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Zhao X, Shen L, Zheng J, Zhu H, Li L, Shi H, Chen Z, Li Q. C1q Confers Protection Against Cryptococcal Lung Infection by Alleviating Inflammation and Reducing Cryptococcal Virulence. Open Forum Infect Dis 2023; 10:ofad151. [PMID: 37089772 PMCID: PMC10117377 DOI: 10.1093/ofid/ofad151] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2022] [Accepted: 03/20/2023] [Indexed: 04/25/2023] Open
Abstract
Background To define the role of C1qa in host defense against Cryptococcus neoformans lung infection, we investigated its susceptibility to cryptococcal lung infection in mice deficient in complement factor C1qa (C1qa-/- ). Methods We established a wild-type (WT) and C1qa-deficient murine inhalation model with C. neoformans. We compared the host survival rate, inflammatory responses, and pathogenicity of C. neoformans during the infection course between WT and C1qa-/- mice. Results The mortality rate of C1qa-deficient mice was significantly higher than that of wild-type mice. The increased formation of Titan cells in the lungs was associated with augmented inflammation in C1qa-deficient mice. The capacity of lung homogenate supernatant from C1qa-deficient mice to induce Titan formation in vitro was greater compared with that of wild-type mice. The C. neoformans isolated from the lungs of infected C1qa-deficient mice was more resistant to macrophage killing in vitro and caused significantly higher mortality after administration to mice compared with that isolated from WT mice. Conclusions These findings reveal a novel role of C1qa in host defense against C. neoformans infection by regulating host inflammation and pathogen virulence and provide new insight into the C1q-mediated lung environment underlying the transition from yeast to Titan cell.
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Affiliation(s)
| | | | | | - Haiyan Zhu
- Department of Biological Medicines & Shanghai Engineering Research Center of ImmunoTherapeutics, School of Pharmacy, Fudan University, Shanghai, China
| | - Li Li
- Laboratory of Mycology, Department of Dermatology, Huashan Hospital, Fudan University, Shanghai, China
| | - Hong Shi
- Department of Anesthesiology, Shanghai Pulmonary Hospital, School of Medicine, Tongji University, Shanghai, China
| | - Zhongqing Chen
- Correspondence: Zhongqing Chen, MD, PhD, Department of Pathology, Huashan Hospital, Fudan University, 12 Wulumuqi Zhong Road, Shanghai, 200040, China (); Qian Li, Department of Infectious Diseases, Shanghai Key Laboratory of Infectious Diseases and Biosafety Emergency Response, National Medical Center for Infectious Diseases, Huashan Hospital, Fudan University, 12 Wulumuqi Zhong Road, Shanghai, 200040, China ()
| | - Qian Li
- Correspondence: Zhongqing Chen, MD, PhD, Department of Pathology, Huashan Hospital, Fudan University, 12 Wulumuqi Zhong Road, Shanghai, 200040, China (); Qian Li, Department of Infectious Diseases, Shanghai Key Laboratory of Infectious Diseases and Biosafety Emergency Response, National Medical Center for Infectious Diseases, Huashan Hospital, Fudan University, 12 Wulumuqi Zhong Road, Shanghai, 200040, China ()
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2
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Abstract
The respiratory tree maintains sterilizing immunity against human fungal pathogens. Humans inhale ubiquitous filamentous molds and geographically restricted dimorphic fungal pathogens that form small airborne conidia. In addition, pathogenic yeasts, exemplified by encapsulated Cryptococcus species, and Pneumocystis pose significant fungal threats to the lung. Classically, fungal pneumonia occurs in immune compromised individuals, specifically in patients with HIV/AIDS, in patients with hematologic malignancies, in organ transplant recipients, and in patients treated with corticosteroids and targeted biologics that impair fungal immune surveillance in the lung. The emergence of fungal co-infections during severe influenza and COVID-19 underscores the impairment of fungus-specific host defense pathways in the lung by respiratory viruses and by medical therapies to treat viral infections. Beyond life-threatening invasive syndromes, fungal antigen exposure can exacerbate allergenic disease in the lung. In this review, we discuss emerging principles of lung-specific antifungal immunity, integrate the contributions and cooperation of lung epithelial, innate immune, and adaptive immune cells to mucosal barrier immunity, and highlight the pathogenesis of fungal-associated allergenic disease. Improved understanding of fungus-specific immunity in the respiratory tree has paved the way to develop improved diagnostic, pre-emptive, therapeutic, and vaccine approaches for fungal diseases of the lung.
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Affiliation(s)
- Lena J Heung
- Division of Infectious Diseases, Department of Medicine, Cedars-Sinai Medical Center, Los Angeles, CA, USA; Research Division of Immunology, Department of Biomedical Sciences, Cedars-Sinai Medical Center, Los Angeles, CA, USA; Women's Guild Lung Institute, Cedars-Sinai Medical Center, Los Angeles, CA, USA
| | - Darin L Wiesner
- Center for Immunity and Inflammation, New Jersey Medical School, Rutgers Biomedical and Health Sciences, Newark, NJ, USA
| | - Keyi Wang
- Center for Immunity and Inflammation, New Jersey Medical School, Rutgers Biomedical and Health Sciences, Newark, NJ, USA
| | - Amariliz Rivera
- Center for Immunity and Inflammation, New Jersey Medical School, Rutgers Biomedical and Health Sciences, Newark, NJ, USA
| | - Tobias M Hohl
- Infectious Disease Service, Department of Medicine, Memorial Sloan Kettering Cancer Center, New York, NY, USA; Human Oncology and Pathogenesis Program, Memorial Sloan Kettering Cancer Center, New York, NY, USA.
