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Asante-Asamani E, Dalton M, Brazill D, Strychalski W. Modeling the dynamics of actin and myosin during bleb stabilization. bioRxiv 2023:2023.10.26.564082. [PMID: 37961169 PMCID: PMC10634845 DOI: 10.1101/2023.10.26.564082] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/15/2023]
Abstract
The actin cortex is very dynamic during migration of eukaryotes. In cells that use blebs as leading-edge protrusions, the cortex reforms beneath the cell membrane (bleb cortex) and completely disassembles at the site of bleb initiation. Remnants of the actin cortex at the site of bleb nucleation are referred to as the actin scar. We refer to the combined process of cortex reformation along with the degradation of the actin scar during bleb-based cell migration as bleb stabilization. The molecular factors that regulate the dynamic reorganization of the cortex are not fully understood. Myosin motor protein activity has been shown to be necessary for blebbing, with its major role associated with pressure generation to drive bleb expansion. Here, we examine the role of myosin in regulating cortex dynamics during bleb stabilization. Analysis of microscopy data from protein localization experiments in Dictyostelium discoideum cells reveals a rapid formation of the bleb's cortex with a delay in myosin accumulation. In the degrading actin scar, myosin is observed to accumulate before active degradation of the cortex begins. Through a combination of mathematical modeling and data fitting, we identify that myosin helps regulate the equilibrium concentration of actin in the bleb cortex during its reformation by increasing its dissasembly rate. Our modeling and analysis also suggests that cortex degradation is driven primarily by an exponential decrease in actin assembly rate rather than increased myosin activity. We attribute the decrease in actin assembly to the separation of the cell membrane from the cortex after bleb nucleation.
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Affiliation(s)
| | - Mackenzie Dalton
- Department of Mathematics, Clarkson University, Clarkson, Potsdam, NY 13699
| | | | - Wanda Strychalski
- Department of Mathematics, Applied Mathematics, and Statistics, Case Western Reserve University, Cleveland, OH 44106
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2
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Nishida HY, Hamada K, Koshita M, Ohta Y, Nishida H. Ascidian gastrulation and blebbing activity of isolated endoderm blastomeres. Dev Biol 2023; 496:24-35. [PMID: 36702215 DOI: 10.1016/j.ydbio.2023.01.007] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2022] [Revised: 01/16/2023] [Accepted: 01/20/2023] [Indexed: 01/24/2023]
Abstract
Gastrulation is the first dynamic cell movement during embryogenesis. Endoderm and mesoderm cells are internalized into embryos during this process. Ascidian embryos provide a simple system for studying gastrulation in chordates. Gastrulation starts in spherical late 64-cell embryos with 10 endoderm blastomeres. The mechanisms of gastrulation in ascidians have been investigated, and a two-step model has been proposed. The first step involves apical constriction of endoderm cells, followed by apicobasal shortening in the second step. In this study, isolated ascidian endoderm progenitor cells displayed dynamic blebbing activity at the gastrula stage, although such a dynamic cell-shape change was not recognized in toto. Blebbing is often observed in migrating animal cells. In ascidians, endoderm cells displayed blebbing activity, while mesoderm and ectoderm cells did not. The timing of blebbing of isolated endoderm cells coincided with that of cell invagination. The constriction rate of apical surfaces correlated with the intensity of blebbing activity in each endoderm-lineage cell. Fibroblast growth factor (FGF) signaling was both necessary and sufficient for inducing blebbing activity, independent of cell fate specification. In contrast, the timing of initiation of blebbing and intensity of blebbing response to FGF signaling were controlled by intrinsic cellular factors. It is likely that the difference in intensity of blebbing activity between the anterior A-line and posterior B-line cells could account for the anteroposterior difference in the steepness of the archenteron wall. Inhibition of zygotic transcription, FGF signaling, and Rho kinase, all of which suppressed blebbing activity, resulted in incomplete apical constriction and failure of the eventual formation of cup-shaped gastrulae. Blebbing activity was involved in the progression and maintenance of apical constriction, but not in apicobasal shortening in whole embryos. Apical constriction is mediated by distinct blebbing-dependent and blebbing-independent mechanisms. Surface tension and consequent membrane contraction may not be the sole mechanical force for apical constriction and formation of cup-shaped gastrulae. The present study reveals the hidden cellular potential of endodermal cells during gastrulation and discusses the possible roles of blebbing in the invagination process.
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Affiliation(s)
- Haruka Y Nishida
- Department of Biological Sciences, Graduate School of Science, Osaka University, Toyonaka, Osaka, 560-0043, Japan
| | - Kaho Hamada
- Department of Biological Sciences, Graduate School of Science, Osaka University, Toyonaka, Osaka, 560-0043, Japan
| | - Mika Koshita
- Department of Biological Sciences, Graduate School of Science, Osaka University, Toyonaka, Osaka, 560-0043, Japan
| | - Yuki Ohta
- Department of Biological Sciences, Graduate School of Science, Osaka University, Toyonaka, Osaka, 560-0043, Japan
| | - Hiroki Nishida
- Department of Biological Sciences, Graduate School of Science, Osaka University, Toyonaka, Osaka, 560-0043, Japan.
