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Hua T, Zhao BB, Fan SB, Zhao CF, Kong YH, Tian RQ, Zhang BY. Prognostic implications of PPL expression in ovarian cancer. Discov Oncol 2022; 13:35. [PMID: 35612641 PMCID: PMC9133299 DOI: 10.1007/s12672-022-00496-z] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/07/2022] [Accepted: 05/09/2022] [Indexed: 11/24/2022] Open
Abstract
Periplakin (PPL) is a main member in plakin family, which plays important role in cellular adhesion complexes supporting and cytoskeletal integrity supplying. PPL was reported to be a potential biomarker candidate for several types of cancers. However, the biological functions and underlying mechanisms of PPL in ovarian cancer (OV) remain unclear. In the present study, we used GEPIA 2, Human Protein Atlas, Oncomine, LinkedOmics, Kaplan-Meier Plotter, STRING, CytoHubba plug-in and TIMER to determine the associations among PPL expression, prognosis, and immune cell infiltration in OV. RT-qPCR and IHC analysis were conducted to validated the role of PPL in an independent OV cohort. Compared with the normal ovary tissues, the levels of PPL mRNA and protein expression were both obviously higher in OV tumors from multiple datasets (P < 0.05), and a poor survival was observed to be strongly correlated with high PPL expression (P < 0.05). Moreover, the results were further validated by RT-qPCR and IHC analysis in an independent OV cohort. A gene-clinical nomogram was constructed, including PPL mRNA expression and clinical factors in TCGA. Functional network analysis suggested that PPL participates in the important pathways like Wnt signaling pathway, MAPK signaling pathway. Ten hub genes (LAMC2, PXN, LAMA3, LAMB3, LAMA5, ITGA3, TLN1, ACTN4, ACTN1, and ITGB4) were identified to be positively associated with PPL. Furthermore, PPL expression was negatively correlated with infiltrating levels of CD4+ T cell, macrophages, neutrophils, and dendritic cells. In conclusion, PPL may be an unfavorable prognostic biomarker candidate in OV, which was also correlated with immune infiltrating and function in immunotherapy response.
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Affiliation(s)
- Tian Hua
- Department of Gynecology, Affiliated Xingtai People Hospital of Hebei Medial University, 16 Hongxing Road, Xingtai, 054001, Hebei, People's Republic of China.
| | - Bei-Bei Zhao
- Department of Gynecology, Affiliated Xingtai People Hospital of Hebei Medial University, 16 Hongxing Road, Xingtai, 054001, Hebei, People's Republic of China
| | - Shao-Bei Fan
- Department of Gynecology, Affiliated Xingtai People Hospital of Hebei Medial University, 16 Hongxing Road, Xingtai, 054001, Hebei, People's Republic of China
| | - Cai-Fen Zhao
- Department of Gynecology, Affiliated Xingtai People Hospital of Hebei Medial University, 16 Hongxing Road, Xingtai, 054001, Hebei, People's Republic of China
| | - Yun-Hong Kong
- Department of Gynecology, Affiliated Xingtai People Hospital of Hebei Medial University, 16 Hongxing Road, Xingtai, 054001, Hebei, People's Republic of China
| | - Rui-Qing Tian
- Department of Gynecology, Affiliated Xingtai People Hospital of Hebei Medial University, 16 Hongxing Road, Xingtai, 054001, Hebei, People's Republic of China
| | - Bao-Ying Zhang
- Department of Gynecology, Affiliated Xingtai People Hospital of Hebei Medial University, 16 Hongxing Road, Xingtai, 054001, Hebei, People's Republic of China
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2
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Wu J, Li Y, Rendahl A, Bhargava M. Novel Human FCGR1A Variants Affect CD64 Functions and Are Risk Factors for Sarcoidosis. Front Immunol 2022; 13:841099. [PMID: 35371020 PMCID: PMC8968912 DOI: 10.3389/fimmu.2022.841099] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2021] [Accepted: 02/24/2022] [Indexed: 12/19/2022] Open
Abstract
CD64 (or FcγRIA) is the sole functional high affinity IgG Fc receptor coded by FCGR1A gene in humans. The FCGR1A genetics has not been comprehensively investigated and effects of human FCGR1A variants on immune functions remain unknown. In the current study, we identified three novel FCGR1A variants including the single nucleotide variant (SNV) rs1848781 (c.-131) in the proximal FCGR1A gene promoter region, the rs587598788 indel variant within the FCGR1A intron 5, and the non-synonymous SNV rs1050204 (c.970G>A or FcγRIA-p.D324N) in the FCGR1A coding region. Genotype-phenotype analyses revealed that SNV rs1848781 genotypes were significantly associated with CD64 expression levels. Promoter reporter assays show that rs1848781G allele had significantly higher promoter activity than the rs1848781C, confirming that the rs1848781 is a functional FCGR1A SNV affecting promoter activity and gene expression. The rs587598788 indel genotypes were also significantly associated with levels of CD64 expression. Moreover, the non-synonymous SNV rs1050204 (FcγRIA-p.D324N) alleles significantly affected CD64-mediated phagocytosis, degranulation, and pro-inflammatory cytokine productions. Genetic analyses revealed that FCGR1A genotypes were significantly associated with sarcoidosis susceptibility and severity. Our data suggest that FCGR1A genetic variants may affect immune responses and play a role in sarcoidosis.
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Affiliation(s)
- Jianming Wu
- Department of Veterinary and Biomedical Sciences, College of Veterinary Medicine, University of Minnesota, St. Paul, MN, United States
- *Correspondence: Jianming Wu, ; orcid.org/000-0001-9142-7066
| | - Yunfang Li
- Department of Veterinary and Biomedical Sciences, College of Veterinary Medicine, University of Minnesota, St. Paul, MN, United States
| | - Aaron Rendahl
- Department of Veterinary and Biomedical Sciences, College of Veterinary Medicine, University of Minnesota, St. Paul, MN, United States
| | - Maneesh Bhargava
- Division of Pulmonary, Allergy, Critical Care & Sleep Medicine, Department of Medicine, School of Medicine, University of Minnesota, Minneapolis, MN, United States
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3
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Wesley T, Berzins S, Kannourakis G, Ahmed N. The attributes of plakins in cancer and disease: perspectives on ovarian cancer progression, chemoresistance and recurrence. Cell Commun Signal 2021; 19:55. [PMID: 34001250 PMCID: PMC8127266 DOI: 10.1186/s12964-021-00726-x] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2020] [Accepted: 02/20/2021] [Indexed: 02/06/2023] Open
Abstract
The plakin family of cytoskeletal proteins play an important role in cancer progression yet are under-studied in cancer, especially ovarian cancer. These large cytoskeletal proteins have primary roles in the maintenance of cytoskeletal integrity but are also associated with scaffolds of intermediate filaments and hemidesmosomal adhesion complexes mediating signalling pathways that regulate cellular growth, migration, invasion and differentiation as well as stress response. Abnormalities of plakins, and the closely related spectraplakins, result in diseases of the skin, striated muscle and nervous tissue. Their prevalence in epithelial cells suggests that plakins may play a role in epithelial ovarian cancer progression and recurrence. In this review article, we explore the roles of plakins, particularly plectin, periplakin and envoplakin in disease-states and cancers with emphasis on ovarian cancer. We discuss the potential role the plakin family of proteins play in regulating cancer cell growth, survival, migration, invasion and drug resistance. We highlight potential relationships between plakins, epithelial-mesenchymal transition (EMT) and cancer stem cells (CSCs) and discuss how interaction of these processes may affect ovarian cancer progression, chemoresistance and ultimately recurrence. We propose that molecular changes in the expression of plakins leads to the transition of benign ovarian tumours to carcinomas, as well as floating cellular aggregates (commonly known as spheroids) in the ascites microenvironment, which may contribute to the sustenance and progression of the disease. In this review, attempts have been made to understand the crucial changes in plakin expression in relation to progression and recurrence of ovarian cancer. Video Abstract
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Affiliation(s)
- Tamsin Wesley
- Fiona Elsey Cancer Research Institute, Ballarat Technology Central Park, Suites 23-26, 106-110 Lydiard Street South, Ballarat, VIC, 3353, Australia.,School of Science, Psychology and Sport, Federation University Australia, Ballarat, VIC, 3010, Australia
| | - Stuart Berzins
- Fiona Elsey Cancer Research Institute, Ballarat Technology Central Park, Suites 23-26, 106-110 Lydiard Street South, Ballarat, VIC, 3353, Australia.,School of Science, Psychology and Sport, Federation University Australia, Ballarat, VIC, 3010, Australia
| | - George Kannourakis
- Fiona Elsey Cancer Research Institute, Ballarat Technology Central Park, Suites 23-26, 106-110 Lydiard Street South, Ballarat, VIC, 3353, Australia.,School of Science, Psychology and Sport, Federation University Australia, Ballarat, VIC, 3010, Australia
| | - Nuzhat Ahmed
- Fiona Elsey Cancer Research Institute, Ballarat Technology Central Park, Suites 23-26, 106-110 Lydiard Street South, Ballarat, VIC, 3353, Australia. .,School of Science, Psychology and Sport, Federation University Australia, Ballarat, VIC, 3010, Australia. .,Department of Obstetrics and Gynaecology, University of Melbourne, Melbourne, VIC, 3052, Australia. .,Centre for Reproductive Health, The Hudson Institute of Medical Research and Department of Translational Medicine, Monash University, Melbourne, VIC, 3168, Australia.
