1
|
Xie J, Rybak JM, Martin-Vicente A, Guruceaga X, Thorn HI, Nywening AV, Ge W, Parker JE, Kelly SL, Rogers PD, Fortwendel JR. The sterol C-24 methyltransferase encoding gene, erg6, is essential for viability of Aspergillus species. Nat Commun 2024; 15:4261. [PMID: 38769341 PMCID: PMC11106247 DOI: 10.1038/s41467-024-48767-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2023] [Accepted: 05/09/2024] [Indexed: 05/22/2024] Open
Abstract
Triazoles, the most widely used class of antifungal drugs, inhibit the biosynthesis of ergosterol, a crucial component of the fungal plasma membrane. Inhibition of a separate ergosterol biosynthetic step, catalyzed by the sterol C-24 methyltransferase Erg6, reduces the virulence of pathogenic yeasts, but its effects on filamentous fungal pathogens like Aspergillus fumigatus remain unexplored. Here, we show that the lipid droplet-associated enzyme Erg6 is essential for the viability of A. fumigatus and other Aspergillus species, including A. lentulus, A. terreus, and A. nidulans. Downregulation of erg6 causes loss of sterol-rich membrane domains required for apical extension of hyphae, as well as altered sterol profiles consistent with the Erg6 enzyme functioning upstream of the triazole drug target, Cyp51A/Cyp51B. Unexpectedly, erg6-repressed strains display wild-type susceptibility against the ergosterol-active triazole and polyene antifungals. Finally, we show that erg6 repression results in significant reduction in mortality in a murine model of invasive aspergillosis. Taken together with recent studies, our work supports Erg6 as a potentially pan-fungal drug target.
Collapse
Affiliation(s)
- Jinhong Xie
- Graduate Program in Pharmaceutical Sciences, College of Graduate Health Sciences, University of Tennessee Health Science Center, Memphis, TN, USA
- Department of Clinical Pharmacy and Translational Science, College of Pharmacy, University of Tennessee Health Science Center, Memphis, TN, USA
| | - Jeffrey M Rybak
- Department of Pharmacy and Pharmaceutical Sciences, St. Jude Children's Research Hospital, Memphis, TN, USA
| | - Adela Martin-Vicente
- Department of Clinical Pharmacy and Translational Science, College of Pharmacy, University of Tennessee Health Science Center, Memphis, TN, USA
| | - Xabier Guruceaga
- Department of Clinical Pharmacy and Translational Science, College of Pharmacy, University of Tennessee Health Science Center, Memphis, TN, USA
| | - Harrison I Thorn
- Graduate Program in Pharmaceutical Sciences, College of Graduate Health Sciences, University of Tennessee Health Science Center, Memphis, TN, USA
- Department of Clinical Pharmacy and Translational Science, College of Pharmacy, University of Tennessee Health Science Center, Memphis, TN, USA
| | - Ashley V Nywening
- Department of Clinical Pharmacy and Translational Science, College of Pharmacy, University of Tennessee Health Science Center, Memphis, TN, USA
- Integrated Program in Biomedical Sciences, College of Graduate Health Sciences, University of Tennessee Health Science Center, Memphis, TN, USA
- Department of Microbiology, Immunology, and Biochemistry, College of Medicine, University of Tennessee Health Science Center, Memphis, TN, USA
| | - Wenbo Ge
- Department of Pharmacy and Pharmaceutical Sciences, St. Jude Children's Research Hospital, Memphis, TN, USA
| | - Josie E Parker
- Molecular Biosciences Division, School of Biosciences, Cardiff University, Cardiff, Wales, UK
| | - Steven L Kelly
- Institute of Life Science, Swansea University Medical School, Swansea, Wales, UK
| | - P David Rogers
- Department of Pharmacy and Pharmaceutical Sciences, St. Jude Children's Research Hospital, Memphis, TN, USA
| | - Jarrod R Fortwendel
- Department of Clinical Pharmacy and Translational Science, College of Pharmacy, University of Tennessee Health Science Center, Memphis, TN, USA.
- Department of Microbiology, Immunology, and Biochemistry, College of Medicine, University of Tennessee Health Science Center, Memphis, TN, USA.
| |
Collapse
|
2
|
Sumlu E, Aydin M, Korucu EN, Alyar S, Nsangou AM. Artemisinin May Disrupt Hyphae Formation by Suppressing Biofilm-Related Genes of Candida albicans: In Vitro and In Silico Approaches. Antibiotics (Basel) 2024; 13:310. [PMID: 38666986 PMCID: PMC11047306 DOI: 10.3390/antibiotics13040310] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2024] [Revised: 03/26/2024] [Accepted: 03/27/2024] [Indexed: 04/29/2024] Open
Abstract
This study aimed to assess the antifungal and antibiofilm efficacy of artemisinin against Candida (C.) species, analyze its impact on gene expression levels within C. albicans biofilms, and investigate the molecular interactions through molecular docking. The antifungal efficacy of artemisinin on a variety of Candida species, including fluconazole-resistant and -susceptible species, was evaluated by the microdilution method. The effect of artemisinin on C. albicans biofilm formation was investigated by MTT and FESEM. The mRNA expression of the genes related to biofilm was analyzed by qRT-PCR. In addition, molecular docking analysis was used to understand the interaction between artemisinin and C. albicans at the molecular level with RAS1-cAMP-EFG1 and EFG1-regulated genes. Artemisinin showed higher sensitivity against non-albicans Candida strains. Furthermore, artemisinin was strongly inhibitory against C. albicans biofilms at 640 µg/mL. Artemisinin downregulated adhesion-related genes ALS3, HWP1, and ECE1, hyphal development genes UME6 and HGC1, and hyphal CAMP-dependent protein kinase regulators CYR1, RAS1, and EFG1. Furthermore, molecular docking analysis revealed that artemisinin and EFG1 had the highest affinity, followed by UME6. FESEM analysis showed that the fluconazole- and artemisinin-treated groups exhibited a reduced hyphal network, unusual surface bulges, and the formation of pores on the cell surfaces. Our study suggests that artemisinin may have antifungal potential and showed a remarkable antibiofilm activity by significantly suppressing adhesion and hyphal development through interaction with key proteins involved in biofilm formation, such as EFG1.
Collapse
Affiliation(s)
- Esra Sumlu
- Department of Medical Pharmacology, Faculty of Medicine, KTO Karatay University, 42020 Konya, Turkey;
| | - Merve Aydin
- Department of Medical Microbiology, Faculty of Medicine, KTO Karatay University, 42020 Konya, Turkey
| | - Emine Nedime Korucu
- Department of Molecular Biology and Genetics, Faculty of Science, Necmettin Erbakan University, 42090 Konya, Turkey;
| | - Saliha Alyar
- Department of Chemistry, Faculty of Science, Karatekin University, 18100 Çankırı, Turkey;
| | - Ahmed Moustapha Nsangou
- Department of Medical Microbiology, Faculty of Medicine, Selçuk University, 42130 Konya, Turkey;
| |
Collapse
|
3
|
Chen Y, Gao F, Chen X, Tao S, Chen P, Lin W. The basic leucine zipper transcription factor MeaB is critical for biofilm formation, cell wall integrity, and virulence in Aspergillus fumigatus. mSphere 2024; 9:e0061923. [PMID: 38284755 PMCID: PMC10900910 DOI: 10.1128/msphere.00619-23] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2023] [Accepted: 12/18/2023] [Indexed: 01/30/2024] Open
Abstract
The regulation of fungal cell wall biosynthesis is crucial for cell wall integrity maintenance and directly impacts fungal pathogen virulence. Although numerous genes are involved in fungal cell wall polysaccharide biosynthesis through multiple pathways, the underlying regulatory mechanism is still not fully understood. In this study, we identified and functionally characterized a direct downstream target of SomA, the basic-region leucine zipper transcription factor MeaB, playing a certain role in Aspergillus fumigatus cell wall integrity. Loss of meaB reduces hyphal growth, causes severe defects in galactosaminogalactan-mediated biofilm formation, and attenuates virulence in a Galleria mellonella infection model. Furthermore, the meaB null mutant strain exhibited hypersensitivity to cell wall-perturbing agents and significantly alters the cell wall structure. Transcriptional profile analysis revealed that MeaB positively regulates the expression of the galactosaminogalactan biosynthesis and β-1,3-glucanosyltransferase genes uge3, agd3, and sph3 and gel1, gel5, and gel7, respectively, as well as genes involved in amino sugar and nucleotide sugar metabolism. Further study demonstrated that MeaB could respond to cell wall stress and contribute to the proper expression of mitogen-activated protein kinase genes mpkA and mpkC in the presence of different concentrations of congo red. In conclusion, A. fumigatus MeaB plays a critical role in cell wall integrity by governing the expression of genes encoding cell wall-related proteins, thus impacting the virulence of this fungus.IMPORTANCEAspergillus fumigatus is a common opportunistic mold that causes life-threatening infections in immunosuppressed patients. The fungal cell wall is a complex and dynamic organelle essential for the development of pathogenic fungi. Genes involved in cell wall polysaccharide biosynthesis and remodeling are crucial for fungal pathogen virulence. However, the potential regulatory mechanism for cell wall integrity remains to be fully defined in A. fumigatus. In the present study, we identify basic-region leucine zipper transcription factor MeaB as an important regulator of cell wall galactosaminogalactan biosynthesis and β-1,3-glucan remodeling that consequently impacts stress response and virulence of fungal pathogens. Thus, we illuminate a mechanism of transcriptional control fungal cell wall polysaccharide biosynthesis and stress response. As these cell wall components are promising therapeutic targets for fungal infections, understanding the regulatory mechanism of such polysaccharides will provide new therapeutic opportunities.
Collapse
Affiliation(s)
- Yuan Chen
- Nanjing University of Chinese Medicine, Nanjing Drum Tower Hospital, Nanjing, China
| | - Fei Gao
- Nanjing University of Chinese Medicine, Nanjing Drum Tower Hospital, Nanjing, China
| | - Xiaojin Chen
- Nanjing University of Chinese Medicine, Nanjing Drum Tower Hospital, Nanjing, China
| | - Siyuan Tao
- Nanjing University of Chinese Medicine, Nanjing Drum Tower Hospital, Nanjing, China
| | - Peiying Chen
- Nanjing University of Chinese Medicine, Nanjing Drum Tower Hospital, Nanjing, China
| | - Wei Lin
- Nanjing University of Chinese Medicine, Nanjing Drum Tower Hospital, Nanjing, China
- Jiangsu Collaborative Innovation Center of Chinese Medicinal Resources Industrialization, Nanjing, China
- State Key Laboratory of Bioreactor Engineering, East China University of Science and Technology, Shanghai, China
| |
Collapse
|
4
|
Wei S, Zhang Y, Wu M, Lv Y, Zhang S, Zhai H, Hu Y. Mechanisms of methyl 2-methylbutyrate suppression on Aspergillus flavus growth and aflatoxin B1 biosynthesis. Int J Food Microbiol 2024; 409:110462. [PMID: 37918192 DOI: 10.1016/j.ijfoodmicro.2023.110462] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2023] [Revised: 10/17/2023] [Accepted: 10/26/2023] [Indexed: 11/04/2023]
Abstract
Aspergillus flavus and subsequently produced carcinogenic aflatoxins frequently contaminate postharvest food crops, resulting in a threat to global food safety. Chemical preservatives are currently the main antifungal agents. However, fungal resistance effect, biological toxicity, and environmental contamination limit their practical applications. The application of natural volatile organic compounds has great potential for controlling fungal and mycotoxin contamination of postharvest food crops. This study therefore investigated the antifungal and anti-aflatoxigenic activities of the volatile compound, methyl 2-methylbutyrate (M2M), against Aspergillus flavus and its potential mechanisms. M2M effectively inhibited A. flavus mycelia growth, with a minimum inhibitory concentration of 2.0 μL/mL. Moreover, M2M also suppressed aflatoxin production, sclerotia production, and the pathogenicity on peanut and corn flour. RNA-Seq results showed that 2899 differentially expressed genes (DEGs), and DEGs involved in ergosterol synthesis, cell wall structure, glycolysis, citric acid cycle, mitogen activated protein kinase signaling pathway, DNA replication, and aflatoxin biosynthesis, were down-regulated in A. flavus. Further studies showed that M2M strongly damaged the cell membrane and cell wall integrity, reduced ATP levels, and induced reactive oxygen species (ROS) accumulation and DNA damage. Notably, a GATA type zinc finger transcription factor, AfSreA (AFLA_132440), which is essential for A. flavus growth and aflatoxin production, was identified. The growth and aflatoxin yield in the ΔAfSreA strain decreased by 94.94 % and 71.82 %, respectively. Additionally, deletion of AfSreA destroyed cell wall integrity and decreased expressions of genes involved in aflatoxin biosynthesis. Taken together, our results identified the antifungal and anti-aflatoxigenic mechanisms of M2M against A. flavus, and confirmed the potential of M2M in protecting peanut and corn from fungal contamination.