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O'Callaghan P, Engberg A, Eriksson O, Fatsis-Kavalopoulos N, Stelzl C, Sanchez G, Idevall-Hagren O, Kreuger J. Piezo1 activation attenuates thrombin-induced blebbing in breast cancer cells. J Cell Sci 2022; 135:274949. [PMID: 35274124 PMCID: PMC9016622 DOI: 10.1242/jcs.258809] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2021] [Accepted: 02/22/2022] [Indexed: 11/30/2022] Open
Abstract
Cancer cells exploit a variety of migration modes to leave primary tumors and establish metastases, including amoeboid cell migration, which is typically reliant on bleb formation. Here we demonstrate that thrombin induces dynamic blebbing in the MDA-MB-231 breast cancer cell line and confirm that protease-activated receptor 1 (PAR1) activation is sufficient to induce this effect. Cell confinement has been implicated as a driving force in bleb-based migration. Unexpectedly, we found that gentle contact compression, exerted using a custom built ‘cell press’ to mechanically stimulate cells, reduced thrombin-induced blebbing. Thrombin-induced blebbing was similarly attenuated using the small molecule Yoda1, an agonist of the mechanosensitive Ca2+ channel Piezo1, and this attenuation was impaired in Piezo1-depleted cells. Additionally, Piezo1 activation suppressed thrombin-induced phosphorylation of ezrin, radixin and moesin (ERM) proteins, which are implicated in the blebbing process. Our results provide mechanistic insights into Piezo1 activation as a suppressor of dynamic blebbing, specifically that which is induced by thrombin. Summary: Thrombin and protease-activated receptor agonists induce dynamic blebbing in breast cancer cells, which can be attenuated by contact-mediated compression, and activation of the mechanosensitive ion channel Piezo1.
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Affiliation(s)
- Paul O'Callaghan
- Department of Medical Cell Biology, Uppsala University, Uppsala, Sweden
| | - Adam Engberg
- Department of Medical Cell Biology, Uppsala University, Uppsala, Sweden
| | - Olle Eriksson
- Department of Medical Cell Biology, Uppsala University, Uppsala, Sweden
| | | | - Christina Stelzl
- Department of Medical Cell Biology, Uppsala University, Uppsala, Sweden
| | - Gonzalo Sanchez
- Department of Medical Cell Biology, Uppsala University, Uppsala, Sweden
| | | | - Johan Kreuger
- Department of Medical Cell Biology, Uppsala University, Uppsala, Sweden
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4
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Yang G, Hiruma S, Kitamura A, Kinjo M, Mishra M, Uehara R. Molecular basis of functional exchangeability between ezrin and other actin-membrane associated proteins during cytokinesis. Exp Cell Res 2021; 403:112600. [PMID: 33862101 DOI: 10.1016/j.yexcr.2021.112600] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2020] [Revised: 04/03/2021] [Accepted: 04/05/2021] [Indexed: 01/09/2023]
Abstract
The mechanism that mediates the interaction between the contractile ring and the plasma membrane during cytokinesis remains elusive. We previously found that ERM (Ezrin/Radixin/Moesin) proteins, which usually mediate cellular pole contraction, become over-accumulated at the cell equator and support furrow ingression upon the loss of other actin-membrane associated proteins, anillin and supervillin. In this study, we addressed the molecular basis of the exchangeability between ezrin and other actin-membrane associated proteins in mediating cortical contraction during cytokinesis. We found that depletion of anillin and supervillin caused over-accumulation of the membrane-associated FERM domain and actin-binding C-terminal domain (C-term) of ezrin at the cleavage furrow, respectively. This finding suggests that ezrin differentially shares its binding sites with these proteins on the actin cytoskeleton or inner membrane surface. Using chimeric mutants, we found that ezrin C-term, but not the FERM domain, can substitute for the corresponding anillin domains in cytokinesis and cell proliferation. On the other hand, either the membrane-associated or the actin/myosin-binding domains of anillin could not substitute for the corresponding ezrin domains in controlling cortical blebbing at the cell poles. Our results highlight specific designs of actin- or membrane-associated moieties of different actin-membrane associated proteins with limited exchangeability, which enables them to support diverse cortical activities on the shared actin-membrane interface during cytokinesis.
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Ghosh I, Singh RK, Mishra M, Kapoor S, Jana SS. Switching between blebbing and lamellipodia depends on the degree of non-muscle myosin II activity. J Cell Sci 2021; 134:jcs.248732. [PMID: 33298514 DOI: 10.1242/jcs.248732] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2020] [Accepted: 11/19/2020] [Indexed: 01/09/2023] Open
Abstract
Cells can adopt both mesenchymal and amoeboid modes of migration through membrane protrusive activities, namely formation of lamellipodia and blebbing. How the molecular players control the transition between lamellipodia and blebs is yet to be explored. Here, we show that addition of the ROCK inhibitor Y27632 or low doses of blebbistatin, an inhibitor of non-muscle myosin II (NMII) ATPase activity and filament partitioning, induces blebbing to lamellipodia conversion (BLC), whereas addition of low doses of ML7, an inhibitor of myosin light chain kinase (MLCK), induces lamellipodia to blebbing conversion (LBC) in human MDA-MB-231 cells. Similarly, siRNA-mediated knockdown of ROCK and MLCK induces BLC and LBC, respectively. Interestingly, both blebs and lamellipodia membrane protrusions are able to maintain the ratio of phosphorylated to unphosphorylated regulatory light chain at cortices when MLCK and ROCK, respectively, are inhibited either pharmacologically or genetically, suggesting that MLCK and ROCK activities are interlinked in BLC and LBC. Such BLCs and LBCs are also inducible in other cell lines, including MCF7 and MCF10A. These studies reveal that the relative activity of ROCK and MLCK, which controls both the ATPase activity and filament-forming property of NMII, is a determining factor in whether a cell exhibits blebbing or lamellipodia.