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3
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Denham ST, Brammer B, Chung KY, Wambaugh MA, Bednarek JM, Guo L, Moreau CT, Brown JCS. A dissemination-prone morphotype enhances extrapulmonary organ entry by Cryptococcus neoformans. Cell Host Microbe 2022; 30:1382-1400.e8. [PMID: 36099922 PMCID: PMC9588642 DOI: 10.1016/j.chom.2022.08.017] [Citation(s) in RCA: 18] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2022] [Revised: 06/01/2022] [Accepted: 08/18/2022] [Indexed: 01/08/2023]
Abstract
Environmental pathogens move from ecological niches to mammalian hosts, requiring adaptation to dramatically different environments. Microbes that disseminate farther, including the fungal meningitis pathogen Cryptococcus neoformans, require additional adaptation to diverse tissues. We demonstrate that the formation of a small C. neoformans morphotype-called "seed" cells due to their colonizing ability-is critical for extrapulmonary organ entry. Seed cells exhibit changes in fungal cell size and surface expression that result in an enhanced macrophage update. Seed cell formation is triggered by environmental factors, including C. neoformans' environmental niche, and pigeon guano with phosphate plays a central role. Seed cells show the enhanced expression of phosphate acquisition genes, and mutants unable to acquire phosphate fail to adopt the seed cell morphotype. Additionally, phosphate can be released by tissue damage, potentially establishing a feed-forward loop of seed cell formation and dissemination. Thus, C. neoformans' size variation represent inducible morphotypes that change host interactions to facilitate microbe spread.
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Affiliation(s)
- Steven T Denham
- Division of Microbiology and Immunology, Department of Pathology, University of Utah, Salt Lake City, UT 84112, USA
| | - Brianna Brammer
- Division of Microbiology and Immunology, Department of Pathology, University of Utah, Salt Lake City, UT 84112, USA
| | - Krystal Y Chung
- Division of Microbiology and Immunology, Department of Pathology, University of Utah, Salt Lake City, UT 84112, USA
| | - Morgan A Wambaugh
- Division of Microbiology and Immunology, Department of Pathology, University of Utah, Salt Lake City, UT 84112, USA
| | - Joseph M Bednarek
- Division of Microbiology and Immunology, Department of Pathology, University of Utah, Salt Lake City, UT 84112, USA
| | - Li Guo
- Molecular Medicine Program, University of Utah, Salt Lake City, UT 84112, USA
| | - Christian T Moreau
- Division of Microbiology and Immunology, Department of Pathology, University of Utah, Salt Lake City, UT 84112, USA
| | - Jessica C S Brown
- Division of Microbiology and Immunology, Department of Pathology, University of Utah, Salt Lake City, UT 84112, USA.
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4
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Berguson HP, Caulfield LW, Price MS. Influence of Pathogen Carbon Metabolism on Interactions With Host Immunity. Front Cell Infect Microbiol 2022; 12:861405. [PMID: 35372116 PMCID: PMC8968422 DOI: 10.3389/fcimb.2022.861405] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2022] [Accepted: 02/24/2022] [Indexed: 11/22/2022] Open
Abstract
Cryptococcus neoformans is a ubiquitous opportunistic fungal pathogen typically causing disease in immunocompromised individuals and is globally responsible for about 15% of AIDS-related deaths annually. C. neoformans first causes pulmonary infection in the host and then disseminates to the brain, causing meningoencephalitis. The yeast must obtain and metabolize carbon within the host in order to survive in the central nervous system and cause disease. Communication between pathogen and host involves recognition of multiple carbon-containing compounds on the yeast surface: polysaccharide capsule, fungal cell wall, and glycosylated proteins comprising the major immune modulators. The structure and function of polysaccharide capsule has been studied for the past 70 years, emphasizing its role in virulence. While protected by the capsule, fungal cell wall has likewise been a focus of study for several decades for its role in cell integrity and host recognition. Associated with both of these major structures are glycosylated proteins, which exhibit known immunomodulatory effects. While many studies have investigated the role of carbon metabolism on virulence and survival within the host, the precise mechanism(s) affecting host-pathogen communication remain ill-defined. This review summarizes the current knowledge on mutants in carbon metabolism and their effect on the host immune response that leads to changes in pathogen recognition and virulence. Understanding these critical interactions will provide fresh perspectives on potential treatments and the natural history of cryptococcal disease.
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Affiliation(s)
- Hannah P. Berguson
- Department of Anatomical Sciences, Liberty University College of Osteopathic Medicine, Lynchburg, VA, United States
| | - Lauren W. Caulfield
- Department of Biology and Chemistry, Liberty University, Lynchburg, VA, United States
| | - Michael S. Price
- Department of Molecular and Cellular Sciences, Liberty University College of Osteopathic Medicine, Lynchburg, VA, United States
- Department of Medicine, Duke University School of Medicine, Durham, NC, United States
- *Correspondence: Michael S. Price,
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5
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Sun Z, Ji N, Jiang J, Tao Y, Zhang E, Yang X, Wang Z, Chen Z, Huang M, Zhang M. Fine Particulate Matter (PM 2. 5) Promotes CD146 Expression in Alveolar Epithelial Cells and Cryptococcus neoformans Pulmonary Infection. Front Microbiol 2021; 11:525976. [PMID: 33537006 PMCID: PMC7848894 DOI: 10.3389/fmicb.2020.525976] [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: 01/11/2020] [Accepted: 12/14/2020] [Indexed: 11/13/2022] Open
Abstract
Air pollution is a leading cause of increasing infectious lung diseases. Pulmonary cryptococcosis is a fatal fungal pneumonia in acquired immunodeficiency syndrome patients. In some cases, the pathogen Cryptococcus neoformans also develops dormant nodules in immunocompetent individuals. In the present study, we demonstrated that fine particulate matter (PM2.5) increased CD146 expression in alveolar epithelial cells and promoted C. neoformans pulmonary infection. Aryl hydrocarbon receptor (AhR) signaling was required for increased expression of CD146 in epithelial cells treated with PM2.5. In a murine model of pulmonary infection, PM2.5 promoted fungal infection, and CD146 deficiency decreased the fugal burden of C. neoformans. Our study may highlight the importance of air pollution to lung mycosis and CD146 as a target for preventing infectious lung diseases.
