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Saeed MB, Record J, Westerberg LS. Two sides of the coin: Cytoskeletal regulation of immune synapses in cancer and primary immune deficiencies. INTERNATIONAL REVIEW OF CELL AND MOLECULAR BIOLOGY 2020; 356:1-97. [DOI: 10.1016/bs.ircmb.2020.06.001] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
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2
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Perdomo-Celis F, Velilla PA, Taborda NA, Rugeles MT. An altered cytotoxic program of CD8+ T-cells in HIV-infected patients despite HAART-induced viral suppression. PLoS One 2019; 14:e0210540. [PMID: 30625227 PMCID: PMC6326488 DOI: 10.1371/journal.pone.0210540] [Citation(s) in RCA: 28] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2018] [Accepted: 12/27/2018] [Indexed: 01/30/2023] Open
Abstract
Despite the suppression of viral replication induced by the highly active anti-retroviral therapy (HAART), an increased immune activation and inflammatory state persists in HIV-infected patients, contributing to lower treatment response and immune reconstitution, and development of non-AIDS conditions. The chronic activation and inflammation affect the functionality and differentiation of CD8+ T-cells, particularly reducing their cytotoxic capacity, which is critical in the control of HIV replication. Although previous studies have shown that HAART induce a partial immune reconstitution, its effect on CD8+ T-cells cytotoxic function, as well as its relationship with the inflammatory state, is yet to be defined. Here, we characterized the functional profile of polyclonal and HIV-specific CD8+ T cells, based on the expression of cell activation and differentiation markers, in individuals chronically infected with HIV, under HAART. Compared with seronegative controls, CD8+ T-cells from patients on HAART exhibited a low degranulation capacity (surface expression of CD107a), with consequent low secreted levels and high intracellular expression of granzyme B and perforin. This degranulation defect was particularly observed in those cells expressing the activation marker HLA-DR, which were further characterized as effector memory cells with high expression of CD57. The expression of CD107a, but not of granzyme B and perforin, in CD8+ T-cells from HIV-infected patients on HAART reached levels similar to those in seronegative controls when the treatment duration was higher than 25 months. In addition, the expression of CD107a was negatively correlated with the expression of exhaustion markers on CD8+ T-cells and the plasma inflammatory molecule sCD14. Thus, despite HAART-induced viral suppression, CD8+ T-cells from HIV-infected patients have an alteration in their cytotoxic program. This defect is associated with the cellular activation, differentiation and exhaustion state, as well as with the inflammation levels, and can be partially recovered with a long and continuous treatment.
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Affiliation(s)
- Federico Perdomo-Celis
- Grupo Inmunovirología, Facultad de Medicina, Universidad de Antioquia, UdeA, Medellín, Colombia
| | - Paula A. Velilla
- Grupo Inmunovirología, Facultad de Medicina, Universidad de Antioquia, UdeA, Medellín, Colombia
| | - Natalia A. Taborda
- Grupo Inmunovirología, Facultad de Medicina, Universidad de Antioquia, UdeA, Medellín, Colombia
- Grupo de Investigaciones Biomédicas Uniremington, Programa de Medicina, Facultad de Ciencias de la Salud, Corporación Universitaria Remington, Medellín, Colombia
| | - María Teresa Rugeles
- Grupo Inmunovirología, Facultad de Medicina, Universidad de Antioquia, UdeA, Medellín, Colombia
- * E-mail:
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3
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Hart M, Kern F, Backes C, Rheinheimer S, Fehlmann T, Keller A, Meese E. The deterministic role of 5-mers in microRNA-gene targeting. RNA Biol 2018; 15:819-825. [PMID: 29749304 DOI: 10.1080/15476286.2018.1462652] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/16/2022] Open
Abstract
MiRNAs play a central role in physiological and pathological processes. Both for the biological understanding and for their clinical application, it is essential to understand the interaction of miRNAs and their targets. Target identification largely hinges on in-silico prediction, which requires a complete consideration of miRNA binding sites within the UTRs of target genes. Here, we show that 5-mer sites might also play an essential role for human miRNA-target binding. We implemented and employed an algorithm to all pairs of 2,588 human miRNAs annotated in miRBase and the 3' UTRs of 16725 genes (>43 million combinations). Our in-silico analysis showed a highly significant enrichment (p = 1.4 × 10-69) of 5-mer binding sites in 3' UTRs across all experimentally validated miRNA-target gene pairs. We next confirmed the central role of 5-mer binding sites by reporter assays and demonstrated that two non-canonical 5-mer sites of miR-34a in the 3' UTR of T-cell receptor alpha (TCRA) have a significantly stronger influence on its posttranscriptional regulation than the canonical binding sites. These observations indicate an essential role of 5-mer binding sites for the miRNA targeting in human cells.
