1
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Clayton NS, Hodge RG, Infante E, Alibhai D, Zhou F, Ridley AJ. RhoU forms homo-oligomers to regulate cellular responses. J Cell Sci 2024; 137:jcs261645. [PMID: 38180080 PMCID: PMC10917059 DOI: 10.1242/jcs.261645] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2023] [Accepted: 12/21/2023] [Indexed: 01/06/2024] Open
Abstract
RhoU is an atypical member of the Rho family of small G-proteins, which has N- and C-terminal extensions compared to the classic Rho GTPases RhoA, Rac1 and Cdc42, and associates with membranes through C-terminal palmitoylation rather than prenylation. RhoU mRNA expression is upregulated in prostate cancer and is considered a marker for disease progression. Here, we show that RhoU overexpression in prostate cancer cells increases cell migration and invasion. To identify RhoU targets that contribute to its function, we found that RhoU homodimerizes in cells. We map the region involved in this interaction to the C-terminal extension and show that C-terminal palmitoylation is required for self-association. Expression of the isolated C-terminal extension reduces RhoU-induced activation of p21-activated kinases (PAKs), which are known downstream targets for RhoU, and induces cell morphological changes consistent with inhibiting RhoU function. Our results show for the first time that the activity of a Rho family member is stimulated by self-association, and this is important for its activity.
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Affiliation(s)
- Natasha S. Clayton
- School of Cellular and Molecular Medicine, University of Bristol, Biomedical Sciences Building, University Walk, Bristol BS8 1TD, UK
| | - Richard G. Hodge
- Randall Centre for Cell and Molecular Biophysics, King's College London, Guy's Campus, London SE1 1UL, UK
| | - Elvira Infante
- Randall Centre for Cell and Molecular Biophysics, King's College London, Guy's Campus, London SE1 1UL, UK
| | - Dominic Alibhai
- Wolfson Bioimaging Facility, University of Bristol, Biomedical Sciences Building, University Walk, Bristol BS8 1TD, UK
| | - Felix Zhou
- Ludwig Institute for Cancer Research, Nuffield Department of Clinical Medicine, University of Oxford, Oxford OX3 7DQ, UK
- Lyda Hill Department of Bioinformatics, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA
| | - Anne J. Ridley
- School of Cellular and Molecular Medicine, University of Bristol, Biomedical Sciences Building, University Walk, Bristol BS8 1TD, UK
- Randall Centre for Cell and Molecular Biophysics, King's College London, Guy's Campus, London SE1 1UL, UK
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2
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Zhao X, Alibhai D, Walsh TG, Tarassova N, Englert M, Birol SZ, Li Y, Williams CM, Neal CR, Burkard P, Cross SJ, Aitken EW, Waller AK, Beltrán JB, Gunning PW, Hardeman EC, Agbani EO, Nieswandt B, Hers I, Ghevaert C, Poole AW. Highly efficient platelet generation in lung vasculature reproduced by microfluidics. Nat Commun 2023; 14:4026. [PMID: 37419900 PMCID: PMC10329040 DOI: 10.1038/s41467-023-39598-9] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2022] [Accepted: 06/20/2023] [Indexed: 07/09/2023] Open
Abstract
Platelets, small hemostatic blood cells, are derived from megakaryocytes. Both bone marrow and lung are principal sites of thrombopoiesis although underlying mechanisms remain unclear. Outside the body, however, our ability to generate large number of functional platelets is poor. Here we show that perfusion of megakaryocytes ex vivo through the mouse lung vasculature generates substantial platelet numbers, up to 3000 per megakaryocyte. Despite their large size, megakaryocytes are able repeatedly to passage through the lung vasculature, leading to enucleation and subsequent platelet generation intravascularly. Using ex vivo lung and an in vitro microfluidic chamber we determine how oxygenation, ventilation, healthy pulmonary endothelium and the microvascular structure support thrombopoiesis. We also show a critical role for the actin regulator Tropomyosin 4 in the final steps of platelet formation in lung vasculature. This work reveals the mechanisms of thrombopoiesis in lung vasculature and informs approaches to large-scale generation of platelets.
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Affiliation(s)
- Xiaojuan Zhao
- School of Physiology, Pharmacology and Neuroscience, Biomedical Sciences Building, University of Bristol, Bristol, BS8 1TD, UK.
| | - Dominic Alibhai
- Wolfson BioimagingFacility, Biomedical Sciences Building, University of Bristol, Bristol, BS8 1TD, UK
| | - Tony G Walsh
- School of Physiology, Pharmacology and Neuroscience, Biomedical Sciences Building, University of Bristol, Bristol, BS8 1TD, UK
| | - Nathalie Tarassova
- School of Physiology, Pharmacology and Neuroscience, Biomedical Sciences Building, University of Bristol, Bristol, BS8 1TD, UK
| | - Maximilian Englert
- University Hospital and Rudolf Virchow Center, University of Würzburg, Würzburg, D-97080, Germany
| | - Semra Z Birol
- School of Physiology, Pharmacology and Neuroscience, Biomedical Sciences Building, University of Bristol, Bristol, BS8 1TD, UK
| | - Yong Li
- School of Physiology, Pharmacology and Neuroscience, Biomedical Sciences Building, University of Bristol, Bristol, BS8 1TD, UK
| | - Christopher M Williams
- School of Physiology, Pharmacology and Neuroscience, Biomedical Sciences Building, University of Bristol, Bristol, BS8 1TD, UK
| | - Chris R Neal
- Wolfson BioimagingFacility, Biomedical Sciences Building, University of Bristol, Bristol, BS8 1TD, UK
| | - Philipp Burkard
- University Hospital and Rudolf Virchow Center, University of Würzburg, Würzburg, D-97080, Germany
| | - Stephen J Cross
- Wolfson BioimagingFacility, Biomedical Sciences Building, University of Bristol, Bristol, BS8 1TD, UK
| | - Elizabeth W Aitken
- School of Physiology, Pharmacology and Neuroscience, Biomedical Sciences Building, University of Bristol, Bristol, BS8 1TD, UK
| | - Amie K Waller
- University of Cambridge / NHS Blood and Transplant, Wellcome-MRC Cambridge Stem Cell Institute, Jeffrey Cheah Biomedical Centre, Cambridge Biomedical Campus, University of Cambridge, Cambridge, CB2 0AW, UK
| | - José Ballester Beltrán
- University of Cambridge / NHS Blood and Transplant, Wellcome-MRC Cambridge Stem Cell Institute, Jeffrey Cheah Biomedical Centre, Cambridge Biomedical Campus, University of Cambridge, Cambridge, CB2 0AW, UK
| | - Peter W Gunning
- School of Medical Sciences, University of New South Wales, Sydney, NSW, 2052, Australia
| | - Edna C Hardeman
- School of Medical Sciences, University of New South Wales, Sydney, NSW, 2052, Australia
| | - Ejaife O Agbani
- Cumming School of Medicine, University of Calgary, Calgary, AB, T2N 1N4, Canada
| | - Bernhard Nieswandt
- University Hospital and Rudolf Virchow Center, University of Würzburg, Würzburg, D-97080, Germany
| | - Ingeborg Hers
- School of Physiology, Pharmacology and Neuroscience, Biomedical Sciences Building, University of Bristol, Bristol, BS8 1TD, UK
| | - Cedric Ghevaert
- University of Cambridge / NHS Blood and Transplant, Wellcome-MRC Cambridge Stem Cell Institute, Jeffrey Cheah Biomedical Centre, Cambridge Biomedical Campus, University of Cambridge, Cambridge, CB2 0AW, UK
| | - Alastair W Poole
- School of Physiology, Pharmacology and Neuroscience, Biomedical Sciences Building, University of Bristol, Bristol, BS8 1TD, UK.