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Affiliation(s)
- Zhixiao Sun
- Department of Respiratory and Critical Care Medicine, The First Affiliated Hospital of Nanjing Medical University, Nanjing, China
| | - Ningfei Ji
- Department of Respiratory and Critical Care Medicine, The First Affiliated Hospital of Nanjing Medical University, Nanjing, China
| | - Jingxian Jiang
- Department of Respiratory and Critical Care Medicine, The First Affiliated Hospital of Nanjing Medical University, Nanjing, China
| | - Yuan Tao
- NHC Key Laboratory of Antibody Technique, Department of Immunology, Nanjing Medical University, Nanjing, China
| | - Enrui Zhang
- NHC Key Laboratory of Antibody Technique, Department of Immunology, Nanjing Medical University, Nanjing, China
| | - Xiaofan Yang
- Laboratory Center for Basic Medical Sciences, Nanjing Medical University, Nanjing, China
| | - Zhengxia Wang
- Department of Respiratory and Critical Care Medicine, The First Affiliated Hospital of Nanjing Medical University, Nanjing, China
| | - Zhongqi Chen
- Department of Respiratory and Critical Care Medicine, The First Affiliated Hospital of Nanjing Medical University, Nanjing, China
| | - Mao Huang
- Department of Respiratory and Critical Care Medicine, The First Affiliated Hospital of Nanjing Medical University, Nanjing, China
| | - Mingshun Zhang
- NHC Key Laboratory of Antibody Technique, Department of Immunology, Nanjing Medical University, Nanjing, China
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6
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Madan T, Kishore U. Surfactant Protein D Recognizes Multiple Fungal Ligands: A Key Step to Initiate and Intensify the Anti-fungal Host Defense. Front Cell Infect Microbiol 2020; 10:229. [PMID: 32547959 PMCID: PMC7272678 DOI: 10.3389/fcimb.2020.00229] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2020] [Accepted: 04/23/2020] [Indexed: 12/11/2022] Open
Abstract
With limited therapeutic options and associated severe adverse effects, fungal infections are a serious threat to human health. Innate immune response mediated by pattern recognition proteins is integral to host defense against fungi. A soluble pattern recognition protein, Surfactant protein D (SP-D), plays an important role in immune surveillance to detect and eliminate human pathogens. SP-D exerts its immunomodulatory activity via direct interaction with several receptors on the epithelial cells lining the mucosal tracts, as well as on innate and adaptive immune cells. Being a C-type lectin, SP-D shows calcium- and sugar-dependent interactions with several glycosylated ligands present on fungal cell walls. The interactome includes cell wall polysaccharides such as 1,3-β-D-glucan, 1,6-β-D-glucan, Galactosaminogalactan Galactomannan, Glucuronoxylomannan, Mannoprotein 1, and glycosylated proteins such as gp45, gp55, major surface glycoprotein complex (gpA). Recently, binding of a recombinant fragment of human SP-D to melanin on the dormant conidia of Aspergillus fumigatus was demonstrated that was not inhibited by sugars, suggesting a likely protein-protein interaction. Interactions of the ligands on the fungal spores with the oligomeric forms of full-length SP-D resulted in formation of spore-aggregates, increased uptake by phagocytes and rapid clearance besides a direct fungicidal effect against C. albicans. Exogenous administration of SP-D showed significant therapeutic potential in murine models of allergic and invasive mycoses. Altered susceptibility of SP-D gene-deficient mice to various fungal infections emphasized relevance of SP-D as an important sentinel of anti-fungal immunity. Levels of SP-D in the serum or lung lavage were significantly altered in the murine models and patients of fungal infections and allergies. Here, we review the cell wall ligands of clinically relevant fungal pathogens and allergens that are recognized by SP-D and their impact on the host defense. Elucidation of the molecular interactions between innate immune humoral such as SP-D and fungal pathogens would facilitate the development of novel therapeutic interventions.
