51
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Micali G, Endres RG. Maximal information transmission is compatible with ultrasensitive biological pathways. Sci Rep 2019; 9:16898. [PMID: 31729454 PMCID: PMC6858467 DOI: 10.1038/s41598-019-53273-4] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2018] [Accepted: 10/29/2019] [Indexed: 11/16/2022] Open
Abstract
Cells are often considered input-output devices that maximize the transmission of information by converting extracellular stimuli (input) via signaling pathways (communication channel) to cell behavior (output). However, in biological systems outputs might feed back into inputs due to cell motility, and the biological channel can change by mutations during evolution. Here, we show that the conventional channel capacity obtained by optimizing the input distribution for a fixed channel may not reflect the global optimum. In a new approach we analytically identify both input distributions and input-output curves that optimally transmit information, given constraints from noise and the dynamic range of the channel. We find a universal optimal input distribution only depending on the input noise, and we generalize our formalism to multiple outputs (or inputs). Applying our formalism to Escherichia coli chemotaxis, we find that its pathway is compatible with optimal information transmission despite the ultrasensitive rotary motors.
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Affiliation(s)
- Gabriele Micali
- Department of Life Sciences, Imperial College, London, UK.,Centre for Integrative Systems Biology and Bioinformatics, Imperial College, London, UK.,Department of Environmental Microbiology, Eawag, Dübendorf, Switzerland.,Department of Environmental Systems Science, ETH Zürich, Zürich, Switzerland
| | - Robert G Endres
- Department of Life Sciences, Imperial College, London, UK. .,Centre for Integrative Systems Biology and Bioinformatics, Imperial College, London, UK.
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52
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Hopkins A, Camley BA. Leader cells in collective chemotaxis: Optimality and trade-offs. Phys Rev E 2019; 100:032417. [PMID: 31639926 DOI: 10.1103/physreve.100.032417] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2019] [Indexed: 11/06/2022]
Abstract
Clusters of cells can work together in order to follow a signal gradient, chemotaxing even when single cells do not. Cells in different regions of collectively migrating neural crest streams show different gene expression profiles, suggesting that cells may specialize to leader and follower roles. We use a minimal mathematical model to understand when this specialization is advantageous. In our model, leader cells sense the gradient with an accuracy that depends on the kinetics of ligand-receptor binding, while follower cells follow the cluster's direction with a finite error. Intuitively, specialization into leaders and followers should be optimal when a few cells have more information than the rest of the cluster, such as in the presence of a sharp transition in chemoattractant concentration. We do find this-but also find that high levels of specialization can be optimal in the opposite limit of very shallow gradients. We also predict that the best location for leaders may not be at the front of the cluster. In following leaders, clusters may have to choose between speed and flexibility. Clusters with only a few leaders can take orders of magnitude more time to reorient than all-leader clusters.
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Affiliation(s)
- Austin Hopkins
- Department of Physics & Astronomy, Johns Hopkins University, Baltimore, Maryland 21218, USA
| | - Brian A Camley
- Department of Physics & Astronomy and Department of Biophysics, Johns Hopkins University, Baltimore, Maryland 21218, USA
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53
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Sauerwald J, Backer W, Matzat T, Schnorrer F, Luschnig S. Matrix metalloproteinase 1 modulates invasive behavior of tracheal branches during entry into Drosophila flight muscles. eLife 2019; 8:48857. [PMID: 31577228 PMCID: PMC6795481 DOI: 10.7554/elife.48857] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2019] [Accepted: 10/01/2019] [Indexed: 12/30/2022] Open
Abstract
Tubular networks like the vasculature extend branches throughout animal bodies, but how developing vessels interact with and invade tissues is not well understood. We investigated the underlying mechanisms using the developing tracheal tube network of Drosophila indirect flight muscles (IFMs) as a model. Live imaging revealed that tracheal sprouts invade IFMs directionally with growth-cone-like structures at branch tips. Ramification inside IFMs proceeds until tracheal branches fill the myotube. However, individual tracheal cells occupy largely separate territories, possibly mediated by cell-cell repulsion. Matrix metalloproteinase 1 (MMP1) is required in tracheal cells for normal invasion speed and for the dynamic organization of growth-cone-like branch tips. MMP1 remodels the CollagenIV-containing matrix around branch tips, which show differential matrix composition with low CollagenIV levels, while Laminin is present along tracheal branches. Thus, tracheal-derived MMP1 sustains branch invasion by modulating the dynamic behavior of sprouting branches as well as properties of the surrounding matrix.
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Affiliation(s)
- Julia Sauerwald
- Institute for Zoophysiology, University of Münster, Münster, Germany.,Cluster of Excellence EXC 1003, Cells in Motion (CiM), Münster, Germany
| | - Wilko Backer
- Institute for Zoophysiology, University of Münster, Münster, Germany.,Cluster of Excellence EXC 1003, Cells in Motion (CiM), Münster, Germany
| | - Till Matzat
- Institute for Zoophysiology, University of Münster, Münster, Germany.,Cluster of Excellence EXC 1003, Cells in Motion (CiM), Münster, Germany
| | | | - Stefan Luschnig
- Institute for Zoophysiology, University of Münster, Münster, Germany.,Cluster of Excellence EXC 1003, Cells in Motion (CiM), Münster, Germany
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54
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Norden C, Lecaudey V. Collective cell migration: general themes and new paradigms. Curr Opin Genet Dev 2019; 57:54-60. [PMID: 31430686 DOI: 10.1016/j.gde.2019.06.013] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2019] [Revised: 06/13/2019] [Accepted: 06/21/2019] [Indexed: 11/16/2022]
Abstract
Collective cell migration plays essential roles in embryogenesis and also contributes to disease states. Recent years have seen immense progress in understanding mechanisms and overarching concepts of collective cell migration. Self-organization of moving groups emerges as an important common feature. This includes self-generating gradients, internal chemotaxis or mechanotaxis and contact-dependent polarization within migrating cell groups. Here, we will discuss these concepts and their applications to classical models of collective cell migration. Further, we discuss new models and paradigms of collective cell migration and elaborate on open questions and future challenges. Answering these questions will help to expand our appreciation of this exciting theme in developmental cell biology and contribute to the understanding of disease states.
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Affiliation(s)
- Caren Norden
- Max Planck Institute of Molecular Cell Biology and Genetics, Pfotenhauerstraße 108, 01307 Dresden, Germany.
| | - Virginie Lecaudey
- Department of Developmental Biology of Vertebrates, Institute for Cell Biology and Neuroscience, Goethe University Frankfurt am Main, Frankfurt am Main, Germany.
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55
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Abstract
Neural crest cells are a transient embryonic cell population that migrate collectively to various locations throughout the embryo to contribute a number of cell types to several organs. After induction, the neural crest delaminates and undergoes an epithelial-to-mesenchymal transition before migrating through intricate yet characteristic paths. The neural crest exhibits a variety of migratory behaviors ranging from sheet-like mass migration in the cephalic regions to chain migration in the trunk. During their journey, neural crest cells rely on a range of signals both from their environment and within the migrating population for navigating through the embryo as a collective. Here we review these interactions and mechanisms, including chemotactic cues of neural crest cells' migration.
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Affiliation(s)
- András Szabó
- Department of Cell and Developmental Biology, University College London, London WC1E 6BT, United Kingdom;
| | - Roberto Mayor
- Department of Cell and Developmental Biology, University College London, London WC1E 6BT, United Kingdom;
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56
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Tweedy L, Witzel P, Heinrich D, Insall RH, Endres RG. Screening by changes in stereotypical behavior during cell motility. Sci Rep 2019; 9:8784. [PMID: 31217532 PMCID: PMC6584642 DOI: 10.1038/s41598-019-45305-w] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2018] [Accepted: 06/04/2019] [Indexed: 02/01/2023] Open
Abstract
Stereotyped behaviors are series of postures that show very little variability between repeats. They have been used to classify the dynamics of individuals, groups and species without reference to the lower-level mechanisms that drive them. Stereotypes are easily identified in animals due to strong constraints on the number, shape, and relative positions of anatomical features, such as limbs, that may be used as landmarks for posture identification. In contrast, the identification of stereotypes in single cells poses a significant challenge as the cell lacks these landmark features, and finding constraints on cell shape is a non-trivial task. Here, we use the maximum caliber variational method to build a minimal model of cell behavior during migration. Without reference to biochemical details, we are able to make behavioral predictions over timescales of minutes using only changes in cell shape over timescales of seconds. We use drug treatment and genetics to demonstrate that maximum caliber descriptors can discriminate between healthy and aberrant migration, thereby showing potential applications for maximum caliber methods in automated disease screening, for example in the identification of behaviors associated with cancer metastasis.
