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McCrory C, Lenardon M, Traven A. Bacteria-derived short-chain fatty acids as potential regulators of fungal commensalism and pathogenesis. Trends Microbiol 2024:S0966-842X(24)00089-1. [PMID: 38729839 DOI: 10.1016/j.tim.2024.04.004] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2024] [Revised: 04/08/2024] [Accepted: 04/16/2024] [Indexed: 05/12/2024]
Abstract
The human gastrointestinal microbiome encompasses bacteria, fungi, and viruses forming complex bionetworks which, for organismal health, must be in a state of homeostasis. An important homeostatic mechanism derives from microbial competition, which maintains the relative abundance of microbial species in a healthy balance. Microbes compete for nutrients and secrete metabolites that inhibit other microbes. Short-chain fatty acids (SCFAs) are one such class of metabolites made by gut bacteria to very high levels. SCFAs are metabolised by microbes and host cells and have multiple roles in regulating cell physiology. Here, we review the mechanisms by which SCFAs regulate the fungal gut commensal Candida albicans. We discuss SCFA's ability to inhibit fungal growth, limit invasive behaviours and modulate cell surface antigens recognised by immune cells. We review the mechanisms underlying these roles: regulation of gene expression, metabolism, signalling and SCFA-driven post-translational protein modifications by acylation, which contribute to changes in acylome dynamics of C. albicans with potentially large consequences for cell physiology. Given that the gut mycobiome is a reservoir for systemic disease and has also been implicated in inflammatory bowel disease, understanding the mechanisms by which bacterial metabolites, such as SCFAs, control the mycobiome might provide therapeutic avenues.
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Affiliation(s)
- Christopher McCrory
- Department of Biochemistry and Molecular Biology, Infection Program, Biomedicine Discovery Institute, Monash University, Clayton 3800, Victoria, Australia; Centre to Impact AMR, Monash University, Clayton 3800, Victoria, Australia
| | - Megan Lenardon
- School of Biotechnology and Biomolecular Sciences, University of New South Wales, Sydney, 2052, New South Wales, Australia
| | - Ana Traven
- Department of Biochemistry and Molecular Biology, Infection Program, Biomedicine Discovery Institute, Monash University, Clayton 3800, Victoria, Australia; Centre to Impact AMR, Monash University, Clayton 3800, Victoria, Australia.
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2
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Lo TL, Wang Q, Nickson J, van Denderen BJW, Deveson Lucas D, Chai HX, Knott GJ, Weerasinghe H, Traven A. The C-terminal protein interaction domain of the chromatin reader Yaf9 is critical for pathogenesis of Candida albicans. mSphere 2024; 9:e0069623. [PMID: 38376217 DOI: 10.1128/msphere.00696-23] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2023] [Accepted: 01/26/2024] [Indexed: 02/21/2024] Open
Abstract
Fungal infections cause a large health burden but are treated by only a handful of antifungal drug classes. Chromatin factors have emerged as possible targets for new antifungals. These targets include the reader proteins, which interact with posttranslationally modified histones to influence DNA transcription and repair. The YEATS domain is one such reader recognizing both crotonylated and acetylated histones. Here, we performed a detailed structure/function analysis of the Candida albicans YEATS domain reader Yaf9, a subunit of the NuA4 histone acetyltransferase and the SWR1 chromatin remodeling complex. We have previously demonstrated that the homozygous deletion mutant yaf9Δ/Δ displays growth defects and is avirulent in mice. Here we show that a YEATS domain mutant expected to inactivate Yaf9's chromatin binding does not display strong phenotypes in vitro, nor during infection of immune cells or in a mouse systemic infection model, with only a minor virulence reduction in vivo. In contrast to the YEATS domain mutation, deletion of the C-terminal domain of Yaf9, a protein-protein interaction module necessary for its interactions with SWR1 and NuA4, phenocopies the null mutant. This shows that the C-terminal domain is essential for Yaf9 roles in vitro and in vivo, including C. albicans virulence. Our study informs on the strategies for therapeutic targeting of Yaf9, showing that approaches taken for the mammalian YEATS domains by disrupting their chromatin binding might not be effective in C. albicans, and provides a foundation for studying YEATS proteins in human fungal pathogens.IMPORTANCEThe scarcity of available antifungal drugs and rising resistance demand the development of therapies with new modes of action. In this context, chromatin regulation may be a target for novel antifungal therapeutics. To realize this potential, we must better understand the roles of chromatin regulators in fungal pathogens. Toward this goal, here, we studied the YEATS domain chromatin reader Yaf9 in Candida albicans. Yaf9 uses the YEATS domain for chromatin binding and a C-terminal domain to interact with chromatin remodeling complexes. By constructing mutants in these domains and characterizing their phenotypes, our data indicate that the Yaf9 YEATS domain might not be a suitable therapeutic drug target. Instead, the Yaf9 C-terminal domain is critical for C. albicans virulence. Collectively, our study informs how a class of chromatin regulators performs their cellular and pathogenesis roles in C. albicans and reveals strategies to inhibit them.
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Affiliation(s)
- Tricia L Lo
- Department of Biochemistry and Molecular Biology and the Infection Program, Biomedicine Discovery Institute, Monash University, Clayton, Australia
- Centre to Impact AMR, Monash University, Clayton, Australia
| | - Qi Wang
- Department of Biochemistry and Molecular Biology and the Infection Program, Biomedicine Discovery Institute, Monash University, Clayton, Australia
| | - Joshua Nickson
- Centre to Impact AMR, Monash University, Clayton, Australia
| | - Bryce J W van Denderen
- Department of Biochemistry and Molecular Biology and the Infection Program, Biomedicine Discovery Institute, Monash University, Clayton, Australia
- Centre to Impact AMR, Monash University, Clayton, Australia
| | | | - Her Xiang Chai
- Department of Biochemistry and Molecular Biology and the Infection Program, Biomedicine Discovery Institute, Monash University, Clayton, Australia
| | - Gavin J Knott
- Department of Biochemistry and Molecular Biology and the Infection Program, Biomedicine Discovery Institute, Monash University, Clayton, Australia
| | - Harshini Weerasinghe
- Department of Biochemistry and Molecular Biology and the Infection Program, Biomedicine Discovery Institute, Monash University, Clayton, Australia
- Centre to Impact AMR, Monash University, Clayton, Australia
| | - Ana Traven
- Department of Biochemistry and Molecular Biology and the Infection Program, Biomedicine Discovery Institute, Monash University, Clayton, Australia
- Centre to Impact AMR, Monash University, Clayton, Australia
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Olivier FAB, Traven A. Quantitative live-cell imaging of Candida albicans escape from immune phagocytes. STAR Protoc 2023; 4:102737. [PMID: 37980567 PMCID: PMC10694764 DOI: 10.1016/j.xpro.2023.102737] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2023] [Revised: 10/04/2023] [Accepted: 11/02/2023] [Indexed: 11/21/2023] Open
Abstract
Population-level dynamics of host-pathogen interactions can be characterized using quantitative live-cell imaging. Here, we present a protocol for infecting macrophages with the fungal pathogen Candida albicans in vitro and quantitative live-cell imaging of immune and pathogen responses. We describe steps for detailed image analysis and provide resources for quantification of phagocytosis and pathogen escape, as well as macrophage membrane permeabilization and viability. This protocol is modifiable for applications with a range of pathogens, immune cell types, and host-pathogen mechanisms. For complete details on the use and execution of this protocol, please refer to Olivier et al.1.
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Affiliation(s)
- Françios A B Olivier
- Infection Program, Department of Biochemistry and Molecular Biology, Biomedicine Discovery Institute, Monash University, Clayton, VIC 3800, Australia; Centre to Impact AMR, Monash University, Clayton, VIC 3800, Australia.
| | - Ana Traven
- Infection Program, Department of Biochemistry and Molecular Biology, Biomedicine Discovery Institute, Monash University, Clayton, VIC 3800, Australia; Centre to Impact AMR, Monash University, Clayton, VIC 3800, Australia.
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McCrory C, Verma J, Tucey TM, Turner R, Weerasinghe H, Beilharz TH, Traven A. The short-chain fatty acid crotonate reduces invasive growth and immune escape of Candida albicans by regulating hyphal gene expression. mBio 2023; 14:e0260523. [PMID: 37929941 PMCID: PMC10746253 DOI: 10.1128/mbio.02605-23] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2023] [Accepted: 10/02/2023] [Indexed: 11/07/2023] Open
Abstract
Microbes are exposed to nutritional and stress challenges in their environmental and host niches. To rise to these challenges, they regulate transcriptional programs that enable cellular adaptation. For instance, metabolite concentrations regulate post-translational modifications of chromatin, such as histone acetylation. In this way, metabolic signals are integrated with transcription. Over the last decade, several histone acylations have been discovered, including histone crotonylation. Their roles in microbial biology, environmental adaptation, and microbe-host interactions are incompletely defined. Here we show that the short-chain fatty acid crotonate, which is used to study histone crotonylation, changes cell morphology and immune interactions of Candida albicans. Crotonate reduces invasive hyphal morphogenesis of C. albicans within macrophages, thereby delaying macrophage killing and pathogen escape, as well as reducing inflammatory cytokine maturation. Crotonate's ability to reduce hyphal growth is environmentally contingent and pronounced within macrophages. Moreover, crotonate is a stronger hyphal inhibitor than butyrate under the conditions that we tested. Crotonate causes increased histone crotonylation in C. albicans under hyphal growth conditions and reduces transcription of hyphae-induced genes in a manner that involves the Nrg1 repressor pathway. Increasing histone acetylation by histone deacetylase inhibition partially rescues hyphal growth and gene transcription in the presence of crotonate. These results indicate that histone crotonylation might compete with acetylation in the regulation of hyphal morphogenesis. Based on our findings, we propose that diverse acylations of histones (and likely also non-histone proteins) enable C. albicans to respond to environmental signals, which in turn regulate its cell morphology and host-pathogen interactions.IMPORTANCEMacrophages curtail the proliferation of the pathogen Candida albicans within human body niches. Within macrophages, C. albicans adapts its metabolism and switches to invasive hyphal morphology. These adaptations enable fungal growth and immune escape by triggering macrophage lysis. Transcriptional programs regulate these metabolic and morphogenetic adaptations. Here we studied the roles of chromatin in these processes and implicate lysine crotonylation, a histone mark regulated by metabolism, in hyphal morphogenesis and macrophage interactions by C. albicans. We show that the short-chain fatty acid crotonate increases histone crotonylation, reduces hyphal formation within macrophages, and slows macrophage lysis and immune escape of C. albicans. Crotonate represses hyphal gene expression, and we propose that C. albicans uses diverse acylation marks to regulate its cell morphology in host environments. Hyphal formation is a virulence property of C. albicans. Therefore, a further importance of our study stems from identifying crotonate as a hyphal inhibitor.
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Affiliation(s)
- Christopher McCrory
- Department of Biochemistry and Molecular Biology and Infection Program, Biomedicine Discovery Institute, Monash University, Clayton, Australia
- Centre to Impact AMR, Monash University, Clayton, Australia
| | - Jiyoti Verma
- Department of Biochemistry and Molecular Biology and Infection Program, Biomedicine Discovery Institute, Monash University, Clayton, Australia
| | - Timothy M. Tucey
- Department of Biochemistry and Molecular Biology and Infection Program, Biomedicine Discovery Institute, Monash University, Clayton, Australia
| | - Rachael Turner
- Department of Biochemistry and Molecular Biology and Stem Cells and Development Program, Biomedicine Discovery Institute, Monash University, Clayton, Australia
| | - Harshini Weerasinghe
- Department of Biochemistry and Molecular Biology and Infection Program, Biomedicine Discovery Institute, Monash University, Clayton, Australia
- Centre to Impact AMR, Monash University, Clayton, Australia
| | - Traude H. Beilharz
- Department of Biochemistry and Molecular Biology and Infection Program, Biomedicine Discovery Institute, Monash University, Clayton, Australia
- Department of Biochemistry and Molecular Biology and Stem Cells and Development Program, Biomedicine Discovery Institute, Monash University, Clayton, Australia
| | - Ana Traven
- Department of Biochemistry and Molecular Biology and Infection Program, Biomedicine Discovery Institute, Monash University, Clayton, Australia
- Centre to Impact AMR, Monash University, Clayton, Australia
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Pan B, Weerasinghe H, Sezmis A, McDonald MJ, Traven A, Thompson P, Simm C. Leveraging the MMV Pathogen Box to Engineer an Antifungal Compound with Improved Efficacy and Selectivity against Candida auris. ACS Infect Dis 2023; 9:1901-1917. [PMID: 37756147 DOI: 10.1021/acsinfecdis.3c00199] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 09/29/2023]
Abstract
Fungal infections pose a significant and increasing threat to human health, but the current arsenal of antifungal drugs is inadequate. We screened the Medicines for Malaria Venture (MMV) Pathogen Box for new antifungal agents against three of the most critical Candida species (Candida albicans, Candida auris, and Candida glabrata). Of the 14 identified hit compounds, most were active against C. albicans and C. auris. We selected the pyrazolo-pyrimidine MMV022478 for chemical modifications to build structure-activity relationships and study their antifungal properties. Two analogues, 7a and 8g, with distinct fluorine substitutions, greatly improved the efficacy against C. auris and inhibited fungal replication inside immune cells. Additionally, analogue 7a had improved selectivity toward fungal killing compared to mammalian cytotoxicity. Evolution experiments generating MMV022478-resistant isolates revealed a change in morphology from oblong to round cells. Most notably, the resistant isolates blocked the uptake of the fluorescent dye rhodamine 6G and showed reduced susceptibility toward fluconazole, indicative of structural changes in the yeast cell surface. In summary, our study identified a promising antifungal compound with activity against high-priority fungal pathogens. Additionally, we demonstrated how structure-activity relationship studies of known and publicly available compounds can expand the repertoire of molecules with antifungal efficacy and reduced cytotoxicity to drive the development of novel therapeutics.
