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Höft MA, Duvenage L, Hoving JC. Key thermally dimorphic fungal pathogens: shaping host immunity. Open Biol 2022; 12:210219. [PMID: 35259948 PMCID: PMC8905152 DOI: 10.1098/rsob.210219] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2021] [Accepted: 02/09/2022] [Indexed: 01/09/2023] Open
Abstract
Exposure to fungal pathogens from the environment is inevitable and with the number of at-risk populations increasing, the prevalence of invasive fungal infection is on the rise. An interesting group of fungal organisms known as thermally dimorphic fungi predominantly infects immunocompromised individuals. These potential pathogens are intriguing in that they survive in the environment in one form, mycelial phase, but when entering the host, they are triggered by the change in temperature to switch to a new pathogenic form. Considering the growing prevalence of infection and the need for improved diagnostic and treatment approaches, studies identifying key components of fungal recognition and the innate immune response to these pathogens will significantly contribute to our understanding of disease progression. This review focuses on key endemic dimorphic fungal pathogens that significantly contribute to disease, including Histoplasma, Coccidioides and Talaromyces species. We briefly describe their prevalence, route of infection and clinical presentation. Importantly, we have reviewed the major fungal cell wall components of these dimorphic fungi, the host pattern recognition receptors responsible for recognition and important innate immune responses supporting adaptive immunity and fungal clearance or the failure thereof.
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Affiliation(s)
- Maxine A. Höft
- CMM AFRICA Medical Mycology Research Unit, Institute of Infectious Diseases and Molecular Medicine (IDM), University of Cape Town, Cape Town 7925, South Africa
- Department of Pathology, Faculty of Health Sciences, University of Cape Town, Cape Town 7925, South Africa
- MRC Centre for Medical Mycology at the University of Exeter, Geoffrey Pope Building, Stocker Road, Exeter EX4 4QD, UK
| | - Lucian Duvenage
- CMM AFRICA Medical Mycology Research Unit, Institute of Infectious Diseases and Molecular Medicine (IDM), University of Cape Town, Cape Town 7925, South Africa
- Department of Pathology, Faculty of Health Sciences, University of Cape Town, Cape Town 7925, South Africa
- MRC Centre for Medical Mycology at the University of Exeter, Geoffrey Pope Building, Stocker Road, Exeter EX4 4QD, UK
| | - J. Claire Hoving
- CMM AFRICA Medical Mycology Research Unit, Institute of Infectious Diseases and Molecular Medicine (IDM), University of Cape Town, Cape Town 7925, South Africa
- Department of Pathology, Faculty of Health Sciences, University of Cape Town, Cape Town 7925, South Africa
- MRC Centre for Medical Mycology at the University of Exeter, Geoffrey Pope Building, Stocker Road, Exeter EX4 4QD, UK
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2
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Monocyte-Derived Dendritic Cells Can Revert In Vitro Antigen-Specific Cellular Anergy in Active Human Paracoccidioidomycosis. J Fungi (Basel) 2021; 7:jof7030201. [PMID: 33802081 PMCID: PMC8000053 DOI: 10.3390/jof7030201] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2020] [Revised: 12/30/2020] [Accepted: 01/08/2021] [Indexed: 12/03/2022] Open
Abstract
We investigated the in vitro effects of two Paracoccidioides brasiliensis antigens on monocyte-derived dendritic cells (moDCs) from patients with paracoccidioidomycosis (PCM). MoDCs from patients with active or treated PCM and non-PCM subjects were generated, stimulated with TNF-α, and P. brasiliensis antigens, 43 kDa glycoprotein (gp43) and cell-free antigen (CFA), and analyzed by flow cytometry and enzyme-linked immunosorbent assays (ELISA). Our data revealed that patients with PCM had a high frequency of HLA-DR+ cells, but the treated group had more CD86+ cells with increased IL-12p40. Patients with active PCM had more CD80+ moDCs, and as a novel finding, large amounts of chemokine (C-C motif) ligand 18 (CCL18) in the supernatants from their in vitro moDC cultures. Both gp43- and CFA-stimulated moDCs from the patients with PCM successfully reverted the in vitro antigen-specific anergy, inducing a proliferative response. However, CFA-stimulated moDCs led to higher lymphoproliferation, with increased IFN-γ and TNF-α in the cells from the patients with active PCM compared with gp43. These original results combined with constant IL-10 and increased IL-12p40 levels suggest that a more complex antigen, such as CFA, may be a better inducer of the protective Th1 immune response than purified gp43 is, and a suitable target for future studies on anti-P. brasiliensis dendritic cell (DC)-based vaccines.