Collapse
Affiliation(s)
- Shan Wei
- College of Bioengineering, Henan University of Technology, Zhengzhou 450001, PR China
| | - Yige Zhang
- College of Bioengineering, Henan University of Technology, Zhengzhou 450001, PR China
| | - Menghan Wu
- College of Bioengineering, Henan University of Technology, Zhengzhou 450001, PR China
| | - Yangyong Lv
- College of Bioengineering, Henan University of Technology, Zhengzhou 450001, PR China
| | - Shuaibing Zhang
- College of Bioengineering, Henan University of Technology, Zhengzhou 450001, PR China
| | - Huanchen Zhai
- College of Bioengineering, Henan University of Technology, Zhengzhou 450001, PR China
| | - Yuansen Hu
- College of Bioengineering, Henan University of Technology, Zhengzhou 450001, PR China; Food Laboratory of Zhongyuan, Henan University of Technology, Luohe 462300, PR China.
| |
Collapse
|
5
|
Xie J, Rybak JM, Martin-Vicente A, Guruceaga X, Thorn HI, Nywening AV, Ge W, Parker JE, Kelly SL, Rogers PD, Fortwendel JR. The sterol C-24 methyltransferase encoding gene, erg6, is essential for viability of Aspergillus species. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.08.08.552489. [PMID: 37609350 PMCID: PMC10441335 DOI: 10.1101/2023.08.08.552489] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 08/24/2023]
Abstract
Ergosterol is a critical component of fungal plasma membranes. Although many currently available antifungal compounds target the ergosterol biosynthesis pathway for antifungal effect, current knowledge regarding ergosterol synthesis remains incomplete for filamentous fungal pathogens like Aspergillus fumigatus. Here, we show for the first time that the lipid droplet-associated sterol C-24 methyltransferase, Erg6, is essential for A. fumigatus viability. We further show that this essentiality extends to additional Aspergillus species, including A. lentulus, A. terreus, and A. nidulans. Neither the overexpression of a putative erg6 paralog, smt1, nor the exogenous addition of ergosterol could rescue erg6 deficiency. Importantly, Erg6 downregulation results in a dramatic decrease in ergosterol and accumulation in lanosterol and is further characterized by diminished sterol-rich plasma membrane domains (SRDs) at hyphal tips. Unexpectedly, erg6 repressed strains demonstrate wild-type susceptibility against the ergosterol-active triazole and polyene antifungals. Finally, repressing erg6 expression reduced fungal burden accumulation in a murine model of invasive aspergillosis. Taken together, our studies suggest that Erg6, which shows little homology to mammalian proteins, is potentially an attractive antifungal drug target for therapy of Aspergillus infections.
Collapse
Affiliation(s)
- Jinhong Xie
- Graduate Program in Pharmaceutical Sciences, College of Pharmacy, University of Tennessee Health Science Center, Memphis, TN, USA
- Department of Clinical Pharmacy and Translational Science, College of Pharmacy, University of Tennessee Health Science Center, Memphis, TN USA
| | - Jeffrey M. Rybak
- Department of Pharmacy and Pharmaceutical Sciences, St. Jude Children’s Research Hospital, Memphis, TN, USA
| | - Adela Martin-Vicente
- Department of Clinical Pharmacy and Translational Science, College of Pharmacy, University of Tennessee Health Science Center, Memphis, TN USA
| | - Xabier Guruceaga
- Department of Clinical Pharmacy and Translational Science, College of Pharmacy, University of Tennessee Health Science Center, Memphis, TN USA
| | - Harrison I. Thorn
- Graduate Program in Pharmaceutical Sciences, College of Pharmacy, University of Tennessee Health Science Center, Memphis, TN, USA
- Department of Clinical Pharmacy and Translational Science, College of Pharmacy, University of Tennessee Health Science Center, Memphis, TN USA
| | - Ashley V. Nywening
- Department of Clinical Pharmacy and Translational Science, College of Pharmacy, University of Tennessee Health Science Center, Memphis, TN USA
- Integrated Program in Biomedical Sciences, College of Graduate Health Sciences, University of Tennessee Health Science Center, Memphis, TN, USA
- Department of Microbiology, Immunology, and Biochemistry, College of Medicine, University of Tennessee Health Science Center, Memphis, TN, USA
| | - Wenbo Ge
- Department of Clinical Pharmacy and Translational Science, College of Pharmacy, University of Tennessee Health Science Center, Memphis, TN USA
| | - Josie E. Parker
- Molecular Biosciences Division, School of Biosciences, Cardiff University, Cardiff, Wales, UK
| | - Steven L. Kelly
- Institute of Life Science, Swansea University Medical School, Swansea, Wales, UK
| | - P. David Rogers
- Department of Pharmacy and Pharmaceutical Sciences, St. Jude Children’s Research Hospital, Memphis, TN, USA
| | - Jarrod R. Fortwendel
- Department of Clinical Pharmacy and Translational Science, College of Pharmacy, University of Tennessee Health Science Center, Memphis, TN USA
- Department of Microbiology, Immunology, and Biochemistry, College of Medicine, University of Tennessee Health Science Center, Memphis, TN, USA
| |
Collapse
|
6
|
Nicoletti G, White K. The Anti-Fungal Activity of Nitropropenyl Benzodioxole (NPBD), a Redox-Thiol Oxidant and Tyrosine Phosphatase Inhibitor. Antibiotics (Basel) 2022; 11:antibiotics11091188. [PMID: 36139967 PMCID: PMC9495065 DOI: 10.3390/antibiotics11091188] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2022] [Revised: 08/28/2022] [Accepted: 08/30/2022] [Indexed: 11/16/2022] Open
Abstract
Phylogenetically diverse fungal species are an increasing cause of severe disease and mortality. Identification of new targets and development of new fungicidal drugs are required to augment the effectiveness of current chemotherapy and counter increasing resistance in pathogens. Nitroalkenyl benzene derivatives are thiol oxidants and inhibitors of cysteine-based molecules, which show broad biological activity against microorganisms. Nitropropenyl benzodioxole (NPBD), one of the most active antimicrobial derivatives, shows high activity in MIC assays for phylogenetically diverse saprophytic, commensal and parasitic fungi. NPBD was fungicidal to all species except the dermatophytic fungi, with an activity profile comparable to that of Amphotericin B and Miconazole. NPBD showed differing patterns of dynamic kill rates under different growth conditions for Candida albicans and Aspergillus fumigatus and was rapidly fungicidal for non-replicating vegetative forms and microconidia. It did not induce resistant or drug tolerant strains in major pathogens on long term exposure. A literature review highlights the complexity and interactivity of fungal tyrosine phosphate and redox signaling pathways, their differing metabolic effects in fungal species and identifies some targets for inhibition. A comparison of the metabolic activities of Amphotericin B, Miconazole and NPBD highlights the multiple cellular functions of these agents and the complementarity of many mechanisms. The activity profile of NPBD illustrates the functional diversity of fungal tyrosine phosphatases and thiol-based redox active molecules and contributes to the validation of tyrosine phosphatases and redox thiol molecules as related and complementary selective targets for antimicrobial drug development. NPBD is a selective antifungal agent with low oral toxicity which would be suitable for local treatment of skin and mucosal infections.
Collapse
|
7
|
Verburg K, van Neer J, Duca M, de Cock H. Novel Treatment Approach for Aspergilloses by Targeting Germination. J Fungi (Basel) 2022; 8:758. [PMID: 35893126 PMCID: PMC9331470 DOI: 10.3390/jof8080758] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2022] [Revised: 07/03/2022] [Accepted: 07/19/2022] [Indexed: 12/24/2022] Open
Abstract
Germination of conidia is an essential process within the Aspergillus life cycle and plays a major role during the infection of hosts. Conidia are able to avoid detection by the majority of leukocytes when dormant. Germination can cause severe health problems, specifically in immunocompromised people. Aspergillosis is most often caused by Aspergillus fumigatus (A. fumigatus) and affects neutropenic patients, as well as people with cystic fibrosis (CF). These patients are often unable to effectively detect and clear the conidia or hyphae and can develop chronic non-invasive and/or invasive infections or allergic inflammatory responses. Current treatments with (tri)azoles can be very effective to combat a variety of fungal infections. However, resistance against current azoles has emerged and has been increasing since 1998. As a consequence, patients infected with resistant A. fumigatus have a reported mortality rate of 88% to 100%. Especially with the growing number of patients that harbor azole-resistant Aspergilli, novel antifungals could provide an alternative. Aspergilloses differ in defining characteristics, but germination of conidia is one of the few common denominators. By specifically targeting conidial germination with novel antifungals, early intervention might be possible. In this review, we propose several morphotypes to disrupt conidial germination, as well as potential targets. Hopefully, new antifungals against such targets could contribute to disturbing the ability of Aspergilli to germinate and grow, resulting in a decreased fungal burden on patients.
Collapse
Affiliation(s)
- Kim Verburg
- Molecular Microbiology, Department of Biology, Faculty of Science, Utrecht University, Padualaan 8, 3584 CH Utrecht, The Netherlands; (K.V.); (J.v.N.)
| | - Jacq van Neer
- Molecular Microbiology, Department of Biology, Faculty of Science, Utrecht University, Padualaan 8, 3584 CH Utrecht, The Netherlands; (K.V.); (J.v.N.)
| | - Margherita Duca
- Department of Chemical Biology & Drug Discovery, Utrecht Institute for Pharmaceutical Sciences, Utrecht University, 3584 CG Utrecht, The Netherlands;
| | - Hans de Cock
- Molecular Microbiology, Department of Biology, Faculty of Science, Utrecht University, Padualaan 8, 3584 CH Utrecht, The Netherlands; (K.V.); (J.v.N.)
| |
Collapse
|
8
|
Chen H, He S, Zhang S, A R, Li W, Liu S. The Necrotroph Botrytis cinerea BcSpd1 Plays a Key Role in Modulating Both Fungal Pathogenic Factors and Plant Disease Development. FRONTIERS IN PLANT SCIENCE 2022; 13:820767. [PMID: 35845699 PMCID: PMC9280406 DOI: 10.3389/fpls.2022.820767] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 11/23/2021] [Accepted: 06/01/2022] [Indexed: 06/15/2023]
Abstract
Botrytis cinerea is a necrotrophic microbe that causes gray mold disease in a broad range of hosts. In the present study, we conducted molecular microbiology and transcriptomic analyses of the host-B. cinerea interaction to investigate the plant defense response and fungal pathogenicity. Upon B. cinerea infection, plant defense responses changed from activation to repression; thus, the expression of many defense genes decreased in Arabidopsis thaliana. B. cinerea Zn(II)2Cys6 transcription factor BcSpd1 was involved in the suppression of plant defense as ΔBcSpd1 altered wild-type B05.10 virulence by recovering part of the defense responses at the early infection stage. BcSpd1 affected genes involved in the fungal sclerotium development, infection cushion formation, biosynthesis of melanin, and change in environmental pH values, which were reported to influence fungal virulence. Specifically, BcSpd1 bound to the promoter of the gene encoding quercetin dioxygenase (BcQdo) and positively affected the gene expression, which was involved in catalyzing antifungal flavonoid degradation. This study indicates BcSpd1 plays a key role in the necrotrophic microbe B. cinerea virulence toward plants by regulating pathogenicity-related compounds and thereby suppressing early plant defense.
