1
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Ping FLY, Vahsen T, Brault A, Néré R, Labbé S. The flavohemoglobin Yhb1 is a new interacting partner of the heme transporter Str3. Mol Microbiol 2024; 122:29-49. [PMID: 38778742 DOI: 10.1111/mmi.15281] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2024] [Revised: 05/03/2024] [Accepted: 05/10/2024] [Indexed: 05/25/2024]
Abstract
Nitric oxide (˙NO) is a free radical that induces nitrosative stress, which can jeopardize cell viability. Yeasts have evolved diverse detoxification mechanisms to effectively counteract ˙NO-mediated cytotoxicity. One mechanism relies on the flavohemoglobin Yhb1, whereas a second one requires the S-nitrosoglutathione reductase Fmd2. To investigate heme-dependent activation of Yhb1 in response to ˙NO, we use hem1Δ-derivative Schizosaccharomyces pombe strains lacking the initial enzyme in heme biosynthesis, forcing cells to assimilate heme from external sources. Under these conditions, yhb1+ mRNA levels are repressed in the presence of iron through a mechanism involving the GATA-type transcriptional repressor Fep1. In contrast, when iron levels are low, the transcription of yhb1+ is derepressed and further induced in the presence of the ˙NO donor DETANONOate. Cells lacking Yhb1 or expressing inactive forms of Yhb1 fail to grow in a hemin-dependent manner when exposed to DETANONOate. Similarly, the loss of function of the heme transporter Str3 phenocopies the effects of Yhb1 disruption by causing hypersensitivity to DETANONOate under hemin-dependent culture conditions. Coimmunoprecipitation and bimolecular fluorescence complementation assays demonstrate the interaction between Yhb1 and the heme transporter Str3. Collectively, our findings unveil a novel pathway for activating Yhb1, fortifying yeast cells against nitrosative stress.
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Affiliation(s)
- Florie Lo Ying Ping
- Département de Biochimie et de Génomique Fonctionnelle, Faculté de médecine et des sciences de la santé, Université de Sherbrooke, Sherbrooke, Qubec, Canada
| | - Tobias Vahsen
- Département de Biochimie et de Génomique Fonctionnelle, Faculté de médecine et des sciences de la santé, Université de Sherbrooke, Sherbrooke, Qubec, Canada
| | - Ariane Brault
- Département de Biochimie et de Génomique Fonctionnelle, Faculté de médecine et des sciences de la santé, Université de Sherbrooke, Sherbrooke, Qubec, Canada
| | - Raphaël Néré
- Département de Biochimie et de Génomique Fonctionnelle, Faculté de médecine et des sciences de la santé, Université de Sherbrooke, Sherbrooke, Qubec, Canada
| | - Simon Labbé
- Département de Biochimie et de Génomique Fonctionnelle, Faculté de médecine et des sciences de la santé, Université de Sherbrooke, Sherbrooke, Qubec, Canada
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2
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Zhang Y, Cai H, Chen R, Feng J. DNA Damage Checkpoints Govern Global Gene Transcription and Exhibit Species-Specific Regulation on HOF1 in Candida albicans. J Fungi (Basel) 2024; 10:387. [PMID: 38921373 PMCID: PMC11204775 DOI: 10.3390/jof10060387] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2024] [Revised: 05/25/2024] [Accepted: 05/27/2024] [Indexed: 06/27/2024] Open
Abstract
DNA damage checkpoints are essential for coordinating cell cycle arrest and gene transcription during DNA damage response. Exploring the targets of checkpoint kinases in Saccharomyces cerevisiae and other fungi has expanded our comprehension of the downstream pathways involved in DNA damage response. While the function of checkpoint kinases, specifically Rad53, is well documented in the fungal pathogen Candida albicans, their targets remain poorly understood. In this study, we explored the impact of deleting RAD53 on the global transcription profiles and observed alterations in genes associated with ribosome biogenesis, DNA replication, and cell cycle. However, the deletion of RAD53 only affected a limited number of known DNA damage-responsive genes, including MRV6 and HMX1. Unlike S. cerevisiae, the downregulation of HOF1 transcription in C. albicans under the influence of Methyl Methanesulfonate (MMS) did not depend on Dun1 but still relied on Rad53 and Rad9. In addition, the transcription factor Mcm1 was identified as a regulator of HOF1 transcription, with evidence of dynamic binding to its promoter region; however, this dynamic binding was interrupted following the deletion of RAD53. Furthermore, Rad53 was observed to directly interact with the promoter region of HOF1, thus suggesting a potential role in governing its transcription. Overall, checkpoints regulate global gene transcription in C. albicans and show species-specific regulation on HOF1; these discoveries improve our understanding of the signaling pathway related to checkpoints in this pathogen.
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Affiliation(s)
| | | | | | - Jinrong Feng
- Department of Pathogen Biology, School of Medicine, Nantong University, Nantong 226007, China; (Y.Z.); (H.C.); (R.C.)
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3
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Henry M, Khemiri I, Tebbji F, Abu-Helu R, Vincent AT, Sellam A. Manganese homeostasis modulates fungal virulence and stress tolerance in Candida albicans. mSphere 2024; 9:e0080423. [PMID: 38380913 PMCID: PMC10964418 DOI: 10.1128/msphere.00804-23] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2023] [Accepted: 01/31/2024] [Indexed: 02/22/2024] Open
Abstract
Due to the scarcity of transition metals within the human host, fungal pathogens have evolved sophisticated mechanisms to uptake and utilize these micronutrients at the infection interface. While considerable attention was turned to iron and copper acquisition mechanisms and their importance in fungal fitness, less was done regarding either the role of manganese (Mn) in infectious processes or the cellular mechanism by which fungal cells achieve their Mn-homeostasis. Here, we undertook transcriptional profiling in the pathogenic fungus Candida albicans experiencing both Mn starvation and excess to capture biological processes that are modulated by this metal. We uncovered that Mn scarcity influences diverse processes associated with fungal fitness including invasion of host cells and antifungal sensitivity. We show that Mn levels influence the abundance of iron and zinc emphasizing the complex crosstalk between metals. The deletion of SMF12, a member of Mn Nramp transporters, confirmed its contribution to Mn uptake. smf12 was unable to form hyphae and damage host cells and exhibited sensitivity to azoles. We found that the unfolded protein response (UPR), likely activated by decreased glycosylation under Mn limitation, was required to recover growth when cells were shifted from an Mn-starved to an Mn-repleted medium. RNA-seq profiling of cells exposed to Mn excess revealed that UPR was also activated. Furthermore, the UPR signaling axis Ire1-Hac1 was required to bypass Mn toxicity. Collectively, this study underscores the importance of Mn homeostasis in fungal virulence and comprehensively provides a portrait of biological functions that are modulated by Mn in a fungal pathogen. IMPORTANCE Transition metals such as manganese provide considerable functionality across biological systems as they are used as cofactors for many catalytic enzymes. The availability of manganese is very limited inside the human body. Consequently, pathogenic microbes have evolved sophisticated mechanisms to uptake this micronutrient inside the human host to sustain their growth and cause infections. Here, we undertook a comprehensive approach to understand how manganese availability impacts the biology of the prevalent fungal pathogen, Candida albicans. We uncovered that manganese homeostasis in this pathogen modulates different biological processes that are essential for host infection which underscores the value of targeting fungal manganese homeostasis for potential antifungal therapeutics development.
