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Turner ME, Che J, Mirhaidari GJM, Kennedy CC, Blum KM, Rajesh S, Zbinden JC, Breuer CK, Best CA, Barker JC. The lysosomal trafficking regulator "LYST": an 80-year traffic jam. Front Immunol 2024; 15:1404846. [PMID: 38774881 PMCID: PMC11106369 DOI: 10.3389/fimmu.2024.1404846] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2024] [Accepted: 04/17/2024] [Indexed: 05/24/2024] Open
Abstract
Lysosomes and lysosome related organelles (LROs) are dynamic organelles at the intersection of various pathways involved in maintaining cellular hemostasis and regulating cellular functions. Vesicle trafficking of lysosomes and LROs are critical to maintain their functions. The lysosomal trafficking regulator (LYST) is an elusive protein important for the regulation of membrane dynamics and intracellular trafficking of lysosomes and LROs. Mutations to the LYST gene result in Chédiak-Higashi syndrome, an autosomal recessive immunodeficiency characterized by defective granule exocytosis, cytotoxicity, etc. Despite eight decades passing since its initial discovery, a comprehensive understanding of LYST's function in cellular biology remains unresolved. Accumulating evidence suggests that dysregulation of LYST function also manifests in other disease states. Here, we review the available literature to consolidate available scientific endeavors in relation to LYST and discuss its relevance for immunomodulatory therapies, regenerative medicine and cancer applications.
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Affiliation(s)
- Mackenzie E. Turner
- Center for Regenerative Medicine, Abigail Wexner Research Institute at Nationwide Children’s Hospital, Columbus, OH, United States
- Molecular and Cellular Developmental Biology Graduate Program, The Ohio State University, Columbus, OH, United States
| | - Jingru Che
- Center for Regenerative Medicine, Abigail Wexner Research Institute at Nationwide Children’s Hospital, Columbus, OH, United States
| | - Gabriel J. M. Mirhaidari
- Center for Regenerative Medicine, Abigail Wexner Research Institute at Nationwide Children’s Hospital, Columbus, OH, United States
- The Ohio State University College of Medicine, Columbus, OH, United States
| | - Catherine C. Kennedy
- Center for Regenerative Medicine, Abigail Wexner Research Institute at Nationwide Children’s Hospital, Columbus, OH, United States
| | - Kevin M. Blum
- Center for Regenerative Medicine, Abigail Wexner Research Institute at Nationwide Children’s Hospital, Columbus, OH, United States
- The Ohio State University College of Medicine, Columbus, OH, United States
| | - Sahana Rajesh
- Center for Regenerative Medicine, Abigail Wexner Research Institute at Nationwide Children’s Hospital, Columbus, OH, United States
| | - Jacob C. Zbinden
- Center for Regenerative Medicine, Abigail Wexner Research Institute at Nationwide Children’s Hospital, Columbus, OH, United States
| | - Christopher K. Breuer
- Center for Regenerative Medicine, Abigail Wexner Research Institute at Nationwide Children’s Hospital, Columbus, OH, United States
| | - Cameron A. Best
- Center for Regenerative Medicine, Abigail Wexner Research Institute at Nationwide Children’s Hospital, Columbus, OH, United States
- Molecular and Cellular Developmental Biology Graduate Program, The Ohio State University, Columbus, OH, United States
| | - Jenny C. Barker
- Center for Regenerative Medicine, Abigail Wexner Research Institute at Nationwide Children’s Hospital, Columbus, OH, United States
- Department of Plastic and Reconstructive Surgery, The Ohio State University Medical Center, Columbus, OH, United States
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2
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Kuo WT, Kuo IY, Hsieh HC, Wu ST, Su WC, Wang YC. Rab37 mediates trafficking and membrane presentation of PD-1 to sustain T cell exhaustion in lung cancer. J Biomed Sci 2024; 31:20. [PMID: 38321486 PMCID: PMC10848371 DOI: 10.1186/s12929-024-01009-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2023] [Accepted: 01/29/2024] [Indexed: 02/08/2024] Open
Abstract
BACKGROUND Programmed cell death protein 1 (PD-1) is an immune checkpoint receptor expressed on the surface of T cells. High expression of PD-1 leads to T-cell dysfunction in the tumor microenvironment (TME). However, the mechanism of intracellular trafficking and plasma membrane presentation of PD-1 remains unclear. METHODS Multiple databases of lung cancer patients were integratively analyzed to screen Rab proteins and potential immune-related signaling pathways. Imaging and various biochemical assays were performed in Jurkat T cells, splenocytes, and human peripheral blood mononuclear cells (PBMCs). Rab37 knockout mice and specimens of lung cancer patients were used to validate the concept. RESULTS Here, we identify novel mechanisms of intracellular trafficking and plasma membrane presentation of PD-1 mediated by Rab37 small GTPase to sustain T cell exhaustion, thereby leading to poor patient outcome. PD-1 colocalized with Rab37-specific vesicles of T cells in a GTP-dependent manner whereby Rab37 mediated dynamic trafficking and membrane presentation of PD-1. However, glycosylation mutant PD-1 delayed cargo recruitment to the Rab37 vesicles, thus stalling membrane presentation. Notably, T cell proliferation and activity were upregulated in tumor-infiltrating T cells from the tumor-bearing Rab37 knockout mice compared to those from wild type. Clinically, the multiplex immunofluorescence-immunohistochemical assay indicated that patients with high Rab37+/PD-1+/TIM3+/CD8+ tumor infiltrating T cell profile correlated with advanced tumor stages and poor overall survival. Moreover, human PBMCs from patients demonstrated high expression of Rab37, which positively correlated with elevated levels of PD-1+ and TIM3+ in CD8+ T cells exhibiting reduced tumoricidal activity. CONCLUSIONS Our results provide the first evidence that Rab37 small GTPase mediates trafficking and membrane presentation of PD-1 to sustain T cell exhaustion, and the tumor promoting function of Rab37/PD-1 axis in T cells of TME in lung cancer. The expression profile of Rab37high/PD-1high/TIM3high in tumor-infiltrating CD8+ T cells is a biomarker for poor prognosis in lung cancer patients.
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Affiliation(s)
- Wan-Ting Kuo
- Department of Pharmacology, College of Medicine, National Cheng Kung University, No. 1, University Road, Tainan, 701, Taiwan
| | - I-Ying Kuo
- Department of Pharmacology, College of Medicine, National Cheng Kung University, No. 1, University Road, Tainan, 701, Taiwan
- Department of Biotechnology, College of Biomedical Science, Kaohsiung Medical University, Kaohsiung, Taiwan
| | - Hung-Chia Hsieh
- Institute of Basic Medicine, College of Medicine, National Cheng Kung University, Tainan, Taiwan
| | - Ssu-Ting Wu
- Department of Pharmacology, College of Medicine, National Cheng Kung University, No. 1, University Road, Tainan, 701, Taiwan
| | - Wu-Chou Su
- Division of Oncology, Department of Internal Medicine, College of Medicine, National Cheng Kung University, Tainan, Taiwan
| | - Yi-Ching Wang
- Department of Pharmacology, College of Medicine, National Cheng Kung University, No. 1, University Road, Tainan, 701, Taiwan.
- Institute of Basic Medicine, College of Medicine, National Cheng Kung University, Tainan, Taiwan.
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3
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Sekine T, Galgano D, Casoni GP, Meeths M, Cron RQ, Bryceson YT. CD8 + T Cell Biology in Cytokine Storm Syndromes. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2024; 1448:129-144. [PMID: 39117812 DOI: 10.1007/978-3-031-59815-9_10] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 08/10/2024]
Abstract
Familial forms of hemophagocytic lymphohistiocytosis (HLH) are caused by loss-of-function mutations in genes encoding perforin as well as those required for release of perforin-containing cytotoxic granule constituent. Perforin is expressed by subsets of CD8+ T cells and NK cells, representing lymphocytes that share mechanism of target cell killing yet display distinct modes of target cell recognition. Here, we highlight recent findings concerning the genetics of familial HLH that implicate CD8+ T cells in the pathogenesis of HLH and discuss mechanistic insights from animal models as well as patients that reveal how CD8+ T cells may contribute to or drive disease, at least in part through release of IFN-γ. Intriguingly, CD8+ T cells and NK cells may act differentially in severe hyperinflammatory diseases such as HLH. We also discuss how CD8+ T cells may promote or drive pathology in other cytokine release syndromes (CSS). Moreover, we review the molecular mechanisms underpinning CD8+ T cell-mediated lymphocyte cytotoxicity, key to the development of familial HLH. Together, recent insights to the pathophysiology of CSS in general and HLH in particular are providing promising new therapeutic targets.
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Affiliation(s)
- Takuya Sekine
- Center for Hematology and Regenerative Medicine, Department of Medicine, Karolinska Institutet, Stockholm, Sweden
| | - Donatella Galgano
- Center for Hematology and Regenerative Medicine, Department of Medicine, Karolinska Institutet, Stockholm, Sweden
| | - Giovanna P Casoni
- Center for Hematology and Regenerative Medicine, Department of Medicine, Karolinska Institutet, Stockholm, Sweden
| | - Marie Meeths
- Childhood Cancer Research Unit, Department of Women's and Children's Health, Karolinska Institutet, Karolinska University Hospital Solna, Stockholm, Sweden
- Clinical Genetics Unit, Department of Molecular Medicine and Surgery, and Center for Molecular Medicine, Karolinska Institutet, Karolinska University Hospital Solna, Stockholm, Sweden
| | - Randy Q Cron
- Division of Pediatric Rheumatology, University of Alabama at Birmingham Heersink School of Medicine, Birmingham, AL, USA
| | - Yenan T Bryceson
- Center for Hematology and Regenerative Medicine, Department of Medicine, Karolinska Institutet, Stockholm, Sweden.
- Broegelmann Research Laboratory, Department of Clinical Sciences, University of Bergen, Bergen, Norway.
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4
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Chang HF, Schirra C, Pattu V, Krause E, Becherer U. Lytic granule exocytosis at immune synapses: lessons from neuronal synapses. Front Immunol 2023; 14:1177670. [PMID: 37275872 PMCID: PMC10233144 DOI: 10.3389/fimmu.2023.1177670] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2023] [Accepted: 05/09/2023] [Indexed: 06/07/2023] Open
Abstract
Regulated exocytosis is a central mechanism of cellular communication. It is not only the basis for neurotransmission and hormone release, but also plays an important role in the immune system for the release of cytokines and cytotoxic molecules. In cytotoxic T lymphocytes (CTLs), the formation of the immunological synapse is required for the delivery of the cytotoxic substances such as granzymes and perforin, which are stored in lytic granules and released via exocytosis. The molecular mechanisms of their fusion with the plasma membrane are only partially understood. In this review, we discuss the molecular players involved in the regulated exocytosis of CTL, highlighting the parallels and differences to neuronal synaptic transmission. Additionally, we examine the strengths and weaknesses of both systems to study exocytosis.
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5
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Schirra C, Alawar N, Becherer U, Chang HF. Separation of Single Core and Multicore Lytic Granules by Subcellular Fractionation and Immunoisolation. Methods Mol Biol 2023; 2654:159-167. [PMID: 37106182 DOI: 10.1007/978-1-0716-3135-5_11] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/29/2023]
Abstract
Subcellular fractionation is an important tool used to separate intracellular organelles, structures or proteins. Here, we describe a stepwise protocol to isolate two types of lytic granules, multicore (MCG), and single core (SCG), from primary murine CTLs. We used cell disruption by nitrogen cavitation followed by separation of organelles via discontinuous sucrose density gradient centrifugation. Immunoisolation with a Synaptobrevin 2 antibody attached to magnetic beads was then used to harvest Synaptobrevin 2 positive granules for immunoblotting, mass spectrometry, electron, and light microscopy.
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Affiliation(s)
- Claudia Schirra
- Cellular Neurophysiology, Center for Integrative Physiology and Molecular Medicine (CIPMM), Saarland University, Homburg, Germany
| | - Nadia Alawar
- Cellular Neurophysiology, Center for Integrative Physiology and Molecular Medicine (CIPMM), Saarland University, Homburg, Germany
| | - Ute Becherer
- Cellular Neurophysiology, Center for Integrative Physiology and Molecular Medicine (CIPMM), Saarland University, Homburg, Germany
| | - Hsin-Fang Chang
- Cellular Neurophysiology, Center for Integrative Physiology and Molecular Medicine (CIPMM), Saarland University, Homburg, Germany.
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6
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Yan C, Jiang J, Yang Y, Geng X, Dong W. The function of VAMP2 in mediating membrane fusion: An overview. Front Mol Neurosci 2022; 15:948160. [PMID: 36618823 PMCID: PMC9816800 DOI: 10.3389/fnmol.2022.948160] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2022] [Accepted: 12/05/2022] [Indexed: 12/24/2022] Open
Abstract
Vesicle-associated membrane protein 2 (VAMP2, also known as synaptobrevin-2), encoded by VAMP2 in humans, is a key component of the soluble N-ethylmaleimide-sensitive factor attachment protein receptor (SNARE) complex. VAMP2 combined with syntaxin-1A (SYX-1A) and synaptosome-associated protein 25 (SNAP-25) produces a force that induces the formation of fusion pores, thereby mediating the fusion of synaptic vesicles and the release of neurotransmitters. VAMP2 is largely unstructured in the absence of interaction partners. Upon interaction with other SNAREs, the structure of VAMP2 stabilizes, resulting in the formation of four structural domains. In this review, we highlight the current knowledge of the roles of the VAMP2 domains and the interaction between VAMP2 and various fusion-related proteins in the presynaptic cytoplasm during the fusion process. Our summary will contribute to a better understanding of the roles of the VAMP2 protein in membrane fusion.