Collapse
Affiliation(s)
| | | | | | | | | | - Shouan Liu
- Laboratory of Molecular Plant Pathology, Jilin University, Changchun, China
| |
Collapse
|
9
|
CRISPR-Cas9 approach confirms Calcineurin-responsive zinc finger 1 (Crz1) transcription factor as a promising therapeutic target in echinocandin-resistant Candida glabrata. PLoS One 2022; 17:e0265777. [PMID: 35303047 PMCID: PMC8932611 DOI: 10.1371/journal.pone.0265777] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2021] [Accepted: 03/07/2022] [Indexed: 11/19/2022] Open
Abstract
Invasive fungal infections, which kill more than 1.6 million patients each year worldwide, are difficult to treat due to the limited number of antifungal drugs (azoles, echinocandins, and polyenes) and the emergence of antifungal resistance. The transcription factor Crz1, a key regulator of cellular stress responses and virulence, is an attractive therapeutic target because this protein is absent in human cells. Here, we used a CRISPR-Cas9 approach to generate isogenic crz1Δ strains in two clinical isolates of caspofungin-resistant C. glabrata to analyze the role of this transcription factor in susceptibility to echinocandins, stress tolerance, biofilm formation, and pathogenicity in both non-vertebrate (Galleria mellonella) and vertebrate (mice) models of candidiasis. In these clinical isolates, CRZ1 disruption restores the susceptibility to echinocandins in both in vitro and in vivo models, and affects their oxidative stress response, biofilm formation, cell size, and pathogenicity. These results strongly suggest that Crz1 inhibitors may play an important role in the development of novel therapeutic agents against fungal infections considering the emergence of antifungal resistance and the low number of available antifungal drugs.
Collapse
|
10
|
Amich J. Sulfur Metabolism as a Promising Source of New Antifungal Targets. J Fungi (Basel) 2022; 8:295. [PMID: 35330297 PMCID: PMC8951744 DOI: 10.3390/jof8030295] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2022] [Revised: 02/23/2022] [Accepted: 03/11/2022] [Indexed: 12/31/2022] Open
Abstract
Fungal infections are a growing threat to human health. Despite their clinical relevance, there is a surprisingly limited availability of clinically approved antifungal agents, which is seriously aggravated by the recent appearance and fast spread of drug resistance. It is therefore clear that there is an urgent need for novel and efficient antifungals. In this context, metabolism is recognized as a promising source for new antifungal targets and, indeed, there are new drugs in development that target metabolic pathways. Fungal sulfur metabolism is particularly interesting, as many of its processes are essential for viability and/or pathogenicity and it shows substantial differences with human metabolism. This short-review will summarize our current knowledge of sulfur-related genes and routes that are important for Aspergillus fumigatus virulence, which consequently could be pursued for drug development.
Collapse
Affiliation(s)
- Jorge Amich
- Mycology Reference Laboratory, National Centre for Microbiology, Instituto de Salud Carlos III (ISCIII), Majadahonda, 28222 Madrid, Spain;
- Manchester Fungal Infection Group (MFIG), Division of Evolution, Infection, and Genomics, Faculty of Biology, Medicine and Health, University of Manchester, Manchester M13 9NT, UK
| |
Collapse
|
11
|
Severn-Ellis AA, Schoeman MH, Bayer PE, Hane JK, Rees DJG, Edwards D, Batley J. Genome Analysis of the Broad Host Range Necrotroph Nalanthamala psidii Highlights Genes Associated With Virulence. FRONTIERS IN PLANT SCIENCE 2022; 13:811152. [PMID: 35283890 PMCID: PMC8914235 DOI: 10.3389/fpls.2022.811152] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 11/08/2021] [Accepted: 01/18/2022] [Indexed: 06/14/2023]
Abstract
Guava wilt disease is caused by the fungus Nalanthamala psidii. The wilt disease results in large-scale destruction of orchards in South Africa, Taiwan, and several Southeast Asian countries. De novo assembly, annotation, and in-depth analysis of the N. psidii genome were carried out to facilitate the identification of characteristics associated with pathogenicity and pathogen evolution. The predicted secretome revealed a range of CAZymes, proteases, lipases and peroxidases associated with plant cell wall degradation, nutrient acquisition, and disease development. Further analysis of the N. psidii carbohydrate-active enzyme profile exposed the broad-spectrum necrotrophic lifestyle of the pathogen, which was corroborated by the identification of putative effectors and secondary metabolites with the potential to induce tissue necrosis and cell surface-dependent immune responses. Putative regulatory proteins including transcription factors and kinases were identified in addition to transporters potentially involved in the secretion of secondary metabolites. Transporters identified included important ABC and MFS transporters involved in the efflux of fungicides. Analysis of the repetitive landscape and the detection of mechanisms linked to reproduction such as het and mating genes rendered insights into the biological complexity and evolutionary potential of N. psidii as guava pathogen. Hence, the assembly and annotation of the N. psidii genome provided a valuable platform to explore the pathogenic potential and necrotrophic lifestyle of the guava wilt pathogen.
Collapse
Affiliation(s)
- Anita A. Severn-Ellis
- School of Biological Sciences, Institute of Agriculture, The University of Western Australia, Crawley, WA, Australia
- Aquaculture Research and Development, Department of Primary Industries and Regional Development, Indian Ocean Marine Research Centre, Watermans Bay, WA, Australia
| | - Maritha H. Schoeman
- Institute for Tropical and Subtropical Crops, Agricultural Research Council, Nelspruit, South Africa
| | - Philipp E. Bayer
- School of Biological Sciences, Institute of Agriculture, The University of Western Australia, Crawley, WA, Australia
| | - James K. Hane
- Centre for Crop and Disease Management, School of Molecular and Life Sciences, Curtin University, Bentley, WA, Australia
| | - D. Jasper G. Rees
- Agricultural Research Council, Biotechnology Platform, Pretoria, South Africa
- Botswana University of Agriculture and Natural Resources, Gaborone, Botswana
| | - David Edwards
- School of Biological Sciences, Institute of Agriculture, The University of Western Australia, Crawley, WA, Australia
| | - Jacqueline Batley
- School of Biological Sciences, Institute of Agriculture, The University of Western Australia, Crawley, WA, Australia
| |
Collapse
|
12
|
Jiao W, Yu H, Cong J, Xiao K, Zhang X, Liu J, Zhang Y, Pan H. Transcription factor SsFoxE3 activating SsAtg8 is critical for sclerotia, compound appressoria formation, and pathogenicity in Sclerotinia sclerotiorum. MOLECULAR PLANT PATHOLOGY 2022; 23:204-217. [PMID: 34699137 PMCID: PMC8743022 DOI: 10.1111/mpp.13154] [Citation(s) in RCA: 12] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/24/2021] [Revised: 09/22/2021] [Accepted: 10/07/2021] [Indexed: 06/13/2023]
Abstract
Sclerotinia sclerotiorum, the notorious necrotrophic phytopathogenic fungus with wide distribution, is responsible for sclerotium disease in more than 600 plant species, including many economic crops such as soybean, oilseed rape, and sunflower. The compound appressorium is a crucial multicellular infection structure that is a prerequisite for infecting healthy tissues. Previously, the Forkhead-box family transcription factors (FOX TFs) SsFoxE2 and SsFKH1 were shown to play a key regulatory role in the hyphae growth, sexual reproduction, and pathogenicity of S. sclerotiorum. However, little is known about the roles of SsFoxE3 regulating growth and development and pathogenicity. Here, we report SsFoxE3 contributes to sclerotium formation and deletion of SsFoxE3 leads to reduced formation of compound appressoria and developmental delays. Transcripts of SsFoxE3 were greatly increased during the initial stage of infection and SsFoxE3 deficiency reduced virulence on the host, while stabbing inoculation could partially restore pathogenicity. The SsFoxE3 mutant showed sensitivity to H2 O2 , and the expression of reactive oxygen species detoxification and autophagy-related genes were reduced. Moreover, expression of SsAtg8 was also decreased during the infection process of the SsFoxE3 mutant. Yeast 1-hybrid tests suggested that SsFoxE3 interacted with the promoter of SsAtg8. Disruption of SsAtg8 resulted in a phenotype similar to that of the SsFoxE3 mutant. Comparative analysis of the level of autophagy in the wild type and SsFoxE3 mutant showed that N starvation-induced autophagy was reduced in the SsFoxE3 mutant. Taken together, our findings indicate that SsFoxE3 plays an important role in compound appressorium formation and is involved in transcriptional activation of SsAtg8 during infection by S. sclerotiorum.
Collapse
Affiliation(s)
- Wenli Jiao
- College of Plant SciencesJilin UniversityChangchunChina
| | - Huilin Yu
- College of Plant SciencesJilin UniversityChangchunChina
| | - Jie Cong
- College of Plant SciencesJilin UniversityChangchunChina
| | - Kunqin Xiao
- College of Plant SciencesJilin UniversityChangchunChina
| | | | - Jinliang Liu
- College of Plant SciencesJilin UniversityChangchunChina
| | - Yanhua Zhang
- College of Plant SciencesJilin UniversityChangchunChina
| | - Hongyu Pan
- College of Plant SciencesJilin UniversityChangchunChina
| |
Collapse
|
13
|
Ceballos-Garzon A, Monteoliva L, Gil C, Alvarez-Moreno C, Vega-Vela NE, Engelthaler DM, Bowers J, Le Pape P, Parra-Giraldo CM. Genotypic, proteomic, and phenotypic approaches to decipher the response to caspofungin and calcineurin inhibitors in clinical isolates of echinocandin-resistant Candida glabrata. J Antimicrob Chemother 2021; 77:585-597. [PMID: 34893830 PMCID: PMC8865013 DOI: 10.1093/jac/dkab454] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2021] [Accepted: 11/09/2021] [Indexed: 01/20/2023] Open
Abstract
Background Echinocandin resistance represents a great concern, as these drugs are recommended as first-line therapy for invasive candidiasis. Echinocandin resistance is conferred by mutations in FKS genes. Nevertheless, pathways are crucial for enabling tolerance, evolution, and maintenance of resistance. Therefore, understanding the biological processes and proteins involved in the response to caspofungin may provide clues indicating new therapeutic targets. Objectives We determined the resistance mechanism and assessed the proteome response to caspofungin exposure. We then evaluated the phenotypic impact of calcineurin inhibition by FK506 and cephalosporine A (CsA) on caspofungin-resistant Candida glabrata isolates. Methods Twenty-five genes associated with caspofungin resistance were analysed by NGS, followed by studies of the quantitative proteomic response to caspofungin exposure. Then, susceptibility testing of caspofungin in presence of FK506 and CsA was performed. The effects of calcineurin inhibitor/caspofungin combinations on heat stress (40°C), oxidative stress (0.2 and 0.4 mM menadione) and on biofilm formation (polyurethane catheter) were analysed. Finally, a Galleria mellonella model using blastospores (1 × 109 cfu/mL) was developed to evaluate the impact of the combinations on larval survival. Results F659-del was found in the FKS2 gene of resistant strains. Proteomics data showed some up-regulated proteins are involved in cell-wall biosynthesis, response to stress and pathogenesis, some of them being members of calmodulin–calcineurin pathway. Therefore, the impact of calmodulin inhibition was explored. Calmodulin inhibition restored caspofungin susceptibility, decreased capacity to respond to stress conditions, and reduced biofilm formation and in vivo pathogenicity. Conclusions Our findings confirm that calmodulin-calcineurin-Crz1 could provide a relevant target in life-threatening invasive candidiasis.
