1
|
Purice MD, Lago‐Baldaia I, Fernandes VM, Singhvi A. Molecular profiling of invertebrate glia. Glia 2025; 73:632-656. [PMID: 39415317 PMCID: PMC11784859 DOI: 10.1002/glia.24623] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2024] [Revised: 09/06/2024] [Accepted: 09/18/2024] [Indexed: 10/18/2024]
Abstract
Caenorhabditis elegans and Drosophila melanogaster are powerful experimental models for uncovering fundamental tenets of nervous system organization and function. Findings over the last two decades show that molecular and cellular features are broadly conserved between invertebrates and vertebrates, indicating that insights derived from invertebrate models can broadly inform our understanding of glial operating principles across diverse species. In recent years, these model systems have led to exciting discoveries in glial biology and mechanisms of glia-neuron interactions. Here, we summarize studies that have applied current state-of-the-art "-omics" techniques to C. elegans and D. melanogaster glia. Coupled with the remarkable acceleration in the pace of mechanistic studies of glia biology in recent years, these indicate that invertebrate glia also exhibit striking molecular complexity, specificity, and heterogeneity. We provide an overview of these studies and discuss their implications as well as emerging questions where C. elegans and D. melanogaster are well-poised to fill critical knowledge gaps in our understanding of glial biology.
Collapse
Affiliation(s)
- Maria D. Purice
- Division of Basic SciencesFred Hutchinson Cancer CenterSeattleWashingtonUSA
- Department of Biological StructureSchool of Medicine, University of WashingtonSeattleWashingtonUSA
| | - Inês Lago‐Baldaia
- Department of Cell and Developmental BiologyUniversity College LondonLondonUK
| | | | - Aakanksha Singhvi
- Division of Basic SciencesFred Hutchinson Cancer CenterSeattleWashingtonUSA
- Department of Biological StructureSchool of Medicine, University of WashingtonSeattleWashingtonUSA
| |
Collapse
|
2
|
Karkali K, Martín-Blanco E. The evolutionary and mechanical principles shaping the Drosophila embryonic ventral nerve cord. Cells Dev 2024; 180:203973. [PMID: 39490740 DOI: 10.1016/j.cdev.2024.203973] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2024] [Revised: 09/19/2024] [Accepted: 10/23/2024] [Indexed: 11/05/2024]
Abstract
The establishment of communication circuits requires bringing sources and targets into contact, either directly or indirectly. The Central Nervous System (CNS)'s ability to interpret the environment and generate precise responses depends on the functional efficiency of its neural network, which in turn relies on the 3D spatial organization of its constituents, mainly neurons and glia. Throughout evolution, sensory integration and motor response coordination became linked with the merging of the brain and nerve cord (NC) in the urbilaterian CNS. In most arthropods, the NC follows a specific topological plan and consists of a fixed number of neuromeres (thoracic and abdominal ganglia with commissural interconnections and a single terminal ganglion). The number, spacing, and fusion of neuromeres are species-specific and can change during embryogenesis or post-embryonic life. During Drosophila embryogenesis, the NC condenses along the Anterior-Posterior (AP) axis in a stereotypical manner, bringing neuromeres closer together. This process has revealed several key parameters, including its morphogenetic mechanics, the roles of various cellular, molecular, and structural components, and the functional purpose of its balanced design. The embryonic NC serves as a valuable model for investigating the ancient mechanisms underlying the structural organization, sensory integration, and motor coordination of the CNS. While many aspects of ganglionic fusion remain unknown, ongoing research promises to provide a more comprehensive understanding of the mechanical and evolutionary principles that govern it.
Collapse
Affiliation(s)
- Katerina Karkali
- Instituto de Biología Molecular de Barcelona (CSIC), Parc Cientific de Barcelona, Baldiri Reixac 10-12, 08028 Barcelona, Spain.
| | - Enrique Martín-Blanco
- Instituto de Biología Molecular de Barcelona (CSIC), Parc Cientific de Barcelona, Baldiri Reixac 10-12, 08028 Barcelona, Spain
| |
Collapse
|
3
|
Brooks EC, Zeidler MP, Ong ACM, Evans IR. Macrophage subpopulation identity in Drosophila is modulated by apoptotic cell clearance and related signalling pathways. Front Immunol 2024; 14:1310117. [PMID: 38283366 PMCID: PMC10811221 DOI: 10.3389/fimmu.2023.1310117] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2023] [Accepted: 12/13/2023] [Indexed: 01/30/2024] Open
Abstract
In Drosophila blood, plasmatocytes of the haemocyte lineage represent the functional equivalent of vertebrate macrophages and have become an established in vivo model with which to study macrophage function and behaviour. However, the use of plasmatocytes as a macrophage model has been limited by a historical perspective that plasmatocytes represent a homogenous population of cells, in contrast to the high levels of heterogeneity of vertebrate macrophages. Recently, a number of groups have reported transcriptomic approaches which suggest the existence of plasmatocyte heterogeneity, while we identified enhancer elements that identify subpopulations of plasmatocytes which exhibit potentially pro-inflammatory behaviours, suggesting conservation of plasmatocyte heterogeneity in Drosophila. These plasmatocyte subpopulations exhibit enhanced responses to wounds and decreased rates of efferocytosis when compared to the overall plasmatocyte population. Interestingly, increasing the phagocytic requirement placed upon plasmatocytes is sufficient to decrease the size of these plasmatocyte subpopulations in the embryo. However, the mechanistic basis for this response was unclear. Here, we examine how plasmatocyte subpopulations are modulated by apoptotic cell clearance (efferocytosis) demands and associated signalling pathways. We show that loss of the phosphatidylserine receptor Simu prevents an increased phagocytic burden from modulating specific subpopulation cells, while blocking other apoptotic cell receptors revealed no such rescue. This suggests that Simu-dependent efferocytosis is specifically involved in determining fate of particular subpopulations. Supportive of our original finding, mutations in amo (the Drosophila homolog of PKD2), a calcium-permeable channel which operates downstream of Simu, phenocopy simu mutants. Furthermore, we show that Amo is involved in the acidification of the apoptotic cell-containing phagosomes, suggesting that this reduction in pH may be associated with macrophage reprogramming. Additionally, our results also identify Ecdysone receptor signalling, a pathway related to control of cell death during developmental transitions, as a controller of plasmatocyte subpopulation identity. Overall, these results identify fundamental pathways involved in the specification of plasmatocyte subpopulations and so further validate Drosophila plasmatocytes as a heterogeneous population of macrophage-like cells within this important developmental and immune model.
Collapse
Affiliation(s)
- Elliot C. Brooks
- School of Medicine and Population Health and the Bateson Centre, University of Sheffield, Sheffield, United Kingdom
| | - Martin P. Zeidler
- School of Biosciences and the Bateson Centre, University of Sheffield, Sheffield, United Kingdom
| | - Albert C. M. Ong
- School of Medicine and Population Health and the Bateson Centre, University of Sheffield, Sheffield, United Kingdom
| | - Iwan R. Evans
- School of Medicine and Population Health and the Bateson Centre, University of Sheffield, Sheffield, United Kingdom
| |
Collapse
|
4
|
Fernandes VM, Auld V, Klämbt C. Glia as Functional Barriers and Signaling Intermediaries. Cold Spring Harb Perspect Biol 2024; 16:a041423. [PMID: 38167424 PMCID: PMC10759988 DOI: 10.1101/cshperspect.a041423] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2024]
Abstract
Glia play a crucial role in providing metabolic support to neurons across different species. To do so, glial cells isolate distinct neuronal compartments from systemic signals and selectively transport specific metabolites and ions to support neuronal development and facilitate neuronal function. Because of their function as barriers, glial cells occupy privileged positions within the nervous system and have also evolved to serve as signaling intermediaries in various contexts. The fruit fly, Drosophila melanogaster, has significantly contributed to our understanding of glial barrier development and function. In this review, we will explore the formation of the glial sheath, blood-brain barrier, and nerve barrier, as well as the significance of glia-extracellular matrix interactions in barrier formation. Additionally, we will delve into the role of glia as signaling intermediaries in regulating nervous system development, function, and response to injury.
Collapse
Affiliation(s)
- Vilaiwan M Fernandes
- Department of Cell and Developmental Biology, University College London, London UC1E 6DE, United Kingdom
| | - Vanessa Auld
- Department of Zoology, University of British Columbia, Vancouver, British Columbia V6T 1Z4, Canada
| | - Christian Klämbt
- Institute for Neuro- and Behavioral Biology, University of Münster, Münster 48149, Germany
| |
Collapse
|
5
|
Heron R, Amato C, Wood W, Davidson AJ. Understanding the diversity and dynamics of in vivo efferocytosis: Insights from the fly embryo. Immunol Rev 2023; 319:27-44. [PMID: 37589239 PMCID: PMC10952863 DOI: 10.1111/imr.13266] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2023] [Accepted: 07/18/2023] [Indexed: 08/18/2023]
Abstract
The clearance of dead and dying cells, termed efferocytosis, is a rapid and efficient process and one that is critical for organismal health. The extraordinary speed and efficiency with which dead cells are detected and engulfed by immune cells within tissues presents a challenge to researchers who wish to unravel this fascinating process, since these fleeting moments of uptake are almost impossible to catch in vivo. In recent years, the fruit fly (Drosophila melanogaster) embryo has emerged as a powerful model to circumvent this problem. With its abundance of dying cells, specialist phagocytes and relative ease of live imaging, the humble fly embryo provides a unique opportunity to catch and study the moment of cell engulfment in real-time within a living animal. In this review, we explore the recent advances that have come from studies in the fly, and how live imaging and genetics have revealed a previously unappreciated level of diversity in the efferocytic program. A variety of efferocytic strategies across the phagocytic cell population ensure efficient and rapid clearance of corpses wherever death is encountered within the varied and complex setting of a multicellular living organism.
