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Menezes RT, Pereira TC, Junqueira JC, Oliveira LD, Scorzoni L. Synergistic combination of duloxetine hydrochloride and fluconazole reduces the cell growth and capsule size of Cryptococcus neoformans. AN ACAD BRAS CIENC 2022; 94:e20211021. [PMID: 35544847 DOI: 10.1590/0001-3765202220211021] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2021] [Accepted: 12/13/2021] [Indexed: 11/21/2022] Open
Abstract
This study aimed to evaluate the effect of duloxetine hydrochloride (DH) on Cryptococcus neoformans. DH minimum inhibitory concentration (MIC) and minimum fungicidal concentration (MFC) were 18.5 µg/mL, and the combination with fluconazole (FLZ) reduced the MIC value by 16-and 4-fold for DH and FLZ, respectively. The capsule size decreased by 67% and 16% when treated with DH and DH with FLZ, respectively. Therefore, this study showed that DH is active against C. neoformans alone and in combination with FLZ, leading to the reduction of the capsule size of this yeast.
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Affiliation(s)
- Raquel T Menezes
- Universidade Estadual Paulista (UNESP), Instituto de Ciência e Tecnologia, Departamento de Biociências e Diagnóstico Oral, Av. Engenheiro Francisco José Longo, 777, 12245-000 São José dos Campos, SP, Brazil
| | - Thaís C Pereira
- Universidade Estadual Paulista (UNESP), Instituto de Ciência e Tecnologia, Departamento de Biociências e Diagnóstico Oral, Av. Engenheiro Francisco José Longo, 777, 12245-000 São José dos Campos, SP, Brazil
| | - Juliana C Junqueira
- Universidade Estadual Paulista (UNESP), Instituto de Ciência e Tecnologia, Departamento de Biociências e Diagnóstico Oral, Av. Engenheiro Francisco José Longo, 777, 12245-000 São José dos Campos, SP, Brazil
| | - Luciane D Oliveira
- Universidade Estadual Paulista (UNESP), Instituto de Ciência e Tecnologia, Departamento de Biociências e Diagnóstico Oral, Av. Engenheiro Francisco José Longo, 777, 12245-000 São José dos Campos, SP, Brazil
| | - Liliana Scorzoni
- Universidade Estadual Paulista (UNESP), Instituto de Ciência e Tecnologia, Departamento de Biociências e Diagnóstico Oral, Av. Engenheiro Francisco José Longo, 777, 12245-000 São José dos Campos, SP, Brazil.,Pós-Graduação em Enfermagem, Universidade de Guarulhos (UNG), Rua Engenheiro Prestes Maia, 88, 07023-070 Guarulhos, SP, Brazil
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2
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Piffer AC, Santos FMD, Thomé MP, Diehl C, Garcia AWA, Kinskovski UP, Schneider RDO, Gerber A, Feltes BC, Schrank A, Vasconcelos ATR, Lenz G, Kmetzsch L, Vainstein MH, Staats CC. Transcriptomic analysis reveals that mTOR pathway can be modulated in macrophage cells by the presence of cryptococcal cells. Genet Mol Biol 2021; 44:e20200390. [PMID: 34352067 PMCID: PMC8341293 DOI: 10.1590/1678-4685-gmb-2020-0390] [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: 10/21/2020] [Accepted: 05/05/2021] [Indexed: 11/21/2022] Open
Abstract
Cryptococcus neoformans and Cryptococcus gattii are the etiological agents of cryptococcosis, a high mortality disease. The development of such disease depends on the interaction of fungal cells with macrophages, in which they can reside and replicate. In order to dissect the molecular mechanisms by which cryptococcal cells modulate the activity of macrophages, a genome-scale comparative analysis of transcriptional changes in macrophages exposed to Cryptococcus spp. was conducted. Altered expression of nearly 40 genes was detected in macrophages exposed to cryptococcal cells. The major processes were associated with the mTOR pathway, whose associated genes exhibited decreased expression in macrophages incubated with cryptococcal cells. Phosphorylation of p70S6K and GSK-3β was also decreased in macrophages incubated with fungal cells. In this way, Cryptococci presence could drive the modulation of mTOR pathway in macrophages possibly to increase the survival of the pathogen.
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Affiliation(s)
- Alícia C Piffer
- Universidade Federal do Rio Grande do Sul, Programa de Pós-Graduação em Biologia Celular e Molecular, Centro de Biotecnologia, Porto Alegre, RS, Brazil
| | - Francine M Dos Santos
- Universidade Federal do Rio Grande do Sul, Programa de Pós-Graduação em Biologia Celular e Molecular, Centro de Biotecnologia, Porto Alegre, RS, Brazil
| | - Marcos P Thomé
- Universidade Federal do Rio Grande do Sul, Programa de Pós-Graduação em Biologia Celular e Molecular, Centro de Biotecnologia, Porto Alegre, RS, Brazil
| | - Camila Diehl
- Universidade Federal do Rio Grande do Sul, Programa de Pós-Graduação em Biologia Celular e Molecular, Centro de Biotecnologia, Porto Alegre, RS, Brazil
| | - Ane Wichine Acosta Garcia
- Universidade Federal do Rio Grande do Sul, Programa de Pós-Graduação em Biologia Celular e Molecular, Centro de Biotecnologia, Porto Alegre, RS, Brazil
| | - Uriel Perin Kinskovski
- Universidade Federal do Rio Grande do Sul, Programa de Pós-Graduação em Biologia Celular e Molecular, Centro de Biotecnologia, Porto Alegre, RS, Brazil
| | - Rafael de Oliveira Schneider
- Universidade Federal do Rio Grande do Sul, Programa de Pós-Graduação em Biologia Celular e Molecular, Centro de Biotecnologia, Porto Alegre, RS, Brazil
| | - Alexandra Gerber
- Laboratório Nacional de Computação Científica, Petrópolis, RJ, Brazil
