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Growth and Antifungal Resistance of the Pathogenic Yeast, Candida Albicans, in the Microgravity Environment of the International Space Station: An Aggregate of Multiple Flight Experiences. Life (Basel) 2021; 11:life11040283. [PMID: 33801697 PMCID: PMC8067245 DOI: 10.3390/life11040283] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2021] [Revised: 03/25/2021] [Accepted: 03/25/2021] [Indexed: 12/13/2022] Open
Abstract
This report was designed to compare spaceflight-induced cellular and physiological adaptations of Candida albicans cultured in microgravity on the International Space Station across several payloads. C. albicans is a common opportunistic fungal pathogen responsible for a variety of superficial infections as well as systemic and more severe infections in humans. Cumulatively, the propensity of this organism to be widespread through the population, the ability to produce disease in immunocompromised individuals, and the tendency to respond to environmental stress with characteristics associated with increased virulence, require a better understanding of the yeast response to microgravity for spaceflight crew safety. As such, the responses of this yeast cultivated during several missions using two in-flight culture bioreactors were analyzed and compared herein. In general, C. albicans had a slightly shorter generation time and higher growth propensity in microgravity as compared to terrestrial controls. Rates of cell filamentation differed between bioreactors, but were low and not significantly different between flight and terrestrial controls. Viable cells were retrieved and cultured, resulting in a colony morphology that was similar between cells cultivated in flight and in terrestrial control conditions, and in contrast to that previously observed in a ground-based microgravity analog system. Of importance, yeast demonstrated an increased resistance when challenged during spaceflight with the antifungal agent, amphotericin B. Similar levels of resistance were not observed when challenged with the functionally disparate antifungal drug caspofungin. In aggregate, yeast cells cultivated in microgravity demonstrated a subset of characteristics associated with virulence. In addition, and beyond the value of the specific responses of C. albicans to microgravity, this report includes an analysis of biological reproducibility across flight opportunities, compares two spaceflight hardware systems, and includes a summary of general flight and payload timelines.
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Gbotsyo YA, Rowarth NM, Weir LK, MacRae TH. Short-term cold stress and heat shock proteins in the crustacean Artemia franciscana. Cell Stress Chaperones 2020; 25:1083-1097. [PMID: 32794096 PMCID: PMC7591681 DOI: 10.1007/s12192-020-01147-4] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2020] [Revised: 07/02/2020] [Accepted: 07/28/2020] [Indexed: 01/09/2023] Open
Abstract
In their role as molecular chaperones, heat shock proteins (Hsps) mediate protein folding thereby mitigating cellular damage caused by physiological and environmental stress. Nauplii of the crustacean Artemia franciscana respond to heat shock by producing Hsps; however, the effects of cold shock on Hsp levels in A. franciscana have not been investigated previously. The effect of cold shock at 1 °C followed by recovery at 27 °C on the amounts of ArHsp90, Hsp70, ArHsp40, and ArHsp40-2 mRNA and their respective proteins in A. franciscana nauplii was examined by quantitative PCR (qPCR) and immunoprobing of western blots. The same Hsp mRNAs and proteins were also quantified during incubation of nauplii at their optimal growth temperature of 27 °C. qPCR analyses indicated that the abundance of ArHsp90, Hsp70, and ArHsp40 mRNA remained relatively constant during both cold shock and recovery and was not significantly different compared with levels at optimal temperature. Western blotting revealed that ArHsp90, ArHsp40, and ArHsp40-2 were generally below baseline, but at detectable levels during the 6 h of cold shock, and persisted in early recovery stages before declining. Hsp70 was the only protein that remained constant in quantity throughout cold shock and recovery. By contrast, all Hsps declined rapidly during 6 h when nauplii were incubated continuously at 27 °C optimal temperature. Generally, the amounts of ArHsp90, ArHsp40, and ArHsp40-2 were higher during cold shock/recovery than those during continuous incubation at 27 °C. Our data support the conclusion that low temperature preserves Hsp levels, making them available to assist in protein repair and recovery after cold shock.
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Affiliation(s)
- Yayra A Gbotsyo
- Department of Biology, Dalhousie University, Halifax, N. S., B3H 4R2, Canada
| | - Nathan M Rowarth
- Department of Biology, Dalhousie University, Halifax, N. S., B3H 4R2, Canada
| | - Laura K Weir
- Biology Department, Saint Mary's University Halifax, Halifax, N. S., B3H 3C3, Canada.
| | - Thomas H MacRae
- Department of Biology, Dalhousie University, Halifax, N. S., B3H 4R2, Canada
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What do we know about the biology of the emerging fungal pathogen of humans Candida auris? Microbiol Res 2020; 242:126621. [PMID: 33096325 DOI: 10.1016/j.micres.2020.126621] [Citation(s) in RCA: 28] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2020] [Revised: 09/25/2020] [Accepted: 10/04/2020] [Indexed: 02/07/2023]
Abstract
Candida auris is a worrisome fungal pathogen of humans which emerged merely about a decade ago. Ever since then the scientific community worked hard to understand clinically relevant traits, such as virulence factors, antifungal resistance mechanisms, and its ability to adhere to human skin and medical devices. Whole-genome sequencing of clinical isolates and epidemiological studies outlining the path of nosocomial outbreaks have been the focus of research into this pathogenic and multidrug-resistant yeast since its first description in 2009. More recently, work was started by several laboratories to explore the biology of C. auris. Here, we review the insights of studies characterizing the mechanisms underpinning antifungal drug resistance, biofilm formation, morphogenetic switching, cell aggregation, virulence, and pathogenicity of C. auris. We conclude that, although some progress has been made, there is still a long journey ahead of us, before we fully understand this novel pathogen. Critically important is the development of molecular tools for C. auris to make this fungus genetically tractable and traceable. This will allow an in-depth molecular dissection of the life cycle of C. auris, of its characteristics while interacting with the human host, and the mechanisms it employs to avoid being killed by antifungals and the immune system.
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Paracoccidioides HSP90 Can Be Found in the Cell Surface and Is a Target for Antibodies with Therapeutic Potential. J Fungi (Basel) 2020; 6:jof6040193. [PMID: 32998395 PMCID: PMC7712200 DOI: 10.3390/jof6040193] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2020] [Revised: 09/05/2020] [Accepted: 09/10/2020] [Indexed: 11/17/2022] Open
Abstract
Paracoccidioidomycosis (PCM) is one of the most frequent systemic mycoses in Latin America. It affects mainly male rural workers in impoverished regions, and the therapy can last up to two years or use drugs that are very toxic. Given the need for novel safe and effective approaches to treat PCM, we have been developing monoclonal antibodies (mAbs) that could be used not only to block specific fungal targets, but also modulate the host’s antifungal immunity. In this work we show the generation of and promising results with an mAb against Heat Shock Protein (HSP)90, a molecular chaperone that is an important virulence factor in fungi. Using recombinant Paracoccidioides lutzii (Pb01) and P. brasiliensis (Pb18) HSP90 proteins produced in E. coli, we immunized mice and generated polyclonal antibodies and an IgG1 hybridoma mAb. The proteins were very immunogenic and both the polyclonal serum and mAb were used in immunofluorescence experiments, which showed binding of antibodies to the yeast cell surface. The mAb successfully opsonized P. lutzii and P. brasiliensis cells in co-incubations with J774.16 macrophage-like cells. Our results suggest that this mAb could serve as the basis for new immunotherapy regimens for PCM.
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Mba IE, Nweze EI. Mechanism of Candida pathogenesis: revisiting the vital drivers. Eur J Clin Microbiol Infect Dis 2020; 39:1797-1819. [PMID: 32372128 DOI: 10.1007/s10096-020-03912-w] [Citation(s) in RCA: 46] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2020] [Accepted: 04/17/2020] [Indexed: 12/14/2022]
Abstract
Candida is the most implicated fungal pathogen in the clinical setting. Several factors play important roles in the pathogenesis of Candida spp. Multiple transcriptional circuits, morphological and phenotypic switching, biofilm formation, tissue damaging extracellular hydrolytic enzymes, metabolic flexibility, genome plasticity, adaptation to environmental pH fluctuation, robust nutrient acquisition system, adherence and invasions (mediated by adhesins and invasins), heat shock proteins (HSPs), cytolytic proteins, escape from phagocytosis, evasion from host immune system, synergistic coaggregation with resident microbiota, resistance to antifungal agents, and the ability to efficiently respond to multiple stresses are some of the major pathogenic determinants of Candida species. The existence of multiple connections, in addition to the interactions and associations among all of these factors, are distinctive features that play important roles in the establishment of Candida infections. This review describes all the underlying factors and mechanisms involved in Candida pathogenesis by evaluating pathogenic determinants of Candida species. It reinforces the already available pool of data on the pathogenesis of Candida species by providing a clear and simplified understanding of the most important factors implicated in the pathogenesis of Candida species. The Candida pathogenesis network, an illustration linking all the major determinants of Candida pathogenesis, is also presented. Taken together, they will further improve our current understanding of how these factors modulate virulence and consequent infection(s). Development of new antifungal drugs and better therapeutic approaches to candidiasis can be achieved in the near future with continuing progress in the understanding of the mechanisms of Candida pathogenesis.