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Affiliation(s)
- Taruna Madan
- Department of Innate Immunity, ICMR-National Institute for Research in Reproductive Health, Mumbai, India
| | - Uday Kishore
- Biosciences, College of Health and Life Sciences, Brunel University London, Uxbridge, United Kingdom
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7
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Murugaiah V, Tsolaki AG, Kishore U. Collectins: Innate Immune Pattern Recognition Molecules. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2020; 1204:75-127. [PMID: 32152944 PMCID: PMC7120701 DOI: 10.1007/978-981-15-1580-4_4] [Citation(s) in RCA: 24] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Collectins are collagen-containing C-type (calcium-dependent) lectins which are important pathogen pattern recognising innate immune molecules. Their primary structure is characterised by an N-terminal, triple-helical collagenous region made up of Gly-X-Y repeats, an a-helical coiled-coil trimerising neck region, and a C-terminal C-type lectin or carbohydrate recognition domain (CRD). Further oligomerisation of this primary structure can give rise to more complex and multimeric structures that can be seen under electron microscope. Collectins can be found in serum as well as in a range of tissues at the mucosal surfaces. Mannanbinding lectin can activate the complement system while other members of the collectin family are extremely versatile in recognising a diverse range of pathogens via their CRDs and bring about effector functions designed at the clearance of invading pathogens. These mechanisms include opsonisation, enhancement of phagocytosis, triggering superoxidative burst and nitric oxide production. Collectins can also potentiate the adaptive immune response via antigen presenting cells such as macrophages and dendritic cells through modulation of cytokines and chemokines, thus they can act as a link between innate and adaptive immunity. This chapter describes the structure-function relationships of collectins, their diverse functions, and their interaction with viruses, bacteria, fungi and parasites.
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Affiliation(s)
- Valarmathy Murugaiah
- College of Health and Life Sciences, Brunel University London, London, UB8 3PH, UK
| | - Anthony G Tsolaki
- College of Health and Life Sciences, Brunel University London, London, UB8 3PH, UK
| | - Uday Kishore
- College of Health and Life Sciences, Brunel University London, London, UB8 3PH, UK.
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8
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Abstract
Among fungal pathogens, Cryptococcus neoformans has gained great importance among the scientific community of several reasons. This fungus is the causative agent of cryptococcosis, a disease mainly associated to HIV immunosuppression and characterized by the appearance of meningoencephalitis. Cryptococcal meningitis is responsible for hundreds of thousands of deaths every year. Research of the pathogenesis and virulence mechanisms of this pathogen has focused on three main different areas: Adaptation to the host environment (nutrients, pH, and free radicals), mechanism of immune evasion (which include phenotypic variations and the ability to behave as a facultative intracellular pathogen), and production of virulence factors. Cryptococcus neoformans has two phenotypic characteristics, the capsule and synthesis of melanin that have a profound effect in the virulence of the yeast because they both have protective effects and induce host damage as virulence factors. Finally, the mechanisms that result in dissemination and brain invasion are also of key importance to understand cryptococcal disease. In this review, I will provide a brief overview of the main mechanisms that makes C. neoformans a pathogen in susceptible patients. Abbreviations: RNS: reactive nitrogen species; BBB: brain blood barrier; GXM: glucuronoxylomannan; GXMGal: glucuronoxylomannogalactan
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Affiliation(s)
- Oscar Zaragoza
- a Mycology Reference Laboratory National Centre for Microbiology , Instituto de Salud Carlos III Carretera Majadahonda-Pozuelo , Madrid , Spain
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9
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Abstract
The respiratory tract is tasked with responding to a constant and vast influx of foreign agents. It acts as an important first line of defense in the innate immune system and as such plays a crucial role in preventing the entry of invading pathogens. While physical barriers like the mucociliary escalator exert their effects through the clearance of these pathogens, diverse and dynamic cellular mechanisms exist for the activation of the innate immune response through the recognition of pathogen-associated molecular patterns (PAMPs). These PAMPs are recognized by pattern recognition receptors (PRRs) that are expressed on a number of myeloid cells such as dendritic cells, macrophages, and neutrophils found in the respiratory tract. C-type lectin receptors (CLRs) are PRRs that play a pivotal role in the innate immune response and its regulation to a variety of respiratory pathogens such as viruses, bacteria, and fungi. This chapter will describe the function of both activating and inhibiting myeloid CLRs in the recognition of a number of important respiratory pathogens as well as the signaling events initiated by these receptors.
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10
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The Role of Melanin in Fungal Pathogenesis for Animal Hosts. Curr Top Microbiol Immunol 2019; 422:1-30. [PMID: 31278515 DOI: 10.1007/82_2019_173] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Melanins are a class of pigments that are ubiquitous throughout biology. They play incredibly diverse and important roles ranging from radiation protection to immune defense, camouflage, and virulence. Fungi have evolved to use melanin to be able to persist in the environment and within organisms. Fungal melanins are often located within the cell well and are able to neutralize reactive oxygen species and other radicals, defend against UV radiation, bind and sequester non-specific peptides and compounds, and produce a physical barrier that defends the cell. For this reason, melanized fungi are often well-suited to be human pathogens-melanin allows fungi to neutralize the microbicidal oxidative bursts of our innate immune system, bind and inactivate to antimicrobial peptides and enzymes, sequester antifungal pharmaceuticals, and create a shield to block immune recognition of the fungus. Due to the importance and pervasiveness of melanin in fungal virulence, mammalian immune systems have evolved antifungal strategies that involve directly detecting and binding to fungal melanins. Such strategies include the use of melanin-specific antibody responses and C-type lectins like the newly discovered melanin-specific MelLec receptor.
