1
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Zhang FY, Lian N, Li M. Macrophage pyroptosis induced by Candida albicans. Pathog Dis 2024; 82:ftae003. [PMID: 38499444 PMCID: PMC11162155 DOI: 10.1093/femspd/ftae003] [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: 07/02/2023] [Revised: 10/21/2023] [Accepted: 03/15/2024] [Indexed: 03/20/2024] Open
Abstract
Candida albicans (C. albicans) is a prevalent opportunistic pathogen that causes mucocutaneous and systemic infections, particularly in immunocompromised individuals. Macrophages play a crucial role in eliminating C. albicans in local and bloodstream contexts, while also regulating antifungal immune responses. However, C. albicans can induce macrophage lysis through pyroptosis, a type of regulated cell death. This process can enable C. albicans to escape from immune cells and trigger the release of IL-1β and IL-18, which can impact both the host and the pathogen. Nevertheless, the mechanisms by which C. albicans triggers pyroptosis in macrophages and the key factors involved in this process remain unclear. In this review, we will explore various factors that may influence or trigger pyroptosis in macrophages induced by C. albicans, such as hypha, ergosterol, cell wall remodeling, and other virulence factors. We will also examine the possible immune response following macrophage pyroptosis.
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Affiliation(s)
- Feng-yuan Zhang
- Hospital for Skin Diseases, Institute of Dermatology,Chinese Academy of Medical Sciences & Peking Union Medical College, 12th. JiangWangmiao street, Nanjing, 210042, China
| | - Ni Lian
- Hospital for Skin Diseases, Institute of Dermatology,Chinese Academy of Medical Sciences & Peking Union Medical College, 12th. JiangWangmiao street, Nanjing, 210042, China
| | - Min Li
- Hospital for Skin Diseases, Institute of Dermatology,Chinese Academy of Medical Sciences & Peking Union Medical College, 12th. JiangWangmiao street, Nanjing, 210042, China
- Center for Global Health, School of Public Health, Nanjing Medical University, 101st. LongMian Avenue, Nanjing, 211166, China
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2
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De Cesare GB, Hafez A, Stead D, Llorens C, Munro CA. Biomarkers of caspofungin resistance in Candida albicans isolates: A proteomic approach. Virulence 2022; 13:1005-1018. [PMID: 35730400 PMCID: PMC9225221 DOI: 10.1080/21505594.2022.2081291] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
Candida albicans is a clinically important polymorphic fungal pathogen that causes life-threatening invasive infections in immunocompromised patients. Antifungal therapy failure is a substantial clinical problem, due to the emergence of an increasing number of drug-resistant isolates. Caspofungin is a common antifungal drug, often used as first-line therapy that inhibits cell wall β-(1,3)-glucan synthesis. In this work, the cell surface of different echinocandin-resistant C. albicans clinical isolates was compared with sensitive isolates and their responses to echinocandin treatment analyzed. Proteomic analysis detected changes in the repertoire of proteins involved in cell wall organization and maintenance, in drug-resistant strains compared to susceptible isolates and after incubation with caspofungin. Moreover, an interaction network was created from the differential expression results. Our findings suggest drug resistance may involve not only a different cell wall architecture, but also a different response to drugs.
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Affiliation(s)
- Giuseppe Buda De Cesare
- School of Medicine, Medical Sciences and Nutrition, University of Aberdeen, Foresterhill, UK
| | - Ahmed Hafez
- Biotechvana, Parc Científic Universitat de València, Valencia, Spain.,Department of Experimental and Health Sciences, Universitat Pompeu Fabra, Barcelona, Spain.,Faculty of Computer and Information, Minia University, Minia, Egypt
| | - David Stead
- Aberdeen Proteomics, Rowett Institute ofNutrition and Health, University of Aberdeen, Foresterhill, UK
| | - Carlos Llorens
- Biotechvana, Parc Científic Universitat de València, Valencia, Spain
| | - Carol A Munro
- School of Medicine, Medical Sciences and Nutrition, University of Aberdeen, Foresterhill, UK
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3
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The Role of Sfp1 in Candida albicans Cell Wall Maintenance. J Fungi (Basel) 2022; 8:jof8111196. [PMID: 36422017 PMCID: PMC9692975 DOI: 10.3390/jof8111196] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2022] [Revised: 11/08/2022] [Accepted: 11/11/2022] [Indexed: 11/16/2022] Open
Abstract
The cell wall is the first interface for Candida albicans interaction with the surrounding environment and the host cells. Therefore, maintenance of cell wall integrity (CWI) is crucial for C. albicans survival and host-pathogen interaction. In response to environmental stresses, C. albicans undergoes cell wall remodeling controlled by multiple signaling pathways and transcription regulators. Here, we explored the role of the transcription factor Sfp1 in CWI. A deletion of the SFP1 gene not only caused changes in cell wall properties, cell wall composition and structure but also modulated expression of cell wall biosynthesis and remodeling genes. In addition, Cas5 is a known transcription regulator for C. albicans CWI and cell wall stress response. Interestingly, our results indicated that Sfp1 negatively controls the CAS5 gene expression by binding to its promoter element. Together, this study provides new insights into the regulation of C. albicans CWI and stress response.
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4
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Atanasova L, Moreno-Ruiz D, Grünwald-Gruber C, Hell V, Zeilinger S. The GPI-Anchored GH76 Protein Dfg5 Affects Hyphal Morphology and Osmoregulation in the Mycoparasite Trichoderma atroviride and Is Interconnected With MAPK Signaling. Front Microbiol 2021; 12:601113. [PMID: 33643233 PMCID: PMC7902864 DOI: 10.3389/fmicb.2021.601113] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2020] [Accepted: 01/05/2021] [Indexed: 11/13/2022] Open
Abstract
The fungal cell wall is composed of a cross-linked matrix of chitin, glucans, mannans, galactomannans, and cell wall proteins with mannan chains. Cell wall mannans are directly attached to the cell wall core, while the majority of mannoproteins is produced with a glycosylphosphatidylinositol (GPI) anchor and then transferred to β-1,6-glucan in the cell wall. In this study, we functionally characterized the transmembrane protein Dfg5 of the glycoside hydrolase family 76 (GH76) in the fungal mycoparasite Trichoderma atroviride, whose ortholog has recently been proposed to cross-link glycoproteins into the cell wall of yeast and fungi. We show that the T. atroviride Dfg5 candidate is a GPI-anchored, transmembrane, 6-hairpin member of the GH76 Dfg5 subfamily that plays an important role in hyphal morphology in this mycoparasite. Alterations in the release of proteins associated with cell wall remodeling as well as a higher amount of non-covalently bonded cell surface proteins were detected in the mutants compared to the wild-type. Gene expression analysis suggests that transcript levels of genes involved in glucan synthesis, of proteases involved in mycoparasitism, and of the Tmk1 mitogen-activated protein kinase (MAPK)-encoding gene are influenced by Dfg5, whereas Tmk3 governs Dfg5 transcription. We show that Dfg5 controls important physiological properties of T. atroviride, such as osmotic stress resistance, hyphal morphology, and cell wall stability.
