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Al-Huthaifi AM, Radman BA, Al-Alawi AA, Mahmood F, Liu TB. Mechanisms and Virulence Factors of Cryptococcus neoformans Dissemination to the Central Nervous System. J Fungi (Basel) 2024; 10:586. [PMID: 39194911 DOI: 10.3390/jof10080586] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2024] [Revised: 07/31/2024] [Accepted: 08/15/2024] [Indexed: 08/29/2024] Open
Abstract
Cryptococcosis is a prevalent fungal infection of the central nervous system (CNS) caused by Cryptococcus neoformans, a yeast with a polysaccharide capsule in the basidiomycete group. Normally, C. neoformans infects the respiratory tract and then breaches the blood-brain barrier (BBB), leading to meningitis or meningoencephalitis, which leads to hundreds of thousands of deaths each year. Although the mechanism by which C. neoformans infiltrates the BBB to invade the brain has yet to be fully understood, research has revealed that C. neoformans can cross the BBB using transcellular penetration, paracellular traversal, and infected phagocytes (the "Trojan horse" mechanism). The secretion of multiple virulence factors by C. neoformans is crucial in facilitating the spread of infection after breaching the BBB and causing brain infections. Extensive research has shown that various virulence factors play a significant role in the dissemination of infection beyond the lungs. This review explores the mechanisms of C. neoformans entering the CNS and explains how it bypasses the BBB. Additionally, it aims to understand the interplay between the regulatory mechanisms and virulence factors of C. neoformans.
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Affiliation(s)
| | - Bakeel A Radman
- Cancer Center, Integrated Hospital of Traditional Chinese Medicine, Southern Medical University, Guangzhou 510315, China
| | | | - Fawad Mahmood
- Medical Research Institute, Southwest University, Chongqing 400715, China
| | - Tong-Bao Liu
- Medical Research Institute, Southwest University, Chongqing 400715, China
- Jinfeng Laboratory, Chongqing 401329, China
- Engineering Research Center for Cancer Biomedical and Translational Medicine, Southwest University, Chongqing 400715, China
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2
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Davis JM. A deep cut into early cryptococcal pathogenesis. mBio 2024; 15:e0065724. [PMID: 38975784 PMCID: PMC11323497 DOI: 10.1128/mbio.00657-24] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 07/09/2024] Open
Abstract
Dissemination from one organ system to another is common to many pathogens and often the key process separating simple illness from fatal infection. The pathogenic Cryptococcus species offer a prime example. Cryptococcal infection is thought to begin in the lungs, as a mild or asymptomatic pneumonia. However, bloodborne dissemination from the lungs to the brain is responsible for the most devastating forms of infection. As with other disseminating infections, the transition likely depends on rare but crucial events, such as the crossing of a tissue barrier. By their nature, these events are difficult to study. Francis et al. (mBio 15:e03078-23, 2024, https://doi.org/10.1128/mbio.03078-23) have addressed this difficulty by developing a powerful imaging pipeline to scan through unprecedented volumes of tissue from mice infected with Cryptococcus at multiple stages of infection. Their observations challenge some of our basic assumptions about cryptococcal pathogenesis, including when and how the organism reaches the bloodstream and the central nervous system.
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Affiliation(s)
- J. Muse Davis
- Stead Family Department of Pediatrics, Carver College of Medicine, University of Iowa, Iowa City, Iowa, USA
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3
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Francis VI, Liddle C, Camacho E, Kulkarni M, Junior SRS, Harvey JA, Ballou ER, Thomson DD, Brown GD, Hardwick JM, Casadevall A, Witton J, Coelho C. Cryptococcus neoformans rapidly invades the murine brain by sequential breaching of airway and endothelial tissues barriers, followed by engulfment by microglia. mBio 2024; 15:e0307823. [PMID: 38511961 PMCID: PMC11005363 DOI: 10.1128/mbio.03078-23] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2023] [Accepted: 02/29/2024] [Indexed: 03/22/2024] Open
Abstract
Cryptococcus neoformans causes lethal meningitis and accounts for approximately 10%-15% of AIDS-associated deaths worldwide. There are major gaps in our understanding of how this fungus invades the mammalian brain. To investigate the dynamics of C. neoformans tissue invasion, we mapped fungal localization and host cell interactions in infected brain, lung, and upper airways using mouse models of systemic and airway infection. To enable this, we developed an in situ imaging pipeline capable of measuring large volumes of tissue while preserving anatomical and cellular information by combining thick tissue sections, tissue clarification, and confocal imaging. We confirm high fungal burden in mouse upper airway after nasal inoculation. Yeast in turbinates were frequently titan cells, with faster kinetics than reported in mouse lungs. Importantly, we observed one instance of fungal cells enmeshed in lamina propria of the upper airways, suggesting penetration of airway mucosa as a possible route of tissue invasion and dissemination to the bloodstream. We extend previous literature positing bloodstream dissemination of C. neoformans, by finding viable fungi in the bloodstream of mice a few days after intranasal infection. As early as 24 h post systemic infection, the majority of C. neoformans cells traversed the blood-brain barrier, and were engulfed or in close proximity to microglia. Our work presents a new method for investigating microbial invasion, establishes that C. neoformans can breach multiple tissue barriers within the first days of infection, and demonstrates microglia as the first cells responding to C. neoformans invasion of the brain.IMPORTANCECryptococcal meningitis causes 10%-15% of AIDS-associated deaths globally. Still, brain-specific immunity to cryptococci is a conundrum. By employing innovative imaging, this study reveals what occurs during the first days of infection in brain and in airways. We found that titan cells predominate in upper airways and that cryptococci breach the upper airway mucosa, which implies that, at least in mice, the upper airways are a site for fungal dissemination. This would signify that mucosal immunity of the upper airway needs to be better understood. Importantly, we also show that microglia, the brain-resident macrophages, are the first responders to infection, and microglia clusters are formed surrounding cryptococci. This study opens the field to detailed molecular investigations on airway immune response, how fungus traverses the blood-brain barrier, how microglia respond to infection, and ultimately how microglia monitor the blood-brain barrier to preserve brain function.
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Affiliation(s)
- Vanessa I. Francis
- MRC Centre for Medical Mycology at University of Exeter, University of Exeter, Exeter, United Kingdom
- Faculty of Health and Life Sciences, University of Exeter, Exeter, United Kingdom
| | - Corin Liddle
- Bioimaging Facility, University of Exeter, Exeter, United Kingdom
| | - Emma Camacho
- Johns Hopkins Bloomberg School of Public Health, Baltimore, Maryland, USA
| | - Madhura Kulkarni
- Johns Hopkins Bloomberg School of Public Health, Baltimore, Maryland, USA
| | | | - Jamie A. Harvey
- MRC Centre for Medical Mycology at University of Exeter, University of Exeter, Exeter, United Kingdom
| | - Elizabeth R. Ballou
- MRC Centre for Medical Mycology at University of Exeter, University of Exeter, Exeter, United Kingdom
| | - Darren D. Thomson
- MRC Centre for Medical Mycology at University of Exeter, University of Exeter, Exeter, United Kingdom
| | - Gordon D. Brown
- MRC Centre for Medical Mycology at University of Exeter, University of Exeter, Exeter, United Kingdom
- Faculty of Health and Life Sciences, University of Exeter, Exeter, United Kingdom
| | - J. Marie Hardwick
- Johns Hopkins Bloomberg School of Public Health, Baltimore, Maryland, USA
| | - Arturo Casadevall
- Johns Hopkins Bloomberg School of Public Health, Baltimore, Maryland, USA
| | - Jonathan Witton
- Faculty of Health and Life Sciences, University of Exeter, Exeter, United Kingdom
| | - Carolina Coelho
- MRC Centre for Medical Mycology at University of Exeter, University of Exeter, Exeter, United Kingdom
- Faculty of Health and Life Sciences, University of Exeter, Exeter, United Kingdom
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4
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Zhou Y, Huang Y, Yang C, Zang X, Deng H, Liu J, Zhao E, Tian T, Pan L, Xue X. The pathways and the mechanisms by which Cryptococcus enters the brain. Mycology 2024; 15:345-359. [PMID: 39247889 PMCID: PMC11376299 DOI: 10.1080/21501203.2023.2295409] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2023] [Accepted: 12/11/2023] [Indexed: 09/10/2024] Open
Abstract
Generally, Cryptococcus initially infects the respiratory tract, but can spread, eventually crossing the blood-brain barrier (BBB) and causing meningitis or meningoencephalitis. Specifically, Cryptococcus invades the vascular endothelial cells of the BBB, from which it enters the brain. The main mechanisms through which Cryptococcus crosses the BBB are transcellular traversal, the paracellular pathway, and via Trojan horse. In this paper, the mechanisms by which Cryptococcus crosses the BBB were explained in detail. In addition to pathways of entry to the brain, this paper presents a discussion on some rare cryptococcal infections and provides some insights for future research directions.
