201
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Gambardella L, Vermeren S. Molecular players in neutrophil chemotaxis-focus on PI3K and small GTPases. J Leukoc Biol 2013; 94:603-12. [DOI: 10.1189/jlb.1112564] [Citation(s) in RCA: 60] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023] Open
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202
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Stockley JA, Walton GM, Lord JM, Sapey E. Aberrant neutrophil functions in stable chronic obstructive pulmonary disease: the neutrophil as an immunotherapeutic target. Int Immunopharmacol 2013; 17:1211-7. [PMID: 23994347 DOI: 10.1016/j.intimp.2013.05.035] [Citation(s) in RCA: 47] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2012] [Accepted: 05/31/2013] [Indexed: 01/06/2023]
Abstract
Chronic obstructive pulmonary disease (COPD) is a common, progressive and debilitating chronic inflammatory condition affecting the lungs, with significant systemic manifestations and co-morbidities. Smoking cigarettes is the main risk factor, but only a fifth of smokers have clinically significant airflow obstruction and the inflammation persists after smoking cessation. This suggests that smoking (and exposure to other inhaled toxins) may be necessary but not sufficient to cause COPD. Neutrophils are believed central to COPD and their accumulation and degranulation are associated with tissue damage, increased inflammation and disordered tissue repair. It was assumed that neutrophil activity and function were appropriate in COPD, responding to the presence of high levels of inflammation in the lung. However more recent studies of neutrophil function (including migration, reactive oxygen species generation, degranulation, phagocytosis and extracellular trap (NET) production) suggest that there is a general impairment in COPD neutrophil responses that predispose towards increased inflammation and reduced bacterial clearance. This may be amenable to correction and manipulating neutrophil intracellular pathways (such as phosphoinositide-3-kinase signalling) appears to restore some key COPD neutrophil responses. Targeting neutrophil intra-cellular signalling may provide a means to normalise neutrophil behaviour in COPD. This could lead to improvements in disease outcomes by reducing extraneous inflammatory burden. However further studies are needed to determine if these findings are relevant in vivo and whether this would impact positively upon health and disease.
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Affiliation(s)
- James A Stockley
- Centre for Translational Inflammation Research, University of Birmingham, Edgbaston, Birmingham B15 2TT, United Kingdom
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203
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Kamakura S, Nomura M, Hayase J, Iwakiri Y, Nishikimi A, Takayanagi R, Fukui Y, Sumimoto H. The cell polarity protein mInsc regulates neutrophil chemotaxis via a noncanonical G protein signaling pathway. Dev Cell 2013; 26:292-302. [PMID: 23891662 DOI: 10.1016/j.devcel.2013.06.008] [Citation(s) in RCA: 57] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2013] [Revised: 05/07/2013] [Accepted: 06/07/2013] [Indexed: 12/15/2022]
Abstract
Successful chemotaxis requires not only increased motility but also sustained directionality. Here, we show that, during neutrophil chemotaxis via receptors coupled with the Gi family of heterotrimeric G proteins, directional movement is regulated by mInsc, a mammalian protein distantly related to the Drosophila polarity-organizer Inscuteable. The GDP-bound, Gβγ-free Gαi subunit accumulates at the front of chemotaxing neutrophils to recruit mInsc-complexed with the Par3-aPKC evolutionarily conserved polarity complex-via LGN/AGS3 that simultaneously binds to Gαi-GDP and mInsc. Both mInsc-deficient and aPKC-blocked neutrophils exhibit a normal motile activity but migrate in an undirected manner. mInsc deficiency prevents neutrophils from efficiently stabilizing pseudopods at the leading edge; the stability is restored by wild-type mInsc, but not by a mutant protein defective in binding to LGN/AGS3. Thus, mInsc controls directional migration via noncanonical G protein signaling, in which Gβγ-free Gαi-GDP, a product from Gαi-GTP released after receptor activation, plays a central role.
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Affiliation(s)
- Sachiko Kamakura
- Department of Biochemistry, Kyushu University Graduate School of Medical Sciences, Fukuoka 812-8582, Japan
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204
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Basu S, Sachidanandan C. Zebrafish: a multifaceted tool for chemical biologists. Chem Rev 2013; 113:7952-80. [PMID: 23819893 DOI: 10.1021/cr4000013] [Citation(s) in RCA: 48] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Affiliation(s)
- Sandeep Basu
- Council of Scientific and Industrial Research-Institute of Genomics & Integrative Biology (CSIR-IGIB) , South Campus, New Delhi 110025, India
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205
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Lam PY, Huttenlocher A. Interstitial leukocyte migration in vivo. Curr Opin Cell Biol 2013; 25:650-8. [PMID: 23797028 DOI: 10.1016/j.ceb.2013.05.007] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2013] [Revised: 05/12/2013] [Accepted: 05/31/2013] [Indexed: 01/06/2023]
Abstract
Rapid leukocyte motility is essential for immunity and host defense. There has been progress in understanding the molecular signals that regulate leukocyte motility both in vitro and in vivo. However, a gap remains in understanding how complex signals are prioritized to result in directed migration, which is critical for both adaptive and innate immune function. Here we focus on interstitial migration and how external cues are translated into intracellular signaling pathways that regulate leukocyte polarity, directional sensing and motility in three-dimensional spaces.
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Affiliation(s)
- Pui-ying Lam
- Program in Cellular and Molecular Biology, University of Wisconsin-Madison, Madison, WI 53706, USA
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206
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Thevathasan JV, Tan E, Zheng H, Lin YC, Li Y, Inoue T, Fivaz M. The small GTPase HRas shapes local PI3K signals through positive feedback and regulates persistent membrane extension in migrating fibroblasts. Mol Biol Cell 2013; 24:2228-37. [PMID: 23676667 PMCID: PMC3708728 DOI: 10.1091/mbc.e12-12-0905] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022] Open
Abstract
An inducible activation approach is used to interrogate the positive feedback circuit underlying self-amplification of PI3K signals in fibroblasts. The results show that local positive feedback between PI3K and HRas drives asymmetric membrane extension and cell migration. Self-amplification of phosphoinositide 3-kinase (PI3K) signaling is believed to regulate asymmetric membrane extension and cell migration, but the molecular organization of the underlying feedback circuit is elusive. Here we use an inducible approach to synthetically activate PI3K and interrogate the feedback circuitry governing self-enhancement of 3′-phosphoinositide (3-PI) signals in NIH3T3 fibroblasts. Synthetic activation of PI3K initially leads to uniform production of 3-PIs at the plasma membrane, followed by the appearance of asymmetric and highly amplified 3-PI signals. A detailed spatiotemporal analysis shows that local self-amplifying 3-PI signals drive rapid membrane extension with remarkable directional persistence and initiate a robust migratory response. This positive feedback loop is critically dependent on the small GTPase HRas. Silencing of HRas abrogates local amplification of 3-PI signals upon synthetic PI3K activation and results in short-lived protrusion events that do not support cell migration. Finally, our data indicate that this feedback circuit is likely to operate during platelet-derived growth factor–induced random cell migration. We conclude that positive feedback between PI3K and HRas is essential for fibroblasts to spontaneously self-organize and generate a productive migratory response in the absence of spatial cues.
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Affiliation(s)
- Jervis Vermal Thevathasan
- Program in Neuroscience and Neurobehavioral Disorders, Duke-NUS Graduate Medical School, Singapore 169857
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207
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Abstract
In the last five years, the zebrafish (Danio rerio) has rapidly gained popularity as a model system for studying leukocyte migration and trafficking in vivo. The optical clarity of zebrafish embryos, as well as the potential for genetic manipulation and the development of tools for live imaging, have provided new insight into how leukocytes migrate in response to directional cues in live animals. This Commentary discusses recent progress in our understanding of how leukocytes migrate in vivo, including the role of intracellular signaling through phosphatidylinositol 3-kinase (PI3K) in both random and directed migration. The importance of leukocyte reverse migration in the resolution of inflammation will also be discussed. Finally, we will highlight how zebrafish models have helped to provide new insight into leukocyte migration and the way in which migration is altered in disease.
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Affiliation(s)
- Qing Deng
- Department of Medical Microbiology and Immunology, University of Wisconsin-Madison, Madison, WI 53706, USA
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208
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Bischel LL, Mader BR, Green JM, Huttenlocher A, Beebe DJ. Zebrafish Entrapment By Restriction Array (ZEBRA) device: a low-cost, agarose-free zebrafish mounting technique for automated imaging. LAB ON A CHIP 2013; 13:1732-6. [PMID: 23503983 PMCID: PMC4446983 DOI: 10.1039/c3lc50099c] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/06/2023]
Abstract
The zebrafish has emerged as a useful model system for a variety of studies, including the investigation of inflammation and immunity. However, current zebrafish imaging techniques, such as agraose mounting, can be time-consuming and detrimental for long-term imaging. Alternatively, automated sorting and imaging systems can be costly and/or complicated to assemble. Here we describe the Zebrafish Entrapment by Restriction Array (ZEBRA) device, a microfluidic device that can be used to quickly and repeatably position zebrafish embryos in a predictable array using only a pipette. This technique is well suited for use with automated microscope stages leading to decreased imaging time and increased throughput compared to traditional methods. The addition of access ports above the embryo can be used to administer treatments, and potentially wounding or injections. We demonstrate the effectiveness of this device for a neutrophil migration screening application using larvae 3 days post fertilization (dpf) Tg(mpx:dendra2). Larvae were loaded into ZEBRA devices and treated with a neutrophil attractant (LTB4) or LTB4 with and without a PI3K inhibitor, LY294002. Treatment with LY294002 impaired neutrophil motility into the fin induced by LTB4 treatment. The findings report the development of ZEBRA a device that can be used to screen for small molecules that affect leukocyte motility and inflammation using live zebrafish.