Collapse
Affiliation(s)
- Rosalind Heron
- Institute for Regeneration and RepairUniversity of EdinburghEdinburghUK
| | - Clelia Amato
- Institute for Regeneration and RepairUniversity of EdinburghEdinburghUK
| | - Will Wood
- Institute for Regeneration and RepairUniversity of EdinburghEdinburghUK
| | - Andrew J. Davidson
- Institute for Regeneration and RepairUniversity of EdinburghEdinburghUK
- School of Cancer SciencesWolfson Wohl Cancer Research Centre, University of GlasgowGlasgowUK
| |
Collapse
|
6
|
Lago-Baldaia I, Cooper M, Seroka A, Trivedi C, Powell GT, Wilson SW, Ackerman SD, Fernandes VM. A Drosophila glial cell atlas reveals a mismatch between transcriptional and morphological diversity. PLoS Biol 2023; 21:e3002328. [PMID: 37862379 PMCID: PMC10619882 DOI: 10.1371/journal.pbio.3002328] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2023] [Revised: 11/01/2023] [Accepted: 09/08/2023] [Indexed: 10/22/2023] Open
Abstract
Morphology is a defining feature of neuronal identity. Like neurons, glia display diverse morphologies, both across and within glial classes, but are also known to be morphologically plastic. Here, we explored the relationship between glial morphology and transcriptional signature using the Drosophila central nervous system (CNS), where glia are categorised into 5 main classes (outer and inner surface glia, cortex glia, ensheathing glia, and astrocytes), which show within-class morphological diversity. We analysed and validated single-cell RNA sequencing data of Drosophila glia in 2 well-characterised tissues from distinct developmental stages, containing distinct circuit types: the embryonic ventral nerve cord (VNC) (motor) and the adult optic lobes (sensory). Our analysis identified a new morphologically and transcriptionally distinct surface glial population in the VNC. However, many glial morphological categories could not be distinguished transcriptionally, and indeed, embryonic and adult astrocytes were transcriptionally analogous despite differences in developmental stage and circuit type. While we did detect extensive within-class transcriptomic diversity for optic lobe glia, this could be explained entirely by glial residence in the most superficial neuropil (lamina) and an associated enrichment for immune-related gene expression. In summary, we generated a single-cell transcriptomic atlas of glia in Drosophila, and our extensive in vivo validation revealed that glia exhibit more diversity at the morphological level than was detectable at the transcriptional level. This atlas will serve as a resource for the community to probe glial diversity and function.
Collapse
Affiliation(s)
- Inês Lago-Baldaia
- Department of Cell and Developmental Biology, University College London, London, United Kingdom
| | - Maia Cooper
- Department of Cell and Developmental Biology, University College London, London, United Kingdom
| | - Austin Seroka
- Institute of Neuroscience, Howard Hughes Medical Institute, University of Oregon, Eugene, Oregon, United States of America
| | - Chintan Trivedi
- Department of Cell and Developmental Biology, University College London, London, United Kingdom
| | - Gareth T. Powell
- Department of Cell and Developmental Biology, University College London, London, United Kingdom
| | - Stephen W. Wilson
- Department of Cell and Developmental Biology, University College London, London, United Kingdom
| | - Sarah D. Ackerman
- Department of Pathology and Immunology, Brain Immunology and Glia Center, Washington University School of Medicine, Saint Louis, Missouri, United States of America
- Department of Developmental Biology, Washington University School of Medicine, Saint Louis, Missouri, United States of America
| | - Vilaiwan M. Fernandes
- Department of Cell and Developmental Biology, University College London, London, United Kingdom
| |
Collapse
|
7
|
Zechini L, Amato C, Scopelliti A, Wood W. Piezo acts as a molecular brake on wound closure to ensure effective inflammation and maintenance of epithelial integrity. Curr Biol 2022; 32:3584-3592.e4. [PMID: 35835122 PMCID: PMC9616804 DOI: 10.1016/j.cub.2022.06.041] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2021] [Revised: 04/12/2022] [Accepted: 06/14/2022] [Indexed: 12/08/2022]
Abstract
Wound healing entails a fine balance between re-epithelialization and inflammation1,2 so that the risk of infection is minimized, tissue architecture is restored without scarring, and the epithelium regains its ability to withstand mechanical forces. How the two events are orchestrated in vivo remains poorly understood, largely due to the experimental challenges of simultaneously addressing mechanical and molecular aspects of the damage response. Here, exploiting Drosophila's genetic tractability and live imaging potential, we uncover a dual role for Piezo-a mechanosensitive channel involved in calcium influx3-during re-epithelialization and inflammation following injury in vivo. We show that loss of Piezo leads to faster wound closure due to increased wound edge intercalation and exacerbated myosin cable heterogeneity. Moreover, we show that loss of Piezo leads to impaired inflammation due to lower epidermal calcium levels and, subsequently, insufficient damage-induced ROS production. Despite initially appearing beneficial, loss of Piezo is severely detrimental to the long-term effectiveness of repair. In fact, wounds inflicted on Piezo knockout embryos become a permanent point of weakness within the epithelium, leading to impaired barrier function and reduced ability of wounded embryos to survive. In summary, our study uncovers a role for Piezo in regulating epithelial cell dynamics and immune cell responsiveness during damage repair in vivo. We propose a model whereby Piezo acts as molecular brake during wound healing, slowing down closure to ensure activation of sustained inflammation and re-establishment of a fully functional epithelial barrier.
Collapse
Affiliation(s)
- Luigi Zechini
- Centre for Inflammation Research, Queens Medical Research Institute, University of Edinburgh, 47 Little France Crescent, Edinburgh EH16 4TJ, UK
| | - Clelia Amato
- Centre for Inflammation Research, Queens Medical Research Institute, University of Edinburgh, 47 Little France Crescent, Edinburgh EH16 4TJ, UK
| | - Alessandro Scopelliti
- Centre for Inflammation Research, Queens Medical Research Institute, University of Edinburgh, 47 Little France Crescent, Edinburgh EH16 4TJ, UK.
| | - Will Wood
- Centre for Inflammation Research, Queens Medical Research Institute, University of Edinburgh, 47 Little France Crescent, Edinburgh EH16 4TJ, UK.
| |
Collapse
|
8
|
Bakopoulos D, Whisstock JC, Warr CG, Johnson TK. Macrophage self‐renewal is regulated by transient expression of
PDGF‐ and VEGF‐related factor 2. FEBS J 2022; 289:3735-3751. [DOI: 10.1111/febs.16364] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2020] [Revised: 11/24/2021] [Accepted: 01/19/2022] [Indexed: 12/23/2022]
Affiliation(s)
- Daniel Bakopoulos
- School of Biological Sciences Monash University Clayton Vic. Australia
| | - James C. Whisstock
- Australian Research Council Centre of Excellence in Advanced Molecular Imaging, Monash University Clayton Vic. Australia
- Department of Biochemistry and Molecular Biology Monash University Clayton Vic. Australia
| | - Coral G. Warr
- School of Biological Sciences Monash University Clayton Vic. Australia
- School of Molecular Sciences La Trobe University Bundoora Vic. Australia
| | - Travis K. Johnson
- School of Biological Sciences Monash University Clayton Vic. Australia
- Australian Research Council Centre of Excellence in Advanced Molecular Imaging, Monash University Clayton Vic. Australia
| |
Collapse
|
9
|
Nguyen PK, Cheng LY. Non-autonomous regulation of neurogenesis by extrinsic cues: a Drosophila perspective. OXFORD OPEN NEUROSCIENCE 2022; 1:kvac004. [PMID: 38596708 PMCID: PMC10913833 DOI: 10.1093/oons/kvac004] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 01/14/2022] [Revised: 03/20/2022] [Accepted: 03/23/2022] [Indexed: 04/11/2024]
Abstract
The formation of a functional circuitry in the central nervous system (CNS) requires the correct number and subtypes of neural cells. In the developing brain, neural stem cells (NSCs) self-renew while giving rise to progenitors that in turn generate differentiated progeny. As such, the size and the diversity of cells that make up the functional CNS depend on the proliferative properties of NSCs. In the fruit fly Drosophila, where the process of neurogenesis has been extensively investigated, extrinsic factors such as the microenvironment of NSCs, nutrients, oxygen levels and systemic signals have been identified as regulators of NSC proliferation. Here, we review decades of work that explores how extrinsic signals non-autonomously regulate key NSC characteristics such as quiescence, proliferation and termination in the fly.
Collapse
Affiliation(s)
- Phuong-Khanh Nguyen
- Peter MacCallum Cancer Centre, Melbourne, Victoria 3000, Australia
- Department of Anatomy and Physiology, The University of Melbourne, Victoria 3010, Australia
| | - Louise Y Cheng
- Peter MacCallum Cancer Centre, Melbourne, Victoria 3000, Australia
- Sir Peter MacCallum Department of Oncology, The University of Melbourne, Victoria 3010, Australia
- Department of Anatomy and Physiology, The University of Melbourne, Victoria 3010, Australia
| |
Collapse
|
10
|
Condensation of the Drosophila nerve cord is oscillatory and depends on coordinated mechanical interactions. Dev Cell 2022; 57:867-882.e5. [PMID: 35413236 DOI: 10.1016/j.devcel.2022.03.007] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2021] [Revised: 01/19/2022] [Accepted: 03/14/2022] [Indexed: 11/21/2022]
Abstract
During development, organs reach precise shapes and sizes. Organ morphology is not always obtained through growth; a classic counterexample is the condensation of the nervous system during Drosophila embryogenesis. The mechanics underlying such condensation remain poorly understood. Here, we characterize the condensation of the embryonic ventral nerve cord (VNC) at both subcellular and tissue scales. This analysis reveals that condensation is not a unidirectional continuous process but instead occurs through oscillatory contractions. The VNC mechanical properties spatially and temporally vary, and forces along its longitudinal axis are spatially heterogeneous. We demonstrate that the process of VNC condensation is dependent on the coordinated mechanical activities of neurons and glia. These outcomes are consistent with a viscoelastic model of condensation, which incorporates time delays and effective frictional interactions. In summary, we have defined the progressive mechanics driving VNC condensation, providing insights into how a highly viscous tissue can autonomously change shape and size.
