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Rytter H, Roger K, Chhuon C, Ding X, Coureuil M, Jamet A, Henry T, Guerrera IC, Charbit A. Dual proteomics of infected macrophages reveal bacterial and host players involved in the Francisella intracellular life cycle and cell to cell dissemination by merocytophagy. Sci Rep 2024; 14:7797. [PMID: 38565565 PMCID: PMC10987565 DOI: 10.1038/s41598-024-58261-x] [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: 01/09/2024] [Accepted: 03/27/2024] [Indexed: 04/04/2024] Open
Abstract
Bacterial pathogens adapt and replicate within host cells, while host cells develop mechanisms to eliminate them. Using a dual proteomic approach, we characterized the intra-macrophage proteome of the facultative intracellular pathogen, Francisella novicida. More than 900 Francisella proteins were identified in infected macrophages after a 10-h infection. Biotin biosynthesis-related proteins were upregulated, emphasizing the role of biotin-associated genes in Francisella replication. Conversely, proteins encoded by the Francisella pathogenicity island (FPI) were downregulated, supporting the importance of the F. tularensis Type VI Secretion System for vacuole escape, not cytosolic replication. In the host cell, over 300 proteins showed differential expression among the 6200 identified during infection. The most upregulated host protein was cis-aconitate decarboxylase IRG1, known for itaconate production with antimicrobial properties in Francisella. Surprisingly, disrupting IRG1 expression did not impact Francisella's intracellular life cycle, suggesting redundancy with other immune proteins or inclusion in larger complexes. Over-representation analysis highlighted cell-cell contact and actin polymerization in macrophage deregulated proteins. Using flow cytometry and live cell imaging, we demonstrated that merocytophagy involves diverse cell-to-cell contacts and actin polymerization-dependent processes. These findings lay the groundwork for further exploration of merocytophagy and its molecular mechanisms in future research.Data are available via ProteomeXchange with identifier PXD035145.
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Affiliation(s)
- Héloïse Rytter
- Université Paris CitéINSERM UMR-S1151, CNRS UMR-S8253Institut Necker Enfants Malades, 156-160 rue de Vaugirard, 75015, Paris, France
- INSERM U1151-CNRS UMR 8253, Team 7: Pathogénie des Infections Systémiques, 75015, Paris, France
| | - Kevin Roger
- INSERM US24/CNRS UAR3633, Proteomic Platform Necker, UniversitéParis-Cité, Federative Research Structure Necker, Paris, France
| | - Cerina Chhuon
- INSERM US24/CNRS UAR3633, Proteomic Platform Necker, UniversitéParis-Cité, Federative Research Structure Necker, Paris, France
| | - Xiongqi Ding
- Université Paris CitéINSERM UMR-S1151, CNRS UMR-S8253Institut Necker Enfants Malades, 156-160 rue de Vaugirard, 75015, Paris, France
- INSERM U1151-CNRS UMR 8253, Team 7: Pathogénie des Infections Systémiques, 75015, Paris, France
| | - Mathieu Coureuil
- Université Paris CitéINSERM UMR-S1151, CNRS UMR-S8253Institut Necker Enfants Malades, 156-160 rue de Vaugirard, 75015, Paris, France
- INSERM U1151-CNRS UMR 8253, Team 7: Pathogénie des Infections Systémiques, 75015, Paris, France
| | - Anne Jamet
- Université Paris CitéINSERM UMR-S1151, CNRS UMR-S8253Institut Necker Enfants Malades, 156-160 rue de Vaugirard, 75015, Paris, France
- INSERM U1151-CNRS UMR 8253, Team 7: Pathogénie des Infections Systémiques, 75015, Paris, France
| | - Thomas Henry
- CIRI, Centre International de Recherche en Infectiologie, Université Lyon, Inserm, U1111, Université Claude Bernard Lyon 1, CNRS, UMR5308, Ecole Normale Supérieure de Lyon, 69007, Lyon, France
| | - Ida Chiara Guerrera
- INSERM US24/CNRS UAR3633, Proteomic Platform Necker, UniversitéParis-Cité, Federative Research Structure Necker, Paris, France.
| | - Alain Charbit
- Université Paris CitéINSERM UMR-S1151, CNRS UMR-S8253Institut Necker Enfants Malades, 156-160 rue de Vaugirard, 75015, Paris, France.
- INSERM U1151-CNRS UMR 8253, Team 7: Pathogénie des Infections Systémiques, 75015, Paris, France.