| | - Bruno César Feltes
- Universidade Federal do Rio Grande do Sul, Instituto de Informática, Porto Alegre, RS, Brazil
| | - Augusto Schrank
- Universidade Federal do Rio Grande do Sul, Programa de Pós-Graduação em Biologia Celular e Molecular, Centro de Biotecnologia, Porto Alegre, RS, Brazil
| | | | - Guido Lenz
- Universidade Federal do Rio Grande do Sul, Programa de Pós-Graduação em Biologia Celular e Molecular, Centro de Biotecnologia, Porto Alegre, RS, Brazil
| | - Lívia Kmetzsch
- Universidade Federal do Rio Grande do Sul, Programa de Pós-Graduação em Biologia Celular e Molecular, Centro de Biotecnologia, Porto Alegre, RS, Brazil
| | - Marilene H Vainstein
- Universidade Federal do Rio Grande do Sul, Programa de Pós-Graduação em Biologia Celular e Molecular, Centro de Biotecnologia, Porto Alegre, RS, Brazil
| | - Charley C Staats
- Universidade Federal do Rio Grande do Sul, Programa de Pós-Graduação em Biologia Celular e Molecular, Centro de Biotecnologia, Porto Alegre, RS, Brazil
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3
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Oliveira NK, Frank LA, Squizani ED, Reuwsaat JCV, Marques BM, Motta H, Garcia AWA, Kinskovski UP, Barcellos VA, Schrank A, Pohlmann AR, Staats CC, Guterres SS, Vainstein MH, Kmetzsch L. New nanotechnological formulation based on amiodarone-loaded lipid core nanocapsules displays anticryptococcal effect. Eur J Pharm Sci 2021; 162:105816. [PMID: 33757827 DOI: 10.1016/j.ejps.2021.105816] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2020] [Revised: 02/21/2021] [Accepted: 03/18/2021] [Indexed: 01/01/2023]
Abstract
Cryptococcus neoformans is the etiological agent of cryptococcal meningoencephalitis. The recommended available treatment has low efficiency, with high toxicity and resistance as recurrent problems. In the search of new treatment protocols, the proposal of new pharmacological approaches is considered an innovative strategy, mainly nanotechnological systems considering fungal diseases. The antiarrhythmic drug amiodarone has demonstrated antifungal activity against a range of fungi, including C. neoformans. Here, considering the importance of calcium storage mediated by transporters on cryptococcal virulence, we evaluated the use of the calcium channel blocker amiodarone as an alternative therapy for cryptococcosis. C. neoformans displayed high sensitivity to amiodarone, which was also synergistic with fluconazole. Amiodarone treatment influenced some virulence factors, interrupting the calcium-calcineurin signaling pathway. Experiments with murine cryptococcosis models revealed that amiodarone treatment increased the fungal burden in the lungs, while its combination with fluconazole did not improve treatment compared to fluconazole alone. In addition, we have developed different innovative nanotechnological formulations, one of which combining two drugs with different mechanisms of action. Lipid-core nanocapsules (LNC) loaded with amiodarone (LNCAMD), fluconazole (LNCFLU) and both (LNCAMD+FLU) were produced to achieve a better efficacy in vivo. In an intranasal model of treatment, all the LNC formulations had an antifungal effect. In an intraperitoneal treatment, LNCAMD showed an enhanced anticryptococcal effect compared to the free drug, whereas LNCFLU or LNCAMD+FLU displayed no differences from the free drugs. In this way, nanotechnology using amiodarone formulations could be an effective therapy for cryptococcal infections.
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Affiliation(s)
| | - Luiza Abrahão Frank
- Programa de Pós-Graduação em Ciências Farmacêuticas, Universidade Federal do Rio Grande do Sul, Porto Alegre RS, Brazil
| | - Eamim Daidrê Squizani
- Centro de Biotecnologia, Universidade Federal do Rio Grande do Sul, Porto Alegre, Brazil
| | | | | | - Heryk Motta
- Centro de Biotecnologia, Universidade Federal do Rio Grande do Sul, Porto Alegre, Brazil
| | | | - Uriel Perin Kinskovski
- Centro de Biotecnologia, Universidade Federal do Rio Grande do Sul, Porto Alegre, Brazil
| | | | - Augusto Schrank
- Centro de Biotecnologia, Universidade Federal do Rio Grande do Sul, Porto Alegre, Brazil; Departamento de Biologia Molecular e Biotecnologia, Universidade Federal do Rio Grande do Sul, Porto Alegre, Brazil
| | - Adriana Raffin Pohlmann
- Programa de Pós-Graduação em Ciências Farmacêuticas, Universidade Federal do Rio Grande do Sul, Porto Alegre RS, Brazil; Departamento de Química Orgânica, Instituto de Química, Universidade Federal do Rio Grande do Sul, Porto Alegre RS, Brazil
| | - Charley Christian Staats
- Centro de Biotecnologia, Universidade Federal do Rio Grande do Sul, Porto Alegre, Brazil; Departamento de Biologia Molecular e Biotecnologia, Universidade Federal do Rio Grande do Sul, Porto Alegre, Brazil
| | - Sílvia Stanisçuaski Guterres
- Programa de Pós-Graduação em Ciências Farmacêuticas, Universidade Federal do Rio Grande do Sul, Porto Alegre RS, Brazil
| | - Marilene Henning Vainstein
- Centro de Biotecnologia, Universidade Federal do Rio Grande do Sul, Porto Alegre, Brazil; Departamento de Biologia Molecular e Biotecnologia, Universidade Federal do Rio Grande do Sul, Porto Alegre, Brazil
| | - Lívia Kmetzsch
- Centro de Biotecnologia, Universidade Federal do Rio Grande do Sul, Porto Alegre, Brazil; Departamento de Biologia Molecular e Biotecnologia, Universidade Federal do Rio Grande do Sul, Porto Alegre, Brazil.
