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Saner S, Băzăvan O, Minder M, Drmota P, Webb DJ, Araneda G, Srinivas R, Lucas DM, Ballance CJ. Breaking the Entangling Gate Speed Limit for Trapped-Ion Qubits Using a Phase-Stable Standing Wave. Phys Rev Lett 2023; 131:220601. [PMID: 38101375 DOI: 10.1103/physrevlett.131.220601] [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] [Subscribe] [Scholar Register] [Received: 05/31/2023] [Accepted: 10/16/2023] [Indexed: 12/17/2023]
Abstract
All laser-driven entangling operations for trapped-ion qubits have hitherto been performed without control of the optical phase of the light field, which precludes independent tuning of the carrier and motional coupling. By placing ^{88}Sr^{+} ions in a λ=674 nm standing wave, whose relative position is controlled to ≈λ/100, we suppress the carrier coupling by a factor of 18, while coherently enhancing the spin-motion coupling. We experimentally demonstrate that the off-resonant carrier coupling imposes a speed limit for conventional traveling-wave Mølmer-Sørensen gates; we use the standing wave to surpass this limit and achieve a gate duration of 15 μs, restricted by the available laser power.
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Affiliation(s)
- S Saner
- Department of Physics, University of Oxford, Clarendon Laboratory, Parks Road, Oxford OX1 3PU, United Kingdom
| | - O Băzăvan
- Department of Physics, University of Oxford, Clarendon Laboratory, Parks Road, Oxford OX1 3PU, United Kingdom
| | - M Minder
- Department of Physics, University of Oxford, Clarendon Laboratory, Parks Road, Oxford OX1 3PU, United Kingdom
| | - P Drmota
- Department of Physics, University of Oxford, Clarendon Laboratory, Parks Road, Oxford OX1 3PU, United Kingdom
| | - D J Webb
- Department of Physics, University of Oxford, Clarendon Laboratory, Parks Road, Oxford OX1 3PU, United Kingdom
| | - G Araneda
- Department of Physics, University of Oxford, Clarendon Laboratory, Parks Road, Oxford OX1 3PU, United Kingdom
| | - R Srinivas
- Department of Physics, University of Oxford, Clarendon Laboratory, Parks Road, Oxford OX1 3PU, United Kingdom
| | - D M Lucas
- Department of Physics, University of Oxford, Clarendon Laboratory, Parks Road, Oxford OX1 3PU, United Kingdom
| | - C J Ballance
- Department of Physics, University of Oxford, Clarendon Laboratory, Parks Road, Oxford OX1 3PU, United Kingdom
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2
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Allsop T, Tahir MW, Bhavasar K, Zhang L, Webb DJ. Long-period gratings for monitoring the resin transfer molding of fiber-reinforced polymer composites. Opt Lett 2023; 48:3503-3506. [PMID: 37390166 DOI: 10.1364/ol.489885] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/22/2023] [Accepted: 05/20/2023] [Indexed: 07/02/2023]
Abstract
The spectral characteristics of long-period gratings (LPGs) have been researched over the last two decades, and many sensing applications of LPGs have been proposed due to their spectral sensitivity to many surrounding environmental parameters such as the temperature, pressure, and refractive index. However, this sensitivity to many parameters can also be a curse due to cross-sensitivity and the inability to distinguish which environmental parameter is responsible for the LPG's spectral behavior. For the application proposed here-monitoring the progress of a resin flow front, its velocity, and the permeability of the reinforcement mats during the infusion stage of resin transfer molding-the multi-sensitivity of LPGs is a distinct advantage, as it provides the ability to monitor the mold environment at various stages of manufacturing.
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Cherrie M, Clemens T, Colandrea C, Feng Z, Webb DJ, Weller RB, Dibben C. Ultraviolet A radiation and COVID-19 deaths in the USA with replication studies in England and Italy. Br J Dermatol 2021; 185:363-370. [PMID: 33834487 PMCID: PMC8251104 DOI: 10.1111/bjd.20093] [Citation(s) in RCA: 27] [Impact Index Per Article: 9.0] [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] [Accepted: 03/29/2021] [Indexed: 12/27/2022]
Abstract
Background Understanding factors impacting deaths from COVID‐19 is of the highest priority. Seasonal variation in environmental meteorological conditions affects the incidence of many infectious diseases and may also affect COVID‐19. Ultraviolet (UV) A (UVA) radiation induces release of cutaneous photolabile nitric oxide (NO) impacting the cardiovascular system and metabolic syndrome, both COVID‐19 risk factors. NO also inhibits the replication of SARS‐CoV2. Objectives To investigate the relationship between ambient UVA radiation and COVID‐19 deaths. Methods COVID‐19 deaths at the county level, across the USA, were modelled in a zero‐inflated negative‐binomial model with a random effect for states adjusting for confounding by demographic, socioeconomic and long‐term environmental variables. Only those areas where UVB was too low to induce significant cutaneous vitamin D3 synthesis were modelled. We used satellite‐derived estimates of UVA, UVB and temperature and relative humidity. Replication models were undertaken using comparable data for England and Italy. Results The mortality rate ratio (MRR) in the USA falls by 29% [95% confidence interval (CI) 40% to 15%) per 100 kJ m–2 increase in mean daily UVA. We replicated this in independent studies in Italy and England and estimate a pooled decline in MRR of 32% (95% CI 48% to 12%) per 100 kJ m–2 across the three studies. Conclusions Our analysis suggests that higher ambient UVA exposure is associated with lower COVID‐19‐specific mortality. Further research on the mechanism may indicate novel treatments. Optimized UVA exposure may have population health benefits.
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Affiliation(s)
- M Cherrie
- School of Geosciences, University of Edinburgh, Edinburgh, UK
| | - T Clemens
- School of Geosciences, University of Edinburgh, Edinburgh, UK
| | - C Colandrea
- School of Geosciences, University of Edinburgh, Edinburgh, UK
| | - Z Feng
- School of Geosciences, University of Edinburgh, Edinburgh, UK
| | - D J Webb
- Centre for Cardiovascular Science, University of Edinburgh, Edinburgh, UK
| | - R B Weller
- Centre for Inflammation Research, University of Edinburgh, Edinburgh, UK
| | - C Dibben
- School of Geosciences, University of Edinburgh, Edinburgh, UK
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Nielsen CP, Jernigan KK, Diggins NL, Webb DJ, MacGurn JA. USP9X Deubiquitylates DVL2 to Regulate WNT Pathway Specification. Cell Rep 2020; 28:1074-1089.e5. [PMID: 31340145 PMCID: PMC6884140 DOI: 10.1016/j.celrep.2019.06.083] [Citation(s) in RCA: 31] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2018] [Revised: 05/22/2019] [Accepted: 06/24/2019] [Indexed: 01/12/2023] Open
Abstract
The WNT signaling network is comprised of multiple receptors that relay various input signals via distinct transduction pathways to execute multiple complex and context-specific output processes. Integrity of the WNT signaling network relies on proper specification between canonical and noncanonical pathways, which presents a regulatory challenge given that several signal transducing elements are shared between pathways. Here, we report that USP9X, a deubiquitylase, and WWP1, an E3 ubiquitin ligase, regulate a ubiquitin rheostat on DVL2, a WNT signaling protein. Our findings indicate that USP9X-mediated deubiquitylation of DVL2 is required for canonical WNT activation, while increased DVL2 ubiquitylation is associated with localization to actin-rich projections and activation of the planar cell polarity (PCP) pathway. We propose that a WWP1-USP9X axis regulates a ubiquitin rheostat on DVL2 that specifies its participation in either canonical WNT or WNT-PCP pathways. These findings have important implications for therapeutic targeting of USP9X in human cancer. DVL2 is a signal transducing protein that participates in canonical and noncanonical WNT signaling relays. Here, Nielsen et al. report that the deubiquitylase USP9X and the E3 ubiquitin ligase WWP1 operate on DVL2 to establish a ubiquitin rheostat that contributes to WNT pathway specification in human breast cancer cells.
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Affiliation(s)
- Casey P Nielsen
- Department of Cell and Developmental Biology, Vanderbilt University, Nashville, TN 37240, USA
| | - Kristin K Jernigan
- Department of Cell and Developmental Biology, Vanderbilt University, Nashville, TN 37240, USA
| | - Nicole L Diggins
- Department of Biological Sciences, Vanderbilt University, Nashville, TN 37240, USA
| | - Donna J Webb
- Department of Biological Sciences, Vanderbilt University, Nashville, TN 37240, USA
| | - Jason A MacGurn
- Department of Cell and Developmental Biology, Vanderbilt University, Nashville, TN 37240, USA.
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Allsop T, Neal R, Kundrat V, Wang C, Mou C, Culverhouse P, Ania-Castanon JD, Kalli K, Webb DJ. Low-dimensional nano-patterned surface fabricated by direct-write UV-chemically induced geometric inscription technique. Opt Lett 2019; 44:195-198. [PMID: 30644859 DOI: 10.1364/ol.44.000195] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/24/2018] [Accepted: 11/27/2018] [Indexed: 06/09/2023]
Abstract
We investigate a nano-patterning process which creates reproducible periodic surface topological features that range in size from ∼100 μm to ∼20 μm. Specifically, we have fabricated multi-layered thin films consisting of germanium/silicon strata on a planar substrate, with each layer having nanometers thickness. The material processing exploits focused 244 nm ultra-violet laser light and an opto-mechanical setup typically applied to the inscription of fiber gratings, and is based upon the well-known material compaction interaction of ultra-violet light with germanium oxides. We show this process can be extended to create arrays of metal nano-antennas by adding a metal overlay to the thin film. This results in arrays with dimensions that span nanometer- to centimeter-length scales. Also, each nano-antenna consists of "nano-blocks." Experimental data are presented that show the UV irradiance dosage used to create these metal nanostructures on D-shaped optical fibers has a direct relationship to their transmission spectral characteristics as plasmonic devices.