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4
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Abstract
Receptors recognizing the Fc-part of immunoglobulins (FcR) are important in the engagement of phagocytes with opsonized micro-organisms, but they also play a major role in the pathogenesis of chronic inflammatory diseases. Different FcRs are specifically recognizing and binding the different classes of immunoglobulins, transmitting different signals into the cell. The function of IgG (FcγR's) and IgA (FcαR) recognizing receptors is controlled by cellular signals evoked by activation of heterologous receptors in a process generally referred to as inside-out control. This concept is clearly described for the regulation of integrin receptors. Inside-out control can be achieved at different levels by modulation of: (i) receptor affinity, (ii) receptor avidity/valency, (iii) interaction with signaling chains, (iv) interaction with other receptors and (v) localization in functionally different membrane domains. The inside-out control of FcRs is an interesting target for novel therapy by therapeutical antibodies as it can potentiate or decrease the functionality of the response to the antibodies depending on the mechanisms of the diseases they are applied for.
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Affiliation(s)
- Leo Koenderman
- Department of Respiratory Medicine and Laboratory of Translational Immunology, University Medical Center Utrecht, Utrecht, Netherlands
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5
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Gujrati M, Mittal R, Ekal L, Mishra RK. SUMOylation of periplakin is critical for efficient reorganization of keratin filament network. Mol Biol Cell 2018; 30:357-369. [PMID: 30516430 PMCID: PMC6589569 DOI: 10.1091/mbc.e18-04-0244] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023] Open
Abstract
The architecture of the cytoskeleton and its remodeling are tightly regulated by dynamic reorganization of keratin-rich intermediate filaments. Plakin family proteins associate with the network of intermediate filaments (IFs) and affect its reorganization during migration, differentiation, and response to stress. The smallest plakin, periplakin (PPL), interacts specifically with intermediate filament proteins K8, K18, and vimentin via its C-terminal linker domain. Here, we show that periplakin is SUMOylated at a conserved lysine in its linker domain (K1646) preferentially by small ubiquitin-like modifier 1 (SUMO1). Our data indicate that PPL SUMOylation is essential for the proper reorganization of the keratin IF network. Stresses perturbing intermediate-filament and cytoskeletal architecture induce hyper--SUMOylation of periplakin. Okadaic acid induced hyperphosphorylation-dependent collapse of the keratin IF network results in a similar hyper-SUMOylation of PPL. Strikingly, exogenous overexpression of a non-SUMOylatable periplakin mutant (K1646R) induced aberrant bundling and loose network interconnections of the keratin filaments. Time-lapse imaging of cells expressing the K1646R mutant showed the enhanced sensitivity of keratin filament collapse upon okadaic acid treatment. Our data identify an important regulatory role for periplakin SUMOylation in dynamic reorganization and stability of keratin IFs.
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Affiliation(s)
- Mansi Gujrati
- Nups and SUMO Biology Group, Department of Biological Sciences, Indian Institute of Science Education and Research (IISER) Bhopal, Madhya Pradesh 462066, India
| | - Rohit Mittal
- MRC Laboratory of Molecular Biology, Cambridge CB2 0QH, UK
| | - Lakhan Ekal
- Department of Molecular Biology and Biotechnology, University of Sheffield, Sheffield S10 2TN, UK
| | - Ram Kumar Mishra
- Nups and SUMO Biology Group, Department of Biological Sciences, Indian Institute of Science Education and Research (IISER) Bhopal, Madhya Pradesh 462066, India
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6
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Brandsma AM, Schwartz SL, Wester MJ, Valley CC, Blezer GLA, Vidarsson G, Lidke KA, Ten Broeke T, Lidke DS, Leusen JHW. Mechanisms of inside-out signaling of the high-affinity IgG receptor FcγRI. Sci Signal 2018; 11:11/540/eaaq0891. [PMID: 30042128 DOI: 10.1126/scisignal.aaq0891] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Fc receptors (FcRs) are an important bridge between the innate and adaptive immune system. Fc gamma receptor I (FcγRI; CD64), the high-affinity receptor for immunoglobulin G (IgG), plays roles in inflammation, autoimmune responses, and immunotherapy. Stimulation of myeloid cells with cytokines, such as tumor necrosis factor-α ( TNFα) and interferon-γ ( IFNγ), increases the binding of FcγRI to immune complexes (ICs), such as antibody-opsonized pathogens or tumor cells, through a process known as "inside-out" signaling. Using super-resolution imaging, we found that stimulation of cells with IL-3 also enhanced the clustering of FcγRI both before and after exposure to ICs. This increased clustering was dependent on an intact actin cytoskeleton. We found that chemical inhibition of the activity of the phosphatase PP1 reduced FcγRI inside-out signaling, although the phosphorylation of FcγRI itself was unaffected. Furthermore, the antibody-dependent cytotoxic activity of human neutrophils toward CD20-expressing tumor cells was increased after stimulation with TNFα and IFNγ. These results suggest that nanoscale reorganization of FcγRI, stimulated by cytokine-induced, inside-out signaling, enhances FcγRI cellular effector functions.
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Affiliation(s)
- Arianne M Brandsma
- Immunotherapy Laboratory, Laboratory for Translational Immunology, University Medical Center Utrecht, Utrecht, Netherlands
| | - Samantha L Schwartz
- Department of Pathology and Comprehensive Cancer Center, University of New Mexico, Albuquerque, NM 87102, USA
| | - Michael J Wester
- Department of Pathology and Comprehensive Cancer Center, University of New Mexico, Albuquerque, NM 87102, USA
| | - Christopher C Valley
- Department of Pathology and Comprehensive Cancer Center, University of New Mexico, Albuquerque, NM 87102, USA
| | - Gittan L A Blezer
- Immunotherapy Laboratory, Laboratory for Translational Immunology, University Medical Center Utrecht, Utrecht, Netherlands
| | - Gestur Vidarsson
- Sanquin Research and Landsteiner Laboratory, Department of Experimental Hematology, Academic Medical Center, University of Amsterdam, Amsterdam, Netherlands
| | - Keith A Lidke
- Department of Physics and Astronomy, University of New Mexico, Albuquerque, NM 87131, USA
| | - Toine Ten Broeke
- Immunotherapy Laboratory, Laboratory for Translational Immunology, University Medical Center Utrecht, Utrecht, Netherlands
| | - Diane S Lidke
- Department of Pathology and Comprehensive Cancer Center, University of New Mexico, Albuquerque, NM 87102, USA
| | - Jeanette H W Leusen
- Immunotherapy Laboratory, Laboratory for Translational Immunology, University Medical Center Utrecht, Utrecht, Netherlands.
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7
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Besnard V, Dagher R, Madjer T, Joannes A, Jaillet M, Kolb M, Bonniaud P, Murray LA, Sleeman MA, Crestani B. Identification of periplakin as a major regulator of lung injury and repair in mice. JCI Insight 2018. [PMID: 29515024 DOI: 10.1172/jci.insight.90163] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
Periplakin is a component of the desmosomes that acts as a cytolinker between intermediate filament scaffolding and the desmosomal plaque. Periplakin is strongly expressed by epithelial cells in the lung and is a target antigen for autoimmunity in idiopathic pulmonary fibrosis. The aim of this study was to determine the role of periplakin during lung injury and remodeling in a mouse model of lung fibrosis induced by bleomycin. We found that periplakin expression was downregulated in the whole lung and in alveolar epithelial cells following bleomycin-induced injury. Deletion of the Ppl gene in mice improved survival and reduced lung fibrosis development after bleomycin-induced injury. Notably, Ppl deletion promoted an antiinflammatory alveolar environment linked to profound changes in type 2 alveolar epithelial cells, including overexpression of antiinflammatory cytokines, decreased expression of profibrotic mediators, and altered cell signaling with a reduced response to TGF-β1. These results identify periplakin as a previously unidentified regulator of the response to injury in the lung.