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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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Huang YM, Tao XH, Xu DF, Yu Y, Teng Y, Xie WQ, Fan YB. HOG1 has an essential role in the stress response, virulence and pathogenicity of Cryptococcus gattii. Exp Ther Med 2021; 21:476. [PMID: 33767771 PMCID: PMC7976431 DOI: 10.3892/etm.2021.9907] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2020] [Accepted: 02/05/2021] [Indexed: 12/25/2022] Open
Abstract
Cryptococcus gattii (C. gattii) is a lethal pathogen that causes the majority of cryptococcosis cases in previously healthy individuals. This pathogen poses an increasing threat to global public health, but the mechanisms underlying the pathogenesis have remained to be fully elucidated. In the present study, the role of high-osmolarity glycerol (HOG)1 in the stress reaction and virulence control of C. gattii was characterized by deleting the HOG1 gene using the clinical isolate strain CZ2012, and finally, the virulence and pathogenic traits of the deletion strain were defined. Deletion of the HOG1 gene resulted in notable growth defects under stress conditions (high salt and antifungal drugs), but different traits were observed under oxidative stress conditions (hydrogen peroxide). Similarly, the C. gattii hog1Δ strains (deletion of HOG1) also displayed decreased capsule production and melanin synthesis. Furthermore, mice infected with the hog1Δ strain had longer survival times than those infected with the wild-type strain and the reconstituted strain. The hog1Δ strain recovered from infected organs exhibited significant growth defects in terms of decreased colony count and size. The present results suggested that HOG1 has a significant role in the virulence of C. gattii and these results may help to elucidate the pathogenesis of C. gattii.
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Affiliation(s)
- You-Ming Huang
- Department of Dermatology, Zhejiang Provincial People's Hospital, People's Hospital of Hangzhou Medical College, Hangzhou, Zhejiang 310014, P.R. China
| | - Xiao-Hua Tao
- Department of Dermatology, Zhejiang Provincial People's Hospital, People's Hospital of Hangzhou Medical College, Hangzhou, Zhejiang 310014, P.R. China
| | - Dan-Feng Xu
- Department of Dermatology, Zhejiang Provincial People's Hospital, People's Hospital of Hangzhou Medical College, Hangzhou, Zhejiang 310014, P.R. China
| | - Yong Yu
- Department of Dermatology, Zhejiang Provincial People's Hospital, People's Hospital of Hangzhou Medical College, Hangzhou, Zhejiang 310014, P.R. China
| | - Yan Teng
- Department of Dermatology, Zhejiang Provincial People's Hospital, People's Hospital of Hangzhou Medical College, Hangzhou, Zhejiang 310014, P.R. China
| | - Wen-Qing Xie
- Department of Orthopedics, National Clinical Research Center for Geriatric Disorders, Xiangya Hospital, Central South University, Changsha, Hunan 410000, P.R. China
| | - Yi-Bin Fan
- Department of Dermatology, Zhejiang Provincial People's Hospital, People's Hospital of Hangzhou Medical College, Hangzhou, Zhejiang 310014, P.R. China
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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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7
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Woo YH, Martinez LR. Cryptococcus neoformans-astrocyte interactions: effect on fungal blood brain barrier disruption, brain invasion, and meningitis progression. Crit Rev Microbiol 2021; 47:206-223. [PMID: 33476528 DOI: 10.1080/1040841x.2020.1869178] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
Cryptococcus neoformans is an opportunistic, neurotropic, and encapsulated fungus that causes life-threatening cryptococcal meningitis (CM), especially in regions of the world where AIDS is endemic. The polysaccharide capsule of C. neoformans is the fungus major virulent factor, being copiously released during infection and causing immunosuppressive defects in the host. Although the capsular material is commonly associated with reactive astrocytes in fatal CM, little is known about the molecular and cellular interactions among astroglia and C. neoformans. As astrocytes also make up the neurovascular unit at the blood-brain barrier (BBB), which C. neoformans must transverse to colonize the central nervous system and cause CM; these cells may play a significant regulatory role in the prevention and progression of infection. For example, astrocytes are implicated in neurological disease including the regulation of cerebral intracranial pressure, immune function, and water homeostasis. Hence, in this review, we provide a general overview of astroglia biology and discuss the current knowledge on C. neoformans-astrocyte interactions including their involvement in the development of CM. This "gliocentric view" of cerebral cryptococcosis suggests that therapeutic interventions particularly targeting at preserving the neuroprotective function of astrocytes may be used in preventing and managing C. neoformans BBB transmigration, brain invasion, colonization, and meningitis.
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Affiliation(s)
- Yeon Hwa Woo
- Department of Metallurgical, Materials and Biomedical Engineering, College of Engineering, The University of Texas at El Paso, El Paso, TX, USA
| | - Luis R Martinez
- Department of Oral Biology, College of Dentistry, University of Florida, Gainesville, FL, USA
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Peng L, Yu Q, Zhu H, Zhu N, Zhang B, Wei H, Xu J, Li M. The V-ATPase regulates localization of the TRP Ca 2+ channel Yvc1 in response to oxidative stress in Candida albicans. Int J Med Microbiol 2020; 310:151466. [PMID: 33291030 DOI: 10.1016/j.ijmm.2020.151466] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2020] [Revised: 11/08/2020] [Accepted: 11/25/2020] [Indexed: 12/24/2022] Open
Abstract
The vacuolar-type H+-ATPase (V-ATPase) is a highly conserved protein complex among the eukaryotic cells. We previously revealed that both the V-ATPase and the transient receptor potential (TRP) channel Yvc1 are involved in oxidative stress response (OSR). However, the relationship between V-ATPase and Yvc1 during OSR remains unknown. In this study, disruption of the V-ATPase-encoding genes VPH2 and TFP1, similar with disruption of YVC1, caused H2O2 hypersensitivity and enhancement of vacuolar membrane permeability (VMP) under oxidative stress. Further investigations showed that unlike the wild type strain with vacuole membrane-localized Yvc1, both vph2Δ/Δ and tfp1Δ/Δ had Yvc1 localization in the vacuole cavity, indicating that disruption of VPH2 or TFP1 impaired normal vacuolar membrane-localization of Yvc1. Interestingly, addition of CaCl2 alleviated the growth defect of vph2Δ/Δ and tfp1Δ/Δ under oxidative stress, leading to prevention of VMP, decrease in ROS levels and activation of OSR. In contrast, addition of the Ca2+ chelating agent glycol-bis-(2-aminoethylether)-N,N,N',N'-tetraacetic acid (EGTA) aggravated H2O2 hypersensitivity of the mutants. These results showed that the V-ATPase plays an important role in maintenance of normal Yvc1 localization, which contributes to Ca2+ transport from the vacuoles to the cytosol for activation of OSR. This work sheds a novel light on the interaction between V-ATPase and Ca2+ transport for regulation of OSR in C. albicans.