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Affiliation(s)
- Indranil Ghosh
- School of Biological Sciences, Indian Association for the Cultivation of Science, Kolkata 700032, India
| | - Raman K Singh
- School of Biological Sciences, Indian Association for the Cultivation of Science, Kolkata 700032, India.,Weizmann Institute of Science, Rehovot 7610001, Israel
| | - Manjari Mishra
- Department of Chemistry, Indian Institute of Technology - Bombay, Mumbai 400076, India
| | - Shobhna Kapoor
- Department of Chemistry, Indian Institute of Technology - Bombay, Mumbai 400076, India
| | - Siddhartha S Jana
- School of Biological Sciences, Indian Association for the Cultivation of Science, Kolkata 700032, India
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6
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Girstmair J, Telford MJ. Reinvestigating the early embryogenesis in the flatworm Maritigrella crozieri highlights the unique spiral cleavage program found in polyclad flatworms. EvoDevo 2019; 10:12. [PMID: 31285819 PMCID: PMC6588950 DOI: 10.1186/s13227-019-0126-5] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2019] [Accepted: 06/08/2019] [Indexed: 11/30/2022] Open
Abstract
BACKGROUND Spiral cleavage is a conserved, early developmental mode found in several phyla of Lophotrochozoans resulting in highly diverse adult body plans. While the cleavage pattern has clearly been broadly conserved, it has also undergone many modifications in various taxa. The precise mechanisms of how different adaptations have altered the ancestral spiral cleavage pattern are an important ongoing evolutionary question, and adequately answering this question requires obtaining a broad developmental knowledge of different spirally cleaving taxa. In flatworms (Platyhelminthes), the spiral cleavage program has been lost or severely modified in most taxa. Polyclad flatworms, however, have retained the pattern up to the 32-cell stage. Here we study early embryogenesis of the cotylean polyclad flatworm Maritigrella crozieri to investigate how closely this species follows the canonical spiral cleavage pattern and to discover any potential deviations from it. RESULTS Using live imaging recordings and 3D reconstructions of embryos, we give a detailed picture of the events that occur during spiral cleavage in M. crozieri. We suggest, contrary to previous observations, that the four-cell stage is a product of unequal cleavages. We show that that the formation of third and fourth micromere quartets is accompanied by strong blebbing events; blebbing also accompanies the formation of micromere 4d. We find an important deviation from the canonical pattern of cleavages with clear evidence that micromere 4d follows an atypical cleavage pattern, so far exclusively found in polyclad flatworms. CONCLUSIONS Our findings highlight that early development in M. crozieri deviates in several important aspects from the canonical spiral cleavage pattern. We suggest that some of our observations extend to polyclad flatworms in general as they have been described in both suborders of the Polycladida, the Cotylea and Acotylea.
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Affiliation(s)
- Johannes Girstmair
- Centre for Life’s Origins and Evolution, Department of Genetics, Evolution and Environment, University College London, London, WC1E 6BT UK
- Max Planck Institute of Molecular Cell Biology and Genetics, Pfotenhauerstraße 108, 01307 Dresden, Germany
| | - Maximilian J. Telford
- Centre for Life’s Origins and Evolution, Department of Genetics, Evolution and Environment, University College London, London, WC1E 6BT UK
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Chan JY, Ahmad Kayani AB, Md Ali MA, Kok CK, Ramdzan Buyong M, Hoe SLL, Marzuki M, Soo-Beng Khoo A, Sriram S, Ostrikov KK. Dielectrophoretic deformation of breast cancer cells for lab on a chip applications. Electrophoresis 2019; 40:2728-2735. [PMID: 31219180 DOI: 10.1002/elps.201800442] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2018] [Revised: 04/19/2019] [Accepted: 05/28/2019] [Indexed: 11/08/2022]
Abstract
This paper presents the development and experimental analysis of a curved microelectrode platform for the DEP deformation of breast cancer cells (MDA-MB-231). The platform is composed of arrays of curved DEP microelectrodes which are patterned onto a glass slide and samples containing MDA-MB-231 cells are pipetted onto the platform's surface. Finite element method is utilised to characterise the electric field gradient and DEP field. The performance of the system is assessed with MDA-MB-231 cells in a low conductivity 1% DMEM suspending medium. We applied sinusoidal wave AC potential at peak to peak voltages of 2, 5, and 10 Vpp at both 10 kHz and 50 MHz. We observed cell blebbing and cell shrinkage and analyzed the percentage of shrinkage of the cells. The experiments demonstrated higher percentage of cell shrinkage when cells are exposed to higher frequency and peak to peak voltage electric field.
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Affiliation(s)
- Jun Yuan Chan
- Center for Advanced Materials and Green Technology, Multimedia University, Melaka, Malaysia
| | - Aminuddin Bin Ahmad Kayani
- Center for Advanced Materials and Green Technology, Multimedia University, Melaka, Malaysia.,Functional Materials and Microsystems Research Group and the Micro Nano Research Facility, RMIT University, Melbourne, Australia
| | - Mohd Anuar Md Ali
- Institute of Microengineering and Nanoelectronics, Universiti Kebangsaan Malaysia, Bangi, Selangor, Malaysia
| | - Chee Kuang Kok
- Center for Advanced Materials and Green Technology, Multimedia University, Melaka, Malaysia
| | - Muhamad Ramdzan Buyong
- Institute of Microengineering and Nanoelectronics, Universiti Kebangsaan Malaysia, Bangi, Selangor, Malaysia
| | - Susan Ling Ling Hoe
- Molecular Pathology Unit, Cancer Research Centre, Institute for Medical Research, Kuala Lumpur, Malaysia
| | - Marini Marzuki
- Molecular Pathology Unit, Cancer Research Centre, Institute for Medical Research, Kuala Lumpur, Malaysia
| | - Alan Soo-Beng Khoo
- Molecular Pathology Unit, Cancer Research Centre, Institute for Medical Research, Kuala Lumpur, Malaysia.,Institute for Research, Development and Innovation, International Medical University, Kuala Lumpur, Malaysia.,Faculty of Engineering, Computing and Science, Swinburne University of Technology Sarawak Campus, Kuching, Sarawak, Malaysia
| | - Sharath Sriram
- Functional Materials and Microsystems Research Group and the Micro Nano Research Facility, RMIT University, Melbourne, Australia
| | - Kostya Ken Ostrikov
- School of Chemistry, Physics and Mechanical Engineering, Queensland University of Technology, Brisbane, Australia.,CSIRO-QUT Sustainable Processes and Devices Laboratory, Lindfield, New South Wales, Australia
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8
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Brito C, Cabanes D, Sarmento Mesquita F, Sousa S. Mechanisms protecting host cells against bacterial pore-forming toxins. Cell Mol Life Sci 2018; 76:1319-1339. [PMID: 30591958 PMCID: PMC6420883 DOI: 10.1007/s00018-018-2992-8] [Citation(s) in RCA: 85] [Impact Index Per Article: 14.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2018] [Revised: 12/06/2018] [Accepted: 12/10/2018] [Indexed: 12/19/2022]
Abstract
Pore-forming toxins (PFTs) are key virulence determinants produced and secreted by a variety of human bacterial pathogens. They disrupt the plasma membrane (PM) by generating stable protein pores, which allow uncontrolled exchanges between the extracellular and intracellular milieus, dramatically disturbing cellular homeostasis. In recent years, many advances were made regarding the characterization of conserved repair mechanisms that allow eukaryotic cells to recover from mechanical disruption of the PM membrane. However, the specificities of the cell recovery pathways that protect host cells against PFT-induced damage remain remarkably elusive. During bacterial infections, the coordinated action of such cell recovery processes defines the outcome of infected cells and is, thus, critical for our understanding of bacterial pathogenesis. Here, we review the cellular pathways reported to be involved in the response to bacterial PFTs and discuss their impact in single-cell recovery and infection.