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3
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Last A, Maurer M, Mosig AS, Gresnigt MS, Hube B. In vitro infection models to study fungal-host interactions. FEMS Microbiol Rev 2021; 45:6125970. [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] [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, Jena, Germany
| | - Michelle Maurer
- Center for Sepsis Control and Care (CSCC), University Hospital Jena, Jena, Germany.,Institute of Biochemistry II, Jena University Hospital, Jena, Germany
| | - Alexander S Mosig
- Center for Sepsis Control and Care (CSCC), University Hospital Jena, Jena, Germany.,Institute of Biochemistry II, Jena University Hospital, Jena, Germany
| | - Mark S Gresnigt
- Junior Research Group Adaptive Pathogenicity Strategies, Leibniz Institute for Natural Product Research and Infection Biology - Hans-Knoell-Institute, Jena, Germany
| | - Bernhard Hube
- Department of Microbial Pathogenicity Mechanisms, Leibniz Institute for Natural Product Research and Infection Biology - Hans-Knoell-Institute, Jena, Germany.,Institute of Microbiology, Friedrich Schiller University, Jena, Germany
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Kirkland TN, Fierer J. Innate Immune Receptors and Defense Against Primary Pathogenic Fungi. Vaccines (Basel) 2020; 8:E303. [PMID: 32545735 PMCID: PMC7350247 DOI: 10.3390/vaccines8020303] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2020] [Revised: 06/10/2020] [Accepted: 06/11/2020] [Indexed: 02/07/2023] Open
Abstract
The innate immune system is critical for natural resistance to all pathogenic microorganisms, including fungi. The innate response plays a vital role in resistance to infections before the antigen-specific immune response and also influences antigen-specific adaptive immunity. There are many different receptors for the innate immune response to fungi, and some receptors have been found to play a significant role in the response to human infections with opportunistic fungi. Most human infections are caused by opportunistic fungi, but a small number of organisms are capable of causing infections in normal hosts. The primary pathogenic fungi that cause invasive infections include Blastomyces spp., Cryptococcus gattii, Coccidioides spp., Histoplasma spp., and Paracoccidioides spp. In this review of innate immune receptors that play a role in infections caused by these organisms, we find that innate immunity differs between organisms.
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Affiliation(s)
- Theo N. Kirkland
- Division of Infectious Diseases, Departments of Pathology and Medicine, School of Medicine, University of California San Diego, San Diego, CA 92037, USA;
| | - Joshua Fierer
- Division of Infectious Diseases, Departments of Pathology and Medicine, School of Medicine, University of California San Diego, San Diego, CA 92037, USA;
- VA HealthCare San Diego, San Diego, CA 92161, USA
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Thompson‐Souza GA, Santos GMP, Silva JC, Muniz VS, Braga YAV, Figueiredo RT, Melo RCN, Santos ALS, Pinto MR, Neves JS. Histoplasma capsulatum
‐induced extracellular DNA trap release in human neutrophils. Cell Microbiol 2020; 22:e13195. [DOI: 10.1111/cmi.13195] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2019] [Revised: 02/12/2020] [Accepted: 02/13/2020] [Indexed: 01/08/2023]
Affiliation(s)
| | | | - Juliana C. Silva
- Institute of Biomedical Sciences/Institute of Microbiology Paulo de GóesFederal University of Rio de Janeiro Rio de Janeiro Brazil
| | - Valdirene S. Muniz
- Institute of Biomedical SciencesFederal University of Rio de Janeiro Rio de Janeiro Brazil
| | - Yasmim A. V. Braga
- Institute of Biomedical Sciences/Institute of Microbiology Paulo de GóesFederal University of Rio de Janeiro Rio de Janeiro Brazil
| | - Rodrigo T. Figueiredo
- Institute of Biomedical Sciences/Campus of Duque de CaxiasFederal University of Rio de Janeiro Rio de Janeiro Brazil
| | - Rossana C. N. Melo
- Laboratory of Cellular Biology, Department of Biology, Institute of Biological SciencesFederal University of Juiz de Fora Juiz de Fora Brazil
| | - André L. S. Santos
- Institute of Microbiology Paulo de GóesFederal University of Rio de Janeiro Rio de Janeiro Brazil
| | - Marcia R. Pinto