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Affiliation(s)
- Chong Yan
- Key Laboratory of Medical Electrophysiology, Ministry of Education and Medical Electrophysiological Key Laboratory of Sichuan Province, Institute of Cardiovascular Research, Southwest Medical University, Luzhou, Sichuan, China
| | - Jie Jiang
- Key Laboratory of Medical Electrophysiology, Ministry of Education and Medical Electrophysiological Key Laboratory of Sichuan Province, Institute of Cardiovascular Research, Southwest Medical University, Luzhou, Sichuan, China
| | - Yuan Yang
- Key Laboratory of Medical Electrophysiology, Ministry of Education and Medical Electrophysiological Key Laboratory of Sichuan Province, Institute of Cardiovascular Research, Southwest Medical University, Luzhou, Sichuan, China
| | - Xiaoqi Geng
- Department of Neurosurgery, Neurosurgical Clinical Research Center of Sichuan Province, Affiliated Hospital of Southwest Medical University, Luzhou, China,*Correspondence: Xiaoqi Geng,
| | - Wei Dong
- Key Laboratory of Medical Electrophysiology, Ministry of Education and Medical Electrophysiological Key Laboratory of Sichuan Province, Institute of Cardiovascular Research, Southwest Medical University, Luzhou, Sichuan, China,Wei Dong,
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7
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Ham H, Medlyn M, Billadeau DD. Locked and Loaded: Mechanisms Regulating Natural Killer Cell Lytic Granule Biogenesis and Release. Front Immunol 2022; 13:871106. [PMID: 35558071 PMCID: PMC9088006 DOI: 10.3389/fimmu.2022.871106] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2022] [Accepted: 03/29/2022] [Indexed: 11/22/2022] Open
Abstract
NK cell-mediated cytotoxicity is a critical element of our immune system required for protection from microbial infections and cancer. NK cells bind to and eliminate infected or cancerous cells via direct secretion of cytotoxic molecules toward the bound target cells. In this review, we summarize the current understanding of the molecular regulations of NK cell cytotoxicity, focusing on lytic granule development and degranulation processes. NK cells synthesize apoptosis-inducing proteins and package them into specialized organelles known as lytic granules (LGs). Upon activation of NK cells, LGs converge with the microtubule organizing center through dynein-dependent movement along microtubules, ultimately polarizing to the cytotoxic synapse where they subsequently fuse with the NK plasma membrane. From LGs biogenesis to degranulation, NK cells utilize several strategies to protect themselves from their own cytotoxic molecules. Additionally, molecular pathways that enable NK cells to perform serial killing are beginning to be elucidated. These advances in the understanding of the molecular pathways behind NK cell cytotoxicity will be important to not only improve current NK cell-based anti-cancer therapies but also to support the discovery of additional therapeutic opportunities.
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Affiliation(s)
- Hyoungjun Ham
- Division of Oncology Research, Mayo Clinic, Rochester, MN, United States
| | - Michael Medlyn
- Department of Immunology College of Medicine, Mayo Clinic, Rochester, MN, United States
| | - Daniel D Billadeau
- Division of Oncology Research, Mayo Clinic, Rochester, MN, United States.,Department of Immunology College of Medicine, Mayo Clinic, Rochester, MN, United States
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8
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Cassioli C, Baldari CT. The Expanding Arsenal of Cytotoxic T Cells. Front Immunol 2022; 13:883010. [PMID: 35514977 PMCID: PMC9065447 DOI: 10.3389/fimmu.2022.883010] [Citation(s) in RCA: 20] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2022] [Accepted: 03/21/2022] [Indexed: 01/13/2023] Open
Abstract
Cytotoxic T cells (CTLs) are the main cellular mediators of the adaptive immune defenses against intracellular pathogens and malignant cells. Upon recognition of specific antigen on their cellular target, CTLs assemble an immunological synapse where they mobilise their killing machinery that is released into the synaptic cleft to orchestrate the demise of their cell target. The arsenal of CTLs is stored in lysosome-like organelles that undergo exocytosis in response to signals triggered by the T cell antigen receptor following antigen recognition. These organelles include lytic granules carrying a cargo of cytotoxic proteins packed on a proteoglycan scaffold, multivesicular bodies carrying the death receptor ligand FasL, and the recently discovered supramolecular attack particles that carry a core of cytotoxic proteins encased in a non-membranous glycoprotein shell. Here we will briefly review the main features of these killing entities and discuss their interrelationship and interplay in CTL-mediated killing.
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Affiliation(s)
- Chiara Cassioli
- Department of Life Sciences, University of Siena, Siena, Italy
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9
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Staudt A, Ratai O, Bouzouina A, Fecher-Trost C, Shaaban A, Bzeih H, Horn A, Shaib AH, Klose M, Flockerzi V, Lauterbach MA, Rettig J, Becherer U. Localization of the Priming Factors CAPS1 and CAPS2 in Mouse Sensory Neurons Is Determined by Their N-Termini. Front Mol Neurosci 2022; 15:674243. [PMID: 35493323 PMCID: PMC9049930 DOI: 10.3389/fnmol.2022.674243] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2021] [Accepted: 02/09/2022] [Indexed: 11/13/2022] Open
Abstract
Both paralogs of the calcium-dependent activator protein for secretion (CAPS) are required for exocytosis of synaptic vesicles (SVs) and large dense core vesicles (LDCVs). Despite approximately 80% sequence identity, CAPS1 and CAPS2 have distinct functions in promoting exocytosis of SVs and LDCVs in dorsal root ganglion (DRG) neurons. However, the molecular mechanisms underlying these differences remain enigmatic. In this study, we applied high- and super-resolution imaging techniques to systematically assess the subcellular localization of CAPS paralogs in DRG neurons deficient in both CAPS1 and CAPS2. CAPS1 was found to be more enriched at the synapses. Using – in-depth sequence analysis, we identified a unique CAPS1 N-terminal sequence, which we introduced into CAPS2. This CAPS1/2 chimera reproduced the pre-synaptic localization of CAPS1 and partially rescued synaptic transmission in neurons devoid of CAPS1 and CAPS2. Using immunoprecipitation combined with mass spectrometry, we identified CAPS1-specific interaction partners that could be responsible for its pre-synaptic enrichment. Taken together, these data suggest an important role of the CAPS1-N terminus in the localization of the protein at pre-synapses.
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Affiliation(s)
- Angelina Staudt
- Department of Cellular Neurophysiology, Center for Integrative Physiology and Molecular Medicine, Saarland University, Homburg, Germany
| | - Olga Ratai
- Department of Cellular Neurophysiology, Center for Integrative Physiology and Molecular Medicine, Saarland University, Homburg, Germany
| | - Aicha Bouzouina
- Department of Cellular Neurophysiology, Center for Integrative Physiology and Molecular Medicine, Saarland University, Homburg, Germany
| | - Claudia Fecher-Trost
- Department of Experimental and Clinical Pharmacology and Toxicology, Preclinical Center for Molecular Signaling (PZMS), Saarland University, Homburg, Germany
| | - Ahmed Shaaban
- Department of Neuroscience, University of Copenhagen, København, Denmark
| | - Hawraa Bzeih
- Department of Cellular Neurophysiology, Center for Integrative Physiology and Molecular Medicine, Saarland University, Homburg, Germany
| | - Alexander Horn
- Department of Organic Chemistry, Saarland University, Saarbrücken, Germany
| | - Ali H. Shaib
- Department of Cellular Neurophysiology, Center for Integrative Physiology and Molecular Medicine, Saarland University, Homburg, Germany
- Institute for Neuro- and Sensory Physiology, University Medical Center Göttingen, Göttingen, Germany
| | - Margarete Klose
- Department of Cellular Neurophysiology, Center for Integrative Physiology and Molecular Medicine, Saarland University, Homburg, Germany
| | - Veit Flockerzi
- Department of Experimental and Clinical Pharmacology and Toxicology, Preclinical Center for Molecular Signaling (PZMS), Saarland University, Homburg, Germany
| | - Marcel A. Lauterbach
- Department of Molecular Imaging, Center for Integrative Physiology and Molecular Medicine, Saarland University, Homburg, Germany
| | - Jens Rettig
- Department of Cellular Neurophysiology, Center for Integrative Physiology and Molecular Medicine, Saarland University, Homburg, Germany
| | - Ute Becherer
- Department of Cellular Neurophysiology, Center for Integrative Physiology and Molecular Medicine, Saarland University, Homburg, Germany
- *Correspondence: Ute Becherer,
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10
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Chang HF, Schirra C, Ninov M, Hahn U, Ravichandran K, Krause E, Becherer U, Bálint Š, Harkiolaki M, Urlaub H, Valitutti S, Baldari CT, Dustin ML, Jahn R, Rettig J. Identification of distinct cytotoxic granules as the origin of supramolecular attack particles in T lymphocytes. Nat Commun 2022; 13:1029. [PMID: 35210420 PMCID: PMC8873490 DOI: 10.1038/s41467-022-28596-y] [Citation(s) in RCA: 23] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2021] [Accepted: 01/24/2022] [Indexed: 01/03/2023] Open
Abstract
Cytotoxic T lymphocytes (CTL) kill malignant and infected cells through the directed release of cytotoxic proteins into the immunological synapse (IS). The cytotoxic protein granzyme B (GzmB) is released in its soluble form or in supramolecular attack particles (SMAP). We utilize synaptobrevin2-mRFP knock-in mice to isolate fusogenic cytotoxic granules in an unbiased manner and visualize them alone or in degranulating CTLs. We identified two classes of fusion-competent granules, single core granules (SCG) and multi core granules (MCG), with different diameter, morphology and protein composition. Functional analyses demonstrate that both classes of granules fuse with the plasma membrane at the IS. SCG fusion releases soluble GzmB. MCGs can be labelled with the SMAP marker thrombospondin-1 and their fusion releases intact SMAPs. We propose that CTLs use SCG fusion to fill the synaptic cleft with active cytotoxic proteins instantly and parallel MCG fusion to deliver latent SMAPs for delayed killing of refractory targets.
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Affiliation(s)
- Hsin-Fang Chang
- Cellular Neurophysiology, Center for Integrative Physiology and Molecular Medicine (CIPMM), Saarland University, 66421, Homburg, Germany.
| | - Claudia Schirra
- Cellular Neurophysiology, Center for Integrative Physiology and Molecular Medicine (CIPMM), Saarland University, 66421, Homburg, Germany
| | - Momchil Ninov
- Bioanalytical Mass Spectrometry, Max Planck Institute for Multidisciplinary Sciences, Am Fassberg 11, 37077, Göttingen, Germany
- Laboratory of Neurobiology, Max Planck Institute for Multidisciplinary Sciences, Am Fassberg 11, 37077, Göttingen, Germany
- Bioanalytics, Institute for Clinical Chemistry, University Medical Center Göttingen, Robert Koch Str. 40, 37075, Göttingen, Germany
| | - Ulrike Hahn
- Cellular Neurophysiology, Center for Integrative Physiology and Molecular Medicine (CIPMM), Saarland University, 66421, Homburg, Germany
| | - Keerthana Ravichandran
- Cellular Neurophysiology, Center for Integrative Physiology and Molecular Medicine (CIPMM), Saarland University, 66421, Homburg, Germany
| | - Elmar Krause
- Cellular Neurophysiology, Center for Integrative Physiology and Molecular Medicine (CIPMM), Saarland University, 66421, Homburg, Germany
| | - Ute Becherer
- Cellular Neurophysiology, Center for Integrative Physiology and Molecular Medicine (CIPMM), Saarland University, 66421, Homburg, Germany
| | - Štefan Bálint
- Kennedy Institute of Rheumatology, Nuffield Department of Orthopaedics, Rheumatology and Musculoskeletal Sciences, University of Oxford, OX3 7FY, Oxford, UK
| | - Maria Harkiolaki
- Diamond Light Source, Harwell Science and Innovation Campus, OX11 0DE, Didcot, UK
| | - Henning Urlaub
- Bioanalytical Mass Spectrometry, Max Planck Institute for Multidisciplinary Sciences, Am Fassberg 11, 37077, Göttingen, Germany
- Bioanalytics, Institute for Clinical Chemistry, University Medical Center Göttingen, Robert Koch Str. 40, 37075, Göttingen, Germany
| | - Salvatore Valitutti
- Cancer Research Center of Toulouse, INSERM U1037, 31037, Toulouse, France
- Department of Pathology, Institut Universitaire du Cancer-Oncopole de Toulouse, Toulouse, France
| | - Cosima T Baldari
- Department of Life Sciences, University of Siena, 53100, Siena, Italy
| | - Michael L Dustin
- Kennedy Institute of Rheumatology, Nuffield Department of Orthopaedics, Rheumatology and Musculoskeletal Sciences, University of Oxford, OX3 7FY, Oxford, UK
| | - Reinhard Jahn
- Laboratory of Neurobiology, Max Planck Institute for Multidisciplinary Sciences, Am Fassberg 11, 37077, Göttingen, Germany
| | - Jens Rettig
- Cellular Neurophysiology, Center for Integrative Physiology and Molecular Medicine (CIPMM), Saarland University, 66421, Homburg, Germany.
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11
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Jiang H, Esparza TJ, Kummer TT, Brody DL. Unbiased high-content screening reveals Aβ- and tau-independent synaptotoxic activities in human brain homogenates from Alzheimer's patients and high-pathology controls. PLoS One 2021; 16:e0259335. [PMID: 34748596 PMCID: PMC8575250 DOI: 10.1371/journal.pone.0259335] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2021] [Accepted: 10/19/2021] [Indexed: 11/22/2022] Open
Abstract
Alzheimer’s disease (AD) is tightly correlated with synapse loss in vulnerable brain regions. It is assumed that specific molecular entities such as Aβ and tau cause synapse loss in AD, yet unbiased screens for synaptotoxic activities have not been performed. Here, we performed size exclusion chromatography on soluble human brain homogenates from AD cases, high pathology non-demented controls, and low pathology age-matched controls using our novel high content primary cultured neuron-based screening assay. Both presynaptic and postsynaptic toxicities were elevated in homogenates from AD cases and high pathology non-demented controls to a similar extent, with more modest synaptotoxic activities in homogenates from low pathology normal controls. Surprisingly, synaptotoxic activities were found in size fractions peaking between the 17–44 kDa size standards that did not match well with Aβ and tau immunoreactive species in these homogenates. The fractions containing previously identified high molecular weight soluble amyloid beta aggregates/”oligomers” were non-toxic in this assay. Furthermore, immunodepletion of Aβ and tau did not reduce synaptotoxic activity. This result contrasts with previous findings involving the same methods applied to 3xTg-AD mouse brain extracts. The nature of the synaptotoxic species has not been identified. Overall, our data indicates one or more potential Aβ and tau independent synaptotoxic activities in human AD brain homogenates. This result aligns well with the key role of synaptic loss in the early cognitive decline and may provide new insight into AD pathophysiology.