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Affiliation(s)
- Lea Atanasova
- Department of Microbiology, University of Innsbruck, Innsbruck, Austria.,Department of Food Science and Technology, University of Natural Resources and Life Sciences, Vienna, Austria
| | | | - Clemens Grünwald-Gruber
- Division of Biochemistry, University of Natural Resources and Life Sciences, Vienna, Austria.,Core Facility Mass Spectrometry BOKU, University of Natural Resources and Life Sciences, Vienna, Austria
| | - Viktoria Hell
- Department of Food Science and Technology, University of Natural Resources and Life Sciences, Vienna, Austria
| | - Susanne Zeilinger
- Department of Microbiology, University of Innsbruck, Innsbruck, Austria
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5
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Wu C, Wu HT, Wang Q, Wang GH, Yi X, Chen YP, Zhou GX. Anticandidal Potential of Stem Bark Extract from Schima superba and the Identification of Its Major Anticandidal Compound. Molecules 2019; 24:E1587. [PMID: 31013655 PMCID: PMC6515076 DOI: 10.3390/molecules24081587] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2019] [Revised: 04/18/2019] [Accepted: 04/22/2019] [Indexed: 11/17/2022] Open
Abstract
Plant-derived extracts are a promising source of new drugs. Schima superba is traditionally used in China for heat clearing, detoxification, and treatment of furuncles. In this study, the anticandidal properties and mechanism of action of S. superba (SSE) were explored using a stem bark extract. SSE possessed high polyphenol and saponin contents of 256.6 ± 5.1 and 357.8 ± 31.5 µg/mg, respectively. A clear inhibition zone was observed for C. albicans growth through the disc diffusion method and the 50% inhibition of C. albicans by SSE was 415.2 µg/mL. Transcriptomic analysis in C. albicans treated with different doses of SSE was conducted through RNA-seq. Average values of 6068 genes and 20,842,500 clean reads were identified from each sample. Among these samples, 1680 and 1956 genes were differentially expressed genes (DEGs) from the SSE treatments of 0.2 and 0.4 mg/mL, respectively. C. albicans growth was inhibited by the changes in gene expression associated with the cell wall and membrane composition including the regulation of chitin degradation and ergosterol biosynthesis. This result could be reflected in the irregularly wrinkled morphology of the ruptured cell as revealed through SEM analysis. ESI-MS and NMR analyses revealed that the major compound purified from SSE was sasanquasaponin III and the 50% inhibition of C. albicans was 93.1 µg/mL. In summary, the traditional Chinese medicine S. superba can be applied as an anticandidal agent in complementary and alternative medicine.
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Affiliation(s)
- Chun Wu
- Xiamen Key Laboratory of Traditional Chinese Medicine Bio-engineering, Xiamen Medical College, Xiamen 361023, China.
- Key Laboratory of Functional and Clinical Translational Medicine, Fujian Province University, Xiamen Medical College, Xiamen 361023, China.
| | - Hong-Tan Wu
- Department of Medical Technology, Xiamen Medical College, Xiamen 361023, China.
- Application Technique Engineering Center of Natural Cosmeceuticals, College of Fujian Province, Xiamen Medical College, Xiamen 361023, China.
| | - Qing Wang
- Xiamen Key Laboratory of Traditional Chinese Medicine Bio-engineering, Xiamen Medical College, Xiamen 361023, China.
| | - Guey-Horng Wang
- Department of Medical Technology, Xiamen Medical College, Xiamen 361023, China.
- Application Technique Engineering Center of Natural Cosmeceuticals, College of Fujian Province, Xiamen Medical College, Xiamen 361023, China.
| | - Xue Yi
- Key Laboratory of Functional and Clinical Translational Medicine, Fujian Province University, Xiamen Medical College, Xiamen 361023, China.
| | - Yu-Pei Chen
- Department of Medical Technology, Xiamen Medical College, Xiamen 361023, China.
- Application Technique Engineering Center of Natural Cosmeceuticals, College of Fujian Province, Xiamen Medical College, Xiamen 361023, China.
| | - Guang-Xiong Zhou
- Guangdong Province Key Laboratory of Pharmacodynamic Constituents of TCM and New Drugs Research, College of Pharmacy, Jinan University, Guangzhou 510632, China.
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6
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Impact of Fungal MAPK Pathway Targets on the Cell Wall. J Fungi (Basel) 2018; 4:jof4030093. [PMID: 30096860 PMCID: PMC6162559 DOI: 10.3390/jof4030093] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2018] [Revised: 07/31/2018] [Accepted: 08/02/2018] [Indexed: 12/14/2022] Open
Abstract
The fungal cell wall is an extracellular organelle that provides structure and protection to cells. The cell wall also influences the interactions of cells with each other and surfaces. The cell wall can be reorganized in response to changing environmental conditions and different types of stress. Signaling pathways control the remodeling of the cell wall through target proteins that are in many cases not well defined. The Mitogen Activated Protein Kinase pathway that controls filamentous growth in yeast (fMAPK) was required for normal growth in media containing the cell wall perturbing agent Calcofluor White (CFW). A mass spectrometry (MASS-SPEC) approach and analysis of expression profiling data identified cell wall proteins and modifying enzymes whose levels were influenced by the fMAPK pathway. These include Flo11p, Flo10p, Tip1p, Pry2p and the mannosyltransferase, Och1p. Cells lacking Flo11p or Och1p were sensitive to CFW. The identification of cell wall proteins controlled by a MAPK pathway may provide insights into how signaling pathways regulate the cell wall.
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7
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Candida albicans Aro1 affects cell wall integrity, biofilm formation and virulence. JOURNAL OF MICROBIOLOGY, IMMUNOLOGY, AND INFECTION = WEI MIAN YU GAN RAN ZA ZHI 2018; 53:115-124. [PMID: 29807722 DOI: 10.1016/j.jmii.2018.04.002] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/01/2017] [Revised: 04/04/2018] [Accepted: 04/20/2018] [Indexed: 01/04/2023]
Abstract
BACKGROUND Candida albicans is an opportunistic pathogen capable of causing life-threatening systemic infections. The C. albicans ARO1 gene encodes an arom multifunctional enzyme, which can possibly catalyze reactions of the shikimate pathway to synthesize aromatic amino acids. However, the functions of C. albicans Aro1 have not been extensively characterized. METHODS ARO1 knockdown mutant strain was constructed, using a tetracycline-regulated (TR) expression system. Cell growth of the mutant strain was compared with wild type. Effects of the ARO1 gene knockdown on cell wall properties, adhesion to polystyrene and biofilm formation were further investigated. Finally, Galleria mellonella was used as a model host to study the role of ARO1 in virulence of C. albicans. RESULTS We showed that defective growth in the ARO1 knockdown strain was rescued by supplemental aromatic amino acids. In addition, the ARO1 knockdown strain was easily aggregated and precipitated. The knockdown of ARO1 also caused changes in cell wall properties and compositions and promoted C. albicans cell adhesion to polystyrene and biofilm formation. Finally, the ARO1 knockdown strain showed attenuation of C. albicans virulence. CONCLUSION This work provides new insights into C. albicans metabolism, cell wall and virulence.
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8
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Wang T, Xiu J, Zhang Y, Wu J, Ma X, Wang Y, Guo G, Shang X. Transcriptional Responses of Candida albicans to Antimicrobial Peptide MAF-1A. Front Microbiol 2017; 8:894. [PMID: 28567034 PMCID: PMC5434131 DOI: 10.3389/fmicb.2017.00894] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2017] [Accepted: 05/03/2017] [Indexed: 01/07/2023] Open
Abstract
Candida albicans is a major fungal pathogen in humans. Novel antifungal agents are urgent demanded due to the challenges of the resistance. Antimicrobial peptides (AMPs) are critical components of the innate immune system against pathogenic microorganism infection. MAF-1A is a novel cationic AMP that comes from Musca domestica and is effective against C. albicans, but the antifungal mechanism remains unclear. In this study, we performed a transcriptomics analysis in C. albicans using RNA-seq technique under the treatment of MAF-1A. A total of 5654 genes were identified. Among these, 1032 were differentially expressed genes (DEGs), including 575 up-regulated genes and 457 down-regulated genes. In these DEGs, genes encoding ergosterol metabolism and fatty acid biosynthesis were identified to be significantly down-regulated, while genes associated with oxidative stress response and cell wall were identified to be significantly up-regulated. Using pathway enrichment analysis, 12 significant metabolic pathways were identified, and ribosome, oxidative phosphorylation, citrate cycle were mainly involved. The results revealed that MAF-1A induces complex responses in C. albicans. This study provides evidence that MAF-1A may inhibit the growth through affect multi-targets in C. albicans cells.