Collapse
|
11
|
Davidson AJ, Wood W. Macrophages Use Distinct Actin Regulators to Switch Engulfment Strategies and Ensure Phagocytic Plasticity In Vivo. Cell Rep 2021; 31:107692. [PMID: 32460022 PMCID: PMC7262594 DOI: 10.1016/j.celrep.2020.107692] [Citation(s) in RCA: 25] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2019] [Revised: 04/16/2020] [Accepted: 05/05/2020] [Indexed: 01/02/2023] Open
Abstract
Macrophages must not only be responsive to an array of different stimuli, such as infection and cellular damage, but also perform phagocytosis within the diverse and complex tissue environments found in vivo. This requires a high degree of morphological and therefore cytoskeletal plasticity. Here, we use the exceptional genetics and in vivo imaging of Drosophila embryos to study macrophage phagocytic versatility during apoptotic corpse clearance. We find that macrophage phagocytosis is highly robust, arising from their possession of two distinct modes of engulfment that utilize exclusive suites of actin-regulatory proteins. “Lamellipodial phagocytosis” is Arp2/3-complex-dependent and allows cells to migrate toward and envelop apoptotic corpses. Alternatively, Diaphanous and Ena drive filopodial phagocytosis to reach out and draw in debris. Macrophages switch to “filopodial phagocytosis” to overcome spatial constraint, providing the robust plasticity necessary to ensure that whatever obstacle they encounter in vivo, they fulfil their critical clearance function. Macrophages use two distinct modes of engulfment: lamellipodial and filopodial phagocytosis Arp2/3-complex-dependent lamellipodial phagocytosis involves envelopment via a lamellipod Filopodial phagocytosis involves phagocytic filopods extended by Dia and/or Ena Macrophages switch to filopodial phagocytosis to overcome spatial constraint in vivo
Collapse
Affiliation(s)
- Andrew J Davidson
- Centre for Inflammation Research, University of Edinburgh, Queens Medical Research Institute, 47 Little France Crescent, Edinburgh EH16 4TJ, UK
| | - Will Wood
- Centre for Inflammation Research, University of Edinburgh, Queens Medical Research Institute, 47 Little France Crescent, Edinburgh EH16 4TJ, UK.
| |
Collapse
|
12
|
Coates JA, Brooks E, Brittle AL, Armitage EL, Zeidler MP, Evans IR. Identification of functionally distinct macrophage subpopulations in Drosophila. eLife 2021; 10:e58686. [PMID: 33885361 PMCID: PMC8062135 DOI: 10.7554/elife.58686] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2020] [Accepted: 03/30/2021] [Indexed: 12/24/2022] Open
Abstract
Vertebrate macrophages are a highly heterogeneous cell population, but while Drosophila blood is dominated by a macrophage-like lineage (plasmatocytes), until very recently these cells were considered to represent a homogeneous population. Here, we present our identification of enhancer elements labelling plasmatocyte subpopulations, which vary in abundance across development. These subpopulations exhibit functional differences compared to the overall population, including more potent injury responses and differential localisation and dynamics in pupae and adults. Our enhancer analysis identified candidate genes regulating plasmatocyte behaviour: pan-plasmatocyte expression of one such gene (Calnexin14D) improves wound responses, causing the overall population to resemble more closely the subpopulation marked by the Calnexin14D-associated enhancer. Finally, we show that exposure to increased levels of apoptotic cell death modulates subpopulation cell numbers. Taken together this demonstrates macrophage heterogeneity in Drosophila, identifies mechanisms involved in subpopulation specification and function and facilitates the use of Drosophila to study macrophage heterogeneity in vivo.
Collapse
Affiliation(s)
- Jonathon Alexis Coates
- Department of Biomedical Science and the Bateson Centre, University of SheffieldSheffieldUnited Kingdom
| | - Elliot Brooks
- Department of Infection, Immunity and Cardiovascular Disease and the Bateson Centre, University of SheffieldSheffieldUnited Kingdom
| | - Amy Louise Brittle
- Department of Infection, Immunity and Cardiovascular Disease and the Bateson Centre, University of SheffieldSheffieldUnited Kingdom
| | - Emma Louise Armitage
- Department of Infection, Immunity and Cardiovascular Disease and the Bateson Centre, University of SheffieldSheffieldUnited Kingdom
| | - Martin Peter Zeidler
- Department of Biomedical Science and the Bateson Centre, University of SheffieldSheffieldUnited Kingdom
| | - Iwan Robert Evans
- Department of Infection, Immunity and Cardiovascular Disease and the Bateson Centre, University of SheffieldSheffieldUnited Kingdom
| |
Collapse
|
13
|
Tardy OR, Armitage EL, Prince LR, Evans IR. The Epidermal Growth Factor Ligand Spitz Modulates Macrophage Efferocytosis, Wound Responses and Migration Dynamics During Drosophila Embryogenesis. Front Cell Dev Biol 2021; 9:636024. [PMID: 33898424 PMCID: PMC8060507 DOI: 10.3389/fcell.2021.636024] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2020] [Accepted: 03/19/2021] [Indexed: 12/31/2022] Open
Abstract
How multifunctional cells such as macrophages interpret the different cues within their environment and undertake an appropriate response is a key question in developmental biology. Understanding how cues are prioritized is critical to answering this - both the clearance of apoptotic cells (efferocytosis) and the migration toward damaged tissue is dependent on macrophages being able to interpret and prioritize multiple chemoattractants, polarize, and then undertake an appropriate migratory response. Here, we investigate the role of Spitz, the cardinal Drosophila epidermal growth factor (EGF) ligand, in regulation of macrophage behavior in the developing fly embryo, using activated variants with differential diffusion properties. Our results show that misexpression of activated Spitz can impact macrophage polarity and lead to clustering of cells in a variant-specific manner, when expressed either in macrophages or the developing fly heart. Spitz can also alter macrophage distribution and perturb apoptotic cell clearance undertaken by these phagocytic cells without affecting the overall levels of apoptosis within the embryo. Expression of active Spitz, but not a membrane-bound variant, can also increase macrophage migration speeds and impair their inflammatory responses to injury. The fact that the presence of Spitz specifically undermines the recruitment of more distal cells to wound sites suggests that Spitz desensitizes macrophages to wounds or is able to compete for their attention where wound signals are weaker. Taken together these results suggest this molecule regulates macrophage migration and their ability to dispose of apoptotic cells. This work identifies a novel regulator of Drosophila macrophage function and provides insights into signal prioritization and integration in vivo. Given the importance of apoptotic cell clearance and inflammation in human disease, this work may help us to understand the role EGF ligands play in immune cell recruitment during development and at sites of disease pathology.
Collapse
Affiliation(s)
- Olivier R. Tardy
- Department of Infection, Immunity and Cardiovascular Disease, The Bateson Centre, The University of Sheffield, Sheffield, United Kingdom
- The Bateson Centre, The University of Sheffield, Sheffield, United Kingdom
| | - Emma L. Armitage
- Department of Infection, Immunity and Cardiovascular Disease, The Bateson Centre, The University of Sheffield, Sheffield, United Kingdom
- The Bateson Centre, The University of Sheffield, Sheffield, United Kingdom
| | - Lynne R. Prince
- Department of Infection, Immunity and Cardiovascular Disease, The Bateson Centre, The University of Sheffield, Sheffield, United Kingdom
| | - Iwan R. Evans
- Department of Infection, Immunity and Cardiovascular Disease, The Bateson Centre, The University of Sheffield, Sheffield, United Kingdom
- The Bateson Centre, The University of Sheffield, Sheffield, United Kingdom
| |
Collapse
|
14
|
Mase A, Augsburger J, Brückner K. Macrophages and Their Organ Locations Shape Each Other in Development and Homeostasis - A Drosophila Perspective. Front Cell Dev Biol 2021; 9:630272. [PMID: 33777939 PMCID: PMC7991785 DOI: 10.3389/fcell.2021.630272] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2020] [Accepted: 01/25/2021] [Indexed: 12/15/2022] Open
Abstract
Across the animal kingdom, macrophages are known for their functions in innate immunity, but they also play key roles in development and homeostasis. Recent insights from single cell profiling and other approaches in the invertebrate model organism Drosophila melanogaster reveal substantial diversity among Drosophila macrophages (plasmatocytes). Together with vertebrate studies that show genuine expression signatures of macrophages based on their organ microenvironments, it is expected that Drosophila macrophage functional diversity is shaped by their anatomical locations and systemic conditions. In vivo evidence for diverse macrophage functions has already been well established by Drosophila genetics: Drosophila macrophages play key roles in various aspects of development and organogenesis, including embryogenesis and development of the nervous, digestive, and reproductive systems. Macrophages further maintain homeostasis in various organ systems and promote regeneration following organ damage and injury. The interdependence and interplay of tissues and their local macrophage populations in Drosophila have implications for understanding principles of organ development and homeostasis in a wide range of species.
Collapse
Affiliation(s)
- Anjeli Mase
- Department of Cell and Tissue Biology, University of California, San Francisco, San Francisco, CA, United States
| | - Jordan Augsburger
- Department of Cell and Tissue Biology, University of California, San Francisco, San Francisco, CA, United States
| | - Katja Brückner
- Department of Cell and Tissue Biology, University of California, San Francisco, San Francisco, CA, United States
- Eli and Edythe Broad Center of Regeneration Medicine and Stem Cell Research, University of California, San Francisco, San Francisco, CA, United States
- Cardiovascular Research Institute, University of California, San Francisco, San Francisco, CA, United States
| |
Collapse
|
15
|
Csordás G, Gábor E, Honti V. There and back again: The mechanisms of differentiation and transdifferentiation in Drosophila blood cells. Dev Biol 2020; 469:135-143. [PMID: 33131706 DOI: 10.1016/j.ydbio.2020.10.006] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2020] [Revised: 10/06/2020] [Accepted: 10/15/2020] [Indexed: 12/21/2022]
Abstract
Transdifferentiation is a conversion of an already differentiated cell type into another cell type without the involvement of stem cells. This transition is well described in the case of vertebrate immune cells, as well as in Drosophila melanogaster, which therefore serves as a suitable model to study the process in detail. In the Drosophila larva, the latest single-cell sequencing methods enabled the clusterization of the phagocytic blood cells, the plasmatocytes, which are capable of transdifferentiation into encapsulating cells, the lamellocytes. Here we summarize the available data of the past years on the plasmatocyte-lamellocyte transition, and make an attempt to harmonize them with transcriptome-based blood cell clustering to better understand the underlying mechanisms of transdifferentiation in Drosophila, and in general.
