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Rouvray S, Drummond RA. The role of lipids in regulating macrophage antifungal immunity. mBio 2024:e0305723. [PMID: 39207168 DOI: 10.1128/mbio.03057-23] [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: 09/04/2024] Open
Abstract
Macrophages are critical components of the antifungal immune response. Disturbance in the number or function of these innate immune cells can significantly increase susceptibility to invasive fungal infections. Pathogenic fungi cause billions of infections every year and have an unmet clinical need, with many infections associated with unacceptably high mortality rates that primarily affect vulnerable patients with underlying immune defects. Lipid metabolism has been increasingly appreciated to significantly influence macrophage function, particularly of macrophages residing in lipid-rich organs, such as the brain, or macrophages specialized at clearing dead cells including alveolar macrophages in the lungs. In this review, we provide an overview of macrophage lipid metabolism, and discuss how lipid recycling and dysregulation affect key macrophage functions relevant for antifungal immunity including phagocytosis, functional polarization, and inflammasome activation. We focus on the fungal pathogen Cryptococcus neoformans, as this is the most common cause of death from fungal infection in humans and because several lines of evidence have already linked lipid metabolism in the regulation of C. neoformans and macrophage interactions.
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Affiliation(s)
- Sophie Rouvray
- Institute of Immunology and Immunotherapy, University of Birmingham, Birmingham, United Kingdom
| | - Rebecca A Drummond
- Institute of Immunology and Immunotherapy, University of Birmingham, Birmingham, United Kingdom
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2
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Sonnberger J, Kasper L, Lange T, Brunke S, Hube B. "We've got to get out"-Strategies of human pathogenic fungi to escape from phagocytes. Mol Microbiol 2024; 121:341-358. [PMID: 37800630 DOI: 10.1111/mmi.15149] [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: 06/30/2023] [Revised: 08/08/2023] [Accepted: 08/16/2023] [Indexed: 10/07/2023]
Abstract
Human fungal pathogens are a deadly and underappreciated risk to global health that most severely affect immunocompromised individuals. A virulence attribute shared by some of the most clinically relevant fungal species is their ability to survive inside macrophages and escape from these immune cells. In this review, we discuss the mechanisms behind intracellular survival and elaborate how escape is mediated by lytic and non-lytic pathways as well as strategies to induce programmed host cell death. We also discuss persistence as an alternative to rapid host cell exit. In the end, we address the consequences of fungal escape for the host immune response and provide future perspectives for research and development of targeted therapies.
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Affiliation(s)
- Johannes Sonnberger
- Department of Microbial Pathogenicity Mechanisms, Hans Knoell Institute, Jena, Germany
| | - Lydia Kasper
- Department of Microbial Pathogenicity Mechanisms, Hans Knoell Institute, Jena, Germany
| | - Theresa Lange
- Department of Microbial Pathogenicity Mechanisms, Hans Knoell Institute, Jena, Germany
| | - Sascha Brunke
- Department of Microbial Pathogenicity Mechanisms, Hans Knoell Institute, Jena, Germany
| | - Bernhard Hube
- Department of Microbial Pathogenicity Mechanisms, Hans Knoell Institute, Jena, Germany
- Institute of Microbiology, Friedrich Schiller University, Jena, Germany
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3
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Le J, Kulatheepan Y, Jeyaseelan S. Role of toll-like receptors and nod-like receptors in acute lung infection. Front Immunol 2023; 14:1249098. [PMID: 37662905 PMCID: PMC10469605 DOI: 10.3389/fimmu.2023.1249098] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2023] [Accepted: 07/28/2023] [Indexed: 09/05/2023] Open
Abstract
The respiratory system exposed to microorganisms continuously, and the pathogenicity of these microbes not only contingent on their virulence factors, but also the host's immunity. A multifaceted innate immune mechanism exists in the respiratory tract to cope with microbial infections and to decrease tissue damage. The key cell types of the innate immune response are macrophages, neutrophils, dendritic cells, epithelial cells, and endothelial cells. Both the myeloid and structural cells of the respiratory system sense invading microorganisms through binding or activation of pathogen-associated molecular patterns (PAMPs) to pattern recognition receptors (PRRs), including Toll-like receptors (TLRs) and NOD-like receptors (NLRs). The recognition of microbes and subsequent activation of PRRs triggers a signaling cascade that leads to the activation of transcription factors, induction of cytokines/5chemokines, upregulation of cell adhesion molecules, recruitment of immune cells, and subsequent microbe clearance. Since numerous microbes resist antimicrobial agents and escape innate immune defenses, in the future, a comprehensive strategy consisting of newer vaccines and novel antimicrobials will be required to control microbial infections. This review summarizes key findings in the area of innate immune defense in response to acute microbial infections in the lung. Understanding the innate immune mechanisms is critical to design host-targeted immunotherapies to mitigate excessive inflammation while controlling microbial burden in tissues following lung infection.
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Affiliation(s)
- John Le
- Laboratory of Lung Biology, Department of Pathobiological Sciences and Center for Lung Biology and Disease, School of Veterinary Medicine, Louisiana State University (LSU) and Agricultural & Mechanical College, Baton Rouge, LA, United States
| | - Yathushigan Kulatheepan
- Laboratory of Lung Biology, Department of Pathobiological Sciences and Center for Lung Biology and Disease, School of Veterinary Medicine, Louisiana State University (LSU) and Agricultural & Mechanical College, Baton Rouge, LA, United States
| | - Samithamby Jeyaseelan
- Laboratory of Lung Biology, Department of Pathobiological Sciences and Center for Lung Biology and Disease, School of Veterinary Medicine, Louisiana State University (LSU) and Agricultural & Mechanical College, Baton Rouge, LA, United States
- Section of Pulmonary and Critical Care Department of Medicine, LSU Health Sciences Center, New Orleans, LA, United States
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4
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Lange T, Kasper L, Gresnigt MS, Brunke S, Hube B. "Under Pressure" - How fungi evade, exploit, and modulate cells of the innate immune system. Semin Immunol 2023; 66:101738. [PMID: 36878023 PMCID: PMC10109127 DOI: 10.1016/j.smim.2023.101738] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/06/2022] [Indexed: 03/06/2023]
Abstract
The human immune system uses an arsenal of effector mechanisms to prevent and counteract infections. Yet, some fungal species are extremely successful as human pathogens, which can be attributed to a wide variety of strategies by which these fungi evade, exploit, and modulate the immune system. These fungal pathogens normally are either harmless commensals or environmental fungi. In this review we discuss how commensalism, but also life in an environmental niche without human contact, can drive the evolution of diverse and specialized immune evasion mechanisms. Correspondingly, we discuss the mechanisms contributing to the ability of these fungi to cause superficial to life-threatening infections.
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Affiliation(s)
- Theresa Lange
- Department of Microbial Pathogenicity Mechanisms, Hans Knoell Institute, Jena, Germany
| | - Lydia Kasper
- Department of Microbial Pathogenicity Mechanisms, Hans Knoell Institute, Jena, Germany
| | - Mark S Gresnigt
- Junior Research Group Adaptive Pathogenicity Strategies, Hans Knoell Institute, Jena, Germany
| | - Sascha Brunke
- Department of Microbial Pathogenicity Mechanisms, Hans Knoell Institute, Jena, Germany
| | - Bernhard Hube
- Department of Microbial Pathogenicity Mechanisms, Hans Knoell Institute, Jena, Germany; Institute of Microbiology, Friedrich Schiller University, Jena, Germany.
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5
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Sato K, Kawakami K. PAMPs and Host Immune Response in Cryptococcal Infection. Med Mycol J 2022; 63:133-138. [DOI: 10.3314/mmj.22.005] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/03/2022]
Affiliation(s)
- Ko Sato
- Department of Medical Microbiology, Mycology and Immunology, Tohoku University Graduate School of Medicine
| | - Kazuyoshi Kawakami
- Department of Medical Microbiology, Mycology and Immunology, Tohoku University Graduate School of Medicine
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6
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Abstract
Cryptococcosis is a disease caused by the pathogenic fungi Cryptococcus neoformans and Cryptococcus gattii, both environmental fungi that cause severe pneumonia and may even lead to cryptococcal meningoencephalitis. Although C. neoformans affects more fragile individuals, such as immunocompromised hosts through opportunistic infections, C. gattii causes a serious indiscriminate primary infection in immunocompetent individuals. Typically seen in tropical and subtropical environments, C. gattii has increased its endemic area over recent years, largely due to climatic factors that favor contagion in warmer climates. It is important to point out that not only C. gattii, but the Cryptococcus species complex produces a polysaccharidic capsule with immunomodulatory properties, enabling the pathogenic species of Cryptococccus to subvert the host immune response during the establishment of cryptococcosis, facilitating its dissemination in the infected organism. C. gattii causes a more severe and difficult-to-treat infection, with few antifungals eliciting an effective response during chronic treatment. Much of the immunopathology of this cryptococcosis is still poorly understood, with most studies focusing on cryptococcosis caused by the species C. neoformans. C. gattii became more important in the epidemiological scenario with the outbreaks in the Pacific Northwest of the United States, which resulted in phylogenetic studies of the virulent variant responsible for the severe infection in the region. Since then, the study of cryptococcosis caused by C. gattii has helped researchers understand the immunopathological aspects of different variants of this pathogen.