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Affiliation(s)
- Baolong Pan
- Monash Institute of Pharmaceutical Sciences, Monash University, Parkville 3052, VIC, Australia
| | - Harshini Weerasinghe
- Infection Program and the Department of Biochemistry and Molecular Biology, Biomedicine Discovery Institute, Monash University, Clayton 3800, VIC, Australia
- Centre to Impact AMR, Monash University, Clayton 3800, VIC, Australia
| | - Aysha Sezmis
- School of Biological Sciences, Monash University, Clayton 3800, VIC, Australia
| | - Michael J McDonald
- Centre to Impact AMR, Monash University, Clayton 3800, VIC, Australia
- School of Biological Sciences, Monash University, Clayton 3800, VIC, Australia
| | - Ana Traven
- Infection Program and the Department of Biochemistry and Molecular Biology, Biomedicine Discovery Institute, Monash University, Clayton 3800, VIC, Australia
- Centre to Impact AMR, Monash University, Clayton 3800, VIC, Australia
| | - Philip Thompson
- Monash Institute of Pharmaceutical Sciences, Monash University, Parkville 3052, VIC, Australia
| | - Claudia Simm
- Infection Program and the Department of Biochemistry and Molecular Biology, Biomedicine Discovery Institute, Monash University, Clayton 3800, VIC, Australia
- Centre to Impact AMR, Monash University, Clayton 3800, VIC, Australia
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6
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Weerasinghe H, Simm C, Djajawi TM, Tedja I, Lo TL, Simpson DS, Shasha D, Mizrahi N, Olivier FAB, Speir M, Lawlor KE, Ben-Ami R, Traven A. Candida auris uses metabolic strategies to escape and kill macrophages while avoiding robust activation of the NLRP3 inflammasome response. Cell Rep 2023; 42:112522. [PMID: 37204928 DOI: 10.1016/j.celrep.2023.112522] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2022] [Revised: 03/28/2023] [Accepted: 05/01/2023] [Indexed: 05/21/2023] Open
Abstract
Metabolic adaptations regulate the response of macrophages to infection. The contributions of metabolism to macrophage interactions with the emerging fungal pathogen Candida auris are poorly understood. Here, we show that C. auris-infected macrophages undergo immunometabolic reprogramming and increase glycolysis but fail to activate a strong interleukin (IL)-1β cytokine response or curb C. auris growth. Further analysis shows that C. auris relies on its own metabolic capacity to escape from macrophages and proliferate in vivo. Furthermore, C. auris kills macrophages by triggering host metabolic stress through glucose starvation. However, despite causing macrophage cell death, C. auris does not trigger robust activation of the NLRP3 inflammasome. Consequently, inflammasome-dependent responses remain low throughout infection. Collectively, our findings show that C. auris uses metabolic regulation to eliminate macrophages while remaining immunologically silent to ensure its own survival. Thus, our data suggest that host and pathogen metabolism could represent therapeutic targets for C. auris infections.
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Affiliation(s)
- Harshini Weerasinghe
- Infection Program and the Department of Biochemistry and Molecular Biology, Biomedicine Discovery Institute, Monash University, Clayton, VIC 3800, Australia; Centre to Impact AMR, Monash University, Clayton, VIC 3800, Australia
| | - Claudia Simm
- Infection Program and the Department of Biochemistry and Molecular Biology, Biomedicine Discovery Institute, Monash University, Clayton, VIC 3800, Australia; Centre to Impact AMR, Monash University, Clayton, VIC 3800, Australia
| | - Tirta Mario Djajawi
- Centre for Innate Immunity and Infectious Diseases, Hudson Institute of Medical Research, Clayton, VIC 3168, Australia; Department of Molecular and Translational Science, Monash University, Clayton, VIC 3168, Australia
| | - Irma Tedja
- Infection Program and the Department of Biochemistry and Molecular Biology, Biomedicine Discovery Institute, Monash University, Clayton, VIC 3800, Australia; Centre to Impact AMR, Monash University, Clayton, VIC 3800, Australia
| | - Tricia L Lo
- Infection Program and the Department of Biochemistry and Molecular Biology, Biomedicine Discovery Institute, Monash University, Clayton, VIC 3800, Australia; Centre to Impact AMR, Monash University, Clayton, VIC 3800, Australia
| | - Daniel S Simpson
- The Walter and Eliza Hall Institute of Medical Research, Parkville, VIC 3052, Australia; The Department of Medical Biology, University of Melbourne, Parkville, VIC 3010, Australia
| | - David Shasha
- Infectious Diseases Unit, Tel Aviv Sourasky Medical Centre, Tel Aviv, Israel; Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel
| | - Naama Mizrahi
- Infectious Diseases Unit, Tel Aviv Sourasky Medical Centre, Tel Aviv, Israel
| | - Françios A B Olivier
- Infection Program and the Department of Biochemistry and Molecular Biology, Biomedicine Discovery Institute, Monash University, Clayton, VIC 3800, Australia; Centre to Impact AMR, Monash University, Clayton, VIC 3800, Australia; The Walter and Eliza Hall Institute of Medical Research, Parkville, VIC 3052, Australia
| | - Mary Speir
- Centre for Innate Immunity and Infectious Diseases, Hudson Institute of Medical Research, Clayton, VIC 3168, Australia; Department of Molecular and Translational Science, Monash University, Clayton, VIC 3168, Australia
| | - Kate E Lawlor
- Centre for Innate Immunity and Infectious Diseases, Hudson Institute of Medical Research, Clayton, VIC 3168, Australia; Department of Molecular and Translational Science, Monash University, Clayton, VIC 3168, Australia
| | - Ronen Ben-Ami
- Infectious Diseases Unit, Tel Aviv Sourasky Medical Centre, Tel Aviv, Israel; Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel
| | - Ana Traven
- Infection Program and the Department of Biochemistry and Molecular Biology, Biomedicine Discovery Institute, Monash University, Clayton, VIC 3800, Australia; Centre to Impact AMR, Monash University, Clayton, VIC 3800, Australia.
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Yau KPS, Weerasinghe H, Olivier FAB, Lo TL, Powell DR, Koch B, Beilharz TH, Traven A. The proteasome regulator Rpn4 controls antifungal drug tolerance by coupling protein homeostasis with metabolic responses to drug stress. PLoS Pathog 2023; 19:e1011338. [PMID: 37075064 PMCID: PMC10150987 DOI: 10.1371/journal.ppat.1011338] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2023] [Revised: 05/01/2023] [Accepted: 03/31/2023] [Indexed: 04/20/2023] Open
Abstract
Fungal pathogens overcome antifungal drug therapy by classic resistance mechanisms, such as increased efflux or changes to the drug target. However, even when a fungal strain is susceptible, trailing or persistent microbial growth in the presence of an antifungal drug can contribute to therapeutic failure. This trailing growth is caused by adaptive physiological changes that enable the growth of a subpopulation of fungal cells in high drug concentrations, in what is described as drug tolerance. Mechanistically, antifungal drug tolerance is not well understood. Here we report that the transcriptional activator Rpn4 is important for drug tolerance in the human fungal pathogen Candida albicans. Deletion of RPN4 eliminates tolerance to the commonly used antifungal drug fluconazole. We defined the mechanism and show that Rpn4 controls fluconazole tolerance via two target pathways. First, Rpn4 activates proteasome gene expression, which enables sufficient proteasome capacity to overcome fluconazole-induced proteotoxicity and the accumulation of ubiquitinated proteins targeted for degradation. Consistently, inhibition of the proteasome with MG132 eliminates fluconazole tolerance and resistance, and phenocopies the rpn4Δ/Δ mutant for loss of tolerance. Second, Rpn4 is required for wild type expression of the genes required for the synthesis of the membrane lipid ergosterol. Our data indicates that this function of Rpn4 is required for mitigating the inhibition of ergosterol biosynthesis by fluconazole. Based on our findings, we propose that Rpn4 is a central hub for fluconazole tolerance in C. albicans by coupling the regulation of protein homeostasis (proteostasis) and lipid metabolism to overcome drug-induced proteotoxicity and membrane stress.
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Affiliation(s)
- Ka Pui Sharon Yau
- Infection Program, Department of Biochemistry & Molecular Biology, Biomedicine Discovery Institute, Monash University, Clayton, Victoria, Australia
- Centre to Impact AMR, Monash University, Clayton, Victoria, Australia
| | - Harshini Weerasinghe
- Infection Program, Department of Biochemistry & Molecular Biology, Biomedicine Discovery Institute, Monash University, Clayton, Victoria, Australia
- Centre to Impact AMR, Monash University, Clayton, Victoria, Australia
| | - Francios A B Olivier
- Infection Program, Department of Biochemistry & Molecular Biology, Biomedicine Discovery Institute, Monash University, Clayton, Victoria, Australia
- Centre to Impact AMR, Monash University, Clayton, Victoria, Australia
| | - Tricia L Lo
- Infection Program, Department of Biochemistry & Molecular Biology, Biomedicine Discovery Institute, Monash University, Clayton, Victoria, Australia
- Centre to Impact AMR, Monash University, Clayton, Victoria, Australia
| | - David R Powell
- Bioinformatics Platform, Monash University, Clayton, Victoria, Australia
| | - Barbara Koch
- Infection Program, Department of Biochemistry & Molecular Biology, Biomedicine Discovery Institute, Monash University, Clayton, Victoria, Australia
| | - Traude H Beilharz
- Development and Stem Cells Program, Department of Biochemistry & Molecular Biology, Biomedicine Discovery Institute, Monash University, Clayton, Victoria, Australia
| | - Ana Traven
- Infection Program, Department of Biochemistry & Molecular Biology, Biomedicine Discovery Institute, Monash University, Clayton, Victoria, Australia
- Centre to Impact AMR, Monash University, Clayton, Victoria, Australia
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8
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Olivier FAB, Hilsenstein V, Weerasinghe H, Weir A, Hughes S, Crawford S, Vince JE, Hickey MJ, Traven A. The escape of Candida albicans from macrophages is enabled by the fungal toxin candidalysin and two host cell death pathways. Cell Rep 2022; 40:111374. [PMID: 36130496 DOI: 10.1016/j.celrep.2022.111374] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2021] [Revised: 06/15/2022] [Accepted: 08/26/2022] [Indexed: 11/25/2022] Open
Abstract
The egress of Candida hyphae from macrophages facilitates immune evasion, but it also alerts macrophages to infection and triggers inflammation. To better define the mechanisms, here we develop an imaging assay to directly and dynamically quantify hyphal escape and correlate it to macrophage responses. The assay reveals that Candida escapes by using two pore-forming proteins to permeabilize macrophage membranes: the fungal toxin candidalysin and Nlrp3 inflammasome-activated Gasdermin D. Candidalysin plays a major role in escape, with Nlrp3 and Gasdermin D-dependent and -independent contributions. The inactivation of Nlrp3 does not reduce hyphal escape, and we identify ETosis via macrophage extracellular trap formation as an additional pathway facilitating hyphal escape. Suppressing hyphal escape does not reduce fungal loads, but it does reduce inflammatory activation. Our findings explain how Candida escapes from macrophages by using three strategies: permeabilizing macrophage membranes via candidalysin and engaging two host cell death pathways, Gasdermin D-mediated pyroptosis and ETosis.
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Affiliation(s)
- Françios A B Olivier
- Infection Program, Department of Biochemistry and Molecular Biology, Biomedicine Discovery Institute, Monash University, Clayton 3800 VIC, Australia; Centre to Impact AMR, Monash University, Clayton, VIC 3800, Australia
| | | | - Harshini Weerasinghe
- Infection Program, Department of Biochemistry and Molecular Biology, Biomedicine Discovery Institute, Monash University, Clayton 3800 VIC, Australia; Centre to Impact AMR, Monash University, Clayton, VIC 3800, Australia
| | - Ashley Weir
- The Walter and Eliza Hall Institute of Medical Research, University of Melbourne, Parkville, VIC 3052, Australia; The Department of Medical Biology, University of Melbourne, Parkville, VIC 3010, Australia
| | - Sebastian Hughes
- The Walter and Eliza Hall Institute of Medical Research, University of Melbourne, Parkville, VIC 3052, Australia; The Department of Medical Biology, University of Melbourne, Parkville, VIC 3010, Australia
| | - Simon Crawford
- Monash Ramaciotti Centre for Cryo-Electron Microscopy, Monash University, Clayton, VIC 3800, Australia
| | - James E Vince
- The Walter and Eliza Hall Institute of Medical Research, University of Melbourne, Parkville, VIC 3052, Australia; The Department of Medical Biology, University of Melbourne, Parkville, VIC 3010, Australia
| | - Michael J Hickey
- Monash Centre for Inflammatory Diseases, Monash University Department of Medicine, Monash Medical Centre, Clayton, VIC 3168, Australia
| | - Ana Traven
- Infection Program, Department of Biochemistry and Molecular Biology, Biomedicine Discovery Institute, Monash University, Clayton 3800 VIC, Australia; Centre to Impact AMR, Monash University, Clayton, VIC 3800, Australia.
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9
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Simm C, Weerasinghe H, Thomas DR, Harrison PF, Newton HJ, Beilharz TH, Traven A. Disruption of Iron Homeostasis and Mitochondrial Metabolism Are Promising Targets to Inhibit Candida auris. Microbiol Spectr 2022; 10:e0010022. [PMID: 35412372 PMCID: PMC9045333 DOI: 10.1128/spectrum.00100-22] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2022] [Accepted: 03/21/2022] [Indexed: 11/20/2022] Open
Abstract
Fungal infections are a global threat, but treatments are limited due to a paucity in antifungal drug targets and the emergence of drug-resistant fungi such as Candida auris. Metabolic adaptations enable microbial growth in nutrient-scarce host niches, and they further control immune responses to pathogens, thereby offering opportunities for therapeutic targeting. Because it is a relatively new pathogen, little is known about the metabolic requirements for C. auris growth and its adaptations to counter host defenses. Here, we establish that triggering metabolic dysfunction is a promising strategy against C. auris. Treatment with pyrvinium pamoate (PP) induced metabolic reprogramming and mitochondrial dysfunction evident in disrupted mitochondrial morphology and reduced tricarboxylic acid (TCA) cycle enzyme activity. PP also induced changes consistent with disrupted iron homeostasis. Nutrient supplementation experiments support the proposition that PP-induced metabolic dysfunction is driven by disrupted iron homeostasis, which compromises carbon and lipid metabolism and mitochondria. PP inhibited C. auris replication in macrophages, which is a relevant host niche for this yeast pathogen. We propose that PP causes a multipronged metabolic hit to C. auris: it restricts the micronutrient iron to potentiate nutritional immunity imposed by immune cells, and it further causes metabolic dysfunction that compromises the utilization of macronutrients, thereby curbing the metabolic plasticity needed for growth in host environments. Our study offers a new avenue for therapeutic development against drug-resistant C. auris, shows how complex metabolic dysfunction can be caused by a single compound triggering antifungal inhibition, and provides insights into the metabolic needs of C. auris in immune cell environments. IMPORTANCE Over the last decade, Candida auris has emerged as a human pathogen around the world causing life-threatening infections with wide-spread antifungal drug resistance, including pandrug resistance in some cases. In this study, we addressed the mechanism of action of the antiparasitic drug pyrvinium pamoate against C. auris and show how metabolism could be inhibited to curb C. auris proliferation. We show that pyrvinium pamoate triggers sweeping metabolic and mitochondrial changes and disrupts iron homeostasis. PP-induced metabolic dysfunction compromises the utilization of both micro- and macronutrients by C. auris and reduces its growth in vitro and in immune phagocytes. Our findings provide insights into the metabolic requirements for C. auris growth and define the mechanisms of action of pyrvinium pamoate against C. auris, demonstrating how this compound works by inhibiting the metabolic flexibility of the pathogen. As such, our study characterizes credible avenues for new antifungal approaches against C. auris.