Collapse
Affiliation(s)
- Gábor Csordás
- Institute for Genetics and Cologne Excellence Cluster on Cellular Stress Responses in Aging-Associated Diseases (CECAD), University of Cologne, 50931, Cologne, Germany.
| | - Erika Gábor
- Institute of Genetics, Biological Research Centre, Szeged, H-6701, P.O.Box 521, Hungary.
| | - Viktor Honti
- Institute of Genetics, Biological Research Centre, Szeged, H-6701, P.O.Box 521, Hungary.
| |
Collapse
|
16
|
Armitage EL, Roddie HG, Evans IR. Overexposure to apoptosis via disrupted glial specification perturbs Drosophila macrophage function and reveals roles of the CNS during injury. Cell Death Dis 2020; 11:627. [PMID: 32796812 PMCID: PMC7428013 DOI: 10.1038/s41419-020-02875-2] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2020] [Revised: 07/31/2020] [Accepted: 08/03/2020] [Indexed: 12/15/2022]
Abstract
Apoptotic cell clearance by phagocytes is a fundamental process during development, homeostasis and the resolution of inflammation. However, the demands placed on phagocytic cells such as macrophages by this process, and the limitations these interactions impose on subsequent cellular behaviours are not yet clear. Here, we seek to understand how apoptotic cells affect macrophage function in the context of a genetically tractable Drosophila model in which macrophages encounter excessive amounts of apoptotic cells. Loss of the glial-specific transcription factor Repo prevents glia from contributing to apoptotic cell clearance in the developing embryo. We show that this leads to the challenge of macrophages with large numbers of apoptotic cells in vivo. As a consequence, macrophages become highly vacuolated with cleared apoptotic cells, and their developmental dispersal and migration is perturbed. We also show that the requirement to deal with excess apoptosis caused by a loss of repo function leads to impaired inflammatory responses to injury. However, in contrast to migratory phenotypes, defects in wound responses cannot be rescued by preventing apoptosis from occurring within a repo mutant background. In investigating the underlying cause of these impaired inflammatory responses, we demonstrate that wound-induced calcium waves propagate into surrounding tissues, including neurons and glia of the ventral nerve cord, which exhibit striking calcium waves on wounding, revealing a previously unanticipated contribution of these cells during responses to injury. Taken together, these results demonstrate important insights into macrophage biology and how repo mutants can be used to study macrophage-apoptotic cell interactions in the fly embryo. Furthermore, this work shows how these multipurpose cells can be 'overtasked' to the detriment of their other functions, alongside providing new insights into which cells govern macrophage responses to injury in vivo.
Collapse
Affiliation(s)
- Emma Louise Armitage
- Department of Infection, Immunity and Cardiovascular Disease and The Bateson Centre, University of Sheffield, Sheffield, UK
| | - Hannah Grace Roddie
- Department of Infection, Immunity and Cardiovascular Disease and The Bateson Centre, University of Sheffield, Sheffield, UK
| | - Iwan Robert Evans
- Department of Infection, Immunity and Cardiovascular Disease and The Bateson Centre, University of Sheffield, Sheffield, UK.
| |
Collapse
|
17
|
Crews ST. Drosophila Embryonic CNS Development: Neurogenesis, Gliogenesis, Cell Fate, and Differentiation. Genetics 2019; 213:1111-1144. [PMID: 31796551 PMCID: PMC6893389 DOI: 10.1534/genetics.119.300974] [Citation(s) in RCA: 25] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2019] [Accepted: 09/26/2019] [Indexed: 01/04/2023] Open
Abstract
The Drosophila embryonic central nervous system (CNS) is a complex organ consisting of ∼15,000 neurons and glia that is generated in ∼1 day of development. For the past 40 years, Drosophila developmental neuroscientists have described each step of CNS development in precise molecular genetic detail. This has led to an understanding of how an intricate nervous system emerges from a single cell. These studies have also provided important, new concepts in developmental biology, and provided an essential model for understanding similar processes in other organisms. In this article, the key genes that guide Drosophila CNS development and how they function is reviewed. Features of CNS development covered in this review are neurogenesis, gliogenesis, cell fate specification, and differentiation.
Collapse
Affiliation(s)
- Stephen T Crews
- Department of Biochemistry and Biophysics, Integrative Program for Biological and Genome Sciences, School of Medicine, The University of North Carolina at Chapel Hill, North Carolina 27599
| |
Collapse
|
18
|
Wu W, Kuo T, Kao C, Girardot C, Hung S, Liu T, Furlong EEM, Liu Y. Expanding the mesodermal transcriptional network by genome‐wide identification of Zinc finger homeodomain 1 (Zfh1) targets. FEBS Lett 2019; 593:1698-1710. [DOI: 10.1002/1873-3468.13443] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2018] [Revised: 05/09/2019] [Accepted: 05/13/2019] [Indexed: 11/11/2022]
Affiliation(s)
- Wei‐Hang Wu
- Department of Life Sciences College of Bioscience and Biotechnology National Cheng Kung University Tainan Taiwan
| | - Tai‐Hong Kuo
- Department of Life Sciences College of Bioscience and Biotechnology National Cheng Kung University Tainan Taiwan
| | - Chia‐Wei Kao
- Department of Life Sciences College of Bioscience and Biotechnology National Cheng Kung University Tainan Taiwan
| | - Charles Girardot
- Genome Biology Unit, European Molecular Biology Laboratory (EMBL) Heidelberg Germany
| | - Sheng‐Jou Hung
- Department of Biotechnology and Bioindustry Sciences College of Bioscience and Biotechnology National Cheng Kung University Tainan Taiwan
| | - Tsunglin Liu
- Department of Biotechnology and Bioindustry Sciences College of Bioscience and Biotechnology National Cheng Kung University Tainan Taiwan
| | - Eileen E. M. Furlong
- Genome Biology Unit, European Molecular Biology Laboratory (EMBL) Heidelberg Germany
| | - Ya‐Hsin Liu
- Department of Life Sciences College of Bioscience and Biotechnology National Cheng Kung University Tainan Taiwan
| |
Collapse
|
19
|
Simu-dependent clearance of dying cells regulates macrophage function and inflammation resolution. PLoS Biol 2019; 17:e2006741. [PMID: 31086359 PMCID: PMC6516643 DOI: 10.1371/journal.pbio.2006741] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2018] [Accepted: 04/10/2019] [Indexed: 12/30/2022] Open
Abstract
Macrophages encounter and clear apoptotic cells during normal development and homeostasis, including at numerous sites of pathology. Clearance of apoptotic cells has been intensively studied, but the effects of macrophage-apoptotic cell interactions on macrophage behaviour are poorly understood. Using Drosophila embryos, we have exploited the ease of manipulating cell death and apoptotic cell clearance in this model to identify that the loss of the apoptotic cell clearance receptor Six-microns-under (Simu) leads to perturbation of macrophage migration and inflammatory responses via pathological levels of apoptotic cells. Removal of apoptosis ameliorates these phenotypes, while acute induction of apoptosis phenocopies these defects and reveals that phagocytosis of apoptotic cells is not necessary for their anti-inflammatory action. Furthermore, Simu is necessary for clearance of necrotic debris and retention of macrophages at wounds. Thus, Simu is a general detector of damaged self and represents a novel molecular player regulating macrophages during resolution of inflammation.
Collapse
|
20
|
Valoskova K, Biebl J, Roblek M, Emtenani S, Gyoergy A, Misova M, Ratheesh A, Reis-Rodrigues P, Shkarina K, Larsen ISB, Vakhrushev SY, Clausen H, Siekhaus DE. A conserved major facilitator superfamily member orchestrates a subset of O-glycosylation to aid macrophage tissue invasion. eLife 2019; 8:e41801. [PMID: 30910009 PMCID: PMC6435326 DOI: 10.7554/elife.41801] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2018] [Accepted: 02/11/2019] [Indexed: 12/29/2022] Open
Abstract
Aberrant display of the truncated core1 O-glycan T-antigen is a common feature of human cancer cells that correlates with metastasis. Here we show that T-antigen in Drosophila melanogaster macrophages is involved in their developmentally programmed tissue invasion. Higher macrophage T-antigen levels require an atypical major facilitator superfamily (MFS) member that we named Minerva which enables macrophage dissemination and invasion. We characterize for the first time the T and Tn glycoform O-glycoproteome of the Drosophila melanogaster embryo, and determine that Minerva increases the presence of T-antigen on proteins in pathways previously linked to cancer, most strongly on the sulfhydryl oxidase Qsox1 which we show is required for macrophage tissue entry. Minerva's vertebrate ortholog, MFSD1, rescues the minerva mutant's migration and T-antigen glycosylation defects. We thus identify a key conserved regulator that orchestrates O-glycosylation on a protein subset to activate a program governing migration steps important for both development and cancer metastasis.