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Affiliation(s)
- Tao Wang
- School of Basic Medical Sciences, Guizhou Medical UniversityGuiyang, China
| | - Jiangfan Xiu
- School of Basic Medical Sciences, Guizhou Medical UniversityGuiyang, China
| | - Yingchun Zhang
- School of Basic Medical Sciences, Guizhou Medical UniversityGuiyang, China
| | - Jianwei Wu
- School of Basic Medical Sciences, Guizhou Medical UniversityGuiyang, China
| | - Xiaolin Ma
- School of Basic Medical Sciences, Guizhou Medical UniversityGuiyang, China
| | - Yu Wang
- Guizhou Provincial Center for Disease Control and PreventionGuiyang, China
| | - Guo Guo
- School of Basic Medical Sciences, Guizhou Medical UniversityGuiyang, China
| | - Xiaoli Shang
- School of Biology and Engineering, Guizhou Medical UniversityGuiyang, China
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9
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Tong Y, Tang J. Candida albicans infection and intestinal immunity. Microbiol Res 2017; 198:27-35. [PMID: 28285659 DOI: 10.1016/j.micres.2017.02.002] [Citation(s) in RCA: 50] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2016] [Revised: 12/27/2016] [Accepted: 02/09/2017] [Indexed: 12/22/2022]
Abstract
Fungal infections cause high rates of morbidity and mortality in intensive care and immunocompromised patients, and can represent a life-threatening disease. As a microorganism commonly found in the intestine, Candida albicans (C. albicans) can invade the gut epithelium barrier via microfold cells and enter the bloodstream. The defensive potential of the intestinal barrier against invasive C. albicans is dependent on innate and adaptive immune responses which enable the host to eliminate pathogenic fungi. The lamina propria layer of the intestine contains numerous immune cells capable of inducing an innate cellular immune response against invasive fungi. This review focuses on the immune response triggered by a C. albicans infection in the intestine.
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Affiliation(s)
- Yiqing Tong
- Department of Trauma-Emergency & Critical Care Medicine, Shanghai Fifth People's Hospital, Fudan University; Shanghai 200240, PR China
| | - Jianguo Tang
- Department of Trauma-Emergency & Critical Care Medicine, Shanghai Fifth People's Hospital, Fudan University; Shanghai 200240, PR China.
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10
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Gabaldón T, Naranjo-Ortíz MA, Marcet-Houben M. Evolutionary genomics of yeast pathogens in the Saccharomycotina. FEMS Yeast Res 2016; 16:fow064. [PMID: 27493146 PMCID: PMC5815160 DOI: 10.1093/femsyr/fow064] [Citation(s) in RCA: 67] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Revised: 05/18/2016] [Accepted: 08/02/2016] [Indexed: 02/06/2023] Open
Abstract
Saccharomycotina comprises a diverse group of yeasts that includes numerous species of industrial or clinical relevance. Opportunistic pathogens within this clade are often assigned to the genus Candida but belong to phylogenetically distant lineages that also comprise non-pathogenic species. This indicates that the ability to infect humans has evolved independently several times among Saccharomycotina. Although the mechanisms of infection of the main groups of Candida pathogens are starting to be unveiled, we still lack sufficient understanding of the evolutionary paths that led to a virulent phenotype in each of the pathogenic lineages. Deciphering what genomic changes underlie the evolutionary emergence of a virulence trait will not only aid the discovery of novel virulence mechanisms but it will also provide valuable information to understand how new pathogens emerge, and what clades may pose a future danger. Here we review recent comparative genomics efforts that have revealed possible evolutionary paths to pathogenesis in different lineages, focusing on the main three agents of candidiasis worldwide: Candida albicans, C. parapsilosis and C. glabrata We will discuss what genomic traits may facilitate the emergence of virulence, and focus on two different genome evolution mechanisms able to generate drastic phenotypic changes and which have been associated to the emergence of virulence: gene family expansion and interspecies hybridization.
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Affiliation(s)
- Toni Gabaldón
- Department of Bioinformatics and Genomics, Centre for Genomic Regulation (CRG), The Barcelona Institute of Science and Technology, Dr. Aiguader 88, 08003 Barcelona, Spain Universitat Pompeu Fabra (UPF), 08003 Barcelona, Spain Institució Catalana de Recerca i Estudis Avançats (ICREA), Pg. Lluís Companys 23, 08010 Barcelona, Spain
| | - Miguel A Naranjo-Ortíz
- Department of Bioinformatics and Genomics, Centre for Genomic Regulation (CRG), The Barcelona Institute of Science and Technology, Dr. Aiguader 88, 08003 Barcelona, Spain Universitat Pompeu Fabra (UPF), 08003 Barcelona, Spain
| | - Marina Marcet-Houben
- Department of Bioinformatics and Genomics, Centre for Genomic Regulation (CRG), The Barcelona Institute of Science and Technology, Dr. Aiguader 88, 08003 Barcelona, Spain Universitat Pompeu Fabra (UPF), 08003 Barcelona, Spain
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11
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Louw M, du Toit M, Alexandre H, Divol B. Comparative morphological characteristics of three Brettanomyces bruxellensis wine strains in the presence/absence of sulfur dioxide. Int J Food Microbiol 2016; 238:79-88. [PMID: 27598001 DOI: 10.1016/j.ijfoodmicro.2016.08.040] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2016] [Revised: 08/08/2016] [Accepted: 08/29/2016] [Indexed: 12/26/2022]
Abstract
The red wine spoilage yeast Brettanomyces bruxellensis has been the subject of numerous investigations. Some of these studies focused on spoilage mechanisms, sulfur dioxide tolerance and nutrient requirements. Pseudomycelium formation, although a striking feature of this species, has however been poorly investigated. Furthermore, literature regarding the induction mechanism of pseudomycelium formation in this yeast is limited and lacks clarity, as results published are contradictory. This study elucidates this phenomenon among strains from geographically different areas. Potential environmental cues were investigated, to attain a better understanding of this mechanism and its role as a survival strategy. SO2 was previously reported to induce this morphological change however results obtained in this study did not support this. Nevertheless, the results obtained using scanning and transmission electron microscopy illustrate, for the first time in this yeast, deformity to the cell membrane and alterations to the fibrillar layers in SO2 treated cells. In addition, the SO2 exposed cultures displayed cell size variations, with cells displaying a decrease in length as well as delayed growth, with a prolonged lag phase. Fluorescence microscopy demonstrated a decrease in metabolic activity and the appearance of inclusion body-like structures in the cells following exposure to SO2.
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Affiliation(s)
- Marli Louw
- Institute for Wine Biotechnology, Department of Viticulture and Oenology, Stellenbosch University, Private Bag X1, Matieland, 7602, South Africa
| | - Maret du Toit
- Institute for Wine Biotechnology, Department of Viticulture and Oenology, Stellenbosch University, Private Bag X1, Matieland, 7602, South Africa
| | - Hervé Alexandre
- UMR PAM, Institut Universitaire de la Vigne et du Vin Jules Guyot, Université de Bourgogne, 21078 Dijon Cedex, France
| | - Benoit Divol
- Institute for Wine Biotechnology, Department of Viticulture and Oenology, Stellenbosch University, Private Bag X1, Matieland, 7602, South Africa.
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12
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Saraswat D, Kumar R, Pande T, Edgerton M, Cullen PJ. Signalling mucin Msb2 Regulates adaptation to thermal stress in Candida albicans. Mol Microbiol 2016; 100:425-41. [PMID: 26749104 PMCID: PMC4955288 DOI: 10.1111/mmi.13326] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 01/06/2016] [Indexed: 12/13/2022]
Abstract
Temperature is a potent inducer of fungal dimorphism. Multiple signalling pathways control the response to growth at high temperature, but the sensors that regulate these pathways are poorly defined. We show here that the signalling mucin Msb2 is a global regulator of temperature stress in the fungal pathogen Candida albicans. Msb2 was required for survival and hyphae formation at 42°C. The cytoplasmic signalling domain of Msb2 regulated temperature-dependent activation of the CEK mitogen activated proteins kinase (MAPK) pathway. The extracellular glycosylated domain of Msb2 (100-900 amino acid residues) had a new and unexpected role in regulating the protein kinase C (PKC) pathway. Msb2 also regulated temperature-dependent induction of genes encoding regulators and targets of the unfolded protein response (UPR), which is a protein quality control (QC) pathway in the endoplasmic reticulum that controls protein folding/degradation in response to high temperature and other stresses. The heat shock protein and cell wall component Ssa1 was also required for hyphae formation and survival at 42°C and regulated the CEK and PKC pathways.
