51
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Regulatory mechanisms controlling morphology and pathogenesis in Candida albicans. Curr Opin Microbiol 2019; 52:27-34. [PMID: 31129557 DOI: 10.1016/j.mib.2019.04.005] [Citation(s) in RCA: 33] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2019] [Revised: 04/08/2019] [Accepted: 04/17/2019] [Indexed: 12/12/2022]
Abstract
Candida albicans, a major human fungal pathogen, can cause a wide variety of both mucosal and systemic infections, particularly in immunocompromised individuals. Multiple lines of evidence suggest a strong association between virulence and the ability of C. albicans to undergo a reversible morphological transition from yeast to filamentous cells in response to host environmental cues. Most previous studies on mechanisms important for controlling the C. albicans morphological transition have focused on signaling pathways and sequence-specific transcription factors. However, in recent years a variety of novel mechanisms have been reported, including those involving global transcriptional regulation and translational control. A large-scale functional genomics screen has also revealed new roles in filamentation for certain key biosynthesis pathways. This review article will highlight several of these exciting recent discoveries and discuss how they are relevant to the development of novel antifungal strategies. Ultimately, components of mechanisms that control C. albicans morphogenesis and pathogenicity could potentially serve as viable antifungal targets.
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52
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Gong J, Huang Q, Liang W, Wei Y, Huang G. The general transcriptional repressor Tup1 governs filamentous development in Candida tropicalis. Acta Biochim Biophys Sin (Shanghai) 2019; 51:463-470. [PMID: 30968937 DOI: 10.1093/abbs/gmz023] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2018] [Revised: 02/15/2019] [Accepted: 02/24/2019] [Indexed: 12/29/2022] Open
Abstract
Filamentous development is associated with the ability to cause infections and colonize the host in pathogenic Candida species. Candida tropicalis is one of the major fungal pathogens of humans. The conserved transcriptional repressor Tup1 plays a critical role in the regulation of transcription and filamentation in yeast species. Despite its central role, the full coding sequence of TUP1 has not been found in the reported genome sequence of C. tropicalis to date. In this study, we report the identification of Tup1 and characterize its role in filamentous growth in C. tropicalis. As expected, C. tropicalis Tup1 exhibits general conserved features to the orthologs of other fungi in terms of its structure and function. Deletion of TUP1 in C. tropicalis leads to increased filamentation under several culture conditions. However, Tup1 indeed exhibits species-specific roles in the regulation of filamentous development in C. tropicalis. For example, unlike the tup1/tup1 mutant of Candida albicans, the tup1/tup1 mutant of C. tropicalis is able to exist in the yeast form at low temperatures or in the presence of N-acetylglucosamine (GlcNAc). Acidic pH conditions also favor the yeast form of the tup1/tup1 mutant of C. tropicalis. Quantitative real-time PCR (qRT-PCR) assays indicate that Tup1 may regulate filamentous development through the transcriptional control of key filamentation regulators in C. tropicalis, such as Ume6, Brg1, Wor1, Sfl2, Ahr1, and Zcf3. Taken together, our findings demonstrate both conserved and species-specific roles of Tup1 in the regulation of filamentation and provide novel insights into the biology of C. tropicalis.
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Affiliation(s)
- Jiao Gong
- State Key Laboratory of Mycology, Institute of Microbiology, Chinese Academy of Sciences, Beijing, China
- College of Life Science, University of Chinese Academy of Sciences, Beijing, China
| | - Qian Huang
- Dermatology Department, Affiliated Hospital of Guizhou Medical University, Guiyang, China
| | - Weihong Liang
- State Key Laboratory of Mycology, Institute of Microbiology, Chinese Academy of Sciences, Beijing, China
| | - Yujia Wei
- Dermatology Department, Affiliated Hospital of Guizhou Medical University, Guiyang, China
| | - Guanghua Huang
- State Key Laboratory of Mycology, Institute of Microbiology, Chinese Academy of Sciences, Beijing, China
- College of Life Science, University of Chinese Academy of Sciences, Beijing, China
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53
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Yan Y, Tan F, Miao H, Wang H, Cao Y. Effect of Shikonin Against Candida albicans Biofilms. Front Microbiol 2019; 10:1085. [PMID: 31156594 PMCID: PMC6527961 DOI: 10.3389/fmicb.2019.01085] [Citation(s) in RCA: 45] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2018] [Accepted: 04/30/2019] [Indexed: 11/13/2022] Open
Abstract
Candidiasis is often associated with the formation of biofilms. Candida albicans biofilms are inherently resistant to many clinical antifungal agents and have increasingly been found to be the sources of C. albicans infections. Novel antifungal agents against C. albicans biofilms are urgently needed. The aim of this study was to investigate the effect of shikonin (SK) against C. albicans biofilms and to clarify the underlying mechanisms. XTT reduction assay showed that SK could not only inhibit the formation of biofilms but also destroy the maintenance of mature biofilms. In a mouse vulvovaginal candidiasis (VVC) model, the fungal burden was remarkably reduced upon SK treatment. Further study showed that SK could inhibit hyphae formation and reduce cellular surface hydrophobicity (CSH). Real-time reverse transcription-PCR analysis revealed that several hypha- and adhesion-specific genes were differentially expressed in SK-treated biofilm, including the downregulation of ECE1, HWP1, EFG1, CPH1, RAS1, ALS1, ALS3, CSH1 and upregulation of TUP1, NRG1, BCR1. Moreover, SK induced the production of farnesol, a quorum sensing molecule, and exogenous addition of farnesol enhanced the antibiofilm activity of SK. Taken together, these results indicated that SK could be a favorable antifungal agent in the clinical management of C. albicans biofilms.
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Affiliation(s)
- Yu Yan
- Shanghai Skin Disease Hospital, Tongji University School of Medicine, Shanghai, China
| | - Fei Tan
- Shanghai Skin Disease Hospital, Tongji University School of Medicine, Shanghai, China
| | - Hao Miao
- Institute of Basic Medicine, Chengde Medical University, Chengde, China
| | - Hui Wang
- School of Pharmacy, Second Military Medical University, Shanghai, China
| | - YingYing Cao
- Shanghai Skin Disease Hospital, Tongji University School of Medicine, Shanghai, China
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54
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Maciel EI, Jiang C, Barghouth PG, Nobile CJ, Oviedo NJ. The planarian Schmidtea mediterranea is a new model to study host-pathogen interactions during fungal infections. DEVELOPMENTAL AND COMPARATIVE IMMUNOLOGY 2019; 93:18-27. [PMID: 30571995 PMCID: PMC6333478 DOI: 10.1016/j.dci.2018.12.005] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/21/2018] [Revised: 11/07/2018] [Accepted: 12/11/2018] [Indexed: 05/06/2023]
Abstract
Candida albicans is one of the most common fungal pathogens of humans. Currently, there are limitations in the evaluation of C. albicans infection in existing animal models, especially in terms of understanding the influence of specific infectious stages of the fungal pathogen on the host. We show that C. albicans infects, grows and invades tissues in the planarian flatworm Schmidtea mediterranea, and that the planarian responds to infection by activating components of the host innate immune system to clear and repair host tissues. We study different stages of C. albicans infection and demonstrate that planarian stem cells increase division in response to fungal infection, a process that is likely evolutionarily conserved in metazoans. Our results implicate MORN2 and TAK1/p38 signaling pathways as possible mediators of the host innate immune response to fungal infection. We propose the use of planarians as a model system to investigate host-pathogen interactions during fungal infections.
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Affiliation(s)
- Eli Isael Maciel
- Department of Molecular & Cell Biology, University of California, Merced, USA; Quantitative and Systems Biology Graduate Program, University of California, Merced, USA
| | - Cen Jiang
- Department of Molecular & Cell Biology, University of California, Merced, USA; Department of Laboratory Medicine, Ruijin Hospital, Shanghai Jiaotong University School of Medicine, Shanghai, China
| | - Paul G Barghouth
- Department of Molecular & Cell Biology, University of California, Merced, USA; Quantitative and Systems Biology Graduate Program, University of California, Merced, USA
| | - Clarissa J Nobile
- Department of Molecular & Cell Biology, University of California, Merced, USA; Health Sciences Research Institute, University of California, Merced, USA.
| | - Néstor J Oviedo
- Department of Molecular & Cell Biology, University of California, Merced, USA; Health Sciences Research Institute, University of California, Merced, USA.
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55
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Regulation of Candida albicans Hyphal Morphogenesis by Endogenous Signals. J Fungi (Basel) 2019; 5:jof5010021. [PMID: 30823468 PMCID: PMC6463138 DOI: 10.3390/jof5010021] [Citation(s) in RCA: 56] [Impact Index Per Article: 11.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2019] [Revised: 02/25/2019] [Accepted: 02/26/2019] [Indexed: 12/15/2022] Open
Abstract
Candida albicans is a human commensal fungus that is able to assume several morphologies, including yeast, hyphal, and pseudohyphal. Under a range of conditions, C. albicans performs a regulated switch to the filamentous morphology, characterized by the emergence of a germ tube from the yeast cell, followed by a mold-like growth of branching hyphae. This transition from yeast to hyphal growth has attracted particular attention, as it has been linked to the virulence of C. albicans as an opportunistic human pathogen. Signal transduction pathways that mediate the induction of the hyphal transcription program upon the imposition of external stimuli have been extensively investigated. However, the hyphal morphogenesis transcription program can also be induced by internal cellular signals, such as inhibition of cell cycle progression, and conversely, the inhibition of hyphal extension can repress hyphal-specific gene expression, suggesting that endogenous cellular signals are able to modulate hyphal gene expression as well. Here we review recent developments in the regulation of the hyphal morphogenesis of C. albicans, with emphasis on endogenous morphogenetic signals.
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56
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Jain BP. Genome Wide Analysis of WD40 Proteins in Saccharomyces cerevisiae and Their Orthologs in Candida albicans. Protein J 2019; 38:58-75. [PMID: 30511317 DOI: 10.1007/s10930-018-9804-8] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
The WD40 domain containing proteins are present in the lower organisms (Monera) to higher complex metazoans with involvement in diverse cellular processes. The WD40 repeats fold into β propeller structure due to which the proteins harbouring WD40 domains function as scaffold by offering platform for interactions, bring together diverse cellular proteins to form a single complex for mediating downstream effects. Multiple functions of WD40 domain containing proteins in lower eukaryote as in Fungi have been reported with involvement in vegetative and reproductive growth, virulence etc. In this article insilico analysis of the WDR proteins in the budding yeast Saccharomyces cerevisiae was performed. By WDSP software 83 proteins in S. cerevisiae were identified with at least one WD40 motif. WD40 proteins with 6 or more WD40 motifs were considered for further studies. The WD40 proteins in yeast which are involved in various biological processes show distribution on all chromosomes (16 chromosomes in yeast) except chromosome 1. Besides the WD40 domain some of these proteins also contain other protein domains which might be responsible for the diversity in the functions of WD40 proteins in the budding yeast. These proteins in budding yeast were analysed by DAVID and Blast2Go software for functional and domains categorization. Candida albicans, an opportunistic fungal pathogen also have orthologs of these WD40 proteins with possible similar functions. This is the first time genome wide analysis of WD40 proteins in lower eukaryote i.e. budding yeast. This data may be useful in further study of the functional diversity of yeast proteomes.
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Affiliation(s)
- Buddhi Prakash Jain
- Department of Zoology, School of Life Sciences, Mahatma Gandhi Central University, Bihar, Motihari, 845401, India.
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57
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Randhawa A, Kundu D, Sharma A, Prasad R, Mondal AK. Overexpression of the CORVET complex alleviates the fungicidal effects of fludioxonil on the yeast Saccharomyces cerevisiae expressing hybrid histidine kinase 3. J Biol Chem 2018; 294:461-475. [PMID: 30446623 DOI: 10.1074/jbc.ra118.004736] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2018] [Revised: 10/25/2018] [Indexed: 11/06/2022] Open
Abstract
The hybrid histidine kinase 3 (HHK3) is a highly conserved sensor kinase in fungi that regulates the downstream HOG/p38 mitogen-activated protein kinase (MAPK). In addition to its role in osmoadaptation, HHK3 is involved in hyphal morphogenesis, conidiation, virulence, and cellular adaptation to oxidative stress. However, the molecular mechanisms by which it controls these processes remain obscure. Moreover, HHK3 is a molecular target for antifungal agents such as fludioxonil, which thereby interferes with the HOG/p38 pathway, leading to the abnormal accumulation of glycerol and subsequent cell lysis. Here, we used a chemical genomics approach with the yeast Saccharomyces cerevisiae to better understand the fungicidal action of fludioxonil and the role of HHK3 in fungal growth and physiology. Our results indicated that the abnormal accumulation of glycerol is not the primary cause of fludioxonil toxicity. Fludioxonil appears to impair endosomal trafficking in the fungal cells. We found that the components of class C core vacuole/endosome tethering (CORVET) complex are essential for yeast viability in the presence of a subthreshold dose of fludioxonil and that their overexpression alleviates fludioxonil toxicity. We also noted that by impeding secretory vesicle trafficking, fludioxonil inhibits hyphal growth in the opportunistic fungal pathogen Candida albicans Our results suggest that HHK3 regulates fungal hyphal growth by affecting vesicle trafficking. Together, our results reveal an important role of CORVET complex in the fungicidal action of fludioxonil downstream of HHK3.
