1
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Yang Q, Hosseini E, Yao P, Pütz S, Gelléri M, Bonn M, Parekh SH, Liu X. Self-Blinking Thioflavin T for Super-resolution Imaging. J Phys Chem Lett 2024:7591-7596. [PMID: 39028951 DOI: 10.1021/acs.jpclett.4c00195] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 07/21/2024]
Abstract
Thioflavin T (ThT) is a typical dye used to visualize the aggregation and formation of fibrillar structures, e.g., amyloid fibrils and peptide nanofibrils. ThT has been considered to produce stable fluorescence when interacting with aggregated proteins. For single-molecule localization microscopy (SMLM)-based optical super-resolution imaging, a photoswitching/blinking fluorescence property is required. Here we demonstrate that, in contrast to previous reports, ThT exhibits intrinsic stochastic blinking properties, without the need for blinking imaging buffer, in stable binding conditions. The blinking properties (photon number, blinking time, and on-off duty cycle) of ThT at the single-molecule level (for ultralow concentrations) were investigated under different conditions. As a proof of concept, we performed SMLM imaging of ThT-labeled α-synuclein fibrils measured in air and PBS buffer.
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Affiliation(s)
- Qiqi Yang
- Max Planck Institute for Polymer Research, Ackermannweg 10, 55128 Mainz, Germany
| | - Elnaz Hosseini
- Max Planck Institute for Polymer Research, Ackermannweg 10, 55128 Mainz, Germany
| | - Peigen Yao
- Max Planck Institute for Polymer Research, Ackermannweg 10, 55128 Mainz, Germany
| | - Sabine Pütz
- Max Planck Institute for Polymer Research, Ackermannweg 10, 55128 Mainz, Germany
| | - Márton Gelléri
- Institute of Molecular Biology gGmbH, Ackermannweg 4, 55128 Mainz, Germany
| | - Mischa Bonn
- Max Planck Institute for Polymer Research, Ackermannweg 10, 55128 Mainz, Germany
| | - Sapun H Parekh
- Max Planck Institute for Polymer Research, Ackermannweg 10, 55128 Mainz, Germany
- Department of Biomedical Engineering, University of Texas at Austin, Austin, Texas 78712, United States
| | - Xiaomin Liu
- Max Planck Institute for Polymer Research, Ackermannweg 10, 55128 Mainz, Germany
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2
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Sun B, Ding T, Zhou W, Porter TS, Lew MD. Single-Molecule Orientation Imaging Reveals the Nano-Architecture of Amyloid Fibrils Undergoing Growth and Decay. NANO LETTERS 2024. [PMID: 38828968 DOI: 10.1021/acs.nanolett.4c01263] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2024]
Abstract
Amyloid-beta (Aβ42) aggregates are characteristic Alzheimer's disease signatures, but probing how their nanoscale architectures influence their growth and decay remains challenging using current technologies. Here, we apply time-lapse single-molecule orientation-localization microscopy (SMOLM) to measure the orientations and rotational "wobble" of Nile blue (NB) molecules transiently binding to Aβ42 fibrils. We correlate fibril architectures measured by SMOLM with their growth and decay over the course of 5 to 20 min visualized by single-molecule localization microscopy (SMLM). We discover that stable Aβ42 fibrils tend to be well-ordered and signified by well-aligned NB orientations and small wobble. SMOLM also shows that increasing order and disorder are signatures of growing and decaying fibrils, respectively. We also observe SMLM-invisible fibril remodeling, including steady growth and decay patterns that conserve β-sheet organization. SMOLM reveals that increased fibril architectural heterogeneity is correlated with dynamic remodeling and that large-scale fibril remodeling tends to originate from strongly heterogeneous local regions.
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Affiliation(s)
- Brian Sun
- Preston M. Green Department of Electrical and Systems Engineering, Washington University in St. Louis, St. Louis, Missouri 63130, United States
| | - Tianben Ding
- Preston M. Green Department of Electrical and Systems Engineering, Washington University in St. Louis, St. Louis, Missouri 63130, United States
| | - Weiyan Zhou
- Preston M. Green Department of Electrical and Systems Engineering, Washington University in St. Louis, St. Louis, Missouri 63130, United States
| | - Tara S Porter
- Preston M. Green Department of Electrical and Systems Engineering, Washington University in St. Louis, St. Louis, Missouri 63130, United States
| | - Matthew D Lew
- Preston M. Green Department of Electrical and Systems Engineering, Washington University in St. Louis, St. Louis, Missouri 63130, United States
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3
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Samueli B, Kezerle Y, Dreiher J, Osipov V, Steckbeck R, Vaknine H, Baraban JH. Shining Light on Photobleaching: An Artifact That Causes Unnecessary Excitation Among Pathologists. Arch Pathol Lab Med 2024; 148:e63-e68. [PMID: 37800669 DOI: 10.5858/arpa.2022-0311-oa] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 08/02/2023] [Indexed: 10/07/2023]
Abstract
CONTEXT.— Photobleaching artifact occurs when fluorescence intensity decreases following light exposure. Slides stained with fluorescent techniques may be stored in the dark until primary diagnostics. Experimental evidence suggesting the rate of photobleaching and necessity of dark storage is lacking. OBJECTIVE.— To compare photobleaching rate on direct immunofluorescence and Thioflavin T slides stored in ambient room light conditions and exposed to excitatory wavelengths. DESIGN.— During 2 iterations of the experiment, 45 slides were prepared, 42 with immunofluorescent antibodies plus 3 with thioflavin, from skin and kidney biopsies. The experimental group was stored in room light conditions in comparison to the control in the dark, at room temperature. Further, 1 immunofluorescence slide and 1 thioflavin slide were exposed to excitatory fluorescent light for several hours. Significant photobleaching was defined as an integer decrease in score (scale, 0-3). RESULTS.— Exposure times ranged from 152 to 3034 hours. Nine of the 42 immunofluorescence slides (21%) photobleached after a minimum exposure of 152 hours to room light, with no significant difference between the experimental and control groups (all P values >.05). The immunofluorescence slide exposed to fluorescent light for 4 hours showed marked photobleaching in the exposed field but not elsewhere. No thioflavin slides showed clinically significant photobleaching under any conditions. CONCLUSIONS.— Clinically significant photobleaching of slides exposed to room light may occur after a few days, but not a few hours (unless exposed to excitatory fluorescent light). Conversely, thioflavin-stained slides did not photobleach when exposed to ambient room air and photobleached only negligibly when exposed to excitatory fluorescent light.
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Affiliation(s)
- Benzion Samueli
- From the Department of Pathology (Samueli, Kezerle, Osipov) and Hospital Administration (Dreiher), Soroka University Medical Center, Be'er Sheva, Israel; Medical School of International Health and Faculty of Health Sciences (Samueli, Kezerle, Dreiher, Steckbeck) and the Department of Chemistry (Baraban), Ben Gurion University of the Negev, Be'er Sheva, Israel; and Institute of Pathology, E. Wolfson Medical Center, Holon, Israel, and Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel (Vaknine)
| | - Yarden Kezerle
- From the Department of Pathology (Samueli, Kezerle, Osipov) and Hospital Administration (Dreiher), Soroka University Medical Center, Be'er Sheva, Israel; Medical School of International Health and Faculty of Health Sciences (Samueli, Kezerle, Dreiher, Steckbeck) and the Department of Chemistry (Baraban), Ben Gurion University of the Negev, Be'er Sheva, Israel; and Institute of Pathology, E. Wolfson Medical Center, Holon, Israel, and Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel (Vaknine)
| | - Jacob Dreiher
- From the Department of Pathology (Samueli, Kezerle, Osipov) and Hospital Administration (Dreiher), Soroka University Medical Center, Be'er Sheva, Israel; Medical School of International Health and Faculty of Health Sciences (Samueli, Kezerle, Dreiher, Steckbeck) and the Department of Chemistry (Baraban), Ben Gurion University of the Negev, Be'er Sheva, Israel; and Institute of Pathology, E. Wolfson Medical Center, Holon, Israel, and Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel (Vaknine)
| | - Vladislav Osipov
- From the Department of Pathology (Samueli, Kezerle, Osipov) and Hospital Administration (Dreiher), Soroka University Medical Center, Be'er Sheva, Israel; Medical School of International Health and Faculty of Health Sciences (Samueli, Kezerle, Dreiher, Steckbeck) and the Department of Chemistry (Baraban), Ben Gurion University of the Negev, Be'er Sheva, Israel; and Institute of Pathology, E. Wolfson Medical Center, Holon, Israel, and Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel (Vaknine)
| | - Rachel Steckbeck
- From the Department of Pathology (Samueli, Kezerle, Osipov) and Hospital Administration (Dreiher), Soroka University Medical Center, Be'er Sheva, Israel; Medical School of International Health and Faculty of Health Sciences (Samueli, Kezerle, Dreiher, Steckbeck) and the Department of Chemistry (Baraban), Ben Gurion University of the Negev, Be'er Sheva, Israel; and Institute of Pathology, E. Wolfson Medical Center, Holon, Israel, and Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel (Vaknine)
| | - Hananya Vaknine
- From the Department of Pathology (Samueli, Kezerle, Osipov) and Hospital Administration (Dreiher), Soroka University Medical Center, Be'er Sheva, Israel; Medical School of International Health and Faculty of Health Sciences (Samueli, Kezerle, Dreiher, Steckbeck) and the Department of Chemistry (Baraban), Ben Gurion University of the Negev, Be'er Sheva, Israel; and Institute of Pathology, E. Wolfson Medical Center, Holon, Israel, and Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel (Vaknine)
| | - Joshua H Baraban
- From the Department of Pathology (Samueli, Kezerle, Osipov) and Hospital Administration (Dreiher), Soroka University Medical Center, Be'er Sheva, Israel; Medical School of International Health and Faculty of Health Sciences (Samueli, Kezerle, Dreiher, Steckbeck) and the Department of Chemistry (Baraban), Ben Gurion University of the Negev, Be'er Sheva, Israel; and Institute of Pathology, E. Wolfson Medical Center, Holon, Israel, and Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel (Vaknine)
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4
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Sun B, Ding T, Zhou W, Porter TS, Lew MD. Single-Molecule Orientation Imaging Reveals the Nano-Architecture of Amyloid Fibrils Undergoing Growth and Decay. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.03.24.586510. [PMID: 38585908 PMCID: PMC10996564 DOI: 10.1101/2024.03.24.586510] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/09/2024]
Abstract
Amyloid-beta ( A β 42 ) aggregates are characteristic signatures of Alzheimer's disease, but probing how their nanoscale architectures influence their growth and decay remains challenging using current technologies. Here, we apply time-lapse single-molecule orientation-localization microscopy (SMOLM) to measure the orientations and rotational "wobble" of Nile blue (NB) molecules transiently binding to A β 42 fibrils. We quantify correlations between fibril architectures, measured by SMOLM, and their growth and decay visualized by single-molecule localization microscopy (SMLM). We discover that stable A β 42 fibrils tend to be well-ordered, signified by well-aligned NB orientations and small wobble. SMOLM also shows that increasing order and disorder are signatures of growing and decaying A β 42 fibrils, respectively. We also observe SMLM-invisible fibril remodeling, including steady growth and decay patterns that conserve β -sheet organization. SMOLM reveals that increased heterogeneity in fibril architectures is correlated with more dynamic remodeling and that large-scale fibril remodeling tends to originate from local regions that exhibit strong heterogeneity.