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Affiliation(s)
- Cláudia Brito
- i3S-Instituto de Investigação e Inovação em Saúde, IBMC, Universidade do Porto, Rua Alfredo Allen, 208, 4200-135, Porto, Portugal
- Programa Doutoral em Biologia Molecular e Celular (MCbiology), Instituto de Ciências Biomédicas Abel Salazar, Universidade do Porto, Rua Jorge de Viterbo Ferreira 228, 4050-313, Porto, Portugal
| | - Didier Cabanes
- i3S-Instituto de Investigação e Inovação em Saúde, IBMC, Universidade do Porto, Rua Alfredo Allen, 208, 4200-135, Porto, Portugal
| | - Francisco Sarmento Mesquita
- i3S-Instituto de Investigação e Inovação em Saúde, IBMC, Universidade do Porto, Rua Alfredo Allen, 208, 4200-135, Porto, Portugal.
- Global Health Institute, School of Life Science, Ecole Polytechnique Fédérale de Lausanne, Lausanne, Switzerland.
| | - Sandra Sousa
- i3S-Instituto de Investigação e Inovação em Saúde, IBMC, Universidade do Porto, Rua Alfredo Allen, 208, 4200-135, Porto, Portugal.
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Weng NJH, Cheung C, Talbot P. Dynamic blebbing: A bottleneck to human embryonic stem cell culture that can be overcome by Laminin-Integrin signaling. Stem Cell Res 2018; 33:233-246. [PMID: 30458343 PMCID: PMC6414319 DOI: 10.1016/j.scr.2018.10.022] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/17/2016] [Revised: 10/25/2018] [Accepted: 10/31/2018] [Indexed: 12/11/2022] Open
Abstract
This study characterizes dynamic and apoptotic blebbing in human embryonic stem cells (hESC), identifies dynamic blebbing as a bottleneck to successful cell attachment during passaging, and demonstrates that dynamic blebbing can be rapidly stopped by plating cells on recombinant human laminin. In freshly plated hESC, dynamic and apoptotic blebbing differed in time of occurrence, bleb retraction rate, mitochondrial membrane potential, and caspase 3&7 activation. While dynamic blebbing can be controlled with drugs that inhibit myosin II, these methods have off-target effects and are not suitable for clinical applications. Recombinant human laminin-521 or addition of laminin-111 to Matrigel provided a safe method to drastically decrease dynamic blebbing and improve cell attachment with proteins normally found in the inner cell mass. Inhibition of focal adhesion kinase, which is activated by binding of integrins to laminin, prolonged dynamic blebbing and inhibited attachment. These data show that hESC bind rapidly to laminins through an integrin, which activates focal adhesion kinase that in turn downregulates dynamic blebbing. Laminins enabled hESC to rapidly attach during passaging, improved plating efficiency, enabled passaging of single pluripotent stem cells, and avoided use of inhibitors that have non-specific off-target effects. These data provide a strategy for improving hESC culture using biologically safe recombinant human proteins.
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Affiliation(s)
- Nikki Jo-Hao Weng
- Department of Molecular, Cell and Systems Biology, University of California, Riverside, CA 92521, United States; Cell Molecular and Developmental Biology Graduate Program, University of California, Riverside, CA 92521, United States
| | - Cindy Cheung
- Department of Molecular, Cell and Systems Biology, University of California, Riverside, CA 92521, United States
| | - Prue Talbot
- Department of Molecular, Cell and Systems Biology, University of California, Riverside, CA 92521, United States; Cell Molecular and Developmental Biology Graduate Program, University of California, Riverside, CA 92521, United States.
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10
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Tixeira R, Poon IKH. Disassembly of dying cells in diverse organisms. Cell Mol Life Sci 2019; 76:245-57. [PMID: 30317529 DOI: 10.1007/s00018-018-2932-7] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2018] [Revised: 09/25/2018] [Accepted: 10/01/2018] [Indexed: 01/09/2023]
Abstract
Programmed cell death (PCD) is a conserved phenomenon in multicellular organisms required to maintain homeostasis. Among the regulated cell death pathways, apoptosis is a well-described form of PCD in mammalian cells. One of the characteristic features of apoptosis is the change in cellular morphology, often leading to the fragmentation of the cell into smaller membrane-bound vesicles through a process called apoptotic cell disassembly. Interestingly, some of these morphological changes and cell disassembly are also noted in cells of other organisms including plants, fungi and protists while undergoing 'apoptosis-like PCD'. This review will describe morphologic features leading to apoptotic cell disassembly, as well as its regulation and function in mammalian cells. The occurrence of cell disassembly during cell death in other organisms namely zebrafish, fly and worm, as well as in other eukaryotic cells will also be discussed.