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Affiliation(s)
- Martin Hart
- a Institute of Human Genetics, Saarland University , Homburg , Germany
| | - Fabian Kern
- b Chair for Clinical Bioinformatics, Saarland University , Saarbrücken , Germany
| | - Christina Backes
- b Chair for Clinical Bioinformatics, Saarland University , Saarbrücken , Germany
| | | | - Tobias Fehlmann
- b Chair for Clinical Bioinformatics, Saarland University , Saarbrücken , Germany
| | - Andreas Keller
- b Chair for Clinical Bioinformatics, Saarland University , Saarbrücken , Germany
| | - Eckart Meese
- a Institute of Human Genetics, Saarland University , Homburg , Germany
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4
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Hart M, Rheinheimer S, Leidinger P, Backes C, Menegatti J, Fehlmann T, Grässer F, Keller A, Meese E. Identification of miR-34a-target interactions by a combined network based and experimental approach. Oncotarget 2018; 7:34288-99. [PMID: 27144431 PMCID: PMC5085156 DOI: 10.18632/oncotarget.9103] [Citation(s) in RCA: 25] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2016] [Accepted: 04/16/2016] [Indexed: 12/25/2022] Open
Abstract
Circulating miRNAs have been associated with numerous human diseases. The lack of understanding the functional roles of blood-born miRNAs limits, however, largely their value as disease marker. In a systems biology analysis we identified miR-34a as strongly associated with pathogenesis. Genome-wide analysis of miRNAs in blood cell fractions highlighted miR-34a as most significantly up-regulated in CD3+ cells of lung cancer patients. By our in silico analysis members of the protein kinase C family (PKC) were indicated as miR-34a target genes. Using a luciferase assay, we confirmed binding of miR-34a-5p to target sequences within the 3′UTRs of five PKC family members. To verify the biological effect, we transfected HEK 293T and Jurkat cells with miR-34a-5p causing reduced endogenous protein levels of PKC isozymes. By combining bioinformatics approaches with experimental validation, we demonstrate that one of the most relevant disease associated miRNAs has the ability to control the expression of a gene family.
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Affiliation(s)
- Martin Hart
- Institute of Human Genetics, Saarland University, 66421 Homburg, Germany
| | | | - Petra Leidinger
- Institute of Human Genetics, Saarland University, 66421 Homburg, Germany
| | - Christina Backes
- Chair for Clinical Bioinformatics, Saarland University, 66123 Saarbrücken, Germany
| | - Jennifer Menegatti
- Institute of Virology, Saarland University Medical School, 66421 Homburg, Germany
| | - Tobias Fehlmann
- Chair for Clinical Bioinformatics, Saarland University, 66123 Saarbrücken, Germany
| | - Friedrich Grässer
- Institute of Virology, Saarland University Medical School, 66421 Homburg, Germany
| | - Andreas Keller
- Chair for Clinical Bioinformatics, Saarland University, 66123 Saarbrücken, Germany
| | - Eckart Meese
- Institute of Human Genetics, Saarland University, 66421 Homburg, Germany
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5
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Zhao Z, deMayo JA, West AM, Balunas MJ, Zweifach A. Development of an Enhanced Phenotypic Screen of Cytotoxic T-Lymphocyte Lytic Granule Exocytosis Suitable for Use with Synthetic Compound and Natural Product Collections. JOURNAL OF BIOMOLECULAR SCREENING 2016; 21:556-66. [PMID: 27048485 DOI: 10.1177/1087057116643260] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/07/2015] [Accepted: 03/15/2016] [Indexed: 01/11/2023]
Abstract
We previously developed an assay of cytotoxic T-lymphocyte lytic granule exocytosis based on externalization of LAMP-1/CD107A using nonphysiological stimuli to generate maximal levels of exocytosis. Here, we used polystyrene beads coated with anti-CD3 antibodies to stimulate cells. Light scatter let us distinguish cells that contacted beads from cells that had not, allowing comparison of signaling events and exocytosis from stimulated and unstimulated cells in one sample. Bead stimulation resulted in submaximal exocytosis, making it possible to detect compounds that either augment or inhibit lytic granule exocytosis. Coupled with the assay's ability to distinguish responses in cells that have and have not contacted a stimulatory bead, it is possible to detect three kinds of compounds: inhibitors, stimulators, which cause exocytosis, and augmenters, which enhance receptor-stimulated exocytosis. To validate the assay, we screened a set of synthetic compounds identified using our previous assay and a library of 320 extracts prepared from tunicate-associated bacteria. One of the extracts augmented exocytosis threefold. Activity-guided fractionation and structure elucidation revealed that this compound is the known PKC activator teleocidin A-1. We conclude that our modified assay is suitable for screening synthetic compound plates and natural product collections, and will be useful for identifying immunologically active small molecules.
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Affiliation(s)
- Ziyan Zhao
- Department of Molecular and Cell Biology, University of Connecticut at Storrs, Storrs, CT, USA
| | - James A deMayo
- Division of Medicinal Chemistry, Department of Pharmaceutical Sciences, University of Connecticut, Storrs, CT, USA
| | - Ashley M West
- Division of Medicinal Chemistry, Department of Pharmaceutical Sciences, University of Connecticut, Storrs, CT, USA
| | - Marcy J Balunas
- Division of Medicinal Chemistry, Department of Pharmaceutical Sciences, University of Connecticut, Storrs, CT, USA
| | - Adam Zweifach
- Department of Molecular and Cell Biology, University of Connecticut at Storrs, Storrs, CT, USA
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Affiliation(s)
- Amnon Altman
- Division of Cell Biology, La Jolla Institute for Allergy and Immunology, La Jolla, California 92037; ,
| | - Kok-Fai Kong
- Division of Cell Biology, La Jolla Institute for Allergy and Immunology, La Jolla, California 92037; ,
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Davis LC, Platt FM, Galione A. Preferential Coupling of the NAADP Pathway to Exocytosis in T-Cells. MESSENGER (LOS ANGELES, CALIF. : PRINT) 2015; 4:53-66. [PMID: 27330870 PMCID: PMC4910867 DOI: 10.1166/msr.2015.1040] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
A cytotoxic T-lymphocyte (CTL) kills an infected or tumorigenic cell by Ca2+-dependent exocytosis of cytolytic granules at the immunological synapse formed between the two cells. However, these granules are more than reservoirs of secretory cytolytic proteins but may also serve as unique Ca2+ signaling hubs that autonomously generate their own signals for exocytosis. This review discusses a selective role for the Ca2+-mobilizing messenger, nicotinic acid adenine dinucleotide phosphate (NAADP) and its molecular targets, two-pore channels (TPCs), in stimulating exocytosis. Given that TPCs reside on the exocytotic granules themselves, these vesicles generate as well as respond to NAADP-dependent Ca2+ signals, which may have wider implications for stimulus-secretion coupling, vesicular fusion, and patho-physiology.