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Affiliation(s)
- Anmoldeep Randhawa
- From the Council of Scientific and Industrial Research (CSIR)-Institute of Microbial Technology, Sector 39A, Chandigarh 160036, India
| | - Debasree Kundu
- From the Council of Scientific and Industrial Research (CSIR)-Institute of Microbial Technology, Sector 39A, Chandigarh 160036, India.,School of Life Sciences, Jawaharlal Nehru University, New Delhi 110067, India, and
| | - Anupam Sharma
- From the Council of Scientific and Industrial Research (CSIR)-Institute of Microbial Technology, Sector 39A, Chandigarh 160036, India
| | - Rajendra Prasad
- Amity Institute of Integrative Sciences and Health, Amity University, Gurgaon 122413, India
| | - Alok K Mondal
- School of Life Sciences, Jawaharlal Nehru University, New Delhi 110067, India, and
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58
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Guinan J, Villa P, Thangamani S. Secondary bile acids inhibit Candida albicans growth and morphogenesis. Pathog Dis 2018; 76:4966985. [PMID: 29648597 DOI: 10.1093/femspd/fty038] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2018] [Accepted: 04/09/2018] [Indexed: 02/07/2023] Open
Abstract
Candida albicans is one of the most common causes of fungal infections in humans with a significant mortality rate. However, the factors involved in C. albicans gastrointestinal (GI) colonization remain unclear. We hypothesize that secondary bile acids have direct antifungal activity against C. albicans and may play a critical role in maintaining GI colonization resistance against C. albicans. In this study, we investigated the effect of secondary bile acids including lithocholic acid (LCA) and deoxycholic acid (DCA) on C. albicans growth and morphogenesis. Results indicate that LCA and DCA at in vivo cecal micelle concentrations inhibit C. albicans growth in vitro. Interestingly, LCA and DCA also significantly inhibited the germ tube, hyphae and biofilm formation in C. albicans. In addition, pre-treatment of C. albicans with LCA and DCA significantly reduced the percentage of C. albicans cells attached to a colon cancer cell line. Collectively, our results demonstrate that secondary bile acids play an important role in controlling the growth and morphological switching of C. albicans. Results from this study demonstrate that secondary bile acid possess direct antifungal activity against C. albicans, explaining a potential mechanism for gastrointestinal colonization resistance against C. albicans.
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Affiliation(s)
- Jack Guinan
- Department of Pathology and Population Medicine, College of Veterinary Medicine, Midwestern University, 19555 N. 59th Ave. Glendale, AZ 85308, USA
| | - Pedro Villa
- Masters in Biomedical Science Program, Midwestern University, 19555 N. 59th Ave. Glendale, AZ 85308, USA
| | - Shankar Thangamani
- Department of Pathology and Population Medicine, College of Veterinary Medicine, Midwestern University, 19555 N. 59th Ave. Glendale, AZ 85308, USA
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59
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Diverse roles of Tup1p and Cyc8p transcription regulators in the development of distinct types of yeast populations. Curr Genet 2018; 65:147-151. [PMID: 30191307 DOI: 10.1007/s00294-018-0883-z] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2018] [Revised: 08/31/2018] [Accepted: 08/31/2018] [Indexed: 02/03/2023]
Abstract
Yeasts create multicellular structures of varying complexity, such as more complex colonies and biofilms and less complex flocs, each of which develops via different mechanisms. Colony biofilms originate from one or more cells that, through growth and division, develop a complicated three-dimensional structure consisting of aerial parts, agar-embedded invasive parts and a central cavity, filled with extracellular matrix. In contrast, flocs arise relatively quickly by aggregation of planktonic cells growing in liquid cultures after they reach the appropriate growth phase and/or exhaust nutrients such as glucose. Creation of both types of structures is dependent on the presence of flocculins: Flo11p in the former case and Flo1p in the latter. We recently showed that formation of both types of structures by wild Saccharomyces cerevisiae strain BR-F is regulated via transcription regulators Tup1p and Cyc8p, but in a divergent manner. Biofilm formation is regulated by Cyc8p and Tup1p antagonistically: Cyc8p functions as a repressor of FLO11 gene expression and biofilm formation, whereas Tup1p counteracts the Cyc8p repressor function and positively regulates biofilm formation and Flo11p expression. In addition, Tup1p stabilizes Flo11p probably by repressing a gene coding for a cell wall or extracellular protease that is involved in Flo11p degradation. In contrast, formation of BR-F flocs is co-repressed by the Cyc8p-Tup1p complex. These findings point to different mechanisms involved in yeast multicellularity.
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60
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Mutlu N, Kumar A. Messengers for morphogenesis: inositol polyphosphate signaling and yeast pseudohyphal growth. Curr Genet 2018; 65:119-125. [PMID: 30101372 DOI: 10.1007/s00294-018-0874-0] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2018] [Revised: 08/06/2018] [Accepted: 08/07/2018] [Indexed: 12/20/2022]
Abstract
In response to various environmental stimuli and stressors, the budding yeast Saccharomyces cerevisiae can initiate a striking morphological transition from its classic growth mode as isolated single cells to a filamentous form in which elongated cells remain connected post-cytokinesis in multi-cellular pseudohyphae. The formation of pseudohyphal filaments is regulated through an expansive signaling network, encompassing well studied and highly conserved pathways enabling changes in cell polarity, budding, cytoskeletal organization, and cell adhesion; however, changes in metabolite levels underlying the pseudohyphal growth transition are less well understood. We have recently identified a function for second messenger inositol polyphosphates (InsPs) in regulating pseudohyphal growth. InsPs are formed through the cleavage of membrane-bound phosphatidylinositol 4,5-bisphosphate (PIP2), and these soluble compounds are now being appreciated as important regulators of diverse processes, from phosphate homeostasis to cell migration. We find that kinases in the InsP pathway are required for wild-type pseudohyphal growth, and that InsP species exhibit characteristic profiles under conditions promoting filamentation. Ratios of the doubly phosphorylated InsP7 isoforms 5PP-InsP5 to 1PP-InsP5 are elevated in mutants exhibiting exaggerated pseudohyphal growth. Interestingly, S. cerevisiae mutants deleted of the mitogen-activated protein kinases (MAPKs) Kss1p or Fus3p or the AMP-activated kinase (AMPK) family member Snf1p display mutant InsP profiles, suggesting that these signaling pathways may contribute to the regulatory mechanism controlling InsP levels. Consequently, analyses of yeast pseudohyphal growth may be informative in identifying mechanisms regulating InsPs, while indicating a new function for these conserved second messengers in modulating cell stress responses and morphogenesis.
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Affiliation(s)
- Nebibe Mutlu
- Department of Molecular, Cellular, and Developmental Biology, University of Michigan, Ann Arbor, MI, 48109, USA
| | - Anuj Kumar
- Department of Molecular, Cellular, and Developmental Biology, University of Michigan, Ann Arbor, MI, 48109, USA.
- Program in Cellular and Molecular Biology, University of Michigan, Ann Arbor, MI, 48109, USA.
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61
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Trunk K, Peltier J, Liu YC, Dill BD, Walker L, Gow NAR, Stark MJR, Quinn J, Strahl H, Trost M, Coulthurst SJ. The type VI secretion system deploys antifungal effectors against microbial competitors. Nat Microbiol 2018; 3:920-931. [PMID: 30038307 PMCID: PMC6071859 DOI: 10.1038/s41564-018-0191-x] [Citation(s) in RCA: 136] [Impact Index Per Article: 22.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2017] [Accepted: 06/07/2018] [Indexed: 12/28/2022]
Abstract
Interactions between bacterial and fungal cells shape many polymicrobial communities. Bacteria elaborate diverse strategies to interact and compete with other organisms, including the deployment of protein secretion systems. The type VI secretion system (T6SS) delivers toxic effector proteins into host eukaryotic cells and competitor bacterial cells, but, surprisingly, T6SS-delivered effectors targeting fungal cells have not been reported. Here we show that the 'antibacterial' T6SS of Serratia marcescens can act against fungal cells, including pathogenic Candida species, and identify the previously undescribed effector proteins responsible. These antifungal effectors, Tfe1 and Tfe2, have distinct impacts on the target cell, but both can ultimately cause fungal cell death. 'In competition' proteomics analysis revealed that T6SS-mediated delivery of Tfe2 disrupts nutrient uptake and amino acid metabolism in fungal cells, and leads to the induction of autophagy. Intoxication by Tfe1, in contrast, causes a loss of plasma membrane potential. Our findings extend the repertoire of the T6SS and suggest that antifungal T6SSs represent widespread and important determinants of the outcome of bacterial-fungal interactions.
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Affiliation(s)
- Katharina Trunk
- Division of Molecular Microbiology, School of Life Sciences, University of Dundee, Dundee, UK
| | - Julien Peltier
- MRC Protein Phosphorylation and Ubiquitylation Unit, School of Life Sciences, University of Dundee, Dundee, UK
- Institute for Cell and Molecular Biosciences, Newcastle University, Newcastle-upon-Tyne, UK
| | - Yi-Chia Liu
- Division of Molecular Microbiology, School of Life Sciences, University of Dundee, Dundee, UK
| | - Brian D Dill
- MRC Protein Phosphorylation and Ubiquitylation Unit, School of Life Sciences, University of Dundee, Dundee, UK
| | - Louise Walker
- Aberdeen Fungal Group, Institute of Medical Sciences, MRC Centre for Medical Mycology at the University of Aberdeen, Aberdeen, UK
| | - Neil A R Gow
- Aberdeen Fungal Group, Institute of Medical Sciences, MRC Centre for Medical Mycology at the University of Aberdeen, Aberdeen, UK
| | - Michael J R Stark
- Centre for Gene Regulation and Expression, School of Life Sciences, University of Dundee, Dundee, UK
| | - Janet Quinn
- Institute for Cell and Molecular Biosciences, Newcastle University, Newcastle-upon-Tyne, UK
| | - Henrik Strahl
- Centre for Bacterial Cell Biology, Newcastle University, Newcastle-upon-Tyne, UK
| | - Matthias Trost
- MRC Protein Phosphorylation and Ubiquitylation Unit, School of Life Sciences, University of Dundee, Dundee, UK.
- Institute for Cell and Molecular Biosciences, Newcastle University, Newcastle-upon-Tyne, UK.
| | - Sarah J Coulthurst
- Division of Molecular Microbiology, School of Life Sciences, University of Dundee, Dundee, UK.
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62
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Lin CJ, Chen YL. Conserved and Divergent Functions of the cAMP/PKA Signaling Pathway in Candida albicans and Candida tropicalis. J Fungi (Basel) 2018; 4:E68. [PMID: 29890663 PMCID: PMC6023519 DOI: 10.3390/jof4020068] [Citation(s) in RCA: 25] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2018] [Revised: 05/28/2018] [Accepted: 06/07/2018] [Indexed: 01/03/2023] Open
Abstract
Fungal species undergo many morphological transitions to adapt to changing environments, an important quality especially in fungal pathogens. For decades, Candida albicans has been one of the most prevalent human fungal pathogens, and recently, the prevalence of Candida tropicalis as a causative agent of candidiasis has increased. In C. albicans, the ability to switch between yeast and hyphal forms is thought to be a key virulence factor and is regulated by multiple signaling cascades—including the cyclic adenosine monophosphate/protein kinase A (cAMP/PKA), calcineurin, high-osmolarity glycerol (HOG), and mitogen-activated protein kinases (MAPK) signaling pathways—upon receiving environmental cues. The cAMP/PKA signaling pathway also triggers white-opaque switching in C. albicans. However, studies on C. tropicalis morphogenesis are limited. In this minireview, we discuss the regulation of the yeast-hypha transition, virulence, and white-opaque switching through the cAMP/PKA pathway in the closely related species C. albicans and C. tropicalis.
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Affiliation(s)
- Chi-Jan Lin
- Department of Plant Pathology and Microbiology, National Taiwan University, 10617 Taipei, Taiwan.
| | - Ying-Lien Chen
- Department of Plant Pathology and Microbiology, National Taiwan University, 10617 Taipei, Taiwan.
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63
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Román E, Huertas B, Prieto D, Díez-Orejas R, Pla J. TUP1-mediated filamentation in Candida albicans leads to inability to colonize the mouse gut. Future Microbiol 2018; 13:857-867. [PMID: 29877100 DOI: 10.2217/fmb-2018-0012] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023] Open
Abstract
AIM To investigate the role of Candida albicans TUP1-mediated filamentation in the colonization of the mice gut. MATERIALS & METHODS We used molecular genetics to generate a strain where filamentation is regulated by altering the expression of the TUP1 gene with tetracyclines. RESULTS The colonization rates reached with the TUP1REP-RFPREP strain were lower compared with wild-type strain and completely absent after induction of filamentation. No differences in the susceptibility to bile salts nor in the adhesion to the mouse intestine epithelium were observed. CONCLUSION Blockage of C. albicans in a filamentous form impedes gut cell colonization in the mouse.
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Affiliation(s)
- Elvira Román
- Departamento de Microbiología y Parasitología, Facultad de Farmacia, Universidad Complutense de Madrid, Plaza de Ramón y Cajal s/n, E-28040 Madrid, Spain
| | - Blanca Huertas
- Departamento de Microbiología y Parasitología, Facultad de Farmacia, Universidad Complutense de Madrid, Plaza de Ramón y Cajal s/n, E-28040 Madrid, Spain
| | - Daniel Prieto
- Departamento de Microbiología y Parasitología, Facultad de Farmacia, Universidad Complutense de Madrid, Plaza de Ramón y Cajal s/n, E-28040 Madrid, Spain
| | - Rosalía Díez-Orejas
- Departamento de Microbiología y Parasitología, Facultad de Farmacia, Universidad Complutense de Madrid, Plaza de Ramón y Cajal s/n, E-28040 Madrid, Spain
| | - Jesús Pla
- Departamento de Microbiología y Parasitología, Facultad de Farmacia, Universidad Complutense de Madrid, Plaza de Ramón y Cajal s/n, E-28040 Madrid, Spain
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64
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Ali A, Jadhav A, Jangid P, Patil R, Shelar A, Karuppayil SM. The human muscarinic acetylcholine receptor antagonist, Dicyclomine targets signal transduction genes and inhibits the virulence factors in the human pathogen, Candida albicans. J Antibiot (Tokyo) 2018; 71:456-466. [PMID: 29348527 DOI: 10.1038/s41429-017-0013-z] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2017] [Revised: 11/20/2017] [Accepted: 11/28/2017] [Indexed: 11/09/2022]
Abstract
Dicyclomine is a human muscarinic acetylcholine receptor antagonist used for the treatment of abdominal cramps. We are reporting here that dicyclomine can inhibit the in vitro growth and virulence factors of the human pathogen Candida albicans very effectively. Dicyclomine inhibited adhesion, early biofilm, mature biofilm, and planktonic growth. Yeast to hyphal form transition of C. albicans in various inducer media such as serum, proline, glucose, and N-acetylglucosamine was inhibited. Dicyclomine also could kill C. albicans cells within 15 min of exposure. Dicyclomine appears to inhibit the yeast to hyphal conversion by affecting signal transduction pathway. The expression of selected genes associated with yeast to hyphal form transition in serum in presence of dicyclomine was studied using real-time polymerase chain reaction (RtPCR). The RtPCR analysis showed that dicyclomine targets both cAMP pathway as well as MAPK cascade. Eight genes were upregulated. Out of these, three major upregulated genes were Bcy1, Tup1, and Mig1. Dicyclomine downregulated Ume6, Ece1, and Pde2 genes which are involved in cAMP signaling pathway and also downregulated the DNA binding protein gene, Rfg1. Dicyclomine significantly upregulated the master negative regulator of hyphal formation, Tup1. Based on this study we suggest that the muscarinic acetylcholine receptor antagonist, dicyclomine could be repositioned as a potential anti-Candida albicans as well as anti-virulence agent.
