light beam, necessary for generating the required power density and optical forces. We use the anapole state to demonstrate the trapping of 100's of 100 nm polystyrene beads over a 10 min period, as well as the multiplexed trapping of lipid vesicles with a moderate intensity of <250 μW/μm2. This demonstration will enable studies relating to the heterogeneity of biological systems, such as viruses, extracellular vesicles, and other bioparticles at the nanoscale.
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Affiliation(s)
- Donato Conteduca
- School
of Physics, Engineering and Technology, University of York, Heslington, York YO10 5DD, United Kingdom
| | | | - Isabel Barth
- School
of Physics, Engineering and Technology, University of York, Heslington, York YO10 5DD, United Kingdom
| | - Steven D. Quinn
- School
of Physics, Engineering and Technology, University of York, Heslington, York YO10 5DD, United Kingdom
- York
Biomedical Research Institute, University
of York, Heslington, York YO10 5DD, United
Kingdom
| | | | - Thomas F. Krauss
- School
of Physics, Engineering and Technology, University of York, Heslington, York YO10 5DD, United Kingdom
- York
Biomedical Research Institute, University
of York, Heslington, York YO10 5DD, United
Kingdom
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2
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Lecinski S, Shepherd JW, Bunting K, Dresser L, Quinn SD, MacDonald C, Leake MC. Correlating viscosity and molecular crowding with fluorescent nanobeads and molecular probes: in vitro and in vivo. Interface Focus 2022; 12:20220042. [PMID: 36330320 PMCID: PMC9560789 DOI: 10.1098/rsfs.2022.0042] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2022] [Accepted: 09/05/2022] [Indexed: 02/02/2023] Open
Abstract
In eukaryotes, intracellular physico-chemical properties like macromolecular crowding and cytoplasmic viscoelasticity influence key processes such as metabolic activities, molecular diffusion and protein folding. However, mapping crowding and viscoelasticity in living cells remains challenging. One approach uses passive rheology in which diffusion of exogenous fluorescent particles internalized in cells is tracked and physico-chemical properties inferred from derived mean square displacement relations. Recently, the crGE2.3 Förster resonance energy transfer biosensor was developed to quantify crowding in cells, though it is unclear how this readout depends on viscoelasticity and the molecular weight of the crowder. Here, we present correlative, multi-dimensional data to explore diffusion and molecular crowding characteristics of molecular crowding agents using super-resolved fluorescence microscopy and ensemble time-resolved spectroscopy. We firstly characterize in vitro and then apply these insights to live cells of budding yeast Saccharomyces cerevisiae. It is to our knowledge the first time this has been attempted. We demonstrate that these are usable both in vitro and in the case of endogenously expressed sensors in live cells. Finally, we present a method to internalize fluorescent beads as in situ viscoelasticity markers in the cytoplasm of live yeast cells and discuss limitations of this approach including impairment of cellular function.
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Affiliation(s)
- Sarah Lecinski
- Department of Physics, University of York, York YO10 5DD, UK
| | - Jack W. Shepherd
- Department of Physics, University of York, York YO10 5DD, UK
- Department of Biology, University of York, York YO10 5DD, UK
| | - Kate Bunting
- Department of Biology, University of York, York YO10 5DD, UK
| | - Lara Dresser
- Department of Physics, University of York, York YO10 5DD, UK
| | - Steven D. Quinn
- Department of Physics, University of York, York YO10 5DD, UK
| | - Chris MacDonald
- Department of Biology, University of York, York YO10 5DD, UK
| | - Mark C. Leake
- Department of Physics, University of York, York YO10 5DD, UK
- Department of Biology, University of York, York YO10 5DD, UK
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3
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Quinn SD, Dresser L, Graham S, Conteduca D, Shepherd J, Leake MC. Crowding-induced morphological changes in synthetic lipid vesicles determined using smFRET. Front Bioeng Biotechnol 2022; 10:958026. [PMID: 36394015 PMCID: PMC9650091 DOI: 10.3389/fbioe.2022.958026] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2022] [Accepted: 10/13/2022] [Indexed: 12/02/2022] Open
Abstract
Lipid vesicles are valuable mesoscale molecular confinement vessels for studying membrane mechanics and lipid–protein interactions, and they have found utility among bio-inspired technologies, including drug delivery vehicles. While vesicle morphology can be modified by changing the lipid composition and introducing fusion or pore-forming proteins and detergents, the influence of extramembrane crowding on vesicle morphology has remained under-explored owing to a lack of experimental tools capable of capturing morphological changes on the nanoscale. Here, we use biocompatible polymers to simulate molecular crowding in vitro, and through combinations of FRET spectroscopy, lifetime analysis, dynamic light scattering, and single-vesicle imaging, we characterize how crowding regulates vesicle morphology. We show that both freely diffusing and surface-tethered vesicles fluorescently tagged with the DiI and DiD FRET pair undergo compaction in response to modest concentrations of sorbitol, polyethylene glycol, and Ficoll. A striking observation is that sorbitol results in irreversible compaction, whereas the influence of high molecular weight PEG-based crowders was found to be reversible. Regulation of molecular crowding allows for precise control of the vesicle architecture in vitro, with vast implications for drug delivery and vesicle trafficking systems. Furthermore, our observations of vesicle compaction may also serve to act as a mechanosensitive readout of extramembrane crowding.