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Affiliation(s)
- Luke Tweedy
- Department of Life Sciences and Centre for Integrative Systems Biology and Bioinformatics, Imperial College, London, United Kingdom
- CRUK Beatson Institute, Glasgow, G61 1BD, Scotland, UK
| | - Patrick Witzel
- Fraunhofer Institute for Silicate Research ISC, Neunerplatz 2, 97082, Würzburg, Germany
| | - Doris Heinrich
- Fraunhofer Institute for Silicate Research ISC, Neunerplatz 2, 97082, Würzburg, Germany
- Leiden Institute of Physics, LION, Leiden University, Leiden, Netherlands
| | | | - Robert G Endres
- Department of Life Sciences and Centre for Integrative Systems Biology and Bioinformatics, Imperial College, London, United Kingdom.
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57
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Holle A, Govindan Kutty Devi N, Clar K, Fan A, Saif T, Kemkemer R, Spatz JP. Cancer Cells Invade Confined Microchannels via a Self-Directed Mesenchymal-to-Amoeboid Transition. NANO LETTERS 2019; 19:2280-2290. [PMID: 30775927 PMCID: PMC6463244 DOI: 10.1021/acs.nanolett.8b04720] [Citation(s) in RCA: 74] [Impact Index Per Article: 14.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/23/2018] [Revised: 02/11/2019] [Indexed: 05/30/2023]
Abstract
Cancer cell invasion through physical barriers in the extracellular matrix (ECM) requires a complex synergy of traction force against the ECM, mechanosensitive feedback, and subsequent cytoskeletal rearrangement. PDMS microchannels were used to investigate the transition from mesenchymal to amoeboid invasion in cancer cells. Migration was faster in narrow 3 μm-wide channels than in wider 10 μm channels, even in the absence of cell-binding ECM proteins. Cells permeating narrow channels exhibited blebbing and had smooth leading edge profiles, suggesting an ECM-induced transition from mesenchymal invasion to amoeboid invasion. Live cell labeling revealed a mechanosensing period in which the cell attempts mesenchymal-based migration, reorganizes its cytoskeleton, and proceeds using an amoeboid phenotype. Rho/ROCK (amoeboid) and Rac (mesenchymal) pathway inhibition revealed that amoeboid invasion through confined environments relies on both pathways in a time- and ECM-dependent manner. This demonstrates that cancer cells can dynamically modify their invasion programming to navigate physically confining matrix conditions.
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Affiliation(s)
- Andrew
W. Holle
- Department
of Cellular Biophysics, Max Planck Institute
for Medical Research, Heidelberg 69120, Germany
- Department
of Biophysical Chemistry, University of
Heidelberg, Heidelberg 69117, Germany
| | | | - Kim Clar
- Department
of Cellular Biophysics, Max Planck Institute
for Medical Research, Heidelberg 69120, Germany
- Department
of Applied Chemistry, Reutlingen University, Reutlingen 72762, Germany
| | - Anthony Fan
- Department
of Mechanical Science and Engineering, University
of Illinois at Urbana−Champaign, Urbana, Illinois 61801, United States
| | - Taher Saif
- Department
of Mechanical Science and Engineering, University
of Illinois at Urbana−Champaign, Urbana, Illinois 61801, United States
| | - Ralf Kemkemer
- Department
of Cellular Biophysics, Max Planck Institute
for Medical Research, Heidelberg 69120, Germany
- Department
of Applied Chemistry, Reutlingen University, Reutlingen 72762, Germany
| | - Joachim P. Spatz
- Department
of Cellular Biophysics, Max Planck Institute
for Medical Research, Heidelberg 69120, Germany
- Department
of Biophysical Chemistry, University of
Heidelberg, Heidelberg 69117, Germany
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58
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Nichols JME, Paschke P, Peak-Chew S, Williams TD, Tweedy L, Skehel M, Stephens E, Chubb JR, Kay RR. The Atypical MAP Kinase ErkB Transmits Distinct Chemotactic Signals through a Core Signaling Module. Dev Cell 2019; 48:491-505.e9. [PMID: 30612939 PMCID: PMC6397043 DOI: 10.1016/j.devcel.2018.12.001] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2017] [Revised: 10/15/2018] [Accepted: 12/03/2018] [Indexed: 12/20/2022]
Abstract
Signaling from chemoattractant receptors activates the cytoskeleton of crawling cells for chemotaxis. We show using phosphoproteomics that different chemoattractants cause phosphorylation of the same core set of around 80 proteins in Dictyostelium cells. Strikingly, the majority of these are phosphorylated at an [S/T]PR motif by the atypical MAP kinase ErkB. Unlike most chemotactic responses, ErkB phosphorylations are persistent and do not adapt to sustained stimulation with chemoattractant. ErkB integrates dynamic autophosphorylation with chemotactic signaling through G-protein-coupled receptors. Downstream, our phosphoproteomics data define a broad panel of regulators of chemotaxis. Surprisingly, targets are almost exclusively other signaling proteins, rather than cytoskeletal components, revealing ErkB as a regulator of regulators rather than acting directly on the motility machinery. ErkB null cells migrate slowly and orientate poorly over broad dynamic ranges of chemoattractant. Our data indicate a central role for ErkB and its substrates in directing chemotaxis.
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Affiliation(s)
- John M E Nichols
- Cell Biology Division, MRC Laboratory of Molecular Biology, Francis Crick Avenue, Cambridge CB2 0QH, UK; MRC Laboratory for Molecular Cell Biology, University College London, Gower St., London WC1E 6BT, UK.
| | - Peggy Paschke
- Cell Biology Division, MRC Laboratory of Molecular Biology, Francis Crick Avenue, Cambridge CB2 0QH, UK; Cancer Research UK (CRUK) Beatson Institute, University of Glasgow, Bearsden, Glasgow G61 1BD, UK.
| | - Sew Peak-Chew
- Cell Biology Division, MRC Laboratory of Molecular Biology, Francis Crick Avenue, Cambridge CB2 0QH, UK
| | - Thomas D Williams
- Cell Biology Division, MRC Laboratory of Molecular Biology, Francis Crick Avenue, Cambridge CB2 0QH, UK
| | - Luke Tweedy
- Cancer Research UK (CRUK) Beatson Institute, University of Glasgow, Bearsden, Glasgow G61 1BD, UK
| | - Mark Skehel
- Cell Biology Division, MRC Laboratory of Molecular Biology, Francis Crick Avenue, Cambridge CB2 0QH, UK
| | - Elaine Stephens
- Cell Biology Division, MRC Laboratory of Molecular Biology, Francis Crick Avenue, Cambridge CB2 0QH, UK; Pfizer Inc, 1 Burtt Road, Andover, MA 01810, USA
| | - Jonathan R Chubb
- MRC Laboratory for Molecular Cell Biology and Department of Cell and Developmental Biology, University College London, Gower St., London WC1E 6BT, UK
| | - Robert R Kay
- Cell Biology Division, MRC Laboratory of Molecular Biology, Francis Crick Avenue, Cambridge CB2 0QH, UK.
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59
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Schumacher LJ. Neural crest migration with continuous cell states. J Theor Biol 2019; 481:84-90. [PMID: 30707976 DOI: 10.1016/j.jtbi.2019.01.029] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2018] [Revised: 01/24/2019] [Accepted: 01/28/2019] [Indexed: 01/09/2023]
Abstract
Models of cranial neural crest cell migration in cell-induced (or self-generated) gradients have included a division of labour into leader and follower migratory states, which undergo chemotaxis and contact guidance, respectively. Despite validated utility of these models through experimental perturbation of migration in the chick embryo and gene expression analysis showing relevant heterogeneity at the single cell level, an often raised question has been whether the discrete cell states are necessary, or if a continuum of cell behaviours offers a functionally equivalent description. Here we argue that this picture is supported by recent single-cell transcriptome data. Motivated by this, we implement two versions of a continuous-state model: (1) signal choice and (2) signal combination. We find that the cell population migrates further than in the discrete-state model and than in experimental observations. We further show that the signal combination model, but not the signal choice model, can be successfully adjusted to experimentally plausible regimes by reducing the chemoattractant consumption parameter. Thus we show an equivalently plausible, experimentally motivated, model of neural crest cell migration.
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Affiliation(s)
- Linus J Schumacher
- MCR Centre for Regenerative Medicine, University of Edinburgh, United Kingdom.
