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Hughes ES, Tuck LR, He Z, Ballou ER, Wallace EWJ. A trade-off between proliferation and defense in the fungal pathogen Cryptococcus at alkaline pH is controlled by the transcription factor GAT201. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2023.06.14.543486. [PMID: 37398450 PMCID: PMC10312749 DOI: 10.1101/2023.06.14.543486] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 07/04/2023]
Abstract
Cryptococcus is a fungal pathogen whose virulence relies on proliferation in and dissemination to host sites, and on synthesis of a defensive yet metabolically costly polysaccharide capsule. Regulatory pathways required for Cryptococcus virulence include a GATA-like transcription factor, Gat201, that regulates Cryptococcal virulence in both capsule-dependent and capsule-independent ways. Here we show that Gat201 is part of a negative regulatory pathway that limits fungal survival at alkaline pH. RNA-seq analysis found strong induction of GAT201 expression within minutes of transfer to RPMI media at alkaline pH. Microscopy, growth curves, and colony forming unit assays show that in RPMI at alkaline pH wild-type Cryptococcus neoformans yeast cells produce capsule but do not bud or maintain viability, while gat201Δ cells make buds and maintain viability, yet fail to produce capsule. GAT201 is required for transcriptional upregulation of a specific set of genes, the majority of which are direct Gat201 targets. Evolutionary analysis shows that Gat201 is in a subfamily of GATA-like transcription factors that is conserved within pathogenic fungi but absent in model yeasts. This work identifies the Gat201 pathway as controlling a trade-off between proliferation and production of defensive capsule. The assays established here will allow characterisation of the mechanisms of action of the Gat201 pathway. Together, our findings urge improved understanding of the regulation of proliferation as a driver of fungal pathogenesis. Author Summary Micro-organisms face trade-offs in adapting to their environments. For example, pathogens adapting to host niches must balance investing in proliferation - reproduction and growth - against investing in defense against the host immune system. Cryptococcus neoformans is an encapsulated fungal pathogen that can infect human airways and, in immunocompromised people, can move to the brain to cause life-threatening meningitis. It is well appreciated that fungal persistence in these sites depends on production of a sugar capsule that surrounds the cell, hiding it from host detection. However, in both the lung and brain, fungal proliferation through budding is also a major driver of pathogenesis: both cryptococcal pneumonia and meningitis are characterised by high yeast burden. This presents a trade-off between production of a metabolically costly capsule and cellular proliferation. The regulators of Cryptococcus proliferation are poorly understood, as they are distinct from other model yeasts at the level of cell cycle and morphogenesis. In this work, we study this trade off growing Cryptococcus under conditions that approximate the alkaline surface of human airways, and that restrict fungal growth. We identify a GATA-like transcription factor, Gat201, and its target, Gat204, that positively regulate capsule production and negatively regulate proliferation. The GAT201 pathway is conserved within pathogenic fungi but lost in other model yeasts. Together our findings reveal how a fungal pathogen regulates the balance between defense and proliferation and highlight the need for improved understanding of proliferation in non-model systems.
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Goughenour K, Creech A, Xu J, He X, Hissong R, Giamberardino C, Tenor J, Toffaletti D, Perfect J, Olszewski M. Cryptococcus neoformans trehalose-6-phosphate synthase (tps1) promotes organ-specific virulence and fungal protection against multiple lines of host defenses. Front Cell Infect Microbiol 2024; 14:1392015. [PMID: 38841113 PMCID: PMC11150607 DOI: 10.3389/fcimb.2024.1392015] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2024] [Accepted: 04/04/2024] [Indexed: 06/07/2024] Open
Abstract
Trehalose-6-phosphate synthase (TPS1) was identified as a virulence factor for Cryptococcus neoformans and a promising therapeutic target. This study reveals previously unknown roles of TPS1 in evasion of host defenses during pulmonary and disseminated phases of infection. In the pulmonary infection model, TPS1-deleted (tps1Δ) Cryptococci are rapidly cleared by mouse lungs whereas TPS1-sufficent WT (H99) and revertant (tps1Δ:TPS1) strains expand in the lungs and disseminate, causing 100% mortality. Rapid pulmonary clearance of tps1Δ mutant is T-cell independent and relies on its susceptibility to lung resident factors and innate immune factors, exemplified by tps1Δ but not H99 inhibition in a coculture with dispersed lung cells and its rapid clearance coinciding with innate leukocyte infiltration. In the disseminated model of infection, which bypasses initial lung-fungus interactions, tps1Δ strain remains highly attenuated. Specifically, tps1Δ mutant is unable to colonize the lungs from the bloodstream or expand in spleens but is capable of crossing into the brain, where it remains controlled even in the absence of T cells. In contrast, strains H99 and tps1Δ:TPS1 rapidly expand in all studied organs, leading to rapid death of the infected mice. Since the rapid pulmonary clearance of tps1Δ mutant resembles a response to acapsular strains, the effect of tps1 deletion on capsule formation in vitro and in vivo was examined. Tps1Δ cryptococci form capsules but with a substantially reduced size. In conclusion, TPS1 is an important virulence factor, allowing C. neoformans evasion of resident pulmonary and innate defense mechanisms, most likely via its role in cryptococcal capsule formation.
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Affiliation(s)
- Kristie Goughenour
- Research Service, Lieutenant Colonel Charles S. Kettles VA Medical Center, Ann Arbor, MI, United States
- Division of Pulmonary and Critical Care Medicine, Department of Internal Medicine, University of Michigan, Ann Arbor, MI, United States
| | - Arianna Creech
- Research Service, Lieutenant Colonel Charles S. Kettles VA Medical Center, Ann Arbor, MI, United States
- Division of Pulmonary and Critical Care Medicine, Department of Internal Medicine, University of Michigan, Ann Arbor, MI, United States
| | - Jintao Xu
- Research Service, Lieutenant Colonel Charles S. Kettles VA Medical Center, Ann Arbor, MI, United States
- Division of Pulmonary and Critical Care Medicine, Department of Internal Medicine, University of Michigan, Ann Arbor, MI, United States
| | - Xiumiao He
- Research Service, Lieutenant Colonel Charles S. Kettles VA Medical Center, Ann Arbor, MI, United States
| | - Rylan Hissong
- Research Service, Lieutenant Colonel Charles S. Kettles VA Medical Center, Ann Arbor, MI, United States
- Division of Pulmonary and Critical Care Medicine, Department of Internal Medicine, University of Michigan, Ann Arbor, MI, United States
| | - Charles Giamberardino
- Division of Infectious Diseases, Department of Medicine, Duke University, Durham, NC, United States
| | - Jennifer Tenor
- Division of Infectious Diseases, Department of Medicine, Duke University, Durham, NC, United States
| | - Dena Toffaletti
- Division of Infectious Diseases, Department of Medicine, Duke University, Durham, NC, United States
| | - John Perfect
- Division of Infectious Diseases, Department of Medicine, Duke University, Durham, NC, United States
| | - Michal Olszewski
- Research Service, Lieutenant Colonel Charles S. Kettles VA Medical Center, Ann Arbor, MI, United States
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Zhu F, Zhou Z, Ma S, Xu Y, Tan C, Yang H, Zhang P, Qin R, Luo Y, Pan P, Chen J. Design of a cryptococcus neoformans vaccine by subtractive proteomics combined with immunoinformatics. Int Immunopharmacol 2024; 135:112242. [PMID: 38772296 DOI: 10.1016/j.intimp.2024.112242] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2024] [Revised: 04/22/2024] [Accepted: 05/08/2024] [Indexed: 05/23/2024]
Abstract
The emergence of Cryptococcus neoformans has posed an undeniable burden to many regions worldwide, with its strains mainly entering the lungs through the respiratory tract and spreading throughout the body. Limitations of drug regimens, such as high costs and limited options, have directed our attention toward the promising field of vaccine development. In this study, the subtractive proteomics approach was employed to select target proteins from databases that can accurately cover serotypes A and D of the Cryptococcus neoformans. Further, two multi-epitope vaccines consisting of T and B cell epitopes were demonstrated that they have good structural stability and could bind with immune receptor to induce desired immune responses in silico. After further evaluation, these vaccines show the potential for large-scale production and applicability to the majority of the population of the world. In summary, these two vaccines have been theoretically proven to combat Cryptococcus neoformans infections, awaiting further experimental validation of their actual protective effects.