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Affiliation(s)
- Steven D. Quinn
- School of Physics, Engineering and Technology, University of York, York, United Kingdom
- York Biomedical Research Institute, University of York, York, United Kingdom
| | - Lara Dresser
- School of Physics, Engineering and Technology, University of York, York, United Kingdom
| | - Sarah Graham
- School of Physics, Engineering and Technology, University of York, York, United Kingdom
| | - Donato Conteduca
- School of Physics, Engineering and Technology, University of York, York, United Kingdom
| | - Jack Shepherd
- School of Physics, Engineering and Technology, University of York, York, United Kingdom
- Department of Biology, University of York, York, United Kingdom
| | - Mark C. Leake
- School of Physics, Engineering and Technology, University of York, York, United Kingdom
- York Biomedical Research Institute, University of York, York, United Kingdom
- Department of Biology, University of York, York, United Kingdom
- *Correspondence: Mark C. Leake,
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4
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Connor JP, Quinn SD, Schaefer C. Sticker-and-spacer model for amyloid beta condensation and fibrillation. Front Mol Neurosci 2022; 15:962526. [PMID: 36311031 PMCID: PMC9611774 DOI: 10.3389/fnmol.2022.962526] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2022] [Accepted: 09/14/2022] [Indexed: 11/17/2022] Open
Abstract
A major pathogenic hallmark of Alzheimer's disease is the presence of neurotoxic plaques composed of amyloid beta (Aβ) peptides in patients' brains. The pathway of plaque formation remains elusive, though some clues appear to lie in the dominant presence of Aβ1 − 42 in these plaques despite Aβ1−40 making up approximately 90% of the Aβ pool. We hypothesize that this asymmetry is driven by the hydrophobicity of the two extra amino acids that are incorporated in Aβ1−42. To investigate this hypothesis at the level of single molecules, we have developed a molecular “sticker-and-spacer lattice model” of unfolded Aβ. The model protein has a single sticker that may reversibly dimerise and elongate into semi-flexible linear chains. The growth is hampered by excluded-volume interactions that are encoded by the hydrophilic spacers but are rendered cooperative by the attractive interactions of hydrophobic spacers. For sufficiently strong hydrophobicity, the chains undergo liquid-liquid phase-separation (LLPS) into condensates that facilitate the nucleation of fibers. We find that a small fraction of Aβ1−40 in a mixture of Aβ1−40 and Aβ1−42 shifts the critical concentration for LLPS to lower values. This study provides theoretical support for the hypothesis that LLPS condensates act as a precursor for aggregation and provides an explanation for the Aβ1−42-enrichment of aggregates in terms of hydrophobic interactions.
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Affiliation(s)
- Jack P. Connor
- Department of Biology, University of York, York, United Kingdom
- School of Physics, Engineering and Technology, University of York, York, United Kingdom
- Astbury Centre for Structural Molecular Biology, School of Molecular and Cellular Biology, University of Leeds, Leeds, United Kingdom
- *Correspondence: Jack P. Connor
| | - Steven D. Quinn
- School of Physics, Engineering and Technology, University of York, York, United Kingdom
- York Biomedical Research Institute, University of York, York, United Kingdom
| | - Charley Schaefer
- School of Physics, Engineering and Technology, University of York, York, United Kingdom
- Charley Schaefer
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5
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Srinivasan S, Regmi R, Lin X, Dreyer CA, Chen X, Quinn SD, He W, Coleman MA, Carraway KL, Zhang B, Schlau-Cohen GS. Ligand-induced transmembrane conformational coupling in monomeric EGFR. Nat Commun 2022; 13:3709. [PMID: 35794108 PMCID: PMC9259572 DOI: 10.1038/s41467-022-31299-z] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [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: 09/15/2021] [Accepted: 06/13/2022] [Indexed: 01/26/2023] Open
Abstract
Single pass cell surface receptors regulate cellular processes by transmitting ligand-encoded signals across the plasma membrane via changes to their extracellular and intracellular conformations. This transmembrane signaling is generally initiated by ligand binding to the receptors in their monomeric form. While subsequent receptor-receptor interactions are established as key aspects of transmembrane signaling, the contribution of monomeric receptors has been challenging to isolate due to the complexity and ligand-dependence of these interactions. By combining membrane nanodiscs produced with cell-free expression, single-molecule Förster Resonance Energy Transfer measurements, and molecular dynamics simulations, we report that ligand binding induces intracellular conformational changes within monomeric, full-length epidermal growth factor receptor (EGFR). Our observations establish the existence of extracellular/intracellular conformational coupling within a single receptor molecule. We implicate a series of electrostatic interactions in the conformational coupling and find the coupling is inhibited by targeted therapeutics and mutations that also inhibit phosphorylation in cells. Collectively, these results introduce a facile mechanism to link the extracellular and intracellular regions through the single transmembrane helix of monomeric EGFR, and raise the possibility that intramolecular transmembrane conformational changes upon ligand binding are common to single-pass membrane proteins.
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Affiliation(s)
- Shwetha Srinivasan
- grid.116068.80000 0001 2341 2786Department of Chemistry, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, MA 02139 USA
| | - Raju Regmi
- grid.116068.80000 0001 2341 2786Department of Chemistry, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, MA 02139 USA ,grid.4444.00000 0001 2112 9282Present Address: Institut Curie, CNRS, Laboratoire Physico Chimie Curie, Paris, France
| | - Xingcheng Lin
- grid.116068.80000 0001 2341 2786Department of Chemistry, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, MA 02139 USA
| | - Courtney A. Dreyer
- grid.27860.3b0000 0004 1936 9684Biochemistry and Molecular Medicine, University of California Davis School of Medicine, Sacramento, CA 95817 USA
| | - Xuyan Chen
- grid.116068.80000 0001 2341 2786Department of Chemistry, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, MA 02139 USA
| | - Steven D. Quinn
- grid.116068.80000 0001 2341 2786Department of Chemistry, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, MA 02139 USA ,grid.5685.e0000 0004 1936 9668Present Address: Department of Physics, University of York, York, UK
| | - Wei He
- grid.250008.f0000 0001 2160 9702Lawrence Livermore National Laboratory, Livermore, CA 94550 USA
| | - Matthew A. Coleman
- grid.250008.f0000 0001 2160 9702Lawrence Livermore National Laboratory, Livermore, CA 94550 USA ,grid.27860.3b0000 0004 1936 9684Radiation Oncology, University of California Davis School of Medicine, Sacramento, CA 95817 USA
| | - Kermit L. Carraway
- grid.27860.3b0000 0004 1936 9684Biochemistry and Molecular Medicine, University of California Davis School of Medicine, Sacramento, CA 95817 USA
| | - Bin Zhang
- grid.116068.80000 0001 2341 2786Department of Chemistry, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, MA 02139 USA
| | - Gabriela S. Schlau-Cohen
- grid.116068.80000 0001 2341 2786Department of Chemistry, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, MA 02139 USA
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6
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Dresser L, Graham SP, Miller LM, Schaefer C, Conteduca D, Johnson S, Leake MC, Quinn SD. Tween-20 Induces the Structural Remodeling of Single Lipid Vesicles. J Phys Chem Lett 2022; 13:5341-5350. [PMID: 35678387 PMCID: PMC9208007 DOI: 10.1021/acs.jpclett.2c00704] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2022] [Accepted: 05/31/2022] [Indexed: 05/04/2023]
Abstract
The solubilization of lipid membranes by Tween-20 is crucial for a number of biotechnological applications, but the mechanistic details remain elusive. Evidence from ensemble assays supports a solubilization model that encompasses surfactant association with the membrane and the release of mixed micelles to solution, but whether this process also involves intermediate transitions between regimes is unanswered. In search of mechanistic origins, increasing focus is placed on identifying Tween-20 interactions with controllable membrane mimetics. Here, we employed ultrasensitive biosensing approaches, including single-vesicle spectroscopy based on fluorescence and energy transfer from membrane-encapsulated molecules, to interrogate interactions between Tween-20 and submicrometer-sized vesicles below the optical diffraction limit. We discovered that Tween-20, even at concentrations below the critical micellar concentration, triggers stepwise and phase-dependent structural remodeling events, including permeabilization and swelling, in both freely diffusing and surface-tethered vesicles, highlighting the substantial impact the surfactant has on vesicle conformation and stability prior to lysis.