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2
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Najera J, Berry MM, Ramirez AD, Reyes BR, Angel A, Jellyman JK, Mercer F. Bovine neutrophils kill the sexually-transmitted parasite Tritrichomonas foetus using trogocytosis. Vet Res Commun 2024; 48:865-875. [PMID: 37968413 PMCID: PMC10998815 DOI: 10.1007/s11259-023-10260-5] [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: 08/26/2023] [Accepted: 11/08/2023] [Indexed: 11/17/2023]
Abstract
The protozoan parasite Tritrichomonas foetus (T. foetus) is the causative organism of bovine trichomonosis (also referred to as trichomoniasis), a sexually-transmitted infection that reduces fertility in cattle. Efforts to control trichomonosis on cattle farms are hindered by the discouragement of antibiotic use in agriculture, and the incomplete, short-lived protection conferred by the current vaccines. A more complete mechanistic understanding of what effective immunity to T. foetus entails could enable the development of more robust infection control strategies. While neutrophils, the primary responders to infection, are present in infected tissues and have been shown to kill the parasite in vitro, the mechanism they use for parasite killing has not been established. Here, we show that primary bovine neutrophils isolated from peripheral blood rapidly kill T. foetus in vitro in a dose-dependent manner, and that optimal parasite killing is reduced by inhibitors of trogocytosis. We also use imaging to show that bovine neutrophils surround T. foetus and trogocytose its membrane. These findings are consistent with killing via trogocytosis, a recently described novel neutrophil antimicrobial mechanism.
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Affiliation(s)
- Jonathan Najera
- Department of Biological Sciences, California State Polytechnic University Pomona, Pomona, CA, 91768, USA
| | - Michael M Berry
- Department of Biological Sciences, California State Polytechnic University Pomona, Pomona, CA, 91768, USA
| | - Ashley D Ramirez
- Department of Biological Sciences, California State Polytechnic University Pomona, Pomona, CA, 91768, USA
| | - Bryan Ramirez Reyes
- Department of Biological Sciences, California State Polytechnic University Pomona, Pomona, CA, 91768, USA
| | - Arielle Angel
- Department of Biological Sciences, California State Polytechnic University Pomona, Pomona, CA, 91768, USA
| | - Juanita K Jellyman
- Department of Biological Sciences, California State Polytechnic University Pomona, Pomona, CA, 91768, USA
| | - Frances Mercer
- Department of Biological Sciences, California State Polytechnic University Pomona, Pomona, CA, 91768, USA.
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3
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Degabriel M, Valeva S, Boisset S, Henry T. Pathogenicity and virulence of Francisella tularensis. Virulence 2023; 14:2274638. [PMID: 37941380 PMCID: PMC10653695 DOI: 10.1080/21505594.2023.2274638] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2023] [Accepted: 10/18/2023] [Indexed: 11/10/2023] Open
Abstract
Tularaemia is a zoonotic disease caused by the Gram-negative bacterium, Francisella tularensis. Depending on its entry route into the organism, F. tularensis causes different diseases, ranging from life-threatening pneumonia to less severe ulceroglandular tularaemia. Various strains with different geographical distributions exhibit different levels of virulence. F. tularensis is an intracellular bacterium that replicates primarily in the cytosol of the phagocytes. The main virulence attribute of F. tularensis is the type 6 secretion system (T6SS) and its effectors that promote escape from the phagosome. In addition, F. tularensis has evolved a peculiar envelope that allows it to escape detection by the immune system. In this review, we cover tularaemia, different Francisella strains, and their pathogenicity. We particularly emphasize the intracellular life cycle, associated virulence factors, and metabolic adaptations. Finally, we present how F. tularensis largely escapes immune detection to be one of the most infectious and lethal bacterial pathogens.