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Affiliation(s)
- Manon Henry
- Montreal Heart Institute/Institut de Cardiologie de Montréal, Université de Montréal, Montréal, Québec, Canada
- Department of Microbiology, Infectious Diseases and Immunology, Faculty of Medicine, Université de Montréal, Montréal, Québec, Canada
| | - Inès Khemiri
- Montreal Heart Institute/Institut de Cardiologie de Montréal, Université de Montréal, Montréal, Québec, Canada
- Department of Microbiology, Infectious Diseases and Immunology, Faculty of Medicine, Université de Montréal, Montréal, Québec, Canada
| | - Faiza Tebbji
- Montreal Heart Institute/Institut de Cardiologie de Montréal, Université de Montréal, Montréal, Québec, Canada
| | - Rasmi Abu-Helu
- Department of Medical Laboratory Sciences, Faculty of Health Professions, Al-Quds University, Jerusalem, Palestine
| | - Antony T. Vincent
- Department of Animal Sciences, Université Laval, Quebec City, Québec, Canada
| | - Adnane Sellam
- Montreal Heart Institute/Institut de Cardiologie de Montréal, Université de Montréal, Montréal, Québec, Canada
- Department of Microbiology, Infectious Diseases and Immunology, Faculty of Medicine, Université de Montréal, Montréal, Québec, Canada
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4
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Chaillot J, Mallick J, Sellam A. The transcription factor Ahr1 links cell size control to amino acid metabolism in the opportunistic yeast Candida albicans. Biochem Biophys Res Commun 2022; 616:63-69. [DOI: 10.1016/j.bbrc.2022.05.074] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2022] [Accepted: 05/21/2022] [Indexed: 11/17/2022]
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5
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Henry M, Burgain A, Tebbji F, Sellam A. Transcriptional Control of Hypoxic Hyphal Growth in the Fungal Pathogen Candida albicans. Front Cell Infect Microbiol 2022; 11:770478. [PMID: 35127551 PMCID: PMC8807691 DOI: 10.3389/fcimb.2021.770478] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2021] [Accepted: 10/26/2021] [Indexed: 12/18/2022] Open
Abstract
The ability of Candida albicans, an important human fungal pathogen, to develop filamentous forms is a crucial determinant for host invasion and virulence. While hypoxia is one of the predominant host cues that promote C. albicans filamentous growth, the regulatory circuits that link oxygen availability to filamentation remain poorly characterized. We have undertaken a genetic screen and identified the two transcription factors Ahr1 and Tye7 as central regulators of the hypoxic filamentation. Both ahr1 and tye7 mutants exhibited a hyperfilamentous phenotype specifically under an oxygen-depleted environment suggesting that these transcription factors act as negative regulators of hypoxic filamentation. By combining microarray and ChIP-chip analyses, we have characterized the set of genes that are directly modulated by Ahr1 and Tye7. We found that both Ahr1 and Tye7 modulate a distinct set of genes and biological processes. Our genetic epistasis analysis supports our genomic finding and suggests that Ahr1 and Tye7 act independently to modulate hyphal growth in response to hypoxia. Furthermore, our genetic interaction experiments uncovered that Ahr1 and Tye7 repress the hypoxic filamentation via the Efg1 and Ras1/Cyr1 pathways, respectively. This study yielded a new and an unprecedented insight into the oxygen-sensitive regulatory circuit that control morphogenesis in a fungal pathogen.
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Affiliation(s)
- Manon Henry
- Montreal Heart Institute, Université de Montréal, Montréal, QC, Canada
| | - Anaïs Burgain
- Department of Microbiology, Infectious Diseases and Immunology, Faculty of Medicine, Université Laval, Quebec City, QC, Canada
| | - Faiza Tebbji
- Montreal Heart Institute, Université de Montréal, Montréal, QC, Canada
| | - Adnane Sellam
- Montreal Heart Institute, Université de Montréal, Montréal, QC, Canada
- Department of Microbiology, Infectious Diseases and Immunology, Faculty of Medicine, Université de Montréal, Montréal, QC, Canada
- *Correspondence: Adnane Sellam,
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6
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Guan G, Tao L, Yue H, Liang W, Gong J, Bing J, Zheng Q, Veri AO, Fan S, Robbins N, Cowen LE, Huang G. Environment-induced same-sex mating in the yeast Candida albicans through the Hsf1-Hsp90 pathway. PLoS Biol 2019; 17:e2006966. [PMID: 30865631 PMCID: PMC6415874 DOI: 10.1371/journal.pbio.2006966] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2018] [Accepted: 02/13/2019] [Indexed: 12/14/2022] Open
Abstract
While sexual reproduction is pervasive in eukaryotic cells, the strategies employed by fungal species to achieve and complete sexual cycles is highly diverse and complex. Many fungi, including Saccharomyces cerevisiae and Schizosaccharomyces pombe, are homothallic (able to mate with their own mitotic descendants) because of homothallic switching (HO) endonuclease-mediated mating-type switching. Under laboratory conditions, the human fungal pathogen Candida albicans can undergo both heterothallic and homothallic (opposite- and same-sex) mating. However, both mating modes require the presence of cells with two opposite mating types (MTLa/a and α/α) in close proximity. Given the predominant clonal feature of this yeast in the human host, both opposite- and same-sex mating would be rare in nature. In this study, we report that glucose starvation and oxidative stress, common environmental stresses encountered by the pathogen, induce the development of mating projections and efficiently permit same-sex mating in C. albicans with an "a" mating type (MTLa/a). This induction bypasses the requirement for the presence of cells with an opposite mating type and allows efficient sexual mating between cells derived from a single progenitor. Glucose starvation causes an increase in intracellular oxidative species, overwhelming the Heat Shock transcription Factor 1 (Hsf1)- and Heat shock protein (Hsp)90-mediated stress-response pathway. We further demonstrate that Candida TransActivating protein 4 (Cta4) and Cell Wall Transcription factor 1 (Cwt1), downstream effectors of the Hsf1-Hsp90 pathway, regulate same-sex mating in C. albicans through the transcriptional control of the master regulator of a-type mating, MTLa2, and the pheromone precursor-encoding gene Mating α factor precursor (MFα). Our results suggest that mating could occur much more frequently in nature than was originally appreciated and that same-sex mating could be an important mode of sexual reproduction in C. albicans.
