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Eigenschink M, Wessely I, Dijmarescu M, Förster-Waldl E, Farr A, Kiss H, Berger A, Wisgrill L. Transcriptomic analysis identifies lactoferrin-induced quiescent circuits in neonatal macrophages. Front Immunol 2023; 14:1276173. [PMID: 37868991 PMCID: PMC10590118 DOI: 10.3389/fimmu.2023.1276173] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2023] [Accepted: 09/18/2023] [Indexed: 10/24/2023] Open
Abstract
Introduction Upon birth, a hitherto naïve immune system is confronted with a plethora of microbial antigens due to intestinal bacterial colonization. To prevent excessive inflammation and disruption of the epithelial barrier, physiological mechanisms must promote immune-anergy within the neonatal gut. As high concentrations of human lactoferrin (hLF), a transferrin glycoprotein shown to modulate macrophage function, are frequently encountered in colostrum, its direct interaction with intestinal macrophages may satisfy this physiological need. Thus, the primary objective of this study was to investigate transcriptional changes induced by human lactoferrin in neonatal monocyte-derived macrophages. Methods Cord blood-derived monocytes were differentiated with M-CSF in presence or absence of 500 µg/mL hLF for 7 days and afterwards stimulated with 1 ng/mL LPS or left untreated. RNA was then isolated and subjected to microarray analysis. Results Differentiation of cord blood-derived monocytes in presence of hLF induced a distinct transcriptional program defined by cell cycle arrest in the G2/M phase, induction of IL-4/IL-13-like signaling, altered extracellular matrix interaction, and enhanced propensity for cell-cell interaction. Moreover, near-complete abrogation of transcriptional changes induced by TLR4 engagement with LPS was observed in hLF-treated samples. Discussion The global transition towards an M2-like homeostatic phenotype and the acquisition of quiescence elegantly demonstrate the ontogenetical relevance of hLF in attenuating pro-inflammatory signaling within the developing neonatal intestine. The marked anergy towards proinflammatory stimuli such as LPS further underlines the glycoprotein's potential therapeutic relevance.
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Affiliation(s)
- Michael Eigenschink
- Division of Neonatology, Pediatric Intensive Care and Neuropaediatrics, Department of Pediatrics and Adolescent Medicine, Comprehensive Center for Pediatrics, Medical University of Vienna, Vienna, Austria
| | - Isabelle Wessely
- Division of Neonatology, Pediatric Intensive Care and Neuropaediatrics, Department of Pediatrics and Adolescent Medicine, Comprehensive Center for Pediatrics, Medical University of Vienna, Vienna, Austria
| | - Marco Dijmarescu
- Division of Neonatology, Pediatric Intensive Care and Neuropaediatrics, Department of Pediatrics and Adolescent Medicine, Comprehensive Center for Pediatrics, Medical University of Vienna, Vienna, Austria
| | - Elisabeth Förster-Waldl
- Division of Neonatology, Pediatric Intensive Care and Neuropaediatrics, Department of Pediatrics and Adolescent Medicine, Comprehensive Center for Pediatrics, Medical University of Vienna, Vienna, Austria
| | - Alex Farr
- Department of Obstetrics and Gynecology, Division of Obstetrics and Feto-Maternal Medicine, Comprehensive Center for Pediatrics, Medical University of Vienna, Vienna, Austria
| | - Herbert Kiss
- Department of Obstetrics and Gynecology, Division of Obstetrics and Feto-Maternal Medicine, Comprehensive Center for Pediatrics, Medical University of Vienna, Vienna, Austria
| | - Angelika Berger
- Division of Neonatology, Pediatric Intensive Care and Neuropaediatrics, Department of Pediatrics and Adolescent Medicine, Comprehensive Center for Pediatrics, Medical University of Vienna, Vienna, Austria
| | - Lukas Wisgrill
- Division of Neonatology, Pediatric Intensive Care and Neuropaediatrics, Department of Pediatrics and Adolescent Medicine, Comprehensive Center for Pediatrics, Medical University of Vienna, Vienna, Austria
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2
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Zhan Y, Zhao CS, Qu X, Xiao Z, Deng C, Li Y. Identification of a novel amphioxus leucine-rich repeat receptor involved in phagocytosis reveals a role for Slit2-N-type LRR in bacterial elimination. J Biol Chem 2023; 299:104689. [PMID: 37044216 DOI: 10.1016/j.jbc.2023.104689] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2022] [Revised: 03/25/2023] [Accepted: 03/31/2023] [Indexed: 04/14/2023] Open
Abstract
The basal chordate amphioxus is a model for tracing the origin and evolution of vertebrate immunity. To explore the evolution of immunoreceptor signaling pathways, we searched the associated receptors of the amphioxus B. belcheri (Bb) homolog of immunoreceptor signaling adaptor protein Grb2. Mass-spectrum analysis of BbGrb2 immunoprecipitates from B. belcheri intestine lysates revealed a folate receptor (FR) domain- and leucine-rich repeat (LRR)-containing protein (FrLRR). Sequence and structural analysis showed that FrLRR is a membrane protein with a predicted curved solenoid structure. The N-terminal Fr domain contains very few folate-binding sites; the following LRR region is a Slit2-type LRR, and a GPI-anchored site was predicted at the C-terminus. RT-PCR analysis showed FrLRR is a transcription-mediated fusion gene of BbFR-like and BbSlit2-N-like genes. Genomic DNA structure analysis implied the B. belcheri FrLRR gene locus and the corresponding locus in B. floridae might be generated by exon shuffling of a Slit2-N-like gene into an FR gene. RT-qPCR, immunostaining and immunoblot results showed that FrLRR was primarily distributed in B. belcheri intestinal tissue. We further demonstrated that FrLRR localized to the cell membrane and lysosomes. Functionally, FrLRR mediated and promoted bacteria-binding and phagocytosis, and FrLRR antibody blocking or Grb2 knockdown inhibited FrLRR-mediated phagocytosis. Interestingly, we found that human Slit2-N (hSlit2-N) also mediated direct bacteria-binding and phagocytosis which was inhibited by Slit2-N antibody blocking or Grb2 knockdown. Together, these results indicate FrLRR and hSlit2-N may function as phagocytotic-receptors to promote phagocytosis through Grb2, implying the Slit2-N-type-LRR-containing proteins play a role in bacterial binding and elimination.
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Affiliation(s)
- Yanli Zhan
- MOE Key Laboratory of Gene Function and Regulation, Guangdong Province Key Laboratory of Pharmaceutical Functional Genes, State Key Laboratory of Biocontrol, School of Life Sciences, Sun Yat-sen University, Guangzhou 510275, China
| | - Chen-Si Zhao
- MOE Key Laboratory of Gene Function and Regulation, Guangdong Province Key Laboratory of Pharmaceutical Functional Genes, State Key Laboratory of Biocontrol, School of Life Sciences, Sun Yat-sen University, Guangzhou 510275, China
| | - Xuemei Qu
- MOE Key Laboratory of Gene Function and Regulation, Guangdong Province Key Laboratory of Pharmaceutical Functional Genes, State Key Laboratory of Biocontrol, School of Life Sciences, Sun Yat-sen University, Guangzhou 510275, China
| | - Zhihui Xiao
- MOE Key Laboratory of Gene Function and Regulation, Guangdong Province Key Laboratory of Pharmaceutical Functional Genes, State Key Laboratory of Biocontrol, School of Life Sciences, Sun Yat-sen University, Guangzhou 510275, China
| | - Chong Deng
- MOE Key Laboratory of Gene Function and Regulation, Guangdong Province Key Laboratory of Pharmaceutical Functional Genes, State Key Laboratory of Biocontrol, School of Life Sciences, Sun Yat-sen University, Guangzhou 510275, China
| | - Yingqiu Li
- MOE Key Laboratory of Gene Function and Regulation, Guangdong Province Key Laboratory of Pharmaceutical Functional Genes, State Key Laboratory of Biocontrol, School of Life Sciences, Sun Yat-sen University, Guangzhou 510275, China.
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3
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Lalnunthangi A, Dakpa G, Tiwari S. Multifunctional role of the ubiquitin proteasome pathway in phagocytosis. PROGRESS IN MOLECULAR BIOLOGY AND TRANSLATIONAL SCIENCE 2023; 194:179-217. [PMID: 36631192 DOI: 10.1016/bs.pmbts.2022.06.023] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/14/2023]
Abstract
Phagocytosis is a specialized form of endocytosis where large cells and particles (>0.5μm) are engulfed by the phagocytic cells, and ultimately digested in the phagolysosomes. This process not only eliminates unwanted particles and pathogens from the extracellular sources, but also eliminates apoptotic cells within the body, and is critical for maintenance of tissue homeostasis. It is believed that both endocytosis and phagocytosis share common pathways after particle internalization, but specialized features and differences between these two routes of internalization are also likely. The recruitment and removal of each protein/particle during the maturation of endocytic/phagocytic vesicles has to be tightly regulated to ensure their timely action. Ubiquitin proteasome pathway (UPP), degrades unwanted proteins by post-translational modification of proteins with chains of conserved protein Ubiquitin (Ub), with subsequent recognition of Ub chains by the 26S proteasomes and substrate degradation by this protease. This pathway utilizes different Ub linkages to modify proteins to regulate protein-protein interaction, localization, and activity. Due to its vast number of targets, it is involved in many cellular pathways, including phagocytosis. This chapters describes the basic steps and signaling in phagocytosis and different roles that UPP plays at multiple steps in regulating phagocytosis directly, or through its interaction with other phagosomal proteins. How aberrations in UPP function affect phagocytosis and their association with human diseases, and how pathogens exploit this pathway for their own benefit is also discussed.
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Affiliation(s)
| | | | - Swati Tiwari
- School of Biotechnology, Jawaharlal Nehru University, New Delhi, India.
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4
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Green ID, Pinello N, Song R, Lee Q, Halstead JM, Kwok CT, Wong ACH, Nair SS, Clark SJ, Roediger B, Schmitz U, Larance M, Hayashi R, Rasko JEJ, Wong JJL. Macrophage development and activation involve coordinated intron retention in key inflammatory regulators. Nucleic Acids Res 2020; 48:6513-6529. [PMID: 32449925 PMCID: PMC7337907 DOI: 10.1093/nar/gkaa435] [Citation(s) in RCA: 39] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2020] [Revised: 05/04/2020] [Accepted: 05/11/2020] [Indexed: 12/31/2022] Open
Abstract
Monocytes and macrophages are essential components of the innate immune system. Herein, we report that intron retention (IR) plays an important role in the development and function of these cells. Using Illumina mRNA sequencing, Nanopore direct cDNA sequencing and proteomics analysis, we identify IR events that affect the expression of key genes/proteins involved in macrophage development and function. We demonstrate that decreased IR in nuclear-detained mRNA is coupled with increased expression of genes encoding regulators of macrophage transcription, phagocytosis and inflammatory signalling, including ID2, IRF7, ENG and LAT. We further show that this dynamic IR program persists during the polarisation of resting macrophages into activated macrophages. In the presence of proinflammatory stimuli, intron-retaining CXCL2 and NFKBIZ transcripts are rapidly spliced, enabling timely expression of these key inflammatory regulators by macrophages. Our study provides novel insights into the molecular factors controlling vital regulators of the innate immune response.