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Affiliation(s)
| | | | | | | | | | - Martin Kolb
- Department of Medecine, Firestone Institute for respiratory Health, McMaster University and The Research Institute of St. Joe's Hamilton, Hamilton, Canada
| | | | - Lynne A Murray
- MedImmune Ltd, Granta Park, Cambridgeshire, United Kingdom.,Respiratory, Inflammation, Autoimmunity (RIA) IMED Biotech unit, AstraZeneca, Gothenburg, Sweden
| | | | - Bruno Crestani
- INSERM U1152, Paris, France.,Université Paris Diderot, LABEX INFLAMEX, Paris, France.,Assistance Publique-Hôpitaux de Paris, DHU FIRE, Hôpital Bichat, Paris, France
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8
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Swisher JFA, Feldman GM. The many faces of FcγRI: implications for therapeutic antibody function. Immunol Rev 2016; 268:160-74. [PMID: 26497519 DOI: 10.1111/imr.12334] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Fcγ receptor I (FcγRI or CD64) is the sole human Fc receptor with high affinity for monovalent IgG. While it contains an immunoreceptor tyrosine-based activation motif in its cytoplasmic domain, binding of FcγRI can result in a complex array of activating and inhibitory outcomes. For instance, binding of monomeric IgG provides a low-intensity tonic signal through FcγRI that is necessary for full interferon γ receptor signaling in the same cell. Interaction of FcγRI with larger high-avidity complexes can result in phagocytosis, the generation of reactive oxygen species, as well as the synthesis and release of inflammatory cytokines. However, numerous reports also document potent anti-inflammatory effects brought about by FcγRI engagement with immune complexes such as the inhibition of IFNγ and TLR4 signaling, and secretion of interleukin-10. This has led to conflicting hypotheses regarding the function of FcγRI, especially with regard to its role in the efficacy of several therapeutic monoclonal antibodies. While many of these issues are still unclear, continued characterization of the regulation and context dependence of FcγRI function, as well as the molecular mechanisms responsible for these various outcomes, will improve our understanding of FcγRI biology as well as the therapeutic strategies designed to harness or constrain its actions.
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Affiliation(s)
- Jennifer F A Swisher
- Laboratory of Immunobiology, Division of Biotechnology Research and Review IV, Office of Biotechnology Products, Center for Drug Evaluation and Research, Food and Drug Administration, Silver Spring, MD, USA
| | - Gerald M Feldman
- Laboratory of Immunobiology, Division of Biotechnology Research and Review IV, Office of Biotechnology Products, Center for Drug Evaluation and Research, Food and Drug Administration, Silver Spring, MD, USA
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9
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Affiliation(s)
- David A. Rhodes
- Department of Pathology, Immunology Division, University of Cambridge, Cambridge Institute for Medical Research, Cambridge CB2 0XY, United Kingdom; ,
| | - Walter Reith
- Department of Pathology and Immunology, Faculty of Medicine, University of Geneva, CH-1211 Geneva 4, Switzerland;
| | - John Trowsdale
- Department of Pathology, Immunology Division, University of Cambridge, Cambridge Institute for Medical Research, Cambridge CB2 0XY, United Kingdom; ,
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10
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Brandsma AM, Jacobino SR, Meyer S, ten Broeke T, Leusen JHW. Fc receptor inside-out signaling and possible impact on antibody therapy. Immunol Rev 2015; 268:74-87. [DOI: 10.1111/imr.12332] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Affiliation(s)
- Arianne M. Brandsma
- Immunotherapy Laboratory; Laboratory for Translational Immunology; UMC Utrecht; Utrecht The Netherlands
| | - Shamir R. Jacobino
- Immunotherapy Laboratory; Laboratory for Translational Immunology; UMC Utrecht; Utrecht The Netherlands
| | - Saskia Meyer
- Immunotherapy Laboratory; Laboratory for Translational Immunology; UMC Utrecht; Utrecht The Netherlands
| | - Toine ten Broeke
- Immunotherapy Laboratory; Laboratory for Translational Immunology; UMC Utrecht; Utrecht The Netherlands
| | - Jeanette H. W. Leusen
- Immunotherapy Laboratory; Laboratory for Translational Immunology; UMC Utrecht; Utrecht The Netherlands
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11
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Chenoweth AM, Trist HM, Tan PS, Wines BD, Hogarth PM. The high-affinity receptor for IgG, FcγRI, of humans and non-human primates. Immunol Rev 2015; 268:175-91. [DOI: 10.1111/imr.12366] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Affiliation(s)
- Alicia M. Chenoweth
- Centre for Biomedicine; Burnet Institute; Melbourne Vic. Australia
- Department of Immunology; Monash University; Melbourne Vic. Australia
| | - Halina M. Trist
- Centre for Biomedicine; Burnet Institute; Melbourne Vic. Australia
| | - Peck-Szee Tan
- Centre for Biomedicine; Burnet Institute; Melbourne Vic. Australia
| | - Bruce D. Wines
- Centre for Biomedicine; Burnet Institute; Melbourne Vic. Australia
- Department of Immunology; Monash University; Melbourne Vic. Australia
- Department of Pathology; University of Melbourne; Melbourne Vic. Australia
| | - P. Mark Hogarth
- Centre for Biomedicine; Burnet Institute; Melbourne Vic. Australia
- Department of Immunology; Monash University; Melbourne Vic. Australia
- Department of Pathology; University of Melbourne; Melbourne Vic. Australia
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12
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Functional Analysis of Periplakin and Envoplakin, Cytoskeletal Linkers, and Cornified Envelope Precursor Proteins. Methods Enzymol 2015; 569:309-29. [PMID: 26778565 DOI: 10.1016/bs.mie.2015.06.019] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
Envoplakin and periplakin are the two smallest plakin family cytoskeletal linker proteins that connect intermediate filaments to cellular junctions and other membrane locations. These two plakins have a structural role in the assembly of the cornified envelope (CE), the terminal stage of epidermal differentiation. Analysis of gene-targeted mice lacking both these plakins and the third initial CE scaffold protein, involucrin, demonstrate the importance of the structural integrity of CE for a proper epidermal barrier function. It has emerged that periplakin, which also has a wider tissue distribution than envoplakin, has additional, independent roles. Periplakin participates in the cytoskeletal organization also in other tissues and interacts with a wide range of membrane-associated proteins such as kazrin and butyrophilin BTN3A1. This review covers methods used to understand periplakin and envoplakin functions in cell culture models, including siRNA ablation of periplakin expression and the use of tagged protein domain constructs to study localization and interactions. In addition, assays that can be used to analyze CEs and epidermal barrier function in gene-targeted mice are described and discussed.
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13
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Abstract
The capacity of immunoglobulin G (IgG) antibodies to eliminate virtually any target cell has resulted in the widespread introduction of cytotoxic antibodies into the clinic in settings of cancer therapy, autoimmunity, and transplantation, for example. More recently, it has become apparent that also the protection from viral infection via IgG antibodies may require cytotoxic effector functions, suggesting that antibody-dependent cellular cytotoxicity (ADCC) directed against malignant or virally infected cells is one of the most essential effector mechanisms triggered by IgG antibodies to protect the host. A detailed understanding of the underlying molecular and cellular pathways is critical, therefore, to make full use of this antibody effector function. Several studies over the last years have provided novel insights into the effector pathways and innate immune effector cells responsible for ADCC reactions. One of the most notable outcomes of many of these reports is that cells of the mononuclear phagocytic system rather than natural killer cells are critical for removal of IgG opsonized target cells in vivo.
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14
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Zhou J, Zhu Z, Bai C, Sun H, Wang X. Proteomic profiling of lymphocytes in autoimmunity, inflammation and cancer. J Transl Med 2014; 12:6. [PMID: 24397796 PMCID: PMC3895788 DOI: 10.1186/1479-5876-12-6] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2013] [Accepted: 01/04/2014] [Indexed: 11/10/2022] Open
Abstract
Lymphocytes play important roles in the balance between body defense and noxious agents involved in a number of diseases, e.g. autoimmune diseases, allergic inflammation and cancer. The proteomic analyses have been applied to identify and validate disease-associated and disease-specific biomarkers for therapeutic strategies of diseases. The proteomic profiles of lymphocytes may provide more information to understand their functions and roles in the development of diseases, although proteomic approaches in lymphocytes are still limited. The present review overviewed the proteomics-based studies on lymphocytes to headlight the proteomic profiles of lymphocytes in diseases, such as autoimmune diseases, allergic inflammation and cancer, with a special focus on lung diseases. We will explore the potential significance of diagnostic biomarkers and therapeutic targets from the current status in proteomic studies of lymphocytes and discuss the value of the currently available proteomic methodologies in the lymphocytes research.
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Affiliation(s)
| | | | | | - Hongzhi Sun
- Department of Pulmonary Medicine, Zhongshan Hospital, Fudan University, Shanghai Medical College, Shanghai, China.