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Chauhan A, Lalor T, Watson S, Adams D, Farrah TE, Anand A, Kimmitt R, Mills NL, Webb DJ, Dhaun N, Kalla R, Adams A, Vatn S, Bonfliglio F, Nimmo E, Kennedy N, Ventham N, Vatn M, Ricanek P, Halfvarson J, Soderhollm J, Pierik M, Torkvist L, Gomollon F, Gut I, Jahnsen J, Satsangi J, Body R, Almashali M, McDowell G, Taylor P, Lacey A, Rees A, Dayan C, Lazarus J, Nelson S, Okosieme O, Corcoran D, Young R, Ciadella P, McCartney P, Bajrangee A, Hennigan B, Collison D, Carrick D, Shaukat A, Good R, Watkins S, McEntegart M, Watt J, Welsh P, Sattar N, McConnachie A, Oldroyd K, Berry C, Parks T, Auckland K, Mentzer AJ, Kado J, Mirabel MM, Kauwe JK, Robson KJ, Mittal B, Steer AC, Hill AVS, Akbar M, Forrester M, Virlan AT, Gilmour A, Wallace C, Paterson C, Reid D, Siebert S, Porter D, Liversidge J, McInnes I, Goodyear C, Athwal V, Pritchett J, Zaitoun A, Irving W, Guha IN, Hanley NA, Hanley KP, Briggs T, Reynolds J, Rice G, Bondet V, Bruce E, Crow Y, Duffy D, Parker B, Bruce I, Martin K, Pritchett J, Aoibheann Mullan M, Llewellyn J, Athwal V, Zeef L, Farrow S, Streuli C, Henderson N, Friedman S, Hanley N, Hanley KP. Scientific Business Abstracts of the 112th Annual Meeting of the Association of Physicians of Great Britain and Ireland. QJM 2018; 111:920-924. [PMID: 31222346 DOI: 10.1093/qjmed/hcy193] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Affiliation(s)
| | - T Lalor
- From the University of Birmingham
| | - S Watson
- From the University of Birmingham
| | - D Adams
- From the University of Birmingham
| | - T E Farrah
- From the University/British Heart Foundation Centre of Research Excellence, University of Edinburgh
| | - A Anand
- From the University/British Heart Foundation Centre of Research Excellence, University of Edinburgh
| | - R Kimmitt
- From the University/British Heart Foundation Centre of Research Excellence, University of Edinburgh
| | - N L Mills
- From the University/British Heart Foundation Centre of Research Excellence, University of Edinburgh
| | - D J Webb
- From the University/British Heart Foundation Centre of Research Excellence, University of Edinburgh
| | - N Dhaun
- From the University/British Heart Foundation Centre of Research Excellence, University of Edinburgh
| | - R Kalla
- From the University of Edinburgh
| | - A Adams
- From the University of Edinburgh
| | - S Vatn
- Akerhshus University Hospital
| | | | - E Nimmo
- From the University of Edinburgh
| | | | | | | | | | | | | | - M Pierik
- Maastricht University Medical Centre
| | | | | | | | | | | | - R Body
- From the University of Manchester
| | - M Almashali
- Manchester University Hospitals Foundation NHS Trust
| | | | | | | | - A Rees
- From the Cardiff University
| | | | | | | | | | - D Corcoran
- From the British Heart Foundation (BHF), Glasgow Cardiovascular Research Centre, University of Glasgow
| | - R Young
- Robertson Centre for Biostatistics, University of Glasgow
| | - P Ciadella
- West of Scotland Heart and Lung Centre, Golden Jubilee National Hospital
| | - P McCartney
- From the British Heart Foundation (BHF), Glasgow Cardiovascular Research Centre, University of Glasgow
| | - A Bajrangee
- West of Scotland Heart and Lung Centre, Golden Jubilee National Hospital
| | - B Hennigan
- West of Scotland Heart and Lung Centre, Golden Jubilee National Hospital
| | - D Collison
- West of Scotland Heart and Lung Centre, Golden Jubilee National Hospital
| | - D Carrick
- West of Scotland Heart and Lung Centre, Golden Jubilee National Hospital
| | - A Shaukat
- West of Scotland Heart and Lung Centre, Golden Jubilee National Hospital
| | - R Good
- West of Scotland Heart and Lung Centre, Golden Jubilee National Hospital
| | - S Watkins
- West of Scotland Heart and Lung Centre, Golden Jubilee National Hospital
| | - M McEntegart
- West of Scotland Heart and Lung Centre, Golden Jubilee National Hospital
| | - J Watt
- West of Scotland Heart and Lung Centre, Golden Jubilee National Hospital
| | - P Welsh
- From the British Heart Foundation (BHF), Glasgow Cardiovascular Research Centre, University of Glasgow
| | - N Sattar
- From the British Heart Foundation (BHF), Glasgow Cardiovascular Research Centre, University of Glasgow
| | - A McConnachie
- Robertson Centre for Biostatistics, University of Glasgow
| | - K Oldroyd
- West of Scotland Heart and Lung Centre, Golden Jubilee National Hospital
| | - C Berry
- From the British Heart Foundation (BHF), Glasgow Cardiovascular Research Centre, University of Glasgow
| | - T Parks
- From the London School of Hygiene and Tropical Medicine
- University of Oxford
| | | | | | - J Kado
- Fiji Islands Ministry of Health and Medical Services
| | - M M Mirabel
- French National Institute of Health and Medical Research
| | | | | | - B Mittal
- Babasaheb Bhimrao Ambedkar University
| | - A C Steer
- Murdoch Children's Research Institute
| | | | - M Akbar
- From the Institute of Infection, Immunity & Inflammation, University of Glasgow
| | - M Forrester
- Division of Applied Medicine, School of Medicine and Dentistry, University of Aberdeen
| | - A T Virlan
- From the Institute of Infection, Immunity & Inflammation, University of Glasgow
| | - A Gilmour
- From the Institute of Infection, Immunity & Inflammation, University of Glasgow
| | - C Wallace
- Division of Applied Medicine, School of Medicine and Dentistry, University of Aberdeen
| | - C Paterson
- From the Institute of Infection, Immunity & Inflammation, University of Glasgow
| | - D Reid
- Division of Applied Medicine, School of Medicine and Dentistry, University of Aberdeen
| | - S Siebert
- From the Institute of Infection, Immunity & Inflammation, University of Glasgow
| | - D Porter
- From the Institute of Infection, Immunity & Inflammation, University of Glasgow
| | - J Liversidge
- Division of Applied Medicine, School of Medicine and Dentistry, University of Aberdeen
| | - I McInnes
- From the Institute of Infection, Immunity & Inflammation, University of Glasgow
| | - C Goodyear
- From the Institute of Infection, Immunity & Inflammation, University of Glasgow
| | - V Athwal
- From the Manchester University Foundation NHS Trust
- University of Manchester
| | | | | | | | | | - N A Hanley
- From the Manchester University Foundation NHS Trust
- University of Manchester
| | | | - T Briggs
- From the Manchester Centre of Genomic Medicine, University of Manchester
| | - J Reynolds
- Division of Musculoskeletal & Dermatological Sciences, University of Manchester
| | - G Rice
- From the Manchester Centre of Genomic Medicine, University of Manchester
| | - V Bondet
- Immunobiology of Dendritic Cells, Institut Pasteur
| | - E Bruce
- Division of Musculoskeletal & Dermatological Sciences, University of Manchester
| | - Y Crow
- Laboratory of Neurogenetics and Neuroinflammation, INSERM UMR1163, Institut Imagine
| | - D Duffy
- Immunobiology of Dendritic Cells, Institut Pasteur
| | - B Parker
- Division of Musculoskeletal & Dermatological Sciences, University of Manchester
| | - I Bruce
- Division of Musculoskeletal & Dermatological Sciences, University of Manchester
| | - K Martin
- From the University of Manchester
| | | | | | | | - V Athwal
- From the University of Manchester
| | - L Zeef
- From the University of Manchester
| | - S Farrow
- From the University of Manchester
- Respiratory Therapy Area, GlaxoSmithKline
| | | | | | | | - N Hanley
- From the University of Manchester
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Wang R, Shi M, Brewer B, Yang L, Zhang Y, Webb DJ, Li D, Xu YQ. Ultrasensitive Graphene Optoelectronic Probes for Recording Electrical Activities of Individual Synapses. Nano Lett 2018; 18:5702-5708. [PMID: 30063361 PMCID: PMC6519721 DOI: 10.1021/acs.nanolett.8b02298] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/19/2023]
Abstract
The complex neuronal circuitry connected by submicron synapses in our brain calls for technologies that can map neural networks with ultrahigh spatiotemporal resolution to decipher the underlying mechanisms for multiple aspects of neuroscience. Here we show that, through combining graphene transistor arrays with scanning photocurrent microscopy, we can detect the electrical activities of individual synapses of primary hippocampal neurons. Through measuring the local conductance change of graphene optoelectronic probes directly underneath neuronal processes, we are able to estimate millivolt extracellular potential variations of individual synapses during depolarization. The ultrafast nature of graphene photocurrent response allows for decoding of activity patterns of individual synapses with a sub-millisecond temporal resolution. This new neurotechnology provides promising potentials for recording of electrophysiological outcomes of individual synapses in neural networks.
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Affiliation(s)
- Rui Wang
- Department of Physics and Astronomy, Vanderbilt University, Nashville, TN 37212, USA
| | - Mingjian Shi
- Department of Biological Science and Vanderbilt Kennedy Center for Research on Human Development, Vanderbilt University, Nashville, TN 37212, USA
| | - Bryson Brewer
- Department of Mechanical Engineering, Vanderbilt University, Nashville, TN 37212, USA
| | - Lijie Yang
- Department of Mechanical Engineering, Vanderbilt University, Nashville, TN 37212, USA
| | - Yuchen Zhang
- Department of Electrical Engineering and Computer Science, Vanderbilt University, Nashville, TN 37212, USA
| | - Donna J. Webb
- Department of Biological Science and Vanderbilt Kennedy Center for Research on Human Development, Vanderbilt University, Nashville, TN 37212, USA
- Department of Cancer Biology, Vanderbilt University, Nashville, TN 37212, USA
| | - Deyu Li
- Department of Mechanical Engineering, Vanderbilt University, Nashville, TN 37212, USA
- Correspondence to: and
| | - Ya-Qiong Xu
- Department of Physics and Astronomy, Vanderbilt University, Nashville, TN 37212, USA
- Department of Electrical Engineering and Computer Science, Vanderbilt University, Nashville, TN 37212, USA
- Correspondence to: and
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8
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Ivanović MD, Petrovic J, Savić A, Gligorić G, Miletić M, Vukčević M, Bojović B, Hadžievski L, Allsop T, Webb DJ. Real-time chest-wall-motion tracking by a single optical fibre grating: a prospective method for ventilator triggering. Physiol Meas 2018; 39:045009. [PMID: 29553480 DOI: 10.1088/1361-6579/aab7ac] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
OBJECTIVE The ventilators involved in non-invasive mechanical ventilation commonly provide ventilator support via a facemask. The interface of the mask with a patient promotes air leaks that cause errors in the feedback information provided by a pneumatic sensor and hence patient-ventilator asynchrony with multiple negative consequences. Our objective is to test the possibility of using chest-wall motion measured by an optical fibre-grating sensor as a more accurate non-invasive ventilator triggering mechanism. APPROACH The basic premise of our approach is that the measurement accuracy can be improved by using a triggering signal that precedes pneumatic triggering in the neuro-ventilatory coupling sequence. We propose a technique that uses the measurement of chest-wall curvature by a long-period fibre-grating sensor. The sensor was applied externally to the rib-cage and interrogated in the lateral (edge) filtering scheme. The study was performed on 34 healthy volunteers. Statistical data analysis of the time lag between the fibre-grating sensor and the reference pneumotachograph was preceded by the removal of the unwanted heartbeat signal by wavelet transform processing. MAIN RESULTS The results show a consistent fibre-grating signal advance with respect to the standard pneumatic signal by (230 ± 100) ms in both the inspiratory and expiratory phases. We further show that heart activity removal yields a tremendous improvement in sensor accuracy by reducing it from 60 ml to 0.3 ml. SIGNIFICANCE The results indicate that the proposed measurement technique may lead to a more reliable triggering decision. Its imperviousness to air leaks, non-invasiveness, low-cost and ease of implementation offer good prospects for applications in both clinical and homecare ventilation.
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Affiliation(s)
- M D Ivanović
- Vinča Institute of Nuclear Sciences, University of Belgrade, Mike Petrovića Alasa 12-14, 11001 Belgrade, Serbia
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9
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Diggins NL, Kang H, Weaver A, Webb DJ. α5β1 integrin trafficking and Rac activation are regulated by APPL1 in a Rab5-dependent manner to inhibit cell migration. J Cell Sci 2018; 131:jcs.207019. [PMID: 29361527 DOI: 10.1242/jcs.207019] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2017] [Accepted: 01/09/2018] [Indexed: 01/04/2023] Open
Abstract
Cell migration is a tightly coordinated process that requires the spatiotemporal regulation of many molecular components. Because adaptor proteins can serve as integrators of cellular events, they are being increasingly studied as regulators of cell migration. The adaptor protein containing a pleckstrin-homology (PH) domain, phosphotyrosine binding (PTB) domain, and leucine zipper motif 1 (APPL1) is a 709 amino acid endosomal protein that plays a role in cell proliferation and survival as well as endosomal trafficking and signaling. However, its function in regulating cell migration is poorly understood. Here, we show that APPL1 hinders cell migration by modulating both trafficking and signaling events controlled by Rab5 in cancer cells. APPL1 decreases internalization and increases recycling of α5β1 integrin, leading to higher levels of α5β1 integrin at the cell surface that hinder adhesion dynamics. Furthermore, APPL1 decreases the activity of the GTPase Rac and its effector PAK, which in turn regulate cell migration. Thus, we demonstrate a novel role for the interaction between APPL1 and Rab5 in governing crosstalk between signaling and trafficking pathways on endosomes to affect cancer cell migration.This article has an associated First Person interview with the first author of the paper.