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Affiliation(s)
- Immanuel D Green
- Epigenetics and RNA Biology Program Centenary Institute, The University of Sydney, Camperdown 2050, Australia.,Faculty of Medicine and Health, The University of Sydney, Camperdown 2050, Australia
| | - Natalia Pinello
- Epigenetics and RNA Biology Program Centenary Institute, The University of Sydney, Camperdown 2050, Australia.,Faculty of Medicine and Health, The University of Sydney, Camperdown 2050, Australia
| | - Renhua Song
- Epigenetics and RNA Biology Program Centenary Institute, The University of Sydney, Camperdown 2050, Australia.,Faculty of Medicine and Health, The University of Sydney, Camperdown 2050, Australia
| | - Quintin Lee
- Epigenetics and RNA Biology Program Centenary Institute, The University of Sydney, Camperdown 2050, Australia.,Faculty of Medicine and Health, The University of Sydney, Camperdown 2050, Australia.,Immune Imaging Program Centenary Institute, The University of Sydney, Camperdown 2050, Australia
| | - James M Halstead
- Epigenetics and RNA Biology Program Centenary Institute, The University of Sydney, Camperdown 2050, Australia.,Faculty of Medicine and Health, The University of Sydney, Camperdown 2050, Australia
| | - Chau-To Kwok
- Epigenetics and RNA Biology Program Centenary Institute, The University of Sydney, Camperdown 2050, Australia.,Faculty of Medicine and Health, The University of Sydney, Camperdown 2050, Australia
| | - Alex C H Wong
- Epigenetics and RNA Biology Program Centenary Institute, The University of Sydney, Camperdown 2050, Australia.,Faculty of Medicine and Health, The University of Sydney, Camperdown 2050, Australia.,Gene and Stem Cell Therapy Program Centenary Institute, The University of Sydney, Camperdown 2050, Australia
| | - Shalima S Nair
- Genomics and Epigenetics Division, Garvan Institute of Medical Research, Darlinghurst 2010, Australia.,St. Vincent's Clinical School, UNSW, Sydney 2010, Australia.,Kinghorn Centre for Clinical Genomics, Garvan Institute of Medical Research, Darlinghurst 2010, Australia
| | - Susan J Clark
- Genomics and Epigenetics Division, Garvan Institute of Medical Research, Darlinghurst 2010, Australia.,St. Vincent's Clinical School, UNSW, Sydney 2010, Australia
| | - Ben Roediger
- Faculty of Medicine and Health, The University of Sydney, Camperdown 2050, Australia.,Immune Imaging Program Centenary Institute, The University of Sydney, Camperdown 2050, Australia
| | - Ulf Schmitz
- Faculty of Medicine and Health, The University of Sydney, Camperdown 2050, Australia.,Gene and Stem Cell Therapy Program Centenary Institute, The University of Sydney, Camperdown 2050, Australia.,Computational Biomedicine Laboratory Centenary Institute, The University of Sydney, Camperdown 2050, Australia
| | - Mark Larance
- Charles Perkins Centre, School of Life and Environmental Sciences, University of Sydney, Camperdown 2006, New South Wales, Australia
| | - Rippei Hayashi
- The John Curtin School of Medical Research, The Australian National University, ACT 2601, Australia
| | - John E J Rasko
- Faculty of Medicine and Health, The University of Sydney, Camperdown 2050, Australia.,Gene and Stem Cell Therapy Program Centenary Institute, The University of Sydney, Camperdown 2050, Australia.,Cell and Molecular Therapies, Royal Prince Alfred Hospital, Camperdown 2050, Australia
| | - Justin J-L Wong
- Epigenetics and RNA Biology Program Centenary Institute, The University of Sydney, Camperdown 2050, Australia.,Faculty of Medicine and Health, The University of Sydney, Camperdown 2050, Australia
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5
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Uribe-Querol E, Rosales C. Phagocytosis: Our Current Understanding of a Universal Biological Process. Front Immunol 2020; 11:1066. [PMID: 32582172 PMCID: PMC7280488 DOI: 10.3389/fimmu.2020.01066] [Citation(s) in RCA: 264] [Impact Index Per Article: 66.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2020] [Accepted: 05/04/2020] [Indexed: 12/22/2022] Open
Abstract
Phagocytosis is a cellular process for ingesting and eliminating particles larger than 0.5 μm in diameter, including microorganisms, foreign substances, and apoptotic cells. Phagocytosis is found in many types of cells and it is, in consequence an essential process for tissue homeostasis. However, only specialized cells termed professional phagocytes accomplish phagocytosis with high efficiency. Macrophages, neutrophils, monocytes, dendritic cells, and osteoclasts are among these dedicated cells. These professional phagocytes express several phagocytic receptors that activate signaling pathways resulting in phagocytosis. The process of phagocytosis involves several phases: i) detection of the particle to be ingested, ii) activation of the internalization process, iii) formation of a specialized vacuole called phagosome, and iv) maturation of the phagosome to transform it into a phagolysosome. In this review, we present a general view of our current understanding on cells, phagocytic receptors and phases involved in phagocytosis.
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Affiliation(s)
- Eileen Uribe-Querol
- División de Estudios de Posgrado e Investigación, Facultad de Odontología, Universidad Nacional Autónoma de México, Mexico City, Mexico
| | - Carlos Rosales
- Departamento de Inmunología, Instituto de Investigaciones Biomédicas, Universidad Nacional Autónoma de México, Mexico City, Mexico
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6
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Walpole GFW, Grinstein S. Endocytosis and the internalization of pathogenic organisms: focus on phosphoinositides. F1000Res 2020; 9. [PMID: 32494357 PMCID: PMC7233180 DOI: 10.12688/f1000research.22393.1] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 05/07/2020] [Indexed: 12/18/2022] Open
Abstract
Despite their comparatively low abundance in biological membranes, phosphoinositides are key to the regulation of a diverse array of signaling pathways and direct membrane traffic. The role of phosphoinositides in the initiation and progression of endocytic pathways has been studied in considerable depth. Recent advances have revealed that distinct phosphoinositide species feature prominently in clathrin-dependent and -independent endocytosis as well as in phagocytosis and macropinocytosis. Moreover, a variety of intracellular and cell-associated pathogens have developed strategies to commandeer host cell phosphoinositide metabolism to gain entry and/or metabolic advantage, thereby promoting their survival and proliferation. Here, we briefly survey the current knowledge on the involvement of phosphoinositides in endocytosis, phagocytosis, and macropinocytosis and highlight several examples of molecular mimicry employed by pathogens to either “hitch a ride” on endocytic pathways endogenous to the host or create an entry path of their own.
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Affiliation(s)
- Glenn F W Walpole
- Program in Cell Biology, Hospital for Sick Children, Toronto, ON, Canada.,Department of Biochemistry, University of Toronto, Toronto, ON, Canada
| | - Sergio Grinstein
- Program in Cell Biology, Hospital for Sick Children, Toronto, ON, Canada.,Department of Biochemistry, University of Toronto, Toronto, ON, Canada.,Keenan Research Centre of the Li Ka Shing Knowledge Institute, St. Michael's Hospital, Toronto, ON, Canada
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7
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Curson JEB, Luo L, Sweet MJ, Stow JL. pTRAPs: Transmembrane adaptors in innate immune signaling. J Leukoc Biol 2018; 103:1011-1019. [PMID: 29601097 DOI: 10.1002/jlb.2ri1117-474r] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2017] [Revised: 02/08/2018] [Accepted: 02/10/2018] [Indexed: 01/30/2023] Open
Abstract
Transmembrane adaptor proteins (TRAPs) are protein scaffolds and signaling regulators with established roles in signal-induced activation of lymphocytes. A subset of the TRAP family, the palmitoylated TRAPs (pTRAPs), are increasingly emerging with additional roles in innate immune cells. Targeted to lipid rafts, tetraspannin-enriched microdomains, and protein microclusters in membranes, pTRAP scaffolds exert spatiotemporal regulation by recruiting signaling kinases, particularly Src and Syk family members, as well as Csk, and other effectors. In this way, pTRAPs modulate signaling and influence resulting cell responses, including the selective output of inflammatory cytokines and other mediators. Here, we review studies revealing that different pTRAPs work together, often with overlapping or redundant roles, for positive and negative regulation of key innate immune pathways, including Fc receptor and pattern recognition receptor signaling. Recent findings show that pTRAPs can bind directly to innate immune receptors, in addition to other transmembrane binding partners. Thus, pTRAPs are important, multifunctional scaffolds in pathways that are fundamental to diverse innate immune responses.
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Affiliation(s)
- James E B Curson
- Institute for Molecular Bioscience (IMB), IMB Centre for Inflammation and Disease Research and Australian Infectious Diseases Research Centre, The University of Queensland, Brisbane, Queensland, Australia
| | - Lin Luo
- Institute for Molecular Bioscience (IMB), IMB Centre for Inflammation and Disease Research and Australian Infectious Diseases Research Centre, The University of Queensland, Brisbane, Queensland, Australia
| | - Matthew J Sweet
- Institute for Molecular Bioscience (IMB), IMB Centre for Inflammation and Disease Research and Australian Infectious Diseases Research Centre, The University of Queensland, Brisbane, Queensland, Australia
| | - Jennifer L Stow
- Institute for Molecular Bioscience (IMB), IMB Centre for Inflammation and Disease Research and Australian Infectious Diseases Research Centre, The University of Queensland, Brisbane, Queensland, Australia
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8
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Syk-dependent tyrosine phosphorylation of 3BP2 is required for optimal FcRγ-mediated phagocytosis and chemokine expression in U937 cells. Sci Rep 2017; 7:11480. [PMID: 28904407 PMCID: PMC5597638 DOI: 10.1038/s41598-017-11915-5] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2017] [Accepted: 08/31/2017] [Indexed: 11/24/2022] Open
Abstract
The adaptor protein c-Abl SH3 domain binding protein-2 (3BP2) is tyrosine phosphorylated by Syk in response to cross-linking of antigen receptors, which in turn activates various immune responses. Recently, a study using the mouse model of cherubism, a dominant inherited disorder caused by mutations in the gene encoding 3BP2, showed that 3BP2 is involved in the regulation of phagocytosis mediated by Fc receptor for IgG (FcγR) in macrophages. However, the molecular mechanisms underlying 3BP2-mediated regulation of phagocytosis and the physiological relevance of 3BP2 tyrosine phosphorylation remains elusive. In this study, we established various gene knockout U937 cell lines using the CRISPR/Cas9 system and found that 3BP2 is rapidly tyrosine phosphorylated by Syk in response to cross-linking of FcγRI. Depletion of 3BP2 caused significant reduction in the Fc receptor γ chain (FcRγ)-mediated phagocytosis in addition to the FcγRI-mediated induction of chemokine mRNA for IL-8, CCL3L3 and CCL4L2. Syk-dependent tyrosine phosphorylation of 3BP2 was required for overcoming these defects. Finally, we found that the PH and SH2 domains play important roles on FcγRI-mediated tyrosine phosphorylation of 3BP2 in HL-60 cells. Taken together, these results indicate that Syk-dependent tyrosine phosphorylation of 3BP2 is required for optimal FcRγ-mediated phagocytosis and chemokine expression.
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9
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Levin R, Grinstein S, Canton J. The life cycle of phagosomes: formation, maturation, and resolution. Immunol Rev 2017; 273:156-79. [PMID: 27558334 DOI: 10.1111/imr.12439] [Citation(s) in RCA: 189] [Impact Index Per Article: 27.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
Phagocytosis, the regulated uptake of large particles (>0.5 μm in diameter), is essential for tissue homeostasis and is also an early, critical component of the innate immune response. Phagocytosis can be conceptually divided into three stages: phagosome, formation, maturation, and resolution. Each of these involves multiple reactions that require exquisite spatial and temporal orchestration. The molecular events underlying these stages are being unraveled and the current state of knowledge is briefly summarized in this article.
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Affiliation(s)
- Roni Levin
- Program in Cell Biology, Hospital for Sick Children, Toronto, ON, Canada.,Department of Biochemistry, University of Toronto, Toronto, ON, Canada
| | - Sergio Grinstein
- Program in Cell Biology, Hospital for Sick Children, Toronto, ON, Canada.,Department of Biochemistry, University of Toronto, Toronto, ON, Canada.,Keenan Research Centre of the Li Ka Shing Knowledge Institute, St. Michael's Hospital, Toronto, ON, Canada
| | - Johnathan Canton
- Program in Cell Biology, Hospital for Sick Children, Toronto, ON, Canada
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10
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Abstract
Phagocytosis refers to the active process that allows cells to take up large particulate material upon binding to surface receptors. The discovery of phagocytosis in 1883 by Elie Metchnikoff, leading to the concept that specialized cells are implicated in the defense against microbes, was one of the starting points of the field of immunology. After more than a century of research, phagocytosis is now appreciated to be a widely used process that enables the cellular uptake of a remarkable variety of particles, including bacteria, fungi, parasites, viruses, dead cells, and assorted debris and solid materials. Uptake of foreign particles is performed almost exclusively by specialized myeloid cells, commonly termed "professional phagocytes": neutrophils, monocytes, macrophages, and dendritic cells. Phagocytosis of microbes not only stops or at least restricts the spread of infection but also plays an important role in regulating the innate and adaptive immune responses. Activation of the myeloid cells upon phagocytosis leads to the secretion of cytokines and chemokines that convey signals to a variety of immune cells. Moreover, foreign antigens generated by the degradation of microbes following phagocytosis are loaded onto the major histocompatibility complex for presentation to specific T lymphocytes. However, phagocytosis is not restricted to professional myeloid phagocytes; an expanding diversity of cell types appear capable of engulfing apoptotic bodies and debris, playing a critical role in tissue remodeling and in the clearance of billions of effete cells every day.