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Affiliation(s)
- Yangyu Zhou
- Department of Respiratory and Critical Care, Emergency and Critical Care Medical Center, Beijing Shijitan Hospital, Capital Medical University, Beijing, China
| | - Yemei Huang
- Department of Respiratory and Critical Care, Emergency and Critical Care Medical Center, Beijing Shijitan Hospital, Capital Medical University, Beijing, China
| | - Chen Yang
- Department of Respiratory and Critical Care, Weifang Medical College, Weifang, China
| | - Xuelei Zang
- Department of Respiratory and Critical Care, Emergency and Critical Care Medical Center, Beijing Shijitan Hospital, Capital Medical University, Beijing, China
| | - Hengyu Deng
- Department of Laboratory Medicine, Chinese PLA General Hospital, the First Medical Centre, Beijing, China
| | - Jing Liu
- Department of Laboratory Medicine, Chinese PLA General Hospital, the First Medical Centre, Beijing, China
| | - Enqi Zhao
- Department of Respiratory and Critical Care, Emergency and Critical Care Medical Center, Beijing Shijitan Hospital, Capital Medical University, Beijing, China
| | - Tingyue Tian
- Department of Respiratory and Critical Care, Emergency and Critical Care Medical Center, Beijing Shijitan Hospital, Capital Medical University, Beijing, China
| | - Lei Pan
- Department of Respiratory and Critical Care, Emergency and Critical Care Medical Center, Beijing Shijitan Hospital, Capital Medical University, Beijing, China
| | - Xinying Xue
- Department of Respiratory and Critical Care, Emergency and Critical Care Medical Center, Beijing Shijitan Hospital, Capital Medical University, Beijing, China
- Department of Laboratory Medicine, Chinese PLA General Hospital, the First Medical Centre, Beijing, China
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5
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Li X, Xu J, Lin X, Lin Q, Yu T, Chen L, Chen L, Huang X, Zhang X, Chen G, Xu L. Macrophages-derived exo-miR-4449 induced by Cryptococcus affects HUVEC permeability and promotes pyroptosis in BEAS-2B via the HIC1 pathway. Cytokine 2024; 173:156441. [PMID: 37995394 DOI: 10.1016/j.cyto.2023.156441] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2023] [Revised: 10/27/2023] [Accepted: 11/10/2023] [Indexed: 11/25/2023]
Abstract
Macrophages have recently been discovered to assume a significant role in the progression of cryptococcosis. However, the potential involvement of macrophage-derived exosomes in the pathogenesis of cryptococcosis remains uncertain. In this study, we investigated the changes of microRNAs in macrophage exosomes (exo-miRNAs) in cryptococcal infections and the role of markedly altered exo-miRNAs in the modulation of Human Umbilical Vein Endothelial Cells (HUVEC) permeability and ROS accumulation and pyroptosis in Human Bronchial Epithelioid Cells (BEAS-2B). Techniques such as microarray analysis and real-time quantitative PCR were used to detect different exo-miRNAs and to screen for the most highly expressed exo-miRNAs. Then its mimics were transfected into HUVEC to study its effect on the monolayer permeability of HUVEC. Finally, the relationship between this exo-miRNAs and the ROS accumulation and pyroptosis was verified by bioinformatics analysis. The results showed that five exo-miRNAs were overexpressed and two exo-miRNAs were reduced, among which, exo-miR-4449 was expressed at the highest level. Exo-miR-4449 could be internalized by HUVEC and enhanced its monolayer permeability. Moreover, exo-miR-4449 was found to promote ROS accumulation and pyroptosis in BEAS-2B through HIC1 pathway. Thus, exo-miR-4449 plays an important role in the pathogenesis of cryptococcosis and holds promise as a significant biomarker for treatment.
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Affiliation(s)
- Xiaohua Li
- Department of Pulmonary and Critical Care Medicine, Fuzhou No. 1 Hospital Affiliated with Fujian Medical University, Fuzhou 350009, China.
| | - Junping Xu
- Department of Pulmonary and Critical Care Medicine, Fuzhou No. 1 Hospital Affiliated with Fujian Medical University, Fuzhou 350009, China.
| | - Xin Lin
- Department of Pulmonary and Critical Care Medicine, Fuzhou No. 1 Hospital Affiliated with Fujian Medical University, Fuzhou 350009, China.
| | - Qiong Lin
- Department of Pulmonary and Critical Care Medicine, Fuzhou No. 1 Hospital Affiliated with Fujian Medical University, Fuzhou 350009, China.
| | - Tianxing Yu
- Department of Pulmonary and Critical Care Medicine, Fuzhou No. 1 Hospital Affiliated with Fujian Medical University, Fuzhou 350009, China.
| | - Lin Chen
- Department of Pulmonary and Critical Care Medicine, Fuzhou No. 1 Hospital Affiliated with Fujian Medical University, Fuzhou 350009, China.
| | - Lifang Chen
- Department of Pulmonary and Critical Care Medicine, Fuzhou No. 1 Hospital Affiliated with Fujian Medical University, Fuzhou 350009, China.
| | - Xiaoqing Huang
- Department of Pulmonary and Critical Care Medicine, Fuzhou No. 1 Hospital Affiliated with Fujian Medical University, Fuzhou 350009, China.
| | - Xueping Zhang
- Department of Pulmonary and Critical Care Medicine, Fuzhou No. 1 Hospital Affiliated with Fujian Medical University, Fuzhou 350009, China.
| | - Geng Chen
- Nursing Department, Fuzhou No. 1 Hospital Affiliated with Fujian Medical University, Fuzhou 350009, China.
| | - Liyu Xu
- Department of Pulmonary and Critical Care Medicine, Fuzhou No. 1 Hospital Affiliated with Fujian Medical University, Fuzhou 350009, China.
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6
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Francis VI, Liddle C, Camacho E, Kulkarni M, Junior SRS, Harvey JA, Ballou ER, Thomson DD, Hardwick JM, Casadevall A, Witton J, Coelho C. Cryptococcus neoformans rapidly invades the murine brain by sequential breaching of airway and endothelial tissues barriers, followed by engulfment by microglia. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.11.13.564824. [PMID: 38014111 PMCID: PMC10680653 DOI: 10.1101/2023.11.13.564824] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/29/2023]
Abstract
The fungus Cryptococcus neoformans causes lethal meningitis in humans with weakened immune systems and is estimated to account for 10-15% of AIDS-associated deaths worldwide. There are major gaps in our understanding of how this environmental fungus evades the immune system and invades the mammalian brain before the onset of overt symptoms. To investigate the dynamics of C. neoformans tissue invasion, we mapped early fungal localisation and host cell interactions at early times in infected brain, lung, and upper airways using mouse models of systemic and airway infection. To enable this, we developed an in situ imaging pipeline capable of measuring large volumes of tissue while preserving anatomical and cellular information by combining thick tissue sections, tissue clarification, and confocal imaging. Made possible by these techniques, we confirm high fungal burden in mouse upper airway turbinates after nasal inoculation. Surprisingly, most yeasts in turbinates were titan cells, indicating this microenvironment enables titan cell formation with faster kinetics than reported in mouse lungs. Importantly, we observed one instance of fungal cells enmeshed in lamina propria of upper airways, suggesting penetration of airway mucosa as a possible route of tissue invasion and dissemination to the bloodstream. We extend previous literature positing bloodstream dissemination of C. neoformans, via imaging C. neoformans within blood vessels of mouse lungs and finding viable fungi in the bloodstream of mice a few days after intranasal infection, suggesting that bloodstream access can occur via lung alveoli. In a model of systemic cryptococcosis, we show that as early as 24 h post infection, majority of C. neoformans cells traversed the blood-brain barrier, and are engulfed or in close proximity to microglia. Our work establishes that C. neoformans can breach multiple tissue barriers within the first days of infection. This work presents a new method for investigating cryptococcal invasion mechanisms and demonstrates microglia as the primary cells responding to C. neoformans invasion.