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Affiliation(s)
- Fei Zhu
- Department of Respiratory Medicine, National Key Clinical Specialty, Branch of National Clinical Research Center for Respiratory Disease, Xiangya Hospital, Central South University, Changsha, Hunan, China; Center of Respiratory Medicine, Xiangya Hospital, Central South University, Changsha, Hunan, China; Clinical Research Center for Respiratory Diseases in Hunan Province, Changsha, Hunan, China; Hunan Engineering Research Center for Intelligent Diagnosis and Treatment of Respiratory Disease, Changsha, Hunan, China; National Clinical Research Center for Geriatric Disorders, Xiangya Hospital, Changsha, Hunan, China; FuRong Laboratory, Changsha 410078, Hunan, China
| | - Ziyou Zhou
- Department of Respiratory Medicine, National Key Clinical Specialty, Branch of National Clinical Research Center for Respiratory Disease, Xiangya Hospital, Central South University, Changsha, Hunan, China; Center of Respiratory Medicine, Xiangya Hospital, Central South University, Changsha, Hunan, China; Clinical Research Center for Respiratory Diseases in Hunan Province, Changsha, Hunan, China; Hunan Engineering Research Center for Intelligent Diagnosis and Treatment of Respiratory Disease, Changsha, Hunan, China; National Clinical Research Center for Geriatric Disorders, Xiangya Hospital, Changsha, Hunan, China; FuRong Laboratory, Changsha 410078, Hunan, China
| | - Shiyang Ma
- Department of Respiratory Medicine, National Key Clinical Specialty, Branch of National Clinical Research Center for Respiratory Disease, Xiangya Hospital, Central South University, Changsha, Hunan, China; Center of Respiratory Medicine, Xiangya Hospital, Central South University, Changsha, Hunan, China; Clinical Research Center for Respiratory Diseases in Hunan Province, Changsha, Hunan, China; Hunan Engineering Research Center for Intelligent Diagnosis and Treatment of Respiratory Disease, Changsha, Hunan, China; National Clinical Research Center for Geriatric Disorders, Xiangya Hospital, Changsha, Hunan, China; FuRong Laboratory, Changsha 410078, Hunan, China
| | - Yizhong Xu
- Department of Respiratory Medicine, National Key Clinical Specialty, Branch of National Clinical Research Center for Respiratory Disease, Xiangya Hospital, Central South University, Changsha, Hunan, China; Center of Respiratory Medicine, Xiangya Hospital, Central South University, Changsha, Hunan, China; Clinical Research Center for Respiratory Diseases in Hunan Province, Changsha, Hunan, China; Hunan Engineering Research Center for Intelligent Diagnosis and Treatment of Respiratory Disease, Changsha, Hunan, China; National Clinical Research Center for Geriatric Disorders, Xiangya Hospital, Changsha, Hunan, China; FuRong Laboratory, Changsha 410078, Hunan, China
| | - Caixia Tan
- National Clinical Research Center for Geriatric Disorders, Xiangya Hospital, Changsha, Hunan, China; Department of Infection Control Center of Xiangya Hospital, Central South University, Changsha, Hunan, China
| | - Hang Yang
- Department of Respiratory Medicine, National Key Clinical Specialty, Branch of National Clinical Research Center for Respiratory Disease, Xiangya Hospital, Central South University, Changsha, Hunan, China; Center of Respiratory Medicine, Xiangya Hospital, Central South University, Changsha, Hunan, China; Clinical Research Center for Respiratory Diseases in Hunan Province, Changsha, Hunan, China; Hunan Engineering Research Center for Intelligent Diagnosis and Treatment of Respiratory Disease, Changsha, Hunan, China; National Clinical Research Center for Geriatric Disorders, Xiangya Hospital, Changsha, Hunan, China; FuRong Laboratory, Changsha 410078, Hunan, China
| | - Peipei Zhang
- Department of Respiratory Medicine, National Key Clinical Specialty, Branch of National Clinical Research Center for Respiratory Disease, Xiangya Hospital, Central South University, Changsha, Hunan, China; Center of Respiratory Medicine, Xiangya Hospital, Central South University, Changsha, Hunan, China; Clinical Research Center for Respiratory Diseases in Hunan Province, Changsha, Hunan, China; Hunan Engineering Research Center for Intelligent Diagnosis and Treatment of Respiratory Disease, Changsha, Hunan, China; National Clinical Research Center for Geriatric Disorders, Xiangya Hospital, Changsha, Hunan, China; FuRong Laboratory, Changsha 410078, Hunan, China
| | - Rongliu Qin
- Department of Respiratory Medicine, National Key Clinical Specialty, Branch of National Clinical Research Center for Respiratory Disease, Xiangya Hospital, Central South University, Changsha, Hunan, China; Center of Respiratory Medicine, Xiangya Hospital, Central South University, Changsha, Hunan, China; Clinical Research Center for Respiratory Diseases in Hunan Province, Changsha, Hunan, China; Hunan Engineering Research Center for Intelligent Diagnosis and Treatment of Respiratory Disease, Changsha, Hunan, China; National Clinical Research Center for Geriatric Disorders, Xiangya Hospital, Changsha, Hunan, China; FuRong Laboratory, Changsha 410078, Hunan, China
| | - Yuying Luo
- Department of Respiratory Medicine, National Key Clinical Specialty, Branch of National Clinical Research Center for Respiratory Disease, Xiangya Hospital, Central South University, Changsha, Hunan, China; Center of Respiratory Medicine, Xiangya Hospital, Central South University, Changsha, Hunan, China; Clinical Research Center for Respiratory Diseases in Hunan Province, Changsha, Hunan, China; Hunan Engineering Research Center for Intelligent Diagnosis and Treatment of Respiratory Disease, Changsha, Hunan, China; National Clinical Research Center for Geriatric Disorders, Xiangya Hospital, Changsha, Hunan, China; FuRong Laboratory, Changsha 410078, Hunan, China
| | - Pinhua Pan
- Department of Respiratory Medicine, National Key Clinical Specialty, Branch of National Clinical Research Center for Respiratory Disease, Xiangya Hospital, Central South University, Changsha, Hunan, China; Center of Respiratory Medicine, Xiangya Hospital, Central South University, Changsha, Hunan, China; Clinical Research Center for Respiratory Diseases in Hunan Province, Changsha, Hunan, China; Hunan Engineering Research Center for Intelligent Diagnosis and Treatment of Respiratory Disease, Changsha, Hunan, China; National Clinical Research Center for Geriatric Disorders, Xiangya Hospital, Changsha, Hunan, China; FuRong Laboratory, Changsha 410078, Hunan, China.
| | - Jie Chen
- Department of Respiratory Medicine, National Key Clinical Specialty, Branch of National Clinical Research Center for Respiratory Disease, Xiangya Hospital, Central South University, Changsha, Hunan, China; Center of Respiratory Medicine, Xiangya Hospital, Central South University, Changsha, Hunan, China; Clinical Research Center for Respiratory Diseases in Hunan Province, Changsha, Hunan, China; Hunan Engineering Research Center for Intelligent Diagnosis and Treatment of Respiratory Disease, Changsha, Hunan, China; National Clinical Research Center for Geriatric Disorders, Xiangya Hospital, Changsha, Hunan, China; FuRong Laboratory, Changsha 410078, Hunan, China.
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Miranda BA, Freitas GJC, Leocádio VAT, Costa MC, Emídio ECP, Ribeiro NQ, Carmo PHF, Gouveia-Eufrásio L, Hubner J, Tavares LP, Arifa RDN, Brito CB, Silva MF, Teixeira MM, Paixão TA, Peres NTA, Fagundes CT, Santos DA. Secondary Streptococcus pneumoniae infection increases morbidity and mortality during murine cryptococcosis. Immunology 2024; 171:92-103. [PMID: 37814467 DOI: 10.1111/imm.13701] [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: 04/13/2023] [Accepted: 09/21/2023] [Indexed: 10/11/2023] Open
Abstract
Microorganisms that cause pneumonia and translocate to the central nervous system (CNS) are responsible for high mortality worldwide. The fungus Cryptococcus gattii (Cg) and the bacteria Streptococcus pneumoniae (Sp) target the same infection organs. This study aimed to investigate the consequences of secondary Sp infection during murine cryptococcosis. Mice infected with Sp after Cg showed significantly increased lethality and a drop in scores of motor behaviour, neuropsychiatric status and autonomous function. Previous Cg infection favoured Sp multiplication in the lungs, causing intense inflammation and necrosis, with further increased bacterial translocation to the spleen, liver and brain. This phenotype was associated with increased platelet-activating factor receptor (Pafr) gene expression, reduced M1 macrophage recruitment, and high levels of proinflammatory mediators. Strategies to overcome early mortality (i.e., infection of Pafr-/- mice, treatment with IL-1 inhibitor or corticoid) were insufficient to revert this phenotype. These results suggest that Cg infection makes the lung microenvironment favourable for Sp colonization and dissemination. Altogether, it leads to an exacerbated and ineffective inflammatory response, decisive for the increased morbidity and mortality during coinfection. In conclusion, our results highlight the importance of more studies addressing coinfections and their consequences in the host, aiming to establish more effective therapeutical strategies.
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Affiliation(s)
- Bárbara A Miranda
- Departamento de Microbiologia/Laboratório de Micologia, Universidade Federal de Minas Gerais, Belo Horizonte, Brazil
| | - Gustavo J C Freitas
- Departamento de Microbiologia/Laboratório de Micologia, Universidade Federal de Minas Gerais, Belo Horizonte, Brazil
| | - Victor A T Leocádio
- Departamento de Microbiologia/Laboratório de Micologia, Universidade Federal de Minas Gerais, Belo Horizonte, Brazil
| | - Marliete C Costa
- Departamento de Microbiologia/Laboratório de Micologia, Universidade Federal de Minas Gerais, Belo Horizonte, Brazil
| | - Elúzia C P Emídio
- Departamento de Microbiologia/Laboratório de Micologia, Universidade Federal de Minas Gerais, Belo Horizonte, Brazil
| | - Noelly Q Ribeiro
- Departamento de Microbiologia/Laboratório de Micologia, Universidade Federal de Minas Gerais, Belo Horizonte, Brazil
| | - Paulo H F Carmo
- Departamento de Microbiologia/Laboratório de Micologia, Universidade Federal de Minas Gerais, Belo Horizonte, Brazil
| | - Ludmila Gouveia-Eufrásio
- Departamento de Microbiologia/Laboratório de Micologia, Universidade Federal de Minas Gerais, Belo Horizonte, Brazil
| | - Josy Hubner
- Departamento de Bioquímica e Imunologia, Universidade Federal de Minas Gerais, Belo Horizonte, Brazil
| | - Luciana P Tavares
- Departamento de Bioquímica e Imunologia, Universidade Federal de Minas Gerais, Belo Horizonte, Brazil
- Pulmonary and Critical Care Medicine Division, Department of Medicine, Brigham and Women's Hospital and Harvard Medical School, Boston, Massachusetts, USA
| | - Raquel D N Arifa
- Departamento de Microbiologia/Laboratório de Micologia, Universidade Federal de Minas Gerais, Belo Horizonte, Brazil
| | - Camila B Brito
- Departamento de Microbiologia/Laboratório de Micologia, Universidade Federal de Minas Gerais, Belo Horizonte, Brazil
| | - Monique F Silva
- Departamento de Patologia/Laboratório de Patologia Celular e Molecular, Universidade Federal de Minas Gerais, Belo Horizonte, Brazil
| | - Mauro M Teixeira
- Departamento de Bioquímica e Imunologia, Universidade Federal de Minas Gerais, Belo Horizonte, Brazil
| | - Tatiane A Paixão
- Departamento de Patologia/Laboratório de Patologia Celular e Molecular, Universidade Federal de Minas Gerais, Belo Horizonte, Brazil
| | - Nalu T A Peres
- Departamento de Microbiologia/Laboratório de Micologia, Universidade Federal de Minas Gerais, Belo Horizonte, Brazil
| | - Caio T Fagundes
- Departamento de Microbiologia/Laboratório de Micologia, Universidade Federal de Minas Gerais, Belo Horizonte, Brazil
| | - Daniel A Santos
- Departamento de Microbiologia/Laboratório de Micologia, Universidade Federal de Minas Gerais, Belo Horizonte, Brazil
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Choy HL, Gaylord EA, Doering TL. Ergosterol distribution controls surface structure formation and fungal pathogenicity. mBio 2023; 14:e0135323. [PMID: 37409809 PMCID: PMC10470819 DOI: 10.1128/mbio.01353-23] [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: 05/30/2023] [Accepted: 06/01/2023] [Indexed: 07/07/2023] Open
Abstract
Ergosterol, the major sterol in fungal membranes, is critical for defining membrane fluidity and regulating cellular processes. Although ergosterol synthesis has been well defined in model yeast, little is known about sterol organization in the context of fungal pathogenesis. We identified a retrograde sterol transporter, Ysp2, in the opportunistic fungal pathogen Cryptococcus neoformans. We found that the lack of Ysp2 under host-mimicking conditions leads to abnormal accumulation of ergosterol at the plasma membrane, invagination of the plasma membrane, and malformation of the cell wall, which can be functionally rescued by inhibiting ergosterol synthesis with the antifungal drug fluconazole. We also observed that cells lacking Ysp2 mislocalize the cell surface protein Pma1 and have abnormally thin and permeable capsules. As a result of perturbed ergosterol distribution and its consequences, ysp2∆ cells cannot survive in physiologically relevant environments such as host phagocytes and are dramatically attenuated in virulence. These findings expand our knowledge of cryptococcal biology and underscore the importance of sterol homeostasis in fungal pathogenesis. IMPORTANCE Cryptococcus neoformans is an opportunistic fungal pathogen that kills over 100,000 people worldwide each year. Only three drugs are available to treat cryptococcosis, and these are variously limited by toxicity, availability, cost, and resistance. Ergosterol is the most abundant sterol in fungi and a key component in modulating membrane behavior. Two of the drugs used for cryptococcal infection, amphotericin B and fluconazole, target this lipid and its synthesis, highlighting its importance as a therapeutic target. We discovered a cryptococcal ergosterol transporter, Ysp2, and demonstrated its key roles in multiple aspects of cryptococcal biology and pathogenesis. These studies demonstrate the role of ergosterol homeostasis in C. neoformans virulence, deepen our understanding of a pathway with proven therapeutic importance, and open a new area of study.