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11
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Levin R, Grinstein S, Schlam D. Phosphoinositides in phagocytosis and macropinocytosis. Biochim Biophys Acta Mol Cell Biol Lipids 2014; 1851:805-23. [PMID: 25238964 DOI: 10.1016/j.bbalip.2014.09.005] [Citation(s) in RCA: 104] [Impact Index Per Article: 10.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2014] [Revised: 08/23/2014] [Accepted: 09/08/2014] [Indexed: 01/08/2023]
Abstract
Professional phagocytes provide immunoprotection and aid in the maintenance of tissue homeostasis. They perform these tasks by recognizing, engulfing and eliminating pathogens and endogenous cell debris. Here, we examine the paramount role played by phosphoinositides in phagocytosis and macropinocytosis, two major endocytic routes that mediate the uptake of particulate and fluid matter, respectively. We analyze accumulating literature describing the molecular mechanisms whereby phosphoinositides translate environmental cues into the complex, sophisticated responses that underlie the phagocytic and macropinocytic responses. In addition, we exemplify virulence strategies involving modulation of host cell phosphoinositide signaling that are employed by bacteria to undermine immunity. This article is part of a Special Issue entitled Phosphoinositides.
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Affiliation(s)
- Roni Levin
- Division of Cell Biology, Hospital for Sick Children, 555 University Ave., Toronto M5G1X8, Canada
| | - Sergio Grinstein
- Division of Cell Biology, Hospital for Sick Children, 555 University Ave., Toronto M5G1X8, Canada; Keenan Research Centre of the Li Ka Shing Knowledge Institute, St. Michael's Hospital, 209 Victoria St., Toronto M5C1N8, Canada.
| | - Daniel Schlam
- Division of Cell Biology, Hospital for Sick Children, 555 University Ave., Toronto M5G1X8, Canada
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12
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Hu X, Liou AKF, Leak RK, Xu M, An C, Suenaga J, Shi Y, Gao Y, Zheng P, Chen J. Neurobiology of microglial action in CNS injuries: receptor-mediated signaling mechanisms and functional roles. Prog Neurobiol 2014; 119-120:60-84. [PMID: 24923657 PMCID: PMC4121732 DOI: 10.1016/j.pneurobio.2014.06.002] [Citation(s) in RCA: 110] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2014] [Revised: 05/31/2014] [Accepted: 06/03/2014] [Indexed: 12/28/2022]
Abstract
Microglia are the first line of immune defense against central nervous system (CNS) injuries and disorders. These highly plastic cells play dualistic roles in neuronal injury and recovery and are known for their ability to assume diverse phenotypes. A broad range of surface receptors are expressed on microglia and mediate microglial 'On' or 'Off' responses to signals from other host cells as well as invading microorganisms. The integrated actions of these receptors result in tightly regulated biological functions, including cell mobility, phagocytosis, the induction of acquired immunity, and trophic factor/inflammatory mediator release. Over the last few years, significant advances have been made toward deciphering the signaling mechanisms related to these receptors and their specific cellular functions. In this review, we describe the current state of knowledge of the surface receptors involved in microglial activation, with an emphasis on their engagement of distinct functional programs and their roles in CNS injuries. It will become evident from this review that microglial homeostasis is carefully maintained by multiple counterbalanced strategies, including, but not limited to, 'On' and 'Off' receptor signaling. Specific regulation of theses microglial receptors may be a promising therapeutic strategy against CNS injuries.
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Affiliation(s)
- Xiaoming Hu
- Center of Cerebrovascular Disease Research, University of Pittsburgh School of Medicine, Pittsburgh, PA 15213, USA; State Key Laboratory of Medical Neurobiology and Institute of Brain Sciences, Fudan University, Shanghai, China; Geriatric Research, Educational and Clinical Center, Veterans Affairs Pittsburgh Health Care System, Pittsburgh, PA 15240, USA.
| | - Anthony K F Liou
- Center of Cerebrovascular Disease Research, University of Pittsburgh School of Medicine, Pittsburgh, PA 15213, USA
| | - Rehana K Leak
- Division of Pharmaceutical Sciences, Duquesne University, Pittsburgh, PA 15282, USA
| | - Mingyue Xu
- State Key Laboratory of Medical Neurobiology and Institute of Brain Sciences, Fudan University, Shanghai, China
| | - Chengrui An
- State Key Laboratory of Medical Neurobiology and Institute of Brain Sciences, Fudan University, Shanghai, China
| | - Jun Suenaga
- Center of Cerebrovascular Disease Research, University of Pittsburgh School of Medicine, Pittsburgh, PA 15213, USA
| | - Yejie Shi
- Center of Cerebrovascular Disease Research, University of Pittsburgh School of Medicine, Pittsburgh, PA 15213, USA
| | - Yanqin Gao
- State Key Laboratory of Medical Neurobiology and Institute of Brain Sciences, Fudan University, Shanghai, China
| | - Ping Zheng
- State Key Laboratory of Medical Neurobiology and Institute of Brain Sciences, Fudan University, Shanghai, China
| | - Jun Chen
- Center of Cerebrovascular Disease Research, University of Pittsburgh School of Medicine, Pittsburgh, PA 15213, USA; State Key Laboratory of Medical Neurobiology and Institute of Brain Sciences, Fudan University, Shanghai, China; Geriatric Research, Educational and Clinical Center, Veterans Affairs Pittsburgh Health Care System, Pittsburgh, PA 15240, USA.
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13
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14
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Bohdanowicz M, Grinstein S. Role of Phospholipids in Endocytosis, Phagocytosis, and Macropinocytosis. Physiol Rev 2013; 93:69-106. [DOI: 10.1152/physrev.00002.2012] [Citation(s) in RCA: 198] [Impact Index Per Article: 18.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023] Open
Abstract
Endocytosis, phagocytosis, and macropinocytosis are fundamental processes that enable cells to sample their environment, eliminate pathogens and apoptotic bodies, and regulate the expression of surface components. While a great deal of effort has been devoted over many years to understanding the proteins involved in these processes, the important contribution of phospholipids has only recently been appreciated. This review is an attempt to collate and analyze the rapidly emerging evidence documenting the role of phospholipids in clathrin-mediated endocytosis, phagocytosis, and macropinocytosis. A primer on phospholipid biosynthesis, catabolism, subcellular distribution, and transport is presented initially, for reference, together with general considerations of the effects of phospholipids on membrane curvature and charge. This is followed by a detailed analysis of the critical functions of phospholipids in the internalization processes and in the maturation of the resulting vesicles and vacuoles as they progress along the endo-lysosomal pathway.
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Affiliation(s)
- Michal Bohdanowicz
- Division of Cell Biology, Hospital for Sick Children, and Institute of Medical Sciences, University of Toronto, Toronto, Canada
| | - Sergio Grinstein
- Division of Cell Biology, Hospital for Sick Children, and Institute of Medical Sciences, University of Toronto, Toronto, Canada
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Flannagan RS, Jaumouillé V, Grinstein S. The Cell Biology of Phagocytosis. ANNUAL REVIEW OF PATHOLOGY-MECHANISMS OF DISEASE 2012; 7:61-98. [PMID: 21910624 DOI: 10.1146/annurev-pathol-011811-132445] [Citation(s) in RCA: 647] [Impact Index Per Article: 53.9] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Affiliation(s)
- Ronald S. Flannagan
- Program in Cell Biology, Hospital for Sick Children, Toronto, Ontario M5G 1X8, Canada;
| | - Valentin Jaumouillé
- Program in Cell Biology, Hospital for Sick Children, Toronto, Ontario M5G 1X8, Canada;
| | - Sergio Grinstein
- Program in Cell Biology, Hospital for Sick Children, Toronto, Ontario M5G 1X8, Canada;
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16
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Park H, Ishihara D, Cox D. Regulation of tyrosine phosphorylation in macrophage phagocytosis and chemotaxis. Arch Biochem Biophys 2011; 510:101-11. [PMID: 21356194 PMCID: PMC3114168 DOI: 10.1016/j.abb.2011.02.019] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2010] [Revised: 02/15/2011] [Accepted: 02/18/2011] [Indexed: 12/22/2022]
Abstract
Macrophages display a large variety of surface receptors that are critical for their normal cellular functions in host defense, including finding sites of infection (chemotaxis) and removing foreign particles (phagocytosis). However, inappropriate regulation of these processes can lead to human diseases. Many of these receptors utilize tyrosine phosphorylation cascades to initiate and terminate signals leading to cell migration and clearance of infection. Actin remodeling dominates these processes and many regulators have been identified. This review focuses on how tyrosine kinases and phosphatases regulate actin dynamics leading to macrophage chemotaxis and phagocytosis.
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Affiliation(s)
- Haein Park
- Department of Anatomy and Structural Biology, Albert Einstein College of Medicine, Bronx, NY, 10461, USA
| | - Dan Ishihara
- Department of Anatomy and Structural Biology, Albert Einstein College of Medicine, Bronx, NY, 10461, USA
| | - Dianne Cox
- Department of Anatomy and Structural Biology, Albert Einstein College of Medicine, Bronx, NY, 10461, USA
- Department of Developmental and Molecular Biology, Albert Einstein College of Medicine, Bronx, NY, 10461, USA
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17
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McMaken S, Exline MC, Mehta P, Piper M, Wang Y, Fischer SN, Newland CA, Schrader CA, Balser SR, Sarkar A, Baran CP, Marsh CB, Cook CH, Phillips GS, Ali NA. Thrombospondin-1 contributes to mortality in murine sepsis through effects on innate immunity. PLoS One 2011; 6:e19654. [PMID: 21573017 PMCID: PMC3090410 DOI: 10.1371/journal.pone.0019654] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2010] [Accepted: 04/13/2011] [Indexed: 01/15/2023] Open
Abstract
Background Thrombospondin-1 (TSP-1) is involved in many biological processes, including immune and tissue injury response, but its role in sepsis is unknown. Cell surface expression of TSP-1 on platelets is increased in sepsis and could activate the anti-inflammatory cytokine transforming growth factor beta (TGFβ1) affecting outcome. Because of these observations we sought to determine the importance of TSP-1 in sepsis. Methodology/Principal Findings We performed studies on TSP-1 null and wild type (WT) C57BL/6J mice to determine the importance of TSP-1 in sepsis. We utilized the cecal ligation puncture (CLP) and intraperitoneal E.coli injection (IP E.coli) models of peritoneal sepsis. Additionally, bone-marrow-derived macrophages (BMMs) were used to determine phagocytic activity. TSP-1−/− animals experienced lower mortality than WT mice after CLP. Tissue and peritoneal lavage TGFβ1 levels were unchanged between animals of each genotype. In addition, there is no difference between the levels of major innate cytokines between the two groups of animals. PLF from WT mice contained a greater bacterial load than TSP-1−/− mice after CLP. The survival advantage for TSP-1−/− animals persisted when IP E.coli injections were performed. TSP-1−/− BMMs had increased phagocytic capacity compared to WT. Conclusions TSP-1 deficiency was protective in two murine models of peritoneal sepsis, independent of TGFβ1 activation. Our studies suggest TSP-1 expression is associated with decreased phagocytosis and possibly bacterial clearance, leading to increased peritoneal inflammation and mortality in WT mice. These data support the contention that TSP-1 should be more fully explored in the human condition.