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Abstract
Many researchers use the social amoeba Dictyostelium discoideum as a model organism to study various aspects of the eukaryotic cell chemotaxis. Traditionally, Dictyostelium chemotaxis is considered to be driven mainly by branched F-actin polymerization. However, recently it has become evident that Dictyostelium, as well as many other eukaryotic cells, can also employ intracellular hydrostatic pressure to generate force for migration. This process results in the projection of hemispherical plasma membrane protrusions, called blebs, that can be controlled by chemotactic signaling.Here we describe two methods to study chemotactic blebbing in Dictyostelium cells and to analyze the intensity of the blebbing response in various strains and under different conditions. The first of these methods-the cyclic-AMP shock assay-allows one to quantify the global blebbing response of cells to a uniform chemoattractant stimulation. The second one-the under-agarose migration assay-induces directional blebbing in cells moving in a gradient of chemoattractant. In this assay, the cells can be switched from a predominantly F-actin-driven mode of motility to a bleb-driven chemotaxis, allowing one to compare the efficiency of both modes and explore the molecular machinery controlling chemotactic blebbing.
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Affiliation(s)
- Evgeny Zatulovskiy
- Department of Biology, Stanford University, 337 Campus Drive, Stanford, CA, 94305, USA.
| | - Robert R Kay
- MRC Laboratory of Molecular Biology, Francis Crick Avenue, Cambridge Biomedical Campus, Cambridge, CB2 0QH, UK
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12
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Rana PS, Mudrak NJ, Lopez R, Lynn M, Kershner L, Model MA. Phase separation in necrotic cells. Biochem Biophys Res Commun 2017; 492:300-303. [PMID: 28859980 DOI: 10.1016/j.bbrc.2017.08.123] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2017] [Accepted: 08/28/2017] [Indexed: 12/25/2022]
Abstract
Necrotic cells are known to develop characteristic membrane blebs. We measured protein concentration within necrotic blebs and found that it can be reduced by as much as twenty-fold compared to the main cell body (CB). These results raise two questions: 1. Why do proteins vacate the bleb? 2. How can osmotic equilibrium be maintained between the bleb and CB? Our photobleaching and ultracentrifugation experiments indicate extensive protein aggregation. We hypothesize that protein aggregation within the CB shifts the chemical equilibrium and draws proteins out of the bleb; at the same time, aggregation reduces the effective molar concentration of protein in the CB, so that osmotic equilibrium between high-protein CB and low-protein necrotic blebs becomes possible.
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Affiliation(s)
- Priyanka S Rana
- Department of Biological Sciences, Kent State University, Kent, OH, USA
| | - Nathan J Mudrak
- Department of Biological Sciences, Kent State University, Kent, OH, USA
| | | | - Matthew Lynn
- Department of Biological Sciences, Kent State University, Kent, OH, USA
| | - Leah Kershner
- Department of Biological Sciences, Kent State University, Kent, OH, USA
| | - Michael A Model
- Department of Biological Sciences, Kent State University, Kent, OH, USA.
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13
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Qudrat A, Wong J, Truong K. Engineering mammalian cells to seek senescence-associated secretory phenotypes. J Cell Sci 2017; 130:3116-3123. [PMID: 28754685 DOI: 10.1242/jcs.206979] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2017] [Accepted: 07/25/2017] [Indexed: 12/14/2022] Open
Abstract
Since the removal of senescent cells in model organisms has been linked to rejuvenation and increased lifespan, senotherapies have emerged to target senescent cells for death. In particular, interleukin-6 (IL6) is a prominent senescence-associated secretory phenotype (SASP) and, thus, seeking IL6 could potentially localize engineered cells to senescent cells for therapeutic intervention. Here, we engineered a chimeric IL6 receptor (IL6Rchi) that generates a Ca2+ signal in response to IL6 stimulation. When IL6Rchi was co-expressed with an engineered Ca2+-activated RhoA (CaRQ), it enabled directed migration to IL6 in cells that have no such natural ability. Next, the removal of target cells was accomplished by the mechanism of membrane fusion and subsequent death. This work represents a first step towards engineering a cell to target senescent cells that secrete high levels of IL6. For increased specificity to senescent cells, it will likely be necessary for an engineered cell to recognize multiple SASPs simultaneously.
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Affiliation(s)
- Anam Qudrat
- Institute of Biomaterials and Biomedical Engineering, University of Toronto, 164 College Street, Toronto, Ontario, M5S 3G9, Canada
| | - Janice Wong
- Institute of Biomaterials and Biomedical Engineering, University of Toronto, 164 College Street, Toronto, Ontario, M5S 3G9, Canada
| | - Kevin Truong
- Institute of Biomaterials and Biomedical Engineering, University of Toronto, 164 College Street, Toronto, Ontario, M5S 3G9, Canada .,Edward S. Rogers, Sr. Department of Electrical and Computer Engineering, University of Toronto, 10 King's College Circle, Toronto, Ontario, M5S 3G4, Canada
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14
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Weng NJH, Talbot P. The P2X7 receptor is an upstream regulator of dynamic blebbing and a pluripotency marker in human embryonic stem cells. Stem Cell Res 2017; 23:39-49. [PMID: 28672157 DOI: 10.1016/j.scr.2017.06.007] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/04/2017] [Revised: 05/19/2017] [Accepted: 06/13/2017] [Indexed: 11/18/2022] Open
Abstract
New methods are needed to reduce dynamic blebbing which inhibits cell attachment and survival during passaging of pluripotent stem cells. We tested the hypothesis that activation of the P2X7 receptor by extracellular ATP during passaging initiates dynamic blebbing. The P2X7 receptor was present in human embryonic stem cells (hESC), but not in differentiating cells. Extracellular ATP concentrations were 14× higher in medium during passaging. Addition of ATP to culture medium prolonged dynamic blebbing and inhibited attachment. Inhibition of P2X7 by specific drugs or by siRNA significantly reduced dynamic blebbing and improved cell attachment. When cells were incubated in calcium chelators (EGTA or BAPTA), blebbing decreased and attachment improved. Calcium influx was observed using Fura-4 when ATP was added to culture medium and inhibited in the presence of the P2X7 inhibitor. Over-expressing activated Rac in hESC reduced blebbing and promoted cell attachment, while a Rac inhibitor prolonged blebbing and reduced attachment. These data identify a pathway involving P2X7 that initiates and prolongs dynamic blebbing during hESC passaging. This pathway provides new insight into factors that increase dynamic blebbing and identifies new targets, such as P2X7, that can be used to improve the culture of cells with therapeutic potential.