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60
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Schumacher L. Collective Cell Migration in Development. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2019; 1146:105-116. [PMID: 31612456 DOI: 10.1007/978-3-030-17593-1_7] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Collective cell migration is a key process in developmental biology, facilitating the bulk movement of cells in the morphogenesis of animal tissues. Predictive understanding in this field remains challenging due to the complexity of many interacting cells, their signalling, and microenvironmental factors - all of which can give rise to non-intuitive emergent behaviours. In this chapter we discuss biological examples of collective cell migration from a range of model systems, developmental stages, and spatial scales: border cell migration and haemocyte dispersal in Drosophila, gastrulation, neural crest migration, lateral line formation in zebrafish, and branching morphogenesis; as well as examples of developmental defects and similarities to metastatic invasion in cancer. These examples will be used to illustrate principles that we propose to be important: heterogeneity of cell states, substrate-free migration, contact-inhibition of locomotion, confinement and repulsive cues, cell-induced (or self-generated) gradients, stochastic group decisions, tissue mechanics, and reprogramming of cell behaviours. Understanding how such principles play a common, overarching role across multiple biological systems may lead towards a more integrative understanding of the causes and function of collective cell migration in developmental biology, and to potential strategies for the repair of developmental defects, the prevention and control of cancer, and advances in tissue engineering.
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Affiliation(s)
- Linus Schumacher
- MRC Centre for Regenerative Medicine, University of Edinburgh, Edinburgh, UK.
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61
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Papalazarou V, Salmeron-Sanchez M, Machesky LM. Tissue engineering the cancer microenvironment-challenges and opportunities. Biophys Rev 2018; 10:1695-1711. [PMID: 30406572 PMCID: PMC6297082 DOI: 10.1007/s12551-018-0466-8] [Citation(s) in RCA: 40] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2018] [Accepted: 10/15/2018] [Indexed: 12/25/2022] Open
Abstract
Mechanosensing is increasingly recognised as important for tumour progression. Tumours become stiff and the forces that normally balance in the healthy organism break down and become imbalanced, leading to increases in migration, invasion and metastatic dissemination. Here, we review recent advances in our understanding of how extracellular matrix properties, such as stiffness, viscoelasticity and architecture control cell behaviour. In addition, we discuss how the tumour microenvironment can be modelled in vitro, capturing these mechanical aspects, to better understand and develop therapies against tumour spread. We argue that by gaining a better understanding of the microenvironment and the mechanical forces that govern tumour dynamics, we can make advances in combatting cancer dormancy, recurrence and metastasis.
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Affiliation(s)
- Vassilis Papalazarou
- CRUK Beatson Institute for Cancer Research and Institute of cancer Sciences, University of Glasgow, Garscube Campus, Switchback Road, Bearsden, Glasgow, G61 1BD, UK
- The Centre for the Cellular Microenvironment, University of Glasgow, Glasgow, G12 8QQ, UK
| | | | - Laura M Machesky
- CRUK Beatson Institute for Cancer Research and Institute of cancer Sciences, University of Glasgow, Garscube Campus, Switchback Road, Bearsden, Glasgow, G61 1BD, UK.
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62
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Fort L, Batista JM, Thomason PA, Spence HJ, Whitelaw JA, Tweedy L, Greaves J, Martin KJ, Anderson KI, Brown P, Lilla S, Neilson MP, Tafelmeyer P, Zanivan S, Ismail S, Bryant DM, Tomkinson NCO, Chamberlain LH, Mastick GS, Insall RH, Machesky LM. Fam49/CYRI interacts with Rac1 and locally suppresses protrusions. Nat Cell Biol 2018; 20:1159-1171. [PMID: 30250061 PMCID: PMC6863750 DOI: 10.1038/s41556-018-0198-9] [Citation(s) in RCA: 52] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2017] [Accepted: 08/20/2018] [Indexed: 11/09/2022]
Abstract
Actin-based protrusions are reinforced through positive feedback, but it is unclear what restricts their size, or limits positive signals when they retract or split. We identify an evolutionarily conserved regulator of actin-based protrusion: CYRI (CYFIP-related Rac interactor) also known as Fam49 (family of unknown function 49). CYRI binds activated Rac1 via a domain of unknown function (DUF1394) shared with CYFIP, defining DUF1394 as a Rac1-binding module. CYRI-depleted cells have broad lamellipodia enriched in Scar/WAVE, but reduced protrusion-retraction dynamics. Pseudopods induced by optogenetic Rac1 activation in CYRI-depleted cells are larger and longer lived. Conversely, CYRI overexpression suppresses recruitment of active Scar/WAVE to the cell edge, resulting in short-lived, unproductive protrusions. CYRI thus focuses protrusion signals and regulates pseudopod complexity by inhibiting Scar/WAVE-induced actin polymerization. It thus behaves like a 'local inhibitor' as predicted in widely accepted mathematical models, but not previously identified in cells. CYRI therefore regulates chemotaxis, cell migration and epithelial polarization by controlling the polarity and plasticity of protrusions.
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Affiliation(s)
- Loic Fort
- CRUK Beatson Institute, Glasgow, UK
- University of Glasgow Institute of Cancer Sciences, Glasgow, UK
| | - José Miguel Batista
- CRUK Beatson Institute, Glasgow, UK
- University of Glasgow Institute of Cancer Sciences, Glasgow, UK
| | | | | | | | | | - Jennifer Greaves
- Strathclyde Institute of Pharmacy and Biomedical Sciences, University of Strathclyde, Glasgow, UK
| | | | - Kurt I Anderson
- CRUK Beatson Institute, Glasgow, UK
- Francis Crick Institute, London, UK
| | | | | | | | | | | | - Shehab Ismail
- CRUK Beatson Institute, Glasgow, UK
- University of Glasgow Institute of Cancer Sciences, Glasgow, UK
| | - David M Bryant
- CRUK Beatson Institute, Glasgow, UK
- University of Glasgow Institute of Cancer Sciences, Glasgow, UK
| | - Nicholas C O Tomkinson
- WestCHEM, Department of Pure and Applied Chemistry, University of Strathclyde, Glasgow, UK
| | - Luke H Chamberlain
- Strathclyde Institute of Pharmacy and Biomedical Sciences, University of Strathclyde, Glasgow, UK
| | | | - Robert H Insall
- CRUK Beatson Institute, Glasgow, UK.
- University of Glasgow Institute of Cancer Sciences, Glasgow, UK.
| | - Laura M Machesky
- CRUK Beatson Institute, Glasgow, UK.
- University of Glasgow Institute of Cancer Sciences, Glasgow, UK.
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63
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Heinrich D, Barnett R, Tweedy L, Insall R, Stallforth P, Winckler T. The Chemoattractant Glorin Is Inactivated by Ester Cleavage during Early Multicellular Development of Polysphondylium pallidum. ACS Chem Biol 2018; 13:1506-1513. [PMID: 29792671 DOI: 10.1021/acschembio.8b00046] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Among the amoebozoan species capable of forming fruiting bodies, the dictyostelid social amoebae stand out since they form true multicellular organisms by means of single cell aggregation. Upon food depletion, cells migrate across gradients of extracellular signals initiated by cells in aggregation centers. The model species that is widely used to study multicellular development of social amoebae, Dictyostelium discoideum, uses cyclic adenosine monophosphate (cAMP) as a chemoattractant to coordinate aggregation. Molecular phylogeny studies suggested that social amoebae evolved in four major groups, of which groups 1 and 2 are paraphyletic to groups 3 and 4. During early development, intercellular communication with cAMP appears to be restricted to group 4 species. Cells of group 1 and 2 taxa do not respond chemotactically to extracellular cAMP and likely use a dipeptide chemoattractant known as glorin ( N-propionyl-γ-L-glutamyl-L-ornithin-δ-lactam-ethylester) to regulate aggregation. Directional migration of glorin-responsive cells requires the periodic breakdown of the chemoattractant. Here, we identified an extracellular enzymatic activity (glorinase) in the glorin-responsive group 2 taxon Polysphondylium pallidum leading to the inactivation of glorin. We determined the inactivation mechanism to proceed via hydrolytic ethyl ester cleavage of the γ-glutamyl moiety of glorin. Synthetic glorinamide, in which the ethyl ester group was substituted by an ethyl amide group, had glorin-like biological activity but was resistant to degradation by glorinase. Our observations pave the way for future investigations toward an ancient eukaryotic chemotaxis system.