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Affiliation(s)
- Sara McMaken
- Division of Pulmonary, Allergy, Critical Care, and Sleep Medicine, Department of Internal Medicine, The Dorothy M. Davis Heart and Lung Research Institute, Ohio State University, Columbus, Ohio, United States of America
| | - Matthew C. Exline
- Division of Pulmonary, Allergy, Critical Care, and Sleep Medicine, Department of Internal Medicine, The Dorothy M. Davis Heart and Lung Research Institute, Ohio State University, Columbus, Ohio, United States of America
| | - Payal Mehta
- Division of Pulmonary, Allergy, Critical Care, and Sleep Medicine, Department of Internal Medicine, The Dorothy M. Davis Heart and Lung Research Institute, Ohio State University, Columbus, Ohio, United States of America
| | - Melissa Piper
- Division of Pulmonary, Allergy, Critical Care, and Sleep Medicine, Department of Internal Medicine, The Dorothy M. Davis Heart and Lung Research Institute, Ohio State University, Columbus, Ohio, United States of America
| | - Yijie Wang
- Division of Pulmonary, Allergy, Critical Care, and Sleep Medicine, Department of Internal Medicine, The Dorothy M. Davis Heart and Lung Research Institute, Ohio State University, Columbus, Ohio, United States of America
| | - Sara N. Fischer
- Division of Pulmonary, Allergy, Critical Care, and Sleep Medicine, Department of Internal Medicine, The Dorothy M. Davis Heart and Lung Research Institute, Ohio State University, Columbus, Ohio, United States of America
| | - Christie A. Newland
- Division of Pulmonary, Allergy, Critical Care, and Sleep Medicine, Department of Internal Medicine, The Dorothy M. Davis Heart and Lung Research Institute, Ohio State University, Columbus, Ohio, United States of America
| | - Carrie A. Schrader
- Division of Pulmonary, Allergy, Critical Care, and Sleep Medicine, Department of Internal Medicine, The Dorothy M. Davis Heart and Lung Research Institute, Ohio State University, Columbus, Ohio, United States of America
| | - Shannon R. Balser
- Division of Pulmonary, Allergy, Critical Care, and Sleep Medicine, Department of Internal Medicine, The Dorothy M. Davis Heart and Lung Research Institute, Ohio State University, Columbus, Ohio, United States of America
| | - Anasuya Sarkar
- Division of Pulmonary, Allergy, Critical Care, and Sleep Medicine, Department of Internal Medicine, The Dorothy M. Davis Heart and Lung Research Institute, Ohio State University, Columbus, Ohio, United States of America
| | - Christopher P. Baran
- Division of Pulmonary, Allergy, Critical Care, and Sleep Medicine, Department of Internal Medicine, The Dorothy M. Davis Heart and Lung Research Institute, Ohio State University, Columbus, Ohio, United States of America
| | - Clay B. Marsh
- Division of Pulmonary, Allergy, Critical Care, and Sleep Medicine, Department of Internal Medicine, The Dorothy M. Davis Heart and Lung Research Institute, Ohio State University, Columbus, Ohio, United States of America
| | - Charles H. Cook
- Department of Surgery, Ohio State University, Columbus, Ohio, United States of America
| | - Gary S. Phillips
- The Center for Biostatistics, Ohio State University, Columbus, Ohio, United States of America
| | - Naeem A. Ali
- Division of Pulmonary, Allergy, Critical Care, and Sleep Medicine, Department of Internal Medicine, The Dorothy M. Davis Heart and Lung Research Institute, Ohio State University, Columbus, Ohio, United States of America
- * E-mail:
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18
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van der Poel CE, Spaapen RM, van de Winkel JGJ, Leusen JHW. Functional Characteristics of the High Affinity IgG Receptor, FcγRI. THE JOURNAL OF IMMUNOLOGY 2011; 186:2699-704. [DOI: 10.4049/jimmunol.1003526] [Citation(s) in RCA: 126] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
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19
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Hořejší V, Otáhal P, Brdička T. LAT - an important raft-associated transmembrane adaptor protein. Delivered on 6 July 2009 at the 34th FEBS Congress in Prague, Czech Republic. FEBS J 2010; 277:4383-97. [DOI: 10.1111/j.1742-4658.2010.07831.x] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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20
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Orr SJ, McVicar DW. LAB/NTAL/Lat2: a force to be reckoned with in all leukocytes? J Leukoc Biol 2010; 89:11-9. [PMID: 20643813 DOI: 10.1189/jlb.0410221] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
LAB/NTAL/Lat2 is a transmembrane adaptor protein closely related to LAT. It is expressed in various myeloid and lymphoid cells, many of which also express LAT. Phosphorylation of LAB occurs following engagement of various ITAM- and non-ITAM-linked receptors and can play positive and negative roles following receptor engagement. LAT binds PLCγ directly, resulting in efficient Ca²+ flux and degranulation. However, LAB does not contain a PLCγ-binding motif and only binds PLCγ indirectly, possibly via Grb2, thereby resulting in suboptimal signaling. As LAT can signal more efficiently than LAB, competition between the 2 for space/substrates in the lipid rafts can attenuate signaling. This competition model requires coexpression of LAT; however, LAB is repressive, even in cells lacking substantial LAT expression such as macrophages and mature B cells. The reported interaction between LAB and the ubiquitin E3-ligase c-Cbl suggests 1 possible mechanism for LAT-independent inhibition by LAB, but such a model requires further investigation. Given the wide-reaching expression pattern of LAB, LAB has the ability to modulate signaling in virtually every type of leukocyte. Regardless of its ultimate mode of action, the potent regulatory capability of LAB proves this protein to be a complex adaptor that warrants continued, substantial scrutiny by biochemists and immunologists alike.
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Affiliation(s)
- Selinda J Orr
- Cancer and Inflammation Program, National Cancer Institute-Frederick, Frederick, MD 21702, USA
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21
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Syed SN, Konrad S, Wiege K, Nieswandt B, Nimmerjahn F, Schmidt RE, Gessner JE. Both FcgammaRIV and FcgammaRIII are essential receptors mediating type II and type III autoimmune responses via FcRgamma-LAT-dependent generation of C5a. Eur J Immunol 2010; 39:3343-56. [PMID: 19795417 DOI: 10.1002/eji.200939884] [Citation(s) in RCA: 55] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
FcgammaRIV is a relatively new IgG Fc receptor (FcgammaR) that is reported to contribute to the pathogenesis of autoimmune diseases, although its specific role in relation to FcgammaRIII, complement and IgG2 subclasses remains uncertain. Here we define FcgammaRIV on macrophages as a receptor for soluble IgG2a/b complexes but not for cellular bound IgG2a and show that simultaneous activation of FcgammaRIV and FcgammaRIII is critical to mediate certain type II/III autoimmune responses. FcgammaRIII-deficient mice display compensatory enhanced FcgammaRIV expression, are protected from lung inflammation after deposition of IgG complexes, and show reduced sensitivity to IgG2a/b-mediated hemolytic anemia, indicating that increased FcgammaRIV alone is not sufficient to trigger these diseases in the absence of FcgammaRIII. Importantly, however, blockade of FcgammaRIV is also effective in inhibiting phagocytosis and cytokine production in IgG2b-induced anemia and acute lung injury, processes that display a further dependence on C5a anaphylatoxin receptor. Using gene deletion and functional inhibition studies, we found that FcgammaRIII and FcgammaRIV are each essential to trigger an FcRgamma-linker for activation of T-cell-dependent signal that drives C5a production in the Arthus reaction. Together, the results demonstrate a combined requirement for FcgammaRIII and FcgammaRIV in autoimmune injury, and identify the linker for activation of T cells adaptor as an integral component of linked FcgammaR and C5a anaphylatoxin receptor activation to generate inflammation.
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Affiliation(s)
- Shahzad N Syed
- Laboratory for Molecular Immunology, Clinic for Immunology and Rheumatology, Hannover Medical School, Hannover, Germany
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22
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Whittaker GC, Orr SJ, Quigley L, Hughes L, Francischetti IMB, Zhang W, McVicar DW. The linker for activation of B cells (LAB)/non-T cell activation linker (NTAL) regulates triggering receptor expressed on myeloid cells (TREM)-2 signaling and macrophage inflammatory responses independently of the linker for activation of T cells. J Biol Chem 2009; 285:2976-85. [PMID: 19948717 DOI: 10.1074/jbc.m109.038398] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
Abstract
Triggering receptor expressed on myeloid cells-2 (TREM-2) is rapidly emerging as a key regulator of the innate immune response via its regulation of macrophage inflammatory responses. Here we demonstrate that proximal TREM-2 signaling parallels other DAP12-based receptor systems in its use of Syk and Src-family kinases. However, we find that the linker for activation of T cells (LAT) is severely reduced as monocytes differentiate into macrophages and that TREM-2 exclusively uses the linker for activation of B cells (LAB encoded by the gene Lat2(-/-)) to mediate downstream signaling. LAB is required for TREM-2-mediated activation of Erk1/2 and dampens proximal TREM-2 signals through a novel LAT-independent mechanism resulting in macrophages with proinflammatory properties. Thus, Lat2(-/-) macrophages have increased TREM-2-induced proximal phosphorylation, and lipopolysaccharide stimulation of these cells leads to increased interleukin-10 (IL-10) and decreased IL-12p40 production relative to wild type cells. Together these data identify LAB as a critical, LAT-independent regulator of TREM-2 signaling and macrophage development capable of controlling subsequent inflammatory responses.
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Affiliation(s)
- Gillian C Whittaker
- Cancer and Inflammation Program, Center for Cancer Research, NCI-Frederick, National Institutes of Health, Frederick, Maryland 21702, USA
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Lu HK, Rentero C, Raftery MJ, Borges L, Bryant K, Tedla N. Leukocyte Ig-like receptor B4 (LILRB4) is a potent inhibitor of FcgammaRI-mediated monocyte activation via dephosphorylation of multiple kinases. J Biol Chem 2009; 284:34839-48. [PMID: 19833736 DOI: 10.1074/jbc.m109.035683] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The leukocyte immunoglobulin-like receptor (LILR) B4 belongs to a family of cell surface receptors that possesses cytoplasmic immunoreceptor tyrosine-based inhibitory motifs (ITIMs). LILRB4 is believed to down-regulate activation signals mediated by non-receptor tyrosine kinase cascades through the recruitment of SHP-1. However, the exact mechanisms of LILRB4-mediated inhibition are not fully elucidated. In this study, we demonstrate high level surface expression of LILRB4 on THP-1 cells and primary peripheral blood monocytes, which profoundly inhibited production of a key pro-inflammatory cytokine (TNFalpha) induced by FcgammaRI (CD64). We also report that LILRB4 aggregated to sites of activation upon co-ligation with CD64 and that this may enhance its inhibitory effects. Cross-linking of CD64 on THP-1 cells markedly increased phosphorylation of multiple proteins including tyrosine kinases and signaling molecules (Lck, Syk, LAT, and Erk), an adaptor protein that targets protein-tyrosine kinases for degradation (c-Cbl) and a protein involved in the formation of actin cytoskeletal rearrangement (alpha-actinin-4). Co-ligation of LILRB4 considerably reduced CD64-mediated phosphorylation of Lck, Syk, LAT, Erk, and c-Cbl but not alpha-actinin-4, suggesting selective inhibition of signaling molecules. Treatment of cells with a broad-spectrum phosphatase inhibitor, sodium pervanadate (SP), significantly reversed LILRB4-mediated inhibition of TNFalpha production and protein tyrosine phosphorylation. In comparison, treatment with an SHP-1 specific inhibitor, sodium stibogluconate (SS) has no effects indicating involvement of phosphatase(s) other than SHP-1 in LILRB4 signaling. Collectively, our data show LILRB4 is a potent inhibitor of monocytes activation. This may provide a new potential therapeutic strategy for inflammatory conditions characterized by excessive TNFalpha production.
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Affiliation(s)
- Hao Kim Lu
- Centre for Infection and Inflammation Research, University of New South Wales, Sydney, New South Wales 2052, Australia
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Mehta H, Glogauer M, Bécart S, Altman A, Coggeshall KM. Adaptor protein SLAT modulates Fcgamma receptor-mediated phagocytosis in murine macrophages. J Biol Chem 2009; 284:11882-91. [PMID: 19251698 PMCID: PMC2673257 DOI: 10.1074/jbc.m809712200] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/26/2008] [Revised: 02/18/2009] [Indexed: 12/19/2022] Open
Abstract
SLAT (SWAP-70-like adaptor protein of T cells) is an adaptor protein expressed in cells of the hematopoietic system. SLAT interacts with and alters the function of small GTPase Rac1 in fibroblasts. In these nonhematopoietic models, the SLAT-Rac interaction leads to changes in F-actin and causes cytoskeletal reorganization. In T cells, SLAT expression regulates the development of T helper cells through Cdc42- and Rac1-mediated activation of the NF-AT transcription factor. Here we show that SLAT is expressed in macrophages. Overexpression of SLAT in a macrophage cell line inhibits the IgG Fcgamma receptor-mediated phagocytic ability of THP1 cells. In bone marrow-derived macrophages, SLAT protein is recruited to the early phagosomes formed via Fcgamma receptor engagement. SLAT recruitment to the phagosome was most efficient when the macrophages express at least one isoform of Rac (Rac1 or Rac2), because SLAT recruitment was reduced in macrophages of Rac-deficient mice. Macrophages derived from animals lacking SLAT show an elevation in the rate of Fcgamma receptor-mediated phagocytosis. The absence of SLAT is associated with an increase in the amount of F-actin formed around these phagosomes as well as an increase in the amount of Rac1 protein recruited to the phagosome. Our results suggest that SLAT acts as a gatekeeper for the amount of Rac recruited to the phagosomes formed by Fcgamma receptor engagement and thus is able to regulate F-actin re-organization and consequently phagocytosis.