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Affiliation(s)
- Lianne C. Davis
- Department of Pharmacology, University of Oxford, Oxford, OX1 3QT, UK
| | - Frances M. Platt
- Department of Pharmacology, University of Oxford, Oxford, OX1 3QT, UK
| | - Antony Galione
- Department of Pharmacology, University of Oxford, Oxford, OX1 3QT, UK
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Comet NR, Aguiló JI, Rathoré MG, Catalán E, Garaude J, Uzé G, Naval J, Pardo J, Villalba M, Anel A. IFNα signaling through PKC-θ is essential for antitumor NK cell function. Oncoimmunology 2014; 3:e948705. [PMID: 25960930 DOI: 10.4161/21624011.2014.948705] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2014] [Accepted: 06/06/2014] [Indexed: 11/19/2022] Open
Abstract
We have previously shown that the development of a major histocompatibility complex class I (MHC-I)-deficient tumor was favored in protein kinase C-θ knockout (PKC-θ-/-) mice compared to that occurring in wild-type mice. This phenomenon was associated with scarce recruitment of natural killer (NK) cells to the tumor site, as well as impaired NK cell activation and reduced cytotoxicity ex vivo. Poly-inosinic:cytidylic acid (poly I:C) treatment activated PKC-θ in NK cells depending on the presence of a soluble factor produced by a different splenocyte subset. In the present work, we sought to analyze whether interleukin-15 (IL-15) and/or interferon-α (IFNα) mediate PKC-θ-dependent antitumor NK cell function. We found that IL-15 improves NK cell viability, granzyme B expression, degranulation capacity and interferon-γ (IFNγ) secretion independently of PKC-θ. In contrast, we found that IFNα improves the degranulation capability of NK cells against target cancer cells in a PKC-θ-dependent fashion both ex vivo and in vivo. Furthermore, IFNα induces PKC-θ auto-phosphorylation in NK cells, in a signal transduction pathway involving both phosphatidylinositol-3-kinase (PI3K) and phospholipase-C (PLC) activation. PKC-θ dependence was further implicated in IFNα-induced transcriptional upregulation of chemokine (C-X-C motif) ligand 10 (CXCL10), a signal transducer and activator of transcription-1 (STAT-1)-dependent target of IFNα. The absence of PKC-θ did not affect IFNα-induced STAT-1 Tyr701 phosphorylation but affected the increase in STAT-1 phosphorylation on Ser727, attenuating CXCL10 secretion. This connection between IFNα and PKC-θ in NK cells may be exploited in NK cell-based tumor immunotherapy.
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Key Words
- CDK8, cyclin-dependent kinase 8
- CXCL10
- CXCL10, (C-X-C motif) ligand 10/CXCL10
- FCS, fetal calf serum
- IFN-α, IL-15
- IFNA1
- IFNα, interferon-α
- IFNγ, interferon-γ, IFNG
- IL-15, interleukin-15/IL15
- MACS, magnetic cell separation
- MEF, murine embryonic fibroblast
- MHC-I, major histocompability complex class I/MHC-I
- NK cells
- NK, natural killer
- PI3K, phosphatidylinositol-3-kinase
- PKC-θ
- PKC-θ, protein kinase C-θ, PRKCQ
- PLC, phospholipase-C
- Poly I:C, poly-inosinic:cytidilic acid
- RT-PCR, real-time polymerase chain reaction
- STAT-1, signal transducer and activator of transcription-1/STAT1.