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Affiliation(s)
- Nicole L Diggins
- Department of Biological Sciences, Vanderbilt University, Nashville, TN 37232, USA
| | - Hakmook Kang
- Department of Biostatistics, Vanderbilt University School of Medicine, Nashville, TN 37232, USA
| | - Alissa Weaver
- Department of Cell and Developmental Biology, Vanderbilt University School of Medicine, Nashville, TN 37232, USA.,Department of Pathology, Microbiology, and Immunology, Vanderbilt University Medical Center, Nashville, TN 37232, USA.,Department of Cancer Biology, Vanderbilt University School of Medicine, Nashville, TN 37232, USA
| | - Donna J Webb
- Department of Biological Sciences, Vanderbilt University, Nashville, TN 37232, USA.,Department of Cancer Biology, Vanderbilt University School of Medicine, Nashville, TN 37232, USA.,Vanderbilt Kennedy Center, Vanderbilt University Medical Center, Nashville, TN 37232, USA
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10
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Pospori A, Marques CAF, Sagias G, Lamela-Rivera H, Webb DJ. Novel thermal annealing methodology for permanent tuning polymer optical fiber Bragg gratings to longer wavelengths. Opt Express 2018; 26:1411-1421. [PMID: 29402015 DOI: 10.1364/oe.26.001411] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/06/2017] [Accepted: 12/29/2017] [Indexed: 06/07/2023]
Abstract
The Bragg wavelength of a polymer optical fiber Bragg grating can be permanently shifted by utilizing the thermal annealing method. In all the reported fiber annealing cases, the authors were able to tune the Bragg wavelength only to shorter wavelengths, since the polymer fiber shrinks in length during the annealing process. This article demonstrates a novel thermal annealing methodology for permanently tuning polymer optical fiber Bragg gratings to any desirable spectral position, including longer wavelengths. Stretching the polymer optical fiber during the annealing process, the period of Bragg grating, which is directly related with the Bragg wavelength, can become permanently longer. The methodology presented in this article can be used to multiplex polymer optical fiber Bragg gratings at any desirable spectral position utilizing only one phase-mask for their photo-inscription, reducing thus their fabrication cost in an industrial setting.
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11
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Erdogan B, Ao M, White LM, Means AL, Brewer BM, Yang L, Washington MK, Shi C, Franco OE, Weaver AM, Hayward SW, Li D, Webb DJ. Cancer-associated fibroblasts promote directional cancer cell migration by aligning fibronectin. J Cell Biol 2017; 216:3799-3816. [PMID: 29021221 PMCID: PMC5674895 DOI: 10.1083/jcb.201704053] [Citation(s) in RCA: 349] [Impact Index Per Article: 49.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2017] [Revised: 08/31/2017] [Accepted: 09/25/2017] [Indexed: 02/08/2023] Open
Abstract
Cancer-associated fibroblasts (CAFs) are major components of the carcinoma microenvironment that promote tumor progression. However, the mechanisms by which CAFs regulate cancer cell migration are poorly understood. In this study, we show that fibronectin (Fn) assembled by CAFs mediates CAF-cancer cell association and directional migration. Compared with normal fibroblasts, CAFs produce an Fn-rich extracellular matrix with anisotropic fiber orientation, which guides the cancer cells to migrate directionally. CAFs align the Fn matrix by increasing nonmuscle myosin II- and platelet-derived growth factor receptor α-mediated contractility and traction forces, which are transduced to Fn through α5β1 integrin. We further show that prostate cancer cells use αv integrin to migrate efficiently and directionally on CAF-derived matrices. We demonstrate that aligned Fn is a prominent feature of invasion sites in human prostatic and pancreatic carcinoma samples. Collectively, we present a new mechanism by which CAFs organize the Fn matrix and promote directional cancer cell migration.
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Affiliation(s)
- Begum Erdogan
- Department of Biological Sciences, Vanderbilt University, Nashville, TN
| | - Mingfang Ao
- Department of Biological Sciences, Vanderbilt University, Nashville, TN
| | - Lauren M White
- Department of Biological Sciences, Vanderbilt University, Nashville, TN
| | - Anna L Means
- Department of Surgery, Vanderbilt University, Nashville, TN
- Department of Cell and Developmental Biology, Vanderbilt University, Nashville, TN
| | - Bryson M Brewer
- Department of Mechanical Engineering, Vanderbilt University, Nashville, TN
| | - Lijie Yang
- Department of Mechanical Engineering, Vanderbilt University, Nashville, TN
| | - M Kay Washington
- Department of Pathology, Microbiology and Immunology, Vanderbilt University, Nashville, TN
| | - Chanjuan Shi
- Department of Pathology, Microbiology and Immunology, Vanderbilt University, Nashville, TN
| | - Omar E Franco
- Department of Urologic Surgery, Vanderbilt University, Nashville, TN
- Department of Surgery, NorthShore University HealthSystem, Evanston, IL
| | - Alissa M Weaver
- Department of Cell and Developmental Biology, Vanderbilt University, Nashville, TN
- Department of Pathology, Microbiology and Immunology, Vanderbilt University, Nashville, TN
- Department of Cancer Biology, Vanderbilt University, Nashville, TN
| | - Simon W Hayward
- Department of Urologic Surgery, Vanderbilt University, Nashville, TN
- Department of Cancer Biology, Vanderbilt University, Nashville, TN
- Department of Surgery, NorthShore University HealthSystem, Evanston, IL
| | - Deyu Li
- Department of Mechanical Engineering, Vanderbilt University, Nashville, TN
| | - Donna J Webb
- Department of Biological Sciences, Vanderbilt University, Nashville, TN
- Department of Cancer Biology, Vanderbilt University, Nashville, TN
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12
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Pospori A, Marques CAF, Bang O, Webb DJ, André P. Polymer optical fiber Bragg grating inscription with a single UV laser pulse. Opt Express 2017; 25:9028-9038. [PMID: 28437977 DOI: 10.1364/oe.25.009028] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
We experimentally demonstrate the first polymer optical fiber Bragg grating inscribed with only one krypton fluoride laser pulse. The device has been recorded in a single-mode poly(methyl methacrylate) optical fiber, with a core doped with benzyl dimethyl ketal for photosensitivity enhancement. One laser pulse with a duration of 15 ns, which provide energy density of 974 mJ/cm2, is adequate to introduce a refractive index change of 0.74×10-4 in the fiber core. After the exposure, the reflectivity of the grating increases for a few minutes following a second order exponential saturation. The produced Bragg grating structure rejects 17.9 dB transmitted power, thus providing 98.4% reflectivity, which is well suited for sensing applications. In addition, we report the importance of the fiber thermal treatment before or after the inscription, showing its effects on the lifetime and quality of the grating structures. Optimizing the irradiation conditions and the material chemical composition, a higher refractive index change in the fiber core is feasible. This demonstration significantly improves the potential for commercial exploitation of the technology.
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13
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Allsop T, Mou C, Neal R, Mariani S, Nagel D, Tombelli S, Poole A, Kalli K, Hine A, Webb DJ, Culverhouse P, Mascini M, Minunni M, Bennion I. Real-time kinetic binding studies at attomolar concentrations in solution phase using a single-stage opto-biosensing platform based upon infrared surface plasmons. Opt Express 2017; 25:39-58. [PMID: 28085810 DOI: 10.1364/oe.25.000039] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
Here we present a new generic opto-bio-sensing platform combining immobilised aptamers on an infrared plasmonic sensing device generated by nano-structured thin film that demonstrates amongst the highest index spectral sensitivities of any optical fibre sensor yielding on average 3.4 × 104 nm/RIU in the aqueous index regime (with a figure of merit of 330) This offers a single stage, solution phase, atto-molar detection capability, whilst delivering real-time data for kinetic studies in water-based chemistry. The sensing platform is based upon optical fibre and has the potential to be multiplexed and used in remote sensing applications. As an example of the highly versatile capabilities of aptamer based detection using our platform, purified thrombin is detected down to 50 attomolar concentration using a volume of 1mm3 of solution without the use of any form of enhancement technique. Moreover, the device can detect nanomolar levels of thrombin in a flow cell, in the presence of 4.5% w/v albumin solution. These results are important, covering all concentrations in the human thrombin generation curve, including the problematic initial phase. Finally, selectivity is confirmed using complementary and non-complementary DNA sequences that yield performances similar to those obtained with thrombin.
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14
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15
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Brown JA, Codreanu SG, Shi M, Sherrod SD, Markov DA, Neely MD, Britt CM, Hoilett OS, Reiserer RS, Samson PC, McCawley LJ, Webb DJ, Bowman AB, McLean JA, Wikswo JP. Metabolic consequences of inflammatory disruption of the blood-brain barrier in an organ-on-chip model of the human neurovascular unit. J Neuroinflammation 2016; 13:306. [PMID: 27955696 PMCID: PMC5153753 DOI: 10.1186/s12974-016-0760-y] [Citation(s) in RCA: 108] [Impact Index Per Article: 13.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2016] [Accepted: 11/07/2016] [Indexed: 11/24/2022] Open
Abstract
Background Understanding blood-brain barrier responses to inflammatory stimulation (such as lipopolysaccharide mimicking a systemic infection or a cytokine cocktail that could be the result of local or systemic inflammation) is essential to understanding the effect of inflammatory stimulation on the brain. It is through the filter of the blood-brain barrier that the brain responds to outside influences, and the blood-brain barrier is a critical point of failure in neuroinflammation. It is important to note that this interaction is not a static response, but one that evolves over time. While current models have provided invaluable information regarding the interaction between cytokine stimulation, the blood-brain barrier, and the brain, these approaches—whether in vivo or in vitro—have often been only snapshots of this complex web of interactions. Methods We utilize new advances in microfluidics, organs-on-chips, and metabolomics to examine the complex relationship of inflammation and its effects on blood-brain barrier function ex vivo and the metabolic consequences of these responses and repair mechanisms. In this study, we pair a novel dual-chamber, organ-on-chip microfluidic device, the NeuroVascular Unit, with small-volume cytokine detection and mass spectrometry analysis to investigate how the blood-brain barrier responds to two different but overlapping drivers of neuroinflammation, lipopolysaccharide and a cytokine cocktail of IL-1β, TNF-α, and MCP1,2. Results In this study, we show that (1) during initial exposure to lipopolysaccharide, the blood-brain barrier is compromised as expected, with increased diffusion and reduced presence of tight junctions, but that over time, the barrier is capable of at least partial recovery; (2) a cytokine cocktail also contributes to a loss of barrier function; (3) from this time-dependent cytokine activation, metabolic signature profiles can be obtained for both the brain and vascular sides of the blood-brain barrier model; and (4) collectively, we can use metabolite analysis to identify critical pathways in inflammatory response. Conclusions Taken together, these findings present new data that allow us to study the initial effects of inflammatory stimulation on blood-brain barrier disruption, cytokine activation, and metabolic pathway changes that drive the response and recovery of the barrier during continued inflammatory exposure. Electronic supplementary material The online version of this article (doi:10.1186/s12974-016-0760-y) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Jacquelyn A Brown
- Department of Physics and Astronomy, Vanderbilt University, Nashville, TN, 37235, USA.,Vanderbilt Institute for Integrative Biosystems Research and Education, Vanderbilt University, 6301 Stevenson Center, Nashville, TN, 37235, USA
| | - Simona G Codreanu
- Department of Chemistry, Vanderbilt University, Nashville, TN, 37235, USA.,Center for Innovative Technology, Vanderbilt University, Nashville, TN, 37235, USA
| | - Mingjian Shi
- Department of Biological Sciences, Vanderbilt University, Nashville, TN, 37235, USA
| | - Stacy D Sherrod
- Vanderbilt Institute for Integrative Biosystems Research and Education, Vanderbilt University, 6301 Stevenson Center, Nashville, TN, 37235, USA.,Department of Chemistry, Vanderbilt University, Nashville, TN, 37235, USA.,Center for Innovative Technology, Vanderbilt University, Nashville, TN, 37235, USA.,Vanderbilt Institute of Chemical Biology, Vanderbilt University, Nashville, TN, 37232, USA
| | - Dmitry A Markov
- Vanderbilt Institute for Integrative Biosystems Research and Education, Vanderbilt University, 6301 Stevenson Center, Nashville, TN, 37235, USA.,Department of Biomedical Engineering, Vanderbilt University, Nashville, TN, 37235, USA
| | - M Diana Neely
- Department of Pediatrics, Vanderbilt University Medical Center, Nashville, TN, 37232, USA.,Vanderbilt Kennedy Center, Vanderbilt University Medical Center, Nashville, TN, 37203, USA.,Vanderbilt Brain Institute, Vanderbilt University, Nashville, TN, 37232, USA
| | - Clayton M Britt
- Department of Physics and Astronomy, Vanderbilt University, Nashville, TN, 37235, USA.,Vanderbilt Institute for Integrative Biosystems Research and Education, Vanderbilt University, 6301 Stevenson Center, Nashville, TN, 37235, USA
| | - Orlando S Hoilett
- Vanderbilt Institute for Integrative Biosystems Research and Education, Vanderbilt University, 6301 Stevenson Center, Nashville, TN, 37235, USA
| | - Ronald S Reiserer
- Department of Physics and Astronomy, Vanderbilt University, Nashville, TN, 37235, USA.,Vanderbilt Institute for Integrative Biosystems Research and Education, Vanderbilt University, 6301 Stevenson Center, Nashville, TN, 37235, USA
| | - Philip C Samson
- Department of Physics and Astronomy, Vanderbilt University, Nashville, TN, 37235, USA.,Vanderbilt Institute for Integrative Biosystems Research and Education, Vanderbilt University, 6301 Stevenson Center, Nashville, TN, 37235, USA
| | - Lisa J McCawley
- Vanderbilt Institute for Integrative Biosystems Research and Education, Vanderbilt University, 6301 Stevenson Center, Nashville, TN, 37235, USA.,Department of Biomedical Engineering, Vanderbilt University, Nashville, TN, 37235, USA.,Department of Cancer Biology, Vanderbilt University, Nashville, TN, 37232, USA
| | - Donna J Webb
- Vanderbilt Institute for Integrative Biosystems Research and Education, Vanderbilt University, 6301 Stevenson Center, Nashville, TN, 37235, USA.,Department of Biological Sciences, Vanderbilt University, Nashville, TN, 37235, USA
| | - Aaron B Bowman
- Department of Pediatrics, Vanderbilt University Medical Center, Nashville, TN, 37232, USA.,Vanderbilt Kennedy Center, Vanderbilt University Medical Center, Nashville, TN, 37203, USA.,Vanderbilt Brain Institute, Vanderbilt University, Nashville, TN, 37232, USA.,Department of Neurology, Vanderbilt University Medical Center, Nashville, TN, 37232, USA.,Department of Biochemistry, Vanderbilt University, Nashville, TN, 37232, USA
| | - John A McLean
- Vanderbilt Institute for Integrative Biosystems Research and Education, Vanderbilt University, 6301 Stevenson Center, Nashville, TN, 37235, USA.,Department of Chemistry, Vanderbilt University, Nashville, TN, 37235, USA.,Center for Innovative Technology, Vanderbilt University, Nashville, TN, 37235, USA.,Vanderbilt Institute of Chemical Biology, Vanderbilt University, Nashville, TN, 37232, USA
| | - John P Wikswo
- Department of Physics and Astronomy, Vanderbilt University, Nashville, TN, 37235, USA. .,Vanderbilt Institute for Integrative Biosystems Research and Education, Vanderbilt University, 6301 Stevenson Center, Nashville, TN, 37235, USA. .,Department of Biomedical Engineering, Vanderbilt University, Nashville, TN, 37235, USA. .,Department of Molecular Physiology and Biophysics, Vanderbilt University, Nashville, TN, 37232, USA.