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Affiliation(s)
- Harshini Mehta
- Program in Immunobiology and Cancer, Oklahoma Medical Research Foundation, and Department of Cell Biology, University of Oklahoma, Oklahoma City, Oklahoma 73104, USA
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25
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Gibbings D, Befus AD. CD4 and CD8: an inside-out coreceptor model for innate immune cells. J Leukoc Biol 2009; 86:251-9. [PMID: 19401396 DOI: 10.1189/jlb.0109040] [Citation(s) in RCA: 55] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
CD8 and CD4 are expressed by several cell types that do not express TCR. These include DCs, macrophages, monocytes, and NK cells. CD8(+) monocytes and macrophages are abundant at the site of pathology in many rat disease models, particularly those involving immune complex-mediated pathology. Indeed, in some disease models, CD8(+) macrophages correlate with severity of pathology or directly cause pathology or tumor cell killing. Evidence suggests CD8 or CD4 can enhance FcgammaR-dependent responses of human monocytes. Building on data that key components of TCR and FcgammaR signaling can substitute one another efficiently, we postulate that CD4 and CD8 operate with FcgammaR and potentially other receptors to enhance responses of T cells and various innate immune cells. Our model suggests CD8 on myeloid cells may contribute directly to tumor killing and tissue pathology by enhancing FcgammaR responses. Moreover, the model suggests a role for CD8 in cross-presentation of antibody-associated antigen by DCs and a new mechanism to regulate TCR sensitivity.
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Affiliation(s)
- Derrick Gibbings
- Department of Medicine, University of Alberta, Edmonton, Alberta, Canada.
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Bryant PA, Smyth GK, Robins-Browne R, Curtis N. Detection of gene expression in an individual cell type within a cell mixture using microarray analysis. PLoS One 2009; 4:e4427. [PMID: 19212463 PMCID: PMC2639697 DOI: 10.1371/journal.pone.0004427] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2008] [Accepted: 12/12/2008] [Indexed: 12/14/2022] Open
Abstract
BACKGROUND A central issue in the design of microarray-based analysis of global gene expression is the choice between using cells of single type and a mixture of cells. This study quantified the proportion of lipopolysaccharide (LPS) induced differentially expressed monocyte genes that could be measured in peripheral blood mononuclear cells (PBMC), and determined the extent to which gene expression in the non-monocyte cell fraction diluted or obscured fold changes that could be detected in the cell mixture. METHODOLOGY/PRINCIPAL FINDINGS Human PBMC were stimulated with LPS, and monocytes were then isolated by positive (Mono+) or negative (Mono-) selection. The non-monocyte cell fraction (MonoD) remaining after positive selection of monocytes was used to determine the effect of non-monocyte cells on overall expression. RNA from LPS-stimulated PBMC, Mono+, Mono- and MonoD samples was co-hybridised with unstimulated RNA for each cell type on oligonucleotide microarrays. There was a positive correlation in gene expression between PBMC and both Mono+ (0.77) and Mono- (0.61-0.67) samples. Analysis of individual genes that were differentially expressed in Mono+ and Mono- samples showed that the ability to detect expression of some genes was similar when analysing PBMC, but for others, differential expression was either not detected or changed in the opposite direction. As a result of the dilutional or obscuring effect of gene expression in non-monocyte cells, overall about half of the statistically significant LPS-induced changes in gene expression in monocytes were not detected in PBMC. However, 97% of genes with a four fold or greater change in expression in monocytes after LPS stimulation, and almost all (96-100%) of the top 100 most differentially expressed monocyte genes were detected in PBMC. CONCLUSIONS/SIGNIFICANCE The effect of non-responding cells in a mixture dilutes or obscures the detection of subtle changes in gene expression in an individual cell type. However, for studies in which only the most highly differentially expressed genes are of interest, separating and analysing individual cell types may be unnecessary.
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Affiliation(s)
- Penelope A. Bryant
- Department of Paediatrics, The University of Melbourne, Royal Children's Hospital Melbourne, Parkville, Victoria, Australia
- Microbiology & Infectious Diseases Research Group, Murdoch Children's Research Institute, Royal Children's Hospital Melbourne, Parkville, Victoria, Australia
- Infectious Diseases Unit, Department of General Medicine, Royal Children's Hospital Melbourne, Parkville, Victoria, Australia
| | - Gordon K. Smyth
- Bioinformatics Division, Walter and Eliza Hall Institute of Medical Research, Parkville, Victoria, Australia
| | - Roy Robins-Browne
- Microbiology & Infectious Diseases Research Group, Murdoch Children's Research Institute, Royal Children's Hospital Melbourne, Parkville, Victoria, Australia
- Department of Microbiology & Immunology, University of Melbourne, Parkville, Victoria, Australia
| | - Nigel Curtis
- Department of Paediatrics, The University of Melbourne, Royal Children's Hospital Melbourne, Parkville, Victoria, Australia
- Microbiology & Infectious Diseases Research Group, Murdoch Children's Research Institute, Royal Children's Hospital Melbourne, Parkville, Victoria, Australia
- Infectious Diseases Unit, Department of General Medicine, Royal Children's Hospital Melbourne, Parkville, Victoria, Australia
- * E-mail:
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Zhu JW, Brdicka T, Katsumoto TR, Lin J, Weiss A. Structurally distinct phosphatases CD45 and CD148 both regulate B cell and macrophage immunoreceptor signaling. Immunity 2008; 28:183-96. [PMID: 18249142 DOI: 10.1016/j.immuni.2007.11.024] [Citation(s) in RCA: 119] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2007] [Revised: 10/25/2007] [Accepted: 11/15/2007] [Indexed: 12/22/2022]
Abstract
The receptor-type protein tyrosine phosphatase (RPTP) CD148 is thought to have an inhibitory function in signaling and proliferation in nonhematopoietic cells. However, its role in the immune system has not been thoroughly studied. Our analysis of CD148 loss-of-function mice showed that CD148 has a positive regulatory function in B cells and macrophages, similar to the role of CD45 as a positive regulator of Src family kinases (SFKs). Analysis of CD148 and CD45 doubly deficient B cells and macrophages revealed hyperphosphorylation of the C-terminal inhibitory tyrosine of SFKs accompanied by substantial alterations in B and myeloid lineage development and defective immunoreceptor signaling. Because these findings suggest the C-terminal tyrosine of SFKs is a common substrate for both CD148 and CD45 phosphatases and imply a level of redundancy not previously appreciated, a reassessment of the function of CD45 in the B and myeloid lineages based on prior data from the CD45-deficient mouse is warranted.
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MESH Headings
- Animals
- B-Lymphocytes/immunology
- B-Lymphocytes/metabolism
- Crosses, Genetic
- Cytokines/metabolism
- Leukocyte Common Antigens/deficiency
- Leukocyte Common Antigens/genetics
- Leukocyte Common Antigens/immunology
- Leukocyte Common Antigens/metabolism
- Macrophages/immunology
- Macrophages/metabolism
- Mice
- Mice, Inbred C57BL
- Mice, Mutant Strains
- Phagocytosis
- Receptor-Like Protein Tyrosine Phosphatases, Class 3/deficiency
- Receptor-Like Protein Tyrosine Phosphatases, Class 3/genetics
- Receptor-Like Protein Tyrosine Phosphatases, Class 3/immunology
- Receptor-Like Protein Tyrosine Phosphatases, Class 3/metabolism
- Receptors, Antigen, B-Cell/immunology
- Receptors, Antigen, B-Cell/metabolism
- Signal Transduction
- src-Family Kinases/metabolism
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Affiliation(s)
- Jing W Zhu
- Departments of Medicine and of Microbiology and Immunology, Howard Hughes Medical Institute, Rosalind Russell Medical Research Center for Arthritis, University of California-San Francisco, San Francisco, CA 94143, USA
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Abstract
Adapters are multidomain molecules that recruit effector proteins during signal transduction by immunoreceptors and integrins. The absence of these scaffolding molecules profoundly affects development and function of various hematopoietic lineages, underscoring their importance as regulators of signaling cascades. An emerging aspect of the mechanism by which engaged immunoreceptors and integrins transmit signals within the cell is by differential usage of various adapters that function to nucleate formation of distinct signaling complexes in a specific location within the cell. In this review, we discuss the mechanisms by which adapter proteins coordinate signal transduction with an emphasis on the role of subcellular compartmentalization in adapter function.
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Affiliation(s)
- Natalie Bezman
- Abramson Family Cancer Research Institute, University of Pennsylvania, Philadelphia, PA 19104, USA
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30
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Gibbings DJ, Marcet-Palacios M, Sekar Y, Ng MCY, Befus AD. CD8 alpha is expressed by human monocytes and enhances Fc gamma R-dependent responses. BMC Immunol 2007; 8:12. [PMID: 17678538 PMCID: PMC2000912 DOI: 10.1186/1471-2172-8-12] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2007] [Accepted: 08/01/2007] [Indexed: 01/06/2023] Open
Abstract
Background CD8α enhances the responses of antigen-specific CTL activated through TCR through binding MHC class I, favoring lipid raft partitioning of TCR, and inducing intracellular signaling. CD8α is also found on dendritic cells and rat macrophages, but whether CD8α enhances responses of a partner receptor, like TCR, to activate these cells is not known. TCR and FcR, use analogous or occasionally interchangeable signaling mechanisms suggesting the possibility that CD8α co-activates FcR responses. Interestingly, CD8α+ monocytes are often associated with rat models of disease involving immune-complex deposition and FcR-mediated pathology, such as arthritis, glomerulonephritis, ischaemia, and tumors. While rat macrophages have been shown to express CD8α evidence for CD8α expression by mouse or human monocytes or macrophages was incomplete. Results We detected CD8α, but not CD8β on human monocytes and the monocytic cell line THP-1 by flow cytometry. Reactivity of anti-CD8α mAb with monocytes is at least partly independent of FcR as anti-CD8α mAb detect CD8α by western blot and inhibit binding of MHC class I tetramers. CD8α mRNA is also found in monocytes and THP-1 suggesting CD8α is synthesized by monocytes and not acquired from other CD8α+ cell types. Interestingly, CD8α from monocytes and blood T cells presented distinguishable patterns by 2-D electrophoresis. Anti-CD8α mAb alone did not activate monocyte TNF release. In comparison, TNF release by human monocytes stimulated in a FcR-dependent manner with immune-complexes was enhanced by inclusion of anti-CD8α mAb in immune-complexes. Conclusion Human monocytes express CD8α. Co-engagement of CD8α and FcR enhances monocyte TNF release, suggesting FcR may be a novel partner receptor for CD8α on innate immune cells.
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Affiliation(s)
- Derrick J Gibbings
- Pulmonary Research Group, Division of Pulmonary Medicine, Department of Medicine, University of Alberta, Canada
| | - Marcelo Marcet-Palacios
- Pulmonary Research Group, Division of Pulmonary Medicine, Department of Medicine, University of Alberta, Canada
| | - Yokananth Sekar
- Pulmonary Research Group, Division of Pulmonary Medicine, Department of Medicine, University of Alberta, Canada
| | - Marcus CY Ng
- Pulmonary Research Group, Division of Pulmonary Medicine, Department of Medicine, University of Alberta, Canada
| | - A Dean Befus
- Pulmonary Research Group, Division of Pulmonary Medicine, Department of Medicine, University of Alberta, Canada
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31
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Nie Z, Bren GD, Vlahakis SR, Schimnich AA, Brenchley JM, Trushin SA, Warren S, Schnepple DJ, Kovacs CM, Loutfy MR, Douek DC, Badley AD. Human immunodeficiency virus type 1 protease cleaves procaspase 8 in vivo. J Virol 2007; 81:6947-56. [PMID: 17442709 PMCID: PMC1933285 DOI: 10.1128/jvi.02798-06] [Citation(s) in RCA: 57] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
Human immunodeficiency virus type 1 (HIV-1) infection causes apoptosis of infected CD4 T cells as well as uninfected (bystander) CD4 and CD8 T cells. It remains unknown what signals cause infected cells to die. We demonstrate that HIV-1 protease specifically cleaves procaspase 8 to create a novel fragment termed casp8p41, which independently induces apoptosis. casp8p41 is specific to HIV-1 protease-induced death but not other caspase 8-dependent death stimuli. In HIV-1-infected patients, casp8p41 is detected only in CD4(+) T cells, predominantly in the CD27(+) memory subset, its presence increases with increasing viral load, and it colocalizes with both infected and apoptotic cells. These data indicate that casp8p41 independently induces apoptosis and is a specific product of HIV-1 protease which may contribute to death of HIV-1-infected cells.