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Affiliation(s)
- Vanessa I Francis
- MRC Centre for Medical Mycology at University of Exeter, University of Exeter, Exeter, EX4 4QD, UK
- Faculty of Health and Life Sciences, University of Exeter, EX4 4QD, UK
| | - Corin Liddle
- Bioimaging Facility, University of Exeter, Exeter, EX4 4QD, UK
| | - Emma Camacho
- Johns Hopkins Bloomberg School of Public Health, Baltimore, Maryland, USA
| | - Madhura Kulkarni
- Johns Hopkins Bloomberg School of Public Health, Baltimore, Maryland, USA
| | - Samuel R S Junior
- Johns Hopkins Bloomberg School of Public Health, Baltimore, Maryland, USA
| | - Jamie A Harvey
- MRC Centre for Medical Mycology at University of Exeter, University of Exeter, Exeter, EX4 4QD, UK
| | - Elizabeth R Ballou
- MRC Centre for Medical Mycology at University of Exeter, University of Exeter, Exeter, EX4 4QD, UK
| | - Darren D Thomson
- MRC Centre for Medical Mycology at University of Exeter, University of Exeter, Exeter, EX4 4QD, UK
| | - J Marie Hardwick
- Johns Hopkins Bloomberg School of Public Health, Baltimore, Maryland, USA
| | - Arturo Casadevall
- Johns Hopkins Bloomberg School of Public Health, Baltimore, Maryland, USA
| | - Jonathan Witton
- Faculty of Health and Life Sciences, University of Exeter, EX4 4QD, UK
| | - Carolina Coelho
- MRC Centre for Medical Mycology at University of Exeter, University of Exeter, Exeter, EX4 4QD, UK
- Faculty of Health and Life Sciences, University of Exeter, EX4 4QD, UK
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de Andrade IB, Alves V, Pereira L, Miranda B, Corrêa-Junior D, Galdino Figueiredo-Carvalho MH, Santos MV, Almeida-Paes R, Frases S. Effect of rapamycin on Cryptococcus neoformans: cellular organization, biophysics and virulence factors. Future Microbiol 2023; 18:1061-1075. [PMID: 37721517 DOI: 10.2217/fmb-2023-0097] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 09/19/2023] Open
Abstract
Background: Cryptococcus neoformans is an opportunistic fungal pathogen that causes infections mainly in immunosuppressed individuals, such as transplant recipients. Aims: This study investigated the effects of rapamycin, an immunosuppressant drug, on the cellular organization, biophysical characteristics, and main virulence factors of C. neoformans. Methods: Morphological, structural, physicochemical and biophysical analyses of cells and secreted polysaccharides of the reference H99 C. neoformans strain were investigated under the effect of subinhibitory concentrations of rapamycin. Results: Rapamycin at a minimum inhibitory concentration of 2.5 μM reduced C. neoformans cell viability by 53%, decreased capsule, increased cell size, chitin and lipid body formation, and changed peptidase and urease activity. Conclusion: Further studies are needed to assess how rapamycin affects the virulence factors and pathogenicity of C. neoformans.
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Affiliation(s)
- Iara Bastos de Andrade
- Laboratório de Biofísica de Fungos, Instituto de Biofísica Carlos Chagas Filho, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brazil
| | - Vinicius Alves
- Laboratório de Biofísica de Fungos, Instituto de Biofísica Carlos Chagas Filho, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brazil
| | - Luiza Pereira
- Laboratório de Biofísica de Fungos, Instituto de Biofísica Carlos Chagas Filho, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brazil
| | - Bruna Miranda
- Laboratório de Biofísica de Fungos, Instituto de Biofísica Carlos Chagas Filho, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brazil
| | - Dario Corrêa-Junior
- Laboratório de Biofísica de Fungos, Instituto de Biofísica Carlos Chagas Filho, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brazil
| | | | - Marcos Vinicius Santos
- Laboratório de Micologia, Instituto Nacional de Infectologia Evandro Chagas, Fundação Oswaldo Cruz, Rio de Janeiro, Brazil
| | - Rodrigo Almeida-Paes
- Laboratório de Micologia, Instituto Nacional de Infectologia Evandro Chagas, Fundação Oswaldo Cruz, Rio de Janeiro, Brazil
- Rede Micologia - FAPERJ, Rio de Janeiro, Brazil
| | - Susana Frases
- Laboratório de Biofísica de Fungos, Instituto de Biofísica Carlos Chagas Filho, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brazil
- Rede Micologia - FAPERJ, Rio de Janeiro, Brazil
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Andrade-Silva LE, Vilas-Boas A, Ferreira-Paim K, Andrade-Silva J, Santos DDA, Ferreira TB, Borges AS, Mora DJ, Melhem MDSC, Silva-Vergara ML. Genotyping Analysis of Cryptococcus deuterogattii and Correlation with Virulence Factors and Antifungal Susceptibility by the Clinical and Laboratory Standards Institute and the European Committee on Antifungal Susceptibility Testing Methods. J Fungi (Basel) 2023; 9:889. [PMID: 37754997 PMCID: PMC10532325 DOI: 10.3390/jof9090889] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2023] [Revised: 08/10/2023] [Accepted: 08/14/2023] [Indexed: 09/28/2023] Open
Abstract
Data about the relationship between their molecular types, virulence factors, clinical presentation, antifungal susceptibility profile, and outcome are still limited for Cryptococcus deuterogattii. This study aimed to evaluate the molecular and phenotypic characteristics of 24 C. deuterogattii isolates from the southeast region of Brazil. The molecular characterization was performed by multilocus sequence typing (MLST). The antifungal susceptibility profile was obtained according to CLSI-M27-A3 and EUCAST-EDef 7.1 methods. The virulence factors were evaluated using classic techniques. The isolates were divided into four populations. The molecular analysis suggests recombinant events in most of the groups evaluated. Resistance and susceptibility dose-dependent to fluconazole were evidenced in four isolates (16%) by EUCAST and in four isolates (16%) by CLSI methods. The agreement at ±two dilutions for both methods was 100% for itraconazole, ketoconazole, and voriconazole, 96% for amphotericin B, and 92% for fluconazole. Significant differences in virulence factor expression and antifungal susceptibility to itraconazole and amphotericin B were found. The mixed infection could be suggested by the presence of variable sequence types, differences in virulence factor production, and decreased antifungal susceptibility in two isolates from the same patient. The data presented herein corroborate previous reports about the molecular diversity of C. deuterogattii around the world.