- Biomedical InstituteFluminense Federal University Niterói Brazil
| | - Josiane S. Neves
- Institute of Biomedical SciencesFederal University of Rio de Janeiro Rio de Janeiro Brazil
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Ray SC, Rappleye CA. Flying under the radar: Histoplasma capsulatum avoidance of innate immune recognition. Semin Cell Dev Biol 2019; 89:91-98. [PMID: 29551572 PMCID: PMC6150853 DOI: 10.1016/j.semcdb.2018.03.009] [Citation(s) in RCA: 29] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2017] [Accepted: 03/14/2018] [Indexed: 10/17/2022]
Abstract
The dimorphic fungal pathogen Histoplasma capsulatum takes advantage of the innate immune system, utilizing host macrophages as a proliferative niche while largely avoiding stimulation of signaling host receptors. As a result, innate immune cells are unable to control H. capsulatum on their own. Not all host phagocytes respond to H. capsulatum in the same way, with neutrophils and dendritic cells playing important roles in impeding fungal growth and initiating a protective TH1 response, respectively. Dendritic cells prime T-cell differentiation after internalization of yeasts via VLA-5 receptors and subsequent degradation of the yeasts. Dendritic cell-expressed TLR7 and TLR9 promote a type I interferon response for TH1 polarization. In contrast to dendritic cells, macrophages provide a hospitable intracellular environment. H. capsulatum yeasts enter macrophages via binding to phagocytic receptors. Simultaneously, α-glucan masks immunostimulatory cell wall β-glucans and a secreted endoglucanase removes exposed β-glucans to minimize recognition of yeasts by Dectin-1. This review highlights how phagocytes interact with H. capsulatum yeasts and the mechanisms H. capsulatum uses to limit the innate immune response.
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Issac JM, Mohamed YA, Bashir GH, Al-Sbiei A, Conca W, Khan TA, Iqbal A, Riemekasten G, Bieber K, Ludwig RJ, Cabral-Marques O, Fernandez-Cabezudo MJ, Al-Ramadi BK. Induction of Hypergammaglobulinemia and Autoantibodies by Salmonella Infection in MyD88-Deficient Mice. Front Immunol 2018; 9:1384. [PMID: 29973931 PMCID: PMC6019449 DOI: 10.3389/fimmu.2018.01384] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2017] [Accepted: 06/04/2018] [Indexed: 12/14/2022] Open
Abstract
Growing evidence indicates a link between persistent infections and the development of autoimmune diseases. For instance, the inability to control Salmonella infection due to defective toll-like receptor (TLR)/myeloid differentiation primary response 88 (MyD88) signaling has linked the development of persistent infections to a breakdown in B cell tolerance. However, the extent of immune dysregulation in the absence of TLR-MyD88 signaling remains poorly characterized. Here, we show that MyD88−/− mice are unable to eliminate attenuated Salmonella enterica serovar Typhimurium, even when challenged with a low-dose inoculum (200 CFUs/mouse), developing a persistent and progressive infection when compared to wild-type (MyD88+/+) animals. The splenic niche of MyD88−/− mice revealed increased counts of activated, Sca-1-positive, myeloid subpopulations highly expressing BAFF during persistent Salmonella infection. Likewise, the T cell compartment of Salmonella-infected MyD88−/− mice showed increased levels of CD4+ and CD8+ T cells expressing Sca-1 and CD25 and producing elevated amounts of IL-4, IL-10, and IL-21 in response to CD3/CD28 stimulation. This was associated with increased Tfh cell differentiation and the presence of CD4+ T cells co-expressing IFN-γ/IL-4 and IFN-γ/IL-10. Noteworthy, infected MyD88−/− mice had enhanced serum titers of both anti-Salmonella antibodies as well as autoantibodies directed against double-stranded DNA, thyroglobulin, and IgG rheumatoid factor, positive nuclear staining with HEp-2 cells, and immune complex deposition in the kidneys of MyD88−/− mice infected with live but not heat-killed Salmonella. Infection with other microorganisms (Acinetobacter baumanii, Streptococcus agalactiae, or Escherichia coli) was unable to trigger the autoimmune phenomenon. Our findings suggest that dysregulation of the immune response in the absence of MyD88 is pathogen-dependent and highlight potentially important genotype–environmental factor correlations.
