1
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Hacker C, Sendra K, Keisham P, Filipescu T, Lucocq J, Salimi F, Ferguson S, Bhella D, MacNeill SA, Embley M, Lucocq J. Biogenesis, inheritance, and 3D ultrastructure of the microsporidian mitosome. Life Sci Alliance 2024; 7:e202201635. [PMID: 37903625 PMCID: PMC10618108 DOI: 10.26508/lsa.202201635] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [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: 07/27/2022] [Revised: 10/02/2023] [Accepted: 10/03/2023] [Indexed: 11/01/2023] Open
Abstract
During the reductive evolution of obligate intracellular parasites called microsporidia, a tiny remnant mitochondrion (mitosome) lost its typical cristae, organellar genome, and most canonical functions. Here, we combine electron tomography, stereology, immunofluorescence microscopy, and bioinformatics to characterise mechanisms of growth, division, and inheritance of this minimal mitochondrion in two microsporidia species (grown within a mammalian RK13 culture-cell host). Mitosomes of Encephalitozoon cuniculi (2-12/cell) and Trachipleistophora hominis (14-18/nucleus) displayed incremental/non-phasic growth and division and were closely associated with an organelle identified as equivalent to the fungal microtubule-organising centre (microsporidian spindle pole body; mSPB). The mitosome-mSPB association was resistant to treatment with microtubule-depolymerising drugs nocodazole and albendazole. Dynamin inhibitors (dynasore and Mdivi-1) arrested mitosome division but not growth, whereas bioinformatics revealed putative dynamins Drp-1 and Vps-1, of which, Vps-1 rescued mitochondrial constriction in dynamin-deficient yeast (Schizosaccharomyces pombe). Thus, microsporidian mitosomes undergo incremental growth and dynamin-mediated division and are maintained through ordered inheritance, likely mediated via binding to the microsporidian centrosome (mSPB).
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Affiliation(s)
- Christian Hacker
- https://ror.org/02wn5qz54 School of Medicine, University of St Andrews, St Andrews, UK
| | - Kacper Sendra
- Biosciences Institute, The Medical School, Catherine Cookson Building, Newcastle University, Newcastle upon Tyne, UK
| | - Priyanka Keisham
- https://ror.org/02wn5qz54 School of Medicine, University of St Andrews, St Andrews, UK
| | - Teodora Filipescu
- https://ror.org/02wn5qz54 School of Medicine, University of St Andrews, St Andrews, UK
| | - James Lucocq
- Department of Surgery, Dundee Medical School Ninewells Hospital, Dundee, UK
| | - Fatemeh Salimi
- https://ror.org/02wn5qz54 School of Medicine, University of St Andrews, St Andrews, UK
| | - Sophie Ferguson
- https://ror.org/02wn5qz54 School of Medicine, University of St Andrews, St Andrews, UK
| | - David Bhella
- MRC-University of Glasgow Centre for Virus Research, Glasgow, UK
| | - Stuart A MacNeill
- https://ror.org/02wn5qz54 School of Biology, University of St Andrews, St Andrews, UK
| | - Martin Embley
- Biosciences Institute, Centre for Bacterial Cell Biology, Baddiley-Clark Building, Newcastle University, Newcastle upon Tyne, UK
| | - John Lucocq
- https://ror.org/02wn5qz54 School of Medicine, University of St Andrews, St Andrews, UK
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2
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Hacker C, Mocchi M, Xiao J, Metzger B, Adkinson J, Pascuzzi B, Mathura R, Oswalt D, Watrous A, Bartoli E, Allawala A, Pirtle V, Fan X, Danstrom I, Shofty B, Banks G, Zhang Y, Armenta-Salas M, Mirpour K, Provenza N, Mathew S, Cohn J, Borton D, Goodman W, Pouratian N, Sheth S, Bijanki K. Aperiodic neural activity is a biomarker for depression severity. medRxiv 2023:2023.11.07.23298040. [PMID: 37986996 PMCID: PMC10659509 DOI: 10.1101/2023.11.07.23298040] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/22/2023]
Abstract
A reliable physiological biomarker for Major Depressive Disorder (MDD) is necessary to improve treatment success rates by shoring up variability in outcome measures. In this study, we establish a passive biomarker that tracks with changes in mood on the order of minutes to hours. We record from intracranial electrodes implanted deep in the brain - a surgical setting providing exquisite temporal and spatial sensitivity to detect this relationship in a difficult-to-measure brain area, the ventromedial prefrontal cortex (VMPFC). The aperiodic slope of the power spectral density captures the balance of activity across all frequency bands and is construed as a putative proxy for excitatory/inhibitory balance in the brain. This study demonstrates how shifts in aperiodic slope correlate with depression severity in a clinical trial of deep brain stimulation for treatment-resistant depression (TRD). The correlation between depression severity scores and aperiodic slope is significant in N=5 subjects, indicating that flatter (less negative) slopes correspond to reduced depression severity, especially in the ventromedial prefrontal cortex. This biomarker offers a new way to track patient response to MDD treatment, facilitating individualized therapies in both intracranial and non-invasive monitoring scenarios.
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Affiliation(s)
- C. Hacker
- Baylor College of Medicine Department of Neurosurgery
- Washington University in St. Louis Department of Neurosurgery
| | - M.M Mocchi
- Baylor College of Medicine Department of Neurosurgery
| | - J. Xiao
- Baylor College of Medicine Department of Neurosurgery
| | - B.A. Metzger
- Baylor College of Medicine Department of Neurosurgery
| | - J.A. Adkinson
- Baylor College of Medicine Department of Neurosurgery
| | - B.R. Pascuzzi
- Baylor College of Medicine Department of Neurosurgery
| | - R.C. Mathura
- Baylor College of Medicine Department of Neurosurgery
| | - D. Oswalt
- University of Pennsylvania Department of Neurosurgery
| | - A. Watrous
- Baylor College of Medicine Department of Neurosurgery
| | - E. Bartoli
- Baylor College of Medicine Department of Neurosurgery
| | - A. Allawala
- Brown University Department of Biomedical Engineering and Carney Institute for Brain Science
| | - V. Pirtle
- Baylor College of Medicine Department of Neurosurgery
| | - X. Fan
- Baylor College of Medicine Department of Neurosurgery
| | - I. Danstrom
- Baylor College of Medicine Department of Neurosurgery
| | - B. Shofty
- Baylor College of Medicine Department of Neurosurgery
| | - G. Banks
- Baylor College of Medicine Department of Neurosurgery
| | - Y. Zhang
- Baylor College of Medicine Department of Neurosurgery
| | | | - K. Mirpour
- University of Texas Southwestern, Department of Neurosurgery
| | - N. Provenza
- Baylor College of Medicine Department of Neurosurgery
| | - S. Mathew
- Baylor College of Medicine Department of Psychiatry
| | - J. Cohn
- University of Pittsburgh Department of Psychology
| | - D. Borton
- Brown University Department of Biomedical Engineering and Carney Institute for Brain Science
- Brown University Department of Veterans Affairs Center for Neurorestoration and Neurotechnology
| | - W. Goodman
- Baylor College of Medicine Department of Psychiatry
| | - N. Pouratian
- University of Texas Southwestern, Department of Neurosurgery
| | - S.A. Sheth
- Baylor College of Medicine Department of Neurosurgery
| | - K.R. Bijanki
- Baylor College of Medicine Department of Neurosurgery
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3
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Costello JL, Koster J, Silva BSC, Worthy HL, Schrader TA, Hacker C, Passmore J, Kuypers FA, Waterham HR, Schrader M. Differential roles for ACBD4 and ACBD5 in peroxisome-ER interactions and lipid metabolism. J Biol Chem 2023; 299:105013. [PMID: 37414147 PMCID: PMC10410513 DOI: 10.1016/j.jbc.2023.105013] [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: 01/09/2023] [Revised: 05/09/2023] [Accepted: 06/29/2023] [Indexed: 07/08/2023] Open
Abstract
Peroxisomes and the endoplasmic reticulum (ER) are intimately linked subcellular organelles, physically connected at membrane contact sites. While collaborating in lipid metabolism, for example, of very long-chain fatty acids (VLCFAs) and plasmalogens, the ER also plays a role in peroxisome biogenesis. Recent work identified tethering complexes on the ER and peroxisome membranes that connect the organelles. These include membrane contacts formed via interactions between the ER protein VAPB (vesicle-associated membrane protein-associated protein B) and the peroxisomal proteins ACBD4 and ACBD5 (acyl-coenzyme A-binding domain protein). Loss of ACBD5 has been shown to cause a significant reduction in peroxisome-ER contacts and accumulation of VLCFAs. However, the role of ACBD4 and the relative contribution these two proteins make to contact site formation and recruitment of VLCFAs to peroxisomes remain unclear. Here, we address these questions using a combination of molecular cell biology, biochemical, and lipidomics analyses following loss of ACBD4 or ACBD5 in HEK293 cells. We show that the tethering function of ACBD5 is not absolutely required for efficient peroxisomal β-oxidation of VLCFAs. We demonstrate that loss of ACBD4 does not reduce peroxisome-ER connections or result in the accumulation of VLCFAs. Instead, the loss of ACBD4 resulted in an increase in the rate of β-oxidation of VLCFAs. Finally, we observe an interaction between ACBD5 and ACBD4, independent of VAPB binding. Overall, our findings suggest that ACBD5 may act as a primary tether and VLCFA recruitment factor, whereas ACBD4 may have regulatory functions in peroxisomal lipid metabolism at the peroxisome-ER interface.
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Affiliation(s)
| | - Janet Koster
- Department of Clinical Chemistry, Laboratory Genetic Metabolic Diseases, Amsterdam University Medical Center Location University of Amsterdam, Amsterdam, The Netherlands
| | - Beatriz S C Silva
- Department of Biosciences, University of Exeter, Exeter, UK; Luxembourg Centre for Systems Biomedicine, Campus Belval | House of Biomedicine II, Université du Luxembourg, Belvaux, Luxembourg
| | | | | | | | - Josiah Passmore
- Department of Biosciences, University of Exeter, Exeter, UK; Division of Cell Biology, Utrecht University, Utrecht, The Netherlands
| | | | - Hans R Waterham
- Department of Clinical Chemistry, Laboratory Genetic Metabolic Diseases, Amsterdam University Medical Center Location University of Amsterdam, Amsterdam, The Netherlands.
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4
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Rowlands E, Galloway T, Cole M, Lewis C, Hacker C, Peck VL, Thorpe S, Blackbird S, Wolff GA, Manno C. Scoping intergenerational effects of nanoplastic on the lipid reserves of Antarctic krill embryos. Aquat Toxicol 2023; 261:106591. [PMID: 37329636 DOI: 10.1016/j.aquatox.2023.106591] [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] [Subscribe] [Scholar Register] [Received: 03/17/2023] [Revised: 05/05/2023] [Accepted: 05/24/2023] [Indexed: 06/19/2023]
Abstract
Antarctic krill (Euphausia superba) plays a central role in the Antarctic marine food web and biogeochemical cycles and has been identified as a species that is potentially vulnerable to plastic pollution. While plastic pollution has been acknowledged as a potential threat to Southern Ocean marine ecosystems, the effect of nanoplastics (<1000 nm) is poorly understood. Deleterious impacts of nanoplastic are predicted to be higher than that of larger plastics, due to their small size which enables their permeation of cell membranes and potentially provokes toxicity. Here, we investigated the intergenerational impact of exposing Antarctic krill to nanoplastics. We focused on whether embryonic energy resources were affected when gravid female krill were exposed to nanoplastic by determining lipid and fatty acid compositions of embryos produced in incubation. Embryos were collected from females who had spawned under three different exposure treatments (control, nanoplastic, nanoplastic + algae). Embryos collected from each maternal treatment were incubated for a further 6 days under three nanoplastic exposure treatments (control, low concentration nanoplastic, and high concentration nanoplastic). Nanoplastic additions to seawater did not impact lipid metabolism (total lipid or fatty acid composition) across the maternal or direct embryo treatments, and no interactive effects were observed. The provision of a food source during maternal exposure to nanoplastic had a positive effect on key fatty acids identified as important during embryogenesis, including higher total polyunsaturated fatty acids (PUFA), eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) when compared to the control and nanoplastic treatments. Whilst the short exposure time was ample for lipids from maternally digested algae to be incorporated into embryos, we discuss why the nanoplastic-fatty acid relationship may be more complex. Our study is the first to scope intergeneration effects of nanoplastic on Antarctic krill lipid and fatty acid reserves. From this, we suggest directions for future research including long term exposures, multi-stressor scenarios and exploring other critical energy reserves such as proteins.
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Affiliation(s)
- Emily Rowlands
- British Antarctic Survey, High Cross, Madingley Road, Cambridge CB3 0ET, United Kingdom.
| | - Tamara Galloway
- Biosciences, Faculty of Health and Life Sciences, Geoffrey Pope, University of Exeter, Stocker Road, Exeter EX4 4QD, United Kingdom
| | - Matthew Cole
- Plymouth Marine Laboratory, Prospect Place, Plymouth PL1 3DH, United Kingdom
| | - Ceri Lewis
- Biosciences, Faculty of Health and Life Sciences, Geoffrey Pope, University of Exeter, Stocker Road, Exeter EX4 4QD, United Kingdom
| | - Christian Hacker
- Biosciences, Faculty of Health and Life Sciences, Geoffrey Pope, University of Exeter, Stocker Road, Exeter EX4 4QD, United Kingdom
| | - Victoria L Peck
- British Antarctic Survey, High Cross, Madingley Road, Cambridge CB3 0ET, United Kingdom
| | - Sally Thorpe
- British Antarctic Survey, High Cross, Madingley Road, Cambridge CB3 0ET, United Kingdom
| | - Sabena Blackbird
- Department of Earth, Ocean and Ecological Sciences, University of Liverpool, Jane Herdman Building, 4 Brownlow Street, Liverpool L69 3GP, United Kingdom
| | - George A Wolff
- Department of Earth, Ocean and Ecological Sciences, University of Liverpool, Jane Herdman Building, 4 Brownlow Street, Liverpool L69 3GP, United Kingdom
| | - Clara Manno
- British Antarctic Survey, High Cross, Madingley Road, Cambridge CB3 0ET, United Kingdom.