Collapse
Affiliation(s)
| | - Julia Biebl
- Institute of Science and Technology AustriaKlosterneuburgAustria
| | - Marko Roblek
- Institute of Science and Technology AustriaKlosterneuburgAustria
| | - Shamsi Emtenani
- Institute of Science and Technology AustriaKlosterneuburgAustria
| | - Attila Gyoergy
- Institute of Science and Technology AustriaKlosterneuburgAustria
| | - Michaela Misova
- Institute of Science and Technology AustriaKlosterneuburgAustria
| | - Aparna Ratheesh
- Institute of Science and Technology AustriaKlosterneuburgAustria
- Centre for Mechanochemical Cell Biology and Division of Biomedical Sciences, Warwick Medical SchoolUniversity of WarwickCoventryUnited Kingdom
| | | | | | - Ida Signe Bohse Larsen
- Copenhagen Center for Glycomics, Department of Cellular and Molecular Medicine, Faculty of Health SciencesUniversity of CopenhagenCopenhagenDenmark
| | - Sergey Y Vakhrushev
- Copenhagen Center for Glycomics, Department of Cellular and Molecular Medicine, Faculty of Health SciencesUniversity of CopenhagenCopenhagenDenmark
| | - Henrik Clausen
- Copenhagen Center for Glycomics, Department of Cellular and Molecular Medicine, Faculty of Health SciencesUniversity of CopenhagenCopenhagenDenmark
| | - Daria E Siekhaus
- Institute of Science and Technology AustriaKlosterneuburgAustria
| |
Collapse
|
21
|
Sánchez-Sánchez BJ, Urbano JM, Comber K, Dragu A, Wood W, Stramer B, Martín-Bermudo MD. Drosophila Embryonic Hemocytes Produce Laminins to Strengthen Migratory Response. Cell Rep 2018; 21:1461-1470. [PMID: 29117553 PMCID: PMC5695906 DOI: 10.1016/j.celrep.2017.10.047] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2017] [Revised: 09/05/2017] [Accepted: 10/11/2017] [Indexed: 12/28/2022] Open
Abstract
The most prominent developmental function attributed to the extracellular matrix (ECM) is cell migration. While cells in culture can produce ECM to migrate, the role of ECM in regulating developmental cell migration is classically viewed as an exogenous matrix presented to the moving cells. In contrast to this view, we show here that Drosophila embryonic hemocytes deposit their own laminins in streak-like structures to migrate efficiently throughout the embryo. With the help of transplantation experiments, live microscopy, and image quantification, we demonstrate that autocrine-produced laminin regulates hemocyte migration by controlling lamellipodia dynamics, stability, and persistence. Proper laminin deposition is regulated by the RabGTPase Rab8, which is highly expressed and required in hemocytes for lamellipodia dynamics and migration. Our results thus support a model in which, during embryogenesis, the Rab8-regulated autocrine deposition of laminin reinforces directional and effective migration by stabilizing cellular protrusions and strengthening otherwise transient adhesion states. Drosophila embryonic hemocytes use autocrine-produced laminins for their migration Autocrine laminins regulate lamellipodia dynamics, stability, and persistence Rab8 regulates laminin deposition and lamellipodia dynamics in migrating hemocytes Laminins deposit in tracks around hemocytes and in a fibrillar mesh over the VNC
Collapse
Affiliation(s)
- Besaiz J Sánchez-Sánchez
- CABD (CSIC-Universidad Pablo de Olavide-JA), Sevilla 41013, Spain; Randall Centre for Cell and Molecular Biophysics, King's College London, London SE5 9AP, UK
| | - José M Urbano
- Department of Physiology, Development and Neuroscience, University of Cambridge, Cambridge CB2 3DY, UK
| | - Kate Comber
- Department of Cellular and Molecular Medicine, Biomedical Sciences, University of Bristol, Bristol BS8 1TD, UK
| | - Anca Dragu
- Randall Centre for Cell and Molecular Biophysics, King's College London, London SE5 9AP, UK
| | - Will Wood
- Department of Cellular and Molecular Medicine, Biomedical Sciences, University of Bristol, Bristol BS8 1TD, UK
| | - Brian Stramer
- Randall Centre for Cell and Molecular Biophysics, King's College London, London SE5 9AP, UK
| | | |
Collapse
|
22
|
Connecting the nervous and the immune systems in evolution. Commun Biol 2018; 1:64. [PMID: 30271946 PMCID: PMC6123671 DOI: 10.1038/s42003-018-0070-2] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2018] [Accepted: 05/14/2018] [Indexed: 01/28/2023] Open
Abstract
Despite their great importance for biomedical research, the intricate network of relationships between macro- and microglia, in terms of development, function and evolution, remains poorly understood. Drawing inspiration from the recent meeting “Of Glia and Microglia”, held at the University of Strasbourg in December 2017, we here discuss the outstanding questions in the seemingly disparate fields of glial development, physiology and evolution, and also provide suggestions for how the field should move forward. Volker Hartenstein and Angela Giangrande discuss recent advances and future directions in glial biology and evolution in the context of a recent scientific conference. Their Comment illustrates the importance of interdisciplinary approaches to answering outstanding questions in biology.
Collapse
|
23
|
Ghosh S, Mandal S, Mandal L. Detecting proliferation of adult hemocytes in Drosophila by BrdU incorporation. Wellcome Open Res 2018. [DOI: 10.12688/wellcomeopenres.14560.1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Drosophila and mammalian hematopoiesis share several similarities that ranges from phases to the battery of transcription factors and signaling molecules that execute this process. These resounding similarities along with the rich genetic tools available in fruitfly makes it a popular invertebrate model to study blood cell development both during normal and aberrant conditions. The larval system is the most extensively studied to date. Several studies have shown that these hemocytes just like mammalian counterpart proliferate and get routinely regenerated upon infection. However, employing the same protocol it was concluded that blood cell proliferation although abundant in larval stages is absent in adult fruitfly. The current protocol describes the strategies that can be employed to document the hemocyte proliferation in adulthood. The fact that a subset of blood cells tucked away in the hematopoietic hub are not locked in senescence, rather they still harbour the proliferative capacity to tide over challenges was successfully demonstrated by this method. Although we have adopted bacterial infection as a bait to evoke this proliferative capacity of the hemocytes, we envision that it can also efficiently characterize the proliferative responses of hemocytes in tumorigenic conditions as well as scenarios of environmental and metabolic stresses during adulthood.
Collapse
|
24
|
Ghosh S, Mandal S, Mandal L. Detecting proliferation of adult hemocytes in Drosophila by BrdU incorporation. Wellcome Open Res 2018; 3:47. [PMID: 29946570 PMCID: PMC5989151 DOI: 10.12688/wellcomeopenres.14560.2] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 04/17/2018] [Indexed: 01/25/2023] Open
Abstract
Drosophila and mammalian hematopoiesis share several similarities that ranges from phases to the battery of transcription factors and signaling molecules that execute this process. These resounding similarities along with the rich genetic tools available in fruitfly makes it a popular invertebrate model to study blood cell development both during normal and aberrant conditions. The larval system is the most extensively studied to date. Several studies have shown that these hemocytes just like mammalian counterpart proliferate and get routinely regenerated upon infection. However, employing the same protocol it was concluded that blood cell proliferation although abundant in larval stages is absent in adult fruitfly. The current protocol describes the strategies that can be employed to document the hemocyte proliferation in adulthood. The fact that a subset of blood cells tucked away in the hematopoietic hub are not locked in senescence, rather they still harbour the proliferative capacity to tide over challenges was successfully demonstrated by this method. Although we have adopted bacterial infection as a bait to evoke this proliferative capacity of the hemocytes, we envision that it can also efficiently characterize the proliferative responses of hemocytes in tumorigenic conditions as well as scenarios of environmental and metabolic stresses during adulthood.
Collapse
Affiliation(s)
- Saikat Ghosh
- Developmental Genetics Laboratory, Department of Biological Sciences, Indian Institute of Science Education and Research-Mohali, Manauli, Punjab, 140306, India
| | - Sudip Mandal
- Molecular Cell and Developmental Biology Laboratory, Department of Biological Sciences, Indian Institute of Science Education and Research-Mohali, Manauli, Punjab, 140306, India
| | - Lolitika Mandal
- Developmental Genetics Laboratory, Department of Biological Sciences, Indian Institute of Science Education and Research-Mohali, Manauli, Punjab, 140306, India
| |
Collapse
|
25
|
Wood W, Martin P. Macrophage Functions in Tissue Patterning and Disease: New Insights from the Fly. Dev Cell 2017; 40:221-233. [PMID: 28171746 PMCID: PMC5300050 DOI: 10.1016/j.devcel.2017.01.001] [Citation(s) in RCA: 63] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2016] [Revised: 12/02/2016] [Accepted: 01/04/2017] [Indexed: 12/19/2022]
Abstract
Macrophages are multifunctional innate immune cells that seed all tissues within the body and play disparate roles throughout development and in adult tissues, both in health and disease. Their complex developmental origins and many of their functions are being deciphered in mammalian tissues, but opportunities for live imaging and the genetic tractability of Drosophila are offering complementary insights into how these fascinating cells integrate a multitude of guidance cues to fulfill their many tasks and migrate to distant sites to either direct developmental patterning or raise an inflammatory response.