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Affiliation(s)
- Daniel Heinrich
- Pharmaceutical Biology, Institute of Pharmacy , Friedrich Schiller University , Jena , Germany
| | - Robert Barnett
- Junior Research Group 'Chemistry of Microbial Communication' , Leibniz Institute for Natural Product Research and Infection Biology - Hans Knöll Institute , Jena , Germany
| | - Luke Tweedy
- Cancer Research UK Beatson Institute , Glasgow , United Kingdom
| | - Robert Insall
- Cancer Research UK Beatson Institute , Glasgow , United Kingdom
| | - Pierre Stallforth
- Junior Research Group 'Chemistry of Microbial Communication' , Leibniz Institute for Natural Product Research and Infection Biology - Hans Knöll Institute , Jena , Germany
| | - Thomas Winckler
- Pharmaceutical Biology, Institute of Pharmacy , Friedrich Schiller University , Jena , Germany
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64
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Camley BA. Collective gradient sensing and chemotaxis: modeling and recent developments. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2018; 30:223001. [PMID: 29644981 PMCID: PMC6252055 DOI: 10.1088/1361-648x/aabd9f] [Citation(s) in RCA: 26] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/05/2023]
Abstract
Cells measure a vast variety of signals, from their environment's stiffness to chemical concentrations and gradients; physical principles strongly limit how accurately they can do this. However, when many cells work together, they can cooperate to exceed the accuracy of any single cell. In this topical review, I will discuss the experimental evidence showing that cells collectively sense gradients of many signal types, and the models and physical principles involved. I also propose new routes by which experiments and theory can expand our understanding of these problems.
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Affiliation(s)
- Brian A Camley
- Departments of Physics & Astronomy and Biophysics, Johns Hopkins University, Baltimore, MD, United States of America
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65
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Fu X, Kato S, Long J, Mattingly HH, He C, Vural DC, Zucker SW, Emonet T. Spatial self-organization resolves conflicts between individuality and collective migration. Nat Commun 2018; 9:2177. [PMID: 29872053 PMCID: PMC5988668 DOI: 10.1038/s41467-018-04539-4] [Citation(s) in RCA: 53] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2017] [Accepted: 05/03/2018] [Indexed: 12/24/2022] Open
Abstract
Collective behavior can spontaneously emerge when individuals follow common rules of interaction. However, the behavior of each individual differs due to existing genetic and non-genetic variation within the population. It remains unclear how this individuality is managed to achieve collective behavior. We quantify individuality in bands of clonal Escherichia coli cells that migrate collectively along a channel by following a self-generated gradient of attractant. We discover that despite substantial differences in individual chemotactic abilities, the cells are able to migrate as a coherent group by spontaneously sorting themselves within the moving band. This sorting mechanism ensures that differences between individual chemotactic abilities are compensated by differences in the local steepness of the traveling gradient each individual must navigate, and determines the minimum performance required to travel with the band. By resolving conflicts between individuality and collective migration, this mechanism enables populations to maintain advantageous diversity while on the move. How bacteria migrate collectively despite individual phenotypic variation is not understood. Here, the authors show that cells spontaneously sort themselves within moving bands such that variations in individual tumble bias, a determinant of gradient climbing speed, are compensated by the local gradient steepness experienced by individuals.
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Affiliation(s)
- X Fu
- Department of Molecular, Cellular, and Developmental Biology, Yale University, New Haven, CT, 06520, USA.,Institute of Synthetic Biology, Shenzhen Institutes of Advanced Technology, Chinese Academy of Sciences, Shenzhen, 518055, China
| | - S Kato
- Department of Molecular, Cellular, and Developmental Biology, Yale University, New Haven, CT, 06520, USA.,Department of Molecular Biotechnology, Graduate School of Advanced Sciences of Matter, Hiroshima University, Higashi-Hiroshima, Hiroshima, 739-8530, Japan
| | - J Long
- Department of Molecular, Cellular, and Developmental Biology, Yale University, New Haven, CT, 06520, USA.,Department of Physics, Yale University, New Haven, CT, 06520, USA
| | - H H Mattingly
- Department of Molecular, Cellular, and Developmental Biology, Yale University, New Haven, CT, 06520, USA
| | - C He
- Institute of Synthetic Biology, Shenzhen Institutes of Advanced Technology, Chinese Academy of Sciences, Shenzhen, 518055, China
| | - D C Vural
- Department of Molecular, Cellular, and Developmental Biology, Yale University, New Haven, CT, 06520, USA.,Department of Physics, University of Notre Dame, Notre Dame, IN, 46556, USA
| | - S W Zucker
- Department of Computer Science, Yale University, New Haven, CT, 06520, USA.,Department of Biomedical Engineering, Yale University, New Haven, CT, 06520, USA
| | - T Emonet
- Department of Molecular, Cellular, and Developmental Biology, Yale University, New Haven, CT, 06520, USA. .,Department of Physics, Yale University, New Haven, CT, 06520, USA.
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66
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Zinn-Björkman L, Adler FR. Modeling factors that regulate cell cooperativity in the zebrafish posterior lateral line primordium. J Theor Biol 2018; 444:93-99. [PMID: 29470991 DOI: 10.1016/j.jtbi.2018.02.009] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2017] [Revised: 02/09/2018] [Accepted: 02/12/2018] [Indexed: 01/10/2023]
Abstract
Collective cell migration is an integral part of organismal development. We consider migration of the zebrafish primordium during development of the posterior lateral line, a sensory system that detects water movement patterns. Experiments have shown that the chemokine ligand CXCL12a and its receptors CXCR4b and CXCR7b are key players for driving migration of the primordium, while FGF signaling helps maintain cohesion. In this work, we formulate a mathematical model of a laser ablated primordium separated into two smaller cell collectives: a leading collective that responds to local CXCL12a levels and a trailing collective that migrates up a local FGF gradient. Our model replicates recent experimental results, while also predicting a "runaway" behavior when FGF gradient response is inhibited. We also use our model to estimate diffusion coefficients of CXCL12a and FGF in the lateral line.
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Affiliation(s)
- Leif Zinn-Björkman
- Department of Mathematics, University of Utah, Salt Lake City, UT 84112, United States.
| | - Frederick R Adler
- Department of Mathematics, University of Utah, Salt Lake City, UT 84112, United States; School of Biology, University of Utah, Salt Lake City, UT 84112, United States
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67
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Giurghita D, Husmeier D. Statistical modelling of cell movement. STAT NEERL 2018. [DOI: 10.1111/stan.12140] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Diana Giurghita
- School of Mathematics and Statistics; University of Glasgow; Glasgow G12 8QQ UK
| | - Dirk Husmeier
- School of Mathematics and Statistics; University of Glasgow; Glasgow G12 8QQ UK
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68
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De Bellard ME, Ortega B, Sao S, Kim L, Herman J, Zuhdi N. Neuregulin-1 is a chemoattractant and chemokinetic molecule for trunk neural crest cells. Dev Dyn 2018. [PMID: 29516589 DOI: 10.1002/dvdy.24625] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
BACKGROUND Trunk neural crest cells migrate rapidly along characteristic pathways within the developing vertebrate embryo. Proper trunk neural crest cell migration is necessary for the morphogenesis of much of the peripheral nervous system, melanocytes, and the adrenal medulla. Numerous molecules help guide trunk neural crest cell migration throughout the early embryo. RESULTS The trophic factor NRG1 is a chemoattractant through in vitro chemotaxis assays and in vivo silencing via a DN-erbB receptor. Interestingly, we also observed changes in migratory responses consistent with a chemokinetic effect of NRG1 in trunk neural crest velocity. CONCLUSIONS NRG1 is a trunk neural crest cell chemoattractant and chemokinetic molecule. Developmental Dynamics 247:888-902, 2018.. © 2018 Wiley Periodicals, Inc.