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Affiliation(s)
- Guobo Guan
- State Key Laboratory of Mycology, Institute of Microbiology, Chinese Academy of Sciences, Beijing, China.,University of Chinese Academy of Sciences, Beijing, China
| | - Li Tao
- State Key Laboratory of Genetic Engineering, School of Life Sciences, Fudan University, Shanghai, China
| | - Huizhen Yue
- State Key Laboratory of Mycology, Institute of Microbiology, Chinese Academy of Sciences, Beijing, China.,University of Chinese Academy of Sciences, Beijing, China
| | - Weihong Liang
- State Key Laboratory of Mycology, Institute of Microbiology, Chinese Academy of Sciences, Beijing, China.,University of Chinese Academy of Sciences, Beijing, China
| | - Jiao Gong
- State Key Laboratory of Mycology, Institute of Microbiology, Chinese Academy of Sciences, Beijing, China.,University of Chinese Academy of Sciences, Beijing, China
| | - Jian Bing
- State Key Laboratory of Mycology, Institute of Microbiology, Chinese Academy of Sciences, Beijing, China
| | - Qiushi Zheng
- State Key Laboratory of Mycology, Institute of Microbiology, Chinese Academy of Sciences, Beijing, China.,University of Chinese Academy of Sciences, Beijing, China
| | - Amanda O Veri
- Department of Molecular Genetics, University of Toronto, Toronto, Ontario, Canada
| | - Shuru Fan
- State Key Laboratory of Mycology, Institute of Microbiology, Chinese Academy of Sciences, Beijing, China.,University of Chinese Academy of Sciences, Beijing, China
| | - Nicole Robbins
- Department of Molecular Genetics, University of Toronto, Toronto, Ontario, Canada
| | - Leah E Cowen
- Department of Molecular Genetics, University of Toronto, Toronto, Ontario, Canada
| | - Guanghua Huang
- State Key Laboratory of Mycology, Institute of Microbiology, Chinese Academy of Sciences, Beijing, China.,University of Chinese Academy of Sciences, Beijing, China.,State Key Laboratory of Genetic Engineering, School of Life Sciences, Fudan University, Shanghai, China
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7
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Sellam A, Chaillot J, Mallick J, Tebbji F, Richard Albert J, Cook MA, Tyers M. The p38/HOG stress-activated protein kinase network couples growth to division in Candida albicans. PLoS Genet 2019; 15:e1008052. [PMID: 30921326 PMCID: PMC6456229 DOI: 10.1371/journal.pgen.1008052] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/2019] [Revised: 04/09/2019] [Accepted: 02/28/2019] [Indexed: 12/26/2022] Open
Abstract
Cell size is a complex trait that responds to developmental and environmental cues. Quantitative size analysis of mutant strain collections disrupted for protein kinases and transcriptional regulators in the pathogenic yeast Candida albicans uncovered 66 genes that altered cell size, few of which overlapped with known size genes in the budding yeast Saccharomyces cerevisiae. A potent size regulator specific to C. albicans was the conserved p38/HOG MAPK module that mediates the osmostress response. Basal HOG activity inhibited the SBF G1/S transcription factor complex in a stress-independent fashion to delay the G1/S transition. The HOG network also governed ribosome biogenesis through the master transcriptional regulator Sfp1. Hog1 bound to the promoters and cognate transcription factors for ribosome biogenesis regulons and interacted genetically with the SBF G1/S machinery, and thereby directly linked cell growth and division. These results illuminate the evolutionary plasticity of size control and identify the HOG module as a nexus of cell cycle and growth regulation.
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Affiliation(s)
- Adnane Sellam
- Infectious Diseases Research Centre (CRI), CHU de Québec Research Center (CHUQ), Université Laval, Quebec City, QC, Canada
- Department of Microbiology, Infectious Disease and Immunology, Faculty of Medicine, Université Laval, Quebec City, QC, Canada
| | - Julien Chaillot
- Infectious Diseases Research Centre (CRI), CHU de Québec Research Center (CHUQ), Université Laval, Quebec City, QC, Canada
| | - Jaideep Mallick
- Institute for Research in Immunology and Cancer (IRIC), Department of Medicine, Université de Montréal, Montréal, Québec, Canada
| | - Faiza Tebbji
- Infectious Diseases Research Centre (CRI), CHU de Québec Research Center (CHUQ), Université Laval, Quebec City, QC, Canada
| | - Julien Richard Albert
- Department of Medical Genetics, University of British Columbia, Vancouver, British Columbia, Canada
| | - Michael A. Cook
- Centre for Systems Biology, Lunenfeld-Tanenbaum Research Institute, Mount Sinai Hospital, Toronto, Canada
| | - Mike Tyers
- Institute for Research in Immunology and Cancer (IRIC), Department of Medicine, Université de Montréal, Montréal, Québec, Canada
- Centre for Systems Biology, Lunenfeld-Tanenbaum Research Institute, Mount Sinai Hospital, Toronto, Canada
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8
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Integration of Growth and Cell Size via the TOR Pathway and the Dot6 Transcription Factor in Candida albicans. Genetics 2018; 211:637-650. [PMID: 30593490 DOI: 10.1534/genetics.118.301872] [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] [Received: 08/08/2018] [Accepted: 12/21/2018] [Indexed: 12/12/2022] Open
Abstract
In most species, size homeostasis appears to be exerted in late G1 phase as cells commit to division, called Start in yeast and the Restriction Point in metazoans. This size threshold couples cell growth to division, and, thereby, establishes long-term size homeostasis. Our former investigations have shown that hundreds of genes markedly altered cell size under homeostatic growth conditions in the opportunistic yeast Candida albicans, but surprisingly only few of these overlapped with size control genes in the budding yeast Saccharomyces cerevisiae Here, we investigated one of the divergent potent size regulators in C. albicans, the Myb-like HTH transcription factor Dot6. Our data demonstrated that Dot6 is a negative regulator of Start, and also acts as a transcriptional activator of ribosome biogenesis (Ribi) genes. Genetic epistasis uncovered that Dot6 interacted with the master transcriptional regulator of the G1 machinery, SBF complex, but not with the Ribi and cell size regulators Sch9, Sfp1, and p38/Hog1. Dot6 was required for carbon-source modulation of cell size, and it is regulated at the level of nuclear localization by the TOR pathway. Our findings support a model where Dot6 acts as a hub that integrates growth cues directly via the TOR pathway to control the commitment to mitotic division at G1.