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Affiliation(s)
- Brian Sun
- Department of Electrical and Systems Engineering, Washington University in St. Louis, St. Louis, MO, 63130
| | - Tianben Ding
- Department of Electrical and Systems Engineering, Washington University in St. Louis, St. Louis, MO, 63130
| | - Weiyan Zhou
- Department of Electrical and Systems Engineering, Washington University in St. Louis, St. Louis, MO, 63130
| | - Tara S. Porter
- Department of Electrical and Systems Engineering, Washington University in St. Louis, St. Louis, MO, 63130
| | - Matthew D. Lew
- Department of Electrical and Systems Engineering, Washington University in St. Louis, St. Louis, MO, 63130
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5
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Zhou W, O’Neill CL, Ding T, Zhang O, Rudra JS, Lew MD. Resolving the Nanoscale Structure of β-Sheet Peptide Self-Assemblies Using Single-Molecule Orientation-Localization Microscopy. ACS NANO 2024; 18:8798-8810. [PMID: 38478911 PMCID: PMC11025465 DOI: 10.1021/acsnano.3c11771] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 03/26/2024]
Abstract
Synthetic peptides that self-assemble into cross-β fibrils are versatile building blocks for engineered biomaterials due to their modularity and biocompatibility, but their structural and morphological similarities to amyloid species have been a long-standing concern for their translation. Further, their polymorphs are difficult to characterize by using spectroscopic and imaging techniques that rely on ensemble averaging to achieve high resolution. Here, we utilize Nile red (NR), an amyloidophilic fluorogenic probe, and single-molecule orientation-localization microscopy (SMOLM) to characterize fibrils formed by the designed amphipathic enantiomers KFE8L and KFE8D and the pathological amyloid-beta peptide Aβ42. Importantly, NR SMOLM reveals the helical (bilayer) ribbon structure of both KFE8 and Aβ42 and quantifies the precise tilt of the fibrils' inner and outer backbones in relevant buffer conditions without the need for covalent labeling or sequence mutations. SMOLM also distinguishes polymorphic branched and curved morphologies of KFE8, whose backbones exhibit much more heterogeneity than those of typical straight fibrils. Thus, SMOLM is a powerful tool to interrogate the structural differences and polymorphism between engineered and pathological cross-β-rich fibrils.
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Affiliation(s)
- Weiyan Zhou
- Department of Electrical and Systems Engineering, McKelvey School of Engineering, Washington University in St. Louis, MO 63130, USA
| | - Conor L. O’Neill
- Department of Biomedical Engineering, McKelvey School of Engineering, Washington University in St. Louis, MO 63130, USA
| | - Tianben Ding
- Department of Electrical and Systems Engineering, McKelvey School of Engineering, Washington University in St. Louis, MO 63130, USA
| | - Oumeng Zhang
- Department of Electrical and Systems Engineering, McKelvey School of Engineering, Washington University in St. Louis, MO 63130, USA
| | - Jai S. Rudra
- Department of Biomedical Engineering, McKelvey School of Engineering, Washington University in St. Louis, MO 63130, USA
| | - Matthew D. Lew
- Department of Electrical and Systems Engineering, McKelvey School of Engineering, Washington University in St. Louis, MO 63130, USA
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6
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Mahato J, Mukherjee R, Bose A, Mehra S, Gadhe L, Maji SK, Chowdhury A. Sensitized Emission Imaging Allows Nanoscale Surface Polarity Mapping of α-Synuclein Amyloid Fibrils. ACS Chem Neurosci 2024; 15:108-118. [PMID: 38099928 DOI: 10.1021/acschemneuro.3c00467] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2024] Open
Abstract
When misfolded, α-Synuclein (α-Syn), a natively disordered protein, aggregates to form amyloid fibrils responsible for the neurodegeneration observed in Parkinson's disease. Structural studies revealed distinct molecular packing of α-Syn in different fibril polymorphs and variations of interprotofilament connections in the fibrillar architecture. Fibril polymorphs have been hypothesized to exhibit diverse surface polarities depending on the folding state of the protein during aggregation; however, the spatial variation of surface polarity in amyloid fibrils remains unexplored. To map the local polarity (or hydrophobicity) along α-Syn fibrils, we visualized the spectral characteristics of two dyes with distinct polarities-hydrophilic Thioflavin T (ThT) and hydrophobic Nile red (NR)─when both are bound to α-Syn fibrils. Dual-channel fluorescence imaging reveals uneven partitioning of ThT and NR along individual fibrils, implying that relatively more polar/hydrophobic patches are spread over a few hundred nanometers. Remarkably, spectrally resolved sensitized emission imaging of α-Syn fibrils provides unambiguous evidence of energy transfer from ThT to NR, implying that dyes of dissimilar polarity are in close proximity. Furthermore, spatially resolved fluorescence spectroscopy of the solvatochromic probe NR allowed us to quantitatively map the range and variation of the polarity parameter ET30 along individual fibrils. Our results suggest the existence of interlaced polar and nonpolar nanoscale domains throughout the fibrils; however, the relative populations of these patches vary considerably over larger length scales likely due to heterogeneous packing of α-Syn during fibrilization and dissimilar exposed polarities of polymorphic segments. The employed method may provide a foundation for imaging modalities of other similar structurally unresolved systems with diverse hydrophobic-hydrophilic topology.
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Affiliation(s)
- Jaladhar Mahato
- Department of Chemistry, Indian Institute of Technology Bombay, Powai 400076, Mumbai, India
| | - Rajat Mukherjee
- Department of Chemistry, Indian Institute of Technology Bombay, Powai 400076, Mumbai, India
| | - Abhik Bose
- Department of Chemistry, Indian Institute of Technology Bombay, Powai 400076, Mumbai, India
| | - Surabhi Mehra
- Department of Biosciences and Bioengineering, Indian Institute of Technology Bombay, Powai 400076, Mumbai, India
| | - Laxmikant Gadhe
- Department of Biosciences and Bioengineering, Indian Institute of Technology Bombay, Powai 400076, Mumbai, India
| | - Samir K Maji
- Department of Biosciences and Bioengineering, Indian Institute of Technology Bombay, Powai 400076, Mumbai, India
- Sunita Sanghi Centre of Ageing and Neurodegenerative Diseases, Indian Institute of Technology Bombay, Powai 400076, Mumbai, India
| | - Arindam Chowdhury
- Department of Chemistry, Indian Institute of Technology Bombay, Powai 400076, Mumbai, India
- Sunita Sanghi Centre of Ageing and Neurodegenerative Diseases, Indian Institute of Technology Bombay, Powai 400076, Mumbai, India
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7
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Wu T, King MR, Farag M, Pappu RV, Lew MD. Single fluorogen imaging reveals distinct environmental and structural features of biomolecular condensates. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.01.26.525727. [PMID: 36747818 PMCID: PMC9900924 DOI: 10.1101/2023.01.26.525727] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Abstract
Recent computations suggest that biomolecular condensates that form via macromolecular phase separation are network fluids featuring spatially inhomogeneous organization of the underlying molecules. Computations also point to unique conformations of molecules at condensate interfaces. Here, we test these predictions using high-resolution structural characterizations of condensates formed by intrinsically disordered prion-like low complexity domains (PLCDs). We leveraged the localization and orientational preferences of freely diffusing fluorogens and the solvatochromic effect whereby specific fluorogens are turned on in response to the physic-chemical properties of condensate microenvironments to facilitate single-molecule tracking and super-resolution imaging. We deployed three different fluorogens to probe internal microenvironments and molecular organization of PLCD condensates. The spatiotemporal resolution and environmental sensitivity afforded by single-fluorogen imaging shows that the internal environments of condensates are more hydrophobic than coexisting dilute phases. Molecules within condensates are organized in a spatially inhomogeneous manner featuring slow-moving nanoscale molecular clusters or hubs that coexist with fast-moving molecules. Finally, molecules at interfaces of condensates are found to have distinct orientational preferences when compared to the interiors. Our findings, which affirm computational predictions, help provide a structural basis for condensate viscoelasticity and dispel the notion of protein condensates being isotropic liquids defined by uniform internal densities.