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Affiliation(s)
- Hao Jiang
- Department of Neurology, Washington University School of Medicine, St Louis, Missouri, United States of America
| | - Thomas J. Esparza
- Department of Neurology, Washington University School of Medicine, St Louis, Missouri, United States of America
- Henry M Jackson Foundation for the Advancement of Military Medicine, Bethesda, Maryland, United States of America
- National Institute of Neurological Disorders and Stroke, Bethesda, Maryland, United States of America
| | - Terrance T. Kummer
- Department of Neurology, Washington University School of Medicine, St Louis, Missouri, United States of America
| | - David L. Brody
- Department of Neurology, Washington University School of Medicine, St Louis, Missouri, United States of America
- National Institute of Neurological Disorders and Stroke, Bethesda, Maryland, United States of America
- Department of Neurology, Uniformed Services University of the Health Sciences, Bethesda, Maryland, United States of America
- * E-mail:
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12
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Meeths M, Bryceson YT. Genetics and pathophysiology of haemophagocytic lymphohistiocytosis. Acta Paediatr 2021; 110:2903-2911. [PMID: 34192386 DOI: 10.1111/apa.16013] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/25/2021] [Revised: 06/21/2021] [Accepted: 06/29/2021] [Indexed: 12/11/2022]
Abstract
Haemophagocytic lymphohistiocytosis (HLH) represents a life-threatening hyperinflammatory syndrome. Familial studies have established autosomal and X-linked recessive causes of HLH, highlighting a pivotal role for lymphocyte cytotoxicity in the control of certain virus infections and immunoregulation. Recently, a more complex etiological framework has emerged, linking HLH predisposition to variants in genes required for metabolism or immunity to intracellular pathogens. We review genetic predisposition to HLH and discuss how molecular insights have provided fundamental knowledge of the immune system as well as detailed pathophysiological understanding of hyperinflammatory diseases, highlighting new treatment strategies.
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Affiliation(s)
- Marie Meeths
- Childhood Cancer Research Unit Department of Women’s and Children’s Health Karolinska Institutet Stockholm Sweden
- Theme of Children’s Health Karolinska University Hospital Stockholm Sweden
| | - Yenan T. Bryceson
- Centre for Hematology and Regenerative Medicine Department of Medicine Karolinska Institute Stockholm Sweden
- Division of Clinical Immunology and Transfusion Medicine Karolinska University Hospital Stockholm Sweden
- Broegelmann Research Laboratory Department of Clinical Sciences University of Bergen Bergen Norway
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13
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Yapici-Eser H, Koroglu YE, Oztop-Cakmak O, Keskin O, Gursoy A, Gursoy-Ozdemir Y. Neuropsychiatric Symptoms of COVID-19 Explained by SARS-CoV-2 Proteins' Mimicry of Human Protein Interactions. Front Hum Neurosci 2021; 15:656313. [PMID: 33833673 PMCID: PMC8021734 DOI: 10.3389/fnhum.2021.656313] [Citation(s) in RCA: 35] [Impact Index Per Article: 11.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2021] [Accepted: 02/23/2021] [Indexed: 12/16/2022] Open
Abstract
The first clinical symptoms focused on the presentation of coronavirus disease 2019 (COVID-19) have been respiratory failure, however, accumulating evidence also points to its presentation with neuropsychiatric symptoms, the exact mechanisms of which are not well known. By using a computational methodology, we aimed to explain the molecular paths of COVID-19 associated neuropsychiatric symptoms, based on the mimicry of the human protein interactions with SARS-CoV-2 proteins. Methods: Available 11 of the 29 SARS-CoV-2 proteins' structures have been extracted from Protein Data Bank. HMI-PRED (Host-Microbe Interaction PREDiction), a recently developed web server for structural PREDiction of protein-protein interactions (PPIs) between host and any microbial species, was used to find the "interface mimicry" through which the microbial proteins hijack host binding surfaces. Classification of the found interactions was conducted using the PANTHER Classification System. Results: Predicted Human-SARS-CoV-2 protein interactions have been extensively compared with the literature. Based on the analysis of the molecular functions, cellular localizations and pathways related to human proteins, SARS-CoV-2 proteins are found to possibly interact with human proteins linked to synaptic vesicle trafficking, endocytosis, axonal transport, neurotransmission, growth factors, mitochondrial and blood-brain barrier elements, in addition to its peripheral interactions with proteins linked to thrombosis, inflammation and metabolic control. Conclusion: SARS-CoV-2-human protein interactions may lead to the development of delirium, psychosis, seizures, encephalitis, stroke, sensory impairments, peripheral nerve diseases, and autoimmune disorders. Our findings are also supported by the previous in vivo and in vitro studies from other viruses. Further in vivo and in vitro studies using the proteins that are pointed here, could pave new targets both for avoiding and reversing neuropsychiatric presentations.
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Affiliation(s)
- Hale Yapici-Eser
- Department of Psychiatry, School of Medicine, Koç University, Istanbul, Turkey
- Research Center for Translational Medicine, Koç University, Istanbul, Turkey
| | - Yunus Emre Koroglu
- Research Center for Translational Medicine, Koç University, Istanbul, Turkey
- Graduate School of Sciences and Engineering, College of Engineering, Koç University, Istanbul, Turkey
| | - Ozgur Oztop-Cakmak
- Research Center for Translational Medicine, Koç University, Istanbul, Turkey
- Department of Neurology, School of Medicine, Koç University, Istanbul, Turkey
| | - Ozlem Keskin
- Research Center for Translational Medicine, Koç University, Istanbul, Turkey
- College of Engineering, Chemical and Biological Engineering, Koç University, Istanbul, Turkey
| | - Attila Gursoy
- Research Center for Translational Medicine, Koç University, Istanbul, Turkey
- Department of Computer Science and Engineering, College of Engineering, Koç University, Istanbul, Turkey
| | - Yasemin Gursoy-Ozdemir
- Research Center for Translational Medicine, Koç University, Istanbul, Turkey
- Department of Neurology, School of Medicine, Koç University, Istanbul, Turkey
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14
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Tang BL. SNAREs and developmental disorders. J Cell Physiol 2020; 236:2482-2504. [PMID: 32959907 DOI: 10.1002/jcp.30067] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2020] [Revised: 08/20/2020] [Accepted: 09/09/2020] [Indexed: 12/12/2022]
Abstract
Members of the soluble N-ethylmaleimide-sensitive factor attachment protein receptor (SNARE) family mediate membrane fusion processes associated with vesicular trafficking and autophagy. SNAREs mediate core membrane fusion processes essential for all cells, but some SNAREs serve cell/tissue type-specific exocytic/endocytic functions, and are therefore critical for various aspects of embryonic development. Mutations or variants of their encoding genes could give rise to developmental disorders, such as those affecting the nervous system and immune system in humans. Mutations to components in the canonical synaptic vesicle fusion SNARE complex (VAMP2, STX1A/B, and SNAP25) and a key regulator of SNARE complex formation MUNC18-1, produce variant phenotypes of autism, intellectual disability, movement disorders, and epilepsy. STX11 and MUNC18-2 mutations underlie 2 subtypes of familial hemophagocytic lymphohistiocytosis. STX3 mutations contribute to variant microvillus inclusion disease. Chromosomal microdeletions involving STX16 play a role in pseudohypoparathyroidism type IB associated with abnormal imprinting of the GNAS complex locus. In this short review, I discuss these and other SNARE gene mutations and variants that are known to be associated with a variety developmental disorders, with a focus on their underlying cellular and molecular pathological basis deciphered through disease modeling. Possible pathogenic potentials of other SNAREs whose variants could be disease predisposing are also speculated upon.
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Affiliation(s)
- Bor L Tang
- Department of Biochemistry, Yong Loo Lin School of Medicine, National University of Singapore, Singapore
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15
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Chitirala P, Chang HF, Martzloff P, Harenberg C, Ravichandran K, Abdulreda MH, Berggren PO, Krause E, Schirra C, Leinders-Zufall T, Benseler F, Brose N, Rettig J. Studying the biology of cytotoxic T lymphocytes in vivo with a fluorescent granzyme B-mTFP knock-in mouse. eLife 2020; 9:e58065. [PMID: 32696761 PMCID: PMC7375811 DOI: 10.7554/elife.58065] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2020] [Accepted: 07/01/2020] [Indexed: 12/23/2022] Open
Abstract
Understanding T cell function in vivo is of key importance for basic and translational immunology alike. To study T cells in vivo, we developed a new knock-in mouse line, which expresses a fusion protein of granzyme B, a key component of cytotoxic granules involved in T cell-mediated target cell-killing, and monomeric teal fluorescent protein from the endogenous Gzmb locus. Homozygous knock-ins, which are viable and fertile, have cytotoxic T lymphocytes with endogeneously fluorescent cytotoxic granules but wild-type-like killing capacity. Expression of the fluorescent fusion protein allows quantitative analyses of cytotoxic granule maturation, transport and fusion in vitro with super-resolution imaging techniques, and two-photon microscopy in living knock-ins enables the visualization of tissue rejection through individual target cell-killing events in vivo. Thus, the new mouse line is an ideal tool to study cytotoxic T lymphocyte biology and to optimize personalized immunotherapy in cancer treatment.
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Affiliation(s)
- Praneeth Chitirala
- Cellular Neurophysiology, Center for Integrative Physiology and Molecular Medicine (CIPMM), Saarland UniversityHomburgGermany
| | - Hsin-Fang Chang
- Cellular Neurophysiology, Center for Integrative Physiology and Molecular Medicine (CIPMM), Saarland UniversityHomburgGermany
| | - Paloma Martzloff
- Cellular Neurophysiology, Center for Integrative Physiology and Molecular Medicine (CIPMM), Saarland UniversityHomburgGermany
| | - Christiane Harenberg
- Department of Molecular Neurobiology, Max-Planck-Institute of Experimental MedicineGöttingenGermany
| | - Keerthana Ravichandran
- Cellular Neurophysiology, Center for Integrative Physiology and Molecular Medicine (CIPMM), Saarland UniversityHomburgGermany
| | - Midhat H Abdulreda
- Diabetes Research Institute and Cell Transplant Center, University of Miami Miller School of MedicineMiamiUnited States
- Department of Surgery, University of Miami Miller School of MedicineMiamiUnited States
- Department of Microbiology and Immunology, University of Miami Miller School of MedicineMiamiUnited States
- Department of Ophthalmology, University of Miami Miller School of MedicineMiamiUnited States
| | - Per-Olof Berggren
- Diabetes Research Institute and Cell Transplant Center, University of Miami Miller School of MedicineMiamiUnited States
- Department of Surgery, University of Miami Miller School of MedicineMiamiUnited States
- Diabetes Research Institute FederationHollywoodUnited States
- The Rolf Luft Research Center for Diabetes and Endocrinology, Karolinska Institutet, Karolinska University HospitalStockholmSweden
| | - Elmar Krause
- Cellular Neurophysiology, Center for Integrative Physiology and Molecular Medicine (CIPMM), Saarland UniversityHomburgGermany
| | - Claudia Schirra
- Cellular Neurophysiology, Center for Integrative Physiology and Molecular Medicine (CIPMM), Saarland UniversityHomburgGermany
| | - Trese Leinders-Zufall
- Sensory and Neuroendocrine Physiology, Center for Integrative Physiology and Molecular Medicine (CIPMM), Saarland UniversityHomburgGermany
| | - Fritz Benseler
- Department of Molecular Neurobiology, Max-Planck-Institute of Experimental MedicineGöttingenGermany
| | - Nils Brose
- Department of Molecular Neurobiology, Max-Planck-Institute of Experimental MedicineGöttingenGermany
| | - Jens Rettig
- Cellular Neurophysiology, Center for Integrative Physiology and Molecular Medicine (CIPMM), Saarland UniversityHomburgGermany
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16
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Sauerbeck AD, Gangolli M, Reitz SJ, Salyards MH, Kim SH, Hemingway C, Gratuze M, Makkapati T, Kerschensteiner M, Holtzman DM, Brody DL, Kummer TT. SEQUIN Multiscale Imaging of Mammalian Central Synapses Reveals Loss of Synaptic Connectivity Resulting from Diffuse Traumatic Brain Injury. Neuron 2020; 107:257-273.e5. [PMID: 32392471 PMCID: PMC7381374 DOI: 10.1016/j.neuron.2020.04.012] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2019] [Revised: 03/04/2020] [Accepted: 04/11/2020] [Indexed: 02/07/2023]
Abstract
The brain's complex microconnectivity underlies its computational abilities and vulnerability to injury and disease. It has been challenging to illuminate the features of this synaptic network due to the small size and dense packing of its elements. Here, we describe a rapid, accessible super-resolution imaging and analysis workflow-SEQUIN-that quantifies central synapses in human tissue and animal models, characterizes their nanostructural and molecular features, and enables volumetric imaging of mesoscale synaptic networks without the production of large histological arrays. Using SEQUIN, we identify cortical synapse loss resulting from diffuse traumatic brain injury, a highly prevalent connectional disorder. Similar synapse loss is observed in three murine models of Alzheimer-related neurodegeneration, where SEQUIN mesoscale mapping identifies regional synaptic vulnerability. These results establish an easily implemented and robust nano-to-mesoscale synapse quantification and characterization method. They furthermore identify a shared mechanism-synaptopathy-between Alzheimer neurodegeneration and its best-established epigenetic risk factor, brain trauma.
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Affiliation(s)
- Andrew D Sauerbeck
- Department of Neurology, Hope Center for Neurological Disorders, Knight Alzheimer's Disease Research Center, Washington University School of Medicine, St. Louis, MO 63110, USA
| | - Mihika Gangolli
- McKelvey School of Engineering, Washington University, St. Louis, MO 63130, USA; Currently, Center for Neuroscience and Regenerative Medicine, Uniformed Services University of the Health Sciences, Bethesda, MD 20814, USA
| | - Sydney J Reitz
- Department of Neurology, Hope Center for Neurological Disorders, Knight Alzheimer's Disease Research Center, Washington University School of Medicine, St. Louis, MO 63110, USA
| | - Maverick H Salyards
- Department of Neurology, Hope Center for Neurological Disorders, Knight Alzheimer's Disease Research Center, Washington University School of Medicine, St. Louis, MO 63110, USA
| | - Samuel H Kim
- Department of Neurology, Hope Center for Neurological Disorders, Knight Alzheimer's Disease Research Center, Washington University School of Medicine, St. Louis, MO 63110, USA
| | - Christopher Hemingway
- Institute of Clinical Neuroimmunology, Ludwig-Maximilians Universität München, Munich 82152, Germany
| | - Maud Gratuze
- Department of Neurology, Hope Center for Neurological Disorders, Knight Alzheimer's Disease Research Center, Washington University School of Medicine, St. Louis, MO 63110, USA
| | - Tejaswi Makkapati
- Department of Neurology, Hope Center for Neurological Disorders, Knight Alzheimer's Disease Research Center, Washington University School of Medicine, St. Louis, MO 63110, USA
| | - Martin Kerschensteiner
- Institute of Clinical Neuroimmunology, Ludwig-Maximilians Universität München, Munich 82152, Germany; Munich Cluster of Systems Neurology (SyNergy), Munich 81377, Germany
| | - David M Holtzman
- Department of Neurology, Hope Center for Neurological Disorders, Knight Alzheimer's Disease Research Center, Washington University School of Medicine, St. Louis, MO 63110, USA
| | - David L Brody
- Department of Neurology, Hope Center for Neurological Disorders, Knight Alzheimer's Disease Research Center, Washington University School of Medicine, St. Louis, MO 63110, USA; Currently, Center for Neuroscience and Regenerative Medicine, Uniformed Services University of the Health Sciences, Bethesda, MD 20814, USA
| | - Terrance T Kummer
- Department of Neurology, Hope Center for Neurological Disorders, Knight Alzheimer's Disease Research Center, Washington University School of Medicine, St. Louis, MO 63110, USA.
