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Song W, Jia P, Ren Y, Xue J, Zhou B, Xu X, Shan Y, Deng J, Zhou Q. Engineering white blood cell membrane-camouflaged nanocarriers for inflammation-related therapeutics. Bioact Mater 2023; 23:80-100. [DOI: 10.1016/j.bioactmat.2022.10.026] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2022] [Revised: 10/11/2022] [Accepted: 10/25/2022] [Indexed: 11/11/2022] Open
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2
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Ishikawa-Ankerhold H, Kroll J, van den Heuvel D, Renkawitz J, Müller-Taubenberger A. Centrosome Positioning in Migrating Dictyostelium Cells. Cells 2022; 11:cells11111776. [PMID: 35681473 PMCID: PMC9179490 DOI: 10.3390/cells11111776] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2022] [Revised: 05/23/2022] [Accepted: 05/26/2022] [Indexed: 02/04/2023] Open
Abstract
Directional cell migration and the establishment of polarity play an important role in development, wound healing, and host cell defense. While actin polymerization provides the driving force at the cell front, the microtubule network assumes a regulatory function, in coordinating front protrusion and rear retraction. By using Dictyostelium discoideum cells as a model for amoeboid movement in different 2D and 3D environments, the position of the centrosome relative to the nucleus was analyzed using live-cell microscopy. Our results showed that the centrosome was preferentially located rearward of the nucleus under all conditions tested for directed migration, while the nucleus was oriented toward the expanding front. When cells are hindered from straight movement by obstacles, the centrosome is displaced temporarily from its rearward location to the side of the nucleus, but is reoriented within seconds. This relocalization is supported by the presence of intact microtubules and their contact with the cortex. The data suggest that the centrosome is responsible for coordinating microtubules with respect to the nucleus. In summary, we have analyzed the orientation of the centrosome during different modes of migration in an amoeboid model and present evidence that the basic principles of centrosome positioning and movement are conserved between Dictyostelium and human leukocytes.
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Affiliation(s)
- Hellen Ishikawa-Ankerhold
- Department of Internal Medicine I, University Hospital, Faculty of Medicine, LMU Munich, 81377 Munich, Germany; (H.I.-A.); (D.v.d.H.)
- Walter-Brendel-Centre of Experimental Medicine, University Hospital, Faculty of Medicine, LMU Munich, 81377 Munich, Germany
| | - Janina Kroll
- Biomedical Center Munich (BMC), Department of Cardiovascular Physiology and Pathophysiology, Walter-Brendel-Centre of Experimental Medicine, University Hospital, Faculty of Medicine, LMU Munich, 82152 Planegg-Martinsried, Germany; (J.K.); (J.R.)
| | - Dominic van den Heuvel
- Department of Internal Medicine I, University Hospital, Faculty of Medicine, LMU Munich, 81377 Munich, Germany; (H.I.-A.); (D.v.d.H.)
- Walter-Brendel-Centre of Experimental Medicine, University Hospital, Faculty of Medicine, LMU Munich, 81377 Munich, Germany
| | - Jörg Renkawitz
- Biomedical Center Munich (BMC), Department of Cardiovascular Physiology and Pathophysiology, Walter-Brendel-Centre of Experimental Medicine, University Hospital, Faculty of Medicine, LMU Munich, 82152 Planegg-Martinsried, Germany; (J.K.); (J.R.)
| | - Annette Müller-Taubenberger
- Biomedical Center Munich (BMC), Department of Cell Biology (Anatomy III), Faculty of Medicine, LMU Munich, 82152 Planegg-Martinsried, Germany
- Correspondence: ; Tel.: +49-89-2180-75873
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3
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Wang D, Wang S, Zhou Z, Bai D, Zhang Q, Ai X, Gao W, Zhang L. White Blood Cell Membrane-Coated Nanoparticles: Recent Development and Medical Applications. Adv Healthc Mater 2022; 11:e2101349. [PMID: 34468090 DOI: 10.1002/adhm.202101349] [Citation(s) in RCA: 51] [Impact Index Per Article: 25.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2021] [Revised: 08/19/2021] [Indexed: 12/20/2022]
Abstract
White blood cells (WBCs) are immune cells that play essential roles in critical diseases including cancers, infections, and inflammatory disorders. Their dynamic and diverse functions have inspired the development of WBC membrane-coated nanoparticles (denoted "WBC-NPs"), which are formed by fusing the plasma membranes of WBCs, such as macrophages, neutrophils, T cells, and natural killer cells, onto synthetic nanoparticle cores. Inheriting the entire source cell antigens, WBC-NPs act as source cell decoys and simulate their broad biointerfacing properties with intriguing therapeutic potentials. Herein, the recent development and medical applications of WBC-NPs focusing on four areas, including WBC-NPs as carriers for drug delivery, as countermeasures for biological neutralization, as nanovaccines for immune modulation, and as tools for the isolation of circulating tumor cells and fundamental research is reviewed. Overall, the recent development and studies of WBC-NPs have established the platform as versatile nanotherapeutics and tools with broad medical application potentials.
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Affiliation(s)
- Dan Wang
- Department of NanoEngineering, Chemical Engineering Program, Moores Cancer Center University of California San Diego La Jolla San Diego CA 92093 USA
| | - Shuyan Wang
- Department of NanoEngineering, Chemical Engineering Program, Moores Cancer Center University of California San Diego La Jolla San Diego CA 92093 USA
| | - Zhidong Zhou
- Department of NanoEngineering, Chemical Engineering Program, Moores Cancer Center University of California San Diego La Jolla San Diego CA 92093 USA
| | - Dean Bai
- Department of NanoEngineering, Chemical Engineering Program, Moores Cancer Center University of California San Diego La Jolla San Diego CA 92093 USA
| | - Qiangzhe Zhang
- Department of NanoEngineering, Chemical Engineering Program, Moores Cancer Center University of California San Diego La Jolla San Diego CA 92093 USA
| | - Xiangzhao Ai
- Department of NanoEngineering, Chemical Engineering Program, Moores Cancer Center University of California San Diego La Jolla San Diego CA 92093 USA
| | - Weiwei Gao
- Department of NanoEngineering, Chemical Engineering Program, Moores Cancer Center University of California San Diego La Jolla San Diego CA 92093 USA
| | - Liangfang Zhang
- Department of NanoEngineering, Chemical Engineering Program, Moores Cancer Center University of California San Diego La Jolla San Diego CA 92093 USA
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Brazill D, Knecht DA. Chemotaxis: Under Agarose Assay. Methods Mol Biol 2022; 2364:327-338. [PMID: 34542861 DOI: 10.1007/978-1-0716-1661-1_16] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
Abstract
The unicellular eukaryotic amoeba, Dictyostelium discoideum, represents a superb model for examining the molecular mechanism of chemotaxis. Under vegetative conditions, the amoebae are chemotactically responsive to pterins, such as folic acid. Under starved conditions, they lose their sensitivity to pterins and become chemotactically responsive to cAMP. As an NIH model system, Dictyostelium offers a variety of advantages in studying chemotaxis, including ease of growth, genetic tractability, and the conservation of mammalian signaling pathways. In this chapter, we describe the use of the under-agarose chemotaxis assay to understand the signaling pathways controlling directional sensing and motility in Dictyostelium discoideum. Given the similarities between Dictyostelium and mammalian cells, this allows us to dissect conserved pathways involved in eukaryotic chemotaxis.
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Affiliation(s)
- Derrick Brazill
- Department of Biological Sciences, Hunter College, New York, NY, USA. .,The Graduate Center, City University of New York, New York, NY, USA.
| | - David A Knecht
- Department of Molecular and Cell Biology, University of Connecticut, Storrs, CT, USA.