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The Inflammasome NLRC4 Protects against Cryptococcus gattii by Inducing the Classic Caspase-1 to Activate the Pyroptosis Signal. JOURNAL OF HEALTHCARE ENGINEERING 2022; 2022:7355485. [PMID: 35340249 PMCID: PMC8942663 DOI: 10.1155/2022/7355485] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/30/2022] [Accepted: 02/16/2022] [Indexed: 12/12/2022]
Abstract
Cryptococcus is one of the most pathogenic invasive fungi, and its interaction with the host's natural immunity, especially the role of the inflammasome family, has not been fully elucidated. As an important member of the inflammasome family, NOD-like receptor (NLR) family caspase recruitment domain (CARD) containing 4 (NLRC4) has been proven to protect lungs from damage from a variety of pathogens. In this study, we investigated the protective effect and mechanism of NLRC4 on cryptococcal pulmonary infection using NLRC4-/-mice in vivo and NLRC4-/-macrophages in vitro models stimulated by cryptococcal cells. We apply small animal fluorescence imaging to detect the fungal burden in the lungs and living body micro-CT scans of mice and in vitro tissue micro-CT scans to compare differences in infection foci nodules and histopathological lesions, and the activation of caspase-1 and downstream cytokines were detected by Western bolt and ELISA, etc. The results demonstrated that cryptococcal infection can activate the Nod-like receptors of caspase-1 activation and NLRC4 inflammasomes in macrophages and dendritic cells and affect downstream IL-1β and IL-18 release. After cryptococcal infection, the survival rate, lung fungal burden, and histopathological damage of NLRC4−/− mice were significantly impaired. NLRC4−/− macrophages showed a lower release of inflammatory factors, reactive oxygen species (ROS), and lactate dehydrogenase (LDH). Collectively, our results demonstrated that the activation of caspase-1 and downstream cytokines mediated by NLRC4 inflammasome in immune cells during Cryptococcus infection can enhance pyroptosis of macrophages, affect the phagocytic ability of macrophages, and inhibit the intracellular parasitism of cryptococcus, eventually reducing the burden of fungi.
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8
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Last A, Maurer M, S. Mosig A, S. Gresnigt M, Hube B. In vitro infection models to study fungal-host interactions. FEMS Microbiol Rev 2021; 45:fuab005. [PMID: 33524102 PMCID: PMC8498566 DOI: 10.1093/femsre/fuab005] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2020] [Accepted: 01/14/2021] [Indexed: 12/14/2022] Open
Abstract
Fungal infections (mycoses) affect over a billion people per year. Approximately, two million of these infections are life-threatening, especially for patients with a compromised immune system. Fungi of the genera Aspergillus, Candida, Histoplasma and Cryptococcus are opportunistic pathogens that contribute to a substantial number of mycoses. To optimize the diagnosis and treatment of mycoses, we need to understand the complex fungal-host interplay during pathogenesis, the fungal attributes causing virulence and how the host resists infection via immunological defenses. In vitro models can be used to mimic fungal infections of various tissues and organs and the corresponding immune responses at near-physiological conditions. Furthermore, models can include fungal interactions with the host-microbiota to mimic the in vivo situation on skin and mucosal surfaces. This article reviews currently used in vitro models of fungal infections ranging from cell monolayers to microfluidic 3D organ-on-chip (OOC) platforms. We also discuss how OOC models can expand the toolbox for investigating interactions of fungi and their human hosts in the future.
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Affiliation(s)
- Antonia Last
- Department of Microbial Pathogenicity Mechanisms, Leibniz Institute for Natural Product Research and Infection Biology—Hans Knoell Institute, Beutenbergstrasse 11a, 07745, Jena, Germany
| | - Michelle Maurer
- Center for Sepsis Control and Care (CSCC), Jena University Hospital, Am Klinikum 1, 07747, Jena, Germany
- Institute of Biochemistry II, Jena University Hospital, Nonnenplan 2,07743, Jena, Germany
| | - Alexander S. Mosig
- Center for Sepsis Control and Care (CSCC), Jena University Hospital, Am Klinikum 1, 07747, Jena, Germany
- Institute of Biochemistry II, Jena University Hospital, Nonnenplan 2,07743, Jena, Germany
| | - Mark S. Gresnigt
- Junior Research Group Adaptive Pathogenicity Strategies, Leibniz Institute for Natural Product Research and Infection Biology—Hans Knoell Institute, Beutenbergstrasse 11a, 07745, Jena, Germany
| | - Bernhard Hube
- Department of Microbial Pathogenicity Mechanisms, Leibniz Institute for Natural Product Research and Infection Biology—Hans Knoell Institute, Beutenbergstrasse 11a, 07745, Jena, Germany
- Institute of Microbiology, Friedrich Schiller University, Neugasse 24, 07743, Jena, Germany
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9
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Williams TJ, Gonzales-Huerta LE, Armstrong-James D. Fungal-Induced Programmed Cell Death. J Fungi (Basel) 2021; 7:jof7030231. [PMID: 33804601 PMCID: PMC8003624 DOI: 10.3390/jof7030231] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2021] [Revised: 03/17/2021] [Accepted: 03/18/2021] [Indexed: 01/01/2023] Open
Abstract
Fungal infections are a cause of morbidity in humans, and despite the availability of a range of antifungal treatments, the mortality rate remains unacceptably high. Although our knowledge of the interactions between pathogenic fungi and the host continues to grow, further research is still required to fully understand the mechanism underpinning fungal pathogenicity, which may provide new insights for the treatment of fungal disease. There is great interest regarding how microbes induce programmed cell death and what this means in terms of the immune response and resolution of infection as well as microbe-specific mechanisms that influence cell death pathways to aid in their survival and continued infection. Here, we discuss how programmed cell death is induced by fungi that commonly cause opportunistic infections, including Candida albicans, Aspergillus fumigatus, and Cryptococcus neoformans, the role of programmed cell death in fungal immunity, and how fungi manipulate these pathways.
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10
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Briard B, Malireddi RKS, Kanneganti TD. Role of inflammasomes/pyroptosis and PANoptosis during fungal infection. PLoS Pathog 2021; 17:e1009358. [PMID: 33735255 PMCID: PMC7971547 DOI: 10.1371/journal.ppat.1009358] [Citation(s) in RCA: 36] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Affiliation(s)
- Benoit Briard
- Department of Immunology, St. Jude Children’s Research Hospital, Memphis, Tennessee, United States of America
| | - R. K. Subbarao Malireddi
- Department of Immunology, St. Jude Children’s Research Hospital, Memphis, Tennessee, United States of America
| | - Thirumala-Devi Kanneganti
- Department of Immunology, St. Jude Children’s Research Hospital, Memphis, Tennessee, United States of America
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11
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Tyrkalska SD, Candel S, Mulero V. The neutrophil inflammasome. DEVELOPMENTAL AND COMPARATIVE IMMUNOLOGY 2021; 115:103874. [PMID: 32987011 DOI: 10.1016/j.dci.2020.103874] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/03/2020] [Revised: 09/21/2020] [Accepted: 09/21/2020] [Indexed: 06/11/2023]
Abstract
Since inflammasomes were discovered in the early 21st century, knowledge about their biology has multiplied exponentially. These cytosolic multiprotein complexes alert the immune system about the presence of infection or tissue damage, and regulate the subsequent inflammatory responses. As inflammasome dysregulation is increasingly associated with numerous autoinflammatory disorders, there is an urgent need for further research into the inflammasome's involvement in the pathogenesis of such diseases in order to identify novel therapeutic targets and treatments. The zebrafish has become a widely used animal model to study human diseases in recent years, and has already provided relevant findings in the field of inflammasome biology including the identification of new components and pathways. We provide a detailed analysis of current knowledge on neutrophil inflammasome biology and compare its features with those of the better known macrophage inflammasome, focusing on its contribution to innate immunity and its relevance for human health. Importantly, a large body of evidence points to a link between neutrophil inflammasome dysfunction and many neutrophil-mediated human diseases, but the real contribution of the neutrophil inflammasome to the pathogenesis of these disorders is largely unknown. Although neutrophils have remained in the shadow of macrophages and monocytes in the field of inflammasome research since the discovery of these multiprotein platforms, recent studies strongly suggest that the importance of the neutrophil inflammasome has been underestimated.
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Affiliation(s)
- Sylwia D Tyrkalska
- Departamento de Biología Celular e Histología, Facultad de Biología, Universidad de Murcia, Spain; Instituto Murciano de Investigación Biosanitaria (IMIB)-Arrixaca, Murcia, Spain.
| | - Sergio Candel
- Departamento de Biología Celular e Histología, Facultad de Biología, Universidad de Murcia, Spain; Instituto Murciano de Investigación Biosanitaria (IMIB)-Arrixaca, Murcia, Spain.
| | - Victoriano Mulero
- Departamento de Biología Celular e Histología, Facultad de Biología, Universidad de Murcia, Spain; Instituto Murciano de Investigación Biosanitaria (IMIB)-Arrixaca, Murcia, Spain; Centro de Investigación Biomédica en Red de Enfermedades Raras (CIBERER), Spain.
