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Kim MJ, Cravener M, Solis N, Filler SG, Mitchell AP. A Brg1-Rme1 circuit in Candida albicans hyphal gene regulation. mBio 2024; 15:e0187224. [PMID: 39078139 PMCID: PMC11389389 DOI: 10.1128/mbio.01872-24] [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: 06/18/2024] [Accepted: 06/28/2024] [Indexed: 07/31/2024] Open
Abstract
Major Candida albicans virulence traits include its ability to make hyphae, to produce a biofilm, and to damage host cells. These traits depend upon expression of hypha-associated genes. A gene expression comparison among clinical isolates suggested that transcription factor Rme1, established by previous studies to be a positive regulator of chlamydospore formation, may also be a negative regulator of hypha-associated genes. Engineered RME1 overexpression supported this hypothesis, but no relevant rme1Δ/Δ mutant phenotype was detected. We reasoned that Rme1 may function within a specific regulatory pathway. This idea was supported by our finding that an rme1Δ/Δ mutation relieves the need for biofilm regulator Brg1 in biofilm formation. The impact of the rme1Δ/Δ mutation is most prominent under static or "biofilm-like" growth conditions. RNA sequencing (RNA-seq) of cells grown under biofilm-like conditions indicates that Brg1 activates hypha-associated genes indirectly via repression of RME1: hypha-associated gene expression levels are substantially reduced in a brg1Δ/Δ mutant and partially restored in a brg1Δ/Δ rme1Δ/Δ double mutant. An rme1Δ/Δ mutation does not simply bypass Brg1, because iron homeostasis genes depend upon Brg1 regardless of Rme1. Rme1 thus connects Brg1 to the targets relevant to hypha and biofilm formation under biofilm growth conditions.IMPORTANCECandida albicans is a major fungal pathogen of humans, and its ability to grow as a surface-associated biofilm on implanted devices is a common cause of infection. Here, we describe a new regulator of biofilm formation, RME1, whose activity is most prominent under biofilm-like growth conditions.
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Affiliation(s)
- Min-Ju Kim
- Department of Microbiology, University of Georgia, Athens, Georgia, USA
| | - Max Cravener
- Department of Microbiology, University of Georgia, Athens, Georgia, USA
| | - Norma Solis
- Lundquist Institute for Biomedical Innovation at Harbor-UCLA Medical Center, Torrance, California, USA
| | - Scott G Filler
- Lundquist Institute for Biomedical Innovation at Harbor-UCLA Medical Center, Torrance, California, USA
- David Geffen School of Medicine at UCLA, Los Angeles, California, USA
| | - Aaron P Mitchell
- Department of Microbiology, University of Georgia, Athens, Georgia, USA
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Vandermeulen MD, Lorenz MC, Cullen PJ. Conserved signaling modules regulate filamentous growth in fungi: a model for eukaryotic cell differentiation. Genetics 2024:iyae122. [PMID: 39239926 DOI: 10.1093/genetics/iyae122] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2024] [Accepted: 07/20/2024] [Indexed: 09/07/2024] Open
Abstract
Eukaryotic organisms are composed of different cell types with defined shapes and functions. Specific cell types are produced by the process of cell differentiation, which is regulated by signal transduction pathways. Signaling pathways regulate cell differentiation by sensing cues and controlling the expression of target genes whose products generate cell types with specific attributes. In studying how cells differentiate, fungi have proved valuable models because of their ease of genetic manipulation and striking cell morphologies. Many fungal species undergo filamentous growth-a specialized growth pattern where cells produce elongated tube-like projections. Filamentous growth promotes expansion into new environments, including invasion into plant and animal hosts by fungal pathogens. The same signaling pathways that regulate filamentous growth in fungi also control cell differentiation throughout eukaryotes and include highly conserved mitogen-activated protein kinase (MAPK) pathways, which is the focus of this review. In many fungal species, mucin-type sensors regulate MAPK pathways to control filamentous growth in response to diverse stimuli. Once activated, MAPK pathways reorganize cell polarity, induce changes in cell adhesion, and promote the secretion of degradative enzymes that mediate access to new environments. However, MAPK pathway regulation is complicated because related pathways can share components with each other yet induce unique responses (i.e. signal specificity). In addition, MAPK pathways function in highly integrated networks with other regulatory pathways (i.e. signal integration). Here, we discuss signal specificity and integration in several yeast models (mainly Saccharomyces cerevisiae and Candida albicans) by focusing on the filamentation MAPK pathway. Because of the strong evolutionary ties between species, a deeper understanding of the regulation of filamentous growth in established models and increasingly diverse fungal species can reveal fundamentally new mechanisms underlying eukaryotic cell differentiation.