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5
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Castledine M, Newbury A, Lewis R, Hacker C, Meaden S, Buckling A. Antagonistic Mobile Genetic Elements Can Counteract Each Other's Effects on Microbial Community Composition. mBio 2023; 14:e0046023. [PMID: 37022158 PMCID: PMC10127636 DOI: 10.1128/mbio.00460-23] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/07/2023] Open
Abstract
Bacteriophages ("phages") are hypothesized to be key drivers of bacterial population dynamics, driving microbial community composition, but empirical support for this is mixed. One reason why phages may have a less-than-expected impact on community composition is that many different phages and other mobile genetic elements (MGEs) interact with each bacterium. For instance, the same phage may have higher or lower costs to different bacterial strains or species. Assuming that resistance or susceptibility to MGE infection is not consistent across all MGEs, a simple prediction is that the net effect of MGEs on each bacterial taxon may converge with an increasing number of interactions with different MGEs. We formalized this prediction using in silico population dynamics simulations and then carried out experiments using three bacterial species, one generalist conjugative plasmid, and three species-specific phages. While the presence of only phages or only the plasmid altered community structure, these differential effects on community structure canceled out when both were together. The effects of MGEs were largely indirect and could not be explained by simple pairwise bipartite interactions (i.e., between each MGE and each bacterial species). Our results suggest that the effects of MGEs may be overestimated by studies that focus on a single MGE and not on interactions among multiple MGEs. IMPORTANCE While bacteriophages ("phages") are often cited as some of the key drivers of microbial diversity, evidence for this is greatly mixed. We demonstrate, in silico and experimentally, that the impact of phages, an example of a mobile genetic element (MGE), on community structure can diminish with increasing MGE diversity. This is because MGEs can have diverse effects on host fitness, and therefore as diversity increases, their individual effects cancel out, returning communities back to an MGE-free state. In addition, interactions in mixed-species and MGE communities could not be predicted from simple pairwise interactions, highlighting the difficulty in generalizing a MGE's effect from pairwise studies.
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Affiliation(s)
- Meaghan Castledine
- College of Life and Environmental Sciences, Environment and Sustainability Institute, University of Exeter, Penryn, United Kingdom
| | - Arthur Newbury
- College of Life and Environmental Sciences, Environment and Sustainability Institute, University of Exeter, Penryn, United Kingdom
| | - Rai Lewis
- College of Life and Environmental Sciences, Environment and Sustainability Institute, University of Exeter, Penryn, United Kingdom
| | - Christian Hacker
- Bioimaging Center, College of Life and Environmental Sciences, University of Exeter, Exeter, United Kingdom
| | - Sean Meaden
- College of Life and Environmental Sciences, Environment and Sustainability Institute, University of Exeter, Penryn, United Kingdom
| | - Angus Buckling
- College of Life and Environmental Sciences, Environment and Sustainability Institute, University of Exeter, Penryn, United Kingdom
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6
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Hacker C, Schrader TA, Schrader M. Ultrastructural Analysis and Quantification of Peroxisome-Organelle Contacts. Methods Mol Biol 2023; 2643:105-122. [PMID: 36952181 DOI: 10.1007/978-1-0716-3048-8_8] [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] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/24/2023]
Abstract
Transmission electron microscopy (TEM) has long been a vital technology to visualize the interaction of cellular compartments at the highest possible resolution. While this paved the way to describing organelles within the cellular context in detail, TEM has long been underused to generate quantitative data, analyzing those interactions as well as underlying mechanisms leading to their formation and modification. Here we describe a simple stereological method to unbiasedly assess the extent of organelle-organelle membrane contact sites, able to efficiently generate accurate and reproducible quantitative data from cultured mammalian cells prepared for TEM.
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Affiliation(s)
- Christian Hacker
- Faculty of Health and Life Sciences, Biosciences, University of Exeter, Exeter, Devon, UK.
| | - Tina A Schrader
- Faculty of Health and Life Sciences, Biosciences, University of Exeter, Exeter, Devon, UK
| | - Michael Schrader
- Faculty of Health and Life Sciences, Biosciences, University of Exeter, Exeter, Devon, UK.
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7
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de Assis LJ, Bain JM, Liddle C, Leaves I, Hacker C, Peres da Silva R, Yuecel R, Bebes A, Stead D, Childers DS, Pradhan A, Mackenzie K, Lagree K, Larcombe DE, Ma Q, Avelar GM, Netea MG, Erwig LP, Mitchell AP, Brown GD, Gow NAR, Brown AJP. Nature of β-1,3-Glucan-Exposing Features on Candida albicans Cell Wall and Their Modulation. mBio 2022; 13:e0260522. [PMID: 36218369 PMCID: PMC9765427 DOI: 10.1128/mbio.02605-22] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2022] [Accepted: 09/19/2022] [Indexed: 01/15/2023] Open
Abstract
Candida albicans exists as a commensal of mucosal surfaces and the gastrointestinal tract without causing pathology. However, this fungus is also a common cause of mucosal and systemic infections when antifungal immune defenses become compromised. The activation of antifungal host defenses depends on the recognition of fungal pathogen-associated molecular patterns (PAMPs), such as β-1,3-glucan. In C. albicans, most β-1,3-glucan is present in the inner cell wall, concealed by the outer mannan layer, but some β-1,3-glucan becomes exposed at the cell surface. In response to host signals, such as lactate, C. albicans induces the Xog1 exoglucanase, which shaves exposed β-1,3-glucan from the cell surface, thereby reducing phagocytic recognition. We show here that β-1,3-glucan is exposed at bud scars and punctate foci on the lateral wall of yeast cells, that this exposed β-1,3-glucan is targeted during phagocytic attack, and that lactate-induced masking reduces β-1,3-glucan exposure at bud scars and at punctate foci. β-1,3-Glucan masking depends upon protein kinase A (PKA) signaling. We reveal that inactivating PKA, or its conserved downstream effectors, Sin3 and Mig1/Mig2, affects the amounts of the Xog1 and Eng1 glucanases in the C. albicans secretome and modulates β-1,3-glucan exposure. Furthermore, perturbing PKA, Sin3, or Mig1/Mig2 attenuates the virulence of lactate-exposed C. albicans cells in Galleria. Taken together, the data are consistent with the idea that β-1,3-glucan masking contributes to Candida pathogenicity. IMPORTANCE Microbes that coexist with humans have evolved ways of avoiding or evading our immunological defenses. These include the masking by these microbes of their "pathogen-associated molecular patterns" (PAMPs), which are recognized as "foreign" and used to activate protective immunity. The commensal fungus Candida albicans masks the proinflammatory PAMP β-1,3-glucan, which is an essential component of its cell wall. Most of this β-1,3-glucan is hidden beneath an outer layer of the cell wall on these microbes, but some can become exposed at the fungal cell surface. Using high-resolution confocal microscopy, we examine the nature of the exposed β-1,3-glucan at C. albicans bud scars and at punctate foci on the lateral cell wall, and we show that these features are targeted by innate immune cells. We also reveal that downstream effectors of protein kinase A (Mig1/Mig2, Sin3) regulate the secretion of major glucanases, modulate the levels of β-1,3-glucan exposure, and influence the virulence of C. albicans in an invertebrate model of systemic infection. Our data support the view that β-1,3-glucan masking contributes to immune evasion and the virulence of a major fungal pathogen of humans.
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Affiliation(s)
- Leandro José de Assis
- Medical Research Council Centre for Medical Mycology, University of Exeter, Exeter, United Kingdom
| | - Judith M. Bain
- Aberdeen Fungal Group, Institute of Medical Sciences, University of Aberdeen, Aberdeen, United Kingdom
| | - Corin Liddle
- Bioimaging Unit, University of Exeter, Exeter, United Kingdom
| | - Ian Leaves
- Medical Research Council Centre for Medical Mycology, University of Exeter, Exeter, United Kingdom
| | | | - Roberta Peres da Silva
- Medical Research Council Centre for Medical Mycology, University of Exeter, Exeter, United Kingdom
| | - Raif Yuecel
- Exeter Centre for Cytomics, University of Exeter, Exeter, United Kingdom
| | - Attila Bebes
- Exeter Centre for Cytomics, University of Exeter, Exeter, United Kingdom
| | - David Stead
- Aberdeen Proteomics Facility, Rowett Institute, University of Aberdeen, Aberdeen, United Kingdom
| | - Delma S. Childers
- Aberdeen Fungal Group, Institute of Medical Sciences, University of Aberdeen, Aberdeen, United Kingdom
| | - Arnab Pradhan
- Medical Research Council Centre for Medical Mycology, University of Exeter, Exeter, United Kingdom
| | - Kevin Mackenzie
- Aberdeen Fungal Group, Institute of Medical Sciences, University of Aberdeen, Aberdeen, United Kingdom
| | - Katherine Lagree
- Department of Microbiology, University of Georgia, Athens, Georgia, USA
| | - Daniel E. Larcombe
- Medical Research Council Centre for Medical Mycology, University of Exeter, Exeter, United Kingdom
| | - Qinxi Ma
- Medical Research Council Centre for Medical Mycology, University of Exeter, Exeter, United Kingdom
| | - Gabriela Mol Avelar
- Aberdeen Fungal Group, Institute of Medical Sciences, University of Aberdeen, Aberdeen, United Kingdom
| | - Mihai G. Netea
- Department of Internal Medicine, Radboud University Medical Center, Nijmegen, Netherlands
- Radboud Center for Infectious Diseases, Radboud University Medical Center, Nijmegen, Netherlands
- Department for Immunology & Metabolism, Life and Medical Sciences Institute (LIMES), University of Bonn, Bonn, Germany
| | - Lars P. Erwig
- Aberdeen Fungal Group, Institute of Medical Sciences, University of Aberdeen, Aberdeen, United Kingdom
- Johnson-Johnson Innovation, EMEA Innovation Centre, London, United Kingdom
| | - Aaron P. Mitchell
- Department of Microbiology, University of Georgia, Athens, Georgia, USA
| | - Gordon D. Brown
- Medical Research Council Centre for Medical Mycology, University of Exeter, Exeter, United Kingdom
| | - Neil A. R. Gow
- Medical Research Council Centre for Medical Mycology, University of Exeter, Exeter, United Kingdom
| | - Alistair J. P. Brown
- Medical Research Council Centre for Medical Mycology, University of Exeter, Exeter, United Kingdom
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8
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Ribeiro F, Mitrano DM, Hacker C, Cherek P, Brigden K, Kaserzon SL, Thomas KV, Galloway TS. Short Depuration of Oysters Intended for Human Consumption Is Effective at Reducing Exposure to Nanoplastics. Environ Sci Technol 2022; 56:16716-16725. [PMID: 36383416 DOI: 10.1021/acs.est.2c02269] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/16/2023]
Abstract
Nanoplastics (NPs; <1 μm) have greater availability to marine organisms than microplastics (1-5000 μm). Understanding NP uptake and depuration in marine organisms intended for human consumption is imperative for food safety, but until now it has been limited due to analytical constraints. Oysters (Crassostrea gigas) were exposed to polystyrene NPs doped with palladium (Pd), allowing the measurements of their uptake into tissues by inductively coupled plasma mass spectrometry (ICP-MS) combined with electron microscopy. Oysters were exposed for 6 days (d) to "Smooth" or "Raspberry" NPs, followed by 30 d of depuration with the aim of assessing the NP concentration in C. gigas following exposure, inferring the accumulation and elimination rates, and understanding the clearance of Pd NPs during the depuration period. After 6 d, the most significant accumulation was found in the digestive gland (106.6 and 135.3 μg g-1 dw, for Smooth and Raspberry NPs, respectively) and showed the most evident depuration (elimination rate constant KSmooth = 2 d-1 and KRaspberry = 0.2 d-1). Almost complete depuration of the Raspberry NPs occurred after 30 d. While a post-harvesting depuration period of 24-48 h for oysters could potentially reduce the NP content by 75%, more research to validate these findings, including depuration studies of oysters from the field, is required to inform practices to reduce human exposure through consumption.
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Affiliation(s)
- Francisca Ribeiro
- Queensland Alliance for Environmental Health Sciences (QAEHS), The University of Queensland, 20 Cornwall Street, Woolloongabba, Brisbane, QLD 4102, Australia
- College of Life and Environmental Sciences, University of Exeter, Geoffrey Pope Building, Stocker Road, Exeter EX4 4QD, U.K
| | - Denise M Mitrano
- Department of Environmental Systems Science, ETH Zurich, Universitätstrasse 16, 8092 Zürich, Switzerland
| | - Christian Hacker
- Bioimaging Centre, Geoffrey Pope Building, University of Exeter, Stocker Road, Exeter EX4 4QD, U.K
| | - Paulina Cherek
- Bioimaging Centre, Geoffrey Pope Building, University of Exeter, Stocker Road, Exeter EX4 4QD, U.K
| | - Kevin Brigden
- Greenpeace Research Laboratories, College of Life and Environmental Sciences, Innovation Centre Phase 2, University of Exeter, Exeter EX4 4RN, U.K
| | - Sarit Leat Kaserzon
- Queensland Alliance for Environmental Health Sciences (QAEHS), The University of Queensland, 20 Cornwall Street, Woolloongabba, Brisbane, QLD 4102, Australia
| | - Kevin V Thomas
- Queensland Alliance for Environmental Health Sciences (QAEHS), The University of Queensland, 20 Cornwall Street, Woolloongabba, Brisbane, QLD 4102, Australia
| | - Tamara S Galloway
- College of Life and Environmental Sciences, University of Exeter, Geoffrey Pope Building, Stocker Road, Exeter EX4 4QD, U.K
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9
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Schrader TA, Carmichael RE, Islinger M, Costello JL, Hacker C, Bonekamp NA, Weishaupt JH, Andersen PM, Schrader M. PEX11β and FIS1 cooperate in peroxisome division independently of mitochondrial fission factor. J Cell Sci 2022; 135:275634. [PMID: 35678336 PMCID: PMC9377713 DOI: 10.1242/jcs.259924] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2022] [Accepted: 05/27/2022] [Indexed: 11/20/2022] Open
Abstract
Peroxisome membrane dynamics and division are essential to adapt the peroxisomal compartment to cellular needs. The peroxisomal membrane protein PEX11β (also known as PEX11B) and the tail-anchored adaptor proteins FIS1 (mitochondrial fission protein 1) and MFF (mitochondrial fission factor), which recruit the fission GTPase DRP1 (dynamin-related protein 1, also known as DNML1) to both peroxisomes and mitochondria, are key factors of peroxisomal division. The current model suggests that MFF is essential for peroxisome division, whereas the role of FIS1 is unclear. Here, we reveal that PEX11β can promote peroxisome division in the absence of MFF in a DRP1- and FIS1-dependent manner. We also demonstrate that MFF permits peroxisome division independently of PEX11β and restores peroxisome morphology in PEX11β-deficient patient cells. Moreover, targeting of PEX11β to mitochondria induces mitochondrial division, indicating the potential for PEX11β to modulate mitochondrial dynamics. Our findings suggest the existence of an alternative, MFF-independent pathway in peroxisome division and report a function for FIS1 in the division of peroxisomes. This article has an associated First Person interview with the first authors of the paper.