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Affiliation(s)
- Manon Degabriel
- CIRI, Centre International de Recherche en Infectiologie, Inserm U1111, Université Claude Bernard Lyon 1, CNRS, UMR5308, ENS de Lyon, Univ Lyon, LYON, France
| | - Stanimira Valeva
- CIRI, Centre International de Recherche en Infectiologie, Inserm U1111, Université Claude Bernard Lyon 1, CNRS, UMR5308, ENS de Lyon, Univ Lyon, LYON, France
| | - Sandrine Boisset
- CIRI, Centre International de Recherche en Infectiologie, Inserm U1111, Université Claude Bernard Lyon 1, CNRS, UMR5308, ENS de Lyon, Univ Lyon, LYON, France
- Univ. Grenoble Alpes, CHU Grenoble Alpes, CNRS, CEA, UMR5075, Institut de Biologie Structurale, Grenoble, France
| | - Thomas Henry
- CIRI, Centre International de Recherche en Infectiologie, Inserm U1111, Université Claude Bernard Lyon 1, CNRS, UMR5308, ENS de Lyon, Univ Lyon, LYON, France
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4
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Wu J, Cai J, Tang Y, Lu B. The noncanonical inflammasome-induced pyroptosis and septic shock. Semin Immunol 2023; 70:101844. [PMID: 37778179 DOI: 10.1016/j.smim.2023.101844] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/01/2023] [Revised: 09/10/2023] [Accepted: 09/22/2023] [Indexed: 10/03/2023]
Abstract
Sepsis remains one of the most common and lethal conditions globally. Currently, no proposed target specific to sepsis improves survival in clinical trials. Thus, an in-depth understanding of the pathogenesis of sepsis is needed to propel the discovery of effective treatment. Recently attention to sepsis has intensified because of a growing recognition of a non-canonical inflammasome-triggered lytic mode of cell death termed pyroptosis upon sensing cytosolic lipopolysaccharide (LPS). Although the consequences of activation of the canonical and non-canonical inflammasome are similar, the non-canonical inflammasome formation requires caspase-4/5/11, which enzymatically cleave the pore-forming protein gasdermin D (GSDMD) and thereby cause pyroptosis. The non-canonical inflammasome assembly triggers such inflammatory cell death by itself; or leverages a secondary activation of the canonical NLRP3 inflammasome pathway. Excessive cell death induced by oligomerization of GSDMD and NINJ1 leads to cytokine release and massive tissue damage, facilitating devastating consequences and death. This review summarized the updated mechanisms that initiate and regulate non-canonical inflammasome activation and pyroptosis and highlighted various endogenous or synthetic molecules as potential therapeutic targets for treating sepsis.
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Affiliation(s)
- Junru Wu
- Department of Cardiology, The 3rd Xiangya Hospital, Central South University, Changsha 410000, PR China
| | - Jingjing Cai
- Department of Cardiology, The 3rd Xiangya Hospital, Central South University, Changsha 410000, PR China
| | - Yiting Tang
- Department of Physiology, School of Basic Medical Science, Central South University, Changsha 410000, PR China
| | - Ben Lu
- Department of Critical Care Medicine and Hematology, The 3rd Xiangya Hospital, Central South University, Changsha 410000, PR China; Key Laboratory of Sepsis Translational Medicine of Hunan, Central South University, Changsha 410000, PR China.
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5
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Alqahtani M, Ma Z, Miller J, Yu J, Malik M, Bakshi CS. Comparative analysis of absent in melanoma 2-inflammasome activation in Francisella tularensis and Francisella novicida. Front Microbiol 2023; 14:1188112. [PMID: 37266012 PMCID: PMC10230036 DOI: 10.3389/fmicb.2023.1188112] [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: 03/17/2023] [Accepted: 05/02/2023] [Indexed: 06/03/2023] Open
Abstract
Francisella tularensis is a highly virulent Gram-negative bacterium that causes the fatal zoonotic disease tularemia. The mechanisms and signaling pathways leading to the absent in melanoma 2 (Aim2) inflammasome activation have been elegantly elucidated using Francisella novicida as a model. Although not pathogenic for humans, F. novicida can cause tularemia in mice, and the inflammatory response it triggers is the polar opposite to that observed in mice infected with F. tularensis strains. This study aimed to understand the mechanisms of Aim2 inflammasome activation in F. tularensis-infected macrophages. The results reveal that macrophages infected with the F. tularensis live vaccine strain (LVS) induce lower levels of Aim2-dependent IL-1β than those infected with F. novicida. The suppression/weak activation of Aim2 in F. tularensis LVS-infected macrophages is due to the suppression of the cGAS-STING DNA-sensing pathway. Furthermore, the introduction of exogenous F. tularensis LVS DNA into the cytosol of the F. tularensis LVS-infected macrophages, alone or in conjunction with a priming signal, failed to restore IL-1β levels similar to those observed for F. novicida-infected macrophages. These results indicated that, in addition to the bacterial DNA, DNA from some other sources, specifically from the damaged mitochondria, might contribute to the robust Aim2-dependent IL-1β levels observed in F. novicida-infected macrophages. The results indicate that F. tularensis LVS induces mitophagy that may potentially prevent the leakage of mitochondrial DNA and the subsequent activation of the Aim2 inflammasome. Collectively, this study demonstrates that the mechanisms of Aim2 inflammasome activation established for F. novicida are not operative in F. tularensis.