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12
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Cryptococcus neoformans Secretes Small Molecules That Inhibit IL-1 β Inflammasome-Dependent Secretion. Mediators Inflamm 2020; 2020:3412763. [PMID: 33380899 PMCID: PMC7748918 DOI: 10.1155/2020/3412763] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2020] [Revised: 10/22/2020] [Accepted: 11/04/2020] [Indexed: 01/22/2023] Open
Abstract
Cryptococcus neoformans is an encapsulated yeast that causes disease mainly in immunosuppressed hosts. It is considered a facultative intracellular pathogen because of its capacity to survive and replicate inside phagocytes, especially macrophages. This ability is heavily dependent on various virulence factors, particularly the glucuronoxylomannan (GXM) component of the polysaccharide capsule. Inflammasome activation in phagocytes is usually protective against fungal infections, including cryptococcosis. Nevertheless, recognition of C. neoformans by inflammasome receptors requires specific changes in morphology or the opsonization of the yeast, impairing proper inflammasome function. In this context, we analyzed the impact of molecules secreted by C. neoformans B3501 strain and its acapsular mutant Δcap67 in inflammasome activation in an in vitro model. Our results showed that conditioned media derived from B3501 was capable of inhibiting inflammasome-dependent events (i.e., IL-1β secretion and LDH release via pyroptosis) more strongly than conditioned media from Δcap67, regardless of GXM presence. We also demonstrated that macrophages treated with conditioned media were less responsive against infection with the virulent strain H99, exhibiting lower rates of phagocytosis, increased fungal burdens, and enhanced vomocytosis. Moreover, we showed that the aromatic metabolite DL-Indole-3-lactic acid (ILA) and DL-p-Hydroxyphenyllactic acid (HPLA) were present in B3501's conditioned media and that ILA alone or with HPLA is involved in the regulation of inflammasome activation by C. neoformans. These results were confirmed by in vivo experiments, where exposure to conditioned media led to higher fungal burdens in Acanthamoeba castellanii culture as well as in higher fungal loads in the lungs of infected mice. Overall, the results presented show that conditioned media from a wild-type strain can inhibit a vital recognition pathway and subsequent fungicidal functions of macrophages, contributing to fungal survival in vitro and in vivo and suggesting that secretion of aromatic metabolites, such as ILA, during cryptococcal infections fundamentally impacts pathogenesis.
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13
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Abstract
Respiratory fungal infection is a severe clinical problem, especially in patients with compromised immune functions. Aspergillus, Cryptococcus, Pneumocystis, and endemic fungi are major pulmonary fungal pathogens that are able to result in life-threatening invasive diseases. Growing data being reported have indicated that multiple cells and molecules orchestrate the host's response to a fungal infection in the lung. Upon fungal challenge, innate myeloid cells including macrophages, dendritic cells (DC), and recruited neutrophils establish the first line of defense through the phagocytosis and secretion of cytokines. Natural killer cells control the fungal expansion in the lung via the direct and indirect killing of invading organisms. Adaptive immune cells including Th1 and Th17 cells confer anti-fungal activity by producing their signature cytokines, interferon-γ, and IL-17. In addition, lung epithelial cells (LEC) also participate in the resistance against fungal infection by internalization, inflammatory cytokine production, or antimicrobial peptide secretion. In the host cells mentioned above, various molecules with distinct functions modulate the immune defense signaling: Pattern recognition receptors (PRRs) such as dectin-1 expressed on the cell surface are involved in fungal recognition; adaptor proteins such as MyD88 and TRAF6 are required for transduction of signals to the nucleus for transcriptional regulation; inflammasomes also play crucial roles in the host's defense against a fungal infection in the lung. Furthermore, transcriptional factors modulate the transcriptions of a series of genes, especially those encoding cytokines and chemokines, which are predominant regulators in the infectious microenvironment, mediating the cellular and molecular immune responses against a fungal infection in the lung.
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Affiliation(s)
- Zhi Li
- The Joint Center for Infection and Immunity, Guangzhou Women and Children's Medical Center, Guangzhou Institute of Pediatrics, Guangzhou, China
- The Joint Center for Infection and Immunity, Institute Pasteur of Shanghai, Chinese Academy of Science, Shanghai, China
| | - Gen Lu
- The Joint Center for Infection and Immunity, Guangzhou Women and Children's Medical Center, Guangzhou Institute of Pediatrics, Guangzhou, China
| | - Guangxun Meng
- The Joint Center for Infection and Immunity, Institute Pasteur of Shanghai, Chinese Academy of Science, Shanghai, China
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14
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Abstract
For pathogenic microbes to survive ingestion by macrophages, they must subvert powerful microbicidal mechanisms within the phagolysosome. After ingestion, Candida albicans undergoes a morphological transition producing hyphae, while the surrounding phagosome exhibits a loss of phagosomal acidity. However, how these two events are related has remained enigmatic. Now Westman et al. (mBio 9:e01226-18, 2018, https://doi.org/10.1128/mBio.01226-18) report that phagosomal neutralization results from disruption of phagosomal membrane integrity by the enlarging hyphae, directly implicating the morphological transition in physical damage that promotes intracellular survival. The C. albicans intracellular strategy shows parallels with another fungal pathogen, Cryptococcus neoformans, where a morphological changed involving capsular enlargement intracellularly is associated with loss of membrane integrity and death of the host cell. These similarities among distantly related pathogenic fungi suggest that morphological transitions that are common in fungi directly affect the outcome of the fungal cell-macrophage interaction. For this class of organisms, form determines fate in the intracellular environment.
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15
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Fungal β-Glucan Activates the NLRP3 Inflammasome in Human Bronchial Epithelial Cells Through ROS Production. Inflammation 2018; 41:164-173. [PMID: 29063476 DOI: 10.1007/s10753-017-0674-6] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
The nucleotide-binding domain and leucine-rich repeat protein 3 (NLRP3) inflammasome has developed as an important bridge between innate immune and infection recently, and has the ability to drive proteolytic procaspase-1 into bioactive caspase-1, then responsible for proteolytic processing of inflammatory cytokines IL-1β and IL-18. Fungal β-glucan, a major component of fungal cell wall, triggers inflammatory response in multiple immune cells, but rarely described in epithelial cells. Also, the relationship between fungal β-glucan and NLRP3 inflammasome is not clear yet. In this study, we first identified that curdlan, a large particulate β-glucan, could activate the NLRP3 inflammasome in LPS-primed human bronchial epithelial cells (HBECs). RT-PCR and Western Blot showed that curdlan upregulate the mRNA as well as intracellular protein expression of NLRP3 and IL-1β in HBECs, along with the activity of caspase-1, and the level of mature IL-1β in cell supernatants was higher by ELISA detection. Further studies demonstrated that the activation of NLRP3 inflammasome could be attenuated by NAC, an inhibitor of ROS. Thus, it indicated curdlan activate NLRP3 inflammasome through a pathway requiring ROS production in HBECs. These findings may provide a new therapeutic target, NLRP3 inflammasome, in invasive pulmonary fungal infections.
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16
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Cytosolic Recognition of Microbes and Pathogens: Inflammasomes in Action. Microbiol Mol Biol Rev 2018; 82:82/4/e00015-18. [PMID: 30209070 DOI: 10.1128/mmbr.00015-18] [Citation(s) in RCA: 108] [Impact Index Per Article: 18.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
Infection is a dynamic biological process underpinned by a complex interplay between the pathogen and the host. Microbes from all domains of life, including bacteria, viruses, fungi, and protozoan parasites, have the capacity to cause infection. Infection is sensed by the host, which often leads to activation of the inflammasome, a cytosolic macromolecular signaling platform that mediates the release of the proinflammatory cytokines interleukin-1β (IL-1β) and IL-18 and cleavage of the pore-forming protein gasdermin D, leading to pyroptosis. Host-mediated sensing of the infection occurs when pathogens inject or carry pathogen-associated molecular patterns (PAMPs) into the cytoplasm or induce damage that causes cytosolic liberation of danger-associated molecular patterns (DAMPs) in the host cell. Recognition of PAMPs and DAMPs by inflammasome sensors, including NLRP1, NLRP3, NLRC4, NAIP, AIM2, and Pyrin, initiates a cascade of events that culminate in inflammation and cell death. However, pathogens can deploy virulence factors capable of minimizing or evading host detection. This review presents a comprehensive overview of the mechanisms of microbe-induced activation of the inflammasome and the functional consequences of inflammasome activation in infectious diseases. We also explore the microbial strategies used in the evasion of inflammasome sensing at the host-microbe interaction interface.