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Affiliation(s)
- Leonardo Euripedes Andrade-Silva
- Infectious Diseases Unit, Internal Medicine Department, Federal University of Triangulo Mineiro, Uberaba 38001-170, MG, Brazil; (A.V.-B.); (K.F.-P.); (J.A.-S.); (T.B.F.); (M.L.S.-V.)
| | - Anderson Vilas-Boas
- Infectious Diseases Unit, Internal Medicine Department, Federal University of Triangulo Mineiro, Uberaba 38001-170, MG, Brazil; (A.V.-B.); (K.F.-P.); (J.A.-S.); (T.B.F.); (M.L.S.-V.)
| | - Kennio Ferreira-Paim
- Infectious Diseases Unit, Internal Medicine Department, Federal University of Triangulo Mineiro, Uberaba 38001-170, MG, Brazil; (A.V.-B.); (K.F.-P.); (J.A.-S.); (T.B.F.); (M.L.S.-V.)
| | - Juliana Andrade-Silva
- Infectious Diseases Unit, Internal Medicine Department, Federal University of Triangulo Mineiro, Uberaba 38001-170, MG, Brazil; (A.V.-B.); (K.F.-P.); (J.A.-S.); (T.B.F.); (M.L.S.-V.)
| | - Daniel de Assis Santos
- Microbiology Department, Biological Sciences Institute, Federal University of Minas Gerais, Belo Horizonte 31270-901, MG, Brazil;
| | - Thatiana Bragine Ferreira
- Infectious Diseases Unit, Internal Medicine Department, Federal University of Triangulo Mineiro, Uberaba 38001-170, MG, Brazil; (A.V.-B.); (K.F.-P.); (J.A.-S.); (T.B.F.); (M.L.S.-V.)
| | - Aercio Sebastião Borges
- Infectious Diseases Unit, Internal Medicine Department, Federal University of Uberlândia, Uberlândia 38496-017, MG, Brazil
| | - Delio Jose Mora
- Center of Health Sciences, Federal University of Sul da Bahia, Teixeira de Freitas 85866-000, BA, Brazil;
| | | | - Mario Léon Silva-Vergara
- Infectious Diseases Unit, Internal Medicine Department, Federal University of Triangulo Mineiro, Uberaba 38001-170, MG, Brazil; (A.V.-B.); (K.F.-P.); (J.A.-S.); (T.B.F.); (M.L.S.-V.)
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9
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Cryptococcal Immune Reconstitution Inflammatory Syndrome: From Clinical Studies to Animal Experiments. Microorganisms 2022; 10:microorganisms10122419. [PMID: 36557672 PMCID: PMC9780901 DOI: 10.3390/microorganisms10122419] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2022] [Revised: 12/05/2022] [Accepted: 12/05/2022] [Indexed: 12/12/2022] Open
Abstract
Cryptococcus neoformans is an encapsulated pathogenic fungus that initially infects the lung but can migrate to the central nervous system (CNS), resulting in meningoencephalitis. The organism causes the CNS infection primarily in immunocompromised individuals including HIV/AIDS patients, but also, rarely, in immunocompetent individuals. In HIV/AIDS patients, limited inflammation in the CNS, due to impaired cellular immunity, cannot efficiently clear a C. neoformans infection. Antiretroviral therapy (ART) can rapidly restore cellular immunity in HIV/AIDS patients. Paradoxically, ART induces an exaggerated inflammatory response, termed immune reconstitution inflammatory syndrome (IRIS), in some HIV/AIDS patients co-infected with C. neoformans. A similar excessive inflammation, referred to as post-infectious inflammatory response syndrome (PIIRS), is also frequently seen in previously healthy individuals suffering from cryptococcal meningoencephalitis. Cryptococcal IRIS and PIIRS are life-threatening complications that kill up to one-third of affected people. In this review, we summarize the inflammatory responses in the CNS during HIV-associated cryptococcal meningoencephalitis. We overview the current understanding of cryptococcal IRIS developed in HIV/AIDS patients and cryptococcal PIIRS occurring in HIV-uninfected individuals. We also describe currently available animal models that closely mimic aspects of cryptococcal IRIS observed in HIV/AIDS patients.
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10
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Cryptococcus neoformans Infection in the Central Nervous System: The Battle between Host and Pathogen. J Fungi (Basel) 2022; 8:jof8101069. [PMID: 36294634 PMCID: PMC9605252 DOI: 10.3390/jof8101069] [Citation(s) in RCA: 22] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2022] [Revised: 09/28/2022] [Accepted: 10/07/2022] [Indexed: 11/17/2022] Open
Abstract
Cryptococcus neoformans (C. neoformans) is a pathogenic fungus with a global distribution. Humans become infected by inhaling the fungus from the environment, and the fungus initially colonizes the lungs. If the immune system fails to contain C. neoformans in the lungs, the fungus can disseminate to the blood and invade the central nervous system, resulting in fatal meningoencephalitis particularly in immunocompromised individuals including HIV/AIDS patients. Following brain invasion, C. neoformans will encounter host defenses involving resident as well as recruited immune cells in the brain. To overcome host defenses, C. neoformans possesses multiple virulence factors capable of modulating immune responses. The outcome of the interactions between the host and C. neoformans will determine the disease progression. In this review, we describe the current understanding of how C. neoformans migrates to the brain across the blood–brain barrier, and how the host immune system responds to the invading organism in the brain. We will also discuss the virulence factors that C. neoformans uses to modulate host immune responses.
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11
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Gutierrez-Gongora D, Geddes-McAlister J. Peptidases: promising antifungal targets of the human fungal pathogen, Cryptococcus neoformans. Facets (Ott) 2022. [DOI: 10.1139/facets-2021-0157] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Cryptococcus neoformans is a globally important fungal pathogen, primarily inflicting disease on immunocompromised individuals. The widespread use of antifungal agents in medicine and agriculture supports the development of antifungal resistance through evolution, and the emergence of new strains with intrinsic resistance drives the need for new therapeutics. For C. neoformans, the production of virulence factors, including extracellular peptidases (e.g., CnMpr-1 and May1) with mechanistic roles in tissue invasion and fungal survival, constitute approximately 2% of the fungal proteome and cover five classes of enzymes. Given their role in fungal virulence, peptidases represent promising targets for anti-virulence discovery in the development of new approaches against C. neoformans. Additionally, intracellular peptidases, which are involved in resistance mechanisms against current treatment options (e.g., azole drugs), as well as capsule biosynthesis and elaboration of virulence factors, present additional opportunities to combat the pathogen. In this review, we highlight key cryptococcal peptidases with defined or predicted roles in fungal virulence and assess sequence alignments against their human homologs. With this information, we define the feasibility of the select peptidases as “druggable” targets for inhibition, representing prospective therapeutic options against the deadly fungus.
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Affiliation(s)
- Davier Gutierrez-Gongora
- The Department of Molecular and Cellular Biology, University of Guelph, Guelph, Ontario N1G 2W1, Canada
- Centro de Estudio de Proteínas, Facultad de Biología, Universidad de La Habana, La Habana, Cuba
| | - Jennifer Geddes-McAlister
- The Department of Molecular and Cellular Biology, University of Guelph, Guelph, Ontario N1G 2W1, Canada
- Canadian Proteomics and Artificial Intelligence Research and Training Consortium
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Chen Y, Li C, Sun D, Strickland AB, Liu G, Shi M. Quantitative analysis reveals internalisation of Cryptococcus neoformans by brain endothelial cells in vivo. Cell Microbiol 2021; 23:e13330. [PMID: 33745221 DOI: 10.1111/cmi.13330] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2020] [Revised: 03/16/2021] [Accepted: 03/17/2021] [Indexed: 12/12/2022]
Abstract
Migration of Cryptococcus neoformans from the blood to the brain parenchyma is crucial to cause fatal meningoencephalitis. Although mechanisms involved in brain migration of C. neoformans have been widely studied in vitro, less is known about how the fungus crosses the blood-brain barrier (BBB) in vivo. This is in part because of the lack of an approach to quantitatively analyse the dynamics of fungal transmigration into the brain across the BBB in vivo. In this study, we report a novel approach to quantitatively analyse the interactions between C. neoformans and brain endothelial cells in a mouse model using flow cytometry. Using this system, we show that C. neoformans was internalised by brain endothelial cells in vivo and that mice infected with acapsular or heat-killed C. neoformans yeast cells displayed a lower frequency of brain endothelial cells containing the yeast cell compared to mice infected with wild-type or viable yeast cells, respectively. We further demonstrate that brain endothelial cells were invaded by serotype A strain (H99 strain) at a higher rate compared to serotype D strain (52D strain). Our experiments established that internalisation of C. neoformans by brain endothelial cells occurred in vivo and offered a powerful approach to quantitatively analyse fungal migration into the brain.