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Affiliation(s)
- Awad Ali
- School of Life Sciences (DST-FIST&UGC-SAP Sponsored), SR TM University (NAAC Accredited with "A" grade), Nanded,, 431606, Maharashtra, India
| | - Ashwini Jadhav
- School of Life Sciences (DST-FIST&UGC-SAP Sponsored), SR TM University (NAAC Accredited with "A" grade), Nanded,, 431606, Maharashtra, India
| | - Priyanka Jangid
- School of Life Sciences (DST-FIST&UGC-SAP Sponsored), SR TM University (NAAC Accredited with "A" grade), Nanded,, 431606, Maharashtra, India
| | - Rajendra Patil
- School of Life Sciences (DST-FIST&UGC-SAP Sponsored), SR TM University (NAAC Accredited with "A" grade), Nanded,, 431606, Maharashtra, India
| | - Amruta Shelar
- School of Life Sciences (DST-FIST&UGC-SAP Sponsored), SR TM University (NAAC Accredited with "A" grade), Nanded,, 431606, Maharashtra, India
| | - Sankunny Mohan Karuppayil
- School of Life Sciences (DST-FIST&UGC-SAP Sponsored), SR TM University (NAAC Accredited with "A" grade), Nanded,, 431606, Maharashtra, India.
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65
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Rai LS, Singha R, Brahma P, Sanyal K. Epigenetic determinants of phenotypic plasticity in Candida albicans. FUNGAL BIOL REV 2018. [DOI: 10.1016/j.fbr.2017.07.002] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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66
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Basso V, d'Enfert C, Znaidi S, Bachellier-Bassi S. From Genes to Networks: The Regulatory Circuitry Controlling Candida albicans Morphogenesis. Curr Top Microbiol Immunol 2018; 422:61-99. [PMID: 30368597 DOI: 10.1007/82_2018_144] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
Abstract
Candida albicans is a commensal yeast of most healthy individuals, but also one of the most prevalent human fungal pathogens. During adaptation to the mammalian host, C. albicans encounters different niches where it is exposed to several types of stress, including oxidative, nitrosative (e.g., immune system), osmotic (e.g., kidney and oral cavity) stresses and pH variation (e.g., gastrointestinal (GI) tract and vagina). C. albicans has developed the capacity to respond to the environmental changes by modifying its morphology, which comprises the yeast-to-hypha transition, white-opaque switching, and chlamydospore formation. The yeast-to-hypha transition has been very well characterized and was shown to be modulated by several external stimuli that mimic the host environment. For instance, temperature above 37 ℃, serum, alkaline pH, and CO2 concentration are all reported to enhance filamentation. The transition is characterized by the activation of an intricate regulatory network of signaling pathways, involving many transcription factors. The regulatory pathways that control either the stress response or morphogenesis are required for full virulence and promote survival of C. albicans in the host. Many of these transcriptional circuitries have been characterized, highlighting the complexity and the interconnections between the different pathways. Here, we present the major signaling pathways and the main transcription factors involved in the yeast-to-hypha transition. Furthermore, we describe the role of heat shock transcription factors in the morphogenetic transition, providing an edifying example of the complex cross talk between pathways involved in morphogenesis and stress response.
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Affiliation(s)
- Virginia Basso
- Unité Biologie et Pathogénicité Fongiques, Institut Pasteur, INRA, 25 Rue Du Docteur Roux, 75015, Paris, France.,Univ. Paris Diderot, Sorbonne Paris Cité, Cellule Pasteur, 25 Rue Du Docteur Roux, Paris, France.,Department of Pathology and Laboratory Medicine, Norris Comprehensive Cancer Center, Keck School of Medicine, University of Southern California, Los Angeles, CA, USA
| | - Christophe d'Enfert
- Unité Biologie et Pathogénicité Fongiques, Institut Pasteur, INRA, 25 Rue Du Docteur Roux, 75015, Paris, France
| | - Sadri Znaidi
- Unité Biologie et Pathogénicité Fongiques, Institut Pasteur, INRA, 25 Rue Du Docteur Roux, 75015, Paris, France. .,Institut Pasteur de Tunis, University of Tunis El Manar, Laboratoire de Microbiologie Moléculaire, Vaccinologie et Développement Biotechnologique, 13 Place Pasteur, 1002, Tunis-Belvédère, Tunisia.
| | - Sophie Bachellier-Bassi
- Unité Biologie et Pathogénicité Fongiques, Institut Pasteur, INRA, 25 Rue Du Docteur Roux, 75015, Paris, France.
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67
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Pentland DR, Piper-Brown E, Mühlschlegel FA, Gourlay CW. Ras signalling in pathogenic yeasts. MICROBIAL CELL 2017; 5:63-73. [PMID: 29417055 PMCID: PMC5798406 DOI: 10.15698/mic2018.02.612] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
The small GTPase Ras acts as a master regulator of growth, stress response and cell death in eukaryotic cells. The control of Ras activity is fundamental, as highlighted by the oncogenic properties of constitutive forms of Ras proteins. Ras also plays a crucial role in the pathogenicity of fungal pathogens where it has been found to regulate a number of adaptions required for virulence. The importance of Ras in fungal disease raises the possibility that it may provide a useful target for the development of new treatments at a time when resistance to available antifungals is increasing. New findings suggest that important regulatory sequences found within fungal Ras proteins that are not conserved may prove useful in the development of new antifungals. Here we review the roles of Ras protein function and signalling in the major human yeast pathogens Candida albicans and Cryptococcus neoformans and discuss the potential for targeting Ras as a novel approach to anti-fungal therapy.
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Affiliation(s)
- Daniel R Pentland
- Kent Fungal Group, School of Biosciences, University of Kent, Canterbury, Kent, United Kingdom, CT2 7NJ
| | - Elliot Piper-Brown
- Kent Fungal Group, School of Biosciences, University of Kent, Canterbury, Kent, United Kingdom, CT2 7NJ
| | - Fritz A Mühlschlegel
- Kent Fungal Group, School of Biosciences, University of Kent, Canterbury, Kent, United Kingdom, CT2 7NJ.,Laboratoire national de santé, 1, Rue Louis Rech, L-3555 Dudelange, Luxembourg
| | - Campbell W Gourlay
- Kent Fungal Group, School of Biosciences, University of Kent, Canterbury, Kent, United Kingdom, CT2 7NJ
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68
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Goffena J, Toenjes KA, Butler DK. Inhibition of yeast-to-filamentous growth transitions in Candida albicans by a small molecule inducer of mammalian apoptosis. Yeast 2017; 35:291-298. [PMID: 29048745 DOI: 10.1002/yea.3287] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2017] [Revised: 09/14/2017] [Accepted: 09/23/2017] [Indexed: 01/09/2023] Open
Abstract
The opportunistic fungal pathogen of humans Candida albicans is able to grow in different morphological forms such as round or oval yeasts and filamentous hyphae and pseudohyphae. Morphogenesis, the ability to switch between the yeast and filamentous growth forms, is important for adapting to new microenvironments in the human host and for pathogenesis. The molecular pathways governing morphogenesis are complex and incompletely understood. Previously, we identified several small organic molecules that specifically inhibit the initiation of hyphal growth in C. albicans without affecting cell viability or budded growth. One molecule from that screen is known to induce apoptosis in mammalian cells. In this study, we have screened additional inducers of mammalian apoptosis and identified BH3I-1, as well as several structural derivatives of BH3I-1, that act as specific inhibitors of morphogenesis under a variety of environmental conditions. Chemical epistasis experiments suggest that BH3I-1 acts downstream of the hypha-specific gene regulators Rfg1, Nrg1 and Ume6.
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Affiliation(s)
- Joy Goffena
- Department of Biological and Physical Sciences, Montana State University - Billings, Billings, Montana, 59101, USA
| | - Kurt A Toenjes
- Department of Biological and Physical Sciences, Montana State University - Billings, Billings, Montana, 59101, USA
| | - David K Butler
- Department of Biological and Physical Sciences, Montana State University - Billings, Billings, Montana, 59101, USA
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69
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Jung SI, Rodriguez N, Irrizary J, Liboro K, Bogarin T, Macias M, Eivers E, Porter E, Filler SG, Park H. Yeast casein kinase 2 governs morphology, biofilm formation, cell wall integrity, and host cell damage of Candida albicans. PLoS One 2017; 12:e0187721. [PMID: 29107946 PMCID: PMC5673188 DOI: 10.1371/journal.pone.0187721] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2017] [Accepted: 10/24/2017] [Indexed: 11/18/2022] Open
Abstract
The regulatory networks governing morphogenesis of a pleomorphic fungus, Candida albicans are extremely complex and remain to be completely elucidated. This study investigated the function of C. albicans yeast casein kinase 2 (CaYck2p). The yck2Δ/yck2Δ strain displayed constitutive pseudohyphae in both yeast and hyphal growth conditions, and formed enhanced biofilm under non-biofilm inducing condition. This finding was further supported by gene expression analysis of the yck2Δ/yck2Δ strain which showed significant upregulation of UME6, a key transcriptional regulator of hyphal transition and biofilm formation, and cell wall protein genes ALS3, HWP1, and SUN41, all of which are associated with morphogenesis and biofilm architecture. The yck2Δ/yck2Δ strain was hypersensitive to cell wall damaging agents and had increased compensatory chitin deposition in the cell wall accompanied by an upregulation of the expression of the chitin synthase genes, CHS2, CHS3, and CHS8. Absence of CaYck2p also affected fungal-host interaction; the yck2Δ/yck2Δ strain had significantly reduced ability to damage host cells. However, the yck2Δ/yck2Δ strain had wild-type susceptibility to cyclosporine and FK506, suggesting that CaYck2p functions independently from the Ca+/calcineurin pathway. Thus, in C. albicans, Yck2p is a multifunctional kinase that governs morphogenesis, biofilm formation, cell wall integrity, and host cell interactions.
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Affiliation(s)
- Sook-In Jung
- Division of Infectious Diseases, Chonnam National University Medical School, Gwangju, South Korea
| | - Natalie Rodriguez
- Department of Biological Sciences, California State University, Los Angeles, Los Angeles, California, United States of America
| | - Jihyun Irrizary
- Department of Biological Sciences, California State University, Los Angeles, Los Angeles, California, United States of America
| | - Karl Liboro
- Department of Biological Sciences, California State University, Los Angeles, Los Angeles, California, United States of America
| | - Thania Bogarin
- Department of Biological Sciences, California State University, Los Angeles, Los Angeles, California, United States of America
| | - Marlene Macias
- Department of Biological Sciences, California State University, Los Angeles, Los Angeles, California, United States of America
| | - Edward Eivers
- Department of Biological Sciences, California State University, Los Angeles, Los Angeles, California, United States of America
| | - Edith Porter
- Department of Biological Sciences, California State University, Los Angeles, Los Angeles, California, United States of America
| | - Scott G. Filler
- Division of Infectious Diseases, Department of Medicine, Los Angeles Biomedical Research Institute at Harbor-UCLA Medical Center, Torrance, California, United States of America
| | - Hyunsook Park
- Department of Biological Sciences, California State University, Los Angeles, Los Angeles, California, United States of America
- * E-mail:
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70
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Hernández-Chávez MJ, Pérez-García LA, Niño-Vega GA, Mora-Montes HM. Fungal Strategies to Evade the Host Immune Recognition. J Fungi (Basel) 2017; 3:jof3040051. [PMID: 29371567 PMCID: PMC5753153 DOI: 10.3390/jof3040051] [Citation(s) in RCA: 71] [Impact Index Per Article: 10.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2017] [Revised: 09/18/2017] [Accepted: 09/19/2017] [Indexed: 12/23/2022] Open
Abstract
The recognition of fungal cells by the host immune system is key during the establishment of a protective anti-fungal response. Even though the immune system has evolved a vast number of processes to control these organisms, they have developed strategies to fight back, avoiding the proper recognition by immune components and thus interfering with the host protective mechanisms. Therefore, the strategies to evade the immune system are as important as the virulence factors and attributes that damage the host tissues and cells. Here, we performed a thorough revision of the main fungal tactics to escape from the host immunosurveillance processes. These include the composition and organization of the cell wall, the fungal capsule, the formation of titan cells, biofilms, and asteroid bodies; the ability to undergo dimorphism; and the escape from nutritional immunity, extracellular traps, phagocytosis, and the action of humoral immune effectors.
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Affiliation(s)
- Marco J Hernández-Chávez
- Departamento de Biología, División de Ciencias Naturales y Exactas, Campus Guanajuato, Universidad de Guanajuato, Noria Alta s/n, col. Noria Alta, C.P., Guanajuato Gto. 36050, México.
| | - Luis A Pérez-García
- Unidad Académica Multidisciplinaria Zona Huasteca, Universidad Autónoma de San Luis Potosí, Romualdo del Campo 501, Fracc. Rafael Curiel, C.P., Cd. Valle SLP. 79060, México.
| | - Gustavo A Niño-Vega
- Departamento de Biología, División de Ciencias Naturales y Exactas, Campus Guanajuato, Universidad de Guanajuato, Noria Alta s/n, col. Noria Alta, C.P., Guanajuato Gto. 36050, México.
| | - Héctor M Mora-Montes
- Departamento de Biología, División de Ciencias Naturales y Exactas, Campus Guanajuato, Universidad de Guanajuato, Noria Alta s/n, col. Noria Alta, C.P., Guanajuato Gto. 36050, México.