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Affiliation(s)
| | - Michael C Lorenz
- Department of Microbiology and Molecular Genetics, University of Texas McGovern Medical School, Houston, TX 77030, USA
| | - Paul J Cullen
- Department of Biological Sciences, University at Buffalo, Buffalo, NY 14260-1300, USA
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3
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Murante D, Hogan DA. Drivers of diversification in fungal pathogen populations. PLoS Pathog 2024; 20:e1012430. [PMID: 39264909 PMCID: PMC11392411 DOI: 10.1371/journal.ppat.1012430] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 09/14/2024] Open
Abstract
To manage and treat chronic fungal diseases effectively, we require an improved understanding of their complexity. There is an increasing appreciation that chronic infection populations are often heterogeneous due to diversification and drift, even within a single microbial species. Genetically diverse populations can contribute to persistence and resistance to treatment by maintaining cells with different phenotypes capable of thriving in these dynamic environments. In chronic infections, fungal pathogens undergo prolonged challenges that can drive trait selection to convergent adapted states through restricted access to critical nutrients, assault by immune effectors, competition with other species, and antifungal drugs. This review first highlights the various genetic and epigenetic mechanisms that promote diversity in pathogenic fungal populations and provide an additional barrier to assessing the actual heterogeneity of fungal infections. We then review existing studies of evolution and genetic heterogeneity in fungal populations from lung infections associated with the genetic disease cystic fibrosis. We conclude with a discussion of open research questions that, once answered, may aid in diagnosing and treating chronic fungal infections.
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Affiliation(s)
- Daniel Murante
- Department of Microbiology and Immunology, Geisel School of Medicine at Dartmouth, Hanover, New Hampshire, United States of America
| | - Deborah Ann Hogan
- Department of Microbiology and Immunology, Geisel School of Medicine at Dartmouth, Hanover, New Hampshire, United States of America
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Gavandi T, Patil S, Basrani S, Yankanchi S, Chougule S, Karuppayil SM, Jadhav A. MIG1, TUP1 and NRG1 mediated yeast to hyphal morphogenesis inhibition in Candida albicans by ganciclovir. Braz J Microbiol 2024; 55:2047-2056. [PMID: 38789908 PMCID: PMC11405576 DOI: 10.1007/s42770-024-01344-8] [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: 11/06/2023] [Accepted: 04/09/2024] [Indexed: 05/26/2024] Open
Abstract
Candida albicans is a polymorphic human fungal pathogen and the prime etiological agent responsible for candidiasis. The main two aspects of C. albicans virulence that have been suggested are yeast-to-hyphal (Y-H) morphological transitions and biofilm development. Anti-fungal agents targeting these virulence attributes enhances the antifungal drug development process. Repositioning with other non-fungal drugs offered a one of the new strategies and a potential alternative option to counter the urgent need for antifungal drug development. In the current study, an antiviral drug ganciclovir was screened as an antifungal agent against ATCC 90028, 10231 and clinical isolate (C1). Ganciclovir at 0.5 mg/ml concentration reduced 50% hyphal development on a silicon-based urinary catheter and was visualized using scanning electron microscopy. Ganciclovir reduced ergosterol biosynthesis in both strains and C1 isolate of C. albicans in a concentration-dependent manner. Additionally, a gene expression profile study showed that ganciclovir treatment resulted in upregulation of hyphal-specific repressors MIG1, TUP1, and NRG1 in C. albicans. Additionally, an in vivo study on the Bombyx mori silkworm model further evidenced the virulence inhibitory ability of ganciclovir (0.5 mg/ml) against C. albicans. This is the first report that explore the novel anti-morphogenic activities of ganciclovir against the pathogenic C. albicans strains, along with clinical isolates. Further, ganciclovir may be considered for therapeutic purpose after combinations with standard antifungal agents.