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Affiliation(s)
- Jincy M Issac
- Department of Medical Microbiology and Immunology, College of Medicine and Health Sciences, United Arab Emirates University, Al Ain, United Arab Emirates
| | - Yassir A Mohamed
- Department of Medical Microbiology and Immunology, College of Medicine and Health Sciences, United Arab Emirates University, Al Ain, United Arab Emirates
| | - Ghada Hassan Bashir
- Department of Medical Microbiology and Immunology, College of Medicine and Health Sciences, United Arab Emirates University, Al Ain, United Arab Emirates
| | - Ashraf Al-Sbiei
- Department of Biochemistry, College of Medicine and Health Sciences, United Arab Emirates University, Al Ain, United Arab Emirates
| | - Walter Conca
- Department of Internal Medicine, College of Medicine and Health Sciences, United Arab Emirates University, Al Ain, United Arab Emirates
| | - Taj A Khan
- Department of Microbiology, Kohat University of Science and Technology, Kohat, Pakistan
| | - Asif Iqbal
- Department of Pharmacology, University of Illinois at Chicago, Chicago, IL, United States
| | | | - Katja Bieber
- Lübeck Institute of Experimental Dermatology, University of Lübeck, Lübeck, Germany
| | - Ralf J Ludwig
- Lübeck Institute of Experimental Dermatology, University of Lübeck, Lübeck, Germany
| | | | - Maria J Fernandez-Cabezudo
- Department of Biochemistry, College of Medicine and Health Sciences, United Arab Emirates University, Al Ain, United Arab Emirates
| | - Basel K Al-Ramadi
- Department of Medical Microbiology and Immunology, College of Medicine and Health Sciences, United Arab Emirates University, Al Ain, United Arab Emirates
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Myeloid Differentiation Factor 88 and Interleukin-1R1 Signaling Contribute to Resistance to Coccidioides immitis. Infect Immun 2018; 86:IAI.00028-18. [PMID: 29610256 DOI: 10.1128/iai.00028-18] [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] [Received: 03/26/2018] [Accepted: 03/26/2018] [Indexed: 12/21/2022] Open
Abstract
Rodents are a natural host for the dimorphic pathogenic fungi Coccidioides immitis and Coccidioides posadasii, and mice are a good model for human infection. Humans and rodents both express Dectin-1 and Toll-like receptor 2 (TLR2) on myeloid cells, and those receptors collaborate to maximize the cytokine/chemokine responses to spherules (the tissue form of the fungi) and to formalin-killed spherules (FKS). We showed that Dectin-1 is necessary for resistance to pulmonary coccidioidomycosis, but the importance of TLR2 in vivo is uncertain. Myeloid differentiation factor 88 (MyD88) is the adapter protein for TLR2 and -4, interleukin-1R1 (IL-1R1), and IL-18R1. MyD88/TRIF-/- and MyD88-/- mice were equally susceptible to C. immitis infection, in contrast to C57BL/6 (B6) controls. Of the four surface receptors, only IL-1R1 was required for resistance to C. immitis, partially explaining the susceptibility of MyD88-/- mice. We also found that FKS stimulated production of IL-1Ra by bone marrow-derived dendritic cells (BMDCs), independent of MyD88 and Dectin-1. There also was a very high concentration of IL-1Ra in the lungs of infected B6 mice, supporting the potential importance of this regulatory IL-1 family protein in the largely ineffective response of B6 mice to coccidioidomycosis. These results suggest that IL-1R1 signaling is important for defense against C. immitis infection.