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Pseudohyphal Growth of the Emerging Pathogen Candida auris Is Triggered by Genotoxic Stress through the S Phase Checkpoint. mSphere 2020; 5:5/2/e00151-20. [PMID: 32161147 PMCID: PMC7067593 DOI: 10.1128/msphere.00151-20] [Citation(s) in RCA: 28] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
Candida auris is a newly emerged fungal pathogen of humans. This species was first reported in 2009 when it was identified in an ear infection of a patient in Japan. However, despite intense interest in this organism as an often multidrug-resistant fungus, there is little knowledge about its cellular biology. During infection of human patients, fungi are able to change cell shape from ellipsoidal yeast cells to elongated filaments to adapt to various conditions within the host organism. There are different types of filaments, which are triggered by reactions to different cues. Candida auris fails to form filaments when exposed to triggers that stimulate yeast filament morphogenesis in other fungi. Here, we show that it does form filaments when its DNA is damaged. These conditions might arise when Candida auris cells interact with host immune cells or during growth in certain host tissues (kidney or bladder) or during treatment with antifungal drugs. The morphogenetic switching between yeast cells and filaments (true hyphae and pseudohyphae) is a key cellular feature required for full virulence in many polymorphic fungal pathogens, such as Candida albicans. In the recently emerged yeast pathogen Candida auris, occasional elongation of cells has been reported. However, environmental conditions and genetic triggers for filament formation have remained elusive. Here, we report that induction of DNA damage and perturbation of replication forks by treatment with genotoxins, such as hydroxyurea, methyl methanesulfonate, and the clinically relevant fungistatic 5-fluorocytosine, cause filamentation in C. auris. The filaments formed were characteristic of pseudohyphae and not parallel-sided true hyphae. Pseudohyphal growth is apparently signaled through the S phase checkpoint and, interestingly, is Tup1 independent in C. auris. Intriguingly, the morphogenetic switching capability is strain specific in C. auris, highlighting the heterogenous nature of the species as a whole. IMPORTANCECandida auris is a newly emerged fungal pathogen of humans. This species was first reported in 2009 when it was identified in an ear infection of a patient in Japan. However, despite intense interest in this organism as an often multidrug-resistant fungus, there is little knowledge about its cellular biology. During infection of human patients, fungi are able to change cell shape from ellipsoidal yeast cells to elongated filaments to adapt to various conditions within the host organism. There are different types of filaments, which are triggered by reactions to different cues. Candida auris fails to form filaments when exposed to triggers that stimulate yeast filament morphogenesis in other fungi. Here, we show that it does form filaments when its DNA is damaged. These conditions might arise when Candida auris cells interact with host immune cells or during growth in certain host tissues (kidney or bladder) or during treatment with antifungal drugs.
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Kim SW, Park YK, Joo YJ, Chun YJ, Hwang JY, Baek JH, Kim J. Subunits of the vacuolar H+-ATPase complex, Vma4 and Vma10, are essential for virulence and represent potential drug targets in Candida albicans. Fungal Biol 2019; 123:709-722. [DOI: 10.1016/j.funbio.2019.06.002] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2019] [Revised: 05/20/2019] [Accepted: 06/03/2019] [Indexed: 01/26/2023]
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Veri AO, Robbins N, Cowen LE. Regulation of the heat shock transcription factor Hsf1 in fungi: implications for temperature-dependent virulence traits. FEMS Yeast Res 2019; 18:4975774. [PMID: 29788061 DOI: 10.1093/femsyr/foy041] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2017] [Accepted: 04/16/2018] [Indexed: 12/27/2022] Open
Abstract
The impact of fungal pathogens on human health is devastating. For fungi and other pathogens, a key determinant of virulence is the capacity to thrive at host temperatures, with elevated temperature in the form of fever as a ubiquitous host response to defend against infection. A prominent feature of cells experiencing heat stress is the increased expression of heat shock proteins (Hsps) that play pivotal roles in the refolding of misfolded proteins in order to restore cellular homeostasis. Transcriptional activation of this heat shock response is orchestrated by the essential heat shock transcription factor, Hsf1. Although the influence of Hsf1 on cellular stress responses has been studied for decades, many aspects of its regulation and function remain largely enigmatic. In this review, we highlight our current understanding of how Hsf1 is regulated and activated in the model yeast Saccharomyces cerevisiae, and highlight exciting recent discoveries related to its diverse functions under both basal and stress conditions. Given that thermal adaption is a fundamental requirement for growth and virulence in fungal pathogens, we also compare and contrast Hsf1 activation and function in other fungal species with an emphasis on its role as a critical regulator of virulence traits.
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Affiliation(s)
- Amanda O Veri
- Department of Molecular Genetics, University of Toronto, Toronto, ON M5G 1M1, Canada
| | - Nicole Robbins
- Department of Molecular Genetics, University of Toronto, Toronto, ON M5G 1M1, Canada
| | - Leah E Cowen
- Department of Molecular Genetics, University of Toronto, Toronto, ON M5G 1M1, Canada
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Sharma J, Rosiana S, Razzaq I, Shapiro RS. Linking Cellular Morphogenesis with Antifungal Treatment and Susceptibility in Candida Pathogens. J Fungi (Basel) 2019; 5:E17. [PMID: 30795580 PMCID: PMC6463059 DOI: 10.3390/jof5010017] [Citation(s) in RCA: 35] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2019] [Revised: 02/11/2019] [Accepted: 02/13/2019] [Indexed: 02/07/2023] Open
Abstract
Fungal infections are a growing public health concern, and an increasingly important cause of human mortality, with Candida species being amongst the most frequently encountered of these opportunistic fungal pathogens. Several Candida species are polymorphic, and able to transition between distinct morphological states, including yeast, hyphal, and pseudohyphal forms. While not all Candida pathogens are polymorphic, the ability to undergo morphogenesis is linked with the virulence of many of these pathogens. There are also many connections between Candida morphogenesis and antifungal drug treatment and susceptibility. Here, we review how Candida morphogenesis-a key virulence trait-is linked with antifungal drugs and antifungal drug resistance. We highlight how antifungal therapeutics are able to modulate morphogenesis in both sensitive and drug-resistant Candida strains, the shared signaling pathways that mediate both morphogenesis and the cellular response to antifungal drugs and drug resistance, and the connection between Candida morphology, drug resistance, and biofilm growth. We further review the development of anti-virulence drugs, and targeting Candida morphogenesis as a novel therapeutic strategy to target fungal pathogens. Together, this review highlights important connections between fungal morphogenesis, virulence, and susceptibility to antifungals.
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Affiliation(s)
- Jehoshua Sharma
- Department of Molecular and Cellular Biology, University of Guelph, Guelph, ON N1G 2W1, Canada.
| | - Sierra Rosiana
- Department of Molecular and Cellular Biology, University of Guelph, Guelph, ON N1G 2W1, Canada.
| | - Iqra Razzaq
- Department of Molecular and Cellular Biology, University of Guelph, Guelph, ON N1G 2W1, Canada.
| | - Rebecca S Shapiro
- Department of Molecular and Cellular Biology, University of Guelph, Guelph, ON N1G 2W1, Canada.
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Liu YH, Liu XM, Wang PC, Yu XX, Miao JK, Liu S, Wang YK, Du ZQ, Yang CX. Heat shock protein 90α couples with the MAPK-signaling pathway to determine meiotic maturation of porcine oocytes. J Anim Sci 2018; 96:3358-3369. [PMID: 29800308 DOI: 10.1093/jas/sky213] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2018] [Accepted: 05/24/2018] [Indexed: 12/20/2022] Open
Abstract
Heat shock protein 90 (Hsp90) functions as a molecular chaperone in its interaction with clients to influence multiple cellular and physiological processes. However, our current understanding on Hsp90's relationship with mammalian oocyte maturation is still very limited. Here, we aimed to investigate Hsp90's effect on pig oocyte meiotic maturation. Endogenous Hsp90α was constantly expressed at both mRNA and protein levels in porcine maturing oocytes. Addition of 2 µM 17-allylamino-17-demethoxygeldanamycin (17-AAG), the Hsp90 inhibitor, to in vitro mature cumulus-oocyte complexes (COC) significantly decreased Hsp90α protein level (P < 0.05), delayed germinal vesicle breakdown (GVBD) (P < 0.05), and impeded the first polar body (PB1) extrusion (P < 0.01) of porcine oocytes. 2 µM 17-AAG treatment during in vitro maturation also decreased the subsequent development competence as indicated by the lower cleavage (P < 0.001) and higher fragmentation (P < 0.001) rates of parthenotes, whereas no effects on the percentage and average cell number of blastocysts were found. Immunodepletion of Hsp90α by antibody microinjection into porcine oocytes at germinal vesicle and metaphase II stages induced similar defects of meiotic maturation and parthenote development, to that resulted from 2 µM inhibitor 17-AAG. For oocytes treated by 2 µM 17-AAG, the cytoplasm and membrane actin levels were weakened (P < 0.01), and the spindle assembly was disturbed (P < 0.05), due to decreased p-ERK1/2 level (P < 0.05). However, the mitochondrial function and early apoptosis were not affected, as demonstrated by rhodamine 123 staining and Annexin V assays. Our findings indicate that Hsp90α can couple with mitogen-activated protein kinase to regulate cytoskeletal structure and orchestrate meiotic maturation of porcine oocytes.