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Affiliation(s)
| | - Blanca Ortega
- Biology Department, California State University Northridge, Northridge, California
| | - Sothy Sao
- Biology Department, California State University Northridge, Northridge, California
| | - Lino Kim
- Biology Department, California State University Northridge, Northridge, California
| | - Joshua Herman
- Biology Department, California State University Northridge, Northridge, California
| | - Nora Zuhdi
- Biology Department, California State University Northridge, Northridge, California
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69
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Meena NP, Kimmel AR. Quantification of Live Bacterial Sensing for Chemotaxis and Phagocytosis and of Macropinocytosis. Front Cell Infect Microbiol 2018; 8:62. [PMID: 29552545 PMCID: PMC5840232 DOI: 10.3389/fcimb.2018.00062] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2017] [Accepted: 02/13/2018] [Indexed: 01/26/2023] Open
Abstract
Initial immunological defense mechanisms to pathogen invasion rely on innate pathways of chemotaxis and phagocytosis, original to ancient phagocytes. Although chemotaxis has been well-studied in mammalian and model systems using purified chemoattractants in defined conditions, directed movement toward live bacteria has been more difficult to assess. Dictyostelium discoideum is a professional phagocyte that chemotaxes toward bacteria during growth-phase in a process to locate nutrient sources. Using Dictyostelium as a model, we have developed a system that is able to quantify chemotaxis to very high sensitivity. Here, Dictyostelium can detect various chemoattractants at concentrations <1 nM. Given this exceedingly sensitive signal response, Dictyostelium will migrate directionally toward live gram positive and gram negative bacteria, in a highly quantifiable manner, and dependent upon bacterially-secreted chemoattractants. Additionally, we have developed a real-time, quantitative assay for phagocytosis of live gram positive and gram negative bacteria. To extend the analyses of endocytic functions, we further modified the system to quantify cellular uptake via macropinocytosis of smaller (<100 kDa) molecules. These various approaches provide novel means to dissect potential for identification of novel chemoattractants and mechanistic factors that are essential for chemotaxis, phagocytosis, and/or macropinocytosis and for more detailed understanding in host-pathogen interactive defenses.
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Affiliation(s)
- Netra P Meena
- Laboratory of Cellular and Developmental Biology, National Institute of Diabetes and Digestive and Kidney Diseases, The National Institutes of Health, Bethesda, MD, United States
| | - Alan R Kimmel
- Laboratory of Cellular and Developmental Biology, National Institute of Diabetes and Digestive and Kidney Diseases, The National Institutes of Health, Bethesda, MD, United States
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70
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Wang X, Chen D. Purinergic Regulation of Neutrophil Function. Front Immunol 2018; 9:399. [PMID: 29545806 PMCID: PMC5837999 DOI: 10.3389/fimmu.2018.00399] [Citation(s) in RCA: 75] [Impact Index Per Article: 12.5] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2018] [Accepted: 02/13/2018] [Indexed: 12/28/2022] Open
Abstract
Purinergic signaling, which utilizes nucleotides (particularly ATP) and adenosine as transmitter molecules, plays an essential role in immune system. In the extracellular compartment, ATP predominantly functions as a pro-inflammatory molecule through activation of P2 receptors, whereas adenosine mostly functions as an anti-inflammatory molecule through activation of P1 receptors. Neutrophils are the most abundant immune cells in circulation and have emerged as an important component in orchestrating a complex series of events during inflammation. However, because of the destructive nature of neutrophil-derived inflammatory agents, neutrophil activation is fine-tuned, and purinergic signaling is intimately involved in this process. Indeed, shifting the balance between P2 and P1 signaling is critical for neutrophils to appropriately exert their immunologic activity. Here, we review the role of purinergic signaling in regulating neutrophil function, and discuss the potential of targeting purinergic signaling for the treatment of neutrophil-associated infectious and inflammatory diseases.
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Affiliation(s)
- Xu Wang
- Institute of Oncology, Affiliated Hospital of Jiangsu University, Zhenjiang, China
| | - Deyu Chen
- Institute of Oncology, Affiliated Hospital of Jiangsu University, Zhenjiang, China
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71
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Susanto O, Insall RH. LPP3, LPA and self-generated chemotactic gradients in biomedical science. Commun Integr Biol 2018. [PMCID: PMC5824962 DOI: 10.1080/19420889.2017.1398870] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022] Open
Abstract
Chemotaxis is a major driver of cancer spread, but in most cases we do not know where gradients of attractant come from. In the case of melanoma, chemotaxis to LPA is an important driver of metastasis, and the gradients are made by the tumour cells themselves, by locally breaking down ambient LPA. We have now made a general assay for self-generated chemotaxis, and used it to show that the enzyme LPP3 is responsible for breaking down LPA and thus creating the gradients. Further analysis shows LPP3 is important in several invasion assays, in particular 3D ones in which cells spread outwards through matrix. The new assays will illuminate where physiological self-generated gradients occur; we believe they will be common throughout biology and pathology.
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Affiliation(s)
- Olivia Susanto
- CR-UK Beatson Institute, Switchback Road, Glasgow G61 1BD, UK
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72
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Segota I, Franck C. Extracellular Processing of Molecular Gradients by Eukaryotic Cells Can Improve Gradient Detection Accuracy. PHYSICAL REVIEW LETTERS 2017; 119:248101. [PMID: 29286727 DOI: 10.1103/physrevlett.119.248101] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/26/2017] [Indexed: 06/07/2023]
Abstract
Eukaryotic cells sense molecular gradients by measuring spatial concentration variation through the difference in the number of occupied receptors to which molecules can bind. They also secrete enzymes that degrade these molecules, and it is presently not well understood how this affects the local gradient perceived by cells. Numerical and analytical results show that these enzymes can substantially increase the signal-to-noise ratio of the receptor difference and allow cells to respond to a much broader range of molecular concentrations and gradients than they would without these enzymes.
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Affiliation(s)
- Igor Segota
- Laboratory of Atomic and Solid State Physics, Cornell University, Ithaca 14853, USA
| | - Carl Franck
- Laboratory of Atomic and Solid State Physics, Cornell University, Ithaca 14853, USA
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73
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Dalle Nogare D, Chitnis AB. A framework for understanding morphogenesis and migration of the zebrafish posterior Lateral Line primordium. Mech Dev 2017; 148:69-78. [PMID: 28460893 PMCID: PMC10993927 DOI: 10.1016/j.mod.2017.04.005] [Citation(s) in RCA: 31] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2017] [Accepted: 04/18/2017] [Indexed: 12/31/2022]
Abstract
A description of zebrafish posterior Lateral Line (pLL) primordium development at single cell resolution together with the dynamics of Wnt, FGF, Notch and chemokine signaling in this system has allowed us to develop a framework to understand the self-organization of cell fate, morphogenesis and migration during its early development. The pLL primordium migrates under the skin, from near the ear to the tip of the tail, periodically depositing neuromasts. Nascent neuromasts, or protoneuromasts, form sequentially within the migrating primordium, mature, and are deposited from its trailing end. Initially broad Wnt signaling inhibits protoneuromast formation. However, protoneuromasts form sequentially in response to FGF signaling, starting from the trailing end, in the wake of a progressively shrinking Wnt system. While proliferation adds to the number of cells, the migrating primordium progressively shrinks as its trailing cells stop moving and are deposited. As it shrinks, the length of the migrating primordium correlates with the length of the leading Wnt system. Based on these observations we show how measuring the rate at which the Wnt system shrinks, the proliferation rate, the initial size of the primordium, its speed, and a few additional parameters allows us to predict the pattern of neuromast formation and deposition by the migrating primordium in both wild-type and mutant contexts. While the mechanism that links the length of the leading Wnt system to that of the primordium remains unclear, we discuss how it might be determined by access to factors produced in the leading Wnt active zone that are required for collective migration of trailing cells. We conclude by reviewing how FGFs, produced in response to Wnt signaling in leading cells, help determine collective migration of trailing cells, while a polarized response to a self-generated chemokine gradient serves as an efficient mechanism to steer primordium migration along its relatively long journey.
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Affiliation(s)
- Damian Dalle Nogare
- Section on Neural Developmental Dynamics, Division of Developmental Biology, Eunice Kennedy Shriver National Institute of Child Health and Human Development, Bethesda, MD, USA
| | - Ajay B Chitnis
- Section on Neural Developmental Dynamics, Division of Developmental Biology, Eunice Kennedy Shriver National Institute of Child Health and Human Development, Bethesda, MD, USA.