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3
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Johnson PA, Menegatti S, Chambers AC, Alibhai D, Collard TJ, Williams AC, Bayley H, Perriman AW. A rapid high throughput bioprinted colorectal cancer spheroid platform for in vitrodrug- and radiation-response. Biofabrication 2022; 15:014103. [PMID: 36321254 DOI: 10.1088/1758-5090/ac999f] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2022] [Accepted: 10/12/2022] [Indexed: 11/07/2022]
Abstract
We describe the development of a high-throughput bioprinted colorectal cancer (CRC) spheroid platform with high levels of automation, information content, and low cell number requirement. This is achieved via the formulation of a hydrogel bioink with a compressive Young's modulus that is commensurate with that of colonic tissue (1-3 kPa), which supports exponential growth of spheroids from a wide range of CRC cell lines. The resulting spheroids display tight cell-cell junctions, bioink matrix-cell interactions and necrotic hypoxic cores. By combining high content light microscopy imaging and processing with rapid multiwell plate bioprinting, dose-response profiles are generated from CRC spheroids challenged with oxaliplatin (OX) and fluorouracil (5FU), as well as radiotherapy. Bioprinted CRC spheroids are shown to exhibit high levels of chemoresistance relative to cell monolayers, and OX was found to be significantly less effective against tumour spheroids than in monolayer culture, when compared to 5FU.
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Affiliation(s)
- Peter A Johnson
- Department of Chemistry, University of Oxford, Oxford OX1 3TA, United Kingdom
| | - Sara Menegatti
- School of Cellular and Molecular Medicine, University of Bristol, Bristol BS8 1TD, United Kingdom
| | - Adam C Chambers
- School of Cellular and Molecular Medicine, University of Bristol, Bristol BS8 1TD, United Kingdom
| | - Dominic Alibhai
- Wolfson Bioimaging Facility, University of Bristol, Bristol BS8 1TD, United Kingdom
| | - Tracey J Collard
- School of Cellular and Molecular Medicine, University of Bristol, Bristol BS8 1TD, United Kingdom
| | - Ann C Williams
- School of Cellular and Molecular Medicine, University of Bristol, Bristol BS8 1TD, United Kingdom
| | - Hagan Bayley
- Department of Chemistry, University of Oxford, Oxford OX1 3TA, United Kingdom
| | - Adam W Perriman
- School of Cellular and Molecular Medicine, University of Bristol, Bristol BS8 1TD, United Kingdom
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4
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Stan GF, Shoemark DK, Alibhai D, Hanley JG. Ca2+ Regulates Dimerization of the BAR Domain Protein PICK1 and Consequent Membrane Curvature. Front Mol Neurosci 2022; 15:893739. [PMID: 35721319 PMCID: PMC9201945 DOI: 10.3389/fnmol.2022.893739] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2022] [Accepted: 05/04/2022] [Indexed: 11/13/2022] Open
Abstract
Bin-Amphiphysin-Rvs (BAR) domain proteins are critical regulators of membrane geometry. They induce and stabilize membrane curvature for processes, such as clathrin-coated pit formation and endosomal membrane tubulation. BAR domains form their characteristic crescent-shaped structure in the dimeric form, indicating that the formation of the dimer is critical to their function of inducing membrane curvature and suggesting that a dynamic monomer–dimer equilibrium regulated by cellular signaling would be a powerful mechanism for controlling BAR domain protein function. However, to the best of our knowledge, cellular mechanisms for regulating BAR domain dimerization remain unexplored. PICK1 is a Ca2+-binding BAR domain protein involved in the endocytosis and endosomal recycling of neuronal AMPA receptors and other transmembrane proteins. In this study, we demonstrated that PICK1 dimerization is regulated by a direct effect of Ca2+ ions via acidic regions in the BAR domain and at the N-terminus. While the cellular membrane tubulating activity of PICK1 is absent under basal conditions, Ca2+ influx causes the generation of membrane tubules that originate from the cell surface. Furthermore, in neurons, PICK1 dimerization increases transiently following NMDA receptor stimulation. We believe that this novel mechanism for regulating BAR domain dimerization and function represents a significant conceptual advance in our knowledge about the regulation of cellular membrane curvature.
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Affiliation(s)
- Georgiana F. Stan
- School of Biochemistry, University of Bristol, Bristol, United Kingdom
| | | | - Dominic Alibhai
- Wolfson Bioimaging Facility, University of Bristol, Bristol, United Kingdom
| | - Jonathan G. Hanley
- School of Biochemistry, University of Bristol, Bristol, United Kingdom
- *Correspondence: Jonathan G. Hanley,
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5
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Zhao X, Alibhai D, Sun T, Khalil J, Hutchinson JL, Olzak K, Williams CM, Li Y, Sessions R, Cross S, Seager R, Aungraheeta R, Leard A, McKinnon CM, Phillips D, Zhang L, Poole AW, Banting G, Mundell SJ. Tetherin/BST2, a physiologically and therapeutically relevant regulator of platelet receptor signalling. Blood Adv 2021; 5:1884-1898. [PMID: 33792632 PMCID: PMC8045503 DOI: 10.1182/bloodadvances.2020003182] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2020] [Accepted: 01/20/2021] [Indexed: 11/20/2022] Open
Abstract
The reactivity of platelets, which play a key role in the pathogenesis of atherothrombosis, is tightly regulated. The integral membrane protein tetherin/bone marrow stromal antigen-2 (BST-2) regulates membrane organization, altering both lipid and protein distribution within the plasma membrane. Because membrane microdomains have an established role in platelet receptor biology, we sought to characterize the physiological relevance of tetherin/BST-2 in those cells. To characterize the potential importance of tetherin/BST-2 to platelet function, we used tetherin/BST-2-/- murine platelets. In the mice, we found enhanced function and signaling downstream of a subset of membrane microdomain-expressing receptors, including the P2Y12, TP thromboxane, thrombin, and GPVI receptors. Preliminary studies in humans have revealed that treatment with interferon-α (IFN-α), which upregulates platelet tetherin/BST-2 expression, also reduces adenosine diphosphate-stimulated platelet receptor function and reactivity. A more comprehensive understanding of how tetherin/BST-2 negatively regulates receptor function was provided in cell line experiments, where we focused on the therapeutically relevant P2Y12 receptor (P2Y12R). Tetherin/BST-2 expression reduced both P2Y12R activation and trafficking, which was accompanied by reduced receptor lateral mobility specifically within membrane microdomains. In fluorescence lifetime imaging-Förster resonance energy transfer (FLIM-FRET)-based experiments, agonist stimulation reduced basal association between P2Y12R and tetherin/BST-2. Notably, the glycosylphosphatidylinositol (GPI) anchor of tetherin/BST-2 was required for both receptor interaction and observed functional effects. In summary, we established, for the first time, a fundamental role of the ubiquitously expressed protein tetherin/BST-2 in negatively regulating membrane microdomain-expressed platelet receptor function.