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Affiliation(s)
- Zilin Nie
- Division of Infectious Diseases, Mayo Clinic College of Medicine, 200 First Street SW, Rochester, MN 55905, USA
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32
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Tessarz AS, Weiler S, Zanzinger K, Angelisová P, Horejsí V, Cerwenka A. Non-T Cell Activation Linker (NTAL) Negatively Regulates TREM-1/DAP12-Induced Inflammatory Cytokine Production in Myeloid Cells. THE JOURNAL OF IMMUNOLOGY 2007; 178:1991-9. [PMID: 17277102 DOI: 10.4049/jimmunol.178.4.1991] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
The engagement of triggering receptor expressed on myeloid cells 1 (TREM-1) on macrophages and neutrophils leads to TNF-alpha and IL-8 production and enhances inflammatory responses to microbial products. For signal transduction, TREM-1 couples to the ITAM-containing adapter DNAX activation protein of 12 kDa (DAP12). In general, ITAM-mediated signals lead to cell activation, although DAP12 was recently implicated in inhibitory signaling in mouse macrophages and dendritic cells. To date, signals downstream of the TREM-1 and DAP12 complex in myeloid cells are poorly defined. By analyzing receptor-induced tyrosine phosphorylation patterns, we discovered that the ligation of TREM-1 leads to tyrosine phosphorylation of the non-T cell activation linker (NTAL; also called linker of activation in B cells or LAB) in a myelomonocytic cell line and primary human granulocytes. Using RNA interference to decrease the expression levels of NTAL, we demonstrate that in NTAL knockdown cell lines the phosphorylation of ERK1/2 is enhanced. In addition, low levels of NTAL are correlated with decreased and delayed mobilization of Ca(2+) after TREM-1 triggering. Most importantly, we demonstrate that NTAL acts as a negative regulator of TNF-alpha and IL-8 production after stimulation via TREM-1. Our results show that activation signals delivered via DAP12 can be counterbalanced by the adaptor NTAL, identifying NTAL as gatekeeper of TREM-1/DAP12-induced signaling in myeloid cells.
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Affiliation(s)
- Anja S Tessarz
- German Cancer Research Center (DKFZ), Division of Innate Immunity, Heidelberg, Germany, Europe
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33
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Joshi T, Butchar JP, Tridandapani S. Fcgamma receptor signaling in phagocytes. Int J Hematol 2006; 84:210-216. [PMID: 17050193 DOI: 10.1532/ijh97.06140] [Citation(s) in RCA: 46] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2006] [Accepted: 07/05/2006] [Indexed: 01/16/2023]
Abstract
Fcgamma receptors are among the best-studied phagocytic receptors. The key features of Fcgamma receptor-mediated phagocytosis include phagocytic cup formation by extensive actin cytoskeletal rearrangements, particle engulfment, and the release of proinflammatory mediators such as cytokines and reactive oxygen species. These events are elegantly regulated by the simultaneous engagement of activating and inhibitory Fcgamma receptors and by intracellular signaling molecules. Extensive studies in the past several years have defined the molecular mechanisms of the phagocytic process. The purpose of this review is to revisit some of the well-established signaling pathways as well as to summarize the new findings in this field.
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Affiliation(s)
- Trupti Joshi
- Department of Internal Medicine, Dorothy M. Davis Heart and Lung Research Institute and Comprehensive Cancer Center, The Ohio State University, Columbus, Ohio, USA
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34
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Yeung T, Ozdamar B, Paroutis P, Grinstein S. Lipid metabolism and dynamics during phagocytosis. Curr Opin Cell Biol 2006; 18:429-37. [PMID: 16781133 DOI: 10.1016/j.ceb.2006.06.006] [Citation(s) in RCA: 86] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2006] [Accepted: 06/06/2006] [Indexed: 12/24/2022]
Abstract
Phagocytosis, the engulfment of particles, mediates the elimination of invading pathogens as well as the clearance of apoptotic cells. Ingested particles reside within a vacuole or phagosome, where they are eventually destroyed and digested. The phagosomal lumen acquires microbicidal and digestive properties through interaction with various components of the endocytic pathway, a process known as maturation. Lipids are known to have numerous roles in phagosome formation and maturation; recent developments in the design of lipid-specific probes and in high-resolution imaging have revealed that lipids, notably phosphoinositides, are involved in signaling, actin assembly and the recruitment of molecular motors to sites of ingestion. In addition, phosphoinositides and other lipids also regulate multiple membrane budding, fission and fusion events required for maturation.
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Affiliation(s)
- Tony Yeung
- Division of Cell Biology, The Hospital for Sick Children, Institute of Medical Sciences, University of Toronto, Toronto, M5S 1A8, Canada
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35
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Chen CN, Chang SF, Lee PL, Chang K, Chen LJ, Usami S, Chien S, Chiu JJ. Neutrophils, lymphocytes, and monocytes exhibit diverse behaviors in transendothelial and subendothelial migrations under coculture with smooth muscle cells in disturbed flow. Blood 2005; 107:1933-42. [PMID: 16293605 PMCID: PMC1895706 DOI: 10.1182/blood-2005-08-3137] [Citation(s) in RCA: 56] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Atherosclerosis develops at regions of the arterial tree exposed to disturbed flow. The early stage of atherogenesis involves the adhesion of leukocytes (white blood cells [WBCs]) to and their transmigration across endothelial cells (ECs), which are located in close proximity to smooth muscle cells (SMCs). We investigated the effects of EC/SMC coculture and disturbed flow on the adhesion and transmigration of 3 types of WBCs (neutrophils, peripheral blood lymphocytes [PBLs], and monocytes) using our vertical-step flow (VSF) chamber, in which ECs were cocultured with SMCs in collagen gels. Such coculture significantly increased the adhesion and transmigration of neutrophils, PBLs, and monocytes under VSF, particularly in the reattachment area, where the rolling velocity of WBCs and their transmigration time were decreased, as compared with the other areas. Neutrophils, PBLs, and monocytes showed different subendothelial migration patterns under VSF. Their movements were more random and shorter in distance in the reattachment area. Coculture of ECs and SMCs induced their expressions of adhesion molecules and chemokines, which contributed to the increased WBC adhesion and transmigration. Our findings provide insights into the mechanisms of WBC interaction with the vessel wall (composed of ECs and SMCs) under the complex flow environments found in regions of prevalence for atherogenesis.
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Affiliation(s)
- Cheng-Nan Chen
- Institute of Life Sciences, National Defense Medical Center, National Health Research Institutes, Taiwan, Republic of China
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36
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Abstract
Cells of the immune system carry out diverse functions that are controlled by surface receptors for antigen, costimulatory molecules, cytokines, chemokines, and other ligands. A shared feature of signal transduction downstream of most receptors on immune cells, as in nonhematopoietic cell types, is the activation of phosphoinositide 3-kinase (PI3K). The mechanism by which this common signaling event is elicited by distinct receptors and contributes to unique functional outcomes is an intriguing puzzle. Understanding how specificity is achieved in PI3K signaling is of particular significance because altered regulation of this pathway is observed in many disease states, including leukemia and lymphoma. Here we review recent advances in the understanding of PI3K signaling mechanisms in different immune cells and receptor systems. We emphasize the concept that PI3K and its products are components of complex networks of interacting proteins and second messengers, rather than simple links in linear signaling cascades.
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Affiliation(s)
- Jonathan A Deane
- Department of Molecular Biology and Biochemistry, University of California, Irvine, 92697, USA.
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37
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Cao X, Wei G, Fang H, Guo J, Weinstein M, Marsh CB, Ostrowski MC, Tridandapani S. The inositol 3-phosphatase PTEN negatively regulates Fc gamma receptor signaling, but supports Toll-like receptor 4 signaling in murine peritoneal macrophages. THE JOURNAL OF IMMUNOLOGY 2004; 172:4851-7. [PMID: 15067063 DOI: 10.4049/jimmunol.172.8.4851] [Citation(s) in RCA: 76] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
Fc gamma R clustering in macrophages activates signaling events that result in phagocytosis. Phagocytosis is accompanied by the generation harmful byproducts such as reactive oxygen radicals and production of inflammatory cytokines, which mandate that the phagocytic process be subject to a tight regulation. The molecular mechanisms involved in this regulation are not fully understood. In this study, we have examined the role of the inositol 3-phosphatase and tensin homologue deleted on chromosome 10 (PTEN) in Fc gamma R-induced macrophage function. We demonstrate that in ex vivo murine peritoneal macrophages that are deficient in PTEN expression, Fc gamma R-induced Akt and extracellular signal-regulated kinase phosphorylation are enhanced. Notably, PTEN(-/-) macrophages showed constitutively high phosphorylation of Akt. However, PTEN did not seem to influence tyrosine phosphorylation events induced by Fc gamma R clustering. Furthermore, PTEN(-/-) macrophages displayed enhanced phagocytic ability. Likewise, Fc gamma R-induced production of TNF-alpha, IL-6, and IL-10 was significantly elevated in PTEN(-/-) macrophages. Surprisingly, LPS-induced TNF-alpha production was down-regulated in PTEN(-/-) macrophages. Analyzing the molecular events leading to PTEN influence on LPS/Toll-like receptor 4 (TLR4) signaling, we found that LPS-induced activation of mitogen-activated protein kinases is suppressed in PTEN(-/-) cells. Previous reports indicated that LPS-induced mitogen-activated protein kinase activation is down-regulated by phosphatidylinositol 3-kinase through the activation of Akt. Our observation that Akt activation is basally enhanced in PTEN(-/-) cells suggests that PTEN supports TLR4-induced inflammatory responses by suppressing the activation of Akt. Thus, we conclude that PTEN is a negative regulator of Fc gamma R signaling, but a positive regulator of TLR4 signaling. These findings are the first to demonstrate a role for PTEN in Fc gamma R- and TLR4-mediated macrophage inflammatory response.
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Affiliation(s)
- Xianhua Cao
- Biophysics Program, Ohio State University, Columbus, OH 43210, USA
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38
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Nichols KE, Haines K, Myung PS, Newbrough S, Myers E, Jumaa H, Shedlock DJ, Shen H, Koretzky GA. Macrophage activation and Fcγ receptor-mediated signaling do not require expression of the SLP-76 and SLP-65 adaptors. J Leukoc Biol 2003; 75:541-52. [PMID: 14694181 DOI: 10.1189/jlb.0703312] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
The Src-homology 2 domain-containing, leukocyte-specific phosphoprotein of 76 kDa (SLP-76) is a hematopoietic adaptor that plays a central role during immunoreceptor-mediated activation of T lymphocytes and mast cells and collagen receptor-induced activation of platelets. Despite similar levels of expression in macrophages, SLP-76 is not required for Fc receptor for immunoglobulin G (IgG; FcgammaR)-mediated activation. We hypothesized that the related adaptor SLP-65, which is also expressed in macrophages, may compensate for the loss of SLP-76 during FcgammaR-mediated signaling and functional events. To address this hypothesis, we examined bone marrow-derived macrophages (BMM) from wild-type (WT) mice or mice lacking both of these adaptors. Contrary to our expectations, SLP-76(-/-) SLP-65(-/-) BMM demonstrated normal FcgammaR-mediated activation, including internalization of Ig-coated sheep red blood cells and production of reactive oxygen intermediates. FcgammaR-induced biochemical events were normal in SLP-76(-/-) SLP-65(-/-) BMM, including phosphorylation of phospholipase C and the extracellular signaling-regulated kinases 1 and 2. To determine whether macrophages functioned normally in vivo, we infected WT and SLP-76(-/-) SLP-65(-/-) mice with sublethal doses of Listeria monocytogenes (LM), a bacterium against which the initial host defense is provided by activated macrophages. WT and SLP-76(-/-) SLP-65(-/-) mice survived acute, low-dose infection and showed no difference in the number of liver or spleen LM colony-forming units, a measure of the total body burden of this organism. Taken together, these data suggest that neither SLP-76 nor SLP-65 is required during FcgammaR-dependent signaling and functional events in macrophages.
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Affiliation(s)
- Kim E Nichols
- Pediatric Oncology, Children's Hospital of Philadelphia, PA 19104, USA.