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5
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Clapis JR, Fan MJ, Kovarik ML. Supported bilayer membranes for reducing cell adhesion in microfluidic devices. ANALYTICAL METHODS : ADVANCING METHODS AND APPLICATIONS 2021; 13:1535-1540. [PMID: 33690748 DOI: 10.1039/d0ay01992e] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
The high surface area-to-volume ratio of microfluidic channels makes them susceptible to fouling and clogging when used for biological analyses, including cell-based assays. We evaluated the role of electrostatic and van der Waals interactions in cell adhesion in PDMS microchannels coated with supported lipid bilayers and identified conditions that resulted in minimal cell adhesion. For low ionic strength buffer, optimum results were obtained for a zwitterionic coating of pure egg phosphatidylcholine; for a rich growth medium, the best results were obtained for zwitterionic bilayers or those with slight negative or moderate positive charge from the incorporation of 5-10 mol% egg phosphatidylglycerol or 30 mol% ethylphosphocholine. In both solutions, the presence of 10 g L-1 glucose in the cell suspension reduced cell adhesion. Under optimum conditions, all cells were consistently removed from the channels, demonstrating the utility of these coatings for whole-cell microfluidic assays. These results provide practical information for immediate application and suggest future research areas on cell-lipid interactions.
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Affiliation(s)
- Julia R Clapis
- Department of Chemistry, Trinity College, 300 Summit St., Hartford, CT 06106, USA.
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Wang Y, Li H, Li F. ELMO2 association with G αi2 regulates pancreatic cancer cell chemotaxis and metastasis. PeerJ 2020; 8:e8910. [PMID: 32292657 PMCID: PMC7144586 DOI: 10.7717/peerj.8910] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2019] [Accepted: 03/15/2020] [Indexed: 01/22/2023] Open
Abstract
Background Pancreatic cancer is a highly lethal disease. Nearly half of the patients have distant metastasis and remain asymptomatic. Emerging evidence suggests that the chemokine, CXCL12, has a role in cancer metastasis. The interaction between CXCL12 and CXCR4 activates heterotrimeric G proteins, which regulates actin polymerization and cancer cell migration. However, the molecular mechanisms underlying pancreatic cancer cell migration are still largely obscure. Here, we addressed the role of ELMO2 in chemotaxis and metastasis of pancreatic cancer cells. Methods Pancreatic cancer cell lines PANC-1 and AsPC-1 and siRNA-mediated knockdown of ELMO2 were used to determine the effects of ELMO2 on cancer cell chemotaxis, invasion, migration. Co-immunoprecipitation assays were carried out to identify interacting partners of ELMO2. Results ELMO2 knockdown inhibited pancreatic cancer cell chemotaxis, migration, invasion, and F-actin polymerization. Co-immunoprecipitation assays revealed that ELMO2 interacted with Gαi2 and that CXCL12 triggered Gα i2-dependent membrane translocation of ELMO2. Thus, ELMO2 is a potential therapeutic target for pancreatic cancer.
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Affiliation(s)
- Yecheng Wang
- Department of General Surgery, Xuanwu Hospital, Capital Medical University, Beijing, China
| | - Hongyan Li
- Department of General Surgery, Xuanwu Hospital, Capital Medical University, Beijing, China
| | - Fei Li
- Department of General Surgery, Xuanwu Hospital, Capital Medical University, Beijing, China
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7
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Abstract
Adaptation refers to the biological phenomenon where living systems change their internal states in response to changes in their environments in order to maintain certain key functions critical for their survival and fitness. Adaptation is one of the most ubiquitous and arguably one of the most fundamental properties of living systems. It occurs throughout all biological scales, from adaptation of populations of species over evolutionary time to adaptation of a single cell to different environmental stresses during its life span. In this article, we review some of the recent progress made in understanding molecular mechanisms of cellular level adaptation. We take the minimalist (or the physicist) approach and study the simplest systems that exhibit generic adaptive behaviors. We focus on understanding the basic biochemical interaction networks in living matter that are responsible for adaptation dynamics. By combining theoretical modeling with quantitative experimentation, we demonstrate universal features in adaptation as well as important differences in different cellular systems, including chemotaxis in bacterium cells (Escherichia coli) and eukaryotic cells (Dictyostelium). Future work in extending the modeling framework to study adaptation in more complex systems such as sensory neurons are discussed.
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Affiliation(s)
- Yuhai Tu
- IBM T. J. Watson Research Center, Yorktown Heights, NY 10598
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Vilaplana J, Alves R, Solsona F, Mateo J, Teixidó I, Pifarré M. MetReS, an Efficient Database for Genomic Applications. J Comput Biol 2017; 25:200-213. [PMID: 29185792 DOI: 10.1089/cmb.2017.0103] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
MetReS (Metabolic Reconstruction Server) is a genomic database that is shared between two software applications that address important biological problems. Biblio-MetReS is a data-mining tool that enables the reconstruction of molecular networks based on automated text-mining analysis of published scientific literature. Homol-MetReS allows functional (re)annotation of proteomes, to properly identify both the individual proteins involved in the processes of interest and their function. The main goal of this work was to identify the areas where the performance of the MetReS database performance could be improved and to test whether this improvement would scale to larger datasets and more complex types of analysis. The study was started with a relational database, MySQL, which is the current database server used by the applications. We also tested the performance of an alternative data-handling framework, Apache Hadoop. Hadoop is currently used for large-scale data processing. We found that this data handling framework is likely to greatly improve the efficiency of the MetReS applications as the dataset and the processing needs increase by several orders of magnitude, as expected to happen in the near future.
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Affiliation(s)
- Jordi Vilaplana
- 1 Department of Computer Science and INSPIRES, University of Lleida , Lleida, Spain
| | - Rui Alves
- 2 Department of Basic Medical Sciences and IRBLleida, University of Lleida , Lleida, Spain
| | - Francesc Solsona
- 1 Department of Computer Science and INSPIRES, University of Lleida , Lleida, Spain
| | - Jordi Mateo
- 1 Department of Computer Science and INSPIRES, University of Lleida , Lleida, Spain
| | - Ivan Teixidó
- 1 Department of Computer Science and INSPIRES, University of Lleida , Lleida, Spain
| | - Marc Pifarré
- 1 Department of Computer Science and INSPIRES, University of Lleida , Lleida, Spain
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9
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Abstract
The unicellular eukaryote Dictyostelium discoideum represents a superb model for examining chemotaxis. Under vegetative conditions, the amoebae are chemotactically responsive to pterins, such as folate. Under starved conditions, they lose their sensitivity to pterins, and become chemotactically responsive to cAMP. As an NIH model system, Dictyostelium offers a variety of advantages in studying chemotaxis, including its conservation of mammalian signaling pathways, its ease of growth, and its genetic tractability. In this chapter, we describe the use of the under agarose chemotaxis assay to identify proteins involved in controlling motility and directional sensing in Dictyostelium discoideum. Given the similarities between Dictyostelium and mammalian cells, this allows us to dissect the conserved pathways involved in eukaryotic chemotaxis.