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Affiliation(s)
- Hau Lam Choy
- Department of Molecular Microbiology, Washington University School of Medicine, St. Louis, Missouri, USA
| | - Elizabeth A. Gaylord
- Department of Molecular Microbiology, Washington University School of Medicine, St. Louis, Missouri, USA
| | - Tamara L. Doering
- Department of Molecular Microbiology, Washington University School of Medicine, St. Louis, Missouri, USA
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Yan Y, Wu Y, Wang Q, Zhu X, Li H, Jiang H. Lesion size as a prognostic factor in the antifungal treatment of pulmonary cryptococcosis: a retrospective study with chest CT pictorial review of 2-year follow up. BMC Infect Dis 2023; 23:153. [PMID: 36918805 PMCID: PMC10012437 DOI: 10.1186/s12879-023-08131-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2022] [Accepted: 03/02/2023] [Indexed: 03/16/2023] Open
Abstract
BACKGROUND Pulmonary cryptococcosis (PC) is a fungal infection that can have a variable prognosis depending on several factors. The objective of this study was to analyse the characteristics of pulmonary lesions and identify prognostic factors in patients with PC who were human immunodeficiency virus (HIV) -negative and underwent antifungal treatment. METHODS The study enrolled patients diagnosed with PC who were negative for HIV. Symptoms, CT characteristics of pulmonary lesions, serum cryptococcal capsular antigen (CrAg) titre, underlying diseases, and duration of antifungal treatment were evaluated over a 2-year follow-up. RESULTS A total of 63 patients (40 men and 23 women) with a mean age of 50.4 years were included. Half of the patients (50.8%) were asymptomatic, and the most common symptoms were cough (44.4%), expectoration (27.0%), and fever (17.5%). Pulmonary lesions were mainly present in the peripheral and lower lobes of the lung, with 35 cases classified as nodular-type lesions and 28 cases classified as mass-type lesions. At the first, third, sixth, 12th, and 24th-month follow-ups, the median proportion of residual pulmonary lesions were 59.6%, 29.9%, 12.2%, 9.6%, and 0.0%, respectively. During antifungal treatment, the lesions of 33 patients achieved complete response, while the remaining 30 patients did not. Compared with the non-CR group, the CR group had a lower baseline serum CrAg titre (median, 1:20 vs 1:80, P < 0.01), smaller pulmonary lesion size (median area, 1.6 cm2 vs 6.3 cm2, P < 0.01), lower Hounsfield-units (HU) radiodensity (median, - 60.0 HU vs - 28.5 HU, P < 0.05), more nodular-type lesions (72.7% vs 36.7%, P < 0.01), and fewer air-bronchogram signs (18.2% vs 43.3%, P < 0.05). Multivariate logistic regression analysis showed that a larger lesion size on chest CT scans was associated with a lower likelihood of achieving complete response [OR: 0.89; 95% CI (0.81-0.97); P < 0.05]. CONCLUSIONS PC was more commonly observed in HIV-negative men, and chest CT scans mostly revealed nodular-type lesions. After antifungal treatment, patients with smaller lesions had a better prognosis.
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Affiliation(s)
- Yu Yan
- Department of Pulmonary and Critical Care Medicine, Zhongshan Hospital, Fudan University, Shanghai, 200032, China
| | - Yuxiao Wu
- Department of Pulmonary and Critical Care Medicine, Zhongshan Hospital, Fudan University, Shanghai, 200032, China
| | - Qin Wang
- Department of Pulmonary and Critical Care Medicine, Zhongshan Hospital, Fudan University, Shanghai, 200032, China
| | - Xiaodan Zhu
- Department of Pulmonary and Critical Care Medicine, Zhongshan Hospital, Fudan University, Shanghai, 200032, China
| | - Huayin Li
- Department of Pulmonary and Critical Care Medicine, Zhongshan Hospital, Fudan University, Shanghai, 200032, China
| | - Hongni Jiang
- Department of Pulmonary and Critical Care Medicine, Zhongshan Hospital, Fudan University, Shanghai, 200032, China. .,Department of Pulmonary Medicine, Zhongshan Hospital (Xiamen), Fudan University, Xiamen, Fujian, 361015, China.
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7
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Choy HL, Gaylord EA, Doering TL. Ergosterol distribution controls surface structure formation and fungal pathogenicity. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.02.17.528979. [PMID: 36824733 PMCID: PMC9949117 DOI: 10.1101/2023.02.17.528979] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/19/2023]
Abstract
Ergosterol, the major sterol in fungal membranes, is critical for defining membrane fluidity and regulating cellular processes. Although ergosterol synthesis has been well defined in model yeast, little is known about sterol organization in the context of fungal pathogenesis. We identified a retrograde sterol transporter, Ysp2, in the opportunistic fungal pathogen Cryptococcus neoformans . We found that the lack of Ysp2 under host-mimicking conditions leads to abnormal accumulation of ergosterol at the plasma membrane, invagination of the plasma membrane, and malformation of the cell wall, which can be functionally rescued by inhibiting ergosterol synthesis with the antifungal drug fluconazole. We also observed that cells lacking Ysp2 mislocalize the cell surface protein Pma1 and have thinner and more permeable capsules. As a result of perturbed ergosterol distribution and its consequences, ysp2 Î" cells cannot survive in physiologically-rele-vant environments such as host phagocytes and are dramatically attenuated in virulence. These findings expand our knowledge of cryptococcal biology and underscore the importance of sterol homeostasis in fungal pathogenesis. IMPORTANCE Cryptococcus neoformans is an opportunistic fungal pathogen that kills over 100,000 people worldwide each year. Only three drugs are available to treat cryptococcosis, and these are variously limited by toxicity, availability, cost, and resistance. Ergosterol is the most abundant sterol in fungi and a key component in modulating membrane behavior. Two of the drugs used for cryptococcal infection, amphotericin B and fluconazole, target this lipid and its synthesis, highlighting its importance as a therapeutic target. We discovered a cryptococcal ergosterol transporter, Ysp2, and demonstrated its key roles in multiple aspects of cryptococcal biology and pathogenesis. These studies demonstrate the role of ergosterol homeostasis in C. neoformans virulence, deepen our understanding of a pathway with proven therapeutic importance, and open a new area of study.
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Affiliation(s)
- Hau Lam Choy
- Department of Molecular Microbiology, Washington University School of Medicine, St. Louis, Missouri, USA
| | - Elizabeth A. Gaylord
- Department of Molecular Microbiology, Washington University School of Medicine, St. Louis, Missouri, USA
| | - Tamara L. Doering
- Department of Molecular Microbiology, Washington University School of Medicine, St. Louis, Missouri, USA
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8
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Regulatory basis for reproductive flexibility in a meningitis-causing fungal pathogen. Nat Commun 2022; 13:7938. [PMID: 36566249 PMCID: PMC9790007 DOI: 10.1038/s41467-022-35549-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2022] [Accepted: 12/09/2022] [Indexed: 12/25/2022] Open
Abstract
Pathogenic fungi of the genus Cryptococcus can undergo two sexual cycles, involving either bisexual diploidization (after fusion of haploid cells of different mating type) or unisexual diploidization (by autodiploidization of a single cell). Here, we construct a gene-deletion library for 111 transcription factor genes in Cryptococcus deneoformans, and explore the roles of these regulatory networks in the two reproductive modes. We show that transcription factors crucial for bisexual syngamy induce the expression of known mating determinants as well as other conserved genes of unknown function. Deletion of one of these genes, which we term FMP1, leads to defects in bisexual reproduction in C. deneoformans, its sister species Cryptococcus neoformans, and the ascomycete Neurospora crassa. Furthermore, we show that a recently evolved regulatory cascade mediates pre-meiotic unisexual autodiploidization, supporting that this reproductive process is a recent evolutionary innovation. Our findings indicate that genetic circuits with different evolutionary ages govern hallmark events distinguishing unisexual and bisexual reproduction in Cryptococcus.