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English BC, Van Prooyen N, Örd T, Örd T, Sil A. The transcription factor CHOP, an effector of the integrated stress response, is required for host sensitivity to the fungal intracellular pathogen Histoplasma capsulatum. PLoS Pathog 2017; 13:e1006589. [PMID: 28953979 PMCID: PMC5633207 DOI: 10.1371/journal.ppat.1006589] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2017] [Revised: 10/09/2017] [Accepted: 08/17/2017] [Indexed: 02/06/2023] Open
Abstract
The ability of intracellular pathogens to manipulate host-cell viability is critical to successful infection. Some pathogens promote host-cell survival to protect their replicative niche, whereas others trigger host-cell death to facilitate release and dissemination of the pathogen after intracellular replication has occurred. We previously showed that the intracellular fungal pathogen Histoplasma capsulatum (Hc) uses the secreted protein Cbp1 to actively induce apoptosis in macrophages; interestingly, cbp1 mutant strains are unable to kill macrophages and display severely reduced virulence in the mouse model of Hc infection. To elucidate the mechanism of Cbp1-induced host-cell death, we performed a comprehensive alanine scanning mutagenesis and identified all amino acid residues that are required for Cbp1 to trigger macrophage lysis. Here we demonstrate that Hc strains expressing lytic CBP1 alleles activate the integrated stress response (ISR) in infected macrophages, as indicated by an increase in eIF2α phosphorylation as well as induction of the transcription factor CHOP and the pseudokinase Tribbles 3 (TRIB3). In contrast, strains bearing a non-lytic allele of CBP1 fail to activate the ISR, whereas a partially lytic CBP1 allele triggers intermediate levels of activation. We further show that macrophages deficient for CHOP or TRIB3 are partially resistant to lysis during Hc infection, indicating that the ISR is critical for susceptibility to Hc-mediated cell death. Moreover, we show that CHOP-dependent macrophage lysis is critical for efficient spread of Hc infection to other macrophages. Notably, CHOP knockout mice display reduced macrophage apoptosis and diminished fungal burden and are markedly resistant to Hc infection. Together, these data indicate that Cbp1 is required for Hc to induce the ISR and mediate a CHOP-dependent virulence pathway in the host. Histoplasma capsulatum is the causative agent of histoplasmosis, a fungal infection that can be fatal in a wide range of mammalian hosts, including otherwise healthy, immunocompetent individuals. Histoplasma cells replicate to very high levels within host macrophages, eventually causing macrophage death and the release of live fungal cells. Here, we show that Histoplasma yeast use the secreted protein Cbp1 to activate a specific signaling pathway in the host cell to cause macrophage death during infection. Importantly, this signaling cascade is essential for pathogenesis, and mice deficient for a central component of this pathway are resistant to Histoplasma infection. Our study is the first demonstration that Histoplasma employs a secreted effector to alter host signaling pathways to promote virulence, and thus provides key insight into the pathogenesis strategies of this important human fungal pathogen.
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Affiliation(s)
- Bevin C. English
- Department of Microbiology and Immunology, University of California San Francisco, San Francisco, California, United States of America
| | - Nancy Van Prooyen
- Department of Microbiology and Immunology, University of California San Francisco, San Francisco, California, United States of America
- FLX Bio, South San Francisco, California, United States of America
| | - Tiit Örd
- Institute of Molecular and Cell Biology, University of Tartu, Tartu, Estonia
- Estonian Biocentre, Tartu, Estonia
| | | | - Anita Sil
- Department of Microbiology and Immunology, University of California San Francisco, San Francisco, California, United States of America
- * E-mail:
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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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Werner JL, Escolero SG, Hewlett JT, Mak TN, Williams BP, Eishi Y, Núñez G. Induction of Pulmonary Granuloma Formation by Propionibacterium acnes Is Regulated by MyD88 and Nox2. Am J Respir Cell Mol Biol 2017; 56:121-130. [PMID: 27607191 DOI: 10.1165/rcmb.2016-0035oc] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023] Open
Abstract
Sarcoidosis is characterized by noncaseating granulomas with an unknown cause that present primarily in the lung. Propionibacterium acnes, an immunogenic commensal skin bacterium involved in acne vulgaris, has been implicated as a possible causative agent of sarcoidosis. Here, we demonstrate that a viable strain of P. acnes isolated from a patient with sarcoidosis and instilled intratracheally into wild-type mice can generate pulmonary granulomas similar to those observed in patients with sarcoidosis. The formation of these granulomas is dependent on the administration of viable P. acnes. We also found that mice deficient in the innate immunity adapter protein MyD88 had a greater number and a larger area of granuloma lesions compared with wild-type mice administered P. acnes. Early after P. acnes administration, wild-type mice produced proinflammatory mediators and recruited neutrophils into the lung, a response that is dependent on MyD88. In addition, there was an increase in granuloma number and size after instillation with P. acnes in mice deficient in CybB, a critical component of nicotinamide adenine dinucleotide phosphate oxidase required for the production of reactive oxygen species in the phagosome. Myd88-/- or Cybb-/- mice both had increased persistence of P. acnes in the lung, together with enhanced granuloma formation. In conclusion, we have generated a mouse model of early granuloma formation induced by a clinically relevant strain of P. acnes isolated from a patient with sarcoidosis, and, using this model, we have shown that a deficiency in MyD88 or CybB is associated with impaired bacterial clearance and increased granuloma formation in the lung.