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Affiliation(s)
- Claudia Simm
- Infection Program and the Department of Biochemistry and Molecular Biology, Biomedicine Discovery Institute, Monash University, Victoria, Australia
- Centre to Impact AMR, Monash University, Victoria, Australia
| | - Harshini Weerasinghe
- Infection Program and the Department of Biochemistry and Molecular Biology, Biomedicine Discovery Institute, Monash University, Victoria, Australia
- Centre to Impact AMR, Monash University, Victoria, Australia
| | - David R. Thomas
- Department of Microbiology and Immunology, University of Melbourne at the Peter Doherty Institute for Infection and Immunity, Melbourne, Australia
| | | | - Hayley J. Newton
- Department of Microbiology and Immunology, University of Melbourne at the Peter Doherty Institute for Infection and Immunity, Melbourne, Australia
| | - Traude H. Beilharz
- Development and Stem Cells Program and the Department of Biochemistry and Molecular Biology, Biomedicine Discovery Institute, Monash University, Victoria, Australia
| | - Ana Traven
- Infection Program and the Department of Biochemistry and Molecular Biology, Biomedicine Discovery Institute, Monash University, Victoria, Australia
- Centre to Impact AMR, Monash University, Victoria, Australia
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10
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Abstract
Neutropenia predisposes patients to life-threatening infection with Candida albicans, a commensal and opportunistic fungal pathogen. How phenotypic variation in C. albicans isolates dictates neutrophil responses is poorly understood. By using a panel of clinical C. albicans strains, here we report that the prototype strain SC5314 induces the most potent accumulation of reactive oxygen species (ROS) and neutrophil extracellular traps (NETs) by human neutrophils of all tested isolates. ROS and NET accumulation positively correlated with the degree of hyphal formation by the isolates, the hypha being the fungal morphotype that promotes pathogenesis. However, there was no correlation of ROS and NET accumulation with fungal killing by neutrophils. Fungal killing was also not correlated with phagocytosis levels or oxidative stress susceptibility of the isolates. The bloodstream isolate P94015 cannot make hyphae and was previously shown to be hyperfit in the murine gut commensalism model. Our results show that P94015 displays poor phagocytosis by neutrophils, the least ROS and NET accumulation of all tested isolates, and resistance to neutrophil-mediated killing. Our data suggest that reduced susceptibility to neutrophils is likely to be independent from a previously described genetic mutation in P94015 that promotes commensalism. Reduced clearance by neutrophils could benefit commensal fitness of C. albicans and could also have promoted the virulence of P94015 in the human patient in the absence of hyphal morphogenesis. Collectively, our study provides new insights into neutrophil interactions with C. albicans and suggests that studying diverse isolates informs knowledge of the relevant aspects of this key immune interaction.IMPORTANCE Neutrophils are the key immune cell type for host defenses against infections with Candida albicansC. albicans strains isolated from patients display large phenotypic diversity, but how this diversity impacts host-pathogen interactions with neutrophils is incompletely defined. Here, we show that important neutrophil responses, such as accumulation of reactive oxygen species and neutrophil extracellular traps, as well as the levels of phagocytosis and killing of the pathogen, differ when comparing diverse C. albicans isolates. A bloodstream patient isolate previously described as more suited to commensalism than pathogenesis in animal models is relatively "silent" to neutrophils and resistant to killing. Our findings illuminate the relationships between fungal morphogenesis, neutrophil responses, and C. albicans survival. Our findings suggest that host phenotypes of a commensally adapted strain could be driven by resistance to immune clearance and indicate that we should extend our studies beyond the "prototype" strain SC5314 for deeper understanding of Candida-neutrophil interactions.
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Affiliation(s)
- Madhu Shankar
- Infection and Immunity Program, Biomedicine Discovery Institute, Monash University, Clayton (Melbourne), Victoria, Australia
- Department of Biochemistry and Molecular Biology, Biomedicine Discovery Institute, Monash University, Clayton (Melbourne), Victoria, Australia
| | - Tricia L Lo
- Infection and Immunity Program, Biomedicine Discovery Institute, Monash University, Clayton (Melbourne), Victoria, Australia
- Department of Biochemistry and Molecular Biology, Biomedicine Discovery Institute, Monash University, Clayton (Melbourne), Victoria, Australia
| | - Ana Traven
- Infection and Immunity Program, Biomedicine Discovery Institute, Monash University, Clayton (Melbourne), Victoria, Australia
- Department of Biochemistry and Molecular Biology, Biomedicine Discovery Institute, Monash University, Clayton (Melbourne), Victoria, Australia
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11
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Weerasinghe H, Traven A. Immunometabolism in fungal infections: the need to eat to compete. Curr Opin Microbiol 2020; 58:32-40. [PMID: 32781324 DOI: 10.1016/j.mib.2020.07.001] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2020] [Revised: 07/06/2020] [Accepted: 07/08/2020] [Indexed: 01/04/2023]
Abstract
Immune cells, including macrophages and monocytes, remodel their metabolism and have specific nutritional needs when dealing with microbial pathogens. While we are just beginning to understand immunometabolism in fungal infections, emerging themes include recognition of fungal cell surface molecule driving metabolic remodelling to increase glycolysis, the critical role of glycolysis in the production of antifungal cytokines and fungicidal effector molecules, and the need for maintaining host glucose homeostasis to defeat fungal infections. A crosstalk between host and pathogen metabolic pathways determines the fate of immune cells and fungi when they interact. Thus, immunometabolic interactions offer potential for innovation in antifungal treatments in the future. For this to become a reality, we must decipher the mechanisms by which diverse fungal pathogens activate and manipulate immunometabolism.
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Affiliation(s)
- Harshini Weerasinghe
- Infection and Immunity Program and the Department of Biochemistry and Molecular Biology, Biomedicine Discovery Institute, Monash University, Clayton (Melbourne), 3800 Victoria, Australia
| | - Ana Traven
- Infection and Immunity Program and the Department of Biochemistry and Molecular Biology, Biomedicine Discovery Institute, Monash University, Clayton (Melbourne), 3800 Victoria, Australia.
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12
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Tucey TM, Verma J, Olivier FAB, Lo TL, Robertson AAB, Naderer T, Traven A. Metabolic competition between host and pathogen dictates inflammasome responses to fungal infection. PLoS Pathog 2020; 16:e1008695. [PMID: 32750090 PMCID: PMC7433900 DOI: 10.1371/journal.ppat.1008695] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2020] [Revised: 08/18/2020] [Accepted: 06/07/2020] [Indexed: 12/11/2022] Open
Abstract
The NLRP3 inflammasome has emerged as a central immune regulator that senses virulence factors expressed by microbial pathogens for triggering inflammation. Inflammation can be harmful and therefore this response must be tightly controlled. The mechanisms by which immune cells, such as macrophages, discriminate benign from pathogenic microbes to control the NLRP3 inflammasome remain poorly defined. Here we used live cell imaging coupled with a compendium of diverse clinical isolates to define how macrophages respond and activate NLRP3 when faced with the human yeast commensal and pathogen Candida albicans. We show that metabolic competition by C. albicans, rather than virulence traits such as hyphal formation, activates NLRP3 in macrophages. Inflammasome activation is triggered by glucose starvation in macrophages, which occurs when fungal load increases sufficiently to outcompete macrophages for glucose. Consistently, reducing Candida’s ability to compete for glucose and increasing glucose availability for macrophages tames inflammatory responses. We define the mechanistic requirements for glucose starvation-dependent inflammasome activation by Candida and show that it leads to inflammatory cytokine production, but it does not trigger pyroptotic macrophage death. Pyroptosis occurs only with some Candida isolates and only under specific experimental conditions, whereas inflammasome activation by glucose starvation is broadly relevant. In conclusion, macrophages use their metabolic status, specifically glucose metabolism, to sense fungal metabolic activity and activate NLRP3 when microbial load increases. Therefore, a major consequence of Candida-induced glucose starvation in macrophages is activation of inflammatory responses, with implications for understanding how metabolism modulates inflammation in fungal infections. Activation of the immune regulator NLRP3 inflammasome by microbial pathogens has been shown to play both protective and destructive roles in infection, underscoring the importance of tight control over NLRP3-driven inflammation to ensure host health. A key microbe recognised by NLRP3 is the human yeast commensal and pathogen Candida albicans, which is responsible for mucosal and invasive infections. We demonstrate that innate immune cells sense their metabolic status to trigger NLRP3 activation only when microbial numbers have reached dangerous levels. This regulation is a consequence of metabolic competition between C. albicans and macrophages for an essential nutrient–glucose. The NLRP3 inflammasome is activated when increased fungal load in the infection microenvironment drives down glucose levels, thereby causing glucose starvation in macrophages. Restoring glucose homeostasis in macrophages reduced NLRP3 activation and production of the proinflammatory cytokine IL-1β, suggesting that metabolism regulates NLRP3 inflammasome activity in fungal infections.
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Affiliation(s)
- Timothy M. Tucey
- Infection and Immunity Program and the Department of Biochemistry and Molecular Biology, Biomedicine Discovery Institute, Monash University, Clayton, Victoria, Australia
| | - Jiyoti Verma
- Infection and Immunity Program and the Department of Biochemistry and Molecular Biology, Biomedicine Discovery Institute, Monash University, Clayton, Victoria, Australia
| | - Françios A. B. Olivier
- Infection and Immunity Program and the Department of Biochemistry and Molecular Biology, Biomedicine Discovery Institute, Monash University, Clayton, Victoria, Australia
| | - Tricia L. Lo
- Infection and Immunity Program and the Department of Biochemistry and Molecular Biology, Biomedicine Discovery Institute, Monash University, Clayton, Victoria, Australia
| | - Avril A. B. Robertson
- School of Chemistry and Molecular Biosciences, University of Queensland, Brisbane, Australia
| | - Thomas Naderer
- Infection and Immunity Program and the Department of Biochemistry and Molecular Biology, Biomedicine Discovery Institute, Monash University, Clayton, Victoria, Australia
| | - Ana Traven
- Infection and Immunity Program and the Department of Biochemistry and Molecular Biology, Biomedicine Discovery Institute, Monash University, Clayton, Victoria, Australia
- * E-mail:
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13
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Chow SH, Deo P, Yeung ATY, Kostoulias XP, Jeon Y, Gao ML, Seidi A, Olivier FAB, Sridhar S, Nethercott C, Cameron D, Robertson AAB, Robert R, Mackay CR, Traven A, Jin ZB, Hale C, Dougan G, Peleg AY, Naderer T. Targeting NLRP3 and Staphylococcal pore-forming toxin receptors in human-induced pluripotent stem cell-derived macrophages. J Leukoc Biol 2020; 108:967-981. [PMID: 32531864 DOI: 10.1002/jlb.4ma0420-497r] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2020] [Revised: 04/28/2020] [Accepted: 05/19/2020] [Indexed: 12/26/2022] Open
Abstract
Staphylococcus aureus causes necrotizing pneumonia by secreting toxins such as leukocidins that target front-line immune cells. The mechanism by which leukocidins kill innate immune cells and trigger inflammation during S. aureus lung infection, however, remains unresolved. Here, we explored human-induced pluripotent stem cell-derived macrophages (hiPSC-dMs) to study the interaction of the leukocidins Panton-Valentine leukocidin (PVL) and LukAB with lung macrophages, which are the initial leukocidin targets during S. aureus lung invasion. hiPSC-dMs were susceptible to the leukocidins PVL and LukAB and both leukocidins triggered NLPR3 inflammasome activation resulting in IL-1β secretion. hiPSC-dM cell death after LukAB exposure, however, was only temporarily dependent of NLRP3, although NLRP3 triggered marked cell death after PVL treatment. CRISPR/Cas9-mediated deletion of the PVL receptor, C5aR1, protected hiPSC-dMs from PVL cytotoxicity, despite the expression of other leukocidin receptors, such as CD45. PVL-deficient S. aureus had reduced ability to induce lung IL-1β levels in human C5aR1 knock-in mice. Unexpectedly, inhibiting NLRP3 activity resulted in increased wild-type S. aureus lung burdens. Our findings suggest that NLRP3 induces macrophage death and IL-1β secretion after PVL exposure and controls S. aureus lung burdens.