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17
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A Genome-Wide Screen of Deletion Mutants in the Filamentous Saccharomyces cerevisiae Background Identifies Ergosterol as a Direct Trigger of Macrophage Pyroptosis. mBio 2018; 9:mBio.01204-18. [PMID: 30065091 PMCID: PMC6069111 DOI: 10.1128/mbio.01204-18] [Citation(s) in RCA: 35] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
Phagocytic cells such as macrophages play an important role in the host defense mechanisms mounted in response to the common human fungal pathogen Candida albicans. In vitro, C. albicans triggers macrophage NLRP3-Casp1/11-mediated pyroptosis, an inflammatory programmed cell death pathway. Here, we provide evidence that Casp1/11-dependent pyroptosis occurs in the kidney of infected mice during the early stages of infection. We have also used a genome-wide screen of nonessential Σ1278b Saccharomyces cerevisiae genes to identify genes required for yeast-triggered macrophage pyroptosis. The set of genes identified by this screen was enriched for those with functions in lipid and sterol homeostasis and trafficking. These observations led us to discover that cell surface localization and/or total levels of ergosterol correlate with the ability of S. cerevisiae, C. albicans, and Cryptococcus neoformans to trigger pyroptosis. Since the mammalian sterol cholesterol triggers NLRP3-mediated pyroptosis, we hypothesized that ergosterol may also do so. Consistent with that hypothesis, ergosterol-containing liposomes but not ergosterol-free liposomes induce pyroptosis. Cell wall mannoproteins directly bind ergosterol, and we found that Dan1, an ergosterol receptor mannoprotein, as well as specific mannosyltransferases, is required for pyroptosis, suggesting that cell wall-associated ergosterol may mediate the process. Taken together, these data indicate that ergosterol, like mammalian cholesterol, plays a direct role in yeast-mediated pyroptosis. Innate immune cells such as macrophages are key components of the host response to the human fungal pathogen Candida albicans. Macrophages undergo pyroptosis, an inflammatory, programmed cell death, in response to some species of pathogenic yeast. Prior to the work described in this report, yeast-triggered pyroptosis has been observed only in vitro; here, we show that pyroptosis occurs in the initial stages of murine kidney infection, suggesting that it plays an important role in the initial response of the innate immune system to invasive yeast infection. We also show that a key component of the fungal plasma membrane, ergosterol, directly triggers pyroptosis. Ergosterol is also present in the fungal cell wall, most likely associated with mannoproteins, and is increased in hyphal cells compared to yeast cells. Our data indicate that specific mannoproteins are required for pyroptosis. This is consistent with a potential mechanism whereby ergosterol present in the outer mannoprotein layer of the cell wall is accessible to the macrophage-mediated process. Taken together, our data provide the first evidence that ergosterol plays a direct role in the host-pathogen interactions of fungi.
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de Castro LF, Longhi LNA, Paião MR, Justo-Júnior ADS, de Jesus MB, Blotta MHDSL, Mamoni RL. NLRP3 inflammasome is involved in the recognition of Paracoccidioides brasiliensis by human dendritic cells and in the induction of Th17 cells. J Infect 2018; 77:137-144. [PMID: 29746940 DOI: 10.1016/j.jinf.2018.03.004] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2017] [Revised: 03/18/2018] [Accepted: 03/20/2018] [Indexed: 01/24/2023]
Abstract
OBJECTIVES To investigate the involvement of NLRP3 in the effector functions of human dendritic cells (DCs) in response to Paracoccidioides brasiliensis yeast cells (Pb) and to evaluate its role in the modulation of the adaptive immune response. METHODS DCs were differentiated from purified peripheral blood monocytes and analyzed in relation to the participation of TLR-2, dectin-1, and Syk in Pb recognition, as well as, the indirect mechanisms (Reactive Oxygen Species production, endosome acidification, or K+ efflux) involved in NLRP3 inflammasome activation after the stimulus with Pb. Additionally, we analyzed the role of NLRP3 in the activation of T cells. RESULTS Our results demonstrated that the NLRP3 inflammasome activation and cytokines production by DCs are dependent on ROS generation, endosome acidification, and K+ efflux and involve the Pb recognition by dectin-1 and Syk phosphorylation. Our data also demonstrate that the NLRP3 inflammasome is essential for the activation/expansion of Th1/Th17 cells and its inhibition leads to an increased frequency of Th2 and Treg cells. CONCLUSION Altogether our data indicated that activation of NLRP3 presents an important role in both the induction of the initial inflammatory response and in the development of the acquired immune response associated with resistance to infection.
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Affiliation(s)
- Lívia Furquim de Castro
- Department of Clinical Pathology, Faculty of Medical Sciences, University of Campinas (UNICAMP), Campinas, SP, Brazil
| | - Larissa Nara Alegrini Longhi
- Department of Clinical Pathology, Faculty of Medical Sciences, University of Campinas (UNICAMP), Campinas, SP, Brazil
| | - Munir Regini Paião
- Department of Clinical Pathology, Faculty of Medical Sciences, University of Campinas (UNICAMP), Campinas, SP, Brazil
| | - Amauri da Silva Justo-Júnior
- Department of Clinical Pathology, Faculty of Medical Sciences, University of Campinas (UNICAMP), Campinas, SP, Brazil
| | - Marcelo Bispo de Jesus
- Department of Biochemistry and Tissue Biology, Institute of Biology, University of Campinas (UNICAMP), Campinas, SP, Brazil
| | | | - Ronei Luciano Mamoni
- Department of Clinical Pathology, Faculty of Medical Sciences, University of Campinas (UNICAMP), Campinas, SP, Brazil; Department of Morphology and Basic Pathology, Faculty of Medicine of Jundiaí (FMJ), Jundiaí, SP, Brazil.
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Elsegeiny W, Marr KA, Williamson PR. Immunology of Cryptococcal Infections: Developing a Rational Approach to Patient Therapy. Front Immunol 2018; 9:651. [PMID: 29670625 PMCID: PMC5893745 DOI: 10.3389/fimmu.2018.00651] [Citation(s) in RCA: 64] [Impact Index Per Article: 10.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2018] [Accepted: 03/16/2018] [Indexed: 12/13/2022] Open
Abstract
Cryptococcal meningoencephalitis is responsible for upwards of 15% of HIV-related deaths worldwide and is currently the most common cause of non-viral meningitis in the US, affecting both previously healthy and people with immune suppression caused by cancer chemotherapy, transplantation, and biologic therapies. Despite a continued 30-50% attributable mortality, recommended therapeutic strategies have remained largely unchanged since the 1950s. Recent murine models and human studies examining the role of the immune system in both susceptibility to the infection as well as host damage have begun to influence patient care decisions. The Damage Framework Response, originally proposed in 1999, was recently used to discuss dichotomous etiologies of host damage in cryptococcal disease. These include patients suffering microbiological damage with low host immunity (especially those immunosuppressed with HIV) and those having low (live) microbiological burden but high immune-mediated damage (HIV-related immune reconstitution syndrome and non-HIV-related postinfectious inflammatory response syndrome). Cryptococcal disease in previously healthy hosts, albeit rare, has been known for a long time. Immunophenotyping and dendritic cell-T cell signaling studies on cerebral spinal fluid of these rare patients reveal immune capacity for recognition and T-cell activation pathways including increased levels of HLA-DR and CD56. However, despite effective T-cell signals, brain biopsy and autopsy specimens demonstrated an M2 alternative macrophage polarization and poor phagocytosis of fungal cells. These studies expand the paradigm for cryptococcal disease susceptibility to include a prominent role for immune-mediated damage and suggest a need for careful individual consideration of immune activation during therapy of cryptococcal disease in diverse hosts.
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Affiliation(s)
- Waleed Elsegeiny
- Laboratory of Clinical Immunology and Microbiology (LCIM), National Institute of Allergy and Infectious Diseases (NIAID), National Institutes of Health (NIH), Bethesda, MD, United States
| | | | - Peter R. Williamson
- Laboratory of Clinical Immunology and Microbiology (LCIM), National Institute of Allergy and Infectious Diseases (NIAID), National Institutes of Health (NIH), Bethesda, MD, United States
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20
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Campuzano A, Wormley FL. Innate Immunity against Cryptococcus, from Recognition to Elimination. J Fungi (Basel) 2018. [PMID: 29518906 PMCID: PMC5872336 DOI: 10.3390/jof4010033] [Citation(s) in RCA: 48] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
Cryptococcus species, the etiological agents of cryptococcosis, are encapsulated fungal yeasts that predominantly cause disease in immunocompromised individuals, and are responsible for 15% of AIDS-related deaths worldwide. Exposure follows the inhalation of the yeast into the lung alveoli, making it incumbent upon the pattern recognition receptors (PRRs) of pulmonary phagocytes to recognize highly conserved pathogen-associated molecular patterns (PAMPS) of fungi. The main challenges impeding the ability of pulmonary phagocytes to effectively recognize Cryptococcus include the presence of the yeast's large polysaccharide capsule, as well as other cryptococcal virulence factors that mask fungal PAMPs and help Cryptococcus evade detection and subsequent activation of the immune system. This review will highlight key phagocyte cell populations and the arsenal of PRRs present on these cells, such as the Toll-like receptors (TLRs), C-type lectin receptors, NOD-like receptors (NLRs), and soluble receptors. Additionally, we will highlight critical cryptococcal PAMPs involved in the recognition of Cryptococcus. The question remains as to which PRR-ligand interaction is necessary for the recognition, phagocytosis, and subsequent killing of Cryptococcus.
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Affiliation(s)
- Althea Campuzano
- Department of Biology, The University of Texas at San Antonio, San Antonio, TX 78249, USA.
- South Texas Center for Emerging Infectious Diseases, The University of Texas at San Antonio, San Antonio, TX 78249, USA.
| | - Floyd L Wormley
- Department of Biology, The University of Texas at San Antonio, San Antonio, TX 78249, USA.
- South Texas Center for Emerging Infectious Diseases, The University of Texas at San Antonio, San Antonio, TX 78249, USA.
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Abstract
Fungi have emerged as premier opportunistic microbes of the 21st century, having a considerable impact on human morbidity and mortality. The huge increase in incidence of these diseases is largely due to the HIV pandemic and use of immunosuppressive therapies, underscoring the importance of the immune system in defense against fungi. This article will address how the mammalian immune system recognizes and mounts a defense against medically relevant fungal species.