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17
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Rettig J, Baldari CT. SMAPs: sweet carriers of lethal cargo for CTL-mediated killing. Immunol Cell Biol 2020; 98:524-527. [PMID: 32648284 DOI: 10.1111/imcb.12367] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Jens Rettig
- Department of Physiology, Saarland University, Homburg, Germany
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18
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Sleiman M, Stevens DR, Chitirala P, Rettig J. Cytotoxic Granule Trafficking and Fusion in Synaptotagmin7-Deficient Cytotoxic T Lymphocytes. Front Immunol 2020; 11:1080. [PMID: 32547563 PMCID: PMC7273742 DOI: 10.3389/fimmu.2020.01080] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2020] [Accepted: 05/05/2020] [Indexed: 11/13/2022] Open
Abstract
Granules of cytotoxic T lymphocytes (CTL) are derived from the lysosomal compartment. Synaptotagmin7 (Syt7) appears to be the calcium sensor triggering fusion of lysosomes in fibroblasts. Syt7 has been proposed to control cytotoxic granule (CG) fusion in lymphocytes and mice lacking Syt7 have reduced ability to clear infections. However, fusion of CG persists in the absence of Syt7. To clarify the role of Syt7 in CTL function, we have examined the fusion of cytotoxic granules of CD8+ T-lymphocytes from Syt7 knock-out mice. We have recorded granule fusion in living CTL, using total internal reflection microscopy. Since Syt7 is considered a high affinity calcium-sensor specialized for fusion under low calcium conditions, we have compared cytotoxic granule fusion under low and high calcium conditions in the same CTL. There was no difference in latencies or numbers of fusion events per CTL under low-calcium conditions, indicating that Syt7 is not required for cytotoxic granule fusion. A deficit of fusion in Syt7 KO CTL was seen when a high-calcium solution was introduced. Expressing wild type Syt7 in Syt7 KO lymphocytes reversed this deficit, confirming its Syt7-dependence. Mutations of Syt7 which disrupt calcium binding to its C2A domain reduced the efficacy of this rescue. We counted the cytotoxic granules present at the plasma membrane to determine if the lack of fusion events in the Syt7 KO CTL was due to a lack of granules. In low calcium there were no differences in fusion events per CTL, and granule numbers were similar. In high calcium, granule number was similar though wild type CTL exhibited significantly more fusion than Syt7 KO CTL. The modest differences in granule counts do not account for the lack of fusion in high calcium in Syt7 KO CTL. In Syt7 KO CTL expressing wild type Syt7, delivery of cytotoxic granules to the plasma membrane was comparable to that of wild type CTL. Syt7 KO CTL expressing Syt7 with deficient calcium binding in the C2A domain had significantly less fusion and fewer CG at the plasma membrane. These results indicate that Syt7 is involved in trafficking of CG to the plasma membrane.
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Affiliation(s)
- Marwa Sleiman
- Cellular Neurophysiology, Center for Integrative Physiology and Molecular Medicine (CIPMM), Saarland University, Homburg, Germany
| | - David R Stevens
- Cellular Neurophysiology, Center for Integrative Physiology and Molecular Medicine (CIPMM), Saarland University, Homburg, Germany
| | - Praneeth Chitirala
- Cellular Neurophysiology, Center for Integrative Physiology and Molecular Medicine (CIPMM), Saarland University, Homburg, Germany
| | - Jens Rettig
- Cellular Neurophysiology, Center for Integrative Physiology and Molecular Medicine (CIPMM), Saarland University, Homburg, Germany
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19
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Chitirala P, Ravichandran K, Schirra C, Chang HF, Krause E, Kazmaier U, Lauterbach MA, Rettig J. Role of V-ATPase a3-Subunit in Mouse CTL Function. THE JOURNAL OF IMMUNOLOGY 2020; 204:2818-2828. [PMID: 32269094 DOI: 10.4049/jimmunol.1901536] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/31/2019] [Accepted: 02/26/2020] [Indexed: 12/17/2022]
Abstract
CTLs release cytotoxic proteins such as granzymes and perforin through fusion of cytotoxic granules (CG) at the target cell interface, the immune synapse, to kill virus-infected and tumorigenic target cells. A characteristic feature of these granules is their acidic pH inside the granule lumen, which is required to process precursors of granzymes and perforin to their mature form. However, the role of acidic pH in CG maturation, transport, and fusion is not understood. We demonstrate in primary murine CTLs that the a3-subunit of the vacuolar-type (H+)-adenosine triphosphatase is required for establishing a luminal pH of 6.1 inside CG using ClopHensorN(Q69M), a newly generated CG-specific pH indicator. Knockdown of the a3-subunit resulted in a significantly reduced killing of target cells and a >50% reduction in CG fusion in total internal reflection fluorescence microscopy, which was caused by a reduced number of CG at the immune synapse. Superresolution microscopy revealed a reduced interaction of CG with the microtubule network upon a3-subunit knockdown. Finally, we find by electron and structured illumination microscopy that knockdown of the a3-subunit altered the diameter and density of individual CG, whereas the number of CG per CTL was unaffected. We conclude that the a3-subunit of the vacuolar adenosine triphosphatase is not only responsible for the acidification of CG, but also contributes to the maturation and efficient transport of the CG to the immune synapse.
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Affiliation(s)
- Praneeth Chitirala
- Cellular Neurophysiology, Center for Integrative Physiology and Molecular Medicine, Saarland University, 66421 Homburg, Germany
| | - Keerthana Ravichandran
- Cellular Neurophysiology, Center for Integrative Physiology and Molecular Medicine, Saarland University, 66421 Homburg, Germany
| | - Claudia Schirra
- Cellular Neurophysiology, Center for Integrative Physiology and Molecular Medicine, Saarland University, 66421 Homburg, Germany
| | - Hsin-Fang Chang
- Cellular Neurophysiology, Center for Integrative Physiology and Molecular Medicine, Saarland University, 66421 Homburg, Germany
| | - Elmar Krause
- Cellular Neurophysiology, Center for Integrative Physiology and Molecular Medicine, Saarland University, 66421 Homburg, Germany
| | - Uli Kazmaier
- Organic Chemistry, Saarland University, 66123 Saarbrücken, Germany; and
| | - Marcel A Lauterbach
- Molecular Imaging, Center for Integrative Physiology and Molecular Medicine, Saarland University, 66421 Homburg, Germany
| | - Jens Rettig
- Cellular Neurophysiology, Center for Integrative Physiology and Molecular Medicine, Saarland University, 66421 Homburg, Germany;
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20
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Various Stages of Immune Synapse Formation Are Differently Dependent on the Strength of the TCR Stimulus. Int J Mol Sci 2020; 21:ijms21072475. [PMID: 32252488 PMCID: PMC7177831 DOI: 10.3390/ijms21072475] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/29/2020] [Revised: 03/23/2020] [Accepted: 03/31/2020] [Indexed: 12/13/2022] Open
Abstract
Cytotoxic T lymphocytes (CTL) are key players of the adaptive immune system that target tumors and infected cells. A central step to that is the formation of a cell–cell contact zone between the CTL and its target called an immune synapse (IS). Here, we investigate the influence of the initial T cell receptor (TCR) trigger of a cytolytic IS on the distinct steps leading to cytotoxic granule (CG) exocytosis. We stimulated primary CTLs from mouse using lipid bilayers with varying anti-CD3 but constant ICAM concentrations. We fluorescently labeled molecular markers of distinct IS zones such as actin, CD3, granzyme B, and Synaptobrevin2 in CTLs and imaged cytolytic IS formation by total internal reflection fluorescence microscopy (TIRFM). We found that an intermediate anti-CD3 concentration of 10 µg/mL induces the fastest adhesion of CTLs to the bilayers and results in maximal CG fusion efficiency. The latency of actin ring formation, dwell time, and maximum surface area at the IS exhibit different dependencies on the stimulatory anti-CD3 concentrations. The number and surface area of CD3 clusters at the IS seem to show a different dependency to the TCR trigger when compared to their dwell time. Finally, the mode of full CG exocytosis appears to be independent of the TCR trigger.
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21
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Jiang H, Esparza TJ, Kummer TT, Zhong H, Rettig J, Brody DL. Live Neuron High-Content Screening Reveals Synaptotoxic Activity in Alzheimer Mouse Model Homogenates. Sci Rep 2020; 10:3412. [PMID: 32098978 PMCID: PMC7042280 DOI: 10.1038/s41598-020-60118-y] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2019] [Accepted: 02/05/2020] [Indexed: 12/28/2022] Open
Abstract
Accurate quantification of synaptic changes is essential for understanding the molecular mechanisms of synaptogenesis, synaptic plasticity, and synaptic toxicity. Here we demonstrate a robust high-content imaging method for the assessment of synaptic changes and apply the method to brain homogenates from an Alzheimer's disease mouse model. Our method uses serial imaging of endogenous fluorescent labeled presynaptic VAMP2 and postsynaptic PSD95 in long-term cultured live primary neurons in 96 well microplates, and uses automatic image analysis to quantify the number of colocalized mature synaptic puncta for the assessment of synaptic changes in live neurons. As a control, we demonstrated that our synaptic puncta assay is at least 10-fold more sensitive to the toxic effects of glutamate than the MTT assay. Using our assay, we have compared synaptotoxic activities in size-exclusion chromatography fractioned protein samples from 3xTg-AD mouse model brain homogenates. Multiple synaptotoxic activities were found in high and low molecular weight fractions. Amyloid-beta immunodepletion alleviated some but not all of the synaptotoxic activities. Although the biochemical entities responsible for the synaptotoxic activities have yet to be determined, these proof-of-concept results demonstrate that this novel assay may have many potential mechanistic and therapeutic applications.
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Affiliation(s)
- Hao Jiang
- Department of Neurology, Washington University School of Medicine, 660 South Euclid Avenue, Box 8111, St Louis, Missouri, 63110, USA
| | - Thomas J Esparza
- Department of Neurology, Washington University School of Medicine, 660 South Euclid Avenue, Box 8111, St Louis, Missouri, 63110, USA
- Henry M Jackson Foundation for the Advancement of Military Medicine, Bethesda, Maryland, 20817, USA
- National Institute of Neurological Disorders and Stroke, 10 Center Drive, Bethesda, Maryland, 20892, USA
| | - Terrance T Kummer
- Department of Neurology, Washington University School of Medicine, 660 South Euclid Avenue, Box 8111, St Louis, Missouri, 63110, USA
| | - Haining Zhong
- Vollum Institute, Oregon Health and Science University, 3181 SW Sam Jackson Park Rd, Portland, Oregon, 97239, USA
| | - Jens Rettig
- Department of Physiology, Saarland University, Center for Integrative Physiology and Molecular Medicine (CIPMM), Building 48, Homburg, 66421, Germany
| | - David L Brody
- Department of Neurology, Washington University School of Medicine, 660 South Euclid Avenue, Box 8111, St Louis, Missouri, 63110, USA.
- National Institute of Neurological Disorders and Stroke, 10 Center Drive, Bethesda, Maryland, 20892, USA.
- Department of Neurology, Uniformed Services University of the Health Sciences, Bethesda, Maryland, 20814, USA.
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22
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Phatarpekar PV, Billadeau DD. Molecular regulation of the plasma membrane-proximal cellular steps involved in NK cell cytolytic function. J Cell Sci 2020; 133:133/5/jcs240424. [PMID: 32086255 DOI: 10.1242/jcs.240424] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
Natural killer (NK) cells, cytolytic lymphocytes of the innate immune system, play a crucial role in the immune response against infection and cancer. NK cells kill target cells through exocytosis of lytic granules that contain cytotoxic proteins, such as perforin and granzymes. Formation of a functional immune synapse, i.e. the interface between the NK cell and its target cell enhances lysis through accumulation of polymerized F-actin at the NK cell synapse, leading to convergence of lytic granules to the microtubule organizing center (MTOC) and its subsequent polarization along microtubules to deliver the lytic granules to the synapse. In this review, we focus on the molecular mechanisms regulating the cellular processes that occur after the lytic granules are delivered to the cytotoxic synapse. We outline how - once near the synapse - the granules traverse the clearings created by F-actin remodeling to dock, tether and fuse with the plasma membrane in order to secrete their lytic content into the synaptic cleft through exocytosis. Further emphasis is given to the role of Ca2+ mobilization during degranulation and, whenever applicable, we compare these mechanisms in NK cells and cytotoxic T lymphocytes (CTLs) as adaptive immune system effectors.
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Affiliation(s)
- Prasad V Phatarpekar
- Department of Immunology, Mayo Clinic College of Medicine, Rochester, MN 55905, USA
| | - Daniel D Billadeau
- Department of Immunology, Mayo Clinic College of Medicine, Rochester, MN 55905, USA
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23
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Pei Y, Maitta RW. Alpha synuclein in hematopoiesis and immunity. Heliyon 2019; 5:e02590. [PMID: 31692680 PMCID: PMC6806402 DOI: 10.1016/j.heliyon.2019.e02590] [Citation(s) in RCA: 36] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2019] [Revised: 09/13/2019] [Accepted: 10/02/2019] [Indexed: 12/15/2022] Open
Abstract
Parkinson's disease (PD) is the second most common neurodegenerative condition and intracellular deposition of Lewy bodies in the substantia nigra (SN), which can cause dopaminergic neuronal death, is the hallmark of this syndrome. α-synuclein (syn) is a small protein expressed mainly in neurons but can also be found in a number of tissues. It can be present as a soluble monomer under normal physiological conditions, but can be toxic in its oligomeric or fibrillary forms. Most of the available literature has focused on the effects of α-syn pathology in the mechanisms leading to PD. However, the normal functions of α-syn still remain to be fully elucidated. Notably, α-syn in the hematopoietic system seems to mediate important functions as indicated by anemia and incomplete cell maturation when this protein is absent. This review will summarize basic genetic and structural findings, and critical information that suggests an essential role of α-syn in the development and activation of the hematopoietic system and immunity.