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Affiliation(s)
- Yanli Chen
- Division of Immunology, Virginia-Maryland College of Veterinary Medicine and Maryland Pathogen Research Institute, University of Maryland, College Park, Maryland, USA
| | - Chang Li
- Division of Immunology, Virginia-Maryland College of Veterinary Medicine and Maryland Pathogen Research Institute, University of Maryland, College Park, Maryland, USA
| | - Donglei Sun
- Division of Immunology, Virginia-Maryland College of Veterinary Medicine and Maryland Pathogen Research Institute, University of Maryland, College Park, Maryland, USA
| | - Ashley B Strickland
- Division of Immunology, Virginia-Maryland College of Veterinary Medicine and Maryland Pathogen Research Institute, University of Maryland, College Park, Maryland, USA
| | - Gongguan Liu
- Division of Immunology, Virginia-Maryland College of Veterinary Medicine and Maryland Pathogen Research Institute, University of Maryland, College Park, Maryland, USA
| | - Meiqing Shi
- Division of Immunology, Virginia-Maryland College of Veterinary Medicine and Maryland Pathogen Research Institute, University of Maryland, College Park, Maryland, USA
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Strickland AB, Shi M. Mechanisms of fungal dissemination. Cell Mol Life Sci 2021; 78:3219-3238. [PMID: 33449153 PMCID: PMC8044058 DOI: 10.1007/s00018-020-03736-z] [Citation(s) in RCA: 54] [Impact Index Per Article: 18.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2020] [Revised: 11/23/2020] [Accepted: 12/08/2020] [Indexed: 12/13/2022]
Abstract
Fungal infections are an increasing threat to global public health. There are more than six million fungal species worldwide, but less than 1% are known to infect humans. Most of these fungal infections are superficial, affecting the hair, skin and nails, but some species are capable of causing life-threatening diseases. The most common of these include Cryptococcus neoformans, Aspergillus fumigatus and Candida albicans. These fungi are typically innocuous and even constitute a part of the human microbiome, but if these pathogens disseminate throughout the body, they can cause fatal infections which account for more than one million deaths worldwide each year. Thus, systemic dissemination of fungi is a critical step in the development of these deadly infections. In this review, we discuss our current understanding of how fungi disseminate from the initial infection sites to the bloodstream, how immune cells eliminate fungi from circulation and how fungi leave the blood and enter distant organs, highlighting some recent advances and offering some perspectives on future directions.
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Affiliation(s)
- Ashley B Strickland
- Division of Immunology, Virginia-Maryland College of Veterinary Medicine and Maryland Pathogen Research Institute, University of Maryland, College Park, MD, USA.
| | - Meiqing Shi
- Division of Immunology, Virginia-Maryland College of Veterinary Medicine and Maryland Pathogen Research Institute, University of Maryland, College Park, MD, USA.
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14
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Alanio A. Dormancy in Cryptococcus neoformans: 60 years of accumulating evidence. J Clin Invest 2021; 130:3353-3360. [PMID: 32484459 DOI: 10.1172/jci136223] [Citation(s) in RCA: 25] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
Cryptococcus neoformans is an opportunistic yeast that is present worldwide and interacts with various organisms. In humans, it is responsible for cryptococcosis, a deadly invasive fungal infection that represents around 220,000 cases per year worldwide. Starting from the natural history of the disease in humans, there is accumulating evidence on the capacity of this organism to enter dormancy. In response to the harsh host environment, the yeast is able to adapt dramatically and escape the vigilance of the host's immune cells to survive. Indeed, the yeast exposed to the host takes on pleiotropic phenotypes, enabling the generation of populations in heterogeneous states, including dormancy, to eventually survive at low metabolic cost and revive in favorable conditions. The concept of dormancy has been validated in C. neoformans from both epidemiological and genotyping data, and more recently from the biological point of view with the characterization of dormancy through the description of viable but nonculturable cells.
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Affiliation(s)
- Alexandre Alanio
- Laboratoire de Parasitologie-Mycologie, Groupe Hospitalier Saint-Louis-Lariboisière-Fernand-Widal, Assistance Publique-Hôpitaux de Paris (AP-HP), Paris, France.,Molecular Mycology Unit, CNRS UMR 2000, National Reference Center for Invasive Mycoses and Antifungals (NRCMA), Institut Pasteur, Paris, France.,Université de Paris, Paris, France
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Lavrin T, Konte T, Kostanjšek R, Sitar S, Sepčič K, Prpar Mihevc S, Žagar E, Župunski V, Lenassi M, Rogelj B, Gunde Cimerman N. The Neurotropic Black Yeast Exophiala dermatitidis Induces Neurocytotoxicity in Neuroblastoma Cells and Progressive Cell Death. Cells 2020; 9:cells9040963. [PMID: 32295162 PMCID: PMC7226985 DOI: 10.3390/cells9040963] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2020] [Revised: 04/10/2020] [Accepted: 04/11/2020] [Indexed: 12/13/2022] Open
Abstract
The neurotropic and extremophilic black yeast Exophiala dermatitidis (Herpotrichellaceae) inhabits diverse indoor environments, in particular bathrooms, steam baths, and dishwashers. Here, we show that the selected strain, EXF-10123, is polymorphic, can grow at 37 °C, is able to assimilate aromatic hydrocarbons (toluene, mineral oil, n-hexadecane), and shows abundant growth with selected neurotransmitters (acetylcholine, gamma-aminobutyric acid, glycine, glutamate, and dopamine) as sole carbon sources. We have for the first time demonstrated the effect of E. dermatitidis on neuroblastoma cell model SH-SY5Y. Aqueous and organic extracts of E. dermatitidis biomass reduced SH-SY5Y viability by 51% and 37%, respectively. Melanized extracellular vesicles (EVs) prepared from this strain reduced viability of the SH-SY5Y to 21%, while non-melanized EVs were considerably less neurotoxic (79% viability). We also demonstrated direct interactions of E. dermatitidis with SH-SY5Y by scanning electron and confocal fluorescence microscopy. The observed invasion and penetration of neuroblastoma cells by E. dermatitidis hyphae presumably causes the degradation of most neuroblastoma cells in only three days. This may represent a so far unknown indirect or direct cause for the development of some neurodegenerative diseases such as Alzheimer’s.
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Affiliation(s)
- Teja Lavrin
- Biotechnical Faculty, University of Ljubljana, 1000 Ljubljana, Slovenia; (R.K.); (K.S.)
- Correspondence: (T.L.); (N.G.C.); Tel.: +386-(0)1-543-7652 (T.L.); +386-(0)1-320-3400 (N.G.C.)
| | - Tilen Konte
- Institute of Biochemistry, Faculty of Medicine, University of Ljubljana, 1000 Ljubljana, Slovenia; (T.K.); (M.L.)
| | - Rok Kostanjšek
- Biotechnical Faculty, University of Ljubljana, 1000 Ljubljana, Slovenia; (R.K.); (K.S.)
| | - Simona Sitar
- Laboratory for Polymer Chemistry and Technology, National Institute of Chemistry, 1000 Ljubljana, Slovenia; (S.S.); (E.Ž.)
| | - Kristina Sepčič
- Biotechnical Faculty, University of Ljubljana, 1000 Ljubljana, Slovenia; (R.K.); (K.S.)
| | | | - Ema Žagar
- Laboratory for Polymer Chemistry and Technology, National Institute of Chemistry, 1000 Ljubljana, Slovenia; (S.S.); (E.Ž.)
| | - Vera Župunski
- Faculty of Chemistry and Chemical Technology, University of Ljubljana, 1000 Ljubljana, Slovenia; (V.Ž.); (B.R.)
| | - Metka Lenassi
- Institute of Biochemistry, Faculty of Medicine, University of Ljubljana, 1000 Ljubljana, Slovenia; (T.K.); (M.L.)
| | - Boris Rogelj
- Faculty of Chemistry and Chemical Technology, University of Ljubljana, 1000 Ljubljana, Slovenia; (V.Ž.); (B.R.)