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22
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Sato K, Kawakami K. Recognition of Cryptococcus neoformans by Pattern Recognition Receptors and its Role in Host Defense to This Infection. Med Mycol J 2018; 58:J83-J90. [PMID: 28855484 DOI: 10.3314/mmj.17.011] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
Cryptococcus neoformans is a yeast-type opportunistic fungal pathogen with a capsule structure consisting of polysaccharides, such as glucuronoxylomannan and galactoxylomannan, and infects the lungs via an air-borne route. Most healthy individuals undergo asymptomatic infection with granulomatous lesions in the lungs caused by C. neoformans. However, immunocompromised hosts with severely impaired cellular immunity, such as those with acquired immune deficiency syndrome (AIDS), often suffer from disseminated infection into the central nervous system, leading to life-threatening meningoencephalitis. The recognition of pathogen-associated molecular patterns (PAMPs) by macrophages and dendritic cells plays an important role as the first line of host defense in the elimination of pathogens. Recently, numerous pattern recognition receptors (PRRs) that recognize these PAMPs have been identified. Also, the involvement of these PRRs, such as Toll-like receptors (TLRs), NOD-like receptors (NLRs), and C-type lectin receptors (CLRs), in cryptococcal infection has been analyzed. In particular, TLR9, NLR family pyrin domain-containing 3 (NLRP3), Dectin-2, mannose receptor (MR), and DC-SIGN have been found to recognize the DNA, cell wall components, intracellular polysaccharides, and mannoproteins, respectively. Future studies are expected to promote elucidation of the mechanisms of host immune response to C. neoformans, which will lead to the development of new vaccines and therapies for cryptococcal infection.
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Affiliation(s)
- Ko Sato
- Department of Medical Microbiology, Mycology and Immunology,Tohoku University Graduate School of Medicine.,Virus Research Center, Clinical Research Division, Sendai Medical Center
| | - Kazuyoshi Kawakami
- Department of Medical Microbiology, Mycology and Immunology,Tohoku University Graduate School of Medicine
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23
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Tang J, Lin G, Langdon WY, Tao L, Zhang J. Regulation of C-Type Lectin Receptor-Mediated Antifungal Immunity. Front Immunol 2018; 9:123. [PMID: 29449845 PMCID: PMC5799234 DOI: 10.3389/fimmu.2018.00123] [Citation(s) in RCA: 61] [Impact Index Per Article: 10.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2017] [Accepted: 01/16/2018] [Indexed: 12/21/2022] Open
Abstract
Of all the pathogen recognition receptor families, C-type lectin receptor (CLR)-induced intracellular signal cascades are indispensable for the initiation and regulation of antifungal immunity. Ongoing experiments over the last decade have elicited diverse CLR functions and novel regulatory mechanisms of CLR-mediated-signaling pathways. In this review, we highlight novel insights in antifungal innate and adaptive-protective immunity mediated by CLRs and discuss the potential therapeutic strategies against fungal infection based on targeting the mediators in the host immune system.
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Affiliation(s)
- Juan Tang
- Department of Nephrology, Xiangya Hospital, Central South University, Changsha, Hunan, China
| | - Guoxin Lin
- Department of Pathology, The University of Iowa, Iowa City, IA, United States.,Department of Anesthesiology, The Third Xiangya Hospital, Central South University, Changsha, Hunan, China
| | - Wallace Y Langdon
- School of Biological Sciences, University of Western Australia, Perth, WA, Australia
| | - Lijian Tao
- Department of Nephrology, Xiangya Hospital, Central South University, Changsha, Hunan, China
| | - Jian Zhang
- Department of Pathology, The University of Iowa, Iowa City, IA, United States
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24
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Ravi Kumar S, Paudel S, Ghimire L, Bergeron S, Cai S, Zemans RL, Downey GP, Jeyaseelan S. Emerging Roles of Inflammasomes in Acute Pneumonia. Am J Respir Crit Care Med 2018; 197:160-171. [PMID: 28930487 PMCID: PMC5768907 DOI: 10.1164/rccm.201707-1391pp] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2017] [Accepted: 09/19/2017] [Indexed: 12/11/2022] Open
Affiliation(s)
- Sangeetha Ravi Kumar
- Department of Pathobiological Sciences, School of Veterinary Medicine, Louisiana State University, Baton Rouge, Louisiana
| | - Sagar Paudel
- Department of Pathobiological Sciences, School of Veterinary Medicine, Louisiana State University, Baton Rouge, Louisiana
| | - Laxman Ghimire
- Department of Pathobiological Sciences, School of Veterinary Medicine, Louisiana State University, Baton Rouge, Louisiana
| | - Scott Bergeron
- Department of Pathobiological Sciences, School of Veterinary Medicine, Louisiana State University, Baton Rouge, Louisiana
| | - Shanshan Cai
- Department of Pathobiological Sciences, School of Veterinary Medicine, Louisiana State University, Baton Rouge, Louisiana
| | - Rachel L. Zemans
- Division of Pulmonary, Sleep, and Critical Care Medicine, Department of Medicine, National Jewish Health, Denver, Colorado
- Division of Pulmonary Sciences and Critical Care Medicine, University of Colorado, Denver, Aurora, Colorado; and
| | - Gregory P. Downey
- Division of Pulmonary, Sleep, and Critical Care Medicine, Department of Medicine, National Jewish Health, Denver, Colorado
- Division of Pulmonary Sciences and Critical Care Medicine, University of Colorado, Denver, Aurora, Colorado; and
| | - Samithamby Jeyaseelan
- Department of Pathobiological Sciences, School of Veterinary Medicine, Louisiana State University, Baton Rouge, Louisiana
- Section of Pulmonary and Critical Care Medicine, Department of Medicine, Louisiana State University Health Sciences Center, New Orleans, Louisiana
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25
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de Castro RJA, Siqueira IM, Jerônimo MS, Basso AMM, Veloso Junior PHDH, Magalhães KG, Leonhardt LC, de Oliveira SAM, Bürgel PH, Tavares AH, Bocca AL. The Major Chromoblastomycosis Etiologic Agent Fonsecaea pedrosoi Activates the NLRP3 Inflammasome. Front Immunol 2017; 8:1572. [PMID: 29209318 PMCID: PMC5702042 DOI: 10.3389/fimmu.2017.01572] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2017] [Accepted: 11/01/2017] [Indexed: 12/20/2022] Open
Abstract
Fonsecaea pedrosoi is the main etiologic agent of chromoblastomycosis (CBM), one of the most prevalent subcutaneous mycosis in tropical and subtropical countries. CBM is a poorly characterized chronic infection that commonly starts after transcutaneous inoculation of conidia and saprophytic hyphae of F. pedrosoi. Recently, we have shown that unlike conidia, hyphae and muriform cells (the parasitic morphotype) of F. pedrosoi promotes an intense inflammatory response pattern in vivo, which comprises the production of an inflammasome-derived cytokine, IL-1β. Nonetheless, the mechanisms underlying IL-1β production and maturation upon F. pedrosoi infection and its functional output in the course of CBM remains unknown. We show here that F. pedrosoi hyphae, differently from conidia, induce IL-1β secretion in both bone marrow-derived dendritic cells and macrophages. Using inhibitors and knockout cells, we demonstrated that the mechanisms underlying IL-1β production by hyphae-infected macrophages were dependent on dectin-1, -2, and -3 receptors and the Syk-NF-kB signaling pathway. Furthermore, F. pedrosoi promoted a NLRP3-dependent inflammasome activation, which required potassium efflux, reactive oxygen species production, phagolysosomal acidification, and cathepsin B release as triggers. IL-1β processing and release was mediated primarily by caspase-1 and, to a lesser extent, by caspase-8-dependent cleavage. Finally, we showed using a murine CBM model that F. pedrosoi elicits a NLRP3-regulated IL-1β and interleukin-18 release in vivo, but without NLRP3 inflammasome activation interfering in the course of the experimental infection.