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Affiliation(s)
- Yu Pei
- University Hospitals Cleveland Medical Center, Cleveland, OH, United States
| | - Robert W. Maitta
- University Hospitals Cleveland Medical Center, Cleveland, OH, United States
- Case Western Reserve University School of Medicine, Cleveland, OH, United States
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24
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Chitirala P, Ravichandran K, Galgano D, Sleiman M, Krause E, Bryceson YT, Rettig J. Cytotoxic Granule Exocytosis From Human Cytotoxic T Lymphocytes Is Mediated by VAMP7. Front Immunol 2019; 10:1855. [PMID: 31447853 PMCID: PMC6692471 DOI: 10.3389/fimmu.2019.01855] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2019] [Accepted: 07/23/2019] [Indexed: 11/13/2022] Open
Abstract
Cytotoxic T lymphocytes kill infected or malignant cells through the directed release of cytotoxic substances at the site of target cell contact, the immunological synapse. While genetic association studies of genes predisposing to early-onset life-threatening hemophagocytic lymphohistiocytosis has identified components of the plasma membrane fusion machinery, the identity of the vesicular components remain enigmatic. Here, we identify VAMP7 as an essential component of the vesicular fusion machinery of primary, human T cells. VAMP7 co-localizes with granule markers throughout all stages of T cell maturation and simultaneously fuses with granule markers at the IS. Knock-down of VAMP7 expression significantly decreased the killing efficiency of T cells, without diminishing early T cell receptor signaling. VAMP7 exerts its function in a SNARE complex with Syntaxin11 and SNAP-23 on the plasma membrane. The identification of the minimal fusion machinery in T cells provides a starting point for the development of potential drugs in immunotherapy.
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Affiliation(s)
- Praneeth Chitirala
- Cellular Neurophysiology, Center for Integrative Physiology and Molecular Medicine (CIPMM), Saarland University, Homburg, Germany
| | - Keerthana Ravichandran
- Cellular Neurophysiology, Center for Integrative Physiology and Molecular Medicine (CIPMM), Saarland University, Homburg, Germany
| | - Donatella Galgano
- Center for Hematology and Regenerative Medicine (HERM), Karolinska Institute, Stockholm, Sweden
| | - Marwa Sleiman
- Cellular Neurophysiology, Center for Integrative Physiology and Molecular Medicine (CIPMM), Saarland University, Homburg, Germany
| | - Elmar Krause
- Cellular Neurophysiology, Center for Integrative Physiology and Molecular Medicine (CIPMM), Saarland University, Homburg, Germany
| | - Yenan T. Bryceson
- Center for Hematology and Regenerative Medicine (HERM), Karolinska Institute, Stockholm, Sweden
| | - Jens Rettig
- Cellular Neurophysiology, Center for Integrative Physiology and Molecular Medicine (CIPMM), Saarland University, Homburg, Germany
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25
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Hart M, Walch-Rückheim B, Krammes L, Kehl T, Rheinheimer S, Tänzer T, Glombitza B, Sester M, Lenhof HP, Keller A, Meese E. miR-34a as hub of T cell regulation networks. J Immunother Cancer 2019; 7:187. [PMID: 31311583 PMCID: PMC6636054 DOI: 10.1186/s40425-019-0670-5] [Citation(s) in RCA: 25] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2019] [Accepted: 07/08/2019] [Indexed: 12/27/2022] Open
Abstract
BACKGROUND Micro(mi)RNAs are increasingly recognized as central regulators of immune cell function. While it has been predicted that miRNAs have multiple targets, the majority of these predictions still await experimental confirmation. Here, miR-34a, a well-known tumor suppressor, is analyzed for targeting genes involved in immune system processes of leucocytes. METHODS Using an in-silico approach, we combined miRNA target prediction with GeneTrail2, a web tool for Multi-omics enrichment analysis, to identify miR-34a target genes, which are involved in the immune system process subcategory of Gene Ontology. RESULTS Out of the 193 predicted target genes in this subcategory we experimentally tested 22 target genes and confirmed binding of miR-34a to 14 target genes including VAMP2, IKBKE, MYH9, MARCH8, KLRK1, CD11A, TRAFD1, CCR1, PYDC1, PRF1, PIK3R2, PIK3CD, AP1B1, and ADAM10 by dual luciferase assays. By transfecting Jurkat, primary CD4+ and CD8+ T cells with miR-34a, we demonstrated that ectopic expression of miR-34a leads to reduced levels of endogenous VAMP2 and CD11A, which are central to the analyzed subcategories. Functional downstream analysis of miR-34a over-expression in activated CD8+ T cells exhibits a distinct decrease of PRF1 secretion. CONCLUSIONS By simultaneous targeting of 14 mRNAs miR-34a acts as major hub of T cell regulatory networks suggesting to utilize miR-34a as target of intervention towards a modulation of the immune responsiveness of T-cells in a broad tumor context.
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Affiliation(s)
- Martin Hart
- Institute of Human Genetics, Saarland University, Building 60, 66421, Homburg, Germany.
| | - Barbara Walch-Rückheim
- Institute of Virology and Center of Human and Molecular Biology, Saarland University, 66421, Homburg, Germany
| | - Lena Krammes
- Institute of Human Genetics, Saarland University, Building 60, 66421, Homburg, Germany
| | - Tim Kehl
- Center for Bioinformatics, Saarland University, 66123, Saarbrücken, Germany
| | - Stefanie Rheinheimer
- Institute of Human Genetics, Saarland University, Building 60, 66421, Homburg, Germany
| | - Tanja Tänzer
- Institute of Virology and Center of Human and Molecular Biology, Saarland University, 66421, Homburg, Germany
| | - Birgit Glombitza
- Institute of Virology and Center of Human and Molecular Biology, Saarland University, 66421, Homburg, Germany
| | - Martina Sester
- Department of Transplant and Infection Immunology, Saarland University, 66421, Homburg, Germany
| | - Hans-Peter Lenhof
- Center for Bioinformatics, Saarland University, 66123, Saarbrücken, Germany
| | - Andreas Keller
- Chair for Clinical Bioinformatics, Saarland University, 66123, Saarbrücken, Germany
| | - Eckart Meese
- Institute of Human Genetics, Saarland University, Building 60, 66421, Homburg, Germany
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26
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An Alternative Exon of CAPS2 Influences Catecholamine Loading into LDCVs of Chromaffin Cells. J Neurosci 2019; 39:18-27. [PMID: 30389842 DOI: 10.1523/jneurosci.2040-18.2018] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2018] [Revised: 10/01/2018] [Accepted: 10/27/2018] [Indexed: 11/21/2022] Open
Abstract
The calcium-dependent activator proteins for secretion (CAPS) are priming factors for synaptic and large dense-core vesicles (LDCVs), promoting their entry into and stabilizing the release-ready state. A modulatory role of CAPS in catecholamine loading of vesicles has been suggested. Although an influence of CAPS on monoamine transporter function and on vesicle acidification has been reported, a role of CAPS in vesicle loading is disputed. Using expression of naturally occurring splice variants of CAPS2 into chromaffin cells from CAPS1/CAPS2 double-deficient mice of both sexes, we show that an alternative exon of 40 aa is responsible for enhanced catecholamine loading of LDCVs in mouse chromaffin cells. The presence of this exon leads to increased activity of both vesicular monoamine transporters. Deletion of CAPS does not alter acidification of vesicles. Our results establish a splice-variant-dependent modulatory effect of CAPS on catecholamine content in LDCVs.SIGNIFICANCE STATEMENT The calcium activator protein for secretion (CAPS) promotes and stabilizes the entry of catecholamine-containing vesicles of the adrenal gland into a release-ready state. Expression of an alternatively spliced exon in CAPS leads to enhanced catecholamine content in chromaffin granules. This exon codes for 40 aa with a high proline content, consistent with an unstructured loop present in the portion of the molecule generally thought to be involved in vesicle priming. CAPS variants containing this exon promote serotonin uptake into Chinese hamster ovary cells expressing either vesicular monoamine transporter. Epigenetic tuning of CAPS variants may allow modulation of endocrine adrenaline and noradrenaline release. This mechanism may extend to monoamine release in central neurons or in the enteric nervous system.
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27
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Dingjan I, Linders PTA, Verboogen DRJ, Revelo NH, Ter Beest M, van den Bogaart G. Endosomal and Phagosomal SNAREs. Physiol Rev 2018; 98:1465-1492. [PMID: 29790818 DOI: 10.1152/physrev.00037.2017] [Citation(s) in RCA: 64] [Impact Index Per Article: 10.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022] Open
Abstract
The soluble N-ethylmaleimide-sensitive factor attachment protein receptor (SNARE) protein family is of vital importance for organelle communication. The complexing of cognate SNARE members present in both the donor and target organellar membranes drives the membrane fusion required for intracellular transport. In the endocytic route, SNARE proteins mediate trafficking between endosomes and phagosomes with other endosomes, lysosomes, the Golgi apparatus, the plasma membrane, and the endoplasmic reticulum. The goal of this review is to provide an overview of the SNAREs involved in endosomal and phagosomal trafficking. Of the 38 SNAREs present in humans, 30 have been identified at endosomes and/or phagosomes. Many of these SNAREs are targeted by viruses and intracellular pathogens, which thereby reroute intracellular transport for gaining access to nutrients, preventing their degradation, and avoiding their detection by the immune system. A fascinating picture is emerging of a complex transport network with multiple SNAREs being involved in consecutive trafficking routes.
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Affiliation(s)
- Ilse Dingjan
- Department of Tumor Immunology, Radboud Institute for Molecular Life Sciences, Radboud University Medical Center , Nijmegen , The Netherlands ; and Department of Molecular Immunology, Groningen Biomolecular Sciences and Biotechnology Institute, University of Groningen , Groningen , The Netherlands
| | - Peter T A Linders
- Department of Tumor Immunology, Radboud Institute for Molecular Life Sciences, Radboud University Medical Center , Nijmegen , The Netherlands ; and Department of Molecular Immunology, Groningen Biomolecular Sciences and Biotechnology Institute, University of Groningen , Groningen , The Netherlands
| | - Danielle R J Verboogen
- Department of Tumor Immunology, Radboud Institute for Molecular Life Sciences, Radboud University Medical Center , Nijmegen , The Netherlands ; and Department of Molecular Immunology, Groningen Biomolecular Sciences and Biotechnology Institute, University of Groningen , Groningen , The Netherlands
| | - Natalia H Revelo
- Department of Tumor Immunology, Radboud Institute for Molecular Life Sciences, Radboud University Medical Center , Nijmegen , The Netherlands ; and Department of Molecular Immunology, Groningen Biomolecular Sciences and Biotechnology Institute, University of Groningen , Groningen , The Netherlands
| | - Martin Ter Beest
- Department of Tumor Immunology, Radboud Institute for Molecular Life Sciences, Radboud University Medical Center , Nijmegen , The Netherlands ; and Department of Molecular Immunology, Groningen Biomolecular Sciences and Biotechnology Institute, University of Groningen , Groningen , The Netherlands
| | - Geert van den Bogaart
- Department of Tumor Immunology, Radboud Institute for Molecular Life Sciences, Radboud University Medical Center , Nijmegen , The Netherlands ; and Department of Molecular Immunology, Groningen Biomolecular Sciences and Biotechnology Institute, University of Groningen , Groningen , The Netherlands
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28
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Shaib AH, Staudt A, Harb A, Klose M, Shaaban A, Schirra C, Mohrmann R, Rettig J, Becherer U. Paralogs of the Calcium-Dependent Activator Protein for Secretion Differentially Regulate Synaptic Transmission and Peptide Secretion in Sensory Neurons. Front Cell Neurosci 2018; 12:304. [PMID: 30254567 PMCID: PMC6141663 DOI: 10.3389/fncel.2018.00304] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2018] [Accepted: 08/21/2018] [Indexed: 12/29/2022] Open
Abstract
The two paralogs of the calcium-dependent activator protein for secretion (CAPS) are priming factors for synaptic vesicles (SVs) and neuropeptide containing large dense-core vesicles (LDCVs). Yet, it is unclear whether CAPS1 and CAPS2 regulate exocytosis of these two vesicle types differentially in dorsal root ganglion (DRG) neurons, wherein synaptic transmission and neuropeptide release are of equal importance. These sensory neurons transfer information from the periphery to the spinal cord (SC), releasing glutamate as the primary neurotransmitter, with co-transmission via neuropeptides in a subset of so called peptidergic neurons. Neuropeptides are key components of the information-processing machinery of pain perception and neuropathic pain generation. Here, we compared the ability of CAPS1 and CAPS2 to support priming of both vesicle types in single and double knock-out mouse (DRG) neurons using a variety of high-resolution live cell imaging methods. While CAPS1 was localized to synapses of all DRG neurons and promoted synaptic transmission, CAPS2 was found exclusively in peptidergic neurons and mediated LDCV exocytosis. Intriguingly, ectopic expression of CAPS2 empowered non-peptidergic neurons to drive LDCV fusion, thereby identifying CAPS2 as an essential molecular determinant for peptidergic signaling. Our results reveal that these distinct functions of both CAPS paralogs are based on their differential subcellular localization in DRG neurons. Our data suggest a major role for CAPS2 in neuropathic pain via control of neuropeptide release.