Collapse
Affiliation(s)
- Andres Ceballos-Garzon
- Unidad de Proteómica y Micosis Humanas, Grupo de Enfermedades Infecciosas Departamento de Microbiología, Facultad de Ciencias, Pontificia Universidad Javeriana, Bogotá, D.C., Colombia
- Department of Parasitology and Medical Mycology, Faculty of Pharmacy, University of Nantes, Nantes Atlantique Universities, Nantes, France
| | - Lucia Monteoliva
- Departamento de Microbiología y Parasitología, Facultad de Farmacia, Universidad Complutense de Madrid, Madrid, Spain
| | - Concha Gil
- Departamento de Microbiología y Parasitología, Facultad de Farmacia, Universidad Complutense de Madrid, Madrid, Spain
- Unidad de Proteómica, Universidad Complutense de Madrid, Madrid, Spain
| | - Carlos Alvarez-Moreno
- Department of Internal Medicine, Faculty of Medicine, Universidad Nacional de Colombia, Bogotá, Colombia
- Clínica Universitaria Colombia, Clinica Colsanitas, Bogotá, Colombia
| | - Nelson E Vega-Vela
- Unidad de Proteómica y Micosis Humanas, Grupo de Enfermedades Infecciosas Departamento de Microbiología, Facultad de Ciencias, Pontificia Universidad Javeriana, Bogotá, D.C., Colombia
| | | | - Jolene Bowers
- Translational Genomics Research Institute, Flagstaff, AZ, USA
| | - Patrice Le Pape
- Department of Parasitology and Medical Mycology, Faculty of Pharmacy, University of Nantes, Nantes Atlantique Universities, Nantes, France
| | - Claudia M Parra-Giraldo
- Unidad de Proteómica y Micosis Humanas, Grupo de Enfermedades Infecciosas Departamento de Microbiología, Facultad de Ciencias, Pontificia Universidad Javeriana, Bogotá, D.C., Colombia
- Corresponding author. E-mail:
| |
Collapse
|
14
|
Amsri A, Jeenkeawpieam J, Sukantamala P, Pongpom M. Role of acuK in Control of Iron Acquisition and Gluconeogenesis in Talaromyces marneffei. J Fungi (Basel) 2021; 7:jof7100798. [PMID: 34682218 PMCID: PMC8539426 DOI: 10.3390/jof7100798] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2021] [Revised: 09/21/2021] [Accepted: 09/21/2021] [Indexed: 01/03/2023] Open
Abstract
Talaromyces marneffei is a dimorphic pathogenic fungus causing opportunistic infection in immunocompromised patients. It is a facultative intracellular pathogen and is usually found inside the host macrophages during infection. Alternative carbons and iron are the important nutrients associated with intracellular survival and pathogenesis of T. marneffei. This study reported the importance of the transcription factor AcuK in control of gluconeogenesis and iron acquisition in T. marneffei. Deletion of acuK gene in T. marneffei resulted in retardation of growth and germination in both mold and yeast phases. Microscopically, ΔacuK showed double nuclei hyphae. However, the yeast cells showed normal morphology. The ΔacuK failed to grow in iron-limiting conditions. Additionally, it could not grow in a medium containing gluconeogenic carbon sources. Moreover, ΔacuK showed higher susceptibility to macrophage killing than the wild type. These results demonstrated that AcuK controlled both iron acquisition and gluconeogenesis, and it could contribute to the pathogenicity of this fungus.
Collapse
|
15
|
John E, Singh KB, Oliver RP, Tan K. Transcription factor control of virulence in phytopathogenic fungi. MOLECULAR PLANT PATHOLOGY 2021; 22:858-881. [PMID: 33973705 PMCID: PMC8232033 DOI: 10.1111/mpp.13056] [Citation(s) in RCA: 37] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/22/2020] [Revised: 03/02/2021] [Accepted: 03/04/2021] [Indexed: 05/12/2023]
Abstract
Plant-pathogenic fungi are a significant threat to economic and food security worldwide. Novel protection strategies are required and therefore it is critical we understand the mechanisms by which these pathogens cause disease. Virulence factors and pathogenicity genes have been identified, but in many cases their roles remain elusive. It is becoming increasingly clear that gene regulation is vital to enable plant infection and transcription factors play an essential role. Efforts to determine their regulatory functions in plant-pathogenic fungi have expanded since the annotation of fungal genomes revealed the ubiquity of transcription factors from a broad range of families. This review establishes the significance of transcription factors as regulatory elements in plant-pathogenic fungi and provides a systematic overview of those that have been functionally characterized. Detailed analysis is provided on regulators from well-characterized families controlling various aspects of fungal metabolism, development, stress tolerance, and the production of virulence factors such as effectors and secondary metabolites. This covers conserved transcription factors with either specialized or nonspecialized roles, as well as recently identified regulators targeting key virulence pathways. Fundamental knowledge of transcription factor regulation in plant-pathogenic fungi provides avenues to identify novel virulence factors and improve our understanding of the regulatory networks linked to pathogen evolution, while transcription factors can themselves be specifically targeted for disease control. Areas requiring further insight regarding the molecular mechanisms and/or specific classes of transcription factors are identified, and direction for future investigation is presented.
Collapse
Affiliation(s)
- Evan John
- Centre for Crop and Disease ManagementCurtin UniversityBentleyWestern AustraliaAustralia
- School of Molecular and Life SciencesCurtin UniversityBentleyWestern AustraliaAustralia
| | - Karam B. Singh
- Agriculture and FoodCommonwealth Scientific and Industrial Research OrganisationFloreatWestern AustraliaAustralia
| | - Richard P. Oliver
- School of Molecular and Life SciencesCurtin UniversityBentleyWestern AustraliaAustralia
| | - Kar‐Chun Tan
- Centre for Crop and Disease ManagementCurtin UniversityBentleyWestern AustraliaAustralia
- School of Molecular and Life SciencesCurtin UniversityBentleyWestern AustraliaAustralia
| |
Collapse
|
16
|
Villa S, Hamideh M, Weinstock A, Qasim MN, Hazbun TR, Sellam A, Hernday AD, Thangamani S. Transcriptional control of hyphal morphogenesis in Candida albicans. FEMS Yeast Res 2021; 20:5715912. [PMID: 31981355 PMCID: PMC7000152 DOI: 10.1093/femsyr/foaa005] [Citation(s) in RCA: 38] [Impact Index Per Article: 12.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2019] [Accepted: 01/31/2020] [Indexed: 12/12/2022] Open
Abstract
Candida albicans is a multimorphic commensal organism and opportunistic fungal pathogen in humans. A morphological switch between unicellular budding yeast and multicellular filamentous hyphal growth forms plays a vital role in the virulence of C. albicans, and this transition is regulated in response to a range of environmental cues that are encountered in distinct host niches. Many unique transcription factors contribute to the transcriptional regulatory network that integrates these distinct environmental cues and determines which phenotypic state will be expressed. These hyphal morphogenesis regulators have been extensively investigated, and represent an increasingly important focus of study, due to their central role in controlling a key C. albicans virulence attribute. This review provides a succinct summary of the transcriptional regulatory factors and environmental signals that control hyphal morphogenesis in C. albicans.
Collapse
Affiliation(s)
- Sonia Villa
- Masters in Biomedical Science Program, Midwestern University, 19555 N. 59th Ave. Glendale, AZ 85308, USA
| | - Mohammad Hamideh
- Masters in Biomedical Science Program, Midwestern University, 19555 N. 59th Ave. Glendale, AZ 85308, USA
| | - Anthony Weinstock
- Arizona College of Osteopathic Medicine, Midwestern University, 19555 N. 59th Ave. Glendale, AZ 85308, USA
| | - Mohammad N Qasim
- Quantitative and Systems Biology Graduate Program, School of Natural Sciences, University of California, Merced, Merced, CA, 95343, USA
| | - Tony R Hazbun
- Department of Medicinal Chemistry and Molecular Pharmacology, College of Pharmacy, Purdue University, West Lafayette, IN 47907, USA
| | - Adnane Sellam
- Department of Microbiology, Infectious Diseases and Immunology, Faculty of Medicine, Université Laval, Quebec City, QC, Canada
| | - Aaron D Hernday
- Quantitative and Systems Biology Graduate Program, School of Natural Sciences, University of California, Merced, Merced, CA, 95343, USA.,Department of Molecular and Cell Biology, School of Natural Sciences, University of California, Merced, Merced, CA, 95343, USA
| | - Shankar Thangamani
- Department of Pathology and Population Medicine, College of Veterinary Medicine, Midwestern University, 19555 N. 59th Ave. Glendale, AZ 85308, USA
| |
Collapse
|
17
|
Rossi A, Martins MP, Bitencourt TA, Peres NTA, Rocha CHL, Rocha FMG, Neves-da-Rocha J, Lopes MER, Sanches PR, Bortolossi JC, Martinez-Rossi NM. Reassessing the Use of Undecanoic Acid as a Therapeutic Strategy for Treating Fungal Infections. Mycopathologia 2021; 186:327-340. [PMID: 33835367 DOI: 10.1007/s11046-021-00550-4] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2020] [Accepted: 03/21/2021] [Indexed: 12/15/2022]
Abstract
Treating fungal infections is challenging and frequently requires long-term courses of antifungal drugs. Considering the limited number of existing antifungal drugs, it is crucial to evaluate the possibility of repositioning drugs with antifungal properties and to revisit older antifungals for applications in combined therapy, which could widen the range of therapeutic possibilities. Undecanoic acid is a saturated medium-chain fatty acid with known antifungal effects; however, its antifungal properties have not been extensively explored. Recent advances indicate that the toxic effect of undecanoic acid involves modulation of fungal metabolism through its effects on the expression of fungal genes that are critical for virulence. Additionally, undecanoic acid is suitable for chemical modification and might be useful in synergic therapies. This review highlights the use of undecanoic acid in antifungal treatments, reinforcing its known activity against dermatophytes. Specifically, in Trichophyton rubrum, against which the activity of undecanoic acid has been most widely studied, undecanoic acid elicits profound effects on pivotal processes in the cell wall, membrane assembly, lipid metabolism, pathogenesis, and even mRNA processing. Considering the known antifungal activities and associated mechanisms of undecanoic acid, its potential use in combination therapy, and the ability to modify the parent compound structure, undecanoic acid shows promise as a novel therapeutic against fungal infections.
Collapse
Affiliation(s)
- Antonio Rossi
- Department of Genetics, Ribeirão Preto Medical School, University of São Paulo, USP, Ribeirão Preto, SP, 14049-900, Brazil
| | - Maíra P Martins
- Department of Genetics, Ribeirão Preto Medical School, University of São Paulo, USP, Ribeirão Preto, SP, 14049-900, Brazil
| | - Tamires A Bitencourt
- Department of Genetics, Ribeirão Preto Medical School, University of São Paulo, USP, Ribeirão Preto, SP, 14049-900, Brazil
| | - Nalu T A Peres
- Department of Microbiology, Institute of Biological Sciences, Federal University of Minas Gerais, Belo Horizonte, MG, Brazil
| | - Carlos H L Rocha
- Department of Genetics, Ribeirão Preto Medical School, University of São Paulo, USP, Ribeirão Preto, SP, 14049-900, Brazil
| | - Flaviane M G Rocha
- Department of Genetics, Ribeirão Preto Medical School, University of São Paulo, USP, Ribeirão Preto, SP, 14049-900, Brazil
| | - João Neves-da-Rocha
- Department of Genetics, Ribeirão Preto Medical School, University of São Paulo, USP, Ribeirão Preto, SP, 14049-900, Brazil
| | - Marcos E R Lopes
- Department of Genetics, Ribeirão Preto Medical School, University of São Paulo, USP, Ribeirão Preto, SP, 14049-900, Brazil
| | - Pablo R Sanches
- Department of Genetics, Ribeirão Preto Medical School, University of São Paulo, USP, Ribeirão Preto, SP, 14049-900, Brazil
| | - Júlio C Bortolossi
- Department of Genetics, Ribeirão Preto Medical School, University of São Paulo, USP, Ribeirão Preto, SP, 14049-900, Brazil
| | - Nilce M Martinez-Rossi
- Department of Genetics, Ribeirão Preto Medical School, University of São Paulo, USP, Ribeirão Preto, SP, 14049-900, Brazil.