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16
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Yang L, Carrington LJ, Erdogan B, Ao M, Brewer BM, Webb DJ, Li D. Biomechanics of cell reorientation in a three-dimensional matrix under compression. Exp Cell Res 2016; 350:253-266. [PMID: 27919745 DOI: 10.1016/j.yexcr.2016.12.002] [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] [Received: 09/27/2016] [Revised: 11/30/2016] [Accepted: 12/01/2016] [Indexed: 01/02/2023]
Abstract
Although a number of studies have reported that cells cultured on a stretchable substrate align away from or perpendicular to the stretch direction, how cells sense and respond to compression in a three-dimensional (3D) matrix remains an open question. We analyzed the reorientation of human prostatic normal tissue fibroblasts (NAFs) and cancer-associated fibroblasts (CAFs) in response to 3D compression using a Fast Fourier Transform (FFT) method. Results show that NAFs align to specific angles upon compression while CAFs exhibit a random distribution. In addition, NAFs with enhanced contractile force induced by transforming growth factor β (TGF-β) behave in a similar way as CAFs. Furthermore, a theoretical model based on the minimum energy principle has been developed to provide insights into these observations. The model prediction is in agreement with the observed cell orientation patterns in several different experimental conditions, disclosing the important role of stress fibers and inherent cell contractility in cell reorientation.
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Affiliation(s)
- Lijie Yang
- Department of Mechanical Engineering, Vanderbilt University, Nashville 37235, TN, USA
| | - Léolène Jean Carrington
- Department of Biological Sciences and Vanderbilt Kennedy Center for Research on Human Development, Vanderbilt University, Nashville 37235, TN, USA
| | - Begum Erdogan
- Department of Biological Sciences and Vanderbilt Kennedy Center for Research on Human Development, Vanderbilt University, Nashville 37235, TN, USA
| | - Mingfang Ao
- Department of Biological Sciences and Vanderbilt Kennedy Center for Research on Human Development, Vanderbilt University, Nashville 37235, TN, USA
| | - Bryson M Brewer
- Department of Mechanical Engineering, Vanderbilt University, Nashville 37235, TN, USA
| | - Donna J Webb
- Department of Biological Sciences and Vanderbilt Kennedy Center for Research on Human Development, Vanderbilt University, Nashville 37235, TN, USA.
| | - Deyu Li
- Department of Mechanical Engineering, Vanderbilt University, Nashville 37235, TN, USA.
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17
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Vliegenthart A, Kimmitt RA, Seymour JH, Homer NZ, Clarke JI, Eddleston M, Gray A, Wood DM, Dargan PI, Cooper JG, Antoine DJ, Webb DJ, Lewis SC, Bateman DN, Dear JW. Circulating acetaminophen metabolites are toxicokinetic biomarkers of acute liver injury. Clin Pharmacol Ther 2016; 101:531-540. [PMID: 27770431 PMCID: PMC6099202 DOI: 10.1002/cpt.541] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [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: 06/27/2016] [Revised: 09/15/2016] [Accepted: 10/17/2016] [Indexed: 02/07/2023]
Abstract
Acetaminophen (paracetamol-APAP) is the most common cause of drug-induced liver injury in the Western world. Reactive metabolite production by cytochrome P450 enzymes (CYP-metabolites) causes hepatotoxicity. We explored the toxicokinetics of human circulating APAP metabolites following overdose. Plasma from patients treated with acetylcysteine (NAC) for a single APAP overdose was analyzed from discovery (n = 116) and validation (n = 150) patient cohorts. In the discovery cohort, patients who developed acute liver injury (ALI) had higher CYP-metabolites than those without ALI. Receiver operator curve (ROC) analysis demonstrated that at hospital presentation CYP-metabolites were more sensitive/specific for ALI than alanine aminotransferase (ALT) activity and APAP concentration (optimal CYP-metabolite receiver operating characteristic area under the curve (ROC-AUC): 0.91 (95% confidence interval (CI) 0.83-0.98); ALT ROC-AUC: 0.67 (0.50-0.84); APAP ROC-AUC: 0.50 (0.33-0.67)). This enhanced sensitivity/specificity was replicated in the validation cohort. Circulating CYP-metabolites stratify patients by risk of liver injury prior to starting NAC. With development, APAP metabolites have potential utility in stratified trials and for refinement of clinical decision-making.
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Affiliation(s)
- Adb Vliegenthart
- Pharmacology, Toxicology and Therapeutics, University/BHF Centre for Cardiovascular Science, University of Edinburgh, UK
| | - R A Kimmitt
- Pharmacology, Toxicology and Therapeutics, University/BHF Centre for Cardiovascular Science, University of Edinburgh, UK
| | - J H Seymour
- Pharmacology, Toxicology and Therapeutics, University/BHF Centre for Cardiovascular Science, University of Edinburgh, UK
| | - N Z Homer
- Pharmacology, Toxicology and Therapeutics, University/BHF Centre for Cardiovascular Science, University of Edinburgh, UK
| | - J I Clarke
- MRC Centre for Drug Safety Science, Department of Molecular & Clinical Pharmacology, Institute of Translational Medicine, University of Liverpool, Liverpool, UK
| | - M Eddleston
- Pharmacology, Toxicology and Therapeutics, University/BHF Centre for Cardiovascular Science, University of Edinburgh, UK
| | - A Gray
- Emergency Medicine Research Group, Department of Emergency Medicine, Royal Infirmary of Edinburgh, Edinburgh, UK
| | - D M Wood
- Clinical Toxicology, Guy's and St Thomas' NHS Foundation Trust, London, UK.,King's College London, London, UK
| | - P I Dargan
- Clinical Toxicology, Guy's and St Thomas' NHS Foundation Trust, London, UK.,King's College London, London, UK
| | - J G Cooper
- Emergency Department, Aberdeen Royal Infirmary, Aberdeen, UK
| | - D J Antoine
- MRC Centre for Drug Safety Science, Department of Molecular & Clinical Pharmacology, Institute of Translational Medicine, University of Liverpool, Liverpool, UK
| | - D J Webb
- Pharmacology, Toxicology and Therapeutics, University/BHF Centre for Cardiovascular Science, University of Edinburgh, UK
| | - S C Lewis
- Centre for Population Health Sciences, University of Edinburgh, Edinburgh, UK
| | - D N Bateman
- Pharmacology, Toxicology and Therapeutics, University/BHF Centre for Cardiovascular Science, University of Edinburgh, UK
| | - J W Dear
- Pharmacology, Toxicology and Therapeutics, University/BHF Centre for Cardiovascular Science, University of Edinburgh, UK
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18
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Dear J, O'Dowd C, Timoney A, Paterson KR, Walker A, Webb DJ. Scottish Medicines Consortium: an Overview of Rapid New Drug Assessment in Scotland. Scott Med J 2016; 52:20-6. [PMID: 17874711 DOI: 10.1258/rsmsmj.52.3.20] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Affiliation(s)
- J Dear
- Clinical Pharmacology, University of Edinburgh
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19
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Abstract
Background and Aims: To assess physician opinion of, and attitudes to, the Scottish Intercollegiate Guideline Network (SIGN) guideline for chronic heart failure (CHF) due to left ventricular systolic dysfunction. Methods and Results: A questionnaire examining physicians' attitudes and their use of the SIGN guideline for CHF was distributed to 158 physicians in two teaching hospitals within one NHS trust. 65% of recipients responded. More cardiologists had read the guideline compared to non-cardiologists (91 vs 56%, p < 0.05). The majority of cardiologists and non-cardiologists agreed that it was applicable to their patients (92 vs 79%, p > 0.1) and that implementation may reduce hospital admissions (65 vs 59%, p > 0.5). In general, compliance was thought to be a problem in only a minority of patients in both groups for angiotensin converting enzyme inhibitors (8 vs 19%), diuretics (12 vs 29%) and digoxin (17 vs 19%, all p > 0.1). Beta-blocker compliance was identified as a problem by both groups (50 vs 53%, p > 0.5) while fewer cardiologists reported compliance as a problem with spironolactone (4 vs 25%, p < 0.05). More cardiologists felt that there was a need for a community based CHF nurse specialist (100 vs 57%, p < 0.001), and that this strategy would reduce hospital admissions (92 vs 57%, p < 0.01). Conclusions: Differences exist between cardiologist and non-cardiologist physicians' awareness of the SIGN guideline for CHF. Furthermore, we have shown differences in reported implementation of the guideline and perceived difficulties with specific drug therapies. This is in spite of high levels of agreement in both groups with the treatment suggested by the guideline and the anticipated benefits resulting from its implementation.