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10
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Gómez S, López-Estepa M, Fernández FJ, Suárez T, Vega MC. Alternative Eukaryotic Expression Systems for the Production of Proteins and Protein Complexes. ADVANCED TECHNOLOGIES FOR PROTEIN COMPLEX PRODUCTION AND CHARACTERIZATION 2016; 896:167-84. [DOI: 10.1007/978-3-319-27216-0_11] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
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11
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Yan J, Jin T. Signaling network from GPCR to the actin cytoskeleton during chemotaxis. BIOARCHITECTURE 2014; 2:15-18. [PMID: 22754623 PMCID: PMC3383712 DOI: 10.4161/bioa.19740] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
Chemotaxis is crucial for many physiological processes including the recruitment of leukocytes to sites of infection, trafficking of lymphocytes in the human body, and metastasis of cancer cells. A family of small proteins, chemokines, serves as the signals, and a family of G-protein coupled receptors (GPCRs) detects chemokines and direct cell migration. One of the basic questions in chemotaxis of eukaryotes is how a GPCR transduces signals to control the assembly of the actin network that generates directional force for cell migration. Over the past decade, a variety of signaling components have been implicated to transduce the GPCR signaling to the actin cytoskeleton. Studies in a lower eukaryotic organism, Dictyostelium discoideum, have allowed us to discover evolutionary conversed components involved in the GPCR-controlled actin network during chemotaxis. However, complete pathways linking GPCR to the actin network are still far from clear. Here we first summarize the previous studies on these components, and then update with our finding showing a new pathway, consisting of a GPCR, Gβγ, Elmo/Dock, Rac and Arp2/3 and actin. We suggest that this pathway serves as a direct linkage between the GPCR/G-protein, the chemoattractant sensing machinery, and the actin cytoskeleton, the machinery of cell movement during chemotaxis of eukaryotic cells.
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Affiliation(s)
- Jianshe Yan
- Chemotaxis Signal Section; Laboratory of Immunogenetics; National Institute of Allergy and Infectious Diseases; National Institutes of Health; Rockville, MD USA
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12
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Database constraints applied to metabolic pathway reconstruction tools. ScientificWorldJournal 2014; 2014:967294. [PMID: 25202745 PMCID: PMC4151372 DOI: 10.1155/2014/967294] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2014] [Revised: 07/07/2014] [Accepted: 07/08/2014] [Indexed: 12/02/2022] Open
Abstract
Our group developed two biological applications, Biblio-MetReS and Homol-MetReS, accessing the same database of organisms with annotated genes. Biblio-MetReS is a data-mining application that facilitates the reconstruction of molecular networks based on automated text-mining analysis of published scientific literature. Homol-MetReS allows functional (re)annotation of proteomes, to properly identify both the individual proteins involved in the process(es) of interest and their function. It also enables the sets of proteins involved in the process(es) in different organisms to be compared directly. The efficiency of these biological applications is directly related to the design of the shared database. We classified and analyzed the different kinds of access to the database. Based on this study, we tried to adjust and tune the configurable parameters of the database server to reach the best performance of the communication data link to/from the database system. Different database technologies were analyzed. We started the study with a public relational SQL database, MySQL. Then, the same database was implemented by a MapReduce-based database named HBase. The results indicated that the standard configuration of MySQL gives an acceptable performance for low or medium size databases. Nevertheless, tuning database parameters can greatly improve the performance and lead to very competitive runtimes.
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Robery S, Tyson R, Dinh C, Kuspa A, Noegel AA, Bretschneider T, Andrews PLR, Williams RSB. A novel human receptor involved in bitter tastant detection identified using Dictyostelium discoideum. J Cell Sci 2013; 126:5465-76. [PMID: 24006265 PMCID: PMC4376016 DOI: 10.1242/jcs.136440] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 08/15/2013] [Indexed: 12/19/2022] Open
Abstract
Detection of substances tasting bitter to humans occurs in diverse organisms including the social amoeba Dictyostelium discoideum. To establish a molecular mechanism for bitter tastant detection in Dictyostelium, we screened a mutant library for resistance to a commonly used bitter standard, phenylthiourea. This approach identified a G-protein-coupled receptor mutant, grlJ(-), which showed a significantly increased tolerance to phenylthiourea in growth, survival and movement. This mutant was not resistant to a structurally dissimilar potent bitter tastant, denatonium benzoate, suggesting it is not a target for at least one other bitter tastant. Analysis of the cell-signalling pathway involved in the detection of phenylthiourea showed dependence upon heterotrimeric G protein and phosphatidylinositol 3-kinase activity, suggesting that this signalling pathway is responsible for the cellular effects of phenylthiourea. This is further supported by a phenylthiourea-dependent block in the transient cAMP-induced production of phosphatidylinositol (3,4,5)-trisphosphate (PIP3) in wild-type but not grlJ(-) cells. Finally, we have identified an uncharacterized human protein γ-aminobutyric acid (GABA) type B receptor subunit 1 isoform with weak homology to GrlJ that restored grlJ(-) sensitivity to phenylthiourea in cell movement and PIP3 regulation. Our results thus identify a novel pathway for the detection of the standard bitter tastant phenylthiourea in Dictyostelium and implicate a poorly characterized human protein in phenylthiourea-dependent cell responses.
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Affiliation(s)
- Steven Robery
- Centre for Biomedical Sciences, School of Biological Sciences, Royal Holloway University of London, Egham TW20 0EX, UK
| | - Richard Tyson
- Warwick Systems Biology Centre, University of Warwick, Coventry CV4 7AL, UK
| | - Christopher Dinh
- Department of Biochemistry and Molecular Biology, Baylor College of Medicine, Houston, Texas 77030, USA
| | - Adam Kuspa
- Department of Biochemistry and Molecular Biology, Baylor College of Medicine, Houston, Texas 77030, USA
| | - Angelika A. Noegel
- Institute of Biochemistry I, Medical Faculty, University of Cologne, Cologne, Germany
| | - Till Bretschneider
- Warwick Systems Biology Centre, University of Warwick, Coventry CV4 7AL, UK
| | - Paul L. R. Andrews
- Division of Biomedical Sciences, St George's University of London, London SW17 0RE, UK
| | - Robin S. B. Williams
- Centre for Biomedical Sciences, School of Biological Sciences, Royal Holloway University of London, Egham TW20 0EX, UK
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Winterhoff M, Junemann A, Nordholz B, Linkner J, Schleicher M, Faix J. The Diaphanous-related formin dDia1 is required for highly directional phototaxis and formation of properly sized fruiting bodies in Dictyostelium. Eur J Cell Biol 2013; 93:212-24. [PMID: 24331584 DOI: 10.1016/j.ejcb.2013.11.002] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2013] [Revised: 11/12/2013] [Accepted: 11/14/2013] [Indexed: 11/17/2022] Open
Abstract
Diaphanous-related formins (DRFs) act as downstream effectors of Rho family GTPases and drive the formation and elongation of linear actin filaments in various cellular processes. Here we analyzed the DRF dDia1 from Dictyostelium cells. The biochemical characterization of recombinant dDia1-FH1FH2 by bulk polymerization assays and single filament TIRF microscopy revealed that dDia1 is a rather weak nucleator. Addition of any of the three Dictyostelium profilin isoforms, however, markedly accelerated formin-mediated actin filament barbed end elongation in TIRF assays. Interestingly, filament elongation was significantly faster in presence of DdPFN I (profilin I) when compared to the other two isoforms, suggesting selectivity of dDia1 for DdPFN I. Additionally, we frequently observed dissociation of the formin from growing barbed ends. These findings are consistent with dilution-induced depolymerization assays in presence of dDia1-FH1FH2 showing that dDia1 is a weak capper in comparison with heterodimeric capping protein. To study the physiological role of this formin, we created cell lines lacking dDia1 or overexpressing GFP-tagged dDia1. Of note, constitutively active dDia1 accumulated homogenously in the entire pseudopod suggesting that it controls microfilament architecture to regulate cell migration. Comparison of wild type and dDia1-null cells in random cell migration and chemotaxis toward a cAMP gradient revealed no major differences. By contrast, phototaxis of dDia1-deficient cells during the multicellular stage was markedly impaired. While wild type slugs moved with high directionality toward the light source, the trails of dDia1-null slugs displayed a characteristic V-shaped profile and deviated in angles between 50° and 60° from the path of the incident light. Possibly in conjunction with this defect, dDia1-null cells also formed substantially smaller fruiting bodies. These findings demonstrate dDia1 to be critically involved in collective cell migration during terminal differentiation.