| |
Collapse
|
18
|
Liu H, Xu W, Bruno VM, Phan QT, Solis NV, Woolford CA, Ehrlich RL, Shetty AC, McCraken C, Lin J, Bromley MJ, Mitchell AP, Filler SG. Determining Aspergillus fumigatus transcription factor expression and function during invasion of the mammalian lung. PLoS Pathog 2021; 17:e1009235. [PMID: 33780518 PMCID: PMC8031882 DOI: 10.1371/journal.ppat.1009235] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2020] [Revised: 04/08/2021] [Accepted: 03/20/2021] [Indexed: 12/14/2022] Open
Abstract
To gain a better understanding of the transcriptional response of Aspergillus fumigatus during invasive pulmonary infection, we used a NanoString nCounter to assess the transcript levels of 467 A. fumigatus genes during growth in the lungs of immunosuppressed mice. These genes included ones known to respond to diverse environmental conditions and those encoding most transcription factors in the A. fumigatus genome. We found that invasive growth in vivo induces a unique transcriptional profile as the organism responds to nutrient limitation and attack by host phagocytes. This in vivo transcriptional response is largely mimicked by in vitro growth in Aspergillus minimal medium that is deficient in nitrogen, iron, and/or zinc. From the transcriptional profiling data, we selected 9 transcription factor genes that were either highly expressed or strongly up-regulated during in vivo growth. Deletion mutants were constructed for each of these genes and assessed for virulence in mice. Two transcription factor genes were found to be required for maximal virulence. One was rlmA, which is required for the organism to achieve maximal fungal burden in the lung. The other was sltA, which regulates of the expression of multiple secondary metabolite gene clusters and mycotoxin genes independently of laeA. Using deletion and overexpression mutants, we determined that the attenuated virulence of the ΔsltA mutant is due in part to decreased expression aspf1, which specifies a ribotoxin, but is not mediated by reduced expression of the fumigaclavine gene cluster or the fumagillin-pseruotin supercluster. Thus, in vivo transcriptional profiling focused on transcription factors genes provides a facile approach to identifying novel virulence regulators. Although A. fumigatus causes the majority of cases of invasive aspergillosis, the function of most genes in its genome remains unknown. To identify genes encoding transcription factors that may be important for virulence, we used a NanoString nCounter to measure the mRNA levels of A. fumigatus transcription factor genes in the lungs of mice with invasive aspergillosis. The transcriptional profiling data indicate that the organism is exposed to nutrient limitation and stress during growth in the lungs, and that it responds by up-regulating genes that encode mycotoxins and secondary metabolites. In vitro, this response was most closely mimicked by growth in medium that was deficient in nitrogen, iron and/or zinc. Using the transcriptional profiling data, we identified two transcription factors that govern A. fumigatus virulence. These were RlmA, which is governs factors that enables the organism to proliferate maximally in the lung and SltA, which controls the production of mycotoxins and secondary metabolites.
Collapse
Affiliation(s)
- Hong Liu
- Division of Infectious Diseases, Lundquist Institute for Biomedical Innovation at Harbor-UCLA Medical Center, Torrance, CA, United States of America
| | - Wenjie Xu
- Department of Biological Sciences, Carnegie Mellon University, Pittsburgh, PA, United States of America
| | - Vincent M. Bruno
- Department of Microbiology and Immunology, University of Maryland, Baltimore, MD, United States of America
| | - Quynh T. Phan
- Division of Infectious Diseases, Lundquist Institute for Biomedical Innovation at Harbor-UCLA Medical Center, Torrance, CA, United States of America
| | - Norma V. Solis
- Division of Infectious Diseases, Lundquist Institute for Biomedical Innovation at Harbor-UCLA Medical Center, Torrance, CA, United States of America
| | - Carol A. Woolford
- Department of Biological Sciences, Carnegie Mellon University, Pittsburgh, PA, United States of America
| | - Rachel L. Ehrlich
- Department of Biological Sciences, Carnegie Mellon University, Pittsburgh, PA, United States of America
| | - Amol C. Shetty
- Institute for Genome Sciences, University of Maryland, Baltimore, MD, United States of America
| | - Carrie McCraken
- Institute for Genome Sciences, University of Maryland, Baltimore, MD, United States of America
| | - Jianfeng Lin
- Division of Infectious Diseases, Lundquist Institute for Biomedical Innovation at Harbor-UCLA Medical Center, Torrance, CA, United States of America
| | - Michael J. Bromley
- Manchester Fungal Infection Group, Faculty of Biology, Medicine and Health, The University of Manchester, Manchester Academic Health Science Centre, Core Technology Facility, and Lydia Becker Institute of Immunology and Inflammation, Biology, Medicine and Health. The University of Manchester, Manchester Academic Health Science Centre, MA, United Kingdom
| | - Aaron P. Mitchell
- Department of Biological Sciences, Carnegie Mellon University, Pittsburgh, PA, United States of America
- Department of Microbiology, University of Georgia, Athens, GA, United States of America
- * E-mail: (APM); (SGF)
| | - Scott G. Filler
- Division of Infectious Diseases, Lundquist Institute for Biomedical Innovation at Harbor-UCLA Medical Center, Torrance, CA, United States of America
- David Geffen School of Medicine at UCLA, Los Angeles, CA, United States of America
- * E-mail: (APM); (SGF)
| |
Collapse
|
19
|
Efg1 and Cas5 Orchestrate Cell Wall Damage Response to Caspofungin in Candida albicans. Antimicrob Agents Chemother 2021; 65:AAC.01584-20. [PMID: 33168610 DOI: 10.1128/aac.01584-20] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2020] [Accepted: 11/01/2020] [Indexed: 01/27/2023] Open
Abstract
Echinocandins are recommended as the first-line drugs for the treatment of systemic candidiasis. Cas5 is a key transcription factor involved in the response to cell wall damage induced by echinocandins. In this study, through a genetic screen, we identified a second transcription factor, Efg1, that is also crucial for proper transcriptional responses to echinocandins. Like CAS5, deletion of EFG1 confers hypersensitivity to caspofungin. Efg1 is required for the induction of CAS5 in response to caspofungin. However, ectopically expressed CAS5 cannot rescue the growth defect of efg1 mutant in caspofungin-containing medium. Deleting EFG1 in the cas5 mutant exacerbates the cell wall stress upon caspofungin addition and renders caspofungin-resistant Candida albicans responsive to treatment. Genome-wide transcription profiling of efg1/efg1 and cas5/cas5 using transcriptome sequencing (RNA-Seq) indicates that Efg1 and Cas5 coregulate caspofungin-responsive gene expression, but they also independently control induction of some genes. We further show that Efg1 interacts with Cas5 by yeast two-hybrid and in vivo immunoprecipitation in the presence or absence of caspofungin. Importantly, Efg1 and Cas5 bind to some caspofungin-responsive gene promoters to coordinately activate their expression. Thus, we demonstrate that Efg1, together with Cas5, controls the transcriptional response to cell wall stress induced by caspofungin.
Collapse
|
20
|
Transcriptional regulation of the caspofungin-induced cell wall damage response in Candida albicans. Curr Genet 2020; 66:1059-1068. [PMID: 32876716 DOI: 10.1007/s00294-020-01105-8] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2020] [Revised: 08/14/2020] [Accepted: 08/25/2020] [Indexed: 12/14/2022]
Abstract
The human fungal pathogen Candida albicans maintains pathogenic and commensal states primarily through cell wall functions. The echinocandin antifungal drug caspofungin inhibits cell wall synthesis and is widely used in treating disseminated candidiasis. Signaling pathways are critical in coordinating the adaptive response to cell wall damage (CWD). C. albicans executes a robust transcriptional program following caspofungin-induced CWD. A comprehensive analysis of signaling pathways at the transcriptional level facilitates the identification of prospective genes for functional characterization and propels the development of novel antifungal interventions. This review article focuses on the molecular functions and signaling crosstalk of the C. albicans transcription factors Sko1, Rlm1, and Cas5 in caspofungin-induced CWD signaling.
Collapse
|
21
|
Novel 2,4-Disubstituted-1,3-Thiazole Derivatives: Synthesis, Anti- Candida Activity Evaluation and Interaction with Bovine Serum Albumine. Molecules 2020; 25:molecules25051079. [PMID: 32121062 PMCID: PMC7179180 DOI: 10.3390/molecules25051079] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2020] [Revised: 02/24/2020] [Accepted: 02/26/2020] [Indexed: 12/29/2022] Open
Abstract
Herein we report the synthesis of two novel series of 1,3-thiazole derivatives having a lipophilic C4-substituent on account of the increasing need for novel and versatile antifungal drugs for the treatment of resistant Candida sp.-based infections. Following their structural characterization, the anti-Candida activity was evaluated in vitro while using the broth microdilution method. Three compounds exhibited lower Minimum Inhibitory Concentration (MIC) values when compared to fluconazole, being used as the reference antifungal drug. An in silico molecular docking study was subsequently carried out in order to gain more insight into the antifungal mechanism of action, while using lanosterol-C14α-demethylase as the target enzyme. Fluorescence microscopy was employed to further investigate the cellular target of the most promising molecule, with the obtained results confirming its damaging effect towards the fungal cell membrane integrity. Finally, the distribution and the pharmacological potential in vivo of the novel thiazole derivatives was investigated through the study of their binding interaction with bovine serum albumin, while using fluorescence spectroscopy.
Collapse
|
22
|
Derivatives of the Antimalarial Drug Mefloquine Are Broad-Spectrum Antifungal Molecules with Activity against Drug-Resistant Clinical Isolates. Antimicrob Agents Chemother 2020; 64:AAC.02331-19. [PMID: 31907188 DOI: 10.1128/aac.02331-19] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2019] [Accepted: 12/20/2019] [Indexed: 12/21/2022] Open
Abstract
The antifungal pharmacopeia is critically small, particularly in light of the recent emergence of multidrug-resistant pathogens, such as Candida auris Here, we report that derivatives of the antimalarial drug mefloquine have broad-spectrum antifungal activity against pathogenic yeasts and molds. In addition, the mefloquine derivatives have activity against clinical isolates that are resistant to one or more of the three classes of antifungal drugs currently used to treat invasive fungal infections, indicating that they have a novel mechanism of action. Importantly, the in vitro toxicity profiles obtained using human cell lines indicated that the toxicity profiles of the mefloquine derivatives are very similar to those of the parent mefloquine, despite being up to 64-fold more active against fungal cells. In addition to direct antifungal activity, subinhibitory concentrations of the mefloquine derivatives inhibited the expression of virulence traits, including filamentation in Candida albicans and capsule formation/melanization in Cryptococcus neoformans Mode/mechanism-of-action experiments indicated that the mefloquine derivatives interfere with both mitochondrial and vacuolar function as part of a multitarget mechanism of action. The broad-spectrum scope of activity, blood-brain barrier penetration, and large number of previously synthesized analogs available combine to support the further optimization and development of the antifungal activity of this general class of drug-like molecules.
Collapse
|
23
|
Abstract
Candida albicans has remained the main etiological agent of candidiasis, challenges clinicians with high mortality and morbidity. The emergence of resistance to antifungal drugs, toxicity and lower efficacy have all contributed to an urgent need to develop alternative drugs aiming at novel targets in C. albicans. Targeting the production of virulence factors, which are essential processes for infectious agents, represents an attractive substitute for the development of newer anti-infectives. The present review highlights the recent developments made in the understanding of the pathogenicity of C. albicans. Production of hydrolytic enzymes, morphogenesis and biofilm formation, along with their molecular and metabolic regulation in Candida are discussed with regard to the development of novel antipathogenic drugs against candidiasis. Over the last decade, candidiasis has remained a major problematic disease worldwide. In spite of the existence of many antifungal drugs, the treatment of such diseases has still remained unsuccessful due to drug inefficacy. Therefore, there is a need to discover antifungals with different modes of action, such as antipathogenic drugs against Candida albicans. Here, we describe how various types of virulence factors such as proteinase, phospholipase, hemolysin, adhesion, morphogenesis and biofilm formation, could be targeted to develop novel therapeutics. We can inhibit production of these virulence factors by controlling their molecular/metabolic regulation.