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39
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Ganesan LP, Fang H, Marsh CB, Tridandapani S. The protein-tyrosine phosphatase SHP-1 associates with the phosphorylated immunoreceptor tyrosine-based activation motif of Fc gamma RIIa to modulate signaling events in myeloid cells. J Biol Chem 2003; 278:35710-7. [PMID: 12832410 DOI: 10.1074/jbc.m305078200] [Citation(s) in RCA: 45] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Fc gamma RIIa is a low affinity IgG receptor uniquely expressed in human cells that promotes phagocytosis of immune complexes and induces inflammatory cytokine gene transcription. Recent studies have revealed that phagocytosis initiated by Fc gamma RIIa is tightly controlled by the inositol phosphatase SHIP-1, and the protein-tyrosine phosphatase SHP-1. Whereas the molecular nature of SHIP-1 involvement with Fc gamma RIIa has been well studied, it is not clear how SHP-1 is activated by Fc gamma RIIa to mediate its regulatory effect. Here we report that Fc gamma RIIa clustering induces SHP-1 phosphatase activity in THP-1 cells. Using synthetic phosphopeptides, and stable transfectants expressing immunoreceptor tyrosine-based activation motif (ITAM) tyrosine mutants of Fc gamma RIIa, we demonstrate that SHP-1 associates with the phosphorylated amino-terminal ITAM tyrosine of Fc gamma RIIa, whereas the tyrosine kinase Syk associates with the carboxyl-terminal ITAM tyrosine. Association of SHP-1 with Fc gamma RIIa ITAM appears to suppress total cellular tyrosine phosphorylation. Furthermore, Fc gamma RIIa clustering results in the association of SHP-1 with key signaling molecules such as Syk, p85 subunit of PtdIns 3-kinase, and p62dok, suggesting that these molecules may be substrates of SHP-1 in this system. Finally, overexpression of wild-type SHP-1 but not catalytically deficient SHP-1 led to a down-regulation of NF kappa B-dependent gene transcription in THP-1 cells activated by clustering Fc gamma RIIa.
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MESH Headings
- Antigens, CD/chemistry
- Antigens, CD/genetics
- Antigens, CD/isolation & purification
- Antigens, CD/physiology
- Cell Line
- Humans
- Intracellular Signaling Peptides and Proteins
- Kinetics
- Mutagenesis, Site-Directed
- Phosphorylation
- Protein Tyrosine Phosphatase, Non-Receptor Type 6
- Protein Tyrosine Phosphatases/chemistry
- Protein Tyrosine Phosphatases/genetics
- Protein Tyrosine Phosphatases/metabolism
- Receptors, IgG/chemistry
- Receptors, IgG/genetics
- Receptors, IgG/isolation & purification
- Receptors, IgG/physiology
- Recombinant Proteins/chemistry
- Recombinant Proteins/metabolism
- Signal Transduction/physiology
- Transfection
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Affiliation(s)
- Latha P Ganesan
- Department of Internal Medicine, Division of Pulmonary and Critical Care Medicine, The Dorothy M. Davis Heart and Lung Institute, and Comprehensive Cancer Center, The Ohio State University, Columbus, Ohio 43210, USA
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40
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Pengal RA, Ganesan LP, Fang H, Marsh CB, Anderson CL, Tridandapani S. SHIP-2 inositol phosphatase is inducibly expressed in human monocytes and serves to regulate Fcgamma receptor-mediated signaling. J Biol Chem 2003; 278:22657-63. [PMID: 12690104 DOI: 10.1074/jbc.m302907200] [Citation(s) in RCA: 38] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
SHIP-2, a recently identified inositol 5'-phosphatase, shares high level homology with SHIP-1. Although the role of SHIP-1 has been extensively studied, the role of SHIP-2 in myeloid cell functions is not known. Here, we have analyzed the expression patterns, molecular mechanism of activation, and function of SHIP-2 in human myeloid cell Fcgamma receptor (FcgammaR) signaling. We report that SHIP-2 is expressed in transformed myeloid cells and in primary macrophages, but not in peripheral blood monocytes. Treatment of peripheral blood monocytes with bacterial lipopolysaccharide induced expression of SHIP-2 in a dose-dependent manner. FcgammaRIIa clustering in THP-1 cells induced SHIP-2 tyrosine phosphorylation, suggesting a role for SHIP-2 in modulating FcgammaR-mediated function. Consistent with this notion, overexpression of wild-type SHIP-2 (but not catalytically deficient SHIP-2) in THP-1 cells almost completely abrogated NFkappaB-mediated gene transcription in response to FcgammaRIIa clustering. Furthermore, FcgammaRIIa-induced Akt activation was blocked by wild-type SHIP-2, but not by a catalytically deficient mutant of SHIP-2. Additional experiments analyzing the molecular mechanism of SHIP-2 induction by FcgammaRIIa revealed that SHIP-2 associated with the phosphorylated FcgammaRIIa immunoreceptor tyrosine-based activation motif via the SHIP-2 SH2 domain. Thus, an SH2 domain mutant of SHIP-2 failed to associate with FcgammaRIIa or to become tyrosine-phosphorylated upon FcgammaRIIa clustering. Finally, we also demonstrate that SHIP-2 phosphorylation was induced by FcgammaRI clustering in THP-1 cells. These findings unravel a novel level of regulation of FcgammaR-mediated activation of human myeloid cells by the expression and function of the inositol phosphatase SHIP-2.
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Affiliation(s)
- Ruma A Pengal
- Molecular, Cellular, and Developmental Biology Program, Dorothy M. Davis Heart and Lung Institute, James Cancer Hospital, Ohio State University, Columbus 43210, USA
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41
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Tridandapani S, Wardrop R, Baran CP, Wang Y, Opalek JM, Caligiuri MA, Marsh CB. TGF-beta 1 suppresses [correction of supresses] myeloid Fc gamma receptor function by regulating the expression and function of the common gamma-subunit. JOURNAL OF IMMUNOLOGY (BALTIMORE, MD. : 1950) 2003; 170:4572-7. [PMID: 12707335 DOI: 10.4049/jimmunol.170.9.4572] [Citation(s) in RCA: 68] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
We have previously reported that FcgammaR-mediated function in myeloid cells is a tightly regulated event that is influenced by the cytokines present in the milieu. TGF-beta1 is an immunosuppressive cytokine with pleiotropic effects on immune responses; however, the molecular mechanism by which TGF-beta suppresses immune responses is poorly understood. In this study, we have analyzed the effect of TGF-beta on FcgammaR-mediated activation of myeloid cells. We report that TGF-beta1-treated THP-1 human myeloid cells displayed reduced ability to phagocytose IgG-coated particles. Because FcgammaR expression is modulated by cytokines, we analyzed expression levels of FcgammaRI, FcgammaRIIa, FcgammaRIIb, and FcgammaRIIIa in cells cultured with or without TGF-beta1 and found while total protein levels of the FcgammaR were not reduced, surface expression of FcgammaRI and FcgammaRIII was lower in cells cultured with TGF-beta1. Concomitantly, there was a dose-dependent reduction in the expression of the FcgammaR-associated gamma-subunit. This suppressive effect of TGF-beta was likewise observed in bone marrow-derived murine myeloid cells and human monocytes. Importantly, TGF-beta1 also significantly reduced the production of monocyte chemoattractant protein-1 induced by immobilized IgG, which would further reduce monocyte recruitment to the site of inflammation. In contrast, human alveolar macrophages were refractory to this effect, expressing low levels of TGF-beta type II receptors compared with peripheral blood monocytes from the same donor. These data provide insight into the regulation of immune responses by TGF-beta1 and demonstrate the selectivity of these effects.
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Affiliation(s)
- Susheela Tridandapani
- Department of Internal Medicine and Dorothy M. Davis Heart and Lung Research Institute, and The James Cancer Hospital and Comprehensive Cancer Center, Ohio State University, Columbus, OH 43210, USA.
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42
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Worth RG, Kim MK, Kindzelskii AL, Petty HR, Schreiber AD. Signal sequence within Fc gamma RIIA controls calcium wave propagation patterns: apparent role in phagolysosome fusion. Proc Natl Acad Sci U S A 2003; 100:4533-8. [PMID: 12676989 PMCID: PMC153590 DOI: 10.1073/pnas.0836650100] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2002] [Indexed: 11/18/2022] Open
Abstract
Calcium oscillations and traveling calcium waves have been observed in living cells, although amino acid sequences regulating wave directionality and downstream cell functions have not been reported. In this study we identify an amino acid sequence within the cytoplasmic domain of the leukocyte IgG receptor Fc gamma RIIA that affects the amplitude of calcium spikes and the spatiotemporal dynamics of calcium waves in the vicinity of phagosomes. By using high-speed microscopy to map calcium-signaling routes within cells, we have discovered that bound IgG-coated targets trigger two calcium waves traveling in opposite directions about the perimeter of cells expressing Fc gamma RIIA. After phagocytosis, one calcium wave propagates around the plasma membrane to the site of phagocytosis where it splits into two calcium signals: one traveling to and encircling the phagosome once, and the second continuing around the plasma membrane to the point of origin. However, in a genetically engineered form of Fc gamma RIIA containing a mutation in the cytoplasmic L-T-L motif, the calcium signal travels around the plasma membrane, but is not properly routed to the phagosome. Furthermore, these calcium pattern-deficient mutants were unable to support phagolysosome fusion, although recruitment of phagolysosome-associated proteins lysosome-associated protein 1, Rab5, and Rab7 were normal. Our findings suggest that: (i) calcium signaling is a late step in phagolysosome fusion, (ii) a line of communication exists between the plasma membrane and phagosome, and (iii) the L-T-L motif is a signal sequence for calcium signal routing to the phagosome.
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Affiliation(s)
- Randall G Worth
- Department of Medicine, University of Pennsylvania School of Medicine, Philadelphia, PA 19104, USA
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43
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Brdicka T, Imrich M, Angelisová P, Brdicková N, Horváth O, Spicka J, Hilgert I, Lusková P, Dráber P, Novák P, Engels N, Wienands J, Simeoni L, Osterreicher J, Aguado E, Malissen M, Schraven B, Horejsí V. Non-T cell activation linker (NTAL): a transmembrane adaptor protein involved in immunoreceptor signaling. J Exp Med 2002; 196:1617-26. [PMID: 12486104 PMCID: PMC2196071 DOI: 10.1084/jem.20021405] [Citation(s) in RCA: 167] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023] Open
Abstract
A key molecule necessary for activation of T lymphocytes through their antigen-specific T cell receptor (TCR) is the transmembrane adaptor protein LAT (linker for activation of T cells). Upon TCR engagement, LAT becomes rapidly tyrosine phosphorylated and then serves as a scaffold organizing a multicomponent complex that is indispensable for induction of further downstream steps of the signaling cascade. Here we describe the identification and preliminary characterization of a novel transmembrane adaptor protein that is structurally and evolutionarily related to LAT and is expressed in B lymphocytes, natural killer (NK) cells, monocytes, and mast cells but not in resting T lymphocytes. This novel transmembrane adaptor protein, termed NTAL (non-T cell activation linker) is the product of a previously identified WBSCR5 gene of so far unknown function. NTAL becomes rapidly tyrosine-phosphorylated upon cross-linking of the B cell receptor (BCR) or of high-affinity Fcgamma- and Fc epsilon -receptors of myeloid cells and then associates with the cytoplasmic signaling molecules Grb2, Sos1, Gab1, and c-Cbl. NTAL expressed in the LAT-deficient T cell line J.CaM2.5 becomes tyrosine phosphorylated and rescues activation of Erk1/2 and minimal transient elevation of cytoplasmic calcium level upon TCR/CD3 cross-linking. Thus, NTAL appears to be a structural and possibly also functional homologue of LAT in non-T cells.
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MESH Headings
- Adaptor Proteins, Signal Transducing
- Amino Acid Sequence
- Animals
- B-Lymphocytes/immunology
- B-Lymphocytes/metabolism
- Carrier Proteins/chemistry
- Carrier Proteins/genetics
- Carrier Proteins/isolation & purification
- Carrier Proteins/metabolism
- Cell Line
- Humans
- Killer Cells, Natural/immunology
- Killer Cells, Natural/metabolism
- Lymphocyte Activation
- Lymphoid Tissue/cytology
- Lymphoid Tissue/metabolism
- Membrane Microdomains/chemistry
- Membrane Microdomains/metabolism
- Membrane Proteins/chemistry
- Membrane Proteins/genetics
- Membrane Proteins/isolation & purification
- Membrane Proteins/metabolism
- Mice
- Mice, Inbred C57BL
- Mice, Knockout
- Molecular Sequence Data
- Monocytes/immunology
- Monocytes/metabolism
- Phosphoproteins/chemistry
- Phosphoproteins/genetics
- Phosphoproteins/isolation & purification
- Phosphoproteins/metabolism
- Phosphorylation
- Proteins
- Receptors, Antigen, B-Cell/metabolism
- Receptors, Fc/metabolism
- Receptors, IgE/metabolism
- Receptors, IgG/metabolism
- Signal Transduction
- T-Lymphocytes/immunology
- T-Lymphocytes/metabolism
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Affiliation(s)
- Tomás Brdicka
- Institute of Molecular Genetics, Academy of Sciences of the Czech Republic, Vídenská 1083, 142 20 Prague 4, Czech Republic
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44
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Wen R, Jou ST, Chen Y, Hoffmeyer A, Wang D. Phospholipase C gamma 2 is essential for specific functions of Fc epsilon R and Fc gamma R. JOURNAL OF IMMUNOLOGY (BALTIMORE, MD. : 1950) 2002; 169:6743-52. [PMID: 12471105 DOI: 10.4049/jimmunol.169.12.6743] [Citation(s) in RCA: 63] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Phospholipase Cgamma2 (PLCgamma2) plays a critical role in the functions of the B cell receptor in B cells and of the FcRgamma chain-containing collagen receptor in platelets. Here we report that PLCgamma2 is also expressed in mast cells and monocytes/macrophages and is activated by cross-linking of Fc(epsilon)R and Fc(gamma)R. Although PLCgamma2-deficient mice have normal development and numbers of mast cells and monocytes/macrophages, we demonstrate that PLCgamma2 is essential for specific functions of Fc(epsilon)R and Fc(gamma)R. While PLCgamma2-deficient mast cells have normal mitogen-activated protein kinase activation and cytokine production at mRNA levels, the mutant cells have impaired Fc(epsilon)R-mediated Ca(2+) flux and inositol 1,4,5-trisphosphate production, degranulation, and cytokine secretion. As a physiological consequence of the effect of PLCgamma2 deficiency, the mutant mice are resistant to IgE-mediated cutaneous inflammatory skin reaction. Macrophages from PLCgamma2-deficient mice have no detectable Fc(gamma)R-mediated Ca(2+) flux; however, the mutant cells have normal Fc(gamma)R-mediated phagocytosis. Moreover, PLCgamma2 plays a nonredundant role in Fc(gamma)R-mediated inflammatory skin reaction.