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Affiliation(s)
- Tanjila Gavandi
- Department of Stem cell and Regenerative Medicine, Medical Biotechnology, Centre for Interdisciplinary Research, D. Y. Patil Education Society (Deemed to be University), 416006, Kolhapur, Maharashtra, India
| | - Shivani Patil
- Department of Stem cell and Regenerative Medicine, Medical Biotechnology, Centre for Interdisciplinary Research, D. Y. Patil Education Society (Deemed to be University), 416006, Kolhapur, Maharashtra, India
| | - Sargun Basrani
- Department of Stem cell and Regenerative Medicine, Medical Biotechnology, Centre for Interdisciplinary Research, D. Y. Patil Education Society (Deemed to be University), 416006, Kolhapur, Maharashtra, India
| | - Shivanand Yankanchi
- Department of Zoology, Shivaji University, Vidya Nagar, 416004, Kolhapur, Maharashtra, India
| | - Sayali Chougule
- Department of Stem cell and Regenerative Medicine, Medical Biotechnology, Centre for Interdisciplinary Research, D. Y. Patil Education Society (Deemed to be University), 416006, Kolhapur, Maharashtra, India
| | - S Mohan Karuppayil
- Department of Stem cell and Regenerative Medicine, Medical Biotechnology, Centre for Interdisciplinary Research, D. Y. Patil Education Society (Deemed to be University), 416006, Kolhapur, Maharashtra, India.
| | - Ashwini Jadhav
- Department of Stem cell and Regenerative Medicine, Medical Biotechnology, Centre for Interdisciplinary Research, D. Y. Patil Education Society (Deemed to be University), 416006, Kolhapur, Maharashtra, India.
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5
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Cao X, Xiao N, Huang J, Li L, Zhong L, Zhang J, Wang F. Synergistic in vitro activity and mechanism of KBN lotion and miconazole nitrate against drug-resistant Candida albicans biofilms. Front Cell Infect Microbiol 2024; 14:1426791. [PMID: 39268490 PMCID: PMC11390680 DOI: 10.3389/fcimb.2024.1426791] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2024] [Accepted: 07/31/2024] [Indexed: 09/15/2024] Open
Abstract
Background In the face of increasing antifungal resistance among Candida albicans biofilms, this study explores the efficacy of a combined treatment using Kangbainian lotion (KBN) and miconazole nitrate (MN) to address this challenge. Methods Using UPLC-Q-TOF/MS Analysis for Identification of Active Compounds in KBN Lotion; FICI for synergy evaluation, XTT and ROS assays for biofilm viability and oxidative stress, fluorescence and confocal laser scanning microscopy (CLSM) for structural and viability analysis, and real-time fluorescence for gene expression. Conclusion Our study indicates that the combined application of KBN and MN somewhat impacts the structural integrity of Candida albicans biofilms and affects the expression of several key genes involved in biofilm formation, including ALS1, ALS3, HWP1, HSP90, and CSH1. These preliminary findings suggest that there may be a synergistic effect between KBN and MN, potentially influencing not only the structural aspects of fungal biofilms but also involving the modulation of genetic pathways during their formation.
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Affiliation(s)
- Xiaoyu Cao
- School of Traditional Chinese Medicine, Guangdong Pharmaceutical University, Guangzhou, China
| | - Ni Xiao
- School of Pharmaceutical Sciences, Guangzhou University of Chinese Medicine, Guangzhou, China
| | - Jingyi Huang
- School of Traditional Chinese Medicine, Guangdong Pharmaceutical University, Guangzhou, China
| | - Li Li
- School of Pharmaceutical Sciences, Guangzhou University of Chinese Medicine, Guangzhou, China
| | - Lian Zhong
- School of Pharmaceutical Sciences, Guangzhou University of Chinese Medicine, Guangzhou, China
| | - Jun Zhang
- School of Pharmaceutical Sciences, Guangzhou University of Chinese Medicine, Guangzhou, China
| | - Fengyun Wang
- School of Traditional Chinese Medicine, Guangdong Pharmaceutical University, Guangzhou, China
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Utkalaja BG, Patel SK, Sahu SR, Dutta A, Acharya N. Critical roles of Dpb3-Dpb4 sub-complex of DNA polymerase epsilon in DNA replication, genome stability, and pathogenesis of Candida albicans. mBio 2024:e0122724. [PMID: 39207097 DOI: 10.1128/mbio.01227-24] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2024] [Accepted: 08/07/2024] [Indexed: 09/04/2024] Open
Abstract
DNA polymerase ε (Polε) is an essential replicative polymerase consisting of Pol2, Dpb2, Dpb3, and Dpb4 subunits and has not been explored in the pathogenic yeast Candida albicans. C. albicans is accountable for >40% of deaths due to systemic candidiasis per year worldwide. Genome plasticity is one of the adaptive mechanisms associated with virulence, and as it is associated with DNA polymerase function, this study explored the role of Polε in genome stability and pathogenesis of C. albicans. POL2 and DPB2 are haploinsufficient, but DPB3 and DPB4 are dispensable for cell survival in diploid C. albicans. However, unlike in Saccharomyces cerevisiae, loss of any or both of the nonessential subunits or defective interaction between the two resulted in slow growth and temperature-sensitive phenotypes. Knockout strains