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Affiliation(s)
- Lauren L. Bischel
- Department of Biomedical Engineering, Wisconsin Institute for Medical Research, University of Wisconsin-Madison, 1111 Highland Ave, Madison, WI, USA. Tel: +1-608-262-2260
| | - Brianah R. Mader
- Department of Biomedical Engineering, Wisconsin Institute for Medical Research, University of Wisconsin-Madison, 1111 Highland Ave, Madison, WI, USA. Tel: +1-608-262-2260
| | - Julie M. Green
- Department of Paediatrics, University of Wisconsin-Madison, Madison, WI, USA
| | - Anna Huttenlocher
- Department of Paediatrics, University of Wisconsin-Madison, Madison, WI, USA
| | - David J. Beebe
- Department of Biomedical Engineering, Wisconsin Institute for Medical Research, University of Wisconsin-Madison, 1111 Highland Ave, Madison, WI, USA. Tel: +1-608-262-2260
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209
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de Oliveira S, Reyes-Aldasoro CC, Candel S, Renshaw SA, Mulero V, Calado Â. Cxcl8 (IL-8) mediates neutrophil recruitment and behavior in the zebrafish inflammatory response. JOURNAL OF IMMUNOLOGY (BALTIMORE, MD. : 1950) 2013; 190:4349-59. [PMID: 23509368 PMCID: PMC3736093 DOI: 10.4049/jimmunol.1203266] [Citation(s) in RCA: 244] [Impact Index Per Article: 22.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Neutrophils play a pivotal role in the innate immune response. The small cytokine CXCL8 (also known as IL-8) is known to be one of the most potent chemoattractant molecules that, among several other functions, is responsible for guiding neutrophils through the tissue matrix until they reach sites of injury. Unlike mice and rats that lack a CXCL8 homolog, zebrafish has two distinct CXCL8 homologs: Cxcl8-l1 and Cxcl8-l2. Cxcl8-l1 is known to be upregulated under inflammatory conditions caused by bacterial or chemical insult but until now the role of Cxcl8s in neutrophil recruitment has not been studied. In this study we show that both Cxcl8 genes are upregulated in response to an acute inflammatory stimulus, and that both are crucial for normal neutrophil recruitment to the wound and normal resolution of inflammation. Additionally, we have analyzed neutrophil migratory behavior through tissues to the site of injury in vivo, using open-access phagocyte tracking software PhagoSight. Surprisingly, we observed that in the absence of these chemokines, the speed of the neutrophils migrating to the wound was significantly increased in comparison with control neutrophils, although the directionality was not affected. Our analysis suggests that zebrafish may possess a subpopulation of neutrophils whose recruitment to inflamed areas occurs independently of Cxcl8 chemokines. Moreover, we report that Cxcl8-l2 signaled through Cxcr2 for inducing neutrophil recruitment. Our study, therefore, confirms the zebrafish as an excellent in vivo model to shed light on the roles of CXCL8 in neutrophil biology.
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Affiliation(s)
- Sofia de Oliveira
- Unidade de Biologia Microvascular e Inflamação, Instituto de Medicina Molecular, Instituto de Bioquímica, Faculdade de Medicina, Universidade de Lisboa, Lisboa-Portugal
- Department of Cell Biology and Histology, Faculty of Biology, University of Murcia, Murcia-Spain
| | - Constantino C. Reyes-Aldasoro
- Biomedical Engineering Research Group, School of Engineering and Design, University of Sussex, Brighton BN1 9QT – United Kingdom
| | - Sergio Candel
- Department of Cell Biology and Histology, Faculty of Biology, University of Murcia, Murcia-Spain
| | - Stephen A. Renshaw
- MRC Centre for Developmental and Biomedical Genetics, University of Sheffield, Firth Court, Western Bank, Sheffield – United Kingdom
| | - Victoriano Mulero
- Department of Cell Biology and Histology, Faculty of Biology, University of Murcia, Murcia-Spain
| | - Ângelo Calado
- Unidade de Biologia Microvascular e Inflamação, Instituto de Medicina Molecular, Instituto de Bioquímica, Faculdade de Medicina, Universidade de Lisboa, Lisboa-Portugal
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210
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Deng Q, Sarris M, Bennin DA, Green JM, Herbomel P, Huttenlocher A. Localized bacterial infection induces systemic activation of neutrophils through Cxcr2 signaling in zebrafish. J Leukoc Biol 2013; 93:761-9. [PMID: 23475575 DOI: 10.1189/jlb.1012534] [Citation(s) in RCA: 83] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023] Open
Abstract
Neutrophils are the first line of defense against tissue damage and are rapidly mobilized to sites of bacterial infection. However, the signals that regulate neutrophil recruitment are not well defined. Here, using photolabel-enabled fate mapping in zebrafish larvae, we show that localized otic infection with Pseudomonas aeruginosa induces systemic activation and mobilization of neutrophils from the CHT through Cxcr2 signaling. We have cloned the zebrafish Cxcr1 and Cxcr2 receptors and show that Cxcr2 functions as a Cxcl8 receptor in live zebrafish. With the use of morpholino-mediated depletion, we show that infection-induced neutrophil mobilization from the CHT is mediated by Cxcr2 but not Cxcr1. By contrast, Cxcr2 depletion does not affect neutrophil recruitment to the chemoattractant LTB4. Taken together, our findings identify Cxcl8-Cxcr2 signaling as an infection-induced long-range cue that mediates neutrophil motility and mobilization from hematopoietic tissues, positioning Cxcr2 as a critical pathway that mediates infection-induced systemic activation of neutrophils.
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Affiliation(s)
- Qing Deng
- Department of Medical Microbiology and Immunology, University of Wisconsin-Madison, Madison, Wisconsin 53706, USA
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211
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Henry KM, Loynes CA, Whyte MKB, Renshaw SA. Zebrafish as a model for the study of neutrophil biology. J Leukoc Biol 2013; 94:633-42. [PMID: 23463724 DOI: 10.1189/jlb.1112594] [Citation(s) in RCA: 106] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023] Open
Abstract
To understand inflammation and immunity, we need to understand the biology of the neutrophil. Whereas these cells can readily be extracted from peripheral blood, their short lifespan makes genetic manipulations impractical. Murine knockout models have been highly informative, and new imaging techniques are allowing neutrophils to be seen during inflammation in vivo for the first time. However, there is a place for a new model of neutrophil biology, which readily permits imaging of individual neutrophils during inflammation in vivo, combined with the ease of genetic and chemical manipulation. The zebrafish has long been the model of choice for the developmental biology community, and the availability of genomic resources and tools for gene manipulation makes this an attractive model. Zebrafish innate immunity shares many features with mammalian systems, including neutrophils with morphological, biochemical, and functional features, also shared with mammalian neutrophils. Transgenic zebrafish with neutrophils specifically labeled with fluorescent proteins have been generated, and this advance has led to the adoption of zebrafish, alongside existing models, by a number of groups around the world. The use of these models has underpinned a number of key advances in the field, including the identification of a tissue gradient of hydrogen peroxide for neutrophil recruitment following tissue injury and direct evidence for reverse migration as a regulatable mechanism of inflammation resolution. In this review, we discuss the importance of zebrafish models in neutrophil biology and describe how the understanding of neutrophil biology has been advanced by the use of these models.
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212
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Li H, Hou S, Wu X, Nandagopal S, Lin F, Kung S, Marshall AJ. The tandem PH domain-containing protein 2 (TAPP2) regulates chemokine-induced cytoskeletal reorganization and malignant B cell migration. PLoS One 2013; 8:e57809. [PMID: 23460911 PMCID: PMC3583899 DOI: 10.1371/journal.pone.0057809] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2012] [Accepted: 01/26/2013] [Indexed: 11/25/2022] Open
Abstract
The intracellular signaling processes controlling malignant B cell migration and tissue localization remain largely undefined. Tandem PH domain-containing proteins TAPP1 and TAPP2 are adaptor proteins that specifically bind to phosphatidylinositol-3,4-bisphosphate, or PI(3,4)P2, a product of phosphoinositide 3-kinases (PI3K). While PI3K enzymes have a number of functions in cell biology, including cell migration, the functions of PI(3,4)P2 and its binding proteins are not well understood. Previously we found that TAPP2 is highly expressed in primary leukemic B cells that have strong migratory capacity. Here we find that SDF-1-dependent migration of human malignant B cells requires both PI3K signaling and TAPP2. Migration in a transwell assay is significantly impaired by pan-PI3K and isoform-selective PI3K inhibitors, or by TAPP2 shRNA knockdown (KD). Strikingly, TAPP2 KD in combination with PI3K inhibitor treatment nearly abolished the migration response, suggesting that TAPP2 may contribute some functions independent of the PI3K pathway. In microfluidic chamber cell tracking assays, TAPP2 KD cells show reduction in percentage of migrating cells, migration velocity and directionality. TAPP2 KD led to alterations in chemokine-induced rearrangement of the actin cytoskeleton and failure to form polarized morphology. TAPP2 co-localized with the stable F-actin-binding protein utrophin, with both molecules reciprocally localizing against F-actin accumulated at the leading edge upon SDF-1 stimulation. In TAPP2 KD cells, Rac was over-activated and localized to multiple membrane protrusions, suggesting that TAPP2 may act in concert with utrophin and stable F-actin to spatially restrict Rac activation and reduce formation of multiple membrane protrusions. TAPP2 function in cell migration is also apparent in the more complex context of B cell migration into stromal cell layers – a process that is only partially dependent on PI3K and SDF-1. In summary, this study identified TAPP2 as a novel regulator of malignant B cell migration and a potential therapeutic intervention target.