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Affiliation(s)
- Moritz Winterhoff
- Institute for Biophysical Chemistry, Hannover Medical School, Carl-Neuberg Straße 1, 30625 Hannover, Germany
| | - Alexander Junemann
- Institute for Biophysical Chemistry, Hannover Medical School, Carl-Neuberg Straße 1, 30625 Hannover, Germany
| | - Benjamin Nordholz
- Institute for Biophysical Chemistry, Hannover Medical School, Carl-Neuberg Straße 1, 30625 Hannover, Germany
| | - Jörn Linkner
- Institute for Biophysical Chemistry, Hannover Medical School, Carl-Neuberg Straße 1, 30625 Hannover, Germany
| | - Michael Schleicher
- Institute for Anatomy and Cell Biology, Ludwig-Maximilians-University, 80336 München, Germany
| | - Jan Faix
- Institute for Biophysical Chemistry, Hannover Medical School, Carl-Neuberg Straße 1, 30625 Hannover, Germany.
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15
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Brzostowski JA, Sawai S, Rozov O, Liao XH, Imoto D, Parent CA, Kimmel AR. Phosphorylation of chemoattractant receptors regulates chemotaxis, actin reorganization and signal relay. J Cell Sci 2013; 126:4614-26. [PMID: 23902692 PMCID: PMC3795335 DOI: 10.1242/jcs.122952] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023] Open
Abstract
Migratory cells, including mammalian leukocytes and Dictyostelium, use G-protein-coupled receptor (GPCR) signaling to regulate MAPK/ERK, PI3K, TORC2/AKT, adenylyl cyclase and actin polymerization, which collectively direct chemotaxis. Upon ligand binding, mammalian GPCRs are phosphorylated at cytoplasmic residues, uncoupling G-protein pathways, but activating other pathways. However, connections between GPCR phosphorylation and chemotaxis are unclear. In developing Dictyostelium, secreted cAMP serves as a chemoattractant, with extracellular cAMP propagated as oscillating waves to ensure directional migratory signals. cAMP oscillations derive from transient excitatory responses of adenylyl cyclase, which then rapidly adapts. We have studied chemotactic signaling in Dictyostelium that express non-phosphorylatable cAMP receptors and show through chemotaxis modeling, single-cell FRET imaging, pure and chimeric population wavelet quantification, biochemical analyses and TIRF microscopy, that receptor phosphorylation is required to regulate adenylyl cyclase adaptation, long-range oscillatory cAMP wave production and cytoskeletal actin response. Phosphorylation defects thus promote hyperactive actin polymerization at the cell periphery, misdirected pseudopodia and the loss of directional chemotaxis. Our data indicate that chemoattractant receptor phosphorylation is required to co-regulate essential pathways for migratory cell polarization and chemotaxis. Our results significantly extend the understanding of the function of GPCR phosphorylation, providing strong evidence that this evolutionarily conserved mechanism is required in a signal attenuation pathway that is necessary to maintain persistent directional movement of Dictyostelium, neutrophils and other migratory cells.
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Affiliation(s)
- Joseph A Brzostowski
- Laboratory of Immunogenetics Imaging Facility, NIAID/NIH, Rockville, MD 20852, USA
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16
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Brzostowski JA, Fey P, Yan J, Isik N, Jin T. The Elmo family forms an ancient group of actin-regulating proteins. Commun Integr Biol 2013; 2:337-40. [PMID: 19721884 DOI: 10.4161/cib.2.4.8549] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2009] [Accepted: 03/18/2009] [Indexed: 01/11/2023] Open
Abstract
The Elmo protein family members are important mediators of small G protein activity, regulating actin-mediated processes such as chemotaxis and engulfment. Until recently,1 Elmo function has not been explored in professional phagocytes such as Dictyostelium discoideum. We discuss the significance of this family with respect to pathways that regulate Rac signaling, we present a comparison of Elmo proteins between representative taxa, and discuss our findings on ElmoA, one of six Elmo proteins found in D. discoideum.
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Affiliation(s)
- Joseph A Brzostowski
- Laboratory of Immunogenetics Imaging Facility; National Institutes of Health; Rockville, MD USA
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17
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Bozzaro S, Peracino B, Eichinger L. Dictyostelium host response to legionella infection: strategies and assays. Methods Mol Biol 2013; 954:417-38. [PMID: 23150412 DOI: 10.1007/978-1-62703-161-5_26] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
Abstract
The professional phagocyte Dictyostelium discoideum is a simple eukaryotic microorganism, whose natural habitat is deciduous forest soil and decaying leaves, where the amoebae feed on bacteria and grow as separate, independent, single cells. In the last decade, the organism has been successfully used as a host for several human pathogens, including Legionella pneumophila, Mycobacterium avium and Mycobacterium marinum,Pseudomonas aeruginosa, Klebsiella pneumoniae, Cryptococcus neoformans, and Salmonella typhimurium. To dissect the complex cross-talk between host and pathogen Dictyostelium offers easy cultivation, a high quality genome sequence and excellent molecular genetic and biochemical tools. Dictyostelium cells are also extremely suitable for cell biological studies, which in combination with in vivo expression of fluorescence-tagged proteins allow investigating the dynamics of bacterial uptake and infection. Inactivation of genes by homologous recombination as well as gene rescue and overexpression are well established and a large mutant collection is available at the Dictyostelium stock center, favoring identification of host resistance or susceptibility genes. Here, we briefly introduce the organism, address the value of Dictyostelium as model host, describe strategies to identify host cell factors important for infection followed by protocols for cell culture and storage, uptake and infection, and confocal microscopy of infected cells.
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Affiliation(s)
- Salvatore Bozzaro
- Department of Clinical and Biological Sciences, University of Turin, Orbassano, Italy,
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Ye T, Tang W, Zhang X. Involvement of Rab6 in the regulation of phagocytosis against virus infection in invertebrates. J Proteome Res 2012; 11:4834-46. [PMID: 22928698 DOI: 10.1021/pr300274k] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
Phagocytosis, which is of fundamental importance for innate and adaptive immunity in animals, is driven by organization of the actin cytoskeleton. To date, however, the molecular events involved in the regulation of phagocytosis through reorganization of actin by small G proteins remains to be elucidated. To address this issue, the molecular mechanism of Rab6 in phagocytosis against virus infection in invertebrates was characterized in this study. The results showed that the Rab6 obtained from shrimp could interact with actin to regulate shrimp hemocyte phagocytosis through induction of the rearrangement of actin to protect against white spot syndrome virus (WSSV) infection. The Rab6 protein in Drosophila melanogaster shared the same mechanism of action as that of Rab6 in shrimp, indicating that the function of Rab6 in phagocytosis was conserved in invertebrates. By comparison with the early marker (Rab5) and late marker (LAMP1) of phagosomes, Rab6 was critically involved in the regulation of actin organization throughout the entire phagocytosis process. The presence of the evolutionarily conserved amino acid sequences of Rab6 in invertebrates and vertebrates indicated a conserved mechanism of Rab6 function in phagocytosis of animals. Therefore, our findings presented novel molecular events in the regulation of phagocytosis by small G proteins.