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Affiliation(s)
- Yun-Hua Liu
- College of Animal Science and Technology, Northeast Agricultural University, Harbin, Heilongjiang, China
| | - Xiao-Man Liu
- College of Animal Science and Technology, Northeast Agricultural University, Harbin, Heilongjiang, China
| | - Pei-Chao Wang
- College of Animal Science and Technology, Northeast Agricultural University, Harbin, Heilongjiang, China
| | - Xiao-Xia Yu
- College of Animal Science and Technology, Northeast Agricultural University, Harbin, Heilongjiang, China
| | - Jia-Kun Miao
- College of Animal Science and Technology, Northeast Agricultural University, Harbin, Heilongjiang, China
| | - Shuai Liu
- College of Animal Science and Technology, Northeast Agricultural University, Harbin, Heilongjiang, China
| | - Yan-Kui Wang
- College of Animal Science and Technology, Northeast Agricultural University, Harbin, Heilongjiang, China
| | - Zhi-Qiang Du
- College of Animal Science and Technology, Northeast Agricultural University, Harbin, Heilongjiang, China
| | - Cai-Xia Yang
- College of Animal Science and Technology, Northeast Agricultural University, Harbin, Heilongjiang, China
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Su C, Yu J, Lu Y. Hyphal development in Candida albicans from different cell states. Curr Genet 2018; 64:1239-1243. [PMID: 29796903 DOI: 10.1007/s00294-018-0845-5] [Citation(s) in RCA: 25] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2018] [Revised: 05/15/2018] [Accepted: 05/15/2018] [Indexed: 01/01/2023]
Abstract
Candida albicans is an important opportunistic fungal pathogen of immunocompromised individuals. The ability to switch between yeast, pseudohyphal, and hyphal growth forms (polymorphism) is one of the most investigated virulence attributes of C. albicans. The usual method for inducing hypha formation in the lab is by diluting cells from a saturated culture into fresh medium at 37 °C. The molecular mechanism at action under these conditions has been previously investigated. C. albicans can also form hyphae in growing cells without dilution. The ability of C. albicans to form hyphae in different cell states facilitates the fungus to adapt varied host environments during infection. A recent study by Su et al. uncovered the molecular mechanism for how C. albicans develops hyphae under the condition without inoculation. N-Acetylglucosamine (GlcNAc) stimulates filamentation in log phase cells through transcriptional down-regulation of NRG1, the major repressor of hyphal development. Instead of cAMP-PKA pathway, GlcNAc sensor Ngs1 is responsible for this process. Ngs1 binds to GlcNAc to activate its N-acetyltransferase activity, leading to the induction of BRG1 expression. The increased level of BRG1 could repress NRG1 transcripts, resulting in hyphal growth. Hyphal development in log phase cells induced by serum or neutral pH also requires activation of BRG1 to down-regulate NRG1 transcription. Therefore, hyphal induction under the condition without inoculation is trigged by Brg1-mediated removal of Nrg1 inhibition. This review describes our current understanding of the molecular mechanism underlying hyphal development, the best studied virulence factor in C. albicans. These will expand the number of potential drug targets with novel modes of action for anti-virulence therapeutics.
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Affiliation(s)
- Chang Su
- Hubei Key Laboratory of Cell Homeostasis, College of Life Sciences, Wuhan University, Wuhan, 430072, China
| | - Jing Yu
- Hubei Key Laboratory of Cell Homeostasis, College of Life Sciences, Wuhan University, Wuhan, 430072, China
| | - Yang Lu
- Hubei Key Laboratory of Cell Homeostasis, College of Life Sciences, Wuhan University, Wuhan, 430072, China.
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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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Su C, Yu J, Sun Q, Liu Q, Lu Y. Hyphal induction under the condition without inoculation in Candida albicans is triggered by Brg1-mediated removal of NRG1 inhibition. Mol Microbiol 2018; 108:410-423. [PMID: 29485686 DOI: 10.1111/mmi.13944] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 02/24/2018] [Indexed: 12/28/2022]
Abstract
Candida albicans can switch between yeast and hyphae growth forms, which is critical for its pathogenesis. Diluting from saturated cells into fresh medium at 37°C is routinely used to induce hyphae, which depends on the cAMP-PKA pathway-activated transcriptional down-regulation of NRG1 and degradation of Nrg1 protein triggered by inoculation. It is reported that N-acetylglucosamine (GlcNAc), serum or neutral pH could stimulate filamentation in log phase cells, whereas how C. albicans develops hyphae without inoculation remains unknown. Here, we show that NRG1 down-regulation is necessary for hyphal growth under this condition. Instead of cAMP-PKA pathway, GlcNAc sensor Ngs1 is responsible for the down-regulation of NRG1 upon GlcNAc induction in log phase cells through its N-acetyltransferase activity. From a genetic screen, Brg1 is found to be essential for hyphal development without inoculation. Ngs1 binds to BRG1 promoter to induce its expression in GlcNAc. Importantly, constitutively expressed BRG1 induces NRG1 down-regulation even in the absence of GlcNAc or Ngs1. Serum or neutral pH-induced filamentation in log phase cells is also through Brg1-mediated NRG1 down-regulation. Our study provides a molecular mechanism for how C. albicans forms hyphae in different cell states. This flexibility may facilitate C. albicans to adapt varied host environment during infection.
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Affiliation(s)
- Chang Su
- Hubei Key Laboratory of Cell Homeostasis, College of Life Sciences, Wuhan University, Wuhan, China
| | - Jing Yu
- Hubei Key Laboratory of Cell Homeostasis, College of Life Sciences, Wuhan University, Wuhan, China
| | - Qiangqiang Sun
- Hubei Key Laboratory of Cell Homeostasis, College of Life Sciences, Wuhan University, Wuhan, China
| | - Qian Liu
- Hubei Key Laboratory of Cell Homeostasis, College of Life Sciences, Wuhan University, Wuhan, China
| | - Yang Lu
- Hubei Key Laboratory of Cell Homeostasis, College of Life Sciences, Wuhan University, Wuhan, China
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Modulation of the Fungal-Host Interaction by the Intra-Species Diversity of C. albicans. Pathogens 2018; 7:pathogens7010011. [PMID: 29342100 PMCID: PMC5874737 DOI: 10.3390/pathogens7010011] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2017] [Revised: 01/11/2018] [Accepted: 01/12/2018] [Indexed: 01/09/2023] Open
Abstract
The incidence of human infections caused by the opportunistic fungal pathogen Candida albicans is on the rise due to increasing numbers of immunosuppressed patients. The importance of the immune system in preventing overgrowth of the colonizing fungus and thereby limiting infection is well recognized and host protective mechanisms widely investigated. Only recently, it was recognized that the natural diversity in the fungal species could also influence the outcome of the interaction between the fungus and the host. C. albicans strain-specific differences are complex and their regulation at the genomic, genetic, and epigenetic level and by environmental factors is only partially understood. In this review, we provide an overview of the natural diversity of C. albicans and discuss how it impacts host-fungal interactions and thereby affects the balance between commensalism versus disease.
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15
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Kochi Y, Matsumoto Y, Sekimizu K, Kaito C. Two-spotted cricket as an animal infection model of human pathogenic fungi. Drug Discov Ther 2017; 11:259-266. [PMID: 29081438 DOI: 10.5582/ddt.2017.01052] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
Invertebrate infection models that can be evaluated at human body temperature are limited. In this study, we utilized the two-spotted cricket, a heat-tolerant insect, as an animal infection model of human pathogenic fungi. Injection of human pathogenic fungi, including Candida albicans, Candida glabrata, and Cryptococcus neoformans killed crickets within 48 h at both 27˚C and 37˚C. The median lethal dose values (LD50 values) of C. albicans and C. glabrata against crickets were decreased at 37˚C compared to that at 27˚C, whereas the LD50 value of C. neoformans was not different between 27˚C and 37˚C. Heat-killed cells of the three different fungi also killed crickets, but the LD50 value of the heat-killed cells was higher than 5-fold that of live fungal cells in the respective species. C. neoformans gene-knockout strains of cna1, gpa1, and pka1, which are required for virulence in mammals, had greater LD50 values than the parent strain in crickets. These findings suggest that the two-spotted cricket is a valuable infection model of human pathogenic fungi that can be used to evaluate fungal virulence at variable temperatures, including 37˚C, and that the killing abilities of C. albicans and C. glabrata against animals are increased at 37˚C.