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MESH Headings
- Animals
- Biological Transport/genetics
- Biological Transport/immunology
- Calcium/metabolism
- Cations, Divalent/metabolism
- Cell Degranulation/genetics
- Cell Degranulation/immunology
- Cytokines/genetics
- Cytokines/metabolism
- Enzyme Activation/genetics
- Enzyme Activation/immunology
- Immunity, Innate/genetics
- Immunoglobulin E/physiology
- Isoenzymes/deficiency
- Isoenzymes/genetics
- Isoenzymes/physiology
- Macrophages, Peritoneal/enzymology
- Macrophages, Peritoneal/immunology
- Macrophages, Peritoneal/metabolism
- Mast Cells/enzymology
- Mast Cells/immunology
- Mast Cells/metabolism
- Mice
- Mice, Knockout
- Mitogen-Activated Protein Kinases/metabolism
- Passive Cutaneous Anaphylaxis
- Phagocytosis/genetics
- Phagocytosis/immunology
- Phospholipase C gamma
- Receptors, IgE/immunology
- Receptors, IgE/metabolism
- Receptors, IgE/physiology
- Receptors, IgG/immunology
- Receptors, IgG/metabolism
- Receptors, IgG/physiology
- Transcription, Genetic/immunology
- Type C Phospholipases/deficiency
- Type C Phospholipases/genetics
- Type C Phospholipases/physiology
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Affiliation(s)
- Renren Wen
- The Blood Research Institute, The Blood Center of Southeastern Wisconsin, Milwaukee, WI 53226, USA
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45
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Edberg JC, Qin H, Gibson AW, Yee AMF, Redecha PB, Indik ZK, Schreiber AD, Kimberly RP. The CY domain of the Fcgamma RIa alpha-chain (CD64) alters gamma-chain tyrosine-based signaling and phagocytosis. J Biol Chem 2002; 277:41287-93. [PMID: 12200451 DOI: 10.1074/jbc.m207835200] [Citation(s) in RCA: 20] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Although the cytoplasmic domain of the human FcgammaRIa alpha-chain lacks tyrosine-based phosphorylation motifs, it modulates receptor cycling and receptor-specific cytokine production. The cytoplasmic domain of FcgammaRIa is constitutively phosphorylated, and the inhibition of dephosphorylation with okadaic acid, an inhibitor of type 1 and type 2A protein serine/threonine phosphatase, inhibits both receptor-induced activation of the early tyrosine phosphorylation cascade and receptor-specific phagocytosis. To explore the basis for these effects of the cytoplasmic domain of FcgammaRIa, we developed a series of human FcgammaRIa molecular variants, expressed in the murine macrophage cell line P388D1, and demonstrate that serine phosphorylation of the cytoplasmic domain is an important regulatory mechanism. Truncation of the cytoplasmic domain and mutation of the cytoplasmic domain serine residues to alanine abolish the okadaic acid inhibition of phagocytic function. In contrast, the serine mutants did not recapitulate the selective effects of cytoplasmic domain truncation on cytokine production. These results demonstrate for the first time a direct functional role for serine phosphorylation in the alpha-chain of FcgammaRIa and suggest that the cytoplasmic domain of FcgammaRI regulates the different functional capacities of the FcgammaRIa-receptor complex.
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Affiliation(s)
- Jeffrey C Edberg
- Departments of Medicine and Microbiology, The University of Alabama at Birmingham, 1530 3rd Avenue S, THT433A, Birmingham, AL 35294, USA.
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46
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Tridandapani S, Wang Y, Marsh CB, Anderson CL. Src homology 2 domain-containing inositol polyphosphate phosphatase regulates NF-kappa B-mediated gene transcription by phagocytic Fc gamma Rs in human myeloid cells. JOURNAL OF IMMUNOLOGY (BALTIMORE, MD. : 1950) 2002; 169:4370-8. [PMID: 12370370 DOI: 10.4049/jimmunol.169.8.4370] [Citation(s) in RCA: 48] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
FcgammaR-mediated phagocytosis is accompanied by the generation of tissue-damaging products such as inflammatory cytokines and reactive oxygen species. Hence, the phagocytic response must be a tightly regulated process. Recent studies have established that clustering FcgammaR on human myeloid cells causes tyrosine phosphorylation of Src homology 2 domain-containing inositol polyphosphate phosphatase (SHIP). However, it is not known how these immunoreceptor tyrosine-based activation motif (ITAM)-bearing phagocytic FcgammaR activate SHIP, or whether the activation of SHIP by ITAMs has any functional relevance. Experiments addressing the mechanism of SHIP association with ITAMs have been done in in vitro systems using phosphopeptides. In this study we undertook to dissect the molecular mechanism by which SHIP associates with the native ITAM-FcgammaR and becomes phosphorylated. In this report we provide evidence that first, SHIP is indeed phosphorylated by ITAM-FcgammaR, using cell systems that lack FcgammaRIIb expression; second, coimmunoprecipitation experiments demonstrate that SHIP associates with native ITAM-bearing FcgammaRIIa in vivo; and third, phosphorylation of SHIP by FcgammaRIIa is inhibited by overexpressing either the SHIP Src homology 2 domain or a dominant negative mutant of Shc. In contrast, SHIP phosphorylation was not inhibited by a dominant negative mutant of Grb2. We extend these observations to show that SHIP activation by ITAM-FcgammaR down-regulates NF-kappaB-induced gene transcription. These findings both provide a molecular mechanism for SHIP association with native ITAM-bearing receptors and demonstrate that SHIP association with ITAM-FcgammaR serves to regulate gene expression during the phagocytic process.
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Affiliation(s)
- Susheela Tridandapani
- Department of Internal Medicine, Heart and Lung Research Institute, Room 405D, Ohio State University, 473 West Twelfth Avenue, Columbus, OH 43210, USA.
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47
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Abstract
The phagocytic response of innate immune cells such as macrophages is defined by the activation of complex signaling networks that are stimulated by microbial contact. Many individual proteins have been demonstrated to participate in phagocytosis, and the application of high-throughput tools has indicated that many more remain to be described. In this review, we examine this complexity and describe how during recognition, multiple receptors are simultaneously engaged to mediate internalization, activate microbial killing, and induce the production of inflammatory cytokines and chemokines. Many signaling molecules perform multiple functions during phagocytosis, and these molecules are likely to be key regulators of the process. Indeed, pathogenic microorganisms target many of these molecules in their attempts to evade destruction.
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Affiliation(s)
- David M Underhill
- Institute for Systems Biology, 1441 North 34 Street, Seattle, Washington 98103, USA.
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48
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Tridandapani S, Siefker K, Teillaud JL, Carter JE, Wewers MD, Anderson CL. Regulated expression and inhibitory function of Fcgamma RIIb in human monocytic cells. J Biol Chem 2002; 277:5082-9. [PMID: 11741917 DOI: 10.1074/jbc.m110277200] [Citation(s) in RCA: 114] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Human monocytes/macrophages express three classes of receptors for IgG: FcgammaRI, FcgammaRII, and FcgammaRIII. The expression and function of these receptors has been extensively studied with the exception of one, FcgammaRIIb. While the mRNA for FcgammaRIIb has been detected in human monocytes, the protein has remained elusive. Studies in mouse models indicated that the macrophage FcgammaRIIb serves to down-regulate FcgammaR-mediated phagocytosis and immune complex-induced inflammation. FcgammaRIIb has also been shown to modulate the action of cytotoxic antibodies against tumors in mouse models. Hence, an understanding of how FcgammaRIIb expression is regulated is of great importance. Here we demonstrate for the first time FcgammaRIIb protein expression and function in human monocytes. We also report that the expression of FcgammaRIIb is highly up-regulated by interleukin-4, a Th2 cytokine, and that the up-regulation of FcgammaRIIb results in a decrease in the phagocytic efficiency of interleukin-4-treated THP-1 cells. Furthermore co-clustering FcgammaRIIb with FcgammaRIIa resulted in enhanced phosphorylation of the inositol phosphatase SHIP, association of SHIP with Shc, and phosphorylation of additional proteins around 120 and 60-65 kDa, with a concomitant attenuation of Akt activation. We, therefore, propose that FcgammaRIIb serves to inhibit FcgammaRI/IIa-mediated macrophage activation using SHIP as its effector.
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Affiliation(s)
- Susheela Tridandapani
- Department of Internal Medicine, The Ohio State University, Columbus, Ohio 43210, USA
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49
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Abstract
Phagocytosis is an evolutionarily conserved process utilized by many cells to ingest microbial pathogens, and apoptotic and necrotic corpses. Recent investigation has revealed a fundamental requirement for two co-ordinated cellular processes--cytoskeletal alterations and membrane trafficking--in the phagocytic event. Some elements of this machinery are co-opted by certain pathogens to gain entry into host cells.
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Affiliation(s)
- Steven Greenberg
- Columbia University, Departments of Medicine and Pharmacology/BB914, 630 West 168th Street, New York, NY 10032, USA.
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50
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Coppolino MG, Krause M, Hagendorff P, Monner DA, Trimble W, Grinstein S, Wehland J, Sechi AS. Evidence for a molecular complex consisting of Fyb/SLAP, SLP-76, Nck, VASP and WASP that links the actin cytoskeleton to Fcγ receptor signalling during phagocytosis. J Cell Sci 2001; 114:4307-18. [PMID: 11739662 DOI: 10.1242/jcs.114.23.4307] [Citation(s) in RCA: 154] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Phagocytosis by macrophages and neutrophils involves the spatial and temporal reorganisation of the actin-based cytoskeleton at sites of particle ingestion. Local polymerisation of actin filaments supports the protrusion of pseudopodia that eventually engulf the particle. Here we have investigated in detail the cytoskeletal events initiated upon engagement of Fc receptors in macrophages. Ena/vasodilator-stimulated phosphoprotein (VASP) proteins were recruited to phagosomes forming around opsonised particles in both primary and immortalised macrophages. Not only did the localisation of Ena/VASP proteins coincide, spatially and temporally, with the phagocytosis-induced reorganisation of actin filaments, but their recruitment to the phagocytic cup was required for the remodelling of the actin cytoskeleton, extension of pseudopodia and efficient particle internalisation. We also report that SLP-76, Vav and profilin were recruited to forming phagosomes. Upon induction of phagocytosis, a large molecular complex, consisting in part of Ena/VASP proteins, the Fyn-binding/SLP-76-associated protein (Fyb/SLAP), Src-homology-2 (SH2)-domain-containing leukocyte protein of 76 kDa (SLP-76), Nck, and the Wiskott-Aldrich syndrome protein (WASP), was formed. Our findings suggest that activation of Fcγ receptors triggers two signalling events during phagocytosis: one through Fyb/SLAP that leads to recruitment of VASP and profilin; and another through Nck that promotes the recruitment of WASP. These converge to regulate actin polymerisation, controlling the assembly of actin structures that are essential for the process of phagocytosis.
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Affiliation(s)
- M G Coppolino
- Programme in Cell Biology, Research Institute, The Hospital for Sick Children, 555 University Avenue, Toronto, Ontario, M5G 1X8, Canada
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