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9
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The Dynamics of Cryptococcus neoformans Cell and Transcriptional Remodeling during Infection. Cells 2022; 11:cells11233896. [PMID: 36497155 PMCID: PMC9740611 DOI: 10.3390/cells11233896] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2022] [Revised: 11/24/2022] [Accepted: 11/29/2022] [Indexed: 12/03/2022] Open
Abstract
The phenotypic plasticity of Cryptococcus neoformans is widely studied and demonstrated in vitro, but its influence on pathogenicity remains unclear. In this study, we investigated the dynamics of cryptococcal cell and transcriptional remodeling during pulmonary infection in a murine model. We showed that in Cryptococcus neoformans, cell size reduction (cell body ≤ 3 µm) is important for initial adaptation during infection. This change was associated with reproductive fitness and tissue invasion. Subsequently, the fungus develops mechanisms aimed at resistance to the host’s immune response, which is determinant for virulence. We investigated the transcriptional changes involved in this cellular remodeling and found an upregulation of transcripts related to ribosome biogenesis at the beginning (6 h) of infection and a later (10 days) upregulation of transcripts involved in the inositol pathway, energy production, and the proteasome. Consistent with a role for the proteasome, we found that its inhibition delayed cell remodeling during infection with the H99 strain. Altogether, these results further our understanding of the infection biology of C. neoformans and provide perspectives to support therapeutic and diagnostic targets for cryptococcosis.
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10
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Hu Q, Li X, Zhou X, Zhao C, Zheng C, Xu L, Zhou Z. Clinical utility of cryptococcal antigen detection in transthoracic needle aspirate by lateral flow assay for diagnosing non-HIV pulmonary cryptococcosis: A multicenter retrospective study. Medicine (Baltimore) 2022; 101:e30572. [PMID: 36123876 PMCID: PMC9478314 DOI: 10.1097/md.0000000000030572] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/26/2022] Open
Abstract
Lateral flow immunoassay (LFA) detection of cryptococcal capsular polysaccharide antigen (CrAg) is reported to be the most rapid and convenient laboratory method for diagnosing cryptococcosis. Its clinical diagnostic use, however, is not well studied. We retrospectively analyzed the data from 97 patients with suspected pulmonary cryptococcosis (PC) at 2 tertiary care centers. CrAg in both serum and lung aspirate specimens were examined by LFA. We divided the patients who were diagnosed with PC into group I, patients positive for CrAg in both the serum and lung aspirate, and group II, patients positive for CrAg in the lung aspirate but not in the serum. We analyzed the differences in imaging distribution, morphological characteristics, and concomitant signs between the 2 groups. Of all 97 patients, 47 were diagnosed with PC. Lung aspirates were positive for CrAg in 46/47 patients with PC (sensitivity 97.9%, specificity 100%, positive predictive value = 100%, negative predictive value = 98%). There were no false positive results in the noncryptococcosis patients, revealing a diagnostic accuracy of 99%. Serum CrAg tests were positive in 36/47 patients with PC (sensitivity 76.6%, specificity 100%, accuracy 88.7%, positive predictive value = 100%, negative predictive value = 82%). Chest imaging data showed a statistically significant greater number of single lesions in group II than in group I (P < .05). More lesions accompanied by halo signs were showed in group I (P < .01), whereas more accompanied by pleural stretch signs were found in group II (P < .01). The LFA-positive rate of CrAg in lung aspirate samples was higher than that of the serum samples, especially in patients with single pulmonary lesion or in those accompanied by pleural stretch. The direct measurement of CrAg in lung aspirate is a rapid, useful alternative diagnostic method for PC confirmation.
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Affiliation(s)
- Qun Hu
- Department of Pulmonary and Critical Care Medicine, South China Hospital of Shenzhen University, Shenzhen, China
| | - Xiaohua Li
- Department of Pulmonary and Critical Care Medicine, Fuzhou first hospital, Fujian Medical University, Fuzhou, China
| | - Xiao Zhou
- Department of Pulmonary and Critical Care Medicine, Fuzhou General Clinical Medical College, Fujian Medical University, Fuzhou, China
| | - Chunlei Zhao
- Medical Imaging Center, Fuzhou General Clinical Medical College, Fujian Medical University, Fuzhou, China
| | - Caixia Zheng
- Department of imaging Medicine, Fuzhou First Hospital, Fujian Medical University, Fuzhou, China
| | - Liyu Xu
- Department of Pulmonary and Critical Care Medicine, Fuzhou first hospital, Fujian Medical University, Fuzhou, China
- *Correspondence: Liyu Xu, MD, PhD, Department of Pulmonary and Critical Care Medicine, Fuzhou City First Hospital, Fujian Medical University, Fuzhou 350009, China (e-mail: ); Zizi Zhou, MD, Department of Cardiothoracic Surgery, Shenzhen University General Hospital, Shenzhen, 518055, China (e-mail: )
| | - Zizi Zhou
- Department of Cardiothoracic Surgery, Shenzhen University General Hospital, Shenzhen, China
- *Correspondence: Liyu Xu, MD, PhD, Department of Pulmonary and Critical Care Medicine, Fuzhou City First Hospital, Fujian Medical University, Fuzhou 350009, China (e-mail: ); Zizi Zhou, MD, Department of Cardiothoracic Surgery, Shenzhen University General Hospital, Shenzhen, 518055, China (e-mail: )
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11
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Saidykhan L, Correia J, Romanyuk A, Peacock AFA, Desanti GE, Taylor-Smith L, Makarova M, Ballou ER, May RC. An in vitro method for inducing titan cells reveals novel features of yeast-to-titan switching in the human fungal pathogen Cryptococcus gattii. PLoS Pathog 2022; 18:e1010321. [PMID: 35969643 PMCID: PMC9426920 DOI: 10.1371/journal.ppat.1010321] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2022] [Revised: 08/30/2022] [Accepted: 07/07/2022] [Indexed: 12/15/2022] Open
Abstract
Cryptococcosis is a potentially lethal fungal infection of humans caused by organisms within the Cryptococcus neoformans/gattii species complex. Whilst C. neoformans is a relatively common pathogen of immunocompromised individuals, C. gattii is capable of acting as a primary pathogen of immunocompetent individuals. Within the host, both species undergo morphogenesis to form titan cells: exceptionally large cells that are critical for disease establishment. To date, the induction, defining attributes, and underlying mechanism of titanisation have been mainly characterized in C. neoformans. Here, we report the serendipitous discovery of a simple and robust protocol for in vitro induction of titan cells in C. gattii. Using this in vitro approach, we reveal a remarkably high capacity for titanisation within C. gattii, especially in strains associated with the Pacific Northwest Outbreak, and characterise strain-specific differences within the clade. In particular, this approach demonstrates for the first time that cell size changes, DNA amplification, and budding are not always synchronous during titanisation. Interestingly, however, exhibition of these cell cycle phenotypes was correlated with genes associated with cell cycle progression including CDC11, CLN1, BUB2, and MCM6. Finally, our findings reveal exogenous p-Aminobenzoic acid to be a key inducer of titanisation in this organism. Consequently, this approach offers significant opportunities for future exploration of the underlying mechanism of titanisation in this genus.
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Affiliation(s)
- Lamin Saidykhan
- Institute of Microbiology & Infection and School of Biosciences, University of Birmingham, Edgbaston, United Kingdom
- Division of Physical and Natural Science, University of The Gambia, Brikama, The Gambia
| | - Joao Correia
- Institute of Microbiology & Infection and School of Biosciences, University of Birmingham, Edgbaston, United Kingdom
| | - Andrey Romanyuk
- Institute of Microbiology & Infection and School of Biosciences, University of Birmingham, Edgbaston, United Kingdom
- School of Chemistry, University of Birmingham, Edgbaston, United Kingdom
| | - Anna F. A. Peacock
- School of Chemistry, University of Birmingham, Edgbaston, United Kingdom
| | - Guillaume E. Desanti
- Institute of Microbiology & Infection and School of Biosciences, University of Birmingham, Edgbaston, United Kingdom
| | - Leanne Taylor-Smith
- Institute of Microbiology & Infection and School of Biosciences, University of Birmingham, Edgbaston, United Kingdom
| | - Maria Makarova
- Institute of Microbiology & Infection and School of Biosciences, University of Birmingham, Edgbaston, United Kingdom
| | - Elizabeth R. Ballou
- Institute of Microbiology & Infection and School of Biosciences, University of Birmingham, Edgbaston, United Kingdom
- MRC Centre for Medical Mycology, University of Exeter, Exeter, United Kingdom
- * E-mail: (ERB); (RCM)
| | - Robin C. May
- Institute of Microbiology & Infection and School of Biosciences, University of Birmingham, Edgbaston, United Kingdom
- * E-mail: (ERB); (RCM)
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12
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Saravanakumar K, Santosh SS, Ahamed MA, Sathiyaseelan A, Sultan G, Irfan N, Ali DM, Wang MH. Bioinformatics strategies for studying the molecular mechanisms of fungal extracellular vesicles with a focus on infection and immune responses. Brief Bioinform 2022; 23:6632620. [PMID: 35794708 DOI: 10.1093/bib/bbac250] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2022] [Revised: 05/16/2022] [Accepted: 05/28/2022] [Indexed: 01/19/2023] Open
Abstract
Fungal extracellular vesicles (EVs) are released during pathogenesis and are found to be an opportunistic infection in most cases. EVs are immunocompetent with their host and have paved the way for new biomedical approaches to drug delivery and the treatment of complex diseases including cancer. With computing and processing advancements, the rise of bioinformatics tools for the evaluation of various parameters involved in fungal EVs has blossomed. In this review, we have complied and explored the bioinformatics tools to analyze the host-pathogen interaction, toxicity, omics and pathogenesis with an array of specific tools that have depicted the ability of EVs as vector/carrier for therapeutic agents and as a potential theme for immunotherapy. We have also discussed the generation and pathways involved in the production, transport, pathogenic action and immunological interactions of EVs in the host system. The incorporation of network pharmacology approaches has been discussed regarding fungal pathogens and their significance in drug discovery. To represent the overview, we have presented and demonstrated an in silico study model to portray the human Cryptococcal interactions.