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Affiliation(s)
- Xiaojuan Zhao
- School of Physiology, Pharmacology, and Neuroscience, and
| | - Dominic Alibhai
- Wolfson Bioimaging Facility, University of Bristol, Bristol, United Kingdom
| | - Ting Sun
- State Key Laboratory of Experimental Hematology, Key Laboratory of Gene Therapy for Blood Disease, Institute of Hematology and Blood Disease Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Tianjin, China; and
| | - Jawad Khalil
- School of Physiology, Pharmacology, and Neuroscience, and
| | | | - Kaya Olzak
- School of Physiology, Pharmacology, and Neuroscience, and
| | | | - Yong Li
- School of Physiology, Pharmacology, and Neuroscience, and
| | - Richard Sessions
- School of Biochemistry, University of Bristol, Bristol, United Kingdom
| | - Stephen Cross
- Wolfson Bioimaging Facility, University of Bristol, Bristol, United Kingdom
| | - Richard Seager
- School of Physiology, Pharmacology, and Neuroscience, and
| | | | - Alan Leard
- Wolfson Bioimaging Facility, University of Bristol, Bristol, United Kingdom
| | | | - David Phillips
- School of Physiology, Pharmacology, and Neuroscience, and
| | - Lei Zhang
- State Key Laboratory of Experimental Hematology, Key Laboratory of Gene Therapy for Blood Disease, Institute of Hematology and Blood Disease Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Tianjin, China; and
| | | | - George Banting
- School of Biochemistry, University of Bristol, Bristol, United Kingdom
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6
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Tian J, Zhang Y, Du L, He Y, Jin XH, Pearce S, Eloi JC, Harniman RL, Alibhai D, Ye R, Phillips DL, Manners I. Tailored self-assembled photocatalytic nanofibres for visible-light-driven hydrogen production. Nat Chem 2020; 12:1150-1156. [PMID: 33219362 DOI: 10.1038/s41557-020-00580-3] [Citation(s) in RCA: 55] [Impact Index Per Article: 13.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2020] [Accepted: 10/14/2020] [Indexed: 12/12/2022]
Abstract
The creation of efficient artificial systems that mimic natural photosynthesis represents a key current challenge. Here, we describe a high-performance recyclable photocatalytic core-shell nanofibre system that integrates a cobalt catalyst and a photosensitizer in close proximity for hydrogen production from water using visible light. The composition, microstructure and dimensions-and thereby the catalytic activity-of the nanofibres were controlled through living crystallization-driven self-assembly. In this seeded growth strategy, block copolymers with crystallizable core-forming blocks and functional coronal segments were coassembled into low-dispersity, one-dimensional architectures. Under optimized conditions, the nanofibres promote the photocatalytic production of hydrogen from water with an overall quantum yield for solar energy conversion to hydrogen gas of ~4.0% (with a turnover number of >7,000 over 5 h, a frequency of >1,400 h-1 and a H2 production rate of >0.327 μmol h-1 with 1.34 μg of catalytic polymer (that is, >244,300 μmol h-1 g-1 of catalytic polymer)).
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Affiliation(s)
- Jia Tian
- School of Chemistry, University of Bristol, Bristol, UK.,Department of Chemistry, University of Victoria, Victoria, British Columbia, Canada
| | - Yifan Zhang
- School of Chemistry, University of Bristol, Bristol, UK.,Department of Chemistry, University of Victoria, Victoria, British Columbia, Canada
| | - Lili Du
- Department of Chemistry, The University of Hong Kong, Hong Kong, China
| | - Yunxiang He
- School of Chemistry, University of Bristol, Bristol, UK
| | - Xu-Hui Jin
- School of Chemistry, University of Bristol, Bristol, UK
| | - Samuel Pearce
- School of Chemistry, University of Bristol, Bristol, UK
| | | | | | - Dominic Alibhai
- Wolfson Bioimaging Facility, University of Bristol, Bristol, UK
| | - Ruquan Ye
- Department of Chemistry, State Key Laboratory of Marine Pollution, City University of Hong Kong, Hong Kong, China
| | | | - Ian Manners
- School of Chemistry, University of Bristol, Bristol, UK. .,Department of Chemistry, University of Victoria, Victoria, British Columbia, Canada.
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7
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Tan SL, Alibhai D, Cross SJ, Thompson H, Wülfing C. Super-resolution Imaging of the T cell Central Supramolecular Signaling Cluster Using Stimulated Emission Depletion Microscopy. Bio Protoc 2020; 10:e3806. [PMID: 33659460 PMCID: PMC7842649 DOI: 10.21769/bioprotoc.3806] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2020] [Revised: 08/23/2020] [Accepted: 09/22/2020] [Indexed: 12/15/2022] Open
Abstract
Supramolecular signaling assemblies are of interest for their unique signaling properties. A µm scale signaling assembly, the central supramolecular signaling cluster (cSMAC), forms at the center interface of T cells activated by antigen presenting cells (APC). The adaptor protein linker for activation of T cells (LAT) is a key cSMAC component. The cSMAC has widely been studied using total internal reflection fluorescence microscopy of CD4+ T cells activated by planar APC substitutes. Here we provide a protocol to image the cSMAC in its cellular context at the interface between a T cell and an APC. Super resolution stimulated emission depletion microscopy (STED) was utilized to determine the localization of LAT, that of its active, phosphorylated form and its entire pool. Agonist peptide-loaded APCs were incubated with TCR transgenic CD4+ T cells for 4.5 min before fixation and antibody staining. Fixed cell couples were imaged using a 100x 1.4 NA objective on a Leica SP8 AOBS confocal laser scanning microscope. LAT clustered in multiple supramolecular complexes and their number and size distributions were determined. Using this protocol, cSMAC properties in its cellular context at the interface between a T cell and an APC could be quantified.
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Affiliation(s)
- Sin Lih Tan
- School of Cellular and Molecular Medicine, University of Bristol, Bristol, United Kingdom,*For correspondence: ;
| | - Dominic Alibhai
- Wolfson BioImaging Facility, University of Bristol, Bristol, United Kingdom
| | - Stephen J. Cross
- Wolfson BioImaging Facility, University of Bristol, Bristol, United Kingdom
| | - Harry Thompson
- School of Biochemistry, University of Bristol, Bristol, United Kingdom
| | - Christoph Wülfing
- School of Cellular and Molecular Medicine, University of Bristol, Bristol, United Kingdom,*For correspondence: ;
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8
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Clark DJ, McMillan LE, Tan SL, Bellomo G, Massoue C, Thompson H, Mykhaylechko L, Alibhai D, Ruan X, Singleton KL, Du M, Hedges A, Schwartzberg PL, Verkade P, Murphy RF, Wülfing C. Transient protein accumulation at the center of the T cell antigen-presenting cell interface drives efficient IL-2 secretion. eLife 2019; 8:45789. [PMID: 31663508 PMCID: PMC6821493 DOI: 10.7554/elife.45789] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2019] [Accepted: 09/25/2019] [Indexed: 01/06/2023] Open
Abstract
Supramolecular signaling assemblies are of interest for their unique signaling properties. A µm scale signaling assembly, the central supramolecular signaling cluster (cSMAC), forms at the center of the interface of T cells activated by antigen-presenting cells. We have determined that it is composed of multiple complexes of a supramolecular volume of up to 0.5 µm3 and associated with extensive membrane undulations. To determine cSMAC function, we have systematically manipulated the localization of three adaptor proteins, LAT, SLP-76, and Grb2. cSMAC localization varied between the adaptors and was diminished upon blockade of the costimulatory receptor CD28 and deficiency of the signal amplifying kinase Itk. Reconstitution of cSMAC localization restored IL-2 secretion which is a key T cell effector function as dependent on reconstitution dynamics. Our data suggest that the cSMAC enhances early signaling by facilitating signaling interactions and attenuates signaling thereafter through sequestration of a more limited set of signaling intermediates. Cells receive dozens of signals at different times and in different places. Integrating incoming information and deciding how to respond is no easy task. Signaling molecules on the cell surface pass messages inwards using chemical messengers that interact in complicated networks within the cell. One way to unravel the complexity of these networks is to look at specific groups of signaling molecules in test tubes to see how they interact. But the interior of a living cell is a very different environment. Molecules inside cells are tightly packed and, under certain conditions, they interact with each other by the thousands. They form structures known as ‘supramolecular complexes’, which changes their behavior. One such supramolecular complex is the ‘central supramolecular activation cluster’, or cSMAC for short. It forms under the surface of immune cells called T cells when they are getting ready to fight an infection. Under the microscope, the cSMAC looks like the bullseye of a dartboard, forming a crowd of signaling molecules at the center of the interface between the T cell and another cell. Its exact role is not clear, but evidence suggests it helps to start and stop the signals that switch T cells on. The cSMAC contains two key protein adaptors called LAT and SLP-76 that help to hold the structure together. So, to find out what the cSMAC does, Clark et al. genetically modified these adaptors to gain control over when the cSMAC forms. Clark et al. examined mouse T cells using super-resolution microscopy and electron microscopy, watching as other immune cells delivered the signal to switch on. As the T cells started to activate, the composition of the cSMAC changed. In the first two minutes after the cells started activating, the cSMAC included a large number of different components. This made T cell activation more efficient, possibly because the supramolecular complex was helping the network of signals to interact. Later, the cSMAC started to lose many of these components. Separating components may have helped to stop the activation signals. Understanding how T cells activate could lead to the possibility of turning them on or off in immune-related diseases. But these findings are not just relevant to immune cells. Other cells also use supramolecular complexes to control their signaling. Investigating how these complexes change over time could help us to understand how other cell types make decisions.