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Affiliation(s)
- Darpan Saraswat
- Department of Oral Biology, University at Buffalo, Buffalo, NY, 14260-1300, USA
| | - Rohitashw Kumar
- Department of Oral Biology, University at Buffalo, Buffalo, NY, 14260-1300, USA
| | - Tanaya Pande
- Department of Biological Sciences, University at Buffalo, Buffalo, NY, 14260-1300, USA
| | - Mira Edgerton
- Department of Oral Biology, University at Buffalo, Buffalo, NY, 14260-1300, USA
| | - Paul J. Cullen
- Department of Biological Sciences, University at Buffalo, Buffalo, NY, 14260-1300, USA
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13
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Zheng NX, Wang Y, Hu DD, Yan L, Jiang YY. The role of pattern recognition receptors in the innate recognition of Candida albicans. Virulence 2016; 6:347-61. [PMID: 25714264 DOI: 10.1080/21505594.2015.1014270] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023] Open
Abstract
Candida albicans is both a commensal microorganism in healthy individuals and a major fungal pathogen causing high mortality in immunocompromised patients. Yeast-hypha morphological transition is a well known virulence trait of C. albicans. Host innate immunity to C. albicans critically requires pattern recognition receptors (PRRs). In this review, we summarize the PRRs involved in the recognition of C. albicans in epithelial cells, endothelial cells, and phagocytic cells separately. We figure out the differential recognition of yeasts and hyphae, the findings on PRR-deficient mice, and the discoveries on human PRR-related single nucleotide polymorphisms (SNPs).
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Affiliation(s)
- Nan-Xin Zheng
- a Changzheng Hospital ; Second Military Medical University ; Shanghai , China
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14
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Abstract
Morphogenesis in fungi is often induced by extracellular factors and executed by fungal genetic factors. Cell surface changes and alterations of the microenvironment often accompany morphogenetic changes in fungi. In this review, we will first discuss the general traits of yeast and hyphal morphotypes and how morphogenesis affects development and adaptation by fungi to their native niches, including host niches. Then we will focus on the molecular machinery responsible for the two most fundamental growth forms, yeast and hyphae. Last, we will describe how fungi incorporate exogenous environmental and host signals together with genetic factors to determine their morphotype and how morphogenesis, in turn, shapes the fungal microenvironment.
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Affiliation(s)
- Xiaorong Lin
- Department of Biology, Texas A&M University, College Station, Texas 77843-3258
| | - J Andrew Alspaugh
- Department of Medicine, Division of Infectious Diseases, Duke University Medical Center, Durham, North Carolina 27710
| | - Haoping Liu
- Department of Biological Chemistry, University of California, Irvine, California 92697
| | - Steven Harris
- Center for Plant Science Innovation, University of Nebraska-Lincoln, Lincoln, Nebraska 68588
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15
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Abstract
The human pathogenic fungus Candida albicans is the predominant cause of both superficial and invasive forms of candidiasis. C. albicans primarily infects immunocompromised individuals as a result of either immunodeficiency or intervention therapy, which highlights the importance of host immune defences in preventing fungal infections. The host defence system utilises a vast communication network of cells, proteins, and chemical signals distributed in blood and tissues, which constitute innate and adaptive immunity. Over the last decade the identity of many key molecules mediating host defence against C. albicans has been identified. This review will discuss how the host recognises this fungus, the events induced by fungal cells, and the host innate and adaptive immune defences that ultimately resolve C. albicans infections during health.
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16
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Tsai PW, Cheng YL, Hsieh WP, Lan CY. Responses of Candida albicans to the human antimicrobial peptide LL-37. J Microbiol 2014; 52:581-9. [PMID: 24879350 DOI: 10.1007/s12275-014-3630-2] [Citation(s) in RCA: 43] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2013] [Revised: 01/28/2014] [Accepted: 03/07/2014] [Indexed: 12/31/2022]
Abstract
Candida albicans is amajor fungal pathogen in humans. Antimicrobial peptides (AMPs) are critical components of the innate immune response in vertebrates and represent the first line of defense against microbial infection. LL-37 is the only member of the human family of cathelicidin AMPs and is commonly expressed by various tissues and cells, including surfaces of epithelia. The candidacidal effects of LL-37 have been well documented, but the mechanisms by which LL-37 kills C. albicans are not completely understood. In this study, we examined the effects of LL-37 on cell wall and cellular responses in C. albicans. Using transmission electron microscopy, carbohydrate analyses, and staining for β-1,3-glucan, changing of C. albicans cell wall integrity was detected upon LL-37 treatment. In addition, LL-37 also affected cell wall architecture of the pathogen. Finally, DNA microarray analysis and quantitative PCR demonstrated that sub-lethal concentrations of LL-37 modulated the expression of genes with a variety of functions, including transporters, regulators for biological processes, response to stress or chemical stimulus, and pathogenesis. Together, LL-37 induces complex responses in C. albicans, making LL-37 a promising candidate for use as a therapeutic agent against fungal infections.
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Affiliation(s)
- Pei-Wen Tsai
- Institute of Molecular and Cellular Biology, National Tsing Hua University, Hsinchu, 30013, Taiwan
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Distinct roles of Candida albicans-specific genes in host-pathogen interactions. EUKARYOTIC CELL 2014; 13:977-89. [PMID: 24610660 DOI: 10.1128/ec.00051-14] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
Human fungal pathogens are distributed throughout their kingdom, suggesting that pathogenic potential evolved independently. Candida albicans is the most virulent member of the CUG clade of yeasts and a common cause of both superficial and invasive infections. We therefore hypothesized that C. albicans possesses distinct pathogenicity mechanisms. In silico genome subtraction and comparative transcriptional analysis identified a total of 65 C. albicans-specific genes (ASGs) expressed during infection. Phenotypic characterization of six ASG-null mutants demonstrated that these genes are dispensable for in vitro growth but play defined roles in host-pathogen interactions. Based on these analyses, we investigated two ASGs in greater detail. An orf19.6688Δ mutant was found to be fully virulent in a mouse model of disseminated candidiasis and to induce higher levels of the proinflammatory cytokine interleukin-1β (IL-1β) following incubation with murine macrophages. A pga16Δ mutant, on the other hand, exhibited attenuated virulence. Moreover, we provide evidence that secondary filamentation events (multiple hyphae emerging from a mother cell and hyphal branching) contribute to pathogenicity: PGA16 deletion did not influence primary hypha formation or extension following contact with epithelial cells; however, multiple hyphae and hyphal branching were strongly reduced. Significantly, these hyphae failed to damage host cells as effectively as the multiple hypha structures formed by wild-type C. albicans cells. Together, our data show that species-specific genes of a eukaryotic pathogen can play important roles in pathogenicity.
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Caminero A, Calvo E, Valentín E, Ruiz-Herrera J, López JA, Sentandreu R. Identification of Candida albicans wall mannoproteins covalently linked by disulphide and/or alkali-sensitive bridges. Yeast 2014; 31:137-44. [PMID: 24519523 DOI: 10.1002/yea.3003] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2013] [Revised: 01/28/2014] [Accepted: 02/06/2014] [Indexed: 11/10/2022] Open
Abstract
This paper describes the results obtained by analysing the human pathogen Candida albicans cell wall subproteome by mass spectrometry, using extraction procedures aimed at releasing proteins bound by disulphide bridges (RAE-CWP) or alkali-labile ester linkages (ALS-CWP). Ten of the total proteins released from the wall by β-ME and/or NaOH contained a potential signal peptide, lacked a GPI cell wall hydrophobic C-terminal domain and were identified as true wall proteins by in silico analysis, whereas four additional proteins were identified as bound to the plasma membrane. The results surprisingly demonstrated that, in addition to the expected RAE-CWP and ALS-CWP proteins, 16 GPI proteins were bound to the wall by disulphide or alkali-sensitive bonds, since they were released by β-ME and/or NaOH. The biological significance of these results is discussed in relation to the added complexity of the organization of the proteins in the C. albicans cell wall.