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Affiliation(s)
- Yuto Kochi
- Laboratory of Microbiology, Graduate School of Pharmaceutical Sciences, The University of Tokyo
| | | | | | - Chikara Kaito
- Laboratory of Microbiology, Graduate School of Pharmaceutical Sciences, The University of Tokyo
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16
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Li X, Robbins N, O'Meara TR, Cowen LE. Extensive functional redundancy in the regulation of Candida albicans drug resistance and morphogenesis by lysine deacetylases Hos2, Hda1, Rpd3 and Rpd31. Mol Microbiol 2016; 103:635-656. [PMID: 27868254 DOI: 10.1111/mmi.13578] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 11/10/2016] [Indexed: 12/22/2022]
Abstract
Current treatment efforts for fungal infections are hampered by the limited availability of antifungal drugs and by the emergence of drug resistance. A powerful strategy to enhance the efficacy of antifungal drugs is to inhibit the molecular chaperone Hsp90. Hsp90 governs drug resistance, morphogenesis and virulence in a leading fungal pathogen of humans, Candida albicans. Our previous work with Saccharomyces cerevisiae established acetylation as a novel mechanism of posttranslational control of Hsp90 function in fungi. We implicated lysine deacetylases (KDACs) as key regulators of resistance to the most widely deployed class of antifungals, the azoles, in both S. cerevisiae and C. albicans. Here, we demonstrate high levels of functional redundancy among the KDACs that are important for regulating Hsp90 function. We identify Hos2, Hda1, Rpd3 and Rpd31 as the KDACs mediating azole resistance and morphogenesis in C. albicans. Furthermore, we identify lysine 30 and 271 as critical acetylation sites on C. albicans Hsp90, and substitutions at these residues compromise Hsp90 function. Finally, we show that pharmacological inhibition of KDACs phenocopies pharmacological inhibition of Hsp90 and abrogates Hsp90-dependent azole resistance in numerous Candida species. This work illuminates new facets to the impact of KDACs on fungal drug resistance and morphogenesis, provides important insights into the divergence of the C. albicans Hsp90 regulatory network and reveals new targets for development of antifungal drugs.
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Affiliation(s)
- Xinliu Li
- Department of Molecular Genetics, University of Toronto, Toronto, Ontario, M5S 1A8, Canada
| | - Nicole Robbins
- Department of Molecular Genetics, University of Toronto, Toronto, Ontario, M5S 1A8, Canada
| | - Teresa R O'Meara
- Department of Molecular Genetics, University of Toronto, Toronto, Ontario, M5S 1A8, Canada
| | - Leah E Cowen
- Department of Molecular Genetics, University of Toronto, Toronto, Ontario, M5S 1A8, Canada
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17
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Abstract
ABSTRACT
Invasive fungal infections are becoming an increasingly important cause of human mortality and morbidity, particularly for immunocompromised populations. The fungal pathogens
Candida albicans
,
Cryptococcus neoformans
, and
Aspergillus fumigatus
collectively contribute to over 1 million human deaths annually. Hence, the importance of safe and effective antifungal therapeutics for the practice of modern medicine has never been greater. Given that fungi are eukaryotes like their human host, the number of unique molecular targets that can be exploited for drug development remains limited. Only three classes of molecules are currently approved for the treatment of invasive mycoses. The efficacy of these agents is compromised by host toxicity, fungistatic activity, or the emergence of drug resistance in pathogen populations. Here we describe our current arsenal of antifungals and highlight current strategies that are being employed to improve the therapeutic safety and efficacy of these drugs. We discuss state-of-the-art approaches to discover novel chemical matter with antifungal activity and highlight some of the most promising new targets for antifungal drug development. We feature the benefits of combination therapy as a strategy to expand our current repertoire of antifungals and discuss the antifungal combinations that have shown the greatest potential for clinical development. Despite the paucity of new classes of antifungals that have come to market in recent years, it is clear that by leveraging innovative approaches to drug discovery and cultivating collaborations between academia and industry, there is great potential to bolster the antifungal armamentarium.
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18
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Polvi EJ, Averette AF, Lee SC, Kim T, Bahn YS, Veri AO, Robbins N, Heitman J, Cowen LE. Metal Chelation as a Powerful Strategy to Probe Cellular Circuitry Governing Fungal Drug Resistance and Morphogenesis. PLoS Genet 2016; 12:e1006350. [PMID: 27695031 PMCID: PMC5047589 DOI: 10.1371/journal.pgen.1006350] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2016] [Accepted: 09/08/2016] [Indexed: 01/01/2023] Open
Abstract
Fungal pathogens have evolved diverse strategies to sense host-relevant cues and coordinate cellular responses, which enable virulence and drug resistance. Defining circuitry controlling these traits opens new opportunities for chemical diversity in therapeutics, as the cognate inhibitors are rarely explored by conventional screening approaches. This has great potential to address the pressing need for new therapeutic strategies for invasive fungal infections, which have a staggering impact on human health. To explore this approach, we focused on a leading human fungal pathogen, Candida albicans, and screened 1,280 pharmacologically active compounds to identify those that potentiate the activity of echinocandins, which are front-line therapeutics that target fungal cell wall synthesis. We identified 19 compounds that enhance activity of the echinocandin caspofungin against an echinocandin-resistant clinical isolate, with the broad-spectrum chelator DTPA demonstrating the greatest synergistic activity. We found that DTPA increases susceptibility to echinocandins via chelation of magnesium. Whole genome sequencing of mutants resistant to the combination of DTPA and caspofungin identified mutations in the histidine kinase gene NIK1 that confer resistance to the combination. Functional analyses demonstrated that DTPA activates the mitogen-activated protein kinase Hog1, and that NIK1 mutations block Hog1 activation in response to both caspofungin and DTPA. The combination has therapeutic relevance as DTPA enhanced the efficacy of caspofungin in a mouse model of echinocandin-resistant candidiasis. We found that DTPA not only reduces drug resistance but also modulates morphogenesis, a key virulence trait that is normally regulated by environmental cues. DTPA induced filamentation via depletion of zinc, in a manner that is contingent upon Ras1-PKA signaling, as well as the transcription factors Brg1 and Rob1. Thus, we establish a new mechanism by which metal chelation modulates morphogenetic circuitry and echinocandin resistance, and illuminate a novel facet to metal homeostasis at the host-pathogen interface, with broad therapeutic potential. Invasive fungal infections pose a serious threat to human health worldwide, with Candida albicans being a leading fungal pathogen. Mortality is in part due to the limited arsenal of effective antifungals, with drug resistance on the rise. The echinocandins, which target the fungal cell wall, are the newest class of antifungal, and echinocandin resistance has already emerged. Here, we screened a library of 1,280 pharmacologically active compounds to identify those that potentiate echinocandin activity against an echinocandin-resistant isolate. The lead compound was a chelator, DTPA, which affects resistance by depleting magnesium. Genome sequencing of mutants resistant to the combination of DTPA and echinocandin revealed mutations in the gene encoding Nik1, which signals upstream of the Hog1 stress response pathway. We established that DTPA acts through Nik1 to modulate Hog1 signaling and enhance echinocandin activity, and that this combination has therapeutic benefits in a murine model of candidiasis. We also discovered that DTPA modulates C. albicans morphogenesis, a key virulence trait. DTPA induced filamentation by chelating zinc, in a manner that is contingent upon core filamentation pathways and specialized circuitry. Thus, we establish novel roles for metal homeostasis in C. albicans pathogenesis, thereby illuminating new therapeutic strategies for life-threatening infectious disease.
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Affiliation(s)
- Elizabeth J. Polvi
- Department of Molecular Genetics, University of Toronto, Toronto, Ontario, Canada
| | - Anna F. Averette
- Department of Molecular Genetics and Microbiology, Medicine, and Pharmacology and Cancer Biology, Duke University Medical Center, Durham, North Carolina, United States of America
| | - Soo Chan Lee
- Department of Molecular Genetics and Microbiology, Medicine, and Pharmacology and Cancer Biology, Duke University Medical Center, Durham, North Carolina, United States of America
- Department of Biology, University of Texas at San Antonio, San Antonio, Texas, United States of America
| | - Taeyup Kim
- Department of Molecular Genetics and Microbiology, Medicine, and Pharmacology and Cancer Biology, Duke University Medical Center, Durham, North Carolina, United States of America
| | - Yong-Sun Bahn
- Department of Biochemistry, College of Life Science and Biotechnology, Yonsei University, Seoul, Republic of Korea
| | - Amanda O. Veri
- Department of Molecular Genetics, University of Toronto, Toronto, Ontario, Canada
| | - Nicole Robbins
- Department of Molecular Genetics, University of Toronto, Toronto, Ontario, Canada
| | - Joseph Heitman
- Department of Molecular Genetics and Microbiology, Medicine, and Pharmacology and Cancer Biology, Duke University Medical Center, Durham, North Carolina, United States of America
| | - Leah E. Cowen
- Department of Molecular Genetics, University of Toronto, Toronto, Ontario, Canada
- * E-mail:
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19
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Saraswat D, Kumar R, Pande T, Edgerton M, Cullen PJ. Signalling mucin Msb2 Regulates adaptation to thermal stress in Candida albicans. Mol Microbiol 2016; 100:425-41. [PMID: 26749104 PMCID: PMC4955288 DOI: 10.1111/mmi.13326] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 01/06/2016] [Indexed: 12/13/2022]
Abstract
Temperature is a potent inducer of fungal dimorphism. Multiple signalling pathways control the response to growth at high temperature, but the sensors that regulate these pathways are poorly defined. We show here that the signalling mucin Msb2 is a global regulator of temperature stress in the fungal pathogen Candida albicans. Msb2 was required for survival and hyphae formation at 42°C. The cytoplasmic signalling domain of Msb2 regulated temperature-dependent activation of the CEK mitogen activated proteins kinase (MAPK) pathway. The extracellular glycosylated domain of Msb2 (100-900 amino acid residues) had a new and unexpected role in regulating the protein kinase C (PKC) pathway. Msb2 also regulated temperature-dependent induction of genes encoding regulators and targets of the unfolded protein response (UPR), which is a protein quality control (QC) pathway in the endoplasmic reticulum that controls protein folding/degradation in response to high temperature and other stresses. The heat shock protein and cell wall component Ssa1 was also required for hyphae formation and survival at 42°C and regulated the CEK and PKC pathways.