of C. albicans (dpb3ΔΔ and dpb4ΔΔ and dpb3ΔΔdpb4ΔΔ) also exhibited sensitivity to genotoxic agents and delayed cell cycle progression. Reduced processive DNA synthesis and increased rate of mutagenesis were observed in dpb3 and dpb4 null strains. Whole-genome sequencing further confirmed the accumulation of indels and SNPs majorly in the intergenic repeat regions of the chromosomes of dpb3ΔΔdpb4ΔΔ. Polε-defective strains were constitutively filamentous and non-pathogenic in mice models of systemic candidiasis. Altogether, this study showed that the function of the Dpb3-Dpb4 subcomplex is critical for fungal morphogenesis and virulence besides its role as a structural component of Polε in DNA replication and genome stability; thus, their interacting interface may be targeted to develop antifungal drugs. IMPORTANCE This study explored the role of DNA polymerase epsilon, especially its non-essential structural subunits in Candida albicans biology. Apart from their role in DNA replication and genome stability, the Dpb3-Dpb4 subcomplex regulates morphological switching and virulence. Since the defective strain is locked in filamentous form and is avirulent, the complex may be targeted for anti-fungal drug development.
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Affiliation(s)
- Bhabasha Gyanadeep Utkalaja
- Laboratory of Genomic Instability and Diseases, Department of Infectious Disease Biology, Institute of Life Sciences, Bhubaneswar, India
- Regional Center of Biotechnology, Faridabad, India
| | - Shraddheya Kumar Patel
- Laboratory of Genomic Instability and Diseases, Department of Infectious Disease Biology, Institute of Life Sciences, Bhubaneswar, India
- Regional Center of Biotechnology, Faridabad, India
| | - Satya Ranjan Sahu
- Laboratory of Genomic Instability and Diseases, Department of Infectious Disease Biology, Institute of Life Sciences, Bhubaneswar, India
- Regional Center of Biotechnology, Faridabad, India
| | - Abinash Dutta
- Laboratory of Genomic Instability and Diseases, Department of Infectious Disease Biology, Institute of Life Sciences, Bhubaneswar, India
| | - Narottam Acharya
- Laboratory of Genomic Instability and Diseases, Department of Infectious Disease Biology, Institute of Life Sciences, Bhubaneswar, India
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7
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Kramara J, Kim MJ, Ollinger TL, Ristow LC, Wakade RS, Zarnowski R, Wellington M, Andes DR, Mitchell AG, Krysan DJ. Systematic analysis of the Candida albicans kinome reveals environmentally contingent protein kinase-mediated regulation of filamentation and biofilm formation in vitro and in vivo. mBio 2024; 15:e0124924. [PMID: 38949302 PMCID: PMC11323567 DOI: 10.1128/mbio.01249-24] [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: 04/25/2024] [Accepted: 05/20/2024] [Indexed: 07/02/2024] Open
Abstract
Protein kinases are critical regulatory proteins in both prokaryotes and eukaryotes. Accordingly, protein kinases represent a common drug target for a wide range of human diseases. Therefore, understanding protein kinase function in human pathogens such as the fungus Candida albicans is likely to extend our knowledge of its pathobiology and identify new potential therapies. To facilitate the study of C. albicans protein kinases, we constructed a library of 99 non-essential protein kinase homozygous deletion mutants marked with barcodes in the widely used SN genetic background. Here, we describe the construction of this library and the characterization of the competitive fitness of the protein kinase mutants under 11 different growth and stress conditions. We also screened the library for protein kinase mutants with altered filamentation and biofilm formation, two critical virulence traits of C. albicans. An extensive network of protein kinases governs these virulence traits in a manner highly dependent on the specific environmental conditions. Studies on specific protein kinases revealed that (i) the cell wall integrity MAPK pathway plays a condition-dependent role in filament initiation and elongation; (ii) the hyper-osmolar glycerol MAPK pathway is required for both filamentation and biofilm formation, particularly in the setting of in vivo catheter infection; and (iii) Sok1 is dispensable for filamentation in hypoxic environments at the basal level of a biofilm but is required for filamentation in normoxia. In addition to providing a new genetic resource for the community, these observations emphasize the environmentally contingent function of C. albicans protein kinases.IMPORTANCECandida albicans is one of the most common causes of fungal disease in humans for which new therapies are needed. Protein kinases are key regulatory proteins and are increasingly targeted by drugs for the treatment of a wide range of diseases. Understanding protein kinase function in C. albicans pathogenesis may facilitate the development of new antifungal drugs. Here, we describe a new library of 99 protein kinase deletion mutants to facilitate the study of protein kinases. Furthermore, we show that the function of protein kinases in two virulence-related processes, filamentation and biofilm formation, is dependent on the specific environmental conditions.