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Affiliation(s)
- Lara Dresser
- Department
of Physics, University of York, York YO10 5DD, U.K.
| | - Sarah P. Graham
- Department
of Physics, University of York, York YO10 5DD, U.K.
| | - Lisa M. Miller
- Department
of Electronic Engineering, University of
York, York YO10 5DD, U.K.
| | | | | | - Steven Johnson
- Department
of Electronic Engineering, University of
York, York YO10 5DD, U.K.
- York
Biomedical Research Institute, University
of York, York YO10 5DD, U.K.
| | - Mark C. Leake
- Department
of Physics, University of York, York YO10 5DD, U.K.
- Department
of Biology, University of York, York YO10 5DD, U.K.
- York
Biomedical Research Institute, University
of York, York YO10 5DD, U.K.
| | - Steven D. Quinn
- Department
of Physics, University of York, York YO10 5DD, U.K.
- York
Biomedical Research Institute, University
of York, York YO10 5DD, U.K.
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7
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Amoah A, Chiu S, Quinn SD. Choice of primary and secondary outcomes in randomised controlled trials evaluating treatment for uterine fibroids: a systematic review. BJOG 2021; 129:345-355. [PMID: 34536313 DOI: 10.1111/1471-0528.16933] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 08/12/2021] [Indexed: 11/30/2022]
Abstract
BACKGROUND Core outcome sets aim to reduce research heterogeneity and standardise reporting, allowing meaningful comparisons between studies. OBJECTIVES To report on outcomes used in randomised controlled trials (RCTs) investigating uterine fibroid treatments, towards the development of a core outcome set for fibroid research. SELECTION STRATEGY Database search of MEDLINE, PubMed, EMBASE and CINAHL (inception to July 2021) for all English-language RCTs involving surgical or radiological fibroid treatments. DATA COLLECTION AND ANALYSIS A total of 1885 texts were screened for eligibility by two reviewers independently according to PRISMA methodology. JADAD and Management of Otitis Media with Effusion in Cleft Palate (MOMENT) scores were used to assess methodological and outcome reporting quality of studies, respectively. Outcomes were mapped to nine domains. Non-parametric tests for correlation and to compare group medians were undertaken. MAIN RESULTS There were 23 primary outcomes (23 outcome measures) and 173 secondary outcomes (95 outcome measures) reported in 60 RCTs (5699 participants). The domains with highest frequency of primary outcomes reported were bleeding and quality of life (QoL). The most frequent primary outcomes were postoperative pain, QoL and menstrual bleeding. No primary outcomes were mapped to fertility domains. Median MOMENT outcome score was 5 (interquartile range 3). There was correlation between MOMENT outcome score and JADAD scores (r = 0.491, P = 0.0001), publishing journal impact factor (r = 0.419, P = 0.008) and publication year (r = 0.332, P = 0.01). CONCLUSION There is substantial variation in the outcomes reported in fibroid RCTs. There is a need for a core outcome set for fibroid research, to allow improved understanding regarding the effects of different treatments.
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Affiliation(s)
- A Amoah
- Imperial College London, London, UK
| | - S Chiu
- Imperial College London, London, UK.,Northwick Park Hospital, London Northwest University Healthcare NHS Trust, Harrow, UK
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8
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Amoah A, Joseph N, Reap S, Quinn SD. Appraisal of national and international uterine fibroid management guidelines: a systematic review. BJOG 2021; 129:356-364. [PMID: 34532956 DOI: 10.1111/1471-0528.16928] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 07/21/2021] [Indexed: 12/19/2022]
Abstract
BACKGROUND Guidelines standardise high-quality evidence-based management strategies for clinicians. Uterine fibroids are a highly prevalent condition and may exert significant morbidity. OBJECTIVES To appraise national and international uterine fibroid guidelines using the validated AGREE-II instrument. SELECTION STRATEGY Database search of PubMed and EMBASE from inception to October 2020 for all published English-language uterine fibroid clinical practice guidelines. DATA COLLECTION AND ANALYSIS In all, 939 abstracts were screened for eligibility by two reviewers independently. Three reviewers used the AGREE-II instrument to assess guideline quality in six domains. Recommendations were mapped to allow a narrative synthesis regarding areas of consensus and disagreement. MAIN RESULTS Eight national guidelines (AAGL, SOGC 2014, ACOG, ACR, SOGC 2019, CNGOF, ASRM and SOGC 2015) and one international guideline (RANZOG) were appraised. The highest scoring guideline was RANZOG 2001(score 56.5%). None of the guidelines met the a priori criteria for being high-quality overall (score ≥66%). There were 166 recommendations across guidelines. There were several areas of disagreement and uncertainty. There were only three areas of consensus. Supporting evidence was not evident for many recommendations; 27.7% of recommendations were based on expert opinion only. CONCLUSIONS There is a need for high-quality guidelines on fibroids given their heterogeneity across individuals and the large range of treatment modalities available. There are also areas of controversy in the management of fibroids (e.g. Ulipristal acetate, power morcellation), which should also be addressed in any guidelines. Future guidelines should be methodologically robust to allow high-quality decision-making regarding fibroid treatments. TWEETABLE ABSTRACT Current national fibroid guidelines have deficiencies in quality when appraised using the validated AGREE instrument.