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Affiliation(s)
- Liping Peng
- Key Laboratory of Molecular Microbiology and Technology, Ministry of Education, College of Life Sciences, Nankai University, Tianjin 300071, PR China
| | - Qilin Yu
- Key Laboratory of Molecular Microbiology and Technology, Ministry of Education, College of Life Sciences, Nankai University, Tianjin 300071, PR China
| | - Hangqi Zhu
- Key Laboratory of Molecular Microbiology and Technology, Ministry of Education, College of Life Sciences, Nankai University, Tianjin 300071, PR China
| | - Nali Zhu
- Key Laboratory of Molecular Microbiology and Technology, Ministry of Education, College of Life Sciences, Nankai University, Tianjin 300071, PR China
| | - Bing Zhang
- Key Laboratory of Molecular Microbiology and Technology, Ministry of Education, College of Life Sciences, Nankai University, Tianjin 300071, PR China
| | - Henan Wei
- Key Laboratory of Molecular Microbiology and Technology, Ministry of Education, College of Life Sciences, Nankai University, Tianjin 300071, PR China
| | - Jiachun Xu
- Key Laboratory of Molecular Microbiology and Technology, Ministry of Education, College of Life Sciences, Nankai University, Tianjin 300071, PR China
| | - Mingchun Li
- Key Laboratory of Molecular Microbiology and Technology, Ministry of Education, College of Life Sciences, Nankai University, Tianjin 300071, PR China.
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Yu CH, Chen Y, Desjardins CA, Tenor JL, Toffaletti DL, Giamberardino C, Litvintseva A, Perfect JR, Cuomo CA. Landscape of gene expression variation of natural isolates of Cryptococcus neoformans in response to biologically relevant stresses. Microb Genom 2020; 6. [PMID: 31860441 PMCID: PMC7067042 DOI: 10.1099/mgen.0.000319] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
Cryptococcus neoformans is an opportunistic fungal pathogen that at its peak epidemic levels caused an estimated million cases of cryptococcal meningitis per year worldwide. This species can grow in diverse environmental (trees, soil and bird excreta) and host niches (intracellular microenvironments of phagocytes and free-living in host tissues). The genetic basic for adaptation to these different conditions is not well characterized, as most experimental work has relied on a single reference strain of C. neoformans. To identify genes important for yeast infection and disease progression, we profiled the gene expression of seven C. neoformans isolates grown in five representative in vitro environmental and in vivo conditions. We characterized gene expression differences using RNA-Seq (RNA sequencing), comparing clinical and environmental isolates from two of the major lineages of this species, VNI and VNBI. These comparisons highlighted genes showing lineage-specific expression that are enriched in subtelomeric regions and in lineage-specific gene clusters. By contrast, we find few expression differences between clinical and environmental isolates from the same lineage. Gene expression specific to in vivo stages reflects available nutrients and stresses, with an increase in fungal metabolism within macrophages, and an induction of ribosomal and heat-shock gene expression within the subarachnoid space. This study provides the widest view to date of the transcriptome variation of C. neoformans across natural isolates, and provides insights into genes important for in vitro and in vivo growth stages.
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Affiliation(s)
- Chen-Hsin Yu
- Division of Infectious Diseases, Department of Medicine, Duke University School of Medicine, Durham, NC 27710, USA
| | - Yuan Chen
- Division of Infectious Diseases, Department of Medicine, Duke University School of Medicine, Durham, NC 27710, USA
| | | | - Jennifer L Tenor
- Division of Infectious Diseases, Department of Medicine, Duke University School of Medicine, Durham, NC 27710, USA
| | - Dena L Toffaletti
- Division of Infectious Diseases, Department of Medicine, Duke University School of Medicine, Durham, NC 27710, USA
| | - Charles Giamberardino
- Division of Infectious Diseases, Department of Medicine, Duke University School of Medicine, Durham, NC 27710, USA
| | - Anastasia Litvintseva
- Mycotic Diseases Branch, National Center for Emerging and Zoonotic Infectious Diseases, Centers for Disease Control and Prevention, Atlanta, GA 30329, USA
| | - John R Perfect
- Division of Infectious Diseases, Department of Medicine, Duke University School of Medicine, Durham, NC 27710, USA
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Insights into the Multi-Azole Resistance Profile in Candida haemulonii Species Complex. J Fungi (Basel) 2020; 6:jof6040215. [PMID: 33050545 PMCID: PMC7711680 DOI: 10.3390/jof6040215] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2020] [Revised: 10/06/2020] [Accepted: 10/08/2020] [Indexed: 12/25/2022] Open
Abstract
The Candida haemulonii complex (C. duobushaemulonii, C. haemulonii, and C. haemulonii var. vulnera) is composed of emerging, opportunistic human fungal pathogens able to cause invasive infections with high rates of clinical treatment failure. This fungal complex typically demonstrates resistance to first-line antifungals, including fluconazole. In the present work, we have investigated the azole resistance mechanisms expressed in Brazilian clinical isolates forming the C. haemulonii complex. Initially, 12 isolates were subjected to an antifungal susceptibility test, and azole cross-resistance was detected in almost all isolates (91.7%). In order to understand the azole resistance mechanistic basis, the efflux pump activity was assessed by rhodamine-6G. The C. haemulonii complex exhibited a significantly higher rhodamine-6G efflux than the other non-albicans Candida species tested (C. tropicalis, C. krusei, and C. lusitaneae). Notably, the efflux pump inhibitors (Phe-Arg and FK506) reversed the fluconazole and voricolazole resistance phenotypes in the C. haemulonii species complex. Expression analysis indicated that the efflux pump (ChCDR1, ChCDR2, and ChMDR1) and ERG11 genes were not modulated by either fluconazole or voriconazole treatments. Further, ERG11 gene sequencing revealed several mutations, some of which culminated in amino acid polymorphisms, as previously reported in azole-resistant Candida spp. Collectively, these data point out the relevance of drug efflux pumps in mediating azole resistance in the C. haemulonii complex, and mutations in ERG11p may contribute to this resistance profile.