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Affiliation(s)
- Darpan Saraswat
- Department of Oral Biology, University at Buffalo, Buffalo, NY, 14260-1300, USA
| | - Rohitashw Kumar
- Department of Oral Biology, University at Buffalo, Buffalo, NY, 14260-1300, USA
| | - Tanaya Pande
- Department of Biological Sciences, University at Buffalo, Buffalo, NY, 14260-1300, USA
| | - Mira Edgerton
- Department of Oral Biology, University at Buffalo, Buffalo, NY, 14260-1300, USA
| | - Paul J. Cullen
- Department of Biological Sciences, University at Buffalo, Buffalo, NY, 14260-1300, USA
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20
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Cordeiro RDA, Evangelista AJDJ, Serpa R, Marques FJDF, Melo CVSD, Oliveira JSD, Franco JDS, Alencar LPD, Bandeira TDJPG, Brilhante RSN, Sidrim JJC, Rocha MFG. Inhibition of heat-shock protein 90 enhances the susceptibility to antifungals and reduces the virulence of Cryptococcus neoformans/Cryptococcus gattii species complex. Microbiology (Reading) 2016; 162:309-317. [DOI: 10.1099/mic.0.000222] [Citation(s) in RCA: 42] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Affiliation(s)
- Rossana de Aguiar Cordeiro
- Specialized Medical Mycology Center,Federal University of Ceará,Fortaleza, CE, Brazil
- Postgraduate Program in Medical Sciences,Federal University of Ceará, Fortaleza, CE,Brazil
- Postgraduate Program in Medical Microbiology,Federal University of Ceará, Fortaleza, CE,Brazil
| | - Antonio José de Jesus Evangelista
- Specialized Medical Mycology Center,Federal University of Ceará,Fortaleza, CE, Brazil
- Postgraduate Program in Medical Sciences,Federal University of Ceará, Fortaleza, CE,Brazil
| | - Rosana Serpa
- Specialized Medical Mycology Center,Federal University of Ceará,Fortaleza, CE, Brazil
- Postgraduate Program in Medical Microbiology,Federal University of Ceará, Fortaleza, CE,Brazil
| | - Francisca Jakelyne de Farias Marques
- Specialized Medical Mycology Center,Federal University of Ceará,Fortaleza, CE, Brazil
- Postgraduate Program in Medical Microbiology,Federal University of Ceará, Fortaleza, CE,Brazil
| | - Charlline Vládia Silva de Melo
- Specialized Medical Mycology Center,Federal University of Ceará,Fortaleza, CE, Brazil
- Postgraduate Program in Medical Microbiology,Federal University of Ceará, Fortaleza, CE,Brazil
| | - Jonathas Sales de Oliveira
- Specialized Medical Mycology Center,Federal University of Ceará,Fortaleza, CE, Brazil
- Postgraduate Program in Medical Microbiology,Federal University of Ceará, Fortaleza, CE,Brazil
| | | | - Lucas Pereira de Alencar
- Specialized Medical Mycology Center,Federal University of Ceará,Fortaleza, CE, Brazil
- Postgraduate Program in Veterinary Sciences,State University of Ceará, Fortaleza, CE,Brazil
| | - Tereza de Jesus Pinheiro Gomes Bandeira
- Specialized Medical Mycology Center,Federal University of Ceará,Fortaleza, CE, Brazil
- School of Medicine, Christus College – UNICHRISTUS,Fortaleza, CE,Brazil
| | - Raimunda Sâmia Nogueira Brilhante
- Specialized Medical Mycology Center,Federal University of Ceará,Fortaleza, CE, Brazil
- Postgraduate Program in Medical Sciences,Federal University of Ceará, Fortaleza, CE,Brazil
- Postgraduate Program in Medical Microbiology,Federal University of Ceará, Fortaleza, CE,Brazil
| | - José Júlio Costa Sidrim
- Specialized Medical Mycology Center,Federal University of Ceará,Fortaleza, CE, Brazil
- Postgraduate Program in Medical Sciences,Federal University of Ceará, Fortaleza, CE,Brazil
- Postgraduate Program in Medical Microbiology,Federal University of Ceará, Fortaleza, CE,Brazil
| | - Marcos Fébio Gadelha Rocha
- Specialized Medical Mycology Center,Federal University of Ceará,Fortaleza, CE, Brazil
- Postgraduate Program in Medical Microbiology,Federal University of Ceará, Fortaleza, CE,Brazil
- Postgraduate Program in Veterinary Sciences,State University of Ceará, Fortaleza, CE,Brazil
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21
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Boyce KJ, Andrianopoulos A. Fungal dimorphism: the switch from hyphae to yeast is a specialized morphogenetic adaptation allowing colonization of a host. FEMS Microbiol Rev 2015; 39:797-811. [DOI: 10.1093/femsre/fuv035] [Citation(s) in RCA: 131] [Impact Index Per Article: 14.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 07/02/2015] [Indexed: 01/19/2023] Open
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22
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Lu Y, Su C, Liu H. Candida albicans hyphal initiation and elongation. Trends Microbiol 2014; 22:707-14. [PMID: 25262420 DOI: 10.1016/j.tim.2014.09.001] [Citation(s) in RCA: 134] [Impact Index Per Article: 13.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2014] [Revised: 08/28/2014] [Accepted: 09/03/2014] [Indexed: 01/01/2023]
Abstract
The fungus Candida albicans is a benign member of the mucosal microbiota, but can cause mucosal infections and life-threatening disseminated invasive infections in susceptible individuals. The ability to switch between yeast, pseudohyphal, and hyphal growth forms (polymorphism) is one of the most investigated virulence attributes of C. albicans. Recent studies suggest that hyphal development in C. albicans requires two temporally linked regulations for initiation and maintenance of the hyphal transcriptional program. Hyphal initiation requires a rapid but temporary disappearance of the Nrg1 transcriptional repressor of hyphal morphogenesis. Hyphal maintenance requires active sensing of the surrounding environment, leading to exclusion of Nrg1 binding to promoters of hypha-specific genes or reduced NRG1 expression. We discuss recent advances in understanding the complex transcriptional regulation of hyphal gene expression. These provide molecular mechanisms underpinning the phenotypic plasticity of C. albicans polymorphism.
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Affiliation(s)
- Yang Lu
- Department of Biological Chemistry, University of California, Irvine, CA 92697, USA
| | - Chang Su
- Department of Biological Chemistry, University of California, Irvine, CA 92697, USA
| | - Haoping Liu
- Department of Biological Chemistry, University of California, Irvine, CA 92697, USA.
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23
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Lamoth F, Juvvadi PR, Steinbach WJ. Heat shock protein 90 (Hsp90): A novel antifungal target against Aspergillus fumigatus. Crit Rev Microbiol 2014; 42:310-21. [PMID: 25243616 DOI: 10.3109/1040841x.2014.947239] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
Invasive aspergillosis is a life-threatening and difficult to treat infection in immunosuppressed patients. The efficacy of current anti-Aspergillus therapies, targeting the cell wall or membrane, is limited by toxicity (polyenes), fungistatic activity and some level of basal resistance (echinocandins), or the emergence of acquired resistance (triazoles). The heat shock protein 90 (Hsp90) is a conserved molecular chaperone involved in the rapid development of antifungal resistance in the yeast Candida albicans. Few studies have addressed its role in filamentous fungi such as Aspergillus fumigatus, in which mechanisms of resistance may differ substantially. Hsp90 is at the center of a complex network involving calcineurin, lysine deacetylases (KDAC) and other client proteins, which orchestrate compensatory repair mechanisms of the cell wall in response to the stress induced by antifungals. In A. fumigatus, Hsp90 is a trigger for resistance to high concentrations of caspofungin, known as the paradoxical effect. Disrupting Hsp90 circuitry by different means (Hsp90 inhibitors, KDAC inhibitors and anti-calcineurin drugs) potentiates the antifungal activity of caspofungin, thus representing a promising novel antifungal approach. This review will discuss the specific features of A. fumigatus Hsp90 and the potential for antifungal strategies of invasive aspergillosis targeting this essential chaperone.