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71
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Mishra S, Singh S, Misra K. Restraining Pathogenicity in Candida albicans by Taxifolin as an Inhibitor of Ras1-pka Pathway. Mycopathologia 2017; 182:953-965. [PMID: 28681317 DOI: 10.1007/s11046-017-0170-4] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2017] [Accepted: 06/23/2017] [Indexed: 10/19/2022]
Abstract
Candida albicans is one of the most virulent and opportunistic fungal strains. In the present scenario, majority metabolic imbalances and unsuccessful treatments of some severe diseases including cancer, diabetes, HIV, psoriasis are because of invasive Candida emergence. Being a beneficial integral part of human biome, its elimination is not possible. The major pathogenicity characteristics in Candida involve hyphal growth, biofilm formation, HSP90 down regulation and genetic modifications. Ras1-pka pathway initiated by HSP90 down regulation is important for hyphal growth and has been focused in the present study. The principle transcriptional factors that induce hyphal growth causing invasiveness and virulence through this pathway have been identified as Tec1 and Rfg1. In the present study, taxifolin, a naturally occurring polyphenol, has been identified as inhibitor for both the transcriptional factors in parallel.
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Affiliation(s)
- Sonali Mishra
- Indian Institute of Information Technology, Allahabad, India
| | - Sangeeta Singh
- Indian Institute of Information Technology, Allahabad, India
| | - Krishna Misra
- Indian Institute of Information Technology, Allahabad, India.
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72
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Polke M, Leonhardt I, Kurzai O, Jacobsen ID. Farnesol signalling in Candida albicans – more than just communication. Crit Rev Microbiol 2017; 44:230-243. [DOI: 10.1080/1040841x.2017.1337711] [Citation(s) in RCA: 40] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Affiliation(s)
- Melanie Polke
- Research Group Microbial Immunology, Leibniz Institute for Natural Product Research and Infection Biology, Hans Knoell Institute (HKI), Jena, Germany
| | - Ines Leonhardt
- Septomics Research Center, Friedrich Schiller University and Leibniz Institute for Natural Product Research and Infection Biology – Hans Knoell Institute (HKI), Jena, Germany
- Center for Sepsis Control and Care (CSCC), University Hospital, Jena, Germany
| | - Oliver Kurzai
- Septomics Research Center, Friedrich Schiller University and Leibniz Institute for Natural Product Research and Infection Biology – Hans Knoell Institute (HKI), Jena, Germany
- Center for Sepsis Control and Care (CSCC), University Hospital, Jena, Germany
- Friedrich Schiller University, Jena, Germany
| | - Ilse D. Jacobsen
- Research Group Microbial Immunology, Leibniz Institute for Natural Product Research and Infection Biology, Hans Knoell Institute (HKI), Jena, Germany
- Center for Sepsis Control and Care (CSCC), University Hospital, Jena, Germany
- Friedrich Schiller University, Jena, Germany
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73
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Bijlani S, Nahar AS, Ganesan K. Improved Tet-On and Tet-Off systems for tetracycline-regulated expression of genes in Candida. Curr Genet 2017; 64:303-316. [DOI: 10.1007/s00294-017-0720-9] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2017] [Revised: 05/27/2017] [Accepted: 06/02/2017] [Indexed: 10/19/2022]
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74
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Woolford CA, Lagree K, Aleynikov T, Mitchell AP. Negative control of Candida albicans filamentation-associated gene expression by essential protein kinase gene KIN28. Curr Genet 2017; 63:1073-1079. [PMID: 28501989 DOI: 10.1007/s00294-017-0705-8] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2017] [Revised: 04/25/2017] [Accepted: 05/10/2017] [Indexed: 12/31/2022]
Abstract
The fungus Candida albicans can grow as either yeast or filaments, which include hyphae and pseudohyphae, depending on environmental conditions. Filamentous growth is of particular interest because it is required for biofilm formation and for pathogenesis. Environmentally induced filamentous growth is associated with expression of filamentation-associated genes, and both filamentous growth and associated gene expression depend upon several well-characterized transcription factors. Surprisingly, strains with reduced expression of many essential genes display filamentous growth under non-inducing conditions-those in which the wild type grows as yeast. We found recently that diminished expression of several essential protein kinase genes leads to both filamentous cell morphology and filamentation-associated gene expression under non-inducing conditions. Reduced expression of the essential protein kinase gene CAK1 promoted filamentation-associated gene expression and biofilm formation in strains that lacked key transcriptional activators of these processes, thus indicating that CAK1 expression is critical for both environmental and genetic control of filamentation. In this study, we extend our genetic interaction analysis to a second essential protein kinase gene, KIN28. Reduced expression of KIN28 also permits filamentation-associated gene expression, though not biofilm formation, in the absence of several key transcriptional activators. Our results argue that impairment of several essential cellular processes can alter the regulatory requirements for filamentation-associated gene expression. Our results also indicate that levels of filamentation-associated gene expression are not fully predictive of biofilm formation ability.
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Affiliation(s)
- C A Woolford
- Department of Biological Sciences, Carnegie Mellon University, Pittsburgh, PA, USA
| | - K Lagree
- Department of Biological Sciences, Carnegie Mellon University, Pittsburgh, PA, USA
| | - T Aleynikov
- Department of Biological Sciences, Carnegie Mellon University, Pittsburgh, PA, USA
| | - A P Mitchell
- Department of Biological Sciences, Carnegie Mellon University, Pittsburgh, PA, USA.
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75
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Ahn CH, Lee S, Cho E, Kim H, Chung B, Park W, Shin J, Oh KB. A farnesoic acid-responsive transcription factor, Hot1, regulates yeast-hypha morphogenesis in Candida albicans. FEBS Lett 2017; 591:1225-1235. [PMID: 28369931 DOI: 10.1002/1873-3468.12636] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2017] [Revised: 03/21/2017] [Accepted: 03/23/2017] [Indexed: 12/22/2022]
Abstract
Candida albicans hyphal formation is inhibited by a quorum-sensing molecule, farnesoic acid, which accumulates in the medium as the cells proliferate. We recently showed that Pho81 is essential for the inhibition of hyphal growth by farnesoic acid. Here, we describe a newly identified regulator, Hot1, which increases the expression of PHO81. The binding site of Hot1 in the PHO81 promoter region was identified by DNase I protection assay. The hot1Δ mutant grows extensively as filaments. Furthermore, the inhibition of hyphal formation and the repression of major signaling pathway components in response to farnesoic acid are defective in hot1Δ mutant cells. These data suggest an important role for HOT1 in the inhibition of hyphal development by farnesoic acid in this fungus.
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Affiliation(s)
- Chan-Hong Ahn
- Department of Agricultural Biotechnology, College of Agriculture and Life Sciences, Seoul National University, Korea
| | - Sohyoung Lee
- Department of Agricultural Biotechnology, College of Agriculture and Life Sciences, Seoul National University, Korea
| | - Eunji Cho
- Department of Agricultural Biotechnology, College of Agriculture and Life Sciences, Seoul National University, Korea
| | - Heegyu Kim
- Department of Agricultural Biotechnology, College of Agriculture and Life Sciences, Seoul National University, Korea
| | - Beomkoo Chung
- Department of Agricultural Biotechnology, College of Agriculture and Life Sciences, Seoul National University, Korea
| | - Wanki Park
- Department of Agricultural Biotechnology, College of Agriculture and Life Sciences, Seoul National University, Korea
| | - Jongheon Shin
- Natural Products Research Institute, College of Pharmacy, Seoul National University, Korea
| | - Ki-Bong Oh
- Department of Agricultural Biotechnology, College of Agriculture and Life Sciences, Seoul National University, Korea
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76
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Mendelsohn S, Pinsky M, Weissman Z, Kornitzer D. Regulation of the Candida albicans Hypha-Inducing Transcription Factor Ume6 by the CDK1 Cyclins Cln3 and Hgc1. mSphere 2017; 2:e00248-16. [PMID: 28289726 PMCID: PMC5343172 DOI: 10.1128/msphere.00248-16] [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: 08/22/2016] [Accepted: 02/20/2017] [Indexed: 01/17/2023] Open
Abstract
The ability to switch between proliferation as yeast cells and development into hyphae is a hallmark of Candida albicans. The switch to hyphal morphogenesis depends on external inducing conditions, but its efficiency is augmented in stationary-phase cells. Ume6, a transcription factor that is itself transcriptionally induced under hypha-promoting conditions, is both necessary and sufficient for hyphal morphogenesis. We found that Ume6 is regulated posttranslationally by the cell cycle kinase Cdc28/Cdk1, which reduces Ume6 activity via different mechanisms using different cyclins. Together with the cyclin Hgc1, Cdk1 promotes degradation of Ume6 via the SCFCDC4 ubiquitin ligase. Since HGC1 is a key transcriptional target of Ume6, this results in a negative-feedback loop between Hgc1 and Ume6. In addition, we found that Cln3, a G1 cyclin that is essential for cell cycle progression and yeast proliferation, suppresses hyphal morphogenesis and that Cln3 suppresses Ume6 activity both in the heterologous Saccharomyces cerevisiae system and in C. albicans itself. This activity of Cln3 may provide the basis for the antagonistic relationship between yeast proliferation and hyphal development in C. albicans. IMPORTANCE The yeast to hypha (mold) morphogenetic switch of Candida albicans plays a role in its virulence and constitutes a diagnostic trait for this organism, the most prevalent systemic fungal pathogen in industrialized countries. It has long been known that hyphae are most efficiently induced from stationary cultures. Here, a molecular basis for this observation is provided. The G1 cyclin Cln3, an essential promoter of yeast proliferation, was found to suppress hyphal induction. Suppression of hyphal induction is achieved by inhibition of the activity of the central activator of hyphal morphogenesis, the transcription factor Ume6. Thus, levels of Cln3 control the switch between proliferation of C. albicans as individual yeast cells and development into extended hyphae, a switch that may preface the proliferation/differentiation switch in multicellular organisms.
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Affiliation(s)
- Sigal Mendelsohn
- Department of Molecular Microbiology, B. Rappaport Faculty of Medicine, Technion-I.I.T. and the Rappaport Institute for Research in the Medical Sciences, Haifa, Israel
| | - Mariel Pinsky
- Department of Molecular Microbiology, B. Rappaport Faculty of Medicine, Technion-I.I.T. and the Rappaport Institute for Research in the Medical Sciences, Haifa, Israel
| | - Ziva Weissman
- Department of Molecular Microbiology, B. Rappaport Faculty of Medicine, Technion-I.I.T. and the Rappaport Institute for Research in the Medical Sciences, Haifa, Israel
| | - Daniel Kornitzer
- Department of Molecular Microbiology, B. Rappaport Faculty of Medicine, Technion-I.I.T. and the Rappaport Institute for Research in the Medical Sciences, Haifa, Israel
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Masuda R, Iguchi N, Tukuta K, Nagoshi T, Kemuriyama K, Muraguchi H. The Coprinopsis cinerea Tup1 homologue Cag1 is required for gill formation during fruiting body morphogenesis. Biol Open 2016; 5:1844-1852. [PMID: 27815245 PMCID: PMC5200907 DOI: 10.1242/bio.021246] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The pileus (cap) of the fruiting body in homobasidiomycete fungi bears the hymenium, a layer of cells that includes the basidia where nuclear fusion, meiosis and sporulation occur. Coprinopsis cinerea is a model system for studying fruiting body development. The hymenium of C. cinerea forms at the surface of the gills in the pileus. In a previous study, we identified a mutation called cap-growthless1-1 (cag1-1) that blocks gill formation, which yields primordia that never mature. In this study, we found that the cag1 gene encodes a homologue of Saccharomyces cerevisiae Tup1. The C. cinerea genome contains another Tup1 homologue gene called Cc.tupA. Reciprocal tagging of Cag1 and Cc.TupA with green and red fluorescent proteins revealed that the relative ratios of the amounts of the two Tup1 paralogues varied among tissues. Compared with Cc.TupA, Cag1 was preferentially expressed in the gill trama tissue cells, suggesting that the function of Cag1 is required for gill trama tissue differentiation and maintenance. Yeast two-hybrid analysis and co-localisation of Cag1 and Cc.TupA suggested that Cag1 interacts with Cc.TupA in the nuclei of certain cells. Summary: Cag1, a Tup1 homologue in Coprinopsis cinerea, is required for gill formation in fruiting body development and is highly expressed in the central region of gills.
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Affiliation(s)
- Ryo Masuda
- Department of Biotechnology, Faculty of Bioresource Sciences, Akita Prefectural University, Akita 010-0195, Japan
| | - Naoki Iguchi
- Department of Biotechnology, Faculty of Bioresource Sciences, Akita Prefectural University, Akita 010-0195, Japan
| | - Kooki Tukuta
- Department of Biotechnology, Faculty of Bioresource Sciences, Akita Prefectural University, Akita 010-0195, Japan
| | - Takahiro Nagoshi
- Department of Biotechnology, Faculty of Bioresource Sciences, Akita Prefectural University, Akita 010-0195, Japan
| | - Kazuki Kemuriyama
- Department of Biotechnology, Faculty of Bioresource Sciences, Akita Prefectural University, Akita 010-0195, Japan
| | - Hajime Muraguchi
- Department of Biotechnology, Faculty of Bioresource Sciences, Akita Prefectural University, Akita 010-0195, Japan
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78
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Dongari-Bagtzoglou A, Fidel PL. The Host Cytokine Responses and Protective Immunity in Oropharyngeal Candidiasis. J Dent Res 2016; 84:966-77. [PMID: 16246925 DOI: 10.1177/154405910508401101] [Citation(s) in RCA: 93] [Impact Index Per Article: 11.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
Over the last three decades, the prevalence of oropharyngeal fungal infections has increased enormously, mainly due to an increasing population of immunocompromised patients, including individuals with HIV infection, transplant recipients, and patients receiving cancer therapy. The vast majority of these infections are caused by Candida species. The presence of cytokines in infected tissues ultimately dictates the host defense processes that are specific to each pathogenic organism. During oral infection with Candida, a large number of pro-inflammatory and immunoregulatory cytokines are generated in the oral mucosa. The main sources of these cytokines are oral epithelial cells, which maintain a central role in the protection against fungal organisms. These cytokines may drive the chemotaxis and effector functions of innate and/or adaptive effector cells, such as infiltrating neutrophils and T-cells in immunocompetent hosts, and CD8+ T-cells in HIV+ hosts. Epithelial cells also have direct anti- Candida activity. Several studies have provided a potential link between lower levels of certain pro-inflammatory cytokines and susceptibility to oral C. albicans infection, suggesting that such cytokines may be involved in immune protection. The exact role of these cytokines in immune protection against oropharyngeal candidiasis is still incompletely understood and requires further investigation. Identification of such cytokines with the ability to enhance anti-fungal activities of immune effector cells may have therapeutic implications in the treatment of this oral infection in the severely immunocompromised host.