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Squizani ED, Reuwsaat JCV, Lev S, Motta H, Sperotto J, Kaufman-Francis K, Desmarini D, Vainstein MH, Staats CC, Djordjevic JT, Kmetzsch L. Calcium Binding Protein Ncs1 Is Calcineurin Regulated in Cryptococcus neoformans and Essential for Cell Division and Virulence. mSphere 2020; 5:e00761-20. [PMID: 32907953 PMCID: PMC7485688 DOI: 10.1128/msphere.00761-20] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2020] [Accepted: 08/28/2020] [Indexed: 12/24/2022] Open
Abstract
Intracellular calcium (Ca2+) is crucial for signal transduction in Cryptococcus neoformans, the major cause of fatal fungal meningitis. The calcineurin pathway is the only Ca2+-requiring signaling cascade implicated in cryptococcal stress adaptation and virulence, with Ca2+ binding mediated by the EF-hand domains of the Ca2+ sensor protein calmodulin. In this study, we identified the cryptococcal ortholog of neuronal calcium sensor 1 (Ncs1) as a member of the EF-hand superfamily. We demonstrated that Ncs1 has a role in Ca2+ homeostasis under stress and nonstress conditions, as the ncs1Δ mutant is sensitive to a high Ca2+ concentration and has an elevated basal Ca2+ level. Furthermore, NCS1 expression is induced by Ca2+, with the Ncs1 protein adopting a punctate subcellular distribution. We also demonstrate that, in contrast to the case with Saccharomyces cerevisiae, NCS1 expression in C. neoformans is regulated by the calcineurin pathway via the transcription factor Crz1, as NCS1 expression is reduced by FK506 treatment and CRZ1 deletion. Moreover, the ncs1Δ mutant shares a high temperature and high Ca2+ sensitivity phenotype with the calcineurin and calmodulin mutants (cna1Δ and cam1Δ), and the NCS1 promoter contains two calcineurin/Crz1-dependent response elements (CDRE1). Ncs1 deficiency coincided with reduced growth, characterized by delayed bud emergence and aberrant cell division, and hypovirulence in a mouse infection model. In summary, our data show that Ncs1 has a significant role as a Ca2+ sensor in C. neoformans, working with calcineurin to regulate Ca2+ homeostasis and, consequently, promote fungal growth and virulence.IMPORTANCECryptococcus neoformans is the major cause of fungal meningitis in HIV-infected patients. Several studies have highlighted the important contributions of Ca2+ signaling and homeostasis to the virulence of C. neoformans Here, we identify the cryptococcal ortholog of neuronal calcium sensor 1 (Ncs1) and demonstrate its role in Ca2+ homeostasis, bud emergence, cell cycle progression, and virulence. We also show that Ncs1 function is regulated by the calcineurin/Crz1 signaling cascade. Our work provides evidence of a link between Ca2+ homeostasis and cell cycle progression in C. neoformans.
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Affiliation(s)
- Eamim Daidrê Squizani
- Centro de Biotecnologia, Universidade Federal do Rio Grande do Sul, UFRGS, Porto Alegre, Rio Grande do Sul, Brazil
| | | | - Sophie Lev
- Centre for Infectious Diseases and Microbiology, The Westmead Institute for Medical Research, Sydney, New South Wales, Australia
- Sydney Medical School-Westmead, University of Sydney, Sydney, New South Wales, Australia
- Marie Bashir Institute for Infectious Diseases and Biosecurity, University of Sydney, Sydney, New South Wales, Australia
| | - Heryk Motta
- Centro de Biotecnologia, Universidade Federal do Rio Grande do Sul, UFRGS, Porto Alegre, Rio Grande do Sul, Brazil
| | - Julia Sperotto
- Centro de Biotecnologia, Universidade Federal do Rio Grande do Sul, UFRGS, Porto Alegre, Rio Grande do Sul, Brazil
| | - Keren Kaufman-Francis
- Centre for Infectious Diseases and Microbiology, The Westmead Institute for Medical Research, Sydney, New South Wales, Australia
- Sydney Medical School-Westmead, University of Sydney, Sydney, New South Wales, Australia
- Marie Bashir Institute for Infectious Diseases and Biosecurity, University of Sydney, Sydney, New South Wales, Australia
| | - Desmarini Desmarini
- Centre for Infectious Diseases and Microbiology, The Westmead Institute for Medical Research, Sydney, New South Wales, Australia
- Sydney Medical School-Westmead, University of Sydney, Sydney, New South Wales, Australia
- Marie Bashir Institute for Infectious Diseases and Biosecurity, University of Sydney, Sydney, New South Wales, Australia
| | - Marilene Henning Vainstein
- Centro de Biotecnologia, Universidade Federal do Rio Grande do Sul, UFRGS, Porto Alegre, Rio Grande do Sul, Brazil
| | - Charley Christian Staats
- Centro de Biotecnologia, Universidade Federal do Rio Grande do Sul, UFRGS, Porto Alegre, Rio Grande do Sul, Brazil
| | - Julianne T Djordjevic
- Centre for Infectious Diseases and Microbiology, The Westmead Institute for Medical Research, Sydney, New South Wales, Australia
- Sydney Medical School-Westmead, University of Sydney, Sydney, New South Wales, Australia
- Marie Bashir Institute for Infectious Diseases and Biosecurity, University of Sydney, Sydney, New South Wales, Australia
| | - Lívia Kmetzsch
- Centro de Biotecnologia, Universidade Federal do Rio Grande do Sul, UFRGS, Porto Alegre, Rio Grande do Sul, Brazil
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12
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Garcia AWA, Kinskovski UP, Diehl C, Reuwsaat JCV, Motta de Souza H, Pinto HB, Trentin DDS, de Oliveira HC, Rodrigues ML, Becker EM, Kmetzsch L, Vainstein MH, Staats CC. Participation of Zip3, a ZIP domain-containing protein, in stress response and virulence in Cryptococcus gattii. Fungal Genet Biol 2020; 144:103438. [PMID: 32738289 DOI: 10.1016/j.fgb.2020.103438] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2019] [Revised: 07/21/2020] [Accepted: 07/22/2020] [Indexed: 12/16/2022]
Abstract
Cryptococcus gattii is an etiologic agent of cryptococcosis, a potentially fatal disease that affects humans and animals. The successful infection of mammalian hosts by cryptococcal cells relies on their ability to infect and survive in macrophages. Such phagocytic cells present a hostile environment to intracellular pathogens via the production of reactive nitrogen and oxygen species, as well as low pH and reduced nutrient bioavailability. To overcome the low-metal environment found during infection, fungal pathogens express high-affinity transporters, including members of the ZIP family. Previously, we determined that functional zinc uptake driven by Zip1 and Zip2 is necessary for full C.gattiivirulence. Here, we characterized the ZIP3 gene of C. gattii, an ortholog of the Saccharomyces cerevisiae ATX2, which codes a manganese transporter localized to the membrane of the Golgi apparatus. Cryptococcal cells lacking Zip3 were tolerant to toxic concentrations of manganese and had imbalanced expression of intracellular metal transporters, such as the vacuolar Pmc1 and Vcx1, as well as the Golgi Pmr1. Moreover, null mutants of the ZIP3 gene displayed higher sensitivity to reactive oxygen species (ROS) and substantial alteration in the expression of ROS-detoxifying enzyme-coding genes. In line with these phenotypes, cryptococcal cells displayed decreased virulence in a non-vertebrate model of cryptococcosis. Furthermore, we found that the ZIP3 null mutant strain displayed decreased melanization and secretion of the major capsular component glucuronoxylomannan, as well as an altered extracellular vesicle dimensions profile. Collectively, our data suggest that Zip3 activity impacts the physiology, and consequently, several virulence traits of C. gattii.