- Department of Biotechnology, Jožef Stefan Institute, 1000 Ljubljana, Slovenia
- Biomedical Research Institute, 1000 Ljubljana, Slovenia
| | - Nina Gunde Cimerman
- Biotechnical Faculty, University of Ljubljana, 1000 Ljubljana, Slovenia; (R.K.); (K.S.)
- Correspondence: (T.L.); (N.G.C.); Tel.: +386-(0)1-543-7652 (T.L.); +386-(0)1-320-3400 (N.G.C.)
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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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17
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Van Dyck K, Rogiers O, Vande Velde G, Van Dijck P. Let's shine a light on fungal infections: A noninvasive imaging toolbox. PLoS Pathog 2020; 16:e1008257. [PMID: 32134998 PMCID: PMC7058284 DOI: 10.1371/journal.ppat.1008257] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022] Open
Affiliation(s)
- Katrien Van Dyck
- Laboratory of molecular cell biology, Institute of botany and microbiology, Department of biology, KU Leuven, Leuven, Belgium
- VIB center for microbiology, Leuven, Belgium
| | - Ona Rogiers
- Laboratory of molecular cell biology, Institute of botany and microbiology, Department of biology, KU Leuven, Leuven, Belgium
- VIB center for microbiology, Leuven, Belgium
- Center for Inflammation Research, VIB, Technologiepark, Zwijnaarde, Belgium
- Department of Internal Medicine, Ghent University, Technologiepark, Zwijnaarde, Belgium
| | - Greetje Vande Velde
- Biomedical MRI/ MoSAIC, Dept. Imaging & Pathology, KU Leuven, Leuven, Belgium
| | - Patrick Van Dijck
- Laboratory of molecular cell biology, Institute of botany and microbiology, Department of biology, KU Leuven, Leuven, Belgium
- VIB center for microbiology, Leuven, Belgium
- * E-mail:
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18
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Nonlytic exocytosis of Cryptococcus neoformans from neutrophils in the brain vasculature. Cell Commun Signal 2019; 17:117. [PMID: 31500648 PMCID: PMC6734394 DOI: 10.1186/s12964-019-0429-0] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2019] [Accepted: 08/29/2019] [Indexed: 12/31/2022] Open
Abstract
Background Cryptococcus neoformans (C. neoformans) is an encapsulated budding yeast that causes life-threatening meningoencephalitis in immunocompromised individuals, especially those with acquired immunodeficiency syndrome (AIDS). To cause meningoencephalitis, C. neoformans circulating in the bloodstream must first be arrested in the brain microvasculature. Neutrophils, the most abundant phagocytes in the bloodstream and the first leukocytes to be recruited to an infection site, can ingest C. neoformans. Little is known about how neutrophils interact with arrested fungal cells in the brain microvasculature. Methods A blood-brain barrier (BBB) in vitro model was established. The interactions between neutrophils adhering to brain endothelial cells and fungi were observed under a live cell imaging microscope. A flow cytometry assay was developed to explore the mechanisms. Immunofluorescence staining of brain tissues was utilized to validate the in vitro phenomena. Results Using real-time imaging, we observed that neutrophils adhered to a monolayer of mouse brain endothelial cells could expel ingested C. neoformans without lysis of the neutrophils or fungi in vitro, demonstrating nonlytic exocytosis of fungal cells from neutrophils. Furthermore, nonlytic exocytosis of C. neoformans from neutrophils was influenced by either the fungus (capsule and viability) or the neutrophil (phagosomal pH and actin polymerization). Moreover, nonlytic exocytosis of C. neoformans from neutrophils was recorded in brain tissue. Conclusion These results highlight a novel function by which neutrophils extrude C. neoformans in the brain vasculature. Graphical abstract ![]()
Electronic supplementary material The online version of this article (10.1186/s12964-019-0429-0) contains supplementary material, which is available to authorized users.
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Coelho C, Camacho E, Salas A, Alanio A, Casadevall A. Intranasal Inoculation of Cryptococcus neoformans in Mice Produces Nasal Infection with Rapid Brain Dissemination. mSphere 2019; 4:e00483-19. [PMID: 31391283 PMCID: PMC6686232 DOI: 10.1128/msphere.00483-19] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2019] [Accepted: 07/22/2019] [Indexed: 12/12/2022] Open
Abstract
Cryptococcus neoformans is an important fungal pathogen, causing life-threatening pneumonia and meningoencephalitis. Brain dissemination of C. neoformans is thought to be a consequence of an active infection in the lung which then extravasates to other sites. Brain invasion results from dissemination via either transport by free yeast cells in the bloodstream or Trojan horse transport within mononuclear phagocytes. We assessed brain dissemination in three mouse models of infection: intravenous, intratracheal, and intranasal models. All three modes of infection resulted in dissemination of C. neoformans to the brain in less than 3 h. Further, C. neoformans was detected in the entirety of the upper respiratory tract and the ear canals of mice. In recent years, intranasal infection has become a popular mechanism to induce pulmonary infection because it avoids surgery, but our findings show that instillation of C. neoformans produces cryptococcal nasal infection. These findings imply that immunological studies using intranasal infection should assume that the initial sites of infection of infection are brain, lung, and upper respiratory tract, including the nasal airways.IMPORTANCECryptococcus neoformans causes an estimated 181, 000 deaths each year, mostly associated with untreated HIV/AIDS. C. neoformans has a ubiquitous worldwide distribution. Humans become infected from exposure to environmental sources, after which the fungus lays dormant within the human body. Upon AIDS-induced immunosuppression or therapy-induced immunosuppression (required for organ transplant recipients or those suffering from autoimmune disorders), cryptococcal disease reactivates and causes life-threatening meningitis and pneumonia. This study showed that upon contact with the host, C. neoformans can quickly (a few hours) reach the host brain and also colonizes the nose of infected animals. Therefore, this work paves the way to better knowledge of how C. neoformans travels through the host body. Understanding how C. neoformans infects, disseminates, and survives within the host is critically required so that we can prevent infections and the disease caused by this deadly fungus.
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Affiliation(s)
- Carolina Coelho
- W. Harry Feinstone Department of Molecular Microbiology and Immunology, Johns Hopkins University Bloomberg School of Public Health, Baltimore, Maryland, USA
- Medical Research Council Centre for Medical Mycology, Institute of Medical Sciences, University of Aberdeen, Aberdeen, United Kingdom
- Department of Biosciences, College of Life and Environmental Sciences, University of Exeter, Exeter, United Kingdom
| | - Emma Camacho
- W. Harry Feinstone Department of Molecular Microbiology and Immunology, Johns Hopkins University Bloomberg School of Public Health, Baltimore, Maryland, USA
| | - Antonio Salas
- Johns Hopkins School of Medicine, Baltimore, Maryland, USA
| | - Alexandre Alanio
- Institut Pasteur, Molecular Mycology Unit, CNRS UMR2000, Université Paris Diderot, Sorbonne Paris Cité, 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
| | - Arturo Casadevall
- W. Harry Feinstone Department of Molecular Microbiology and Immunology, Johns Hopkins University Bloomberg School of Public Health, Baltimore, Maryland, USA
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Chapuis AF, Ballou ER, MacCallum DM. A Bright Future for Fluorescence Imaging of Fungi in Living Hosts. J Fungi (Basel) 2019; 5:jof5020029. [PMID: 30987114 PMCID: PMC6616859 DOI: 10.3390/jof5020029] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2019] [Revised: 03/27/2019] [Accepted: 03/29/2019] [Indexed: 12/24/2022] Open
Abstract
Traditional in vivo investigation of fungal infection and new antifungal therapies in mouse models is usually carried out using post mortem methodologies. However, biomedical imaging techniques focusing on non-invasive techniques using bioluminescent and fluorescent proteins have become valuable tools. These new techniques address ethical concerns as they allow reduction in the number of animals required to evaluate new antifungal therapies. They also allow better understanding of the growth and spread of the pathogen during infection. In this review, we concentrate on imaging technologies using different fungal reporter proteins. We discuss the advantages and limitations of these different reporters and compare the efficacy of bioluminescent and fluorescent proteins for fungal research.