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Affiliation(s)
- Hongzhao Li
- Department of Immunology, University of Manitoba, Winnipeg, Manitoba, Canada
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213
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Yin T, Wu YI. Guiding lights: recent developments in optogenetic control of biochemical signals. Pflugers Arch 2013; 465:397-408. [PMID: 23417571 DOI: 10.1007/s00424-013-1244-x] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2013] [Accepted: 02/05/2013] [Indexed: 10/27/2022]
Abstract
Optogenetics arises from the innovative application of microbial opsins in mammalian neurons and has since been a powerful technology that fuels the advance of our knowledge in neuroscience. In recent years, there has been growing interest in designing optogenetic tools extendable to broader cell types and biochemical signals. To date, a variety of photoactivatable proteins (refers to induction of protein activity in contrast to fluorescence) have been developed based on the understanding of plant and microbial photoreceptors including phototropins, blue light sensors using flavin adenine dinucleotide proteins, cryptochromes, and phytochromes. Such tools offered researchers reversible, quantitative, and precise spatiotemporal control of enzymatic activity, protein-protein interaction, protein translocation, as well as gene transcription in cells and in whole animals. In this review, we will briefly introduce these photosensory proteins, describe recent developments in optogenetics, and compare and contrast different methods based on their advantages and limitations.
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Affiliation(s)
- Taofei Yin
- Robert D. Berlin Center for Cell Analysis & Modeling, Department of Genetics & Developmental Biology, University of Connecticut Health Center, Farmington, CT 06032, USA
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214
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Woo S, Housley MP, Weiner OD, Stainier DYR. Nodal signaling regulates endodermal cell motility and actin dynamics via Rac1 and Prex1. ACTA ACUST UNITED AC 2013; 198:941-52. [PMID: 22945937 PMCID: PMC3432772 DOI: 10.1083/jcb.201203012] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023]
Abstract
Nodal, acting through Prex1 and Rac1, promotes dynamic actin and random motility in endodermal cells during early gastrulation. Embryo morphogenesis is driven by dynamic cell behaviors, including migration, that are coordinated with fate specification and differentiation, but how such coordination is achieved remains poorly understood. During zebrafish gastrulation, endodermal cells sequentially exhibit first random, nonpersistent migration followed by oriented, persistent migration and finally collective migration. Using a novel transgenic line that labels the endodermal actin cytoskeleton, we found that these stage-dependent changes in migratory behavior correlated with changes in actin dynamics. The dynamic actin and random motility exhibited during early gastrulation were dependent on both Nodal and Rac1 signaling. We further identified the Rac-specific guanine nucleotide exchange factor Prex1 as a Nodal target and showed that it mediated Nodal-dependent random motility. Reducing Rac1 activity in endodermal cells caused them to bypass the random migration phase and aberrantly contribute to mesodermal tissues. Together, our results reveal a novel role for Nodal signaling in regulating actin dynamics and migration behavior, which are crucial for endodermal morphogenesis and cell fate decisions.
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Affiliation(s)
- Stephanie Woo
- Department of Biochemistry and Biophysics, University of California, San Francisco, San Francisco, CA 94158, USA.
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215
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Choe CP, Collazo A, Trinh LA, Pan L, Moens CB, Crump JG. Wnt-dependent epithelial transitions drive pharyngeal pouch formation. Dev Cell 2013; 24:296-309. [PMID: 23375584 DOI: 10.1016/j.devcel.2012.12.003] [Citation(s) in RCA: 59] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2011] [Revised: 10/18/2012] [Accepted: 12/03/2012] [Indexed: 01/15/2023]
Abstract
The pharyngeal pouches, which form by budding of the foregut endoderm, are essential for segmentation of the vertebrate face. To date, the cellular mechanism and segmental nature of such budding have remained elusive. Here, we find that Wnt11r and Wnt4a from the head mesoderm and ectoderm, respectively, play distinct roles in the segmental formation of pouches in zebrafish. Time-lapse microscopy, combined with mutant and tissue-specific transgenic experiments, reveal requirements of Wnt signaling in two phases of endodermal epithelial transitions. Initially, Wnt11r and Rac1 destabilize the endodermal epithelium to promote the lateral movement of pouch-forming cells. Next, Wnt4a and Cdc42 signaling induce the rearrangement of maturing pouch cells into bilayers through junctional localization of the Alcama immunoglobulin-domain protein, which functions to restabilize adherens junctions. We propose that this dynamic control of epithelial morphology by Wnt signaling may be a common theme for the budding of organ anlagen from the endoderm.
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Affiliation(s)
- Chong Pyo Choe
- Broad California Institute of Regenerative Medicine Center, Keck School of Medicine, University of Southern California, Los Angeles, CA 90033, USA
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216
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Group choreography: mechanisms orchestrating the collective movement of border cells. Nat Rev Mol Cell Biol 2012; 13:631-45. [PMID: 23000794 DOI: 10.1038/nrm3433] [Citation(s) in RCA: 170] [Impact Index Per Article: 14.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Cell movements are essential for animal development and homeostasis but also contribute to disease. Moving cells typically extend protrusions towards a chemoattractant, adhere to the substrate, contract and detach at the rear. It is less clear how cells that migrate in interconnected groups in vivo coordinate their behaviour and navigate through natural environments. The border cells of the Drosophila melanogaster ovary have emerged as an excellent model for the study of collective cell movement, aided by innovative genetic, live imaging, and photomanipulation techniques. Here we provide an overview of the molecular choreography of border cells and its more general implications.
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217
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Sarris M, Masson JB, Maurin D, Van der Aa LM, Boudinot P, Lortat-Jacob H, Herbomel P. Inflammatory chemokines direct and restrict leukocyte migration within live tissues as glycan-bound gradients. Curr Biol 2012; 22:2375-82. [PMID: 23219724 DOI: 10.1016/j.cub.2012.11.018] [Citation(s) in RCA: 119] [Impact Index Per Article: 9.9] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2012] [Revised: 10/01/2012] [Accepted: 11/07/2012] [Indexed: 11/24/2022]
Abstract
Chemokines are essential in many cell migration processes, including the recruitment of leukocytes to sites of infection. In the latter context, chemokines promote leukocyte extravasation into the relevant tissue through a well-studied cascade of events. It is widely believed that chemokines further guide leukocytes within tissues via chemotaxis, the directed migration along gradients of soluble ligands. However, the basic mechanism of chemokine action within tissues has yet to be formally addressed in vivo. We identified a chemokine (zCxcl8) that recruits zebrafish neutrophils to infection loci and analyzed its function directly within interstitial tissues of living larvae. Using noninvasive imaging and a controlled cellular source of zCxcl8, we found that zCxcl8 guides neutrophils in a 2-fold manner: by biasing cell speed according to direction (orthotaxis) and by restricting cell motility near the source. We further show that zCxcl8 establishes tissue-bound gradients in vivo by binding to heparan sulfate proteoglycans (HSPGs). Inhibition of this interaction compromised both directional guidance and restriction of neutrophil motility. Thus, by interacting with extracellular HSPGs, chemokines establish robust surface-bound (haptotactic) gradients that mediate both recruitment and retention of leukocytes at sites of infection.
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Affiliation(s)
- Milka Sarris
- Macrophages and Development of Immunity Unit, Department of Developmental and Stem Cell Biology, Institut Pasteur, Paris, France.
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218
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Synthetic spatially graded Rac activation drives cell polarization and movement. Proc Natl Acad Sci U S A 2012. [PMID: 23185021 DOI: 10.1073/pnas.1210295109] [Citation(s) in RCA: 55] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Migrating cells possess intracellular gradients of active Rho GTPases, which serve as central hubs in transducing signals from extracellular receptors to cytoskeletal and adhesive machinery. However, it is unknown whether shallow exogenously induced intracellular gradients of Rho GTPases are sufficient to drive cell polarity and motility. Here, we use microfluidic control to generate gradients of a small molecule and thereby directly induce linear gradients of active, endogenous Rac without activation of chemotactic receptors. Gradients as low as 15% were sufficient not only to trigger cell migration up the chemical gradient but to induce both cell polarization and repolarization. Cellular response times were inversely proportional to the steepness of Rac inducer gradient in agreement with a mathematical model, suggesting a function for chemoattractant gradient amplification upstream of Rac. Increases in activated Rac levels beyond a well-defined threshold augmented polarization and decreased sensitivity to the imposed gradient. The threshold was governed by initial cell polarity and PI3K activity, supporting a role for both in defining responsiveness to Rac activation. Our results reveal that Rac can serve as a starting point in defining cell polarity. Furthermore, our methodology may serve as a template to investigate processes regulated by intracellular signaling gradients.