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Affiliation(s)
- Ali H. Shaib
- Department of Cellular Neurophysiology, Center for Integrative Physiology and Molecular Medicine (CIPMM), Saarland University, Homburg, Germany
| | - Angelina Staudt
- Department of Cellular Neurophysiology, Center for Integrative Physiology and Molecular Medicine (CIPMM), Saarland University, Homburg, Germany
| | - Ali Harb
- Department of Cellular Neurophysiology, Center for Integrative Physiology and Molecular Medicine (CIPMM), Saarland University, Homburg, Germany
- ZHMB Junior Group, Center for Integrative Physiology and Molecular Medicine (CIPMM), Saarland University, Homburg, Germany
| | - Margarete Klose
- Department of Cellular Neurophysiology, Center for Integrative Physiology and Molecular Medicine (CIPMM), Saarland University, Homburg, Germany
| | - Ahmed Shaaban
- ZHMB Junior Group, Center for Integrative Physiology and Molecular Medicine (CIPMM), Saarland University, Homburg, Germany
| | - Claudia Schirra
- Department of Cellular Neurophysiology, Center for Integrative Physiology and Molecular Medicine (CIPMM), Saarland University, Homburg, Germany
| | - Ralf Mohrmann
- ZHMB Junior Group, Center for Integrative Physiology and Molecular Medicine (CIPMM), Saarland University, Homburg, Germany
| | - Jens Rettig
- Department of Cellular Neurophysiology, Center for Integrative Physiology and Molecular Medicine (CIPMM), Saarland University, Homburg, Germany
| | - Ute Becherer
- Department of Cellular Neurophysiology, Center for Integrative Physiology and Molecular Medicine (CIPMM), Saarland University, Homburg, Germany
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29
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Chang HF, Mannebach S, Beck A, Ravichandran K, Krause E, Frohnweiler K, Fecher-Trost C, Schirra C, Pattu V, Flockerzi V, Rettig J. Cytotoxic granule endocytosis depends on the Flower protein. J Cell Biol 2018; 217:667-683. [PMID: 29288152 PMCID: PMC5800809 DOI: 10.1083/jcb.201706053] [Citation(s) in RCA: 9] [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: 06/09/2017] [Revised: 11/09/2017] [Accepted: 11/29/2017] [Indexed: 12/23/2022] Open
Abstract
Cytotoxic T lymphocytes (CTLs) kill target cells by the regulated release of cytotoxic substances from granules at the immunological synapse. To kill multiple target cells, CTLs use endocytosis of membrane components of cytotoxic granules. We studied the potential calcium dependence of endocytosis in mouse CTLs on Flower, which mediates the calcium dependence of synaptic vesicle endocytosis in Drosophila melanogaster Flower is predominantly localized on intracellular vesicles that move to the synapse on target cell contact. Endocytosis is entirely blocked at an early stage in Flower-deficient CTLs and is rescued to wild-type level by reintroducing Flower or by raising extracellular calcium. A Flower mutant lacking binding sites for the endocytic adaptor AP-2 proteins fails to rescue endocytosis, indicating that Flower interacts with proteins of the endocytic machinery to mediate granule endocytosis. Thus, our data identify Flower as a key protein mediating granule endocytosis.
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Affiliation(s)
- Hsin-Fang Chang
- Cellular Neurophysiology, Center for Integrative Physiology and Molecular Medicine, Saarland University, Homburg, Germany
| | - Stefanie Mannebach
- Department of Experimental and Clinical Pharmacology and Toxicology and Preclinical Center for Molecular Signaling, Saarland University, Homburg, Germany
| | - Andreas Beck
- Department of Experimental and Clinical Pharmacology and Toxicology and Preclinical Center for Molecular Signaling, Saarland University, Homburg, Germany
- Center of Human and Molecular Biology, Saarland University, Homburg, Germany
| | - Keerthana Ravichandran
- Cellular Neurophysiology, Center for Integrative Physiology and Molecular Medicine, Saarland University, Homburg, Germany
| | - Elmar Krause
- Cellular Neurophysiology, Center for Integrative Physiology and Molecular Medicine, Saarland University, Homburg, Germany
| | - Katja Frohnweiler
- Department of Experimental and Clinical Pharmacology and Toxicology and Preclinical Center for Molecular Signaling, Saarland University, Homburg, Germany
| | - Claudia Fecher-Trost
- Department of Experimental and Clinical Pharmacology and Toxicology and Preclinical Center for Molecular Signaling, Saarland University, Homburg, Germany
| | - Claudia Schirra
- Cellular Neurophysiology, Center for Integrative Physiology and Molecular Medicine, Saarland University, Homburg, Germany
| | - Varsha Pattu
- Cellular Neurophysiology, Center for Integrative Physiology and Molecular Medicine, Saarland University, Homburg, Germany
| | - Veit Flockerzi
- Department of Experimental and Clinical Pharmacology and Toxicology and Preclinical Center for Molecular Signaling, Saarland University, Homburg, Germany
| | - Jens Rettig
- Cellular Neurophysiology, Center for Integrative Physiology and Molecular Medicine, Saarland University, Homburg, Germany
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30
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SM protein Munc18-2 facilitates transition of Syntaxin 11-mediated lipid mixing to complete fusion for T-lymphocyte cytotoxicity. Proc Natl Acad Sci U S A 2017; 114:E2176-E2185. [PMID: 28265073 DOI: 10.1073/pnas.1617981114] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
The atypical lipid-anchored Syntaxin 11 (STX11) and its binding partner, the Sec/Munc (SM) protein Munc18-2, facilitate cytolytic granule release by cytotoxic T lymphocytes (CTLs) and natural killer (NK) cells. Patients carrying mutations in these genes develop familial hemophagocytic lymphohistiocytosis, a primary immunodeficiency characterized by impaired lytic granule exocytosis. However, whether a SNARE such as STX11, which lacks a transmembrane domain, can support membrane fusion in vivo is uncertain, as is the precise role of Munc18-2 during lytic granule exocytosis. Here, using a reconstituted "flipped" cell-cell fusion assay, we show that lipid-anchored STX11 and its cognate SNARE proteins mainly support exchange of lipids but not cytoplasmic content between cells, resembling hemifusion. Strikingly, complete fusion is stimulated by addition of wild-type Munc18-2 to the assay, but not of Munc18-2 mutants with abnormal STX11 binding. Our data reveal that Munc18-2 is not just a chaperone of STX11 but also directly contributes to complete membrane merging by promoting SNARE complex assembly. These results further support the concept that SM proteins in general are part of the core fusion machinery. This fusion mechanism likely contributes to other cell-type-specific exocytic processes such as platelet secretion.
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31
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Obino D, Diaz J, Sáez JJ, Ibañez-Vega J, Sáez PJ, Alamo M, Lankar D, Yuseff MI. Vamp-7-dependent secretion at the immune synapse regulates antigen extraction and presentation in B-lymphocytes. Mol Biol Cell 2017; 28:890-897. [PMID: 28179460 PMCID: PMC5385938 DOI: 10.1091/mbc.e16-10-0722] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2016] [Revised: 01/31/2017] [Accepted: 02/01/2017] [Indexed: 11/11/2022] Open
Abstract
Recognition of surface-tethered antigens (Ags) by B-cells leads to the formation of an immune synapse that promotes Ag uptake for presentation onto MHC-II molecules. Extraction of immobilized Ags at the immune synapse of B-cells relies on the local secretion of lysosomes, which are recruited to the Ag contact site by polarization of their microtubule network. Although conserved polarity proteins have been implicated in coordinating cytoskeleton remodeling with lysosome trafficking, the cellular machinery associated with lysosomal vesicles that regulates their docking and secretion at the synaptic interface has not been defined. Here we show that the v-SNARE protein Vamp-7 is associated with Lamp-1+ lysosomal vesicles, which are recruited and docked at the center of the immune synapse of B-cells. A decrease in Vamp-7 expression does not alter lysosome transport to the synaptic interface but impairs their local secretion, a defect that compromises the ability of B-cells to extract, process, and present immobilized Ag. Thus our results reveal that B-cells rely on the SNARE protein Vamp-7 to promote the local exocytosis of lysosomes at the immune synapse, which is required for efficient Ag extraction and presentation.
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Affiliation(s)
- Dorian Obino
- INSERM, U932 Immunité et Cancer, Institut Curie, PSL Research University, 75005 Paris, France
| | - Jheimmy Diaz
- Department of Cellular and Molecular Biology, Faculty of Sciences, Pontificia Universidad Católica de Chile, Santiago 8331150, Chile
| | - Juan José Sáez
- Department of Cellular and Molecular Biology, Faculty of Sciences, Pontificia Universidad Católica de Chile, Santiago 8331150, Chile
| | - Jorge Ibañez-Vega
- Department of Cellular and Molecular Biology, Faculty of Sciences, Pontificia Universidad Católica de Chile, Santiago 8331150, Chile
| | - Pablo J Sáez
- INSERM, U932 Immunité et Cancer, Institut Curie, PSL Research University, 75005 Paris, France
| | - Martina Alamo
- Department of Cellular and Molecular Biology, Faculty of Sciences, Pontificia Universidad Católica de Chile, Santiago 8331150, Chile
| | - Danielle Lankar
- INSERM, U932 Immunité et Cancer, Institut Curie, PSL Research University, 75005 Paris, France
| | - Maria-Isabel Yuseff
- Department of Cellular and Molecular Biology, Faculty of Sciences, Pontificia Universidad Católica de Chile, Santiago 8331150, Chile
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32
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Chang HF, Bzeih H, Chitirala P, Ravichandran K, Sleiman M, Krause E, Hahn U, Pattu V, Rettig J. Preparing the lethal hit: interplay between exo- and endocytic pathways in cytotoxic T lymphocytes. Cell Mol Life Sci 2016; 74:399-408. [PMID: 27585956 PMCID: PMC5241346 DOI: 10.1007/s00018-016-2350-7] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2016] [Revised: 08/08/2016] [Accepted: 08/29/2016] [Indexed: 12/11/2022]
Abstract
Cytotoxic T lymphocytes patrol our body in search for infected cells which they kill through the release of cytotoxic substances contained in cytotoxic granules. The fusion of cytotoxic granules occurs at a specially formed contact site, the immunological synapse, and is tightly controlled to ensure specificity. In this review, we discuss the contribution of two intracellular compartments, endosomes and cytotoxic granules, to the formation, function and disassembly of the immunological synapse. We highlight a recently proposed sequential process of fusion events at the IS upon target cell recognition. First, recycling endosomes fuse with the plasma membrane to deliver cargo required for the docking of cytotoxic granules. Second, cytotoxic granules arrive and fuse upon docking in a SNARE-dependent manner. Following fusion, membrane components of the cytotoxic granule are retrieved through endocytosis to ensure the fast, efficient serial killing of target cells that is characteristic of cytotoxic T lymphocytes.
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Affiliation(s)
- Hsin-Fang Chang
- Cellular Neurophysiology, Center for Integrative Physiology and Molecular Medicine, Saarland University, 66421, Homburg, Germany
| | - Hawraa Bzeih
- Cellular Neurophysiology, Center for Integrative Physiology and Molecular Medicine, Saarland University, 66421, Homburg, Germany
| | - Praneeth Chitirala
- Cellular Neurophysiology, Center for Integrative Physiology and Molecular Medicine, Saarland University, 66421, Homburg, Germany
| | - Keerthana Ravichandran
- Cellular Neurophysiology, Center for Integrative Physiology and Molecular Medicine, Saarland University, 66421, Homburg, Germany
| | - Marwa Sleiman
- Cellular Neurophysiology, Center for Integrative Physiology and Molecular Medicine, Saarland University, 66421, Homburg, Germany
| | - Elmar Krause
- Cellular Neurophysiology, Center for Integrative Physiology and Molecular Medicine, Saarland University, 66421, Homburg, Germany
| | - Ulrike Hahn
- Cellular Neurophysiology, Center for Integrative Physiology and Molecular Medicine, Saarland University, 66421, Homburg, Germany
| | - Varsha Pattu
- Cellular Neurophysiology, Center for Integrative Physiology and Molecular Medicine, Saarland University, 66421, Homburg, Germany
| | - Jens Rettig
- Cellular Neurophysiology, Center for Integrative Physiology and Molecular Medicine, Saarland University, 66421, Homburg, Germany.
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33
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Chang HF, Bzeih H, Schirra C, Chitirala P, Halimani M, Cordat E, Krause E, Rettig J, Pattu V. Endocytosis of Cytotoxic Granules Is Essential for Multiple Killing of Target Cells by T Lymphocytes. THE JOURNAL OF IMMUNOLOGY 2016; 197:2473-84. [PMID: 27527597 DOI: 10.4049/jimmunol.1600828] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/10/2016] [Accepted: 07/20/2016] [Indexed: 11/19/2022]
Abstract
CTLs are serial killers that kill multiple target cells via exocytosis of cytotoxic granules (CGs). CG exocytosis is tightly regulated and has been investigated in great detail; however, whether CG proteins are endocytosed following exocytosis and contribute to serial killing remains unknown. By using primary CTLs derived from a knock-in mouse of the CG membrane protein Synaptobrevin2, we show that CGs are endocytosed in a clathrin- and dynamin-dependent manner. Following acidification, endocytosed CGs are recycled through early and late, but not recycling endosomes. CGs are refilled with granzyme B at the late endosome stage and polarize to subsequent synapses formed between the CTL and new target cells. Importantly, inhibiting CG endocytosis in CTLs results in a significant reduction of their cytotoxic activity. Thus, our data demonstrate that continuous endocytosis of CG membrane proteins is a prerequisite for efficient serial killing of CTLs and identify key events in this process.
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Affiliation(s)
- Hsin-Fang Chang
- Center for Integrative Physiology and Molecular Medicine, Saarland University, 66421 Homburg/Saar, Germany; and
| | - Hawraa Bzeih
- Center for Integrative Physiology and Molecular Medicine, Saarland University, 66421 Homburg/Saar, Germany; and
| | - Claudia Schirra
- Center for Integrative Physiology and Molecular Medicine, Saarland University, 66421 Homburg/Saar, Germany; and
| | - Praneeth Chitirala
- Center for Integrative Physiology and Molecular Medicine, Saarland University, 66421 Homburg/Saar, Germany; and
| | - Mahantappa Halimani
- Center for Integrative Physiology and Molecular Medicine, Saarland University, 66421 Homburg/Saar, Germany; and
| | - Emmanuelle Cordat
- Department of Physiology, University of Alberta, Edmonton T6G 2H7, Alberta, Canada
| | - Elmar Krause
- Center for Integrative Physiology and Molecular Medicine, Saarland University, 66421 Homburg/Saar, Germany; and
| | - Jens Rettig
- Center for Integrative Physiology and Molecular Medicine, Saarland University, 66421 Homburg/Saar, Germany; and
| | - Varsha Pattu
- Center for Integrative Physiology and Molecular Medicine, Saarland University, 66421 Homburg/Saar, Germany; and
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34
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Lou J, Rossy J, Deng Q, Pageon SV, Gaus K. New Insights into How Trafficking Regulates T Cell Receptor Signaling. Front Cell Dev Biol 2016; 4:77. [PMID: 27508206 PMCID: PMC4960267 DOI: 10.3389/fcell.2016.00077] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2016] [Accepted: 07/11/2016] [Indexed: 02/04/2023] Open
Abstract
There is emerging evidence that exocytosis plays an important role in regulating T cell receptor (TCR) signaling. The trafficking molecules involved in lytic granule (LG) secretion in cytotoxic T lymphocytes (CTL) have been well-studied due to the immune disorder known as familial hemophagocytic lymphohistiocytosis (FHLH). However, the knowledge of trafficking machineries regulating the exocytosis of receptors and signaling molecules remains quite limited. In this review, we summarize the reported trafficking molecules involved in the transport of the TCR and downstream signaling molecules to the cell surface. By combining this information with the known knowledge of LG exocytosis and general exocytic trafficking machinery, we attempt to draw a more complete picture of how the TCR signaling network and exocytic trafficking matrix are interconnected to facilitate T cell activation. This also highlights how membrane compartmentalization facilitates the spatiotemporal organization of cellular responses that are essential for immune functions.