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Affiliation(s)
- Tina A. Schrader
- College of Life and Environmental Sciences, Biosciences, University of Exeter, Exeter EX4 4QD, UK
| | - Ruth E. Carmichael
- College of Life and Environmental Sciences, Biosciences, University of Exeter, Exeter EX4 4QD, UK
| | - Markus Islinger
- Institute of Neuroanatomy, Mannheim Centre for Translational Neuroscience, Medical Faculty Mannheim, University of Heidelberg, 68167 Mannheim, Germany
| | - Joseph L. Costello
- College of Life and Environmental Sciences, Biosciences, University of Exeter, Exeter EX4 4QD, UK
| | - Christian Hacker
- College of Life and Environmental Sciences, Biosciences, University of Exeter, Exeter EX4 4QD, UK
| | - Nina A. Bonekamp
- Institute of Neuroanatomy, Mannheim Centre for Translational Neuroscience, Medical Faculty Mannheim, University of Heidelberg, 68167 Mannheim, Germany
| | - Jochen H. Weishaupt
- Division of Neurodegeneration, Department of Neurology, Mannheim Center for Translational Neurosciences, Medical Faculty Mannheim, Heidelberg University, 68167 Mannheim, Germany
| | - Peter M. Andersen
- Department of Clinical Science, Neurosciences, Umeå University, Umeå SE-90185, Sweden
| | - Michael Schrader
- College of Life and Environmental Sciences, Biosciences, University of Exeter, Exeter EX4 4QD, UK
- Author for correspondence ()
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10
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Kors S, Hacker C, Bolton C, Maier R, Reimann L, Kitchener EJA, Warscheid B, Costello JL, Schrader M. Regulating peroxisome-ER contacts via the ACBD5-VAPB tether by FFAT motif phosphorylation and GSK3β. J Cell Biol 2022; 221:212956. [PMID: 35019937 DOI: 10.1083/jcb.202003143/212956] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2020] [Revised: 11/12/2021] [Accepted: 12/15/2021] [Indexed: 05/25/2023] Open
Abstract
Peroxisomes and the endoplasmic reticulum (ER) cooperate in cellular lipid metabolism. They form membrane contacts through interaction of the peroxisomal membrane protein ACBD5 (acyl-coenzyme A-binding domain protein 5) and the ER-resident protein VAPB (vesicle-associated membrane protein-associated protein B). ACBD5 binds to the major sperm protein domain of VAPB via its FFAT-like (two phenylalanines [FF] in an acidic tract) motif. However, molecular mechanisms, which regulate formation of these membrane contact sites, are unknown. Here, we reveal that peroxisome-ER associations via the ACBD5-VAPB tether are regulated by phosphorylation. We show that ACBD5-VAPB binding is phosphatase-sensitive and identify phosphorylation sites in the flanking regions and core of the FFAT-like motif, which alter interaction with VAPB-and thus peroxisome-ER contact sites-differently. Moreover, we demonstrate that GSK3β (glycogen synthase kinase-3 β) regulates this interaction. Our findings reveal for the first time a molecular mechanism for the regulation of peroxisome-ER contacts in mammalian cells and expand the current model of FFAT motifs and VAP interaction.
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Affiliation(s)
- Suzan Kors
- College of Life and Environmental Sciences, Biosciences, University of Exeter, Exeter, UK
| | - Christian Hacker
- College of Life and Environmental Sciences, Biosciences, University of Exeter, Exeter, UK
| | - Chloe Bolton
- College of Life and Environmental Sciences, Biosciences, University of Exeter, Exeter, UK
| | - Renate Maier
- Institute of Biology II, Biochemistry and Functional Proteomics, Faculty of Biology, University of Freiburg, Freiburg, Germany
| | - Lena Reimann
- Institute of Biology II, Biochemistry and Functional Proteomics, Faculty of Biology, University of Freiburg, Freiburg, Germany
| | - Emily J A Kitchener
- College of Life and Environmental Sciences, Biosciences, University of Exeter, Exeter, UK
| | - Bettina Warscheid
- Institute of Biology II, Biochemistry and Functional Proteomics, Faculty of Biology, University of Freiburg, Freiburg, Germany
- Centre for Integrative Biological Signalling Studies, University of Freiburg, Freiburg, Germany
| | - Joseph L Costello
- College of Life and Environmental Sciences, Biosciences, University of Exeter, Exeter, UK
| | - Michael Schrader
- College of Life and Environmental Sciences, Biosciences, University of Exeter, Exeter, UK
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11
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Kors S, Hacker C, Bolton C, Maier R, Reimann L, Kitchener EJA, Warscheid B, Costello JL, Schrader M. Regulating peroxisome-ER contacts via the ACBD5-VAPB tether by FFAT motif phosphorylation and GSK3β. J Cell Biol 2022; 221:212956. [PMID: 35019937 PMCID: PMC8759595 DOI: 10.1083/jcb.202003143] [Citation(s) in RCA: 19] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2020] [Revised: 11/12/2021] [Accepted: 12/15/2021] [Indexed: 12/18/2022] Open
Abstract
Peroxisomes and the endoplasmic reticulum (ER) cooperate in cellular lipid metabolism. They form membrane contacts through interaction of the peroxisomal membrane protein ACBD5 (acyl-coenzyme A–binding domain protein 5) and the ER-resident protein VAPB (vesicle-associated membrane protein–associated protein B). ACBD5 binds to the major sperm protein domain of VAPB via its FFAT-like (two phenylalanines [FF] in an acidic tract) motif. However, molecular mechanisms, which regulate formation of these membrane contact sites, are unknown. Here, we reveal that peroxisome–ER associations via the ACBD5-VAPB tether are regulated by phosphorylation. We show that ACBD5-VAPB binding is phosphatase-sensitive and identify phosphorylation sites in the flanking regions and core of the FFAT-like motif, which alter interaction with VAPB—and thus peroxisome–ER contact sites—differently. Moreover, we demonstrate that GSK3β (glycogen synthase kinase-3 β) regulates this interaction. Our findings reveal for the first time a molecular mechanism for the regulation of peroxisome–ER contacts in mammalian cells and expand the current model of FFAT motifs and VAP interaction.
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Affiliation(s)
- Suzan Kors
- College of Life and Environmental Sciences, Biosciences, University of Exeter, Exeter, UK
| | - Christian Hacker
- College of Life and Environmental Sciences, Biosciences, University of Exeter, Exeter, UK
| | - Chloe Bolton
- College of Life and Environmental Sciences, Biosciences, University of Exeter, Exeter, UK
| | - Renate Maier
- Institute of Biology II, Biochemistry and Functional Proteomics, Faculty of Biology, University of Freiburg, Freiburg, Germany
| | - Lena Reimann
- Institute of Biology II, Biochemistry and Functional Proteomics, Faculty of Biology, University of Freiburg, Freiburg, Germany
| | - Emily J A Kitchener
- College of Life and Environmental Sciences, Biosciences, University of Exeter, Exeter, UK
| | - Bettina Warscheid
- Institute of Biology II, Biochemistry and Functional Proteomics, Faculty of Biology, University of Freiburg, Freiburg, Germany.,Centre for Integrative Biological Signalling Studies, University of Freiburg, Freiburg, Germany
| | - Joseph L Costello
- College of Life and Environmental Sciences, Biosciences, University of Exeter, Exeter, UK
| | - Michael Schrader
- College of Life and Environmental Sciences, Biosciences, University of Exeter, Exeter, UK
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12
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Veldman A, Richter E, Hacker C, Fischer D. The Use of Off-Label Medications in Newborn Infants Despite an Approved Alternative Being Available—Results of a National Survey. Pharmacy 2022; 10:pharmacy10010019. [PMID: 35202069 PMCID: PMC8877519 DOI: 10.3390/pharmacy10010019] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [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: 12/14/2021] [Revised: 01/17/2022] [Accepted: 01/22/2022] [Indexed: 02/04/2023] Open
Abstract
Neonates continue to be treated with off-label or unlicensed drugs while in hospital. However, some medications that have previously been used in adults underwent clinical testing and licensure for use with a different indication in the neonatal and pediatric population. Almost always, the marketing of these newly approved substances in a niche indication is accompanied by a steep increase in the price of the compound. We investigated the use of the approved formulation or the cheaper off-label alternative of Ibuprofen (Pedea®), Propanolol (Hemangiol®) and Caffeine Citrate (Peyona®) in neonatal clinical practice by conducting a National Survey of 214 Perinatal Centers in Germany. We also assessed price differences between on- and off-label alternatives and the extend of the clinical development program of the on-label medication in the neonatal population. On-label medication was more frequently used than the off-label alternative in all indications (PDA: on-label to off-label ratio 1:0.26, Apnea: 1:0.56, Hemangioma 1:0.76). All sponsors did conduct placebo-controlled Phase III trials with efficacy and safety endpoints in the target population and the number of participants in the target population varied between 82 and 497. Costs for the three drugs in their approved and marketed formulations increased in median 405-fold compared with the corresponding off-label alternative. Overall, about one out of three neonatologists prescribed an off-label or non-approved drug to patients despite an alternative medication that is approved for the indication in the target population being available.
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Affiliation(s)
- Alex Veldman
- Department of Pediatrics, Helios HSK, 65199 Wiesbaden, Germany;
- Department of Pediatrics, Justus-Liebig University, 35385 Giessen, Germany;
- The Ritchie Centre, Hudson Institute of Medical Research, Monash University, Melbourne 3168, Australia
- Correspondence: ; Tel.: +49-611-43-2557
| | - Eva Richter
- Department of Pediatrics, Justus-Liebig University, 35385 Giessen, Germany;
| | | | - Doris Fischer
- Department of Pediatrics, Helios HSK, 65199 Wiesbaden, Germany;
- Department of Pediatrics, J.W. Goethe University Hospital, 60590 Frankfurt, Germany
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13
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Langley B, Halloran PR, Power A, Rickaby REM, Chana P, Diver P, Thornalley D, Hacker C, Love J. A new method for isolating and analysing coccospheres within sediment. Sci Rep 2020; 10:20727. [PMID: 33244023 PMCID: PMC7692543 DOI: 10.1038/s41598-020-77473-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [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: 04/29/2020] [Accepted: 11/06/2020] [Indexed: 11/25/2022] Open
Abstract
Size is a fundamental cellular trait that is important in determining phytoplankton physiological and ecological processes. Fossil coccospheres, the external calcite structure produced by the excretion of interlocking plates by the phytoplankton coccolithophores, can provide a rare window into cell size in the past. Coccospheres are delicate however and are therefore poorly preserved in sediment. We demonstrate a novel technique combining imaging flow cytometry and cross-polarised light (ISX+PL) to rapidly and reliably visually isolate and quantify the morphological characteristics of coccospheres from marine sediment by exploiting their unique optical and morphological properties. Imaging flow cytometry combines the morphological information provided by microscopy with high sample numbers associated with flow cytometry. High throughput imaging overcomes the constraints of labour-intensive manual microscopy and allows statistically robust analysis of morphological features and coccosphere concentration despite low coccosphere concentrations in sediments. Applying this technique to the fine-fraction of sediments, hundreds of coccospheres can be visually isolated quickly with minimal sample preparation. This approach has the potential to enable rapid processing of down-core sediment records and/or high spatial coverage from surface sediments and may prove valuable in investigating the interplay between climate change and coccolithophore physiological/ecological response.