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74
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Susanto O, Koh YWH, Morrice N, Tumanov S, Thomason PA, Nielson M, Tweedy L, Muinonen-Martin AJ, Kamphorst JJ, Mackay GM, Insall RH. LPP3 mediates self-generation of chemotactic LPA gradients by melanoma cells. J Cell Sci 2017; 130:3455-3466. [PMID: 28871044 PMCID: PMC5665449 DOI: 10.1242/jcs.207514] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2017] [Accepted: 08/18/2017] [Indexed: 12/11/2022] Open
Abstract
Melanoma cells steer out of tumours using self-generated lysophosphatidic acid (LPA) gradients. The cells break down LPA, which is present at high levels around the tumours, creating a dynamic gradient that is low in the tumour and high outside. They then migrate up this gradient, creating a complex and evolving outward chemotactic stimulus. Here, we introduce a new assay for self-generated chemotaxis, and show that raising LPA levels causes a delay in migration rather than loss of chemotactic efficiency. Knockdown of the lipid phosphatase LPP3 - but not of its homologues LPP1 or LPP2 - diminishes the cell's ability to break down LPA. This is specific for chemotactically active LPAs, such as the 18:1 and 20:4 species. Inhibition of autotaxin-mediated LPA production does not diminish outward chemotaxis, but loss of LPP3-mediated LPA breakdown blocks it. Similarly, in both 2D and 3D invasion assays, knockdown of LPP3 diminishes the ability of melanoma cells to invade. Our results demonstrate that LPP3 is the key enzyme in the breakdown of LPA by melanoma cells, and confirm the importance of attractant breakdown in LPA-mediated cell steering.This article has an associated First Person interview with the first author of the paper.
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Affiliation(s)
- Olivia Susanto
- Beatson Institute for Cancer Research, Garscube Estate, Switchback Road, Bearsden, Glasgow G61 1BD, UK
| | - Yvette W H Koh
- Beatson Institute for Cancer Research, Garscube Estate, Switchback Road, Bearsden, Glasgow G61 1BD, UK
| | - Nick Morrice
- Beatson Institute for Cancer Research, Garscube Estate, Switchback Road, Bearsden, Glasgow G61 1BD, UK
| | - Sergey Tumanov
- Beatson Institute for Cancer Research, Garscube Estate, Switchback Road, Bearsden, Glasgow G61 1BD, UK
- Institute of Cancer Sciences, University of Glasgow, Garscube Estate, Switchback Road, Bearsden, Glasgow G61 1BD, UK
| | - Peter A Thomason
- Beatson Institute for Cancer Research, Garscube Estate, Switchback Road, Bearsden, Glasgow G61 1BD, UK
| | - Matthew Nielson
- Beatson Institute for Cancer Research, Garscube Estate, Switchback Road, Bearsden, Glasgow G61 1BD, UK
| | - Luke Tweedy
- Beatson Institute for Cancer Research, Garscube Estate, Switchback Road, Bearsden, Glasgow G61 1BD, UK
| | - Andrew J Muinonen-Martin
- York Teaching Hospital NHS Foundation Trust, The York Hospital, York YO31 8HE, UK
- Leeds Cancer Centre - Melanoma Institute, Bexley Wing, St James's University Hospital, Beckett Street, Leeds LS9 7TF, UK
| | - Jurre J Kamphorst
- Beatson Institute for Cancer Research, Garscube Estate, Switchback Road, Bearsden, Glasgow G61 1BD, UK
- Institute of Cancer Sciences, University of Glasgow, Garscube Estate, Switchback Road, Bearsden, Glasgow G61 1BD, UK
| | - Gillian M Mackay
- Beatson Institute for Cancer Research, Garscube Estate, Switchback Road, Bearsden, Glasgow G61 1BD, UK
| | - Robert H Insall
- Beatson Institute for Cancer Research, Garscube Estate, Switchback Road, Bearsden, Glasgow G61 1BD, UK
- Institute of Cancer Sciences, University of Glasgow, Garscube Estate, Switchback Road, Bearsden, Glasgow G61 1BD, UK
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75
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Svensson CM, Medyukhina A, Belyaev I, Al-Zaben N, Figge MT. Untangling cell tracks: Quantifying cell migration by time lapse image data analysis. Cytometry A 2017; 93:357-370. [DOI: 10.1002/cyto.a.23249] [Citation(s) in RCA: 39] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Affiliation(s)
- Carl-Magnus Svensson
- Applied Systems Biology, Leibniz Institute for Natural Product Research and Infection Biology, Hans Knöll Institute (HKI); Jena Germany
| | - Anna Medyukhina
- Applied Systems Biology, Leibniz Institute for Natural Product Research and Infection Biology, Hans Knöll Institute (HKI); Jena Germany
| | - Ivan Belyaev
- Applied Systems Biology, Leibniz Institute for Natural Product Research and Infection Biology, Hans Knöll Institute (HKI); Jena Germany
- Friedrich Schiller University; Jena Germany
| | - Naim Al-Zaben
- Applied Systems Biology, Leibniz Institute for Natural Product Research and Infection Biology, Hans Knöll Institute (HKI); Jena Germany
- Friedrich Schiller University; Jena Germany
| | - Marc Thilo Figge
- Applied Systems Biology, Leibniz Institute for Natural Product Research and Infection Biology, Hans Knöll Institute (HKI); Jena Germany
- Friedrich Schiller University; Jena Germany
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76
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Tasaki S, Nakayama M, Shoji W. Morphologies of Bacillus subtilis communities responding to environmental variation. Dev Growth Differ 2017; 59:369-378. [PMID: 28675458 DOI: 10.1111/dgd.12383] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2017] [Revised: 05/24/2017] [Accepted: 06/06/2017] [Indexed: 12/20/2022]
Abstract
Bacterial communities exhibit a variety of growth morphologies in constructing robust systems under different environmental conditions. We review the diverse morphologies of Bacillus subtilis communities and their mechanisms of self-organization. B. subtilis uses different cell types to suit environmental conditions and cell density. The subpopulation of each cell type exhibits various environment-sensitive properties. Furthermore, division of labor among the subpopulations results in flexible development for the community as a whole. We review how B. subtilis community morphologies and growth strategies respond to environmental perturbations.
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Affiliation(s)
- Sohei Tasaki
- Frontier Research Institute for Interdisciplinary Sciences (FRIS), Tohoku University, 6-3 Aramaki-aza-Aoba, Aoba-ku, Japan.,Graduate School of Science, Tohoku University, 6-3 Aramaki-aza-Aoba, Aoba-ku, Japan
| | - Madoka Nakayama
- Sendai National College of Technology, 48 Nodayama, Medeshima-Shiote, Natori, Miyagi, 981-1239, Japan
| | - Wataru Shoji
- Frontier Research Institute for Interdisciplinary Sciences (FRIS), Tohoku University, 6-3 Aramaki-aza-Aoba, Aoba-ku, Japan.,Institute of Development, Aging and Cancer, Tohoku University, 1 Seiryo-machi, Aoba-ku, Sendai, Miyagi, 980-8575, Japan
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77
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Hasan D, Blankman P, Nieman GF. Purinergic signalling links mechanical breath profile and alveolar mechanics with the pro-inflammatory innate immune response causing ventilation-induced lung injury. Purinergic Signal 2017; 13:363-386. [PMID: 28547381 PMCID: PMC5563293 DOI: 10.1007/s11302-017-9564-5] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2017] [Accepted: 04/26/2017] [Indexed: 02/06/2023] Open
Abstract
Severe pulmonary infection or vigorous cyclic deformation of the alveolar epithelial type I (AT I) cells by mechanical ventilation leads to massive extracellular ATP release. High levels of extracellular ATP saturate the ATP hydrolysis enzymes CD39 and CD73 resulting in persistent high ATP levels despite the conversion to adenosine. Above a certain level, extracellular ATP molecules act as danger-associated molecular patterns (DAMPs) and activate the pro-inflammatory response of the innate immunity through purinergic receptors on the surface of the immune cells. This results in lung tissue inflammation, capillary leakage, interstitial and alveolar oedema and lung injury reducing the production of surfactant by the damaged AT II cells and deactivating the surfactant function by the concomitant extravasated serum proteins through capillary leakage followed by a substantial increase in alveolar surface tension and alveolar collapse. The resulting inhomogeneous ventilation of the lungs is an important mechanism in the development of ventilation-induced lung injury. The high levels of extracellular ATP and the upregulation of ecto-enzymes and soluble enzymes that hydrolyse ATP to adenosine (CD39 and CD73) increase the extracellular adenosine levels that inhibit the innate and adaptive immune responses rendering the host susceptible to infection by invading microorganisms. Moreover, high levels of extracellular adenosine increase the expression, the production and the activation of pro-fibrotic proteins (such as TGF-β, α-SMA, etc.) followed by the establishment of lung fibrosis.