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Affiliation(s)
- Tingting Wu
- Department of Electrical and Systems Engineering, Washington University in St. Louis, James F. McKelvey School of Engineering, Washington University in St. Louis; St. Louis, MO 63130, USA
- Center for Biomolecular Condensates, James F. McKelvey School of Engineering, Washington University in St. Louis; St. Louis, MO 63130, USA
| | - Matthew R King
- Center for Biomolecular Condensates, James F. McKelvey School of Engineering, Washington University in St. Louis; St. Louis, MO 63130, USA
- Department of Biomedical Engineering, Washington University in St. Louis, James F. McKelvey School of Engineering, Washington University in St. Louis; St. Louis, MO 63130, USA
| | - Mina Farag
- Center for Biomolecular Condensates, James F. McKelvey School of Engineering, Washington University in St. Louis; St. Louis, MO 63130, USA
- Department of Biomedical Engineering, Washington University in St. Louis, James F. McKelvey School of Engineering, Washington University in St. Louis; St. Louis, MO 63130, USA
| | - Rohit V Pappu
- Center for Biomolecular Condensates, James F. McKelvey School of Engineering, Washington University in St. Louis; St. Louis, MO 63130, USA
- Department of Biomedical Engineering, Washington University in St. Louis, James F. McKelvey School of Engineering, Washington University in St. Louis; St. Louis, MO 63130, USA
| | - Matthew D Lew
- Department of Electrical and Systems Engineering, Washington University in St. Louis, James F. McKelvey School of Engineering, Washington University in St. Louis; St. Louis, MO 63130, USA
- Center for Biomolecular Condensates, James F. McKelvey School of Engineering, Washington University in St. Louis; St. Louis, MO 63130, USA
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8
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Zhou W, O’Neill CL, Ding T, Zhang O, Rudra JS, Lew MD. Resolving the nanoscale structure of β-sheet assemblies using single-molecule orientation-localization microscopy. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.09.13.557571. [PMID: 37745382 PMCID: PMC10515885 DOI: 10.1101/2023.09.13.557571] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 09/26/2023]
Abstract
Synthetic peptides that self-assemble into cross-β fibrils have remarkable utility as engineered biomaterials due to their modularity and biocompatibility, but their structural and morphological similarity to amyloid species has been a long-standing concern for their translation. Further, their polymorphs are difficult to characterize using spectroscopic and imaging techniques that rely on ensemble averaging to achieve high resolution. Here, we utilize single-molecule orientation-localization microscopy (SMOLM) to characterize fibrils formed by the designed amphipathic enantiomers, KFE8L and KFE8D, and the pathological amyloid-beta peptide Aβ42. SMOLM reveals that the orientations of Nile red, as it transiently binds to both KFE8 and Aβ42, are consistent with a helical (bilayer) ribbon structure and convey the precise tilt of the fibrils' inner and outer backbones. SMOLM also finds polymorphic branched and curved morphologies of KFE8 whose backbones exhibit much more heterogeneity than those of more typical straight fibrils. Thus, SMOLM is a powerful tool to interrogate the structural differences and polymorphism between engineered and pathological cross β-rich fibrils.
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Affiliation(s)
- Weiyan Zhou
- Department of Electrical and Systems Engineering, McKelvey School of Engineering, Washington University in St. Louis, MO 63130, USA
| | - Conor L. O’Neill
- Department of Biomedical Engineering, McKelvey School of Engineering, Washington University in St. Louis, MO 63130, USA
| | - Tianben Ding
- Department of Electrical and Systems Engineering, McKelvey School of Engineering, Washington University in St. Louis, MO 63130, USA
| | - Oumeng Zhang
- Department of Electrical and Systems Engineering, McKelvey School of Engineering, Washington University in St. Louis, MO 63130, USA
| | - Jai S. Rudra
- Department of Biomedical Engineering, McKelvey School of Engineering, Washington University in St. Louis, MO 63130, USA
| | - Matthew D. Lew
- Department of Electrical and Systems Engineering, McKelvey School of Engineering, Washington University in St. Louis, MO 63130, USA
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9
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Tholen MME, Tas RP, Wang Y, Albertazzi L. Beyond DNA: new probes for PAINT super-resolution microscopy. Chem Commun (Camb) 2023; 59:8332-8342. [PMID: 37306078 PMCID: PMC10318573 DOI: 10.1039/d3cc00757j] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2023] [Accepted: 05/26/2023] [Indexed: 06/13/2023]
Abstract
In the last decade, point accumulation for imaging in nanoscale topography (PAINT) has emerged as a versatile tool for single-molecule localization microscopy (SMLM). Currently, DNA-PAINT is the most widely used, in which a transient stochastically binding DNA docking-imaging pair is used to reconstruct specific characteristics of biological or synthetic materials on a single-molecule level. Slowly, the need for PAINT probes that are not dependent on DNA has emerged. These probes can be based on (i) endogenous interactions, (ii) engineered binders, (iii) fusion proteins, or (iv) synthetic molecules and provide complementary applications for SMLM. Therefore, researchers have been expanding the PAINT toolbox with new probes. In this review, we provide an overview of the currently existing probes that go beyond DNA and their applications and challenges.
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Affiliation(s)
- Marrit M E Tholen
- Department of Biomedical Engineering, Institute of Complex Molecular Systems, Eindhoven University of Technology, Eindhoven, The Netherlands.
| | - Roderick P Tas
- Department of Chemical Engineering and Chemistry, Laboratory of Self-Organizing Soft Matter, Eindhoven University of Technology, Eindhoven, 5612 AP, The Netherlands
- Institute for Complex Molecular Systems, Eindhoven University of Technology, P.O. Box 513, 5600 MB Eindhoven, The Netherlands
| | - Yuyang Wang
- Institute for Complex Molecular Systems, Eindhoven University of Technology, P.O. Box 513, 5600 MB Eindhoven, The Netherlands
- Department of Applied Physics, Eindhoven University of Technology, P.O. Box 513, 5600 MB Eindhoven, The Netherlands
| | - Lorenzo Albertazzi
- Department of Biomedical Engineering, Institute of Complex Molecular Systems, Eindhoven University of Technology, Eindhoven, The Netherlands.
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10
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Sarkar A, Namboodiri V, Kumbhakar M. Single-Molecule Orientation Imaging Reveals Two Distinct Binding Configurations on Amyloid Fibrils. J Phys Chem Lett 2023:4990-4996. [PMID: 37220418 DOI: 10.1021/acs.jpclett.3c00823] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/25/2023]
Abstract
Fluorescence readouts for an amyloid fibril sensor critically depend on its molecular interaction and local environment offered by the available structural motifs. Here we employ polarized points accumulation for imaging in nanoscale topography with intramolecular charge transfer probes transiently bound to amyloid fibrils to investigate the organization of fibril nanostructures and probe binding configurations. Besides the in-plane (θ ≈ 90°) mode for binding on the fibril surface parallel to the long fibril axis, we also observed a sizable population of over 60% out-of-plane (θ < 60°) dipoles for rotor probes experiencing a varying degree of orientational mobility. Highly confined dipoles exhibiting an out-of-plane configuration probably reflect tightly bound dipoles in the inner channel grooves, while the weakly bound ones on amyloid enjoy rotational flexibility. Our observation of an out-of-plane binding mode emphasizes the pivotal role played by the electron donor amino group toward fluorescence detection and hence the emergence of anchored probes alongside conventional groove binders.
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Affiliation(s)
- Aranyak Sarkar
- Radiation & Photochemistry Division, Bhabha Atomic Research Center, Mumbai 400085, India
- Homi Bhabha National Institute, Training School Complex, Anushaktinagar, Mumbai 400094, India
| | - Vinu Namboodiri
- Radiation & Photochemistry Division, Bhabha Atomic Research Center, Mumbai 400085, India
| | - Manoj Kumbhakar
- Radiation & Photochemistry Division, Bhabha Atomic Research Center, Mumbai 400085, India
- Homi Bhabha National Institute, Training School Complex, Anushaktinagar, Mumbai 400094, India
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11
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Sun Y, Jack K, Ercolani T, Sangar D, Hosszu L, Collinge J, Bieschke J. Direct Observation of Competing Prion Protein Fibril Populations with Distinct Structures and Kinetics. ACS NANO 2023; 17:6575-6588. [PMID: 36802500 PMCID: PMC10100569 DOI: 10.1021/acsnano.2c12009] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 12/02/2022] [Accepted: 02/10/2023] [Indexed: 06/18/2023]
Abstract
In prion diseases, fibrillar assemblies of misfolded prion protein (PrP) self-propagate by incorporating PrP monomers. These assemblies can evolve to adapt to changing environments and hosts, but the mechanism of prion evolution is poorly understood. We show that PrP fibrils exist as a population of competing conformers, which are selectively amplified under different conditions and can "mutate" during elongation. Prion replication therefore possesses the steps necessary for molecular evolution analogous to the quasispecies concept of genetic organisms. We monitored structure and growth of single PrP fibrils by total internal reflection and transient amyloid binding super-resolution microscopy and detected at least two main fibril populations, which emerged from seemingly homogeneous PrP seeds. All PrP fibrils elongated in a preferred direction by an intermittent "stop-and-go" mechanism, but each population possessed distinct elongation mechanisms that incorporated either unfolded or partially folded monomers. Elongation of RML and ME7 prion rods likewise exhibited distinct kinetic features. The discovery of polymorphic fibril populations growing in competition, which were previously hidden in ensemble measurements, suggests that prions and other amyloid replicating by prion-like mechanisms may represent quasispecies of structural isomorphs that can evolve to adapt to new hosts and conceivably could evade therapeutic intervention.