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Affiliation(s)
- Beth Langley
- Geography, College of Life and Environmental Sciences, University of Exeter, Exeter, EX4 4RJ, UK
| | - Paul R Halloran
- Geography, College of Life and Environmental Sciences, University of Exeter, Exeter, EX4 4RJ, UK.
| | - Ann Power
- Biosciences, College of Life and Environmental Sciences, University of Exeter, Exeter, EX4 4QD, UK
| | - Rosalind E M Rickaby
- Department of Earth Sciences, University of Oxford, South Parks Road, Oxford, OX1 3AN, UK
| | - Prabhjoat Chana
- Luminex B.V., Het Zuiderkruis 1, 5215 MV, 's-Hertogenbosch, The Netherlands
| | - Poppy Diver
- Department of Earth Sciences, University of Oxford, South Parks Road, Oxford, OX1 3AN, UK
| | - David Thornalley
- Department of Geography, University College London, London, WC1H 9LG, UK
| | - Christian Hacker
- Biosciences, College of Life and Environmental Sciences, University of Exeter, Exeter, EX4 4QD, UK
| | - John Love
- Biosciences, College of Life and Environmental Sciences, University of Exeter, Exeter, EX4 4QD, UK
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14
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Hamied A, Alnedawy Q, Correia A, Hacker C, Ramsdale M, Hashimoto H, Kudoh T. Identification and Characterization of Highly Fluorescent Pigment Cells in Embryos of the Arabian Killifish ( Aphanius Dispar). iScience 2020; 23:101674. [PMID: 33145484 PMCID: PMC7593555 DOI: 10.1016/j.isci.2020.101674] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2020] [Revised: 09/15/2020] [Accepted: 10/09/2020] [Indexed: 11/26/2022] Open
Abstract
The Arabian killifish, Aphanius dispar, is a small tropical teleost fish living in wide range of habitats in sea water and fresh water in the Middle East. Here, we report extraordinary fluorescent pigment cells in the Arabian killifish embryo. These cells appear brown in transmitted light, yellowish white in reflected light, and as strong fluorescence in GFP and RFP filters. TEM and confocal microscopy analyses show the fluorescence emanates from leucosome-like pigment organelles. The cells express the gene encoding GTP cyclohydrolase (gch), a marker for leucophores and xanthophore. Gene knockdown and knockout of gch using morpholino or CRISPR-Cas9 induced loss of fluorescence in these embryos, indicating a crucial role of the enzyme and the associated pterine biosynthesis pathway in the generation of the fluorescence. We concluded that these cells are a highly fluorescent subtype of leucophores and have named them as fluoroleucophores. Arabian killifish embryos possess extremely fluorescent pigment cells The fluorescent pigment cells show characteristics in common with leucophores Gene knockout of GTP cyclohydrolase removes fluorescence from the pigment cells The novel pigment cells are termed fluoroleucophores
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Affiliation(s)
- Atyaf Hamied
- Biosciences, University of Exeter, Exeter, EX4 4QD, UK
| | | | - Ana Correia
- Department of Physiology, Development and Neuroscience, University of Cambridge, Cambridge, CB2 3EG, UK
| | | | - Mark Ramsdale
- Biosciences, University of Exeter, Exeter, EX4 4QD, UK
| | - Hisashi Hashimoto
- Division of Biological Science, Graduate School of Science, Nagoya University, Furo-cho, Chikusa-ku, Nagoya, 464-8602 Japan
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15
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Alshami IJJ, Ono Y, Correia A, Hacker C, Lange A, Scholpp S, Kawasaki M, Ingham PW, Kudoh T. Development of the electric organ in embryos and larvae of the knifefish, Brachyhypopomus gauderio. Dev Biol 2020; 466:99-108. [PMID: 32687892 PMCID: PMC7507958 DOI: 10.1016/j.ydbio.2020.06.010] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2019] [Revised: 06/04/2020] [Accepted: 06/23/2020] [Indexed: 11/05/2022]
Abstract
South American Gymnotiform knifefish possess electric organs that generate electric fields for electro-location and electro-communication. Electric organs in fish can be derived from either myogenic cells (myogenic electric organ/mEO) or neurogenic cells (neurogenic electric organ/nEO). To date, the embryonic development of EOs has remained obscure. Here we characterize the development of the mEO in the Gymnotiform bluntnose knifefish, Brachyhypopomus gauderio. We find that EO primordial cells arise during embryonic stages in the ventral edge of the tail myotome, translocate into the ventral fin and develop into syncytial electrocytes at early larval stages. We also describe a pair of thick nerve cords that flank the dorsal aorta, the location and characteristic morphology of which are reminiscent of the nEO in Apteronotid species, suggesting a common evolutionary origin of these tissues. Taken together, our findings reveal the embryonic origins of the mEO and provide a basis for elucidating the mechanisms of evolutionary diversification of electric charge generation by myogenic and neurogenic EOs. Developmental staging of the electric bluntnose knifefish, Brachyhypopomus gauderio embryos and larvae. The primordia of the myogenic electric organ originate in the ventral somite, migrate in the ventral fin and develop to the electric organ. Evolutionary conservation between the nerve codes in the B. gauderio and the neurogenic electric organs in the Apteronotidae.
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Affiliation(s)
- Ilham J J Alshami
- Biosciences, College of Life and Environmental Sciences, University of Exeter, Exeter, EX4 4QD, UK
| | - Yosuke Ono
- Biosciences, College of Life and Environmental Sciences, University of Exeter, Exeter, EX4 4QD, UK; Living Systems Institute, University of Exeter, Exeter, EX4 4QD, UK
| | - Ana Correia
- Department of Physiology, Development and Neuroscience, University of Cambridge, CB2 3EG, UK
| | - Christian Hacker
- Biosciences, College of Life and Environmental Sciences, University of Exeter, Exeter, EX4 4QD, UK
| | - Anke Lange
- Biosciences, College of Life and Environmental Sciences, University of Exeter, Exeter, EX4 4QD, UK
| | - Steffen Scholpp
- Living Systems Institute, University of Exeter, Exeter, EX4 4QD, UK
| | - Masashi Kawasaki
- Department of Biology, University of Virginia, Charlottesville, VA, 22904, USA
| | - Philip W Ingham
- Living Systems Institute, University of Exeter, Exeter, EX4 4QD, UK; Lee Kong Chian School of Medicine, Nanyang Technological University, Singapore
| | - Tetsuhiro Kudoh
- Biosciences, College of Life and Environmental Sciences, University of Exeter, Exeter, EX4 4QD, UK.
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16
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Passmore JB, Carmichael RE, Schrader TA, Godinho LF, Ferdinandusse S, Lismont C, Wang Y, Hacker C, Islinger M, Fransen M, Richards DM, Freisinger P, Schrader M. Mitochondrial fission factor (MFF) is a critical regulator of peroxisome maturation. Biochim Biophys Acta Mol Cell Res 2020; 1867:118709. [PMID: 32224193 PMCID: PMC7262603 DOI: 10.1016/j.bbamcr.2020.118709] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 09/12/2019] [Revised: 02/21/2020] [Accepted: 03/24/2020] [Indexed: 12/14/2022]
Abstract
Peroxisomes are highly dynamic subcellular compartments with important functions in lipid and ROS metabolism. Impaired peroxisomal function can lead to severe metabolic disorders with developmental defects and neurological abnormalities. Recently, a new group of disorders has been identified, characterised by defects in the membrane dynamics and division of peroxisomes rather than by loss of metabolic functions. However, the contribution of impaired peroxisome plasticity to the pathophysiology of those disorders is not well understood. Mitochondrial fission factor (MFF) is a key component of both the peroxisomal and mitochondrial division machinery. Patients with MFF deficiency present with developmental and neurological abnormalities. Peroxisomes (and mitochondria) in patient fibroblasts are highly elongated as a result of impaired organelle division. The majority of studies into MFF-deficiency have focused on mitochondrial dysfunction, but the contribution of peroxisomal alterations to the pathophysiology is largely unknown. Here, we show that MFF deficiency does not cause alterations to overall peroxisomal biochemical function. However, loss of MFF results in reduced import-competency of the peroxisomal compartment and leads to the accumulation of pre-peroxisomal membrane structures. We show that peroxisomes in MFF-deficient cells display alterations in peroxisomal redox state and intra-peroxisomal pH. Removal of elongated peroxisomes through induction of autophagic processes is not impaired. A mathematical model describing key processes involved in peroxisome dynamics sheds further light into the physical processes disturbed in MFF-deficient cells. The consequences of our findings for the pathophysiology of MFF-deficiency and related disorders with impaired peroxisome plasticity are discussed. Peroxisomes are highly elongated in cells from patients lacking fission factor MFF. Peroxisomal proteins are not uniformly distributed in highly elongated peroxisomes. Peroxisomal metabolism is unaltered in MFF-deficient patients. Peroxisomal elongations are stabilised through interaction with microtubules. Highly elongated peroxisomes are not spared from degradation.
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Affiliation(s)
| | | | | | | | - Sacha Ferdinandusse
- Laboratory Genetic Metabolic Diseases, Amsterdam University Medical Centre, University of Amsterdam, the Netherlands
| | - Celien Lismont
- Department of Cellular and Molecular Medicine, KU Leuven, Leuven, Belgium
| | - Yunhong Wang
- Institute of Neuroanatomy, Medical Faculty Manheim, University of Heidelberg, Mannheim, Germany
| | | | - Markus Islinger
- Institute of Neuroanatomy, Medical Faculty Manheim, University of Heidelberg, Mannheim, Germany
| | - Marc Fransen
- Department of Cellular and Molecular Medicine, KU Leuven, Leuven, Belgium
| | | | - Peter Freisinger
- Department of Pediatrics, Kreiskliniken Reutlingen, Reutlingen, Germany
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17
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Bishop A, Kamoshita M, Passmore JB, Hacker C, Schrader TA, Waterham HR, Costello JL, Schrader M. Fluorescent tools to analyse peroxisome-ER interactions in mammalian cells. ACTA ACUST UNITED AC 2019; 2. [PMID: 31198905 DOI: 10.1177/2515256419848641] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [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: 11/16/2022]
Abstract
Peroxisomes and the endoplasmic reticulum (ER) cooperate extensively in lipid-related metabolic pathways, and the ER also provides phospholipids to enable the peroxisomal membrane to expand prior to division. Recently, we identified peroxisomal proteins ACBD5 and ACBD4, and the ER protein VAPB as tethering components which physically interact to foster peroxisome-ER associations at membrane contact sites. Overexpression or loss of these tether proteins alters the extent of peroxisome-ER interactions, impacting on lipid exchange between these two compartments. To facilitate further studies into peroxisome-ER associations at the level of membrane contact sites, their role, composition and regulation, we have developed two fluorescence-based systems to monitor peroxisome-ER interactions. We modified a proximity ligation assay and a split-fluorescence reporter system using split superfolder green fluorescent protein. Using the proximity ligation assay we were able to measure changes in peroxisome-ER interactions whilst the split-fluorescence reporter was more limited and only allowed us to label ER-peroxisome contacts. We show that both techniques can be useful additions to the toolkit of methods to study peroxisome-ER associations and explore the relative merits of each.
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Affiliation(s)
- Alexa Bishop
- Biosciences, University of Exeter, Exeter, EX4 4QD, UK.,Centre for Vascular Biology, Institute of Molecular and Clinical Sciences, St George's, University of London, London SW17 0RE, UK
| | | | | | | | | | - Hans R Waterham
- Laboratory Genetic Metabolic Diseases, Department of Clinical Chemistry, Academic Medical Center, Amsterdam, The Netherlands
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18
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Siddiqi S, Trapp N, Hacker C, Kandala S, Leuthardt E, Carter A, Brody D. Functional connectivity changes with targeted rTMS of the dorsal attention network in TBI-associated depression. Brain Stimul 2019. [DOI: 10.1016/j.brs.2018.12.773] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022] Open
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19
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Brown AR, Green JM, Moreman J, Gunnarsson LM, Mourabit S, Ball J, Winter MJ, Trznadel M, Correia A, Hacker C, Perry A, Wood ME, Hetheridge MJ, Currie RA, Tyler CR. Cardiovascular Effects and Molecular Mechanisms of Bisphenol A and Its Metabolite MBP in Zebrafish. Environ Sci Technol 2019; 53:463-474. [PMID: 30520632 PMCID: PMC6333396 DOI: 10.1021/acs.est.8b04281] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/09/2018] [Revised: 11/12/2018] [Accepted: 12/06/2018] [Indexed: 05/03/2023]
Abstract
The plastic monomer bisphenol A (BPA) is one of the highest production volume chemicals in the world and is frequently detected in wildlife and humans, particularly children. BPA has been associated with numerous adverse health outcomes relating to its estrogenic and other hormonal properties, but direct causal links are unclear in humans and animal models. Here we simulated measured (1×) and predicted worst-case (10× ) maximum fetal exposures for BPA, or equivalent concentrations of its metabolite MBP, using fluorescent reporter embryo-larval zebrafish, capable of quantifying Estrogen Response Element (ERE) activation throughout the body. Heart valves were primary sites for ERE activation by BPA and MBP, and transcriptomic analysis of microdissected heart tissues showed that both chemicals targeted several molecular pathways constituting biomarkers for calcific aortic valve disease (CAVD), including extra-cellular matrix (ECM) alteration. ECM collagen deficiency and impact on heart valve structural integrity were confirmed by histopathology for high-level MBP exposure, and structural defects (abnormal curvature) of the atrio-ventricular valves corresponded with impaired cardiovascular function (reduced ventricular beat rate and blood flow). Our results are the first to demonstrate plausible mechanistic links between ERE activation in the heart valves by BPA's reactive metabolite MBP and the development of valvular-cardiovascular disease states.
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Affiliation(s)
- A. Ross Brown
- Biosciences,
College of Life and Environmental Sciences, University of Exeter, Geoffrey Pope, Stocker Road, Exeter, Devon EX4 4QD, U.K.
| | - Jon M. Green
- Biosciences,
College of Life and Environmental Sciences, University of Exeter, Geoffrey Pope, Stocker Road, Exeter, Devon EX4 4QD, U.K.
| | - John Moreman
- Biosciences,
College of Life and Environmental Sciences, University of Exeter, Geoffrey Pope, Stocker Road, Exeter, Devon EX4 4QD, U.K.
| | - Lina M. Gunnarsson
- Biosciences,
College of Life and Environmental Sciences, University of Exeter, Geoffrey Pope, Stocker Road, Exeter, Devon EX4 4QD, U.K.
| | - Sulayman Mourabit
- Biosciences,
College of Life and Environmental Sciences, University of Exeter, Geoffrey Pope, Stocker Road, Exeter, Devon EX4 4QD, U.K.
| | - Jonathan Ball
- Biosciences,
College of Life and Environmental Sciences, University of Exeter, Geoffrey Pope, Stocker Road, Exeter, Devon EX4 4QD, U.K.
| | - Matthew J. Winter
- Biosciences,
College of Life and Environmental Sciences, University of Exeter, Geoffrey Pope, Stocker Road, Exeter, Devon EX4 4QD, U.K.
| | - Maciej Trznadel
- Biosciences,
College of Life and Environmental Sciences, University of Exeter, Geoffrey Pope, Stocker Road, Exeter, Devon EX4 4QD, U.K.
| | - Ana Correia
- Biosciences,
College of Life and Environmental Sciences, University of Exeter, Geoffrey Pope, Stocker Road, Exeter, Devon EX4 4QD, U.K.
| | - Christian Hacker
- Biosciences,
College of Life and Environmental Sciences, University of Exeter, Geoffrey Pope, Stocker Road, Exeter, Devon EX4 4QD, U.K.
| | - Alexis Perry
- Biosciences,
College of Life and Environmental Sciences, University of Exeter, Geoffrey Pope, Stocker Road, Exeter, Devon EX4 4QD, U.K.
| | - Mark E. Wood
- Biosciences,
College of Life and Environmental Sciences, University of Exeter, Geoffrey Pope, Stocker Road, Exeter, Devon EX4 4QD, U.K.
| | - Malcolm J. Hetheridge
- Biosciences,
College of Life and Environmental Sciences, University of Exeter, Geoffrey Pope, Stocker Road, Exeter, Devon EX4 4QD, U.K.
| | - Richard A. Currie
- Jealott’s
Hill International Research Centre, Syngenta, Bracknell, Berkshire RG42
6EY, U.K.
| | - Charles R. Tyler
- Biosciences,
College of Life and Environmental Sciences, University of Exeter, Geoffrey Pope, Stocker Road, Exeter, Devon EX4 4QD, U.K.