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11
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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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12
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Maintenance of Mitochondrial Morphology in Cryptococcus neoformans Is Critical for Stress Resistance and Virulence. mBio 2018; 9:mBio.01375-18. [PMID: 30401774 PMCID: PMC6222134 DOI: 10.1128/mbio.01375-18] [Citation(s) in RCA: 25] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
C. neoformans is a yeast that causes fatal brain infection in close to 200,000 people worldwide every year, mainly afflicting individuals with AIDS or others who are severely immunocompromised. One feature of this microbe that helps it cause disease is that it is able to withstand toxic molecules it encounters when host cells engulf it in their efforts to control the infection. Mitochondria are important organelles responsible for energy production and other key cellular processes. They typically exist in a complex network that changes morphology by fusing and dividing; these alterations also influence mitochondrial function. Using genetic approaches, we found that changes in mitochondrial morphology dramatically influence cryptococcal virulence. We showed that this occurs because the altered mitochondria are less able to eliminate the harmful molecules that host cells produce to kill invading microbes. These findings are important because they elucidate fundamental biology and virulence and may suggest avenues for therapy. Mitochondria are essential organelles that act in pathways including ATP production, β-oxidation, and clearance of reactive oxygen species. They occur as a complex reticular network that constantly undergoes fusion and fission, mediated by dynamin-related proteins (DRPs). DRPs include Fzo1, which mediates fusion, and Dnm1, Mdv1, and Fis1, which mediate fission. Mitochondrial morphology has been implicated in virulence in multiple fungi, as with the association between virulence and increased mitochondrial fusion in Cryptococcus gattii. This relationship, however, has not been studied in Cryptococcus neoformans, a related opportunistic pathogen. C. neoformans is an environmental yeast that can adapt to the human host environment, overcome the innate immune system, and eventually disseminate and cause lethal meningoencephalitis. We used gene deletion of key DRPs to study their role in mitochondrial morphology and pathogenesis of this yeast. Interestingly, increasing mitochondrial fusion did not increase resistance to oxidative stress, unlike in model yeast. Blocking mitochondrial fusion, however, yielded increased susceptibility to oxidative and nitrosative stresses as well as complete avirulence. This lack of virulence was not mediated by any effects of altered mitochondrial function on two major virulence factors, capsule and melanin. Instead, it was due to decreased survival within macrophages, which in turn was a consequence of increased susceptibility to oxidative and nitrosative stress. Supporting this conclusion, reactive oxygen species (ROS) scavengers rescued the ability of fusion mutants to survive intracellularly. These findings increase our understanding of cryptococcal biology and virulence and shed light on an important group of proteins and cellular processes in this pathogen.
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13
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Goyal S, Castrillón-Betancur JC, Klaile E, Slevogt H. The Interaction of Human Pathogenic Fungi With C-Type Lectin Receptors. Front Immunol 2018; 9:1261. [PMID: 29915598 PMCID: PMC5994417 DOI: 10.3389/fimmu.2018.01261] [Citation(s) in RCA: 82] [Impact Index Per Article: 13.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2018] [Accepted: 05/18/2018] [Indexed: 01/19/2023] Open
Abstract
Fungi, usually present as commensals, are a major cause of opportunistic infections in immunocompromised patients. Such infections, if not diagnosed or treated properly, can prove fatal. However, in most cases healthy individuals are able to avert the fungal attacks by mounting proper antifungal immune responses. Among the pattern recognition receptors (PRRs), C-type lectin receptors (CLRs) are the major players in antifungal immunity. CLRs can recognize carbohydrate ligands, such as β-glucans and mannans, which are mainly found on fungal cell surfaces. They induce proinflammatory immune reactions, including phagocytosis, oxidative burst, cytokine, and chemokine production from innate effector cells, as well as activation of adaptive immunity via Th17 responses. CLRs such as Dectin-1, Dectin-2, Mincle, mannose receptor (MR), and DC-SIGN can recognize many disease-causing fungi and also collaborate with each other as well as other PRRs in mounting a fungi-specific immune response. Mutations in these receptors affect the host response and have been linked to a higher risk in contracting fungal infections. This review focuses on how CLRs on various immune cells orchestrate the antifungal response and on the contribution of single nucleotide polymorphisms in these receptors toward the risk of developing such infections.
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Affiliation(s)
- Surabhi Goyal
- Institute for Microbiology and Hygiene, Charité - Universitätsmedizin Berlin, Berlin, Germany.,Septomics Research Center, Jena University Hospital, Jena, Germany
| | - Juan Camilo Castrillón-Betancur
- Septomics Research Center, Jena University Hospital, Jena, Germany.,International Leibniz Research School for Microbial and Biomolecular Interactions, Leibniz Institute for Natural Product Research and Infection Biology/Hans Knöll Institute, Jena, Germany
| | - Esther Klaile
- Septomics Research Center, Jena University Hospital, Jena, Germany
| | - Hortense Slevogt
- Septomics Research Center, Jena University Hospital, Jena, Germany
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14
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Hommel B, Mukaremera L, Cordero RJB, Coelho C, Desjardins CA, Sturny-Leclère A, Janbon G, Perfect JR, Fraser JA, Casadevall A, Cuomo CA, Dromer F, Nielsen K, Alanio A. Titan cells formation in Cryptococcus neoformans is finely tuned by environmental conditions and modulated by positive and negative genetic regulators. PLoS Pathog 2018; 14:e1006982. [PMID: 29775480 PMCID: PMC5959062 DOI: 10.1371/journal.ppat.1006982] [Citation(s) in RCA: 86] [Impact Index Per Article: 14.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2017] [Accepted: 03/19/2018] [Indexed: 01/06/2023] Open
Abstract
The pathogenic fungus Cryptococcus neoformans exhibits morphological changes in cell size during lung infection, producing both typical size 5 to 7 μm cells and large titan cells (> 10 μm and up to 100 μm). We found and optimized in vitro conditions that produce titan cells in order to identify the ancestry of titan cells, the environmental determinants, and the key gene regulators of titan cell formation. Titan cells generated in vitro harbor the main characteristics of titan cells produced in vivo including their large cell size (>10 μm), polyploidy with a single nucleus, large vacuole, dense capsule, and thick cell wall. Here we show titan cells derived from the enlargement of progenitor cells in the population independent of yeast growth rate. Change in the incubation medium, hypoxia, nutrient starvation and low pH were the main factors that trigger titan cell formation, while quorum sensing factors like the initial inoculum concentration, pantothenic acid, and the quorum sensing peptide Qsp1p also impacted titan cell formation. Inhibition of ergosterol, protein and nucleic acid biosynthesis altered titan cell formation, as did serum, phospholipids and anti-capsular antibodies in our settings. We explored genetic factors important for titan cell formation using three approaches. Using H99-derivative strains with natural genetic differences, we showed that titan cell formation was dependent on LMP1 and SGF29 genes. By screening a gene deletion collection, we also confirmed that GPR4/5-RIM101, and CAC1 genes were required to generate titan cells and that the PKR1, TSP2, USV101 genes negatively regulated titan cell formation. Furthermore, analysis of spontaneous Pkr1 loss-of-function clinical isolates confirmed the important role of the Pkr1 protein as a negative regulator of titan cell formation. Through development of a standardized and robust in vitro assay, our results provide new insights into titan cell biogenesis with the identification of multiple important factors/pathways.