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Affiliation(s)
- Seong H Chow
- Infection & Immunity Program, Biomedicine Discovery Institute and Department of Biochemistry & Molecular Biology, Monash University, Clayton, Victoria, Australia
| | - Pankaj Deo
- Infection & Immunity Program, Biomedicine Discovery Institute and Department of Biochemistry & Molecular Biology, Monash University, Clayton, Victoria, Australia
| | - Amy T Y Yeung
- The Wellcome Sanger Institute, Wellcome Genome Campus, Hinxton, Cambridge, UK
| | - Xenia P Kostoulias
- Infection & Immunity Program, Biomedicine Discovery Institute and Department of Microbiology, Monash University, Clayton, Victoria, Australia
| | - Yusun Jeon
- Infection & Immunity Program, Biomedicine Discovery Institute and Department of Biochemistry & Molecular Biology, Monash University, Clayton, Victoria, Australia
| | - Mei-Ling Gao
- Laboratory of Stem Cell & Retinal Regeneration, Institute of Stem Cell Research, Division of Ophthalmic Genetics, The Eye Hospital, Wenzhou Medical University, Wenzhou, China.,National Center for International Research in Regenerative Medicine and Neurogenetics, National Clinical Research Center for Ophthalmology, State Key Laboratory of Ophthalmology, Optometry and Visual Science, Wenzhou, China
| | - Azadeh Seidi
- Infection & Immunity Program, Biomedicine Discovery Institute and Department of Biochemistry & Molecular Biology, Monash University, Clayton, Victoria, Australia
| | - Françios Alwyn Benson Olivier
- Infection & Immunity Program, Biomedicine Discovery Institute and Department of Biochemistry & Molecular Biology, Monash University, Clayton, Victoria, Australia
| | - Sushmita Sridhar
- The Wellcome Sanger Institute, Wellcome Genome Campus, Hinxton, Cambridge, UK
| | - Cara Nethercott
- Infection & Immunity Program, Biomedicine Discovery Institute and Department of Microbiology, Monash University, Clayton, Victoria, Australia
| | - David Cameron
- Infection & Immunity Program, Biomedicine Discovery Institute and Department of Microbiology, Monash University, Clayton, Victoria, Australia
| | - Avril A B Robertson
- School of Chemistry and Molecular Biosciences, The University of Queensland, St Lucia, Queensland, Australia
| | - Remy Robert
- Infection & Immunity Program, Biomedicine Discovery Institute and Department of Biochemistry & Molecular Biology, Monash University, Clayton, Victoria, Australia
| | - Charles R Mackay
- Infection & Immunity Program, Biomedicine Discovery Institute and Department of Microbiology, Monash University, Clayton, Victoria, Australia
| | - Ana Traven
- Infection & Immunity Program, Biomedicine Discovery Institute and Department of Biochemistry & Molecular Biology, Monash University, Clayton, Victoria, Australia
| | - Zi-Bing Jin
- Laboratory of Stem Cell & Retinal Regeneration, Institute of Stem Cell Research, Division of Ophthalmic Genetics, The Eye Hospital, Wenzhou Medical University, Wenzhou, China.,National Center for International Research in Regenerative Medicine and Neurogenetics, National Clinical Research Center for Ophthalmology, State Key Laboratory of Ophthalmology, Optometry and Visual Science, Wenzhou, China
| | - Christine Hale
- The Wellcome Sanger Institute, Wellcome Genome Campus, Hinxton, Cambridge, UK
| | - Gordon Dougan
- The Wellcome Sanger Institute, Wellcome Genome Campus, Hinxton, Cambridge, UK.,Department of Medicine, Addenbrookes Hospital, Cambridge, UK
| | - Anton Y Peleg
- Infection & Immunity Program, Biomedicine Discovery Institute and Department of Microbiology, Monash University, Clayton, Victoria, Australia.,Department of Infectious Diseases, the Alfred Hospital and Central Clinical School, Monash University, Melbourne, Australia
| | - Thomas Naderer
- Infection & Immunity Program, Biomedicine Discovery Institute and Department of Biochemistry & Molecular Biology, Monash University, Clayton, Victoria, Australia
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14
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Wang Q, Verma J, Vidan N, Wang Y, Tucey TM, Lo TL, Harrison PF, See M, Swaminathan A, Kuchler K, Tscherner M, Song J, Powell DR, Sopta M, Beilharz TH, Traven A. The YEATS Domain Histone Crotonylation Readers Control Virulence-Related Biology of a Major Human Pathogen. Cell Rep 2020; 31:107528. [PMID: 32320659 DOI: 10.1016/j.celrep.2020.107528] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2019] [Revised: 01/31/2020] [Accepted: 03/27/2020] [Indexed: 12/13/2022] Open
Abstract
Identification of multiple histone acylations diversifies transcriptional control by metabolism, but their functions are incompletely defined. Here we report evidence of histone crotonylation in the human fungal pathogen Candida albicans. We define the enzymes that regulate crotonylation and show its dynamic control by environmental signals: carbon sources, the short-chain fatty acids butyrate and crotonate, and cell wall stress. Crotonate regulates stress-responsive transcription and rescues C. albicans from cell wall stress, indicating broad impact on cell biology. The YEATS domain crotonylation readers Taf14 and Yaf9 are required for C. albicans virulence, and Taf14 controls gene expression, stress resistance, and invasive growth via its chromatin reader function. Blocking the Taf14 C terminus with a tag reduced virulence, suggesting that inhibiting Taf14 interactions with chromatin regulators impairs function. Our findings shed light on the regulation of histone crotonylation and the functions of the YEATS proteins in eukaryotic pathogen biology and fungal infections.
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Affiliation(s)
- Qi Wang
- Infection and Immunity Program and the Department of Biochemistry and Molecular Biology, Biomedicine Discovery Institute, Monash University, Clayton 3800 VIC, Australia
| | - Jiyoti Verma
- Infection and Immunity Program and the Department of Biochemistry and Molecular Biology, Biomedicine Discovery Institute, Monash University, Clayton 3800 VIC, Australia
| | - Nikolina Vidan
- Infection and Immunity Program and the Department of Biochemistry and Molecular Biology, Biomedicine Discovery Institute, Monash University, Clayton 3800 VIC, Australia; Department of Molecular Biology, Rudjer Boskovic Institute, Bijenicka 54, 10000 Zagreb, Croatia
| | - Yanan Wang
- Infection and Immunity Program and the Department of Biochemistry and Molecular Biology, Biomedicine Discovery Institute, Monash University, Clayton 3800 VIC, Australia
| | - Timothy M Tucey
- Infection and Immunity Program and the Department of Biochemistry and Molecular Biology, Biomedicine Discovery Institute, Monash University, Clayton 3800 VIC, Australia
| | - Tricia L Lo
- Infection and Immunity Program and the Department of Biochemistry and Molecular Biology, Biomedicine Discovery Institute, Monash University, Clayton 3800 VIC, Australia
| | - Paul F Harrison
- Bioinformatics Platform, Monash University, Clayton 3800 VIC, Australia
| | - Michael See
- Bioinformatics Platform, Monash University, Clayton 3800 VIC, Australia
| | - Angavai Swaminathan
- Development and Stem Cells Program and the Department of Biochemistry and Molecular Biology, Biomedicine Discovery Institute, Monash University, Clayton 3800 VIC, Australia
| | - Karl Kuchler
- Medical University of Vienna, Center for Medical Biochemistry, Max Perutz Labs, Campus Vienna Biocenter, Dr. Bohr-Gasse 9/2, Vienna, Austria
| | - Michael Tscherner
- Medical University of Vienna, Center for Medical Biochemistry, Max Perutz Labs, Campus Vienna Biocenter, Dr. Bohr-Gasse 9/2, Vienna, Austria
| | - Jiangning Song
- Infection and Immunity Program and the Department of Biochemistry and Molecular Biology, Biomedicine Discovery Institute, Monash University, Clayton 3800 VIC, Australia
| | - David R Powell
- Bioinformatics Platform, Monash University, Clayton 3800 VIC, Australia
| | - Mary Sopta
- Department of Molecular Biology, Rudjer Boskovic Institute, Bijenicka 54, 10000 Zagreb, Croatia
| | - Traude H Beilharz
- Development and Stem Cells Program and the Department of Biochemistry and Molecular Biology, Biomedicine Discovery Institute, Monash University, Clayton 3800 VIC, Australia
| | - Ana Traven
- Infection and Immunity Program and the Department of Biochemistry and Molecular Biology, Biomedicine Discovery Institute, Monash University, Clayton 3800 VIC, Australia.
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15
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Koch B, Barugahare AA, Lo TL, Huang C, Schittenhelm RB, Powell DR, Beilharz TH, Traven A. A Metabolic Checkpoint for the Yeast-to-Hyphae Developmental Switch Regulated by Endogenous Nitric Oxide Signaling. Cell Rep 2019; 25:2244-2258.e7. [PMID: 30463019 DOI: 10.1016/j.celrep.2018.10.080] [Citation(s) in RCA: 26] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2018] [Revised: 07/31/2018] [Accepted: 10/22/2018] [Indexed: 12/13/2022] Open
Abstract
The yeast Candida albicans colonizes several sites in the human body and responds to metabolic signals in commensal and pathogenic states. The yeast-to-hyphae transition correlates with virulence, but how metabolic status is integrated with this transition is incompletely understood. We used the putative mitochondrial fission inhibitor mdivi-1 to probe the crosstalk between hyphal signaling and metabolism. Mdivi-1 repressed C. albicans hyphal morphogenesis, but the mechanism was independent of its presumed target, the mitochondrial fission GTPase Dnm1. Instead, mdivi-1 triggered extensive metabolic reprogramming, consistent with metabolic stress, and reduced endogenous nitric oxide (NO) levels. Limiting endogenous NO stabilized the transcriptional repressor Nrg1 and inhibited the yeast-to-hyphae transition. We establish a role for endogenous NO signaling in C. albicans hyphal morphogenesis and suggest that NO regulates a metabolic checkpoint for hyphal growth. Furthermore, identifying NO signaling as an mdivi-1 target could inform its therapeutic applications in human diseases.
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Affiliation(s)
- Barbara Koch
- Infection and Immunity Program and the Department of Biochemistry and Molecular Biology, Biomedicine Discovery Institute, Monash University, Clayton, VIC 3800, Australia
| | - Adele A Barugahare
- Bioinformatics Platform, Monash University, Clayton, VIC 3800, Australia
| | - Tricia L Lo
- Infection and Immunity Program and the Department of Biochemistry and Molecular Biology, Biomedicine Discovery Institute, Monash University, Clayton, VIC 3800, Australia
| | - Cheng Huang
- Biomedical Proteomics Facility and the Department of Biochemistry and Molecular Biology, Biomedicine Discovery Institute, Monash University, Clayton, VIC 3800, Australia
| | - Ralf B Schittenhelm
- Biomedical Proteomics Facility and the Department of Biochemistry and Molecular Biology, Biomedicine Discovery Institute, Monash University, Clayton, VIC 3800, Australia
| | - David R Powell
- Bioinformatics Platform, Monash University, Clayton, VIC 3800, Australia
| | - Traude H Beilharz
- Development and Stem Cells Program and the Department of Biochemistry and Molecular Biology, Biomedicine Discovery Institute, Monash University, Clayton, VIC 3800, Australia
| | - Ana Traven
- Infection and Immunity Program and the Department of Biochemistry and Molecular Biology, Biomedicine Discovery Institute, Monash University, Clayton, VIC 3800, Australia.
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16
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Kesarwani V, Kelly HG, Shankar M, Robinson KJ, Kent SJ, Traven A, Corrie SR. Characterization of Key Bio-Nano Interactions between Organosilica Nanoparticles and Candida albicans. ACS Appl Mater Interfaces 2019; 11:34676-34687. [PMID: 31483991 DOI: 10.1021/acsami.9b10853] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
Nanoparticle-cell interactions between silica nanomaterials and mammalian cells have been investigated extensively in the context of drug delivery, diagnostics, and imaging. While there are also opportunities for applications in infectious disease, the interactions of silica nanoparticles with pathogenic microbes are relatively underexplored. To bridge this knowledge gap, here, we investigate the effects of organosilica nanoparticles of different sizes, concentrations, and surface coatings on surface association and viability of the major human fungal pathogen Candida albicans. We show that uncoated and PEGylated organosilica nanoparticles associate with C. albicans in a size and concentration-dependent manner, but on their own, do not elicit antifungal activity. The particles are also shown to associate with human white blood cells, in a similar trend as observed with C. albicans, and remain noncytotoxic toward neutrophils. Smaller particles are shown to have low association with C. albicans in comparison to other sized particles and their association with blood cells was also observed to be minimal. We further demonstrate that by chemically immobilizing the clinically important echinocandin class antifungal drug, caspofungin, to PEGylated nanoparticles, the cell-material interaction changes from benign to antifungal, inhibiting C. albicans growth when provided in high local concentration on a surface. Our study provides the foundation for defining how organosilica particles could be tailored for clinical applications against C. albicans. Possible future developments include designing biomaterials that could detect, prevent, or treat bloodstream C. albicans infections, which at present have very high patient mortality.
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Affiliation(s)
- Vidhishri Kesarwani
- Department of Chemical Engineering and ARC Centre of Excellence in Convergent Bio-Nano Science and Technology , Monash University , Clayton , Victoria 3800 , Australia
- Infection and Immunity Program and the Department of Biochemistry and Molecular Biology, Biomedicine Discovery Institute , Monash University , Clayton , Victoria 3800 , Australia
| | - Hannah G Kelly
- Department of Microbiology and Immunology, Peter Doherty Institute for Infection and Immunity, and ARC Centre of Excellence in Convergent BioNano Science and Technology , The University of Melbourne , Melbourne , Victoria 3010 , Australia
| | - Madhu Shankar
- Infection and Immunity Program and the Department of Biochemistry and Molecular Biology, Biomedicine Discovery Institute , Monash University , Clayton , Victoria 3800 , Australia
| | - Kye J Robinson
- Department of Chemical Engineering and ARC Centre of Excellence in Convergent Bio-Nano Science and Technology , Monash University , Clayton , Victoria 3800 , Australia
| | - Stephen J Kent
- Department of Microbiology and Immunology, Peter Doherty Institute for Infection and Immunity, and ARC Centre of Excellence in Convergent BioNano Science and Technology , The University of Melbourne , Melbourne , Victoria 3010 , Australia
| | - Ana Traven
- Infection and Immunity Program and the Department of Biochemistry and Molecular Biology, Biomedicine Discovery Institute , Monash University , Clayton , Victoria 3800 , Australia
| | - Simon R Corrie
- Department of Chemical Engineering and ARC Centre of Excellence in Convergent Bio-Nano Science and Technology , Monash University , Clayton , Victoria 3800 , Australia
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17
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Traven A, Naderer T. Central metabolic interactions of immune cells and microbes: prospects for defeating infections. EMBO Rep 2019; 20:e47995. [PMID: 31267653 PMCID: PMC6607010 DOI: 10.15252/embr.201947995] [Citation(s) in RCA: 36] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2019] [Revised: 04/22/2019] [Accepted: 05/27/2019] [Indexed: 12/16/2022] Open
Abstract
Antimicrobial drug resistance is threatening to take us to the "pre-antibiotic era", where people are dying from preventable and treatable diseases and the risk of hospital-associated infections compromises the success of surgery and cancer treatments. Development of new antibiotics is slow, and alternative approaches to control infections have emerged based on insights into metabolic pathways in host-microbe interactions. Central carbon metabolism of immune cells is pivotal in mounting an effective response to invading pathogens, not only to meet energy requirements, but to directly activate antimicrobial responses. Microbes are not passive players here-they remodel their metabolism to survive and grow in host environments. Sometimes, microbes might even benefit from the metabolic reprogramming of immune cells, and pathogens such as Candida albicans, Salmonella Typhimurium and Staphylococcus aureus can compete with activated host cells for sugars that are needed for essential metabolic pathways linked to inflammatory processes. Here, we discuss how metabolic interactions between innate immune cells and microbes determine their survival during infection, and ways in which metabolism could be manipulated as a therapeutic strategy.
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Affiliation(s)
- Ana Traven
- Infection and Immunity Program and the Department of Biochemistry & Molecular BiologyBiomedicine Discovery InstituteMonash UniversityClaytonVic.Australia
| | - Thomas Naderer
- Infection and Immunity Program and the Department of Biochemistry & Molecular BiologyBiomedicine Discovery InstituteMonash UniversityClaytonVic.Australia
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18
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Abstract
Mitochondrial fission shows potential as a therapeutic target in non-infectious human diseases. The compound mdivi-1 was identified as a mitochondrial fission inhibitor that acts against the evolutionarily conserved mitochondrial fission GTPase Dnm1/Drp1, and shows promising data in pre-clinical models of human pathologies. Two recent studies, however, found no evidence that mdivi-1 acts as a mitochondrial fission inhibitor and proposed other mechanisms. In mammalian cells, Bordt et al. showed that mdivi-1 inhibits complex I in mitochondria (Dev Cell 40:583, 2017). In a second study, we have recently demonstrated that mdivi-1 does not trigger a mitochondrial morphology change in the human yeast pathogen Candida albicans, but impacts on endogenous nitric oxide (NO) levels and inhibits the key virulence property of hyphal formation (Koch et al., Cell Rep 25:2244, 2018). Here we discuss recent insights into mdivi-1’s action in pathogenic fungi and the potential and challenges for repurposing it as an anti-infective. We also outline recent findings on the roles of mitochondrial fission in human and plant fungal pathogens, with the goal of starting the conversation on whether the research field of fungal pathogenesis can benefit from efforts in other disease areas aimed at developing therapeutic inhibitors of mitochondrial division.