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Affiliation(s)
- Djo Hasan
- Department of Adult ICU, University Hospital Erasmus MC Rotterdam, 's-Gravendijkwal 230 3015 CE, Rotterdam, the Netherlands.
| | - Paul Blankman
- Department of Adult ICU, University Hospital Erasmus MC Rotterdam, 's-Gravendijkwal 230 3015 CE, Rotterdam, the Netherlands
| | - Gary F Nieman
- Department of Surgery, Upstate Medical University, 750 E Adams St, Syracuse, NY, 13210, USA
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78
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Heinrich V, Simpson WD, Francis EA. Analytical Prediction of the Spatiotemporal Distribution of Chemoattractants around Their Source: Theory and Application to Complement-Mediated Chemotaxis. Front Immunol 2017; 8:578. [PMID: 28603522 PMCID: PMC5445147 DOI: 10.3389/fimmu.2017.00578] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2017] [Accepted: 05/01/2017] [Indexed: 11/13/2022] Open
Abstract
The ability of motile immune cells to detect and follow gradients of chemoattractant is critical to numerous vital functions, including their recruitment to sites of infection and-in emerging immunotherapeutic applications-to malignant tumors. Facilitated by a multitude of chemotactic receptors, the cells navigate a maze of stimuli to home in on their target. Distinct chemotactic processes direct this navigation at particular times and cell-target distances. The expedient coordination of this spatiotemporal hierarchy of chemotactic stages is the central element of a key paradigm of immunotaxis. Understanding this hierarchy is an enormous interdisciplinary challenge that requires, among others, quantitative insight into the shape, range, and dynamics of the profiles of chemoattractants around their sources. We here present a closed-form solution to a diffusion-reaction problem that describes the evolution of the concentration gradient of chemoattractant under various conditions. Our ready-to-use mathematical prescription captures many biological situations reasonably well and can be explored with standard graphing software, making it a valuable resource for every researcher studying chemotaxis. We here apply this mathematical model to characterize the chemoattractant cloud of anaphylatoxins that forms around bacterial and fungal pathogens in the presence of host serum. We analyze the spatial reach, rate of formation, and rate of dispersal of this locator cloud under realistic physiological conditions. Our analysis predicts that simply being small is an effective protective strategy of pathogens against complement-mediated discovery by host immune cells over moderate-to-large distances. Leveraging our predictions against single-cell, pure-chemotaxis experiments that use human immune cells as biosensors, we are able to explain the limited distance over which the cells recognize microbes. We conclude that complement-mediated chemotaxis is a universal, but short-range, homing mechanism by which chemotaxing immune cells can implement a last-minute course correction toward pathogenic microbes. Thus, the integration of theory and experiments provides a sound mechanistic explanation of the primary role of complement-mediated chemotaxis within the hierarchy of immunotaxis, and why other chemotactic processes are required for the successful recruitment of immune cells over large distances.
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Affiliation(s)
- Volkmar Heinrich
- Department of Biomedical Engineering, University of California at Davis, Davis, CA, United States
| | - Wooten D Simpson
- Department of Biomedical Engineering, University of California at Davis, Davis, CA, United States
| | - Emmet A Francis
- Department of Biomedical Engineering, University of California at Davis, Davis, CA, United States
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79
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Meena NP, Kimmel AR. Chemotactic network responses to live bacteria show independence of phagocytosis from chemoreceptor sensing. eLife 2017; 6. [PMID: 28541182 PMCID: PMC5476428 DOI: 10.7554/elife.24627] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2016] [Accepted: 05/24/2017] [Indexed: 12/21/2022] Open
Abstract
Aspects of innate immunity derive from characteristics inherent to phagocytes, including chemotaxis toward and engulfment of unicellular organisms or cell debris. Ligand chemotaxis has been biochemically investigated using mammalian and model systems, but precision of chemotaxis towards ligands being actively secreted by live bacteria is not well studied, nor has there been systematic analyses of interrelationships between chemotaxis and phagocytosis. The genetic/molecular model Dictyostelium and mammalian phagocytes share mechanistic pathways for chemotaxis and phagocytosis; Dictyostelium chemotax toward bacteria and phagocytose them as food sources. We quantified Dictyostelium chemotaxis towards live gram positive and gram negative bacteria and demonstrate high sensitivity to multiple bacterially-secreted chemoattractants. Additive/competitive assays indicate that intracellular signaling-networks for multiple ligands utilize independent upstream adaptive mechanisms, but common downstream targets, thus amplifying detection at low signal propagation, but strengthening discrimination of multiple inputs. Finally, analyses of signaling-networks for chemotaxis and phagocytosis indicate that chemoattractant receptor-signaling is not essential for bacterial phagocytosis. DOI:http://dx.doi.org/10.7554/eLife.24627.001
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Affiliation(s)
- Netra Pal Meena
- Laboratory of Cellular and Developmental Biology, National Institute of Diabetes and Digestive and Kidney Diseases, The National Institutes of Health, Bethesda, United States
| | - Alan R Kimmel
- Laboratory of Cellular and Developmental Biology, National Institute of Diabetes and Digestive and Kidney Diseases, The National Institutes of Health, Bethesda, United States
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80
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De Palo G, Yi D, Endres RG. A critical-like collective state leads to long-range cell communication in Dictyostelium discoideum aggregation. PLoS Biol 2017; 15:e1002602. [PMID: 28422986 PMCID: PMC5396852 DOI: 10.1371/journal.pbio.1002602] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2016] [Accepted: 03/23/2017] [Indexed: 11/19/2022] Open
Abstract
The transition from single-cell to multicellular behavior is important in early development but rarely studied. The starvation-induced aggregation of the social amoeba Dictyostelium discoideum into a multicellular slug is known to result from single-cell chemotaxis towards emitted pulses of cyclic adenosine monophosphate (cAMP). However, how exactly do transient, short-range chemical gradients lead to coherent collective movement at a macroscopic scale? Here, we developed a multiscale model verified by quantitative microscopy to describe behaviors ranging widely from chemotaxis and excitability of individual cells to aggregation of thousands of cells. To better understand the mechanism of long-range cell—cell communication and hence aggregation, we analyzed cell—cell correlations, showing evidence of self-organization at the onset of aggregation (as opposed to following a leader cell). Surprisingly, cell collectives, despite their finite size, show features of criticality known from phase transitions in physical systems. By comparing wild-type and mutant cells with impaired aggregation, we found the longest cell—cell communication distance in wild-type cells, suggesting that criticality provides an adaptive advantage and optimally sized aggregates for the dispersal of spores. A multiscale model and imaging data show that cells of the slime mold Dictyostelium discoideum maximize their cell—cell communication range during aggregation by a critical-like state known from phase transitions in physical systems. Cells are often coupled to each other in cell collectives, such as aggregates during early development, tissues in the developed organism, and tumors in disease. How do cells communicate over macroscopic distances much larger than the typical cell—cell distance to decide how they should behave? Here, we developed a multiscale model of social amoeba, spanning behavior from individuals to thousands of cells. We show that local cell—cell coupling via secreted chemicals may be tuned to a critical value, resulting in emergent long-range communication and heightened sensitivity. Hence, these aggregates are remarkably similar to bacterial biofilms and neuronal networks, all communicating in a pulselike fashion. Similar organizing principles may also aid our understanding of the remarkable robustness in cancer development.
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Affiliation(s)
- Giovanna De Palo
- Department of Life Sciences, Imperial College London, London, United Kingdom
- Centre for Integrative Systems Biology and Bioinformatics, Imperial College London, London, United Kingdom
| | - Darvin Yi
- Joseph Henry Laboratories of Physics, Princeton University, Princeton, New Jersey, United States of America
- Lewis Siegler Institute for Integrative Genomics, Princeton University, Princeton, New Jersey, United States of America
| | - Robert G. Endres
- Department of Life Sciences, Imperial College London, London, United Kingdom
- Centre for Integrative Systems Biology and Bioinformatics, Imperial College London, London, United Kingdom
- * E-mail:
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81
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Abstract
Cell polarization is a key step in the migration, development, and organization of eukaryotic cells, both at the single cell and multicellular level. Research on the mechanisms that give rise to polarization of a given cell, and organization of polarity within a tissue has led to new understanding across cellular and developmental biology. In this review, we describe some of the history of theoretical and experimental aspects of the field, as well as some interesting questions and challenges for the future.