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Affiliation(s)
- Yuanzi Sun
- MRC
Prion Unit at UCL/UCL Institute of Prion Diseases, University College London, London W1W 7FF, United Kingdom
| | - Kezia Jack
- MRC
Prion Unit at UCL/UCL Institute of Prion Diseases, University College London, London W1W 7FF, United Kingdom
| | - Tiziana Ercolani
- MRC
Prion Unit at UCL/UCL Institute of Prion Diseases, University College London, London W1W 7FF, United Kingdom
| | - Daljit Sangar
- MRC
Prion Unit at UCL/UCL Institute of Prion Diseases, University College London, London W1W 7FF, United Kingdom
| | - Laszlo Hosszu
- MRC
Prion Unit at UCL/UCL Institute of Prion Diseases, University College London, London W1W 7FF, United Kingdom
| | - John Collinge
- MRC
Prion Unit at UCL/UCL Institute of Prion Diseases, University College London, London W1W 7FF, United Kingdom
| | - Jan Bieschke
- MRC
Prion Unit at UCL/UCL Institute of Prion Diseases, University College London, London W1W 7FF, United Kingdom
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12
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Sun N, Jia Y, Bai S, Li Q, Dai L, Li J. The power of super-resolution microscopy in modern biomedical science. Adv Colloid Interface Sci 2023; 314:102880. [PMID: 36965225 DOI: 10.1016/j.cis.2023.102880] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2022] [Revised: 03/08/2023] [Accepted: 03/08/2023] [Indexed: 03/14/2023]
Abstract
Super-resolution microscopy (SRM) technology that breaks the diffraction limit has revolutionized the field of cell biology since its appearance, which enables researchers to visualize cellular structures with nanometric resolution, multiple colors and single-molecule sensitivity. With the flourishing development of hardware and the availability of novel fluorescent probes, the impact of SRM has already gone beyond cell biology and extended to nanomedicine, material science and nanotechnology, and remarkably boosted important breakthroughs in these fields. In this review, we will mainly highlight the power of SRM in modern biomedical science, discussing how these SRM techniques revolutionize the way we understand cell structures, biomaterials assembly and how assembled biomaterials interact with cellular organelles, and finally their promotion to the clinical pre-diagnosis. Moreover, we also provide an outlook on the current technical challenges and future improvement direction of SRM. We hope this review can provide useful information, inspire new ideas and propel the development both from the perspective of SRM techniques and from the perspective of SRM's applications.
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Affiliation(s)
- Nan Sun
- Beijing National Laboratory for Molecular Sciences (BNLMS), CAS Key Lab of Colloid, Interface and Chemical Thermodynamics, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190, China; University of Chinese Academy of Sciences, Beijing 100049
| | - Yi Jia
- Beijing National Laboratory for Molecular Sciences (BNLMS), CAS Key Lab of Colloid, Interface and Chemical Thermodynamics, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190, China.
| | - Shiwei Bai
- Beijing National Laboratory for Molecular Sciences (BNLMS), CAS Key Lab of Colloid, Interface and Chemical Thermodynamics, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190, China; University of Chinese Academy of Sciences, Beijing 100049
| | - Qi Li
- State Key Laboratory of Biochemical Engineering Institute of Process Engineering Chinese Academy of Sciences, Beijing 100190, China
| | - Luru Dai
- Wenzhou Institute and Wenzhou Key Laboratory of Biophysics, University of Chinese Academy of Sciences, Wenzhou, Zhejiang 325001, China
| | - Junbai Li
- Beijing National Laboratory for Molecular Sciences (BNLMS), CAS Key Lab of Colloid, Interface and Chemical Thermodynamics, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190, China; University of Chinese Academy of Sciences, Beijing 100049.
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13
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Gong J, Jin Z, Chen H, He J, Zhang Y, Yang X. Super-resolution fluorescence microscopic imaging in pathogenesis and drug treatment of neurological disease. Adv Drug Deliv Rev 2023; 196:114791. [PMID: 37004939 DOI: 10.1016/j.addr.2023.114791] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2022] [Revised: 03/16/2023] [Accepted: 03/19/2023] [Indexed: 04/03/2023]
Abstract
Since super-resolution fluorescence microscopic technology breaks the diffraction limit that has existed for a long time in optical imaging, it can observe the process of synapses formed between nerve cells and the protein aggregation related to neurological disease. Thus, super-resolution fluorescence microscopic imaging has significantly impacted several industries, including drug development and pathogenesis research, and it is anticipated that it will significantly alter the future of life science research. Here, we focus on several typical super-resolution fluorescence microscopic technologies, introducing their benefits and drawbacks, as well as applications in several common neurological diseases, in the hope that their services will be expanded and improved in the pathogenesis and drug treatment of neurological diseases.
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14
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Nosova O, Guselnikova V, Korzhevskii D. The application of alcian blue to identify astrocyte-associated amyloid plaques by using fluorescence and confocal microscopy. J Neurosci Methods 2023; 387:109797. [PMID: 36682730 DOI: 10.1016/j.jneumeth.2023.109797] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2022] [Revised: 01/15/2023] [Accepted: 01/18/2023] [Indexed: 01/21/2023]
Abstract
BACKGROUND Astrocytes play an essential role in the normal functioning of the nervous system and are active contributors to the pathogenesis of neurodegenerative diseases such as Alzheimer's disease (AD). Therefore, to comprehend the astrocytes and amyloid plaques relationship there is a need for imaging techniques providing simultaneous visualization of astrocytes using fluorescence and amyloid plaques revealed by transmitted light microscopy. NEW METHOD The possibility of simultaneous detection of astrocytes by immunocytochemistry (fluorescent) and amyloid plaques by cytochemical Alcian Blue (transparent) using confocal microscopy in 8-month-old 5хFAD mice samples shown. RESULTS The described method supposes performing astrocytes fluorescent labelling by GFAP or S100beta and amyloid plaques staining by Alcian Blue. COMPARISON WITH EXISTING METHODS Proposed approach circumvents some limitations of fluorescence microscopy, such as weak fluorescence, low contrast, fluorophore broad excitation/emission profile and chemical instability. CONCLUSIONS The proposed technique provides high-quality resulting images of GFAP/s100beta- labelled astrocytes and Alcian Blue-stained amyloid plaques. These images are appliable for prospective qualitative and quantitative three-dimensional analysis due to the z-axis scanning. Moreover, it demonstrated the formation of stable Alcian Blue staining.
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Affiliation(s)
- Olga Nosova
- Institute of Experimental Medicine, St. Petersburg 197376, Russia.
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15
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Quantitative super-resolution imaging of pathological aggregates reveals distinct toxicity profiles in different synucleinopathies. Proc Natl Acad Sci U S A 2022; 119:e2205591119. [PMID: 36206368 PMCID: PMC9573094 DOI: 10.1073/pnas.2205591119] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023] Open
Abstract
Protein aggregation is a hallmark of major neurodegenerative disorders. Increasing data suggest that smaller aggregates cause higher toxic response than filamentous aggregates (fibrils). However, the size of small aggregates has challenged their detection within biologically relevant environments. Here, we report approaches to quantitatively super-resolve aggregates in live cells and ex vivo brain tissues. We show that Amytracker 630 (AT630), a commercial aggregate-activated fluorophore, has outstanding photophysical properties that enable super-resolution imaging of α-synuclein, tau, and amyloid-β aggregates, achieving ∼4 nm precision. Applying AT630 to AppNL-G-F mouse brain tissues or aggregates extracted from a Parkinson's disease donor, we demonstrate excellent agreement with antibodies specific for amyloid-β or α-synuclein, respectively, confirming the specificity of AT630. Subsequently, we use AT630 to reveal a linear relationship between α-synuclein aggregate size and cellular toxicity and discovered that aggregates smaller than 450 ± 60 nm (aggregate450nm) readily penetrated the plasma membrane. We determine aggregate450nm concentrations in six Parkinson's disease and dementia with Lewy bodies donor samples and show that aggregates in different synucleinopathies demonstrate distinct potency in toxicity. We further show that cell-penetrating aggregates are surrounded by proteasomes, which assemble into foci to gradually process aggregates. Our results suggest that the plasma membrane effectively filters out fibrils but is vulnerable to penetration by aggregates of 450 ± 60 nm. Together, our findings present an exciting strategy to determine specificity of aggregate toxicity within heterogeneous samples. Our approach to quantitatively measure these toxic aggregates in biological environments opens possibilities to molecular examinations of disease mechanisms under physiological conditions.
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16
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Small soluble α-synuclein aggregates are the toxic species in Parkinson's disease. Nat Commun 2022; 13:5512. [PMID: 36127374 PMCID: PMC9489799 DOI: 10.1038/s41467-022-33252-6] [Citation(s) in RCA: 50] [Impact Index Per Article: 25.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2022] [Accepted: 09/08/2022] [Indexed: 11/08/2022] Open
Abstract
Soluble α-synuclein aggregates varying in size, structure, and morphology have been closely linked to neuronal death in Parkinson's disease. However, the heterogeneity of different co-existing aggregate species makes it hard to isolate and study their individual toxic properties. Here, we show a reliable non-perturbative method to separate a heterogeneous mixture of protein aggregates by size. We find that aggregates of wild-type α-synuclein smaller than 200 nm in length, formed during an in vitro aggregation reaction, cause inflammation and permeabilization of single-liposome membranes and that larger aggregates are less toxic. Studying soluble aggregates extracted from post-mortem human brains also reveals that these aggregates are similar in size and structure to the smaller aggregates formed in aggregation reactions in the test tube. Furthermore, we find that the soluble aggregates present in Parkinson's disease brains are smaller, largely less than 100 nm, and more inflammatory compared to the larger aggregates present in control brains. This study suggests that the small non-fibrillar α-synuclein aggregates are the critical species driving neuroinflammation and disease progression.