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Affiliation(s)
| | - Uriel Perin Kinskovski
- Centro de Biotecnologia, Universidade Federal do Rio Grande do Sul, Porto Alegre, Brazil
| | - Camila Diehl
- Centro de Biotecnologia, Universidade Federal do Rio Grande do Sul, Porto Alegre, Brazil
| | | | - Heryk Motta de Souza
- Centro de Biotecnologia, Universidade Federal do Rio Grande do Sul, Porto Alegre, Brazil
| | - Helber Barboza Pinto
- Departamento de Ciências Básicas da Saúde, Programa de Pós-Graduação em Biociências, Universidade Federal de Ciências da Saúde de Porto Alegre
| | - Danielle da Silva Trentin
- Departamento de Ciências Básicas da Saúde, Programa de Pós-Graduação em Biociências, Universidade Federal de Ciências da Saúde de Porto Alegre
| | | | - Marcio L Rodrigues
- Instituto Carlos Chagas, Fundação Oswaldo Cruz (Fiocruz), Curitiba, Brazil; Instituto de Microbiologia da Universidade Federal do Rio de Janeiro, Brazil
| | - Emilene Mendes Becker
- Instituto de Química, Universidade Federal do Rio Grande do Sul, Porto Alegre, Brazil
| | - Livia Kmetzsch
- Centro de Biotecnologia, Universidade Federal do Rio Grande do Sul, Porto Alegre, Brazil; Departamento de Biologia Molecular e Biotecnologia, Universidade Federal do Rio Grande do Sul, Porto Alegre, Brazil
| | - Marilene Henning Vainstein
- Centro de Biotecnologia, Universidade Federal do Rio Grande do Sul, Porto Alegre, Brazil; Departamento de Biologia Molecular e Biotecnologia, Universidade Federal do Rio Grande do Sul, Porto Alegre, Brazil
| | - Charley Christian Staats
- Centro de Biotecnologia, Universidade Federal do Rio Grande do Sul, Porto Alegre, Brazil; Departamento de Biologia Molecular e Biotecnologia, Universidade Federal do Rio Grande do Sul, Porto Alegre, Brazil.
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13
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Lange M, Peiter E. Calcium Transport Proteins in Fungi: The Phylogenetic Diversity of Their Relevance for Growth, Virulence, and Stress Resistance. Front Microbiol 2020; 10:3100. [PMID: 32047484 PMCID: PMC6997533 DOI: 10.3389/fmicb.2019.03100] [Citation(s) in RCA: 27] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2019] [Accepted: 12/20/2019] [Indexed: 12/26/2022] Open
Abstract
The key players of calcium (Ca2+) homeostasis and Ca2+ signal generation, which are Ca2+ channels, Ca2+/H+ antiporters, and Ca2+-ATPases, are present in all fungi. Their coordinated action maintains a low Ca2+ baseline, allows a fast increase in free Ca2+ concentration upon a stimulus, and terminates this Ca2+ elevation by an exponential decrease – hence forming a Ca2+ signal. In this respect, the Ca2+ signaling machinery is conserved in different fungi. However, does the similarity of the genetic inventory that shapes the Ca2+ peak imply that if “you’ve seen one, you’ve seen them all” in terms of physiological relevance? Individual studies have focused mostly on a single species, and mechanisms elucidated in few model organisms are usually extrapolated to other species. This mini-review focuses on the physiological relevance of the machinery that maintains Ca2+ homeostasis for growth, virulence, and stress responses. It reveals common and divergent functions of homologous proteins in different fungal species. In conclusion, for the physiological role of these Ca2+ transport proteins, “seen one,” in many cases, does not mean: “seen them all.”