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15
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Ito S, Satoh J, Matsubara T, Shah YM, Ahn SH, Anderson CR, Shan W, Peters JM, Gonzalez FJ. Cholestasis induces reversible accumulation of periplakin in mouse liver. BMC Gastroenterol 2013; 13:116. [PMID: 23849208 PMCID: PMC3716950 DOI: 10.1186/1471-230x-13-116] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/04/2013] [Accepted: 07/12/2013] [Indexed: 12/16/2022] Open
Abstract
BACKGROUND Periplakin (PPL) is a rod-shaped cytolinker protein thought to connect cellular adhesion junctional complexes to cytoskeletal filaments. PPL serves as a structural component of the cornified envelope in the skin and interacts with various types of proteins in cultured cells; its level decreases dramatically during tumorigenic progression in human epithelial tissues. Despite these intriguing observations, the physiological roles of PPL, especially in non-cutaneous tissues, are still largely unknown. Because we observed a marked fluctuation of PPL expression in mouse liver in association with the bile acid receptor farnesoid X receptor (FXR) and cholestasis, we sought to characterize the role of PPL in the liver and determine its contributions to the etiology and pathogenesis of cholestasis. METHODS Time- and context-dependent expression of PPL in various mouse models of hepatic and renal disorders were examined by immunohistochemistry, western blotting, and quantitative real-time polymerase chain reactions. RESULTS The hepatic expression of PPL was significantly decreased in Fxr-/- mice. In contrast, the expression was dramatically increased during cholestasis, with massive PPL accumulation observed at the boundaries of hepatocytes in wild-type mice. Interestingly, the hepatic accumulation of PPL resulting from cholestasis was reversible. In addition, similar accumulation of PPL at cellular boundaries was found in epithelial cells around renal tubules upon ureteral obstruction. CONCLUSIONS PPL may be involved in the temporal accommodation to fluid stasis in different tissues. Further examination of the roles for PPL may lead to the discovery of a novel mechanism for cellular protection by cytolinkers that is applicable to many tissues and in many contexts.
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Affiliation(s)
- Shinji Ito
- Biofrontier Platform, Graduate School of Medicine, Kyoto University, Yoshida Konoe-cho, Sakyo-ku, Kyoto 606-8501, Japan.
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16
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Cross-presentation of IgG-containing immune complexes. Cell Mol Life Sci 2012; 70:1319-34. [PMID: 22847331 DOI: 10.1007/s00018-012-1100-8] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2012] [Revised: 07/09/2012] [Accepted: 07/17/2012] [Indexed: 12/23/2022]
Abstract
IgG is a molecule that functionally combines facets of both innate and adaptive immunity and therefore bridges both arms of the immune system. On the one hand, IgG is created by adaptive immune cells, but can be generated by B cells independently of T cell help. On the other hand, once secreted, IgG can rapidly deliver antigens into intracellular processing pathways, which enable efficient priming of T cell responses towards epitopes from the cognate antigen initially bound by the IgG. While this process has long been known to participate in CD4(+) T cell activation, IgG-mediated delivery of exogenous antigens into a major histocompatibility complex (MHC) class I processing pathway has received less attention. The coordinated engagement of IgG with IgG receptors expressed on the cell-surface (FcγR) and within the endolysosomal system (FcRn) is a highly potent means to deliver antigen into processing pathways that promote cross-presentation of MHC class I and presentation of MHC class II-restricted epitopes within the same dendritic cell. This review focuses on the mechanisms by which IgG-containing immune complexes mediate such cross-presentation and the implications that this understanding has for manipulation of immune-mediated diseases that depend upon or are due to the activities of CD8(+) T cells.
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Gibson AW, Li X, Wu J, Baskin JG, Raman C, Edberg JC, Kimberly RP. Serine phosphorylation of FcγRI cytoplasmic domain directs lipid raft localization and interaction with protein 4.1G. J Leukoc Biol 2011; 91:97-103. [PMID: 22003208 DOI: 10.1189/jlb.0711368] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
The high-affinity IgG receptor (CD64, FcγRI) has several special capacities, including the receptor-stimulated cleavage of the cell surface B cell-activating factor of the TNF superfamily (TNFSF13B). With the use of the yeast two-hybrid system, we and others have shown that FcγRI interacts with protein 4.1G (EPB41L2). Our mutational analyses identified two required 4.1G-interacting regions in the FcγRI CY and one FcγRI-interacting site in the C-terminus of protein 4.1G. Herein, we explore mechanism(s) that may regulate the interaction between protein 4.1G and FcγRI CY and influence FcγRI membrane mobility and function. We show that FcγRI CY interacts with protein 4.1G in vitro and that FcγRI coimmunoprecipitates protein 4.1G in freshly isolated human PBMC. With the use of immunostaining, we show that FcγRI colocalizes with protein 4.1G in unstimulated U937 cells, in which the FcγRI CY is constitutively serine-phosphorylated, but significant uncoupling occurs following FcγRI cross-linking, suggesting phosphoserine-regulated interaction. In vitro, protein 4.1G interacted preferentially with CK2-phosphorylated FcγRI CY, and compared with WT FcγRI, a nonphosphorylatable FcγRI mutant receptor was excluded from lipid rafts, suggesting a key role for protein 4.1G in targeting phosphorylated FcγRI to rafts. These data are consistent with a phosphoserine-dependent tethering role for protein 4.1G in maintaining FcγRI in lipid rafts and provide insight into the unique phosphoserine-based regulation of receptor signaling by FcγRI CY.
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Affiliation(s)
- Andrew W Gibson
- Department of Medicine, University of Alabama at Birmingham, Birmingham, Alabama 35294, USA.
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Syntenin-mediated regulation of Sox4 proteasomal degradation modulates transcriptional output. Oncogene 2011; 31:2668-79. [PMID: 21986941 DOI: 10.1038/onc.2011.445] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
The transcription factor Sox4 is aberrantly expressed in many human tumors and can modulate tumorigenesis and metastases of murine tumors in vivo. However, mechanisms that control Sox4 function remain poorly defined. It has recently been observed that DNA damage increases Sox4 protein expression independently of Sox4 mRNA levels, suggesting an as yet undefined post-transcriptional mechanism regulating Sox4 expression and functionality. Here, we show that Sox4 protein is rapidly degraded by the proteasome as indicated by pharmacological inhibition with Mg132 and epoxymycin. Sox4 half-life was found to be less than 1 h as evident by inhibition of protein synthesis using cycloheximide. Ectopic expression of Sox4 deletion mutants revealed that the C-terminal 33 residues of Sox4 were critical in modulating its degradation in a polyubiquitin-independent manner. Syntenin, a Sox4 binding partner, associates with this domain and was found to stabilize Sox4 expression. Syntenin-induced stabilization of Sox4 correlated with Sox4-syntenin relocalization to the nucleus, where both proteins accumulate. Syntenin overexpression or knockdown in human tumor cell lines was found to reciprocally modulate Sox4 protein expression and transcriptional activity implicating its role as a regulator of Sox4. Taken together, our data demonstrate that the Sox4 C-terminal domain regulates polyubiquitin-independent proteasomal degradation of Sox4 that can be modulated by interaction with syntenin. As aberrant Sox4 expression has been found associated with many human cancers, modulation of Sox4 proteasomal degradation may impact oncogenesis and metastatic properties of tumors.
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Gardiner J, Overall R, Marc J. Putative Arabidopsishomologues of metazoan coiled-coil cytoskeletal proteins. Cell Biol Int 2011; 35:767-774. [DOI: 10.1042/cbi20100719] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 08/30/2023]
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21
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Cytokine-induced immune complex binding to the high-affinity IgG receptor, FcγRI, in the presence of monomeric IgG. Blood 2010; 116:5327-33. [DOI: 10.1182/blood-2010-04-280214] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023] Open
Abstract
Abstract
FcγRI is the sole high-affinity immunoglobulin G (IgG) receptor on leukocytes. Its role in immunity and the clearance of opsonized particles has been challenged, as the receptor function may well be hindered by serum IgG. Here, we document immune complex binding by FcγRI to be readily enhanced by cytokine stimulation, whereas binding of monomeric IgG only modestly increased. Enhanced immune complex binding was independent of FcγRI surface expression levels. FcγRI, saturated with prebound IgG, was found capable of effective immune complex binding upon cytokine stimulation. Cytokine-enhanced binding was observed across a variety of immune complexes, including huIgG3- or mIgG2a-opsonized red blood cells, rituximab- or ofatumumab-opsonized B-cell lymphoma, and cetuximab-opsonized glioblastoma cells. This study contributes to our understanding of how FcγRI can participate in the clearance of opsonized particles despite saturation by monomeric IgG.