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Affiliation(s)
- Kandasamy Saravanakumar
- Department of Bio-Health convergence, Kangwon National University, Chuncheon 200-701, Republic of Korea
| | | | - MohamedAli Afaan Ahamed
- School of Life Sciences, B.S. Abdur Rahman Crescent Institute of Science and Technology, Chennai, Tamil Nadu 600048, India
| | - Anbazhagan Sathiyaseelan
- Department of Bio-Health convergence, Kangwon National University, Chuncheon 200-701, Republic of Korea
| | - Ghazala Sultan
- Department of Computer Science, Aligarh Muslim University, Aligarh, Uttar Pradesh, 202002, India
| | - Navabshan Irfan
- Crescent School of Pharmacy, B.S Abdur Rahman Crescent Institute of Science and Technology, Chennai, 600048, India
| | - Davoodbasha Mubarak Ali
- School of Life Sciences, B.S. Abdur Rahman Crescent Institute of Science and Technology, Chennai, Tamil Nadu 600048, India
| | - Myeong-Hyeon Wang
- Department of Bio-Health convergence, Kangwon National University, Chuncheon 200-701, Republic of Korea
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13
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Yang YL, Fan YB, Gao L, Zhang C, Gu JL, Pan WH, Fang W. Cryptococcus neoformans Csn1201 Is Associated With Pulmonary Immune Responses and Disseminated Infection. Front Immunol 2022; 13:890258. [PMID: 35720283 PMCID: PMC9201341 DOI: 10.3389/fimmu.2022.890258] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2022] [Accepted: 05/09/2022] [Indexed: 11/21/2022] Open
Abstract
Cryptococcus neoformans is a major etiological agent of fungal meningoencephalitis. The outcome of cryptococcosis depends on the complex interactions between the pathogenic fungus and host immunity. The understanding of how C. neoformans manipulates the host immune response through its pathogenic factors remains incomplete. In this study, we defined the roles of a previously uncharacterized protein, Csn1201, in cryptococcal fitness and host immunity. Use of both inhalational and intravenous mouse models demonstrated that the CSN1201 deletion significantly blocked the pulmonary infection and extrapulmonary dissemination of C. neoformans. The in vivo hypovirulent phenotype of the csn1201Δ mutant was attributed to a combination of multiple factors, including preferential dendritic cell accumulation, enhanced Th1 and Th17 immune responses, decreased intracellular survival inside macrophages, and attenuated blood–brain barrier transcytosis rather than exclusively to pathogenic fitness. The csn1201Δ mutant exhibited decreased tolerance to various stressors in vitro, along with reduced capsule production and enhanced cell wall thickness under host-relevant conditions, indicating that the CSN1201 deletion might promote the exposure of cell wall components and thus induce a protective immune response. Taken together, our results strongly support the importance of cryptococcal Csn1201 in pulmonary immune responses and disseminated infection.
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Affiliation(s)
- Ya-Li Yang
- Department of Dermatology, Shanghai Ninth People's Hospital, Shanghai JiaoTong University School of Medicine, Shanghai, China.,Department of Laser and Aesthetic Medicine, Shanghai Ninth People's Hospital, Shanghai JiaoTong University School of Medicine, Shanghai, China.,Shanghai Key Laboratory of Molecular Medical Mycology, Department of Dermatology and Venereology, Changzheng Hospital, Naval Military Medical University, Shanghai, China
| | - Yi-Bin Fan
- Department of Dermatology, Zhejiang Provincial People's Hospital, People's Hospital of Hangzhou Medical College, Hangzhou, China
| | - Lei Gao
- Microscopy Core Facility, Biomedical Research Core Facilities, Westlake University, Hangzhou, China
| | - Chao Zhang
- Shanghai Key Laboratory of Molecular Medical Mycology, Department of Dermatology and Venereology, Changzheng Hospital, Naval Military Medical University, Shanghai, China
| | - Ju-Lin Gu
- Department of Dermatology, Third Affiliated Hospital of Naval Military Medical University, Shanghai, China
| | - Wei-Hua Pan
- Shanghai Key Laboratory of Molecular Medical Mycology, Department of Dermatology and Venereology, Changzheng Hospital, Naval Military Medical University, Shanghai, China
| | - Wei Fang
- Department of Laser and Aesthetic Medicine, Shanghai Ninth People's Hospital, Shanghai JiaoTong University School of Medicine, Shanghai, China.,Shanghai Key Laboratory of Molecular Medical Mycology, Department of Dermatology and Venereology, Changzheng Hospital, Naval Military Medical University, Shanghai, China
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14
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Li Y, Li H, Sun T, Ding C. Pathogen-Host Interaction Repertoire at Proteome and Posttranslational Modification Levels During Fungal Infections. Front Cell Infect Microbiol 2021; 11:774340. [PMID: 34926320 PMCID: PMC8674643 DOI: 10.3389/fcimb.2021.774340] [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: 09/11/2021] [Accepted: 11/15/2021] [Indexed: 12/22/2022] Open
Abstract
Prevalence of fungal diseases has increased globally in recent years, which often associated with increased immunocompromised patients, aging populations, and the novel Coronavirus pandemic. Furthermore, due to the limitation of available antifungal agents mortality and morbidity rates of invasion fungal disease remain stubbornly high, and the emergence of multidrug-resistant fungi exacerbates the problem. Fungal pathogenicity and interactions between fungi and host have been the focus of many studies, as a result, lots of pathogenic mechanisms and fungal virulence factors have been identified. Mass spectrometry (MS)-based proteomics is a novel approach to better understand fungal pathogenicities and host–pathogen interactions at protein and protein posttranslational modification (PTM) levels. The approach has successfully elucidated interactions between pathogens and hosts by examining, for example, samples of fungal cells under different conditions, body fluids from infected patients, and exosomes. Many studies conclude that protein and PTM levels in both pathogens and hosts play important roles in progression of fungal diseases. This review summarizes mass spectrometry studies of protein and PTM levels from perspectives of both pathogens and hosts and provides an integrative conceptual outlook on fungal pathogenesis, antifungal agents development, and host–pathogen interactions.
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Affiliation(s)
- Yanjian Li
- College of Life and Health Sciences, Northeastern University, Shenyang, China
| | - Hailong Li
- NHC Key Laboratory of AIDS Immunology (China Medical University), National Clinical Research Center for Laboratory Medicine, The First Affiliated Hospital of China Medical University, Shenyang, China
| | - Tianshu Sun
- Medical Research Centre, State Key Laboratory of Complex Severe and Rare Diseases, Peking Union Medical College Hospital, Chinese Academy of Medical Science, Beijing, China.,Beijing Key Laboratory for Mechanisms Research and Precision Diagnosis of Invasive Fungal Diseases, Beijing, China
| | - Chen Ding
- College of Life and Health Sciences, Northeastern University, Shenyang, China
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15
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Romani L, Williamson PR, Di Cesare S, Di Matteo G, De Luca M, Carsetti R, Figà-Talamanca L, Cancrini C, Rossi P, Finocchi A. Cryptococcal Meningitis and Post-Infectious Inflammatory Response Syndrome in a Patient With X-Linked Hyper IgM Syndrome: A Case Report and Review of the Literature. Front Immunol 2021; 12:708837. [PMID: 34335625 PMCID: PMC8320724 DOI: 10.3389/fimmu.2021.708837] [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: 05/12/2021] [Accepted: 06/25/2021] [Indexed: 12/27/2022] Open
Abstract
The hyper IgM syndromes are a rare group of primary immunodeficiency. The X-linked Hyper IgM syndrome (HIGM), due to a gene defect in CD40L, is the commonest variant; it is characterized by an increased susceptibility to a narrow spectrum of opportunistic infection. A few cases of HIGM patients with Cryptococcal meningoencephalitis (CM) have been described in the literature. Herein we report the case of a young male diagnosed in infancy with HIGM who developed CM complicated by a post-infectious inflammatory response syndrome (PIIRS), despite regular immunoglobulin replacement therapy and appropriate antimicrobial prophylaxis. The patient was admitted because of a headache and CM was diagnosed through detection of Cryptococcus neoformans in the cerebrospinal fluid. Despite the antifungal therapy resulting to negative CSF culture, the patient exhibited persistent headaches and developed diplopia. An analysis of inflammatory cytokines on CSF, as well as the brain MRI, suggested a diagnosis of PIIRS. Therefore, a prolonged corticosteroids therapy was started obtaining a complete resolution of symptoms without any relapse.
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Affiliation(s)
- Lorenza Romani
- Unit of Immune and Infectious Diseases, Bambino Gesu' Children's Hospital, IRCCS, Rome, Italy
| | - Peter Richard Williamson
- Laboratory of Clinical Immunology and Microbiology, National Institutes of Health, Bethesda, MD, United States
| | - Silvia Di Cesare
- Department of Systems Medicine, University of Rome Tor Vergata, Rome, Italy
| | - Gigliola Di Matteo
- Department of Systems Medicine, University of Rome Tor Vergata, Rome, Italy
| | - Maia De Luca
- Unit of Immune and Infectious Diseases, Bambino Gesu' Children's Hospital, IRCCS, Rome, Italy
| | - Rita Carsetti
- B Cell Physiopathology Unit, Immunology Research Area, Bambino Gesu' Children's Hospital, IRCCS, Rome, Italy
| | - Lorenzo Figà-Talamanca
- Neuroradiology Unit, Imaging Department, Bambino Gesu' Children's Hospital, IRCCS, Rome, Italy
| | - Caterina Cancrini
- Unit of Immune and Infectious Diseases, Bambino Gesu' Children's Hospital, IRCCS, Rome, Italy.,Department of Systems Medicine, University of Rome Tor Vergata, Rome, Italy
| | - Paolo Rossi
- Unit of Immune and Infectious Diseases, Bambino Gesu' Children's Hospital, IRCCS, Rome, Italy.,Department of Systems Medicine, University of Rome Tor Vergata, Rome, Italy
| | - Andrea Finocchi
- Unit of Immune and Infectious Diseases, Bambino Gesu' Children's Hospital, IRCCS, Rome, Italy.,Department of Systems Medicine, University of Rome Tor Vergata, Rome, Italy
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16
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Yamamura D, Xu J. Update on Pulmonary Cryptococcosis. Mycopathologia 2021; 186:717-728. [PMID: 34181160 DOI: 10.1007/s11046-021-00575-9] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2020] [Accepted: 06/22/2021] [Indexed: 12/24/2022]
Abstract
Pulmonary cryptococcosis is a common but underdiagnosed opportunistic fungal infection in both immunocompromised and immunocompetent patients. The causal agents include at least eight evolutionary distinct haploid lineages as well as their hybrids of the human pathogenic Cryptococcus complex. In this update, we review recent advances in epidemiology, mode of transmission, risk factors, diagnostic methods, and therapy of pulmonary cryptococcosis. Our review suggests significant challenges and opportunities for research, from bedside to benchside and back to bedside.