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Affiliation(s)
- Nikki Jo-Hao Weng
- Department of Cell Biology and Neuroscience, University of California, Riverside, CA 92521, USA; Cell, Molecular, and Developmental Biology Graduate Program, University of California, Riverside, CA 92521, USA
| | - Prue Talbot
- Department of Cell Biology and Neuroscience, University of California, Riverside, CA 92521, USA; Cell, Molecular, and Developmental Biology Graduate Program, University of California, Riverside, CA 92521, USA.
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15
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Koifman N, Biran I, Aharon A, Brenner B, Talmon Y. A direct-imaging cryo-EM study of shedding extracellular vesicles from leukemic monocytes. J Struct Biol 2017; 198:177-185. [PMID: 28254382 DOI: 10.1016/j.jsb.2017.02.004] [Citation(s) in RCA: 37] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2016] [Revised: 02/09/2017] [Accepted: 02/14/2017] [Indexed: 02/08/2023]
Abstract
The human leukemia monocytic cell line (THP-1) is known to shed extracellular vesicles (EVs) under various stimulations. We studied the effects of two types of common stimulation types, lipopolysaccharide (LPS) and starvation conditions by high resolution cryogenic electron microscopy, namely, cryo-SEM and cryo-TEM. Cryo-SEM data of cells undergoing EV blebbing and shedding is presented here for the first time. The high-resolution images show good agreement with models describing the membrane processes of shedding. Cells that underwent a 48-h starvation treatment exhibited differing morphological features, including shrunken nucleus and elongated membrane protrusions. LPS treated cells, however, showed extensive blebbing originating from the cell membrane, in good agreement with the sizes of EVs imaged by cryo-TEM. EVs isolated from both types of stimulations were measured by nanoparticle tracking analysis (NanoSight), by which LPS-EVs samples exhibited higher concentration and smaller mean diameter, as compared to starvation-EVs. Our results suggest a difference in the effects of the two stimulation types on the shedding process and possibly on the type of EVs shed. Our unique methodologies provide an important and innovative outlook of the shedding process and on its products, paving the way to further discoveries in this developing field of research, in which much is still unknown.
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Affiliation(s)
- Na'ama Koifman
- Department of Chemical Engineering and the Russell Berrie Nanotechnology Institute, Technion-Israel Institute of Technology, Haifa 3200003, Israel
| | - Idan Biran
- Department of Chemical Engineering and the Russell Berrie Nanotechnology Institute, Technion-Israel Institute of Technology, Haifa 3200003, Israel
| | - Anat Aharon
- The Bruce Rappaport Faculty of Medicine, Technion-Israel Institute of Technology, Haifa 3525433, Israel; Department of Hematology and Bone Marrow Transplantation, Rambam Health Care Campus, Haifa 3109601, Israel
| | - Benjamin Brenner
- The Bruce Rappaport Faculty of Medicine, Technion-Israel Institute of Technology, Haifa 3525433, Israel; Department of Hematology and Bone Marrow Transplantation, Rambam Health Care Campus, Haifa 3109601, Israel
| | - Yeshayahu Talmon
- Department of Chemical Engineering and the Russell Berrie Nanotechnology Institute, Technion-Israel Institute of Technology, Haifa 3200003, Israel.
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16
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Prajitha V, Thoppil JE. Cytotoxic and apoptotic activities of extract of Amaranthus spinosus L. in Allium cepa and human erythrocytes. Cytotechnology 2017; 69:123-133. [PMID: 27896557 PMCID: PMC5264628 DOI: 10.1007/s10616-016-0044-5] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2015] [Accepted: 11/16/2016] [Indexed: 10/20/2022] Open
Abstract
The present study examined the apoptosis inducing effects of Amaranthus spinosus L. aqueous extract in Allium cepa root meristematic cells and human erythrocytes. Cytogenetic assay revealed many apoptosis inducing cytogenetic aberrations viz., cytoplasmic breakage, cytoplasmic disintegration, cytoplasmic shrinkage, receding of cytoplasm, cytoplasmic vacuolation, enucleated cell, ghost cell, nuclear vacuolation, nuclear fragmentation and nuclear disintegration. A remarkable modification of red blood cell surface morphology was observed in the result of RBC assay. The treated RBCs show membrane blebbing and shrinkage, features typical for apoptosis in nucleated cells. Significant induction of cell death was observed in treated Allium root tip cells after Evans blue staining, disclosing the membrane damage potential of the plant extract. TTC assay results in reduced mitochondrial/metabolic activity in Allium root tip cells after treatment, designating the adverse effect of plant extract on mitochondrial respiratory chain. These results confirm the apoptosis inducing potential of A. spinosus extract. Confirming the present results by further in vitro studies, it can be effectively targeted against cell proliferation during cancer treatment by inducing apoptosis. Thus from the present investigation it can be concluded that the aqueous extract of A. spinosus exhibited apoptosis induction and cytotoxic activities.
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Affiliation(s)
- V Prajitha
- Cell and Molecular Biology Division, Department of Botany, University of Calicut, Malappuram, Kerala, 673635, India.
| | - J E Thoppil
- Cell and Molecular Biology Division, Department of Botany, University of Calicut, Malappuram, Kerala, 673635, India
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17
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Abstract
Cell migration is necessary for several developmental processes in multicellular organisms. Furthermore, many physiological processes such as wound healing and immunological events in adult animals are dependent on cell migration. Consequently, defects in cell migration are linked to various diseases including immunological disorders as well as cancer progression and metastasis formation. Cell migration is driven by specific protrusive and contractile actin filament structures, but the types and relative contributions of these actin filament arrays vary depending on the cell type and the environment of the cell. In this chapter, we introduce the most important actin filament structures that contribute to mesenchymal and amoeboid cell migration modes and discuss the mechanisms by which the assembly and turnover of these structures are controlled by various actin-binding proteins.