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Affiliation(s)
- A Amoah
- Imperial College London, London, UK
| | - N Joseph
- University of Liverpool, Liverpool, UK
| | - S Reap
- University of Leicester, Leicester, UK
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9
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Dienerowitz M, Howard JAL, Quinn SD, Dienerowitz F, Leake MC. Single-molecule FRET dynamics of molecular motors in an ABEL trap. Methods 2021; 193:96-106. [PMID: 33571667 DOI: 10.1016/j.ymeth.2021.01.012] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2020] [Revised: 01/22/2021] [Accepted: 01/29/2021] [Indexed: 02/07/2023] Open
Abstract
Single-molecule Förster resonance energy transfer (smFRET) of molecular motors provides transformative insights into their dynamics and conformational changes both at high temporal and spatial resolution simultaneously. However, a key challenge of such FRET investigations is to observe a molecule in action for long enough without restricting its natural function. The Anti-Brownian ELectrokinetic Trap (ABEL trap) sets out to combine smFRET with molecular confinement to enable observation times of up to several seconds while removing any requirement of tethered surface attachment of the molecule in question. In addition, the ABEL trap's inherent ability to selectively capture FRET active molecules accelerates the data acquisition process. In this work we exemplify the capabilities of the ABEL trap in performing extended timescale smFRET measurements on the molecular motor Rep, which is crucial for removing protein blocks ahead of the advancing DNA replication machinery and for restarting stalled DNA replication. We are able to monitor single Rep molecules up to 6 seconds with sub-millisecond time resolution capturing multiple conformational switching events during the observation time. Here we provide a step-by-step guide for the rational design, construction and implementation of the ABEL trap for smFRET detection of Rep in vitro. We include details of how to model the electric potential at the trap site and use Hidden Markov analysis of the smFRET trajectories.
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Affiliation(s)
- Maria Dienerowitz
- Single-Molecule Microscopy Group, Universitätsklinikum Jena, Nonnenplan 2 - 4, 07743 Jena, Germany.
| | - Jamieson A L Howard
- Department of Physics, University of York, Heslington, York YO10 5DD, UK; Department of Biology, University of York, Heslington, York YO10 5DD, UK
| | - Steven D Quinn
- Department of Physics, University of York, Heslington, York YO10 5DD, UK; York Biomedical Research Institute, University of York, Heslington, York YO10 5DD, UK
| | - Frank Dienerowitz
- Ernst-Abbe-Hochschule Jena, University of Applied Sciences, Carl-Zeiss-Promenade 2, 07745 Jena, Germany
| | - Mark C Leake
- Department of Physics, University of York, Heslington, York YO10 5DD, UK; Department of Biology, University of York, Heslington, York YO10 5DD, UK; York Biomedical Research Institute, University of York, Heslington, York YO10 5DD, UK
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10
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Juan-Colás J, Dresser L, Morris K, Lagadou H, Ward RH, Burns A, Tear S, Johnson S, Leake MC, Quinn SD. The Mechanism of Vesicle Solubilization by the Detergent Sodium Dodecyl Sulfate. Langmuir 2020; 36:11499-11507. [PMID: 32870686 DOI: 10.1021/acs.langmuir.0c01810] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/08/2023]
Abstract
Membrane solubilization by sodium dodecyl sulfate (SDS) is indispensable for many established biotechnological applications, including viral inactivation and protein extraction. Although the ensemble thermodynamics have been thoroughly explored, the underlying molecular dynamics have remained inaccessible, owing to major limitations of traditional measurement tools. Here, we integrate multiple advanced biophysical approaches to gain multiangle insight into the time-dependence and fundamental kinetic steps associated with the solubilization of single submicron sized vesicles in response to SDS. We find that the accumulation of SDS molecules on intact vesicles triggers biphasic solubilization kinetics comprising an initial vesicle expansion event followed by rapid lipid loss and micellization. Our findings support a general mechanism of detergent-induced membrane solubilization, and we expect that the framework of correlative biophysical technologies presented here will form a general platform for elucidating the complex kinetics of membrane perturbation induced by a wide variety of surfactants and disrupting agents.
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Affiliation(s)
- José Juan-Colás
- Department of Electronic Engineering, University of York, Heslington, York YO10 5DD, U.K
| | - Lara Dresser
- Department of Physics, University of York, Heslington, York YO10 5DD, U.K
| | - Katie Morris
- Department of Physics, University of York, Heslington, York YO10 5DD, U.K
| | - Hugo Lagadou
- Department of Physics, University of York, Heslington, York YO10 5DD, U.K
| | - Rebecca H Ward
- Department of Physics, University of York, Heslington, York YO10 5DD, U.K
| | - Amy Burns
- Department of Physics, University of York, Heslington, York YO10 5DD, U.K
| | - Steve Tear
- Department of Physics, University of York, Heslington, York YO10 5DD, U.K
| | - Steven Johnson
- Department of Electronic Engineering, University of York, Heslington, York YO10 5DD, U.K
- York Biomedical Research Institute, University of York, Heslington, York YO10 5DD, U.K
| | - Mark C Leake
- Department of Physics, University of York, Heslington, York YO10 5DD, U.K
- Department of Biology, University of York, Heslington, York YO10 5DD, U.K
- York Biomedical Research Institute, University of York, Heslington, York YO10 5DD, U.K
| | - Steven D Quinn
- Department of Physics, University of York, Heslington, York YO10 5DD, U.K
- York Biomedical Research Institute, University of York, Heslington, York YO10 5DD, U.K
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11
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Dresser L, Hunter P, Yendybayeva F, Hargreaves AL, Howard JAL, Evans GJO, Leake MC, Quinn SD. Amyloid-β oligomerization monitored by single-molecule stepwise photobleaching. Methods 2020; 193:80-95. [PMID: 32544592 PMCID: PMC8336786 DOI: 10.1016/j.ymeth.2020.06.007] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2020] [Revised: 06/02/2020] [Accepted: 06/10/2020] [Indexed: 01/19/2023] Open
Abstract
Method enables investigation of amyloid-β oligomer stoichiometry without requiring extrinsic fluorescent probes. Uses single-molecule stepwise photobleaching in vitro. Unveils heterogeneity within populations of oligomers. Assays oligomer-induced dysregulation of intracellular Ca2+ homeostasis in living cells.