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Affiliation(s)
- Benjamin Hommel
- Institut Pasteur, Molecular Mycology Unit, Département de Mycologie, Paris, France
- CNRS UMR2000, Paris, France
- Laboratoire de Parasitologie-Mycologie, Hôpital Saint-Louis, Groupe Hospitalier Lariboisière, Saint-Louis, Fernand Widal, Assistance Publique-Hôpitaux de Paris (AP-HP), Paris, France
- Université Paris Diderot, Sorbonne Paris Cité, Paris, France
| | - Liliane Mukaremera
- Department of Microbiology and Immunology, University of Minnesota, Minneapolis, Minnesota, United States of America
| | - Radames J. B. Cordero
- Department of Molecular Microbiology and Immunology, Johns Hopkins Bloomberg School of Public Health, Baltimore, MD., United States of America
| | - Carolina Coelho
- Department of Molecular Microbiology and Immunology, Johns Hopkins Bloomberg School of Public Health, Baltimore, MD., United States of America
| | | | - Aude Sturny-Leclère
- Institut Pasteur, Molecular Mycology Unit, Département de Mycologie, Paris, France
- CNRS UMR2000, Paris, France
| | - Guilhem Janbon
- Institut Pasteur, Unité Biologie des ARN des Pathogènes Fongiques, Département de Mycologie, Paris, France
| | - John R. Perfect
- Division of Infectious Diseases, Department of Medicine, Duke University Medical Center, Durham, North Carolina, United States of America
| | - James A. Fraser
- Australian Infectious Diseases Research Centre, The University of Queensland, Brisbane, Queensland, Australia
| | - Arturo Casadevall
- Department of Molecular Microbiology and Immunology, Johns Hopkins Bloomberg School of Public Health, Baltimore, MD., United States of America
| | - Christina A. Cuomo
- Broad Institute of MIT and Harvard, Cambridge, Massachusetts, United States of America
| | - Françoise Dromer
- Institut Pasteur, Molecular Mycology Unit, Département de Mycologie, Paris, France
- CNRS UMR2000, Paris, France
| | - Kirsten Nielsen
- Department of Microbiology and Immunology, University of Minnesota, Minneapolis, Minnesota, United States of America
| | - Alexandre Alanio
- Institut Pasteur, Molecular Mycology Unit, Département de Mycologie, Paris, France
- CNRS UMR2000, Paris, France
- Laboratoire de Parasitologie-Mycologie, Hôpital Saint-Louis, Groupe Hospitalier Lariboisière, Saint-Louis, Fernand Widal, Assistance Publique-Hôpitaux de Paris (AP-HP), Paris, France
- Université Paris Diderot, Sorbonne Paris Cité, Paris, France
- Department of Molecular Microbiology and Immunology, Johns Hopkins Bloomberg School of Public Health, Baltimore, MD., United States of America
- * E-mail:
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15
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Lung epithelium: barrier immunity to inhaled fungi and driver of fungal-associated allergic asthma. Curr Opin Microbiol 2017; 40:8-13. [PMID: 29096195 DOI: 10.1016/j.mib.2017.10.007] [Citation(s) in RCA: 35] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2017] [Revised: 10/10/2017] [Accepted: 10/11/2017] [Indexed: 11/23/2022]
Abstract
Fungi are ubiquitous in the environment. The epithelium that lines our airways is the first point of contact with the frequent encounter of inhaled fungi. Consequently, the lung epithelium has evolved behaviors that instruct the earliest immune events to resist fungal penetration. Although the epithelium efficiently assists in immunity to invasive fungi, it also can be inappropriately triggered, to the detriment of the host, by normally innocuous fungi or fungal components. Thus, there is a tipping point of protective immunity against fungal pathogens versus inflammatory disease caused by an exuberant immune response to harmless fungal antigens. This review will discuss several aspects of barrier immunity to pulmonary fungal infection, as well as situations where fungal exposure leads to allergic asthma.