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Affiliation(s)
- Danielle J Clark
- School of Cellular and Molecular Medicine, University of Bristol, Bristol, United Kingdom
| | - Laura E McMillan
- School of Cellular and Molecular Medicine, University of Bristol, Bristol, United Kingdom
| | - Sin Lih Tan
- School of Cellular and Molecular Medicine, University of Bristol, Bristol, United Kingdom
| | - Gaia Bellomo
- School of Cellular and Molecular Medicine, University of Bristol, Bristol, United Kingdom
| | - Clementine Massoue
- School of Cellular and Molecular Medicine, University of Bristol, Bristol, United Kingdom
| | - Harry Thompson
- School of Cellular and Molecular Medicine, University of Bristol, Bristol, United Kingdom
| | - Lidiya Mykhaylechko
- School of Cellular and Molecular Medicine, University of Bristol, Bristol, United Kingdom
| | - Dominic Alibhai
- School of Biochemistry, University of Bristol, Bristol, United Kingdom
| | - Xiongtao Ruan
- Computational Biology Department, School of Computer Science, Carnegie Mellon University, Pittsburgh, United States
| | - Kentner L Singleton
- Department of Immunology, University of Texas Southwestern Medical Center, Dallas, United States
| | - Minna Du
- Department of Immunology, University of Texas Southwestern Medical Center, Dallas, United States
| | - Alan Hedges
- School of Cellular and Molecular Medicine, University of Bristol, Bristol, United Kingdom
| | - Pamela L Schwartzberg
- Genetic Disease Research Branch, National Human Genome Research Institute, National Institutes of Health, Bethesda, United States
| | - Paul Verkade
- School of Biochemistry, University of Bristol, Bristol, United Kingdom
| | - Robert F Murphy
- Computational Biology Department, School of Computer Science, Carnegie Mellon University, Pittsburgh, United States.,Department of Biological Sciences, Carnegie Mellon University, Pittsburgh, United States.,Department of Biomedical Engineering, Carnegie Mellon University, Pittsburgh, United States.,Department of Machine Learning, Carnegie Mellon University, Pittsburgh, United States.,Freiburg Institute for Advanced Studies, Albert Ludwig University of Freiburg, Freiburg, Germany.,Faculty of Biology, Albert Ludwig University of Freiburg, Freiburg, Germany
| | - Christoph Wülfing
- School of Cellular and Molecular Medicine, University of Bristol, Bristol, United Kingdom.,Department of Immunology, University of Texas Southwestern Medical Center, Dallas, United States
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9
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Walas D, Nowicki-Osuch K, Alibhai D, von Linstow Roloff E, Coghill J, Waterfall C, Paton JF. Inflammatory pathways are central to posterior cerebrovascular artery remodelling prior to the onset of congenital hypertension. J Cereb Blood Flow Metab 2019; 39:1803-1817. [PMID: 29651914 PMCID: PMC6724458 DOI: 10.1177/0271678x18769180] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
Cerebral artery hypoperfusion may provide the basis for linking ischemic stroke with hypertension. Brain hypoperfusion may induce hypertension that may serve as an auto-protective mechanism to prevent ischemic stroke. We hypothesised that hypertension is caused by remodelling of the cerebral arteries, which is triggered by inflammation. We used a congenital rat model of hypertension and examined age-related changes in gene expression of the cerebral arteries using RNA sequencing. Prior to hypertension, we found changes in signalling pathways associated with the immune system and fibrosis. Validation studies using second harmonics generation microscopy revealed upregulation of collagen type I and IV in both tunica externa and media. These changes in the extracellular matrix of cerebral arteries pre-empted hypertension accounting for their increased stiffness and resistance, both potentially conducive to stroke. These data indicate that inflammatory driven cerebral artery remodelling occurs prior to the onset of hypertension and may be a trigger elevating systemic blood pressure in genetically programmed hypertension.
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Affiliation(s)
- Dawid Walas
- 1 School of Physiology, Pharmacology and Neuroscience, Biomedical Sciences, University of Bristol, Bristol, UK
| | | | - Dominic Alibhai
- 3 Wolfson Bioimaging Facility, School of Biochemistry, Biomedical Sciences, University of Bristol, Bristol, UK
| | - Eva von Linstow Roloff
- 1 School of Physiology, Pharmacology and Neuroscience, Biomedical Sciences, University of Bristol, Bristol, UK
| | - Jane Coghill
- 4 Genomics Facility, School of Biological Sciences, Bristol, UK
| | | | - Julian Fr Paton
- 1 School of Physiology, Pharmacology and Neuroscience, Biomedical Sciences, University of Bristol, Bristol, UK.,5 Department of Physiology, Faculty of Medical and Health Sciences, University of Auckland, Grafton, New Zealand
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10
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Gulácsy CE, Meade R, Catici DAM, Soeller C, Pantos GD, Jones DD, Alibhai D, Jepson M, Valev VK, Mason JM, Williams RJ, Pudney CR. Excitation-Energy-Dependent Molecular Beacon Detects Early Stage Neurotoxic Aβ Aggregates in the Presence of Cortical Neurons. ACS Chem Neurosci 2019; 10:1240-1250. [PMID: 30346718 DOI: 10.1021/acschemneuro.8b00322] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
There is now crucial medical importance placed on understanding the role of early stage, subvisible protein aggregation, particularly in neurodegenerative disease. While there are strategies for detecting such aggregates in vitro, there is no approach at present that can detect these toxic species associated with cells and specific subcellular compartments. We have exploited excitation-energy-dependent fluorescence edge-shift of recombinant protein labeled with a molecular beacon, to provide a sensitive read out for the presence of subvisible protein aggregates. To demonstrate the potential utility of the approach, we examine the major peptide associated with the initiation of Alzheimer's disease, amyloid β-protein (Aβ) at a patho-physiologically relevant concentration in mouse cortical neurons. Using our approach, we find preliminary evidence that subvisible Aβ aggregates are detected at specific subcellular regions and that neurons drive the formation of specific Aβ aggregate conformations. These findings therefore demonstrate the potential of a novel fluorescence-based approach for detecting and imaging protein aggregates in a cellular context, which can be used to sensitively probe the association of early stage toxic protein aggregates within subcellular compartments.