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Affiliation(s)
- Juraj Kramara
- Department of Pediatrics, Carver College of Medicine, University of Iowa, Iowa City, Iowa, USA
| | - Min-Ju Kim
- Department of Microbiology, University of Georgia, Athens, Georgia, USA
| | - Tomye L. Ollinger
- Department of Pediatrics, Carver College of Medicine, University of Iowa, Iowa City, Iowa, USA
| | - Laura C. Ristow
- Department of Pediatrics, Carver College of Medicine, University of Iowa, Iowa City, Iowa, USA
| | - Rohan S. Wakade
- Department of Pediatrics, Carver College of Medicine, University of Iowa, Iowa City, Iowa, USA
| | - Robert Zarnowski
- Department of Medicine, Section of Infectious Disease, University of Wisconsin, Madison, Wisconsin, USA
- Department of Medical Microbiology and Immunology, University of Wisconsin, Madison, Wisconsin, USA
| | - Melanie Wellington
- Department of Pediatrics, Carver College of Medicine, University of Iowa, Iowa City, Iowa, USA
| | - David R. Andes
- Department of Medicine, Section of Infectious Disease, University of Wisconsin, Madison, Wisconsin, USA
- Department of Medical Microbiology and Immunology, University of Wisconsin, Madison, Wisconsin, USA
| | - Aaron G. Mitchell
- Department of Microbiology, University of Georgia, Athens, Georgia, USA
| | - Damian J. Krysan
- Department of Pediatrics, Carver College of Medicine, University of Iowa, Iowa City, Iowa, USA
- Department of Molecular Physiology and Biophysics, Carver College of Medicine, University of Iowa, Iowa City, Iowa, USA
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Acs-Szabo L, Papp LA, Miklos I. Understanding the molecular mechanisms of human diseases: the benefits of fission yeasts. MICROBIAL CELL (GRAZ, AUSTRIA) 2024; 11:288-311. [PMID: 39104724 PMCID: PMC11299203 DOI: 10.15698/mic2024.08.833] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Received: 03/06/2024] [Revised: 07/04/2024] [Accepted: 07/10/2024] [Indexed: 08/07/2024]
Abstract
The role of model organisms such as yeasts in life science research is crucial. Although the baker's yeast (Saccharomyces cerevisiae) is the most popular model among yeasts, the contribution of the fission yeasts (Schizosaccharomyces) to life science is also indisputable. Since both types of yeasts share several thousands of common orthologous genes with humans, they provide a simple research platform to investigate many fundamental molecular mechanisms and functions, thereby contributing to the understanding of the background of human diseases. In this review, we would like to highlight the many advantages of fission yeasts over budding yeasts. The usefulness of fission yeasts in virus research is shown as an example, presenting the most important research results related to the Human Immunodeficiency Virus Type 1 (HIV-1) Vpr protein. Besides, the potential role of fission yeasts in the study of prion biology is also discussed. Furthermore, we are keen to promote the uprising model yeast Schizosaccharomyces japonicus, which is a dimorphic species in the fission yeast genus. We propose the hyphal growth of S. japonicus as an unusual opportunity as a model to study the invadopodia of human cancer cells since the two seemingly different cell types can be compared along fundamental features. Here we also collect the latest laboratory protocols and bioinformatics tools for the fission yeasts to highlight the many possibilities available to the research community. In addition, we present several limiting factors that everyone should be aware of when working with yeast models.