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Affiliation(s)
- Frédéric Lamoth
- a Division of Pediatric Infectious Diseases, Department of Pediatrics , Duke University Medical Center , Durham , NC , USA .,b Infectious Diseases Service, Department of Medicine , Lausanne University Hospital , Lausanne , Switzerland .,c Institute of Microbiology, Lausanne University Hospital , Lausanne , Switzerland , and
| | - Praveen R Juvvadi
- a Division of Pediatric Infectious Diseases, Department of Pediatrics , Duke University Medical Center , Durham , NC , USA
| | - William J Steinbach
- a Division of Pediatric Infectious Diseases, Department of Pediatrics , Duke University Medical Center , Durham , NC , USA .,d Department of Molecular Genetics and Microbiology , Duke University Medical Center , Durham , NC , USA
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24
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Lamoth F, Juvvadi PR, Steinbach WJ. Heat Shock Protein 90 (Hsp90) in Fungal Growth and Pathogenesis. CURRENT FUNGAL INFECTION REPORTS 2014. [DOI: 10.1007/s12281-014-0195-9] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
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25
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Wang Y, Xu S, Liu J, Zhang Y, Guo TL. Regulation of lead toxicity by heat shock protein 90 (daf-21) is affected by temperature in Caenorhabditis elegans. ECOTOXICOLOGY AND ENVIRONMENTAL SAFETY 2014; 104:317-322. [PMID: 24726945 DOI: 10.1016/j.ecoenv.2014.03.016] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/27/2013] [Revised: 03/11/2014] [Accepted: 03/15/2014] [Indexed: 06/03/2023]
Abstract
In the nematode Caenorhabditis elegans, stress resistance can be regulated by dauer formation (daf) genes. In the present study, regulation of heavy metal lead (Pb) toxicity by the 90-kDa heat shock proteins (Hsp90; daf-21) was investigated in both wild-type C. elegans and daf-21/Hsp90 mutants by focusing on the effects of varied temperatures below (15°C) or above (25 and 30°C) the presumptive optimum growth temperature (20°C). More acute toxicity of Pb, indicated by the 24-h median lethal concentrations (LC50), was observed in wild-type adults than in the daf-21 mutant adults at 15, 20 and 25°C; however, the daf-21 mutant adults showed more sensitivity at 30°C. Enhanced Pb sensitivity (e.g., decrease LC50) in both types of C. elegans was observed with both increased and decreased temperatures when compared to that at 20°C. Additional examined endpoints included time course of toxicity at LC50s, pharyngeal pumping, reproduction, life span, and Hsp90 expression. Collective results showed that temperatures both above and below 20°C exacerbated Pb toxicity, and that the protein level of daf-21/Hsp90 was one of the most sensitive indicators of Pb toxicity in wild-type C. elegans, while pharyngeal pumping was more Pb sensitive in daf-21 mutants. Therefore, the expression of daf-21/Hsp90 has apparent utility for the prediction and assessment of Pb-induced toxicity in nematodes. Further, the stress responses related to Hsp90 expression in C. elegans may have considerable potential as sensitive biomarkers for the monitoring of environmental Pb contamination.
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Affiliation(s)
- Yunbiao Wang
- Key Laboratory of Wetland Ecology and Environment, Northeast Institute of Geography and Agroecology, Chinese Academy of Sciences, Changchun 130102, China; Department of Veterinary Biosciences and Diagnostic Imaging, College of Veterinary Medicine, University of Georgia, Athens, GA 30602-7382, USA
| | - Songbai Xu
- Department of Neurosurgery, First Hospital, Jilin University, Changchun 130021, China
| | - Jing Liu
- Key Laboratory of Wetland Ecology and Environment, Northeast Institute of Geography and Agroecology, Chinese Academy of Sciences, Changchun 130102, China
| | - Yanhui Zhang
- Key Laboratory of Wetland Ecology and Environment, Northeast Institute of Geography and Agroecology, Chinese Academy of Sciences, Changchun 130102, China
| | - Tai L Guo
- Department of Veterinary Biosciences and Diagnostic Imaging, College of Veterinary Medicine, University of Georgia, Athens, GA 30602-7382, USA.
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26
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Nageshan RK, Roy N, Ranade S, Tatu U. Trans-spliced heat shock protein 90 modulates encystation in Giardia lamblia. PLoS Negl Trop Dis 2014; 8:e2829. [PMID: 24786776 PMCID: PMC4006730 DOI: 10.1371/journal.pntd.0002829] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/24/2013] [Accepted: 03/13/2014] [Indexed: 01/22/2023] Open
Abstract
Background Hsp90 from Giardia lamblia is expressed by splicing of two independently transcribed RNA molecules, coded by genes named HspN and HspC located 777 kb apart. The reasons underlying such unique trans-splicing based generation of GlHsp90 remain unclear. Principle Finding In this study using mass-spectrometry we identify the sequence of the unique, junctional peptide contributed by the 5′ UTR of HspC ORF. This peptide is critical for the catalytic function of Hsp90 as it harbours an essential “Arg” in its sequence. We also show that full length GlHsp90 possesses all the functional hall marks of a canonical Hsp90 including its ability to bind and hydrolyze ATP. Using qRT-PCR as well as western blotting approach we find the reconstructed Hsp90 to be induced in response to heat shock. On the contrary we find GlHsp90 to be down regulated during transition from proliferative trophozoites to environmentally resistant cysts. This down regulation of GlHsp90 appears to be mechanistically linked to the encystation process as we find pharmacological inhibition of GlHsp90 function to specifically induce encystation. Significance Our results implicate the trans-spliced GlHsp90 from Giardia lamblia to regulate an essential stage transition in the life cycle of this important human parasite. Giardia lamblia is one of the most common causes of diarrhoea across the globe. The disease can result in fatalities especially in small children. The parasite is transmitted by contaminated food through faeco-oral route due to unhygienic habits. The parasite exhibits two stages during its lifecycle; namely cysts and trophozoites. Due to their environmentally resistant hardy nature cysts are transmitted through contaminated food into the human body. Upon entry into the human body they convert into active trophozoites and cause pathogenesis of the disease. In the course of infection within the host, some of the trophozoites convert back into cysts and are released in the environment through the faeces. The mechanisms and signals that convert the parasite from trophozoites to cysts are not yet known. Our study, for the first time, implicates heat shock protein 90 of the parasite in the conversion of trophozoites into cysts in the intestine of the infected human body. Hsp90 is famous for its ability to sense environmental changes and provide cues for stage-switch in related parasites. In addition to providing a glimpse into molecular mechanisms of stage inter-conversion, our results suggest potential new ways of treating this important human infection.
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Affiliation(s)
| | - Nainita Roy
- The Department of Biochemistry, Indian Institute of Sciences, Bangalore, India
| | - Shatakshi Ranade
- The Department of Biochemistry, Indian Institute of Sciences, Bangalore, India
| | - Utpal Tatu
- The Department of Biochemistry, Indian Institute of Sciences, Bangalore, India
- * E-mail:
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27
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Tyc KM, Kühn C, Wilson D, Klipp E. Assessing the advantage of morphological changes in Candida albicans: a game theoretical study. Front Microbiol 2014; 5:41. [PMID: 24567730 PMCID: PMC3915147 DOI: 10.3389/fmicb.2014.00041] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2013] [Accepted: 01/21/2014] [Indexed: 12/17/2022] Open
Abstract
A range of attributes determines the virulence of human pathogens. During interactions with their hosts, pathogenic microbes often undergo transitions between distinct stages, and the ability to switch between these can be directly related to the disease process. Understanding the mechanisms and dynamics of these transitions is a key factor in understanding and combating infectious diseases. The human fungal pathogen Candida albicans exhibits different morphotypes at different stages during the course of infection (candidiasis). For example, hyphae are considered to be the invasive form, which causes tissue damage, while yeast cells are predominant in the commensal stage. Here, we described interactions of C. albicans with its human host in a game theoretic model. In the game, players are fungal cells. Each fungal cell can adopt one of the two strategies: to exist as a yeast or hyphal cell. We characterized the ranges of model parameters in which the coexistence of both yeast and hyphal forms is plausible. Stability analysis of the system showed that, in theory, a reduced ability of the host to specifically recognize yeast and hyphal cells can result in bi-stability of the microbial populations' profile. Inspired by the model analysis we reasoned that the types of microbial interactions can change during invasive candidiasis. We found that positive cooperation among fungal cells occurs in mild infections and an enhanced tendency to invade the host is associated with negative cooperation. The model can easily be extended to multi-player systems with direct application to identifying individuals that enhance either positive or negative cooperation. Results of the modeling approach have potential application in developing treatment strategies.