Collapse
Affiliation(s)
- Will Wood
- Department of Cellular and Molecular Medicine, Biomedical Sciences, University of Bristol, Bristol BS8 1TD, UK.
| | - Paul Martin
- Departments of Biochemistry and Physiology, Pharmacology and Neuroscience, Biomedical Sciences, University of Bristol, Bristol BS8 1TD, UK; School of Medicine, Cardiff University, Cardiff CF14 4XN, UK; Lee Kong Chiang School of Medicine, Nanyang Technological University, Singapore 636921, Singapore.
| |
Collapse
|
26
|
Bae YK, Macabenta F, Curtis HL, Stathopoulos A. Comparative analysis of gene expression profiles for several migrating cell types identifies cell migration regulators. Mech Dev 2017; 148:40-55. [PMID: 28428068 DOI: 10.1016/j.mod.2017.04.004] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2017] [Revised: 04/13/2017] [Accepted: 04/13/2017] [Indexed: 01/11/2023]
Abstract
Cell migration is an instrumental process that ensures cells are properly positioned to support the specification of distinct tissue types during development. To provide insight, we used fluorescence activated cell sorting (FACS) to isolate two migrating cell types from the Drosophila embryo: caudal visceral mesoderm (CVM) cells, precursors of longitudinal muscles of the gut, and hemocytes (HCs), the Drosophila equivalent of blood cells. ~350 genes were identified from each of the sorted samples using RNA-seq, and in situ hybridization was used to confirm expression within each cell type or, alternatively, within other interacting, co-sorted cell types. To start, the two gene expression profiling datasets were compared to identify cell migration regulators that are potentially generally-acting. 73 genes were present in both CVM cell and HC gene expression profiles, including the transcription factor zinc finger homeodomain-1 (zfh1). Comparisons with gene expression profiles of Drosophila border cells that migrate during oogenesis had a more limited overlap, with only the genes neyo (neo) and singed (sn) found to be expressed in border cells as well as CVM cells and HCs, respectively. Neo encodes a protein with Zona pellucida domain linked to cell polarity, while sn encodes an actin binding protein. Tissue specific RNAi expression coupled with live in vivo imaging was used to confirm cell-autonomous roles for zfh1 and neo in supporting CVM cell migration, whereas previous studies had demonstrated a role for Sn in supporting HC migration. In addition, comparisons were made to migrating cells from vertebrates. Seven genes were found expressed by chick neural crest cells, CVM cells, and HCs including extracellular matrix (ECM) proteins and proteases. In summary, we show that genes shared in common between CVM cells, HCs, and other migrating cell types can help identify regulators of cell migration. Our analyses show that neo in addition to zfh1 and sn studied previously impact cell migration. This study also suggests that modification of the extracellular milieu may be a fundamental requirement for cells that undergo cell streaming migratory behaviors.
Collapse
Affiliation(s)
- Young-Kyung Bae
- Division of Biology and Biological Engineering, California Institute of Technology, 1200 East California Blvd., Pasadena, CA 91125, United States; Korea Research Institute of Standards and Science, Center for Bio-Analysis, Yuseung-gu, Gajung-ro 267, Daejeon, Republic of Korea
| | - Frank Macabenta
- Division of Biology and Biological Engineering, California Institute of Technology, 1200 East California Blvd., Pasadena, CA 91125, United States
| | - Heather Leigh Curtis
- Division of Biology and Biological Engineering, California Institute of Technology, 1200 East California Blvd., Pasadena, CA 91125, United States
| | - Angelike Stathopoulos
- Division of Biology and Biological Engineering, California Institute of Technology, 1200 East California Blvd., Pasadena, CA 91125, United States.
| |
Collapse
|
27
|
Schwabe T, Li X, Gaul U. Dynamic analysis of the mesenchymal-epithelial transition of blood-brain barrier forming glia in Drosophila. Biol Open 2017; 6:232-243. [PMID: 28108476 PMCID: PMC5312092 DOI: 10.1242/bio.020669] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
During development, many epithelia are formed by a mesenchymal-epithelial transition (MET). Here, we examine the major stages and underlying mechanisms of MET during blood-brain barrier formation in Drosophila. We show that contact with the basal lamina is essential for the growth of the barrier-forming subperineurial glia (SPG). Septate junctions (SJs), which provide insulation of the paracellular space, are not required for MET, but are necessary for the establishment of polarized SPG membrane compartments. In vivo time-lapse imaging reveals that the Moody GPCR signaling pathway regulates SPG cell growth and shape, with different levels of signaling causing distinct phenotypes. Timely, well-coordinated SPG growth is essential for the uniform insertion of SJs and thus the insulating function of the barrier. To our knowledge, this is the first dynamic in vivo analysis of all stages in the formation of a secondary epithelium, and of the key role trimeric G protein signaling plays in this important morphogenetic process. Summary: This study examines the major steps and underlying mechanisms of mesenchymal-epithelial transition of the blood-brain-barrier forming glia in Drosophila, including the role of basal lamina, septate junctions and of trimeric G protein signaling.
Collapse
Affiliation(s)
- Tina Schwabe
- Department of Biochemistry, Gene Center, Center of Integrated Protein Science (CIPSM), University of Munich, Feodor-Lynen-Str. 25, Munich 81377, Germany
| | - Xiaoling Li
- Department of Biochemistry, Gene Center, Center of Integrated Protein Science (CIPSM), University of Munich, Feodor-Lynen-Str. 25, Munich 81377, Germany.,Rockefeller University, 1230 York Ave, New York, 10065-6399 NY, USA
| | - Ulrike Gaul
- Department of Biochemistry, Gene Center, Center of Integrated Protein Science (CIPSM), University of Munich, Feodor-Lynen-Str. 25, Munich 81377, Germany
| |
Collapse
|
28
|
Weavers H, Evans IR, Martin P, Wood W. Corpse Engulfment Generates a Molecular Memory that Primes the Macrophage Inflammatory Response. Cell 2016; 165:1658-1671. [PMID: 27212238 PMCID: PMC4912690 DOI: 10.1016/j.cell.2016.04.049] [Citation(s) in RCA: 150] [Impact Index Per Article: 16.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2015] [Revised: 02/05/2016] [Accepted: 04/13/2016] [Indexed: 01/15/2023]
Abstract
Macrophages are multifunctional cells that perform diverse roles in health and disease. Emerging evidence has suggested that these innate immune cells might also be capable of developing immunological memory, a trait previously associated with the adaptive system alone. While recent studies have focused on the dramatic macrophage reprogramming that follows infection and protects against secondary microbial attack, can macrophages also develop memory in response to other cues? Here, we show that apoptotic corpse engulfment by Drosophila macrophages is an essential primer for their inflammatory response to tissue damage and infection in vivo. Priming is triggered via calcium-induced JNK signaling, which leads to upregulation of the damage receptor Draper, thus providing a molecular memory that allows the cell to rapidly respond to subsequent injury or infection. This remarkable plasticity and capacity for memory places macrophages as key therapeutic targets for treatment of inflammatory disorders. Phagocytosis of apoptotic cells primes macrophages for future inflammatory response Naive macrophages are insensitive to tissue damage and bacterial infection Corpse uptake triggers macrophage calcium bursts that potentiate priming Calcium-induced JNK primes macrophages by upregulating the damage receptor Draper
Collapse
Affiliation(s)
- Helen Weavers
- Department of Biochemistry, Biomedical Sciences, University of Bristol, Bristol BS8 1TD, UK; Department of Cellular and Molecular Medicine, Biomedical Sciences, University of Bristol, Bristol BS8 1TD, UK
| | - Iwan R Evans
- Department of Infection, Immunity and Cardiovascular Disease and the Bateson Centre, University of Sheffield, Sheffield S10 2TN, UK
| | - Paul Martin
- Department of Biochemistry, Biomedical Sciences, University of Bristol, Bristol BS8 1TD, UK; Department of Physiology, Pharmacology and Neuroscience, Biomedical Sciences, University of Bristol, Bristol BS8 1TD, UK; School of Medicine, Cardiff University, Cardiff CF14 4XN, UK; Lee Kong Chiang School of Medicine, Nanyang Technologicial University, Singapore 636921, Singapore.
| | - Will Wood
- Department of Cellular and Molecular Medicine, Biomedical Sciences, University of Bristol, Bristol BS8 1TD, UK.
| |
Collapse
|
29
|
Parsons B, Foley E. Cellular immune defenses of Drosophila melanogaster. DEVELOPMENTAL AND COMPARATIVE IMMUNOLOGY 2016; 58:95-101. [PMID: 26748247 DOI: 10.1016/j.dci.2015.12.019] [Citation(s) in RCA: 43] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/14/2015] [Revised: 12/23/2015] [Accepted: 12/23/2015] [Indexed: 06/05/2023]
Abstract
Drosophila melanogaster is a widely used model for the characterization of blood cell development and function, with an array of protocols for the manipulation and visualization of fixed or live cells in vitro or in vivo. Researchers have deployed these techniques to reveal Drosophila hemocytes as a remarkably versatile cell type that engulfs apoptotic corpses; neutralizes invading parasites; seals epithelial wounds; and deposits extracellular matrix proteins. In this review, we will discuss the key features of Drosophila hemocyte development and function, and identify similarities with vertebrate counterparts.
Collapse
Affiliation(s)
- Brendon Parsons
- 1B3.14, 8440-112 Street, Walter Mackenzie Health Sciences Centre, University of Alberta, Edmonton, AB, T6G 2J2, Canada
| | - Edan Foley
- University of Alberta, Department of Medical Microbiology and Immunology, Canada.
| |
Collapse
|
30
|
Vlisidou I, Wood W. Drosophila blood cells and their role in immune responses. FEBS J 2015; 282:1368-82. [PMID: 25688716 DOI: 10.1111/febs.13235] [Citation(s) in RCA: 104] [Impact Index Per Article: 10.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2014] [Revised: 02/02/2015] [Accepted: 02/12/2015] [Indexed: 12/17/2022]
Abstract
Drosophila melanogaster has been extensively used to study the humoral arm of innate immunity because of the developmental and functional parallels with mammalian innate immunity. However, the fly cellular response to infection is far less understood. Investigative work on Drosophila haemocytes, the immunosurveillance cells of the insect, has revealed that they fulfil roles similar to mammalian monocytes and macrophages. They respond to wound signals and orchestrate the coagulation response. In addition, they phagocytose and encapsulate invading pathogens, and clear up apoptotic bodies controlling inflammation. This review briefly describes the Drosophila haematopoietic system and discusses what is currently known about the contribution of haemocytes to the immune response upon infection and wounding, during all stages of development.