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17
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Torra J, Viela F, Megías D, Sot B, Flors C. Versatile Near‐Infrared Super‐Resolution Imaging of Amyloid Fibrils with the Fluorogenic Probe CRANAD‐2. Chemistry 2022; 28:e202200026. [DOI: 10.1002/chem.202200026] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2022] [Indexed: 11/06/2022]
Affiliation(s)
- Joaquim Torra
- Madrid Institute for Advanced Studies in Nanoscience (IMDEA Nanociencia) Madrid 28049 Spain
| | - Felipe Viela
- Madrid Institute for Advanced Studies in Nanoscience (IMDEA Nanociencia) Madrid 28049 Spain
| | - Diego Megías
- Confocal Microscopy Unit; Biotechnology Programme Spanish National Cancer Research Centre (CNIO) Madrid 28029 Spain
| | - Begoña Sot
- Madrid Institute for Advanced Studies in Nanoscience (IMDEA Nanociencia) Madrid 28049 Spain
- Nanobiotechnology Unit Associated to the National Center for Biotechnology (CNB-CSIC-IMDEA) Madrid 28049 Spain
| | - Cristina Flors
- Madrid Institute for Advanced Studies in Nanoscience (IMDEA Nanociencia) Madrid 28049 Spain
- Nanobiotechnology Unit Associated to the National Center for Biotechnology (CNB-CSIC-IMDEA) Madrid 28049 Spain
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18
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Tempra C, Scollo F, Pannuzzo M, Lolicato F, La Rosa C. A unifying framework for amyloid-mediated membrane damage: The lipid-chaperone hypothesis. BIOCHIMICA ET BIOPHYSICA ACTA. PROTEINS AND PROTEOMICS 2022; 1870:140767. [PMID: 35144022 DOI: 10.1016/j.bbapap.2022.140767] [Citation(s) in RCA: 14] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/24/2021] [Revised: 01/31/2022] [Accepted: 02/01/2022] [Indexed: 12/16/2022]
Abstract
Over the past thirty years, researchers have highlighted the role played by a class of proteins or polypeptides that forms pathogenic amyloid aggregates in vivo, including i) the amyloid Aβ peptide, which is known to form senile plaques in Alzheimer's disease; ii) α-synuclein, responsible for Lewy body formation in Parkinson's disease and iii) IAPP, which is the protein component of type 2 diabetes-associated islet amyloids. These proteins, known as intrinsically disordered proteins (IDPs), are present as highly dynamic conformational ensembles. IDPs can partially (mis) fold into (dys) functional conformations and accumulate as amyloid aggregates upon interaction with other cytosolic partners such as proteins or lipid membranes. In addition, an increasing number of reports link the toxicity of amyloid proteins to their harmful effects on membrane integrity. Still, the molecular mechanism underlying the amyloidogenic proteins transfer from the aqueous environment to the hydrocarbon core of the membrane is poorly understood. This review starts with a historical overview of the toxicity models of amyloidogenic proteins to contextualize the more recent lipid-chaperone hypothesis. Then, we report the early molecular-level events in the aggregation and ion-channel pore formation of Aβ, IAPP, and α-synuclein interacting with model membranes, emphasizing the complexity of these processes due to their different spatial-temporal resolutions. Next, we underline the need for a combined experimental and computational approach, focusing on the strengths and weaknesses of the most commonly used techniques. Finally, the last two chapters highlight the crucial role of lipid-protein complexes as molecular switches among ion-channel-like formation, detergent-like, and fibril formation mechanisms and their implication in fighting amyloidogenic diseases.
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Affiliation(s)
- Carmelo Tempra
- Institute of Organic Chemistry and Biochemistry, Prague, Czech Republic
| | - Federica Scollo
- J. Heyrovský Institute of Physical Chemistry, Czech Academy of Sciences, Prague, Czech Republic
| | - Martina Pannuzzo
- Laboratory of Nanotechnology for Precision Medicine, Fondazione Istituto Italiano di Tecnologia, Genoa, Italy
| | - Fabio Lolicato
- Heidelberg University Biochemistry Center, Heidelberg, Germany; Department of Physics, University of Helsinki, Helsinki, Finland.
| | - Carmelo La Rosa
- Dipartimento di Scienze Chimiche, Università degli Studi di Catania, Catania, Italy.
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19
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Kaur A, Adair LD, Ball SR, New EJ, Sunde M. A Fluorescent Sensor for Quantitative Super‐Resolution Imaging of Amyloid Fibril Assembly**. Angew Chem Int Ed Engl 2022. [DOI: 10.1002/ange.202112832] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
- Amandeep Kaur
- School of Medical Sciences Faculty of Medicine and Health The University of Sydney Sydney NSW 2006 Australia
- The University of Sydney Nano Institute The University of Sydney Sydney NSW 2006 Australia
| | - Liam D. Adair
- School of Chemistry The University of Sydney Sydney NSW 2006 Australia
- Australian Research Council Centre of Excellence for Innovations in Peptide and Protein Science The University of Sydney Sydney NSW 2006 Australia
| | - Sarah R. Ball
- School of Medical Sciences Faculty of Medicine and Health The University of Sydney Sydney NSW 2006 Australia
| | - Elizabeth J. New
- The University of Sydney Nano Institute The University of Sydney Sydney NSW 2006 Australia
- School of Chemistry The University of Sydney Sydney NSW 2006 Australia
- Australian Research Council Centre of Excellence for Innovations in Peptide and Protein Science The University of Sydney Sydney NSW 2006 Australia
| | - Margaret Sunde
- School of Medical Sciences Faculty of Medicine and Health The University of Sydney Sydney NSW 2006 Australia
- The University of Sydney Nano Institute The University of Sydney Sydney NSW 2006 Australia
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20
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Kaur A, Adair LD, Ball SR, New EJ, Sunde M. A Fluorescent Sensor for Quantitative Super-resolution Imaging of Amyloid Fibril Assembly. Angew Chem Int Ed Engl 2021; 61:e202112832. [PMID: 34935241 DOI: 10.1002/anie.202112832] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2021] [Indexed: 11/07/2022]
Abstract
Many soluble proteins can self-assemble into macromolecular structures called amyloids, a subset of which are implicated in a range of neurodegenerative disorders. The nanoscale size and structural heterogeneity of prefibrillar and early aggregates, as well as mature amyloid fibrils, pose significant challenges for the quantification of amyloid species, identification of their cellular interaction partners and for elucidation of the molecular basis for cytotoxicity. We report a fluorescent amyloid sensor AmyBlink-1 and its application in super-resolution imaging of amyloid structures. AmyBlink-1 exhibits a 5-fold increase in ratio of the green (thioflavin T) to red (Alexa Fluor 647) emission intensities upon interaction with amyloid fibrils. Using AmyBlink-1 , we performed nanoscale imaging of four different types of amyloid fibrils, achieving a resolution of ~30 nm. AmyBlink-1 enables nanoscale visualization and subsequent quantification of morphological features, such as the length and skew of individual amyloid aggregates formed at different times along the amyloid assembly pathway.
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Affiliation(s)
- Amandeep Kaur
- University of Sydney, School.of Medical Sciences, University of Sydney, 2006, Sydney, AUSTRALIA
| | - Liam D Adair
- The University of Sydney, School of Chemistry, AUSTRALIA
| | - Sarah R Ball
- The University of Sydney, School of Medical Sciences, AUSTRALIA
| | | | - Margaret Sunde
- The University of Sydney, School of Medical Sciences, AUSTRALIA
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21
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Ding T, Lew MD. Single-Molecule Localization Microscopy of 3D Orientation and Anisotropic Wobble Using a Polarized Vortex Point Spread Function. J Phys Chem B 2021; 125:12718-12729. [PMID: 34766758 PMCID: PMC8662813 DOI: 10.1021/acs.jpcb.1c08073] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
Within condensed matter, single fluorophores are sensitive probes of their chemical environments, but it is difficult to use their limited photon budget to image precisely their positions, 3D orientations, and rotational diffusion simultaneously. We demonstrate the polarized vortex point spread function (PSF) for measuring these parameters, including characterizing the anisotropy of a molecule's wobble, simultaneously from a single image. Even when imaging dim emitters (∼500 photons detected), the polarized vortex PSF can obtain 12 nm localization precision, 4°-8° orientation precision, and 26° wobble precision. We use the vortex PSF to measure the emission anisotropy of fluorescent beads, the wobble dynamics of Nile red (NR) within supported lipid bilayers, and the distinct orientation signatures of NR in contact with amyloid-beta fibrils, oligomers, and tangles. The unparalleled sensitivity of the vortex PSF transforms single-molecule microscopes into nanoscale orientation imaging spectrometers, where the orientations and wobbles of individual probes reveal structures and organization of soft matter that are nearly impossible to perceive by using molecular positions alone.
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Affiliation(s)
- Tianben Ding
- Department of Electrical and Systems Engineering, Washington University in St. Louis, St. Louis, Missouri 63130, United States
- Center for Science and Engineering of Living Systems, Washington University in St. Louis, St. Louis, Missouri 63130, United States
| | - Matthew D Lew
- Department of Electrical and Systems Engineering, Washington University in St. Louis, St. Louis, Missouri 63130, United States
- Center for Science and Engineering of Living Systems, Washington University in St. Louis, St. Louis, Missouri 63130, United States
- Institute of Materials Science and Engineering, Washington University in St. Louis, St. Louis, Missouri 63130, United States
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22
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Das A, Korn A, Carroll A, Carver JA, Maiti S. Application of the Double-Mutant Cycle Strategy to Protein Aggregation Reveals Transient Interactions in Amyloid-β Oligomers. J Phys Chem B 2021; 125:12426-12435. [PMID: 34748334 DOI: 10.1021/acs.jpcb.1c05829] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
Transient oligomeric intermediates in the peptide or protein aggregation pathway are suspected to be the key toxic species in many amyloid diseases, but deciphering their molecular nature has remained a challenge. Here we show that the strategy of "double-mutant cycles", used effectively in probing protein-folding intermediates, can reveal transient interactions during protein aggregation. It does so by comparing the changes in thermodynamic parameters between the wild type, and single and double mutants. We demonstrate the strategy by probing the possible transient salt bridge partner of lysine 28 (K28) in the oligomeric states of amyloid β-40 (Aβ40), the putative toxic species in Alzheimer's disease. In mature fibrils, the binding partner is aspartate 23. This interaction differentiates Aβ40 from the more toxic Aβ42, where K28's binding partner is the C-terminal carboxylate. We selectively acetylated K28 and amidated the C-terminus of Aβ40, creating four distinct variants. Spectroscopic measurements of the kinetics and thermodynamics of aggregation show that K28 and the C-terminus interact transiently in the early phases of the Aβ40 aggregation pathway. Hydrogen-deuterium exchange mass spectrometry (using a simple analysis method that we introduce here that takes into account the isotopic mass distribution) supports this interpretation. It is also supported by cellular toxicity measurements, suggesting possible similarities in the mechanisms of toxicity of Aβ40 oligomers (which are more toxic than Aβ40 fibrils) and Aβ42. Our results show that double-mutant cycles can be a powerful tool for probing transient interactions during protein aggregation.