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Affiliation(s)
- Deborah Yamamura
- Microbiology Department, Hamilton Regional Laboratory Medicine Program, Hamilton General Hospital, Hamilton, ON, L8L 2X2, Canada.,Department of Pathology and Molecular Medicine, McMaster University, Hamilton, L8S 4K1, Canada
| | - Jianping Xu
- Department of Biology, McMaster University, Hamilton, L8S 4K1, Canada.
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17
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Squizani ED, Reuwsaat JC, Motta H, Tavanti A, Kmetzsch L. Calcium: a central player in Cryptococcus biology. FUNGAL BIOL REV 2021. [DOI: 10.1016/j.fbr.2021.03.004] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
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18
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The Transcription Factor Pdr802 Regulates Titan Cell Formation and Pathogenicity of Cryptococcus neoformans. mBio 2021; 12:mBio.03457-20. [PMID: 33688010 PMCID: PMC8092302 DOI: 10.1128/mbio.03457-20] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
The pathogenic yeast Cryptococcus neoformans presents a worldwide threat to human health, especially in the context of immunocompromise, and current antifungal therapy is hindered by cost, limited availability, and inadequate efficacy. After the infectious particle is inhaled, C. neoformans initiates a complex transcriptional program that integrates cellular responses and enables adaptation to the host lung environment. Cryptococcus neoformans is a ubiquitous, opportunistic fungal pathogen that kills almost 200,000 people worldwide each year. It is acquired when mammalian hosts inhale the infectious propagules; these are deposited in the lung and, in the context of immunocompromise, may disseminate to the brain and cause lethal meningoencephalitis. Once inside the host, C. neoformans undergoes a variety of adaptive processes, including secretion of virulence factors, expansion of a polysaccharide capsule that impedes phagocytosis, and the production of giant (Titan) cells. The transcription factor Pdr802 is one regulator of these responses to the host environment. Expression of the corresponding gene is highly induced under host-like conditions in vitro and is critical for C. neoformans dissemination and virulence in a mouse model of infection. Direct targets of Pdr802 include the quorum sensing proteins Pqp1, Opt1, and Liv3; the transcription factors Stb4, Zfc3, and Bzp4, which regulate cryptococcal brain infectivity and capsule thickness; the calcineurin targets Had1 and Crz1, important for cell wall remodeling and C. neoformans virulence; and additional genes related to resistance to host temperature and oxidative stress, and to urease activity. Notably, cryptococci engineered to lack Pdr802 showed a dramatic increase in Titan cells, which are not phagocytosed and have diminished ability to directly cross biological barriers. This explains the limited dissemination of pdr802 mutant cells to the central nervous system and the consequently reduced virulence of this strain. The role of Pdr802 as a negative regulator of Titan cell formation is thus critical for cryptococcal pathogenicity.
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19
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Normile TG, Bryan AM, Del Poeta M. Animal Models of Cryptococcus neoformans in Identifying Immune Parameters Associated With Primary Infection and Reactivation of Latent Infection. Front Immunol 2020; 11:581750. [PMID: 33042164 PMCID: PMC7522366 DOI: 10.3389/fimmu.2020.581750] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2020] [Accepted: 08/12/2020] [Indexed: 12/13/2022] Open
Abstract
Cryptococcus species are environmental fungal pathogens and the causative agents of cryptococcosis. Infection occurs upon inhalation of infectious particles, which proliferate in the lung causing a primary infection. From this primary lung infection, fungal cells can eventually disseminate to other organs, particularly the brain, causing lethal meningoencephalitis. However, in most cases, the primary infection resolves with the formation of a lung granuloma. Upon severe immunodeficiency, dormant cryptococcal cells will start proliferating in the lung granuloma and eventually will disseminate to the brain. Many investigators have sought to study the protective host immune response to this pathogen in search of host parameters that keep the proliferation of cryptococcal cells under control. The majority of the work assimilates research carried out using the primary infection animal model, mainly because a reactivation model has been available only very recently. This review will focus on anti-cryptococcal immunity in both the primary and reactivation models. An understanding of the differences in host immunity between the primary and reactivation models will help to define the key host parameters that control the infections and are important for the research and development of new therapeutic and vaccine strategies against cryptococcosis.
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Affiliation(s)
- Tyler G Normile
- Department of Microbiology and Immunology, Stony Brook University, Stony Brook, NY, United States
| | - Arielle M Bryan
- Ingenious Targeting Laboratory Incorporated, Ronkonkoma, NY, United States
| | - Maurizio Del Poeta
- Department of Microbiology and Immunology, Stony Brook University, Stony Brook, NY, United States.,Division of Infectious Diseases, School of Medicine, Stony Brook University, Stony Brook, NY, United States.,Veterans Administration Medical Center, Northport, NY, United States
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20
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Silva E Souza E, Barcellos VDA, Sbaraini N, Reuwsaat JCV, Schneider RDO, da Silva AC, Garcia AWA, von Poser GL, Barbosa EG, Lima JPMS, Vainstein MH. A Plumieridine-Rich Fraction From Allamanda polyantha Inhibits Chitinolytic Activity and Exhibits Antifungal Properties Against Cryptococcus neoformans. Front Microbiol 2020; 11:2058. [PMID: 32983042 PMCID: PMC7483551 DOI: 10.3389/fmicb.2020.02058] [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: 02/28/2020] [Accepted: 08/05/2020] [Indexed: 12/28/2022] Open
Abstract
Cryptococcosis is a fungal infection caused mainly by the pathogenic yeasts Cryptococcus neoformans and Cryptococcus gattii. The infection initiates with the inhalation of propagules that are then deposited in the lungs. If not properly treated, cryptococci cells can disseminate and reach the central nervous system. The current recommended treatment for cryptococcosis employs a three-stage regimen, with the administration of amphotericin B, flucytosine and fluconazole. Although effective, these drugs are often unavailable worldwide, can lead to resistance development, and may display toxic effects on the patients. Thus, new drugs for cryptococcosis treatment are needed. Recently, an iridoid named plumieridine was found in Allamanda polyantha seed extract; it exhibited antifungal activity against C. neoformans with a MIC of 250 μg/mL. To address the mode of action of plumieridine, several in silico and in vitro experiments were performed. Through a ligand-based a virtual screening approach, chitinases were identified as potential targets. Confirmatory in vitro assays showed that C. neoformans cell-free supernatant incubated with plumieridine displayed reduced chitinase activity, while chitinolytic activity was not inhibited in the insoluble cell fraction. Additionally, confocal microscopy revealed changes in the distribution of chitooligomers in the cryptococcal cell wall, from a polarized to a diffuse cell pattern state. Remarkably, further assays have shown that plumieridine can also inhibit the chitinolytic activity from the supernatant and cell-free extracts of bacteria, insect and mouse-derived macrophage cells (J774.A1). Together, our results suggest that plumieridine can be a broad-spectrum chitinase inhibitor.
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Affiliation(s)
- Eden Silva E Souza
- Bioinformatics Multidisciplinary Environment, Universidade Federal do Rio Grande do Norte, Natal, Brazil
| | | | - Nicolau Sbaraini
- Centro de Biotecnologia, Universidade Federal do Rio Grande do Sul, Porto Alegre, Brazil
| | | | | | - Adriana Corrêa da Silva
- Centro de Biotecnologia, Universidade Federal do Rio Grande do Sul, Porto Alegre, Brazil.,Centro de Ciências Biológicas, Universidade Federal de Santa Catarina, Florianópolis, Brazil
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21
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Martho KF, Brustolini OJB, Vasconcelos AT, Vallim MA, Pascon RC. The Glycerol Phosphatase Gpp2: A Link to Osmotic Stress, Sulfur Assimilation and Virulence in Cryptococcus neoformans. Front Microbiol 2019; 10:2728. [PMID: 31849880 PMCID: PMC6901960 DOI: 10.3389/fmicb.2019.02728] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2019] [Accepted: 11/08/2019] [Indexed: 12/13/2022] Open
Abstract
Cryptococcus neoformans is an opportunist fungal pathogen that causes meningoencephalitis in immunocompromised patients. During infection, this basidiomycete yeast has to adapt to several adverse conditions, especially nutrient availability. The interruption on various amino acid biosynthetic pathways and on amino acid uptake causes reduced viability, inability to cope with various stresses, failure in virulence factors expression and avirulence in animal model of infection. The sulfur amino acid biosynthesis and uptake is an important feature for pathogen survival in vivo and in vitro. Our previous work demonstrates that C. neoformans Cys3 BZip transcription factor controls the gene expression in several steps of the sulfur assimilation and sulfur amino acid biosynthesis. Also, we have shown that Gpp2 phosphatase modulates Cys3 activity. In Saccharomyces cerevisiae Gpp2 is induced in response to hyper osmotic or oxidative stress and during diauxic shift. In this work, we will show that, in C. neoformans, Gpp2 is required to respond to stresses, mainly osmotic stress; also its transcription is induced during exposure to NaCl. Global transcriptional profile of gpp2Δ by RNAseq shows that CYS3 and other genes in the sulfur assimilation pathway are up regulated, which is consistent with our previous report, in which Gpp2 acts by avoiding Cys3 accumulation and nuclear localization. In addition, several transporters genes, especially amino acid permeases and oxidative stress genes are induced in the gpp2Δ strain; on the contrary, genes involved in glucose and tricarboxylic acid metabolism are down regulated. gpp2Δ strain fails to express virulence factors, as melanin, phospholipase, urease and has virulence attenuation in Galleria mellonella. Our data suggest that Gpp2 is an important factor for general pathogen adaptation to various stresses and also to the host, and perhaps it could be an interesting target for therapeutic use.