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Affiliation(s)
- Maha Alqahtani
- Department of Pathology, Microbiology and Immunology, New York Medical College, Valhalla, NY, United States
| | - Zhuo Ma
- Department of Basic and Clinical Sciences, Albany College of Pharmacy and Health Sciences, Albany, NY, United States
| | - Jacob Miller
- Department of Basic and Clinical Sciences, Albany College of Pharmacy and Health Sciences, Albany, NY, United States
| | - Jen Yu
- Electron Microscopy Laboratory, Department of Pathology, Westchester Medical Center, Valhalla, NY, United States
| | - Meenakshi Malik
- Department of Basic and Clinical Sciences, Albany College of Pharmacy and Health Sciences, Albany, NY, United States
| | - Chandra Shekhar Bakshi
- Department of Pathology, Microbiology and Immunology, New York Medical College, Valhalla, NY, United States
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6
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Dominguez SR, Whiles S, Deobald KN, Kawula T. Francisella tularensis Exploits AMPK Activation to Harvest Host-Derived Nutrients Liberated from Host Lipolysis. Infect Immun 2022; 90:e0015522. [PMID: 35916521 PMCID: PMC9387300 DOI: 10.1128/iai.00155-22] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2022] [Accepted: 07/08/2022] [Indexed: 11/21/2022] Open
Abstract
Francisella tularensis is a zoonotic, facultative intracellular bacterial pathogen that replicates in a variety of cell types during infection. Following entry into the cell and phagosome escape, the bacterium replicates rapidly in the cytoplasm. F. tularensis intracellular growth depends on the availability of metabolizable essential nutrients to support replication. However, the mechanism by which metabolizable nutrients become available to the bacterium in the intracellular environment is not fully understood. We found that F. tularensis-infected cells had significantly smaller and fewer lipid droplets than uninfected cells. Inhibition of triacylglycerol degradation significantly reduced bacterial growth, whereas inhibition of triacylglycerol formation did not reduce bacterial growth, suggesting that triacylglycerols sequestered within lipid droplets are important nutrient sources for F. tularensis. We found that F. tularensis-infected cells had increased activation of lipolysis and the upstream regulatory protein AMP protein kinase (AMPK). These data suggest that F. tularensis exploits AMPK activation and lipid metabolism to use host-derived nutrients. Finally, we found that AMPK activation is correlated with an increased bacterial burden, which suggests that it is a host-mediated response to nutrient starvation that results from increased bacterial replication. Altogether, we conclude that F. tularensis exploits AMPK activation to access nutrients sequestered in lipid droplets, specifically glycerol and fatty acids, to undergo efficient bacterial replication and cause successful infection.
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Affiliation(s)
- Sedelia R. Dominguez
- Paul G. Allen School for Global Health, Washington State University, Pullman, Washington, USA
- School of Molecular Biosciences, Washington State University, Pullman, Washington, USA
| | - Shannon Whiles
- Paul G. Allen School for Global Health, Washington State University, Pullman, Washington, USA
| | - Kelly N. Deobald
- Paul G. Allen School for Global Health, Washington State University, Pullman, Washington, USA
| | - Thomas Kawula
- Paul G. Allen School for Global Health, Washington State University, Pullman, Washington, USA
- School of Molecular Biosciences, Washington State University, Pullman, Washington, USA
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7
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Zhao S, Zhang L, Xiang S, Hu Y, Wu Z, Shen J. Gnawing Between Cells and Cells in the Immune System: Friend or Foe? A Review of Trogocytosis. Front Immunol 2022; 13:791006. [PMID: 35185886 PMCID: PMC8850298 DOI: 10.3389/fimmu.2022.791006] [Citation(s) in RCA: 16] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2021] [Accepted: 01/14/2022] [Indexed: 12/27/2022] Open
Abstract
Trogocytosis occurs when one cell contacts and quickly nibbles another cell and is characterized by contact between living cells and rapid transfer of membrane fragments with functional integrity. Many immune cells are involved in this process, such as T cells, B cells, NK cells, APCs. The transferred membrane molecules including MHC molecules, costimulatory molecules, receptors, antigens, etc. An increasing number of studies have shown that trogocytosis plays an important role in the immune system and the occurrence of relevant diseases. Thus, whether trogocytosis is a friend or foe of the immune system is puzzling, and the precise mechanism underlying it has not yet been fully elucidated. Here, we provide an integrated view of the acquired findings on the connections between trogocytosis and the immune system.