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Affiliation(s)
- Jieqiong Lou
- EMBL Australia Node in Single Molecule Science, School of Medical Sciences, University of New South WalesSydney, NSW, Australia; ARC Centre of Excellence in Advanced Molecular Imaging, University of New South WalesSydney, NSW, Australia
| | - Jérémie Rossy
- EMBL Australia Node in Single Molecule Science, School of Medical Sciences, University of New South WalesSydney, NSW, Australia; ARC Centre of Excellence in Advanced Molecular Imaging, University of New South WalesSydney, NSW, Australia
| | - Qiji Deng
- EMBL Australia Node in Single Molecule Science, School of Medical Sciences, University of New South WalesSydney, NSW, Australia; ARC Centre of Excellence in Advanced Molecular Imaging, University of New South WalesSydney, NSW, Australia
| | - Sophie V Pageon
- EMBL Australia Node in Single Molecule Science, School of Medical Sciences, University of New South WalesSydney, NSW, Australia; ARC Centre of Excellence in Advanced Molecular Imaging, University of New South WalesSydney, NSW, Australia
| | - Katharina Gaus
- EMBL Australia Node in Single Molecule Science, School of Medical Sciences, University of New South WalesSydney, NSW, Australia; ARC Centre of Excellence in Advanced Molecular Imaging, University of New South WalesSydney, NSW, Australia
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35
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Dhara M, Yarzagaray A, Makke M, Schindeldecker B, Schwarz Y, Shaaban A, Sharma S, Böckmann RA, Lindau M, Mohrmann R, Bruns D. v-SNARE transmembrane domains function as catalysts for vesicle fusion. eLife 2016; 5:e17571. [PMID: 27343350 PMCID: PMC4972536 DOI: 10.7554/elife.17571] [Citation(s) in RCA: 41] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2016] [Accepted: 06/24/2016] [Indexed: 12/22/2022] Open
Abstract
Vesicle fusion is mediated by an assembly of SNARE proteins between opposing membranes, but it is unknown whether transmembrane domains (TMDs) of SNARE proteins serve mechanistic functions that go beyond passive anchoring of the force-generating SNAREpin to the fusing membranes. Here, we show that conformational flexibility of synaptobrevin-2 TMD is essential for efficient Ca(2+)-triggered exocytosis and actively promotes membrane fusion as well as fusion pore expansion. Specifically, the introduction of helix-stabilizing leucine residues within the TMD region spanning the vesicle's outer leaflet strongly impairs exocytosis and decelerates fusion pore dilation. In contrast, increasing the number of helix-destabilizing, ß-branched valine or isoleucine residues within the TMD restores normal secretion but accelerates fusion pore expansion beyond the rate found for the wildtype protein. These observations provide evidence that the synaptobrevin-2 TMD catalyzes the fusion process by its structural flexibility, actively setting the pace of fusion pore expansion.
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Affiliation(s)
- Madhurima Dhara
- Institute for Physiology, Saarland University, Homburg, Germany
| | | | - Mazen Makke
- Institute for Physiology, Saarland University, Homburg, Germany
| | | | - Yvonne Schwarz
- Institute for Physiology, Saarland University, Homburg, Germany
| | - Ahmed Shaaban
- Zentrum für Human- und Molekularbiologie, Saarland University, Homburg, Germany
| | - Satyan Sharma
- Group Nanoscale Cell Biology, Max-Planck-Institute for Biophysical Chemistry, Göttingen, Germany
| | - Rainer A Böckmann
- Computational Biology, Department of Biology, Friedrich-Alexander University, Erlangen, Germany
| | - Manfred Lindau
- Group Nanoscale Cell Biology, Max-Planck-Institute for Biophysical Chemistry, Göttingen, Germany
| | - Ralf Mohrmann
- Zentrum für Human- und Molekularbiologie, Saarland University, Homburg, Germany
| | - Dieter Bruns
- Institute for Physiology, Saarland University, Homburg, Germany
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36
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Thorn P, Zorec R, Rettig J, Keating DJ. Exocytosis in non-neuronal cells. J Neurochem 2016; 137:849-59. [PMID: 26938142 DOI: 10.1111/jnc.13602] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2015] [Revised: 02/02/2016] [Accepted: 03/01/2016] [Indexed: 12/18/2022]
Abstract
Exocytosis is the process by which stored neurotransmitters and hormones are released via the fusion of secretory vesicles with the plasma membrane. It is a dynamic, rapid and spatially restricted process involving multiple steps including vesicle trafficking, tethering, docking, priming and fusion. For many years great steps have been undertaken in our understanding of how exocytosis occurs in different cell types, with significant focus being placed on synaptic release and neurotransmission. However, this process of exocytosis is an essential component of cell signalling throughout the body and underpins a diverse array of essential physiological pathways. Many similarities exist between different cell types with regard to key aspects of the exocytosis pathway, such as the need for Ca(2+) to trigger it or the involvement of members of the N-ethyl maleimide-sensitive fusion protein attachment protein receptor protein families. However, it is also equally clear that non-neuronal cells have acquired highly specialized mechanisms to control the release of their own unique chemical messengers. This review will focus on several important non-neuronal cell types and discuss what we know about the mechanisms they use to control exocytosis and how their specialized output is relevant to the physiological role of each individual cell type. These include enteroendocrine cells, pancreatic β cells, astrocytes, lactotrophs and cytotoxic T lymphocytes. Non-neuronal cells have acquired highly specialized mechanisms to control the release of unique chemical messengers, such as polarised fusion of insulin granules in pancreatic β cells targeted towards the vasculature (top). This review discusses mechanisms used in several important non-neuronal cell types to control exocytosis, and the relevance of intermediate vesicle fusion pore states (bottom) and their specialized output to the physiological role of each cell type. These include enteroendocrine cells, pancreatic β cells, astrocytes, lactotrophs and cytotoxic T lymphocytes. This article is part of a mini review series on Chromaffin cells (ISCCB Meeting, 2015).
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Affiliation(s)
- Peter Thorn
- Charles Perkins Centre, John Hopkins Drive, The University of Sydney, Camperdown, NSW, Australia
| | - Robert Zorec
- Laboratory of Neuroendocrinology and Molecular Cell Physiology, Institute of Pathophysiology, University of Ljubljana, Faculty of Medicine, Ljubljana, Slovenia.,Celica Biomedical, Ljubljana, Slovenia
| | - Jens Rettig
- Cellular Neurophysiology, Center for Integrative Physiology and Molecular Medicine, Saarland University, Homburg, Germany
| | - Damien J Keating
- Department of Human Physiology and Centre for Neuroscience, Flinders University, Adelaide, SA, Australia.,South Australian Health and Medical Research Institute (SAHMRI), Adelaide, Australia
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37
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Bhat SS, Friedmann KS, Knörck A, Hoxha C, Leidinger P, Backes C, Meese E, Keller A, Rettig J, Hoth M, Qu B, Schwarz EC. Syntaxin 8 is required for efficient lytic granule trafficking in cytotoxic T lymphocytes. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2016; 1863:1653-64. [PMID: 27094127 DOI: 10.1016/j.bbamcr.2016.04.014] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/20/2015] [Revised: 03/23/2016] [Accepted: 04/14/2016] [Indexed: 12/21/2022]
Abstract
Cytotoxic T lymphocytes (CTL) eliminate pathogen-infected and cancerous cells mainly by polarized secretion of lytic granules (LG, containing cytotoxic molecules like perforin and granzymes) at the immunological synapse (IS). Members of the SNARE (soluble N-ethylmaleimide-sensitive factor attachment protein receptor) family are involved in trafficking (generation, transport and fusion) of vesicles at the IS. Syntaxin 8 (Stx8) is expressed in LG and colocalizes with the T cell receptor (TCR) upon IS formation. Here, we report the significance of Stx8 for human CTL cytotoxicity. We found that Stx8 mostly localized in late, recycling endosomal and lysosomal compartments with little expression in early endosomal compartments. Down-regulation of Stx8 by siRNA resulted in reduced cytotoxicity. We found that following perforin release of the pre-existing pool upon target cell contact, Stx8 down-regulated CTL regenerate perforin pools less efficiently and thus release less perforin compared to control CTL. CD107a degranulation, real-time and end-point population cytotoxicity assays, and high resolution microscopy support our conclusion that Stx8 is required for proper and timely sorting and trafficking of cytotoxic molecules to functional LG through the endosomal pathway in human CTL.
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Affiliation(s)
- Shruthi S Bhat
- Biophysics, Center for Integrative Physiology and Molecular Medicine, School of Medicine, Saarland University, Building 48, 66421 Homburg, Germany.
| | - Kim S Friedmann
- Biophysics, Center for Integrative Physiology and Molecular Medicine, School of Medicine, Saarland University, Building 48, 66421 Homburg, Germany.
| | - Arne Knörck
- Biophysics, Center for Integrative Physiology and Molecular Medicine, School of Medicine, Saarland University, Building 48, 66421 Homburg, Germany.
| | - Cora Hoxha
- Biophysics, Center for Integrative Physiology and Molecular Medicine, School of Medicine, Saarland University, Building 48, 66421 Homburg, Germany.
| | - Petra Leidinger
- Human Genetics, School of Medicine, Saarland University, Building 60, 66421 Homburg, Germany.
| | - Christina Backes
- Center for Bioinformatics, Saarland University, Building E2.1, 66123 Saarbrücken, Germany.
| | - Eckart Meese
- Human Genetics, School of Medicine, Saarland University, Building 60, 66421 Homburg, Germany.
| | - Andreas Keller
- Center for Bioinformatics, Saarland University, Building E2.1, 66123 Saarbrücken, Germany.
| | - Jens Rettig
- Physiology, Center for Integrative Physiology and Molecular Medicine, School of Medicine, Saarland University, Building 48, 66421 Homburg, Germany.
| | - Markus Hoth
- Biophysics, Center for Integrative Physiology and Molecular Medicine, School of Medicine, Saarland University, Building 48, 66421 Homburg, Germany.
| | - Bin Qu
- Biophysics, Center for Integrative Physiology and Molecular Medicine, School of Medicine, Saarland University, Building 48, 66421 Homburg, Germany.
| | - Eva C Schwarz
- Biophysics, Center for Integrative Physiology and Molecular Medicine, School of Medicine, Saarland University, Building 48, 66421 Homburg, Germany.
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38
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Chiaruttini G, Piperno GM, Jouve M, De Nardi F, Larghi P, Peden AA, Baj G, Müller S, Valitutti S, Galli T, Benvenuti F. The SNARE VAMP7 Regulates Exocytic Trafficking of Interleukin-12 in Dendritic Cells. Cell Rep 2016; 14:2624-36. [PMID: 26972013 PMCID: PMC4806224 DOI: 10.1016/j.celrep.2016.02.055] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2015] [Revised: 12/21/2015] [Accepted: 02/09/2016] [Indexed: 11/24/2022] Open
Abstract
Interleukin-12 (IL-12), produced by dendritic cells in response to activation, is central to pathogen eradication and tumor rejection. The trafficking pathways controlling spatial distribution and intracellular transport of IL-12 vesicles to the cell surface are still unknown. Here, we show that intracellular IL-12 localizes in late endocytic vesicles marked by the SNARE VAMP7. Dendritic cells (DCs) from VAMP7-deficient mice are partially impaired in the multidirectional release of IL-12. Upon encounter with antigen-specific T cells, IL-12-containing vesicles rapidly redistribute at the immune synapse and release IL-12 in a process entirely dependent on VAMP7 expression. Consistently, acquisition of effector functions is reduced in T cells stimulated by VAMP7-null DCs. These results provide insights into IL-12 intracellular trafficking pathways and show that VAMP7-mediated release of IL-12 at the immune synapse is a mechanism to transmit innate signals to T cells. Intracellular trafficking of IL-12 in dendritic cells is mediated by the SNARE VAMP7 VAMP7 is required for optimal secretion of IL-12 in the extracellular space IL-12/VAMP7+ vesicles gather at the immune synapse VAMP7 controls synaptic release of IL-12 and IFN-γ production in T cells
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Affiliation(s)
- Giulia Chiaruttini
- International Centre for Genetic Engineering and Biotechnology, Padriciano 99, 34149 Trieste, Italy
| | - Giulia M Piperno
- International Centre for Genetic Engineering and Biotechnology, Padriciano 99, 34149 Trieste, Italy
| | - Mabel Jouve
- Génétique et Biologie du Développement, UMR 3215, 26 rue d'Ulm, 75005 Paris, France
| | - Francesca De Nardi
- International Centre for Genetic Engineering and Biotechnology, Padriciano 99, 34149 Trieste, Italy
| | - Paola Larghi
- Department of Pathophysiology and Transplantation, University of Milan, via F. Sforza 35, 20122 Milan, Italy; Istituto Nazionale Genetica Molecolare "Romeo ed Enrica Invernizzi," via F. Sforza 35, 20122 Milan, Italy
| | - Andrew A Peden
- Centre for Membrane Interactions and Dynamics, Department of Biomedical Science, The University of Sheffield, Western Bank, Sheffield S10 2TN, UK
| | - Gabriele Baj
- Life Sciences Department, University of Trieste, via Giorgieri 5, 34127 Trieste, Italy
| | - Sabina Müller
- Centre de Physiopathologie Toulouse-Purpan, Toulouse, INSERM UMR 1043, Toulouse 31300, France
| | - Salvatore Valitutti
- Centre de Physiopathologie Toulouse-Purpan, Toulouse, INSERM UMR 1043, Toulouse 31300, France
| | - Thierry Galli
- Institut Jacques Monod, UMR 7592, Centre National de la Recherche Scientifique, Université Paris Diderot, Sorbonne Paris Cité, 75013 Paris, France; Membrane Traffic in Neuronal and Epithelial Morphogenesis, INSERM ERL U950, 75013 Paris, France
| | - Federica Benvenuti
- International Centre for Genetic Engineering and Biotechnology, Padriciano 99, 34149 Trieste, Italy.