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219
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Affiliation(s)
- K. KEMP-O'BRIEN
- Randall Division of Cell and Molecular Biophysics; King's College London; London; SE1 1UL; U.K
| | - M. PARSONS
- Randall Division of Cell and Molecular Biophysics; King's College London; London; SE1 1UL; U.K
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220
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Santiago-Medina M, Myers JP, Gomez TM. Imaging adhesion and signaling dynamics in Xenopus laevis growth cones. Dev Neurobiol 2012; 72:585-99. [PMID: 21465668 DOI: 10.1002/dneu.20886] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
Xenopus laevis provides a robust model system to study cellular signaling and downstream processes during development both in vitro and in vivo. Intracellular signals must function within highly restricted spatial and temporal domains to activate specific downstream targets and cellular processes. Combining the versatility of developing Xenopus neurons with advances in fluorescent protein biosensors and imaging technologies has allowed many dynamic cellular processes to be visualized. This review will focus on the techniques we use to visualize and measure cell signaling, motility and adhesion by quantitative fluorescence microscopy in vitro and in vivo.
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Affiliation(s)
- Miguel Santiago-Medina
- Department of Neuroscience, Neuroscience Training Program, University of Wisconsin-Madison, WI 53706, USA
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221
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Lee J, Veatch SL, Baird B, Holowka D. Molecular mechanisms of spontaneous and directed mast cell motility. J Leukoc Biol 2012; 92:1029-41. [PMID: 22859829 PMCID: PMC3476239 DOI: 10.1189/jlb.0212091] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2012] [Revised: 07/02/2012] [Accepted: 07/16/2012] [Indexed: 01/01/2023] Open
Abstract
Migration is a fundamental function of immune cells, and a role for Ca(2+) in immune cell migration has been an interest of scientific investigations for many decades. Mast cells are the major effector cells in IgE-mediated immune responses, and cross-linking of IgE-FcεRI complexes at the mast cell surface by antigen activates a signaling cascade that causes mast cell activation, resulting in Ca(2+) mobilization and granule exocytosis. These cells are known to accumulate at sites of inflammation in response to parasite and bacterial infections. Using real-time imaging, we monitored chemotactic migration of RBL and rat BMMCs in response to a gradient of soluble multivalent antigen. Here, we show that Ca(2+) influx via Orai1 plays an important role in regulating spontaneous motility and directional migration of mast cells toward antigen via IgER complexes. Inhibition of Ca(2+) influx or knockdown of the Ca(2+) entry channel protein Orai1 by shRNA causes inhibition of both of these processes. In addition, a mutant Syk- shows impaired spontaneous motility and chemotaxis toward antigen that is rescued by expression of Syk. Our findings identify a novel Ca(2+) influx-mediated, Orai1-dependent mechanism for mast cell migration.
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Affiliation(s)
- Jinmin Lee
- Department of Chemistry and Chemical Biology, Cornell University, Ithaca, New York, USA
| | | | - Barbara Baird
- Department of Chemistry and Chemical Biology, Cornell University, Ithaca, New York, USA
| | - David Holowka
- Department of Chemistry and Chemical Biology, Cornell University, Ithaca, New York, USA
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222
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Yoo SK, Freisinger CM, LeBert DC, Huttenlocher A. Early redox, Src family kinase, and calcium signaling integrate wound responses and tissue regeneration in zebrafish. ACTA ACUST UNITED AC 2012; 199:225-34. [PMID: 23045550 PMCID: PMC3471241 DOI: 10.1083/jcb.201203154] [Citation(s) in RCA: 152] [Impact Index Per Article: 12.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Abstract
Redox, SFK, and calcium signaling are immediate “wound signals” that integrate early wound responses and late epimorphic regeneration. Tissue injury can lead to scar formation or tissue regeneration. How regenerative animals sense initial tissue injury and transform wound signals into regenerative growth is an unresolved question. Previously, we found that the Src family kinase (SFK) Lyn functions as a redox sensor in leukocytes that detects H2O2 at wounds in zebrafish larvae. In this paper, using zebrafish larval tail fins as a model, we find that wounding rapidly activated SFK and calcium signaling in epithelia. The immediate SFK and calcium signaling in epithelia was important for late epimorphic regeneration of amputated fins. Wound-induced activation of SFKs in epithelia was dependent on injury-generated H2O2. A SFK member, Fynb, was responsible for fin regeneration. This work provides a new link between early wound responses and late regeneration and suggests that redox, SFK, and calcium signaling are immediate “wound signals” that integrate early wound responses and late epimorphic regeneration.
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Affiliation(s)
- Sa Kan Yoo
- Program in Cellular and Molecular Biology, University of Wisconsin-Madison, Madison, WI 53706, USA
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223
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Yoo SK, Lam PY, Eichelberg MR, Zasadil L, Bement WM, Huttenlocher A. The role of microtubules in neutrophil polarity and migration in live zebrafish. J Cell Sci 2012; 125:5702-10. [PMID: 22992461 DOI: 10.1242/jcs.108324] [Citation(s) in RCA: 65] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
Microtubules control cell motility by positively regulating polarization in many cell types. However, how microtubules regulate leukocyte migration is not well understood, particularly in living organisms. Here we exploited the zebrafish system to study the role of microtubules in neutrophil migration in vivo. The localization of microtubules was visualized in motile neutrophils using various bioprobes, revealing that, in contrast to what has been seen in studies in vitro, the microtubule organizing center is positioned in front of the nucleus (relative to the direction of migration) in motile neutrophils. Microtubule disassembly impaired attraction of neutrophils to wounds but enhanced the polarity of F-actin dynamics as measured by the distribution of stable and dynamic F-actin. Microtubule depolymerization inhibited polarized phosphoinositol 3-kinase (PI(3)K) activation at the leading edge and induced rapid PI(3)K independent motility. Finally, we show that microtubules exert their effects on neutrophil polarity and motility at least in part by the negative regulation of both Rho and Rac activity. These results provide new insight into the role of microtubules in neutrophil migration in a living vertebrate and show that the motility of these professional migratory cells are subject to distinctly different rules from those established for other cell types.
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Affiliation(s)
- Sa Kan Yoo
- Program in Cellular and Molecular Biology, University of Wisconsin-Madison, 1525 Linden Drive, Madison, WI 53706, USA
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224
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Stulberg MJ, Lin A, Zhao H, Holley SA. Crosstalk between Fgf and Wnt signaling in the zebrafish tailbud. Dev Biol 2012; 369:298-307. [PMID: 22796649 PMCID: PMC3423502 DOI: 10.1016/j.ydbio.2012.07.003] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2012] [Revised: 06/26/2012] [Accepted: 07/02/2012] [Indexed: 01/09/2023]
Abstract
Fibroblast growth factor (Fgf) and Wnt signaling are necessary for the intertwined processes of tail elongation, mesodermal development and somitogenesis. Here, we use pharmacological modifiers and time-resolved quantitative analysis of both nascent transcription and protein phosphorylation in the tailbud, to distinguish early effects of signal perturbation from later consequences related to cell fate changes. We demonstrate that Fgf activity elevates Wnt signaling by inhibiting transcription of the Wnt antagonists dkk1 and notum1a. PI3 kinase signaling also increases Wnt signaling via phosphorylation of Gsk3β. Conversely, Wnt can increase signaling within the Mapk branch of the Fgf pathway as Gsk3β phosphorylation elevates phosphorylation levels of Erk. Despite the reciprocal positive regulation between Fgf and Wnt, the two pathways generally have opposing effects on the transcription of co-regulated genes. This opposing regulation of target genes may represent a rudimentary relationship that manifests as out-of-phase oscillation of Fgf and Wnt target genes in the mouse and chick tailbud. In summary, these data suggest that Fgf and Wnt signaling are tightly integrated to maintain proportional levels of activity in the zebrafish tailbud, and this balance is important for axis elongation, cell fate specification and somitogenesis.
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Affiliation(s)
- Michael J. Stulberg
- Department of Molecular, Cellular, and Developmental Biology, Yale University, New Haven, CT 06511, USA
| | - Aiping Lin
- Keck Biostatistics Resource, Yale University, New Haven, CT 06511, USA
| | - Hongyu Zhao
- Keck Biostatistics Resource, Yale University, New Haven, CT 06511, USA
- Department of Epidemiology and Public Health, Yale University, New Haven, CT 06511, USA
| | - Scott A. Holley
- Department of Molecular, Cellular, and Developmental Biology, Yale University, New Haven, CT 06511, USA
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225
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Lam PY, Yoo SK, Green JM, Huttenlocher A. The SH2-domain-containing inositol 5-phosphatase (SHIP) limits the motility of neutrophils and their recruitment to wounds in zebrafish. J Cell Sci 2012; 125:4973-8. [PMID: 22946052 DOI: 10.1242/jcs.106625] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
Neutrophil recruitment to sites of injury or infection is essential for host defense, but it needs to be tightly regulated to prevent tissue damage. Phosphoinositide 3-kinase (PI3K), which generates the phosphatidylinositol (3,4,5)-trisphosphate [PI(3,4,5)P(3)], is necessary for neutrophil motility in vivo; however, the role of SH2-domain-containing 5-inositol phosphatase (SHIP) enzymes, which hydrolyze PI(3,4,5)P(3) to phosphatidylinositol 3,4-bisphosphate [PI(3,4)P(2)], is not well understood. Here we show that SHIP phosphatases limit neutrophil motility in live zebrafish. Using real-time imaging of bioprobes specific for PI(3,4,5)P(3) and PI(3,4)P(2) in neutrophils, we found that PI(3,4,5)P(3) and PI(3,4)P(2) accumulate at the leading edge while PI(3,4)P(2) also localizes to the trailing edge of migrating neutrophils in vivo. Depletion of SHIP phosphatases using morpholino oligonucleotides led to increased neutrophil 3D motility and neutrophil infiltration into wounds. The increase in neutrophil wound recruitment in SHIP morphants was rescued by treatment with low dose PI3Kγ inhibitor, suggesting that SHIP limits neutrophil motility by modulating PI3K signaling. Moreover, overexpression of the SHIP phosphatase domain in neutrophils impaired neutrophil 3D migration. Taken together, our findings suggest that SHIP phosphatases control neutrophil inflammation by limiting neutrophil motility in vivo.