- mAb, monoclonal antibody
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Affiliation(s)
- Natalia R Comet
- Apoptosis, Immunity & Cancer Group; Department of Biochemistry and Molecular and Cell Biology ; University of Zaragoza and Aragón Health Research Institute (IIS Aragón) ; Zaragoza, Spain
| | - Juan Ignacio Aguiló
- Apoptosis, Immunity & Cancer Group; Department of Biochemistry and Molecular and Cell Biology ; University of Zaragoza and Aragón Health Research Institute (IIS Aragón) ; Zaragoza, Spain
| | - Moeez G Rathoré
- INSERM U1040; Université de Montpellier 1; UFR Médecine ; Montpellier, France
| | - Elena Catalán
- Apoptosis, Immunity & Cancer Group; Department of Biochemistry and Molecular and Cell Biology ; University of Zaragoza and Aragón Health Research Institute (IIS Aragón) ; Zaragoza, Spain
| | - Johan Garaude
- INSERM U1040; Université de Montpellier 1; UFR Médecine ; Montpellier, France
| | - Gilles Uzé
- CNRS UMR 5235; Université de Montpellier II; Place Eugene Bataillon ; Montpellier, France
| | - Javier Naval
- Apoptosis, Immunity & Cancer Group; Department of Biochemistry and Molecular and Cell Biology ; University of Zaragoza and Aragón Health Research Institute (IIS Aragón) ; Zaragoza, Spain
| | - Julián Pardo
- Immune Effector Cells Group; IIS Aragón; Biomedical Research Center of Aragón (CIBA); Nanoscience Institute of Aragon (INA); Zaragoza, Spain ; Aragón I+D Foundation (ARAID) ; Zaragoza, Spain
| | - Martín Villalba
- INSERM U1040; Université de Montpellier 1; UFR Médecine ; Montpellier, France ; Institut de Recherche en Biothérapie (IRB); CHU Montpellier ; Montpellier, France
| | - Alberto Anel
- Apoptosis, Immunity & Cancer Group; Department of Biochemistry and Molecular and Cell Biology ; University of Zaragoza and Aragón Health Research Institute (IIS Aragón) ; Zaragoza, Spain
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Uhlenbrock F, Hagemann-Jensen M, Kehlet S, Andresen L, Pastorekova S, Skov S. The NKG2D ligand ULBP2 is specifically regulated through an invariant chain-dependent endosomal pathway. THE JOURNAL OF IMMUNOLOGY 2014; 193:1654-65. [PMID: 25024379 DOI: 10.4049/jimmunol.1303275] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
Soluble ULBP2 is a marker for poor prognosis in several types of cancer. In this study we demonstrate that both soluble and cell surface-bound ULBP2 is transported via a so far unrecognized endosomal pathway. ULBP2 surface expression, but not MICA/B, could specifically be targeted and retained by affecting endosomal/lysosomal integrity and protein kinase C activity. The invariant chain was further essential for endosomal transport of ULBP2. This novel pathway was identified through screening experiments by which methylselenic acid was found to possess notable NKG2D ligand regulatory properties. The protein kinase C inhibitor methylselenic acid induced MICA/B surface expression but dominantly blocked ULBP2 surface transport. Remarkably, by targeting this novel pathway we could specifically block the production of soluble ULBP2 from different, primary melanomas. Our findings strongly suggest that the endosomal transport pathway constitutes a novel therapeutic target for ULBP2-producing tumors.
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Affiliation(s)
- Franziska Uhlenbrock
- Section for Experimental Animal Models, Laboratory of Immunology, Faculty of Health and Medical Sciences, University of Copenhagen, DK-1870 Frederiksberg, Denmark; and
| | - Michael Hagemann-Jensen
- Section for Experimental Animal Models, Laboratory of Immunology, Faculty of Health and Medical Sciences, University of Copenhagen, DK-1870 Frederiksberg, Denmark; and
| | - Stephanie Kehlet
- Section for Experimental Animal Models, Laboratory of Immunology, Faculty of Health and Medical Sciences, University of Copenhagen, DK-1870 Frederiksberg, Denmark; and
| | - Lars Andresen
- Section for Experimental Animal Models, Laboratory of Immunology, Faculty of Health and Medical Sciences, University of Copenhagen, DK-1870 Frederiksberg, Denmark; and
| | - Silvia Pastorekova
- Department of Molecular Medicine, Institute of Virology, Slovak Academy of Sciences, 845 05 Bratislava, Slovak Republic
| | - Søren Skov
- Section for Experimental Animal Models, Laboratory of Immunology, Faculty of Health and Medical Sciences, University of Copenhagen, DK-1870 Frederiksberg, Denmark; and
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10
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Davis LC, Galione A. Cytolytic granules supply Ca(2+) for their own exocytosis via NAADP and resident two-pore channels. Commun Integr Biol 2013; 6:e24175. [PMID: 23713141 PMCID: PMC3656026 DOI: 10.4161/cib.24175] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2013] [Accepted: 03/28/2013] [Indexed: 02/06/2023] Open
Abstract
When cytotoxic T-lymphocytes (CTLs) kill infected or cancerous cells they secrete cytolytic proteins (perforin and granzymes) into the target cell. These “death factors” are pre-stored in cytolytic granules within the CTL until an increase in the intracellular Ca2+ drives granule exocytosis. However, not all sources of Ca2+ stimulate exocytosis: we have recently demonstrated that it is the cytolytic granules themselves that are the source of the Ca2+ that most efficiently drives their own exocytosis; release of Ca2+ from the granules is only activated by the Ca2+-mobilizing messenger NAADP (nicotinic acid adenine dinucleotide phosphate) that acts upon target two-pore channels (TPCs) present on the granules. That NAADP is a unique stimulus of exocytosis may be of fundamental importance not only to immunology but to cell biology in general.
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Affiliation(s)
- Lianne C Davis
- Department of Pharmacology; University of Oxford; Oxford, UK
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11
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Kong KF, Altman A. In and out of the bull's eye: protein kinase Cs in the immunological synapse. Trends Immunol 2013; 34:234-42. [PMID: 23428395 DOI: 10.1016/j.it.2013.01.002] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2012] [Revised: 12/29/2012] [Accepted: 01/02/2013] [Indexed: 01/24/2023]
Abstract
The immunological synapse (IS) formed between immune cells and antigen-presenting cells (APCs) provides a platform for signaling. Protein kinase C (PKC)θ localizes in the T cell IS within the central supramolecular activation cluster (cSMAC), where it associates with CD28 and mediates T cell receptor (TCR)/CD28 signals leading to effector T (Teff) cell activation. In regulatory T (Treg) cells, PKCθ is sequestered away from the IS, and inhibits suppressive function. Other PKCs localizing in the IS mediate additional functions in various immune cells. Further work is needed to identify mechanisms underlying PKC recruitment or exclusion at the IS, potential redundancy among IS-localized PKCs, and the relevance of PKC localization for IS dynamics and lymphocyte activation.