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Affiliation(s)
- Jaakko Lehtimäki
- Institute of Biotechnology, University of Helsinki, 56, 00014, Helsinki, Finland
| | - Markku Hakala
- Institute of Biotechnology, University of Helsinki, 56, 00014, Helsinki, Finland
| | - Pekka Lappalainen
- Institute of Biotechnology, University of Helsinki, 56, 00014, Helsinki, Finland.
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18
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Babiychuk EB, Draeger A. Defying death: Cellular survival strategies following plasmalemmal injury by bacterial toxins. Semin Cell Dev Biol 2015; 45:39-47. [PMID: 26481974 DOI: 10.1016/j.semcdb.2015.10.016] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2015] [Accepted: 10/12/2015] [Indexed: 10/22/2022]
Abstract
The perforation of the plasmalemma by pore-forming toxins causes an influx of Ca(2+) and an efflux of cytoplasmic constituents. In order to ensure survival, the cell needs to identify, plug and remove lesions from its membrane. Quarantined by membrane folds and isolated by membrane fusion, the pores are removed from the plasmalemma and expelled into the extracellular space. Outward vesiculation and microparticle shedding seem to be the strategies of choice to eliminate toxin-perforated membrane regions from the plasmalemma of host cells. Depending on the cell type and the nature of injury, the membrane lesion can also be taken up by endocytosis and degraded internally. Host cells make excellent use of an initial, moderate rise in intracellular [Ca(2+)], which triggers containment of the toxin-inflicted damage and resealing of the damaged plasmalemma. Additional Ca(2+)-dependent defensive cellular actions range from the release of effector molecules in order to warn neighbouring cells, to the activation of caspases for the initiation of apoptosis in order to eliminate heavily damaged, dysregulated cells. Injury to the plasmalemma by bacterial toxins can be prevented by the early sequestration of bacterial toxins. Artificial liposomes can act as a decoy system preferentially binding and neutralizing bacterial toxins.
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19
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Roth H, Samereier M, Trommler G, Noegel AA, Schleicher M, Müller-Taubenberger A. Balanced cortical stiffness is important for efficient migration of Dictyostelium cells in confined environments. Biochem Biophys Res Commun 2015; 467:730-5. [PMID: 26482849 DOI: 10.1016/j.bbrc.2015.10.073] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2015] [Accepted: 10/14/2015] [Indexed: 10/22/2022]
Abstract
Dictyostelium discoideum cells resemble in many aspects human leukocytes and serve as a model to study actin cytoskeleton dynamics and cell migration of highly motile cells. Dictyostelium cells deficient in the actin-binding protein filamin (ddFLN) showed a surprisingly subtle change in phenotype with no or only minor effects in single cell motility. These findings were in contrast to the strong actin-crosslinking activities measured for filamin in vitro. In the present study, we set out to revisit the role of ddFLN in cell migration. For this purpose, we examined migration of wild-type, ddFLN-null and ddFLN-overexpressing cells under different conditions. In addition to cyclic-AMP chemotaxis assays using micropipettes, we explored cell migration under more confined conditions: an under-agarose 2D assay and a 3D assay employing a collagen matrix that was adapted from assays for leukocytes. Using 3D migration conditions, cells deficient in ddFLN displayed only a minor impairment of motility, similar to the results obtained for migration in 2D. However, cells overexpressing ddFLN showed a remarkable decrease in the speed of migration in particular in 3D environments. We suggest that these results are in line with an increased stiffening of the cortex due to the crosslinking activity of overexpressed ddFLN. Our conclusion is that the absolute level of ddFLN is critical for efficient migration. Furthermore, our results show that under conditions of increased mechanical stress, Dictyostelium cells, like leukocytes, switch to a bleb-based mode of movement.
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Affiliation(s)
- Heike Roth
- Department of Cell Biology (Anatomy III), Biomedical Center, Ludwig Maximilian University of Munich, 82152, Planegg-Martinsried, Germany
| | - Matthias Samereier
- Department of Cell Biology (Anatomy III), Biomedical Center, Ludwig Maximilian University of Munich, 82152, Planegg-Martinsried, Germany
| | - Gudrun Trommler
- Department of Cell Biology (Anatomy III), Biomedical Center, Ludwig Maximilian University of Munich, 82152, Planegg-Martinsried, Germany
| | - Angelika A Noegel
- Institute for Biochemistry I, Medical Faculty, University of Cologne, 50931, Cologne, Germany
| | - Michael Schleicher
- Department of Cell Biology (Anatomy III), Biomedical Center, Ludwig Maximilian University of Munich, 82152, Planegg-Martinsried, Germany
| | - Annette Müller-Taubenberger
- Department of Cell Biology (Anatomy III), Biomedical Center, Ludwig Maximilian University of Munich, 82152, Planegg-Martinsried, Germany.
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20
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Woolley TE, Gaffney EA, Oliver JM, Waters SL, Baker RE, Goriely A. Global contraction or local growth, bleb shape depends on more than just cell structure. J Theor Biol 2015; 380:83-97. [PMID: 25934350 DOI: 10.1016/j.jtbi.2015.04.023] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2014] [Revised: 01/20/2015] [Accepted: 04/18/2015] [Indexed: 12/20/2022]
Abstract
When the plasma membrane of a cell locally delaminates from its actin cortex the membrane is pushed outwards due to the cell׳s internal fluid pressure. The resulting spherical protrusion is known as a bleb. A cell׳s ability to function correctly is highly dependent on the production of such protrusions with the correct size and shape. Here, we investigate the nucleation of large blebs from small, local neck regions. A mathematical model of a cell׳s membrane, cortex and interconnecting adhesions demonstrates that these three components are unable to capture experimentally observed bleb shapes without the addition of further assumptions. We have identified that combinations of global cortex contraction and localised membrane growth are the most promising methods for generating prototypical blebs. Currently, neither proposed mechanism has been fully tested experimentally and, thus, we propose experiments that will distinguish between the two methods of bleb production.