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Affiliation(s)
- Pui-ying Lam
- Department of Medical Microbiology and Immunology; University of Wisconsin-Madison, Madison, WI 53706, USA
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226
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Guo Q, Wang X, Tibbitt MW, Anseth KS, Montell DJ, Elisseeff JH. Light activated cell migration in synthetic extracellular matrices. Biomaterials 2012; 33:8040-6. [PMID: 22889487 DOI: 10.1016/j.biomaterials.2012.07.013] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2012] [Accepted: 07/05/2012] [Indexed: 10/28/2022]
Abstract
Synthetic extracellular matrices provide a framework in which cells can be exposed to defined physical and biological cues. However no method exists to manipulate single cells within these matrices. It is desirable to develop such methods in order to understand fundamental principles of cell migration and define conditions that support or inhibit cell movement within these matrices. Here, we present a strategy for manipulating individual mammalian stem cells in defined synthetic hydrogels through selective optical activation of Rac, which is an intracellular signaling protein that plays a key role in cell migration. Photoactivated cell migration in synthetic hydrogels depended on mechanical and biological cues in the biomaterial. Real-time hydrogel photodegradation was employed to create geometrically defined channels and spaces in which cells could be photoactivated to migrate. Cell migration speed was significantly higher in the photo-etched channels and cells could easily change direction of movement compared to the bulk hydrogels.
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Affiliation(s)
- Qiongyu Guo
- Translational Tissue Engineering Center, Wilmer Eye Institute and Department of Biomedical Engineering, Johns Hopkins School of Medicine, Baltimore, MD 21231, USA
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227
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Taormina MJ, Jemielita M, Stephens WZ, Burns AR, Troll JV, Parthasarathy R, Guillemin K. Investigating bacterial-animal symbioses with light sheet microscopy. THE BIOLOGICAL BULLETIN 2012; 223:7-20. [PMID: 22983029 PMCID: PMC3952068 DOI: 10.1086/bblv223n1p7] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
Microbial colonization of the digestive tract is a crucial event in vertebrate development, required for maturation of host immunity and establishment of normal digestive physiology. Advances in genomic, proteomic, and metabolomic technologies are providing a more detailed picture of the constituents of the intestinal habitat, but these approaches lack the spatial and temporal resolution needed to characterize the assembly and dynamics of microbial communities in this complex environment. We report the use of light sheet microscopy to provide high-resolution imaging of bacterial colonization of the intestine of Danio rerio, the zebrafish. The method allows us to characterize bacterial population dynamics across the entire organ and the behaviors of individual bacterial and host cells throughout the colonization process. The large four-dimensional data sets generated by these imaging approaches require new strategies for image analysis. When integrated with other "omics" data sets, information about the spatial and temporal dynamics of microbial cells within the vertebrate intestine will provide new mechanistic insights into how microbial communities assemble and function within hosts.
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Affiliation(s)
| | | | - W. Zac Stephens
- Institute of Molecular Biology, University of Oregon, Eugene OR 97403
| | - Adam R. Burns
- Institute of Ecology and Evolution, University of Oregon, Eugene OR 97403
| | - Joshua V. Troll
- Institute of Molecular Biology, University of Oregon, Eugene OR 97403
| | - Raghuveer Parthasarathy
- Department of Physics, University of Oregon, Eugene OR 97403
- Institute of Molecular Biology, University of Oregon, Eugene OR 97403
- Materials Science Institute, University of Oregon, Eugene OR 97403
| | - Karen Guillemin
- Institute of Molecular Biology, University of Oregon, Eugene OR 97403
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228
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Mechanical stretch and PI3K signaling link cell migration and proliferation to coordinate epithelial tubule morphogenesis in the zebrafish pronephros. PLoS One 2012; 7:e39992. [PMID: 22815719 PMCID: PMC3399848 DOI: 10.1371/journal.pone.0039992] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2011] [Accepted: 06/05/2012] [Indexed: 12/31/2022] Open
Abstract
Organ development leads to the emergence of organ function, which in turn can impact developmental processes. Here we show that fluid flow-induced collective epithelial migration during kidney nephron morphogenesis induces cell stretch that in turn signals epithelial proliferation. Increased cell proliferation was dependent on PI3K signaling. Inhibiting epithelial proliferation by blocking PI3K or CDK4/Cyclin D1 activity arrested cell migration prematurely and caused a marked overstretching of the distal nephron tubule. Computational modeling of the involved cell processes predicted major morphological and kinetic outcomes observed experimentally under a variety of conditions. Overall, our findings suggest that kidney development is a recursive process where emerging organ function "feeds back" to the developmental program to influence fundamental cellular events such as cell migration and proliferation, thus defining final organ morphology.
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229
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Neutrophil reverse migration becomes transparent with zebrafish. Adv Hematol 2012; 2012:398640. [PMID: 22844288 PMCID: PMC3401556 DOI: 10.1155/2012/398640] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2012] [Accepted: 05/08/2012] [Indexed: 01/06/2023] Open
Abstract
The precise control of neutrophil-mediated inflammation is critical for both host defense and the prevention of immunopathology. In vivo imaging studies in zebrafish, and more recently in mice, have made the novel observation that neutrophils leave a site of inflammation through a process called neutrophil reverse migration. The application of advanced imaging techniques to the genetically tractable, optically transparent zebrafish larvae was critical for these advances. Still, the mechanisms underlying neutrophil reverse migration and its effects on the resolution or priming of immune responses remain unclear. Here, we review the current knowledge of neutrophil reverse migration, its potential roles in host immunity, and the live imaging tools that make zebrafish a valuable model for increasing our knowledge of neutrophil behavior in vivo.
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230
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Abstract
Protein conformational switches alter their shape upon receiving an input signal, such as ligand binding, chemical modification, or change in environment. The apparent simplicity of this transformation--which can be carried out by a molecule as small as a thousand atoms or so--belies its critical importance to the life of the cell as well as its capacity for engineering by humans. In the realm of molecular switches, proteins are unique because they are capable of performing a variety of biological functions. Switchable proteins are therefore of high interest to the fields of biology, biotechnology, and medicine. These molecules are beginning to be exploited as the core machinery behind a new generation of biosensors, functionally regulated enzymes, and "smart" biomaterials that react to their surroundings. As inspirations for these designs, researchers continue to analyze existing examples of allosteric proteins. Recent years have also witnessed the development of new methodologies for introducing conformational change into proteins that previously had none. Herein we review examples of both natural and engineered protein switches in the context of four basic modes of conformational change: rigid-body domain movement, limited structural rearrangement, global fold switching, and folding-unfolding. Our purpose is to highlight examples that can potentially serve as platforms for the design of custom switches. Accordingly, we focus on inducible conformational changes that are substantial enough to produce a functional response (e.g., in a second protein to which it is fused), yet are relatively simple, structurally well-characterized, and amenable to protein engineering efforts.
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Affiliation(s)
| | - Stewart N. Loh
- Department of Biochemistry & Molecular Biology, State University of New York Upstate Medical University, 750 East Adams Street, Syracuse, NY 13210 (USA), Tel: (315)464-8731, Fax: (315)464-8750
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231
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Petrie RJ, Gavara N, Chadwick RS, Yamada KM. Nonpolarized signaling reveals two distinct modes of 3D cell migration. ACTA ACUST UNITED AC 2012; 197:439-55. [PMID: 22547408 PMCID: PMC3341168 DOI: 10.1083/jcb.201201124] [Citation(s) in RCA: 278] [Impact Index Per Article: 23.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
The elastic behavior of the 3D extracellular matrix determines the relative polarization of intracellular signaling and whether cells migrate using lamellipodia or lobopodia. We search in this paper for context-specific modes of three-dimensional (3D) cell migration using imaging for phosphatidylinositol (3,4,5)-trisphosphate (PIP3) and active Rac1 and Cdc42 in primary fibroblasts migrating within different 3D environments. In 3D collagen, PIP3 and active Rac1 and Cdc42 were targeted to the leading edge, consistent with lamellipodia-based migration. In contrast, elongated cells migrating inside dermal explants and the cell-derived matrix (CDM) formed blunt, cylindrical protrusions, termed lobopodia, and Rac1, Cdc42, and PIP3 signaling was nonpolarized. Reducing RhoA, Rho-associated protein kinase (ROCK), or myosin II activity switched the cells to lamellipodia-based 3D migration. These modes of 3D migration were regulated by matrix physical properties. Specifically, experimentally modifying the elasticity of the CDM or collagen gels established that nonlinear elasticity supported lamellipodia-based migration, whereas linear elasticity switched cells to lobopodia-based migration. Thus, the relative polarization of intracellular signaling identifies two distinct modes of 3D cell migration governed intrinsically by RhoA, ROCK, and myosin II and extrinsically by the elastic behavior of the 3D extracellular matrix.