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Affiliation(s)
- A Dongari-Bagtzoglou
- School of Dental Medicine, Department of Oral Health and Diagnostic Sciences, University of Connecticut, 263 Farmington Ave., Farmington, CT 06030-1710, USA.
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79
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Noble SM, Gianetti BA, Witchley JN. Candida albicans cell-type switching and functional plasticity in the mammalian host. Nat Rev Microbiol 2016; 15:96-108. [PMID: 27867199 DOI: 10.1038/nrmicro.2016.157] [Citation(s) in RCA: 331] [Impact Index Per Article: 41.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Candida albicans is a ubiquitous commensal of the mammalian microbiome and the most prevalent fungal pathogen of humans. A cell-type transition between yeast and hyphal morphologies in C. albicans was thought to underlie much of the variation in virulence observed in different host tissues. However, novel yeast-like cell morphotypes, including opaque(a/α), grey and gastrointestinally induced transition (GUT) cell types, were recently reported that exhibit marked differences in vitro and in animal models of commensalism and disease. In this Review, we explore the characteristics of the classic cell types - yeast, hyphae, pseudohyphae and chlamydospores - as well as the newly identified yeast-like morphotypes. We highlight emerging knowledge about the associations of these different morphotypes with different host niches and virulence potential, as well as the environmental cues and signalling pathways that are involved in the morphological transitions.
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Affiliation(s)
- Suzanne M Noble
- Department of Microbiology and Immunology, University of California San Francisco (UCSF) School of Medicine.,Infectious Diseases Division, Department of Medicine, University of California San Francisco (UCSF) School of Medicine, San Francisco, California 94143, USA
| | - Brittany A Gianetti
- Department of Microbiology and Immunology, University of California San Francisco (UCSF) School of Medicine
| | - Jessica N Witchley
- Department of Microbiology and Immunology, University of California San Francisco (UCSF) School of Medicine
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80
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Kadosh D. Control of Candida albicans morphology and pathogenicity by post-transcriptional mechanisms. Cell Mol Life Sci 2016; 73:4265-4278. [PMID: 27312239 PMCID: PMC5582595 DOI: 10.1007/s00018-016-2294-y] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2016] [Revised: 05/23/2016] [Accepted: 06/10/2016] [Indexed: 02/01/2023]
Abstract
Candida albicans is a major human fungal pathogen responsible for both systemic and mucosal infections in a wide variety of immunocompromised individuals. Because the ability of C. albicans to undergo a reversible morphological transition from yeast to filaments is important for virulence, significant research efforts have focused on mechanisms that control this transition. While transcriptional and post-translational mechanisms have been well-studied, considerably less is known about the role of post-transcriptional mechanisms. However, in recent years several discoveries have begun to shed light on this important, but understudied, area. Here, I will review a variety of post-transcriptional mechanisms that have recently been shown to control C. albicans morphology, virulence and/or virulence-related processes, including those involving alternative transcript localization, mRNA stability and translation. I will also discuss the role that these mechanisms play in other pathogens as well as the potential they may hold to serve as targets for new antifungal strategies. Ultimately, gaining a better understanding of C. albicans post-transcriptional mechanisms will significantly improve our knowledge of how morphogenesis and virulence are controlled in fungal pathogens and open new avenues for the development of novel and more effective antifungals.
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Affiliation(s)
- David Kadosh
- Department of Microbiology and Immunology, University of Texas Health Science, Center at San Antonio, 7703 Floyd Curl Drive, MC: 7758, San Antonio, TX, 78229, USA.
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81
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Signaling through Lrg1, Rho1 and Pkc1 Governs Candida albicans Morphogenesis in Response to Diverse Cues. PLoS Genet 2016; 12:e1006405. [PMID: 27788136 PMCID: PMC5082861 DOI: 10.1371/journal.pgen.1006405] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2016] [Accepted: 10/04/2016] [Indexed: 12/22/2022] Open
Abstract
The capacity to transition between distinct morphological forms is a key virulence trait for diverse fungal pathogens. A poignant example of a leading opportunistic fungal pathogen of humans for which an environmentally responsive developmental program underpins virulence is Candida albicans. C. albicans mutants that are defective in the transition between yeast and filamentous forms typically have reduced virulence. Although many positive regulators of C. albicans filamentation have been defined, there are fewer negative regulators that have been implicated in repression of filamentation in the absence of inducing cues. To discover novel negative regulators of filamentation, we screened a collection of 1,248 C. albicans homozygous transposon insertion mutants to identify those that were filamentous in the absence of inducing cues. We identified the Rho1 GAP Lrg1, which represses filamentous growth by stimulating Rho1 GTPase activity and converting Rho1 to its inactive, GDP-bound form. Deletion of LRG1 or introduction of a RHO1 mutation that locks Rho1 in constitutively active, GTP-bound state, leads to filamentation in the absence of inducing cues. Deletion of the Rho1 downstream effector PKC1 results in defective filamentation in response to diverse host-relevant inducing cues, including serum. We further established that Pkc1 is not required to sense filament-inducing cues, but its kinase activity is critical for the initiation of filamentous growth. Our genetic analyses revealed that Pkc1 regulates filamentation independent of the canonical MAP kinase cascade. Further, although Ras1 activation is not impaired in a pkc1Δ/pkc1Δ mutant, adenylyl cyclase activity is reduced, consistent with a model in which Pkc1 functions in parallel with Ras1 in regulating Cyr1 activation. Thus, our findings delineate a signaling pathway comprised of Lrg1, Rho1 and Pkc1 with a core role in C. albicans morphogenesis, and illuminate functional relationships that govern activation of a central transducer of signals that control environmental response and virulence programs.
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82
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Lee K, Lee S, Lee SH, Kim SR, Oh HS, Park PK, Choo KH, Kim YW, Lee JK, Lee CH. Fungal Quorum Quenching: A Paradigm Shift for Energy Savings in Membrane Bioreactor (MBR) for Wastewater Treatment. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2016; 50:10914-10922. [PMID: 27634354 DOI: 10.1021/acs.est.6b00313] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/06/2023]
Abstract
In the last 30 years, the use of membrane bioreactors (MBRs) for advanced wastewater treatment and reuse have been expanded continuously, but they still suffer from excessive energy consumption resulting from the intrinsic problem of membrane biofouling. One of the major causes of biofouling in MBRs is bacterial quorum sensing (QS) via N-acylhomoserine lactones (AHLs) and/or autoinducer-2 (AI-2), enabling intra- and interspecies communications, respectively. In this study, we demonstrate that farnesol can substantially mitigate membrane biofouling in a MBR due to its quorum quenching (QQ) activity. When Candida albicans (a farnesol producing fungus) entrapping polymer beads (AEBs) were placed in the MBR, the rate of transmembrane pressure (TMP) rise-up was substantially decreased, even for lower aeration intensities. This finding corresponds to a specific aeration energy savings of approximately 40% (25% through the physical washing effect and a further 15% through the biological QQ effect of AEBs) compared to conventional MBRs without AEBs. A real-time RT-qPCR analysis revealed that farnesol secreted from C. albicans mitigated the biofilm formation in MBRs via the suppression of AI-2 QS. Successful control of biofouling and energy savings through fungal-to-bacterial QQ could be expanded to the plant scale for MBRs in wastewater treatment with economic feasibility.
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Affiliation(s)
- Kibaek Lee
- School of Chemical and Biological Engineering, Seoul National University , Seoul, 08826, Republic of Korea
| | - Seonki Lee
- School of Chemical and Biological Engineering, Seoul National University , Seoul, 08826, Republic of Korea
| | - Sang Hyun Lee
- School of Chemical and Biological Engineering, Seoul National University , Seoul, 08826, Republic of Korea
| | - Sang-Ryoung Kim
- School of Chemical and Biological Engineering, Seoul National University , Seoul, 08826, Republic of Korea
| | - Hyun-Suk Oh
- School of Chemical and Biological Engineering, Seoul National University , Seoul, 08826, Republic of Korea
| | - Pyung-Kyu Park
- Department of Environmental Engineering, Yonsei University , Wonju, 26493, Republic of Korea
| | - Kwang-Ho Choo
- Department of Environmental Engineering, Kyungpook National University , Daegu, 41566, Republic of Korea
| | - Yea-Won Kim
- Department of Biomedicinal Science and Biotechnology, Paichai University , Daejeon 35345, Republic of Korea
| | - Jung-Kee Lee
- Department of Biomedicinal Science and Biotechnology, Paichai University , Daejeon 35345, Republic of Korea
| | - Chung-Hak Lee
- School of Chemical and Biological Engineering, Seoul National University , Seoul, 08826, Republic of Korea
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83
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Ku M, Baek YU, Kwak MK, Kang SO. Candida albicans glutathione reductase downregulates Efg1-mediated cyclic AMP/protein kinase A pathway and leads to defective hyphal growth and virulence upon decreased cellular methylglyoxal content accompanied by activating alcohol dehydrogenase and glycolytic enzymes. Biochim Biophys Acta Gen Subj 2016; 1861:772-788. [PMID: 27751952 DOI: 10.1016/j.bbagen.2016.10.010] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2016] [Revised: 09/23/2016] [Accepted: 10/13/2016] [Indexed: 12/30/2022]
Abstract
BACKGROUND Glutathione reductase maintains the glutathione level in a reduced state. As previously demonstrated, glutathione is required for cell growth/division and its biosynthesizing-enzyme deficiency causes methylglyoxal accumulation. However, experimental evidences for reciprocal relationships between Cph1-/Efg1-mediated signaling pathway regulation and methylglyoxal production exerted by glutathione reductase on yeast morphology remain unclear. METHODS Glutathione reductase (GLR1) disruption/overexpression were performed to investigate aspects of pathological/morphological alterations in Candida albicans. These assumptions were proved by observations of cellular susceptibility to oxidants and thiols, and measurements of methylglyoxal and glutathione content in hyphal-inducing conditions mainly through the activity of GLR1-overexpressing cells. Additionally, the transcriptional/translational levels of bioenergetic enzymes and dimorphism-regulating protein kinases were examined in the strain. RESULTS The GLR1-deficient strain was non-viable when GLR1 expression under the control of a CaMAL2 promoter was conditionally repressed, despite partial rescue of growth by exogenous thiols. During filamentation, non-growing hyphal GLR1-overexpressing cells exhibited resistance against oxidants and cellular methylglyoxal was significantly decreased, which concomitantly increased expressions of genes encoding energy-generating enzymes, including fructose-1,6-bisphosphate aldolase, glyceraldehyde-3-phosphate dehydrogenase, and alcohol dehydrogenase (ADH1), with remarkable repression of Efg1-signaling cascades. CONCLUSIONS This is the first report that GLR1-triggered Efg1-mediated signal transduction repression strictly reduces dimorphic switching and virulence by maintaining the basal level of methylglyoxal following the enhanced gene expressions of glycolytic enzymes and ADH1. GENERAL SIGNIFICANCE The Efg1 downregulatory mechanism by GLR1 expression has possibilities to involve in other complex network of signal pathways. Understanding how GLR1 overexpression affects multiple signaling pathways can help identify attractive targets for antifungal drugs.
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Affiliation(s)
- MyungHee Ku
- Laboratory of Biophysics, School of Biological Sciences, and Institute of Microbiology, Seoul National University, Seoul 151-742, Republic of Korea
| | - Yong-Un Baek
- Laboratory of Biophysics, School of Biological Sciences, and Institute of Microbiology, Seoul National University, Seoul 151-742, Republic of Korea
| | - Min-Kyu Kwak
- Laboratory of Biophysics, School of Biological Sciences, and Institute of Microbiology, Seoul National University, Seoul 151-742, Republic of Korea.
| | - Sa-Ouk Kang
- Laboratory of Biophysics, School of Biological Sciences, and Institute of Microbiology, Seoul National University, Seoul 151-742, Republic of Korea.
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84
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Polke M, Sprenger M, Scherlach K, Albán-Proaño MC, Martin R, Hertweck C, Hube B, Jacobsen ID. A functional link between hyphal maintenance and quorum sensing in Candida albicans. Mol Microbiol 2016; 103:595-617. [PMID: 27623739 DOI: 10.1111/mmi.13526] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 09/07/2016] [Indexed: 01/04/2023]
Abstract
Morphogenesis in Candida albicans requires hyphal initiation and maintenance, and both processes are regulated by the fungal quorum sensing molecule (QSM) farnesol. We show that deletion of C. albicans EED1, which is crucial for hyphal extension and maintenance, led to a dramatically increased sensitivity to farnesol, and thus identified the first mutant hypersensitive to farnesol. Furthermore, farnesol decreased the transient filamentation of an eed1Δ strain without inducing cell death, indicating that two separate mechanisms mediate quorum sensing and cell lysis by farnesol. To analyze the cause of farnesol hypersensitivity we constructed either hyperactive or deletion mutants of factors involved in farnesol signaling, by introducing the hyperactive RAS1G13V or pADH1-CYR1CAT allele, or deleting CZF1 or NRG1 respectively. Neither of the constructs nor the exogenous addition of dB-cAMP was able to rescue the farnesol hypersensitivity, highlighting that farnesol mediates its effects not only via the cAMP pathway. Interestingly, the eed1Δ strain also displayed increased farnesol production. When eed1Δ was grown under continuous medium flow conditions, to remove accumulating QSMs from the supernatant, maintenance of eed1Δ filamentation, although not restored, was significantly prolonged, indicating a link between farnesol sensitivity, production, and the hyphal maintenance-defect in the eed1Δ mutant strain.