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Affiliation(s)
- Kok-Fai Kong
- Division of Cell Biology, La Jolla Institute for Allergy and Immunology, La Jolla, CA 92037, USA
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Gharbi SI, Avila-Flores A, Soutar D, Orive A, Koretzky GA, Albar JP, Mérida I. Transient PKCα shuttling to the immunological synapse is governed by (DGK)ζ and regulates L-selectin shedding. J Cell Sci 2013; 126:2176-86. [DOI: 10.1242/jcs.118513] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023] Open
Abstract
Considerable evidence indicates that diacylglycerol (DAG) generation at the immunological synapse (IS) determines T cell functions by regulating the duration and amplitude of Ras/ERK signals. The exact mechanism by which DAG regulates Ras/ERK activation downstream of the T cell receptor (TCR) nonetheless remains poorly understood. Here we characterize PKCα as a previously unrecognized component of the machinery that translates cell receptor occupancy into Ras/ERK-propagated signals. We show transient translocation of PKCα to the IS, mediated by DAG generation at the contact area. Diacylglycerol kinase (DGK)ζ negatively regulated PKCα translocation kinetics, whereas PKCα activity limited its own persistence at the IS. Coordinated activation of DGKζ and PKCα in response to antigen recognition regulated the amplitude and duration of Ras/ERK activation; this in turn mediated early processes of T cell surface proteolysis such as L-selectin shedding. Analysis of DGKζ-deficient mice further showed that increased DAG signaling is translated to downstream elements of this pathway, as reflected by enhanced PKCα-dependent L-selectin shedding. We propose that early activation of a DAG/PKCα axis contributes to the mechanisms by which antigen affinity translates into TCR biological responses.
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13
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Davis LC, Morgan AJ, Chen JL, Snead CM, Bloor-Young D, Shenderov E, Stanton-Humphreys MN, Conway SJ, Churchill GC, Parrington J, Cerundolo V, Galione A. NAADP activates two-pore channels on T cell cytolytic granules to stimulate exocytosis and killing. Curr Biol 2012. [PMID: 23177477 PMCID: PMC3525857 DOI: 10.1016/j.cub.2012.10.035] [Citation(s) in RCA: 108] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
A cytotoxic T lymphocyte (CTL) kills an infected or tumorigenic cell by Ca2+-dependent exocytosis of cytolytic granules at the immunological synapse formed between the two cells. Although inositol 1,4,5-trisphosphate (IP3)-mediated Ca2+ release from the endoplasmic reticulum activates the store-operated Ca2+-influx pathway that is necessary for exocytosis, it is not a sufficient stimulus [1–4]. Here we identify the Ca2+-mobilizing messenger nicotinic acid adenine dinucleotide phosphate (NAADP) and its recently identified molecular target, two-pore channels (TPCs) [5–7], as being important for T cell receptor signaling in CTLs. We demonstrate that cytolytic granules are not only reservoirs of cytolytic proteins but are also the acidic Ca2+ stores mobilized by NAADP via TPC channels on the granules themselves, so that TPCs migrate to the immunological synapse upon CTL activation. Moreover, NAADP activates TPCs to drive exocytosis in a way that is not mimicked by global Ca2+ signals induced by IP3 or ionomycin, suggesting that critical, local Ca2+ nanodomains around TPCs stimulate granule exocytosis. Hence, by virtue of the NAADP/TPC pathway, cytolytic granules generate Ca2+ signals that lead to their own exocytosis and to cell killing. This study highlights a selective role for NAADP in stimulating exocytosis crucial for immune cell function and may impact on stimulus-secretion coupling in wider cellular contexts.
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Affiliation(s)
- Lianne C Davis
- Department of Pharmacology, University of Oxford, Oxford, UK.
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14
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Anel A, Aguiló JI, Catalán E, Garaude J, Rathore MG, Pardo J, Villalba M. Protein Kinase C-θ (PKC-θ) in Natural Killer Cell Function and Anti-Tumor Immunity. Front Immunol 2012; 3:187. [PMID: 22783260 PMCID: PMC3389606 DOI: 10.3389/fimmu.2012.00187] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2012] [Accepted: 06/15/2012] [Indexed: 12/24/2022] Open
Abstract
The protein kinase C-θ (PKCθ), which is essential for T cell function and survival, is also required for efficient anti-tumor immune surveillance. Natural killer (NK) cells, which express PKCθ, play a prominent role in this process, mainly by elimination of tumor cells with reduced or absent major histocompatibility complex class-I (MHC-I) expression. This justifies the increased interest of the use of activated NK cells in anti-tumor immunotherapy in the clinic. The in vivo development of MHC-I-deficient tumors is much favored in PKCθ−/− mice compared with wild-type mice. Recent data offer some clues on the mechanism that could explain the important role of PKCθ in NK cell-mediated anti-tumor immune surveillance: some studies show that PKCθ is implicated in signal transduction and anti-tumoral activity of NK cells elicited by interleukin (IL)-12 or IL-15, while others show that it is implicated in NK cell functional activation mediated by certain killer-activating receptors. Alternatively, the possibility that PKCθ is involved in NK cell degranulation is discussed, since recent data indicate that it is implicated in microtubule-organizing center polarization to the immune synapse in CD4+ T cells. The implication of PKC isoforms in degranulation has been more extensively studied in cytotoxic T lymphocyte, and these studies will be also summarized.