Collapse
Affiliation(s)
- Isabella Vlisidou
- School of Cellular and Molecular Medicine, University of Bristol, UK
| | | |
Collapse
|
31
|
Benton JL, Kery R, Li J, Noonin C, Söderhäll I, Beltz BS. Cells from the immune system generate adult-born neurons in crayfish. Dev Cell 2014; 30:322-33. [PMID: 25117683 DOI: 10.1016/j.devcel.2014.06.016] [Citation(s) in RCA: 49] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2012] [Revised: 04/08/2014] [Accepted: 06/19/2014] [Indexed: 10/24/2022]
Abstract
Neurogenesis is an ongoing process in the brains of adult decapod crustaceans. However, the first-generation precursors that produce adult-born neurons, which reside in a neurogenic niche, are not self-renewing in crayfish and must be replenished. The source of these neuronal precursors is unknown. Here, we report that adult-born neurons in crayfish can be derived from hemocytes. Following adoptive transfer of 5-ethynyl-2'-deoxyuridine (EdU)-labeled hemocytes, labeled cells populate the neurogenic niche containing the first-generation neuronal precursors. Seven weeks after adoptive transfer, EdU-labeled cells are located in brain clusters 9 and 10 (where adult-born neurons differentiate) and express appropriate neurotransmitters. Moreover, the number of cells composing the neurogenic niche in crayfish is tightly correlated with total hemocyte counts (THCs) and can be manipulated by raising or lowering THC. These studies identify hemocytes as a source of adult-born neurons in crayfish and demonstrate that the immune system is a key contributor to adult neurogenesis.
Collapse
Affiliation(s)
- Jeanne L Benton
- Neuroscience Program, Wellesley College, Wellesley, MA 02481, USA
| | - Rachel Kery
- Neuroscience Program, Wellesley College, Wellesley, MA 02481, USA
| | - Jingjing Li
- Neuroscience Program, Wellesley College, Wellesley, MA 02481, USA
| | - Chadanat Noonin
- Department of Comparative Physiology, Uppsala University, SE-752 36 Uppsala, Sweden
| | - Irene Söderhäll
- Department of Comparative Physiology, Uppsala University, SE-752 36 Uppsala, Sweden.
| | - Barbara S Beltz
- Neuroscience Program, Wellesley College, Wellesley, MA 02481, USA.
| |
Collapse
|
32
|
Evans CJ, Liu T, Banerjee U. Drosophila hematopoiesis: Markers and methods for molecular genetic analysis. Methods 2014; 68:242-51. [PMID: 24613936 PMCID: PMC4051208 DOI: 10.1016/j.ymeth.2014.02.038] [Citation(s) in RCA: 76] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2014] [Revised: 02/26/2014] [Accepted: 02/28/2014] [Indexed: 01/09/2023] Open
Abstract
Analyses of the Drosophila hematopoietic system are becoming more and more prevalent as developmental and functional parallels with vertebrate blood cells become more evident. Investigative work on the fly blood system has, out of necessity, led to the identification of new molecular markers for blood cell types and lineages and to the refinement of useful molecular genetic tools and analytical methods. This review briefly describes the Drosophila hematopoietic system at different developmental stages, summarizes the major useful cell markers and tools for each stage, and provides basic protocols for practical analysis of circulating blood cells and of the lymph gland, the larval hematopoietic organ.
Collapse
Affiliation(s)
- Cory J Evans
- Department of Molecular, Cell and Developmental Biology, University of California, Los Angeles, Los Angeles, CA 90095, USA
| | - Ting Liu
- Department of Molecular, Cell and Developmental Biology, University of California, Los Angeles, Los Angeles, CA 90095, USA
| | - Utpal Banerjee
- Department of Molecular, Cell and Developmental Biology, University of California, Los Angeles, Los Angeles, CA 90095, USA; Department of Biological Chemistry, University of California, Los Angeles, Los Angeles, CA 90095, USA; Molecular Biology Institute, University of California, Los Angeles, Los Angeles, CA 90095, USA; Eli and Edythe Broad Center of Regenerative Medicine and Stem Cell Research, University of California, Los Angeles, Los Angeles, CA 90095, USA.
| |
Collapse
|
33
|
Meyer S, Schmidt I, Klämbt C. Glia ECM interactions are required to shape the Drosophila nervous system. Mech Dev 2014; 133:105-16. [PMID: 24859129 DOI: 10.1016/j.mod.2014.05.003] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2013] [Revised: 05/10/2014] [Accepted: 05/14/2014] [Indexed: 10/25/2022]
Abstract
Organs are characterized by a specific shape that is often remodeled during development. The dynamics of organ shape is in particular evident during the formation of the Drosophila nervous system. During embryonic stages the central nervous system compacts, whereas selective growth occurs during larval stages. The nervous system is covered by a layer of surface glial cells that form the blood brain barrier and a thick extracellular matrix called neural lamella. The size of the neural lamella is dynamically adjusted to the growing nervous system and we show here that perineurial glial cells secrete proteases to remodel this matrix. Moreover, an imbalance in proteolytic activity results in an abnormal shape of the nervous system. To identify further components controlling nervous system shape we performed an RNAi based screen and identified the gene nolo, which encodes an ADAMTS-like protein. We generated loss of function alleles and demonstrate a requirement in glial cells. Mutant nolo larvae, however, do not show an abnormal nervous system shape. The only predicted off-target of the nolo(dsRNA) is Oatp30B, which encodes an organic anion transporting protein characterized by an extracellular protease inhibitor domain. Loss of function mutants were generated and double mutant analyses demonstrate a genetic interaction between nolo and Oatp30B which prevented the generation of maternal zygotic mutant larvae.
Collapse
Affiliation(s)
- Silke Meyer
- Institute of Neurobiology, University of Münster, 48149 Münster, Germany
| | - Imke Schmidt
- Institute of Neurobiology, University of Münster, 48149 Münster, Germany
| | - Christian Klämbt
- Institute of Neurobiology, University of Münster, 48149 Münster, Germany.
| |
Collapse
|
34
|
Abstract
Integrin-mediated adhesion used by Drosophila blood cells to migrate in vivo. SCAR/WAVE is required for lamellipodia but also for clearance of apoptotic cells. The formins Fhos and Diaphanous regulate Drosophila macrophage migration and morphology. Calcium waves drive hydrogen peroxide production to regulate inflammatory migrations. The steroid hormone Ecdysone controls the onset of immune competence.
Drosophila melanogaster contains a population of blood cells called hemocytes that represent the functional equivalent of vertebrate macrophages. These cells undergo directed migrations to disperse during development and reach sites of tissue damage or altered self. These chemotactic behaviors are controlled by the expression of PDGF/Vegf-related ligands in developing embryos and local production of hydrogen peroxide at wounds. Recent work reveals that many molecules important in vertebrate cell motility, including integrins, formins, Ena/VASP proteins and the SCAR/WAVE complex, have a conserved function in these innate immune cells. The use of this model organism has elucidated how damage signals are activated by calcium signaling during inflammation and that the steroid hormone ecdysone activates immune competence at key developmental stages.
Collapse
Affiliation(s)
- Iwan Robert Evans
- Department of Infection and Immunity, The Medical School, University of Sheffield, Beech Hill Road, Sheffield S10 2RX, UK; The Bateson Centre, University of Sheffield, Sheffield S10 2TN, UK
| | - Will Wood
- Faculty of Medical and Veterinary Sciences, University of Bristol, University Walk, Bristol BS8 1TD, UK.
| |
Collapse
|
35
|
Honti V, Csordás G, Kurucz É, Márkus R, Andó I. The cell-mediated immunity of Drosophila melanogaster: hemocyte lineages, immune compartments, microanatomy and regulation. DEVELOPMENTAL AND COMPARATIVE IMMUNOLOGY 2014; 42:47-56. [PMID: 23800719 DOI: 10.1016/j.dci.2013.06.005] [Citation(s) in RCA: 140] [Impact Index Per Article: 12.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/19/2013] [Revised: 06/10/2013] [Accepted: 06/11/2013] [Indexed: 06/02/2023]
Abstract
In the animal kingdom, innate immunity is the first line of defense against invading pathogens. The dangers of microbial and parasitic attacks are countered by similar mechanisms, involving the prototypes of the cell-mediated immune responses, the phagocytosis and encapsulation. Work on Drosophila has played an important role in promoting an understanding of the basic mechanisms of phylogenetically conserved modules of innate immunity. The aim of this review is to survey the developments in the identification and functional definition of immune cell types and the immunological compartments of Drosophila melanogaster. We focus on the molecular and developmental aspects of the blood cell types and compartments, as well as the dynamics of blood cell development and the immune response. Further advances in the characterization of the innate immune mechanisms in Drosophila will provide basic clues to the understanding of the importance of the evolutionary conserved mechanisms of innate immune defenses in the animal kingdom.
Collapse
Affiliation(s)
- Viktor Honti
- Institute of Genetics Biological Research Centre of the Hungarian Academy of Sciences, P.O. Box 521, Szeged H-6701, Hungary
| | | | | | | | | |
Collapse
|
36
|
Abstract
Drosophila hemocytes compose the cellular arm of the fly's innate immune system. Plasmatocytes, putative homologues to mammalian macrophages, represent ∼95% of the migratory hemocyte population in circulation and are responsible for the phagocytosis of bacteria and apoptotic tissues that arise during metamorphosis. It is not known as to how hemocytes become activated from a sessile state in response to such infectious and developmental cues, although the hormone ecdysone has been suggested as the signal that shifts hemocyte behaviour from quiescent to migratory at metamorphosis. Here, we corroborate this hypothesis by showing the activation of hemocyte motility by ecdysone. We induce motile behaviour in larval hemocytes by culturing them with 20-hydroxyecdysone ex vivo. Moreover, we also determine that motile cell behaviour requires the ecdysone receptor complex and leads to asymmetrical redistribution of both actin and tubulin cytoskeleton.