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Affiliation(s)
- Melanie Polke
- Research Group Microbial Immunology, Leibniz Institute for Natural Product Research and Infection Biology, Hans Knoell Institute (HKI), Jena, Germany
| | - Marcel Sprenger
- Department of Microbial Pathogenicity Mechanisms, Leibniz Institute for Natural Product Research and Infection Biology, Hans Knoell Institute (HKI), Jena, Germany
| | - Kirstin Scherlach
- Department of Biomolecular Chemistry, Leibniz Institute for Natural Product Research and Infection Biology, Hans Knoell Institute (HKI), Jena, Germany
| | - María Cristina Albán-Proaño
- Department of Microbial Pathogenicity Mechanisms, Leibniz Institute for Natural Product Research and Infection Biology, Hans Knoell Institute (HKI), Jena, Germany
| | - Ronny Martin
- Department of Microbial Pathogenicity Mechanisms, Leibniz Institute for Natural Product Research and Infection Biology, Hans Knoell Institute (HKI), Jena, Germany
| | - Christian Hertweck
- Department of Biomolecular Chemistry, Leibniz Institute for Natural Product Research and Infection Biology, Hans Knoell Institute (HKI), Jena, Germany.,Friedrich Schiller University, Jena, Germany
| | - Bernhard Hube
- Department of Microbial Pathogenicity Mechanisms, Leibniz Institute for Natural Product Research and Infection Biology, Hans Knoell Institute (HKI), Jena, Germany.,Friedrich Schiller University, Jena, Germany.,Integrated Research and Treatment Center, Center for Sepsis Control and Care (CSCC), University Hospital, Jena, Germany
| | - Ilse D Jacobsen
- Research Group Microbial Immunology, Leibniz Institute for Natural Product Research and Infection Biology, Hans Knoell Institute (HKI), Jena, Germany.,Friedrich Schiller University, Jena, Germany.,Integrated Research and Treatment Center, Center for Sepsis Control and Care (CSCC), University Hospital, Jena, Germany
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85
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Wang Y. Hgc1-Cdc28-how much does a single protein kinase do in the regulation of hyphal development in Candida albicans? J Microbiol 2016; 54:170-7. [PMID: 26920877 DOI: 10.1007/s12275-016-5550-9] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2015] [Revised: 12/03/2015] [Accepted: 12/03/2015] [Indexed: 01/06/2023]
Abstract
The fungal human pathogen Candida albicans can cause invasive infection with high mortality rates. A key virulence factor is its ability to switch between three morphologies: yeast, pseudohyphae and hyphae. In contrast to the ovalshaped unicellular yeast cells, hyphae are highly elongated, tube-like, and multicellular. A long-standing question is what coordinates all the cellular machines to construct cells with distinct shapes. Hyphal-specific genes (HSGs) are thought to hold the answer. Among the numerous HSGs found, only UME6 and HGC1 are required for hyphal development. UME6 encodes a transcription factor that regulates many HSGs including HGC1. HGC1 encodes a G1 cyclin which partners with the Cdc28 cyclin-dependent kinase. Hgc1-Cdc28 simultaneously phosphorylates and regulates multiple substrates, thus controlling multiple cellular apparatuses for morphogenesis. This review is focused on major progresses made in the past decade on Hgc1's roles and regulation in C. albicans hyphal development and other traits important for infection.
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Affiliation(s)
- Yue Wang
- Candida albicans Biology Laboratory, Institute of Molecular and Cell Biology, Agency for Science, Technology, and Research, and Department of Biochemistry, Yong Loo Lin School of Medicine, National University of Singapore, Singapore, Singapore.
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86
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Cleary IA, Reinhard SM, Lazzell AL, Monteagudo C, Thomas DP, Lopez-Ribot JL, Saville SP. Examination of the pathogenic potential of Candida albicans filamentous cells in an animal model of haematogenously disseminated candidiasis. FEMS Yeast Res 2016; 16:fow011. [PMID: 26851404 DOI: 10.1093/femsyr/fow011] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 02/01/2016] [Indexed: 11/12/2022] Open
Abstract
The opportunistic fungal pathogen Candida albicans is an increasingly common threat to human health. Candida albicans grows in several morphologies and mutant strains locked in yeast or filamentous forms have attenuated virulence in the murine model of disseminated candidiasis. Thus, the ability to change shape is important for virulence. The transcriptional repressors Nrg1p and Tup1p are required for normal regulation of C. albicans morphology. Strains lacking either NRG1 or TUP1 are constitutively pseudohyphal under yeast growth conditions, and display attenuated virulence in the disseminated model. To dissect the relative importance of hyphae and pseudohyphae during an infection, we used strains in which the morphological transition could be externally manipulated through controlled expression of NRG1 or TUP1. Remarkably, hyphal form inocula retain the capacity to cause disease. Whilst induction of a pseudohyphal morphology through depletion of TUP1 did result in attenuated virulence, this was not due to a defect in the ability to escape the bloodstream. Instead, we observed that pseudohyphal cells are cleared from tissues much more efficiently than either hyphal (virulent) or yeast form (avirulent) cells, indicating that different C. albicans morphologies have distinct interactions with host cells during an infection.
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Affiliation(s)
- Ian A Cleary
- Department of Biological Sciences, The University of Tennessee at Martin, Martin, TN 38238, USA
| | - Sara M Reinhard
- Department of Biology, and The South Texas Center for Emerging Infectious Diseases, The University of Texas at San Antonio, San Antonio, TX 78249, USA
| | - Anna L Lazzell
- Department of Biology, and The South Texas Center for Emerging Infectious Diseases, The University of Texas at San Antonio, San Antonio, TX 78249, USA
| | - Carlos Monteagudo
- Departamento de Patologia, Facultad de Medicina y Odontologia, Universidad de Valencia, Avda. Blasco Ibañez, 17, 46010 Valencia, España
| | - Derek P Thomas
- Department of Biomedical Sciences, Grand Valley State University, 1 Campus Drive, Allendale, MI 49401, USA
| | - Jose L Lopez-Ribot
- Department of Biology, and The South Texas Center for Emerging Infectious Diseases, The University of Texas at San Antonio, San Antonio, TX 78249, USA
| | - Stephen P Saville
- Department of Biology, and The South Texas Center for Emerging Infectious Diseases, The University of Texas at San Antonio, San Antonio, TX 78249, USA
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87
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Gonia S, Larson B, Gale CA. PCR-mediated gene modification strategy for construction of fluorescent protein fusions in Candida parapsilosis. Yeast 2016; 33:63-9. [PMID: 26551241 DOI: 10.1002/yea.3141] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2015] [Revised: 11/01/2015] [Accepted: 11/02/2015] [Indexed: 11/07/2022] Open
Abstract
Candida parapsilosis is a common cause of invasive candidiasis, especially in premature infants, even surpassing Candida albicans as the most frequently identified Candida species in some newborn intensive care units. Whereas many molecular tools are available to facilitate the study of C. albicans, relatively few have been developed for C. parapsilosis. In this study, we show that plasmids harbouring green, yellow and mCherry fluorescent protein sequences, previously developed for expression in C. albicans, can be used to construct fluorescent fusion proteins in C. parapsilosis by PCR-mediated gene modification. Further, the strategy can be used in clinical isolates of C. parapsilosis, which are typically prototrophic, because the plasmids include NAT1, a dominant selectable trait that confers resistance to the antibiotic nourseothricin. Overall, these tools will be useful to yeast researchers who require the ability to visualize C. parapsilosis directly, e.g. in in vitro and in vivo infection models. In addition, this strategy can be used to generate fluorescence in other C. parapsilosis clinical isolates and to tag sequences of interest for protein localization studies. Lastly, the ability to express up to three different fluorescent proteins will allow researchers to visualize and differentiate C. parapsilosis and/or C. albicans clinical isolates from each other in mixed infection models.
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Affiliation(s)
- Sara Gonia
- Department of Pediatrics, University of Minnesota, Minneapolis, MN, USA
| | - Britta Larson
- Department of Pediatrics, University of Minnesota, Minneapolis, MN, USA
| | - Cheryl A Gale
- Department of Pediatrics, University of Minnesota, Minneapolis, MN, USA
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88
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Ghosh AK, Wangsanut T, Fonzi WA, Rolfes RJ. The GRF10 homeobox gene regulates filamentous growth in the human fungal pathogen Candida albicans. FEMS Yeast Res 2015; 15:fov093. [PMID: 26472755 PMCID: PMC4705307 DOI: 10.1093/femsyr/fov093] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Revised: 08/14/2015] [Accepted: 10/07/2015] [Indexed: 12/14/2022] Open
Abstract
Candida albicans is the most common human fungal pathogen and can cause life-threatening infections. Filamentous growth is critical in the pathogenicity of C. albicans, as the transition from yeast to hyphal forms is linked to virulence and is also a pivotal process in fungal biofilm development. Homeodomain-containing transcription factors have been linked to developmental processes in fungi and other eukaryotes. We report here on GRF10, a homeobox transcription factor-encoding gene that plays a role in C. albicans filamentation. Deletion of the GRF10 gene, in both C. albicans SN152 and BWP17 strain backgrounds, results in mutants with strongly decreased hyphal growth. The mutants are defective in chlamydospore and biofilm formation, as well as showing dramatically attenuated virulence in a mouse infection model. Expression of the GRF10 gene is highly induced during stationary phase and filamentation. In summary, our study emphasizes a new role for the homeodomain-containing transcription factor in morphogenesis and pathogenicity of C. albicans.
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Affiliation(s)
- Anup K Ghosh
- Department of Biology, Georgetown University, Washington, DC 20057, USA
| | | | - William A Fonzi
- Department of Microbiology and Immunology, Georgetown University, Washington, DC 20057, USA
| | - Ronda J Rolfes
- Department of Biology, Georgetown University, Washington, DC 20057, USA
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89
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Kim SH, Clark ST, Surendra A, Copeland JK, Wang PW, Ammar R, Collins C, Tullis DE, Nislow C, Hwang DM, Guttman DS, Cowen LE. Global Analysis of the Fungal Microbiome in Cystic Fibrosis Patients Reveals Loss of Function of the Transcriptional Repressor Nrg1 as a Mechanism of Pathogen Adaptation. PLoS Pathog 2015; 11:e1005308. [PMID: 26588216 PMCID: PMC4654494 DOI: 10.1371/journal.ppat.1005308] [Citation(s) in RCA: 61] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2015] [Accepted: 11/03/2015] [Indexed: 01/10/2023] Open
Abstract
The microbiome shapes diverse facets of human biology and disease, with the importance of fungi only beginning to be appreciated. Microbial communities infiltrate diverse anatomical sites as with the respiratory tract of healthy humans and those with diseases such as cystic fibrosis, where chronic colonization and infection lead to clinical decline. Although fungi are frequently recovered from cystic fibrosis patient sputum samples and have been associated with deterioration of lung function, understanding of species and population dynamics remains in its infancy. Here, we coupled high-throughput sequencing of the ribosomal RNA internal transcribed spacer 1 (ITS1) with phenotypic and genotypic analyses of fungi from 89 sputum samples from 28 cystic fibrosis patients. Fungal communities defined by sequencing were concordant with those defined by culture-based analyses of 1,603 isolates from the same samples. Different patients harbored distinct fungal communities. There were detectable trends, however, including colonization with Candida and Aspergillus species, which was not perturbed by clinical exacerbation or treatment. We identified considerable inter- and intra-species phenotypic variation in traits important for host adaptation, including antifungal drug resistance and morphogenesis. While variation in drug resistance was largely between species, striking variation in morphogenesis emerged within Candida species. Filamentation was uncoupled from inducing cues in 28 Candida isolates recovered from six patients. The filamentous isolates were resistant to the filamentation-repressive effects of Pseudomonas aeruginosa, implicating inter-kingdom interactions as the selective force. Genome sequencing revealed that all but one of the filamentous isolates harbored mutations in the transcriptional repressor NRG1; such mutations were necessary and sufficient for the filamentous phenotype. Six independent nrg1 mutations arose in Candida isolates from different patients, providing a poignant example of parallel evolution. Together, this combined clinical-genomic approach provides a high-resolution portrait of the fungal microbiome of cystic fibrosis patient lungs and identifies a genetic basis of pathogen adaptation. Microbial cells vastly outnumber human cells in our bodies, yet we are only beginning to understand how these microbes influence human health and disease. One disease for which microbial communities are especially important is cystic fibrosis, where persistent lung infections can be lethal. Fungi are associated with poor respiratory function, but how fungal communities change with disease progression or treatment remains enigmatic. Here, we assess the dynamics of fungal communities by combining high-throughput sequencing of sputum samples from 28 patients with detailed analysis of phenotypes and genotypes of 1,603 fungal isolates. We found stable communities dominated by Candida and Aspergillus, and diversity in traits important for host adaptation. Antifungal drug resistance varied largely between species, while morphogenesis varied within species. For Candida species, the capacity to transition between yeast and filaments is a key virulence trait that is normally regulated by inducing cues, however, 28 isolates grew as filaments without such cues. Filamentation was due to loss-of-function mutations in the transcriptional regulator NRG1 in most isolates, which conferred resistance to the filament-repressive effects of a common bacterial pathogen. This work provides a portrait of the fungal microbiome associated with a lethal disease, and illuminates a genetic basis of pathogen adaptation.