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Affiliation(s)
- Siyu Zhao
- Department of Parasitology of Zhongshan School of Medicine, Sun Yat-sen University, Guangzhou, China.,Key Laboratory of Tropical Disease Control (SYSU), Ministry of Education, Guangzhou, China.,Provincial Engineering Technology Research Center for Biological Vector Control, Guangzhou, China
| | - Lichao Zhang
- Department of Parasitology of Zhongshan School of Medicine, Sun Yat-sen University, Guangzhou, China.,Key Laboratory of Tropical Disease Control (SYSU), Ministry of Education, Guangzhou, China.,Provincial Engineering Technology Research Center for Biological Vector Control, Guangzhou, China
| | - Suoyu Xiang
- Department of Parasitology of Zhongshan School of Medicine, Sun Yat-sen University, Guangzhou, China.,Key Laboratory of Tropical Disease Control (SYSU), Ministry of Education, Guangzhou, China.,Provincial Engineering Technology Research Center for Biological Vector Control, Guangzhou, China
| | - Yunyi Hu
- Department of Parasitology of Zhongshan School of Medicine, Sun Yat-sen University, Guangzhou, China.,Key Laboratory of Tropical Disease Control (SYSU), Ministry of Education, Guangzhou, China.,Provincial Engineering Technology Research Center for Biological Vector Control, Guangzhou, China
| | - Zhongdao Wu
- Department of Parasitology of Zhongshan School of Medicine, Sun Yat-sen University, Guangzhou, China.,Key Laboratory of Tropical Disease Control (SYSU), Ministry of Education, Guangzhou, China.,Provincial Engineering Technology Research Center for Biological Vector Control, Guangzhou, China
| | - Jia Shen
- Department of Parasitology of Zhongshan School of Medicine, Sun Yat-sen University, Guangzhou, China.,Key Laboratory of Tropical Disease Control (SYSU), Ministry of Education, Guangzhou, China.,Provincial Engineering Technology Research Center for Biological Vector Control, Guangzhou, China
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8
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The Multiple Roles of Trogocytosis in Immunity, the Nervous System, and Development. BIOMED RESEARCH INTERNATIONAL 2021; 2021:1601565. [PMID: 34604381 PMCID: PMC8483919 DOI: 10.1155/2021/1601565] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/08/2021] [Revised: 09/02/2021] [Accepted: 09/08/2021] [Indexed: 12/24/2022]
Abstract
Trogocytosis is a general biological process that involves one cell physically taking small parts of the membrane and other components from another cell. In trogocytosis, one cell seems to take little “bites” from another cell resulting in multiple outcomes from these cell-cell interactions. Trogocytosis was first described in protozoan parasites, which by taking pieces of host cells, kill them and cause tissue damage. Now, it is known that this process is also performed by cells of the immune system with important consequences such as cell communication and activation, elimination of microbial pathogens, and even control of cancer cells. More recently, trogocytosis has also been reported to occur in cells of the central nervous system and in various cells during development. Some of the molecules involved in phagocytosis also participate in trogocytosis. However, the molecular mechanisms that regulate trogocytosis are still a mystery. Elucidating these mechanisms is becoming a research area of much interest. For example, why neutrophils can engage trogocytosis to kill Trichomonas vaginalis parasites, but neutrophils use phagocytosis to eliminate already death parasites? Thus, trogocytosis is a significant process in normal physiology that multiple cells from different organisms use in various scenarios of health and disease. In this review, we present the basic principles known on the process of trogocytosis and discuss the importance in this process to host-pathogen interactions and to normal functions in the immune and nervous systems.