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20
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Noventa S, Hacker C, Correia A, Drago C, Galloway T. Gold nanoparticles ingested by oyster larvae are internalized by cells through an alimentary endocytic pathway. Nanotoxicology 2018; 12:901-913. [PMID: 29996700 DOI: 10.1080/17435390.2018.1487601] [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] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/28/2022]
Abstract
The biological fate of nanoparticles (NPs) taken up by organisms from their environment is a crucial issue for assessing ecological hazard. Despite its importance, it has scarcely been addressed due to the technical difficulties of doing so in whole organism in vivo studies. Here, by using transmission electron microscopy and energy dispersive X-ray spectroscopy (TEM-EDS), we describe the key aspects that characterize the interaction between an aquatic organism of global ecological and economic importance, the early larval stage of the Japanese oyster (Crassostrea gigas), and model gold NPs dispersed in their environment. The small size of the model organism allowed for a high-throughput visualization of the subcellular distribution of NPs, providing a comprehensive and robust picture of the route of uptake, mechanism of cellular permeation, and the pathways of clearance counterbalancing bioaccumulation. We show that NPs are ingested by larvae and penetrate cells through alimentary pinocytic/phagocytic mechanisms. They undergo intracellular digestion and storage inside residual bodies, before excretion with feces or translocation to phagocytic coelomocytes of the visceral cavity for potential extrusion or further translocation. Our mechanistically-supported findings highlight the potential of oyster larvae and other organisms which feature intracellular digestion processes to be exposed to man-made NPs and thus any risks associated with their inherent toxicity.
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Affiliation(s)
- Seta Noventa
- a Department of Biosciences, College of Life and Environmental Sciences , University of Exeter , Exeter , UK
| | - Christian Hacker
- b Bioimaging Centre, College of Life and Environmental Sciences , University of Exeter , Exeter , UK
| | - Ana Correia
- b Bioimaging Centre, College of Life and Environmental Sciences , University of Exeter , Exeter , UK
| | - Claudia Drago
- a Department of Biosciences, College of Life and Environmental Sciences , University of Exeter , Exeter , UK
| | - Tamara Galloway
- a Department of Biosciences, College of Life and Environmental Sciences , University of Exeter , Exeter , UK
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21
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Sakulkoo W, Osés-Ruiz M, Oliveira Garcia E, Soanes DM, Littlejohn GR, Hacker C, Correia A, Valent B, Talbot NJ. A single fungal MAP kinase controls plant cell-to-cell invasion by the rice blast fungus. Science 2018; 359:1399-1403. [DOI: 10.1126/science.aaq0892] [Citation(s) in RCA: 110] [Impact Index Per Article: 18.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2017] [Accepted: 01/24/2018] [Indexed: 01/01/2023]
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22
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Noventa S, Hacker C, Rowe D, Elgy C, Galloway T. Dissolution and bandgap paradigms for predicting the toxicity of metal oxide nanoparticles in the marine environment: an in vivo study with oyster embryos. Nanotoxicology 2017; 12:63-78. [DOI: 10.1080/17435390.2017.1418920] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
Affiliation(s)
- Seta Noventa
- College of Life and Environmental Sciences, University of Exeter, Exeter, UK
| | - Christian Hacker
- College of Life and Environmental Sciences, Bioimaging Centre, University of Exeter, Exeter, UK
| | - Darren Rowe
- College of Life and Environmental Sciences, University of Exeter, Exeter, UK
| | - Christine Elgy
- Department of Geography, Earth and Environmental Sciences, Facility for Environmental Nanoscience Analysis and Characterization, University of Birmingham, Birmingham, UK
| | - Tamara Galloway
- College of Life and Environmental Sciences, University of Exeter, Exeter, UK
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23
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Steinberg G, Schuster M, Hacker C, Kilaru S, Correia A. ATP prevents Woronin bodies from sealing septal pores in unwounded cells of the fungus Zymoseptoria tritici. Cell Microbiol 2017; 19. [PMID: 28671740 PMCID: PMC5656841 DOI: 10.1111/cmi.12764] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2017] [Revised: 06/20/2017] [Accepted: 06/28/2017] [Indexed: 12/19/2022]
Abstract
Septa of filamentous ascomycetes are perforated by septal pores that allow communication between individual hyphal compartments. Upon injury, septal pores are plugged rapidly by Woronin bodies (WBs), thereby preventing extensive cytoplasmic bleeding. The mechanism by which WBs translocate into the pore is not known, but it has been suggested that wound‐induced cytoplasmic bleeding “flushes” WBs into the septal opening. Alternatively, contraction of septum‐associated tethering proteins may pull WBs into the septal pore. Here, we investigate WB dynamics in the wheat pathogen Zymoseptoria tritici. Ultrastructural studies showed that 3.4 ± 0.2 WBs reside on each side of a septum and that single WBs of 128.5 ± 3.6 nm in diameter seal the septal pore (41 ± 1.5 nm). Live cell imaging of green fluorescent ZtHex1, a major protein in WBs, and the integral plasma membrane protein ZtSso1 confirms WB translocation into the septal pore. This was associated with the occasional formation of a plasma membrane “balloon,” extruding into the dead cell, suggesting that the plasma membrane rapidly seals the wounded septal pore wound. Minor amounts of fluorescent ZtHex1‐enhanced green fluorescent protein (eGFP) appeared associated with the “ballooning” plasma membrane, indicating that cytoplasmic ZtHex1‐eGFP is recruited to the extending plasma membrane. Surprisingly, in ~15% of all cases, WBs moved from the ruptured cell into the septal pore. This translocation against the cytoplasmic flow suggests that an active mechanism drives WB plugging. Indeed, treatment of unwounded and intact cells with the respiration inhibitor carbonyl cyanide m‐chlorophenyl hydrazone induced WB translocation into the pores. Moreover, carbonyl cyanide m‐chlorophenyl hydrazone treatment recruited cytoplasmic ZtHex1‐eGFP to the lateral plasma membrane of the cells. Thus, keeping the WBs out of the septal pores, in Z. tritici, is an ATP‐dependent process.
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Affiliation(s)
- Gero Steinberg
- School of Biosciences, University of Exeter, Exeter, UK.,Department of Biology, University of Utrecht, Utrecht, The Netherlands
| | | | | | | | - Ana Correia
- Bioimaging Centre, University of Exeter, Exeter, UK
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24
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Asadi J, Ferguson S, Raja H, Hacker C, Marius P, Ward R, Pliotas C, Naismith J, Lucocq J. Enhanced imaging of lipid rich nanoparticles embedded in methylcellulose films for transmission electron microscopy using mixtures of heavy metals. Micron 2017; 99:40-48. [PMID: 28419915 PMCID: PMC5465805 DOI: 10.1016/j.micron.2017.03.019] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.3] [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] [Received: 03/04/2017] [Revised: 03/28/2017] [Accepted: 03/29/2017] [Indexed: 02/01/2023]
Abstract
Uranyl acetate/tungsten double stains are proposed for imaging lipid rich nanoparticle in TEM. Combined with methylcellulose embedment, the technique enhances membrane contrast. The technique works for liposomes, nanodiscs and bicelles. The double staining should improve quantification of lipid rich nanoparticles.
Synthetic and naturally occurring lipid-rich nanoparticles are of wide ranging importance in biomedicine. They include liposomes, bicelles, nanodiscs, exosomes and virus particles. The quantitative study of these particles requires methods for high-resolution visualization of the whole population. One powerful imaging method is cryo-EM of vitrified samples, but this is technically demanding, requires specialized equipment, provides low contrast and does not reveal all particles present in a population. Another approach is classical negative stain-EM, which is more accessible but is difficult to standardize for larger lipidic structures, which are prone to artifacts of structure collapse and contrast variability. A third method uses embedment in methylcellulose films containing uranyl acetate as a contrasting agent. Methylcellulose embedment has been widely used for contrasting and supporting cryosections but only sporadically for visualizing lipid rich vesicular structures such as endosomes and exosomes. Here we present a simple methylcellulose-based method for routine and comprehensive visualization of synthetic lipid rich nanoparticles preparations, such as liposomes, bicelles and nanodiscs. It combines a novel double-staining mixture of uranyl acetate (UA) and tungsten-based electron stains (namely phosphotungstic acid (PTA) or sodium silicotungstate (STA)) with methylcellulose embedment. While the methylcellulose supports the delicate lipid structures during drying, the addition of PTA or STA to UA provides significant enhancement in lipid structure display and contrast as compared to UA alone. This double staining method should aid routine structural evaluation and quantification of lipid rich nanoparticles structures.
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Affiliation(s)
- Jalal Asadi
- School of Medicine, University of St Andrews, St. Andrews, Fife, KY16 9TF, UK
| | - Sophie Ferguson
- School of Medicine, University of St Andrews, St. Andrews, Fife, KY16 9TF, UK
| | - Hussain Raja
- School of Medicine, University of St Andrews, St. Andrews, Fife, KY16 9TF, UK
| | - Christian Hacker
- School of Medicine, University of St Andrews, St. Andrews, Fife, KY16 9TF, UK
| | - Phedra Marius
- Biomedical Sciences Research Complex, North Haugh, University of St. Andrews, St. Andrews, Scotland, UK
| | - Richard Ward
- Biomedical Sciences Research Complex, North Haugh, University of St. Andrews, St. Andrews, Scotland, UK
| | - Christos Pliotas
- Biomedical Sciences Research Complex, North Haugh, University of St. Andrews, St. Andrews, Scotland, UK
| | - James Naismith
- Biomedical Sciences Research Complex, North Haugh, University of St. Andrews, St. Andrews, Scotland, UK
| | - John Lucocq
- School of Medicine, University of St Andrews, St. Andrews, Fife, KY16 9TF, UK.
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25
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Costello JL, Castro IG, Hacker C, Schrader TA, Metz J, Zeuschner D, Azadi AS, Godinho LF, Costina V, Findeisen P, Manner A, Islinger M, Schrader M. ACBD5 and VAPB mediate membrane associations between peroxisomes and the ER. J Cell Biol 2017; 216:331-342. [PMID: 28108524 PMCID: PMC5294785 DOI: 10.1083/jcb.201607055] [Citation(s) in RCA: 165] [Impact Index Per Article: 23.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2016] [Revised: 10/31/2016] [Accepted: 12/22/2016] [Indexed: 01/20/2023] Open
Abstract
Costello et al. identify ACBD5 and VAPB as key components of a peroxisome–ER tether in mammalian cells. Disruption of this tethering complex leads to reduced peroxisomal membrane expansion and increased peroxisomal movement. Peroxisomes (POs) and the endoplasmic reticulum (ER) cooperate in cellular lipid metabolism and form tight structural associations, which were first observed in ultrastructural studies decades ago. PO–ER associations have been suggested to impact on a diverse number of physiological processes, including lipid metabolism, phospholipid exchange, metabolite transport, signaling, and PO biogenesis. Despite their fundamental importance to cell metabolism, the mechanisms by which regions of the ER become tethered to POs are unknown, in particular in mammalian cells. Here, we identify the PO membrane protein acyl-coenzyme A–binding domain protein 5 (ACBD5) as a binding partner for the resident ER protein vesicle-associated membrane protein-associated protein B (VAPB). We show that ACBD5–VAPB interaction regulates PO–ER associations. Moreover, we demonstrate that loss of PO–ER association perturbs PO membrane expansion and increases PO movement. Our findings reveal the first molecular mechanism for establishing PO–ER associations in mammalian cells and report a new function for ACBD5 in PO–ER tethering.