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22
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Mittal R, Sukumaran SK, Selvaraj SK, Wooster DG, Babu MM, Schreiber AD, Verbeek JS, Prasadarao NV. Fcγ receptor I alpha chain (CD64) expression in macrophages is critical for the onset of meningitis by Escherichia coli K1. PLoS Pathog 2010; 6:e1001203. [PMID: 21124939 PMCID: PMC2987830 DOI: 10.1371/journal.ppat.1001203] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2010] [Accepted: 10/21/2010] [Indexed: 11/18/2022] Open
Abstract
Neonatal meningitis due to Escherichia coli K1 is a serious illness with unchanged morbidity and mortality rates for the last few decades. The lack of a comprehensive understanding of the mechanisms involved in the development of meningitis contributes to this poor outcome. Here, we demonstrate that depletion of macrophages in newborn mice renders the animals resistant to E. coli K1 induced meningitis. The entry of E. coli K1 into macrophages requires the interaction of outer membrane protein A (OmpA) of E. coli K1 with the alpha chain of Fcγ receptor I (FcγRIa, CD64) for which IgG opsonization is not necessary. Overexpression of full-length but not C-terminal truncated FcγRIa in COS-1 cells permits E. coli K1 to enter the cells. Moreover, OmpA binding to FcγRIa prevents the recruitment of the γ-chain and induces a different pattern of tyrosine phosphorylation of macrophage proteins compared to IgG2a induced phosphorylation. Of note, FcγRIa−/− mice are resistant to E. coli infection due to accelerated clearance of bacteria from circulation, which in turn was the result of increased expression of CR3 on macrophages. Reintroduction of human FcγRIa in mouse FcγRIa−/− macrophages in vitro increased bacterial survival by suppressing the expression of CR3. Adoptive transfer of wild type macrophages into FcγRIa−/− mice restored susceptibility to E. coli infection. Together, these results show that the interaction of FcγRI alpha chain with OmpA plays a key role in the development of neonatal meningitis by E. coli K1. Escherichia coli K1 is the most common cause of meningitis in premature infants; the mortality rate of this disease ranges from 5% to 30%. A better understanding of the pathogenesis of E. coli K1 meningitis is needed to develop new preventative strategies. We have shown that outer membrane protein A (OmpA) of E. coli K1, independent of antibody opsonization, is critical for bacterial entrance and survival within macrophages. Using a newborn mouse model, we found that depletion of macrophages renders the animals resistant to E. coli K1 induced meningitis. OmpA binds to α-chain of Fcγ-receptor I (FcγRIa) in macrophages, but does not induce expected gamma chain association and signaling. FcγRIa knockout mice are resistant to E. coli K1 infection because their macrophages express more CR3 and are thus able to kill bacteria with greater efficiency, preventing the development of high-grade bacteremia, a pre-requisite for the onset of meningitis. These novel observations demonstrate that inhibiting OmpA binding to FcγRIa is a promising therapeutic target for treatment or prevention of neonatal meningitis.
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MESH Headings
- Animals
- Animals, Newborn
- Bacterial Outer Membrane Proteins/metabolism
- Binding, Competitive
- Blotting, Western
- Brain/immunology
- Brain/metabolism
- Brain/microbiology
- COS Cells
- Chlorocebus aethiops
- Escherichia coli/growth & development
- Escherichia coli/pathogenicity
- Flow Cytometry
- Humans
- Immunoglobulin G/immunology
- Immunoglobulin G/metabolism
- Immunoprecipitation
- Macrophage-1 Antigen/metabolism
- Macrophages/immunology
- Macrophages/metabolism
- Macrophages/microbiology
- Meningitis, Escherichia coli/etiology
- Meningitis, Escherichia coli/metabolism
- Meningitis, Escherichia coli/pathology
- Mice
- Mice, Inbred C57BL
- Mice, Knockout
- Nitric Oxide/metabolism
- Phagocytosis
- Phosphorylation
- RNA, Messenger/genetics
- Receptors, IgG/physiology
- Reverse Transcriptase Polymerase Chain Reaction
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Affiliation(s)
- Rahul Mittal
- Division of Infectious Diseases, The Saban Research Institute, Childrens Hospital Los Angeles, Los Angeles, California, United States of America
| | - Sunil K. Sukumaran
- Division of Infectious Diseases, The Saban Research Institute, Childrens Hospital Los Angeles, Los Angeles, California, United States of America
| | - Suresh K. Selvaraj
- Division of Infectious Diseases, The Saban Research Institute, Childrens Hospital Los Angeles, Los Angeles, California, United States of America
| | - David G. Wooster
- Division of Infectious Diseases, The Saban Research Institute, Childrens Hospital Los Angeles, Los Angeles, California, United States of America
| | - M. Madan Babu
- Structural Studies Division, Medical Research Council, Laboratory of Molecular Biology, Cambridge, United Kingdom
| | - Alan D. Schreiber
- Hematology and Oncology Division, University of Pennsylvania School of Medicine, Philadelphia, Pennsylvania, United States of America
| | - J. Sjef Verbeek
- Department of Human Genetics, University Medical Center, Leiden, Netherlands
| | - Nemani V. Prasadarao
- Division of Infectious Diseases, The Saban Research Institute, Childrens Hospital Los Angeles, Los Angeles, California, United States of America
- Keck School of Medicine, University of Southern California, Los Angeles, California, United States of America
- * E-mail:
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Taillé C, Grootenboer-Mignot S, Boursier C, Michel L, Debray MP, Fagart J, Barrientos L, Mailleux A, Cigna N, Tubach F, Marchal-Sommé J, Soler P, Chollet-Martin S, Crestani B. Identification of periplakin as a new target for autoreactivity in idiopathic pulmonary fibrosis. Am J Respir Crit Care Med 2010; 183:759-66. [PMID: 20935114 DOI: 10.1164/rccm.201001-0076oc] [Citation(s) in RCA: 77] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
RATIONALE Injury to alveolar epithelial cells is central to the pathophysiology of idiopathic pulmonary fibrosis (IPF). An abnormal autoimmune response directed against antigens of the alveolar epithelium may contribute to the disease. OBJECTIVES To detect circulating autoantibodies (autoAbs) directed against epithelial structures. METHODS We performed immunoblot by separating human placental amnion extract or alveolar epithelial cell (A549 cell line) proteins on polyacrylamide gels, blotting on nitrocellulose membranes, and incubating with serum from patients with IPF (n = 40) or healthy subjects (n = 40). Proteomic analysis and mass spectrometry characterized the target protein. Inhibition experiments performed with the correspondent recombinant protein confirmed our results. MEASUREMENTS AND MAIN RESULTS We identified IgG autoAbs recognizing a 200-kD protein in the serum of patients with IPF. Proteomic analysis identified this protein as human periplakin (PPL), a component of desmosomes. Anti-PPL Abs were found by immunoblot in both serum and bronchoalveolar lavage in patients with IPF: 16/40 (40%) of them were positive versus none of the control subjects. Immunohistochemistry revealed that PPL was strongly expressed in bronchial and alveolar epithelium, but that PPL exhibited changes in intracellular localization among normal and fibrotic alveolar epithelium. In an alveolar epithelial wound repair assay, an anti-PPL IgG decreased cell migration. Recombinant PPL induced bronchoalveolar lavage T lymphocyte proliferation. Patients with IPF with anti-PPL Abs had a more severe respiratory disease, despite no difference in survival. CONCLUSIONS We found a new circulating autoAb directed against PPL in patients with IPF, associated with a more severe disease.
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Affiliation(s)
- Camille Taillé
- Service de Pneumologie, et Centre de Compétence des Maladies Pulmonaires Rares, Hôpitaux de Paris, Paris, France
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24
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Zhang CY, Booth JW. Divergent intracellular sorting of Fc{gamma}RIIA and Fc{gamma}RIIB2. J Biol Chem 2010; 285:34250-8. [PMID: 20736173 DOI: 10.1074/jbc.m110.143834] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022] Open
Abstract
The human low affinity FcγRII family includes both the activating receptor FcγRIIA and the inhibitory receptor FcγRIIB2. These receptors have opposing signaling functions but are both capable of internalizing IgG-containing immune complexes through clathrin-mediated endocytosis. We demonstrate that upon engagement by multivalent aggregated human IgG, FcγRIIA expressed in ts20 Chinese hamster fibroblasts is delivered along with its ligand to lysosomal compartments for degradation, while FcγRIIB2 dissociates from the ligand and is routed separately into the recycling pathway. FcγRIIA sorting to lysosomes requires receptor multimerization, but does not require either Src family kinase activity or ubiquitylation of receptor lysine residues. The sorting of FcγRIIB2 away from a degradative fate is not due to its lower affinity for IgG and occurs even upon persistent receptor aggregation. Upon co-engagement of FcγRIIA and FcγRIIB2, the receptors are sorted independently to distinct final fates after dissociation of co-clustering ligand. These results reveal fundamental differences in the trafficking behavior of different Fcγ receptors.