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Affiliation(s)
- S P McKee
- Cardiology Unit, Department of Medical Sciences, The University of Edinburgh, Western General Hospital, Edinburgh
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20
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Abstract
Dendritic spines and synapses are critical for neuronal communication, and they are perturbed in many neurological disorders; however, the study of these structures in living cells has been hindered by their small size. Super resolution microscopy, unlike conventional light microscopy, is diffraction unlimited and thus is well suited for imaging small structures, such as dendritic spines and synapses. Super resolution microscopy has already revealed important new information about spine and synapse morphology, actin remodeling, and nanodomain composition in both healthy cells and diseased states. In this review, we highlight the advancements in probes that make super resolution more amenable to live-cell imaging of spines and synapses. We also discuss recent data obtained by super resolution microscopy that has advanced our knowledge of dendritic spine and synapse structure, organization, and dynamics in both healthy and diseased contexts. Finally, we propose a series of critical questions for understanding spine and synapse formation and maturation that super resolution microscopy is poised to answer.
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Affiliation(s)
- Cristina M Robinson
- Department of Biological Sciences, Vanderbilt University, Nashville, Tennessee, USA
| | - Mikin R Patel
- Department of Biological Sciences, Vanderbilt University, Nashville, Tennessee, USA
| | - Donna J Webb
- Department of Biological Sciences, Vanderbilt University, Nashville, Tennessee, USA; Vanderbilt Kennedy Center for Research on Human Development, Vanderbilt University, Nashville, Tennessee, USA; Department of Cancer Biology, Vanderbilt University, Nashville, Tennessee, USA
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21
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Jean L, Yang L, Majumdar D, Gao Y, Shi M, Brewer BM, Li D, Webb DJ. The Rho family GEF Asef2 regulates cell migration in three dimensional (3D) collagen matrices through myosin II. Cell Adh Migr 2015; 8:460-7. [PMID: 25517435 DOI: 10.4161/19336918.2014.983778] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
Abstract
Cell migration is fundamental to a variety of physiological processes, including tissue development, homeostasis, and regeneration. Migration has been extensively studied with cells on 2-dimensional (2D) substrates, but much less is known about cell migration in 3D environments. Tissues and organs are 3D, which is the native environment of cells in vivo, pointing to a need to understand migration and the mechanisms that regulate it in 3D environments. To investigate cell migration in 3D environments, we developed microfluidic devices that afford a controlled, reproducible platform for generating 3D matrices. Using these devices, we show that the Rho family guanine nucleotide exchange factor (GEF) Asef2 inhibits cell migration in 3D type I collagen (collagen I) matrices. Treatment of cells with the myosin II (MyoII) inhibitor blebbistatin abolished the decrease in migration by Asef2. Moreover, Asef2 enhanced MyoII activity as shown by increased phosphorylation of serine 19 (S19). Furthermore, Asef2 increased activation of Rac, which is a Rho family small GTPase, in 3D collagen I matrices. Inhibition of Rac activity by treatment with the Rac-specific inhibitor NSC23766 abrogated the Asef2-promoted increase in S19 MyoII phosphorylation. Thus, our results indicate that Asef2 regulates cell migration in 3D collagen I matrices through a Rac-MyoII-dependent mechanism.
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Key Words
- 2D, 2-dimensional
- 3D, 3-dimensional
- Collagen I, type I collagen
- DMEM, Dulbecco's Modified Eagle Medium
- ECM, extracellular matrix
- GEF, guanine nucleotide exchange factor
- MyoII, non-muscle myosin II
- PAK, p21-activated kinase
- PBD, p21-binding domain
- PBS, phosphate buffer saline
- PDMS, polydimethylsiloxane
- Rac
- Rho family GTPases
- UV, ultra-violet
- guanine nucleotide exchange factor
- microfluidics
- myosin II
- type I collagen
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Affiliation(s)
- Léolène Jean
- a Department of Biological Sciences and Vanderbilt Kennedy Center for Research on Human Development ; Vanderbilt University ; Nashville , TN USA
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22
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Brown JA, Pensabene V, Markov DA, Allwardt V, Neely MD, Shi M, Britt CM, Hoilett OS, Yang Q, Brewer BM, Samson PC, McCawley LJ, May JM, Webb DJ, Li D, Bowman AB, Reiserer RS, Wikswo JP. Recreating blood-brain barrier physiology and structure on chip: A novel neurovascular microfluidic bioreactor. Biomicrofluidics 2015; 9:054124. [PMID: 26576206 PMCID: PMC4627929 DOI: 10.1063/1.4934713] [Citation(s) in RCA: 268] [Impact Index Per Article: 29.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/24/2015] [Accepted: 10/10/2015] [Indexed: 05/04/2023]
Abstract
The blood-brain barrier (BBB) is a critical structure that serves as the gatekeeper between the central nervous system and the rest of the body. It is the responsibility of the BBB to facilitate the entry of required nutrients into the brain and to exclude potentially harmful compounds; however, this complex structure has remained difficult to model faithfully in vitro. Accurate in vitro models are necessary for understanding how the BBB forms and functions, as well as for evaluating drug and toxin penetration across the barrier. Many previous models have failed to support all the cell types involved in the BBB formation and/or lacked the flow-created shear forces needed for mature tight junction formation. To address these issues and to help establish a more faithful in vitro model of the BBB, we have designed and fabricated a microfluidic device that is comprised of both a vascular chamber and a brain chamber separated by a porous membrane. This design allows for cell-to-cell communication between endothelial cells, astrocytes, and pericytes and independent perfusion of both compartments separated by the membrane. This NeuroVascular Unit (NVU) represents approximately one-millionth of the human brain, and hence, has sufficient cell mass to support a breadth of analytical measurements. The NVU has been validated with both fluorescein isothiocyanate (FITC)-dextran diffusion and transendothelial electrical resistance. The NVU has enabled in vitro modeling of the BBB using all human cell types and sampling effluent from both sides of the barrier.
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Affiliation(s)
| | - Virginia Pensabene
- Department of Biomedical Engineering, Vanderbilt University , Nashville, Tennessee 37235, USA
| | | | - Vanessa Allwardt
- Department of Physics and Astronomy, Vanderbilt University , Nashville, Tennessee 37235, USA
| | - M Diana Neely
- Department of Neurology, Vanderbilt Kennedy Center, Vanderbilt Brain Institute, Vanderbilt Center in Molecular Toxicology, Vanderbilt University , Nashville, Tennessee 37232, USA
| | - Mingjian Shi
- Department of Biological Sciences, Vanderbilt University , Nashville, Tennessee 37235, USA
| | - Clayton M Britt
- Department of Physics and Astronomy, Vanderbilt University , Nashville, Tennessee 37235, USA
| | - Orlando S Hoilett
- Department of Physics and Astronomy, Vanderbilt University , Nashville, Tennessee 37235, USA
| | - Qing Yang
- Department of Physics and Astronomy, Vanderbilt University , Nashville, Tennessee 37235, USA
| | - Bryson M Brewer
- Department of Mechanical Engineering, Vanderbilt University , Nashville, Tennessee 37235, USA
| | | | | | - James M May
- Department of Molecular Physiology and Biophysics, Vanderbilt University , Nashville, Tennessee 37235, USA
| | - Donna J Webb
- Department of Biological Sciences, Vanderbilt University , Nashville, Tennessee 37235, USA
| | - Deyu Li
- Department of Mechanical Engineering, Vanderbilt University , Nashville, Tennessee 37235, USA
| | - Aaron B Bowman
- Department of Neurology, Vanderbilt Kennedy Center, Vanderbilt Brain Institute, Vanderbilt Center in Molecular Toxicology, Vanderbilt University , Nashville, Tennessee 37232, USA
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23
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Ivanovic M, Petrovic J, Miletic M, Danicic A, Bojovic B, Vukcevic M, Lazovic B, Gluvic Z, Hadzievski L, Allsop T, Webb DJ. Rib-cage-movement measurements as a potential new trigger signal in non-invasive mechanical ventilation. Annu Int Conf IEEE Eng Med Biol Soc 2015; 2015:4511-4514. [PMID: 26737297 DOI: 10.1109/embc.2015.7319397] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
Non-invasive ventilation performed through an oronasal mask is a standard in clinical and homecare mechanical ventilation. Besides all its advantages, inevitable leaks through the mask cause errors in the feedback information provided by the airflow sensor and, hence, patient-ventilator asynchrony with multiple negative consequences. Here we investigate a new way to provide a trigger to the ventilator. The method is based on the measurement of rib cage movement at the onset of inspiration and during breathing by fibre-optic sensors. In a series of simultaneous measurements by a long-period fibre grating sensor and pneumotachograph we provide the statistical evidence of the 200 ms lag of the pneumo with respect the fibre-optic signal. The lag is registered consistently across three independent delay metrics. Further, we discuss exceptions from this trend and identify the needed improvements to the proposed fibre-sensing scheme.
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24
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Turtle EJ, Sule AA, Webb DJ, Bath LE. Aortic dissection in children and adolescents with Turner syndrome: risk factors and management recommendations. Arch Dis Child 2015; 100:662-6. [PMID: 25573747 DOI: 10.1136/archdischild-2014-307080] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/02/2014] [Accepted: 12/10/2014] [Indexed: 01/15/2023]
Abstract
There is a general lack of awareness of the risk of aortic dissection in Turner syndrome (TS) from both patients with TS and their physicians. Patients often ignore symptoms for up to 24 h before seeking medical advice, significantly increasing their risk of death. A clinical profile of those at risk of dissection is emerging and includes the presence of congenital heart defects, aortic dilatation and hypertension. MRI has revolutionised the visualisation of cardiovascular anatomy in TS but remains underutilised, especially in children and adolescents, and there is currently little guidance on blood pressure (BP) assessment or hypertension management. Children and adolescents with TS at risk of dissection could be easily identified by timely imaging and BP assessment. This would allow medical management or surgical intervention to be put in place to reduce the risk of this major, and often fatal, complication. Since guidance is lacking, we have reviewed the literature on the risk factors for dissection in TS during childhood and adolescence, and make recommendations on the assessment and management of these patients.
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Affiliation(s)
- E J Turtle
- Edinburgh Centre for Endocrinology, Western General Hospital, Edinburgh, UK
| | - A A Sule
- Tan Tock Seng Hospital, Singapore, Singapore
| | - D J Webb
- Queen's Medical Research Institute, University of Edinburgh/BHF Centre for Cardiovascular Science, Edinburgh, UK
| | - L E Bath
- Edinburgh Centre for Endocrinology, Royal Hospital for Sick Children, Edinburgh, UK
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25
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Marin A, Weir-McCall JR, Webb DJ, van Beek EJR, Mirsadraee S. Imaging of cardiovascular risk in patients with Turner's syndrome. Clin Radiol 2015; 70:803-14. [PMID: 25917542 PMCID: PMC4509713 DOI: 10.1016/j.crad.2015.03.009] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [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: 12/17/2014] [Revised: 02/17/2015] [Accepted: 03/19/2015] [Indexed: 01/14/2023]
Abstract
Turner's syndrome is a disorder defined by an absent or structurally abnormal second X chromosome and affects around 1 in 2000 newborn females. The standardised mortality ratio in Turner's syndrome is around three-times higher than in the general female population, mainly as a result of cardiovascular disorders. Most striking is the early age at which Turner's syndrome patients develop the life-threatening complications of cardiovascular disorders compared to the general population. The cardiovascular risk stratification in Turner's syndrome is challenging and imaging is not systematically used. The aim of this article is to review cardiovascular risks in this group of patients and discuss a systematic imaging approach for early identification of cardiovascular disorders in these patients.
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Affiliation(s)
- A Marin
- Clinical Research Imaging Centre, Queen's Medical Research Institute, University of Edinburgh, Edinburgh EH16 4TJ, UK
| | - J R Weir-McCall
- Division of Cardiovascular and Diabetes Medicine, Ninewells Hospital & Medical School, Dundee DD1 9SY, UK
| | - D J Webb
- Queen's Medical Research Institute, University of Edinburgh/BHF Centre for Cardiovascular Science, Edinburgh EH16 4TJ, UK
| | - E J R van Beek
- Clinical Research Imaging Centre, Queen's Medical Research Institute, University of Edinburgh, Edinburgh EH16 4TJ, UK
| | - S Mirsadraee
- Clinical Research Imaging Centre, Queen's Medical Research Institute, University of Edinburgh, Edinburgh EH16 4TJ, UK.