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Affiliation(s)
| | | | | | - Christian Soeller
- Biomedical Physics, University of Exeter, Exeter EX4 4QD, United Kingdom
| | | | - D. Dafydd Jones
- School of Biosciences, Cardiff University, Cardiff CF10 3TL, United Kingdom
| | - Dominic Alibhai
- Wolfson Bioimaging Facility, University of Bristol, Bristol BS8 1TS, United Kingdom
| | - Mark Jepson
- Wolfson Bioimaging Facility, University of Bristol, Bristol BS8 1TS, United Kingdom
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11
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Sherrard A, Bishop P, Panagi M, Villagomez MB, Alibhai D, Kaidi A. Streamlined histone-based fluorescence lifetime imaging microscopy (FLIM) for studying chromatin organisation. Biol Open 2018; 7:bio031476. [PMID: 29535103 PMCID: PMC5898265 DOI: 10.1242/bio.031476] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2017] [Accepted: 03/05/2018] [Indexed: 01/18/2023] Open
Abstract
Changes in chromatin structure are key determinants of genomic responses. Thus, methods that enable such measurements are instrumental for investigating genome regulation and function. Here, we report further developments and validation of a streamlined method of histone-based fluorescence lifetime imaging microscopy (FLIM) that robustly detects chromatin compaction states in fixed and live cells, in 2D and 3D. We present a quality-controlled and detailed method that is simpler and faster than previous methods, and uses FLIMfit open-source software. We demonstrate the versatility of this chromatin FLIM through its combination with immunofluorescence and implementation in immortalised and primary cells. We applied this method to investigate the regulation of chromatin organisation after genotoxic stress and provide new insights into the role of ATM in controlling chromatin structure independently of DNA damage. Collectively, we present an adaptable chromatin FLIM method for examining chromatin structure and establish its utility in mammalian cells.
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Affiliation(s)
- Alice Sherrard
- Nuclear Dynamics Laboratory, School of Cellular and Molecular Medicine, Biomedical Sciences Building, University of Bristol, Bristol, BS8 1TD, UK
| | - Paul Bishop
- Nuclear Dynamics Laboratory, School of Cellular and Molecular Medicine, Biomedical Sciences Building, University of Bristol, Bristol, BS8 1TD, UK
| | - Melanie Panagi
- Nuclear Dynamics Laboratory, School of Cellular and Molecular Medicine, Biomedical Sciences Building, University of Bristol, Bristol, BS8 1TD, UK
| | - Maria Beatriz Villagomez
- Nuclear Dynamics Laboratory, School of Cellular and Molecular Medicine, Biomedical Sciences Building, University of Bristol, Bristol, BS8 1TD, UK
| | - Dominic Alibhai
- Wolfson Bioimaging Facility, Biomedical Sciences Building, University of Bristol, Bristol, BS8 1TD, UK
| | - Abderrahmane Kaidi
- Nuclear Dynamics Laboratory, School of Cellular and Molecular Medicine, Biomedical Sciences Building, University of Bristol, Bristol, BS8 1TD, UK
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12
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Lee MJ, Mantell J, Hodgson L, Alibhai D, Fletcher JM, Brown IR, Frank S, Xue WF, Verkade P, Woolfson DN, Warren MJ. Engineered synthetic scaffolds for organizing proteins within the bacterial cytoplasm. Nat Chem Biol 2017; 14:142-147. [DOI: 10.1038/nchembio.2535] [Citation(s) in RCA: 93] [Impact Index Per Article: 13.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2017] [Accepted: 11/01/2017] [Indexed: 12/21/2022]
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13
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Baarlink C, Plessner M, Sherrard A, Morita K, Misu S, Virant D, Kleinschnitz EM, Harniman R, Alibhai D, Baumeister S, Miyamoto K, Endesfelder U, Kaidi A, Grosse R. A transient pool of nuclear F-actin at mitotic exit controls chromatin organization. Nat Cell Biol 2017; 19:1389-1399. [PMID: 29131140 DOI: 10.1038/ncb3641] [Citation(s) in RCA: 129] [Impact Index Per Article: 18.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2017] [Accepted: 10/05/2017] [Indexed: 12/13/2022]
Abstract
Re-establishment of nuclear structure and chromatin organization after cell division is integral for genome regulation or development and is frequently altered during cancer progression. The mechanisms underlying chromatin expansion in daughter cells remain largely unclear. Here, we describe the transient formation of nuclear actin filaments (F-actin) during mitotic exit. These nuclear F-actin structures assemble in daughter cell nuclei and undergo dynamic reorganization to promote nuclear protrusions and volume expansion throughout early G1 of the cell cycle. Specific inhibition of this nuclear F-actin assembly impaired nuclear expansion and chromatin decondensation after mitosis and during early mouse embryonic development. Biochemical screening for mitotic nuclear F-actin interactors identified the actin-disassembling factor cofilin-1. Optogenetic regulation of cofilin-1 revealed its critical role for controlling timing, turnover and dynamics of F-actin assembly inside daughter cell nuclei. Our findings identify a cell-cycle-specific and spatiotemporally controlled form of nuclear F-actin that reorganizes the mammalian nucleus after mitosis.