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Affiliation(s)
- Raffael Júnio Araújo de Castro
- Laboratory of Applied Immunology, Department of Cellular Biology, Institute of Biological Sciences, University of Brasília, Brasília, Brazil
| | - Isaque Medeiros Siqueira
- Laboratory of Applied Immunology, Department of Cellular Biology, Institute of Biological Sciences, University of Brasília, Brasília, Brazil
| | - Márcio Sousa Jerônimo
- Laboratory of Applied Immunology, Department of Cellular Biology, Institute of Biological Sciences, University of Brasília, Brasília, Brazil
| | - Angelina Maria Moreschi Basso
- Laboratory of Applied Immunology, Department of Cellular Biology, Institute of Biological Sciences, University of Brasília, Brasília, Brazil
| | | | - Kelly Grace Magalhães
- Laboratory of Immunology and Inflammation, Department of Cellular Biology, Institute of Biological Sciences, University of Brasília, Brasília, Brazil
| | - Luiza Chaves Leonhardt
- Laboratory of Applied Immunology, Department of Cellular Biology, Institute of Biological Sciences, University of Brasília, Brasília, Brazil
| | - Stephan Alberto Machado de Oliveira
- Laboratory of Applied Immunology, Department of Cellular Biology, Institute of Biological Sciences, University of Brasília, Brasília, Brazil
| | - Pedro Henrique Bürgel
- Laboratory of Applied Immunology, Department of Cellular Biology, Institute of Biological Sciences, University of Brasília, Brasília, Brazil
| | - Aldo Henrique Tavares
- Laboratory of Applied Immunology, Department of Cellular Biology, Institute of Biological Sciences, University of Brasília, Brasília, Brazil
| | - Anamélia Lorenzetti Bocca
- Laboratory of Applied Immunology, Department of Cellular Biology, Institute of Biological Sciences, University of Brasília, Brasília, Brazil
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26
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Chang TH, Huang JH, Lin HC, Chen WY, Lee YH, Hsu LC, Netea MG, Ting JPY, Wu-Hsieh BA. Dectin-2 is a primary receptor for NLRP3 inflammasome activation in dendritic cell response to Histoplasma capsulatum. PLoS Pathog 2017; 13:e1006485. [PMID: 28671985 PMCID: PMC5510910 DOI: 10.1371/journal.ppat.1006485] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2017] [Revised: 07/14/2017] [Accepted: 06/21/2017] [Indexed: 11/18/2022] Open
Abstract
Inflammasome is an intracellular protein complex that serves as cytosolic pattern recognition receptor (PRR) to engage with pathogens and to process cytokines of the interleukin-1 (IL-1) family into bioactive molecules. It has been established that interleukin-1β (IL-1β) is important to host defense against Histoplasma capsulatum infection. However, the detailed mechanism of how H. capsulatum induces inflammasome activation leading to IL-1β production has not been studied. Here, we showed in dendritic cells (DCs) that H. capsulatum triggers caspase-1 activation and IL-1β production through NLRP3 inflammasome. By reciprocal blocking of Dectin-1 or Dectin-2 in single receptor-deficient DCs and cells from Clec4n-/-, Clec7a-/-, and Clec7a-/-Clec4n-/- mice, we discovered that while Dectin-2 operates as a primary receptor, Dectin-1 serves as a secondary one for NLRP3 inflammasome. In addition, both receptors trigger Syk-JNK signal pathway to activate signal 1 (pro-IL-1β synthesis) and signal 2 (activation of caspase-1). Results of pulmonary infection with H. capsulatum showed that CD103+ DCs are one of the major producers of IL-1β and Dectin-2 and Dectin-1 double deficiency abolishes their IL-1β response to the fungus. While K+ efflux and cathepsin B (but not ROS) function as signal 2, viable but not heat-killed H. capsulatum triggers profound lysosomal rupture leading to cathepsin B release. Interestingly, cathepsin B release is regulated by ERK/JNK downstream of Dectin-2 and Dectin-1. Our study demonstrates for the first time the unique roles of Dectin-2 and Dectin-1 in triggering Syk-JNK to activate signal 1 and 2 for H. capsulatum-induced NLRP3 inflammasome activation.
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Affiliation(s)
- Tzu-Hsuan Chang
- Graduate Institute of Immunology, National Taiwan University College of Medicine, Taipei, Taiwan
| | - Juin-Hua Huang
- Graduate Institute of Immunology, National Taiwan University College of Medicine, Taipei, Taiwan
| | - Hsiu-Chao Lin
- Graduate Institute of Immunology, National Taiwan University College of Medicine, Taipei, Taiwan
| | - Wen-Yu Chen
- Graduate Institute of Immunology, National Taiwan University College of Medicine, Taipei, Taiwan
| | - Yu-Hsiang Lee
- Graduate Institute of Immunology, National Taiwan University College of Medicine, Taipei, Taiwan
| | - Li-Chung Hsu
- Graduate Institute of Molecular Medicine, National Taiwan University College of Medicine, Taipei, Taiwan
| | - Mihai G. Netea
- Department of Internal Medicine and Radboud Center for Infectious Diseases, Radboud University Medical Center, Nijmegen, The Netherlands
| | - Jenny P.-Y. Ting
- Department of Microbiology and Immunology, University of North Carolina, Chapel Hill, North Carolina, United States of America
- Lineberger Comprehensive Cancer Center, University of North Carolina, Chapel Hill, North Carolina, United States of America
| | - Betty A. Wu-Hsieh
- Graduate Institute of Immunology, National Taiwan University College of Medicine, Taipei, Taiwan
- * E-mail:
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27
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Abstract
Cryptococcus species are encapsulated fungi found in the environment that predominantly cause disease in immunocompromised hosts after inhalation into the lungs. Even with contemporary antifungal regimens, patients with cryptococcosis continue to have high morbidity and mortality rates. The development of more effective therapies may depend on our understanding of the cellular and molecular mechanisms by which the host promotes sterilizing immunity against the fungus. This review will highlight our current knowledge of how Cryptococcus, primarily the species C. neoformans, is sensed by the mammalian host and how subsequent signaling pathways direct the anti-cryptococcal response by effector cells of the innate immune system.
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Affiliation(s)
- Lena J Heung
- Infectious Diseases Service, Department of Medicine, Memorial Sloan Kettering Cancer Center, New York, NY 10065, USA
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28
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Gonçalves AC, Ferreira LS, Manente FA, de Faria CMQG, Polesi MC, de Andrade CR, Zamboni DS, Carlos IZ. The NLRP3 inflammasome contributes to host protection during Sporothrix schenckii infection. Immunology 2017; 151:154-166. [PMID: 28140444 DOI: 10.1111/imm.12719] [Citation(s) in RCA: 38] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2016] [Revised: 01/18/2017] [Accepted: 01/23/2017] [Indexed: 02/06/2023] Open
Abstract
Sporotrichosis is a mycosis caused by fungi from the Sporothrix schenckii species complex, whose prototypical member is Sporothrix schenckii sensu stricto. Pattern recognition receptors (PRRs) recognize and respond to pathogen-associated molecular patterns (PAMPs) and shape the following adaptive immune response. A family of PRRs most frequently associated with fungal recognition is the nucleotide-binding oligomerization domain-like receptor (NLR). After PAMP recognition, NLR family pyrin domain-containing 3 (NLRP3) binds to apoptosis-associated speck-like protein containing a caspase recruitment domain (ASC) and caspase-1 to form the NLRP3 inflammasome. When activated, this complex promotes the maturation of the pro-inflammatory cytokines interleukin-1β (IL-1β) and IL-18 and cell death through pyroptosis. In this study, we aimed to evaluate the importance of the NLRP3 inflammasome in the outcome of S. schenckii infection using the following three different knockout (KO) mice: NLRP3-/- , ASC-/- and caspase-1-/- . All KO mice were more susceptible to infection than the wild-type, suggesting that NLRP3-triggered responses contribute to host protection during S. schenckii infection. Furthermore, the NLRP3 inflammasome appeared to be critical for the ex vivo release of IL-1β, IL-18 and IL-17 but not interferon-γ. Additionally, a role for the inflammasome in shaping the adaptive immune response was suggested by the lower frequencies of type 17 helper T (Th17) cells and Th1/Th17 but not Th1 cells in S. schenckii-infected KO mice. Overall, our results indicate that the NLRP3 inflammasome links the innate recognition of S. schenckii to the adaptive immune response, so contributing to protection against this infection.
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Affiliation(s)
- Amanda Costa Gonçalves
- Department of Clinical Analysis, Faculty of Pharmaceutical Sciences of Araraquara, São Paulo State University (FCF/UNESP), Araraquara, Brazil
| | - Lucas Souza Ferreira
- Department of Clinical Analysis, Faculty of Pharmaceutical Sciences of Araraquara, São Paulo State University (FCF/UNESP), Araraquara, Brazil
| | - Francine Alessandra Manente
- Department of Clinical Analysis, Faculty of Pharmaceutical Sciences of Araraquara, São Paulo State University (FCF/UNESP), Araraquara, Brazil
| | | | - Marisa Campos Polesi
- Department of Clinical Analysis, Faculty of Pharmaceutical Sciences of Araraquara, São Paulo State University (FCF/UNESP), Araraquara, Brazil
| | - Cleverton Roberto de Andrade
- Department of Physiology and Pathology, Faculty of Dentistry of Araraquara, São Paulo State University (FOAR/UNESP), Araraquara, Brazil
| | - Dario Simões Zamboni
- Department of Cell Biology, Ribeirão Preto Medical School, University of São Paulo (FMRP/USP), Ribeirão Preto, Brazil
| | - Iracilda Zeppone Carlos
- Department of Clinical Analysis, Faculty of Pharmaceutical Sciences of Araraquara, São Paulo State University (FCF/UNESP), Araraquara, Brazil
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Rim Pathway-Mediated Alterations in the Fungal Cell Wall Influence Immune Recognition and Inflammation. mBio 2017; 8:mBio.02290-16. [PMID: 28143983 PMCID: PMC5285508 DOI: 10.1128/mbio.02290-16] [Citation(s) in RCA: 38] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023] Open
Abstract
Compared to other fungal pathogens, Cryptococcus neoformans is particularly adept at avoiding detection by innate immune cells. To explore fungal cellular features involved in immune avoidance, we characterized cell surface changes of the C. neoformans rim101Δ mutant, a strain that fails to organize and shield immunogenic epitopes from host detection. These cell surface changes are associated with an exaggerated, detrimental inflammatory response in mouse models of infection. We determined that the disorganized strain rim101Δ cell wall increases macrophage detection in a contact-dependent manner. Using biochemical and microscopy methods, we demonstrated that the rim101Δ strain shows a modest increase in the levels of both cell wall chitin and chitosan but that it shows a more dramatic increase in chito-oligomer exposure, as measured by wheat germ agglutinin staining. We also created a series of mutants with various levels of cell wall wheat germ agglutinin staining, and we demonstrated that the staining intensity correlates with the degree of macrophage activation in response to each strain. To explore the host receptors responsible for recognizing the rim101Δ mutant, we determined that both the MyD88 and CARD9 innate immune signaling proteins are involved. Finally, we characterized the immune response to the rim101Δ mutant in vivo, documenting a dramatic and sustained increase in Th1 and Th17 cytokine responses. These results suggest that the Rim101 transcription factor actively regulates the C. neoformans cell wall to prevent the exposure of immune stimulatory molecules within the host. These studies further explored the ways in which immune cells detect C. neoformans and other fungal pathogens by mechanisms that include sensing N-acetylglucosamine-containing structures, such as chitin and chitosan. Infectious microorganisms have developed many ways to avoid recognition by the host immune system. For example, pathogenic fungi alter their cell surfaces to mask immunogenic epitopes. We have created a fungal strain with a targeted mutation in a pH response pathway that is unable to properly organize its cell wall, resulting in a dramatic immune reaction during infection. This mutant cell wall is defective in hiding important cell wall components, such as the chito-oligomers chitin and chitosan. By creating a series of cell wall mutants, we demonstrated that the degree of chito-oligomer exposure correlates with the intensity of innate immune cell activation. This activation requires a combination of host receptors to recognize and respond to these infecting microorganisms. Therefore, these experiments explored host-pathogen interactions that determine the degree of the subsequent inflammatory response and the likely outcome of infection.