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Affiliation(s)
- Barbara Koch
- Infection and Immunity Program and the Department of Biochemistry and Molecular Biology, Monash University, Clayton, VIC, 3800, Australia.,Protein, Science and Engineering, Callaghan Innovation, Christchurch, 8140, New Zealand
| | - Ana Traven
- Infection and Immunity Program and the Department of Biochemistry and Molecular Biology, Monash University, Clayton, VIC, 3800, Australia.
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19
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Abstract
Proper structure and function of the fungal cell wall are controlled by metabolic processes, as well as an interplay between a range of cellular organelles. Somewhat surprisingly, mitochondrial function has been shown to be important for proper cell wall biogenesis and integrity. Mitochondria also play a role in the susceptibility of fungi to cell wall-targeting drugs. This is true in a range of fungal species, including important human fungal pathogens. The biochemical mechanisms that explain the roles of mitochondria in cell wall biology have remained elusive, but studies to date strongly support the idea that mitochondrial control over cellular lipid homeostasis is at the core of these processes. Excitingly, recent evidence suggests that the mitochondria-lipid linkages drive resistance to the echinocandin drug caspofungin, a clinically important therapeutic that targets cell wall biosynthesis. Here, we review the state of affairs in mitochondria-fungal cell wall research and propose models that could be tested in future studies. Elucidating the mechanisms that drive fungal cell wall integrity through mitochondrial functions holds promise for developing new strategies to combat fungal infections, including the possibility to potentiate the effects of antifungal drugs and curb drug resistance.
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Affiliation(s)
- Barbara Koch
- Infection and Immunity Program, Department of Biochemistry and Molecular Biology, Monash University, Clayton, 3800, VIC, Australia.,Protein, Science and Engineering, Callaghan Innovation, Christchurch, 8140, New Zealand
| | - Ana Traven
- Infection and Immunity Program, Department of Biochemistry and Molecular Biology, Monash University, Clayton, 3800, VIC, Australia.
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20
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Tucey TM, Verma J, Harrison PF, Snelgrove SL, Lo TL, Scherer AK, Barugahare AA, Powell DR, Wheeler RT, Hickey MJ, Beilharz TH, Naderer T, Traven A. Glucose Homeostasis Is Important for Immune Cell Viability during Candida Challenge and Host Survival of Systemic Fungal Infection. Cell Metab 2018; 27:988-1006.e7. [PMID: 29719235 PMCID: PMC6709535 DOI: 10.1016/j.cmet.2018.03.019] [Citation(s) in RCA: 130] [Impact Index Per Article: 21.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/11/2017] [Revised: 12/18/2017] [Accepted: 03/26/2018] [Indexed: 12/20/2022]
Abstract
To fight infections, macrophages undergo a metabolic shift whereby increased glycolysis fuels antimicrobial inflammation and killing of pathogens. Here we demonstrate that the pathogen Candida albicans turns this metabolic reprogramming into an Achilles' heel for macrophages. During Candida-macrophage interactions intertwined metabolic shifts occur, with concomitant upregulation of glycolysis in both host and pathogen setting up glucose competition. Candida thrives on multiple carbon sources, but infected macrophages are metabolically trapped in glycolysis and depend on glucose for viability: Candida exploits this limitation by depleting glucose, triggering rapid macrophage death. Using pharmacological or genetic means to modulate glucose metabolism of host and/or pathogen, we show that Candida infection perturbs host glucose homeostasis in the murine candidemia model and demonstrate that glucose supplementation improves host outcomes. Our results support the importance of maintaining glucose homeostasis for immune cell survival during Candida challenge and for host survival in systemic infection.
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Affiliation(s)
- Timothy M Tucey
- Infection and Immunity Program and the Department of Biochemistry and Molecular Biology, Biomedicine Discovery Institute, Monash University, Clayton 3800, VIC, Australia
| | - Jiyoti Verma
- Infection and Immunity Program and the Department of Biochemistry and Molecular Biology, Biomedicine Discovery Institute, Monash University, Clayton 3800, VIC, Australia
| | - Paul F Harrison
- Bioinformatics Platform, Monash University, Clayton 3800, VIC, Australia
| | - Sarah L Snelgrove
- Centre for Inflammatory Diseases, Monash University Department of Medicine, Monash Medical Centre, Clayton 3168, VIC, Australia
| | - Tricia L Lo
- Infection and Immunity Program and the Department of Biochemistry and Molecular Biology, Biomedicine Discovery Institute, Monash University, Clayton 3800, VIC, Australia
| | - Allison K Scherer
- Department of Molecular & Biomedical Sciences, University of Maine, Orono, ME, USA
| | - Adele A Barugahare
- Bioinformatics Platform, Monash University, Clayton 3800, VIC, Australia
| | - David R Powell
- Bioinformatics Platform, Monash University, Clayton 3800, VIC, Australia
| | - Robert T Wheeler
- Department of Molecular & Biomedical Sciences, University of Maine, Orono, ME, USA
| | - Michael J Hickey
- Centre for Inflammatory Diseases, Monash University Department of Medicine, Monash Medical Centre, Clayton 3168, VIC, Australia
| | - Traude H Beilharz
- Development and Stem Cells Program and the Department of Biochemistry and Molecular Biology, Biomedicine Discovery Institute, Monash University, Clayton 3800, VIC, Australia
| | - Thomas Naderer
- Infection and Immunity Program and the Department of Biochemistry and Molecular Biology, Biomedicine Discovery Institute, Monash University, Clayton 3800, VIC, Australia.
| | - Ana Traven
- Infection and Immunity Program and the Department of Biochemistry and Molecular Biology, Biomedicine Discovery Institute, Monash University, Clayton 3800, VIC, Australia.
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21
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Koch B, Tucey TM, Lo TL, Novakovic S, Boag P, Traven A. The Mitochondrial GTPase Gem1 Contributes to the Cell Wall Stress Response and Invasive Growth of Candida albicans. Front Microbiol 2017; 8:2555. [PMID: 29326680 PMCID: PMC5742345 DOI: 10.3389/fmicb.2017.02555] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2017] [Accepted: 12/08/2017] [Indexed: 01/27/2023] Open
Abstract
The interactions of mitochondria with the endoplasmic reticulum (ER) are crucial for maintaining proper mitochondrial morphology, function and dynamics. This enables cells to utilize their mitochondria optimally for energy production and anabolism, and it further provides for metabolic control over developmental decisions. In fungi, a key mechanism by which ER and mitochondria interact is via a membrane tether, the protein complex ERMES (ER-Mitochondria Encounter Structure). In the model yeast Saccharomyces cerevisiae, the mitochondrial GTPase Gem1 interacts with ERMES, and it has been proposed to regulate its activity. Here we report on the first characterization of Gem1 in a human fungal pathogen. We show that in Candida albicans Gem1 has a dominant role in ensuring proper mitochondrial morphology, and our data is consistent with Gem1 working with ERMES in this role. Mitochondrial respiration and steady state cellular phospholipid homeostasis are not impacted by inactivation of GEM1 in C. albicans. There are two major virulence-related consequences of disrupting mitochondrial morphology by GEM1 inactivation: C. albicans becomes hypersusceptible to cell wall stress, and is unable to grow invasively. In the gem1Δ/Δ mutant, it is specifically the invasive capacity of hyphae that is compromised, not the ability to transition from yeast to hyphal morphology, and this phenotype is shared with ERMES mutants. As a consequence of the hyphal invasion defect, the gem1Δ/Δ mutant is drastically hypovirulent in the worm infection model. Activation of the mitogen activated protein (MAP) kinase Cek1 is reduced in the gem1Δ/Δ mutant, and this function could explain both the susceptibility to cell wall stress and lack of invasive growth. This result establishes a new, respiration-independent mechanism of mitochondrial control over stress signaling and hyphal functions in C. albicans. We propose that ER-mitochondria interactions and the ER-Mitochondria Organizing Network (ERMIONE) play important roles in adaptive responses in fungi, in particular cell surface-related mechanisms that drive invasive growth and stress responsive behaviors that support fungal pathogenicity.
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Affiliation(s)
- Barbara Koch
- Infection and Immunity Program and the Department of Biochemistry and Molecular Biology, Biomedicine Discovery Institute, Monash University, Clayton, VIC, Australia
| | - Timothy M Tucey
- Infection and Immunity Program and the Department of Biochemistry and Molecular Biology, Biomedicine Discovery Institute, Monash University, Clayton, VIC, Australia
| | - Tricia L Lo
- Infection and Immunity Program and the Department of Biochemistry and Molecular Biology, Biomedicine Discovery Institute, Monash University, Clayton, VIC, Australia
| | - Stevan Novakovic
- Development and Stem Cells Program and the Department of Biochemistry and Molecular Biology, Biomedicine Discovery Institute, Monash University, Clayton, VIC, Australia
| | - Peter Boag
- Development and Stem Cells Program and the Department of Biochemistry and Molecular Biology, Biomedicine Discovery Institute, Monash University, Clayton, VIC, Australia
| | - Ana Traven
- Infection and Immunity Program and the Department of Biochemistry and Molecular Biology, Biomedicine Discovery Institute, Monash University, Clayton, VIC, Australia
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22
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Cools TL, Vriens K, Struyfs C, Verbandt S, Ramada MHS, Brand GD, Bloch C, Koch B, Traven A, Drijfhout JW, Demuyser L, Kucharíková S, Van Dijck P, Spasic D, Lammertyn J, Cammue BPA, Thevissen K. The Antifungal Plant Defensin HsAFP1 Is a Phosphatidic Acid-Interacting Peptide Inducing Membrane Permeabilization. Front Microbiol 2017; 8:2295. [PMID: 29209301 PMCID: PMC5702387 DOI: 10.3389/fmicb.2017.02295] [Citation(s) in RCA: 31] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2017] [Accepted: 11/07/2017] [Indexed: 11/13/2022] Open
Abstract
HsAFP1, a plant defensin isolated from coral bells (Heuchera sanguinea), is characterized by broad-spectrum antifungal activity. Previous studies indicated that HsAFP1 binds to specific fungal membrane components, which had hitherto not been identified, and induces mitochondrial dysfunction and cell membrane permeabilization. In this study, we show that HsAFP1 reversibly interacts with the membrane phospholipid phosphatidic acid (PA), which is a precursor for the biosynthesis of other phospholipids, and to a lesser extent with various phosphatidyl inositol phosphates (PtdInsP's). Moreover, via reverse ELISA assays we identified two basic amino acids in HsAFP1, namely histidine at position 32 and arginine at position 52, as well as the phosphate group in PA as important features enabling this interaction. Using a HsAFP1 variant, lacking both amino acids (HsAFP1[H32A][R52A]), we showed that, as compared to the native peptide, the ability of this variant to bind to PA and PtdInsP's is reduced (≥74%) and the antifungal activity of the variant is reduced (≥2-fold), highlighting the link between PA/PtdInsP binding and antifungal activity. Using fluorescently labelled HsAFP1 in confocal microscopy and flow cytometry assays, we showed that HsAFP1 accumulates at the cell surface of yeast cells with intact membranes, most notably at the buds and septa. The resulting HsAFP1-induced membrane permeabilization is likely to occur after HsAFP1's internalization. These data provide novel mechanistic insights in the mode of action of the HsAFP1 plant defensin.
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Affiliation(s)
- Tanne L Cools
- Centre of Microbial and Plant Genetics, KU Leuven, Leuven, Belgium
| | - Kim Vriens
- Centre of Microbial and Plant Genetics, KU Leuven, Leuven, Belgium
| | - Caroline Struyfs
- Centre of Microbial and Plant Genetics, KU Leuven, Leuven, Belgium.,Department of Plant Systems Biology, VIB, Ghent, Belgium
| | - Sara Verbandt
- Centre of Microbial and Plant Genetics, KU Leuven, Leuven, Belgium
| | - Marcelo H S Ramada
- Graduate Program in Genomic Sciences and Biotechnology, Catholic University of Brasilia, Brasilia, Brazil.,Mass Spectrometry Laboratory, Embrapa Genetic Resources and Biotechnology, Brasilia, Brazil
| | - Guilherme D Brand
- Chemistry Institute, Campus Darcy Ribeiro, University of Brasilia, Brasilia, Brazil
| | - Carlos Bloch
- Mass Spectrometry Laboratory, Embrapa Genetic Resources and Biotechnology, Brasilia, Brazil
| | - Barbara Koch
- Department of Biochemistry and Molecular Biology, Monash University, Clayton, VIC, Australia
| | - Ana Traven
- Department of Biochemistry and Molecular Biology, Monash University, Clayton, VIC, Australia
| | - Jan W Drijfhout
- Department of Immunohematology and Blood Transfusion, Leiden University Medical Center, Leiden, Netherlands
| | - Liesbeth Demuyser
- Laboratory of Molecular Cell Biology, KU Leuven, Leuven, Belgium.,VIB-KU Leuven Center for Microbiology, Leuven, Belgium
| | - Soňa Kucharíková
- Laboratory of Molecular Cell Biology, KU Leuven, Leuven, Belgium.,VIB-KU Leuven Center for Microbiology, Leuven, Belgium
| | - Patrick Van Dijck
- Laboratory of Molecular Cell Biology, KU Leuven, Leuven, Belgium.,VIB-KU Leuven Center for Microbiology, Leuven, Belgium
| | | | | | - Bruno P A Cammue
- Centre of Microbial and Plant Genetics, KU Leuven, Leuven, Belgium.,Department of Plant Systems Biology, VIB, Ghent, Belgium
| | - Karin Thevissen
- Centre of Microbial and Plant Genetics, KU Leuven, Leuven, Belgium
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Affiliation(s)
- Bryan R. Coad
- Future Industries Institute, University of South Australia, Mawson Lakes, South Australia, Australia
| | - Hans J. Griesser
- Future Industries Institute, University of South Australia, Mawson Lakes, South Australia, Australia
| | - Anton Y. Peleg
- Infection and Immunity Program and the Department of Microbiology, Biomedicine Discovery Institute, Monash University, Clayton, Victoria, Australia
- Department of Infectious Diseases, Central Clinical School, Alfred Hospital and Monash University, Melbourne, Victoria, Australia
| | - Ana Traven
- Infection and Immunity Program and the Department of Biochemistry and Molecular Biology, Biomedicine Discovery Institute, Monash University, Clayton, Victoria, Australia
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24
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Verma-Gaur J, Traven A. Post-transcriptional gene regulation in the biology and virulence of Candida albicans. Cell Microbiol 2016; 18:800-6. [PMID: 26999710 PMCID: PMC5074327 DOI: 10.1111/cmi.12593] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2016] [Revised: 02/28/2016] [Accepted: 03/16/2016] [Indexed: 11/27/2022]
Abstract
In the human fungal pathogen Candida albicans, remodelling of gene expression drives host adaptation and virulence. Recent studies revealed that in addition to transcription, post‐transcriptional mRNA control plays important roles in virulence‐related pathways. Hyphal morphogenesis, biofilm formation, stress responses, antifungal drug susceptibility and virulence in animal models require post‐transcriptional regulators. This includes RNA binding proteins that control mRNA localization, decay and translation, as well as the cytoplasmic mRNA decay pathway. Comprehensive understanding of how modulation of gene expression networks drives C. albicans virulence will necessitate integration of our knowledge on transcriptional and post‐transcriptional mRNA control.