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Affiliation(s)
- Ambre F Chapuis
- MRC Centre for Medical Mycology at the University of Aberdeen, Institute of Medical Sciences, University of Aberdeen, Foresterhill, Aberdeen AB25 2ZD, UK.
| | - Elizabeth R Ballou
- Institute of Microbiology and Infection, School of Biosciences, University of Birmingham, Birmingham B15 2TT, UK.
| | - Donna M MacCallum
- MRC Centre for Medical Mycology at the University of Aberdeen, Institute of Medical Sciences, University of Aberdeen, Foresterhill, Aberdeen AB25 2ZD, UK.
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Shi M, Mody CH. Fungal Infection in the Brain: What We Learned from Intravital Imaging. Front Immunol 2016; 7:292. [PMID: 27532000 PMCID: PMC4969284 DOI: 10.3389/fimmu.2016.00292] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2016] [Accepted: 07/19/2016] [Indexed: 11/13/2022] Open
Abstract
Approximately 1.2 billion people suffer from fungal diseases worldwide. Arguably, the most serious manifestation occurs when pathogenic fungi infect the brain, often causing fatal meningoencephalitis. For most fungi, infection occurs via the vascular route. The organism must first be arrested in the brain microvasculature and transmigrate into the brain parenchyma across the blood–brain barrier. As a result, host immune cells are recruited into the brain to contain the fungi. However, it remains poorly understood how fungi traffic to, and migrate into the brain and how immune cells interact with invading fungi in the brain. A new era of intravital fluorescence microscopy has begun to provide insights. We are able to employ this powerful approach to study dynamic interactions of disseminating fungi with brain endothelial cells as well as resident and recruited immune cells during the brain infection. In this review, with a focus on Cryptococcus neoformans, we will provide an overview of the application of intravital imaging in fungal infections in the brain, discuss recent findings and speculate on possible future research directions.
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Affiliation(s)
- Meiqing Shi
- Division of Immunology, Virginia-Maryland Regional College of Veterinary Medicine, University of Maryland , College Park, MD , USA
| | - Christopher H Mody
- Department of Microbiology, Immunology and Infectious Diseases, University of Calgary, Calgary, AB, Canada; Department of Internal Medicine, University of Calgary, Calgary, AB, Canada
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22
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Sun D, Zhang M, Liu G, Wu H, Li C, Zhou H, Zhang X, Shi M. Intravascular clearance of disseminating Cryptococcus neoformans in the brain can be improved by enhancing neutrophil recruitment in mice. Eur J Immunol 2016; 46:1704-14. [PMID: 27109176 DOI: 10.1002/eji.201546239] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2015] [Revised: 03/06/2016] [Accepted: 04/18/2016] [Indexed: 12/23/2022]
Abstract
Extrapulmonary dissemination of Cryptococcus neoformans (C. neoformans) is one of the most critical steps in the development of meningoencephalitis. Here, we report that clearance of the disseminating C. neoformans occurs within the brain microvasculature. Interestingly, the efficiency of the intravascular clearance in the brain is reduced compared to that in the lung. Intravascular clearance is mainly mediated by neutrophils, and complement C5a receptor signaling is crucial for mediating neutrophil recruitment in the vasculature. C. neoformans stimulated actin polymerization of neutrophils is critically involved in their recruitment to the lung, which is associated with the unique vascular structure detected in the lung. The relatively lower efficiency of fungal clearance in the brain vasculature correlates with less efficient recruitment of neutrophils. Accordingly, intravascular clearance of C. neoformans in the brain could be remarkably improved by increasing the recruitment of neutrophils. We conclude that neutrophils have the ability to eliminate C. neoformans arrested in the vasculature. However, insufficient recruitment of neutrophils limited the optimal clearance of this microorganism in the brain. These results imply that a therapeutic strategy aimed at enhancing the accumulation of neutrophils could help prevent cryptococcal meningoencephalitis.
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Affiliation(s)
- Donglei Sun
- Division of Immunology, Virginia-Maryland Regional College of Veterinary Medicine, University of Maryland, College Park, MD, USA
| | - 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, China
| | - Gongguan Liu
- Division of Immunology, Virginia-Maryland Regional College of Veterinary Medicine, University of Maryland, College Park, MD, USA
| | - Hui Wu
- Division of Immunology, Virginia-Maryland Regional College of Veterinary Medicine, University of Maryland, College Park, MD, USA
| | - Chang Li
- Division of Immunology, Virginia-Maryland Regional College of Veterinary Medicine, University of Maryland, College Park, MD, USA
| | - Hong Zhou
- Department of Immunology, Nanjing Medical University, Nanjing, China
| | - Xiquan Zhang
- Department of Animal Genetics, Breeding and Reproduction, South China Agricultural University, Guangzhou, China
| | - Meiqing Shi
- Division of Immunology, Virginia-Maryland Regional College of Veterinary Medicine, University of Maryland, College Park, MD, USA
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23
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Zhang M, Sun D, Liu G, Wu H, Zhou H, Shi M. Real-time in vivo imaging reveals the ability of neutrophils to remove Cryptococcus neoformans directly from the brain vasculature. J Leukoc Biol 2015; 99:467-73. [PMID: 26428677 DOI: 10.1189/jlb.4ab0715-281r] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2015] [Accepted: 09/21/2015] [Indexed: 11/24/2022] Open
Abstract
Although neutrophils are typically the first immune cells attracted to an infection site, little is known about how neutrophils dynamically interact with invading pathogens in vivo. Here, with the use of intravital microscopy, we demonstrate that neutrophils migrate to the arrested Cryptococcus neoformans, a leading agent to cause meningoencephalitis, in the brain microvasculature. Following interactions with C. neoformans, neutrophils were seen to internalize the organism and then circulate back into the bloodstream, resulting in a direct removal of the organism from the endothelial surface before its transmigration into the brain parenchyma. C. neoformans infection led to enhanced expression of adhesion molecules macrophage 1 antigen on neutrophils and ICAM-1 on brain endothelial cells. Depletion of neutrophils enhanced the brain fungal burden. Complement C3 was critically involved in the recognition of C. neoformans by neutrophils and subsequent clearance of the organism from the brain. Together, our finding of the direct removal of C. neoformans by neutrophils from its arrested site may represent a novel mechanism of host defense in the brain, in addition to the known, direct killing of microorganisms at the infection sites. These data are the first to characterize directly the dynamic interactions of leukocytes with a microbe in the brain of a living animal.