Collapse
|
24
|
Ma F, Zhu Y, Liu X, Zhou Q, Hong X, Qu C, Feng X, Zhang Y, Ding Q, Zhao J, Hou J, Zhong M, Zhuo H, Zhong L, Ye Z, Xie W, Liu Y, Xiong Y, Chen H, Piao D, Sun B, Gao Z, Li Q, Zhang Z, Qiu X, Zhang Z. Dual-Specificity Tyrosine Phosphorylation-Regulated Kinase 3 Loss Activates Purine Metabolism and Promotes Hepatocellular Carcinoma Progression. Hepatology 2019; 70:1785-1803. [PMID: 31066068 DOI: 10.1002/hep.30703] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/26/2018] [Accepted: 04/12/2019] [Indexed: 12/14/2022]
Abstract
Cancer cells metabolize different energy sources to generate biomass rapidly. The purine biosynthetic pathway was recently identified as an important source of metabolic intermediates for these processes. However, very little was known about the regulatory mechanisms of purine metabolism in hepatocellular carcinoma (HCC). We explored the role of dual-specificity tyrosine (Y) phosphorylation-regulated kinase 3 (Dyrk3) in HCC metabolism. Dyrk3 was significantly down-regulated in HCC compared with normal controls. Its introduction in HCC cells markedly suppressed tumor growth and metastasis in xenograft tumor models. Mass spectrometric analysis of metabolites suggests that the effect of Dyrk3 on HCC occurred at least partially through down-regulating purine metabolism, as evidenced by the fact that inhibiting purine synthesis reverted the HCC progression mediated by the loss of Dyrk3. We further provide evidence that this action of Dyrk3 knockdown requires nuclear receptor coactivator 3 (NCOA3), which has been shown to be a coactivator of activating transcription factor 4 (ATF4) to target purine pathway genes for transcriptional activation. Mechanistically, Dyrk3 directly phosphorylated NCOA3 at Ser-1330, disrupting its binding to ATF4 and thereby causing the inhibition of ATF4 transcriptional activity. However, the phosphorylation-resistant NCOA3-S1330A mutant has the opposite effect. Interestingly, the promoter activity of Dyrk3 was negatively regulated by ATF4, indicating a double-negative feedback loop. Importantly, levels of Dyrk3 and phospho-NCOA3-S1330 inversely correlate with the expression of ATF4 in human HCC specimens. Conclusion: Our findings not only illustrate a function of Dyrk3 in reprograming HCC metabolism by negatively regulating NCOA3/ATF4 transcription factor complex but also identify NCOA3 as a phosphorylation substrate of Dyrk3, suggesting the Dyrk3/NCOA3/ATF4 axis as a potential candidate for HCC therapy.
Collapse
Affiliation(s)
- Fei Ma
- The affiliated Hospital of Guilin Medical University, Guangxi Key Laboratory of Brain and Cognitive Neuroscience, Guangxi Neurological Diseases Clinical Research Center, Guilin, Guangxi, China.,Department of General Surgery, The Second Affiliated Hospital of Harbin Medical University, Harbin, China.,Cancer Institute of New Jersey, Rutgers University, New Brunswick, NJ
| | - Yuekun Zhu
- Department of General Surgery, The First Affiliated Hospital of Harbin Medical University, Harbin, China.,Medical Center, Duke University, Durham, NC
| | - Xing Liu
- Department of Neurosurgery, Beijing Tiantan Hospital, Capital Medical University, Beijing, China
| | - Qingxin Zhou
- Department of Gastrointestinal Oncology, Harbin Medical University Cancer Hospital, Harbin, China
| | - Xuehui Hong
- Department of Gastrointestinal Surgery, Zhongshan Hospital of Xiamen University, Xiamen, China
| | - Chao Qu
- Department of Radiation Oncology, The First Hospital of Jilin University, Changchun, China
| | - Xing Feng
- Cancer Institute of New Jersey, Rutgers University, New Brunswick, NJ
| | - Yiyun Zhang
- Department of Endoscopy, Harbin Medical University Cancer Hospital, Harbin, China
| | - Qingbin Ding
- Department of Operation, The First Affiliated Hospital of Harbin Medical University, Harbin, China
| | - Jiabao Zhao
- Department of Gastrointestinal Surgery, Zhongshan Hospital of Xiamen University, Xiamen, China
| | - Jingjing Hou
- Department of Gastrointestinal Surgery, Zhongshan Hospital of Xiamen University, Xiamen, China
| | - Mengya Zhong
- Department of Gastrointestinal Surgery, Zhongshan Hospital of Xiamen University, Xiamen, China
| | - Huiqin Zhuo
- Department of Gastrointestinal Surgery, Zhongshan Hospital of Xiamen University, Xiamen, China
| | - Lifeng Zhong
- Department of Gastrointestinal Surgery, Zhongshan Hospital of Xiamen University, Xiamen, China
| | - Zhijian Ye
- Department of Gastrointestinal Surgery, Zhongshan Hospital of Xiamen University, Xiamen, China
| | - Wen Xie
- Department of Gastrointestinal Surgery, Zhongshan Hospital of Xiamen University, Xiamen, China
| | - Yu Liu
- Department of Gastrointestinal Surgery, Zhongshan Hospital of Xiamen University, Xiamen, China
| | - Yubo Xiong
- Department of Gastrointestinal Surgery, Zhongshan Hospital of Xiamen University, Xiamen, China
| | - Hongwei Chen
- Department of Gastrointestinal Surgery, Zhongshan Hospital of Xiamen University, Xiamen, China
| | - Daxun Piao
- Department of General Surgery, The First Affiliated Hospital of Harbin Medical University, Harbin, China
| | - Bei Sun
- Department of General Surgery, The First Affiliated Hospital of Harbin Medical University, Harbin, China
| | - Zhi Gao
- National Center for International Research of Biological Targeting Diagnosis and Therapy (Guangxi Key Laboratory of Biological Targeting Diagnosis and Therapy Research), Guangxi Medical University, Nanning, China
| | - Qinghua Li
- The affiliated Hospital of Guilin Medical University, Guangxi Key Laboratory of Brain and Cognitive Neuroscience, Guangxi Neurological Diseases Clinical Research Center, Guilin, Guangxi, China
| | - Zhen Zhang
- Department of General Surgery, The First Affiliated Anhui of Harbin Medical University, Anhui, China
| | - Xingfeng Qiu
- Department of Gastrointestinal Surgery, Zhongshan Hospital of Xiamen University, Xiamen, China
| | - Zhiyong Zhang
- The affiliated Hospital of Guilin Medical University, Guangxi Key Laboratory of Brain and Cognitive Neuroscience, Guangxi Neurological Diseases Clinical Research Center, Guilin, Guangxi, China.,Department of Surgery, Robert-Wood-Johnson Medical School University Hospital, Rutgers University, The State University of New Jersey, New Brunswick, NJ
| |
Collapse
|
25
|
Gizińska M, Staniszewska M, Ochal Z. Novel Sulfones with Antifungal Properties: Antifungal Activities and Interactions with Candida spp. Virulence Factors. Mini Rev Med Chem 2019; 19:12-21. [PMID: 30246638 DOI: 10.2174/1389557518666180924121209] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2018] [Revised: 07/05/2018] [Accepted: 07/09/2018] [Indexed: 02/08/2023]
Abstract
Since candidiasis is so difficult to eradicate with an antifungal treatment and the existing antimycotics display many limitations, hopefully new sulfone derivatives may overcome these deficiencies. It is pertinent to study new strategies such as sulfone derivatives targeting the virulence attributes of C. albicans that differentiate them from the host. During infections, the pathogenic potential of C. albicans relies on the virulence factors as follows: hydrolytic enzymes, transcriptional factors, adhesion, and development of biofilms. In the article we explored how the above-presented C. albicans fitness and virulence attributes provided a robust response to the environmental stress exerted by sulfones upon C. albicans; C. albicans fitness and virulence attributes are fungal properties whose inactivation attenuates virulence. Our understanding of how these mechanisms and factors are inhibited by sulfones has increased over the last years. As lack of toxicity is a prerequisite for medical approaches, sulfones (non-toxic as assessed in vitro and in vivo) may prove to be useful for reducing C. albicans pathogenesis in humans. The antifungal activity of sulfones dealing with these multiple virulence factors and fitness attributes is discussed.
Collapse
Affiliation(s)
- Małgorzata Gizińska
- National Institute of Public Health-National Institute of Hygiene, Chocimska 24, 00-791 Warsaw, Poland
| | - Monika Staniszewska
- National Institute of Public Health-National Institute of Hygiene, Chocimska 24, 00-791 Warsaw, Poland
| | - Zbigniew Ochal
- Faculty of Chemistry, Warsaw University of Technology, Noakowskiego 3, 00-664 Warsaw, Poland
| |
Collapse
|
26
|
Tóth R, Cabral V, Thuer E, Bohner F, Németh T, Papp C, Nimrichter L, Molnár G, Vágvölgyi C, Gabaldón T, Nosanchuk JD, Gácser A. Investigation of Candida parapsilosis virulence regulatory factors during host-pathogen interaction. Sci Rep 2018; 8:1346. [PMID: 29358719 PMCID: PMC5777994 DOI: 10.1038/s41598-018-19453-4] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2017] [Accepted: 01/02/2018] [Indexed: 01/23/2023] Open
Abstract
Invasive candidiasis is among the most life-threatening infections in patients in intensive care units. Although Candida albicans is the leading cause of candidaemia, the incidence of Candida parapsilosis infections is also rising, particularly among the neonates. Due to differences in their biology, these species employ different antifungal resistance and virulence mechanisms and also induce dissimilar immune responses. Previously, it has been suggested that core virulence effecting transcription regulators could be attractive ligands for future antifungal drugs. Although the virulence regulatory mechanisms of C. albicans are well studied, less is known about similar mechanisms in C. parapsilosis. In order to search for potential targets for future antifungal drugs against this species, we analyzed the fungal transcriptome during host-pathogen interaction using an in vitro infection model. Selected genes with high expression levels were further examined through their respective null mutant strains, under conditions that mimic the host environment or influence pathogenicity. As a result, we identified several mutants with relevant pathogenicity affecting phenotypes. During the study we highlight three potentially tractable signaling regulators that influence C. parapsilosis pathogenicity in distinct mechanisms. During infection, CPAR2_100540 is responsible for nutrient acquisition, CPAR2_200390 for cell wall assembly and morphology switching and CPAR2_303700 for fungal viability.
Collapse
Affiliation(s)
- Renáta Tóth
- Department of Microbiology, University of Szeged, Szeged, Hungary
| | - Vitor Cabral
- Departments of Medicine and Microbiology and Immunology, Albert Einstein College of Medicine, New York, NY, USA
| | - Ernst Thuer
- Centre for Genomic Regulation (CRG), Barcelona Institute of Science and Technology, Barcelona, Spain
- Universitat Pompeu Fabra (UPF), Barcelona, Spain
| | - Flóra Bohner
- Department of Microbiology, University of Szeged, Szeged, Hungary
| | - Tibor Németh
- Department of Microbiology, University of Szeged, Szeged, Hungary
| | - Csaba Papp
- Department of Microbiology, University of Szeged, Szeged, Hungary
| | - Leonardo Nimrichter
- Laboratório de Glicobiologia de Eucariotos, Instituto de Microbiologia Professor Paulo de Góes, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brazil
| | - Gergő Molnár
- Department of Microbiology, University of Szeged, Szeged, Hungary
| | - Csaba Vágvölgyi
- Department of Microbiology, University of Szeged, Szeged, Hungary
| | - Toni Gabaldón
- Centre for Genomic Regulation (CRG), Barcelona Institute of Science and Technology, Barcelona, Spain
- Universitat Pompeu Fabra (UPF), Barcelona, Spain
- Institució Catalana de Recerca i Estudis Avançats (ICREA), Barcelona, Spain
| | - Joshua D Nosanchuk
- Departments of Medicine and Microbiology and Immunology, Albert Einstein College of Medicine, New York, NY, USA
| | - Attila Gácser
- Department of Microbiology, University of Szeged, Szeged, Hungary.
| |
Collapse
|
27
|
McCarthy MW, Kontoyiannis DP, Cornely OA, Perfect JR, Walsh TJ. Novel Agents and Drug Targets to Meet the Challenges of Resistant Fungi. J Infect Dis 2017; 216:S474-S483. [PMID: 28911042 DOI: 10.1093/infdis/jix130] [Citation(s) in RCA: 105] [Impact Index Per Article: 15.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
Abstract
The emergence of drug-resistant fungi poses a major threat to human health. Despite advances in preventive, diagnostic, and therapeutic interventions, resistant fungal infections continue to cause significant morbidity and mortality in patients with compromised immunity, underscoring the urgent need for new antifungal agents. In this article, we review the challenges associated with identifying broad-spectrum antifungal drugs and highlight novel targets that could enhance the armamentarium of agents available to treat drug-resistant invasive fungal infections.