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Affiliation(s)
- Sang Hu Kim
- Department of Molecular Genetics, University of Toronto, Toronto, Ontario, Canada
| | - Shawn T. Clark
- Department of Laboratory Medicine and Pathobiology, University of Toronto, Toronto, Ontario, Canada
| | - Anuradha Surendra
- Centre for the Analysis of Genome Evolution & Function, University of Toronto, Toronto, Ontario, Canada
| | - Julia K. Copeland
- Centre for the Analysis of Genome Evolution & Function, University of Toronto, Toronto, Ontario, Canada
| | - Pauline W. Wang
- Centre for the Analysis of Genome Evolution & Function, University of Toronto, Toronto, Ontario, Canada
- Department of Cell & Systems Biology, University of Toronto, Toronto, Ontario, Canada
| | - Ron Ammar
- Donnelly Centre for Cellular and Biomolecular Research, University of Toronto, Toronto, Ontario, Canada
| | - Cathy Collins
- Department of Molecular Genetics, University of Toronto, Toronto, Ontario, Canada
| | | | - Corey Nislow
- Faculty of Pharmaceutical Sciences, The University of British Columbia, Vancouver, British Columbia, Canada
| | - David M. Hwang
- Department of Laboratory Medicine and Pathobiology, University of Toronto, Toronto, Ontario, Canada
| | - David S. Guttman
- Centre for the Analysis of Genome Evolution & Function, University of Toronto, Toronto, Ontario, Canada
- Department of Cell & Systems Biology, University of Toronto, Toronto, Ontario, Canada
| | - Leah E. Cowen
- Department of Molecular Genetics, University of Toronto, Toronto, Ontario, Canada
- * E-mail:
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90
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Large-Scale Analysis of Kinase Signaling in Yeast Pseudohyphal Development Identifies Regulation of Ribonucleoprotein Granules. PLoS Genet 2015; 11:e1005564. [PMID: 26447709 PMCID: PMC4598065 DOI: 10.1371/journal.pgen.1005564] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2015] [Accepted: 09/10/2015] [Indexed: 01/10/2023] Open
Abstract
Yeast pseudohyphal filamentation is a stress-responsive growth transition relevant to processes required for virulence in pathogenic fungi. Pseudohyphal growth is controlled through a regulatory network encompassing conserved MAPK (Ste20p, Ste11p, Ste7p, Kss1p, and Fus3p), protein kinase A (Tpk2p), Elm1p, and Snf1p kinase pathways; however, the scope of these pathways is not fully understood. Here, we implemented quantitative phosphoproteomics to identify each of these signaling networks, generating a kinase-dead mutant in filamentous S. cerevisiae and surveying for differential phosphorylation. By this approach, we identified 439 phosphoproteins dependent upon pseudohyphal growth kinases. We report novel phosphorylation sites in 543 peptides, including phosphorylated residues in Ras2p and Flo8p required for wild-type filamentous growth. Phosphoproteins in these kinase signaling networks were enriched for ribonucleoprotein (RNP) granule components, and we observe co-localization of Kss1p, Fus3p, Ste20p, and Tpk2p with the RNP component Igo1p. These kinases localize in puncta with GFP-visualized mRNA, and KSS1 is required for wild-type levels of mRNA localization in RNPs. Kss1p pathway activity is reduced in lsm1Δ/Δ and pat1Δ/Δ strains, and these genes encoding P-body proteins are epistatic to STE7. The P-body protein Dhh1p is also required for hyphal development in Candida albicans. Collectively, this study presents a wealth of data identifying the yeast phosphoproteome in pseudohyphal growth and regulatory interrelationships between pseudohyphal growth kinases and RNPs. Eukaryotic cells affect precise changes in shape and growth in response to environmental and nutritional stress, enabling cell survival and wild-type function. The single-celled budding yeast provides a striking example, undergoing a set of changes under conditions of nitrogen or glucose limitation resulting in the formation of extended cellular chains or filaments. Related filamentous growth transitions are required for virulence in pathogenic fungi and have been studied extensively; however, the full scope of signaling underlying the filamentous growth transition remains to be determined. Here, we used a combination of genetics and proteomics to identify proteins that undergo phosphorylation dependent upon kinases required for filamentous growth. Within this protein set, we identified novel sites of phosphorylation in the yeast proteome and extensive phosphorylation of mRNA-protein complexes regulating mRNA decay and translation. The data indicate an interrelationship between filamentous growth and these ubiquitously conserved sites of RNA regulation: the RNA-protein complexes are required for the filamentous growth transition, and a well studied filamentous growth signaling kinase is required for wild-type numbers of RNA-protein complexes. This interdependence is previously unappreciated, highlighting an additional level of translational control underlying this complex growth transition.
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91
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Chen Y, Zhai S, Sun Y, Li M, Dong Y, Wang X, Zhang H, Zheng X, Wang P, Zhang Z. MoTup1 is required for growth, conidiogenesis and pathogenicity of Magnaporthe oryzae. MOLECULAR PLANT PATHOLOGY 2015; 16:799-810. [PMID: 25583028 PMCID: PMC6638498 DOI: 10.1111/mpp.12235] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/05/2023]
Abstract
The general transcriptional repressor Tup1 proteins play important regulatory roles in the growth and development of fungi. In this report, we characterized MoTup1, a protein homologous to Tup1 of Saccharomyces cerevisiae, from M. oryzae. Disruption of MoTUP1 resulted in severe mycelial growth reduction and a defect in conidiogenesis. We found that MoTup1 is required for the maintenance of cell wall integrity by regulating the expression of the genes involved in cell wall biosynthesis. Pathogenicity assays indicated that the ΔMotup1 mutants lost the ability to invade both rice and barley hosts. Moreover, observation of rice epidermis penetration showed that the hyphal tips of the mutants could still form appressorium-like structures, but were unable to invade host cells. Taken together, our results demonstrate that M. oryzae MoTup1 is an important regulatory factor in fungal growth, development and pathogenesis on hosts.
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Affiliation(s)
- Yue Chen
- Department of Plant Pathology, College of Plant Protection, Nanjing Agricultural University, Nanjing, 210095, China
- Key Laboratory of Integrated Management of Crop Diseases and Pests, Ministry of Education, Nanjing, 210095, China
| | - Su Zhai
- Department of Plant Pathology, College of Plant Protection, Nanjing Agricultural University, Nanjing, 210095, China
- Key Laboratory of Integrated Management of Crop Diseases and Pests, Ministry of Education, Nanjing, 210095, China
| | - Yi Sun
- Department of Plant Pathology, College of Plant Protection, Nanjing Agricultural University, Nanjing, 210095, China
- Key Laboratory of Integrated Management of Crop Diseases and Pests, Ministry of Education, Nanjing, 210095, China
| | - Mengying Li
- Department of Plant Pathology, College of Plant Protection, Nanjing Agricultural University, Nanjing, 210095, China
- Key Laboratory of Integrated Management of Crop Diseases and Pests, Ministry of Education, Nanjing, 210095, China
| | - Yanhan Dong
- Department of Plant Pathology, College of Plant Protection, Nanjing Agricultural University, Nanjing, 210095, China
- Key Laboratory of Integrated Management of Crop Diseases and Pests, Ministry of Education, Nanjing, 210095, China
| | - Xiaoli Wang
- Department of Plant Pathology, College of Plant Protection, Nanjing Agricultural University, Nanjing, 210095, China
- Key Laboratory of Integrated Management of Crop Diseases and Pests, Ministry of Education, Nanjing, 210095, China
| | - Haifeng Zhang
- Department of Plant Pathology, College of Plant Protection, Nanjing Agricultural University, Nanjing, 210095, China
- Key Laboratory of Integrated Management of Crop Diseases and Pests, Ministry of Education, Nanjing, 210095, China
| | - Xiaobo Zheng
- Department of Plant Pathology, College of Plant Protection, Nanjing Agricultural University, Nanjing, 210095, China
- Key Laboratory of Integrated Management of Crop Diseases and Pests, Ministry of Education, Nanjing, 210095, China
| | - Ping Wang
- Department of Pediatrics and the Research Institute for Children, Louisiana State University Health Sciences Center, New Orleans, LA, 70118, USA
| | - Zhengguang Zhang
- Department of Plant Pathology, College of Plant Protection, Nanjing Agricultural University, Nanjing, 210095, China
- Key Laboratory of Integrated Management of Crop Diseases and Pests, Ministry of Education, Nanjing, 210095, China
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92
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Functional Divergence of Hsp90 Genetic Interactions in Biofilm and Planktonic Cellular States. PLoS One 2015; 10:e0137947. [PMID: 26367740 PMCID: PMC4569550 DOI: 10.1371/journal.pone.0137947] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2015] [Accepted: 08/24/2015] [Indexed: 01/23/2023] Open
Abstract
Candida albicans is among the most prevalent opportunistic fungal pathogens. Its capacity to cause life-threatening bloodstream infections is associated with the ability to form biofilms, which are intrinsically drug resistant reservoirs for dispersal. A key regulator of biofilm drug resistance and dispersal is the molecular chaperone Hsp90, which stabilizes many signal transducers. We previously identified 226 C. albicans Hsp90 genetic interactors under planktonic conditions, of which 56 are involved in transcriptional regulation. Six of these transcriptional regulators have previously been implicated in biofilm formation, suggesting that Hsp90 genetic interactions identified in planktonic conditions may have functional significance in biofilms. Here, we explored the relationship between Hsp90 and five of these transcription factor genetic interactors: BCR1, MIG1, TEC1, TUP1, and UPC2. We deleted each transcription factor gene in an Hsp90 conditional expression strain, and assessed biofilm formation and morphogenesis. Strikingly, depletion of Hsp90 conferred no additional biofilm defect in the mutants. An interaction was observed in which deletion of BCR1 enhanced filamentation upon reduction of Hsp90 levels. Further, although Hsp90 modulates expression of TEC1, TUP1, and UPC2 in planktonic conditions, it has no impact in biofilms. Lastly, we probed for physical interactions between Hsp90 and Tup1, whose WD40 domain suggests that it might interact with Hsp90 directly. Hsp90 and Tup1 formed a stable complex, independent of temperature or developmental state. Our results illuminate a physical interaction between Hsp90 and a key transcriptional regulator of filamentation and biofilm formation, and suggest that Hsp90 has distinct genetic interactions in planktonic and biofilm cellular states.
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93
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A Gβ protein and the TupA Co-Regulator Bind to Protein Kinase A Tpk2 to Act as Antagonistic Molecular Switches of Fungal Morphological Changes. PLoS One 2015; 10:e0136866. [PMID: 26334875 PMCID: PMC4559445 DOI: 10.1371/journal.pone.0136866] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2015] [Accepted: 08/09/2015] [Indexed: 11/19/2022] Open
Abstract
The human pathogenic fungus Paracoccidioides brasiliensis (Pb) undergoes a morphological transition from a saprobic mycelium to pathogenic yeast that is controlled by the cAMP-signaling pathway. There is a change in the expression of the Gβ-protein PbGpb1, which interacts with adenylate cyclase, during this morphological transition. We exploited the fact that the cAMP-signaling pathway of Saccharomyces cerevisiae does not include a Gβ-protein to probe the functional role of PbGpb1. We present data that indicates that PbGpb1 and the transcriptional regulator PbTupA both bind to the PKA protein PbTpk2. PbTPK2 was able to complement a TPK2Δ strain of S. cerevisiae, XPY5a/α, which was defective in pseudohyphal growth. Whilst PbGPB1 had no effect on the parent S. cerevisiae strain, MLY61a/α, it repressed the filamentous growth of XPY5a/α transformed with PbTPK2, behaviour that correlated with a reduced expression of the floculin FLO11. In vitro, PbGpb1 reduced the kinase activity of PbTpk2, suggesting that inhibition of PbTpk2 by PbGpb1 reduces the level of expression of Flo11, antagonizing the filamentous growth of the cells. In contrast, expressing the co-regulator PbTUPA in XPY5a/α cells transformed with PbTPK2, but not untransformed cells, induced hyperfilamentous growth, which could be antagonized by co-transforming the cells with PbGPB1. PbTUPA was unable to induce the hyperfilamentous growth of a FLO8Δ strain, suggesting that PbTupA functions in conjunction with the transcription factor Flo8 to control Flo11 expression. Our data indicates that P. brasiliensis PbGpb1 and PbTupA, both of which have WD/β-propeller structures, bind to PbTpk2 to act as antagonistic molecular switches of cell morphology, with PbTupA and PbGpb1 inducing and repressing filamentous growth, respectively. Our findings define a potential mechanism for controlling the morphological switch that underpins the virulence of dimorphic fungi.
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94
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Mitochondrial Activity and Cyr1 Are Key Regulators of Ras1 Activation of C. albicans Virulence Pathways. PLoS Pathog 2015; 11:e1005133. [PMID: 26317337 PMCID: PMC4552728 DOI: 10.1371/journal.ppat.1005133] [Citation(s) in RCA: 81] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2015] [Accepted: 08/05/2015] [Indexed: 12/25/2022] Open
Abstract
Candida albicans is both a major fungal pathogen and a member of the commensal human microflora. The morphological switch from yeast to hyphal growth is associated with disease and many environmental factors are known to influence the yeast-to-hyphae switch. The Ras1-Cyr1-PKA pathway is a major regulator of C. albicans morphogenesis as well as biofilm formation and white-opaque switching. Previous studies have shown that hyphal growth is strongly repressed by mitochondrial inhibitors. Here, we show that mitochondrial inhibitors strongly decreased Ras1 GTP-binding and activity in C. albicans and similar effects were observed in other Candida species. Consistent with there being a connection between respiratory activity and GTP-Ras1 binding, mutants lacking complex I or complex IV grew as yeast in hypha-inducing conditions, had lower levels of GTP-Ras1, and Ras1 GTP-binding was unaffected by respiratory inhibitors. Mitochondria-perturbing agents decreased intracellular ATP concentrations and metabolomics analyses of cells grown with different respiratory inhibitors found consistent perturbation of pyruvate metabolism and the TCA cycle, changes in redox state, increased catabolism of lipids, and decreased sterol content which suggested increased AMP kinase activity. Biochemical and genetic experiments provide strong evidence for a model in which the activation of Ras1 is controlled by ATP levels in an AMP kinase independent manner. The Ras1 GTPase activating protein, Ira2, but not the Ras1 guanine nucleotide exchange factor, Cdc25, was required for the reduction of Ras1-GTP in response to inhibitor-mediated reduction of ATP levels. Furthermore, Cyr1, a well-characterized Ras1 effector, participated in the control of Ras1-GTP binding in response to decreased mitochondrial activity suggesting a revised model for Ras1 and Cyr1 signaling in which Cyr1 and Ras1 influence each other and, together with Ira2, seem to form a master-regulatory complex necessary to integrate different environmental and intracellular signals, including metabolic status, to decide the fate of cellular morphology. Candida albicans is a successful fungal commensal and pathogen of humans. It is a polymorphic organism and the ability to switch from yeast to hyphal growth is associated with the commensal-to-pathogen switch. Previous research identified the Ras1-cAMP-protein kinase A pathway as a key regulator of hyphal growth. Here, we report that mitochondrial activity plays a key role in Ras1 activation, as respiratory inhibition decreased Ras1 activity and Ras1-dependent filamentation. We found that intracellular ATP modulates Ras1 activity through a pathway involving the GTPase activating protein Ira2 and the adenylate cyclase Cyr1. Based on our data the canonical Ras1 signaling model in C. albicans needs to be restructured in such a way that Cyr1 is no longer placed downstream of Ras1 but rather in a major signaling node with Ras1 and Ira2. Our studies suggest that the energy status of the cell is the most important signal involved in the decision of C. albicans to undergo the yeast-to-hyphae switch or express genes associated with the hyphal morphology as low intracellular ATP or associated cues override several hypha-inducing signals. Future studies will show if this knowledge can be used to develop therapies that would favor benign host-Candida interactions by promoting low Ras1 activity.