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Affiliation(s)
- Ting Ye
- Key Laboratory of Conservation Biology for Endangered Wildlife of the Ministry of Education, Key Laboratory of Animal Virology of Ministry of Agriculture and College of Life Sciences, Zhejiang University, Hangzhou 310058, The People's Republic of China
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Cell Migration: Regulation of cytoskeleton by Rap1 in Dictyostelium discoideum. J Microbiol 2012; 50:555-61. [PMID: 22923101 DOI: 10.1007/s12275-012-2246-7] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2012] [Accepted: 06/29/2012] [Indexed: 10/28/2022]
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Xu X, Jin T. A shortcut from GPCR signaling to Rac-mediated actin cytoskeleton through an ELMO/DOCK complex. Small GTPases 2012; 3:183-5. [PMID: 22647486 PMCID: PMC3442806 DOI: 10.4161/sgtp.20271] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
Chemotaxis, chemoattractant-guided directional cell migration, plays major roles in human innate immunity and in development of a model organism Dictyostelium discoideum. Human leukocytes and D. disscoideum share remarkable similarities in the molecular mechanisms that control chemotaxis. These cells use G-Protein-Coupled Receptors (GPCRs), such as chemokine receptors, to control a signaling network that carries out chemotactic gradient sensing and directs cell migration. Diverse chemokines bind to their receptors to activate small G protein Rac through an evolutionarily conserved mechanism. Elmo and Dock180 proteins form ELMO/Dock180 complexes functioning as guanine nucleotide exchange factors (GEFs) for Rac activation. However, the linkage between GPCR to Elmo/Dock180 for Rac activation that controls F-actin dynamics remained unclear. Recently, we discovered a novel function of an ELMO protein in Dictyostelium discoideum linking GPCR signaling from Gβ to actin dynamics through regulating Rac activation during chemotaxis.
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Affiliation(s)
- Xuehua Xu
- Chemotaxis Signal Section, Laboratory of Immunogenetics, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Rockville, MD, USA.
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Wang CJ, Bergmann A, Lin B, Kim K, Levchenko A. Diverse sensitivity thresholds in dynamic signaling responses by social amoebae. Sci Signal 2012; 5:ra17. [PMID: 22375055 DOI: 10.1126/scisignal.2002449] [Citation(s) in RCA: 75] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
The complex transition from a single-cell to a multicellular life form during the formation of a fruiting body by the amoeba Dictyostelium discoideum is accompanied by a pulsatile collective signaling process that instigates chemotaxis of the constituent cells. Although the cells used for the analysis of this phenomenon are normally genetically identical (isogenic), it is not clear whether they are equally responsive to the waves of the signaling stimulus, nor is it clear how responses across the population influence collective cell behavior. Here, we found that isogenic Dictyostelium cells displayed differing sensitivities to the chemoattractant cyclic adenosine monophosphate (cAMP). Furthermore, the resulting signaling responses could be explained by a model in which cells are refractory to further stimulation for 5 to 6 min after the initial input and the signaling output is amplified, with the amplification threshold varying across the cells in the population. This pathway structure could explain intracellular amplification of the chemoattractant gradient during cell migration. The new model predicts that diverse cell responsiveness can facilitate collective cell behavior, specifically due to the presence of a small number of cells in the population with increased responsiveness that aid in propagating the initial cAMP signaling wave across the cell population.
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Affiliation(s)
- C Joanne Wang
- Department of Biomedical Engineering, Johns Hopkins University, 3400 North Charles Street, Clark Hall Room 207, Baltimore, MD 21218, USA
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Abstract
Autophagy provides a mechanism for the turnover of cellular organelles and proteins through a lysosome-dependent degradation pathway. During starvation, autophagy exerts a homeostatic function that promotes cell survival by recycling metabolic precursors. Additionally, autophagy can interact with other vital processes such as programmed cell death, inflammation, and adaptive immune mechanisms, and thereby potentially influence disease pathogenesis. Macrophages deficient in autophagic proteins display enhanced caspase-1-dependent proinflammatory cytokine production and the activation of the inflammasome. Autophagy provides a functional role in infectious diseases and sepsis by promoting intracellular bacterial clearance. Mutations in autophagy-related genes, leading to loss of autophagic function, have been implicated in the pathogenesis of Crohn's disease. Furthermore, autophagy-dependent mechanisms have been proposed in the pathogenesis of several pulmonary diseases that involve inflammation, including cystic fibrosis and pulmonary hypertension. Strategies aimed at modulating autophagy may lead to therapeutic interventions for diseases associated with inflammation.
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Fauvarque MO, Williams MJ. Drosophila cellular immunity: a story of migration and adhesion. J Cell Sci 2011; 124:1373-82. [PMID: 21502134 DOI: 10.1242/jcs.064592] [Citation(s) in RCA: 66] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023] Open
Abstract
Research during the past 15 years has led to significant breakthroughs, providing evidence of a high degree of similarity between insect and mammalian innate immune responses, both humoural and cellular, and highlighting Drosophila melanogaster as a model system for studying the evolution of innate immunity. In a manner similar to cells of the mammalian monocyte and macrophage lineage, Drosophila immunosurveillance cells (haemocytes) have a number of roles. For example, they respond to wound signals, are involved in wound healing and contribute to the coagulation response. Moreover, they participate in the phagocytosis and encapsulation of invading pathogens, are involved in the removal of apoptotic bodies and produce components of the extracellular matrix. There are several reasons for using the Drosophila cellular immune response as a model to understand cell signalling during adhesion and migration in vivo: many genes involved in the regulation of Drosophila haematopoiesis and cellular immunity have been maintained across taxonomic groups ranging from flies to humans, many aspects of Drosophila and mammalian innate immunity seem to be conserved, and Drosophila is a simplified and well-studied genetic model system. In the present Commentary, we will discuss what is known about cellular adhesion and migration in the Drosophila cellular immune response, during both embryonic and larval development, and where possible compare it with related mechanisms in vertebrates.
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Affiliation(s)
- Marie-Odile Fauvarque
- Institut de Recherches en Technologies et Sciences pour le Vivant, Grenoble, France.
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Investigating the effect of emetic compounds on chemotaxis in Dictyostelium identifies a non-sentient model for bitter and hot tastant research. PLoS One 2011; 6:e24439. [PMID: 21931717 PMCID: PMC3169598 DOI: 10.1371/journal.pone.0024439] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2011] [Accepted: 08/10/2011] [Indexed: 01/05/2023] Open
Abstract
Novel chemical entities (NCEs) may be investigated for emetic liability in a range of unpleasant experiments involving retching, vomiting or conditioned taste aversion/food avoidance in sentient animals. We have used a range of compounds with known emetic /aversive properties to examine the possibility of using the social amoeba, Dictyostelium discoideum, for research into identifying and understanding emetic liability, and hence reduce adverse animal experimentation in this area. Twenty eight emetic or taste aversive compounds were employed to investigate the acute (10 min) effect of compounds on Dictyostelium cell behaviour (shape, speed and direction of movement) in a shallow chemotaxic gradient (Dunn chamber). Compound concentrations were chosen based on those previously reported to be emetic or aversive in in vivo studies and results were recorded and quantified by automated image analysis. Dictyostelium cell motility was rapidly and strongly inhibited by four structurally distinct tastants (three bitter tasting compounds--denatonium benzoate, quinine hydrochloride, phenylthiourea, and the pungent constituent of chilli peppers--capsaicin). In addition, stomach irritants (copper chloride and copper sulphate), and a phosphodiesterase IV inhibitor also rapidly blocked movement. A concentration-dependant relationship was established for five of these compounds, showing potency of inhibition as capsaicin (IC(50) = 11.9 ± 4.0 µM) > quinine hydrochloride (IC(50) = 44.3 ± 6.8 µM) > denatonium benzoate (IC(50) = 129 ± 4 µM) > phenylthiourea (IC(50) = 366 ± 5 µM) > copper sulphate (IC(50) = 1433 ± 3 µM). In contrast, 21 compounds within the cytotoxic and receptor agonist/antagonist classes did not affect cell behaviour. Further analysis of bitter and pungent compounds showed that the effect on cell behaviour was reversible and not cytotoxic, suggesting an uncharacterised molecular mechanism of action for these compounds. These results therefore demonstrate that Dictyostelium has potential as a non-sentient model in the analysis of the molecular effects of tastants, although it has limited utility in identification of emetic agents in general.