A major hallmark of Alzheimer’s disease is the misfolding and aggregation of the amyloid- β peptide (Aβ). While early research pointed towards large fibrillar- and plaque-like aggregates as being the most toxic species, recent evidence now implicates small soluble Aβ oligomers as being orders of magnitude more harmful. Techniques capable of characterizing oligomer stoichiometry and assembly are thus critical for a deeper understanding of the earliest stages of neurodegeneration and for rationally testing next-generation oligomer inhibitors. While the fluorescence response of extrinsic fluorescent probes such as Thioflavin-T have become workhorse tools for characterizing large Aβ aggregates in solution, it is widely accepted that these methods suffer from many important drawbacks, including an insensitivity to oligomeric species. Here, we integrate several biophysics techniques to gain new insight into oligomer formation at the single-molecule level. We showcase single-molecule stepwise photobleaching of fluorescent dye molecules as a powerful method to bypass many of the traditional limitations, and provide a step-by-step guide to implementing the technique in vitro. By collecting fluorescence emission from single Aβ(1–42) peptides labelled at the N-terminal position with HiLyte Fluor 555 via wide-field total internal reflection fluorescence (TIRF) imaging, we demonstrate how to characterize the number of peptides per single immobile oligomer and reveal heterogeneity within sample populations. Importantly, fluorescence emerging from Aβ oligomers cannot be easily investigated using diffraction-limited optical microscopy tools. To assay oligomer activity, we also demonstrate the implementation of another biophysical method involving the ratiometric imaging of Fura-2-AM loaded cells which quantifies the rate of oligomer-induced dysregulation of intracellular Ca2+ homeostasis. We anticipate that the integrated single-molecule biophysics approaches highlighted here will develop further and in principle may be extended to the investigation of other protein aggregation systems under controlled experimental conditions.
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Affiliation(s)
- Lara Dresser
- Department of Physics, University of York, Heslington YO10 5DD, UK
| | - Patrick Hunter
- Department of Physics, University of York, Heslington YO10 5DD, UK
| | | | - Alex L Hargreaves
- Department of Physics, University of York, Heslington YO10 5DD, UK; Department of Biology, University of York, Heslington YO10 5DD, UK
| | - Jamieson A L Howard
- Department of Physics, University of York, Heslington YO10 5DD, UK; Department of Biology, University of York, Heslington YO10 5DD, UK
| | - Gareth J O Evans
- Department of Biology, University of York, Heslington YO10 5DD, UK; York Biomedical Research Institute, University of York, Heslington YO10 5DD, UK
| | - Mark C Leake
- Department of Physics, University of York, Heslington YO10 5DD, UK; Department of Biology, University of York, Heslington YO10 5DD, UK; York Biomedical Research Institute, University of York, Heslington YO10 5DD, UK
| | - Steven D Quinn
- Department of Physics, University of York, Heslington YO10 5DD, UK; York Biomedical Research Institute, University of York, Heslington YO10 5DD, UK.
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Dalgarno PA, Juan-Colás J, Hedley GJ, Piñeiro L, Novo M, Perez-Gonzalez C, Samuel IDW, Leake MC, Johnson S, Al-Soufi W, Penedo JC, Quinn SD. Unveiling the multi-step solubilization mechanism of sub-micron size vesicles by detergents. Sci Rep 2019; 9:12897. [PMID: 31501469 PMCID: PMC6733941 DOI: 10.1038/s41598-019-49210-0] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2019] [Accepted: 08/21/2019] [Indexed: 11/09/2022] Open
Abstract
The solubilization of membranes by detergents is critical for many technological applications and has become widely used in biochemistry research to induce cell rupture, extract cell constituents, and to purify, reconstitute and crystallize membrane proteins. The thermodynamic details of solubilization have been extensively investigated, but the kinetic aspects remain poorly understood. Here we used a combination of single-vesicle Förster resonance energy transfer (svFRET), fluorescence correlation spectroscopy and quartz-crystal microbalance with dissipation monitoring to access the real-time kinetics and elementary solubilization steps of sub-micron sized vesicles, which are inaccessible by conventional diffraction-limited optical methods. Real-time injection of a non-ionic detergent, Triton X, induced biphasic solubilization kinetics of surface-immobilized vesicles labelled with the Dil/DiD FRET pair. The nanoscale sensitivity accessible by svFRET allowed us to unambiguously assign each kinetic step to distortions of the vesicle structure comprising an initial fast vesicle-swelling event followed by slow lipid loss and micellization. We expect the svFRET platform to be applicable beyond the sub-micron sizes studied here and become a unique tool to unravel the complex kinetics of detergent-lipid interactions.
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Affiliation(s)
- Paul A Dalgarno
- SUPA School of Physics and Astronomy, University of St. Andrews, North Haugh, Fife, KY16 9SS, UK.,Institute of Biological Physics and Bioengineering, School of Engineering and Physical Sciences, Heriot-Watt University, Edinburgh, EH14 4AS, UK
| | - José Juan-Colás
- Department of Electronic Engineering, University of York, Heslington, York, YO10 5DD, UK
| | - Gordon J Hedley
- SUPA School of Physics and Astronomy, University of St. Andrews, North Haugh, Fife, KY16 9SS, UK.,School of Chemistry, University of Glasgow, Glasgow, Scotland, G12 8QQ, United Kingdom
| | - Lucas Piñeiro
- Department of Physical Chemistry, Faculty of Science, University of Santiago de Compostela, Lugo, E-27002, Spain
| | - Mercedes Novo
- Department of Physical Chemistry, Faculty of Science, University of Santiago de Compostela, Lugo, E-27002, Spain
| | - Cibran Perez-Gonzalez
- SUPA School of Physics and Astronomy, University of St. Andrews, North Haugh, Fife, KY16 9SS, UK
| | - Ifor D W Samuel
- SUPA School of Physics and Astronomy, University of St. Andrews, North Haugh, Fife, KY16 9SS, UK
| | - Mark C Leake
- Department of Physics, University of York, Heslington, York, England, YO10 5DD, UK.,Department of Biology, University of York, Heslington, York, YO10 5DD, UK
| | - Steven Johnson
- Department of Electronic Engineering, University of York, Heslington, York, YO10 5DD, UK
| | - Wajih Al-Soufi
- Department of Physical Chemistry, Faculty of Science, University of Santiago de Compostela, Lugo, E-27002, Spain
| | - J Carlos Penedo
- SUPA School of Physics and Astronomy, University of St. Andrews, North Haugh, Fife, KY16 9SS, UK. .,Biomedical Sciences Research Complex, University of St. Andrews, North Haugh, St. Andrews, Fife, KY16 9ST, UK.