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Affiliation(s)
- Antonio Caminero
- Departament de Microbiología i Ecología, Facultat de Farmacia, Universitat de València, Burjassot, Spain
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Identification of genes upregulated by the transcription factor Bcr1 that are involved in impermeability, impenetrability, and drug resistance of Candida albicans a/α biofilms. EUKARYOTIC CELL 2013; 12:875-88. [PMID: 23563485 DOI: 10.1128/ec.00071-13] [Citation(s) in RCA: 45] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
Candida albicans forms two types of biofilm, depending upon the configuration of the mating type locus. Although architecturally similar, a/α biofilms are impermeable, impenetrable, and drug resistant, whereas a/a and α/α biofilms lack these traits. The difference appears to be the result of an alternative matrix. Overexpression in a/a cells of BCR1, a master regulator of the a/α matrix, conferred impermeability, impenetrability, and drug resistance to a/a biofilms. Deletion of BCR1 in a/α cells resulted in the loss of these a/α-specific biofilm traits. Using BCR1 overexpression in a/a cells, we screened 107 genes of interest and identified 8 that were upregulated by Bcr1. When each was overexpressed in a/a biofilms, the three a/α traits were partially conferred, and when each was deleted in a/α cells, the traits were partially lost. Five of the eight genes have been implicated in iron homeostasis, and six encode proteins that are either in the wall or plasma membrane or secreted. All six possess sites for O-linked and N-linked glycosylation that, like glycosylphosphatidylinositol (GPI) anchors, can cross-link to the wall and matrix, suggesting that they may exert a structural role in conferring impermeability, impenetrability, and drug resistance, in addition to their physiological functions. The fact that in a screen of 107 genes, all 8 of the Bcr1-upregulated genes identified play a role in impermeability, impenetrability, and drug resistance suggests that the formation of the a/α matrix is highly complex and involves a larger number of genes than the initial ones identified here.
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Detection and characterization of megasatellites in orthologous and nonorthologous genes of 21 fungal genomes. EUKARYOTIC CELL 2013; 12:794-803. [PMID: 23543670 DOI: 10.1128/ec.00001-13] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Megasatellites are large DNA tandem repeats, originally described in Candida glabrata, in protein-coding genes. Most of the genes in which megasatellites are found are of unknown function. In this work, we extended the search for megasatellites to 20 additional completely sequenced fungal genomes and extracted 216 megasatellites in 203 out of 142,121 genes, corresponding to the most exhaustive description of such genetic elements available today. We show that half of the megasatellites detected encode threonine-rich peptides predicted to be intrinsically disordered, suggesting that they may interact with several partners or serve as flexible linkers. Megasatellite motifs were clustered into several families. Their distribution in fungal genes shows that different motifs are found in orthologous genes and similar motifs are found in unrelated genes, suggesting that megasatellite formation or spreading does not necessarily track the evolution of their host genes. Altogether, these results suggest that megasatellites are created and lost during evolution of fungal genomes, probably sharing similar functions, although their primary sequences are not necessarily conserved.
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Wagener J, Weindl G, de Groot PWJ, de Boer AD, Kaesler S, Thavaraj S, Bader O, Mailänder-Sanchez D, Borelli C, Weig M, Biedermann T, Naglik JR, Korting HC, Schaller M. Glycosylation of Candida albicans cell wall proteins is critical for induction of innate immune responses and apoptosis of epithelial cells. PLoS One 2012; 7:e50518. [PMID: 23226301 PMCID: PMC3511564 DOI: 10.1371/journal.pone.0050518] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2012] [Accepted: 10/23/2012] [Indexed: 12/20/2022] Open
Abstract
C. albicans is one of the most common fungal pathogen of humans, causing local and superficial mucosal infections in immunocompromised individuals. Given that the key structure mediating host-C. albicans interactions is the fungal cell wall, we aimed to identify features of the cell wall inducing epithelial responses and be associated with fungal pathogenesis. We demonstrate here the importance of cell wall protein glycosylation in epithelial immune activation with a predominant role for the highly branched N-glycosylation residues. Moreover, these glycan moieties induce growth arrest and apoptosis of epithelial cells. Using an in vitro model of oral candidosis we demonstrate, that apoptosis induction by C. albicans wild-type occurs in early stage of infection and strongly depends on intact cell wall protein glycosylation. These novel findings demonstrate that glycosylation of the C. albicans cell wall proteins appears essential for modulation of epithelial immunity and apoptosis induction, both of which may promote fungal pathogenesis in vivo.
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Affiliation(s)
- Jeanette Wagener
- Department of Dermatology, Eberhard Karls University Tübingen, Tübingen, Germany
- Aberdeen Fungal Group, Institute of Medical Sciences, University of Aberdeen, Aberdeen, United Kingdom
| | - Günther Weindl
- Department of Pharmacology and Toxicology, Institute of Pharmacy, Freie Universität Berlin, Berlin, Germany
| | - Piet W. J. de Groot
- Regional Center for Biomedical Research, Albacete Science & Technology Park, University of Castilla – La Mancha, Albacete, Spain
| | - Albert D. de Boer
- Regional Center for Biomedical Research, Albacete Science & Technology Park, University of Castilla – La Mancha, Albacete, Spain
- Department of Medical Microbiology and National Reference Center for Systemic Mycoses, University Medical Center Göttingen, Göttingen, Germany
| | - Susanne Kaesler
- Department of Dermatology, Eberhard Karls University Tübingen, Tübingen, Germany
| | - Selvam Thavaraj
- Department of Oral Immunology, King’s College London Dental Institute, King’s College London, London, United Kingdom
| | - Oliver Bader
- Department of Medical Microbiology and National Reference Center for Systemic Mycoses, University Medical Center Göttingen, Göttingen, Germany
| | | | - Claudia Borelli
- Department of Dermatology, Ludwig-Maximilians-University, München, Germany
| | - Michael Weig
- Department of Medical Microbiology and National Reference Center for Systemic Mycoses, University Medical Center Göttingen, Göttingen, Germany
| | - Tilo Biedermann
- Department of Dermatology, Eberhard Karls University Tübingen, Tübingen, Germany
| | - Julian R. Naglik
- Department of Oral Immunology, King’s College London Dental Institute, King’s College London, London, United Kingdom
| | | | - Martin Schaller
- Department of Dermatology, Eberhard Karls University Tübingen, Tübingen, Germany
- * E-mail:
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Valim CXR, Basso LR, dos Reis Almeida FB, Reis TF, Damásio ARL, Arruda LK, Martinez R, Roque-Barreira MC, Oliver C, Jamur MC, Coelho PSR. Characterization of PbPga1, an antigenic GPI-protein in the pathogenic fungus Paracoccidioides brasiliensis. PLoS One 2012; 7:e44792. [PMID: 23024763 PMCID: PMC3443090 DOI: 10.1371/journal.pone.0044792] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2012] [Accepted: 08/14/2012] [Indexed: 12/21/2022] Open
Abstract
Paracoccidioides brasiliensis is the etiologic agent of paracoccidioidomycosis (PCM), one of the most prevalent mycosis in Latin America. P. brasiliensis cell wall components interact with host cells and influence the pathogenesis of PCM. Cell wall components, such as glycosylphosphatidylinositol (GPI)-proteins play a critical role in cell adhesion and host tissue invasion. Although the importance of GPI-proteins in the pathogenesis of other medically important fungi is recognized, little is known about their function in P. brasiliensis cells and PCM pathogenesis. We cloned the PbPga1 gene that codifies for a predicted GPI-anchored glycoprotein from the dimorphic pathogenic fungus P. brasiliensis. PbPga1 is conserved in Eurotiomycetes fungi and encodes for a protein with potential glycosylation sites in a serine/threonine-rich region, a signal peptide and a putative glycosylphosphatidylinositol attachment signal sequence. Specific chicken anti-rPbPga1 antibody localized PbPga1 on the yeast cell surface at the septum between the mother cell and the bud with stronger staining of the bud. The exposure of murine peritoneal macrophages to rPbPga1 induces TNF-α release and nitric oxide (NO) production by macrophages. Furthermore, the presence of O-glycosylation sites was demonstrated by β-elimination under ammonium hydroxide treatment of rPbPga1. Finally, sera from PCM patients recognized rPbPga1 by Western blotting indicating the presence of specific antibodies against rPbPga1. In conclusion, our findings suggest that the PbPga1gene codifies for a cell surface glycoprotein, probably attached to a GPI-anchor, which may play a role in P. brasiliensis cell wall morphogenesis and infection. The induction of inflammatory mediators released by rPbPga1 and the reactivity of PCM patient sera toward rPbPga1 imply that the protein favors the innate mechanisms of defense and induces humoral immunity during P. brasiliensis infection.