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Affiliation(s)
- Jessica L Werner
- 1 Department of Pathology and Comprehensive Cancer Center, University of Michigan Medical School, Ann Arbor, Michigan; and
| | - Sylvia G Escolero
- 1 Department of Pathology and Comprehensive Cancer Center, University of Michigan Medical School, Ann Arbor, Michigan; and
| | - Jeff T Hewlett
- 1 Department of Pathology and Comprehensive Cancer Center, University of Michigan Medical School, Ann Arbor, Michigan; and
| | - Tim N Mak
- 1 Department of Pathology and Comprehensive Cancer Center, University of Michigan Medical School, Ann Arbor, Michigan; and
| | - Brian P Williams
- 1 Department of Pathology and Comprehensive Cancer Center, University of Michigan Medical School, Ann Arbor, Michigan; and
| | - Yoshinobu Eishi
- 2 Department of Human Pathology, Graduate School and Faculty of Medicine, Tokyo Medical and Dental University, Tokyo, Japan
| | - Gabriel Núñez
- 1 Department of Pathology and Comprehensive Cancer Center, University of Michigan Medical School, Ann Arbor, Michigan; and
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12
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Pathogen–Host Interaction of Histoplasma capsulatum: an Update. CURRENT FUNGAL INFECTION REPORTS 2016. [DOI: 10.1007/s12281-016-0267-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
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13
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Van Prooyen N, Henderson CA, Hocking Murray D, Sil A. CD103+ Conventional Dendritic Cells Are Critical for TLR7/9-Dependent Host Defense against Histoplasma capsulatum, an Endemic Fungal Pathogen of Humans. PLoS Pathog 2016; 12:e1005749. [PMID: 27459510 PMCID: PMC4961300 DOI: 10.1371/journal.ppat.1005749] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2015] [Accepted: 06/17/2016] [Indexed: 11/23/2022] Open
Abstract
Innate immune cells shape the host response to microbial pathogens. Here we elucidate critical differences in the molecular response of macrophages vs. dendritic cells (DCs) to Histoplasma capsulatum, an intracellular fungal pathogen of humans. It has long been known that macrophages are permissive for Histoplasma growth and succumb to infection, whereas DCs restrict fungal growth and survive infection. We used murine macrophages and DCs to identify host pathways that influence fungal proliferation and host-cell viability. Transcriptional profiling experiments revealed that DCs produced a strong Type I interferon (IFN-I) response to infection with Histoplasma yeasts. Toll-like receptors 7 and 9 (TLR7/9), which recognize nucleic acids, were required for IFN-I production and restriction of fungal growth in DCs, but mutation of TLR7/9 had no effect on the outcome of macrophage infection. Moreover, TLR7/9 were essential for the ability of infected DCs to elicit production of the critical cytokine IFNγ from primed CD4+ T cells in vitro, indicating the role of this pathway in T cell activation. In a mouse model of infection, TLR7/9 were required for optimal production of IFN-I and IFNγ, host survival, and restriction of cerebral fungal burden. These data demonstrate the critical role of this pathway in eliciting an appropriate adaptive immune response in the host. Finally, although other fungal pathogens have been shown to elicit IFN-I in mouse models, the specific host cell responsible for producing IFN-I has not been elucidated. We found that CD103+ conventional DCs were the major producer of IFN-I in the lungs of wild-type mice infected with Histoplasma. Mice deficient in this DC subtype displayed reduced IFN-I production in vivo. These data reveal a previously unknown role for CD103+ conventional DCs and uncover the pivotal function of these cells in modulating the host immune response to endemic fungi. Innate immune cells such as macrophages and dendritic cells (DCs) are critical elements of the initial response to pathogens. Whereas both of these cell types utilize robust anti-microbial strategies to kill internalized microbes, intracellular pathogens have developed mechanisms to manipulate the host response and survive within host cells. In the case of the intracellular fungal pathogen Histoplasma capsulatum, the fungus proliferates within macrophages, resulting in