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Affiliation(s)
- Katarzyna M Tyc
- Department of Biology, Theoretical Biophysics, Humboldt-Universität zu Berlin Berlin, Germany
| | - Clemens Kühn
- Department of Biology, Theoretical Biophysics, Humboldt-Universität zu Berlin Berlin, Germany
| | - Duncan Wilson
- Department of Microbial Pathogenicity Mechanisms, Leibniz Institute for Natural Product Research and Infection Biology, Hans Knöll Institute Jena, Germany
| | - Edda Klipp
- Department of Biology, Theoretical Biophysics, Humboldt-Universität zu Berlin Berlin, Germany
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Alexandratos A, Clos J, Samiotaki M, Efstathiou A, Panayotou G, Soteriadou K, Smirlis D. The loss of virulence of histone H1 overexpressingLeishmania donovaniparasites is directly associated with a reduction of HSP83 rate of translation. Mol Microbiol 2013; 88:1015-31. [DOI: 10.1111/mmi.12240] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 04/15/2013] [Indexed: 01/15/2023]
Affiliation(s)
- Alexandros Alexandratos
- Laboratory of Molecular Parasitology; Department of Microbiology; Hellenic Pasteur Institute; 127 Vas Sofias Ave. Athens Greece
- Chemistry Department; University of Ioannina; Ioannina Greece
| | - Joachim Clos
- Bernhard Nocht Institute for Tropical Medicine; Hamburg Germany
| | - Martina Samiotaki
- Biomedical Sciences Research Center; ‘Alexander Fleming’; Vari Greece
| | - Antonia Efstathiou
- Laboratory of Molecular Parasitology; Department of Microbiology; Hellenic Pasteur Institute; 127 Vas Sofias Ave. Athens Greece
| | - George Panayotou
- Biomedical Sciences Research Center; ‘Alexander Fleming’; Vari Greece
| | - Ketty Soteriadou
- Laboratory of Molecular Parasitology; Department of Microbiology; Hellenic Pasteur Institute; 127 Vas Sofias Ave. Athens Greece
| | - Despina Smirlis
- Laboratory of Molecular Parasitology; Department of Microbiology; Hellenic Pasteur Institute; 127 Vas Sofias Ave. Athens Greece
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29
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Tamayo D, Muñoz JF, Torres I, Almeida AJ, Restrepo A, McEwen JG, Hernández O. Involvement of the 90 kDa heat shock protein during adaptation of Paracoccidioides brasiliensis to different environmental conditions. Fungal Genet Biol 2012. [PMID: 23207691 DOI: 10.1016/j.fgb.2012.11.005] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
HSP90 is a molecular chaperone that participates in folding, stabilization, activation, and assembly of several proteins, all of which are key regulators in cell signaling. In dimorphic pathogenic fungi such as Paracoccidioides brasiliensis, the adaptation to a higher temperature, acid pH and oxidative stress, is an essential event for fungal survival and also for the establishing of the infectious process. To further understand the role of this protein, we used antisense RNA technology to generate a P. brasiliensis isolate with reduced PbHSP90 gene expression (PbHSP90-aRNA). Reduced expression of HSP90 decreased yeast cell viability during batch culture growth and increased susceptibility to acid pH environments and imposed oxidative stress. Also, PbHSP90-aRNA yeast cells presented reduced viability upon interaction with macrophages. The findings presented here suggest a protective role for HSP90 during adaptation to hostile environments, one that promotes survival of the fungus during host-pathogen interactions.
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Affiliation(s)
- Diana Tamayo
- Unidad de Biología Celular y Molecular, Corporación para Investigaciones Biológicas, Medellín, Colombia
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Biology of the heat shock response and protein chaperones: budding yeast (Saccharomyces cerevisiae) as a model system. Microbiol Mol Biol Rev 2012; 76:115-58. [PMID: 22688810 DOI: 10.1128/mmbr.05018-11] [Citation(s) in RCA: 362] [Impact Index Per Article: 30.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023] Open
Abstract
The eukaryotic heat shock response is an ancient and highly conserved transcriptional program that results in the immediate synthesis of a battery of cytoprotective genes in the presence of thermal and other environmental stresses. Many of these genes encode molecular chaperones, powerful protein remodelers with the capacity to shield, fold, or unfold substrates in a context-dependent manner. The budding yeast Saccharomyces cerevisiae continues to be an invaluable model for driving the discovery of regulatory features of this fundamental stress response. In addition, budding yeast has been an outstanding model system to elucidate the cell biology of protein chaperones and their organization into functional networks. In this review, we evaluate our understanding of the multifaceted response to heat shock. In addition, the chaperone complement of the cytosol is compared to those of mitochondria and the endoplasmic reticulum, organelles with their own unique protein homeostasis milieus. Finally, we examine recent advances in the understanding of the roles of protein chaperones and the heat shock response in pathogenic fungi, which is being accelerated by the wealth of information gained for budding yeast.
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31
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Matos TGF, Morais FV, Campos CBL. Hsp90 regulates Paracoccidioides brasiliensis proliferation and ROS levels under thermal stress and cooperates with calcineurin to control yeast to mycelium dimorphism. Med Mycol 2012; 51:413-21. [PMID: 23013413 DOI: 10.3109/13693786.2012.725481] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
Paracoccidioidomycosis is a systemic human mycosis in Latin America caused by Paracoccidioides brasiliensis, a dimorphic pathogenic fungus that lives as a mold in the environment and as yeast during infections of human lungs. In this work, we provide evidence that the inhibition of Hsp90 by geldanamycin (GDA) impairs the proliferation of the yeast, but has no effect on mycelial development. Treatment with cyclosporin A (CsA), an inhibitor of the Hsp90 client protein calcineurin, did not increase the effect of GDA. In contrast, GDA prevented mycelial to yeast differentiation through a mechanism partially dependent on calcineurin, whereas differentiation from yeast to mycelia occurred independent of GDA or CsA. A significant increase in reactive oxygen species (ROS) levels was detected in GDA-treated yeast at 42°C. However, the levels of ROS remained unchanged in GDA-treated yeast or mycelia incubated at 37°C, suggesting that Hsp90 plays different roles under normal and thermal stress conditions. We propose that Hsp90 strengthens the stress response of P. brasiliensis at 37°C through a mechanism that does not involve ROS. Moreover, we suggest that Hsp90 has calcineurin-dependent functions in this organism.
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Affiliation(s)
- Tatiana G F Matos
- Instituto de Pesquisa e Desenvolvimento , Universidade do Vale do ParaiIba UNIVAP, São Jose dos Campos, São Paulo, Brazil
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Jacobsen ID, Wilson D, Wächtler B, Brunke S, Naglik JR, Hube B. Candida albicans dimorphism as a therapeutic target. Expert Rev Anti Infect Ther 2012; 10:85-93. [PMID: 22149617 DOI: 10.1586/eri.11.152] [Citation(s) in RCA: 241] [Impact Index Per Article: 20.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
The ability to switch between yeast and hyphal growth forms (dimorphism) is one of the most discussed and best investigated virulence attributes of the human pathogenic fungus Candida albicans. Both morphological forms seem to be important for virulence and have distinct functions during the different stages of disease development, including adhesion, invasion, damage, dissemination, immune evasion and host response. In this review, we will provide an overview of the known and potential roles of C. albicans dimorphism and will discuss the potential benefit of drugs that can inhibit the morphological transition.
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Affiliation(s)
- Ilse D Jacobsen
- Department of Microbial Pathogenicity Mechanisms, Leibniz Institute for Natural Product Research and Infection Biology-Hans Knoell Institute Jena, Beutenbergstraße 11a, D-07745, Jena, Germany
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Pedras MSC, Minic Z. Differential protein expression in response to the phytoalexin brassinin allows the identification of molecular targets in the phytopathogenic fungus Alternaria brassicicola. MOLECULAR PLANT PATHOLOGY 2012; 13:483-93. [PMID: 22111639 PMCID: PMC6638890 DOI: 10.1111/j.1364-3703.2011.00765.x] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/21/2023]
Abstract
The effects of the cruciferous phytoalexin brassinin on the protein expression patterns of the phytopathogenic fungus Alternaria brassicicola were investigated. Cell-free protein extracts of mycelia of A. brassicicola induced with brassinin at 0.50 and 0.10 mm were fractionated, and the proteins in soluble fractions were separated by two-dimensional electrophoresis. Spots corresponding to differentially expressed proteins were digested and analysed by liquid chromatography-electrospray ionization-mass spectrometry. The number of differentially expressed proteins was significantly higher in mycelia treated with brassinin at 0.50 mm (96 protein spots) than in mycelia treated with brassinin at 0.10 mm (18 protein spots). The majority of differentially expressed proteins included proteins involved in metabolism, processing, synthesis and several heat shock proteins (HSPs). Brassinin concentrations below 0.30 mm induced HSP90, a protein involved in the regulation of morphogenetic signalling in fungi, suggesting that 0.30 mm is a minimal concentration of brassinin necessary for the protection of brassicas against A. brassicicola. These results reveal that HSP90 is a potential target for inhibition in stressed A. brassicicola and confirm that brassinin has strong detrimental effects on A. brassicicola, suggesting that its detoxification by the fungus suppresses an important defence layer of the plant.
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Affiliation(s)
- M Soledade C Pedras
- Department of Chemistry, University of Saskatchewan, Saskatoon, SK, Canada, S7N 5C9
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34
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Fuller KK, Rhodes JC. Protein kinase A and fungal virulence: a sinister side to a conserved nutrient sensing pathway. Virulence 2012; 3:109-21. [PMID: 22460637 PMCID: PMC3396691 DOI: 10.4161/viru.19396] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
Diverse fungal species are the cause of devastating agricultural and human diseases. As successful pathogenesis is dependent upon the ability of the fungus to adapt to the nutritional and chemical environment of the host, the understanding of signaling pathways required for such adaptation will provide insights into the virulence of these pathogens and the potential identification of novel targets for antifungal intervention. The cAMP-PKA signaling pathway is well conserved across eukaryotes. In the nonpathogenic yeast, S. cerevisiae, PKA is activated in response to extracellular nutrients and subsequently regulates metabolism and growth. Importantly, this pathway is also a regulator of pathogenesis, as defects in PKA signaling lead to an attenuation of virulence in diverse plant and human pathogenic fungi. This review will compare and contrast PKA signaling in S. cerevisiae vs. various pathogenic species and provide a framework for the role of this pathway in regulating fungal virulence.