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Affiliation(s)
- Ryan J Petrie
- Laboratory of Cell and Developmental Biology, National Institute of Dental and Craniofacial Research, National Institute on Deafness and Other Communication Disorders, National Institutes of Health, Bethesda, MD 20892, USA.
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232
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In vivo chemical screening for modulators of hematopoiesis and hematological diseases. Adv Hematol 2012; 2012:851674. [PMID: 22778745 PMCID: PMC3385708 DOI: 10.1155/2012/851674] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2012] [Accepted: 04/26/2012] [Indexed: 12/13/2022] Open
Abstract
In vivo chemical screening is a broadly applicable approach not only for dissecting genetic pathways governing hematopoiesis and hematological diseases, but also for finding critical components in those pathways that may be pharmacologically modulated. Both high-throughput chemical screening and facile detection of blood-cell-related phenotypes are feasible in embryonic/larval zebrafish. Two recent studies utilizing phenotypic chemical screens in zebrafish have identified several compounds that promote hematopoietic stem cell formation and reverse the hematopoietic phenotypes of a leukemia oncogene, respectively. These studies illustrate efficient drug discovery processes in zebrafish and reveal novel biological roles of prostaglandin E2 in hematopoietic and leukemia stem cells. Furthermore, the compounds discovered in zebrafish screens have become promising therapeutic candidates against leukemia and included in a clinical trial for enhancing hematopoietic stem cells during hematopoietic cell transplantation.
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233
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Jayo A, Parsons M. Imaging of cell adhesion events in 3D matrix environments. Eur J Cell Biol 2012; 91:824-33. [PMID: 22705211 DOI: 10.1016/j.ejcb.2012.05.002] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2012] [Revised: 05/08/2012] [Accepted: 05/08/2012] [Indexed: 01/28/2023] Open
Abstract
Cell adhesion plays an essential role in development and homeostasis, but is also a key regulator of many diseases such as cancer and immune dysfunction. Numerous studies over the past three decades have revealed a wealth of information detailing signalling molecules required for cell adhesion to two-dimensional surfaces. However, in vivo many cells are completely surrounded by matrix and this will very likely influence the size, composition and dynamics of adhesive structures. The study of adhesion in cells within three-dimensional environments is still in its infancy, thus the role and regulation of adhesions in these complex environments remains unclear. The recent development of new experimental models coupled with significant advances in cell imaging approaches have provided platforms for researchers to begin to dissect adhesion signalling in cells in 3D matrices. Here we summarise the recent insights in cell adhesion formation and regulation in 3D model systems and the imaging approaches used to analyse these events.
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Affiliation(s)
- Asier Jayo
- Randall Division of Cell and Molecular Biophysics, King's College London, Guys Campus, UK
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234
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Cavnar PJ, Mogen K, Berthier E, Beebe DJ, Huttenlocher A. The actin regulatory protein HS1 interacts with Arp2/3 and mediates efficient neutrophil chemotaxis. J Biol Chem 2012; 287:25466-77. [PMID: 22679023 DOI: 10.1074/jbc.m112.364562] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
HS1 is an actin regulatory protein and cortactin homolog that is expressed in hematopoietic cells. Antigen receptor stimulation induces HS1 phosphorylation, and HS1 is essential for T cell activation. HS1 is also expressed in neutrophils; however, the function of HS1 in neutrophils is not known. Here we show that HS1 localizes to the neutrophil leading edge, and is phosphorylated in response to the chemoattractant formyl-Met-Leu-Phe (fMLP) in adherent cells. Using live imaging in microchannels, we show that depletion of endogenous HS1 in the neutrophil-like PLB-985 cell line impairs chemotaxis. We also find that HS1 is necessary for chemoattractant-induced activation of Rac GTPase signaling and Vav1 phosphorylation, suggesting that HS1-mediated Rac activation is necessary for efficient neutrophil chemotaxis. We identify specific phosphorylation sites that mediate HS1-dependent neutrophil motility. Expression of HS1 Y378F, Y397F is sufficient to rescue migration of HS1-deficient neutrophils, however, a triple phospho-mutant Y222F, Y378F, Y397F did not rescue migration of HS1-deficient neutrophils. Moreover, HS1 phosphorylation on Y222, Y378, and Y397 regulates its interaction with Arp2/3. Collectively, our findings identify a novel role for HS1 and its phosphorylation during neutrophil directed migration.
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Affiliation(s)
- Peter J Cavnar
- Departments of Pediatrics and Medical Microbiology and Immunology, 4205 Microbial Sciences Building, University of Wisconsin-Madison, Madison, Wisconsin 53706, USA
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235
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Welf ES, Ahmed S, Johnson HE, Melvin AT, Haugh JM. Migrating fibroblasts reorient directionality by a metastable, PI3K-dependent mechanism. ACTA ACUST UNITED AC 2012; 197:105-14. [PMID: 22472441 PMCID: PMC3317800 DOI: 10.1083/jcb.201108152] [Citation(s) in RCA: 76] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Mesenchymal cell migration as exhibited by fibroblasts is distinct from amoeboid cell migration and is characterized by dynamic competition among multiple protrusions, which determines directional persistence and responses to spatial cues. Localization of phosphoinositide 3-kinase (PI3K) signaling is thought to play a broadly important role in cell motility, yet the context-dependent functions of this pathway have not been adequately elucidated. By mapping the spatiotemporal dynamics of cell protrusion/retraction and PI3K signaling monitored by total internal reflection fluorescence microscopy, we show that randomly migrating fibroblasts reorient polarity through PI3K-dependent branching and pivoting of protrusions. PI3K inhibition did not affect the initiation of newly branched protrusions, nor did it prevent protrusion induced by photoactivation of Rac. Rather, PI3K signaling increased after, not before, the onset of local protrusion and was required for the lateral spreading and stabilization of nascent branches. During chemotaxis, the branch experiencing the higher chemoattractant concentration was favored, and, thus, the cell reoriented so as to align with the external gradient.
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Affiliation(s)
- Erik S Welf
- Department of Chemical and Biomolecular Engineering, North Carolina State University, Raleigh, NC 27695, USA
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236
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Renshaw SA, Trede NS. A model 450 million years in the making: zebrafish and vertebrate immunity. Dis Model Mech 2012; 5:38-47. [PMID: 22228790 PMCID: PMC3255542 DOI: 10.1242/dmm.007138] [Citation(s) in RCA: 249] [Impact Index Per Article: 20.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
Since its first splash 30 years ago, the use of the zebrafish model has been extended from a tool for genetic dissection of early vertebrate development to the functional interrogation of organogenesis and disease processes such as infection and cancer. In particular, there is recent and growing attention in the scientific community directed at the immune systems of zebrafish. This development is based on the ability to image cell movements and organogenesis in an entire vertebrate organism, complemented by increasing recognition that zebrafish and vertebrate immunity have many aspects in common. Here, we review zebrafish immunity with a particular focus on recent studies that exploit the unique genetic and in vivo imaging advantages available for this organism. These unique advantages are driving forward our study of vertebrate immunity in general, with important consequences for the understanding of mammalian immune function and its role in disease pathogenesis.
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Affiliation(s)
- Stephen A Renshaw
- MRC Centre for Developmental and Biomedical Genetics, University of Sheffield, Western Bank, Sheffield, S10 2TN, UK.
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237
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Christie JM, Gawthorne J, Young G, Fraser NJ, Roe AJ. LOV to BLUF: flavoprotein contributions to the optogenetic toolkit. MOLECULAR PLANT 2012; 5:533-44. [PMID: 22431563 DOI: 10.1093/mp/sss020] [Citation(s) in RCA: 99] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/11/2023]
Abstract
Optogenetics is an emerging field that combines optical and genetic approaches to non-invasively interfere with cellular events with exquisite spatiotemporal control. Although it arose originally from neuroscience, optogenetics is widely applicable to the study of many different biological systems and the range of applications arising from this technology continues to increase. Moreover, the repertoire of light-sensitive proteins used for devising new optogenetic tools is rapidly expanding. Light, Oxygen, or Voltage sensing (LOV) and Blue-Light-Utilizing flavin adenine dinucleotide (FAD) (BLUF) domains represent new contributors to the optogenetic toolkit. These small (100-140-amino acids) flavoprotein modules are derived from plant and bacterial photoreceptors that respond to UV-A/blue light. In recent years, considerable progress has been made in uncovering the photoactivation mechanisms of both LOV and BLUF domains. This knowledge has been applied in the design of synthetic photoswitches and fluorescent reporters with applications in cell biology and biotechnology. In this review, we summarize the photochemical properties of LOV and BLUF photosensors and highlight some of the recent advances in how these flavoproteins are being employed to artificially regulate and image a variety of biological processes.
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Affiliation(s)
- John M Christie
- Institute of Molecular Cell and Systems Biology, College of Medical, Veterinary and Life Sciences, University of Glasgow, UK.