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Bozzaro S, Eichinger L. The professional phagocyte Dictyostelium discoideum as a model host for bacterial pathogens. Curr Drug Targets 2011; 12:942-54. [PMID: 21366522 PMCID: PMC3267156 DOI: 10.2174/138945011795677782] [Citation(s) in RCA: 81] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2010] [Accepted: 10/26/2010] [Indexed: 01/24/2023]
Abstract
The use of simple hosts such as Dictyostelium discoideum in the study of host pathogen interactions offers a number of advantages and has steadily increased in recent years. Infection-specific genes can often only be studied in a very limited way in man and even in the mouse model their analysis is usually expensive, time consuming and technically challenging or sometimes even impossible. In contrast, their functional analysis in D. discoideum and other simple model organisms is often easier, faster and cheaper. Because host-pathogen interactions necessarily involve two organisms, it is desirable to be able to genetically manipulate both the pathogen and its host. Particularly suited are those hosts, like D. discoideum, whose genome sequence is known and annotated and for which excellent genetic and cell biological tools are available in order to dissect the complex crosstalk between host and pathogen. The review focusses on host-pathogen interactions of D. discoideum with Legionella pneumophila, mycobacteria, and Salmonella typhimurium which replicate intracellularly.
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Affiliation(s)
- Salvatore Bozzaro
- Department of Clinical and Biological Sciences, University of Turin, Ospedale S. Luigi, 10043 Orbassano, Italy.
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Abstract
Chemotaxis of tumour cells and stromal cells in the surrounding microenvironment is an essential component of tumour dissemination during progression and metastasis. This Review summarizes how chemotaxis directs the different behaviours of tumour cells and stromal cells in vivo, how molecular pathways regulate chemotaxis in tumour cells and how chemotaxis choreographs cell behaviour to shape the tumour microenvironment and to determine metastatic spread. The central importance of chemotaxis in cancer progression is highlighted by discussion of the use of chemotaxis as a prognostic marker, a treatment end point and a target of therapeutic intervention.
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Affiliation(s)
- Evanthia T Roussos
- Department of Anatomy and Structural Biology, Program in Tumor Microenvironment and Metastasis, Albert Einstein College of Medicine of Yeshiva University, Bronx, New York 10461, USA
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Tyrosine phosphorylation-mediated signaling pathways in dictyostelium. JOURNAL OF SIGNAL TRANSDUCTION 2011; 2011:894351. [PMID: 21776390 PMCID: PMC3135261 DOI: 10.1155/2011/894351] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/27/2010] [Accepted: 02/21/2011] [Indexed: 01/21/2023]
Abstract
While studies on metazoan cell proliferation, cell differentiation, and cytokine signaling laid the foundation of the current paradigms of tyrosine kinase signaling, similar studies using lower eukaryotes have provided invaluable insight for the understanding of mammalian pathways, such as Wnt and STAT pathways. Dictyostelium is one of the leading lower eukaryotic model systems where stress-induced cellular responses, Wnt-like pathways, and STAT-mediated pathways are well investigated. These Dictyostelium pathways will be reviewed together with their mammalian counterparts to facilitate the comparative understanding of these variant and noncanonical pathways.
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Karathia H, Vilaprinyo E, Sorribas A, Alves R. Saccharomyces cerevisiae as a model organism: a comparative study. PLoS One 2011; 6:e16015. [PMID: 21311596 PMCID: PMC3032731 DOI: 10.1371/journal.pone.0016015] [Citation(s) in RCA: 95] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2010] [Accepted: 12/03/2010] [Indexed: 02/04/2023] Open
Abstract
BACKGROUND Model organisms are used for research because they provide a framework on which to develop and optimize methods that facilitate and standardize analysis. Such organisms should be representative of the living beings for which they are to serve as proxy. However, in practice, a model organism is often selected ad hoc, and without considering its representativeness, because a systematic and rational method to include this consideration in the selection process is still lacking. METHODOLOGY/PRINCIPAL FINDINGS In this work we propose such a method and apply it in a pilot study of strengths and limitations of Saccharomyces cerevisiae as a model organism. The method relies on the functional classification of proteins into different biological pathways and processes and on full proteome comparisons between the putative model organism and other organisms for which we would like to extrapolate results. Here we compare S. cerevisiae to 704 other organisms from various phyla. For each organism, our results identify the pathways and processes for which S. cerevisiae is predicted to be a good model to extrapolate from. We find that animals in general and Homo sapiens in particular are some of the non-fungal organisms for which S. cerevisiae is likely to be a good model in which to study a significant fraction of common biological processes. We validate our approach by correctly predicting which organisms are phenotypically more distant from S. cerevisiae with respect to several different biological processes. CONCLUSIONS/SIGNIFICANCE The method we propose could be used to choose appropriate substitute model organisms for the study of biological processes in other species that are harder to study. For example, one could identify appropriate models to study either pathologies in humans or specific biological processes in species with a long development time, such as plants.
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Affiliation(s)
- Hiren Karathia
- Departament Ciències Mèdiques Bàsiques, Universitat de Lleida & IRBLleida, Lleida, Spain
| | - Ester Vilaprinyo
- Evaluation and Clinical Epidemiology Department, Hospital del Mar-IMIM, Barcelona, Spain
| | - Albert Sorribas
- Departament Ciències Mèdiques Bàsiques, Universitat de Lleida & IRBLleida, Lleida, Spain
| | - Rui Alves
- Departament Ciències Mèdiques Bàsiques, Universitat de Lleida & IRBLleida, Lleida, Spain
- * E-mail:
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Sapey E, Stockley JA, Greenwood H, Ahmad A, Bayley D, Lord JM, Insall RH, Stockley RA. Behavioral and structural differences in migrating peripheral neutrophils from patients with chronic obstructive pulmonary disease. Am J Respir Crit Care Med 2011; 183:1176-86. [PMID: 21257786 DOI: 10.1164/rccm.201008-1285oc] [Citation(s) in RCA: 124] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022] Open
Abstract
RATIONALE There are increased neutrophils in the lungs of patients with chronic obstructive pulmonary disease (COPD), but it is unclear if this is due to increased inflammatory signal or related to the inherent behavior of the neutrophils. This is critical, because inaccurate or excessive neutrophil chemotaxis could drive pathological accumulation and tissue damage. OBJECTIVES To assess migratory dynamics of neutrophils isolated from patients with COPD compared with healthy smoking and nonsmoking control subjects and patients with α(1)-antitryspin deficiency. METHODS Migratory dynamics and structure were assessed in circulating neutrophils, using phase and differential interference contrast microscopy and time-lapse photography. The effect of COPD severity was studied. Surface expression of receptors was measured using flow cytometry. The in vitro effects of a phosphoinositide 3-kinase inhibitor (LY294002) were studied. MEASUREMENTS AND MAIN RESULTS COPD neutrophils moved with greater speed than cells from either control group but with reduced migratory accuracy, in the presence of IL-8, growth-related oncogene α, formyl-methionyl-leucyl-phenylalanine, and sputum. This was present across all stages of COPD. Structurally, COPD neutrophils formed fewer pseudopods during migration. There were no differences in surface expression of the receptors CXCR1, CXCR2, or FPR1. LY294002 reduced COPD neutrophil migratory speed while increasing chemotactic accuracy, returning values to normal. The inhibitor did not have these effects in healthy control subjects or patients with a similar degree of lung disease. CONCLUSIONS COPD neutrophils are intrinsically different than cells from other studied populations in their chemotactic behavior and migratory structure. Differences are not due to surface expression of chemoattractant receptors but instead appear to be due to differences in cell signaling.