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Affiliation(s)
- Kevin K Fuller
- Department of Pathology, University of Cincinnati College of Medicine, Cincinnati, OH, USA.
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35
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Roy N, Nageshan RK, Ranade S, Tatu U. Heat shock protein 90 from neglected protozoan parasites. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2011; 1823:707-11. [PMID: 22198098 DOI: 10.1016/j.bbamcr.2011.12.003] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/29/2011] [Revised: 12/06/2011] [Accepted: 12/06/2011] [Indexed: 01/15/2023]
Abstract
Significant advances have been made in our understanding of heat shock protein 90 (Hsp90) in terms of its structure, biochemical characteristics, post-translational modifications, interactomes, regulation and functions. In addition to yeast as a model several new systems have now been examined including flies, worms, plants as well as mammalian cells. This review discusses themes emerging out of studies reported on Hsp90 from infectious disease causing protozoa. A common theme of sensing and responding to host cell microenvironment emerges out of analysis of Hsp90 in Malaria, Trypanosmiasis as well as Leishmaniasis. In addition to their functional roles, the potential of Hsp90 from these infectious disease causing organisms to serve as drug targets and the current status of this drug development endeavor are discussed. Finally, a unique and the only known example of a split Hsp90 gene from another disease causing protozoan Giardia lamblia and its evolutionary significance are discussed. Clearly studies on Hsp90 from protozoan parasites promise to reveal important new paradigms in Hsp90 biology while exploring its potential as an anti-infective drug target. This article is part of a Special Issue entitled: Heat Shock Protein 90 (HSP90).
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Affiliation(s)
- Nainita Roy
- Department of Biochemistry, Indian Institute of Science, Bangalore, India
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36
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Chen SCA, Lewis RE, Kontoyiannis DP. Direct effects of non-antifungal agents used in cancer chemotherapy and organ transplantation on the development and virulence of Candida and Aspergillus species. Virulence 2011; 2:280-95. [PMID: 21701255 PMCID: PMC3173675 DOI: 10.4161/viru.2.4.16764] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2011] [Revised: 06/01/2011] [Accepted: 06/03/2011] [Indexed: 11/19/2022] Open
Abstract
Conventional antineoplastic, novel immunosuppressive agents and antibiotics used in cancer treatment can directly affect the growth, development and virulence of Candida and Aspergillus species. Cytotoxic and cisplatin compounds have anti-Candida activity and may be synergistic with antifungal drugs; they also inhibit Candida and Aspergillus filamentation/conidation and effect increased virulence in vitro. Glucocorticoids enhance Candida adherence to epithelial cells, germination in serum and in vitro secretion of phospholipases and proteases, as well as growth of A. fumigatus. Calcineurin and target of rapamycin inhibitors perturb Candida and Aspergillus morphogenesis, stress responses and survival in serum, reduce azole tolerance in Candida, but yield conflicting in vivo data. Inhibition of candidal heat shock protein 90 and candidal-specific histone deacetylase represent feasible therapeutic approaches for candidiasis. Tyrosine kinase inhibitors inhibit fungal cell entry into epithelial cells and phagocytosis. Quinolone and other antibiotics may augment activity of azole and polyene agents. The correlation of in vitro effects with clinically meaningful in vivo systems is warranted.
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Affiliation(s)
- Sharon C-A Chen
- Centre for Infectious Diseases and Microbiology, Westmead Hospital, University of Sydney, Westmead, NSW Australia
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37
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Modulation of morphogenesis in Candida albicans by various small molecules. EUKARYOTIC CELL 2011; 10:1004-12. [PMID: 21642508 DOI: 10.1128/ec.05030-11] [Citation(s) in RCA: 90] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
The pathogenic yeast Candida albicans, a member of the mucosal microbiota, is responsible for a large spectrum of infections, ranging from benign thrush and vulvovaginitis in both healthy and immunocompromised individuals to severe, life-threatening infections in immunocompromised patients. A striking feature of C. albicans is its ability to grow as budding yeast and as filamentous forms, including hyphae and pseudohyphae. The yeast-to-hypha transition contributes to the overall virulence of C. albicans and may even constitute a target for the development of antifungal drugs. Indeed, impairing morphogenesis in C. albicans has been shown to be a means to treat candidiasis. Additionally, a large number of small molecules such as farnesol, fatty acids, rapamycin, geldanamycin, histone deacetylase inhibitors, and cell cycle inhibitors have been reported to modulate the yeast-to-hypha transition in C. albicans. In this minireview, we take a look at molecules that modulate morphogenesis in this pathogenic yeast. When possible, we address experimental findings regarding their mechanisms of action and their therapeutic potential. We discuss whether or not modulating morphogenesis constitutes a strategy to treat Candida infections.
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38
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Brown AJP, Leach MD, Nicholls S. The relevance of heat shock regulation in fungal pathogens of humans. Virulence 2011; 1:330-2. [PMID: 21178465 DOI: 10.4161/viru.1.4.12364] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023] Open
Abstract
Despite being obligately associated with warm-blooded animals, Candida albicans expresses a bona fide heat shock response that is regulated by the evolutionarily conserved, essential heat shock transcription factor Hsf1. Hsf1 is thought to play a fundamental role in thermal homeostasis, adjusting the levels of essential chaperones to changes in growth temperature, for example in febrile patients. Hsf1 also regulates the expression of Hsp90, which controls the yeast-hypha transition in C. albicans, and we argue, might also control morphogenesis in other fungal pathogens of humans.
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Affiliation(s)
- Alistair J P Brown
- Aberdeen Fungal Group, School of Medical Sciences, University of Aberdeen, Aberdeen, UK.
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39
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Guimarães AJ, Nakayasu ES, Sobreira TJP, Cordero RJB, Nimrichter L, Almeida IC, Nosanchuk JD. Histoplasma capsulatum heat-shock 60 orchestrates the adaptation of the fungus to temperature stress. PLoS One 2011; 6:e14660. [PMID: 21347364 PMCID: PMC3037374 DOI: 10.1371/journal.pone.0014660] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2010] [Accepted: 01/13/2011] [Indexed: 01/06/2023] Open
Abstract
Heat shock proteins (Hsps) are among the most widely distributed and evolutionary conserved proteins. Hsps are essential regulators of diverse constitutive metabolic processes and are markedly upregulated during stress. A 62 kDa Hsp (Hsp60) of Histoplasma capsulatum (Hc) is an immunodominant antigen and the major surface ligand to CR3 receptors on macrophages. However little is known about the function of this protein within the fungus. We characterized Hc Hsp60-protein interactions under different temperature to gain insights of its additional functions oncell wall dynamism, heat stress and pathogenesis. We conducted co-immunoprecipitations with antibodies to Hc Hsp60 using cytoplasmic and cell wall extracts. Interacting proteins were identified by shotgun proteomics. For the cell wall, 84 common interactions were identified among the 3 growth conditions, including proteins involved in heat-shock response, sugar and amino acid/protein metabolism and cell signaling. Unique interactions were found at each temperature [30°C (81 proteins), 37°C (14) and 37/40°C (47)]. There were fewer unique interactions in cytoplasm [30°C (6), 37°C (25) and 37/40°C (39)] and four common interactions, including additional Hsps and other known virulence factors. These results show the complexity of Hsp60 function and provide insights into Hc biology, which may lead to new avenues for the management of histoplasmosis.
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Affiliation(s)
- Allan Jefferson Guimarães
- Division of Infectious Diseases, Department of Medicine, Albert Einstein College of Medicine of Yeshiva University, Bronx, New York, United States of America
- Department of Microbiology and Immunology, Albert Einstein College of Medicine of Yeshiva University, Bronx, New York, United States of America
| | - Ernesto S. Nakayasu
- Pacific Northwest National Laboratory, Richland, Washington, United States of America
| | - Tiago J. P. Sobreira
- Group of Computational Biology, Laboratory of Genetics and Molecular Cardiology, Heart Institute (InCor), São Paulo, Brazil
| | - Radames J. B. Cordero
- Department of Microbiology and Immunology, Albert Einstein College of Medicine of Yeshiva University, Bronx, New York, United States of America
| | - Leonardo Nimrichter
- Laboratório de Estudos Integrados em Bioquímica Microbiana, Instituto de Microbiologia Professor Paulo de Góes, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brazil
| | - Igor C. Almeida
- Department of Biological Sciences, The Border Biomedical Research Center, University of Texas at El Paso, El Paso, Texas, United States of America
| | - Joshua Daniel Nosanchuk
- Division of Infectious Diseases, Department of Medicine, Albert Einstein College of Medicine of Yeshiva University, Bronx, New York, United States of America
- Department of Microbiology and Immunology, Albert Einstein College of Medicine of Yeshiva University, Bronx, New York, United States of America
- * E-mail:
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