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Induction of Protective Immunity to Cryptococcal Infection in Mice by a Heat-Killed, Chitosan-Deficient Strain of Cryptococcus neoformans. mBio 2016; 7:mBio.00547-16. [PMID: 27165801 PMCID: PMC4959652 DOI: 10.1128/mbio.00547-16] [Citation(s) in RCA: 64] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
Cryptococcus neoformans is a major opportunistic fungal pathogen that causes fatal meningoencephalitis in immunocompromised individuals and is responsible for a large proportion of AIDS-related deaths. The fungal cell wall is an essential organelle which undergoes constant modification during various stages of growth and is critical for fungal pathogenesis. One critical component of the fungal cell wall is chitin, which in C. neoformans is predominantly deacetylated to chitosan. We previously reported that three chitin deacetylase (CDA) genes have to be deleted to generate a chitosan-deficient C. neoformans strain. This cda1Δ2Δ3Δ strain was avirulent in mice, as it was rapidly cleared from the lungs of infected mice. Here, we report that clearance of the cda1Δ2Δ3Δ strain was associated with sharply spiked concentrations of proinflammatory molecules that are known to be critical mediators of the orchestration of a protective Th1-type adaptive immune response. This was followed by the selective enrichment of the Th1-type T cell population in the cda1Δ2Δ3Δ strain-infected mouse lung. Importantly, this response resulted in the development of robust protective immunity to a subsequent lethal challenge with a virulent wild-type C. neoformans strain. Moreover, protective immunity was also induced in mice vaccinated with heat-killed cda1Δ2Δ3Δ cells and was effective in multiple mouse strains. The results presented here provide a strong framework to develop the cda1Δ2Δ3Δ strain as a potential vaccine candidate for C. neoformans infection. The most commonly used anticryptococcal therapies include amphotericin B, 5-fluorocytosine, and fluconazole alone or in combination. Major drawbacks of these treatment options are their limited efficacy, poor availability in limited resource areas, and potential toxicity. The development of antifungal vaccines and immune-based therapeutic interventions is promising and an attractive alternative to chemotherapeutics. Currently, there are no fungal vaccines in clinical use. This is the first report of a C. neoformans deletion strain with an avirulent phenotype in mice exhibiting protective immunity when used as a vaccine after heat inactivation, although other strains that overexpress fungal or murine proteins have recently been shown to induce a protective response. The data presented here demonstrate the potential for developing the avirulent cda1Δ2Δ3Δ strain into a vaccine-based therapy to treat C. neoformans infection.
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van de Veerdonk FL, Joosten LAB, Netea MG. The interplay between inflammasome activation and antifungal host defense. Immunol Rev 2016; 265:172-80. [PMID: 25879292 DOI: 10.1111/imr.12280] [Citation(s) in RCA: 39] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
Fungal infections cause significant morbidity and mortality in humans, and they are a growing problem due to the increased usage of broad-spectrum antibiotics and immunosuppressive therapies. The equilibrium between the commensal microbial flora and the immune system that protects the host against invasive fungal infection is disturbed during disease, and understanding this disturbed balance is important to develop new therapeutic interventions for the treatment of fungal infection. In the context of tolerating fungi during colonization and eliciting a vigorous immune response to eliminate invading fungal pathogens when needed, the inflammasome has been identified as an integral component of antifungal host defense. It contributes to mucosal host defense by regulating T-helper 17 (Th17) cell responses, and contributes to protective responses such as neutrophil influx during fungal sepsis. Several aspects are important for understanding the role of the inflammasome for antifungal host defense, such as the role of fungal cell wall morphology and its components in triggering the inflammasome, the pattern recognition pathways and downstream signaling cascades involved in the activation of the inflammasome, and the effects of inflammasome activation during fungal infection. The future perspectives of inflammasome research in fungal immunology, with emphasis on targeting the inflammasome for the design of future immunotherapies, is also discussed.
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Affiliation(s)
- Frank L van de Veerdonk
- Department of Internal Medicine, Radboud University Medical Center, Nijmegen, The Netherlands; Radboud Center for Infectious Diseases, Radboud University Medical Center, Nijmegen, The Netherlands
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Abstract
The complementary actions of the innate and adaptive immune systems often provide effective host defense against microbial pathogens and harmful environmental agents. Germline-encoded pattern recognition receptors (PRRs) endow the innate immune system with the ability to detect and mount a rapid response against a given threat. Members of several intracellular PRR families, including the nucleotide-binding domain and leucine-rich repeat containing receptors (NLRs), the AIM2-like receptors (ALRs), and the tripartite motif-containing (TRIM) protein Pyrin/TRIM20, nucleate the formation of inflammasomes. These cytosolic scaffolds serve to recruit and oligomerize the cysteine protease caspase-1 in filaments that promote its proximity-induced autoactivation. This oligomerization occurs either directly or indirectly through intervention of the bipartite adaptor protein ASC, apoptosis-associated speck-like protein containing a caspase recruitment domain (CARD), which is needed for the domain interaction. Caspase-1 cleaves the precursors of the inflammatory cytokines interleukin (IL)-1β and IL-18 and triggers their release into the extracellular space, where they act on effector cells to promote both local and systemic immune responses. Additionally, inflammasome activation gives rise to a lytic mode of cell death, named pyroptosis, which is thought to contribute to initial host defense against infection by eliminating replication niches of intracellular pathogens and exposing them to the immune system. Inflammasome-induced host defense responses are the subject of intense investigation, and understanding their physiological roles during infection and the regulatory circuits that are involved is becoming increasingly detailed. Here, we discuss current understanding of the activation mechanisms and biological outcomes of inflammasome activation.
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Affiliation(s)
- Hanne Dubois
- NOD-like Receptor and Inflammasome Laboratory, Inflammation Research Center, VIB, 9052, Zwijnaarde, Belgium.,Department of Internal Medicine, Ghent University, 9000, Ghent, Belgium
| | - Andy Wullaert
- NOD-like Receptor and Inflammasome Laboratory, Inflammation Research Center, VIB, 9052, Zwijnaarde, Belgium.,Department of Internal Medicine, Ghent University, 9000, Ghent, Belgium
| | - Mohamed Lamkanfi
- NOD-like Receptor and Inflammasome Laboratory, Inflammation Research Center, VIB, 9052, Zwijnaarde, Belgium. .,Department of Internal Medicine, Ghent University, 9000, Ghent, Belgium.
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Abstract
Intracellular inflammasome complexes regulate critical cytokine responses to infections. In this issue of Cell Host & Microbe,Karki et al. (2015) show that protection against the fungus Aspergillus requires the combined efforts of the NLRP3 and AIM2 inflammasomes and involves both caspase-1 and caspase-8.
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Affiliation(s)
- Jeffrey Tomalka
- Department of Pathology, Case Western Reserve University School of Medicine, Cleveland, OH 44106, USA
| | - Amy G Hise
- Department of Pathology, Case Western Reserve University School of Medicine, Cleveland, OH 44106, USA; Geriatric Research Education and Clinical Center, Louis Stokes Cleveland Department of Veterans Affairs Medical Center, Cleveland, OH 44106, USA; Center for Global Health and Diseases, Case Western Reserve University School of Medicine, Cleveland, OH 44106, USA.
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Park YD, Williamson PR. Masking the Pathogen: Evolutionary Strategies of Fungi and Their Bacterial Counterparts. J Fungi (Basel) 2015; 1:397-421. [PMID: 29376918 PMCID: PMC5753132 DOI: 10.3390/jof1030397] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2015] [Revised: 12/03/2015] [Accepted: 12/07/2015] [Indexed: 11/21/2022] Open
Abstract
Pathogens reduce immune recognition of their cell surfaces using a variety of inert structural polysaccharides. For example, capsular polysaccharides play critical roles in microbial survival strategies. Capsules are widely distributed among bacterial species, but relatively rare in eukaryotic microorganisms, where they have evolved considerable complexity in structure and regulation and are exemplified by that of the HIV/AIDS-related fungus Cryptococcus neoformans. Endemic fungi that affect normal hosts such as Histoplasma capsulatum and Blastomyces dermatitidis have also evolved protective polysaccharide coverings in the form of immunologically inert α-(1,3)-glucan polysaccharides to protect their more immunogenic β-(1,3)-glucan-containing cell walls. In this review we provide a comparative update on bacterial and fungal capsular structures and immunogenic properties as well as the polysaccharide masking strategies of endemic fungal pathogens.