Collapse
Affiliation(s)
- Matthew W McCarthy
- Division of General Internal Medicine, Weill Cornell Medicine, New York, New York
| | | | - Oliver A Cornely
- Cologne Excellence Cluster on Cellular Stress Responses in Aging-Associated Diseases (CECAD), Department I of Internal Medicine, Clinical Trials Centre Cologne (ZKS Köln), University of Cologne, Germany
| | - John R Perfect
- Division of Infectious Diseases, Duke University, Durham, North Carolina
| | - Thomas J Walsh
- Transplantation-Oncology Infectious Diseases Program, Weill Cornell Medicine, New York, New York
| |
Collapse
|
28
|
Xie JL, Qin L, Miao Z, Grys BT, Diaz JDLC, Ting K, Krieger JR, Tong J, Tan K, Leach MD, Ketela T, Moran MF, Krysan DJ, Boone C, Andrews BJ, Selmecki A, Ho Wong K, Robbins N, Cowen LE. The Candida albicans transcription factor Cas5 couples stress responses, drug resistance and cell cycle regulation. Nat Commun 2017; 8:499. [PMID: 28894103 PMCID: PMC5593949 DOI: 10.1038/s41467-017-00547-y] [Citation(s) in RCA: 39] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2017] [Accepted: 07/06/2017] [Indexed: 12/16/2022] Open
Abstract
The capacity to coordinate environmental sensing with initiation of cellular responses underpins microbial survival and is crucial for virulence and stress responses in microbial pathogens. Here we define circuitry that enables the fungal pathogen Candida albicans to couple cell cycle dynamics with responses to cell wall stress induced by echinocandins, a front-line class of antifungal drugs. We discover that the C. albicans transcription factor Cas5 is crucial for proper cell cycle dynamics and responses to echinocandins, which inhibit β-1,3-glucan synthesis. Cas5 has distinct transcriptional targets under basal and stress conditions, is activated by the phosphatase Glc7, and can regulate the expression of target genes in concert with the transcriptional regulators Swi4 and Swi6. Thus, we illuminate a mechanism of transcriptional control that couples cell wall integrity with cell cycle regulation, and uncover circuitry governing antifungal drug resistance.Cas5 is a transcriptional regulator of responses to cell wall stress in the fungal pathogen Candida albicans. Here, Xie et al. show that Cas5 also modulates cell cycle dynamics and responses to antifungal drugs.
Collapse
Affiliation(s)
- Jinglin L Xie
- Department of Molecular Genetics, University of Toronto, Toronto, ON, Canada, M5G 1M1
| | - Longguang Qin
- Faculty of Health Sciences, University of Macau, Macau SAR, 999078, China
| | - Zhengqiang Miao
- Faculty of Health Sciences, University of Macau, Macau SAR, 999078, China
| | - Ben T Grys
- Department of Molecular Genetics, University of Toronto, Toronto, ON, Canada, M5G 1M1
- Donnelly Centre for Cellular and Biomolecular Research, University of Toronto, Toronto, ON, Canada, M5S 3E1
| | - Jacinto De La Cruz Diaz
- Department of Microbiology and Immunology, University of Rochester, Rochester, NY, 14642, USA
| | - Kenneth Ting
- Department of Molecular Genetics, University of Toronto, Toronto, ON, Canada, M5G 1M1
| | - Jonathan R Krieger
- The Hospital for Sick Children, SPARC Biocentre, Toronto, ON, Canada, M5G 0A4
| | - Jiefei Tong
- The Hospital for Sick Children, Program in Cell Biology, Peter Gilgan Centre for Research and Learning, Toronto, ON, Canada, M5G 0A4
| | - Kaeling Tan
- Faculty of Health Sciences, University of Macau, Macau SAR, 999078, China
| | - Michelle D Leach
- Department of Molecular Genetics, University of Toronto, Toronto, ON, Canada, M5G 1M1
- Aberdeen Fungal Group, School of Medical Sciences, Institute of Medical Sciences, University of Aberdeen, Foresterhill, Abderdeen, AB252ZD, UK
| | - Troy Ketela
- Department of Molecular Genetics, University of Toronto, Toronto, ON, Canada, M5G 1M1
| | - Michael F Moran
- Department of Molecular Genetics, University of Toronto, Toronto, ON, Canada, M5G 1M1
- The Hospital for Sick Children, SPARC Biocentre, Toronto, ON, Canada, M5G 0A4
- The Hospital for Sick Children, Program in Cell Biology, Peter Gilgan Centre for Research and Learning, Toronto, ON, Canada, M5G 0A4
| | - Damian J Krysan
- Department of Microbiology and Immunology, University of Rochester, Rochester, NY, 14642, USA
- Department of Pediatrics and Microbiology/Immunology, University of Rochester, Rochester, NY, 14642, USA
| | - Charles Boone
- Department of Molecular Genetics, University of Toronto, Toronto, ON, Canada, M5G 1M1
- Donnelly Centre for Cellular and Biomolecular Research, University of Toronto, Toronto, ON, Canada, M5S 3E1
| | - Brenda J Andrews
- Department of Molecular Genetics, University of Toronto, Toronto, ON, Canada, M5G 1M1
- Donnelly Centre for Cellular and Biomolecular Research, University of Toronto, Toronto, ON, Canada, M5S 3E1
| | - Anna Selmecki
- Department of Medical Microbiology and Immunology, Creighton University School of Medicine, Omaha, NE, 68178, USA
| | - Koon Ho Wong
- Faculty of Health Sciences, University of Macau, Macau SAR, 999078, China
| | - Nicole Robbins
- Department of Molecular Genetics, University of Toronto, Toronto, ON, Canada, M5G 1M1
| | - Leah E Cowen
- Department of Molecular Genetics, University of Toronto, Toronto, ON, Canada, M5G 1M1.
| |
Collapse
|
29
|
Domínguez Á, Muñoz E, López MC, Cordero M, Martínez JP, Viñas M. Transcriptomics as a tool to discover new antibacterial targets. Biotechnol Lett 2017; 39:819-828. [PMID: 28289911 DOI: 10.1007/s10529-017-2319-0] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2017] [Accepted: 03/07/2017] [Indexed: 12/20/2022]
Abstract
The emergence of antibiotic-resistant pathogens, multiple drug-resistance, and extremely drug-resistant strains demonstrates the need for improved strategies to discover new drug-based compounds. The development of transcriptomics, proteomics, and metabolomics has provided new tools for global studies of living organisms. However, the compendium of expression profiles produced by these methods has introduced new scientific challenges into antimicrobial research. In this review, we discuss the practical value of transcriptomic techniques as well as their difficulties and pitfalls. We advocate the construction of new databases of transcriptomic data, using standardized formats in addition to standardized models of bacterial and yeast similar to those used in systems biology. The inclusion of proteomic and metabolomic data is also essential, as the resulting networks can provide a landscape to rationally predict and exploit new drug targets and to understand drug synergies.
Collapse
Affiliation(s)
- Ángel Domínguez
- Department of Microbiology and Genetics, Universidad de Salamanca, Plaza de los Drs. de la Reina s/n, 37007, Salamanca, Spain.
| | - Elisa Muñoz
- Department of Cell Biology & Pathology, Universidad de Salamanca, Salamanca, Spain
| | - M Carmen López
- Department of Microbiology and Genetics, Universidad de Salamanca, Plaza de los Drs. de la Reina s/n, 37007, Salamanca, Spain
| | - Miguel Cordero
- Department of Medicine, Universidad de Salamanca, Salamanca, Spain
| | - José Pedro Martínez
- Department of Microbiology & Ecology, Universitat de Valencia/Estudi General (UVEG), Valencia, Spain
| | - Miguel Viñas
- Department of Pathology and Experimental Therapeutics, Universitat de Barcelona, Barcelona, Spain
| |
Collapse
|
30
|
Kelliher CM, Haase SB. Connecting virulence pathways to cell-cycle progression in the fungal pathogen Cryptococcus neoformans. Curr Genet 2017; 63:803-811. [PMID: 28265742 PMCID: PMC5605583 DOI: 10.1007/s00294-017-0688-5] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2017] [Revised: 02/22/2017] [Accepted: 02/22/2017] [Indexed: 11/01/2022]
Abstract
Proliferation and host evasion are critical processes to understand at a basic biological level for improving infectious disease treatment options. The human fungal pathogen Cryptococcus neoformans causes fungal meningitis in immunocompromised individuals by proliferating in cerebrospinal fluid. Current antifungal drugs target "virulence factors" for disease, such as components of the cell wall and polysaccharide capsule in C. neoformans. However, mechanistic links between virulence pathways and the cell cycle are not as well studied. Recently, cell-cycle synchronized C. neoformans cells were profiled over time to identify gene expression dynamics (Kelliher et al., PLoS Genet 12(12):e1006453, 2016). Almost 20% of all genes in the C. neoformans genome were periodically activated during the cell cycle in rich media, including 40 genes that have previously been implicated in virulence pathways. Here, we review important findings about cell-cycle-regulated genes in C. neoformans and provide two examples of virulence pathways-chitin synthesis and G-protein coupled receptor signaling-with their putative connections to cell division. We propose that a "comparative functional genomics" approach, leveraging gene expression timing during the cell cycle, orthology to genes in other fungal species, and previous experimental findings, can lead to mechanistic hypotheses connecting the cell cycle to fungal virulence.
Collapse
Affiliation(s)
- Christina M Kelliher
- Department of Biology, Duke University, Box 90338, 130 Science Drive, Durham, NC, 27708-0338, USA
| | - Steven B Haase
- Department of Biology, Duke University, Box 90338, 130 Science Drive, Durham, NC, 27708-0338, USA.
| |
Collapse
|
31
|
Pang CNI, Lai YW, Campbell LT, Chen SCA, Carter DA, Wilkins MR. Transcriptome and network analyses in Saccharomyces cerevisiae reveal that amphotericin B and lactoferrin synergy disrupt metal homeostasis and stress response. Sci Rep 2017; 7:40232. [PMID: 28079179 PMCID: PMC5228129 DOI: 10.1038/srep40232] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2016] [Accepted: 12/02/2016] [Indexed: 12/16/2022] Open
Abstract
Invasive fungal infections are difficult to treat. The few available antifungal drugs have problems with toxicity or efficacy, and resistance is increasing. To overcome these challenges, existing therapies may be enhanced by synergistic combination with another agent. Previously, we found amphotericin B (AMB) and the iron chelator, lactoferrin (LF), were synergistic against a range of different fungal pathogens. This study investigates the mechanism of AMB-LF synergy, using RNA-seq and network analyses. AMB treatment resulted in increased expression of genes involved in iron homeostasis and ATP synthesis. Unexpectedly, AMB-LF treatment did not lead to increased expression of iron and zinc homeostasis genes. However, genes involved in adaptive response to zinc deficiency and oxidative stress had decreased expression. The clustering of co-expressed genes and network analysis revealed that many iron and zinc homeostasis genes are targets of transcription factors Aft1p and Zap1p. The aft1Δ and zap1Δ mutants were hypersensitive to AMB and H2O2, suggesting they are key regulators of the drug response. Mechanistically, AMB-LF synergy could involve AMB affecting the integrity of the cell wall and membrane, permitting LF to disrupt intracellular processes. We suggest that Zap1p- and Aft1p-binding molecules could be combined with existing antifungals to serve as synergistic treatments.