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21
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Draeger A, Schoenauer R, Atanassoff AP, Wolfmeier H, Babiychuk EB. Dealing with damage: plasma membrane repair mechanisms. Biochimie 2014; 107 Pt A:66-72. [PMID: 25183513 DOI: 10.1016/j.biochi.2014.08.008] [Citation(s) in RCA: 57] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2014] [Accepted: 08/15/2014] [Indexed: 12/22/2022]
Abstract
Eukaryotic cells have developed repair mechanisms, which allow them to reseal their membrane in order to prevent the efflux of cytoplasmic constituents and the uncontrolled influx of calcium. After injury, the Ca(2+)-concentration gradient fulfils a dual function: it provides guidance cues for the repair machinery and directly activates the molecules, which have a repair function. Depending on the nature of injury, the morphology of the cell and the severity of injury, the membrane resealing can be effected by lysosomal exocytosis, microvesicle shedding or a combination of both. Likewise, exocytosis is often followed by the endocytic uptake of lesions. Additionally, since plasmalemmal resealing must be attempted, even after extensive injury in order to prevent cell lysis, the restoration of membrane integrity can be achieved by ceramide-driven invagination of the lipid bilayer, during which the cell is prepared for apoptotic disposal. Plasmalemmal injury can be contained by a surfeit of plasma membrane, which serves as a trap for toxic substances: either passively by an abundance of cellular protrusions, or actively by membrane blebbing.
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Affiliation(s)
- Annette Draeger
- Department of Cell Biology, Institute of Anatomy, University of Bern, Baltzerstr. 2, 3012 Bern, Switzerland.
| | - Roman Schoenauer
- Department of Cell Biology, Institute of Anatomy, University of Bern, Baltzerstr. 2, 3012 Bern, Switzerland
| | - Alexander P Atanassoff
- Department of Cell Biology, Institute of Anatomy, University of Bern, Baltzerstr. 2, 3012 Bern, Switzerland
| | - Heidi Wolfmeier
- Department of Cell Biology, Institute of Anatomy, University of Bern, Baltzerstr. 2, 3012 Bern, Switzerland
| | - Eduard B Babiychuk
- Department of Cell Biology, Institute of Anatomy, University of Bern, Baltzerstr. 2, 3012 Bern, Switzerland
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22
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Horiguchi A, Yazaki K, Aoyagi M, Ohnuki Y, Kurosawa H. Effective Rho-associated protein kinase inhibitor treatment to dissociate human iPS cells for suspension culture to form embryoid body-like cell aggregates. J Biosci Bioeng 2014; 118:588-92. [PMID: 24856590 DOI: 10.1016/j.jbiosc.2014.04.008] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2014] [Revised: 04/08/2014] [Accepted: 04/11/2014] [Indexed: 12/26/2022]
Abstract
Treatment conditions using Y-27632 in the preparation of cell suspension of dissociated human pluripotent stem cells (hiPSCs) were investigated in the context of embryoid body (EB)-like cell aggregates. The effectiveness of a pretreatment with Y-27632 before cell dissociation and that of a Y-27632 treatment during cell dissociation were investigated from the viewpoint of simplicity and robustness. The duration of Y-27632 treatment in the preparation process affected the circularity and agglomeration of dissociated hiPSCs. A single application of pretreatment failed to prevent the onset of blebbing. However, a pretreatment promoted the agglomeration of dissociated hiPSCs when combined with the addition of Y-27632 to cell suspension. Our results indicate that pretreatment enhances the agglomeration potential of dissociated hiPSCs. When cell dissociation was performed in the presence of Y-27632, dissociated hiPSCs possessed the highest circularity and significant agglomerating property. It was shown that treatment with Y-27632 during cell dissociation is a simple and robust method to prepare dissociated hiPSCs for suspension culture to form EB-like cell aggregates.
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23
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Schoenauer R, Atanassoff AP, Wolfmeier H, Pelegrin P, Babiychuk EB, Draeger A. P2X7 receptors mediate resistance to toxin-induced cell lysis. Biochim Biophys Acta 2014; 1843:915-22. [PMID: 24487066 DOI: 10.1016/j.bbamcr.2014.01.024] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Received: 09/16/2013] [Revised: 01/17/2014] [Accepted: 01/23/2014] [Indexed: 02/02/2023]
Abstract
In the majority of cells, the integrity of the plasmalemma is recurrently compromised by mechanical or chemical stress. Serum complement or bacterial pore-forming toxins can perforate the plasma membrane provoking uncontrolled Ca(2+) influx, loss of cytoplasmic constituents and cell lysis. Plasmalemmal blebbing has previously been shown to protect cells against bacterial pore-forming toxins. The activation of the P2X7 receptor (P2X7R), an ATP-gated trimeric membrane cation channel, triggers Ca(2+) influx and induces blebbing. We have investigated the role of the P2X7R as a regulator of plasmalemmal protection after toxin-induced membrane perforation caused by bacterial streptolysin O (SLO). Our results show that the expression and activation of the P2X7R furnishes cells with an increased chance of surviving attacks by SLO. This protective effect can be demonstrated not only in human embryonic kidney 293 (HEK) cells transfected with the P2X7R, but also in human mast cells (HMC-1), which express the receptor endogenously. In addition, this effect is abolished by treatment with blebbistatin or A-438079, a selective P2X7R antagonist. Thus blebbing, which is elicited by the ATP-mediated, paracrine activation of the P2X7R, is part of a cellular non-immune defense mechanism. It pre-empts plasmalemmal damage and promotes cellular survival. This mechanism is of considerable importance for cells of the immune system which carry the P2X7R and which are specifically exposed to toxin attacks.
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Affiliation(s)
| | | | | | - Pablo Pelegrin
- Inflammation and Experimental Surgery Research, University Hospital Virgen de la Arrixaca - FFIS, Murcia, Spain
| | | | - Annette Draeger
- Institute of Anatomy, University of Bern, Bern, Switzerland.
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