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Affiliation(s)
- Anirban Das
- Department of Chemical Sciences, Tata Institute of Fundamental Research, Homi Bhabha Road, Colaba, Mumbai 400005, India
| | - Alexander Korn
- Institute for Medical Physics and Biophysics, Leipzig University, Härtelstr. 16-18, D-04107 Leipzig, Germany
| | - Adam Carroll
- Research School of Chemistry, The Australian National University, Acton, Australian Capital Territory 2601, Australia
| | - John A Carver
- Research School of Chemistry, The Australian National University, Acton, Australian Capital Territory 2601, Australia
| | - Sudipta Maiti
- Department of Chemical Sciences, Tata Institute of Fundamental Research, Homi Bhabha Road, Colaba, Mumbai 400005, India
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23
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Super-resolution microscopy: a closer look at synaptic dysfunction in Alzheimer disease. Nat Rev Neurosci 2021; 22:723-740. [PMID: 34725519 DOI: 10.1038/s41583-021-00531-y] [Citation(s) in RCA: 26] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 09/27/2021] [Indexed: 11/08/2022]
Abstract
The synapse has emerged as a critical neuronal structure in the degenerative process of Alzheimer disease (AD), in which the pathogenic signals of two key players - amyloid-β (Aβ) and tau - converge, thereby causing synaptic dysfunction and cognitive deficits. The synapse presents a dynamic, confined microenvironment in which to explore how key molecules travel, localize, interact and assume different levels of organizational complexity, thereby affecting neuronal function. However, owing to their small size and the diffraction-limited resolution of conventional light microscopic approaches, investigating synaptic structure and dynamics has been challenging. Super-resolution microscopy (SRM) techniques have overcome the resolution barrier and are revolutionizing our quantitative understanding of biological systems in unprecedented spatio-temporal detail. Here we review critical new insights provided by SRM into the molecular architecture and dynamic organization of the synapse and, in particular, the interactions between Aβ and tau in this compartment. We further highlight how SRM can transform our understanding of the molecular pathological mechanisms that underlie AD. The application of SRM for understanding the roles of synapses in AD pathology will provide a stepping stone towards a broader understanding of dysfunction in other subcellular compartments and at cellular and circuit levels in this disease.
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24
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Abstract
Fluorescence imaging techniques play a pivotal role in our understanding of the nervous system. The emergence of various super-resolution microscopy methods and specialized fluorescent probes enables direct insight into neuronal structure and protein arrangements in cellular subcompartments with so far unmatched resolution. Super-resolving visualization techniques in neurons unveil a novel understanding of cytoskeletal composition, distribution, motility, and signaling of membrane proteins, subsynaptic structure and function, and neuron-glia interaction. Well-defined molecular targets in autoimmune and neurodegenerative disease models provide excellent starting points for in-depth investigation of disease pathophysiology using novel and innovative imaging methodology. Application of super-resolution microscopy in human brain samples and for testing clinical biomarkers is still in its infancy but opens new opportunities for translational research in neurology and neuroscience. In this review, we describe how super-resolving microscopy has improved our understanding of neuronal and brain function and dysfunction in the last two decades.
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Affiliation(s)
- Christian Werner
- Department of Biotechnology & Biophysics, Biocenter, University of Würzburg, 97074 Würzburg, Germany
| | - Markus Sauer
- Department of Biotechnology & Biophysics, Biocenter, University of Würzburg, 97074 Würzburg, Germany
| | - Christian Geis
- Section Translational Neuroimmunology, Department of Neurology, Jena University Hospital, Am Klinikum 1, 07747 Jena, Germany
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25
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Bondia P, Flors C, Torra J. Boosting the inactivation of bacterial biofilms by photodynamic targeting of matrix structures with Thioflavin T. Chem Commun (Camb) 2021; 57:8648-8651. [PMID: 34369943 DOI: 10.1039/d1cc03155d] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
We report that Thioflavin T (ThT), the reference fluorogenic probe for amyloid detection, displays photodynamic activity against bacterial biofilms. ThT recognizes key structures of the biofilm matrix, disrupting the complex architecture and efficiently inactivating bacterial cells. We also show that ThT phototherapy synergistically boosts the activity of conventional antimicrobials.
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Affiliation(s)
- Patricia Bondia
- Madrid Institute for Advanced Studies in Nanoscience (IMDEA Nanociencia), Madrid, Spain.
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26
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Single Molecule Characterization of Amyloid Oligomers. Molecules 2021; 26:molecules26040948. [PMID: 33670093 PMCID: PMC7916856 DOI: 10.3390/molecules26040948] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2020] [Revised: 01/29/2021] [Accepted: 02/02/2021] [Indexed: 12/11/2022] Open
Abstract
The misfolding and aggregation of polypeptide chains into β-sheet-rich amyloid fibrils is associated with a wide range of neurodegenerative diseases. Growing evidence indicates that the oligomeric intermediates populated in the early stages of amyloid formation rather than the mature fibrils are responsible for the cytotoxicity and pathology and are potentially therapeutic targets. However, due to the low-populated, transient, and heterogeneous nature of amyloid oligomers, they are hard to characterize by conventional bulk methods. The development of single molecule approaches provides a powerful toolkit for investigating these oligomeric intermediates as well as the complex process of amyloid aggregation at molecular resolution. In this review, we present an overview of recent progress in characterizing the oligomerization of amyloid proteins by single molecule fluorescence techniques, including single-molecule Förster resonance energy transfer (smFRET), fluorescence correlation spectroscopy (FCS), single-molecule photobleaching and super-resolution optical imaging. We discuss how these techniques have been applied to investigate the different aspects of amyloid oligomers and facilitate understanding of the mechanism of amyloid aggregation.
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27
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Mazidi H, Ding T, Nehorai A, Lew MD. Quantifying accuracy and heterogeneity in single-molecule super-resolution microscopy. Nat Commun 2020; 11:6353. [PMID: 33311471 PMCID: PMC7732856 DOI: 10.1038/s41467-020-20056-9] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2020] [Accepted: 11/10/2020] [Indexed: 12/03/2022] Open
Abstract
The resolution and accuracy of single-molecule localization microscopes (SMLMs) are routinely benchmarked using simulated data, calibration rulers, or comparisons to secondary imaging modalities. However, these methods cannot quantify the nanoscale accuracy of an arbitrary SMLM dataset. Here, we show that by computing localization stability under a well-chosen perturbation with accurate knowledge of the imaging system, we can robustly measure the confidence of individual localizations without ground-truth knowledge of the sample. We demonstrate that our method, termed Wasserstein-induced flux (WIF), measures the accuracy of various reconstruction algorithms directly on experimental 2D and 3D data of microtubules and amyloid fibrils. We further show that WIF confidences can be used to evaluate the mismatch between computational models and imaging data, enhance the accuracy and resolution of reconstructed structures, and discover hidden molecular heterogeneities. As a computational methodology, WIF is broadly applicable to any SMLM dataset, imaging system, and localization algorithm. Standard benchmarking of single-molecule localization microscopy cannot quantify nanoscale accuracy of arbitrary datasets. Here, the authors present Wasserstein-induced flux, a method using a chosen perturbation and knowledge of the imaging system to measure confidence of individual localizations.
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Affiliation(s)
- Hesam Mazidi
- Department of Electrical and Systems Engineering, Washington University in St. Louis, St. Louis, MO, 63130, USA
| | - Tianben Ding
- Department of Electrical and Systems Engineering, Washington University in St. Louis, St. Louis, MO, 63130, USA
| | - Arye Nehorai
- Department of Electrical and Systems Engineering, Washington University in St. Louis, St. Louis, MO, 63130, USA
| | - Matthew D Lew
- Department of Electrical and Systems Engineering, Washington University in St. Louis, St. Louis, MO, 63130, USA.
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28
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Needham LM, Weber J, Pearson CM, Do DT, Gorka F, Lyu G, Bohndiek SE, Snaddon TN, Lee SF. A Comparative Photophysical Study of Structural Modifications of Thioflavin T-Inspired Fluorophores. J Phys Chem Lett 2020; 11:8406-8416. [PMID: 32924494 PMCID: PMC8741274 DOI: 10.1021/acs.jpclett.0c01549] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/26/2023]
Abstract
The benzothiazolium salt, Thioflavin T (ThT), has been widely adopted as the "gold-standard" fluorescent reporter of amyloid in vitro. Its properties as a molecular rotor result in a large-scale (∼1000-fold) fluorescence turn-on upon binding to β-sheets in amyloidogenic proteins. However, the complex photophysics of ThT combined with the intricate and varied nature of the amyloid binding motif means these interactions are poorly understood. To study this important class of fluorophores, we present a detailed photophysical characterization and comparison of a novel library of 12 ThT-inspired fluorescent probes for amyloid protein (PAPs), where both the charge and donor capacity of the heterocyclic and aminobenzene components have been interrogated, respectively. This enables direct photophysical juxtaposition of two structural groups: the neutral "PAP" (class 1) and the charged "mPAP" fluorophores (class 2). We quantify binding and optical properties at both the bulk and single-aggregate levels with some derivatives showing higher aggregate affinity and brightness than ThT. Finally, we demonstrate their abilities to perform super-resolution imaging of α-synuclein fibrils with localization precisions of ∼16 nm. The properties of the derivatives provide new insights into the relationship between chemical structure and function of benzothiazole probes.