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26
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Webb DJ, Masumori S. Role of endothelin in the regulation of vascular tone and blood pressure. Contrib Nephrol 2015; 119:1-7. [PMID: 8783583 DOI: 10.1159/000425440] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Affiliation(s)
- D J Webb
- Clinical Pharmacology Unit and Research Centre, University Department of Medicine, Western General Hospital, Edinburgh, UK
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27
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Sáez-Rodríguez D, Nielsen K, Bang O, Webb DJ. Time-dependent variation of fiber Bragg grating reflectivity in PMMA-based polymer optical fibers. Opt Lett 2015; 40:1476-1479. [PMID: 25831363 DOI: 10.1364/ol.40.001476] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
In this Letter, we investigate the effects of viscoelasticity on both the strength and resonance wavelength of two fiber Bragg gratings (FBGs) inscribed in microstructured polymer optical fiber (mPOF) made of undoped PMMA. Both FBGs were inscribed under a strain of 1% in order to increase the material photosensitivity. After the inscription, the strain was released, and the FBGs spectra were monitored. We initially observed a decrease of the reflection down to zero after which it began to increase. After that, strain tests were carried out to confirm the results, and finally the gratings were monitored for a further 120 days, with a stable reflection response being observed beyond 50 days.
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28
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Evans JC, Robinson CM, Shi M, Webb DJ. The guanine nucleotide exchange factor (GEF) Asef2 promotes dendritic spine formation via Rac activation and spinophilin-dependent targeting. J Biol Chem 2015; 290:10295-308. [PMID: 25750125 DOI: 10.1074/jbc.m114.605543] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [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: 08/17/2014] [Indexed: 11/06/2022] Open
Abstract
Dendritic spines are actin-rich protrusions that establish excitatory synaptic contacts with surrounding neurons. Reorganization of the actin cytoskeleton is critical for the development and plasticity of dendritic spines, which is the basis for learning and memory. Rho family GTPases are emerging as important modulators of spines and synapses, predominantly through their ability to regulate actin dynamics. Much less is known, however, about the function of guanine nucleotide exchange factors (GEFs), which activate these GTPases, in spine and synapse development. In this study we show that the Rho family GEF Asef2 is found at synaptic sites, where it promotes dendritic spine and synapse formation. Knockdown of endogenous Asef2 with shRNAs impairs spine and synapse formation, whereas exogenous expression of Asef2 causes an increase in spine and synapse density. This effect of Asef2 on spines and synapses is abrogated by expression of GEF activity-deficient Asef2 mutants or by knockdown of Rac, suggesting that Asef2-Rac signaling mediates spine development. Because Asef2 interacts with the F-actin-binding protein spinophilin, which localizes to spines, we investigated the role of spinophilin in Asef2-promoted spine formation. Spinophilin recruits Asef2 to spines, and knockdown of spinophilin hinders spine and synapse formation in Asef2-expressing neurons. Furthermore, inhibition of N-methyl-d-aspartate receptor (NMDA) activity blocks spinophilin-mediated localization of Asef2 to spines. These results collectively point to spinophilin-Asef2-Rac signaling as a novel mechanism for the development of dendritic spines and synapses.
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Affiliation(s)
- J Corey Evans
- From the Department of Biological Sciences and the Kennedy Center for Research on Human Development and
| | - Cristina M Robinson
- From the Department of Biological Sciences and the Kennedy Center for Research on Human Development and
| | - Mingjian Shi
- From the Department of Biological Sciences and the Kennedy Center for Research on Human Development and
| | - Donna J Webb
- From the Department of Biological Sciences and the Kennedy Center for Research on Human Development and the Department of Cancer Biology, Vanderbilt University, Nashville, Tennessee 37235
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29
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Ao M, Brewer BM, Yang L, Franco Coronel OE, Hayward SW, Webb DJ, Li D. Stretching fibroblasts remodels fibronectin and alters cancer cell migration. Sci Rep 2015; 5:8334. [PMID: 25660754 PMCID: PMC4321168 DOI: 10.1038/srep08334] [Citation(s) in RCA: 64] [Impact Index Per Article: 7.1] [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: 09/14/2014] [Accepted: 01/13/2015] [Indexed: 01/07/2023] Open
Abstract
Most investigations of cancer-stroma interactions have focused on biochemical signaling effects, with much less attention being paid to biophysical factors. In this study, we investigated the role of mechanical stimuli on human prostatic fibroblasts using a microfluidic platform that was adapted for our experiments and further developed for both repeatable performance among multiple assays and for compatibility with high-resolution confocal microscopy. Results show that mechanical stretching of normal tissue-associated fibroblasts (NAFs) alters the structure of secreted fibronectin. Specifically, unstretched NAFs deposit and assemble fibronectin in a random, mesh-like arrangement, while stretched NAFs produce matrix with a more organized, linearly aligned structure. Moreover, the stretched NAFs exhibited an enhanced capability for directing co-cultured cancer cell migration in a persistent manner. Furthermore, we show that stretching NAFs triggers complex biochemical signaling events through the observation of increased expression of platelet derived growth factor receptor α (PDGFRα). A comparison of these behaviors with those of cancer-associated fibroblasts (CAFs) indicates that the observed phenotypes of stretched NAFs are similar to those associated with CAFs, suggesting that mechanical stress is a critical factor in NAF activation and CAF genesis.
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Affiliation(s)
- Mingfang Ao
- Department of Biological Sciences, Vanderbilt University, Nashville, TN
| | - Bryson M Brewer
- Department of Mechanical Engineering, Vanderbilt University, Nashville, TN
| | - Lijie Yang
- Department of Mechanical Engineering, Vanderbilt University, Nashville, TN
| | - Omar E Franco Coronel
- 1] Department of Cancer Biology, Vanderbilt University, Nashville, TN [2] Department of Urologic Surgery, Vanderbilt University, Nashville, TN
| | - Simon W Hayward
- 1] Department of Cancer Biology, Vanderbilt University, Nashville, TN [2] Department of Urologic Surgery, Vanderbilt University, Nashville, TN
| | - Donna J Webb
- 1] Department of Biological Sciences, Vanderbilt University, Nashville, TN [2] Department of Cancer Biology, Vanderbilt University, Nashville, TN
| | - Deyu Li
- Department of Mechanical Engineering, Vanderbilt University, Nashville, TN
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Broussard JA, Diggins NL, Hummel S, Georgescu W, Quaranta V, Webb DJ. Automated analysis of cell-matrix adhesions in 2D and 3D environments. Sci Rep 2015; 5:8124. [PMID: 25630460 PMCID: PMC4309964 DOI: 10.1038/srep08124] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [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: 09/08/2014] [Accepted: 01/06/2015] [Indexed: 01/01/2023] Open
Abstract
Cell-matrix adhesions are of great interest because of their contribution to numerous biological processes, including cell migration, differentiation, proliferation, survival, tissue morphogenesis, wound healing, and tumorigenesis. Adhesions are dynamic structures that are classically defined on two-dimensional (2D) substrates, though the need to analyze adhesions in more physiologic three-dimensional (3D) environments is being increasingly recognized. However, progress has been greatly hampered by the lack of available tools to analyze adhesions in 3D environments. To address this need, we have developed a platform for the automated analysis, segmentation, and tracking of adhesions (PAASTA) based on an open source MATLAB framework, CellAnimation. PAASTA enables the rapid analysis of adhesion dynamics and many other adhesion characteristics, such as lifetime, size, and location, in 3D environments and on traditional 2D substrates. We manually validate PAASTA and utilize it to quantify rate constants for adhesion assembly and disassembly as well as adhesion lifetime and size in 3D matrices. PAASTA will be a valuable tool for characterizing adhesions and for deciphering the molecular mechanisms that regulate adhesion dynamics in 3D environments.
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Affiliation(s)
- Joshua A Broussard
- Department of Biological Sciences and Vanderbilt Kennedy Center for Research on Human Development, Vanderbilt University, Nashville, Tennessee 37235
| | - Nicole L Diggins
- Department of Biological Sciences and Vanderbilt Kennedy Center for Research on Human Development, Vanderbilt University, Nashville, Tennessee 37235
| | - Stephen Hummel
- Center for Cancer Systems Biology at Vanderbilt, Vanderbilt University, Nashville, Tennessee 37235
| | - Walter Georgescu
- 1] Center for Cancer Systems Biology at Vanderbilt, Vanderbilt University, Nashville, Tennessee 37235 [2] Vanderbilt Institute for Integrative Biosystems Research and Education (VIBRE), Vanderbilt University, Nashville, Tennessee 37235 [3] Department of Biomedical Engineering, Vanderbilt University, Nashville, Tennessee 37235
| | - Vito Quaranta
- 1] Center for Cancer Systems Biology at Vanderbilt, Vanderbilt University, Nashville, Tennessee 37235 [2] Vanderbilt Institute for Integrative Biosystems Research and Education (VIBRE), Vanderbilt University, Nashville, Tennessee 37235 [3] Department of Cancer Biology, Vanderbilt University, Nashville, Tennessee 37235
| | - Donna J Webb
- 1] Department of Biological Sciences and Vanderbilt Kennedy Center for Research on Human Development, Vanderbilt University, Nashville, Tennessee 37235 [2] Vanderbilt Institute for Integrative Biosystems Research and Education (VIBRE), Vanderbilt University, Nashville, Tennessee 37235 [3] Department of Cancer Biology, Vanderbilt University, Nashville, Tennessee 37235
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Abstract
A microfluidic cell co-culture platform that uses a liquid fluorocarbon oil barrier to separate cells into different culture chambers has been developed. Characterization indicates that the oil barrier could be effective for multiple days, and a maximum pressure difference between the oil barrier and aqueous media in the cell culture chamber could be as large as ~3.43 kPa before the oil barrier fails. Biological applications have been demonstrated with the separate transfection of two groups of primary hippocampal neurons with two different fluorescent proteins and subsequent observation of synaptic contacts between the neurons. In addition, the quality of the fluidic seal provided by the oil barrier is shown to be greater than that of an alternative solid-PDMS valve barrier design by testing the ability of each device to block low molecular weight CellTracker dyes used to stain cells in the culture chambers.
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Affiliation(s)
- Bryson M Brewer
- Department of Mechanical Engineering, Vanderbilt University, Nashville, TN, 37235-1592, USA
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32
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Sáez-Rodríguez D, Nielsen K, Bang O, Webb DJ. Photosensitivity mechanism of undoped poly(methyl methacrylate) under UV radiation at 325 nm and its spatial resolution limit. Opt Lett 2014; 39:3421-3424. [PMID: 24978501 DOI: 10.1364/ol.39.003421] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
In this Letter, we provide evidence suggesting that the main photosensitive mechanism of an undoped poly(methyl methacrylate)-based microstructured optical fiber under UV radiation at 325 nm is a competitive process of both photodegradation and polymerization. We found experimentally that increasing strain during photo-inscription leads to an increased photosensitivity, which is evidence of photodegradation. Likewise, refractive index change in the fiber was measured to be positive, which provides evidence for further polymerization of the material. Finally, we relate the data obtained to the spatial recording resolution of the samples.