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16
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Taylor-Smith LM. Cryptococcus-Epithelial Interactions. J Fungi (Basel) 2017; 3:jof3040053. [PMID: 29371569 PMCID: PMC5753155 DOI: 10.3390/jof3040053] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2017] [Revised: 09/28/2017] [Accepted: 09/30/2017] [Indexed: 12/12/2022] Open
Abstract
The fungal pathogen, Cryptococcus neoformans, causes devastating levels of morbidity and mortality. Infections with this fungus tend to be predominantly in immunocompromised individuals, such as those with HIV. Infections initiate with inhalation of cryptococcal cells and entry of the pathogen into the lungs. The bronchial epithelial cells of the upper airway and the alveolar epithelial cells of the lower airway are likely to be the first host cells that Cryptococcus engage with. Thus the interaction of cryptococci and the respiratory epithelia will be the focus of this review. C. neoformans has been shown to adhere to respiratory epithelial cells, although if the role of the capsule is in aiding or hindering this adhesion is debatable. The epithelia are also able to react to cryptococci with the release of cytokines and chemokines to start the immune response to this invading pathogen. The activity of surfactant components that line this mucosal barrier towards Cryptococcus and the metabolic and transcriptional reaction of cryptococci when encountering epithelial cells will also be discussed.
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Affiliation(s)
- Leanne M Taylor-Smith
- Institute of Microbiology and Infection, School of Biosciences, University of Birmingham, Edgbaston, Birmingham B15 2TT, West Midlands, UK.
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17
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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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18
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Abstract
Cryptococcosis is an invasive mycosis caused by pathogenic encapsulated yeasts in the genus Cryptococcus. Cryptococcus gained prominence as a pathogen capable of widespread disease outbreaks in vulnerable populations. We have gained insight into the pathobiology of Cryptococcus, including the yeast' s capacity to adapt to environmental pressures, exploit new geographic environments, and cause disease in both immunocompromised and apparently immunocompetent hosts. Inexpensive, point-of-care testing makes diagnosis more feasible than ever. The associated worldwide burden and mortality remains unacceptably high. Novel screening strategies and preemptive therapy offer promise at making a sustained and much needed impact on this sugar-coated opportunistic mycosis.
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Affiliation(s)
- Eileen K Maziarz
- Division of Infectious Diseases and International Health, Department of Medicine, Duke University Medical Center, DUMC Box 102359, 315 Trent Drive, Durham, NC 27710, USA.
| | - John R Perfect
- Division of Infectious Diseases and International Health, Department of Medicine, Duke University Medical Center, DUMC Box 102359, 315 Trent Drive, Durham, NC 27710, USA
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19
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Heyen L, Müller U, Siegemund S, Schulze B, Protschka M, Alber G, Piehler D. Lung epithelium is the major source of IL-33 and is regulated by IL-33-dependent and IL-33-independent mechanisms in pulmonary cryptococcosis. Pathog Dis 2016; 74:ftw086. [DOI: 10.1093/femspd/ftw086] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 09/01/2016] [Indexed: 01/08/2023] Open
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20
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Carreto-Binaghi LE, Aliouat EM, Taylor ML. Surfactant proteins, SP-A and SP-D, in respiratory fungal infections: their role in the inflammatory response. Respir Res 2016; 17:66. [PMID: 27250970 PMCID: PMC4888672 DOI: 10.1186/s12931-016-0385-9] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2015] [Accepted: 05/25/2016] [Indexed: 12/20/2022] Open
Abstract
Pulmonary surfactant is a complex fluid that comprises phospholipids and four proteins (SP-A, SP-B, SP-C, and SP-D) with different biological functions. SP-B, SP-C, and SP-D are essential for the lungs’ surface tension function and for the organization, stability and metabolism of lung parenchyma. SP-A and SP-D, which are also known as pulmonary collectins, have an important function in the host’s lung immune response; they act as opsonins for different pathogens via a C-terminal carbohydrate recognition domain and enhance the attachment to phagocytic cells or show their own microbicidal activity by increasing the cellular membrane permeability. Interactions between the pulmonary collectins and bacteria or viruses have been extensively studied, but this is not the same for fungal pathogens. SP-A and SP-D bind glucan and mannose residues from fungal cell wall, but there is still a lack of information on their binding to other fungal carbohydrate residues. In addition, both their relation with immune cells for the clearance of these pathogens and the role of surfactant proteins’ regulation during respiratory fungal infections remain unknown. Here we highlight the relevant findings associated with SP-A and SP-D in those respiratory mycoses where the fungal infective propagules reach the lungs by the airways.
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Affiliation(s)
- Laura Elena Carreto-Binaghi
- Laboratorio de Inmunología de Hongos, Unidad de Micología, Departamento de Microbiología-Parasitología, Facultad de Medicina, Universidad Nacional Autónoma de México (UNAM); Circuito Interior, Ciudad Universitaria, Av. Universidad 3000, México, D.F., 04510, Mexico
| | - El Moukhtar Aliouat
- Laboratoire Biologie et Diversité des Pathogènes Eucaryotes Emergents, CIIL Institut Pasteur de Lille, Bâtiment Guérin, 1 rue du Professeur Calmette, Lille, France
| | - Maria Lucia Taylor
- Laboratorio de Inmunología de Hongos, Unidad de Micología, Departamento de Microbiología-Parasitología, Facultad de Medicina, Universidad Nacional Autónoma de México (UNAM); Circuito Interior, Ciudad Universitaria, Av. Universidad 3000, México, D.F., 04510, Mexico.