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9
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Miyake K, Karasuyama H. The Role of Trogocytosis in the Modulation of Immune Cell Functions. Cells 2021; 10:cells10051255. [PMID: 34069602 PMCID: PMC8161413 DOI: 10.3390/cells10051255] [Citation(s) in RCA: 45] [Impact Index Per Article: 15.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2021] [Revised: 05/15/2021] [Accepted: 05/17/2021] [Indexed: 12/16/2022] Open
Abstract
Trogocytosis is an active process, in which one cell extracts the cell fragment from another cell, leading to the transfer of cell surface molecules, together with membrane fragments. Recent reports have revealed that trogocytosis can modulate various biological responses, including adaptive and innate immune responses and homeostatic responses. Trogocytosis is evolutionally conserved from protozoan parasites to eukaryotic cells. In some cases, trogocytosis results in cell death, which is utilized as a mechanism for antibody-dependent cytotoxicity (ADCC). In other cases, trogocytosis-mediated intercellular protein transfer leads to both the acquisition of novel functions in recipient cells and the loss of cellular functions in donor cells. Trogocytosis in immune cells is typically mediated by receptor–ligand interactions, including TCR–MHC interactions and Fcγ receptor-antibody-bound molecule interactions. Additionally, trogocytosis mediates the transfer of MHC molecules to various immune and non-immune cells, which confers antigen-presenting activity on non-professional antigen-presenting cells. In this review, we summarize the recent advances in our understanding of the role of trogocytosis in immune modulation.
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10
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I'm Infected, Eat Me! Innate Immunity Mediated by Live, Infected Cells Signaling To Be Phagocytosed. Infect Immun 2021; 89:IAI.00476-20. [PMID: 33558325 DOI: 10.1128/iai.00476-20] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
Innate immunity against pathogens is known to be mediated by barriers to pathogen invasion, activation of complement, recruitment of immune cells, immune cell phagocytosis of pathogens, death of infected cells, and activation of the adaptive immunity via antigen presentation. Here, we propose and review evidence for a novel mode of innate immunity whereby live, infected host cells induce phagocytes to phagocytose the infected cell, thereby potentially reducing infection. We discuss evidence that host cells, infected by virus, bacteria, or other intracellular pathogens (i) release nucleotides and chemokines as find-me signals, (ii) expose on their surface phosphatidylserine and calreticulin as eat-me signals, (iii) release and bind opsonins to induce phagocytosis, and (iv) downregulate don't-eat-me signals CD47, major histocompatibility complex class I (MHC1), and sialic acid. As long as the pathogens of the host cell are destroyed within the phagocyte, then infection can be curtailed; if antigens from the pathogens are cross-presented by the phagocyte, then an adaptive response would also be induced. Phagocytosis of live infected cells may thereby mediate innate immunity.
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11
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Trogocytosis between Non-Immune Cells for Cell Clearance, and among Immune-Related Cells for Modulating Immune Responses and Autoimmunity. Int J Mol Sci 2021; 22:ijms22052236. [PMID: 33668117 PMCID: PMC7956485 DOI: 10.3390/ijms22052236] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2021] [Revised: 02/21/2021] [Accepted: 02/21/2021] [Indexed: 12/21/2022] Open
Abstract
The term trogocytosis refers to a rapid bidirectional and active transfer of surface membrane fragment and associated proteins between cells. The trogocytosis requires cell-cell contact, and exhibits fast kinetics and the limited lifetime of the transferred molecules on the surface of the acceptor cells. The biological actions of trogocytosis include information exchange, cell clearance of unwanted tissues in embryonic development, immunoregulation, cancer surveillance/evasion, allogeneic cell survival and infectious pathogen killing or intercellular transmission. In the present review, we will extensively review all these aspects. In addition to its biological significance, aberrant trogocytosis in the immune system leading to autoimmunity and immune-mediated inflammatory diseases will also be discussed. Finally, the prospective investigations for further understanding the molecular basis of trogocytosis and its clinical applications will also be proposed.