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Affiliation(s)
- Christian Baarlink
- Institute of Pharmacology, BPC Marburg, University of Marburg, Karl-von-Frisch-Str. 1, 35043 Marburg, Germany
| | - Matthias Plessner
- Institute of Pharmacology, BPC Marburg, University of Marburg, Karl-von-Frisch-Str. 1, 35043 Marburg, Germany
| | - Alice Sherrard
- School of Cellular and Molecular Medicine, Biomedical Sciences, University of Bristol, University Walk, Bristol BS8 1TD, UK
| | - Kohtaro Morita
- Faculty of Biology-Oriented Science and Technology, Kindai University, 930 Nishimitani, Wakayama 649-6493, Japan
| | - Shinji Misu
- Faculty of Biology-Oriented Science and Technology, Kindai University, 930 Nishimitani, Wakayama 649-6493, Japan
| | - David Virant
- Department of Systems and Synthetic Microbiology, Max Planck Institute for Terrestrial Microbiology and LOEWE Center for Synthetic Microbiology (SYNMIKRO), Karl-von-Frisch-Str. 16, 35043 Marburg, Germany
| | - Eva-Maria Kleinschnitz
- Institute of Pharmacology, BPC Marburg, University of Marburg, Karl-von-Frisch-Str. 1, 35043 Marburg, Germany
| | - Robert Harniman
- Electron Microscopy Unit, School of Chemistry, Biomedical Sciences, University of Bristol, Bristol BS8 1TS, UK
| | - Dominic Alibhai
- Wolfson Bioimaging Facility, University of Bristol, Bristol BS8 1TD, UK
| | - Stefan Baumeister
- Protein Analytics, Faculty of Biology, University of Marburg, Karl-von-Frisch-Str. 8, 35043 Marburg, Germany
| | - Kei Miyamoto
- Faculty of Biology-Oriented Science and Technology, Kindai University, 930 Nishimitani, Wakayama 649-6493, Japan
| | - Ulrike Endesfelder
- Department of Systems and Synthetic Microbiology, Max Planck Institute for Terrestrial Microbiology and LOEWE Center for Synthetic Microbiology (SYNMIKRO), Karl-von-Frisch-Str. 16, 35043 Marburg, Germany
| | - Abderrahmane Kaidi
- School of Cellular and Molecular Medicine, Biomedical Sciences, University of Bristol, University Walk, Bristol BS8 1TD, UK
| | - Robert Grosse
- Institute of Pharmacology, BPC Marburg, University of Marburg, Karl-von-Frisch-Str. 1, 35043 Marburg, Germany
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14
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Ross JF, Bridges A, Fletcher JM, Shoemark D, Alibhai D, Bray HEV, Beesley JL, Dawson WM, Hodgson LR, Mantell J, Verkade P, Edge CM, Sessions RB, Tew D, Woolfson DN. Decorating Self-Assembled Peptide Cages with Proteins. ACS Nano 2017; 11:7901-7914. [PMID: 28686416 DOI: 10.1021/acsnano.7b02368] [Citation(s) in RCA: 43] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/12/2023]
Abstract
An ability to organize and encapsulate multiple active proteins into defined objects and spaces at the nanoscale has potential applications in biotechnology, nanotechnology, and synthetic biology. Previously, we have described the design, assembly, and characterization of peptide-based self-assembled cages (SAGEs). These ≈100 nm particles comprise thousands of copies of de novo designed peptide-based hubs that array into a hexagonal network and close to give caged structures. Here, we show that, when fused to the designed peptides, various natural proteins can be co-assembled into SAGE particles. We call these constructs pSAGE for protein-SAGE. These particles tolerate the incorporation of multiple copies of folded proteins fused to either the N or the C termini of the hubs, which modeling indicates form the external and internal surfaces of the particles, respectively. Up to 15% of the hubs can be functionalized without compromising the integrity of the pSAGEs. This corresponds to hundreds of copies giving mM local concentrations of protein in the particles. Moreover, and illustrating the modularity of the SAGE system, we show that multiple different proteins can be assembled simultaneously into the same particle. As the peptide-protein fusions are made via recombinant expression of synthetic genes, we envisage that pSAGE systems could be developed modularly to actively encapsulate or to present a wide variety of functional proteins, allowing them to be developed as nanoreactors through the immobilization of enzyme cascades or as vehicles for presenting whole antigenic proteins as synthetic vaccine platforms.
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Affiliation(s)
- James F Ross
- School of Chemistry, University of Bristol , Cantock's Close, Bristol BS8 1TS, United Kingdom
| | - Angela Bridges
- GlaxoSmithKline (GSK) , Gunnels Wood Rd, Stevenage SG21 2NY, United Kingdom
| | - Jordan M Fletcher
- School of Chemistry, University of Bristol , Cantock's Close, Bristol BS8 1TS, United Kingdom
| | - Deborah Shoemark
- BrisSynBio, Life Sciences Building, University of Bristol , Tyndall Avenue, Bristol BS8 1TQ, United Kingdom
| | | | - Harriet E V Bray
- School of Chemistry, University of Bristol , Cantock's Close, Bristol BS8 1TS, United Kingdom
| | - Joseph L Beesley
- School of Chemistry, University of Bristol , Cantock's Close, Bristol BS8 1TS, United Kingdom
| | - William M Dawson
- School of Chemistry, University of Bristol , Cantock's Close, Bristol BS8 1TS, United Kingdom
| | | | | | | | - Colin M Edge
- GlaxoSmithKline (GSK) , Gunnels Wood Rd, Stevenage SG21 2NY, United Kingdom
| | - Richard B Sessions
- BrisSynBio, Life Sciences Building, University of Bristol , Tyndall Avenue, Bristol BS8 1TQ, United Kingdom
| | - David Tew
- GlaxoSmithKline (GSK) , Gunnels Wood Rd, Stevenage SG21 2NY, United Kingdom
| | - Derek N Woolfson
- School of Chemistry, University of Bristol , Cantock's Close, Bristol BS8 1TS, United Kingdom
- BrisSynBio, Life Sciences Building, University of Bristol , Tyndall Avenue, Bristol BS8 1TQ, United Kingdom
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15
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Martin N, Sharma KP, Harniman RL, Richardson RM, Hutchings RJ, Alibhai D, Li M, Mann S. Light-induced dynamic shaping and self-division of multipodal polyelectrolyte-surfactant microarchitectures via azobenzene photomechanics. Sci Rep 2017; 7:41327. [PMID: 28112266 PMCID: PMC5256308 DOI: 10.1038/srep41327] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2016] [Accepted: 12/15/2016] [Indexed: 01/11/2023] Open
Abstract
Light-induced shape transformations represent a fundamental step towards the emergence of adaptive materials exhibiting photomechanical behaviours. Although a range of covalent azobenzene-based photoactive materials has been demonstrated, the use of dynamic photoisomerization in mesostructured soft solids involving non-covalent co-assembly has received little attention. Here we prepare discrete micrometre-sized hydrated particles of a hexagonally ordered polyelectrolyte-surfactant mesophase based on the electrostatically induced co-assembly of poly(sodium acrylate) (PAA) and trans-azobenzene trimethylammonium bromide (trans-azoTAB), and demonstrate unusual non-equilibrium substrate-mediated shape transformations to complex multipodal microarchitectures under continuous blue light. The microparticles spontaneously sequester molecular dyes, functional enzymes and oligonucleotides, and undergo self-division when transformed to the cis state under UV irradiation. Our results illustrate that weak bonding interactions in polyelectrolyte-azobenzene surfactant mesophases can be exploited for photo-induced long-range molecular motion, and highlight how dynamic shape transformations and autonomous division can be activated by spatially confining azobenzene photomechanics in condensed microparticulate materials.
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Affiliation(s)
- Nicolas Martin
- Centre for Organized Matter Chemistry, School of Chemistry, University of Bristol, Bristol BS8 1TS, UK
| | - Kamendra P. Sharma
- Centre for Organized Matter Chemistry, School of Chemistry, University of Bristol, Bristol BS8 1TS, UK
- Department of Chemistry, Indian Institute of Technology Bombay, Mumbai, 400076, India
| | - Robert L. Harniman
- Centre for Organized Matter Chemistry, School of Chemistry, University of Bristol, Bristol BS8 1TS, UK
| | - Robert M. Richardson
- School of Physics, H. H. Wills Physics Laboratory, University of Bristol, Tyndall Avenue, Bristol BS8 1TL, UK
| | - Ricky J. Hutchings
- Centre for Organized Matter Chemistry, School of Chemistry, University of Bristol, Bristol BS8 1TS, UK
| | - Dominic Alibhai
- Wolfson Bioimaging Facility, Faculty of Biomedical Sciences, University of Bristol, University Walk, Bristol BS8 1TD, UK
| | - Mei Li
- Centre for Organized Matter Chemistry, School of Chemistry, University of Bristol, Bristol BS8 1TS, UK
| | - Stephen Mann
- Centre for Organized Matter Chemistry, School of Chemistry, University of Bristol, Bristol BS8 1TS, UK
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16
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Görlitz F, Kelly DJ, Warren SC, Alibhai D, West L, Kumar S, Alexandrov Y, Munro I, Garcia E, McGinty J, Talbot C, Serwa RA, Thinon E, da Paola V, Murray EJ, Stuhmeier F, Neil MAA, Tate EW, Dunsby C, French PMW. Open Source High Content Analysis Utilizing Automated Fluorescence Lifetime Imaging Microscopy. J Vis Exp 2017:55119. [PMID: 28190060 PMCID: PMC5352269 DOI: 10.3791/55119] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
We present an open source high content analysis instrument utilizing automated fluorescence lifetime imaging (FLIM) for assaying protein interactions using Förster resonance energy transfer (FRET) based readouts of fixed or live cells in multiwell plates. This provides a means to screen for cell signaling processes read out using intramolecular FRET biosensors or intermolecular FRET of protein interactions such as oligomerization or heterodimerization, which can be used to identify binding partners. We describe here the functionality of this automated multiwell plate FLIM instrumentation and present exemplar data from our studies of HIV Gag protein oligomerization and a time course of a FRET biosensor in live cells. A detailed description of the practical implementation is then provided with reference to a list of hardware components and a description of the open source data acquisition software written in µManager. The application of FLIMfit, an open source MATLAB-based client for the OMERO platform, to analyze arrays of multiwell plate FLIM data is also presented. The protocols for imaging fixed and live cells are outlined and a demonstration of an automated multiwell plate FLIM experiment using cells expressing fluorescent protein-based FRET constructs is presented. This is complemented by a walk-through of the data analysis for this specific FLIM FRET data set.