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Evans JC, Hines KM, Forsythe JG, Erdogan B, Shi M, Hill S, Rose KL, McLean JA, Webb DJ. Phosphorylation of serine 106 in Asef2 regulates cell migration and adhesion turnover. J Proteome Res 2014; 13:3303-13. [PMID: 24874604 PMCID: PMC4084842 DOI: 10.1021/pr5001384] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [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] [Indexed: 11/30/2022]
Abstract
![]()
Asef2, a 652-amino acid protein,
is a guanine nucleotide exchange
factor (GEF) that regulates cell migration and other processes via
activation of Rho family GTPases, including Rac. Binding of the tumor
suppressor adenomatous polyposis coli (APC) to Asef2 is known to induce
its GEF activity; however, little is currently known about other modes
of Asef2 regulation. Here, we investigated the role of phosphorylation
in regulating Asef2 activity and function. Using high-resolution mass
spectrometry (MS) and tandem mass spectrometry (MS/MS), we obtained
complete coverage of all phosphorylatable residues and identified
six phosphorylation sites. One of these, serine 106 (S106), was particularly
intriguing as a potential regulator of Asef2 activity because of its
location within the APC-binding domain. Interestingly, mutation of
this serine to alanine (S106A), a non-phosphorylatable analogue, greatly
diminished the ability of Asef2 to activate Rac, while a phosphomimetic
mutation (serine to aspartic acid, S106D) enhanced Rac activation.
Furthermore, expression of these mutants in HT1080 cells demonstrated
that phosphorylation of S106 is critical for Asef2-promoted migration
and for cell-matrix adhesion assembly and disassembly (adhesion turnover),
which is a process that facilitates efficient migration. Collectively,
our results show that phosphorylation of S106 modulates Asef2 GEF
activity and Asef2-mediated cell migration and adhesion turnover.
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Affiliation(s)
- J Corey Evans
- Department of Biological Sciences and Vanderbilt Kennedy Center for Research on Human Development, ‡Department of Chemistry, §Vanderbilt Institute for Chemical Biology (VICB), ∥Vanderbilt Institute for Integrative Biosystems Research and Education (VIIBRE), ⊥Mass Spectrometry Research Center, #Department of Biochemistry, and ●Department of Cancer Biology, Vanderbilt University , Nashville, Tennessee 37235, United States
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34
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Alcendor DJ, Block FE, Cliffel DE, Daniels JS, Ellacott KLJ, Goodwin CR, Hofmeister LH, Li D, Markov DA, May JC, McCawley LJ, McLaughlin B, McLean JA, Niswender KD, Pensabene V, Seale KT, Sherrod SD, Sung HJ, Tabb DL, Webb DJ, Wikswo JP. Neurovascular unit on a chip: implications for translational applications. Stem Cell Res Ther 2013; 4 Suppl 1:S18. [PMID: 24564885 PMCID: PMC4029462 DOI: 10.1186/scrt379] [Citation(s) in RCA: 49] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
The blood-brain barrier (BBB) dynamically controls exchange between the brain and the body, but this interaction cannot be studied directly in the intact human brain or sufficiently represented by animal models. Most existing in vitro BBB models do not include neurons and glia with other BBB elements and do not adequately predict drug efficacy and toxicity. Under the National Institutes of Health Microtissue Initiative, we are developing a three-dimensional, multicompartment, organotypic microphysiological system representative of a neurovascular unit of the brain. The neurovascular unit system will serve as a model to study interactions between the central nervous system neurons and the cerebral spinal fluid (CSF) compartment, all coupled to a realistic blood-surrogate supply and venous return system that also incorporates circulating immune cells and the choroid plexus. Hence all three critical brain barriers will be recapitulated: blood-brain, brain-CSF, and blood-CSF. Primary and stem cell-derived human cells will interact with a variety of agents to produce critical chemical communications across the BBB and between brain regions. Cytomegalovirus, a common herpesvirus, will be used as an initial model of infections regulated by the BBB. This novel technological platform, which combines innovative microfluidics, cell culture, analytical instruments, bioinformatics, control theory, neuroscience, and drug discovery, will replicate chemical communication, molecular trafficking, and inflammation in the brain. The platform will enable targeted and clinically relevant nutritional and pharmacologic interventions for or prevention of such chronic diseases as obesity and acute injury such as stroke, and will uncover potential adverse effects of drugs. If successful, this project will produce clinically useful technologies and reveal new insights into how the brain receives, modifies, and is affected by drugs, other neurotropic agents, and diseases.
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Lin WH, Hurley JT, Raines AN, Cheney RE, Webb DJ. Myosin X and its motorless isoform differentially modulate dendritic spine development by regulating trafficking and retention of vasodilator-stimulated phosphoprotein. Development 2013. [DOI: 10.1242/dev.105171] [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: 11/20/2022]
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36
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Jean L, Majumdar D, Shi M, Hinkle LE, Diggins NL, Ao M, Broussard JA, Evans JC, Choma DP, Webb DJ. Activation of Rac by Asef2 promotes myosin II-dependent contractility to inhibit cell migration on type I collagen. J Cell Sci 2013; 126:5585-97. [PMID: 24144700 DOI: 10.1242/jcs.131060] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
Non-muscle myosin II (MyoII) contractility is central to the regulation of numerous cellular processes, including migration. Rho is a well-characterized modulator of actomyosin contractility, but the function of other GTPases, such as Rac, in regulating contractility is currently not well understood. Here, we show that activation of Rac by the guanine nucleotide exchange factor Asef2 (also known as SPATA13) impairs migration on type I collagen through a MyoII-dependent mechanism that enhances contractility. Knockdown of endogenous Rac or treatment of cells with a Rac-specific inhibitor decreases the amount of active MyoII, as determined by serine 19 (S19) phosphorylation, and negates the Asef2-promoted increase in contractility. Moreover, treatment of cells with blebbistatin, which inhibits MyoII activity, abolishes the Asef2-mediated effect on migration. In addition, Asef2 slows the turnover of adhesions in protrusive regions of cells by promoting large mature adhesions, which has been linked to actomyosin contractility, with increased amounts of active β1 integrin. Hence, our data reveal a new role for Rac activation, promoted by Asef2, in modulating actomyosin contractility, which is important for regulating cell migration and adhesion dynamics.
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Affiliation(s)
- Léolène Jean
- Department of Biological Sciences and Vanderbilt Kennedy Center for Research on Human Development, Nashville, TN 37203, USA
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37
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Sáez-Rodríguez D, Nielsen K, Rasmussen HK, Bang O, Webb DJ. Highly photosensitive polymethyl methacrylate microstructured polymer optical fiber with doped core. Opt Lett 2013; 38:3769-3772. [PMID: 24081048 DOI: 10.1364/ol.38.003769] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
In this Letter, we report the fabrication of a highly photosensitive, microstructured polymer optical fiber using benzyl dimethyl ketal as a dopant, as well as the inscription of a fiber Bragg grating in the fiber. A refractive index change in the core of at least 3.2×10(-4) has been achieved, providing a grating with a strong transmission rejection of -23 dB with an inscription time of only 13 min. The fabrication method has a big advantage compared to doping step index fiber since it enables doping of the fiber without using extra dopants to compensate for the index reduction in the core introduced by the photosensitive agent.
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Abstract
A 57-year-old man presented with symptoms of intermittent claudication and was diagnosed with peripheral arterial disease. He was advised to stop smoking and start a walking programme. He had a background history of hypercholesterolaemia and erectile dysfunction, for which he was taking simvastatin and phosphodiesterase type-5 inhibitor sildenafil, respectively. After starting his exercise programme, he noted that his walking distance was more than doubled on the mornings after taking sildenafil, and he has been using sildenafil primarily for shopping trips since that time. Although this single-patient self-experiment has the potential for placebo confounding, the patient was not led to expect this benefit, and there is evidence that reduced nitric oxide bioactivity plays an important role in the pathophysiology of peripheral arterial disease. Given the biological plausibility of this effect, we feel that a randomised, blinded and placebo-controlled clinical study is warranted to confirm the benefit of phosphodiesterase type-5 inhibitors in peripheral arterial disease.
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Affiliation(s)
- EJ Turtle
- Research Fellow, Pharmacology, Toxicology and Therapeutics, Queen's Medical Research Institute, University of Edinburgh, UK
| | - ID Drummond
- Research Fellow, Pharmacology, Toxicology and Therapeutics, Queen's Medical Research Institute, University of Edinburgh, UK
| | - DJ Webb
- Christison Professor of Therapeutics and Clinical Pharmacology, Queen’s Medical Research Institute, University of Edinburgh, UK
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39
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Lin WH, Hurley JT, Raines AN, Cheney RE, Webb DJ. Myosin X and its motorless isoform differentially modulate dendritic spine development by regulating trafficking and retention of vasodilator-stimulated phosphoprotein. J Cell Sci 2013; 126:4756-68. [PMID: 23943878 DOI: 10.1242/jcs.132969] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
Myosin X (Myo10) is an unconventional myosin with two known isoforms: full-length (FL)-Myo10 that has motor activity, and a recently identified brain-expressed isoform, headless (Hdl)-Myo10, which lacks most of the motor domain. FL-Myo10 is involved in the regulation of filopodia formation in non-neuronal cells; however, the biological function of Hdl-Myo10 remains largely unknown. Here, we show that FL- and Hdl-Myo10 have important, but distinct, roles in the development of dendritic spines and synapses in hippocampal neurons. FL-Myo10 induces formation of dendritic filopodia and modulates filopodia dynamics by trafficking the actin-binding protein vasodilator-stimulated phosphoprotein (VASP) to the tips of filopodia. By contrast, Hdl-Myo10 acts on dendritic spines to enhance spine and synaptic density as well as spine head expansion by increasing the retention of VASP in spines. Thus, this study demonstrates a novel biological function for Hdl-Myo10 and an important new role for both Myo10 isoforms in the development of dendritic spines and synapses.
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Affiliation(s)
- Wan-Hsin Lin
- Department of Biological Sciences and Vanderbilt Kennedy Center for Research on Human Development, Vanderbilt University, Nashville, Tennessee 37235, USA
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40
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Allsop T, Neal R, Dvorak M, Kalli K, Rozhin A, Webb DJ. Physical characteristics of localized surface plasmons resulting from nano-scale structured multi-layer thin films deposited on D-shaped optical fiber. Opt Express 2013; 21:18765-18776. [PMID: 23938792 DOI: 10.1364/oe.21.018765] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
Novel surface plasmonic optical fiber sensors have been fabricated using multiple coatings deposited on a lapped section of a single mode fiber. UV laser irradiation processing with a phase mask produces a nano-scaled surface relief grating structure resembling nano-wires. The resulting individual corrugations produced by material compaction are approximately 20 μm long with an average width at half maximum of 100 nm and generate localized surface plasmons. Experimental data are presented that show changes in the spectral characteristics after UV processing, coupled with an overall increase in the sensitivity of the devices to surrounding refractive index. Evidence is presented that there is an optimum UV dosage (48 joules) over which no significant additional optical change is observed. The devices are characterized with regards to change in refractive index, where significantly high spectral sensitivities in the aqueous index regime are found, ranging up to 4000 nm/RIU for wavelength and 800 dB/RIU for intensity.
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Affiliation(s)
- T Allsop
- Aston Institute of Photonic Technologies, Aston University, Aston Triangle, Birmingham, B47ET, UK.
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41
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Shi M, Majumdar D, Gao Y, Brewer B, Goodwin CR, McLean JA, Li D, Webb DJ. Glia co-culture with neurons in microfluidic platforms promotes the formation and stabilization of synaptic contacts. Lab Chip 2013; 13:3008-21. [PMID: 23736663 PMCID: PMC3712871 DOI: 10.1039/c3lc50249j] [Citation(s) in RCA: 81] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/03/2023]
Abstract
Two novel microfluidic cell culture schemes, a vertically-layered set-up and a four chamber set-up, were developed for co-culturing central nervous system (CNS) neurons and glia. The cell chambers in these devices were separated by pressure-enabled valve barriers, which permitted us to control communication between the two cell types. The unique design of these devices facilitated the co-culture of glia with neurons in close proximity (∼50-100 μm), differential transfection of neuronal populations, and dynamic visualization of neuronal interactions, such as the development of synapses. With these co-culture devices, initial synaptic contact between neurons transfected with different fluorescent markers, such as green fluorescent protein (GFP) and mCherry-synaptophysin, was imaged using high-resolution fluorescence microscopy. The presence of glial cells had a profound influence on synapses by increasing the number and stability of synaptic contacts. Interestingly, as determined by liquid chromatography-ion mobility-mass spectrometry, neuron-glia co-cultures produced elevated levels of soluble factors compared to that secreted by individual neuron or glia cultures, suggesting a potential mechanism by which neuron-glia interactions could modulate synaptic function. Collectively, these results show that communication between neurons and glia is critical for the formation and stability of synapses and point to the importance of developing neuron-glia co-culture systems such as the microfluidic platforms described in this study.