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Affiliation(s)
- Alberto Anel
- Departamento de Bioquímica y Biología Molecular y Celular, Universidad de Zaragoza Zaragoza, Spain
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15
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Heemskerk JW, Harper MT, Cosemans JM, Poole AW. Unravelling the different functions of protein kinase C isoforms in platelets. FEBS Lett 2011; 585:1711-6. [DOI: 10.1016/j.febslet.2011.05.017] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2011] [Revised: 04/28/2011] [Accepted: 05/04/2011] [Indexed: 11/17/2022]
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Valenzuela JO, Iclozan C, Hossain MS, Prlic M, Hopewell E, Bronk CC, Wang J, Celis E, Engelman RW, Blazar BR, Bevan MJ, Waller EK, Yu XZ, Beg AA. PKCtheta is required for alloreactivity and GVHD but not for immune responses toward leukemia and infection in mice. J Clin Invest 2009; 119:3774-86. [PMID: 19907075 DOI: 10.1172/jci39692] [Citation(s) in RCA: 63] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2009] [Accepted: 09/16/2009] [Indexed: 12/12/2022] Open
Abstract
When used as therapy for hematopoietic malignancies, allogeneic BM transplantation (BMT) relies on the graft-versus-leukemia (GVL) effect to eradicate residual tumor cells through immunologic mechanisms. However, graft-versus-host disease (GVHD), which is initiated by alloreactive donor T cells that recognize mismatched major and/or minor histocompatibility antigens and cause severe damage to hematopoietic and epithelial tissues, is a potentially lethal complication of allogeneic BMT. To enhance the therapeutic potential of BMT, we sought to find therapeutic targets that could inhibit GVHD while preserving GVL and immune responses to infectious agents. We show here that T cell responses triggered in mice by either Listeria monocytogenes or administration of antigen and adjuvant were relatively well preserved in the absence of PKC isoform theta (PKCtheta), a key regulator of TCR signaling. In contrast, PKCtheta was required for alloreactivity and GVHD induction. Furthermore, absence of PKCtheta raised the threshold for T cell activation, which selectively affected alloresponses. Most importantly, PKCtheta-deficient T cells retained the ability to respond to virus infection and to induce GVL effect after BMT. These findings suggest PKCtheta is a potentially unique therapeutic target required for GVHD induction but not for GVL or protective responses to infectious agents.
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Pores-Fernando AT, Zweifach A. Calcium influx and signaling in cytotoxic T-lymphocyte lytic granule exocytosis. Immunol Rev 2009; 231:160-73. [PMID: 19754896 DOI: 10.1111/j.1600-065x.2009.00809.x] [Citation(s) in RCA: 67] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
Cytotoxic T lymphocytes (CTLs) kill targets by releasing cytotoxic agents from lytic granules. Killing is a multi-step process. The CTL adheres to a target, allowing its T-cell receptors to recognize antigen. This triggers a signal transduction cascade that leads to the polarization of the microtubule cytoskeleton and granules towards the target, followed by exocytosis that occurs specifically at the site of contact. As with cytokine production by helper T cells (Th cells), target cell killing is absolutely dependent on Ca2+ influx, which is involved in regulating both reorientation and release. Current evidence suggests that Ca2+ influx in CTLs, as in Th cells, occurs via depletion-activated channels. The molecules that couple increases in Ca2+ to reorientation are unknown. The Ca2+/calmodulin-dependent phosphatase calcineurin, which plays a critical role in cytokine production by Th cells, is also involved in lytic granule exocytosis, although the relevant substrates remain to be identified and calcineurin activation is only one Ca2+-dependent step involved. There are thus striking similarities and important differences between Ca2+ signals in Th cells and CTLs, illustrating how cells can use similar signal transduction pathways to generate different functional outcomes.
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Affiliation(s)
- Arun T Pores-Fernando
- Department of Molecular and Cell Biology, University of Connecticut, Storrs, CT, USA
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Pores-Fernando AT, Ranaghan MYD, Zweifach A. No specific subcellular localization of protein kinase C is required for cytotoxic T cell granule exocytosis. J Biol Chem 2009; 284:25107-15. [PMID: 19592494 DOI: 10.1074/jbc.m109.011866] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Cytotoxic T cells kill virus-infected cells and tumor cells by releasing lytic granules that contain cell-killing contents. Exocytosis requires calcium influx and protein kinase C (PKC) activation. Here, we extend our previous finding regarding the lack of isoform specificity of PKCs in the granule release step, showing that mutant constitutively active PKCdelta can substitute for phorbol esters and support exocytosis. PKCdelta, a novel PKC isoform, was recently shown to play a role in lytic granule reorientation. Surprisingly, however, our results suggested that mutant PKCdelta did not localize to the plasma membrane (PM). To test directly whether PKC has to be in the PM to drive exocytosis, we generated mutants of various PKC isoforms that were tethered either to the outer mitochondrial membrane or to the PM. Tethered mutant PKCdeltas were able to promote exocytosis as effectively as the untethered version. The substrates of PKCs involved in lytic granule exocytosis are currently unknown, but subcellular localization is believed to be a critical factor in determining PKC accessibility to substrates. That there is no requirement for specific PKC localization in lytic granule exocytosis may have important implications for the identity of PKC substrates.