| | - Steven D Quinn
- SUPA School of Physics and Astronomy, University of St. Andrews, North Haugh, Fife, KY16 9SS, UK. .,Department of Physics, University of York, Heslington, York, England, YO10 5DD, UK. .,Department of Biology, University of York, Heslington, York, YO10 5DD, UK.
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13
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Quinn SD, Srinivasan S, Gordon JB, He W, Carraway KL, Coleman MA, Schlau-Cohen GS. Single-Molecule Fluorescence Detection of the Epidermal Growth Factor Receptor in Membrane Discs. Biochemistry 2018; 58:286-294. [PMID: 29553754 DOI: 10.1021/acs.biochem.8b00089] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
The epidermal growth factor receptor (EGFR) is critical to normal cellular signaling pathways. Moreover, it has been implicated in a range of pathologies, including cancer. As a result, it is the primary target of many anticancer drugs. One limitation to the design and development of these drugs has been the lack of molecular-level information about the interactions and conformational dynamics of EGFR. To overcome this limitation, this work reports the construction and characterization of functional, fluorescently labeled, and full-length EGFR in model membrane nanolipoprotein particles (NLPs) for in vitro fluorescence studies. To demonstrate the utility of the system, we investigate ATP-EGFR interactions. We observe that ATP binds at the catalytic site providing a means to measure a range of distances between the catalytic site and the C-terminus via Förster resonance energy transfer (FRET). These ATP-based experiments suggest a range of conformations of the C-terminus that may be a function of the phosphorylation state for EGFR. This work is a proof-of-principle demonstration of single-molecule studies as a noncrystallographic assay for EGFR interactions in real-time and under near-physiological conditions. The diverse nature of EGFR interactions means that new tools at the molecular level have the potential to significantly enhance our understanding of receptor pathology and are of utmost importance for cancer-related drug discovery.
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Affiliation(s)
- Steven D Quinn
- Department of Chemistry , Massachusetts Institute of Technology , 77 Massachusetts Avenue , Cambridge , Massachusetts 02139 , United States
| | - Shwetha Srinivasan
- Department of Chemistry , Massachusetts Institute of Technology , 77 Massachusetts Avenue , Cambridge , Massachusetts 02139 , United States
| | - Jesse B Gordon
- Department of Chemistry , Massachusetts Institute of Technology , 77 Massachusetts Avenue , Cambridge , Massachusetts 02139 , United States
| | - Wei He
- Lawrence Livermore National Laboratory , Livermore , California , United States
| | - Kermit L Carraway
- Biochemistry and Molecular Medicine , University of California Davis School of Medicine , Sacramento , California , United States
| | - Matthew A Coleman
- Lawrence Livermore National Laboratory , Livermore , California , United States.,Radiation Oncology , University of California Davis School of Medicine , Sacramento , California , United States
| | - Gabriela S Schlau-Cohen
- Department of Chemistry , Massachusetts Institute of Technology , 77 Massachusetts Avenue , Cambridge , Massachusetts 02139 , United States
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14
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Quinn SD, Magennis SW. Optical detection of gadolinium(iii) ions via quantum dot aggregation. RSC Adv 2017; 7:24730-24735. [PMID: 29308186 PMCID: PMC5735353 DOI: 10.1039/c7ra03969g] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2017] [Accepted: 04/28/2017] [Indexed: 11/21/2022] Open
Abstract
A rapid, sensitive and selective optical readout of the presence of gadolinium(iii) ions would have a wide range of applications for clinical and environmental monitoring. We demonstrate that water-soluble CdTe quantum dots (QDs) are induced to aggregate by Gd3+ ions in aqueous solution. By using a combination of photoluminescence spectroscopy, dynamic light scattering and fluorescence correlation spectroscopy (FCS) to monitor quantum dot aggregation kinetics, we correlate the efficiency of the self-quenching process with the degree of aggregation across a broad range of conditions, including different sizes of QDs. We attribute the aggregation to metal binding to the QD's surface ligands and the quenching to intra-aggregate energy transfer between QDs. When the strategy was applied to additional trivalent ions, the aggregation rate varied according to the particular trivalent metal ion used, suggesting that the selectivity can be enhanced and controlled by appropriate design of the capping ligands and solution conditions.
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Affiliation(s)
- Steven D Quinn
- WestCHEM, School of Chemistry, University of Glasgow, University Avenue, Glasgow, G12 8QQ, UK.
| | - Steven W Magennis
- WestCHEM, School of Chemistry, University of Glasgow, University Avenue, Glasgow, G12 8QQ, UK.
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Dalton CE, Quinn SD, Rafferty A, Morten MJ, Gardiner JM, Magennis SW. Single-Molecule Fluorescence Detection of a Synthetic Heparan Sulfate Disaccharide. Chemphyschem 2016; 17:3442-3446. [PMID: 27538128 PMCID: PMC5111599 DOI: 10.1002/cphc.201600750] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [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: 07/08/2016] [Indexed: 11/11/2022]
Abstract
The first single-molecule fluorescence detection of a structurally-defined synthetic carbohydrate is reported: a heparan sulfate (HS) disaccharide fragment labeled with Alexa488. Single molecules have been measured whilst freely diffusing in solution and controlled encapsulation in surface-tethered lipid vesicles has allowed extended observations of carbohydrate molecules down to the single-molecule level. The diverse and dynamic nature of HS-protein interactions means that new tools to investigate pure HS fragments at the molecular level would significantly enhance our understanding of HS. This work is a proof-of-principle demonstration of the feasibility of single-molecule studies of synthetic carbohydrates which offers a new approach to the study of pure glycosaminoglycan (GAG) fragments.