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Affiliation(s)
- Yoon-Dong Park
- Laboratory of Clinical Infectious Diseases, National Institute of Allergy and Infectious Diseases, National Institutes of Health, 9000 Rockville Pike, Building 10, Rm 11N222, MSC 1888, Bethesda, MD 20892, USA.
| | - Peter R Williamson
- Laboratory of Clinical Infectious Diseases, National Institute of Allergy and Infectious Diseases, National Institutes of Health, 9000 Rockville Pike, Building 10, Rm 11N222, MSC 1888, Bethesda, MD 20892, USA.
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Chen M, Xing Y, Lu A, Fang W, Sun B, Chen C, Liao W, Meng G. Internalized Cryptococcus neoformans Activates the Canonical Caspase-1 and the Noncanonical Caspase-8 Inflammasomes. THE JOURNAL OF IMMUNOLOGY 2015; 195:4962-72. [PMID: 26466953 DOI: 10.4049/jimmunol.1500865] [Citation(s) in RCA: 54] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/13/2015] [Accepted: 09/18/2015] [Indexed: 12/15/2022]
Abstract
Cryptococcus neoformans is an opportunistic fungal pathogen that causes cryptococcosis in immunocompromised patients as well as immunocompetent individuals. Host cell surface receptors that recognize C. neoformans have been widely studied. However, intracellular sensing of this pathogen is still poorly understood. Our previous studies have demonstrated that both biofilm and acapsular mutant of C. neoformans are able to activate the NOD-like receptor family, pyrin domain-containing 3 (NLRP3) inflammasome. In the current study, it was found that opsonization-mediated internalization of encapsulated C. neoformans also activated the canonical NLRP3-apoptosis-associated speck-like protein containing a CARD (ASC)-caspase-1 inflammasome. In addition, the internalized C. neoformans activated the noncanonical NLRP3-ASC-caspase-8 inflammasome as well, which resulted in robust IL-1β secretion and cell death from caspase-1-deficient primary dendritic cells. Interestingly, we found that caspase-1 was inhibitory for the activation of caspase-8 in dendritic cells upon C. neorformans challenge. Further mechanistic studies showed that both phagolysosome membrane permeabilization and potassium efflux were responsible for C. neoformans-induced activation of either the canonical NLRP3-ASC-caspase-1 inflammasome or the noncanonical NLRP3-ASC-caspase-8 inflammasome. Moreover, challenge with zymosan also led to the activation of the noncanonical NLRP3-ASC-caspase-8 inflammasome in cells absent for caspase-1. Collectively, these findings uncover a number of novel signaling pathways for the innate immune response of host cells to C. neoformans infection and suggest that manipulating NLRP3 signaling may help to control fungal challenge.
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Affiliation(s)
- Mingkuan Chen
- Key Laboratory of Molecular Virology and Immunology, Institut Pasteur of Shanghai, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai 200031, China; and
| | - Yue Xing
- Key Laboratory of Molecular Virology and Immunology, Institut Pasteur of Shanghai, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai 200031, China; and
| | - Ailing Lu
- Key Laboratory of Molecular Virology and Immunology, Institut Pasteur of Shanghai, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai 200031, China; and
| | - Wei Fang
- Shanghai Key Laboratory of Molecular Medical Mycology, Changzheng Hospital, Shanghai 200003, China
| | - Bing Sun
- Key Laboratory of Molecular Virology and Immunology, Institut Pasteur of Shanghai, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai 200031, China; and
| | - Changbin Chen
- Key Laboratory of Molecular Virology and Immunology, Institut Pasteur of Shanghai, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai 200031, China; and
| | - Wanqing Liao
- Shanghai Key Laboratory of Molecular Medical Mycology, Changzheng Hospital, Shanghai 200003, China
| | - Guangxun Meng
- Key Laboratory of Molecular Virology and Immunology, Institut Pasteur of Shanghai, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai 200031, China; and
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Affiliation(s)
- Aldo Henrique Tavares
- Laboratório de Imunologia Aplicada, Departamento de Biologia Celular, Instituto de Biologia, Universidade de Brasília, Brasília, Distrito Federal, Brasil
- * E-mail:
| | - Pedro Henrique Bürgel
- Laboratório de Imunologia Aplicada, Departamento de Biologia Celular, Instituto de Biologia, Universidade de Brasília, Brasília, Distrito Federal, Brasil
| | - Anamélia Lorenzetti Bocca
- Laboratório de Imunologia Aplicada, Departamento de Biologia Celular, Instituto de Biologia, Universidade de Brasília, Brasília, Distrito Federal, Brasil
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O'Meara TR, Veri AO, Ketela T, Jiang B, Roemer T, Cowen LE. Global analysis of fungal morphology exposes mechanisms of host cell escape. Nat Commun 2015; 6:6741. [PMID: 25824284 PMCID: PMC4382923 DOI: 10.1038/ncomms7741] [Citation(s) in RCA: 177] [Impact Index Per Article: 19.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2014] [Accepted: 02/24/2015] [Indexed: 11/13/2022] Open
Abstract
Developmental transitions between single-cell yeast and multicellular filaments underpin virulence of diverse fungal pathogens. For the leading human fungal pathogen Candida albicans, filamentation is thought to be required for immune cell escape via induction of an inflammatory programmed cell death. Here we perform a genome-scale analysis of C. albicans morphogenesis and identify 102 negative morphogenetic regulators and 872 positive regulators, highlighting key roles for ergosterol biosynthesis and N-linked glycosylation. We demonstrate that C. albicans filamentation is not required for escape from host immune cells; instead, macrophage pyroptosis is driven by fungal cell-wall remodelling and exposure of glycosylated proteins in response to the macrophage phagosome. The capacity of killed, previously phagocytized cells to drive macrophage lysis is also observed with the distantly related fungal pathogen Cryptococcus neoformans. This study provides a global view of morphogenetic circuitry governing a key virulence trait, and illuminates a new mechanism by which fungi trigger host cell death. Several pathogenic fungi such as Candida albicans undergo transitions between single-celled forms and multicellular filaments. Here the authors perform a genome-scale analysis of C. albicans and show that, contrary to common belief, filamentation is not required for escape from host immune cells.
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Affiliation(s)
- Teresa R O'Meara
- Department of Molecular Genetics, University of Toronto, Toronto, Ontario, Canada M5S 1A8
| | - Amanda O Veri
- Department of Molecular Genetics, University of Toronto, Toronto, Ontario, Canada M5S 1A8
| | - Troy Ketela
- Department of Molecular Genetics, University of Toronto, Toronto, Ontario, Canada M5S 1A8
| | - Bo Jiang
- Bioprocess Technology &Expression, Merck Research Laboratories, 2000 Galloping Hill Rd, Kenilworth, New Jersey 07033, USA
| | - Terry Roemer
- Department of Infectious Diseases, Merck Research Laboratories, 2000 Galloping Hill Rd, Kenilworth, New Jersey 07033, USA
| | - Leah E Cowen
- Department of Molecular Genetics, University of Toronto, Toronto, Ontario, Canada M5S 1A8
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Gibson JF, Johnston SA. Immunity to Cryptococcus neoformans and C. gattii during cryptococcosis. Fungal Genet Biol 2014; 78:76-86. [PMID: 25498576 PMCID: PMC4503824 DOI: 10.1016/j.fgb.2014.11.006] [Citation(s) in RCA: 71] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2014] [Revised: 11/25/2014] [Accepted: 11/29/2014] [Indexed: 10/25/2022]
Abstract
The vast majority of infection with cryptococcal species occurs with Cryptococcus neoformans in the severely immunocompromised. A significant exception to this is the infections of those with apparently normal immune systems by Cryptococcus gattii. Susceptibility to cryptococcosis can be broadly categorised as a defect in adaptive immune responses, especially in T cell immunity. However, innate immune cells such as macrophages play a key role and are likely the primary effector cell in the killing and ultimate clearance of cryptococcal infection. In this review we discuss the current state of our understanding of how the immune system responds to cryptococcal infection in health and disease, with reference to the work communicated at the 9th International Conference on Cryptococcus and Cryptococcosis (ICCC9). We have focussed on cell mediated responses, particularly early in infection, but with the aim of presenting a broad overview of our understanding of immunity to cryptococcal infection, highlighting some recent advances and offering some perspectives on future directions.
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Affiliation(s)
- Josie F Gibson
- Department of Infection and Immunity, Medical School, University of Sheffield, S10 2RX, UK; Bateson Centre, Department of Biomedical Sciences, University of Sheffield, S10 2TN, UK
| | - Simon A Johnston
- Department of Infection and Immunity, Medical School, University of Sheffield, S10 2RX, UK; Bateson Centre, Department of Biomedical Sciences, University of Sheffield, S10 2TN, UK.
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