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Affiliation(s)
- Arun T Pores-Fernando
- Department of Molecular and Cell Biology, University of Connecticut, Storrs, Connecticut 06269-3125, USA
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19
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Aguiló JI, Garaude J, Pardo J, Villalba M, Anel A. Protein Kinase C-θ Is Required for NK Cell Activation and In Vivo Control of Tumor Progression. THE JOURNAL OF IMMUNOLOGY 2009; 182:1972-81. [DOI: 10.4049/jimmunol.0801820] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
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20
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Kassahn D, Nachbur U, Conus S, Micheau O, Schneider P, Simon HU, Brunner T. Distinct requirements for activation-induced cell surface expression of preformed Fas/CD95 ligand and cytolytic granule markers in T cells. Cell Death Differ 2009; 16:115-24. [PMID: 19079288 DOI: 10.1038/cdd.2008.133] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022] Open
Abstract
Fas (CD95/Apo-1) ligand is a potent inducer of apoptosis and one of the major killing effector mechanisms of cytotoxic T cells. Thus, Fas ligand activity has to be tightly regulated, involving various transcriptional and post-transcriptional processes. For example, preformed Fas ligand is stored in secretory lysosomes of activated T cells, and rapidly released by degranulation upon reactivation. In this study, we analyzed the minimal requirements for activation-induced degranulation of Fas ligand. T cell receptor activation can be mimicked by calcium ionophore and phorbol ester. Unexpectedly, we found that stimulation with phorbol ester alone is sufficient to trigger Fas ligand release, whereas calcium ionophore is neither sufficient nor necessary. The relevance of this process was confirmed in primary CD4(+) and CD8(+) T cells and NK cells. Although the activation of protein kinase(s) was absolutely required for Fas ligand degranulation, protein kinase C or A were not involved. Previous reports have shown that preformed Fas ligand co-localizes with other markers of cytolytic granules. We found, however, that the activation-induced degranulation of Fas ligand has distinct requirements and involves different mechanisms than those of the granule markers CD63 and CD107a/Lamp-1. We conclude that activation-induced degranulation of Fas ligand in cytotoxic lymphocytes is differently regulated than other classical cytotoxic granule proteins.
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Affiliation(s)
- D Kassahn
- Division of Immunopathology, Institute of Pathology, University of Bern, Bern, Switzerland
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21
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Beal AM, Anikeeva N, Varma R, Cameron TO, Norris PJ, Dustin ML, Sykulev Y. Protein kinase C theta regulates stability of the peripheral adhesion ring junction and contributes to the sensitivity of target cell lysis by CTL. THE JOURNAL OF IMMUNOLOGY 2008; 181:4815-24. [PMID: 18802085 DOI: 10.4049/jimmunol.181.7.4815] [Citation(s) in RCA: 58] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
Destruction of virus-infected cells by CTL is an extremely sensitive and efficient process. Our previous data suggest that LFA-1-ICAM-1 interactions in the peripheral supramolecular activation cluster (pSMAC) of the immunological synapse mediate formation of a tight adhesion junction that might contribute to the sensitivity of target cell lysis by CTL. Herein, we compared more (CD8(+)) and less (CD4(+)) effective CTL to understand the molecular events that promote efficient target cell lysis. We found that abrogation of the pSMAC formation significantly impaired the ability of CD8(+) but not CD4(+) CTL to lyse target cells despite having no effect of the amount of released granules by both CD8(+) and CD4(+) CTL. Consistent with this, CD4(+) CTL break their synapses more often than do CD8(+) CTL, which leads to the escape of the cytolytic molecules from the interface. CD4(+) CTL treatment with a protein kinase Ctheta inhibitor increases synapse stability and sensitivity of specific target cell lysis. Thus, formation of a stable pSMAC, which is partially controlled by protein kinase Ctheta, functions to confine the released lytic molecules at the synaptic interface and to enhance the effectiveness of target cell lysis.
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Affiliation(s)
- Allison M Beal
- Department of Microbiology and Immunology and Kimmel Cancer Institute, Thomas Jefferson University, Philadelphia, PA 19107, USA
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22
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Impaired anti-leukemic immune response in PKCθ-deficient mice. Mol Immunol 2008; 45:3463-9. [DOI: 10.1016/j.molimm.2008.03.016] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2008] [Accepted: 03/26/2008] [Indexed: 01/27/2023]
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23
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Pores-Fernando AT, Gaur S, Grybko MJ, Zweifach A. ERK activation is only one role of PKC in TCR-independent cytotoxic T cell granule exocytosis. Biochem Biophys Res Commun 2008; 371:630-4. [PMID: 18413231 DOI: 10.1016/j.bbrc.2008.04.028] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2008] [Accepted: 04/04/2008] [Indexed: 11/18/2022]
Abstract
Cytotoxic T cells (CTLs) kill target cells by releasing lytic agents via regulated exocytosis. Three signals are known to be required for exocytosis: an increase in intracellular Ca(2+), activation of protein kinase C (PKC) and activation of extracellular signal regulated signal kinase (ERK). ERK activation required for exocytosis depends on activity of PKC. The simplest possibility is that the sole effect of PKC required for exocytosis is ERK activation. Testing this requires dissociating ERK and PKC activation. We did this using TCR-independent stimulation of TALL-104 human leukemic CTLs. When cells are stimulated with thapsigargin and PMA, agents that increase intracellular Ca(2+) and activate PKC, respectively, PKC-dependent ERK activation is required for lytic granule exocytosis. Expressing a constitutively active mutant MAP kinase kinase activates ERK independent of PKC. However, activating ERK without PKC does not support lytic granule exocytosis, indicating that there are multiple effects of PKC required for granule exocytosis.