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Affiliation(s)
- Christine Y Zhang
- Department of Immunology, University of Toronto, Toronto, Ontario M5S 1A8, Canada
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25
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Bakema JE, Hiemstra IH, Bakker J, de Haij S, Kok Y, Adema G, van Egmond M, Coffer PJ, van de Winkel JGJ, Leusen JHW. c-Jun activating binding protein 1 binds to the IgA receptor and modulates protein levels of FcαRI and FcRγ-chain. Eur J Immunol 2010; 40:2035-40. [DOI: 10.1002/eji.200939985] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
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Abstract
The complexity and number of antigens (Ags) seen during an immune response has hampered the development of malaria vaccines. Antibodies (Abs) play an important role in immunity to malaria and their passive administration is effective at controlling the disease. Abs represent approximately 25% of all proteins undergoing clinical trials, and these 'smart biologicals' have undergone a major revival with the realization that Abs lie at the interface between innate and adaptive immunity. At least 18 Abs have FDA approval for clinical use and approximately 150 are in clinical trials, the majority for the treatment of cancer, allograft rejection or autoimmune disease. Despite these triumphs none are in development for malaria, principally because they are perceived as being too expensive for a disease mainly afflicting poor and marginalized populations. Although unlikely, at least in the foreseeable future, that Ab-based prophylaxis will be made available to the millions of people at risk from malaria, they may be incorporated into current vaccine approaches, since Abs act as correlates of protection in studies aimed at defining the best Ags to include in vaccines. Abs may also form the basis for novel vaccination strategies by targeting Ags to appropriate antigen presenting cells. Therefore, to develop the most efficacious vaccines it will be necessary to fully understand which Abs and Fc-receptors (FcRs) are best engaged for a positive outcome.
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Affiliation(s)
- R J Pleass
- Institute of Genetics, Queen's Medical Centre, Nottingham NG7 2UH, UK.
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27
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Pleass RJ, Behnke JM. B-cells get the T-cells but antibodies get the worms. Trends Parasitol 2009; 25:443-6. [PMID: 19734092 PMCID: PMC3115547 DOI: 10.1016/j.pt.2009.07.001] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2009] [Revised: 06/23/2009] [Accepted: 07/08/2009] [Indexed: 01/06/2023]
Abstract
Two recent papers published in Immunity and Cell Host & Microbe underline the great importance of B cells and of antibodies (Abs) in orchestrating crucial T helper cell type 2 (Th2) protective immune responses to gastrointestinal nematodes. The findings in animal models now raise major questions as to how B cells and Abs carry out these functions in humans. Here we discuss recent technological advances in humanizing animal models at the level of both Abs and their Fc-receptors, that might provide some answers.
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Affiliation(s)
- Richard J Pleass
- Institute of Genetics, and Parasite Biology and Immunogenetics Research Group, Queen's Medical Centre, University of Nottingham, NG7 2UH, UK.
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28
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Dale BM, Traum D, Erdjument-Bromage H, Tempst P, Greenberg S. Phagocytosis in macrophages lacking Cbl reveals an unsuspected role for Fc gamma receptor signaling and actin assembly in target binding. THE JOURNAL OF IMMUNOLOGY 2009; 182:5654-62. [PMID: 19380812 DOI: 10.4049/jimmunol.0803942] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Fc gamma receptor (Fc gammaR)-mediated phagocytosis is known to require tyrosine kinases (TKs). We identified c-Cbl and Cbl-b as proteins that undergo tyrosine phosphorylation during phagocytosis. Cbl-deficient macrophages displayed enhanced Fc gammaR-mediated signaling and phagocytosis. Surprisingly, binding of IgG-coated targets (EIgG) was also enhanced. c-Cbl-deficient macrophages expressed less Fc gammaRIIb, the inhibitory Fc gamma receptor; however, this did not account for enhanced target binding. We isolated the function of one Fc receptor isoform, Fc gammaRI, using IgG2a-coated targets (EIgG2a). Cbl-deficient macrophages demonstrated a disproportionate increase in binding EIgG2a, suggesting that signal strength regulates binding efficiency toward opsonized targets. In resting cells, Fc gammaRI colocalized with the Src family TK Hck in F-actin-rich structures, which was enhanced in Cbl-deficient macrophages. Target binding was sensitive to TK inhibitors, profoundly inhibited following depletion of cholesterol, and ablated at 4 degrees C or in the presence of inhibitors of actin polymerization. Sensitivity of EIgG binding to cytoskeletal disruption was inversely proportional to opsonin density. These findings challenge the view that Fc gammaR-mediated binding is a passive event. They suggest that dynamic engagement of TKs and the cytoskeleton enables macrophages to serve as cellular "Venus fly traps", with the capacity to capture phagocytic targets under conditions of limiting opsonin density.
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Affiliation(s)
- Benjamin M Dale
- Department of Pharmacology, Columbia University College of Physicians & Surgeons, New York, NY 10032, USA
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29
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Abstract
The aggregation of cell surface Fc receptors by immune complexes induces a number of important antibody-dependent effector functions. It is becoming increasingly evident that the organization of key immune proteins has a significant impact on the function of these proteins. Comparatively little is known, however, about the nature of Fc receptor spatiotemporal organization. This review outlines the current literature concerning human Fc receptor spatial organization and physiological function.
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30
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Jansen BJH, Eleveld-Trancikova D, Sanecka A, van Hout-Kuijer M, Hendriks IAM, Looman MGW, Leusen JHW, Adema GJ. OS9 interacts with DC-STAMP and modulates its intracellular localization in response to TLR ligation. Mol Immunol 2008; 46:505-15. [PMID: 18952287 DOI: 10.1016/j.molimm.2008.06.032] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2008] [Revised: 06/23/2008] [Accepted: 06/25/2008] [Indexed: 10/21/2022]
Abstract
Dendritic cell-specific transmembrane protein (DC-STAMP) has been first identified as an EST in a cDNA library of human monocyte-derived dendritic cells (DC). DC-STAMP is a multimembrane spanning protein that has been implicated in skewing haematopoietic differentiation of bone marrow cells towards the myeloid lineage, and in cell fusion during osteoclastogenesis and giant cell formation. To gain molecular insight in how DC-STAMP exerts its function, DC-STAMP interacting proteins were identified in a yeast-2-hybrid analysis. Herein, we report that amplified in osteosarcoma 9 (OS9) physically interacts with DC-STAMP, and that both proteins colocalize in the endoplasmic reticulum in various cell lines, including immature DC. OS9 has previously been implicated in ER-to-Golgi transport and transcription factor turnover. Interestingly, we now demonstrate that toll-like receptor (TLR)-induced maturation of DC leads to the translocation of DC-STAMP from the ER to the Golgi while OS9 localization is unaffected. Applying TLR-expressing CHO cells we could confirm ER-to-Golgi translocation of DC-STAMP following TLR stimulation and demonstrated that the DC-STAMP/OS9 interaction is involved in this process. Collectively, the data indicate that OS9 is critically involved in the modulation of ER-to-Golgi transport of DC-STAMP in response to TLR triggering, suggesting a novel role for OS9 in myeloid differentiation and cell fusion.
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Affiliation(s)
- Bastiaan J H Jansen
- Department of Tumor Immunology, Nijmegen Centre for Molecular Life Sciences, Radboud University Nijmegen Medical Centre, PO Box 9101, 6500 HB Nijmegen, The Netherlands
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31
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Bakema JE, Bakker A, de Haij S, Honing H, Bracke M, Koenderman L, Vidarsson G, van de Winkel JGJ, Leusen JHW. Inside-Out Regulation of FcαRI (CD89) Depends on PP2A. THE JOURNAL OF IMMUNOLOGY 2008; 181:4080-8. [DOI: 10.4049/jimmunol.181.6.4080] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
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32
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Beekman JM, van der Poel CE, van der Linden JA, van den Berg DLC, van den Berghe PVE, van de Winkel JGJ, Leusen JHW. Filamin A Stabilizes FcγRI Surface Expression and Prevents Its Lysosomal Routing. THE JOURNAL OF IMMUNOLOGY 2008; 180:3938-45. [DOI: 10.4049/jimmunol.180.6.3938] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
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Beekman JM, van der Linden JA, van de Winkel JGJ, Leusen JHW. FcgammaRI (CD64) resides constitutively in lipid rafts. Immunol Lett 2008; 116:149-55. [PMID: 18207250 DOI: 10.1016/j.imlet.2007.12.003] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2007] [Revised: 12/05/2007] [Accepted: 12/06/2007] [Indexed: 01/24/2023]
Abstract
Cellular membranes contain microdomains known as 'lipid rafts' or detergent-insoluble microdomains (DRM), enriched in cholesterol and sphingolipids. DRM can play an important role in many cellular processes, including signal transduction, cytoskeletal organization, and pathogen entry. Many receptors like T cell receptors, B cell receptors and IgE receptors have been shown to reside in DRM. The majority of these receptors depend on multivalent ligand interaction to associate with these microdomains. We, here, study association between the high affinity IgG receptor, FcgammaRI (CD64), and membrane microdomains. FcgammaRI is a 72kDa type I glycoprotein that can mediate phagocytosis of opsonized pathogens, but can also effectively capture small immune complexes, and facilitates antigen presentation. We found FcgammaRI to predominantly reside within detergent-insoluble buoyant membranes, together with FcRgamma-chain, but independent of cross-linking ligand. With the use of confocal imaging, FcgammaRI was found to co-patch with GM1, a microdomain-enriched glycolipid. Depletion of cellular cholesterol, furthermore, modulated FcgammaRI-ligand interactions. These data indicated FcgammaRI to reside within lipid rafts without prior triggering of the receptor.