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9
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Veri AO, Miao Z, Shapiro RS, Tebbji F, O’Meara TR, Kim SH, Colazo J, Tan K, Vyas VK, Whiteway M, Robbins N, Wong KH, Cowen LE. Tuning Hsf1 levels drives distinct fungal morphogenetic programs with depletion impairing Hsp90 function and overexpression expanding the target space. PLoS Genet 2018; 14:e1007270. [PMID: 29590106 PMCID: PMC5873724 DOI: 10.1371/journal.pgen.1007270] [Citation(s) in RCA: 35] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2017] [Accepted: 02/22/2018] [Indexed: 12/24/2022] Open
Abstract
The capacity to respond to temperature fluctuations is critical for microorganisms to survive within mammalian hosts, and temperature modulates virulence traits of diverse pathogens. One key temperature-dependent virulence trait of the fungal pathogen Candida albicans is its ability to transition from yeast to filamentous growth, which is induced by environmental cues at host physiological temperature. A key regulator of temperature-dependent morphogenesis is the molecular chaperone Hsp90, which has complex functional relationships with the transcription factor Hsf1. Although Hsf1 controls global transcriptional remodeling in response to heat shock, its impact on morphogenesis remains unknown. Here, we establish an intriguing paradigm whereby overexpression or depletion of C. albicans HSF1 induces morphogenesis in the absence of external cues. HSF1 depletion compromises Hsp90 function, thereby driving filamentation. HSF1 overexpression does not impact Hsp90 function, but rather induces a dose-dependent expansion of Hsf1 direct targets that drives overexpression of positive regulators of filamentation, including Brg1 and Ume6, thereby bypassing the requirement for elevated temperature during morphogenesis. This work provides new insight into Hsf1-mediated environmentally contingent transcriptional control, implicates Hsf1 in regulation of a key virulence trait, and highlights fascinating biology whereby either overexpression or depletion of a single cellular regulator induces a profound developmental transition. For human pathogens, the capacity to respond to elevated temperature is required for survival, with elevated temperature in the form of fever as a conserved host response to defend against infection. One of the leading fungal pathogens of humans in Candida albicans, which is capable of growing in both a yeast and filamentous state. The ability to transition between these forms is a key virulence trait, and one that is highly temperature-dependent. A pivotal regulator of filamentous growth is the temperature-responsive molecular chaperone Hsp90, which has complex relationships with the transcription factor Hsf1. Although Hsf1 regulates changes in gene expression in response to heat shock, its impact on morphogenesis remains unknown. Here, we uncover an intriguing phenomenon whereby overexpression or depletion of C. albicans HSF1 induces morphogenesis. We observe that HSF1 depletion compromises Hsp90 function, thereby driving filamentation. In contrast, HSF1 overexpression induces a dose-dependent expansion of its transcriptional targets that drives overexpression of positive regulators of filamentous growth. This work illuminates novel mechanisms through which tuning the levels of an environmentally contingent transcription factor drives a key developmental program.
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Affiliation(s)
- Amanda O. Veri
- Department of Molecular Genetics, University of Toronto, Toronto, Ontario, Canada
| | - Zhengqiang Miao
- Faculty of Health Sciences, University of Macau, Macau SAR, China
| | - Rebecca S. Shapiro
- Department of Molecular and Cellular Biology, University of Guelph, Guelph, Ontario, Canada
| | - Faiza Tebbji
- Infectious Disease Research Centre, Université Laval, Quebec City, Quebec, Canada
| | - Teresa R. O’Meara
- Department of Molecular Genetics, University of Toronto, Toronto, Ontario, Canada
| | - Sang Hu Kim
- Department of Molecular Genetics, University of Toronto, Toronto, Ontario, Canada
| | - Juan Colazo
- Vanderbilt University School of Medicine, Nashville, Tennessee, United States of America
| | - Kaeling Tan
- Faculty of Health Sciences, University of Macau, Macau SAR, China
| | - Valmik K. Vyas
- Whitehead Institute for Biomedical Research, Cambridge, Massachusetts, United States of America
| | - Malcolm Whiteway
- Department of Biology, Concordia University, Montréal, Quebec, Canada
| | - Nicole Robbins
- Department of Molecular Genetics, University of Toronto, Toronto, Ontario, Canada
| | - Koon Ho Wong
- Faculty of Health Sciences, University of Macau, Macau SAR, China
| | - Leah E. Cowen
- Department of Molecular Genetics, University of Toronto, Toronto, Ontario, Canada
- * E-mail:
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10
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Danhof HA, Vylkova S, Vesely EM, Ford AE, Gonzalez-Garay M, Lorenz MC. Robust Extracellular pH Modulation by Candida albicans during Growth in Carboxylic Acids. mBio 2016; 7:e01646-16. [PMID: 27935835 PMCID: PMC5111404 DOI: 10.1128/mbio.01646-16] [Citation(s) in RCA: 44] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2016] [Accepted: 10/24/2016] [Indexed: 12/25/2022] Open
Abstract
The opportunistic fungal pathogen Candida albicans thrives within diverse niches in the mammalian host. Among the adaptations that underlie this fitness is an ability to utilize a wide array of nutrients, especially sources of carbon that are disfavored by many other fungi; this contributes to its ability to survive interactions with the phagocytes that serve as key barriers against disseminated infections. We have reported that C. albicans generates ammonia as a byproduct of amino acid catabolism to neutralize the acidic phagolysosome and promote hyphal morphogenesis in a manner dependent on the Stp2 transcription factor. Here, we report that this species rapidly neutralizes acidic environments when utilizing carboxylic acids like pyruvate, α-ketoglutarate (αKG), or lactate as the primary carbon source. Unlike in cells growing in amino acid-rich medium, this does not result in ammonia release, does not induce hyphal differentiation, and is genetically distinct. While transcript profiling revealed significant similarities in gene expression in cells grown on either carboxylic or amino acids, genetic screens for mutants that fail to neutralize αKG medium identified a nonoverlapping set of genes, including CWT1, encoding a transcription factor responsive to cell wall and nitrosative stresses. Strains lacking CWT1 exhibit retarded αKG-mediated neutralization in vitro, exist in a more acidic phagolysosome, and are more susceptible to macrophage killing, while double cwt1Δ stp2Δ mutants are more impaired than either single mutant. Together, our observations indicate that C. albicans has evolved multiple ways to modulate the pH of host-relevant environments to promote its fitness as a pathogen. IMPORTANCE The fungal pathogen Candida albicans is a ubiquitous and usually benign constituent of the human microbial ecosystem. In individuals with weakened immune systems, this organism can cause potentially life-threatening infections and is one of the most common causes of hospital-acquired infections. Understanding the interactions between C. albicans and immune phagocytic cells, such as macrophages and neutrophils, will define the mechanisms of pathogenesis in this species. One such adaptation is an ability to make use of nonstandard nutrients that we predict are plentiful in certain niches within the host, including within these phagocytic cells. We show here that the metabolism of certain organic acids enables C. albicans to neutralize acidic environments, such as those within macrophages. This phenomenon is distinct in several significant ways from previous reports of similar processes, indicating that C. albicans has evolved multiple mechanisms to combat the harmful acidity of phagocytic cells.