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Affiliation(s)
- Mingshun Zhang
- *Division of Immunology, Virginia-Maryland Regional College of Veterinary Medicine, University of Maryland, College Park, Maryland, USA; and 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, Maryland, USA; and Department of Immunology, Nanjing Medical University, Nanjing, Jiangsu, China
| | - Gongguan Liu
- *Division of Immunology, Virginia-Maryland Regional College of Veterinary Medicine, University of Maryland, College Park, Maryland, USA; and Department of Immunology, Nanjing Medical University, Nanjing, Jiangsu, China
| | - Hui Wu
- *Division of Immunology, Virginia-Maryland Regional College of Veterinary Medicine, University of Maryland, College Park, Maryland, USA; and Department of Immunology, Nanjing Medical University, Nanjing, Jiangsu, China
| | - Hong Zhou
- *Division of Immunology, Virginia-Maryland Regional College of Veterinary Medicine, University of Maryland, College Park, Maryland, USA; and Department of Immunology, Nanjing Medical University, Nanjing, Jiangsu, China
| | - Meiqing Shi
- *Division of Immunology, Virginia-Maryland Regional College of Veterinary Medicine, University of Maryland, College Park, Maryland, USA; and Department of Immunology, Nanjing Medical University, Nanjing, Jiangsu, China
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Shao K, Zhang Y, Ding N, Huang S, Wu J, Li J, Yang C, Leng Q, Ye L, Lou J, Zhu L, Jiang C. Functionalized nanoscale micelles with brain targeting ability and intercellular microenvironment biosensitivity for anti-intracranial infection applications. Adv Healthc Mater 2015; 4:291-300. [PMID: 25124929 DOI: 10.1002/adhm.201400214] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2014] [Revised: 06/16/2014] [Indexed: 01/28/2023]
Abstract
Due to complication factors such as blood-brain barrier (BBB), integrating high efficiency of brain target ability with specific cargo releasing into one nanocarrier seems more important. A brain targeting nanoscale system is developed using dehydroascorbic acid (DHA) as targeting moiety. DHA has high affinity with GLUT1 on BBB. More importantly, the GLUT1 transportation of DHA represents a "one-way" accumulative priority from blood into brain. The artificial micelles are fabricated by a disulfide linkage, forming a bio-responsive inner barrier, which can maintain micelles highly stable in circulation and shield the leakage of entrapped drug before reaching the targeting cells. The designed micelles can cross BBB and be further internalized by brain cells. Once within the cells, the drug release can be triggered by high intracellular level of glutathione (GSH). Itraconazole (ITZ) is selected as the model drug because of its poor brain permeability and low stability in blood. It demonstrates that the functionalized nanoscale micelles can achieve highly effective direct drug delivery to targeting site. Based on the markedly increased stability in blood circulation and improved brain delivery efficiency of ITZ, DHA-modified micelles show highly effective in anti-intracranial infection. Therefore, this smart nanodevice shows a promising application for the treatment of brain diseases.
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Affiliation(s)
- Kun Shao
- Department of Pharmaceutics; School of Pharmacy; Fudan University; 826 Zhangheng Road Shanghai 201203 China
| | - Yu Zhang
- Department of Pharmaceutics; School of Pharmacy; Fudan University; 826 Zhangheng Road Shanghai 201203 China
| | - Ning Ding
- Department of Medical Chemistry; School of Pharmacy; Fudan University; 826 Zhangheng Road Shanghai 201203 China
| | - Shixian Huang
- Department of Pharmaceutics; School of Pharmacy; Fudan University; 826 Zhangheng Road Shanghai 201203 China
| | - Jiqin Wu
- Department of Infectious Diseases; Huashan Hospital; Fudan University; 12 Urumqi Middle Road Shanghai 200040 China
| | - Jianfeng Li
- Department of Pharmaceutics; School of Pharmacy; Fudan University; 826 Zhangheng Road Shanghai 201203 China
| | - Chunfu Yang
- Key Laboratory of Molecular Virology and Immunology; Institut Pasteur of Shanghai; Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences; 411 Hefei Road Shanghai 200031 China
| | - Qibin Leng
- Key Laboratory of Molecular Virology and Immunology; Institut Pasteur of Shanghai; Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences; 411 Hefei Road Shanghai 200031 China
| | - Liya Ye
- Institute of Clinical Medical Sciences; China-Japan Friendship Hospital; The ministry of Health; 2 East Yinghua Road Beijing 100029 China
| | - Jinning Lou
- Institute of Clinical Medical Sciences; China-Japan Friendship Hospital; The ministry of Health; 2 East Yinghua Road Beijing 100029 China
| | - Liping Zhu
- Department of Infectious Diseases; Huashan Hospital; Fudan University; 12 Urumqi Middle Road Shanghai 200040 China
| | - Chen Jiang
- Department of Pharmaceutics; School of Pharmacy; Fudan University; 826 Zhangheng Road Shanghai 201203 China
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Santi L, Beys-da-Silva WO, Berger M, Calzolari D, Guimarães JA, Moresco JJ, Yates JR. Proteomic profile of Cryptococcus neoformans biofilm reveals changes in metabolic processes. J Proteome Res 2014; 13:1545-59. [PMID: 24467693 PMCID: PMC3993910 DOI: 10.1021/pr401075f] [Citation(s) in RCA: 47] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
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Cryptococcus neoformans, a pathogenic yeast, causes
meningoencephalitis, especially in immunocompromised patients, leading
in some cases to death. Microbes in biofilms can cause persistent
infections, which are harder to treat. Cryptococcal biofilms are becoming
common due to the growing use of brain valves and other medical devices.
Using shotgun proteomics we determine the differences in protein abundance
between biofilm and planktonic cells. Applying bioinformatic tools,
we also evaluated the metabolic pathways involved in biofilm maintenance
and protein interactions. Our proteomic data suggest general changes
in metabolism, protein turnover, and global stress responses. Biofilm
cells show an increase in proteins related to oxidation–reduction,
proteolysis, and response to stress and a reduction in proteins related
to metabolic process, transport, and translation. An increase in pyruvate-utilizing
enzymes was detected, suggesting a shift from the TCA cycle to fermentation-derived
energy acquisition. Additionally, we assign putative roles to 33 proteins
previously categorized as hypothetical. Many changes in metabolic
enzymes were identified in studies of bacterial biofilm, potentially
revealing a conserved strategy in biofilm lifestyle.
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Affiliation(s)
- Lucélia Santi
- Department of Chemical Physiology, The Scripps Research Institute , North Torrey Pines Road, Suite 11, La Jolla, California 92037, United States
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Shi M, Calaruso P, Mody CH. Corrigendum: Real-time in vivoimaging of fungal migration to the central nervous system. Cell Microbiol 2013. [DOI: 10.1111/cmi.12120] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Meiqing Shi
- Virginia-Maryland Regional College of Veterinary Medicine; University of Maryland; College Park MD USA
| | - Pina Calaruso
- Department of Physiology and Pharmacology; University of Calgary; Calgary Alberta Canada
| | - Christopher H. Mody
- Department of Internal Medicine; University of Calgary; Calgary Alberta Canada
- Department of Microbiology, Immunology and Infectious Disease; University of Calgary; Calgary Alberta Canada
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Bouklas T, Fries BC. Cryptococcus neoformans constitutes an ideal model organism to unravel the contribution of cellular aging to the virulence of chronic infections. Curr Opin Microbiol 2013; 16:391-7. [PMID: 23631868 DOI: 10.1016/j.mib.2013.03.011] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2013] [Revised: 03/21/2013] [Accepted: 03/28/2013] [Indexed: 10/26/2022]
Abstract
Aging affects all organisms, from unicellular yeasts to multicellular humans. Studies in model organisms demonstrate that the pathways that mediate the two forms of aging, replicative and chronological, are highly conserved. Most studies are focused on the effect of aging on an individual cell rather than a whole population. Complex longevity regulation, however, makes aging a highly adaptive trait that is subject to natural selection. Recent studies have shed light on the potential relevance of aging in fungal pathogens, which undergo replicative aging when they expand in the host environment. Hence, pathogens causing chronic infections can constitute ideal model organisms in unraveling the contribution of selection to aging within a population and help elucidate the contribution of aging itself to the virulence of infections.
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Affiliation(s)
- Tejas Bouklas
- Department of Microbiology and Immunology, Albert Einstein College of Medicine of Yeshiva University, 1300 Morris Park Avenue, Bronx, NY 10461, USA
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