Collapse
|
37
|
Parsons B, Foley E. The Drosophila platelet-derived growth factor and vascular endothelial growth factor-receptor related (Pvr) protein ligands Pvf2 and Pvf3 control hemocyte viability and invasive migration. J Biol Chem 2013; 288:20173-83. [PMID: 23737520 DOI: 10.1074/jbc.m113.483818] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Vascular endothelial growth factor (VEGF) and platelet-derived growth factor (PDGF) family members are essential and evolutionary conserved determinants of blood cell development and dispersal. In addition, VEGFs are integral to vascular growth and permeability with detrimental contributions to ischemic diseases and metastatic cancers. The PDGF/VEGF-receptor related (Pvr) protein is implicated in the migration and trophic maintenance of macrophage-like hemocytes in Drosophila melanogaster embryos. pvr mutants have a depleted hemocyte population and a breakdown in hemocyte distribution. Previous studies suggested redundant functions for the Pvr ligands, Pvf2 and Pvf3 in the regulation of hemocyte migration, proliferation, and size. However, the precise roles that Pvf2 and Pvf3 play in hematopoiesis remain unclear due to the lack of available mutants. To determine Pvf2 and Pvf3 functions in vivo, we generated a genomic deletion that simultaneously disrupts Pvf2 and Pvf3. From our studies, we identified contributions of Pvf2 and Pvf3 to the Pvr trophic maintenance of hemocytes. Furthermore, we uncovered a novel role for Pvfs in invasive migrations. We showed that Pvf2 and Pvf3 are not required for the directed migration of hemocytes, but act locally in epithelial cells to coordinate trans-epithelial migration of hemocytes. Our findings redefine Pvf roles in hemocyte migration and highlight novel Pvf roles in hemocyte invasive migration. These new parallels between the Pvr and PDGF/VEGF pathways extend the utility of the Drosophila embryonic system to dissect physiological and pathological roles of PDGF/VEGF-like growth factors.
Collapse
Affiliation(s)
- Brendon Parsons
- Department of Medical Microbiology and Immunology, University of Alberta, Edmonton, Alberta T6G 2S2, Canada
| | | |
Collapse
|
38
|
Comber K, Huelsmann S, Evans I, Sánchez-Sánchez BJ, Chalmers A, Reuter R, Wood W, Martín-Bermudo MD. A dual role for the βPS integrin myospheroid in mediating Drosophila embryonic macrophage migration. J Cell Sci 2013; 126:3475-84. [PMID: 23704353 PMCID: PMC3730248 DOI: 10.1242/jcs.129700] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
Throughout embryonic development, macrophages not only act as the first line of defence against infection but also help to sculpt organs and tissues of the embryo by removing dead cells and secreting extracellular matrix components. Key to their function is the ability of embryonic macrophages to migrate and disperse throughout the embryo. Despite these important developmental functions, little is known about the molecular mechanisms underlying embryonic macrophage migration in vivo. Integrins are key regulators of many of the adult macrophage responses, but their role in embryonic macrophages remains poorly characterized. Here, we have used Drosophila macrophages (haemocytes) as a model system to address the role of integrins during embryonic macrophage dispersal in vivo. We show that the main βPS integrin, myospheroid, affects haemocyte migration in two ways; by shaping the three-dimensional environment in which haemocytes migrate and by regulating the migration of haemocytes themselves. Live imaging revealed a requirement for myospheroid within haemocytes to coordinate the microtubule and actin dynamics, and to enable haemocyte developmental dispersal, contact repulsion and inflammatory migration towards wounds.
Collapse
Affiliation(s)
- Kate Comber
- Department of Biology and Biochemistry, University of Bath, Bath BA2 7AY, UK
| | | | | | | | | | | | | | | |
Collapse
|
39
|
SCAR/WAVE-mediated processing of engulfed apoptotic corpses is essential for effective macrophage migration in Drosophila. Cell Death Differ 2013; 20:709-20. [PMID: 23328632 PMCID: PMC3619236 DOI: 10.1038/cdd.2012.166] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023] Open
Abstract
In vitro studies have shown that SCAR/WAVE activates the Arp2/3 complex to generate actin filaments, which in many cell types are organised into lamellipodia that are thought to have an important role in cell migration. Here we demonstrate that SCAR is utilised by Drosophila macrophages to drive their developmental and inflammatory migrations and that it is regulated via the Hem/Kette/Nap1-containing SCAR/WAVE complex. SCAR is also important in protecting against bacterial pathogens and in wound repair as SCAR mutant embryos succumb more readily to both sterile and infected wounds. However, in addition to driving the formation of lamellipodia in macrophages, SCAR is required cell autonomously for the correct processing of phagocytosed apoptotic corpses by these professional phagocytes. Removal of this phagocytic burden by preventing apoptosis rescues macrophage lamellipodia formation and partially restores motility. Our results show that efficient processing of phagosomes is critical for effective macrophage migration in vivo. These findings have important implications for the resolution of macrophages from chronic wounds and the behaviour of those associated with tumours, because phagocytosis of debris may serve to prolong the presence of these cells at these sites of pathology.
Collapse
|
40
|
Seifert JRK, Lehmann R. Drosophila primordial germ cell migration requires epithelial remodeling of the endoderm. Development 2012; 139:2101-6. [PMID: 22619387 DOI: 10.1242/dev.078949] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
Trans-epithelial migration describes the ability of migrating cells to cross epithelial tissues and occurs during development, infection, inflammation, immune surveillance, wound healing and cancer metastasis. Here we investigate Drosophila primordial germ cells (PGCs), which migrate through the endodermal epithelium. Through live imaging and genetic experimentation we demonstrate that PGCs take advantage of endodermal tissue remodeling to gain access to the gonadal mesoderm and are unable to migrate through intact epithelial tissues. These results are in contrast to the behavior of leukocytes, which actively loosen epithelial junctions to migrate, and raise the possibility that in other contexts in which migrating cells appear to breach tissue barriers, they are actually exploiting existing tissue permeability. Therefore, the use of active invasive programs is not the sole mechanism to infiltrate tissues.
Collapse
Affiliation(s)
- Jessica R K Seifert
- HHMI and Kimmel Center for Biology and Medicine at the Skirball Institute, Department of Cell Biology, New York University School of Medicine, New York, NY 10016, USA
| | | |
Collapse
|
41
|
Parisi F, Vidal M. Epithelial delamination and migration: lessons from Drosophila. Cell Adh Migr 2011; 5:366-72. [PMID: 21836393 DOI: 10.4161/cam.5.4.17524] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
Metastasis is the most deadly phase of cancer progression, during which cells detach from their original niche to invade distant tissues, yet the biological processes underlying the spread of cancer are still poorly understood. The fruit fly Drosophila melanogaster provides important insights in our understanding of how epithelial cells migrate from their original location and find their way into surrounding and distant tissues in the metastatic process. Here we review recent studies on the mechanisms of migration of embryonic haemocytes, the macrophage-like immuno-surveillance cells, during normal development and wound healing. We highlight the interesting finding that hydrogen peroxide (H₂O₂) has been identified as the driving force for haemocyte chemotaxis. We also give a special emphasis to studies suggesting the concept that haemocytes, together with the tumor microenvironment, act as potential inducers of the epithelial de-lamination required for tumor invasion. We propose that cell delamination and migration could be uncoupled from loss of cell polarity via a tumor-related inflammatory response.
Collapse
Affiliation(s)
- Federica Parisi
- Beatson Institute for Cancer Research, Bearsden, Glasgow, UK
| | | |
Collapse
|
42
|
Evans IR, Wood W. Understanding in vivo blood cell migration--Drosophila hemocytes lead the way. Fly (Austin) 2011; 5:110-4. [PMID: 21150318 PMCID: PMC3127059 DOI: 10.4161/fly.5.2.14055] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2010] [Revised: 10/28/2010] [Accepted: 10/29/2010] [Indexed: 11/19/2022] Open
Abstract
Drosophila embryonic hemocytes have emerged as a potent system to analyze the roles of key regulators of the actin and microtubule cytoskeletons live and in an in vivo context (see Table I and references therein). The relative ease with which live imaging can be used to visualize the invasive migrations of these highly motile macrophages and their responses to wound and chemoattractant signals make them a particularly appropriate and genetically tractable cell type to study in relation to pathological conditions such as cancer metastasis and inflammation. ( 1-3) In order to understand how signaling pathways are integrated for a coordinated response, a question with direct relevance to autoimmune dysfunction, we have sought to more fully characterize the inputs these cells receive in vivo over the course of their developmental dispersal. These studies have recently revealed that hemocyte migration is intimately associated with the development of the ventral nerve cord (VNC), a structure used by hemocytes to disperse over the embryo that itself requires this association for its correct morphogenesis. Crucially the VNC must separate from the epidermis to create a channel for hemocyte migration, revealing how constriction of extracellular space can be used to control cell migration in vivo. ( 4).
Collapse
Affiliation(s)
- Iwan Robert Evans
- Department of Biology and Biochemistry, University of Bath, Bath, Somerset, UK
| | | |
Collapse
|
43
|
Tucker PK, Evans IR, Wood W. Ena drives invasive macrophage migration in Drosophila embryos. Dis Model Mech 2010; 4:126-34. [PMID: 21045209 PMCID: PMC3008967 DOI: 10.1242/dmm.005694] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023] Open
Abstract
It is seldom the primary tumour that proves fatal in cancer, with metastasis the fundamental pathological process for disease progression. Upregulation of Mena, a member of the evolutionarily conserved Ena/VASP family of actin cytoskeletal regulators, promotes metastasis and invasive motility of breast cancer cells in vivo. To complement in vitro studies of Ena/VASP function in fibroblasts, we manipulated levels of Ena, the Drosophila homologue of Mena, in migrating embryonic macrophages (haemocytes). Consistent with data from fibroblasts in vitro, Ena localises to regions of actin dynamics within migrating haemocytes, stimulates lamellipodial dynamics and positively regulates the number and length of filopodia. However, whereas Ena overexpression in fibroblasts reduces migration speeds, overexpressing Ena in haemocytes leads to a dramatic increase in migration speeds, more closely resembling the increased motility of breast cancer cells that overexpress Mena. We provide evidence that this key difference is due to spatial constraints imposed on cells within the three-dimensional environment of the embryo; this might explain how Mena can be used to promote aggressive migratory behaviour during cancer progression.
Collapse
Affiliation(s)
- Philippa K Tucker
- Department of Biology and Biochemistry, University of Bath, Bath BA2 7AY, UK
| | | | | |
Collapse
|