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Affiliation(s)
- Jiyoti Verma-Gaur
- Infection and Immunity Program and the Department of Biochemistry and Molecular Biology, Biomedicine Discovery Institute, Monash University, Clayton, VIC, Australia
| | - Ana Traven
- Infection and Immunity Program and the Department of Biochemistry and Molecular Biology, Biomedicine Discovery Institute, Monash University, Clayton, VIC, Australia
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25
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Qu Y, Locock K, Verma-Gaur J, Hay ID, Meagher L, Traven A. Searching for new strategies against polymicrobial biofilm infections: guanylated polymethacrylates kill mixed fungal/bacterial biofilms. J Antimicrob Chemother 2015; 71:413-21. [PMID: 26490013 DOI: 10.1093/jac/dkv334] [Citation(s) in RCA: 48] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2015] [Accepted: 09/14/2015] [Indexed: 01/15/2023] Open
Abstract
OBJECTIVES Biofilm-related human infections have high mortality rates due to drug resistance. Cohabitation of diverse microbes in polymicrobial biofilms is common and these infections present additional challenges for treatment compared with monomicrobial biofilms. Here, we address this therapeutic gap by assessing the potential of a new class of antimicrobial agents, guanylated polymethacrylates, in the treatment of polymicrobial biofilms built by two prominent human pathogens, the fungus Candida albicans and the bacterium Staphylococcus aureus. METHODS We used imaging and quantitative methods to test the antibiofilm efficacy of guanylated polymethacrylates, a new class of drugs that structurally mimic antimicrobial peptides. We further compared guanylated polymethacrylates with first-line antistaphylococcal and anti-Candida agents used as combinatorial therapy against polymicrobial biofilms. RESULTS Guanylated polymethacrylates were highly effective as a sole agent, killing both C. albicans and S. aureus when applied to established polymicrobial biofilms. Furthermore, they outperformed multiple combinations of current antimicrobial drugs, with one of the tested compounds killing 99.98% of S. aureus and 82.2% of C. albicans at a concentration of 128 mg/L. The extracellular biofilm matrix provided protection, increasing the MIC of the polymethacrylates by 2-4-fold when added to planktonic assays. Using the C. albicans bgl2ΔΔ mutant, we implicate matrix polysaccharide β-1,3 glucan in the mechanism of protection. Data for two structurally distinct polymers suggest that this mechanism could be minimized through chemical optimization of the polymer structure. Finally, we demonstrate that a potential application for these polymers is in antimicrobial lock therapy. CONCLUSIONS Guanylated polymethacrylates are a promising lead for the development of an effective monotherapy against C. albicans/S. aureus polymicrobial biofilms.
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Affiliation(s)
- Yue Qu
- Department of Biochemistry and Molecular Biology, Faculty of Medicine, Nursing and Health Science, Monash University, Clayton, VIC 3800, Australia Department of Microbiology, Faculty of Medicine, Nursing and Health Science, Monash University, Clayton, VIC 3800, Australia Department of Infectious Diseases, The Alfred Hospital and Monash University, Melbourne, VIC 3000, Australia
| | | | - Jiyoti Verma-Gaur
- Department of Biochemistry and Molecular Biology, Faculty of Medicine, Nursing and Health Science, Monash University, Clayton, VIC 3800, Australia
| | - Iain D Hay
- Department of Microbiology, Faculty of Medicine, Nursing and Health Science, Monash University, Clayton, VIC 3800, Australia
| | - Laurence Meagher
- CSIRO Manufacturing Flagship, Clayton, VIC 3168, Australia Department of Materials Science and Monash Institute of Medical Engineering, Monash University, Clayton, VIC 3800, Australia
| | - Ana Traven
- Department of Biochemistry and Molecular Biology, Faculty of Medicine, Nursing and Health Science, Monash University, Clayton, VIC 3800, Australia
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26
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Verma-Gaur J, Qu Y, Harrison PF, Lo TL, Quenault T, Dagley MJ, Bellousoff M, Powell DR, Beilharz TH, Traven A. Integration of Posttranscriptional Gene Networks into Metabolic Adaptation and Biofilm Maturation in Candida albicans. PLoS Genet 2015; 11:e1005590. [PMID: 26474309 PMCID: PMC4608769 DOI: 10.1371/journal.pgen.1005590] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2015] [Accepted: 09/17/2015] [Indexed: 11/19/2022] Open
Abstract
The yeast Candida albicans is a human commensal and opportunistic pathogen. Although both commensalism and pathogenesis depend on metabolic adaptation, the regulatory pathways that mediate metabolic processes in C. albicans are incompletely defined. For example, metabolic change is a major feature that distinguishes community growth of C. albicans in biofilms compared to suspension cultures, but how metabolic adaptation is functionally interfaced with the structural and gene regulatory changes that drive biofilm maturation remains to be fully understood. We show here that the RNA binding protein Puf3 regulates a posttranscriptional mRNA network in C. albicans that impacts on mitochondrial biogenesis, and provide the first functional data suggesting evolutionary rewiring of posttranscriptional gene regulation between the model yeast Saccharomyces cerevisiae and C. albicans. A proportion of the Puf3 mRNA network is differentially expressed in biofilms, and by using a mutant in the mRNA deadenylase CCR4 (the enzyme recruited to mRNAs by Puf3 to control transcript stability) we show that posttranscriptional regulation is important for mitochondrial regulation in biofilms. Inactivation of CCR4 or dis-regulation of mitochondrial activity led to altered biofilm structure and over-production of extracellular matrix material. The extracellular matrix is critical for antifungal resistance and immune evasion, and yet of all biofilm maturation pathways extracellular matrix biogenesis is the least understood. We propose a model in which the hypoxic biofilm environment is sensed by regulators such as Ccr4 to orchestrate metabolic adaptation, as well as the regulation of extracellular matrix production by impacting on the expression of matrix-related cell wall genes. Therefore metabolic changes in biofilms might be intimately linked to a key biofilm maturation mechanism that ultimately results in untreatable fungal disease. Metabolism is a master regulator of cell biology, including gene regulation, developmental switches and cellular life-death decisions, with the mitochondrion playing a central role in eukaryotes. For the yeast Candida albicans mitochondrial functions have been implicated in host-pathogen interactions, but the regulatory mechanism that control mitochondrial biogenesis are poorly described. We identified the RNA binding protein Puf3 as a new mitochondrial regulator in C. albicans, and show that posttranscriptional regulation and mitochondrial function have important roles during community growth in biofilms. Perturbation of mitochondrial activity or inactivation of a key posttranscriptional regulator, CCR4, led to changes in biofilm maturation, shedding light on the interface between metabolic reprogramming and biofilm developmental pathways. We illuminate a new mechanism that regulates extracellular matrix production, an essential biofilm feature that mediates the notorious drug resistance and immune evasion properties of the biofilm growth mode.
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Affiliation(s)
- Jiyoti Verma-Gaur
- Infection and Immunity Program, Biomedicine Discovery Institute and the Department of Biochemistry and Molecular Biology, Monash University, Clayton, Victoria, Australia
| | - Yue Qu
- Infection and Immunity Program, Biomedicine Discovery Institute and the Department of Biochemistry and Molecular Biology, Monash University, Clayton, Victoria, Australia
- Infection and Immunity Program, Biomedicine Discovery Institute and the Department of Microbiology, Monash University, Clayton, Victoria, Australia
| | - Paul F. Harrison
- Monash Bioinformatics Platform, Monash University, Clayton, Victoria, Australia
| | - Tricia L. Lo
- Infection and Immunity Program, Biomedicine Discovery Institute and the Department of Biochemistry and Molecular Biology, Monash University, Clayton, Victoria, Australia
| | - Tara Quenault
- Infection and Immunity Program, Biomedicine Discovery Institute and the Department of Biochemistry and Molecular Biology, Monash University, Clayton, Victoria, Australia
| | - Michael J. Dagley
- Infection and Immunity Program, Biomedicine Discovery Institute and the Department of Biochemistry and Molecular Biology, Monash University, Clayton, Victoria, Australia
| | - Matthew Bellousoff
- Infection and Immunity Program, Biomedicine Discovery Institute and the Department of Microbiology, Monash University, Clayton, Victoria, Australia
| | - David R. Powell
- Monash Bioinformatics Platform, Monash University, Clayton, Victoria, Australia
| | - Traude H. Beilharz
- Development and Stem Cells Program, Biomedicine Discovery Institute and the Department of Biochemistry and Molecular Biology, Monash University, Clayton, Victoria, Australia
- * E-mail: (THB); (AT)
| | - Ana Traven
- Infection and Immunity Program, Biomedicine Discovery Institute and the Department of Biochemistry and Molecular Biology, Monash University, Clayton, Victoria, Australia
- * E-mail: (THB); (AT)
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27
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Harrison PF, Powell DR, Clancy JL, Preiss T, Boag PR, Traven A, Seemann T, Beilharz TH. PAT-seq: a method to study the integration of 3'-UTR dynamics with gene expression in the eukaryotic transcriptome. RNA 2015; 21:1502-10. [PMID: 26092945 PMCID: PMC4509939 DOI: 10.1261/rna.048355.114] [Citation(s) in RCA: 59] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/23/2014] [Accepted: 04/20/2015] [Indexed: 05/21/2023]
Abstract
A major objective of systems biology is to quantitatively integrate multiple parameters from genome-wide measurements. To integrate gene expression with dynamics in poly(A) tail length and adenylation site, we developed a targeted next-generation sequencing approach, Poly(A)-Test RNA-sequencing. PAT-seq returns (i) digital gene expression, (ii) polyadenylation site/s, and (iii) the polyadenylation-state within and between eukaryotic transcriptomes. PAT-seq differs from previous 3' focused RNA-seq methods in that it depends strictly on 3' adenylation within total RNA samples and that the full-native poly(A) tail is included in the sequencing libraries. Here, total RNA samples from budding yeast cells were analyzed to identify the intersect between adenylation state and gene expression in response to loss of the major cytoplasmic deadenylase Ccr4. Furthermore, concordant changes to gene expression and adenylation-state were demonstrated in the classic Crabtree-Warburg metabolic shift. Because all polyadenylated RNA is interrogated by the approach, alternative adenylation sites, noncoding RNA and RNA-decay intermediates were also identified. Most important, the PAT-seq approach uses standard sequencing procedures, supports significant multiplexing, and thus replication and rigorous statistical analyses can for the first time be brought to the measure of 3'-UTR dynamics genome wide.
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Affiliation(s)
- Paul F Harrison
- Victorian Bioinformatics Consortium, Monash University, Clayton 3800, Australia Life Sciences Computation Centre, Victorian Life Sciences Computation Initiative, Carlton 3053, Australia Monash Bioinformatics Platform, Monash University, Clayton 3800, Australia
| | - David R Powell
- Victorian Bioinformatics Consortium, Monash University, Clayton 3800, Australia Life Sciences Computation Centre, Victorian Life Sciences Computation Initiative, Carlton 3053, Australia Monash Bioinformatics Platform, Monash University, Clayton 3800, Australia
| | - Jennifer L Clancy
- EMBL-Australia Collaborating Laboratory, Genome Biology Department, The John Curtin School of Medical Research (JCSMR), The Australian National University, Acton (Canberra) 2601, Australian Capital Territory, Australia
| | - Thomas Preiss
- EMBL-Australia Collaborating Laboratory, Genome Biology Department, The John Curtin School of Medical Research (JCSMR), The Australian National University, Acton (Canberra) 2601, Australian Capital Territory, Australia Victor Chang Cardiac Research Institute, Darlinghurst (Sydney), New South Wales 2010, Australia
| | - Peter R Boag
- Department of Biochemistry and Molecular Biology, Monash University, Clayton 3800, Australia
| | - Ana Traven
- Department of Biochemistry and Molecular Biology, Monash University, Clayton 3800, Australia
| | - Torsten Seemann
- Victorian Bioinformatics Consortium, Monash University, Clayton 3800, Australia Life Sciences Computation Centre, Victorian Life Sciences Computation Initiative, Carlton 3053, Australia
| | - Traude H Beilharz
- Department of Biochemistry and Molecular Biology, Monash University, Clayton 3800, Australia
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28
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Calderone R, Li D, Traven A. System-level impact of mitochondria on fungal virulence: to metabolism and beyond. FEMS Yeast Res 2015; 15:fov027. [PMID: 26002841 PMCID: PMC4542695 DOI: 10.1093/femsyr/fov027] [Citation(s) in RCA: 56] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Revised: 03/26/2015] [Accepted: 05/14/2015] [Indexed: 12/23/2022] Open
Abstract
The mitochondrion plays wide-ranging roles in eukaryotic cell physiology. In pathogenic fungi, this central metabolic organelle mediates a range of functions related to disease, from fitness of the pathogen to developmental and morphogenetic transitions to antifungal drug susceptibility. In this review, we present the latest findings in this area. We focus on likely mechanisms of mitochondrial impact on fungal virulence pathways through metabolism and stress responses, but also potentially via control over signaling pathways. We highlight fungal mitochondrial proteins that lack human homologs, and which could be inhibited as a novel approach to antifungal drug strategy.
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Affiliation(s)
- Richard Calderone
- Department of Microbiology and Immunology, Georgetown University Medical Center, Washington, DC 20057, USA
| | - Dongmei Li
- Department of Microbiology and Immunology, Georgetown University Medical Center, Washington, DC 20057, USA
| | - Ana Traven
- Department of Biochemistry and Molecular Biology, Monash University Clayton, 3800 VIC, Australia
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29
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Coad BR, Lamont-Friedrich SJ, Gwynne L, Jasieniak M, Griesser SS, Traven A, Peleg AY, Griesser HJ. Surface coatings with covalently attached caspofungin are effective in eliminating fungal pathogens. J Mater Chem B 2015; 3:8469-8476. [DOI: 10.1039/c5tb00961h] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
In this work we have prepared surface coatings formulated with the antifungal drug caspofungin, an approved pharmaceutical lipopeptide compound of the echinocandin drug class.