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Affiliation(s)
- Mario Lange
- Plant Nutrition Laboratory, Institute of Agricultural and Nutritional Sciences, Faculty of Natural Sciences III, Martin Luther University of Halle-Wittenberg, Halle (Saale), Germany
| | - Edgar Peiter
- Plant Nutrition Laboratory, Institute of Agricultural and Nutritional Sciences, Faculty of Natural Sciences III, Martin Luther University of Halle-Wittenberg, Halle (Saale), Germany
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Wang Q, Fu C, Zhao Z, Fu A. Targeted Theranostic of Cryptococcal Encephalitis by a Novel Polypyridyl Ruthenium Complex. Mol Pharm 2019; 17:145-154. [PMID: 31800255 DOI: 10.1021/acs.molpharmaceut.9b00848] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Cryptococcus neoformans (C. neoformans) is one of the most well-known zoonotic fungal pathogens. Cryptococcal encephalitis remains a major cause of morbidity and mortality in immunocompromised hosts. Effective and targeting killing of C. neoformans in the brain is an essential approach to prevent and treat cryptococcal encephalitis. In this study, a fluorescent polypyridyl ruthenium complex RC-7, {[phen2Ru(bpy-dinonyl)](PF6)2 (phen = 1,10-phenanthroline, bpy-dinonyl = 4,4'-dinonyl-2,2'-bipyridine)}, was screened out, which showed a highly fungicidal effect on C. neoformans. The values of minimum inhibitory concentration (MIC) and minimum fungicidal concentration (MFC) in antifungal activities were significantly lower than fluconazole as the control. Moreover, RC-7 was prepared as a brain-targeting nanoliposome (RDP-liposome; RDP is a peptide derived from rabies virus glycoprotein) for in vivo application. The results revealed that the liposomes could accumulate in the encephalitis brain and play an antifungal role. Compared with the cryptococcal encephalitis model mice, the RDP-liposomes remarkably prolonged the survival days of the encephalitis-bearing mice from 10 days to 24 days. Here, we introduce a polypyridyl ruthenium complex that could be used as a novel antifungal agent, and this study may have a broad impact on the development of targeted delivery based on ruthenium complex-loaded liposomes for theranostics of cryptococcal encephalitis.
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Affiliation(s)
- Qinghua Wang
- College of Pharmaceutical Sciences , Southwest University , Chongqing 400715 , China.,College of Animal Science , Southwest University , Chongqing 402460 , China
| | - Chen Fu
- College of Pharmaceutical Sciences , Southwest University , Chongqing 400715 , China
| | - Zizhen Zhao
- College of Pharmaceutical Sciences , Southwest University , Chongqing 400715 , China
| | - Ailing Fu
- College of Pharmaceutical Sciences , Southwest University , Chongqing 400715 , China
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15
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Lev S, Li C, Desmarini D, Sorrell TC, Saiardi A, Djordjevic JT. Fungal Kinases With a Sweet Tooth: Pleiotropic Roles of Their Phosphorylated Inositol Sugar Products in the Pathogenicity of Cryptococcus neoformans Present Novel Drug Targeting Opportunities. Front Cell Infect Microbiol 2019; 9:248. [PMID: 31380293 PMCID: PMC6660261 DOI: 10.3389/fcimb.2019.00248] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2019] [Accepted: 06/26/2019] [Indexed: 12/17/2022] Open
Abstract
Invasive fungal pathogens cause more than 300 million serious human infections and 1.6 million deaths per year. A clearer understanding of the mechanisms by which these fungi cause disease is needed to identify novel targets for urgently needed therapies. Kinases are key components of the signaling and metabolic circuitry of eukaryotic cells, which include fungi, and kinase inhibition is currently being exploited for the treatment of human diseases. Inhibiting evolutionarily divergent kinases in fungal pathogens is a promising avenue for antifungal drug development. One such group of kinases is the phospholipase C1-dependent inositol polyphosphate kinases (IPKs), which act sequentially to transfer a phosphoryl group to a pre-phosphorylated inositol sugar (IP). This review focuses on the roles of fungal IPKs and their IP products in fungal pathogenicity, as determined predominantly from studies performed in the model fungal pathogen Cryptococcus neoformans, and compares them to what is known in non-pathogenic model fungi and mammalian cells to highlight potential drug targeting opportunities.
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Affiliation(s)
- Sophie Lev
- Centre for Infectious Diseases and Microbiology, The Westmead Institute for Medical Research, Sydney, NSW, Australia.,Sydney Medical School-Westmead, The University of Sydney, Sydney, NSW, Australia.,Marie Bashir Institute for Infectious Diseases and Biosecurity, University of Sydney, Sydney, NSW, Australia
| | - Cecilia Li
- Sydney Medical School-Westmead, The University of Sydney, Sydney, NSW, Australia.,Centre for Infectious Diseases and Microbiology-Public Health, NSW Health Pathology, Westmead Hospital, Sydney, NSW, Australia
| | - Desmarini Desmarini
- Centre for Infectious Diseases and Microbiology, The Westmead Institute for Medical Research, Sydney, NSW, Australia.,Sydney Medical School-Westmead, The University of Sydney, Sydney, NSW, Australia.,Marie Bashir Institute for Infectious Diseases and Biosecurity, University of Sydney, Sydney, NSW, Australia
| | - Tania C Sorrell
- Centre for Infectious Diseases and Microbiology, The Westmead Institute for Medical Research, Sydney, NSW, Australia.,Sydney Medical School-Westmead, The University of Sydney, Sydney, NSW, Australia.,Marie Bashir Institute for Infectious Diseases and Biosecurity, University of Sydney, Sydney, NSW, Australia
| | - Adolfo Saiardi
- MRC Laboratory for Molecular Cell Biology, University College London, London, United Kingdom
| | - Julianne T Djordjevic
- Centre for Infectious Diseases and Microbiology, The Westmead Institute for Medical Research, Sydney, NSW, Australia.,Sydney Medical School-Westmead, The University of Sydney, Sydney, NSW, Australia.,Marie Bashir Institute for Infectious Diseases and Biosecurity, University of Sydney, Sydney, NSW, Australia
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16
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Li Y, Zhang Y, Lu L. Calcium signaling pathway is involved in non-CYP51 azole resistance in Aspergillus fumigatus. Med Mycol 2019; 57:S233-S238. [PMID: 30816964 DOI: 10.1093/mmy/myy075] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2018] [Revised: 07/05/2018] [Accepted: 09/03/2018] [Indexed: 12/20/2022] Open
Abstract
The opportunistic fungal pathogen Aspergillus fumigatus, which is one of the primary airborne ascomycete pathogens and allergens worldwide, causes invasive fungal infections, which have high morbidity and mortality rates among immunosuppressed patients. The abuse of azole antifungals results in serious drug resistance in clinical therapy. Thus, a thorough understanding of the azole drug resistance mechanism and screening of antifungal agents with a novel mode of action and new drug targets are required to fight against drug resistance. Current studies suggest that there are three major azole resistance mechanisms in fungal pathogens, including changes of the drug target Cyp51, activation of drug efflux pumps and induction of cellular stress responses. Fungi must adapt to a variety of external environmental stressors to survive. These obstacles include stress to the plasma membrane after azole antifungal treatments, high temperature, pH variation, and oxidative stress. As a filamentous fungus, A. fumigatus has evolved numerous signal-transduction systems to sense and respond to azole stresses to survive and proliferate in harsh environmental conditions. Among these signal-transduction systems, the Ca2+ signaling pathway is one of the most important response systems, which has been verified to be involved in stress adaptation. In this review, we have summarized how the components of the calcium-signaling pathway and their interaction network are involved in azole stress response in A. fumigatus.