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Affiliation(s)
- Wouter-Jan Rappel
- Department of Physics, University of California, San Diego, La Jolla, USA
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82
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Self-organization of bacterial communities against environmental pH variation: Controlled chemotactic motility arranges cell population structures in biofilms. PLoS One 2017; 12:e0173195. [PMID: 28253348 PMCID: PMC5333884 DOI: 10.1371/journal.pone.0173195] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2016] [Accepted: 02/16/2017] [Indexed: 11/19/2022] Open
Abstract
As with many living organisms, bacteria often live on the surface of solids, such as foods, organisms, buildings and soil. Compared with dispersive behavior in liquid, bacteria on surface environment exhibit significantly restricted mobility. They have access to only limited resources and cannot be liberated from the changing environment. Accordingly, appropriate collective strategies are necessarily required for long-term growth and survival. However, in spite of our deepening knowledge of the structure and characteristics of individual cells, strategic self-organizing dynamics of their community is poorly understood and therefore not yet predictable. Here, we report a morphological change in Bacillus subtilis biofilms due to environmental pH variations, and present a mathematical model for the macroscopic spatio-temporal dynamics. We show that an environmental pH shift transforms colony morphology on hard agar media from notched 'volcano-like' to round and front-elevated 'crater-like'. We discover that a pH-dependent dose-response relationship between nutritional resource level and quantitative bacterial motility at the population level plays a central role in the mechanism of the spatio-temporal cell population structure design in biofilms.
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83
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Camley BA, Rappel WJ. Physical models of collective cell motility: from cell to tissue. JOURNAL OF PHYSICS D: APPLIED PHYSICS 2017; 50:113002. [PMID: 28989187 PMCID: PMC5625300 DOI: 10.1088/1361-6463/aa56fe] [Citation(s) in RCA: 96] [Impact Index Per Article: 13.7] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/21/2023]
Abstract
In this article, we review physics-based models of collective cell motility. We discuss a range of techniques at different scales, ranging from models that represent cells as simple self-propelled particles to phase field models that can represent a cell's shape and dynamics in great detail. We also extensively review the ways in which cells within a tissue choose their direction, the statistics of cell motion, and some simple examples of how cell-cell signaling can interact with collective cell motility. This review also covers in more detail selected recent works on collective cell motion of small numbers of cells on micropatterns, in wound healing, and the chemotaxis of clusters of cells.
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84
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Ferguson EA, Matthiopoulos J, Insall RH, Husmeier D. Statistical inference of the mechanisms driving collective cell movement. J R Stat Soc Ser C Appl Stat 2016. [DOI: 10.1111/rssc.12203] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023]
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85
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Mackenzie JA, Nolan M, Insall RH. Local modulation of chemoattractant concentrations by single cells: dissection using a bulk-surface computational model. Interface Focus 2016; 6:20160036. [PMID: 27708760 PMCID: PMC4992739 DOI: 10.1098/rsfs.2016.0036] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022] Open
Abstract
Chemoattractant gradients are usually considered in terms of sources and sinks that are independent of the chemotactic cell. However, recent interest has focused on 'self-generated' gradients, in which cell populations create their own local gradients as they move. Here, we consider the interplay between chemoattractants and single cells. To achieve this, we extend a recently developed computational model to incorporate breakdown of extracellular attractants by membrane-bound enzymes. Model equations are parametrized, using the published estimates from Dictyostelium cells chemotaxing towards cyclic AMP. We find that individual cells can substantially modulate their local attractant field under physiologically appropriate conditions of attractant and enzymes. This means the attractant concentration perceived by receptors can be a small fraction of the ambient concentration. This allows efficient chemotaxis in chemoattractant concentrations that would be saturating without local breakdown. Similar interactions in which cells locally mould a stimulus could function in many types of directed cell motility, including haptotaxis, durotaxis and even electrotaxis.
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Affiliation(s)
- J. A. Mackenzie
- Department of Mathematics and Statistics, Universityof Strathclyde, Glasgow G1 1XH, UK
| | - M. Nolan
- Department of Mathematics and Statistics, Universityof Strathclyde, Glasgow G1 1XH, UK
| | - R. H. Insall
- Beatson Institute for Cancer Research, Switchback Road, Bearsden G61 1BD, UK
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86
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Ferguson EA, Matthiopoulos J, Insall RH, Husmeier D. Inference of the drivers of collective movement in two cell types: Dictyostelium and melanoma. J R Soc Interface 2016; 13:20160695. [PMID: 27798280 PMCID: PMC5095226 DOI: 10.1098/rsif.2016.0695] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2016] [Accepted: 10/05/2016] [Indexed: 12/30/2022] Open
Abstract
Collective cell movement is a key component of many important biological processes, including wound healing, the immune response and the spread of cancers. To understand and influence these movements, we need to be able to identify and quantify the contribution of their different underlying mechanisms. Here, we define a set of six candidate models-formulated as advection-diffusion-reaction partial differential equations-that incorporate a range of cell movement drivers. We fitted these models to movement assay data from two different cell types: Dictyostelium discoideum and human melanoma. Model comparison using widely applicable information criterion suggested that movement in both of our study systems was driven primarily by a self-generated gradient in the concentration of a depletable chemical in the cells' environment. For melanoma, there was also evidence that overcrowding influenced movement. These applications of model inference to determine the most likely drivers of cell movement indicate that such statistical techniques have potential to support targeted experimental work in increasing our understanding of collective cell movement in a range of systems.
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Affiliation(s)
- Elaine A Ferguson
- Institute of Biodiversity, Animal Health and Comparative Medicine, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow, UK
| | - Jason Matthiopoulos
- Institute of Biodiversity, Animal Health and Comparative Medicine, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow, UK
| | | | - Dirk Husmeier
- School of Mathematics and Statistics, College of Science and Engineering, University of Glasgow, Glasgow, UK
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87
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Tweedy L, Susanto O, Insall RH. Self-generated chemotactic gradients-cells steering themselves. Curr Opin Cell Biol 2016; 42:46-51. [PMID: 27105308 DOI: 10.1016/j.ceb.2016.04.003] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2016] [Accepted: 04/04/2016] [Indexed: 01/26/2023]
Abstract
Chemotaxis is a fundamentally important part of biology, but we know very little about how gradients of chemoattractant are formed. One answer is self-generated gradients, in which the moving cells break down the attractant to provide their own gradient as they migrate. Here we discuss where self-generated gradients are known, how they can be recognized, and where they are likely to be found in the future.
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Affiliation(s)
- Luke Tweedy
- Cancer Research UK Beatson Institute, Switchback Road, Bearsden G61 1BD, UK
| | - Olivia Susanto
- Cancer Research UK Beatson Institute, Switchback Road, Bearsden G61 1BD, UK
| | - Robert H Insall
- Cancer Research UK Beatson Institute, Switchback Road, Bearsden G61 1BD, UK.
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88
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Onset of nonlinearity in a stochastic model for auto-chemotactic advancing epithelia. Sci Rep 2016; 6:33849. [PMID: 27669998 PMCID: PMC5037363 DOI: 10.1038/srep33849] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2016] [Accepted: 09/01/2016] [Indexed: 12/28/2022] Open
Abstract
We investigate the role of auto-chemotaxis in the growth and motility of an epithelium advancing on a solid substrate. In this process, cells create their own chemoattractant allowing communications among neighbours, thus leading to a signaling pathway. As known, chemotaxis provokes the onset of cellular density gradients and spatial inhomogeneities mostly at the front, a phenomenon able to predict some features revealed in in vitro experiments. A continuous model is proposed where the coupling between the cellular proliferation, the friction on the substrate and chemotaxis is investigated. According to our results, the friction and proliferation stabilize the front whereas auto-chemotaxis is a factor of destabilization. This antagonist role induces a fingering pattern with a selected wavenumber k0. However, in the planar front case, the translational invariance of the experimental set-up gives also a mode at k = 0 and the coupling between these two modes in the nonlinear regime is responsible for the onset of a Hopf-bifurcation. The time-dependent oscillations of patterns observed experimentally can be predicted simply in this continuous non-linear approach. Finally the effects of noise are also investigated below the instability threshold.
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89
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Abstract
Cell migration in the “correct” direction is pivotal for many biological processes. Although most work is devoted to its molecular mechanisms, the cell’s preference for one direction over others, thus overcoming intrinsic random motility, epitomizes a profound principle that underlies all complex systems: the choice of one axis, in structure or motion, from a uniform or symmetric set of options. Explaining directional motility by an external chemo-attractant gradient does not solve but only shifts the problem of causation: whence the gradient? A new study in PLOS Biology shows cell migration in a self-generated gradient, offering an opportunity to take a broader look at the old dualism of extrinsic instruction versus intrinsic symmetry-breaking in cell biology. Directional cell motility is enabled by chemoattractant gradient and symmetry-breaking. This Primer argues that the recent observation of cells generating a gradient in a uniformly distributed nutrient reveals the multilayered nature of symmetry-breaking in cell locomotion.
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Affiliation(s)
- Sui Huang
- Institute for Systems Biology, Seattle, Washington
- * E-mail:
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