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Affiliation(s)
| | - Inês G Castro
- Biosciences, University of Exeter, Exeter EX4 4QD, England, UK
| | | | - Tina A Schrader
- Biosciences, University of Exeter, Exeter EX4 4QD, England, UK
| | - Jeremy Metz
- Biosciences, University of Exeter, Exeter EX4 4QD, England, UK
| | - Dagmar Zeuschner
- Max Planck Institute for Molecular Biomedicine, 48149 Muenster, Germany
| | - Afsoon S Azadi
- Biosciences, University of Exeter, Exeter EX4 4QD, England, UK
| | - Luis F Godinho
- Biosciences, University of Exeter, Exeter EX4 4QD, England, UK
| | - Victor Costina
- Institute for Clinical Chemistry, Medical Faculty Mannheim, University of Heidelberg, 68167 Mannheim, Germany
| | - Peter Findeisen
- Institute for Clinical Chemistry, Medical Faculty Mannheim, University of Heidelberg, 68167 Mannheim, Germany
| | - Andreas Manner
- Institute of Neuroanatomy, Center for Biomedicine and Medical Technology Mannheim, Medical Faculty Mannheim, University of Heidelberg, 68167 Mannheim, Germany
| | - Markus Islinger
- Institute of Neuroanatomy, Center for Biomedicine and Medical Technology Mannheim, Medical Faculty Mannheim, University of Heidelberg, 68167 Mannheim, Germany
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26
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Freibert SA, Goldberg AV, Hacker C, Molik S, Dean P, Williams TA, Nakjang S, Long S, Sendra K, Bill E, Heinz E, Hirt RP, Lucocq JM, Embley TM, Lill R. Evolutionary conservation and in vitro reconstitution of microsporidian iron-sulfur cluster biosynthesis. Nat Commun 2017; 8:13932. [PMID: 28051091 PMCID: PMC5216125 DOI: 10.1038/ncomms13932] [Citation(s) in RCA: 58] [Impact Index Per Article: 8.3] [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: 08/05/2016] [Accepted: 11/14/2016] [Indexed: 12/22/2022] Open
Abstract
Microsporidians are obligate intracellular parasites that have minimized their genome content and sub-cellular structures by reductive evolution. Here, we demonstrate that cristae-deficient mitochondria (mitosomes) of Trachipleistophora hominis are the functional site of iron–sulfur cluster (ISC) assembly, which we suggest is the essential task of these organelles. Cell fractionation, fluorescence imaging and immunoelectron microscopy demonstrate that mitosomes contain a complete pathway for [2Fe–2S] cluster biosynthesis that we biochemically reconstituted using purified mitosomal ISC proteins. The T. hominis cytosolic iron–sulfur protein assembly (CIA) pathway includes the essential Cfd1–Nbp35 scaffold complex that assembles a [4Fe–4S] cluster as shown by spectroscopic methods in vitro. Phylogenetic analyses reveal that the ISC and CIA pathways are predominantly bacterial, but their cytosolic and nuclear target Fe/S proteins are mainly archaeal. This mixed evolutionary history of Fe/S-related proteins and pathways, and their strong conservation among highly reduced parasites, provides compelling evidence for the ancient chimeric ancestry of eukaryotes.
The functions of the highly reduced mitochondria (mitosomes) of microsporidians are not well-characterized. Here, the authors show that the Trachipleistophora hominis mitosome is the site of iron–sulfur cluster assembly and that its retention is likely linked to its role in cytosolic and nuclear iron–sulfur protein maturation.
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Affiliation(s)
- Sven-A Freibert
- Institut für Zytobiologie und Zytopathologie, Philipps-Universität, Robert-Koch-Strasse 6, Marburg 35032, Germany
| | - Alina V Goldberg
- Institute for Cell and Molecular Biosciences, University of Newcastle, Newcastle upon Tyne NE2 4HH, UK
| | - Christian Hacker
- School of Medicine, University of St Andrews, St. Andrews KY16 9TF, UK.,Bioimaging Centre, College of Life and Environmental Sciences, University of Exeter, Stocker Road, Exeter EX4 4QD, UK
| | - Sabine Molik
- Institut für Zytobiologie und Zytopathologie, Philipps-Universität, Robert-Koch-Strasse 6, Marburg 35032, Germany
| | - Paul Dean
- Institute for Cell and Molecular Biosciences, University of Newcastle, Newcastle upon Tyne NE2 4HH, UK
| | - Tom A Williams
- Institute for Cell and Molecular Biosciences, University of Newcastle, Newcastle upon Tyne NE2 4HH, UK
| | - Sirintra Nakjang
- Institute for Cell and Molecular Biosciences, University of Newcastle, Newcastle upon Tyne NE2 4HH, UK
| | - Shaojun Long
- Institute for Cell and Molecular Biosciences, University of Newcastle, Newcastle upon Tyne NE2 4HH, UK
| | - Kacper Sendra
- Institute for Cell and Molecular Biosciences, University of Newcastle, Newcastle upon Tyne NE2 4HH, UK
| | - Eckhard Bill
- Max-Planck-Institut für Bioanorganische Chemie, Stiftstrasse 34-36, Mülheim an der Ruhr 45470, Germany
| | - Eva Heinz
- Institute for Cell and Molecular Biosciences, University of Newcastle, Newcastle upon Tyne NE2 4HH, UK
| | - Robert P Hirt
- Institute for Cell and Molecular Biosciences, University of Newcastle, Newcastle upon Tyne NE2 4HH, UK
| | - John M Lucocq
- School of Medicine, University of St Andrews, St. Andrews KY16 9TF, UK
| | - T Martin Embley
- Institute for Cell and Molecular Biosciences, University of Newcastle, Newcastle upon Tyne NE2 4HH, UK
| | - Roland Lill
- Institut für Zytobiologie und Zytopathologie, Philipps-Universität, Robert-Koch-Strasse 6, Marburg 35032, Germany.,LOEWE Zentrum für Synthetische Mikrobiologie SynMikro, Hans-Meerwein-Strasse, Marburg 35043, Germany
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27
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Aroso M, Agricola B, Hacker C, Schrader M. Addendum to the paper: Proteoglycans support proper granule formation in pancreatic AR42J cells. Histochem Cell Biol 2016; 146:115. [PMID: 27286989 DOI: 10.1007/s00418-016-1452-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
Affiliation(s)
- Miguel Aroso
- Centre for Cell Biology and Department of Biology, University of Aveiro, Campus Universitário de Santiago, 3810-193, Aveiro, Portugal
| | - Brigitte Agricola
- Department of Cell Biology and Cell Pathology, University of Marburg, 35037, Marburg, Germany
| | - Christian Hacker
- College of Life and Environmental Sciences, Biosciences, University of Exeter, Geoffrey Pope Building, Stocker Road, Exeter, EX4 4QD, UK
| | - Michael Schrader
- Centre for Cell Biology and Department of Biology, University of Aveiro, Campus Universitário de Santiago, 3810-193, Aveiro, Portugal. .,College of Life and Environmental Sciences, Biosciences, University of Exeter, Geoffrey Pope Building, Stocker Road, Exeter, EX4 4QD, UK.
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28
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Lin C, Schuster M, Guimaraes SC, Ashwin P, Schrader M, Metz J, Hacker C, Gurr SJ, Steinberg G. Active diffusion and microtubule-based transport oppose myosin forces to position organelles in cells. Nat Commun 2016; 7:11814. [PMID: 27251117 PMCID: PMC4895713 DOI: 10.1038/ncomms11814] [Citation(s) in RCA: 63] [Impact Index Per Article: 7.9] [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: 11/13/2015] [Accepted: 05/03/2016] [Indexed: 11/26/2022] Open
Abstract
Even distribution of peroxisomes (POs) and lipid droplets (LDs) is critical to their role in lipid and reactive oxygen species homeostasis. How even distribution is achieved remains elusive, but diffusive motion and directed motility may play a role. Here we show that in the fungus Ustilago maydis ∼95% of POs and LDs undergo diffusive motions. These movements require ATP and involve bidirectional early endosome motility, indicating that microtubule-associated membrane trafficking enhances diffusion of organelles. When early endosome transport is abolished, POs and LDs drift slowly towards the growing cell end. This pole-ward drift is facilitated by anterograde delivery of secretory cargo to the cell tip by myosin-5. Modelling reveals that microtubule-based directed transport and active diffusion support distribution, mobility and mixing of POs. In mammalian COS-7 cells, microtubules and F-actin also counteract each other to distribute POs. This highlights the importance of opposing cytoskeletal forces in organelle positioning in eukaryotes. The mechanisms underlying the positioning of eukaryotic organelles remain elusive. Here Lin et al. use imaging and a mathematical model to show that microtubule-based transport and active diffusion and actin-based polar drift act together to facilitate even distribution of peroxisomes in filamentous fungi.
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Affiliation(s)
- Congping Lin
- School of Biosciences, University of Exeter, Stocker Road, Exeter EX4 4QD, UK.,Mathematics, University of Exeter, North Park Road, Exeter EX4 4QF, UK
| | - Martin Schuster
- School of Biosciences, University of Exeter, Stocker Road, Exeter EX4 4QD, UK
| | | | - Peter Ashwin
- Mathematics, University of Exeter, North Park Road, Exeter EX4 4QF, UK
| | - Michael Schrader
- School of Biosciences, University of Exeter, Stocker Road, Exeter EX4 4QD, UK
| | - Jeremy Metz
- School of Biosciences, University of Exeter, Stocker Road, Exeter EX4 4QD, UK
| | - Christian Hacker
- School of Biosciences, University of Exeter, Stocker Road, Exeter EX4 4QD, UK
| | - Sarah Jane Gurr
- School of Biosciences, University of Exeter, Stocker Road, Exeter EX4 4QD, UK
| | - Gero Steinberg
- School of Biosciences, University of Exeter, Stocker Road, Exeter EX4 4QD, UK
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29
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Riches A, Powis S, Mullen P, Harrison D, Hacker C, Lucocq J, Bowness J, Chapman A, Cameron R, McLornan L, Chinn DJ, Leung S. Human urinary exosomes in bladder cancer patients: properties, concentrations and possible clinical application. Bladder (San Franc) 2016. [DOI: 10.14440/bladder.2016.63] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
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30
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Arastoo M, Hacker C, Popovics P, Lucocq JM, Stewart AJ. Erratum to: Phospholipase C-η2 interacts with nuclear and cytoplasmic LIMK-1 during retinoic acid-stimulated neurite growth. Histochem Cell Biol 2016; 145:681. [PMID: 26873005 PMCID: PMC4969822 DOI: 10.1007/s00418-016-1418-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Affiliation(s)
- Mohammed Arastoo
- School of Medicine, Medical and Biological Sciences Building, North Haugh, University of St Andrews, St Andrews, Fife, KY16 9TF, UK
| | - Christian Hacker
- School of Medicine, Medical and Biological Sciences Building, North Haugh, University of St Andrews, St Andrews, Fife, KY16 9TF, UK.,Bioimaging Centre, Geoffrey Pope Building, College of Life and Environmental Sciences, University of Exeter, Exeter, EX4 4QD, UK
| | - Petra Popovics
- School of Medicine, Medical and Biological Sciences Building, North Haugh, University of St Andrews, St Andrews, Fife, KY16 9TF, UK.,Veterans Affairs Medical Center, Miami, FL, 33125, USA
| | - John M Lucocq
- School of Medicine, Medical and Biological Sciences Building, North Haugh, University of St Andrews, St Andrews, Fife, KY16 9TF, UK
| | - Alan J Stewart
- School of Medicine, Medical and Biological Sciences Building, North Haugh, University of St Andrews, St Andrews, Fife, KY16 9TF, UK.
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31
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Arastoo M, Hacker C, Popovics P, Lucocq JM, Stewart AJ. Phospholipase C-η2 interacts with nuclear and cytoplasmic LIMK-1 during retinoic acid-stimulated neurite growth. Histochem Cell Biol 2015; 145:163-73. [PMID: 26671787 PMCID: PMC4735258 DOI: 10.1007/s00418-015-1390-7] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 11/24/2015] [Indexed: 01/22/2023]
Abstract
Neurite growth is central to the formation and differentiation of functional neurons, and recently, an essential role for phospholipase C-η2 (PLCη2) in neuritogenesis was revealed. Here we investigate the function of PLCη2 in neuritogenesis using Neuro2A cells, which upon stimulation with retinoic acid differentiate and form neurites. We first investigated the role of the PLCη2 calcium-binding EF-hand domain, a domain that is known to be required for PLCη2 activation. To do this, we quantified neurite outgrowth in Neuro2A cells, stably overexpressing wild-type PLCη2 and D256A (EF-hand) and H460Q (active site) PLCη2 mutants. Retinoic acid-induced neuritogenesis was highly dependent on PLCη2 activity, with the H460Q mutant exhibiting a strong dominant-negative effect. Expression of the D256A mutant had little effect on neurite growth relative to the control, suggesting that calcium-directed activation of PLCη2 is not essential to this process. We next investigated which cellular compartments contain endogenous PLCη2 by comparing immunoelectron microscopy signals over control and knockdown cell lines. When signals were analyzed to reveal specific labeling for PLCη2, it was found to be localized predominantly over the nucleus and cytosol. Furthermore in these compartments (and also in growing neurites), a proximity ligand assay revealed that PLCη2 specifically interacts with LIMK-1 in Neuro2A cells. Taken together, these data emphasize the importance of the PLCη2 EF-hand domain and articulation of PLCη2 with LIMK-1 in regulating neuritogenesis.
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Affiliation(s)
- Mohammed Arastoo
- School of Medicine, Medical and Biological Sciences Building, North Haugh, University of St Andrews, St Andrews, Fife, KY16 9TF, UK
| | - Christian Hacker
- School of Medicine, Medical and Biological Sciences Building, North Haugh, University of St Andrews, St Andrews, Fife, KY16 9TF, UK
- Bioimaging Centre, Geoffrey Pope Building, College of Life and Environmental Sciences, University of Exeter, Exeter, EX4 4QD, UK
| | - Petra Popovics
- School of Medicine, Medical and Biological Sciences Building, North Haugh, University of St Andrews, St Andrews, Fife, KY16 9TF, UK
- Veterans Affairs Medical Center, Miami, FL, 33125, USA
| | - John M Lucocq
- School of Medicine, Medical and Biological Sciences Building, North Haugh, University of St Andrews, St Andrews, Fife, KY16 9TF, UK
| | - Alan J Stewart
- School of Medicine, Medical and Biological Sciences Building, North Haugh, University of St Andrews, St Andrews, Fife, KY16 9TF, UK.