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Affiliation(s)
- Clarissa X. R. Valim
- Departamento de Biologia Celular e Molecular e Biagentes Patogênicos, Faculdade de Medicina de Ribeirão Preto, São Paulo, Brazil
| | - Luiz Roberto Basso
- Departamento de Biologia Celular e Molecular e Biagentes Patogênicos, Faculdade de Medicina de Ribeirão Preto, São Paulo, Brazil
| | - Fausto B. dos Reis Almeida
- Departamento de Biologia Celular e Molecular e Biagentes Patogênicos, Faculdade de Medicina de Ribeirão Preto, São Paulo, Brazil
| | - Thaila Fernanda Reis
- Departamento de Biologia Celular e Molecular e Biagentes Patogênicos, Faculdade de Medicina de Ribeirão Preto, São Paulo, Brazil
| | | | - Luisa Karla Arruda
- Departamento de Clínica Médica, Faculdade de Medicina de Ribeirão Preto, São Paulo, Brazil
| | - Roberto Martinez
- Departamento de Clínica Médica, Faculdade de Medicina de Ribeirão Preto, São Paulo, Brazil
| | - Maria Cristina Roque-Barreira
- Departamento de Biologia Celular e Molecular e Biagentes Patogênicos, Faculdade de Medicina de Ribeirão Preto, São Paulo, Brazil
| | - Constance Oliver
- Departamento de Biologia Celular e Molecular e Biagentes Patogênicos, Faculdade de Medicina de Ribeirão Preto, São Paulo, Brazil
| | - Maria Célia Jamur
- Departamento de Biologia Celular e Molecular e Biagentes Patogênicos, Faculdade de Medicina de Ribeirão Preto, São Paulo, Brazil
| | - Paulo Sergio Rodrigues Coelho
- Departamento de Biologia Celular e Molecular e Biagentes Patogênicos, Faculdade de Medicina de Ribeirão Preto, São Paulo, Brazil
- * E-mail:
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23
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Abstract
Filamentous growth is a nutrient-regulated growth response that occurs in many fungal species. In pathogens, filamentous growth is critical for host-cell attachment, invasion into tissues, and virulence. The budding yeast Saccharomyces cerevisiae undergoes filamentous growth, which provides a genetically tractable system to study the molecular basis of the response. Filamentous growth is regulated by evolutionarily conserved signaling pathways. One of these pathways is a mitogen activated protein kinase (MAPK) pathway. A remarkable feature of the filamentous growth MAPK pathway is that it is composed of factors that also function in other pathways. An intriguing challenge therefore has been to understand how pathways that share components establish and maintain their identity. Other canonical signaling pathways-rat sarcoma/protein kinase A (RAS/PKA), sucrose nonfermentable (SNF), and target of rapamycin (TOR)-also regulate filamentous growth, which raises the question of how signals from multiple pathways become integrated into a coordinated response. Together, these pathways regulate cell differentiation to the filamentous type, which is characterized by changes in cell adhesion, cell polarity, and cell shape. How these changes are accomplished is also discussed. High-throughput genomics approaches have recently uncovered new connections to filamentous growth regulation. These connections suggest that filamentous growth is a more complex and globally regulated behavior than is currently appreciated, which may help to pave the way for future investigations into this eukaryotic cell differentiation behavior.
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Rodrigues ML. Surface architecture of fungal pathogens. Front Microbiol 2012; 3:80. [PMID: 22403580 PMCID: PMC3291873 DOI: 10.3389/fmicb.2012.00080] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2011] [Accepted: 02/16/2012] [Indexed: 01/15/2023] Open
Affiliation(s)
- Marcio L Rodrigues
- Laboratório de Estudos Integrados em Bioquímica Microbiana, Instituto de Microbiologia Professor Paulo de Góes, Universidade Federal do Rio de Janeiro Rio de Janeiro, Rio de Janeiro, Brazil
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25
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Ielasi FS, Decanniere K, Willaert RG. The epithelial adhesin 1 (Epa1p) from the human-pathogenic yeast Candida glabrata: structural and functional study of the carbohydrate-binding domain. ACTA CRYSTALLOGRAPHICA SECTION D: BIOLOGICAL CRYSTALLOGRAPHY 2012; 68:210-7. [PMID: 22349222 DOI: 10.1107/s0907444911054898] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/05/2011] [Accepted: 12/20/2011] [Indexed: 01/18/2023]
Abstract
The yeast Candida glabrata represents the second major cause of clinical candidiasis cases in the world. The ability of this opportunistic pathogen to adhere to human epithelial and endothelial cells relies on the Epa adhesins, a large set of cell-wall proteins whose N-terminal domains are endowed with a calcium-dependent lectin activity. This feature allows the yeast cells to adhere to host cells by establishing multiple interactions with the glycans expressed on their cell membrane. The ligand-binding domain of the Epa1p adhesin, which is one of the best characterized in the Epa family, was expressed in Escherichia coli, purified and crystallized in complex with lactose. Sequence identity with the domain of another yeast adhesin, the Flo5p flocculin from Saccharomyces cerevisiae, was exploited for molecular replacement and the structure of the domain was solved at a resolution of 1.65 Å. The protein is a member of the PA14 superfamily. It has a β-sandwich core and a DcisD calcium-binding motif, which is also present in the binding site of Flo5p. However, Epa1p differs from this homologue by the lack of a Flo5-like subdomain and by a significantly decreased accessibility of the solvent to the binding site, in which a calcium ion still plays an active role in the interactions with carbohydrates. This structural insight, together with fluorescence-assay data, confirms and explains the higher specificity of Epa1p adhesin for glycan molecules compared with the S. cerevisiae flocculins.
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Affiliation(s)
- Francesco S Ielasi
- Research Group Structural Biology Brussels (SBB), Department of Bioengineering Sciences, Vrije Universiteit Brussel, Pleinlaan 2, 1050 Brussels, Belgium
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26
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ProFASTA: A pipeline web server for fungal protein scanning with integration of cell surface prediction software. Fungal Genet Biol 2012; 49:173-9. [DOI: 10.1016/j.fgb.2011.12.009] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2011] [Revised: 12/21/2011] [Accepted: 12/22/2011] [Indexed: 11/19/2022]
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27
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Candida albicans morphogenesis and host defence: discriminating invasion from colonization. Nat Rev Microbiol 2011; 10:112-22. [PMID: 22158429 DOI: 10.1038/nrmicro2711] [Citation(s) in RCA: 583] [Impact Index Per Article: 44.8] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Candida albicans is a common fungal pathogen of humans that colonizes the skin and mucosal surfaces of most healthy individuals. Until recently, little was known about the mechanisms by which mucosal antifungal defences tolerate colonizing C. albicans but react strongly when hyphae of the same microorganism attempt to invade tissue. In this Review, we describe the properties of yeast cells and hyphae that are relevant to their interaction with the host, and the immunological mechanisms that differentially recognize colonizing versus invading C. albicans.