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Affiliation(s)
- Frederik Görlitz
- Photonics Group, Department of Physics, Imperial College London;
| | - Douglas J Kelly
- Photonics Group, Department of Physics, Imperial College London
| | - Sean C Warren
- Photonics Group, Department of Physics, Imperial College London
| | - Dominic Alibhai
- Institute for Chemical Biology, Department of Chemistry, Imperial College London
| | - Lucien West
- MRC Clinical Sciences Centre, Hammersmith Hospital
| | - Sunil Kumar
- Photonics Group, Department of Physics, Imperial College London
| | | | - Ian Munro
- Photonics Group, Department of Physics, Imperial College London
| | - Edwin Garcia
- Photonics Group, Department of Physics, Imperial College London
| | - James McGinty
- Photonics Group, Department of Physics, Imperial College London
| | - Clifford Talbot
- Photonics Group, Department of Physics, Imperial College London
| | - Remigiusz A Serwa
- Chemical Biology Section, Department of Chemistry, Imperial College London
| | - Emmanuelle Thinon
- Chemical Biology Section, Department of Chemistry, Imperial College London
| | | | | | - Frank Stuhmeier
- Pfizer Global Research and Development, Pfizer Limited, Sandwich, Kent, UK
| | - Mark A A Neil
- Photonics Group, Department of Physics, Imperial College London
| | - Edward W Tate
- Chemical Biology Section, Department of Chemistry, Imperial College London
| | - Christopher Dunsby
- Photonics Group, Department of Physics, Imperial College London; Centre for Histopathology, Imperial College London
| | - Paul M W French
- Photonics Group, Department of Physics, Imperial College London
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17
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Lewis CA, Brault C, Peck B, Bensaad K, Griffiths B, Mitter R, Chakravarty P, East P, Dankworth B, Alibhai D, Harris AL, Schulze A. SREBP maintains lipid biosynthesis and viability of cancer cells under lipid- and oxygen-deprived conditions and defines a gene signature associated with poor survival in glioblastoma multiforme. Oncogene 2015; 34:5128-40. [PMID: 25619842 DOI: 10.1038/onc.2014.439] [Citation(s) in RCA: 159] [Impact Index Per Article: 17.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2014] [Revised: 11/04/2014] [Accepted: 12/05/2014] [Indexed: 12/16/2022]
Abstract
Oxygen and nutrient limitation are common features of the tumor microenvironment and are associated with cancer progression and induction of metastasis. The inefficient vascularization of tumor tissue also limits the penetration of other serum-derived factors, such as lipids and lipoproteins, which can be rate limiting for cell proliferation and survival. Here we have investigated the effect of hypoxia and serum deprivation on sterol regulatory element-binding protein (SREBP) activity and the expression of lipid metabolism genes in human glioblastoma multiforme (GBM) cancer cells. We found that SREBP transcriptional activity was induced by serum depletion both in normoxic and hypoxic cells and that activation of SREBP was required to maintain the expression of fatty acid and cholesterol metabolism genes under hypoxic conditions. Moreover, expression of stearoyl-CoA desaturase, the enzyme required for the generation of mono-unsaturated fatty acids, and fatty acid-binding protein 7, a regulator of glioma stem cell function, was strongly dependent on SREBP function. Inhibition of SREBP function blocked lipid biosynthesis in hypoxic cancer cells and impaired cell survival under hypoxia and in a three-dimensional spheroid model. Finally, gene expression analysis revealed that SREBP defines a gene signature that is associated with poor survival in glioblastoma.
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Affiliation(s)
- C A Lewis
- Gene Expression Analysis Laboratory, Cancer Research UK London Research Institute, London, UK
| | - C Brault
- Theodor-Boveri-Institute, Biocenter, Am Hubland, Würzburg, Germany
| | - B Peck
- Gene Expression Analysis Laboratory, Cancer Research UK London Research Institute, London, UK
| | - K Bensaad
- CRUK Growth Factor Group, The Weatherall Institute of Molecular Medicine, University of Oxford, Headington, Oxford, UK
| | - B Griffiths
- Gene Expression Analysis Laboratory, Cancer Research UK London Research Institute, London, UK
| | - R Mitter
- Bioinformatics and Biostatistics Service, Cancer Research UK London Research Institute, London, UK
| | - P Chakravarty
- Bioinformatics and Biostatistics Service, Cancer Research UK London Research Institute, London, UK
| | - P East
- Bioinformatics and Biostatistics Service, Cancer Research UK London Research Institute, London, UK
| | - B Dankworth
- Theodor-Boveri-Institute, Biocenter, Am Hubland, Würzburg, Germany
| | - D Alibhai
- Light Microscopy Core, Cancer Research UK London Research Institute, London, UK
| | - A L Harris
- CRUK Growth Factor Group, The Weatherall Institute of Molecular Medicine, University of Oxford, Headington, Oxford, UK
| | - A Schulze
- Gene Expression Analysis Laboratory, Cancer Research UK London Research Institute, London, UK
- Theodor-Boveri-Institute, Biocenter, Am Hubland, Würzburg, Germany
- Comprehensive Cancer Center Mainfranken Würzburg, Germany
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18
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Warren SC, Margineanu A, Alibhai D, Kelly DJ, Talbot C, Alexandrov Y, Munro I, Katan M, Dunsby C, French PMW. Rapid global fitting of large fluorescence lifetime imaging microscopy datasets. PLoS One 2013; 8:e70687. [PMID: 23940626 PMCID: PMC3734241 DOI: 10.1371/journal.pone.0070687] [Citation(s) in RCA: 136] [Impact Index Per Article: 12.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2013] [Accepted: 06/20/2013] [Indexed: 12/18/2022] Open
Abstract
Fluorescence lifetime imaging (FLIM) is widely applied to obtain quantitative information from fluorescence signals, particularly using Förster Resonant Energy Transfer (FRET) measurements to map, for example, protein-protein interactions. Extracting FRET efficiencies or population fractions typically entails fitting data to complex fluorescence decay models but such experiments are frequently photon constrained, particularly for live cell or in vivo imaging, and this leads to unacceptable errors when analysing data on a pixel-wise basis. Lifetimes and population fractions may, however, be more robustly extracted using global analysis to simultaneously fit the fluorescence decay data of all pixels in an image or dataset to a multi-exponential model under the assumption that the lifetime components are invariant across the image (dataset). This approach is often considered to be prohibitively slow and/or computationally expensive but we present here a computationally efficient global analysis algorithm for the analysis of time-correlated single photon counting (TCSPC) or time-gated FLIM data based on variable projection. It makes efficient use of both computer processor and memory resources, requiring less than a minute to analyse time series and multiwell plate datasets with hundreds of FLIM images on standard personal computers. This lifetime analysis takes account of repetitive excitation, including fluorescence photons excited by earlier pulses contributing to the fit, and is able to accommodate time-varying backgrounds and instrument response functions. We demonstrate that this global approach allows us to readily fit time-resolved fluorescence data to complex models including a four-exponential model of a FRET system, for which the FRET efficiencies of the two species of a bi-exponential donor are linked, and polarisation-resolved lifetime data, where a fluorescence intensity and bi-exponential anisotropy decay model is applied to the analysis of live cell homo-FRET data. A software package implementing this algorithm, FLIMfit, is available under an open source licence through the Open Microscopy Environment.