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Affiliation(s)
- Charlotte E Dalton
- The School of Chemistry and Manchester Institute of Biotechnology, The University of Manchester, 131 Princess Street, Manchester, M1 7DN, UK
| | - Steven D Quinn
- WestCHEM, School of Chemistry, University of Glasgow, Joseph Black Building, University Avenue, Glasgow, G12 8QQ, UK
| | - Aidan Rafferty
- WestCHEM, School of Chemistry, University of Glasgow, Joseph Black Building, University Avenue, Glasgow, G12 8QQ, UK
| | - Michael J Morten
- WestCHEM, School of Chemistry, University of Glasgow, Joseph Black Building, University Avenue, Glasgow, G12 8QQ, UK
| | - John M Gardiner
- The School of Chemistry and Manchester Institute of Biotechnology, The University of Manchester, 131 Princess Street, Manchester, M1 7DN, UK
| | - Steven W Magennis
- WestCHEM, School of Chemistry, University of Glasgow, Joseph Black Building, University Avenue, Glasgow, G12 8QQ, UK
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16
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Aitken L, Quinn SD, Perez-Gonzalez C, Samuel IDW, Penedo JC, Gunn-Moore FJ. Morphology-Specific Inhibition of β-Amyloid Aggregates by 17β-Hydroxysteroid Dehydrogenase Type 10. Chembiochem 2016; 17:1029-37. [PMID: 26991863 DOI: 10.1002/cbic.201600081] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2016] [Indexed: 11/08/2022]
Abstract
A major hallmark of Alzheimer's disease (AD) is the formation of toxic aggregates of the β-amyloid peptide (Aβ). Given that Aβ peptides are known to localise within mitochondria and interact with 17β-HSD10, a mitochondrial protein expressed at high levels in AD brains, we investigated the inhibitory potential of 17β-HSD10 against Aβ aggregation under a range of physiological conditions. Fluorescence self-quenching (FSQ) of Aβ(1-42) labelled with HiLyte Fluor 555 was used to evaluate the inhibitory effect under conditions established to grow distinct Aβ morphologies. 17β-HSD10 preferentially inhibits the formation of globular and fibrillar-like structures but has no effect on the growth of amorphous plaque-like aggregates at endosomal pH 6. This work provides insights into the dependence of the Aβ-17β-HSD10 interaction with the morphology of Aβ aggregates and how this impacts enzymatic function.
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Affiliation(s)
- Laura Aitken
- School of Biology, University of St. Andrews, Medical and Biological Sciences Building, North Haugh, St. Andrews, Fife, KY16 9TF, UK
| | - Steven D Quinn
- Organic Semiconductor Centre, SUPA, School of Physics and Astronomy, University of St. Andrews, North Haugh, St. Andrews, Fife, KY16 9SS, UK.,SUPA, School of Physics and Astronomy, University of St. Andrews, North Haugh, St. Andrews, Fife, KY16 9SS, UK.,WestCHEM, School of Chemistry, Joseph Black Building, University of Glasgow, University Avenue, Glasgow, G12 8QQ, UK
| | - Cibran Perez-Gonzalez
- SUPA, School of Physics and Astronomy, University of St. Andrews, North Haugh, St. Andrews, Fife, KY16 9SS, UK.,Biomedical Sciences Research Complex, University of St. Andrews, Biomolecular Sciences Building, North Haugh, St. Andrews, Fife, KY16 9ST, UK
| | - Ifor D W Samuel
- Organic Semiconductor Centre, SUPA, School of Physics and Astronomy, University of St. Andrews, North Haugh, St. Andrews, Fife, KY16 9SS, UK
| | - J Carlos Penedo
- SUPA, School of Physics and Astronomy, University of St. Andrews, North Haugh, St. Andrews, Fife, KY16 9SS, UK. .,Biomedical Sciences Research Complex, University of St. Andrews, Biomolecular Sciences Building, North Haugh, St. Andrews, Fife, KY16 9ST, UK.
| | - Frank J Gunn-Moore
- School of Biology, University of St. Andrews, Medical and Biological Sciences Building, North Haugh, St. Andrews, Fife, KY16 9TF, UK.
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17
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Baltierra-Jasso LE, Morten MJ, Laflör L, Quinn SD, Magennis SW. DNA Hairpin Dynamics under Molecular Crowding Conditions. Biophys J 2016. [DOI: 10.1016/j.bpj.2015.11.3397] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022] Open
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18
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Quinn SD, Dalton CE, Jeanneret RA, Gardiner JM, Magennis SW. Single-Molecule Studies of Fluorescently-Labelled Polysaccharides. Biophys J 2016. [DOI: 10.1016/j.bpj.2015.11.3404] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
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Affiliation(s)
- Laura E. Baltierra-Jasso
- The School of Chemistry and The Photon
Science Institute, The University of Manchester, Oxford Road, Manchester, M13 9PL, U.K
| | - Michael J. Morten
- WestCHEM, School of Chemistry, University of Glasgow, Joseph Black Building, University Avenue, Glasgow, G12 8QQ, U.K
| | - Linda Laflör
- WestCHEM, School of Chemistry, University of Glasgow, Joseph Black Building, University Avenue, Glasgow, G12 8QQ, U.K
| | - Steven D. Quinn
- WestCHEM, School of Chemistry, University of Glasgow, Joseph Black Building, University Avenue, Glasgow, G12 8QQ, U.K
| | - Steven W. Magennis
- WestCHEM, School of Chemistry, University of Glasgow, Joseph Black Building, University Avenue, Glasgow, G12 8QQ, U.K
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20
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Cameron RT, Quinn SD, Cairns LS, MacLeod R, Samuel IDW, Smith BO, Carlos Penedo J, Baillie GS. The phosphorylation of Hsp20 enhances its association with amyloid-β to increase protection against neuronal cell death. Mol Cell Neurosci 2014; 61:46-55. [PMID: 24859569 PMCID: PMC4148482 DOI: 10.1016/j.mcn.2014.05.002] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [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: 11/14/2013] [Revised: 04/29/2014] [Accepted: 05/01/2014] [Indexed: 01/25/2023] Open
Abstract
Up-regulation of Hsp20 protein levels in response to amyloid fibril formation is considered a key protective response against the onset of Alzheimer's disease (AD). Indeed, the physical interaction between Hsp20 and Aβ is known to prevent Aβ oligomerisation and protects neuronal cells from Aβ mediated toxicity, however, details of the molecular mechanism and regulatory cell signalling events behind this process have remained elusive. Using both conventional MTT end-point assays and novel real time measurement of cell impedance, we show that Hsp20 protects human neuroblastoma SH-SY5Y cells from the neurotoxic effects of Aβ. In an attempt to provide a mechanism for the neuroprotection afforded by Hsp20, we used peptide array, co-immunoprecipitation analysis and NMR techniques to map the interaction between Hsp20 and Aβ and report a binding mode where Hsp20 binds adjacent to the oligomerisation domain of Aβ, preventing aggregation. The Hsp20/Aβ interaction is enhanced by Hsp20 phosphorylation, which serves to increase association with low molecular weight Aβ species and decrease the effective concentration of Hsp20 required to disrupt the formation of amyloid oligomers. Finally, using a novel fluorescent assay for the real time evaluation of morphology-specific Aβ aggregation, we show that phospho-dependency of this effect is more pronounced for fibrils than for globular Aβ forms and that 25mers corresponding to the Hsp20 N-terminal can be used as Aβ aggregate inhibitors. Our report is the first to provide a molecular model for the Hsp20/Aβ complex and the first to suggest that modulation of the cAMP/cGMP pathways could be a novel route to enhance Hsp20-mediated attenuation of Aβ fibril neurotoxicity.