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238
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Lan CC, Blake D, Henry S, Love DR. Fluorescent Function-Spacer-Lipid Construct Labelling Allows for Real-Time in Vivo Imaging of Cell Migration and Behaviour in Zebrafish (Danio Rerio). J Fluoresc 2012; 22:1055-63. [DOI: 10.1007/s10895-012-1043-3] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2011] [Accepted: 03/07/2012] [Indexed: 11/28/2022]
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239
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Strickland D, Lin Y, Wagner E, Hope CM, Zayner J, Antoniou C, Sosnick TR, Weiss EL, Glotzer M. TULIPs: tunable, light-controlled interacting protein tags for cell biology. Nat Methods 2012; 9:379-84. [PMID: 22388287 PMCID: PMC3444151 DOI: 10.1038/nmeth.1904] [Citation(s) in RCA: 365] [Impact Index Per Article: 30.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2011] [Accepted: 01/19/2012] [Indexed: 12/23/2022]
Abstract
Naturally photoswitchable proteins offer a means of directly manipulating the formation of protein complexes that drive a diversity of cellular processes. We have developed tunable light-inducible dimerization tags (TULIPs) based on a synthetic interaction between the LOV2 domain of Avena sativa phototropin 1 (AsLOV2) and an engineered PDZ domain (ePDZ). TULIP tags can recruit proteins to diverse structures in living yeast and mammalian cells, either globally or with precise spatial control using a steerable laser. The equilibrium binding and kinetic parameters of the interaction are tunable by mutation, making TULIPs readily adaptable to signaling pathways with varying sensitivities and response times. We demonstrate the utility of TULIPs by conferring light sensitivity to functionally distinct components of the yeast mating pathway and by directing the site of cell polarization.
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Affiliation(s)
- Devin Strickland
- Department of Molecular Genetics and Cell Biology, The University of Chicago, Chicago, Illinois, USA
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240
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Marée AFM, Grieneisen VA, Edelstein-Keshet L. How cells integrate complex stimuli: the effect of feedback from phosphoinositides and cell shape on cell polarization and motility. PLoS Comput Biol 2012; 8:e1002402. [PMID: 22396633 PMCID: PMC3291540 DOI: 10.1371/journal.pcbi.1002402] [Citation(s) in RCA: 80] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2011] [Accepted: 01/07/2012] [Indexed: 12/03/2022] Open
Abstract
To regulate shape changes, motility and chemotaxis in eukaryotic cells, signal transduction pathways channel extracellular stimuli to the reorganization of the actin cytoskeleton. The complexity of such networks makes it difficult to understand the roles of individual components, let alone their interactions and multiple feedbacks within a given layer and between layers of signalling. Even more challenging is the question of if and how the shape of the cell affects and is affected by this internal spatiotemporal reorganization. Here we build on our previous 2D cell motility model where signalling from the Rho family GTPases (Cdc42, Rac, and Rho) was shown to organize the cell polarization, actin reorganization, shape change, and motility in simple gradients. We extend this work in two ways: First, we investigate the effects of the feedback between the phosphoinositides (PIs) , and Rho family GTPases. We show how that feedback increases heights and breadths of zones of Cdc42 activity, facilitating global communication between competing cell “fronts”. This hastens the commitment to a single lamellipodium initiated in response to multiple, complex, or rapidly changing stimuli. Second, we show how cell shape feeds back on internal distribution of GTPases. Constraints on chemical isocline curvature imposed by boundary conditions results in the fact that dynamic cell shape leads to faster biochemical redistribution when the cell is repolarized. Cells with frozen cytoskeleton, and static shapes, consequently respond more slowly to reorienting stimuli than cells with dynamic shape changes, the degree of the shape-induced effects being proportional to the extent of cell deformation. We explain these concepts in the context of several in silico experiments using our 2D computational cell model. Single cells, such as amoeba and white blood cells, change shape and move in response to environmental stimuli. Their behaviour is a consequence of the intracellular properties balanced by external forces. The internal regulation is modulated by several proteins that interact with one another and with membrane lipids. We examine, through in silico experiments using a computational model of a moving cell, the interactions of an important class of such proteins (Rho GTPases) and lipids (phosphoinositides, PIs), their spatial redistribution, and how they affect and are affected by cell shape. Certain GTPases promote the assembly of the actin cytoskeleton. This then leads to the formation of a cell protrusion, the leading edge. The feedback between PIs and GTPases facilitates global communication across the cell, ensuring that multiple, complex, or rapidly changing stimuli can be resolved into a single decision for positioning the leading edge. Interestingly, the cell shape itself affects the intracellular biochemistry, resulting from interactions between the curvature of the chemical fronts and the cell edge. Cells with static shapes consequently respond more slowly to reorienting stimuli than cells with dynamic shape changes. This potential to respond more rapidly to external stimuli depends on the degree of cellular shape deformation.
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Affiliation(s)
- Athanasius F M Marée
- Computational & Systems Biology, John Innes Centre, Norwich Research Park, Norwich, United Kingdom.
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241
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Timpson P, McGhee EJ, Anderson KI. Imaging molecular dynamics in vivo--from cell biology to animal models. J Cell Sci 2012; 124:2877-90. [PMID: 21878495 DOI: 10.1242/jcs.085191] [Citation(s) in RCA: 65] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
Advances in fluorescence microscopy have enabled the study of membrane diffusion, cell adhesion and signal transduction at the molecular level in living cells grown in culture. By contrast, imaging in living organisms has primarily been restricted to the localization and dynamics of cells in tissues. Now, imaging of molecular dynamics is on the cusp of progressing from cell culture to living tissue. This transition has been driven by the understanding that the microenvironment critically determines many developmental and pathological processes. Here, we review recent progress in fluorescent protein imaging in vivo by drawing primarily on cancer-related studies in mice. We emphasize the need for techniques that can be easily combined with genetic models and complement fluorescent protein imaging by providing contextual information about the cellular environment. In this Commentary we will consider differences between in vitro and in vivo experimental design and argue for an approach to in vivo imaging that is built upon the use of intermediate systems, such as 3-D and explant culture models, which offer flexibility and control that is not always available in vivo. Collectively, these methods present a paradigm shift towards the molecular-level investigation of disease and therapy in animal models of disease.
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Affiliation(s)
- Paul Timpson
- The Beatson Institute for Cancer Research, Garscube Estate, Glasgow G611BD, UK
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242
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Tibarewal P, Zilidis G, Spinelli L, Schurch N, Maccario H, Gray A, Perera NM, Davidson L, Barton GJ, Leslie NR. PTEN Protein Phosphatase Activity Correlates with Control of Gene Expression and Invasion, a Tumor-Suppressing Phenotype, But Not with AKT Activity. Sci Signal 2012; 5:ra18. [DOI: 10.1126/scisignal.2002138] [Citation(s) in RCA: 93] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
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243
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Effective guidance of collective migration based on differences in cell states. Proc Natl Acad Sci U S A 2012; 109:2027-32. [PMID: 22308382 DOI: 10.1073/pnas.1115260109] [Citation(s) in RCA: 53] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023] Open
Abstract
Directed cell migration is important for normal animal development and physiology. The process can also be subverted by tumor cells to invade other tissues and to metastasize. Some cells, such as leukocytes, migrate individually; other cells migrate together in groups or sheets, called collective cell migration. Guidance of individually migrating cells depends critically on subcellularly localized perception and transduction of signals. For collective cell migration, guidance could result from cells within a group achieving different signaling levels, with directionality then encoded in the collective rather than in individual cells. Here we subject this collective guidance hypothesis to direct tests, using migration of border cells during Drosophila oogenesis as our model system. These cells normally use two receptor tyrosine kinases (RTKs), PDGF/VEGF-related receptor (PVR) and EGFR, to read guidance cues secreted by the oocyte. Elevated but delocalized RTK signaling in one cell of the cluster was achieved by overexpression of PVR in the absence of ligand or by overexpression of fusion receptors unable to detect Drosophila ligands; alternatively, Rac was photoactivated centrally within a single cell. In each case, one cell within the group was in a high signal state, whereas others were in low signal states. The high signal cell directed cluster movement effectively. We conclude that differences in cell signaling states are sufficient to direct collective migration and are likely a substantial contributor to normal guidance. Cell signaling states could manifest as differences in gene expression or metabolite levels and thus differ substantially from factors normally considered when analyzing eukaryotic cell guidance.
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244
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Novoa B, Figueras A. Zebrafish: model for the study of inflammation and the innate immune response to infectious diseases. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2012; 946:253-75. [PMID: 21948373 DOI: 10.1007/978-1-4614-0106-3_15] [Citation(s) in RCA: 187] [Impact Index Per Article: 15.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
The zebrafish (Danio rerio) has been extensively used in biomedical research as a model to study vertebrate development and hematopoiesis and recently, it has been adopted into varied fields including immunology. After fertilization, larvae survive with only the innate immune responses because adaptive immune system is morphologically and functionally mature only after 4-6 weeks postfertilization. This temporal separation provides a suitable system to study the vertebrate innate immune response in vivo, independently from the adaptive immune response. The transparency of early life stages allows a useful real-time visualization. Adult zebrafish which have complete (innate and adaptative) immune systems offer also advantages over other vertebrate infection models: small size, relatively rapid life cycle, ease of breeding, and a growing list of molecular tools for the study of infectious diseases. In this review, we have tried to give some examples of the potential of zebrafish as a valuable model in innate immunity and inflammation studies.