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Affiliation(s)
- Elizabeth Sapey
- Department of Clinical and Experimental Medicine, First Floor, Nuffield House, University of Birmingham, Edgbaston, Birmingham B15 2TH, UK.
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Sim S, Yu JR, Lee YA, Shin MH. Involvement of Src family tyrosine kinase in apoptosis of human neutrophils induced by protozoan parasite Entamoeba histolytica. THE KOREAN JOURNAL OF PARASITOLOGY 2011; 48:285-90. [PMID: 21234229 PMCID: PMC3018576 DOI: 10.3347/kjp.2010.48.4.285] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/24/2010] [Revised: 10/13/2010] [Accepted: 10/13/2010] [Indexed: 11/23/2022]
Abstract
Tyrosine kinases are one of the most important regulators for intracellular signal transduction related to inflammatory responses. However, there are no reports describing the effects of tyrosine kinases on neutrophil apoptosis induced by Entamoeba histolytica. In this study, isolated human neutrophils from peripheral blood were incubated with live trophozoites in the presence or absence of tyrosine kinase inhibitors. Entamoeba-induced receptor shedding of CD16 and PS externalization in neutrophils were inhibited by pre-incubation of neutrophils with the broad-spectrum tyrosine kinase inhibitor genistein or the Src family kinase inhibitor PP2. Entamoeba-induced ROS production was also inhibited by genistein or PP2. Moreover, genistein and PP2 blocked the phosphorylation of ERK and p38 MAPK in neutrophils induced by E. histolytica. These results suggest that Src tyrosine kinases may participate in the signaling event for ROS-dependent activation of MAPKs during neutrophil apoptosis induced by E. histolytica.
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Affiliation(s)
- Seobo Sim
- Department of Environmental and Tropical Medicine, Konkuk University, Chungju 380-701, Korea
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Nhe1 is essential for potassium but not calcium facilitation of cell motility and the monovalent cation requirement for chemotactic orientation in Dictyostelium discoideum. EUKARYOTIC CELL 2011; 10:320-31. [PMID: 21239624 DOI: 10.1128/ec.00255-10] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
In Dictyostelium discoideum, extracellular K+ or Ca2+ at a concentration of 40 or 20 mM, respectively, facilitates motility in the absence or presence of a spatial gradient of chemoattractant. Facilitation results in maximum velocity, cellular elongation, persistent translocation, suppression of lateral pseudopod formation, and myosin II localization in the posterior cortex. A lower threshold concentration of 15 mM K+ or Na or 5 mM Ca2+ is required for chemotactic orientation. Although the common buffer solutions used by D. discoideum researchers to study chemotaxis contain sufficient concentrations of cations for chemotactic orientation, the majority contain insufficient levels to facilitate motility. Here it has been demonstrated that Nhe1, a plasma membrane protein, is required for K+ but not Ca2+ facilitation of cell motility and for the lower K+ but not Ca2+ requirement for chemotactic orientation.
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Abstract
SummaryAgeing is associated with multiple changes in many different components of the immune system. A healthy immune system exists in a state of balance between efficient effector responses against pathogens and tolerance to self antigens. This balance is changed with age; functions such as antigen recognition, phagocytosis, antigen presentation, chemotaxis, cytokine secretion and killing ability are all compromised. Aberrant cellular responses lead to an altered cytokine network with increases in inflammatory cytokines and decreases in anti-inflammatory cytokines leading to a pro-inflammatory state. Consequently older patients require extra care in diagnosis of infections as symptoms may be perturbed, resulting in unusual presentations of common conditions. The defects in immunity due to immunosenescence also mean that older patients require more care and screening than other patients in the same disease cohort. Though it is generally understood by clinicians that older patients are more at risk from multiple infections, the wider clinical effects of immunosenescence are less understood. The immune system is involved in several neurodegenerative conditions and the inflammatory conditions of immunosenescence may be a key factor in pathogenesis. Similarly, there is reason to believe that immunosenescence might be a key factor explaining the increased incidence of cancer in older age. With increasing understanding of the immune system's involvement in many of these pathological processes, and the contribution that immunosenescence makes to these, more efficient vaccines and novel therapies may be developed to prevent/treat these conditions.
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Scherer A, Kuhl S, Wessels D, Lusche DF, Raisley B, Soll DR. Ca2+ chemotaxis in Dictyostelium discoideum. J Cell Sci 2010; 123:3756-67. [PMID: 20940253 DOI: 10.1242/jcs.068619] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023] Open
Abstract
Using a newly developed microfluidic chamber, we have demonstrated in vitro that Ca(2+) functions as a chemoattractant of aggregation-competent Dictyostelium discoideum amoebae, that parallel spatial gradients of cAMP and Ca(2+) are more effective than either alone, and that cAMP functions as a stronger chemoattractant than Ca(2+). Effective Ca(2+) gradients are extremely steep compared with effective cAMP gradients. This presents a paradox because there is no indication to date that steep Ca(2+) gradients are generated in aggregation territories. However, given that Ca(2+) chemotaxis is co-acquired with cAMP chemotaxis during development, we speculate on the role that Ca(2+) chemotaxis might have and the possibility that steep, transient Ca(2+) gradients are generated during natural aggregation in the interstitial regions between cells.
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Affiliation(s)
- Amanda Scherer
- The W. M. Keck Dynamic Image Analysis Facility, Department of Biology, The University of Iowa, Iowa City, IA 52242, USA
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Catalano A, Luo W, Wang Y, O'Day DH. Synthesis and biological activity of peptides equivalent to the IP22 repeat motif found in proteins from Dictyostelium and Mimivirus. Peptides 2010; 31:1799-805. [PMID: 20624437 DOI: 10.1016/j.peptides.2010.07.005] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/22/2010] [Revised: 07/03/2010] [Accepted: 07/05/2010] [Indexed: 11/24/2022]
Abstract
A novel IP22 repeat motif of unknown function was discovered previously that comprises almost the entire structure of cmbB, a calmodulin-binding protein from Dictyostelium discoideum. An analysis of over 2000 IP22 repeats across 130 different proteins from different species allowed us to define a prototypical IP22 repeat: I/LPxxhxxhxhxxxhxxxhxxxx (where L=leucine, I=isoleucine, h=any hydrophobic amino acid, x=any amino acid). Here we describe the synthesis of three peptide variants of the IP22 motif: IP22-1 (IPNSVTSLKFGDGFNQPLTPGT; 22aa); IP22-2 (LPSTLKTISLSNSTDKKIFKNS; 22aa); and, IP22-3 (IPKSLRSLFLGKGYNQPLEF; 20aa) plus a control peptide from the N-term of cmbB (HNMNPFSPQLDEKKNSHIVEY; 21aa). The structure and purity of synthesized peptides were verified by HPLC and mass spectrometry. The peptides all dose-dependently enhanced random cell motility and cAMP-mediated chemotaxis in Dictyostelium but IP22-3 was most effective peaking in activity around 50 μM. Fluorescein isothiocyanate (FITC)-conjugated IP22 peptides did not penetrate cells suggesting these peptides affect cell motility via cell surface interactions. Treatment of cells with FITC-IP22 peptides also led to enhanced cell motility equivalent to the non-conjugated peptides. Treatment of IP22-3-stimulated cells with 50 μM LY294002, 20 μM quinacrine or both suggests that IP22-3 requires both phosphoinositol 3-kinase and phospholipase A2 signaling to elicit its effects, a mechanism unique from EGFL motility enhancing peptides. The mechanism of action and potential uses of IP22 repeat peptides are discussed.