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Affiliation(s)
- Arun T Pores-Fernando
- Department of Molecular and Cell Biology, University of Connecticut at Storrs, 91 N Eagleville Road, Unit 3125, Storrs, CT 06268-3125, USA
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Ma JSY, Monu N, Shen DT, Mecklenbräuker I, Radoja N, Haydar TF, Leitges M, Frey AB, Vukmanovic S, Radoja S. Protein kinase Cdelta regulates antigen receptor-induced lytic granule polarization in mouse CD8+ CTL. THE JOURNAL OF IMMUNOLOGY 2007; 178:7814-21. [PMID: 17548619 PMCID: PMC3712856 DOI: 10.4049/jimmunol.178.12.7814] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Lytic granule exocytosis is the major pathway used by CD8+ CTL to kill virally infected and tumor cells. Despite the obvious importance of this pathway in adaptive T cell immunity, the molecular identity of enzymes involved in the regulation of this process is poorly characterized. One signal known to be critical for the regulation of granule exocytosis-mediated cytotoxicity in CD8+ T cells is Ag receptor-induced activation of protein kinase C (PKC). However, it is not known which step of the process is regulated by PKC. In addition, it has not been determined to date which of the PKC family members is required for the regulation of lytic granule exocytosis. By combination of pharmacological inhibitors and use of mice with targeted gene deletions, we show that PKCdelta is required for granule exocytosis-mediated lytic function in mouse CD8+ T cells. Our studies demonstrate that PKCdelta is required for lytic granule exocytosis, but is dispensable for activation, cytokine production, and expression of cytolytic molecules in response to TCR stimulation. Importantly, defective lytic function in PKCdelta-deficient cytotoxic lymphocytes is reversed by ectopic expression of PKCdelta. Finally, we show that PKCdelta is not involved in target cell-induced reorientation of the microtubule-organizing center, but is required for the subsequent exocytosis step, i.e., lytic granule polarization. Thus, our studies identify PKCdelta as a novel and selective regulator of Ag receptor-induced lytic granule polarization in mouse CD8+ T cells.
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Affiliation(s)
- Jennifer S Y Ma
- Center for Cancer and Immunology, Children's National Medical Center, Children's Research Institute, 111 Michigan Avenue NW, Washington, DC 20010, USA
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25
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Grybko MJ, Bartnik JP, Wurth GA, Pores-Fernando AT, Zweifach A. Calcineurin activation is only one calcium-dependent step in cytotoxic T lymphocyte granule exocytosis. J Biol Chem 2007; 282:18009-18017. [PMID: 17478429 DOI: 10.1074/jbc.m702222200] [Citation(s) in RCA: 15] [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
We have tested the idea that calcineurin, a calcium-dependent phosphatase that is critical for activating cytokine gene expression in helper T cells, plays a role in lytic granule exocytosis in cytotoxic T lymphocytes (CTLs). We used TALL-104 human leukemic CTLs as a model. Our results confirm an earlier report (Dutz, J. P., Fruman, D. A., Burakoff, S. J., and Bierer, B. E. (1993) J. Immunol. 150, 2591-2598) that immunosuppressive drugs inhibit exocytosis in CTLs stimulated either via the T cell receptor (TCR) or via TCR-independent soluble agents. Of the two recently reported alternate targets of immunosuppressive drugs (Matsuda, S., Shibasaki, F., Takehana, K., Mori, H., Nishida, E., and Koyasu, S. (2000) EMBO Rep. 1, 428-434 and Matsuda, S., and Koyasu, S. (2000) Immunopharmacology 47, 119-125), JNK is not required for lytic granule exocytosis, but we were not able to exclude a role for P38. Exocytosis could be inhibited by expressing GFP fused to a C-terminal fragment of CAIN (cabin 1), but not by expressing VIVIT-GFP. Finally, expressing either full-length or truncated constitutively active mutant calcineurin A enhanced lytic granule exocytosis. However, the mutant calcineurin was unable to support exocytosis when cells were stimulated in the absence of Ca2+ influx. Taken together, our results support the idea that activation of calcineurin is required for lytic granule exocytosis but suggest that it is not the sole Ca2+-dependent step.
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Affiliation(s)
- Michael J Grybko
- Department of Molecular and Cell Biology, University of Connecticut, Storrs, Connecticut 06268-3125
| | - Jakub P Bartnik
- Department of Molecular and Cell Biology, University of Connecticut, Storrs, Connecticut 06268-3125
| | - Georjeana A Wurth
- Department of Molecular and Cell Biology, University of Connecticut, Storrs, Connecticut 06268-3125
| | - Arun T Pores-Fernando
- Department of Molecular and Cell Biology, University of Connecticut, Storrs, Connecticut 06268-3125
| | - Adam Zweifach
- Department of Molecular and Cell Biology, University of Connecticut, Storrs, Connecticut 06268-3125.
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