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32
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Riches A, Powis S, Mullen P, Harrison D, Hacker C, Lucocq J, Bowness J, Chapman A, Cameron R, McLornan L, Chinn DJ, Leung S. Human urinary exosomes in bladder cancer patients: properties, concentrations and possible clinical application. Bladder (San Franc) 2015. [DOI: 10.14440/bladder.0.63] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
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33
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Aroso M, Agricola B, Hacker C, Schrader M. Proteoglycans support proper granule formation in pancreatic acinar cells. Histochem Cell Biol 2015; 144:331-46. [PMID: 26105026 DOI: 10.1007/s00418-015-1339-x] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 06/07/2015] [Indexed: 12/31/2022]
Abstract
Zymogen granules (ZG) are specialized organelles in the exocrine pancreas which allow digestive enzyme storage and regulated secretion. The molecular mechanisms of their biogenesis and the sorting of zymogens are still incompletely understood. Here, we investigated the role of proteoglycans in granule formation and secretion of zymogens in pancreatic AR42J cells, an acinar model system. Cupromeronic Blue cytochemistry and biochemical studies revealed an association of proteoglycans primarily with the granule membrane. Removal of proteoglycans by carbonate treatment led to a loss of membrane curvature indicating a supportive role in the maintenance of membrane shape and stability. Chemical inhibition of proteoglycan synthesis impaired the formation of normal electron-dense granules in AR42J cells and resulted in the formation of unusually small granule structures. These structures still contained the zymogen carboxypeptidase, a cargo molecule of secretory granules, but migrated to lighter fractions after density gradient centrifugation. Furthermore, the basal secretion of amylase was increased in AR42J cells after inhibitor treatment. In addition, irregular-shaped granules appeared in pancreatic lobules. We conclude that the assembly of a proteoglycan scaffold at the ZG membrane is supporting efficient packaging of zymogens and the proper formation of stimulus-competent storage granules in acinar cells of the pancreas.
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Affiliation(s)
- Miguel Aroso
- Centre for Cell Biology and Department of Biology, University of Aveiro, Campus Universitário de Santiago, 3810-193, Aveiro, Portugal
| | - Brigitte Agricola
- Department of Cell Biology and Cell Pathology, University of Marburg, 35037, Marburg, Germany
| | - Christian Hacker
- College of Life and Environmental Sciences, Biosciences, University of Exeter, Geoffrey Pope Building, Stocker Road, Exeter, EX4 4QD, UK
| | - Michael Schrader
- Centre for Cell Biology and Department of Biology, University of Aveiro, Campus Universitário de Santiago, 3810-193, Aveiro, Portugal. .,College of Life and Environmental Sciences, Biosciences, University of Exeter, Geoffrey Pope Building, Stocker Road, Exeter, EX4 4QD, UK.
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Ward R, Pliotas C, Branigan E, Hacker C, Rasmussen A, Hagelueken G, Booth IR, Miller S, Lucocq J, Naismith JH, Schiemann O. Probing the structure of the mechanosensitive channel of small conductance in lipid bilayers with pulsed electron-electron double resonance. Biophys J 2014; 106:834-42. [PMID: 24559986 PMCID: PMC3944623 DOI: 10.1016/j.bpj.2014.01.008] [Citation(s) in RCA: 43] [Impact Index Per Article: 4.3] [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: 09/17/2013] [Revised: 01/03/2014] [Accepted: 01/07/2014] [Indexed: 01/16/2023] Open
Abstract
Mechanosensitive channel proteins are important safety valves against osmotic shock in bacteria, and are involved in sensing touch and sound waves in higher organisms. The mechanosensitive channel of small conductance (MscS) has been extensively studied. Pulsed electron-electron double resonance (PELDOR or DEER) of detergent-solubilized protein confirms that as seen in the crystal structure, the outer ring of transmembrane helices do not pack against the pore-forming helices, creating an apparent void. The relevance of this void to the functional form of MscS in the bilayer is the subject of debate. Here, we report PELDOR measurements of MscS reconstituted into two lipid bilayer systems: nanodiscs and bicelles. The distance measurements from multiple mutants derived from the PELDOR data are consistent with the detergent-solution arrangement of the protein. We conclude, therefore, that the relative positioning of the transmembrane helices is preserved in mimics of the cell bilayer, and that the apparent voids are not an artifact of detergent solution but a property of the protein that will have to be accounted for in any molecular mechanism of gating.
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Affiliation(s)
- Richard Ward
- Centre for Biomolecular Sciences, University of St. Andrews, St. Andrews, Scotland
| | - Christos Pliotas
- Centre for Biomolecular Sciences, University of St. Andrews, St. Andrews, Scotland
| | - Emma Branigan
- Centre for Biomolecular Sciences, University of St. Andrews, St. Andrews, Scotland
| | - Christian Hacker
- School of Medicine, University of St. Andrews, St. Andrews, Scotland
| | - Akiko Rasmussen
- Institute of Medical Sciences, University of Aberdeen, Aberdeen, Scotland
| | - Gregor Hagelueken
- Institute of Physical and Theoretical Chemistry, University of Bonn, Bonn, Germany
| | - Ian R Booth
- Institute of Medical Sciences, University of Aberdeen, Aberdeen, Scotland
| | - Samantha Miller
- Institute of Medical Sciences, University of Aberdeen, Aberdeen, Scotland
| | - John Lucocq
- School of Medicine, University of St. Andrews, St. Andrews, Scotland
| | - James H Naismith
- Centre for Biomolecular Sciences, University of St. Andrews, St. Andrews, Scotland.
| | - Olav Schiemann
- Institute of Physical and Theoretical Chemistry, University of Bonn, Bonn, Germany; Centre for Biomolecular Sciences, University of St. Andrews, St. Andrews, Scotland.
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Lucocq JM, Mayhew TM, Schwab Y, Steyer AM, Hacker C. Systems biology in 3D space--enter the morphome. Trends Cell Biol 2014; 25:59-64. [PMID: 25455351 DOI: 10.1016/j.tcb.2014.09.008] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2014] [Revised: 09/24/2014] [Accepted: 09/25/2014] [Indexed: 11/27/2022]
Abstract
Systems-based understanding of living organisms depends on acquiring huge datasets from arrays of genes, transcripts, proteins, and lipids. These data, referred to as 'omes', are assembled using 'omics' methodologies. Currently a comprehensive, quantitative view of cellular and organellar systems in 3D space at nanoscale/molecular resolution is missing. We introduce here the term 'morphome' for the distribution of living matter within a 3D biological system, and 'morphomics' for methods of collecting 3D data systematically and quantitatively. A sampling-based approach termed stereology currently provides rapid, precise, and minimally biased morphomics. We propose that stereology solves the 'big data' problem posed by emerging wide-scale electron microscopy (EM) and can establish quantitative links between the newer nanoimaging platforms such as electron tomography, cryo-EM, and correlative microscopy.
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Affiliation(s)
- John M Lucocq
- School of Medicine, University of St Andrews, St Andrews KY16 9TF, UK.
| | - Terry M Mayhew
- School of Life Sciences, Queen's Medical Centre, University of Nottingham, Nottingham NG7 2UH, UK
| | - Yannick Schwab
- Electron Microscopy Core Facility, Cell Biology and Biophysics Unit, European Molecular Biology Laboratory, Meyerhofstrasse 1, 69117 Heidelberg, Germany
| | - Anna M Steyer
- Electron Microscopy Core Facility, Cell Biology and Biophysics Unit, European Molecular Biology Laboratory, Meyerhofstrasse 1, 69117 Heidelberg, Germany
| | - Christian Hacker
- School of Medicine, University of St Andrews, St Andrews KY16 9TF, UK
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36
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Quinn SD, Dalgarno PA, Cameron RT, Hedley GJ, Hacker C, Lucocq JM, Baillie GS, Samuel IDW, Penedo JC. Real-time probing of β-amyloid self-assembly and inhibition using fluorescence self-quenching between neighbouring dyes. ACTA ACUST UNITED AC 2014; 10:34-44. [DOI: 10.1039/c3mb70272c] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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Abstract
Immunoelectron microscopy (immuno-EM) using gold labeling on sections is a powerful technique for mapping the distribution of proteins, lipids, carbohydrates, and nucleic acids in intact biological systems. The gold particles comprise a useful and readily quantifiable digital readout. Simply applying a labeling reagent (antibody or other affinity probe) to an ultrathin section yields a pattern of gold signal over the biological structures displayed in the section. This initial (raw) distribution of gold signal contains both specific and nonspecific labeling. Here we describe a method for removing nonspecific labeling to leave the target-specific signal. This specific labeling distribution better reflects the "real" distribution of the cell component of interest.
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Affiliation(s)
- Christian Hacker
- School of Medicine and Biology, St. Andrew University, Scotland, UK
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38
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Hacker C, Howell M, Bhella D, Lucocq J. Strategies for maximizing ATP supply in the microsporidian Encephalitozoon cuniculi: direct binding of mitochondria to the parasitophorous vacuole and clustering of the mitochondrial porin VDAC. Cell Microbiol 2013; 16:565-79. [PMID: 24245785 PMCID: PMC4233961 DOI: 10.1111/cmi.12240] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2013] [Revised: 10/11/2013] [Accepted: 11/11/2013] [Indexed: 11/29/2022]
Abstract
Microsporidia are obligate intracellular parasites with extremely reduced genomes and a dependence on host-derived ATP. The microsporidium Encephalitozoon cuniculi proliferates within a membranous vacuole and we investigated how the ATP supply is optimized at the vacuole-host interface. Using spatial EM quantification (stereology), we found a single layer of mitochondria coating substantial proportions of the parasitophorous vacuole. Mitochondrial binding occurred preferentially over the vegetative 'meront' stages of the parasite, which bulged into the cytoplasm, thereby increasing the membrane surface available for mitochondrial interaction. In a broken cell system mitochondrial binding was maintained and was typified by electron dense structures (< 10 nm long) bridging between outer mitochondrial and vacuole membranes. In broken cells mitochondrial binding was sensitive to a range of protease treatments. The function of directly bound mitochondria, as measured by the membrane potential sensitive dye JC-1, was indistinguishable from other mitochondria in the cell although there was a generalized depression of the membrane potential in infected cells. Finally, quantitative immuno-EM revealed that the ATP-delivering mitochondrial porin, VDAC, was concentrated atthe mitochondria-vacuole interaction site. Thus E. cuniculi appears to maximize ATP supply by direct binding of mitochondria to the parasitophorous vacuole bringing this organelle within 0.020 microns of the growing vegetative form of the parasite. ATP-delivery is further enhanced by clustering of ATP transporting porins in those regions of the outer mitochondrial membrane lying closest to the parasite.
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Affiliation(s)
- Christian Hacker
- School of Medicine, University of St Andrews, North Haugh, St Andrews, Fife, KF16 9TF, UK
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Abstract
Over the last few years, two guideline articles have been published with recommendations for assessing autophagy. These articles contained advice on quantification of autophagy by electron microscopy and proposed using thin slices for quantifying autophagic structures. Here, we expand on what can and cannot be quantified using single 2D slices and give some suggestions for efficient and minimally biased approaches for quantifying this fascinating and important process. We recommend that the journal Autophagy follow other journals in demanding stringent random sampling design and application of unbiased design-based quantification when reviewing submitted manuscripts.
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Affiliation(s)
- John Milton Lucocq
- Nanomorphomics Group; School of Medicine; University of St. Andrews; North Haugh, Fife UK
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Vollmar F, Hacker C, Zahedi RP, Sickmann A, Ewald A, Scheer U, Dabauvalle MC. Assembly of nuclear pore complexes mediated by major vault protein. J Cell Sci 2009; 122:780-6. [PMID: 19240118 DOI: 10.1242/jcs.039529] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023] Open
Abstract
During interphase growth of eukaryotic cells, nuclear pore complexes (NPCs) are continuously incorporated into the intact nuclear envelope (NE) by mechanisms that are largely unknown. De novo formation of NPCs involves local fusion events between the inner and outer nuclear membrane, formation of a transcisternal membranous channel of defined diameter and the coordinated assembly of hundreds of nucleoporins into the characteristic NPC structure. Here we have used a cell-free system based on Xenopus egg extract, which allows the experimental separation of nuclear-membrane assembly and NPC formation. Nuclei surrounded by a closed double nuclear membrane, but devoid of NPCs, were first reconstituted from chromatin and a specific membrane fraction. Insertion of NPCs into the preformed pore-free nuclei required cytosol containing soluble nucleoporins or nucleoporin subcomplexes and, quite unexpectedly, major vault protein (MVP). MVP is the main component of vaults, which are ubiquitous barrel-shaped particles of enigmatic function. Our results implicate MVP, and thus also vaults, in NPC biogenesis and provide a functional explanation for the association of a fraction of vaults with the NE and specifically with NPCs in intact cells.
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Affiliation(s)
- Friederike Vollmar
- Division of Electron Microscopy, Biocenter, University of Würzburg, 97074 Würzburg, Germany
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Cincarek T, Gruhn R, Hacker C, Nöth E, Nakamura S. Automatic pronunciation scoring of words and sentences independent from the non-native’s first language. COMPUT SPEECH LANG 2009. [DOI: 10.1016/j.csl.2008.03.001] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
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42
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Graf AH, Pickel H, Hacker C, Staudach A. Invasives Adenokarzinom der Cervix uteri bei einem 17jährigen Mädchen - Ein Fallbericht. Geburtshilfe Frauenheilkd 2008. [DOI: 10.1055/s-2007-1023013] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022] Open
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Cardis E, Vrijheid M, Blettner M, Gilbert E, Hakama M, Hill C, Howe G, Kaldor J, Muirhead CR, Schubauer-Berigan M, Yoshimura T, Bermann F, Cowper G, Fix J, Hacker C, Heinmiller B, Marshall M, Thierry-Chef I, Utterback D, Ahn YO, Amoros E, Ashmore P, Auvinen A, Bae JM, Bernar J, Biau A, Combalot E, Deboodt P, Diez Sacristan A, Eklöf M, Engels H, Engholm G, Gulis G, Habib RR, Holan K, Hyvonen H, Kerekes A, Kurtinaitis J, Malker H, Martuzzi M, Mastauskas A, Monnet A, Moser M, Pearce MS, Richardson DB, Rodriguez-Artalejo F, Rogel A, Tardy H, Telle-Lamberton M, Turai I, Usel M, Veress K. The 15-Country Collaborative Study of Cancer Risk among Radiation Workers in the Nuclear Industry: estimates of radiation-related cancer risks. Radiat Res 2007; 167:396-416. [PMID: 17388693 DOI: 10.1667/rr0553.1] [Citation(s) in RCA: 447] [Impact Index Per Article: 26.3] [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: 01/20/2006] [Accepted: 11/02/2006] [Indexed: 12/15/2022]
Abstract
A 15-Country collaborative cohort study was conducted to provide direct estimates of cancer risk following protracted low doses of ionizing radiation. Analyses included 407,391 nuclear industry workers monitored individually for external radiation and 5.2 million person-years of follow-up. A significant association was seen between radiation dose and all-cause mortality [excess relative risk (ERR) 0.42 per Sv, 90% CI 0.07, 0.79; 18,993 deaths]. This was mainly attributable to a dose-related increase in all cancer mortality (ERR/Sv 0.97, 90% CI 0.28, 1.77; 5233 deaths). Among 31 specific types of malignancies studied, a significant association was found for lung cancer (ERR/Sv 1.86, 90% CI 0.49, 3.63; 1457 deaths) and a borderline significant (P = 0.06) association for multiple myeloma (ERR/Sv 6.15, 90% CI <0, 20.6; 83 deaths) and ill-defined and secondary cancers (ERR/Sv 1.96, 90% CI -0.26, 5.90; 328 deaths). Stratification on duration of employment had a large effect on the ERR/Sv, reflecting a strong healthy worker survivor effect in these cohorts. This is the largest analytical epidemiological study of the effects of low-dose protracted exposures to ionizing radiation to date. Further studies will be important to better assess the role of tobacco and other occupational exposures in our risk estimates.