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21
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Zhang M, Sun D, Shi M. Dancing cheek to cheek: Cryptococcus neoformans and phagocytes. SPRINGERPLUS 2015; 4:410. [PMID: 26266081 PMCID: PMC4531118 DOI: 10.1186/s40064-015-1192-3] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/07/2015] [Accepted: 07/29/2015] [Indexed: 01/04/2023]
Abstract
Meningoencephalitis caused by Cryptococcus neoformans (Cn) has become one of the leading causes of mortality in AIDS patients. Understanding the interactions between Cn and phagocytes is fundamental in exploring the pathogenicity of cryptococcal meningoencephalitis. Cn may be extracellular or contained in the monocytes, macrophages, neutrophils, dendritic cells and even endothelial cells. The internalized Cn may proliferate inside the host cells, or cause the lysis of host cells, or leave the host cells via non-lytic exocytosis, or even hijack the host cells (Trojan horse) for the brain dissemination, which are regulated by microbe factors and also immune molecules. Coexistence of protective and deleterious roles of phagocytes in the progression of cryptococcosis warrant further investigation.
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Affiliation(s)
- Mingshun Zhang
- Division of Immunology, Virginia-Maryland Regional College of Veterinary Medicine, University of Maryland, College Park, MD USA ; Department of Immunology, Nanjing Medical University, Nanjing, Jiangsu China
| | - Donglei Sun
- Division of Immunology, Virginia-Maryland Regional College of Veterinary Medicine, University of Maryland, College Park, MD USA
| | - Meiqing Shi
- Division of Immunology, Virginia-Maryland Regional College of Veterinary Medicine, University of Maryland, College Park, MD USA
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22
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23
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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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24
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Abstract
Cryptococcus species are fungal pathogens that are a leading cause of mortality. Initial inoculation is through the pulmonary route and, if disseminated, results in severe invasive infection including meningoencephalitis. Macrophages are the dominant phagocytic cell that interacts with Cryptococcus. Emerging theories suggest that Cryptococcus microevolution in macrophages is linked to survival and virulence within the host. In addition, Cryptococcus elaborates virulence factors as well as usurps host machinery to establish macrophage activation states that are permissive to intracellular survival and replication. In this review, we provide an update of the recent findings pertaining to macrophage interaction with Cryptococcus and focus on new avenues for biomedical research.
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25
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Impact of surfactant protein D, interleukin-5, and eosinophilia on Cryptococcosis. Infect Immun 2013; 82:683-93. [PMID: 24478083 DOI: 10.1128/iai.00855-13] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
Abstract
Cryptococcus neoformans is an opportunistic fungal pathogen that initiates infection following inhalation. As a result, the pulmonary immune response provides a first line of defense against C. neoformans. Surfactant protein D (SP-D) is an important regulator of pulmonary immune responses and is typically host protective against bacterial and viral respiratory infections. However, SP-D is not protective against C. neoformans. This is evidenced by previous work from our laboratory demonstrating that SP-D-deficient mice infected with C. neoformans have a lower fungal burden and live longer than wild-type (WT) control animals. We hypothesized that SP-D alters susceptibility to C. neoformans by dysregulating the innate pulmonary immune response following infection. Thus, inflammatory cells and cytokines were compared in the bronchoalveolar lavage fluid from WT and SP-D(-/-) mice after C. neoformans infection. Postinfection, mice lacking SP-D have reduced eosinophil infiltration and interleukin-5 (IL-5) in lung lavage fluid. To further explore the interplay of SP-D, eosinophils, and IL-5, mice expressing altered levels of eosinophils and/or IL-5 were infected with C. neoformans to assess the role of these innate immune mediators. IL-5-overexpressing mice have increased pulmonary eosinophilia and are more susceptible to C. neoformans infection than WT mice. Furthermore, susceptibility of SP-D(-/-) mice to C. neoformans infection could be restored to the level of WT mice by increasing IL-5 and eosinophils by crossing the IL-5-overexpressing mice with SP-D(-/-) mice. Together, these studies support the conclusion that SP-D increases susceptibility to C. neoformans infection by promoting C. neoformans-driven pulmonary IL-5 and eosinophil infiltration.
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26
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Sabiiti W, May RC. Mechanisms of infection by the human fungal pathogen Cryptococcus neoformans. Future Microbiol 2013; 7:1297-313. [PMID: 23075448 DOI: 10.2217/fmb.12.102] [Citation(s) in RCA: 61] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
Brain infection by the fungus Cryptococcus neoformans results in inflammation of the meninges and brain parenchyma, a condition known as meningoencephalitis. One million people are estimated to suffer cryptococcal meningitis globally and >60% of these cases die within 3 months of diagnosis. Humans are believed to contract infection by inhalation of spores or dried yeast cells, which subsequently colonize the lung tissue. In the lungs, cryptococci may be cleared by the lung phagocytes, stay latent, cause pulmonary infection and/or disseminate to other body parts, preferentially the brain, culminating in cryptococcal meningoencephalitis. In this review, we discuss the pathogenesis of C. neoformans from the environment to the brain, the current understanding of the mechanisms of cryptococcal transmission into the brain and cryptococcal meningitis. We also give an insight into future cryptococcosis research and the development of novel therapies.
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Affiliation(s)
- Wilber Sabiiti
- Infection & Immunity, Clinical Sciences Division, St Georges' University of London, London SW17 0RE, UK
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27
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Johnston SA, May RC. Cryptococcusinteractions with macrophages: evasion and manipulation of the phagosome by a fungal pathogen. Cell Microbiol 2012; 15:403-11. [DOI: 10.1111/cmi.12067] [Citation(s) in RCA: 111] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2012] [Revised: 10/28/2012] [Accepted: 10/29/2012] [Indexed: 01/19/2023]
Affiliation(s)
| | - Robin C. May
- Institute of Microbiology and Infection; School of Biosciences; University of Birmingham; Birmingham; B15 2TT; UK
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