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Affiliation(s)
- Kevin Felipe Martho
- Department of Biological Sciences, Campus Diadema, Universidade Federal de São Paulo, São Paulo, Brazil
| | - Otávio J B Brustolini
- Laboratório Nacional de Computação Científica - LNCC, Labinfo - Laboratório de Bioinformática, Petrópolis, Brazil
| | - Ana Tereza Vasconcelos
- Laboratório Nacional de Computação Científica - LNCC, Labinfo - Laboratório de Bioinformática, Petrópolis, Brazil
| | - Marcelo A Vallim
- Department of Biological Sciences, Campus Diadema, Universidade Federal de São Paulo, São Paulo, Brazil
| | - Renata C Pascon
- Department of Biological Sciences, Campus Diadema, Universidade Federal de São Paulo, São Paulo, Brazil
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The regulation of the sulfur amino acid biosynthetic pathway in Cryptococcus neoformans: the relationship of Cys3, Calcineurin, and Gpp2 phosphatases. Sci Rep 2019; 9:11923. [PMID: 31417135 PMCID: PMC6695392 DOI: 10.1038/s41598-019-48433-5] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2019] [Accepted: 08/01/2019] [Indexed: 01/02/2023] Open
Abstract
Cryptococcosis is a fungal disease caused by C. neoformans. To adapt and survive in diverse ecological niches, including the animal host, this opportunistic pathogen relies on its ability to uptake nutrients, such as carbon, nitrogen, iron, phosphate, sulfur, and amino acids. Genetic circuits play a role in the response to environmental changes, modulating gene expression and adjusting the microbial metabolism to the nutrients available for the best energy usage and survival. We studied the sulfur amino acid biosynthesis and its implications on C. neoformans biology and virulence. CNAG_04798 encodes a BZip protein and was annotated as CYS3, which has been considered an essential gene. However, we demonstrated that CYS3 is not essential, in fact, its knockout led to sulfur amino acids auxotroph. Western blots and fluorescence microscopy indicated that GFP-Cys3, which is expressed from a constitutive promoter, localizes to the nucleus in rich medium (YEPD); the addition of methionine and cysteine as sole nitrogen source (SD-N + Met/Cys) led to reduced nuclear localization and protein degradation. By proteomics, we identified and confirmed physical interaction among Gpp2, Cna1, Cnb1 and GFP-Cys3. Deletion of the calcineurin and GPP2 genes in a GFP-Cys3 background demonstrated that calcineurin is required to maintain Cys3 high protein levels in YEPD and that deletion of GPP2 causes GFP-Cys3 to persist in the presence of sulfur amino acids. Global transcriptional profile of mutant and wild type by RNAseq revealed that Cys3 controls all branches of the sulfur amino acid biosynthesis, and sulfur starvation leads to induction of several amino acid biosynthetic routes. In addition, we found that Cys3 is required for virulence in Galleria mellonella animal model.
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Hou X, Kou L, Han X, Zhu R, Song L, Liu T. Pulmonary cryptococcosis characteristics in immunocompetent patients-A 20-year clinical retrospective analysis in China. Mycoses 2019; 62:937-944. [PMID: 31287920 PMCID: PMC6852394 DOI: 10.1111/myc.12966] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2019] [Revised: 07/03/2019] [Accepted: 07/05/2019] [Indexed: 12/28/2022]
Abstract
Background Pulmonary cryptococcosis (PC) is not considered an rare, opportunistic infection anymore. The immunocompetent population accounts for an increasing proportion of the morbidity. Objective This study investigated the clinical characteristics of PC patients spanning 20 years, in a referral centre of China. Patients/Methods We retrospectively investigated the clinical data of 99 patients with PC who were diagnosed at Peking Union Medical College Hospital (PUMCH) from January 1998 to December 2017. Results Pulmonary cryptococcosis incidence in PUMCH has seen sharp increase in two decades. There were 40.4% (40/99), 17.2% (17/99) and 42.4% (42/99) immunocompetent, mildly immunocompromised and severe immunocompromised patients, respectively. Significantly higher (P = .035) male predominance in immunocompetent and mildly immunocompromised groups (68.4%, 39/57) compared with severe immunocompromised group (45.2%, 19/42) was found. Overall, 27.5% (11/40) immunocompetent patients reported a significant difference (P = .02) in history of more than weekly drinking, higher than mildly or severe immunocompromised. No significant difference occurred in symptoms and radiographic characteristics among the groups. In pulmonary computerised tomography findings, the non‐air pathway feature was the dominant distribution characteristics in all patients with PC (P = .002). The gap in body dissemination frequency between immunocompetent combined with mildly immunocompromised (5.26%, 3/57) and severe immunocompromised (19.0%, 8/42) was marginally significant (P = .05). Conclusions Gender and alcohol drinking could be PC risk factors of concern in patients without severe immunodeficiency. No significant difference occurred in symptoms or radiographic characteristics between patients with different levels of immune status. The unique radiographic non‐air pathway distribution in the lung may be the feature of Cryptococcus invasion that may enhance accurate diagnosis.
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Affiliation(s)
- Xiaomeng Hou
- Department of Pulmonary Medicine, Peking Union Medical College Hospital, Peking Union Medical College and Chinese Academy of Medical Sciences, Beijing, China
| | - Lei Kou
- Department of Quantitative Health Sciences, Cleveland Clinic, Cleveland, Ohio
| | - Xiaozhen Han
- Department of Quantitative Health Sciences, Cleveland Clinic, Cleveland, Ohio
| | - Rui Zhu
- Department of Medical Record, Peking Union Medical College Hospital, Peking Union Medical College and Chinese Academy of Medical Sciences, Beijing, China
| | - Lan Song
- Department of Radiology, Peking Union Medical College Hospital, Peking Union Medical College and Chinese Academy of Medical Sciences, Beijing, China
| | - Tao Liu
- Department of Pulmonary Medicine, Peking Union Medical College Hospital, Peking Union Medical College and Chinese Academy of Medical Sciences, Beijing, China
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24
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Role of Amino Acid Metabolism in the Virulence of Human Pathogenic Fungi. CURRENT CLINICAL MICROBIOLOGY REPORTS 2019. [DOI: 10.1007/s40588-019-00124-5] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
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25
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Abstract
The acquisition of iron and the maintenance of iron homeostasis are important aspects of virulence for the pathogenic fungus Cryptococcus neoformans In this study, we characterized the role of the monothiol glutaredoxin Grx4 in iron homeostasis and virulence in C. neoformans Monothiol glutaredoxins are important regulators of iron homeostasis because of their conserved roles in [2Fe-2S] cluster sensing and trafficking. We initially identified Grx4 as a binding partner of Cir1, a master regulator of iron-responsive genes and virulence factor elaboration in C. neoformans We confirmed that Grx4 binds Cir1 and demonstrated that iron repletion promotes the relocalization of Grx4 from the nucleus to the cytoplasm. We also found that a grx4 mutant lacking the GRX domain displayed iron-related phenotypes similar to those of a cir1Δ mutant, including poor growth upon iron deprivation. Importantly, the grx4 mutant was avirulent in mice, a phenotype consistent with observed defects in the key virulence determinants, capsule and melanin, and poor growth at 37°C. A comparative transcriptome analysis of the grx4 mutant and the WT strain under low-iron and iron-replete conditions confirmed a central role for Grx4 in iron homeostasis. Dysregulation of iron-related metabolism was consistent with grx4 mutant phenotypes related to oxidative stress, mitochondrial function, and DNA repair. Overall, the phenotypes of the grx4 mutant lacking the GRX domain and the transcriptome sequencing (RNA-Seq) analysis of the mutant support the hypothesis that Grx4 functions as an iron sensor, in part through an interaction with Cir1, to extensively regulate iron homeostasis.IMPORTANCE Fungal pathogens cause life-threatening diseases in humans, particularly in immunocompromised people, and there is a tremendous need for a greater understanding of pathogenesis to support new therapies. One prominent fungal pathogen, Cryptococcus neoformans, causes meningitis in people suffering from HIV/AIDS. In the present study, we focused on characterizing mechanisms by which C. neoformans senses iron availability because iron is both a signal and a key nutrient for proliferation of the pathogen in vertebrate hosts. Specifically, we characterized a monothiol glutaredoxin protein, Grx4, that functions as a sensor of iron availability and interacts with regulatory factors to control the ability of C. neoformans to cause disease. Grx4 regulates key virulence factors, and a mutant is unable to cause disease in a mouse model of cryptococcosis. Overall, our study provides new insights into nutrient sensing and the role of iron in the pathogenesis of fungal diseases.
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26
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Liu L, He GJ, Chen L, Zheng J, Chen Y, Shen L, Tian X, Li E, Yang E, Liao G, Wang L. Genetic basis for coordination of meiosis and sexual structure maturation in Cryptococcus neoformans. eLife 2018; 7:38683. [PMID: 30281018 PMCID: PMC6235564 DOI: 10.7554/elife.38683] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2018] [Accepted: 10/02/2018] [Indexed: 12/19/2022] Open
Abstract
In the human fungal pathogen Cryptococcus neoformans, sex can benefit its pathogenicity through production of meiospores, which are believed to offer both physical and meiosis-created lineage advantages for its infections. Cryptococcus sporulation occurs following two parallel events, meiosis and differentiation of the basidium, the characteristic sexual structure of the basidiomycetes. However, the circuit integrating these events to ensure subsequent sporulation is unclear. Here, we show the spatiotemporal coordination of meiosis and basidial maturation by visualizing event-specific molecules in developing basidia defined by a quantitative approach. Monitoring of gene induction timing together with genetic analysis reveals co-regulation of the coordinated events by a shared regulatory program. Two RRM family regulators, Csa1 and Csa2, are crucial components that bridge meiosis and basidial maturation, further determining sporulation. We propose that the regulatory coordination of meiosis and basidial development serves as a determinant underlying the production of infectious meiospores in C. neoformans.