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Affiliation(s)
- Andrew Catalano
- Department of Cell and Systems Biology, University of Toronto, 25 Harbord st., Toronto, Ontario, Canada, M5S 3G5
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Xu X, Meckel T, Brzostowski JA, Yan J, Meier-Schellersheim M, Jin T. Coupling mechanism of a GPCR and a heterotrimeric G protein during chemoattractant gradient sensing in Dictyostelium. Sci Signal 2010; 3:ra71. [PMID: 20876874 DOI: 10.1126/scisignal.2000980] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
Abstract
The coupling of heterotrimeric guanine nucleotide-binding protein (G protein)-coupled receptors (GPCRs) with G proteins is fundamental for GPCR signaling; however, the mechanism of coupling is still debated. Moreover, how the proposed mechanisms affect the dynamics of downstream signaling remains unclear. Here, through experiments involving fluorescence recovery after photobleaching and single-molecule imaging, we directly measured the mobilities of cyclic adenosine monophosphate (cAMP) receptor 1 (cAR1), a chemoattractant receptor, and a G protein βγ subunit in live cells. We found that cAR1 diffused more slowly in the plasma membrane than did Gβγ. Upon binding of ligand to the receptor, the mobility of cAR1 was unchanged, whereas the speed of a fraction of the faster-moving Gβγ subunits decreased. Our measurements showed that cAR1 was relatively immobile and Gβγ diffused freely, suggesting that chemoattractant-bound cAR1 transiently interacted with G proteins. Using models of possible coupling mechanisms, we computed the temporal kinetics of G protein activation. Our fluorescence resonance energy transfer imaging data showed that fully activated cAR1 induced the sustained dissociation of G protein α and βγ subunits, which indicated that ligand-bound cAR1 activated G proteins continuously. Finally, simulations indicated that a high-affinity coupling of ligand-bound receptors and G proteins was essential for cAR1 to translate extracellular gradient signals into directional cellular responses. We suggest that chemoattractant receptors use a ligand-induced coupling rather than a precoupled mechanism to control the activation of G proteins during chemotaxis.
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Affiliation(s)
- Xuehua Xu
- Chemotaxis Signal Section, National Institutes of Health, Rockville, MD 20852, USA
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Shina MC, Unal C, Eichinger L, Müller-Taubenberger A, Schleicher M, Steinert M, Noegel AA. A Coronin7 homolog with functions in actin-driven processes. J Biol Chem 2010; 285:9249-61. [PMID: 20071332 DOI: 10.1074/jbc.m109.083725] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Dictyostelium discoideum Coronin7 (DdCRN7) together with human Coronin7 (CRN7) and Pod-1 of Drosophila melanogaster and Caenorhabditis elegans belong to the coronin family of WD-repeat domain-containing proteins. Coronin7 proteins are characterized by two WD-repeat domains that presumably fold into two beta-propeller structures. DdCRN7 shares highest homology with human CRN7, a protein with roles in membrane trafficking. DdCRN7 is present in the cytosol and accumulates in cell surface projections during movement and phago- and pinocytosis. Cells lacking CRN7 have altered chemotaxis and phagocytosis. Furthermore, loss of CRN7 affects the infection process by the pathogen Legionella pneumophila and allows a more efficient internalization of bacteria. To provide a mechanism for CNR7 action, we studied actin-related aspects. We could show that CRN7 binds directly to F-actin and protects actin filaments from depolymerization. CRN7 also associated with F-actin in vivo. It was present in the Triton X-100-insoluble cytoskeleton, colocalized with F-actin, and its distribution was sensitive to drugs affecting the actin cytoskeleton. We propose that the CRN7 role in chemotaxis and phagocytosis is through its effect on the actin cytoskeleton.
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Affiliation(s)
- Maria C Shina
- Institute for Biochemistry I, Center for Molecular Medicine Cologne and Cologne Excellence Cluster on Cellular Stress Responses in Aging-associated Diseases, Medical Faculty, University of Cologne, 50931 Koeln, Germany
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Tung SM, Ünal C, Ley A, Peña C, Tunggal B, Noegel AA, Krut O, Steinert M, Eichinger L. Loss of Dictyostelium ATG9 results in a pleiotropic phenotype affecting growth, development, phagocytosis and clearance and replication of Legionella pneumophila. Cell Microbiol 2010; 12:765-80. [DOI: 10.1111/j.1462-5822.2010.01432.x] [Citation(s) in RCA: 81] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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Mikami K, Li L, Takahashi M, Saga N. Photosynthesis-dependent Ca2+ influx and functional diversity between phospholipases in the formation of cell polarity in migrating cells of red algae. PLANT SIGNALING & BEHAVIOR 2009; 4:911-913. [PMID: 19938378 PMCID: PMC2802806 DOI: 10.4161/psb.4.9.9534] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/10/2009] [Accepted: 07/16/2009] [Indexed: 05/28/2023]
Abstract
Unicellular spore cells, designated as monospores (also called archeospores), are well known as migrating plant cells, in which establishment of the anterior-posterior axis directs asymmetrical distribution of F-actin. Since the mechanisms of cell polarity formation are not yet fully elucidated in monospores, we investigated the roles of phosphoinositide signaling systems and Ca2+ mobilization in migration. Although we have already found the critical involvement of phosphatidylinositol 3-kinase in the establishment of cell polarity, we recently demonstrated the important roles of extracellular Ca2+ influx, phospholipase C (PLC) and phospholipase D (PLD). The remarkable characteristics of these factors are that Ca2+ influx depends on photosynthetic activity and that PLC and PLD play roles in the establishment and maintenance of cell polarity, respectively. These findings could provide new insight into the regulation of migration in eukaryotic cells.
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Affiliation(s)
- Koji Mikami
- Faculty of Fisheries Sciences, Hokkaido University, Hakodate, Japan.
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Annesley SJ, Fisher PR. Dictyostelium discoideum--a model for many reasons. Mol Cell Biochem 2009; 329:73-91. [PMID: 19387798 DOI: 10.1007/s11010-009-0111-8] [Citation(s) in RCA: 104] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2009] [Accepted: 04/02/2009] [Indexed: 10/25/2022]
Abstract
The social amoeba or cellular slime mould Dictyostelium discoideum is a "professional" phagocyte that has long been recognized for its value as a biomedical model organism, particularly in studying the actomyosin cytoskeleton and chemotactic motility in non-muscle cells. The complete genome sequence of D. discoideum is known, it is genetically tractable, readily grown clonally as a eukaryotic microorganism and is highly accessible for biochemical, cell biological and physiological studies. These are the properties it shares with other microbial model organisms. However, Dictyostelium combines these with a unique life style, with motile unicellular and multicellular stages, and multiple cell types that offer for study an unparalleled variety of phenotypes and associated signalling pathways. These advantages have led to its recent emergence as a valuable model organism for studying the molecular pathogenesis and treatment of human disease, including a variety of infectious diseases caused by bacterial and fungal pathogens. Perhaps surprisingly, this organism, without neurons or brain, has begun to yield novel insights into the cytopathology of mitochondrial diseases as well as other genetic and idiopathic disorders affecting the central nervous system. Dictyostelium has also contributed significantly to our understanding of NDP kinase, as it was the Dictyostelium enzyme whose structure was first determined and related to enzymatic activity. The phenotypic richness and tractability of Dictyostelium should provide a fertile arena for future exploration of NDPK's cellular roles.
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Affiliation(s)
- Sarah J Annesley
- Department of Microbiology, La Trobe University, Bundoora, VIC 3086, Australia
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