host-cell lysis. In contrast, DCs are able to restrict Histoplasma growth. Here we discovered that the ability of DCs to produce Type I interferons (IFN-I) is critical to their capacity to restrict fungal proliferation and survive infection. IFN-I are cytokines that are elicited during a variety of viral, bacterial, and fungal infections. We performed in vivo and in vitro experiments to show that pattern recognition receptors TLR7 and TLR9 are critical for the IFN-I response and host survival in the mouse model of infection. Additionally we defined a specific DC subset (CD103+ conventional DCs) in the mouse lung that is responsible for the IFN-I response, revealing a previously unknown role for these cells. These data provide insight on the pivotal role of a specific host-response pathway at both a cellular and organismal level during infection with endemic fungi.
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Affiliation(s)
- Nancy Van Prooyen
- Department of Microbiology and Immunology, University of California San Francisco, San Francisco, California, United States of America
| | - C. Allen Henderson
- Department of Microbiology and Immunology, University of California San Francisco, San Francisco, California, United States of America
| | - Davina Hocking Murray
- Department of Microbiology and Immunology, University of California San Francisco, San Francisco, California, United States of America
| | - Anita Sil
- Department of Microbiology and Immunology, University of California San Francisco, San Francisco, California, United States of America
- Howard Hughes Medical Institute, San Francisco, California, United States of America
- * E-mail:
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14
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Immune Reconstitution Inflammatory Syndrome in Invasive Fungal Infections: What We Know and What We Need to Know? CURRENT CLINICAL MICROBIOLOGY REPORTS 2016. [DOI: 10.1007/s40588-016-0033-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
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15
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Garfoot AL, Rappleye CA. Histoplasma capsulatum surmounts obstacles to intracellular pathogenesis. FEBS J 2015; 283:619-33. [PMID: 26235362 DOI: 10.1111/febs.13389] [Citation(s) in RCA: 49] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2015] [Revised: 07/25/2015] [Accepted: 07/27/2015] [Indexed: 11/28/2022]
Abstract
The fungal pathogen Histoplasma capsulatum causes respiratory and disseminated disease, even in immunocompetent hosts. In contrast to opportunistic pathogens, which are readily controlled by phagocytic cells, H. capsulatum yeasts are able to infect macrophages, survive antimicrobial defenses, and proliferate as an intracellular pathogen. In this review, we discuss some of the molecular mechanisms that enable H. capsulatum yeasts to overcome obstacles to intracellular pathogenesis. H. capsulatum yeasts gain refuge from extracellular obstacles such as antimicrobial lung surfactant proteins by engaging the β-integrin family of phagocytic receptors to promote entry into macrophages. In addition, H. capsulatum yeasts conceal immunostimulatory β-glucans to avoid triggering signaling receptors such as the β-glucan receptor Dectin-1. H. capsulatum yeasts counteract phagocyte-produced reactive oxygen species by expression of oxidative stress defense enzymes including an extracellular superoxide dismutase and an extracellular catalase. Within the phagosome, H. capsulatum yeasts block phagosome acidification, acquire essential metals such as iron and zinc, and utilize de novo biosynthesis pathways to overcome nutritional limitations. These mechanisms explain how H. capsulatum yeasts avoid and negate macrophage defense strategies and establish a hospitable intracellular niche, making H. capsulatum a successful intracellular pathogen of macrophages.
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Affiliation(s)
- Andrew L Garfoot
- Department of Microbiology, Department of Microbial Infection and Immunity, Ohio State University, Columbus, OH, USA
| | - Chad A Rappleye
- Department of Microbiology, Department of Microbial Infection and Immunity, Ohio State University, Columbus, OH, USA
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