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Affiliation(s)
- Bryan R. Coad
- Mawson Institute
- University of South Australia
- Australia
| | | | - Lauren Gwynne
- Mawson Institute
- University of South Australia
- Australia
- The University of Bath
- UK
| | | | | | - Ana Traven
- Department of Biochemistry and Molecular Biology
- Monash University
- Clayton
- Australia
| | - Anton Y. Peleg
- Department of Infectious Diseases
- The Alfred Hospital and Monash University
- Melbourne
- Australia
- Department of Microbiology
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30
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Tucey T, Naderer T, Traven A. Candida and macrophages: a deadly affair. Microbiol Aust 2015. [DOI: 10.1071/ma15019] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
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31
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Affiliation(s)
- Ana Traven
- Department of Biochemistry and Molecular Biology, Monash University, Clayton, Victoria, Australia
- * E-mail: (AT); (TN)
| | - Thomas Naderer
- Department of Biochemistry and Molecular Biology, Monash University, Clayton, Victoria, Australia
- * E-mail: (AT); (TN)
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32
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Bleackley MR, Hayes BM, Parisi K, Saiyed T, Traven A, Potter ID, van der Weerden NL, Anderson MA. Bovine pancreatic trypsin inhibitor is a new antifungal peptide that inhibits cellular magnesium uptake. Mol Microbiol 2014; 92:1188-97. [DOI: 10.1111/mmi.12621] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 04/14/2014] [Indexed: 02/05/2023]
Affiliation(s)
- Mark R. Bleackley
- La Trobe Institute for Molecular Science; Melbourne Vic. 3086 Australia
| | - Brigitte M. Hayes
- La Trobe Institute for Molecular Science; Melbourne Vic. 3086 Australia
| | - Kathy Parisi
- La Trobe Institute for Molecular Science; Melbourne Vic. 3086 Australia
| | - Tamana Saiyed
- La Trobe Institute for Molecular Science; Melbourne Vic. 3086 Australia
| | - Ana Traven
- Department of Biochemistry and Molecular Biology; Monash University; Clayton Vic. 3800 Australia
| | - Ian D. Potter
- La Trobe Institute for Molecular Science; Melbourne Vic. 3086 Australia
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Hayes BME, Anderson MA, Traven A, van der Weerden NL, Bleackley MR. Activation of stress signalling pathways enhances tolerance of fungi to chemical fungicides and antifungal proteins. Cell Mol Life Sci 2014; 71:2651-66. [DOI: 10.1007/s00018-014-1573-8] [Citation(s) in RCA: 53] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2013] [Revised: 12/17/2013] [Accepted: 01/20/2014] [Indexed: 10/25/2022]
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Cerqueira GM, Kostoulias X, Khoo C, Aibinu I, Qu Y, Traven A, Peleg AY. A global virulence regulator in Acinetobacter baumannii and its control of the phenylacetic acid catabolic pathway. J Infect Dis 2014; 210:46-55. [PMID: 24431277 DOI: 10.1093/infdis/jiu024] [Citation(s) in RCA: 96] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023] Open
Abstract
BACKGROUND Acinetobacter baumannii is one of the most notorious hospital-acquired pathogens, and novel treatment strategies are desperately required. Two-component regulatory systems represent potential therapeutic targets as they mediate microorganism adaptation to changing environments, often control virulence, and are specific to bacteria. Here we describe the first global virulence regulator in A. baumannii. METHODS AND RESULTS Using transcriptional profiling and functional assays of a deletion mutant in the A. baumannii sensor kinase gene, A1S_0574 (termed as gacS), we show that this sensor kinase regulates key virulence characteristics, including pili synthesis, biofilms, and motility, resulting in virulence attenuation in a mammalian septicemia model. Notably, we also identified that GacS regulates an operon novel to A. baumannii (paa operon), which is responsible for the metabolism of aromatic compounds. Deletion of paaE (A1S_1340) confirmed the role of this operon in A. baumannii virulence. Finally, we identified the cognate response regulator (A1S_0236) for GacS and confirmed their interaction. A1S_0236 was shown to regulate 75% of the GacS transcriptome and the same virulence phenotypes. Overexpression of A1S_0236 restored virulence in the gacS mutant. CONCLUSIONS Our study characterizes a global virulence regulator, which may provide an alternate therapeutic target, in one of the most troublesome hospital-acquired pathogens.
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Michl TD, Locock KES, Stevens NE, Hayball JD, Vasilev K, Postma A, Qu Y, Traven A, Haeussler M, Meagher L, Griesser HJ. RAFT-derived antimicrobial polymethacrylates: elucidating the impact of end-groups on activity and cytotoxicity. Polym Chem 2014. [DOI: 10.1039/c4py00652f] [Citation(s) in RCA: 61] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
We report the use of RAFT polymerization to obtain eight cationic methacrylate polymers bearing amine or guanidine pendant groups, while varying the R- and Z-RAFT end-groups.
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Affiliation(s)
- Thomas D. Michl
- Ian Wark Research Institute
- University of South Australia
- Mawson Lakes, Australia
| | | | - Natalie Emilia Stevens
- Sansom Institute
- School of Pharmacy and Medical Sciences
- University of South Australia
- City East, Australia
| | - John D. Hayball
- Sansom Institute
- School of Pharmacy and Medical Sciences
- University of South Australia
- City East, Australia
| | - Krasimir Vasilev
- Mawson Institute
- University of South Australia
- Mawson Lakes, Australia
| | - Almar Postma
- CSIRO Materials Science and Engineering
- Clayton, Australia
| | - Yue Qu
- Department of Biochemistry and Molecular Biology
- Monash University
- Clayton, Australia
| | - Ana Traven
- Department of Biochemistry and Molecular Biology
- Monash University
- Clayton, Australia
| | | | | | - Hans J. Griesser
- Mawson Institute
- University of South Australia
- Mawson Lakes, Australia
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Panepinto JC, Heinz E, Traven A. The cellular roles of Ccr4-NOT in model and pathogenic fungi-implications for fungal virulence. Front Genet 2013; 4:302. [PMID: 24391665 PMCID: PMC3868889 DOI: 10.3389/fgene.2013.00302] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2013] [Accepted: 12/09/2013] [Indexed: 11/13/2022] Open
Abstract
The fungal Ccr4-NOT complex has been implicated in orchestrating gene expression networks that impact on pathways key for virulence in pathogenic species. The activity of Ccr4-NOT regulates cell wall integrity, antifungal drug susceptibility, adaptation to host temperature, and the developmental switches that enable the formation of pathogenic structures, such as filamentous hyphae. Moreover, Ccr4-NOT impacts on DNA repair pathways and genome stability, opening the possibility that this gene regulator could control adaptive responses in pathogens that are driven by chromosomal alterations. Here we provide a synthesis of the cellular roles of the fungal Ccr4-NOT, focusing on pathways important for virulence toward animals. Our review is based on studies in models yeasts Saccharomyces cerevisiae and Schizosaccharomyces pombe, and two species that cause serious human infections, Candida albicans and Cryptococcus neoformans. We hypothesize that the activity of Ccr4-NOT could be targeted for future antifungal drug discovery, a proposition supported by the fact that inactivation of the genes encoding subunits of Ccr4-NOT in C. albicans and C. neoformans reduces virulence in the mouse infection model. We performed bioinformatics analysis to identify similarities and differences between Ccr4-NOT subunits in fungi and animals, and discuss this knowledge in the context of future antifungal strategies.
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Affiliation(s)
- John C Panepinto
- Department of Microbiology and Immunology, University at Buffalo, The State University of New York Buffalo, NY, USA
| | - Eva Heinz
- Department of Microbiology, Monash University Clayton, VIC, Australia ; Victorian Bioinformatics Consortium, School of Biomedical Sciences, Monash University Clayton, VIC, Australia
| | - Ana Traven
- Department of Biochemistry and Molecular Biology, Monash University Clayton, VIC, Australia
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Locock KES, Michl TD, Valentin JDP, Vasilev K, Hayball JD, Qu Y, Traven A, Griesser HJ, Meagher L, Haeussler M. Guanylated Polymethacrylates: A Class of Potent Antimicrobial Polymers with Low Hemolytic Activity. Biomacromolecules 2013; 14:4021-31. [DOI: 10.1021/bm401128r] [Citation(s) in RCA: 157] [Impact Index Per Article: 14.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Affiliation(s)
- Katherine E. S. Locock
- CSIRO
Materials Science and Engineering, Bayview Avenue, Clayton, Victoria 3168, Australia
| | - Thomas D. Michl
- Ian
Wark Research Institute, University of South Australia, Mawson Lakes, South Australia 5095, Australia
| | - Jules D. P. Valentin
- Mawson
Institute, University of South Australia, Mawson Lakes, South Australia 5095, Australia
| | - Krasimir Vasilev
- Mawson
Institute, University of South Australia, Mawson Lakes, South Australia 5095, Australia
| | - John D. Hayball
- Sansom
Institute, School of Pharmacy and Medical Sciences, University of South Australia, City East, South Australia 5000, Australia
| | - Yue Qu
- Department
of Biochemistry and Molecular Biology, Monash University, Clayton, Victoria, Australia
| | - Ana Traven
- Department
of Biochemistry and Molecular Biology, Monash University, Clayton, Victoria, Australia
| | - Hans J. Griesser
- Ian
Wark Research Institute, University of South Australia, Mawson Lakes, South Australia 5095, Australia
| | - Laurence Meagher
- CSIRO
Materials Science and Engineering, Bayview Avenue, Clayton, Victoria 3168, Australia
| | - Matthias Haeussler
- CSIRO
Materials Science and Engineering, Bayview Avenue, Clayton, Victoria 3168, Australia
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Jeličić B, Nemet J, Traven A, Sopta M. Solvent-exposed serines in the Gal4 DNA-binding domain are required for promoter occupancy and transcriptional activation in vivo. FEMS Yeast Res 2013; 14:302-9. [PMID: 24119159 DOI: 10.1111/1567-1364.12106] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2013] [Revised: 08/27/2013] [Accepted: 09/27/2013] [Indexed: 11/30/2022] Open
Abstract
The yeast transcriptional activator Gal4 has long been the prototype for studies of eukaryotic transcription. Gal4 is phosphorylated in the DNA-binding domain (DBD); however, the molecular details and functional significance of this remain unknown. We mutagenized seven potential phosphoserines that lie on the solvent-exposed face of the DBD structure and assessed them for transcriptional activity and DNA binding in vivo. Serine to alanine mutants at positions 22, 47, and 85 show the greatest reduction in promoter occupancy and transcriptional activity at the MEL1 promoter containing a single UASGAL . Substitutions with the phosphomimetic aspartate restored DNA-binding and transcriptional activity at serines 22 and 85, suggesting that they are potential sites of Gal4 phosphorylation in vivo. In contrast, the serine to alanine mutants, except serine 22, were fully proficient for binding to the GAL1-10 promoter, containing multiple UASGAL sites, although they had a reduced ability to activate transcription. Collectively, these data show that at the GAL1-10 promoter, functions of the DBD in transcriptional activation can be uncoupled from roles in promoter binding. We suggest that the serines in the DBD mediate protein-protein contacts with the transcription machinery, leading to stabilization of Gal4 at promoters.
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Affiliation(s)
- Branka Jeličić
- Department of Molecular Biology, Ruđer Bošković Institute, Zagreb, Croatia
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Hewitt VL, Gabriel K, Traven A. The ins and outs of the intermembrane space: diverse mechanisms and evolutionary rewiring of mitochondrial protein import routes. Biochim Biophys Acta Gen Subj 2013; 1840:1246-53. [PMID: 23994494 DOI: 10.1016/j.bbagen.2013.08.013] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2013] [Revised: 08/09/2013] [Accepted: 08/20/2013] [Indexed: 11/24/2022]
Abstract
BACKGROUND Mitochondrial biogenesis is an essential process in all eukaryotes. Import of proteins from the cytosol into mitochondria is a key step in organelle biogenesis. Recent evidence suggests that a given mitochondrial protein does not take the same import route in all organisms, suggesting that pathways of mitochondrial protein import can be rewired through evolution. Examples of this process so far involve proteins destined to the mitochondrial intermembrane space (IMS). SCOPE OF REVIEW Here we review the components, substrates and energy sources of the known mechanisms of protein import into the IMS. We discuss evolutionary rewiring of the IMS import routes, focusing on the example of the lactate utilisation enzyme cytochrome b2 (Cyb2) in the model yeast Saccharomyces cerevisiae and the human fungal pathogen Candida albicans. MAJOR CONCLUSIONS There are multiple import pathways used for protein entry into the IMS and they form a network capable of importing a diverse range of substrates. These pathways have been rewired, possibly in response to environmental pressures, such as those found in the niches in the human body inhabited by C. albicans. GENERAL SIGNIFICANCE We propose that evolutionary rewiring of mitochondrial import pathways can adjust the metabolic fitness of a given species to their environmental niche. This article is part of a Special Issue entitled Frontiers of Mitochondrial.
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Affiliation(s)
- Victoria L Hewitt
- Department of Biochemistry and Molecular Biology, Building 77, Faculty of Medicine, Nursing and Health Sciences, Monash University, Melbourne 3800, Australia.
| | - Kipros Gabriel
- Department of Biochemistry and Molecular Biology, Building 77, Faculty of Medicine, Nursing and Health Sciences, Monash University, Melbourne 3800, Australia.
| | - Ana Traven
- Department of Biochemistry and Molecular Biology, Building 77, Faculty of Medicine, Nursing and Health Sciences, Monash University, Melbourne 3800, Australia.
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Hayes BME, Bleackley MR, Wiltshire JL, Anderson MA, Traven A, van der Weerden NL. Identification and mechanism of action of the plant defensin NaD1 as a new member of the antifungal drug arsenal against Candida albicans. Antimicrob Agents Chemother 2013; 57:3667-75. [PMID: 23689717 PMCID: PMC3719733 DOI: 10.1128/aac.00365-13] [Citation(s) in RCA: 86] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2013] [Accepted: 05/15/2013] [Indexed: 02/07/2023] Open
Abstract
In recent decades, pathogenic fungi have become a serious threat to human health, leading to major efforts aimed at characterizing new agents for improved treatments. Promising in this context are antimicrobial peptides produced by animals and plants as part of innate immune systems. Here, we describe an antifungal defensin, NaD1, with activity against the major human pathogen Candida albicans, characterize the mechanism of killing, and identify protection strategies used by the fungus to survive defensin treatment. The mechanism involves interaction between NaD1 and the fungal cell surface followed by membrane permeabilization, entry into the cytoplasm, hyperproduction of reactive oxygen species, and killing induced by oxidative damage. By screening C. albicans mutant libraries, we identified that the high-osmolarity glycerol (HOG) pathway has a unique role in protection against NaD1, while several other stress-responsive pathways are dispensable. The involvement of the HOG pathway is consistent with induction of oxidative stress by NaD1. The HOG pathway has been reported to have a major role in protection of fungi against osmotic stress, but our data indicate that osmotic stress does not contribute significantly to the adverse effects of NaD1 on C. albicans. Our data, together with previous studies with human beta-defensins and salivary histatin 5, indicate that inhibition of the HOG pathway holds promise as a broad strategy for increasing the activity of antimicrobial peptides against C. albicans.