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Affiliation(s)
- Jeffrey M Beekman
- Immunotherapy Laboratory, Department of Immunology, University Medical Center Utrecht, Utrecht, The Netherlands
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Otten MA, Leusen JHW, Rudolph E, van der Linden JA, Beelen RHJ, van de Winkel JGJ, van Egmond M. FcR γ-Chain Dependent Signaling in Immature Neutrophils Is Mediated by FcαRI, but Not by FcγRI. THE JOURNAL OF IMMUNOLOGY 2007; 179:2918-24. [PMID: 17709506 DOI: 10.4049/jimmunol.179.5.2918] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Neutrophil-mediated tumor cell lysis is more efficiently triggered by FcalphaRI (CD89), than by FcgammaRI (CD64). This difference is most evident in immature neutrophils in which FcgammaRI-mediated tumor cell lysis is absent. In this study, we show that FcR gamma-chain-dependent functions (such as Ab-dependent cellular cytotoxicity and respiratory burst), as well as signaling (calcium mobilization and MAPK phosphorylation), were potently triggered via FcalphaRI, but not via FcgammaRI, in immature neutrophils. Internalization, an FcR gamma-chain-independent function, was, however, effectively initiated via both receptors. These data suggest an impaired functional association between FcgammaRI and the FcR gamma-chain, which prompted us to perform coimmunoprecipitation experiments. As a weaker association was observed between FcgammaRI and FcR gamma-chain, compared with FcalphaRI and FcR gamma-chain, our data support that differences between FcalphaRI- and FcgammaRI-mediated functions are attributable to dissimilarities in association with the FcR gamma-chain.
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Affiliation(s)
- Marielle A Otten
- Immunotherapy Laboratory, Department of Immunology, University Medical Center, Utrecht, The Netherlands
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35
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Boczonadi V, McInroy L, Määttä A. Cytolinker cross-talk: periplakin N-terminus interacts with plectin to regulate keratin organisation and epithelial migration. Exp Cell Res 2007; 313:3579-91. [PMID: 17662978 DOI: 10.1016/j.yexcr.2007.07.005] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2007] [Revised: 07/06/2007] [Accepted: 07/07/2007] [Indexed: 02/02/2023]
Abstract
Periplakin is a cytoskeletal linker protein that participates in the assembly of epidermal cell cornified envelope and regulates keratin organisation in simple epithelial cells. We have generated a stably transfected MCF-7 subclone expressing HA-tagged periplakin N-terminus to identify molecular interactions of periplakin. Co-immunoprecipitation with anti-HA antibodies and mass spectrometry identified a 500-kDa periplakin-interacting protein as plectin, another plakin family member. Plectin-periplakin interaction was confirmed by immunoblotting of complexes immunoprecipitated by either anti-HA or anti-plectin antibodies. Transient transfections of periplakin deletion constructs indicated that first 133 amino acid residues of the N-terminus are sufficient for co-localisation with plectin at MCF-7 cell borders. Immunofluorescence analysis demonstrated that periplakin and plectin isoforms 1, 1f and 1k co-localise at cell borders of MCF-7 epithelia and that plectin-1f and 1k co-localise with periplakin in suprabasal epidermis. Ablation of plectin by siRNA in HaCaT keratinocytes resulted in aggregation of periplakin to small clusters. Scratch-wounded MCF-7 epithelia expressing periplakin N-terminus showed accelerated keratin re-organisation that was inhibited by siRNA knock-down of plectin. Finally, ablation of either periplakin or plectin, or both proteins simultaneously, impaired migration of MCF-7 epithelial sheets. Thus, we have identified a novel functional co-localisation between two plakin cytolinker proteins.
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Affiliation(s)
- Veronika Boczonadi
- Centre for Stem Cell Research and Regenerative Medicine, School of Biological and Biomedical Sciences, University of Durham, DH1 3LE, Durham, UK
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36
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McIntosh RS, Shi J, Jennings RM, Chappel JC, de Koning-Ward TF, Smith T, Green J, van Egmond M, Leusen JHW, Lazarou M, van de Winkel J, Jones TS, Crabb BS, Holder AA, Pleass RJ. The importance of human FcgammaRI in mediating protection to malaria. PLoS Pathog 2007; 3:e72. [PMID: 17511516 PMCID: PMC1868954 DOI: 10.1371/journal.ppat.0030072] [Citation(s) in RCA: 90] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2007] [Accepted: 04/04/2007] [Indexed: 11/20/2022] Open
Abstract
The success of passive immunization suggests that antibody-based therapies will be effective at controlling malaria. We describe the development of fully human antibodies specific for Plasmodium falciparum by antibody repertoire cloning from phage display libraries generated from immune Gambian adults. Although these novel reagents bind with strong affinity to malaria parasites, it remains unclear if in vitro assays are predictive of functional immunity in humans, due to the lack of suitable animal models permissive for P. falciparum. A potentially useful solution described herein allows the antimalarial efficacy of human antibodies to be determined using rodent malaria parasites transgenic for P. falciparum antigens in mice also transgenic for human Fc-receptors. These human IgG1s cured animals of an otherwise lethal malaria infection, and protection was crucially dependent on human FcγRI. This important finding documents the capacity of FcγRI to mediate potent antimalaria immunity and supports the development of FcγRI-directed therapy for human malaria. Malaria rivals HIV and tuberculosis as the world's most deadly infection killing a child every 30 seconds. Antibodies and their receptors (Fc-receptors) have been shown to be vital for the development of protective immunity, and as such they act as correlates of protection in studies aimed at defining the best antigens to incorporate into current vaccines. Understanding antibody types and Fc-receptors that optimally induce immunity is therefore vital to developing the best vaccines. Surrogate markers of antibody efficacy currently rely on in vitro assays that are laborious and difficult to reproduce. It remains unclear if such in vitro assays are predictive of functional immunity in humans due to the lack of suitable animal models permissive for Plasmodium falciparum. Here, we create a transgenic in vivo mouse model that has significant advantage over the use of new world primates, the only other model for human malaria. We demonstrate that this model defines an Fc-dependent mechanism of parasite destruction that cannot be assessed in current in vitro assays. The model provides both a test for therapeutic antibody efficacy prior to clinical trials in humans and an important tool in malaria vaccine development.
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Affiliation(s)
- Richard S McIntosh
- Institute of Genetics, Queen's Medical Centre, University of Nottingham, United Kingdom
| | - Jianguo Shi
- Institute of Genetics, Queen's Medical Centre, University of Nottingham, United Kingdom
| | - Richard M Jennings
- Division of Parasitology, National Institute for Medical Research, Medical Research Council, London, United Kingdom
| | - Jonathan C Chappel
- Division of Parasitology, National Institute for Medical Research, Medical Research Council, London, United Kingdom
- Medical Research Council Technology, London, United Kingdom
| | | | - Tim Smith
- Institute of Genetics, Queen's Medical Centre, University of Nottingham, United Kingdom
| | - Judith Green
- Division of Parasitology, National Institute for Medical Research, Medical Research Council, London, United Kingdom
| | - Marjolein van Egmond
- Department of Molecular Cell Biology and Immunology, VU Medical Centre, Amsterdam, Netherlands
| | - Jeanette H. W Leusen
- Immunotherapy Laboratory, Department of Immunology, University Medical Centre Utrecht, Utrecht, Netherlands
| | - Maria Lazarou
- Institute of Genetics, Queen's Medical Centre, University of Nottingham, United Kingdom
| | - Jan van de Winkel
- Immunotherapy Laboratory, Department of Immunology, University Medical Centre Utrecht, Utrecht, Netherlands
- Genmab, Utrecht, Netherlands
| | - Tarran S Jones
- Medical Research Council Technology, London, United Kingdom
| | - Brendan S Crabb
- Walter and Eliza Hall Institute of Medical Research, Parkville, Victoria, Australia
| | - Anthony A Holder
- Division of Parasitology, National Institute for Medical Research, Medical Research Council, London, United Kingdom
- * To whom correspondence should be addressed. E-mail: (AAH); (RJP)
| | - Richard J Pleass
- Institute of Genetics, Queen's Medical Centre, University of Nottingham, United Kingdom
- * To whom correspondence should be addressed. E-mail: (AAH); (RJP)
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37
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Long HA, Boczonadi V, McInroy L, Goldberg M, Määttä A. Periplakin-dependent re-organisation of keratin cytoskeleton and loss of collective migration in keratin-8-downregulated epithelial sheets. J Cell Sci 2006; 119:5147-59. [PMID: 17158917 DOI: 10.1242/jcs.03304] [Citation(s) in RCA: 63] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
Collective migration of epithelial sheets requires maintenance of cell-cell junctions and co-ordination of the movement of the migrating front. We have investigated the role of keratin intermediate filaments and periplakin, a cytoskeletal linker protein, in the migration of simple epithelial cells. Scratch wounding induces bundling of keratins into a cable of tightly packed filaments adjacent to the free wound edge. Keratin re-organisation is preceded by a re-distribution of periplakin away from the free wound edge. Periplakin participates with dynamic changes in the keratin cytoskeleton via its C-terminal linker domain that co-localises with okadaic-acid-treated keratin granules. Stable expression of the periplakin C-terminal domain increases keratin bundling and Ser431 keratin phosphorylation at wound edge resulting in a delay in wound closure. Ablation of periplakin by siRNA inhibits keratin cable formation and impairs wound closure. Knockdown of keratin 8 with siRNA results in (1) a loss of desmoplakin localisation at cell borders, (2) a failure of MCF-7 epithelial sheets to migrate as a collective unit and (3) accelerated wound closure in vimentin-positive HeLa and Panc-1 cell lines. Thus, keratin 8 is required for the maintenance of epithelial integrity during migration and periplakin participates in the re-organisation of keratins in migrating cells.