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Affiliation(s)
- Lisa-Maria Needham
- Department of Chemistry, University of Cambridge, Cambridge CB2 1EW, U.K
| | - Judith Weber
- Department of Chemistry, University of Cambridge, Cambridge CB2 1EW, U.K
- Department of Physics, University of Cambridge, Cambridge CB3 0HE, U.K
- Cancer Research UK Cambridge Institute, University of Cambridge, Cambridge CB2 0RE, U.K
| | - Colin M Pearson
- Department of Chemistry, Indiana University, Bloomington, Indiana 47405, United States
| | - Dung T Do
- Department of Chemistry, Indiana University, Bloomington, Indiana 47405, United States
| | - Felix Gorka
- Department of Chemistry, University of Cambridge, Cambridge CB2 1EW, U.K
| | - Guanpeng Lyu
- Department of Chemistry, University of Cambridge, Cambridge CB2 1EW, U.K
| | - Sarah E Bohndiek
- Department of Physics, University of Cambridge, Cambridge CB3 0HE, U.K
| | - Thomas N Snaddon
- Department of Chemistry, Indiana University, Bloomington, Indiana 47405, United States
| | - Steven F Lee
- Department of Chemistry, University of Cambridge, Cambridge CB2 1EW, U.K
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29
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Kaur A, New EJ, Sunde M. Strategies for the Molecular Imaging of Amyloid and the Value of a Multimodal Approach. ACS Sens 2020; 5:2268-2282. [PMID: 32627533 DOI: 10.1021/acssensors.0c01101] [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] [Indexed: 02/08/2023]
Abstract
Protein aggregation has been widely implicated in neurodegenerative diseases such as Alzheimer's disease, frontotemporal dementia, Parkinson's disease, and Huntington disease, as well as in systemic amyloidoses and conditions associated with localized amyloid deposits, such as type-II diabetes. The pressing need for a better understanding of the factors governing protein assembly has driven research for the development of molecular sensors for amyloidogenic proteins. To date, a number of sensors have been developed that report on the presence of protein aggregates utilizing various modalities, and their utility demonstrated for imaging protein aggregation in vitro and in vivo. Analysis of these sensors highlights the various advantages and disadvantages of the different imaging modalities and makes clear that multimodal sensors with properties amenable to more than one imaging technique need to be developed. This critical review highlights the key molecular scaffolds reported for molecular imaging modalities such as fluorescence, positron emission tomography, single photon emission computed tomography, and magnetic resonance imaging and includes discussion of the advantages and disadvantages of each modality, and future directions for the design of amyloid sensors. We also discuss the recent efforts focused on the design and development of multimodal sensors and the value of cross-validation across multiple modalities.
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Affiliation(s)
- Amandeep Kaur
- The University of Sydney, School of Medical Sciences, Faculty of Medicine and Health, Sydney, New South Wales 2006, Australia
- The University of Sydney, Nano Institute (Sydney Nano), The University of Sydney, Sydney, New South Wales 2006, Australia
| | - Elizabeth J. New
- The University of Sydney, Nano Institute (Sydney Nano), The University of Sydney, Sydney, New South Wales 2006, Australia
- The University of Sydney, School of Chemistry, Faculty of Science, Sydney, New South Wales 2006, Australia
- Australian Research Council Centre of Excellence for Innovations in Peptide and Protein Science, The University of Sydney, Sydney, New South Wales 2006, Australia
| | - Margaret Sunde
- The University of Sydney, School of Medical Sciences, Faculty of Medicine and Health, Sydney, New South Wales 2006, Australia
- The University of Sydney, Nano Institute (Sydney Nano), The University of Sydney, Sydney, New South Wales 2006, Australia
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30
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Torra J, Bondia P, Gutierrez-Erlandsson S, Sot B, Flors C. Long-term STED imaging of amyloid fibers with exchangeable Thioflavin T. NANOSCALE 2020; 12:15050-15053. [PMID: 32666991 DOI: 10.1039/d0nr02961k] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
We report the use of the amyloid probe Thioflavin T (ThT) as a specific and exchangeable fluorophore for stimulated emission depletion (STED) super-resolution imaging of amyloid fibers. This method achieves a spatial resolution in the range of 60-70 nm, low image background and increased photostability that enables long-term STED imaging. These results expand the widespread uses of ThT and can be potentially extended to other common amyloid fluorescent probes, providing new tools for the study of amyloid diseases.
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Affiliation(s)
- Joaquim Torra
- Madrid Institute for Advanced Studies in Nanoscience (IMDEA Nanociencia), Madrid, Spain.
| | - Patricia Bondia
- Madrid Institute for Advanced Studies in Nanoscience (IMDEA Nanociencia), Madrid, Spain.
| | | | - Begoña Sot
- Madrid Institute for Advanced Studies in Nanoscience (IMDEA Nanociencia), Madrid, Spain. and Unidad Asociada en Nanobiotecnología (CNB-CSIC-IMDEA Nanociencia), Madrid, Spain
| | - Cristina Flors
- Madrid Institute for Advanced Studies in Nanoscience (IMDEA Nanociencia), Madrid, Spain. and Unidad Asociada en Nanobiotecnología (CNB-CSIC-IMDEA Nanociencia), Madrid, Spain
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31
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Ding T, Wu T, Mazidi H, Zhang O, Lew MD. Single-molecule orientation localization microscopy for resolving structural heterogeneities between amyloid fibrils. OPTICA 2020; 7:602-607. [PMID: 32832582 PMCID: PMC7440617 DOI: 10.1364/optica.388157] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/07/2023]
Abstract
Simultaneous measurements of single-molecule positions and orientations provide critical insight into a variety of biological and chemical processes. Various engineered point spread functions (PSFs) have been introduced for measuring the orientation and rotational diffusion of dipole-like emitters, but the widely used Cramér-Rao bound (CRB) only evaluates performance for one specific orientation at a time. Here, we report a performance metric, termed variance upper bound (VUB), that yields a global maximum CRB for all possible molecular orientations, thereby enabling the measurement performance of any PSF to be computed efficiently (~1000× faster than calculating average CRB). Our VUB reveals that the simple polarized standard PSF provides robust and precise orientation measurements if emitters are near a refractive index interface. Using this PSF, we measure the orientations and positions of Nile red (NR) molecules transiently bound to amyloid aggregates. Our super-resolved images reveal the main binding mode of NR on amyloid fiber surfaces, as well as structural heterogeneities along amyloid fibrillar networks, that cannot be resolved by single-molecule localization alone.
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Affiliation(s)
- Tianben Ding
- Department of Electrical and Systems Engineering, Washington University in St. Louis, Missouri 63130, USA
- Center for Science and Engineering of Living Systems, Washington University in St. Louis, Missouri 63130, USA
| | - Tingting Wu
- Department of Electrical and Systems Engineering, Washington University in St. Louis, Missouri 63130, USA
- Center for Science and Engineering of Living Systems, Washington University in St. Louis, Missouri 63130, USA
| | - Hesam Mazidi
- Department of Electrical and Systems Engineering, Washington University in St. Louis, Missouri 63130, USA
- Center for Science and Engineering of Living Systems, Washington University in St. Louis, Missouri 63130, USA
| | - Oumeng Zhang
- Department of Electrical and Systems Engineering, Washington University in St. Louis, Missouri 63130, USA
- Center for Science and Engineering of Living Systems, Washington University in St. Louis, Missouri 63130, USA
| | - Matthew D. Lew
- Department of Electrical and Systems Engineering, Washington University in St. Louis, Missouri 63130, USA
- Center for Science and Engineering of Living Systems, Washington University in St. Louis, Missouri 63130, USA
- Institute of Materials Science and Engineering, Washington University in St. Louis, Missouri 63130, USA
- Corresponding author:
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32
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Das A, Gupta A, Hong Y, Carver JA, Maiti S. A Spectroscopic Marker for Structural Transitions Associated with Amyloid-β Aggregation. Biochemistry 2020; 59:1813-1822. [PMID: 32329604 DOI: 10.1021/acs.biochem.0c00113] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
An amyloid aggregate evolves through a series of intermediates that have different secondary structures and intra- and intermolecular contacts. The structural parameters of these intermediates are important determinants of their toxicity. For example, the early oligomeric species of the amyloid-β (Aβ) peptide have been implicated as the most cytotoxic species in Alzheimer's disease but are difficult to identify because of their dynamic and transitory nature. Conventional aggregation monitors such as the fluorescent dye thioflavin T report on only the overall transition of the soluble species to the final amyloid fibrillar aggregated state. Here, we show that the fluorescent dye bis(triphenylphosphonium) tetraphenylethene (TPE-TPP) identifies at least three distinct aggregation intermediates of Aβ. Some atomic-level features of these intermediates are known from solid state nuclear magnetic resonance spectroscopy. Hence, the TPE-TPP fluorescence data may be interpreted in terms of these Aβ structural transitions. Steady state fluorescence and lifetime characteristics of TPE-TPP distinguish between the small oligomeric species (emission wavelength maximum, λmax = 465 nm; average fluorescence lifetime, τFl measured at 420 nm = 3.58 ± 0.04 ns), the intermediate species (λmax = 452 nm; τFl = 3.00 ± 0.03 ns), and the fibrils (λmax = 406 nm; τFl = 5.19 ± 0.08 ns). Thus, TPE-TPP provides a ready diagnostic for differentiating between the various, including the toxic, Aβ aggregates and potentially can be utilized to screen for amyloid aggregation inhibitors.
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Affiliation(s)
- Anirban Das
- Department of Chemical Sciences, Tata Institute of Fundamental Research, Homi Bhabha Road, Colaba, Mumbai 400005, India
| | - Ankur Gupta
- Department of Chemical Sciences, Tata Institute of Fundamental Research, Homi Bhabha Road, Colaba, Mumbai 400005, India
| | - Yuning Hong
- Department of Chemistry and Physics, La Trobe Institute for Molecular Science, La Trobe University, Bundoora, VIC 3086, Australia
| | - John A Carver
- Research School of Chemistry, The Australian National University, Acton, ACT 2601, Australia
| | - Sudipta Maiti
- Department of Chemical Sciences, Tata Institute of Fundamental Research, Homi Bhabha Road, Colaba, Mumbai 400005, India
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33
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Needham LM, Weber J, Varela JA, Fyfe JWB, Do DT, Xu CK, Tutton L, Cliffe R, Keenlyside B, Klenerman D, Dobson CM, Hunter CA, Müller KH, O'Holleran K, Bohndiek SE, Snaddon TN, Lee SF. ThX - a next-generation probe for the early detection of amyloid aggregates. Chem Sci 2020; 11:4578-4583. [PMID: 34122915 PMCID: PMC8159457 DOI: 10.1039/c9sc04730a] [Citation(s) in RCA: 37] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023] Open
Abstract
Neurodegenerative diseases such as Alzheimer's and Parkinson's are associated with protein misfolding and aggregation. Recent studies suggest that the small, rare and heterogeneous oligomeric species, formed early on in the aggregation process, may be a source of cytotoxicity. Thioflavin T (ThT) is currently the gold-standard fluorescent probe for the study of amyloid proteins and aggregation processes. However, the poor photophysical and binding properties of ThT impairs the study of oligomers. To overcome this challenge, we have designed Thioflavin X, (ThX), a next-generation fluorescent probe which displays superior properties; including a 5-fold increase in brightness and 7-fold increase in binding affinity to amyloidogenic proteins. As an extrinsic dye, this can be used to study unique structural amyloid features both in bulk and on a single-aggregate level. Furthermore, ThX can be used as a super-resolution imaging probe in single-molecule localisation microscopy. Finally, the improved optical properties (extinction coefficient, quantum yield and brightness) of ThX can be used to monitor structural differences in oligomeric species, not observed via traditional ThT imaging.