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Affiliation(s)
- Mingjian Shi
- Department of Biological Sciences and Vanderbilt Kennedy Center for Research on Human Development, Vanderbilt University, Nashville TN 37235
| | - Devi Majumdar
- Department of Biological Sciences and Vanderbilt Kennedy Center for Research on Human Development, Vanderbilt University, Nashville TN 37235
| | - Yandong Gao
- Department of Mechanical Engineering, Vanderbilt University, Nashville TN 37235
| | - Bryson Brewer
- Department of Mechanical Engineering, Vanderbilt University, Nashville TN 37235
| | - Cody R. Goodwin
- Department of Chemistry, Vanderbilt University, Nashville TN 37235
| | - John A. McLean
- Department of Chemistry, Vanderbilt University, Nashville TN 37235
| | - Deyu Li
- Department of Mechanical Engineering, Vanderbilt University, Nashville TN 37235
| | - Donna J. Webb
- Department of Biological Sciences and Vanderbilt Kennedy Center for Research on Human Development, Vanderbilt University, Nashville TN 37235
- Department of Cancer Biology, Vanderbilt University, Nashville TN 37235
- Correspondence to: Donna J. Webb: ; mailing address: VU station B, Box 35-1634, Nashville, TN 37235; phone: 615-936-8274; fax: 615-343-6707
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42
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Affiliation(s)
- E J Turtle
- Queen's Medical Research Institute, University of Edinburgh/BHF Centre for Cardiovascular Science, Room E3.22, 47 Little France Crescent, Edinburgh EH16 4TJ, UK
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Broussard JA, Rappaz B, Webb DJ, Brown CM. Fluorescence resonance energy transfer microscopy as demonstrated by measuring the activation of the serine/threonine kinase Akt. Nat Protoc 2013; 8:265-81. [PMID: 23306460 DOI: 10.1038/nprot.2012.147] [Citation(s) in RCA: 104] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
This protocol describes procedures for performing fluorescence resonance energy transfer (FRET) microscopy analysis by three different methods: acceptor photobleaching, sensitized emission and spectral imaging. We also discuss anisotropy and fluorescence lifetime imaging microscopy-based FRET techniques. By using the specific example of the FRET probe Akind (Akt indicator), which is a version of Akt modified such that FRET occurs when the probe is activated by phosphorylation, indicating Akt activation. The protocol provides a detailed step-by-step description of sample preparation, image acquisition and analysis, including control samples, image corrections and the generation of quantitative FRET/CFP ratio images for both sensitized emission and spectral imaging. The sample preparation takes 2 d, equipment setup takes 2-3 h and image acquisition and analysis take 6-8 h.
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Affiliation(s)
- Joshua A Broussard
- Department of Biological Sciences and Vanderbilt Kennedy Center for Research on Human Development, Vanderbilt University, Nashville, Tennessee, USA
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Abstract
Epi-fluorescence microscopy is available in most life sciences research laboratories, and when optimized can be a central laboratory tool. In this chapter, the epi-fluorescence light path is introduced and the various components are discussed in detail. Recommendations are made for incident lamp light sources, excitation and emission filters, dichroic mirrors, objective lenses, and charge-coupled device (CCD) cameras in order to obtain the most sensitive epi-fluorescence microscope. The even illumination of metal-halide lamps combined with new "hard" coated filters and mirrors, a high resolution monochrome CCD camera, and a high NA objective lens are all recommended for high resolution and high sensitivity fluorescence imaging. Recommendations are also made for multicolor imaging with the use of monochrome cameras, motorized filter turrets, individual filter cubes, and corresponding dyes being the best choice for sensitive, high resolution multicolor imaging. Images should be collected using Nyquist sampling and images should be corrected for background intensity contributions and nonuniform illumination across the field of view. Photostable fluorescent probes and proteins that absorb a lot of light (i.e., high extinction co-efficients) and generate a lot of fluorescence signal (i.e., high quantum yields) are optimal. A neuronal immune-fluorescence labeling protocol is also presented. Finally, in order to maximize the utility of sensitive wide-field microscopes and generate the highest resolution images with high signal-to-noise, advice for combining wide-field epi-fluorescence imaging with restorative image deconvolution is presented.
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Affiliation(s)
- Donna J Webb
- Department of Biological Sciences, Vanderbilt University, Nashville, TN, USA
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Forsythe JG, Broussard JA, Lawrie JL, Kliman M, Jiao Y, Weiss SM, Webb DJ, McLean JA. Semitransparent nanostructured films for imaging mass spectrometry and optical microscopy. Anal Chem 2012; 84:10665-70. [PMID: 23146026 DOI: 10.1021/ac3022967] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
Semitransparent porous silicon substrates have been developed for pairing nanostructure-initiator mass spectrometry (NIMS) imaging with traditional optical-based microscopy techniques. Substrates were optimized to generate the largest NIMS signal while maintaining sufficient transparency to allow visible light to pass through for optical microscopy. Using these substrates, both phase-contrast and NIMS images of phospholipids from a scratch-wounded cell monolayer were obtained. NIMS images were generated using a spatial resolution of 14 μm. Coupled with further improvements in spatial resolution, this approach may allow for the localization of intact biological molecules within cells without the need for labeling.
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Affiliation(s)
- Jay G Forsythe
- Department of Chemistry, Vanderbilt University, Nashville, Tennessee 37235, USA
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Morrison EE, Turtle EJ, Webb DJ. Observing the NICEties of hypertension management. J R Coll Physicians Edinb 2012; 42:251-7. [PMID: 22953322 DOI: 10.4997/jrcpe.2012.314] [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] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
National Institute for Health and Clinical Excellence guidance for the clinical management of hypertension, published last year, proposes a step change in UK clinical practice.1 Although broadly helpful, there are some concerns about its implementation. Ambulatory blood pressure monitoring for diagnosis of hypertension, though logical, will place an additional financial burden on primary care at a time of austerity. Home blood pressure measurement may be a more practical option. Previous guidance recommended the used of thiazide diuretics as a first-line treatment option.2 Five years later, the new guidelines propose a major change, with an initial emphasis on the use of calcium channel blockers and angiotensin converting enzyme inhibitors/angiotensin receptor blockers, moving the use of thiazide-like diuretics to a third-line option. In addition, bendroflumethiazide, the mainstay of treatment in the UK over many years, has been replaced with chlortalidone, the starting doses of which are not readily available in this country. Cost-effectiveness analysis and a presumed risk of metabolic disorders has guided the rationale for these changes to the therapeutic algorithm, however this may not be robust. Importantly, unless there are special circumstances, reducing the blood pressure in hypertensive patients is more important than the means used to lower it. In future, it will be important to 'personalise' treatment more effectively and base management on lifetime risk.
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Affiliation(s)
- E E Morrison
- Clinical Pharmacology and Therapeutics ST3, Royal Infirmary of Edinburgh, UK
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Bhamber RS, Allsop T, Lloyd G, Webb DJ, Ania-Castanon JD. Arbitrary real-time three-dimensional corporal object sensing and reconstruction scheme. Opt Lett 2012; 37:3549-3551. [PMID: 22940945 DOI: 10.1364/ol.37.003549] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
A real-time three-dimensional (3D) object sensing and reconstruction scheme is presented that can be applied on any arbitrary corporeal shape. Operation is demonstrated on several calibrated objects. The system uses curvature sensors based upon in-line fiber Bragg gratings encapsulated in a low-temperature curing synthetic silicone. New methods to quantitatively evaluate the performance of a 3D object-sensing scheme are developed and appraised. It is shown that the sensing scheme yields a volumetric error of 1% to 9%, depending on the object.
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Affiliation(s)
- R S Bhamber
- Instituto de Óptica Daza de Valdés, (CSIC), Madrid, Spain
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Phillips LA, MacIntyre IM, Webb DJ. Development of an in vivo protocol for investigating natriuretic mechanisms in response to acute sodium loading in humans. BMC Proc 2012. [PMCID: PMC3426093 DOI: 10.1186/1753-6561-6-s4-o45] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/02/2022] Open
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Broussard JA, Lin WH, Majumdar D, Anderson B, Eason B, Brown CM, Webb DJ. The endosomal adaptor protein APPL1 impairs the turnover of leading edge adhesions to regulate cell migration. Mol Biol Cell 2012; 23:1486-99. [PMID: 22379109 PMCID: PMC3327316 DOI: 10.1091/mbc.e11-02-0124] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.3] [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] [Indexed: 01/09/2023] Open
Abstract
Cell migration is a complex process that requires the integration of signaling events that occur in distinct locations within the cell. Adaptor proteins, which can localize to different subcellular compartments, where they bring together key signaling proteins, are emerging as attractive candidates for controlling spatially coordinated processes. However, their function in regulating cell migration is not well understood. In this study, we demonstrate a novel role for the adaptor protein containing a pleckstrin-homology (PH) domain, phosphotyrosine-binding (PTB) domain, and leucine zipper motif 1 (APPL1) in regulating cell migration. APPL1 impairs migration by hindering the turnover of adhesions at the leading edge of cells. The mechanism by which APPL1 regulates migration and adhesion dynamics is by inhibiting the activity of the serine/threonine kinase Akt at the cell edge and within adhesions. In addition, APPL1 significantly decreases the tyrosine phosphorylation of Akt by the nonreceptor tyrosine kinase Src, which is critical for Akt-mediated cell migration. Thus, our results demonstrate an important new function for APPL1 in regulating cell migration and adhesion turnover through a mechanism that depends on Src and Akt. Moreover, our data further underscore the importance of adaptor proteins in modulating the flow of information through signaling pathways.
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Affiliation(s)
- Joshua A Broussard
- Department of Biological Sciences and Vanderbilt Kennedy Center for Research on Human Development, Nashville, TN 37235, USA
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Kelland NF, Kuc RE, McLean DL, Azfer A, Bagnall AJ, Gray GA, Gulliver-Sloan FH, Maguire JJ, Davenport AP, Kotelevtsev YV, Webb DJ. Endothelial cell-specific ETB receptor knockout: autoradiographic and histological characterisation and crucial role in the clearance of endothelin-1. Can J Physiol Pharmacol 2011; 88:644-51. [PMID: 20628430 DOI: 10.1139/y10-041] [Citation(s) in RCA: 55] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Inactivation of endothelin B receptors (ETB), either through selective pharmacological antagonism or genetic mutation, increases the circulating concentration of endothelin-1 (ET-1), suggesting ETB plays an important role in clearance of this peptide. However, the cellular site of ETB-mediated clearance has not yet been determined. We have used a novel mouse model of endothelial cell-specific knockout (KO) of ETB (EC ETB(-/-)) to evaluate the relative contribution of EC-ETB to the clearance of ET-1. Phenotypic evidence of EC-specific ETB KO was confirmed by immunocytochemistry and autoradiography. Binding of the radiolabelled selective ETB ligand BQ3020 was significantly and selectively decreased in EC-rich tissues of EC ETB(-/-) mice, including the lung, liver, and kidney. By contrast, ETA binding was unaltered. RT-PCR confirmed equal expression of ET-1 in tissue from EC ETB(-/-) mice and controls, despite increased concentration of plasma ET-1 in EC ETB(-/-). Clearance of an intravenous bolus of [(125)I]ET-1 was impaired in EC ETB(-/-) mice. Pretreatment with the selective ETB antagonist A192621 impaired [(125)I]ET-1 clearance in control animals to a similar extent, but did not further impair clearance in EC ETB(-/-) mice. These studies suggest that EC-ETB are largely responsible for the clearance of ET-1 from the circulation.
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Affiliation(s)
- N F Kelland
- Clinical Pharmacology Unit, Centre for Cardiovascular Science, University of Edinburgh, Queen's Medical Research Institute, Edinburgh EH16 4TJ, UK
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