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Affiliation(s)
- Heather A Danhof
- Department of Microbiology and Molecular Genetics, McGovern Medical School, University of Texas Health Science Center at Houston, Houston, Texas, USA
- The Graduate School of Biomedical Sciences, University of Texas Health Science Center at Houston, Houston, Texas, USA
| | - Slavena Vylkova
- Department of Microbiology and Molecular Genetics, McGovern Medical School, University of Texas Health Science Center at Houston, Houston, Texas, USA
| | - Elisa M Vesely
- Department of Microbiology and Molecular Genetics, McGovern Medical School, University of Texas Health Science Center at Houston, Houston, Texas, USA
- The Graduate School of Biomedical Sciences, University of Texas Health Science Center at Houston, Houston, Texas, USA
| | - Amy E Ford
- Department of Microbiology and Molecular Genetics, McGovern Medical School, University of Texas Health Science Center at Houston, Houston, Texas, USA
- The Graduate School of Biomedical Sciences, University of Texas Health Science Center at Houston, Houston, Texas, USA
| | - Manuel Gonzalez-Garay
- The Brown Foundation Institute for Molecular Medicine, University of Texas Health Science Center at Houston, Houston, Texas, USA
| | - Michael C Lorenz
- Department of Microbiology and Molecular Genetics, McGovern Medical School, University of Texas Health Science Center at Houston, Houston, Texas, USA
- The Graduate School of Biomedical Sciences, University of Texas Health Science Center at Houston, Houston, Texas, USA
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11
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Marcos CM, de Oliveira HC, de Melo WDCMA, da Silva JDF, Assato PA, Scorzoni L, Rossi SA, de Paula E Silva ACA, Mendes-Giannini MJS, Fusco-Almeida AM. Anti-Immune Strategies of Pathogenic Fungi. Front Cell Infect Microbiol 2016; 6:142. [PMID: 27896220 PMCID: PMC5108756 DOI: 10.3389/fcimb.2016.00142] [Citation(s) in RCA: 50] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2016] [Accepted: 10/13/2016] [Indexed: 12/24/2022] Open
Abstract
Pathogenic fungi have developed many strategies to evade the host immune system. Multiple escape mechanisms appear to function together to inhibit attack by the various stages of both the adaptive and the innate immune response. Thus, after entering the host, such pathogens fight to overcome the immune system to allow their survival, colonization and spread to different sites of infection. Consequently, the establishment of a successful infectious process is closely related to the ability of the pathogen to modulate attack by the immune system. Most strategies employed to subvert or exploit the immune system are shared among different species of fungi. In this review, we summarize the main strategies employed for immune evasion by some of the major pathogenic fungi.