Collapse
Affiliation(s)
- Chi Nam Ignatius Pang
- School of Biotechnology and Biomolecular Sciences, The University of New South Wales, Kensington, New South Wales, Australia
| | - Yu-Wen Lai
- School of Life and Environmental Sciences, University of Sydney, Sydney, New South Wales, Australia
| | - Leona T Campbell
- School of Life and Environmental Sciences, University of Sydney, Sydney, New South Wales, Australia
| | - Sharon C-A Chen
- Marie Bashir Institute for Infectious Diseases and Biosecurity, University of Sydney, Sydney, NSW, Australia.,Centre for Infectious Diseases and Microbiology, Institute of Clinical Pathology and Medical Research, Westmead Hospital, Sydney Medical School, University of Sydney, Westmead, NSW, Australia
| | - Dee A Carter
- School of Life and Environmental Sciences, University of Sydney, Sydney, New South Wales, Australia.,Marie Bashir Institute for Infectious Diseases and Biosecurity, University of Sydney, Sydney, NSW, Australia
| | - Marc R Wilkins
- School of Biotechnology and Biomolecular Sciences, The University of New South Wales, Kensington, New South Wales, Australia
| |
Collapse
|
32
|
Investigating Conservation of the Cell-Cycle-Regulated Transcriptional Program in the Fungal Pathogen, Cryptococcus neoformans. PLoS Genet 2016; 12:e1006453. [PMID: 27918582 PMCID: PMC5137879 DOI: 10.1371/journal.pgen.1006453] [Citation(s) in RCA: 35] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2016] [Accepted: 11/01/2016] [Indexed: 12/24/2022] Open
Abstract
The pathogenic yeast Cryptococcus neoformans causes fungal meningitis in immune-compromised patients. Cell proliferation in the budding yeast form is required for C. neoformans to infect human hosts, and virulence factors such as capsule formation and melanin production are affected by cell-cycle perturbation. Thus, understanding cell-cycle regulation is critical for a full understanding of virulence factors for disease. Our group and others have demonstrated that a large fraction of genes in Saccharomyces cerevisiae is expressed periodically during the cell cycle, and that proper regulation of this transcriptional program is important for proper cell division. Despite the evolutionary divergence of the two budding yeasts, we found that a similar percentage of all genes (~20%) is periodically expressed during the cell cycle in both yeasts. However, the temporal ordering of periodic expression has diverged for some orthologous cell-cycle genes, especially those related to bud emergence and bud growth. Genes regulating DNA replication and mitosis exhibited a conserved ordering in both yeasts, suggesting that essential cell-cycle processes are conserved in periodicity and in timing of expression (i.e. duplication before division). In S. cerevisiae cells, we have proposed that an interconnected network of periodic transcription factors (TFs) controls the bulk of the cell-cycle transcriptional program. We found that temporal ordering of orthologous network TFs was not always maintained; however, the TF network topology at cell-cycle commitment appears to be conserved in C. neoformans. During the C. neoformans cell cycle, DNA replication genes, mitosis genes, and 40 genes involved in virulence are periodically expressed. Future work toward understanding the gene regulatory network that controls cell-cycle genes is critical for developing novel antifungals to inhibit pathogen proliferation.
Collapse
|
33
|
Bultman KM, Kowalski CH, Cramer RA. Aspergillus fumigatus virulence through the lens of transcription factors. Med Mycol 2016; 55:24-38. [PMID: 27816905 DOI: 10.1093/mmy/myw120] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2016] [Revised: 08/19/2016] [Accepted: 10/17/2016] [Indexed: 02/07/2023] Open
Abstract
Invasive aspergillosis (IA), most commonly caused by the filamentous fungus Aspergillus fumigatus, occurs in immune compromised individuals. The ability of A. fumigatus to proliferate in a multitude of environments is hypothesized to contribute to its pathogenicity and virulence. Transcription factors (TF) have long been recognized as critical proteins for fungal pathogenicity, as many are known to play important roles in the transcriptional regulation of pathways implicated in virulence. Such pathways include regulation of conidiation and development, adhesion, nutrient acquisition, adaptation to environmental stress, and interactions with the host immune system among others. In both murine and insect models of IA, TF loss of function in A. fumigatus results in cases of hyper- and hypovirulence as determined through host survival, fungal burden, and immune response analyses. Consequently, the study of specific TFs in A. fumigatus has revealed important insights into mechanisms of pathogenicity and virulence. Although in vitro studies have identified virulence-related functions of specific TFs, the full picture of their in vivo functions remain largely enigmatic and an exciting area of current research. Moreover, the vast majority of TFs remain to be characterized and studied in this important human pathogen. Here in this mini-review we provide an overview of selected TFs in A. fumigatus and their contribution to our understanding of this important human pathogen's pathogenicity and virulence.
Collapse
Affiliation(s)
- Katherine M Bultman
- Department of Microbiology and Immunology, Geisel School of Medicine at Dartmouth, Hanover, NH 03755
| | - Caitlin H Kowalski
- Department of Microbiology and Immunology, Geisel School of Medicine at Dartmouth, Hanover, NH 03755
| | - Robert A Cramer
- Department of Microbiology and Immunology, Geisel School of Medicine at Dartmouth, Hanover, NH 03755
| |
Collapse
|
34
|
Ding H, Mayer FL, Sánchez-León E, de S Araújo GR, Frases S, Kronstad JW. Networks of fibers and factors: regulation of capsule formation in Cryptococcus neoformans. F1000Res 2016; 5. [PMID: 27516877 PMCID: PMC4979528 DOI: 10.12688/f1000research.8854.1] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 07/12/2016] [Indexed: 12/15/2022] Open
Abstract
The ability of the pathogenic fungus
Cryptococcus neoformans to cause life-threatening meningoencephalitis in immunocompromised individuals is due in large part to elaboration of a capsule consisting of polysaccharide fibers. The size of the cell-associated capsule is remarkably responsive to a variety of environmental and host conditions, but the mechanistic details of the regulation, synthesis, trafficking, and attachment of the polysaccharides are poorly understood. Recent studies reveal a complex network of transcription factors that influence capsule elaboration in response to several different signals of relevance to disease (e.g., iron deprivation). The emerging complexity of the network is consistent with the diversity of conditions that influence the capsule and illustrates the responsiveness of the fungus to both the environment and mammalian hosts.
Collapse
Affiliation(s)
- Hao Ding
- Michael Smith Laboratories, University of British Columbia, Vancouver, Canada
| | - François L Mayer
- Michael Smith Laboratories, University of British Columbia, Vancouver, Canada
| | - Eddy Sánchez-León
- Michael Smith Laboratories, University of British Columbia, Vancouver, Canada
| | - Glauber R de S Araújo
- Laboratório de Ultraestrutura Celular Hertha Meyer, Instituto de Biofísica Carlos Chagas Filho, Federal University of Rio de Janeiro, Rio de Janeiro, Brazil
| | - Susana Frases
- Laboratório de Ultraestrutura Celular Hertha Meyer, Instituto de Biofísica Carlos Chagas Filho, Federal University of Rio de Janeiro, Rio de Janeiro, Brazil
| | - James W Kronstad
- Michael Smith Laboratories, University of British Columbia, Vancouver, Canada.,Department of Microbiology and Immunology, University of British Columbia, Vancouver, Canada
| |
Collapse
|
35
|
Gsaller F, Hortschansky P, Furukawa T, Carr PD, Rash B, Capilla J, Müller C, Bracher F, Bowyer P, Haas H, Brakhage AA, Bromley MJ. Sterol Biosynthesis and Azole Tolerance Is Governed by the Opposing Actions of SrbA and the CCAAT Binding Complex. PLoS Pathog 2016; 12:e1005775. [PMID: 27438727 PMCID: PMC4954732 DOI: 10.1371/journal.ppat.1005775] [Citation(s) in RCA: 80] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2016] [Accepted: 06/28/2016] [Indexed: 02/01/2023] Open
Abstract
Azole drugs selectively target fungal sterol biosynthesis and are critical to our antifungal therapeutic arsenal. However, resistance to this class of drugs, particularly in the major human mould pathogen Aspergillus fumigatus, is emerging and reaching levels that have prompted some to suggest that there is a realistic probability that they will be lost for clinical use. The dominating class of pan-azole resistant isolates is characterized by the presence of a tandem repeat of at least 34 bases (TR34) within the promoter of cyp51A, the gene encoding the azole drug target sterol C14-demethylase. Here we demonstrate that the repeat sequence in TR34 is bound by both the sterol regulatory element binding protein (SREBP) SrbA, and the CCAAT binding complex (CBC). We show that the CBC acts complementary to SrbA as a negative regulator of ergosterol biosynthesis and show that lack of CBC activity results in increased sterol levels via transcriptional derepression of multiple ergosterol biosynthetic genes including those coding for HMG-CoA-synthase, HMG-CoA-reductase and sterol C14-demethylase. In agreement with these findings, inactivation of the CBC increased tolerance to different classes of drugs targeting ergosterol biosynthesis including the azoles, allylamines (terbinafine) and statins (simvastatin). We reveal that a clinically relevant mutation in HapE (P88L) significantly impairs the binding affinity of the CBC to its target site. We identify that the mechanism underpinning TR34 driven overexpression of cyp51A results from duplication of SrbA but not CBC binding sites and show that deletion of the 34 mer results in lack of cyp51A expression and increased azole susceptibility similar to a cyp51A null mutant. Finally we show that strains lacking a functional CBC are severely attenuated for pathogenicity in a pulmonary and systemic model of aspergillosis. Aspergillus fumigatus is the most important airborne mould pathogen and allergen worldwide. Estimates suggest that >3 million people have invasive or chronic infections that lead to >600,000 deaths every year. Very few drugs are available to treat the various forms of aspergillosis and we rely predominantly on the azole class of agents which inhibit sterol biosynthesis. Resistance to the azoles is growing alarmingly, primarily driven by strains with two principal genetic signatures (TR34/L98H and TR46/Y121F/T289A). In this study we identify that the transcriptional mechanism governing resistance in this group of isolates is linked to the opposing actions of 2 transcriptional regulators, SrbA and the CBC, and uncover a role for the CBC in sterol regulation and virulence in A. fumigatus. We propose targeting SrbA would provide an effective avenue for therapeutic intervention for resistant strains.
Collapse
Affiliation(s)
- Fabio Gsaller
- Manchester Fungal Infection Group, Institute of Inflammation and Repair, University of Manchester, Manchester, United Kingdom
| | - Peter Hortschansky
- Department of Molecular and Applied Microbiology, Leibniz Institute for Natural Product Research and Infection Biology (HKI), Jena, Germany
| | - Takanori Furukawa
- Manchester Fungal Infection Group, Institute of Inflammation and Repair, University of Manchester, Manchester, United Kingdom
| | - Paul D. Carr
- Manchester Fungal Infection Group, Institute of Inflammation and Repair, University of Manchester, Manchester, United Kingdom
| | - Bharat Rash
- Manchester Fungal Infection Group, Institute of Inflammation and Repair, University of Manchester, Manchester, United Kingdom
| | - Javier Capilla
- Microbiology Unit, Medical School, Universitat Rovira i Virgili, Reus, Spain
| | - Christoph Müller
- Department of Pharmacy, Center for Drug Research, Ludwig-Maximilians University of Munich, Munich, Germany
| | - Franz Bracher
- Department of Pharmacy, Center for Drug Research, Ludwig-Maximilians University of Munich, Munich, Germany
| | - Paul Bowyer
- Manchester Fungal Infection Group, Institute of Inflammation and Repair, University of Manchester, Manchester, United Kingdom
| | - Hubertus Haas
- Division of Molecular Biology, Biocentre, Medical University of Innsbruck, Innsbruck, Austria
| | - Axel A. Brakhage
- Department of Molecular and Applied Microbiology, Leibniz Institute for Natural Product Research and Infection Biology (HKI), Jena, Germany
- Institute for Microbiology, Friedrich Schiller University Jena, Jena, Germany
| | - Michael J. Bromley
- Manchester Fungal Infection Group, Institute of Inflammation and Repair, University of Manchester, Manchester, United Kingdom
- * E-mail:
| |
Collapse
|