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Ming M, Schirra C, Becherer U, Stevens DR, Rettig J. Behavior and Properties of Mature Lytic Granules at the Immunological Synapse of Human Cytotoxic T Lymphocytes. PLoS One 2015; 10:e0135994. [PMID: 26296096 PMCID: PMC4546685 DOI: 10.1371/journal.pone.0135994] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2015] [Accepted: 07/28/2015] [Indexed: 11/19/2022] Open
Abstract
Killing of virally infected cells or tumor cells by cytotoxic T lymphocytes requires targeting of lytic granules to the junction between the CTL and its target. We used whole-cell patch clamp to measure the cell capacitance at fixed intracellular [Ca2+] to study fusion of lytic granules in human CTLs. Expression of a fluorescently labeled human granzyme B construct allowed identification of lytic granule fusion using total internal reflection fluorescence microscopy. In this way capacitance steps due to lytic granule fusion were identified. Our goal was to determine the size of fusing lytic granules and to describe their behavior at the plasma membrane. On average, 5.02 ± 3.09 (mean ± s.d.) lytic granules were released per CTL. The amplitude of lytic granule fusion events was ~ 3.3 fF consistent with a diameter of about 325 nm. Fusion latency was biphasic with time constants of 15.9 and 106 seconds. The dwell time of fusing lytic granules was exponentially distributed with a mean dwell time of 28.5 seconds. Fusion ended in spite of the continued presence of granules at the immune synapse. The mobility of fusing granules at the membrane was indistinguishable from that of lytic granules which failed to fuse. While dwelling at the plasma membrane lytic granules exhibit mobility consistent with docking interspersed with short periods of greater mobility. The failure of lytic granules to fuse when visible in TIRF at the membrane may indicate that a membrane-confined reaction is rate limiting.
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Affiliation(s)
- Min Ming
- Center for Integrative Physiology and Molecular Medicine (CIPMM), Medical Faculty, Saarland University, 66421, Homburg, Germany
| | - Claudia Schirra
- Center for Integrative Physiology and Molecular Medicine (CIPMM), Medical Faculty, Saarland University, 66421, Homburg, Germany
| | - Ute Becherer
- Center for Integrative Physiology and Molecular Medicine (CIPMM), Medical Faculty, Saarland University, 66421, Homburg, Germany
| | - David R. Stevens
- Center for Integrative Physiology and Molecular Medicine (CIPMM), Medical Faculty, Saarland University, 66421, Homburg, Germany
| | - Jens Rettig
- Center for Integrative Physiology and Molecular Medicine (CIPMM), Medical Faculty, Saarland University, 66421, Homburg, Germany
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40
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Marshall MR, Pattu V, Halimani M, Maier-Peuschel M, Müller ML, Becherer U, Hong W, Hoth M, Tschernig T, Bryceson YT, Rettig J. VAMP8-dependent fusion of recycling endosomes with the plasma membrane facilitates T lymphocyte cytotoxicity. J Cell Biol 2015; 210:135-51. [PMID: 26124288 PMCID: PMC4493996 DOI: 10.1083/jcb.201411093] [Citation(s) in RCA: 60] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2014] [Accepted: 05/22/2015] [Indexed: 12/23/2022] Open
Abstract
VAMP8 is associated with the recycling endosome compartment rather than with cytotoxic granules and is required for a fusion step between recycling endosomes and the plasma membrane that brings syntaxin-11 to the immune synapse for cytotoxic granule exocytosis. Cytotoxic T lymphocytes (CTLs) eliminate infected and neoplastic cells through directed release of cytotoxic granule contents. Although multiple SNARE proteins have been implicated in cytotoxic granule exocytosis, the role of vesicular SNARE proteins, i.e., vesicle-associated membrane proteins (VAMPs), remains enigmatic. VAMP8 was posited to represent the cytotoxic granule vesicular SNARE protein mediating exocytosis in mice. In primary human CTLs, however, VAMP8 colocalized with Rab11a-positive recycling endosomes. Upon stimulation, these endosomes rapidly trafficked to and fused with the plasma membrane, preceding fusion of cytotoxic granules. Knockdown of VAMP8 blocked both recycling endosome and cytotoxic granule fusion at immune synapses, without affecting activating signaling. Mechanistically, VAMP8-dependent recycling endosomes deposited syntaxin-11 at immune synapses, facilitating assembly of plasma membrane SNARE complexes for cytotoxic granule fusion. Hence, cytotoxic granule exocytosis is a sequential, multivesicle fusion process requiring VAMP8-mediated recycling endosome fusion before cytotoxic granule fusion. Our findings imply that secretory granule exocytosis pathways in other cell types may also be more complex than previously appreciated.
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Affiliation(s)
- Misty R Marshall
- Cellular Neurophysiology, Center for Integrative Physiology and Molecular Medicine, Saarland University, 66421 Homburg, Germany Department of Medicine, Center For Infectious Medicine, 14186 Stockholm, Sweden
| | - Varsha Pattu
- Cellular Neurophysiology, Center for Integrative Physiology and Molecular Medicine, Saarland University, 66421 Homburg, Germany
| | - Mahantappa Halimani
- Cellular Neurophysiology, Center for Integrative Physiology and Molecular Medicine, Saarland University, 66421 Homburg, Germany Department of Pathology, Brigham and Woman's Hospital, Boston, MA
| | - Monika Maier-Peuschel
- Cellular Neurophysiology, Center for Integrative Physiology and Molecular Medicine, Saarland University, 66421 Homburg, Germany
| | - Martha-Lena Müller
- Department of Medicine, Center For Infectious Medicine, 14186 Stockholm, Sweden
| | - Ute Becherer
- Cellular Neurophysiology, Center for Integrative Physiology and Molecular Medicine, Saarland University, 66421 Homburg, Germany
| | - Wanjin Hong
- Membrane Biology Laboratory, Institute of Molecular and Cell Biology, Singapore 138673
| | - Markus Hoth
- Department of Biophysics, Saarland University, 66421 Homburg, Germany
| | - Thomas Tschernig
- Department of Anatomy, Saarland University, 66421 Homburg, Germany
| | - Yenan T Bryceson
- Department of Medicine, Center For Infectious Medicine, 14186 Stockholm, Sweden
| | - Jens Rettig
- Cellular Neurophysiology, Center for Integrative Physiology and Molecular Medicine, Saarland University, 66421 Homburg, Germany
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41
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Tang BL. The Cell Biology of Systemic Hyperinflammation Resulting from Failed Cytolytic Target Cell Killing. Cell 2015. [DOI: 10.4236/cellbio.2015.43005] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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42
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Organization of organelles and VAMP-associated vesicular transport systems in differentiating skeletal muscle cells. Anat Sci Int 2014; 90:33-9. [DOI: 10.1007/s12565-014-0266-6] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2014] [Accepted: 11/19/2014] [Indexed: 10/24/2022]
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43
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Pathophysiology and spectrum of diseases caused by defects in lymphocyte cytotoxicity. Exp Cell Res 2014; 325:10-7. [DOI: 10.1016/j.yexcr.2014.03.014] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2014] [Revised: 03/13/2014] [Accepted: 03/17/2014] [Indexed: 01/09/2023]
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44
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Halimani M, Pattu V, Marshall MR, Chang HF, Matti U, Jung M, Becherer U, Krause E, Hoth M, Schwarz EC, Rettig J. Syntaxin11 serves as a t‐
SNARE
for the fusion of lytic granules in human cytotoxic
T
lymphocytes. Eur J Immunol 2013; 44:573-84. [DOI: 10.1002/eji.201344011] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2013] [Revised: 10/07/2013] [Accepted: 11/06/2013] [Indexed: 11/11/2022]
Affiliation(s)
| | - Varsha Pattu
- Institut für PhysiologieUniversität des Saarlandes Homburg/Saar Germany
| | - Misty R. Marshall
- Institut für PhysiologieUniversität des Saarlandes Homburg/Saar Germany
| | - Hsin Fang Chang
- Institut für PhysiologieUniversität des Saarlandes Homburg/Saar Germany
| | - Ulf Matti
- Institut für PhysiologieUniversität des Saarlandes Homburg/Saar Germany
| | - Martin Jung
- Institut für BiochemieUniversität des Saarlandes Homburg/Saar Germany
| | - Ute Becherer
- Institut für PhysiologieUniversität des Saarlandes Homburg/Saar Germany
| | - Elmar Krause
- Institut für PhysiologieUniversität des Saarlandes Homburg/Saar Germany
| | - Markus Hoth
- Institut für BiophysikUniversität des Saarlandes Homburg/Saar Germany
| | - Eva C. Schwarz
- Institut für BiophysikUniversität des Saarlandes Homburg/Saar Germany
| | - Jens Rettig
- Institut für PhysiologieUniversität des Saarlandes Homburg/Saar Germany
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45
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Pattu V, Halimani M, Ming M, Schirra C, Hahn U, Bzeih H, Chang HF, Weins L, Krause E, Rettig J. In the crosshairs: investigating lytic granules by high-resolution microscopy and electrophysiology. Front Immunol 2013; 4:411. [PMID: 24348478 PMCID: PMC3841761 DOI: 10.3389/fimmu.2013.00411] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2013] [Accepted: 11/11/2013] [Indexed: 12/17/2022] Open
Abstract
Cytotoxic T lymphocytes (CTLs) form an integral part of the adaptive immune system. Their main function is to eliminate bacteria- and virus-infected target cells by releasing perforin and granzymes (the lethal hit) contained within lytic granules (LGs), at the CTL-target-cell interface [the immunological synapse (IS)]. The formation of the IS as well as the final events at the IS leading to target-cell death are both highly complex and dynamic processes. In this review we highlight and discuss three high-resolution techniques that have proven invaluable in the effort to decipher key features of the mechanism of CTL effector function and in particular lytic granule maturation and fusion. Correlative light and electron microscopy allows the correlation between organelle morphology and localization of particular proteins, while total internal reflection fluorescence microscopy (TIRFM) enables the study of lytic granule dynamics at the IS in real time. The combination of TIRFM with patch-clamp membrane capacitance measurements finally provides a tool to quantify the size of fusing LGs at the IS.
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Affiliation(s)
- Varsha Pattu
- Institute of Physiology, Saarland University , Homburg, Saar , Germany
| | | | - Min Ming
- Institute of Physiology, Saarland University , Homburg, Saar , Germany
| | - Claudia Schirra
- Institute of Physiology, Saarland University , Homburg, Saar , Germany
| | - Ulrike Hahn
- Institute of Physiology, Saarland University , Homburg, Saar , Germany
| | - Hawraa Bzeih
- Institute of Physiology, Saarland University , Homburg, Saar , Germany
| | - Hsin-Fang Chang
- Institute of Physiology, Saarland University , Homburg, Saar , Germany
| | - Lisa Weins
- Institute of Physiology, Saarland University , Homburg, Saar , Germany
| | - Elmar Krause
- Institute of Physiology, Saarland University , Homburg, Saar , Germany
| | - Jens Rettig
- Institute of Physiology, Saarland University , Homburg, Saar , Germany
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46
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Bost A, Pasche M, Schirra C, Becherer U. Super-resolution microscopy in studying neuroendocrine cell function. Front Neurosci 2013; 7:222. [PMID: 24324394 PMCID: PMC3839409 DOI: 10.3389/fnins.2013.00222] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2013] [Accepted: 11/04/2013] [Indexed: 12/13/2022] Open
Abstract
The last two decades have seen a tremendous development in high resolution microscopy techniques giving rise to acronyms such as TIRFM, SIM, PALM, STORM, and STED. The goal of all these techniques is to overcome the physical resolution barrier of light microscopy in order to resolve precise protein localization and possibly their interaction in cells. Neuroendocrine cell function is to secrete hormones and peptides on demand. This fine-tuned multi-step process is mediated by a large array of proteins. Here, we review the new microscopy techniques used to obtain high resolution and how they have been applied to increase our knowledge of the molecular mechanisms involved in neuroendocrine cell secretion. Further the limitations of these methods are discussed and insights in possible new applications are provided.
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Affiliation(s)
- Anneka Bost
- Physiologisches Institut, Universität des Saarlandes Homburg/Saar, Germany
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47
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van der Sluijs P, Zibouche M, van Kerkhof P. Late steps in secretory lysosome exocytosis in cytotoxic lymphocytes. Front Immunol 2013; 4:359. [PMID: 24302923 PMCID: PMC3831147 DOI: 10.3389/fimmu.2013.00359] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2013] [Accepted: 10/22/2013] [Indexed: 12/16/2022] Open
Abstract
Natural Killer cells are a subset of cytotoxic lymphocytes that are important in host defense against infections and transformed cells. They exert this function through recognition of target cells by cell surface receptors, which triggers a signaling program that results in a re-orientation of the microtubule organizing center and secretory lysosomes toward the target cell. Upon movement of secretory lysosomes to the plasma membrane and subsequent fusion, toxic proteins are released by secretory lysosomes in the immunological synapse which then enter and kill the target cell. In this minireview we highlight recent progress in our knowledge of late steps in this specialized secretion pathway and address important open questions.
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Affiliation(s)
- Peter van der Sluijs
- Department of Cell Biology, University Medical Center Utrecht , Utrecht , Netherlands
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Martín-Cófreces NB, Baixauli F, Sánchez-Madrid F. Immune synapse: conductor of orchestrated organelle movement. Trends Cell Biol 2013; 24:61-72. [PMID: 24119664 DOI: 10.1016/j.tcb.2013.09.005] [Citation(s) in RCA: 79] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2013] [Revised: 09/06/2013] [Accepted: 09/09/2013] [Indexed: 02/07/2023]
Abstract
To ensure proper cell function, intracellular organelles are not randomly distributed within the cell, but polarized and highly constrained by the cytoskeleton and associated adaptor proteins. This relationship between distribution and function was originally found in neurons and epithelial cells; however, recent evidence suggests that it is a general phenomenon occurring in many highly specialized cells including T lymphocytes. Recent studies reveal that the orchestrated redistribution of organelles is dependent on antigen-specific activation of and immune synapse (IS) formation by T cells. This review highlights the functional implications of organelle polarization in early T cell activation and examines recent findings on how the IS sets the rhythm of organelle motion and the spread of the activation signal to the nucleus.
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Affiliation(s)
- Noa Beatriz Martín-Cófreces
- Servicio de Inmunología, Hospital Universitario de la Princesa, UAM, IIS-IP, Madrid, Spain; Department of Vascular Biology and Inflammation, Fundación Centro Nacional de Investigaciones Cardiovasculares-Carlos III, Madrid, Spain
| | - Francesc Baixauli
- Servicio de Inmunología, Hospital Universitario de la Princesa, UAM, IIS-IP, Madrid, Spain; Department of Vascular Biology and Inflammation, Fundación Centro Nacional de Investigaciones Cardiovasculares-Carlos III, Madrid, Spain
| | - Francisco Sánchez-Madrid
- Servicio de Inmunología, Hospital Universitario de la Princesa, UAM, IIS-IP, Madrid, Spain; Department of Vascular Biology and Inflammation, Fundación Centro Nacional de Investigaciones Cardiovasculares-Carlos III, Madrid, Spain.
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