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Affiliation(s)
- Heather A Long
- Centre for Stem Cell Research and Regenerative Medicine, School of Biological and Biomedical Sciences, University of Durham, Durham, DH1 3LE, UK
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38
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Abstract
Abs (antibodies) are complex glycoproteins that play a crucial role in protective immunity to malaria, but their effectiveness in mediating resistance can be enhanced by genetically engineered modifications that improve on nature. These Abs also aid investigation of immune mechanisms operating to control the disease and are valuable tools in developing neutralization assays for vaccine design. This review explores how this might be achieved.
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Affiliation(s)
- Jianguo Shi
- Institute of Genetics, School of Biology, University of Nottingham NG7 2RD, UK
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39
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Otten MA, Rudolph E, Dechant M, Tuk CW, Reijmers RM, Beelen RHJ, van de Winkel JGJ, van Egmond M. Immature Neutrophils Mediate Tumor Cell Killing via IgA but Not IgG Fc Receptors. THE JOURNAL OF IMMUNOLOGY 2005; 174:5472-80. [PMID: 15843545 DOI: 10.4049/jimmunol.174.9.5472] [Citation(s) in RCA: 115] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Antitumor Abs are promising therapeutics for cancer. Currently, most Ab-based therapies focus on IgG Ab, which interact with IgG FcR (FcgammaR) on effector cells. In this study, we examined human and mouse neutrophil-mediated tumor cell lysis via targeting the IgA FcR, FcalphaRI (CD89), in more detail. FcalphaRI was the most effective FcR in triggering tumor cell killing, and initiated enhanced migration of neutrophils into tumor colonies. Importantly, immature neutrophils that are mobilized from the bone marrow upon G-CSF treatment efficiently triggered tumor cell lysis via FcalphaRI, but proved incapable of initiating tumor cell killing via FcgammaR. This may provide a rationale for the disappointing results observed in some earlier clinical trials in which patients were treated with G-CSF and antitumor Ab-targeting FcgammaR.
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MESH Headings
- Animals
- Antibody-Dependent Cell Cytotoxicity/genetics
- Antibody-Dependent Cell Cytotoxicity/immunology
- Antigens, CD/biosynthesis
- Antigens, CD/blood
- Antigens, CD/genetics
- Antigens, CD/physiology
- Bone Marrow Cells/cytology
- Bone Marrow Cells/immunology
- Bone Marrow Cells/metabolism
- Cell Communication/genetics
- Cell Communication/immunology
- Cell Death/genetics
- Cell Death/immunology
- Cell Differentiation/immunology
- Cell Line, Tumor
- Cytotoxicity Tests, Immunologic/methods
- Granulocyte Colony-Stimulating Factor/pharmacology
- Humans
- Mice
- Mice, Transgenic
- Neutrophil Infiltration/immunology
- Neutrophils/cytology
- Neutrophils/immunology
- Neutrophils/metabolism
- Receptors, Fc/biosynthesis
- Receptors, Fc/blood
- Receptors, Fc/genetics
- Receptors, Fc/physiology
- Receptors, IgG/biosynthesis
- Receptors, IgG/blood
- Receptors, IgG/genetics
- Receptors, IgG/physiology
- Signal Transduction/genetics
- Signal Transduction/immunology
- Video Recording
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Affiliation(s)
- Marielle A Otten
- Immunotherapy Laboratory, Department of Immunology, University Medical Center Utrecht, The Netherlands
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40
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Breij ECW, Heijnen P, Vloet R, Saito T, van de Winkel JGJ, Dijkstra CD, Amor S, Verbeek S. The FcRγ Chain Is Not Essential for Induction of Experimental Allergic Encephalomyelitis (EAE) or Anti-Myelin Antibody-Mediated Exacerbation of EAE. J Neuropathol Exp Neurol 2005; 64:304-11. [PMID: 15835266 DOI: 10.1093/jnen/64.4.304] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
Macrophages are considered essential mediators in multiple sclerosis (MS) pathogenesis, presumably through myelin phagocytosis and release of inflammatory mediators. Macrophages and microglia express activating Fcgamma receptors (FcgammaRI and FcgammaRIII), which depend on the FcRgamma chain for surface expression and signaling. In MS lesions, crosslinking of FcgammaR by immunoglobulins (IgG) directed against myelin may enhance myelin phagocytosis and inflammation. We studied the role of FcgammaR and anti-myelin antibodies in MOG35-55-induced experimental allergic encephalomyelitis (EAE) in C57BL/6 mice, a model of MS-like disease. Incidence and severity of EAE were similar in FcRy chain-/- (FcRgamma-/-) and wild-type (wt) mice, albeit with delayed onset in FcRgamma-/- mice. This demonstrates that the FcRy chain is not essential for induction of EAE, but that FcRgamma signaling may contribute to the preclinical phase. The role of FcgammaR in antibody-mediated demyelination was addressed by injection of anti-myelin antibodies (Z12 mAb) at onset of MOG35-55-induced EAE. Injection of Z12 mAb rapidly reduced survival time in both wt and FcRgamma-/- mice, demonstrating that antibody-mediated exacerbation of EAE is independent of the FcRgamma chain. Interestingly, Z12-induced exacerbation of inflammation and demyelination persisted longer in wt than FcRgamma-/- mice, suggesting that IgG-FcgammaR interactions may contribute to a sustained pathologic effect of anti-myelin antibodies in the CNS.
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Affiliation(s)
- Esther C W Breij
- Department of Molecular Cell Biology and Immunology, VU Medical Center, Amsterdam, The Netherlands.
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41
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Kalinin AE, Kalinin AE, Aho M, Uitto J, Aho S. Breaking the Connection: Caspase 6 Disconnects Intermediate Filament-Binding Domain of Periplakin from its Actin-Binding N-Terminal Region. J Invest Dermatol 2005; 124:46-55. [PMID: 15654952 DOI: 10.1111/j.0022-202x.2004.23507.x] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Periplakin is a member of the plakin family of cytolinkers that connect cytoskeletal networks to each other as well as to the cell junctional complexes. Here, we demonstrate a direct molecular interaction between actin and periplakin. Furthermore, the oligomerization state of periplakin was shown to determine specificity of its binding to intermediate filaments (IF) in vitro. Both the filament association and the cell membrane localization of periplakin were confirmed in the cells overexpressing human periplakin. Double labeling of the N- and C-terminally tagged periplakin revealed unexpected lack of co-localization of periplakin ends in a confluent culture, and separation of the periplakin ends was even more pronounced in apoptotic cells. Western analysis revealed that after induction of apoptosis, periplakin becomes cleaved close to its C-terminal tail. Only the distinct cleavage products, but not the full-length periplakin, were present in the cells detached from the solid support during the apoptotic process. We show that caspase 6 cleaves periplakin at an unconventional recognition site, amino acid sequence TVAD. Thus, the separation of periplakin ends disconnects the actin-binding head-rod domain from the IF-binding C-terminal domain. We show that specific cleavage products co-exist with the full-length periplakin in cells, suggesting physiological consequences due to their altered binding specificities.
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Affiliation(s)
- Andrey E Kalinin
- Laboratory of Skin Biology, National Institute of Arthritis and Musculoskeletal and Skin Diseases, National Institutes of Health, Bethesda, Maryland, USA
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