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Affiliation(s)
- E Cardis
- International Agency for Research on Cancer, Lyon, France
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44
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Thierry-Chef I, Marshall M, Fix JJ, Bermann F, Gilbert ES, Hacker C, Heinmiller B, Murray W, Pearce MS, Utterback D, Bernar K, Deboodt P, Eklof M, Griciene B, Holan K, Hyvonen H, Kerekes A, Lee MC, Moser M, Pernicka F, Cardis E. The 15-Country Collaborative Study of Cancer Risk among Radiation Workers in the Nuclear Industry: Study of Errors in Dosimetry. Radiat Res 2007; 167:380-95. [PMID: 17388692 DOI: 10.1667/rr0552.1] [Citation(s) in RCA: 60] [Impact Index Per Article: 3.5] [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: 01/20/2006] [Accepted: 10/19/2006] [Indexed: 11/03/2022]
Abstract
To provide direct estimates of cancer risk after low-dose protracted exposure to ionizing radiation, a large-scale epidemiological study of nuclear industry workers was conducted in 15 countries. As part of this study, identification and quantification of errors in historical recorded doses was conducted based on a review of dosimetric practices and technologies in participating facilities. The main sources of errors on doses from "high-energy" photons (100-3000 keV) were identified as the response of dosimeters in workplace exposure conditions and historical calibration practices. Errors related to dosimetry technology and radiation fields were quantified to derive period- and facility-specific estimates of bias and uncertainties in recorded doses. This was based on (1) an evaluation of predominant workplace radiation from measurement studies and dosimetry expert assessment and (2) an estimation of the energy and geometry response of dosimeters used historically in study facilities. Coefficients were derived to convert recorded doses to H(p) (10) and organ dose, taking into account different aspects of the calibration procedures. A parametric, lognormal error structure model was developed to describe errors in doses as a function of facility and time period. Doses from other radiation types, particularly neutrons and radionuclide intake, could not be adequately reconstructed in the framework of the 15-Country Study. Workers with substantial doses from these radiation types were therefore identified and excluded from analyses. Doses from "lower-energy" photons (<100 keV) and from "higher-energy" photons (>3 MeV) were estimated to be small.
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Affiliation(s)
- I Thierry-Chef
- International Agency for Research on Cancer, Lyon, France
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Cardis E, Vrijheid M, Blettner M, Gilbert E, Hakama M, Hill C, Howe G, Kaldor J, Muirhead CR, Schubauer-Berigan M, Yoshimura T, Bermann F, Cowper G, Fix J, Hacker C, Heinmiller B, Marshall M, Thierry-Chef I, Utterback D, Ahn YO, Amoros E, Ashmore P, Auvinen A, Bae JM, Solano JB, Biau A, Combalot E, Deboodt P, Diez Sacristan A, Eklof M, Engels H, Engholm G, Gulis G, Habib R, Holan K, Hyvonen H, Kerekes A, Kurtinaitis J, Malker H, Martuzzi M, Mastauskas A, Monnet A, Moser M, Pearce MS, Richardson DB, Rodriguez-Artalejo F, Rogel A, Tardy H, Telle-Lamberton M, Turai I, Usel M, Veress K. Risk of cancer after low doses of ionising radiation: retrospective cohort study in 15 countries. BMJ 2005; 331:77. [PMID: 15987704 PMCID: PMC558612 DOI: 10.1136/bmj.38499.599861.e0] [Citation(s) in RCA: 373] [Impact Index Per Article: 19.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
OBJECTIVES To provide direct estimates of risk of cancer after protracted low doses of ionising radiation and to strengthen the scientific basis of radiation protection standards for environmental, occupational, and medical diagnostic exposures. DESIGN Multinational retrospective cohort study of cancer mortality. SETTING Cohorts of workers in the nuclear industry in 15 countries. PARTICIPANTS 407 391 workers individually monitored for external radiation with a total follow-up of 5.2 million person years. MAIN OUTCOME MEASUREMENTS Estimates of excess relative risks per sievert (Sv) of radiation dose for mortality from cancers other than leukaemia and from leukaemia excluding chronic lymphocytic leukaemia, the main causes of death considered by radiation protection authorities. RESULTS The excess relative risk for cancers other than leukaemia was 0.97 per Sv, 95% confidence interval 0.14 to 1.97. Analyses of causes of death related or unrelated to smoking indicate that, although confounding by smoking may be present, it is unlikely to explain all of this increased risk. The excess relative risk for leukaemia excluding chronic lymphocytic leukaemia was 1.93 per Sv (< 0 to 8.47). On the basis of these estimates, 1-2% of deaths from cancer among workers in this cohort may be attributable to radiation. CONCLUSIONS These estimates, from the largest study of nuclear workers ever conducted, are higher than, but statistically compatible with, the risk estimates used for current radiation protection standards. The results suggest that there is a small excess risk of cancer, even at the low doses and dose rates typically received by nuclear workers in this study.
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Affiliation(s)
- E Cardis
- International Agency for Research on Cancer, Lyons, France.
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Nathan T, Rose T, Khanna A, Hacker C, Simoni J, Duran MJ, Wesson DE. 328 INCREASED DIETARY PROTEIN AS CASEIN BUT NOT SOY AUGMENTS RENAL ENDOTHELIN PRODUCTION. J Investig Med 2005. [DOI: 10.2310/6650.2005.00006.327] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
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Koritschoner NP, Alvarez-Dolado M, Kurz SM, Heikenwälder MF, Hacker C, Vogel F, Muñoz A, Zenke M. Thyroid hormone regulates the obesity gene tub. EMBO Rep 2001; 2:499-504. [PMID: 11415982 PMCID: PMC1083901 DOI: 10.1093/embo-reports/kve107] [Citation(s) in RCA: 39] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2000] [Revised: 03/12/2001] [Accepted: 04/10/2001] [Indexed: 11/13/2022] Open
Abstract
Thyroid hormone T3/T4 is a major regulator of energy metabolism in vertebrates, and defects in thyroid status are frequently associated with changes in body weight. It is demonstrated here that thyroid hormone regulates in vivo and in vitro the tub gene, which when mutated in tubby mice causes obesity, insulin resistance and sensory deficits. Hypothyroidism in rats altered tub mRNA and protein in discrete brain areas. These changes could be attributed to thyroid hormone deficiency since T3/T4 treatment restored normal tub expression. T3 also upregulated tub mRNA within 4-6 h in neuronal cells in culture, suggesting that T3 is a positive regulator of tub gene expression. Thus, these results establish a novel pathway of T3 action and provide an important molecular link between thyroid status and the tubby-associated syndrome.
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Affiliation(s)
- N P Koritschoner
- 1Max-Delbrück-Center for Molecular Medicine MDC, Robert-Rössle Strasse 10, D-13122 Berlin, Germany
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48
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Hacker C, Glinski M, Hornbogen T, Doller A, Zocher R. Mutational analysis of the N-methyltransferase domain of the multifunctional enzyme enniatin synthetase. J Biol Chem 2000; 275:30826-32. [PMID: 10887181 DOI: 10.1074/jbc.m002614200] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
N-Methylcyclopeptides like cyclosporins and enniatins are synthesized by multifunctional enzymes representing hybrid systems of peptide synthetases and S-adenosyl-l-methionine (AdoMet)-dependent N-methyltransferases. The latter constitute a new family of N-methyltransferases sharing high homology within procaryotes and eucaryotes. Here we describe the mutational analysis of the N-methyltransferase domain of enniatin synthetase from Fusarium scirpi to gain insight into the assembly of the AdoMet-binding site. The role of four conserved motifs (I, (2085)VLEIGTGSGMIL; II/Y, (2105)SYVGLDPS; IV, (2152)DLVVFNSVVQYFTPPEYL; and V, (2194)ATNGHFLAARA) in cofactor binding as measured by photolabeling was studied. Deletion of the first 21 N-terminal amino acid residues of the N-methyltransferase domain did not affect AdoMet binding. Further shortening close to motif I resulted in loss of binding activity. Truncation of 38 amino acids from the C terminus and also internal deletions containing motif V led to complete loss of AdoMet-binding activity. Point mutations converting the conserved Tyr(223) (corresponding to position 2106 in enniatin synthetase) in motif II/Y (close to motif I) into Val, Ala, and Ser, respectively, strongly diminished AdoMet binding, whereas conversion of this residue to Phe restored AdoMet-binding activity to approximately 70%, indicating that Tyr(223) is important for AdoMet binding and that the aromatic Tyr(223) may be crucial for AdoMet binding in N-methylpeptide synthetases.
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Affiliation(s)
- C Hacker
- Max-Volmer-Institut für Biophysikalische Chemie und Biochemie, Fachgebiet Biochemie und Molekulare Biologie, Technische Universität Berlin, Franklinstrasse 29, D-10587 Berlin, Germany
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Halleck MS, Lawler JF JR, Blackshaw S, Gao L, Nagarajan P, Hacker C, Pyle S, Newman JT, Nakanishi Y, Ando H, Weinstock D, Williamson P, Schlegel RA. Differential expression of putative transbilayer amphipath transporters. Physiol Genomics 1999; 1:139-50. [PMID: 11015572 DOI: 10.1152/physiolgenomics.1999.1.3.139] [Citation(s) in RCA: 62] [Impact Index Per Article: 2.5] [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] [Indexed: 11/22/2022] Open
Abstract
The aminophospholipid translocase transports phosphatidylserine and phosphatidylethanolamine from one side of a bilayer to another. Cloning of the gene encoding the enzyme identified a new subfamily of P-type ATPases, proposed to be amphipath transporters. As reported here, mammals express as many as 17 different genes from this subfamily. Phylogenetic analysis reveals the genes to be grouped into several distinct classes and subclasses. To gain information on the functions represented by these groups, Northern analysis and in situ hybridization were used to examine the pattern of expression of a panel of subfamily members in the mouse. The genes are differentially expressed in the respiratory, digestive, and urogenital systems, endocrine organs, the eye, teeth, and thymus. With one exception, all of the genes are highly expressed in the central nervous system (CNS); however, the pattern of expression within the CNS differs substantially from gene to gene. These results suggest that the genes are expressed in a tissue-specific manner, are not simply redundant, and may represent isoforms that transport a variety of different amphipaths.
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Affiliation(s)
- M S Halleck
- Department of Biochemistry and Molecular Biology, Penn State University, University Park, Pennsylvania 16802, USA
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Cascieri MA, Koch GE, Ber E, Sadowski SJ, Louizides D, de Laszlo SE, Hacker C, Hagmann WK, MacCoss M, Chicchi GG, Vicario PP. Characterization of a novel, non-peptidyl antagonist of the human glucagon receptor. J Biol Chem 1999; 274:8694-7. [PMID: 10085108 DOI: 10.1074/jbc.274.13.8694] [Citation(s) in RCA: 71] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
We have identified a series of potent, orally bioavailable, non-peptidyl, triarylimidazole and triarylpyrrole glucagon receptor antagonists. 2-(4-Pyridyl)-5-(4-chlorophenyl)-3-(5-bromo-2-propyloxyphenyl)p yrr ole (L-168,049), a prototypical member of this series, inhibits binding of labeled glucagon to the human glucagon receptor with an IC50 = 3. 7 +/- 3.4 nM (n = 7) but does not inhibit binding of labeled glucagon-like peptide to the highly homologous human glucagon-like peptide receptor at concentrations up to 10 microM. The binding affinity of L-168,049 for the human glucagon receptor is decreased 24-fold by the inclusion of divalent cations (5 mM). L-168,049 increases the apparent EC50 for glucagon stimulation of adenylyl cyclase in Chinese hamster ovary cells expressing the human glucagon receptor and decreases the maximal glucagon stimulation observed, with a Kb (concentration of antagonist that shifts the agonist dose-response 2-fold) of 25 nM. These data suggest that L-168,049 is a noncompetitive antagonist of glucagon action. Inclusion of L-168, 049 increases the rate of dissociation of labeled glucagon from the receptor 4-fold, confirming that the compound is a noncompetitive glucagon antagonist. In addition, we have identified two putative transmembrane domain residues, phenylalanine 184 in transmembrane domain 2 and tyrosine 239 in transmembrane domain 3, for which substitution by alanine reduces the affinity of L-168,049 46- and 4. 5-fold, respectively. These mutations do not alter the binding of labeled glucagon, suggesting that the binding sites for glucagon and L-168,049 are distinct.
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Affiliation(s)
- M A Cascieri
- Department of Molecular Pharmacology & Biochemistry, Merck Research Laboratories, Rahway, New Jersey 07065, USA.
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