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Affiliation(s)
- Yeqi Li
- Jiangsu Key laboratory for Microbes and Functional Genomics, Jiangsu Engineering and Technology Research Center for Microbiology, College of Life Sciences, Nanjing Normal University, Nanjing, 210023, China
| | - Yuanwei Zhang
- Jiangsu Key laboratory for Microbes and Functional Genomics, Jiangsu Engineering and Technology Research Center for Microbiology, College of Life Sciences, Nanjing Normal University, Nanjing, 210023, China
| | - Ling Lu
- Jiangsu Key laboratory for Microbes and Functional Genomics, Jiangsu Engineering and Technology Research Center for Microbiology, College of Life Sciences, Nanjing Normal University, Nanjing, 210023, China
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17
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Abstract
Maintenance of Ca2+ homeostasis is important for fungal cells to respond to a multitude of stresses, as well as antifungal treatment, and for virulence in animal models. Here, we demonstrate that a P-type ATPase, Pmc1p, is required for Candida albicans to respond to a variety of stresses, affects azole susceptibility, and is required to sustain tissue invasive hyphal growth and to cause disease in a mouse model of disseminated infection. Defining the mechanisms responsible for maintaining proper Ca2+ homeostasis in this important human pathogen can ultimately provide opportunities to devise new chemotherapeutic interventions that dysregulate intracellular signaling and induce Ca2+ toxicity. Calcium is a critically important secondary messenger of intracellular signal transduction in eukaryotes but must be maintained at low levels in the cytoplasm of resting cells to avoid toxicity. This is achieved by several pumps that actively transport excess cytoplasmic Ca2+ out of the cell across the plasma membrane and into other intracellular compartments. In fungi, the vacuole serves as the major storage site for excess Ca2+, with two systems actively transporting cytoplasmic calcium ions into the vacuole. The H+/Ca2+ exchanger, Vcx1p, harnesses the proton-motive force across the vacuolar membrane (generated by the V-ATPase) to drive Ca2+ transport, while the P-type ATPase Pmc1p uses ATP hydrolysis to translocate Ca2+ into the vacuole. Ca2+-dependent signaling is required for the prevalent human fungal pathogen Candida albicans to endure exposure to the azole antifungals and to cause disease within the mammalian host. The purpose of this study was to determine if the Pmc1p or Vcx1p Ca2+ pumps are required for C. albicans pathogenicity and if these pumps impact antifungal resistance. Our results indicate that Pmc1p is required by C. albicans to transition from yeast to hyphal growth, to form biofilms in vitro, and to cause disease in a mouse model of disseminated infection. Moreover, loss of Pmc1p function appears to enhance C. albicans azole tolerance in a temperature-dependent manner. IMPORTANCE Maintenance of Ca2+ homeostasis is important for fungal cells to respond to a multitude of stresses, as well as antifungal treatment, and for virulence in animal models. Here, we demonstrate that a P-type ATPase, Pmc1p, is required for Candida albicans to respond to a variety of stresses, affects azole susceptibility, and is required to sustain tissue invasive hyphal growth and to cause disease in a mouse model of disseminated infection. Defining the mechanisms responsible for maintaining proper Ca2+ homeostasis in this important human pathogen can ultimately provide opportunities to devise new chemotherapeutic interventions that dysregulate intracellular signaling and induce Ca2+ toxicity.
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Dissecting the Roles of the Calcineurin Pathway in Unisexual Reproduction, Stress Responses, and Virulence in Cryptococcus deneoformans. Genetics 2017; 208:639-653. [PMID: 29233811 DOI: 10.1534/genetics.117.300422] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2017] [Accepted: 12/07/2017] [Indexed: 01/12/2023] Open
Abstract
The Ca2+/calmodulin-dependent protein phosphatase calcineurin orchestrates sexual reproduction, stress responses, and virulence via branched downstream pathways in the opportunistic human fungal pathogen Cryptococcus neoformans The calcineurin-binding protein Cbp1, the calcineurin temperature suppressor Cts1, the calcineurin-responsive zinc finger transcription factor Crz1, and the calcineurin targets Pbp1, Tif3, and Puf4, all function downstream of calcineurin to orchestrate distinct cellular processes. To elucidate how the calcineurin pathway regulatory network governs unisexual reproduction, stress responses, and virulence, we have analyzed the self-filamentous C. deneoformans strain, XL280α, and generated double mutants of these calcineurin downstream genes. We demonstrated that calcineurin governs unisexual reproduction at different sexual developmental stages, in which the initiation of the yeast-hyphal morphological transition is independent of Crz1, whereas the sporulation process is dependent on Crz1. Calcineurin-dependent unisexual reproduction is independent of the pheromone response pathway. Crz1 synergistically interacts with different calcineurin downstream targets in responding to ER, high-calcium, and cell wall stresses. We observed a widespread synergy suggesting that these proteins function in complex branched pathways downstream of calcineurin with some functional redundancy, which may allow efficient signaling network rewiring within the pathway for prompt adaptation to changing environments. Finally, we showed that deletion of PBP1 or TIF3 in the cna1∆ mutant background conferred a modest level of growth tolerance at 37°, but that the cna1∆ pbp1∆ and cna1∆ tif3∆ double mutants were both avirulent, suggesting that calcineurin may control virulence via mechanisms beyond thermotolerance.
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