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Affiliation(s)
- Ryan T Cameron
- Institute of Cardiovascular and Medical Science, College of Veterinary, Medical and life sciences, University of Glasgow, Glasgow G128QQ, UK
| | - Steven D Quinn
- SUPA School of Physics and Astronomy, University of St Andrews, North Haugh, Fife KY169SS, UK
| | - Lynn S Cairns
- Institute of Cardiovascular and Medical Science, College of Veterinary, Medical and life sciences, University of Glasgow, Glasgow G128QQ, UK
| | - Ruth MacLeod
- Institute of Cardiovascular and Medical Science, College of Veterinary, Medical and life sciences, University of Glasgow, Glasgow G128QQ, UK
| | - Ifor D W Samuel
- SUPA School of Physics and Astronomy, University of St Andrews, North Haugh, Fife KY169SS, UK
| | - Brian O Smith
- Institute of Cardiovascular and Medical Science, College of Veterinary, Medical and life sciences, University of Glasgow, Glasgow G128QQ, UK
| | - J Carlos Penedo
- SUPA School of Physics and Astronomy, University of St Andrews, North Haugh, Fife KY169SS, UK
| | - George S Baillie
- Institute of Cardiovascular and Medical Science, College of Veterinary, Medical and life sciences, University of Glasgow, Glasgow G128QQ, UK.
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Quinn SD, Dalgarno PA, Cameron RT, Hedley GJ, Hacker C, Lucocq JM, Baillie GS, Samuel IDW, Penedo JC. Real-time probing of β-amyloid self-assembly and inhibition using fluorescence self-quenching between neighbouring dyes. ACTA ACUST UNITED AC 2014; 10:34-44. [DOI: 10.1039/c3mb70272c] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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Quinn SD, Deas LA, Dalgarno PA, Hedley GJ, Samuel ID, Penedo C. Solubilisation of Lipid Membranes by Detergents: Probing the Three-State Model at the Single Vesicle Level. Biophys J 2013. [DOI: 10.1016/j.bpj.2012.11.979] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022] Open
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23
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Bishop SJ, Murphy JM, Hicks R, Quinn SD, Lewis PD, Grace MP, Jellinek MS. The youngest victims of child maltreatment: what happens to infants in a court sample? Child Maltreat 2001; 6:243-249. [PMID: 11471631 DOI: 10.1177/1077559501006003005] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
Current data show that infants represent an increasing proportion of cases of child maltreatment. To learn more about how infants fare in the current system and to provide baseline data against which to compare outcomes following recent legislative reforms, this study examined a subsample of infants in a sample of 200 care and protection cases brought before the Boston Juvenile Court in 1994. Child, parent, and case characteristics of infants 0 to 3 months of age (n = 46) were compared with characteristics of older children in the sample. All cases were followed prospectively for 4 years, and data were abstracted from court records. Results revealed that the infants were primarily children of substance abusers who had extensive prior histories of child protective service system involvement. Although the majority of the infants were eventually permanently removed from parental custody and adopted, many experienced time delays and multiple placements before achieving permanent homes.
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Affiliation(s)
- S J Bishop
- Yale University, Bush Center in Child Development and Social Policy, USA
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Quinn SD, De Boni U. Enhanced neuronal regeneration by retinoic acid of murine dorsal root ganglia and of fetal murine and human spinal cord in vitro. In Vitro Cell Dev Biol 1991; 27:55-62. [PMID: 2013554 DOI: 10.1007/bf02630895] [Citation(s) in RCA: 44] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
This study demonstrates that retinoic acid (RA), an active metabolite of vitamin A, can act to enhance regeneration of neurites, at physiologic concentrations, in vitro. Explanted fragments of mouse dorsal root ganglia (DRG) and mouse and human spinal cord (SC) were maintained, in vitro, for periods up to 11 d. Murine DRG neurons were exposed to RA concentrations ranging from 100 microM to 1 nM, whereas neurons within murine and human SC explants were exposed to 10 microM to 10 nM RA. Results show that RA significantly (P less than 0.001) increases mean neurite length but not neurite number. Specifically, murine DRG neurons showed increases in mean neurite length of 30.7% with individual explants showing increases of up to 133.5%. Murine and human SC showed mean enhancements of 43.4 and 58.1%, respectively, but did so at lower concentrations of RA. The results indicate that RA may play a potentially critical role in neuronal regeneration.
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Affiliation(s)
- S D Quinn
- Faculty of Medicine, Department of Physiology, University of Toronto, Ontario, Canada
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