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Affiliation(s)
- Caroline M Marcos
- Laboratório de Micologia Clínica, Departamento de Análises Clínicas, Faculdade de Ciências Farmacêuticas, Univ Estadual Paulista São Paulo, Brasil
| | - Haroldo C de Oliveira
- Laboratório de Micologia Clínica, Departamento de Análises Clínicas, Faculdade de Ciências Farmacêuticas, Univ Estadual Paulista São Paulo, Brasil
| | - Wanessa de Cássia M Antunes de Melo
- Laboratório de Micologia Clínica, Departamento de Análises Clínicas, Faculdade de Ciências Farmacêuticas, Univ Estadual Paulista São Paulo, Brasil
| | - Julhiany de Fátima da Silva
- Laboratório de Micologia Clínica, Departamento de Análises Clínicas, Faculdade de Ciências Farmacêuticas, Univ Estadual Paulista São Paulo, Brasil
| | - Patrícia A Assato
- Laboratório de Micologia Clínica, Departamento de Análises Clínicas, Faculdade de Ciências Farmacêuticas, Univ Estadual Paulista São Paulo, Brasil
| | - Liliana Scorzoni
- Laboratório de Micologia Clínica, Departamento de Análises Clínicas, Faculdade de Ciências Farmacêuticas, Univ Estadual Paulista São Paulo, Brasil
| | - Suélen A Rossi
- Laboratório de Micologia Clínica, Departamento de Análises Clínicas, Faculdade de Ciências Farmacêuticas, Univ Estadual Paulista São Paulo, Brasil
| | - Ana C A de Paula E Silva
- Laboratório de Micologia Clínica, Departamento de Análises Clínicas, Faculdade de Ciências Farmacêuticas, Univ Estadual Paulista São Paulo, Brasil
| | - Maria J S Mendes-Giannini
- Laboratório de Micologia Clínica, Departamento de Análises Clínicas, Faculdade de Ciências Farmacêuticas, Univ Estadual Paulista São Paulo, Brasil
| | - Ana M Fusco-Almeida
- Laboratório de Micologia Clínica, Departamento de Análises Clínicas, Faculdade de Ciências Farmacêuticas, Univ Estadual Paulista São Paulo, Brasil
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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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Endogenous nitric oxide accumulation is involved in the antifungal activity of Shikonin against Candida albicans. Emerg Microbes Infect 2016; 5:e88. [PMID: 27530748 PMCID: PMC5034102 DOI: 10.1038/emi.2016.87] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2015] [Revised: 03/16/2016] [Accepted: 03/22/2016] [Indexed: 12/28/2022]
Abstract
The aim of the present study was to investigate the role of nitric oxide (NO) in the antifungal activity of Shikonin (SK) against Candida albicans (C. albicans) and to clarify the underlying mechanism. The results showed that the NO donors S-nitrosoglutathione (GSNO) and L-arginine could enhance the antifungal activity of SK, whereas the NO production inhibitor Nω-nitro-L-arginine methyl ester (L-NAME) attenuated antifungal action. Using the fluorescent dye 3-amino,4-aminomethyl-2′, 7-difluorescein, diacetate (DAF-FM DA), we found that the accumulation of NO in C. albicans was increased markedly by SK in a time- and dose-dependent manner. In addition, the results of real-time reverse transcription-PCR (RT-PCR) demonstrated that the transcription level of YHB1 in C. albicans was greatly increased upon incubation of SK. Consistently, the YHB1-null mutant (yhb1Δ/Δ) exhibited a higher susceptibility to SK than wild-type cells. In addition, although the transcription level of CTA4 in C. albicans was not significantly changed when exposed to SK, the CTA4-null mutant (cta4Δ/Δ) was more susceptible to SK. Collectively, SK is the agent found to execute its antifungal activity directly via endogenous NO accumulation, and NO-mediated damage is related to the suppression of YHB1 and the function of CTA4.
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Merhej J, Delaveau T, Guitard J, Palancade B, Hennequin C, Garcia M, Lelandais G, Devaux F. Yap7 is a transcriptional repressor of nitric oxide oxidase in yeasts, which arose from neofunctionalization after whole genome duplication. Mol Microbiol 2015; 96:951-72. [DOI: 10.1111/mmi.12983] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 02/24/2015] [Indexed: 11/27/2022]
Affiliation(s)
- Jawad Merhej
- Sorbonne Universités, UPMC Univ. Paris 06, Institut de Biologie Paris Seine UMR 7238; Laboratoire de biologie computationnelle et quantitative; F-75006 Paris France
- CNRS, UMR 7238; Laboratoire de biologie computationnelle et quantitative; F-75006 Paris France
| | - Thierry Delaveau
- Sorbonne Universités, UPMC Univ. Paris 06, Institut de Biologie Paris Seine UMR 7238; Laboratoire de biologie computationnelle et quantitative; F-75006 Paris France
- CNRS, UMR 7238; Laboratoire de biologie computationnelle et quantitative; F-75006 Paris France
| | - Juliette Guitard
- Sorbonne Universités, UPMC Univ Paris 06, CR7; Centre d'Immunologie et des Maladies Infectieuses (CIMI-Paris); 91 Bd de l'hôpital F-75013 Paris France
- Inserm; U1135; CIMI-Paris; 91 Bd de l'hôpital F-75013 Paris France
- Assistance Publique-Hôpitaux de Paris, Hôpital St Antoine; Service de Parasitologie-Mycologie; F-75012 Paris France
- CNRS; ERL 8255; CIMI-Paris; 91 Bd de l'hôpital F-75013 Paris France
| | - Benoit Palancade
- Institut Jacques Monod, CNRS, UMR 7592, Univ Paris Diderot; Sorbonne Paris Cité; F-75205 Paris France
| | - Christophe Hennequin
- Sorbonne Universités, UPMC Univ Paris 06, CR7; Centre d'Immunologie et des Maladies Infectieuses (CIMI-Paris); 91 Bd de l'hôpital F-75013 Paris France
- Inserm; U1135; CIMI-Paris; 91 Bd de l'hôpital F-75013 Paris France
- Assistance Publique-Hôpitaux de Paris, Hôpital St Antoine; Service de Parasitologie-Mycologie; F-75012 Paris France
- CNRS; ERL 8255; CIMI-Paris; 91 Bd de l'hôpital F-75013 Paris France
| | - Mathilde Garcia
- Sorbonne Universités, UPMC Univ. Paris 06, Institut de Biologie Paris Seine UMR 7238; Laboratoire de biologie computationnelle et quantitative; F-75006 Paris France
- CNRS, UMR 7238; Laboratoire de biologie computationnelle et quantitative; F-75006 Paris France
| | - Gaëlle Lelandais
- Institut Jacques Monod, CNRS, UMR 7592, Univ Paris Diderot; Sorbonne Paris Cité; F-75205 Paris France
| | - Frédéric Devaux
- Sorbonne Universités, UPMC Univ. Paris 06, Institut de Biologie Paris Seine UMR 7238; Laboratoire de biologie computationnelle et quantitative; F-75006 Paris France
- CNRS, UMR 7238; Laboratoire de biologie computationnelle et quantitative; F-75006 Paris France
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Biswas P, Ghosh S. Global transcriptomic profiling of Schizosaccharomyces pombe in response to nitrosative stress. Gene 2015; 558:241-53. [DOI: 10.1016/j.gene.2014.12.067] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2014] [Revised: 12/16/2014] [Accepted: 12/30/2014] [Indexed: 01/25/2023]
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Cuéllar-Cruz M, López-Romero E, Ruiz-Baca E, Zazueta-Sandoval R. Differential response of Candida albicans and Candida glabrata to oxidative and nitrosative stresses. Curr Microbiol 2014; 69:733-9. [PMID: 25002360 DOI: 10.1007/s00284-014-0651-3] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2014] [Accepted: 05/17/2014] [Indexed: 10/25/2022]
Abstract
Invasive candidiasis is associated with high mortality in immunocompromised and hospitalized patients. Candida albicans is the main pathological agent followed by Candida glabrata, Candida krusei, Candida parapsilosis, and Candida tropicalis. These pathogens colonize different host tissues in humans as they are able to neutralize the reactive species generated from nitrogen and oxygen during the respiratory burst. Among the enzymatic mechanisms that Candida species have developed to protect against free radicals are enzymes with antioxidant and immunodominant functions such as flavohemoglobins, catalases, superoxide dismutases, glutathione reductases, thioredoxins, peroxidases, heat-shock proteins, and enolases. These mechanisms are under transcriptional regulation by factors such as Cta4p, Cwt1p, Yap1p, Skn7p, Msn2p, and Msn4p. However, even though it has been proposed that all Candida species have similar enzymatic systems, it has been observed that they respond differentially to various types of stress. These differential responses may explain the colonization of different organs by each species. Here, we review the enzymatic mechanisms developed by C. albicans and C. glabrata species in response to oxidative and nitrosative stresses. Lack of experimental information for other pathogenic species limits a comparative approach among different organisms.