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Affiliation(s)
| | - Mark R. Bleackley
- La Trobe Institute for Molecular Science, Melbourne, Victoria, Australia
| | | | | | - Ana Traven
- Department of Biochemistry and Molecular Biology, Monash University, Clayton, Victoria, Australia
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43
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Sengupta MS, Low WY, Patterson JR, Kim HM, Traven A, Beilharz TH, Colaiácovo MP, Schisa JA, Boag PR. ifet-1 is a broad-scale translational repressor required for normal P granule formation in C. elegans. J Cell Sci 2012; 126:850-9. [PMID: 23264733 DOI: 10.1242/jcs.119834] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
Large cytoplasmic ribonucleoprotein germ granule complexes are a common feature in germ cells. In C. elegans these are called P granules and for much of the life-cycle they associate with nuclear pore complexes in germ cells. P granules are rich in proteins that function in diverse RNA pathways. Here we report that the C. elegans homolog of the eIF4E-transporter IFET-1 is required for oogenesis but not spermatogenesis. We show that IFET-1 is required for translational repression of several maternal mRNAs in the distal gonad and functions in conjunction with the broad-scale translational regulators CGH-1, CAR-1 and PATR-1 to regulate germ cell sex determination. Furthermore we have found that IFET-1 localizes to P granules throughout the gonad and in the germ cell lineage in the embryo. Interestingly, IFET-1 is required for the normal ultrastructure of P granules and for the localization of CGH-1 and CAR-1 to P granules. Our findings suggest that IFET-1 is a key translational regulator and is required for normal P granule formation.
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Affiliation(s)
- Madhu S Sengupta
- Department of Biochemistry and Molecular Biology, Monash University, Victoria 3800, Australia
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44
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Traven A, Jänicke A, Harrison P, Swaminathan A, Seemann T, Beilharz TH. Transcriptional profiling of a yeast colony provides new insight into the heterogeneity of multicellular fungal communities. PLoS One 2012; 7:e46243. [PMID: 23029448 PMCID: PMC3460911 DOI: 10.1371/journal.pone.0046243] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2012] [Accepted: 08/28/2012] [Indexed: 11/22/2022] Open
Abstract
Understanding multicellular fungal structures is important for designing better strategies against human fungal pathogens. For example, the ability to form multicellular biofilms is a key virulence property of the yeast Candida albicans. C. albicans biofilms form on indwelling medical devices and are drug resistant, causing serious infections in hospital settings. Multicellular fungal communities are heterogeneous, consisting of cells experiencing different environments. Heterogeneity is likely important for the phenotypic characteristics of communities, yet it is poorly understood. Here we used colonies of the yeast Saccharomyces cerevisiae as a model fungal multicellular structure. We fractionated the outside colony layers from the cells in the center by FACS, using a Cit1-GFP marker expressed exclusively on the outside. Transcriptomics analysis of the two subpopulations revealed that the outside colony layers are actively growing by fermentative metabolism, while the cells residing on the inside are in a resting state and experience changes to mitochondrial activity. Our data shows several parallels with C. albicans biofilms providing insight into the contributions of heterogeneity to biofilm phenotypes. Hallmarks of C. albicans biofilms – the expression of ribosome and translation functions and activation of glycolysis and ergosterol biosynthesis occur on the outside of colonies, while expression of genes associates with sulfur assimilation is observed in the colony center. Cell wall restructuring occurs in biofilms, and cell wall functions are enriched in both fractions: the outside cells display enrichment of cell wall biosynthesis enzymes and cell wall proteins, while the inside cells express cell wall degrading enzymes. Our study also suggests that noncoding transcription and posttranscriptional mRNA regulation play important roles during growth of yeast in colonies, setting the scene for investigating these pathways in the development of multicellular fungal communities.
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Affiliation(s)
- Ana Traven
- Department of Biochemistry & Molecular Biology, Monash University, Clayton, Victoria, Australia
- * E-mail: (THB); (AT)
| | - Amrei Jänicke
- Department of Biochemistry & Molecular Biology, Monash University, Clayton, Victoria, Australia
| | - Paul Harrison
- Victorian Bioinformatics Consortium, Monash University, Clayton, Victoria, Australia
| | - Angavai Swaminathan
- Department of Biochemistry & Molecular Biology, Monash University, Clayton, Victoria, Australia
| | - Torsten Seemann
- Victorian Bioinformatics Consortium, Monash University, Clayton, Victoria, Australia
| | - Traude H. Beilharz
- Department of Biochemistry & Molecular Biology, Monash University, Clayton, Victoria, Australia
- * E-mail: (THB); (AT)
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Jänicke A, Vancuylenberg J, Boag PR, Traven A, Beilharz TH. ePAT: a simple method to tag adenylated RNA to measure poly(A)-tail length and other 3' RACE applications. RNA 2012; 18:1289-95. [PMID: 22543866 PMCID: PMC3358650 DOI: 10.1261/rna.031898.111] [Citation(s) in RCA: 57] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/04/2023]
Abstract
The addition of a poly(A)-tail to the 3' termini of RNA molecules influences stability, nuclear export, and efficiency of translation. In the cytoplasm, dynamic changes in the length of the poly(A)-tail have long been recognized as reflective of the switch between translational silence and activation. Thus, measurement of the poly(A)-tail associated with any given mRNA at steady-state can serve as a surrogate readout of its translation-state. Here, we describe a simple new method to 3'-tag adenylated RNA in total RNA samples using the intrinsic property of Escherichia coli DNA polymerase I to extend an RNA primer using a DNA template. This tag can serve as an anchor for cDNA synthesis and subsequent gene-specific PCR to assess poly(A)-tail length. We call this method extension Poly(A) Test (ePAT). The ePAT approach is as efficient as traditional Ligation-Mediated Poly(A) Test (LM-PAT) assays, avoids problems of internal priming associated with oligo-dT-based methods, and allows for the accurate analysis of both the poly(A)-tail length and alternate 3' UTR usage in 3' RACE applications.
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Affiliation(s)
- Amrei Jänicke
- Department of Biochemistry and Molecular Biology, Monash University, Clayton, Victoria 3800, Australia
| | - John Vancuylenberg
- Department of Biochemistry and Molecular Biology, Monash University, Clayton, Victoria 3800, Australia
| | - Peter R. Boag
- Department of Biochemistry and Molecular Biology, Monash University, Clayton, Victoria 3800, Australia
| | - Ana Traven
- Department of Biochemistry and Molecular Biology, Monash University, Clayton, Victoria 3800, Australia
| | - Traude H. Beilharz
- Department of Biochemistry and Molecular Biology, Monash University, Clayton, Victoria 3800, Australia
- Corresponding author.E-mail .
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Uwamahoro N, Qu Y, Jelicic B, Lo TL, Beaurepaire C, Bantun F, Quenault T, Boag PR, Ramm G, Callaghan J, Beilharz TH, Nantel A, Peleg AY, Traven A. The functions of Mediator in Candida albicans support a role in shaping species-specific gene expression. PLoS Genet 2012; 8:e1002613. [PMID: 22496666 PMCID: PMC3320594 DOI: 10.1371/journal.pgen.1002613] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2011] [Accepted: 02/07/2012] [Indexed: 01/01/2023] Open
Abstract
The Mediator complex is an essential co-regulator of RNA polymerase II that is conserved throughout eukaryotes. Here we present the first study of Mediator in the pathogenic fungus Candida albicans. We focused on the Middle domain subunit Med31, the Head domain subunit Med20, and Srb9/Med13 from the Kinase domain. The C. albicans Mediator shares some roles with model yeasts Saccharomyces cerevisiae and Schizosaccharomyces pombe, such as functions in the response to certain stresses and the role of Med31 in the expression of genes regulated by the activator Ace2. The C. albicans Mediator also has additional roles in the transcription of genes associated with virulence, for example genes related to morphogenesis and gene families enriched in pathogens, such as the ALS adhesins. Consistently, Med31, Med20, and Srb9/Med13 contribute to key virulence attributes of C. albicans, filamentation, and biofilm formation; and ALS1 is a biologically relevant target of Med31 for development of biofilms. Furthermore, Med31 affects virulence of C. albicans in the worm infection model. We present evidence that the roles of Med31 and Srb9/Med13 in the expression of the genes encoding cell wall adhesins are different between S. cerevisiae and C. albicans: they are repressors of the FLO genes in S. cerevisiae and are activators of the ALS genes in C. albicans. This suggests that Mediator subunits regulate adhesion in a distinct manner between these two distantly related fungal species.
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Affiliation(s)
- Nathalie Uwamahoro
- Department of Biochemistry and Molecular Biology, Monash University, Clayton, Victoria, Australia
| | - Yue Qu
- Department of Biochemistry and Molecular Biology, Monash University, Clayton, Victoria, Australia
- Department of Microbiology, Monash University, Clayton, Victoria, Australia
| | - Branka Jelicic
- Department of Biochemistry and Molecular Biology, Monash University, Clayton, Victoria, Australia
| | - Tricia L. Lo
- Department of Biochemistry and Molecular Biology, Monash University, Clayton, Victoria, Australia
| | - Cecile Beaurepaire
- Biotechnology Research Institute, National Research Council of Canada, Montreal, Quebec, Canada
| | - Farkad Bantun
- Department of Microbiology, Monash University, Clayton, Victoria, Australia
| | - Tara Quenault
- Department of Biochemistry and Molecular Biology, Monash University, Clayton, Victoria, Australia
| | - Peter R. Boag
- Department of Biochemistry and Molecular Biology, Monash University, Clayton, Victoria, Australia
| | - Georg Ramm
- Monash Micro Imaging, Monash University, Clayton, Australia
| | - Judy Callaghan
- Monash Micro Imaging, Monash University, Clayton, Australia
| | - Traude H. Beilharz
- Department of Biochemistry and Molecular Biology, Monash University, Clayton, Victoria, Australia
| | - André Nantel
- Biotechnology Research Institute, National Research Council of Canada, Montreal, Quebec, Canada
- * E-mail: (AT); (AN)
| | - Anton Y. Peleg
- Department of Microbiology, Monash University, Clayton, Victoria, Australia
- Department of Infectious Diseases, The Alfred Hospital, Melbourne, Victoria, Australia
| | - Ana Traven
- Department of Biochemistry and Molecular Biology, Monash University, Clayton, Victoria, Australia
- * E-mail: (AT); (AN)
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Alcock F, Webb CT, Dolezal P, Hewitt V, Shingu-Vasquez M, Likić VA, Traven A, Lithgow T. A small Tim homohexamer in the relict mitochondrion of Cryptosporidium. Mol Biol Evol 2011; 29:113-22. [PMID: 21984067 DOI: 10.1093/molbev/msr165] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
The apicomplexan parasite Cryptosporidium parvum possesses a mitosome, a relict mitochondrion with a greatly reduced metabolic capability. This mitosome houses a mitochondrial-type protein import apparatus, but elements of the protein import pathway have been reduced, and even lost, through evolution. The small Tim protein family is a case in point. The genomes of C. parvum and related species of Cryptosporidium each encode just one small Tim protein, CpTimS. This observation challenged the tenet that small Tim proteins are always found in pairs as α3β3 hexamers. We show that the atypical CpTimS exists as a relatively unstable homohexamer, shedding light both on the early evolution of the small Tim protein family and on small Tim hexamer formation in contemporary eukaryotes.
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Affiliation(s)
- Felicity Alcock
- Department of Biochemistry & Molecular Biology, Monash University, Clayton, Australia
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Quenault T, Lithgow T, Traven A. PUF proteins: repression, activation and mRNA localization. Trends Cell Biol 2011; 21:104-12. [DOI: 10.1016/j.tcb.2010.09.013] [Citation(s) in RCA: 199] [Impact Index Per Article: 15.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2010] [Revised: 09/20/2010] [Accepted: 09/28/2010] [Indexed: 12/15/2022]
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49
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Boyd SE, Keith JM, Traven A, Beilharz T. Probing connectivity between transcriptional and post-transcriptional gene networks. Microbiol Aust 2011. [DOI: 10.1071/ma11166] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
Abstract
The foundation for much of our current understanding of eukaryotic cell biology stems from studies exploiting the combined power of this yeast?s genetic tractability and its simple growth requirements. Furthermore, access to an early complete genome in 1996 allowed yeast researchers to spearhead the move toward genome-wide studies that underpin our thinking about systems-level biology today. Indeed, the last decade has been so rich in these studies that it has become close to impossible for most biologists to interrogate the data in an unbiased fashion. The challenge for the next decade is to generate the informational tools to sort the multidimensional datasets for underlying networks.
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50
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Dagley MJ, Gentle IE, Beilharz TH, Pettolino FA, Djordjevic JT, Lo TL, Uwamahoro N, Rupasinghe T, Tull DL, McConville M, Beaurepaire C, Nantel A, Lithgow T, Mitchell AP, Traven A. Cell wall integrity is linked to mitochondria and phospholipid homeostasis in Candida albicans through the activity of the post-transcriptional regulator Ccr4-Pop2. Mol Microbiol 2010; 79:968-89. [PMID: 21299651 DOI: 10.1111/j.1365-2958.2010.07503.x] [Citation(s) in RCA: 101] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The cell wall is essential for viability of fungi and is an effective drug target in pathogens such as Candida albicans. The contribution of post-transcriptional gene regulators to cell wall integrity in C. albicans is unknown. We show that the C. albicans Ccr4-Pop2 mRNA deadenylase, a regulator of mRNA stability and translation, is required for cell wall integrity. The ccr4/pop2 mutants display reduced wall β-glucans and sensitivity to the echinocandin caspofungin. Moreover, the deadenylase mutants are compromised for filamentation and virulence. We demonstrate that defective cell walls in the ccr4/pop2 mutants are linked to dysfunctional mitochondria and phospholipid imbalance. To further understand mitochondrial function in cell wall integrity, we screened a Saccharomyces cerevisiae collection of mitochondrial mutants. We identify several mitochondrial proteins required for caspofungin tolerance and find a connection between mitochondrial phospholipid homeostasis and caspofungin sensitivity. We focus on the mitochondrial outer membrane SAM complex subunit Sam37, demonstrating that it is required for both trafficking of phospholipids between the ER and mitochondria and cell wall integrity. Moreover, in C. albicans also Sam37 is essential for caspofungin tolerance. Our study provides the basis for an integrative view of mitochondrial function in fungal cell wall biogenesis and resistance to echinocandin antifungal drugs.
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Affiliation(s)
- Michael J Dagley
- Department of Biochemistry and Molecular Biology, Monash University, Melbourne, Australia
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