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Affiliation(s)
| | - Judith Weber
- Department of Chemistry, University of Cambridge Cambridge CB2 1EW UK .,Department of Physics, University of Cambridge Cambridge CB3 0HE UK.,Cancer Research UK Cambridge Institute, University of Cambridge Cambridge CB2 0RE UK
| | - Juan A Varela
- Biomedical Sciences Research Complex, School of Biology, University of St Andrews St Andrews UK
| | - James W B Fyfe
- Department of Chemistry, Indiana University Bloomington 47405 USA
| | - Dung T Do
- Department of Chemistry, Indiana University Bloomington 47405 USA
| | - Catherine K Xu
- Department of Chemistry, University of Cambridge Cambridge CB2 1EW UK
| | - Luke Tutton
- Department of Chemistry, University of Cambridge Cambridge CB2 1EW UK
| | - Rachel Cliffe
- Department of Chemistry, University of Cambridge Cambridge CB2 1EW UK
| | | | - David Klenerman
- Department of Chemistry, University of Cambridge Cambridge CB2 1EW UK
| | | | | | - Karin H Müller
- Cambridge Advanced Imaging Centre, University of Cambridge Cambridge CB2 3DY UK
| | - Kevin O'Holleran
- Cambridge Advanced Imaging Centre, University of Cambridge Cambridge CB2 3DY UK
| | - Sarah E Bohndiek
- Department of Physics, University of Cambridge Cambridge CB3 0HE UK.,Cancer Research UK Cambridge Institute, University of Cambridge Cambridge CB2 0RE UK
| | - Thomas N Snaddon
- Department of Chemistry, Indiana University Bloomington 47405 USA
| | - Steven F Lee
- Department of Chemistry, University of Cambridge Cambridge CB2 1EW UK
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34
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Arndt JR, Chaibva M, Beasley M, Karanji AK, Kondalaji SG, Khakinejad M, Sarver O, Legleiter J, Valentine SJ. Nucleation Inhibition of Huntingtin Protein (htt) by Polyproline PPII Helices: A Potential Interaction with the N-Terminal α-Helical Region of Htt. Biochemistry 2020; 59:436-449. [PMID: 31814404 PMCID: PMC7344267 DOI: 10.1021/acs.biochem.9b00689] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
Huntington's disease is a genetic neurodegenerative disorder characterized by the formation of amyloid fibrils of the huntingtin protein (htt). The 17-residue N-terminal region of htt (Nt17) has been implicated in the formation of early phase oligomeric species, which may be neurotoxic. Because tertiary interactions with a downstream (C-terminal) polyproline (polyP) region of htt may disrupt the formation of oligomers, which are precursors to fibrillar species, the effect of co-incubation of a region of htt with a 10-residue polyP peptide on oligomerization and fibrillization has been examined by atomic force microscopy. From multiple, time-course experiments, morphological changes in oligomeric species are observed for the protein/peptide mixture and compared with the protein alone. Additionally, an overall decrease in fibril formation is observed for the heterogeneous mixture. To consider potential sites of interaction between the Nt17 region and polyP, mixtures containing Nt17 and polyP peptides have been examined by ion mobility spectrometry and gas-phase hydrogen-deuterium exchange coupled with mass spectrometry. These data combined with molecular dynamics simulations suggest that the C-terminal region of Nt17 may be a primary point of contact. One interpretation of the results is that polyP may possibly regulate Nt17 by inducing a random coil region in the C-terminal portion of Nt17, thus decreasing the propensity to form the reactive amphipathic α-helix. A separate interpretation is that the residues important for helix-helix interactions are blocked by polyP association.
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Affiliation(s)
- James R Arndt
- C. Eugene Bennett Department of Chemistry, West Virginia University, 100 Prospect Street, Morgantown, West Virginia 26506, United States
| | - Maxmore Chaibva
- C. Eugene Bennett Department of Chemistry, West Virginia University, 100 Prospect Street, Morgantown, West Virginia 26506, United States
| | - Maryssa Beasley
- C. Eugene Bennett Department of Chemistry, West Virginia University, 100 Prospect Street, Morgantown, West Virginia 26506, United States
| | - Ahmad Kiani Karanji
- C. Eugene Bennett Department of Chemistry, West Virginia University, 100 Prospect Street, Morgantown, West Virginia 26506, United States
| | - Samaneh Ghassabi Kondalaji
- C. Eugene Bennett Department of Chemistry, West Virginia University, 100 Prospect Street, Morgantown, West Virginia 26506, United States
| | - Mahdiar Khakinejad
- C. Eugene Bennett Department of Chemistry, West Virginia University, 100 Prospect Street, Morgantown, West Virginia 26506, United States
| | - Olivia Sarver
- C. Eugene Bennett Department of Chemistry, West Virginia University, 100 Prospect Street, Morgantown, West Virginia 26506, United States
| | - Justin Legleiter
- C. Eugene Bennett Department of Chemistry, West Virginia University, 100 Prospect Street, Morgantown, West Virginia 26506, United States
- WV Nano Safe Iniative, West Virginia University, Morgantown, West Virginia 26506, United States
- The Center for Neuroscience, West Virginia University, Morgantown, West Virginia 26506, United States
| | - Stephen J Valentine
- C. Eugene Bennett Department of Chemistry, West Virginia University, 100 Prospect Street, Morgantown, West Virginia 26506, United States
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35
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Maji D, Lu J, Sarder P, Schmieder AH, Cui G, Yang X, Pan D, Lew MD, Achilefu S, Lanza GM. Cellular Trafficking of Sn-2 Phosphatidylcholine Prodrugs Studied with Fluorescence Lifetime Imaging and Super-resolution Microscopy. PRECISION NANOMEDICINE 2018; 1:128-145. [PMID: 31249994 PMCID: PMC6597004 DOI: 10.33218/prnano1(2).180724.1] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
While the in vivo efficacy of Sn-2 phosphatidylcholine prodrugs incorporated into targeted, non-pegylated lipid-encapsulated nanoparticles was demonstrated in prior preclinical studies, the microscopic details of cell prodrug internalization and trafficking events are unknown. Classic fluorescence microscopy, fluorescence lifetime imaging microscopy, and single-molecule super-resolution microscopy were used to investigate the cellular handling of doxorubicin-prodrug and AlexaFluor™-488-prodrug. Sn-2 phosphatidylcholine prodrugs delivered by hemifusion of nanoparticle and cell phospholipid membranes functioned as phosphatidylcholine mimics, circumventing the challenges of endosome sequestration and release. Phosphatidylcholine prodrugs in the outer cell membrane leaflet translocated to the inner membrane leaflet by ATP-dependent and ATP-independent mechanisms and distributed broadly within the cytosolic membranes over the next 12 h. A portion of the phosphatidylcholine prodrug populated vesicle membranes trafficked to the perinuclear Golgi/ER region, where the drug was enzymatically liberated and activated. Native doxorubicin entered the cells, passed rapidly to the nucleus, and bound to dsDNA, whereas DOX was first enzymatically liberated from DOX-prodrug within the cytosol, particularly in the perinuclear region, before binding nuclear dsDNA. Much of DOX-prodrug was initially retained within intracellular membranes. In vitro anti-proliferation effectiveness of the two drug delivery approaches was equivalent at 48 h, suggesting that residual intracellular DOX-prodrug may constitute a slow-release drug reservoir that enhances effectiveness. We have demonstrated that Sn-2 phosphatidylcholine prodrugs function as phosphatidylcholine mimics following reported pathways of phosphatidylcholine distribution and metabolism. Drug complexed to the Sn-2 fatty acid is enzymatically liberated and reactivated over many hours, which may enhance efficacy overtime.
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Affiliation(s)
- Dolonchampa Maji
- Optical Radiology Lab, Department of Radiology, Washington University School of Medicine, St. Louis, MO 63110, USA.,Department of Biomedical Engineering, Washington University in St. Louis, MO 63130, USA
| | - Jin Lu
- Department of Electrical and Systems Engineering, Washington University in St. Louis, St. Louis, MO 63130, USA
| | - Pinaki Sarder
- Department of Pathology and Anatomical Sciences, Jacobs School of Medicine & Biomedical Sciences, University of Buffalo, Buffalo, NY 14203
| | - Anne H Schmieder
- Division of Cardiology, Department of Medicine, Washington University School of Medicine, St. Louis, MO, USA
| | - Grace Cui
- Division of Cardiology, Department of Medicine, Washington University School of Medicine, St. Louis, MO, USA
| | - Xiaoxia Yang
- Division of Cardiology, Department of Medicine, Washington University School of Medicine, St. Louis, MO, USA
| | - Dipanjan Pan
- Department of Bioengineering, University of Illinois at Urbana-Champaign, Champaign, IL, USA
| | - Matthew D Lew
- Department of Electrical and Systems Engineering, Washington University in St. Louis, St. Louis, MO 63130, USA
| | - Samuel Achilefu
- Optical Radiology Lab, Department of Radiology, Washington University School of Medicine, St. Louis, MO 63110, USA.,Department of Biomedical Engineering, Washington University in St. Louis, MO 63130, USA
| | - Gregory M Lanza
- Department of Biomedical Engineering, Washington University in St. Louis, MO 63130, USA.,Division of Cardiology, Department of Medicine, Washington University School of Medicine, St. Louis, MO, USA
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