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Affiliation(s)
- Linxia Liu
- State Key Laboratory of Mycology, Institute of Microbiology, Chinese Academy of Sciences, Beijing, China.,University of Chinese Academy of Sciences, Beijing, China
| | - Guang-Jun He
- State Key Laboratory of Mycology, Institute of Microbiology, Chinese Academy of Sciences, Beijing, China
| | - Lei Chen
- State Key Laboratory of Mycology, Institute of Microbiology, Chinese Academy of Sciences, Beijing, China.,University of Chinese Academy of Sciences, Beijing, China
| | - Jiao Zheng
- College of Pharmaceutical Sciences, Southwest University, Chongqing, China
| | - Yingying Chen
- State Key Laboratory of Mycology, Institute of Microbiology, Chinese Academy of Sciences, Beijing, China.,University of Chinese Academy of Sciences, Beijing, China
| | - Lan Shen
- State Key Laboratory of Mycology, Institute of Microbiology, Chinese Academy of Sciences, Beijing, China
| | - Xiuyun Tian
- State Key Laboratory of Mycology, Institute of Microbiology, Chinese Academy of Sciences, Beijing, China
| | - Erwei Li
- State Key Laboratory of Mycology, Institute of Microbiology, Chinese Academy of Sciences, Beijing, China
| | - Ence Yang
- Department of Microbiology, School of Basic Medical Sciences, Peking University Health Science Center, Beijing, China
| | - Guojian Liao
- College of Pharmaceutical Sciences, Southwest University, Chongqing, China
| | - Linqi Wang
- State Key Laboratory of Mycology, Institute of Microbiology, Chinese Academy of Sciences, Beijing, China.,University of Chinese Academy of Sciences, Beijing, China
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Liu YH, Deng HH, Li HN, Shi TF, Peng HP, Liu AL, Chen W, Hong GL. A DNA electrochemical biosensor based on homogeneous hybridization for the determination of Cryptococcus neoformans. J Electroanal Chem (Lausanne) 2018. [DOI: 10.1016/j.jelechem.2018.09.001] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/28/2022]
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28
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Zhou X, Ballou ER. The Cryptococcus neoformans Titan Cell: From In Vivo Phenomenon to In Vitro Model. CURRENT CLINICAL MICROBIOLOGY REPORTS 2018. [DOI: 10.1007/s40588-018-0107-9] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
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29
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Agustinho DP, Miller LC, Li LX, Doering TL. Peeling the onion: the outer layers of Cryptococcus neoformans. Mem Inst Oswaldo Cruz 2018; 113:e180040. [PMID: 29742198 PMCID: PMC5951675 DOI: 10.1590/0074-02760180040] [Citation(s) in RCA: 38] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2018] [Accepted: 02/27/2018] [Indexed: 12/20/2022] Open
Abstract
Cryptococcus neoformans is an opportunistic fungal pathogen
that is ubiquitous in the environment. It causes a deadly meningitis that is
responsible for over 180,000 deaths worldwide each year, including 15% of all
AIDS-related deaths. The high mortality rates for this infection, even with
treatment, suggest a need for improved therapy. Unique characteristics of
C. neoformans may suggest directions for drug discovery.
These include features of three structures that surround the cell: the plasma
membrane, the cell wall around it, and the outermost polysaccharide capsule. We
review current knowledge of the fundamental biology of these fascinating
structures and highlight open questions in the field, with the goal of
stimulating further investigation that will advance basic knowledge and human
health.
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Affiliation(s)
- Daniel P Agustinho
- Department of Molecular Microbiology, Washington University School of Medicine, St. Louis, Missouri, USA
| | - Liza C Miller
- Department of Molecular Microbiology, Washington University School of Medicine, St. Louis, Missouri, USA
| | - Lucy X Li
- Department of Molecular Microbiology, Washington University School of Medicine, St. Louis, Missouri, USA
| | - Tamara L Doering
- Department of Molecular Microbiology, Washington University School of Medicine, St. Louis, Missouri, USA
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Watkins RA, Andrews A, Wynn C, Barisch C, King JS, Johnston SA. Cryptococcus neoformans Escape From Dictyostelium Amoeba by Both WASH-Mediated Constitutive Exocytosis and Vomocytosis. Front Cell Infect Microbiol 2018; 8:108. [PMID: 29686972 PMCID: PMC5900056 DOI: 10.3389/fcimb.2018.00108] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2017] [Accepted: 03/19/2018] [Indexed: 01/01/2023] Open
Abstract
Cryptococcus neoformans is an environmental yeast that can cause opportunistic infections in humans. As infecting animals does not form part of its normal life-cycle, it has been proposed that the virulence traits that allow cryptococci to resist immune cells were selected through interactions with environmental phagocytes such as amoebae. Here, we investigate the interactions between C. neoformans and the social amoeba Dictyostelium discoideum. We show that like macrophages, D. discoideum is unable to kill C. neoformans upon phagocytosis. Despite this, we find that the yeast pass through the amoebae with an apparently normal phagocytic transit and are released alive by constitutive exocytosis after ~80 min. This is the canonical pathway in amoebae, used to dispose of indigestible material after nutrient extraction. Surprisingly however, we show that upon either genetic or pharmacological blockage of constitutive exocytosis, C. neoformans still escape from D. discoideum by a secondary mechanism. We demonstrate that constitutive exocytosis-independent egress is stochastic and actin-independent. This strongly resembles the non-lytic release of cryptococci by vomocytosis from macrophages, which do not perform constitutive exocytosis and normally retain phagocytosed material. Our data indicate that vomocytosis is functionally redundant for escape from amoebae, which thus may not be the primary driver for its evolutionary selection. Nonetheless, we show that vomocytosis of C. neoformans is mechanistically conserved in hosts ranging from amoebae to man, providing new avenues to understand this poorly-understood but important virulence mechanism.
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Affiliation(s)
- Rhys A. Watkins
- Bateson Centre, University of Sheffield, Sheffield, United Kingdom
- Department of Infection Immunity and Cardiovascular Disease, Medical School, University of Sheffield, Sheffield, United Kingdom
| | - Alexandre Andrews
- Bateson Centre, University of Sheffield, Sheffield, United Kingdom
- Department of Infection Immunity and Cardiovascular Disease, Medical School, University of Sheffield, Sheffield, United Kingdom
| | - Charlotte Wynn
- Bateson Centre, University of Sheffield, Sheffield, United Kingdom
- Department of Infection Immunity and Cardiovascular Disease, Medical School, University of Sheffield, Sheffield, United Kingdom
| | - Caroline Barisch
- Department of Biochemistry, Faculty of Science, University of Geneva, Geneva, Switzerland
| | - Jason S. King
- Bateson Centre, University of Sheffield, Sheffield, United Kingdom
- Department of Biomedical Sciences, University of Sheffield, Sheffield, United Kingdom
| | - Simon A. Johnston
- Bateson Centre, University of Sheffield, Sheffield, United Kingdom
- Department of Infection Immunity and Cardiovascular Disease, Medical School, University of Sheffield, Sheffield, United Kingdom
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Regulated Release of Cryptococcal Polysaccharide Drives Virulence and Suppresses Immune Cell Infiltration into the Central Nervous System. Infect Immun 2018; 86:IAI.00662-17. [PMID: 29203547 PMCID: PMC5820953 DOI: 10.1128/iai.00662-17] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2017] [Accepted: 11/29/2017] [Indexed: 12/22/2022] Open
Abstract
Cryptococcus neoformans is a common environmental yeast and opportunistic pathogen responsible for 15% of AIDS-related deaths worldwide. Mortality primarily results from meningoencephalitis, which occurs when fungal cells disseminate to the brain from the initial pulmonary infection site. A key C. neoformans virulence trait is the polysaccharide capsule. Capsule shields C. neoformans from immune-mediated recognition and destruction. The main capsule component, glucuronoxylomannan (GXM), is found both attached to the cell surface and free in the extracellular space (as exo-GXM). Exo-GXM accumulates in patient serum and cerebrospinal fluid at microgram/milliliter concentrations, has well-documented immunosuppressive properties, and correlates with poor patient outcomes. However, it is poorly understood whether exo-GXM release is regulated or the result of shedding during normal capsule turnover. We demonstrate that exo-GXM release is regulated by environmental cues and inversely correlates with surface capsule levels. We identified genes specifically involved in exo-GXM release that do not alter surface capsule thickness. The first mutant, the liv7Δ strain, released less GXM than wild-type cells when capsule was not induced. The second mutant, the cnag_00658Δ strain, released more exo-GXM under capsule-inducing conditions. Exo-GXM release observed in vitro correlated with polystyrene adherence, virulence, and fungal burden during murine infection. Additionally, we found that exo-GXM reduced cell size and capsule thickness under capsule-inducing conditions, potentially influencing dissemination. Finally, we demonstrated that exo-GXM prevents immune cell infiltration into the brain during disseminated infection and highly inflammatory intracranial infection. Our data suggest that exo-GXM performs a distinct role from capsule GXM during infection, altering cell size and suppressing inflammation.
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Mechanisms of Pulmonary Escape and Dissemination by Cryptococcus neoformans. J Fungi (Basel) 2018; 4:jof4010025. [PMID: 29463005 PMCID: PMC5872328 DOI: 10.3390/jof4010025] [Citation(s) in RCA: 41] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2018] [Revised: 02/09/2018] [Accepted: 02/16/2018] [Indexed: 12/15/2022] Open
Abstract
Cryptococcus neoformans is a common environmental saprophyte and human fungal pathogen that primarily causes disease in immunocompromised individuals. Similar to many environmentally acquired human fungal pathogens, C. neoformans initiates infection in the lungs. However, the main driver of mortality is invasive cryptococcosis leading to fungal meningitis. After C. neoformans gains a foothold in the lungs, a critical early step in invasion is transversal of the respiratory epithelium. In this review, we summarize current knowledge relating to pulmonary escape. We focus on fungal factors that allow C. neoformans to disseminate from the lungs via intracellular and extracellular routes.
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