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Affiliation(s)
- Beatriz Novoa
- Instituto de Investigaciones Marinas, CSIC, Eduardo Cabello 6, 36208 Vigo, Spain.
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245
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Deng Q, Harvie EA, Huttenlocher A. Distinct signalling mechanisms mediate neutrophil attraction to bacterial infection and tissue injury. Cell Microbiol 2012; 14:517-28. [PMID: 22188170 DOI: 10.1111/j.1462-5822.2011.01738.x] [Citation(s) in RCA: 57] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
The signals that guide neutrophils to sites of tissue injury or infection remain elusive. H(2)O(2) has been implicated in neutrophil sensing of tissue injury and transformed cells; however, its role in neutrophil recruitment to infection has not been explored. Here, using a pharmacological inhibitor of NADPH oxidases, diphenyleneiodonium (DPI), and genetic depletion of an epithelial-specific NADPH oxidase, we show that H(2)O(2) is not required for neutrophil detection of localized infection with the Gram-negative bacterium Pseudomonas aeruginosa. In contrast, PI3K signalling is required for neutrophil responses to both wounding and infection. In vivo imaging using a H(2)O(2) probe detects dynamic H(2)O(2) generation at wounds but not at infected tissue. Moreover, DPI no longer inhibits neutrophil wound attraction when P. aeruginosa is present in the media. Finally, DPI also fails to inhibit neutrophil recruitment to localized infection with the Gram-positive bacterium, Streptococcus iniae. Our findings demonstrate that different signals are involved in sensitizing neutrophils to pathogen versus non-pathogen induced tissue damage, providing a potential target to preferentially suppress non-specific immune damage without affecting the response to infection.
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Affiliation(s)
- Qing Deng
- Department of Medical Microbiology and Immunology, University of Wisconsin-Madison, Madison, WI 53706, USA.
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246
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Tucker CL. Manipulating cellular processes using optical control of protein-protein interactions. PROGRESS IN BRAIN RESEARCH 2012; 196:95-117. [PMID: 22341323 DOI: 10.1016/b978-0-444-59426-6.00006-9] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Tools for optical control of proteins offer an unprecedented level of spatiotemporal control over biological processes, adding a new layer of experimental opportunity. While use of light-activated cation channels and anion pumps has already revolutionized neurobiology, an emerging class of more general optogenetic tools may have similar transformative effects. These tools consist of light-dependent protein interaction modules that allow control of target protein interactions and localization with light. Such tools are modular and can be applied to regulate a wide variety of biological activities. This chapter reviews the different properties of light-induced dimerization systems, based on plant phytochromes, cryptochromes, and light-oxygen-voltage domain proteins, exploring advantages and limitations of the different systems and practical considerations related to their use. Potential applications of these tools within the neurobiology field, including light control of various signaling pathways, neuronal activity, and DNA recombination and transcription, are discussed.
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Affiliation(s)
- Chandra L Tucker
- Department of Pharmacology, University of Colorado School of Medicine, Aurora, CO, USA.
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247
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Abstract
Phosphatidylinositol lipids generated through the action of phosphinositide 3-kinase (PI3K) are key mediators of a wide array of biological responses. In particular, their role in the regulation of cell migration has been extensively studied and extends to amoeboid as well as mesenchymal migration. Through the emergence of fluorescent probes that target PI3K products as well as the use of specific inhibitors and knockout technologies, the spatio-temporal distribution of PI3K products in chemotaxing cells has been shown to represent a key anterior polarity signal that targets downstream effectors to actin polymerization. In addition, through intricate cross-talk networks PI3K products have been shown to regulate signals that control posterior effectors. Yet, in more complex environments or in conditions where chemoattractant gradients are steep, a variety of cell types can still chemotax in the absence of PI3K signals. Indeed, parallel signal transduction pathways have been shown to coordinately regulate cell polarity and directed movement. In this chapter, we will review the current role PI3K products play in the regulation of directed cell migration in various cell types, highlight the importance of mathematical modeling in the study of chemotaxis, and end with a brief overview of other signaling cascades known to also regulate chemotaxis.
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Affiliation(s)
- Michael C Weiger
- Laboratory of Cellular and Molecular Biology, National Cancer Institute, National Institutes of Health, 37 Convent Drive, Bldg.37/Rm2066, 20892-4256, Bethesda, MD, USA
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248
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Wernimont SA, Wiemer AJ, Bennin DA, Monkley SJ, Ludwig T, Critchley DR, Huttenlocher A. Contact-dependent T cell activation and T cell stopping require talin1. JOURNAL OF IMMUNOLOGY (BALTIMORE, MD. : 1950) 2011; 187:6256-67. [PMID: 22075696 PMCID: PMC3237745 DOI: 10.4049/jimmunol.1102028] [Citation(s) in RCA: 56] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
T cell-APC contact initiates T cell activation and is maintained by the integrin LFA-1. Talin1, an LFA-1 regulator, localizes to the immune synapse (IS) with unknown roles in T cell activation. In this study, we show that talin1-deficient T cells have defects in contact-dependent T cell stopping and proliferation. Although talin1-deficient T cells did not form stable interactions with APCs, transient contacts were sufficient to induce signaling. In contrast to prior models, LFA-1 polarized to T cell-APC contacts in talin1-deficient T cells, but vinculin and F-actin polarization at the IS was impaired. These results indicate that T cell proliferation requires sustained, talin1-mediated T cell-APC interactions and that talin1 is necessary for F-actin polarization and the stability of the IS.
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Affiliation(s)
- Sarah A Wernimont
- Program in Cellular and Molecular Biology, University of Wisconsin, Madison WI 53705
| | - Andrew J Wiemer
- Department of Pediatrics and Medical Microbiology and Immunology, University of Wisconsin, Madison WI 53706
- Institute on Aging, University of Wisconsin-Madison, Madison WI 53706
| | - David A Bennin
- Department of Pediatrics and Medical Microbiology and Immunology, University of Wisconsin, Madison WI 53706
| | - Susan J Monkley
- Department of Biochemistry, University of Leicester, Leicester LE1 9HN, UK
| | - Thomas Ludwig
- Institute for Cancer Genetics, Columbia University, New York, NY 10032
| | - David R Critchley
- Department of Biochemistry, University of Leicester, Leicester LE1 9HN, UK
| | - Anna Huttenlocher
- Department of Pediatrics and Medical Microbiology and Immunology, University of Wisconsin, Madison WI 53706
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249
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Sandquist JC, Kita AM, Bement WM. And the dead shall rise: actin and myosin return to the spindle. Dev Cell 2011; 21:410-9. [PMID: 21920311 DOI: 10.1016/j.devcel.2011.07.018] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2011] [Revised: 07/27/2011] [Accepted: 07/29/2011] [Indexed: 10/17/2022]
Abstract
The spindle directs chromosome partitioning in eukaryotes and, for the last three decades, has been considered primarily a structure based on microtubules, microtubule motors, and other microtubule binding proteins. However, a surprisingly large body of both old and new studies suggests roles for actin filaments (F-actin) and myosins (F-actin-based motor proteins) in spindle assembly and function. Here we review these data and conclude that in several cases the evidence for the participation of F-actin and myosins in spindle function is very strong, and in the situations where it is less strong, there is nevertheless enough evidence to warrant further investigation.
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Affiliation(s)
- Joshua C Sandquist
- Department of Zoology, University of Wisconsin-Madison, Madison, WI 53706, USA.
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250
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Yoo SK, Starnes TW, Deng Q, Huttenlocher A. Lyn is a redox sensor that mediates leukocyte wound attraction in vivo. Nature 2011; 480:109-12. [PMID: 22101434 PMCID: PMC3228893 DOI: 10.1038/nature10632] [Citation(s) in RCA: 319] [Impact Index Per Article: 24.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2011] [Accepted: 10/14/2011] [Indexed: 12/22/2022]
Abstract
Tissue wounding induces the rapid recruitment of leukocytes. Wounds and tumours--a type of 'unhealed wound'--generate hydrogen peroxide (H(2)O(2)) through an NADPH oxidase (NOX). This extracellular H(2)O(2) mediates recruitment of leukocytes, particularly the first responders of innate immunity, neutrophils, to injured tissue. However, the sensor that neutrophils use to detect the redox state at wounds is unknown. Here we identify the Src family kinase (SFK) Lyn as a redox sensor that mediates initial neutrophil recruitment to wounds in zebrafish larvae. Lyn activation in neutrophils is dependent on wound-derived H(2)O(2) after tissue injury, and inhibition of Lyn attenuates neutrophil wound recruitment. Inhibition of SFKs also disrupted H(2)O(2)-mediated chemotaxis of primary human neutrophils. In vitro analysis identified a single cysteine residue, C466, as being responsible for direct oxidation-mediated activation of Lyn. Furthermore, transgenic-tissue-specific reconstitution with wild-type Lyn and a cysteine mutant revealed that Lyn C466 is important for the neutrophil wound response and downstream signalling in vivo. This is the first identification, to our knowledge, of a physiological redox sensor that mediates leukocyte wound attraction in multicellular organisms.
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Affiliation(s)
- Sa Kan Yoo
- Program in Cellular and Molecular Biology, University of Wisconsin-Madison, Madison, Wisconsin 53706, USA
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