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Affiliation(s)
- Mayra Cuéllar-Cruz
- Departamento de Biología, División de Ciencias Naturales y Exactas, Campus Guanajuato, Universidad de Guanajuato, Noria Alta S/N, C.P. 36050, Guanajuato, Mexico,
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Novel role of a family of major facilitator transporters in biofilm development and virulence of Candida albicans. Biochem J 2014; 460:223-35. [PMID: 24621232 DOI: 10.1042/bj20140010] [Citation(s) in RCA: 43] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
The QDR (quinidine drug resistance) family of genes encodes transporters belonging to the MFS (major facilitator superfamily) of proteins. We show that QDR transporters, which are localized to the plasma membrane, do not play a role in drug transport. Hence, null mutants of QDR1, QDR2 and QDR3 display no alterations in susceptibility to azoles, polyenes, echinocandins, polyamines or quinolines, or to cell wall inhibitors and many other stresses. However, the deletion of QDR genes, individually or collectively, led to defects in biofilm architecture and thickness. Interestingly, QDR-lacking strains also displayed attenuated virulence, but the strongest effect was observed with qdr2∆, qdr3∆ and in qdr1/2/3∆ strains. Notably, the attenuated virulence and biofilm defects could be reversed upon reintegration of QDR genes. Transcripts profiling confirmed differential expression of many biofilm and virulence-related genes in the deletion strains as compared with wild-type Candida albicans cells. Furthermore, lipidomic analysis of QDR-deletion mutants suggests massive remodelling of lipids, which may affect cell signalling, leading to the defect in biofilm development and attenuation of virulence. In summary, the results of the present study show that QDR paralogues encoding MFS antiporters do not display conserved functional linkage as drug transporters and perform functions that significantly affect the virulence of C. albicans.
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Arasimowicz-Jelonek M, Floryszak-Wieczorek J. Nitric oxide: an effective weapon of the plant or the pathogen? MOLECULAR PLANT PATHOLOGY 2014; 15:406-16. [PMID: 24822271 PMCID: PMC6638900 DOI: 10.1111/mpp.12095] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/18/2023]
Abstract
An explosion of research in plant nitric oxide (NO) biology during the last two decades has revealed that NO is a key signal involved in plant development, abiotic stress responses and plant immunity. During the course of evolutionary changes, microorganisms parasitizing plants have developed highly effective offensive strategies, in which NO also seems to be implicated. NO production has been demonstrated in several plant pathogens, including fungi, but the origin of NO seems to be as puzzling as in plants. So far, published studies have been spread over multiple species of pathogenic microorganisms in various developmental stages; however, the data clearly indicate that pathogen-derived NO is an important regulatory molecule involved not only in developmental processes, but also in pathogen virulence and its survival in the host. This review also focuses on the search for potential mechanisms by which pathogens convert NO messages into a physiological response or detoxify both endo- and exogenous NO. Finally, taking into account the data available from model bacteria and yeast, a basic draft for the mode of NO action in phytopathogenic microorganisms is proposed.
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Modeling the transcriptional regulatory network that controls the early hypoxic response in Candida albicans. EUKARYOTIC CELL 2014; 13:675-90. [PMID: 24681685 DOI: 10.1128/ec.00292-13] [Citation(s) in RCA: 51] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
We determined the changes in transcriptional profiles that occur in the first hour following the transfer of Candida albicans to hypoxic growth conditions. The impressive speed of this response is not compatible with current models of fungal adaptation to hypoxia that depend on the depletion of sterol and heme. Functional analysis using Gene Set Enrichment Analysis (GSEA) identified the Sit4 phosphatase, Ccr4 mRNA deacetylase, and Sko1 transcription factor (TF) as potential regulators of the early hypoxic response. Cells mutated in these and other regulators exhibit a delay in their transcriptional responses to hypoxia. Promoter occupancy data for 29 TFs were combined with the transcriptional profiles of 3,111 in vivo target genes in a Network Component Analysis (NCA) to produce a model of the dynamic and highly interconnected TF network that controls this process. With data from the TF network obtained from a variety of sources, we generated an edge and node model that was capable of separating many of the hypoxia-upregulated and -downregulated genes. Upregulated genes are centered on Tye7, Upc2, and Mrr1, which are associated with many of the gene promoters that exhibit the strongest activations. The connectivity of the model illustrates the high redundancy of this response system and the challenges that lie in determining the individual contributions of specific TFs. Finally, treating cells with an inhibitor of the oxidative phosphorylation chain mimics most of the early hypoxic profile, which suggests that this response may be initiated by a drop in ATP production.
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Childers DS, Mundodi V, Banerjee M, Kadosh D. A 5' UTR-mediated translational efficiency mechanism inhibits the Candida albicans morphological transition. Mol Microbiol 2014; 92:570-85. [PMID: 24601998 DOI: 10.1111/mmi.12576] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 03/05/2014] [Indexed: 01/09/2023]
Abstract
While virulence properties of Candida albicans, the most commonly isolated human fungal pathogen, are controlled by transcriptional and post-translational mechanisms, considerably little is known about the role of post-transcriptional, and particularly translational, mechanisms. We demonstrate that UME6, a key filament-specific transcriptional regulator whose expression level is sufficient to determine C. albicans morphology and promote virulence, has one of the longest 5' untranslated regions (UTRs) identified in fungi to date, which is predicted to form a complex and extremely stable secondary structure. The 5' UTR inhibits the ability of UME6, when expressed at constitutive high levels, to drive complete hyphal growth, but does not cause a reduction in UME6 transcript. Deletion of the 5' UTR increases C. albicans filamentation under a variety of conditions but does not affect UME6 transcript level or induction kinetics. We show that the 5' UTR functions to inhibit Ume6 protein expression under several filament-inducing conditions and specifically reduces association of the UME6 transcript with polysomes. Overall, our findings suggest that translational efficiency mechanisms, known to regulate diverse biological processes in bacterial and viral pathogens as well as higher eukaryotes, have evolved to inhibit and fine-tune morphogenesis, a key virulence trait of many human fungal pathogens.