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Affiliation(s)
- Sean C Warren
- Department of Chemistry, Institute for Chemical Biology, Imperial College London, London, United Kingdom.
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19
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Alibhai D, Kelly DJ, Warren S, Kumar S, Margineau A, Serwa RA, Thinon E, Alexandrov Y, Murray EJ, Stuhmeier F, Tate EW, Neil MAA, Dunsby C, French PMW. Automated fluorescence lifetime imaging plate reader and its application to Förster resonant energy transfer readout of Gag protein aggregation. J Biophotonics 2013. [PMID: 23184449 DOI: 10.1002/jbio.v6.5] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/06/2023]
Abstract
Fluorescence lifetime measurements can provide quantitative readouts of local fluorophore environment and can be applied to biomolecular interactions via Förster resonant energy transfer (FRET). Fluorescence lifetime imaging (FLIM) can therefore provide a high content analysis (HCA) modality to map protein-protein interactions (PPIs) with applications in drug discovery, systems biology and basic research. We present here an automated multiwell plate reader able to perform rapid unsupervised optically sectioned FLIM of fixed and live biological samples and illustrate its potential to assay PPIs through application to Gag protein aggregation during the HIV life cycle. We demonstrate both hetero-FRET and homo-FRET readouts of protein aggregation and report the first quantitative evaluation of a FLIM HCA assay by generating dose response curves through addition of an inhibitor of Gag myristoylation. Z' factors exceeding 0.6 are realised for this FLIM FRET assay.
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Affiliation(s)
- Dominic Alibhai
- Institute of Chemical Biology, Department of Chemistry, Imperial College London, South Kensington Campus, London, UK
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20
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Alibhai D, Kelly DJ, Warren S, Kumar S, Margineau A, Serwa RA, Thinon E, Alexandrov Y, Murray EJ, Stuhmeier F, Tate EW, Neil MAA, Dunsby C, French PMW. Automated fluorescence lifetime imaging plate reader and its application to Förster resonant energy transfer readout of Gag protein aggregation. J Biophotonics 2013; 6:398-408. [PMID: 23184449 PMCID: PMC3660788 DOI: 10.1002/jbio.201200185] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/13/2012] [Revised: 10/05/2012] [Accepted: 10/14/2012] [Indexed: 05/29/2023]
Abstract
Fluorescence lifetime measurements can provide quantitative readouts of local fluorophore environment and can be applied to biomolecular interactions via Förster resonant energy transfer (FRET). Fluorescence lifetime imaging (FLIM) can therefore provide a high content analysis (HCA) modality to map protein-protein interactions (PPIs) with applications in drug discovery, systems biology and basic research. We present here an automated multiwell plate reader able to perform rapid unsupervised optically sectioned FLIM of fixed and live biological samples and illustrate its potential to assay PPIs through application to Gag protein aggregation during the HIV life cycle. We demonstrate both hetero-FRET and homo-FRET readouts of protein aggregation and report the first quantitative evaluation of a FLIM HCA assay by generating dose response curves through addition of an inhibitor of Gag myristoylation. Z' factors exceeding 0.6 are realised for this FLIM FRET assay.
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Affiliation(s)
- Dominic Alibhai
- Institute of Chemical Biology, Department of Chemistry, Imperial College LondonSouth Kensington Campus, London, SW7 2A, UK
| | - Douglas J Kelly
- Institute of Chemical Biology, Department of Chemistry, Imperial College LondonSouth Kensington Campus, London, SW7 2A, UK
| | - Sean Warren
- Institute of Chemical Biology, Department of Chemistry, Imperial College LondonSouth Kensington Campus, London, SW7 2A, UK
| | - Sunil Kumar
- Photonics Group, Department of Physics, Imperial College LondonSouth Kensington Campus, London, SW7 2AZ, UK
| | - Anca Margineau
- Photonics Group, Department of Physics, Imperial College LondonSouth Kensington Campus, London, SW7 2AZ, UK
| | - Remigiusz A Serwa
- Department of Chemistry, Imperial College LondonSouth Kensington Campus, London, SW7 2AZ, UK
| | - Emmanuelle Thinon
- Department of Chemistry, Imperial College LondonSouth Kensington Campus, London, SW7 2AZ, UK
| | - Yuriy Alexandrov
- Photonics Group, Department of Physics, Imperial College LondonSouth Kensington Campus, London, SW7 2AZ, UK
| | | | - Frank Stuhmeier
- Pfizer Worldwide Research and DevelopmentPfizer Limited, Sandwich, Kent, CT13 9NJ, UK
| | - Edward W Tate
- Department of Chemistry, Imperial College LondonSouth Kensington Campus, London, SW7 2AZ, UK
| | - Mark A A Neil
- Photonics Group, Department of Physics, Imperial College LondonSouth Kensington Campus, London, SW7 2AZ, UK
| | - Chris Dunsby
- Photonics Group, Department of Physics, Imperial College LondonSouth Kensington Campus, London, SW7 2AZ, UK
- Centre for Histopathology, Imperial College LondonDu Cane Rd, London, UK
| | - Paul M W French
- Photonics Group, Department of Physics, Imperial College LondonSouth Kensington Campus, London, SW7 2AZ, UK
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Kumar S, Alibhai D, Margineanu A, Laine R, Kennedy G, McGinty J, Warren S, Kelly D, Alexandrov Y, Munro I, Talbot C, Stuckey DW, Kimberly C, Viellerobe B, Lacombe F, Lam EWF, Taylor H, Dallman MJ, Stamp G, Murray EJ, Stuhmeier F, Sardini A, Katan M, Elson DS, Neil MAA, Dunsby C, French PMW. FLIM FRET technology for drug discovery: automated multiwell-plate high-content analysis, multiplexed readouts and application in situ. Chemphyschem 2011; 12:609-26. [PMID: 21337485 PMCID: PMC3084521 DOI: 10.1002/cphc.201000874] [Citation(s) in RCA: 54] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2010] [Revised: 12/07/2010] [Indexed: 11/10/2022]
Abstract
A fluorescence lifetime imaging (FLIM) technology platform intended to read out changes in Förster resonance energy transfer (FRET) efficiency is presented for the study of protein interactions across the drug-discovery pipeline. FLIM provides a robust, inherently ratiometric imaging modality for drug discovery that could allow the same sensor constructs to be translated from automated cell-based assays through small transparent organisms such as zebrafish to mammals. To this end, an automated FLIM multiwell-plate reader is described for high content analysis of fixed and live cells, tomographic FLIM in zebrafish and FLIM FRET of live cells via confocal endomicroscopy. For cell-based assays, an exemplar application reading out protein aggregation using FLIM FRET is presented, and the potential for multiple simultaneous FLIM (FRET) readouts in microscopy is illustrated.
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Affiliation(s)
- Sunil Kumar
- Photonics Group, Department of Physics, Imperial College London, London SW7 2AZ, UK.
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