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12
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Bradford MK, Elkins KL. Immune lymphocytes halt replication of Francisella tularensis LVS within the cytoplasm of infected macrophages. Sci Rep 2020; 10:12023. [PMID: 32694562 PMCID: PMC7374111 DOI: 10.1038/s41598-020-68798-2] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2019] [Accepted: 06/26/2020] [Indexed: 12/18/2022] Open
Abstract
Francisella tularensis is a highly infectious intracellular bacterium that causes tularemia by invading and replicating in mammalian myeloid cells. Francisella primarily invades host macrophages, where it escapes phagosomes within a few hours and replicates in the cytoplasm. Less is known about how Francisella traffics within macrophages or exits into the extracellular environment for further infection. Immune T lymphocytes control the replication of Francisella within macrophages in vitro by a variety of mechanisms, but nothing is known about intracellular bacterial trafficking in the face of such immune pressure. Here we used a murine model of infection with a Francisella attenuated live vaccine strain (LVS), which is under study as a human vaccine, to evaluate the hypothesis that immune T cells control intramacrophage bacterial growth by re-directing bacteria into toxic intracellular compartments of infected macrophages. We visualized the interactions of lymphocytes and LVS-infected macrophages using confocal microscopy and characterized LVS intramacrophage trafficking when co-cultured with immune lymphocytes. We focused on the late stages of infection after bacteria escape from phagosomes, through bacterial replication and the death of macrophages. We found that the majority of LVS remained cytosolic in the absence of immune pressure, eventually resulting in macrophage death. In contrast, co-culture of LVS-infected macrophages with LVS-immune lymphocytes halted LVS replication and inhibited the spread of LVS infection between macrophages, but bacteria did not return to vacuoles such as lysosomes or autophagosomes and macrophages did not die. Therefore, immune lymphocytes directly limit intracellular bacterial replication within the cytoplasm of infected macrophages.
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Affiliation(s)
- Mary Katherine Bradford
- Laboratory of Mucosal Pathogens and Cellular Immunology, Division of Bacterial, Parasitic and Allergenic Products, Center for Biologics Evaluation and Research, U.S. Food and Drug Administration, Silver Spring, MD, 20993, USA.,Johns Hopkins University Professional Development and Career Office, 1830 E. Monument, 2-107, Baltimore, MD, 21287, USA
| | - Karen L Elkins
- Laboratory of Mucosal Pathogens and Cellular Immunology, Division of Bacterial, Parasitic and Allergenic Products, Center for Biologics Evaluation and Research, U.S. Food and Drug Administration, Silver Spring, MD, 20993, USA.
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13
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Biting Off What Can Be Chewed: Trogocytosis in Health, Infection, and Disease. Infect Immun 2020; 88:IAI.00930-19. [PMID: 32366574 DOI: 10.1128/iai.00930-19] [Citation(s) in RCA: 23] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
Trogocytosis is part of an emerging, exciting theme of cell-cell interactions both within and between species, and it is relevant to host-pathogen interactions in many different contexts. Trogocytosis is a process in which one cell physically extracts and ingests "bites" of cellular material from another cell. It was first described in eukaryotic microbes, where it was uncovered as a mechanism by which amoebae kill cells. Trogocytosis is potentially a fundamental form of eukaryotic cell-cell interaction, since it also occurs in multicellular organisms, where it has functions in the immune system, in the central nervous system, and during development. There are numerous scenarios in which trogocytosis occurs and an ever-evolving list of functions associated with this process. Many aspects of trogocytosis are relevant to microbial pathogenesis. It was recently discovered that immune cells perform trogocytosis to kill Trichomonas vaginalis parasites. Additionally, through trogocytosis, Entamoeba histolytica acquires and displays human cell membrane proteins, enabling immune evasion. Intracellular bacteria seem to exploit host cell trogocytosis, since they can use it to spread from cell to cell. Thus, a picture is emerging in which trogocytosis plays critical roles in normal physiology, infection, and disease.
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Dominguez SR, Kawula T, Steele SP. Bacterial Synchronized Transfer Assays in Bone Marrow Derived Macrophages. Bio Protoc 2019; 9:e3437. [PMID: 33117859 DOI: 10.21769/bioprotoc.3437] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022] Open
Abstract
Merocytophagy ("mero", Greek for partial; "cytophagy" for cell eating) is a process by which cells acquire microbes and cytosolic material through phagocytosis of a small portion of neighboring cells upon cell-cell contact. Cell-cell contact dependent transfer events can be assessed through co-incubation of differently labeled cells. With these assays, it is difficult to analyze the recipient cells by microscopy or bacterial burden within only recipient cells. Therefore, we established a synchronized transfer assay that allows for recipient cells to be isolated from donor cells following transfer events at a high purity. Here, we present this assay in context of bacterial infections and cytosolic cellular staining. With this protocol, mechanisms of cell-cell contact dependent transfer events and the events following merocytophagy can easily be investigated.
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Affiliation(s)
- Sedelia R Dominguez
- Paul G Allen School of Global Animal Health, Washington State University, Pullman, United States
| | - Tom Kawula
- Paul G Allen School of Global Animal Health, Washington State University, Pullman, United States
| | - Shaun P Steele
- Paul G Allen School of Global Animal Health, Washington State University, Pullman, United States
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