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Affiliation(s)
- Delma S Childers
- Department of Microbiology and Immunology, University of Texas Health Science Center at San Antonio, 7703 Floyd Curl Dr., MC: 7758, San Antonio, TX, 78229-3900, USA
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Castelhano Santos N, Pereira MO, Lourenço A. Pathogenicity phenomena in three model systems: from network mining to emerging system-level properties. Brief Bioinform 2013; 16:169-82. [PMID: 24106130 DOI: 10.1093/bib/bbt071] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023] Open
Abstract
Understanding the interconnections of microbial pathogenicity phenomena, such as biofilm formation, quorum sensing and antimicrobial resistance, is a tremendous open challenge for biomedical research. Progress made by wet-lab researchers and bioinformaticians in understanding the underlying regulatory phenomena has been significant, with converging evidence from multiple high-throughput technologies. Notably, network reconstructions are already of considerable size and quality, tackling both intracellular regulation and signal mediation in microbial infection. Therefore, it stands to reason that in silico investigations would play a more active part in this research. Drug target identification and drug repurposing could take much advantage of the ability to simulate pathogen regulatory systems, host-pathogen interactions and pathogen cross-talking. Here, we review the bioinformatics resources and tools available for the study of the gram-negative bacterium Pseudomonas aeruginosa, the gram-positive bacterium Staphylococcus aureus and the fungal species Candida albicans. The choice of these three microorganisms fits the rationale of the review converging into pathogens of great clinical importance, which thrive in biofilm consortia and manifest growing antimicrobial resistance.
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Kroll K, Pähtz V, Kniemeyer O. Elucidating the fungal stress response by proteomics. J Proteomics 2013; 97:151-63. [PMID: 23756228 DOI: 10.1016/j.jprot.2013.06.001] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2013] [Revised: 05/09/2013] [Accepted: 06/01/2013] [Indexed: 10/26/2022]
Abstract
Fungal species need to cope with stress, both in the natural environment and during interaction of human- or plant pathogenic fungi with their host. Many regulatory circuits governing the fungal stress response have already been discovered. However, there are still large gaps in the knowledge concerning the changes of the proteome during adaptation to environmental stress conditions. With the application of proteomic methods, particularly 2D-gel and gel-free, LC/MS-based methods, first insights into the composition and dynamic changes of the fungal stress proteome could be obtained. Here, we review the recent proteome data generated for filamentous fungi and yeasts. This article is part of a Special Issue entitled: Trends in Microbial Proteomics.
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Affiliation(s)
- Kristin Kroll
- Department of Molecular and Applied Microbiology, Leibniz Institute for Natural Product Research and Infection Biology - Hans-Knöll-Institute (HKI), Beutenbergstrasse 11a, 07745 Jena, Germany; Friedrich Schiller University, Institute of Microbiology, Philosophenweg 12, 07743 Jena, Germany
| | - Vera Pähtz
- Department of Molecular and Applied Microbiology, Leibniz Institute for Natural Product Research and Infection Biology - Hans-Knöll-Institute (HKI), Beutenbergstrasse 11a, 07745 Jena, Germany; Friedrich Schiller University, Institute of Microbiology, Philosophenweg 12, 07743 Jena, Germany; Integrated Research and Treatment Center, Center for Sepsis Control and Care Jena, University Hospital (CSCC), 07747 Jena, Germany
| | - Olaf Kniemeyer
- Department of Molecular and Applied Microbiology, Leibniz Institute for Natural Product Research and Infection Biology - Hans-Knöll-Institute (HKI), Beutenbergstrasse 11a, 07745 Jena, Germany; Friedrich Schiller University, Institute of Microbiology, Philosophenweg 12, 07743 Jena, Germany; Integrated Research and Treatment Center, Center for Sepsis Control and Care Jena, University Hospital (CSCC), 07747 Jena, Germany.
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23
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Thriving within the host: Candida spp. interactions with phagocytic cells. Med Microbiol Immunol 2013; 202:183-95. [DOI: 10.1007/s00430-013-0288-z] [Citation(s) in RCA: 66] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2013] [Accepted: 01/10/2013] [Indexed: 01/04/2023]
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Gardner PR. Hemoglobin: a nitric-oxide dioxygenase. SCIENTIFICA 2012; 2012:683729. [PMID: 24278729 PMCID: PMC3820574 DOI: 10.6064/2012/683729] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/11/2012] [Accepted: 10/04/2012] [Indexed: 05/09/2023]
Abstract
Members of the hemoglobin superfamily efficiently catalyze nitric-oxide dioxygenation, and when paired with native electron donors, function as NO dioxygenases (NODs). Indeed, the NOD function has emerged as a more common and ancient function than the well-known role in O2 transport-storage. Novel hemoglobins possessing a NOD function continue to be discovered in diverse life forms. Unique hemoglobin structures evolved, in part, for catalysis with different electron donors. The mechanism of NOD catalysis by representative single domain hemoglobins and multidomain flavohemoglobin occurs through a multistep mechanism involving O2 migration to the heme pocket, O2 binding-reduction, NO migration, radical-radical coupling, O-atom rearrangement, nitrate release, and heme iron re-reduction. Unraveling the physiological functions of multiple NODs with varying expression in organisms and the complexity of NO as both a poison and signaling molecule remain grand challenges for the NO field. NOD knockout organisms and cells expressing recombinant NODs are helping to advance our understanding of NO actions in microbial infection, plant senescence, cancer, mitochondrial function, iron metabolism, and tissue O2 homeostasis. NOD inhibitors are being pursued for therapeutic applications as antibiotics and antitumor agents. Transgenic NOD-expressing plants, fish, algae, and microbes are being developed for agriculture, aquaculture, and industry.
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Affiliation(s)
- Paul R. Gardner
- Miami Valley Biotech, 1001 E. 2nd Street, Suite 2445, Dayton, OH 45402, USA
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