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28
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Tsai PW, Yang CY, Chang HT, Lan CY. Characterizing the role of cell-wall β-1,3-exoglucanase Xog1p in Candida albicans adhesion by the human antimicrobial peptide LL-37. PLoS One 2011; 6:e21394. [PMID: 21713010 PMCID: PMC3119699 DOI: 10.1371/journal.pone.0021394] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2011] [Accepted: 05/27/2011] [Indexed: 12/04/2022] Open
Abstract
Candida albicans is the major fungal pathogen of humans. Its adhesion to host-cell surfaces is the first critical step during mucosal infection. Antimicrobial peptides play important roles in the first line of mucosal immunity against C. albicans infection. LL-37 is the only member of the human cathelicidin antimicrobial peptide family and is commonly expressed in various tissues, including epithelium. We previously showed that LL-37 significantly reduced C. albicans adhesion to plastic, oral epidermoid OECM-1 cells, and urinary bladders of female BALB/c mice. The inhibitory effect of LL-37 on cell adhesion occurred via the binding of LL-37 to cell-wall carbohydrates. Here we showed that formation of LL-37–cell-wall protein complexes potentially inhibits C. albicans adhesion to polystyrene. Using phage display and ELISA, we identified 10 peptide sequences that could bind LL-37. A BLAST search revealed that four sequences in the major C. albicans cell-wall β-1,3-exoglucanase, Xog1p, were highly similar to the consensus sequence derived from the 10 biopanned peptides. One Xog1p-derived peptide, Xog1p90–115, and recombinant Xog1p associated with LL-37, thereby reversing the inhibitory effect of LL-37 on C. albicans adhesion. LL-37 reduced Xog1p activity and thus interrupted cell-wall remodeling. Moreover, deletion of XOG1 or another β-1,3-exoglucanase-encoding gene EXG2 showed that only when XOG1 was deleted did cellular exoglucanase activity, cell adhesion and LL-37 binding decrease. Antibodies against Xog1p also decreased cell adhesion. These data reveal that Xog1p, originally identified from LL-37 binding, has a role in C. albicans adhesion to polystyrene and, by inference, attach to host cells via direct or indirect manners. Compounds that target Xog1p might find use as drugs that prevent C. albicans infection. Additionally, LL-37 could potentially be used to screen for other cell-wall components involved in fungal cell adhesion.
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Affiliation(s)
- Pei-Wen Tsai
- Institute of Molecular and Cellular Biology, National Tsing Hua University, Hsinchu, Taiwan
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29
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Donohue DS, Ielasi FS, Goossens KVY, Willaert RG. The N-terminal part of Als1 protein from Candida albicans specifically binds fucose-containing glycans. Mol Microbiol 2011; 80:1667-79. [DOI: 10.1111/j.1365-2958.2011.07676.x] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
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30
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Dupres V, Dufrêne YF, Heinisch JJ. Measuring cell wall thickness in living yeast cells using single molecular rulers. ACS NANO 2010; 4:5498-504. [PMID: 20804167 DOI: 10.1021/nn101598v] [Citation(s) in RCA: 52] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/02/2023]
Abstract
Traditionally, the structural details of microbial cell walls are studied by thin-section electron microscopy, a technique that is very demanding and requires vacuum conditions, thus precluding live cell experiments. Here, we present a method integrating single-molecule atomic force microscopy (AFM) and protein design to measure cell wall thickness in a living yeast cell. The basic idea relies on the expression of His-tagged membrane sensors of increasing lengths in yeast and their subsequent specific detection at the cell surface using a modified AFM tip. After establishing the method on a wild-type strain, we demonstrate its potential by measuring changes in cell wall thickness within a few nanometers range, which result from (bio)chemical treatments or from mutations affecting the cell wall structure. The single molecular ruler method presented here not only avoids cell fixation artifacts but also provides new opportunities for studying the dynamics of microbial cell walls during growth, drug action, or enzymatic modification.
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Affiliation(s)
- Vincent Dupres
- Institute of Condensed Matter and Nanosciences, Université catholique de Louvain, Croix du Sud 2/18, B-1348 Louvain-la-Neuve, Belgium
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31
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Heinisch JJ, Dufrêne YF. Is there anyone out there?--Single-molecule atomic force microscopy meets yeast genetics to study sensor functions. Integr Biol (Camb) 2010; 2:408-15. [PMID: 20648385 DOI: 10.1039/c0ib00012d] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
The ability to react to environmental stress is a key feature of microbial cells, which frequently involves the fortification of their cell wall as a primary step. In the model yeast Saccharomyces cerevisiae the biosynthesis of the cell wall is regulated by the so-called cell wall integrity signal transduction pathway, which starts with the detection of cell surface stress by a small family of five membrane-spanning sensors (Wsc1-Wsc3, Mid2, Mtl1). Although genetic evidence indicated that these proteins act as mechanosensors, direct in vivo evidence for their function remained scarce. Here, we review a new approach integrating the tools and concepts of genetics with those of nanotechnology. We show how atomic force microscopy can be combined with advanced protein design by yeast genetics, to study the function and the mechanical properties of yeast sensors in living cells down to the single molecule level. We anticipate that this novel integrated technology will enable a paradigm shift in cell biology, so that pertinent questions can be addressed, such as the nanomechanics of single sensors and receptors, and how they distribute across the cell surface when they respond to extracellular stress.
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Affiliation(s)
- Jürgen J Heinisch
- Universität Osnabrück, Fachbereich Biologie/Chemie, AG Genetik, Osnabrück, Germany.
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32
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Frade-Pérez MD, Hernández-Cervantes A, Flores-Carreón A, Mora-Montes HM. Biochemical characterization of Candida albicans α-glucosidase I heterologously expressed in Escherichia coli. Antonie Van Leeuwenhoek 2010; 98:291-8. [DOI: 10.1007/s10482-010-9437-1] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2010] [Accepted: 03/23/2010] [Indexed: 11/30/2022]
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33
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Bromuro C, Romano M, Chiani P, Berti F, Tontini M, Proietti D, Mori E, Torosantucci A, Costantino P, Rappuoli R, Cassone A. Beta-glucan-CRM197 conjugates as candidates antifungal vaccines. Vaccine 2010; 28:2615-23. [DOI: 10.1016/j.vaccine.2010.01.012] [Citation(s) in RCA: 79] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2009] [Revised: 12/22/2009] [Accepted: 01/10/2010] [Indexed: 10/19/2022]
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34
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Mora-Montes HM, Ponce-Noyola P, Villagómez-Castro JC, Gow NA, Flores-Carreón A, López-Romero E. Protein glycosylation in Candida. Future Microbiol 2010; 4:1167-83. [PMID: 19895219 DOI: 10.2217/fmb.09.88] [Citation(s) in RCA: 66] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023] Open
Abstract
Candidiasis is a significant cause of invasive human mycosis with associated mortality rates that are equivalent to, or worse than, those cited for most cases of bacterial septicemia. As a result, considerable efforts are being made to understand how the fungus invades host cells and to identify new targets for fungal chemotherapy. This has led to an increasing interest in Candida glycobiology, with an emphasis on the identification of enzymes essential for glycoprotein and adhesion metabolism, and the role of N- and O-linked glycans in host recognition and virulence. Here, we refer to studies dealing with the identification and characterization of enzymes such as dolichol phosphate mannose synthase, dolichol phosphate glucose synthase and processing glycosidases and synthesis, structure and recognition of mannans and discuss recent findings in the context of Candida albicans pathogenesis.
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Hgc1 mediates dynamic Candida albicans-endothelium adhesion events during circulation. EUKARYOTIC CELL 2009; 9:278-87. [PMID: 20023069 DOI: 10.1128/ec.00307-09] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Common iatrogenic procedures can result in translocation of the human pathogenic fungus Candida albicans from mucosal surfaces to the bloodstream. Subsequent disseminated candidiasis and infection of deep-seated organs may occur if the fungus is not eliminated by blood cells. In these cases, fungal cells adhere to the endothelial cells of blood vessels, penetrate through endothelial layers, and invade deeper tissue. In this scenario, endothelial adhesion events must occur during circulation under conditions of physiological blood pressure. To investigate the fungal and host factors which contribute to this essential step of disseminated candidiasis, we have developed an in vitro circulatory C. albicans-endothelium interaction model. We demonstrate that both C. albicans yeast and hyphae can adhere under flow at a pressure similar to capillary blood pressure. Serum factors significantly enhanced the adhesion potential of viable but not killed C. albicans cells to endothelial cells. During circulation, C. albicans cells produced hyphae and the adhesion potential first increased, then decreased with time. We provide evidence that a specific temporal event in the yeast-to-hyphal transition, regulated by the G(1) cyclin Hgc1, is critical for C. albicans-endothelium adhesion during circulation.