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95
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MIG1 Regulates Resistance of Candida albicans against the Fungistatic Effect of Weak Organic Acids. EUKARYOTIC CELL 2015; 14:1054-61. [PMID: 26297702 DOI: 10.1128/ec.00129-15] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/12/2015] [Accepted: 08/13/2015] [Indexed: 12/15/2022]
Abstract
Candida albicans is the leading cause of fungal infections; but it is also a member of the human microbiome, an ecosystem of thousands of microbial species potentially influencing the outcome of host-fungal interactions. Accordingly, antibacterial therapy raises the risk of candidiasis, yet the underlying mechanism is currently not fully understood. We hypothesize the existence of bacterial metabolites that normally control C. albicans growth and of fungal resistance mechanisms against these metabolites. Among the most abundant microbiota-derived metabolites found on human mucosal surfaces are weak organic acids (WOAs), such as acetic, propionic, butyric, and lactic acid. Here, we used quantitative growth assays to investigate the dose-dependent fungistatic properties of WOAs on C. albicans growth and found inhibition of growth to occur at physiologically relevant concentrations and pH values. This effect was conserved across distantly related fungal species both inside and outside the CTG clade. We next screened a library of transcription factor mutants and identified several genes required for the resistance of C. albicans to one or more WOAs. A single gene, MIG1, previously known for its role in glucose repression, conferred resistance against all four acids tested. Consistent with glucose being an upstream activator of Mig1p, the presence of this carbon source was required for WOA resistance in wild-type C. albicans. Conversely, a MIG1-complemented strain completely restored the glucose-dependent resistance against WOAs. We conclude that Mig1p plays a central role in orchestrating a transcriptional program to fight against the fungistatic effect of this class of highly abundant metabolites produced by the gastrointestinal tract microbiota.
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96
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de Rossi BP, García C, Alcaraz E, Franco M. Stenotrophomonas maltophilia interferes via the DSF-mediated quorum sensing system with Candida albicans filamentation and its planktonic and biofilm modes of growth. Rev Argent Microbiol 2015; 46:288-97. [PMID: 25576410 DOI: 10.1016/s0325-7541(14)70084-7] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2014] [Accepted: 10/29/2014] [Indexed: 11/16/2022] Open
Abstract
Stenotrophomonas maltophilia is a nosocomial pathogen of increasing importance. S. maltophilia K279a genome encodes a diffusible signal factor (DSF) dependent quorum sensing (QS) system that was first identified in Xanthomonas campestris pv. campestris. DSF from X. campestris is a homologue of farnesoic acid, a Candida albicans QS signal which inhibits the yeast-to-hyphal shift. Here we describe the antagonistic effects of S. maltophilia on C. albicans on filamentation as well as on its planktonic and biofilm modes of growth. To determine the role of the DSF-mediated quorum sensing system in these effects, C. albicans ATCC 10231 and C. albicans tup1 mutant, locked in the filamentous form, were grown with K279a or with its rpfF deletion mutant (DSF-). A significant reduction in viable counts of C. albicans was observed in planktonic cocultures with K279a as well as in mixed biofilms. Furthermore, no viable cells of C. albicans tup1 were recovered from K279a mixed biofilms. Fungal viability was also assessed by labeling biofilms with SYTO 9 and propidium iodide. Confocal images showed that K279a can kill hyphae and also yeast cells. Light microscopic analysis showed that K279a severely affects hyphae integrity. On the other hand, the presence of K279a rpfF did not affect fungal morphology or viability. In conclusion, we report for the first time that S. maltophilia interferes with two key virulence factors of C. albicans, the yeast-to-hyphal transition and biofilm formation. DSF could be directly responsible for these effects or may induce the gene expression involved in antifungal activity.
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Affiliation(s)
- Beatriz Passerini de Rossi
- Cátedra de Microbiología, Facultad de Farmacia y Bioquímica, Universidad de Buenos Aires, Ciudad Autónoma de Buenos Aires, Argentina.
| | - Carlos García
- Cátedra de Microbiología, Facultad de Farmacia y Bioquímica, Universidad de Buenos Aires, Ciudad Autónoma de Buenos Aires, Argentina
| | - Eliana Alcaraz
- Cátedra de Microbiología, Facultad de Farmacia y Bioquímica, Universidad de Buenos Aires, Ciudad Autónoma de Buenos Aires, Argentina
| | - Mirta Franco
- Cátedra de Microbiología, Facultad de Farmacia y Bioquímica, Universidad de Buenos Aires, Ciudad Autónoma de Buenos Aires, Argentina
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97
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Childers DS, Kadosh D. Filament condition-specific response elements control the expression of NRG1 and UME6, key transcriptional regulators of morphology and virulence in Candida albicans. PLoS One 2015; 10:e0122775. [PMID: 25811669 PMCID: PMC4374957 DOI: 10.1371/journal.pone.0122775] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2014] [Accepted: 02/23/2015] [Indexed: 12/18/2022] Open
Abstract
Candida albicans is the most frequently isolated human fungal pathogen and can cause a range of mucosal and systemic infections in immunocompromised individuals. Morphogenesis, the ability to undergo a reversible transition from budding yeast to elongated filaments, is an essential virulence trait. The yeast-to-filament transition is associated with expression of genes specifically important for filamentation as well as other virulence-related processes, and is controlled, in part, by the key transcriptional regulators Nrg1 and Ume6. Both of these regulators are themselves controlled at the transcriptional level by filament-inducing environmental cues, although little is known about how this process occurs. In order to address this question and determine whether environmental signals regulate transcription of UME6 and NRG1 via distinct and/or common promoter elements, we performed promoter deletion analyses. Strains bearing promoter deletion constructs were induced to form filaments in YEPD plus 10% serum at 37°C, Spider medium (nitrogen and carbon starvation) and/or Lee’s medium pH 6.8 (neutral pH) and reporter gene expression was measured. In the NRG1 promoter we identified several distinct condition-specific response elements for YEPD plus 10% serum at 37°C and Spider medium. In the UME6 promoter we also identified response elements for YEPD plus 10% serum at 37°C. While a few of these elements are distinct, others overlap with those which respond to Lee’s pH 6.8 medium. Consistent with UME6 possessing a very long 5’ UTR, many response elements in the UME6 promoter are located significantly upstream from the coding sequence. Our data indicate that certain distinct condition-specific elements can control expression of C. albicans UME6 and NRG1 in response to key filament-inducing environmental cues. Because C. albicans encounters a variety of host microenvironments during infection, our results suggest that UME6 and NRG1 expression can be differentially modulated by multiple signaling pathways to control filamentation and virulence in vivo.
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Affiliation(s)
- Delma S. Childers
- Department of Microbiology and Immunology, University of Texas Health Science Center at San Antonio, San Antonio, United States of America
| | - David Kadosh
- Department of Microbiology and Immunology, University of Texas Health Science Center at San Antonio, San Antonio, United States of America
- * E-mail:
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98
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Abstract
Only few Candida species, e.g., Candida albicans, Candida glabrata, Candida dubliniensis, and Candida parapsilosis, are successful colonizers of a human host. Under certain circumstances these species can cause infections ranging from superficial to life-threatening disseminated candidiasis. The success of C. albicans, the most prevalent and best studied Candida species, as both commensal and human pathogen depends on its genetic, biochemical, and morphological flexibility which facilitates adaptation to a wide range of host niches. In addition, formation of biofilms provides additional protection from adverse environmental conditions. Furthermore, in many host niches Candida cells coexist with members of the human microbiome. The resulting fungal-bacterial interactions have a major influence on the success of C. albicans as commensal and also influence disease development and outcome. In this chapter, we review the current knowledge of important survival strategies of Candida spp., focusing on fundamental fitness and virulence traits of C. albicans.
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Affiliation(s)
- Melanie Polke
- Research Group Microbial Immunology, Hans-Knoell-Institute, Jena, Germany; Department Microbial Pathogenicity Mechanisms, Hans-Knoell-Institute, Jena, Germany
| | - Bernhard Hube
- Department Microbial Pathogenicity Mechanisms, Hans-Knoell-Institute, Jena, Germany; Friedrich-Schiller-University, Jena, Germany; Center for Sepsis Control and Care, Jena University Hospital, Jena, Germany
| | - Ilse D Jacobsen
- Research Group Microbial Immunology, Hans-Knoell-Institute, Jena, Germany; Friedrich-Schiller-University, Jena, Germany
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99
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Kashem SW, Igyarto BZ, Gerami-Nejad M, Kumamoto Y, Mohammed JA, Jarrett E, Drummond RA, Zurawski SM, Zurawski G, Berman J, Iwasaki A, Brown GD, Kaplan DH. Candida albicans morphology and dendritic cell subsets determine T helper cell differentiation. Immunity 2015; 42:356-366. [PMID: 25680275 DOI: 10.1016/j.immuni.2015.01.008] [Citation(s) in RCA: 163] [Impact Index Per Article: 18.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2014] [Revised: 12/03/2014] [Accepted: 01/22/2015] [Indexed: 02/07/2023]
Abstract
Candida albicans is a dimorphic fungus responsible for chronic mucocutaneous and systemic infections. Mucocutaneous immunity to C. albicans requires T helper 17 (Th17) cell differentiation that is thought to depend on recognition of filamentous C. albicans. Systemic immunity is considered T cell independent. Using a murine skin infection model, we compared T helper cell responses to yeast and filamentous C. albicans. We found that only yeast induced Th17 cell responses through a mechanism that required Dectin-1-mediated expression of interleukin-6 (IL-6) by Langerhans cells. Filamentous forms induced Th1 without Th17 cell responses due to the absence of Dectin-1 ligation. Notably, Th17 cell responses provided protection against cutaneous infection while Th1 cell responses provided protection against systemic infection. Thus, C. albicans morphology drives distinct T helper cell responses that provide tissue-specific protection. These findings provide insight into compartmentalization of Th cell responses and C. albicans pathogenesis and have critical implications for vaccine strategies.
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Affiliation(s)
- Sakeen W Kashem
- Department of Dermatology, Center for Immunology, University of Minnesota, Minneapolis, MN 55455, USA
| | - Botond Z Igyarto
- Department of Dermatology, Center for Immunology, University of Minnesota, Minneapolis, MN 55455, USA
| | - Maryam Gerami-Nejad
- Department of Molecular and Cellular Biology, University of Minnesota, Minneapolis, MN 55455, USA
| | - Yosuke Kumamoto
- Department of Immunobiology, Yale University School of Medicine, New Haven, CT 06520, USA
| | - Javed A Mohammed
- Department of Dermatology, Center for Immunology, University of Minnesota, Minneapolis, MN 55455, USA
| | - Elizabeth Jarrett
- Department of Dermatology, Center for Immunology, University of Minnesota, Minneapolis, MN 55455, USA
| | - Rebecca A Drummond
- Aberdeen Fungal Group, Institute of Medical Sciences, University of Aberdeen, Aberdeen, AB25 2ZD, UK
| | - Sandra M Zurawski
- Baylor Institute for Immunology Research and INSERM U899 - ANRS Center for Human Vaccines, 3434 Live Oak Street, Dallas, TX 75204
| | - Gerard Zurawski
- Baylor Institute for Immunology Research and INSERM U899 - ANRS Center for Human Vaccines, 3434 Live Oak Street, Dallas, TX 75204
| | - Judith Berman
- Department of Molecular and Cellular Biology, University of Minnesota, Minneapolis, MN 55455, USA.,Department of Molecular Microbiology and Biotechnology, George Wise Faculty of Life Sciences Tel Aviv University, Ramat Aviv, 69978 Israel
| | - Akiko Iwasaki
- Department of Immunobiology, Yale University School of Medicine, New Haven, CT 06520, USA
| | - Gordon D Brown
- Aberdeen Fungal Group, Institute of Medical Sciences, University of Aberdeen, Aberdeen, AB25 2ZD, UK
| | - Daniel H Kaplan
- Department of Dermatology, Center for Immunology, University of Minnesota, Minneapolis, MN 55455, USA
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100
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Pointer BR, Boyer MP, Schmidt M. Boric acid destabilizes the hyphal cytoskeleton and inhibits invasive growth ofCandida albicans. Yeast 2015; 32:389-98. [DOI: 10.1002/yea.3066] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2014] [Revised: 12/12/2014] [Accepted: 01/14/2015] [Indexed: 11/05/2022] Open
Affiliation(s)
| | - Michael P. Boyer
- Department of Biochemistry and Nutrition; Des Moines University; IA USA
| | - Martin Schmidt
- Department of Biochemistry and Nutrition; Des Moines University; IA USA
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