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Young M, Macias S, Thomas D, Wormley FL. A proteomic-based approach for the identification of immunodominant Cryptococcus neoformans proteins. Proteomics 2009; 9:2578-88. [PMID: 19343717 DOI: 10.1002/pmic.200800713] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Cryptococcus neoformans is an opportunistic fungal pathogen that can cause life-threatening meningoencephalitis in immune compromised patients. Previous, studies in our laboratory have shown that prior exposure to an IFN-gamma-producing C. neoformans strain (H99gamma) elicits protective immunity against a second pulmonary C. neoformans challenge. Here, we characterized the antibody response produced in mice protected against experimental pulmonary C. neoformans infection compared to nonprotected mice. Moreover, we evaluated the efficacy of using serum antibody from protected mice to detect immunodominant C. neoformans proteins. Protected mice were shown to produce significantly more C. neoformans-specific antibodies following a second experimental pulmonary cryptococcal challenge compared to nonprotected mice. Immunoblot analysis of C. neoformans proteins resolved by 2-DE using serum from nonprotected mice failed to show any reactivity. In contrast, serum from protected mice was reactive with several cryptococcal protein spots. Analysis of these spots by capillary HPLC-ESI-MS/MS identified several cryptococcal proteins shown to be associated with the pathogenesis of cryptococcosis. Our studies demonstrate that mice immunized with C. neoformans strain H99gamma produce antibodies that are immune reactive against specific cryptococcal proteins that may provide a basis for the development of immune based therapies that induce protective anticryptococcal immune responses.
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Affiliation(s)
- Mattie Young
- Department of Biology, The University of Texas at San Antonio, San Antonio, TX 78249-0062, USA
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Biology and genetics of the pathogenic yeast Candida parapsilosis. Curr Genet 2009; 55:497-509. [DOI: 10.1007/s00294-009-0268-4] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2009] [Revised: 07/22/2009] [Accepted: 07/23/2009] [Indexed: 10/20/2022]
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Klis FM, Sosinska GJ, de Groot PWJ, Brul S. Covalently linked cell wall proteins of Candida albicans and their role in fitness and virulence. FEMS Yeast Res 2009; 9:1013-28. [PMID: 19624749 DOI: 10.1111/j.1567-1364.2009.00541.x] [Citation(s) in RCA: 120] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023] Open
Abstract
The cell wall of Candida albicans consists of an internal skeletal layer and an external protein coat. This coat has a mosaic-like nature, containing c. 20 different protein species covalently linked to the skeletal layer. Most of them are GPI proteins. Coat proteins vary widely in function. Many of them are involved in the primary interactions between C. albicans and the host and mediate adhesive steps or invasion of host cells. Others are involved in biofilm formation and cell-cell aggregation. They further include iron acquisition proteins, superoxide dismutases, and yapsin-like aspartic proteases. In addition, several covalently linked carbohydrate-active enzymes are present, whose precise functions remain hitherto largely elusive. The expression levels of the genes that encode covalently linked cell wall proteins (CWPs) can vary enormously. They depend on the mode of growth and the combined inputs of several signaling pathways that sense environmental conditions. This is reflected in the unusually long intergenic regions of most of these genes. Finally, the precise location of several covalently linked CWPs is temporally and spatially regulated. We conclude that covalently linked CWPs of C. albicans play a crucial role in fitness and virulence and that their expression is tightly controlled.
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Affiliation(s)
- Frans M Klis
- Swammerdam Institute for Life Sciences, University of Amsterdam, 1018 WV Amsterdam, The Netherlands.
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Role of the cell wall integrity and filamentous growth mitogen-activated protein kinase pathways in cell wall remodeling during filamentous growth. EUKARYOTIC CELL 2009; 8:1118-33. [PMID: 19502582 DOI: 10.1128/ec.00006-09] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
Many fungal species including pathogens exhibit filamentous growth (FG) as a means of foraging for nutrients. Genetic screens were performed to identify genes required for FG in the budding yeast Saccharomyces cerevisiae. Genes encoding proteins with established functions in transcriptional activation (MCM1, MATalpha2, PHD1, MSN2, SIR4, and HMS2), cell wall integrity (MPT5, WSC2, and MID2), and cell polarity (BUD5) were identified as potential regulators of FG. The transcription factors MCM1 and MATalpha2 induced invasive growth by promoting diploid-specific bipolar budding in haploid cells. Components of the cell wall integrity pathway including the cell surface proteins Slg1p/Wsc1p, Wsc2p, Mid2p, and the mitogen-activated protein kinase (MAPK) Slt2p/Mpk1p contributed to multiple aspects of the FG response including cell elongation, cell-cell adherence, and agar invasion. Mid2p and Wsc2p stimulated the FG MAPK pathway through the signaling mucin Msb2p and components of the MAPK cascade. The FG pathway contributed to cell wall integrity in parallel with the cell wall integrity pathway and in opposition with the high osmolarity glycerol response pathway. Mass spectrometry approaches identified components of the filamentous cell wall including the mucin-like proteins Msb2p, Flo11p, and subtelomeric (silenced) mucin Flo10p. Secretion of Msb2p, which occurs as part of the maturation of the protein, was inhibited by the ss-1,3-glucan layer of the cell wall, which highlights a new regulatory aspect to cell wall remodeling in this organism. Disruption of ss-1,3-glucan linkages induced mucin shedding and resulted in defects in cell-cell adhesion and invasion of cells into the agar matrix.
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Current awareness on yeast. Yeast 2009. [DOI: 10.1002/yea.1618] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022] Open
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The cell wall of the human pathogen Candida glabrata: differential incorporation of novel adhesin-like wall proteins. EUKARYOTIC CELL 2008; 7:1951-64. [PMID: 18806209 DOI: 10.1128/ec.00284-08] [Citation(s) in RCA: 178] [Impact Index Per Article: 11.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
The cell wall of the human pathogen Candida glabrata governs initial host-pathogen interactions that underlie the establishment of fungal infections. With the aim of identifying species-specific features that may directly relate to its virulence, we have investigated the cell wall of C. glabrata using a multidisciplinary approach that combines microscopy imaging, biochemical studies, bioinformatics, and tandem mass spectrometry. Electron microscopy revealed a bilayered wall structure in which the outer layer is packed with mannoproteins. Biochemical studies showed that C. glabrata walls incorporate 50% more protein than Saccharomyces cerevisiae walls and, consistent with this, have a higher mannose/glucose ratio. Evidence is presented that C. glabrata walls contain glycosylphosphatidylinositol (GPI) proteins, covalently bound to the wall 1,6-beta-glucan, as well as proteins linked through a mild-alkali-sensitive linkage to 1,3-beta-glucan. A comprehensive genome-wide in silico inspection showed that in comparison to other fungi, C. glabrata contains an exceptionally large number, 67, of genes encoding adhesin-like GPI proteins. Phylogenetically these adhesin-like proteins form different clusters, one of which is the lectin-like EPA family. Mass spectrometric analysis identified 23 cell wall proteins, including 4 novel adhesin-like proteins, Awp1/2/3/4, and Epa6, which is involved in adherence to human epithelia and biofilm formation. Importantly, the presence of adhesin-like proteins in the wall depended on the growth stage and on the genetic background used, and this was reflected in alterations in adhesion capacity and cell surface hydrophobicity. We propose that the large repertoire of adhesin(-like) genes of C. glabrata contributes to its adaptability and virulence.
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