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Affiliation(s)
- Lajos Acs-Szabo
- Department of Genetics and Applied Microbiology, Faculty of Science and Technology, University of DebrecenDebrecen, 4032Hungary
| | - Laszlo Attila Papp
- Department of Genetics and Applied Microbiology, Faculty of Science and Technology, University of DebrecenDebrecen, 4032Hungary
| | - Ida Miklos
- Department of Genetics and Applied Microbiology, Faculty of Science and Technology, University of DebrecenDebrecen, 4032Hungary
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Komath SS. To each its own: Mechanisms of cross-talk between GPI biosynthesis and cAMP-PKA signaling in Candida albicans versus Saccharomyces cerevisiae. J Biol Chem 2024; 300:107444. [PMID: 38838772 PMCID: PMC11294708 DOI: 10.1016/j.jbc.2024.107444] [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: 03/19/2024] [Revised: 05/24/2024] [Accepted: 05/29/2024] [Indexed: 06/07/2024] Open
Abstract
Candida albicans is an opportunistic fungal pathogen that can switch between yeast and hyphal morphologies depending on the environmental cues it receives. The switch to hyphal form is crucial for the establishment of invasive infections. The hyphal form is also characterized by the cell surface expression of hyphae-specific proteins, many of which are GPI-anchored and important determinants of its virulence. The coordination between hyphal morphogenesis and the expression of GPI-anchored proteins is made possible by an interesting cross-talk between GPI biosynthesis and the cAMP-PKA signaling cascade in the fungus; a parallel interaction is not found in its human host. On the other hand, in the nonpathogenic yeast, Saccharomyces cerevisiae, GPI biosynthesis is shut down when filamentation is activated and vice versa. This too is achieved by a cross-talk between GPI biosynthesis and cAMP-PKA signaling. How are diametrically opposite effects obtained from the cross-talk between two reasonably well-conserved pathways present ubiquitously across eukarya? This Review attempts to provide a model to explain these differences. In order to do so, it first provides an overview of the two pathways for the interested reader, highlighting the similarities and differences that are observed in C. albicans versus the well-studied S. cerevisiae model, before going on to explain how the different mechanisms of regulation are effected. While commonalities enable the development of generalized theories, it is hoped that a more nuanced approach, that takes into consideration species-specific differences, will enable organism-specific understanding of these processes and contribute to the development of targeted therapies.
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Firdous Z, Kalra S, Chattopadhyay R, Bari VK. Current insight into the role of mRNA decay pathways in fungal pathogenesis. Microbiol Res 2024; 283:127671. [PMID: 38479232 DOI: 10.1016/j.micres.2024.127671] [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: 12/18/2023] [Revised: 02/19/2024] [Accepted: 02/29/2024] [Indexed: 04/17/2024]
Abstract
Pathogenic fungal species can cause superficial and mucosal infections, to potentially fatal systemic or invasive infections in humans. These infections are more common in immunocompromised or critically ill patients and have a significant morbidity and fatality rate. Fungal pathogens utilize several strategies to adapt the host environment resulting in efficient and comprehensive alterations in their cellular metabolism. Fungal virulence is regulated by several factors and post-transcriptional regulation mechanisms involving mRNA molecules are one of them. Post-transcriptional controls have emerged as critical regulatory mechanisms involved in the pathogenesis of fungal species. The untranslated upstream and downstream regions of the mRNA, as well as RNA-binding proteins, regulate morphogenesis and virulence by controlling mRNA degradation and stability. The limited number of available therapeutic drugs, the emergence of multidrug resistance, and high death rates associated with systemic fungal illnesses pose a serious risk to human health. Therefore, new antifungal treatments that specifically target mRNA pathway components can decrease fungal pathogenicity and when combined increase the effectiveness of currently available antifungal drugs. This review summarizes the mRNA degradation pathways and their role in fungal pathogenesis.
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Affiliation(s)
- Zulikha Firdous
- Department of Biochemistry, School of Basic Sciences, Central University of Punjab, VPO-Ghudda, Bathinda 151401, India
| | - Sapna Kalra
- Department of Biochemistry, School of Basic Sciences, Central University of Punjab, VPO-Ghudda, Bathinda 151401, India
| | - Rituja Chattopadhyay
- Department of Biochemistry, School of Basic Sciences, Central University of Punjab, VPO-Ghudda, Bathinda 151401, India
| | - Vinay Kumar Bari
- Department of Biochemistry, School of Basic Sciences, Central University of Punjab, VPO-Ghudda, Bathinda 151401, India.
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Wakade RS, Wellington M, Krysan DJ. Temporal dynamics of Candida albicans morphogenesis and gene expression reveals distinctions between in vitro and in vivo filamentation. mSphere 2024; 9:e0011024. [PMID: 38501830 PMCID: PMC11036811 DOI: 10.1128/msphere.00110-24] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2024] [Accepted: 02/29/2024] [Indexed: 03/20/2024] Open
Abstract
Candida albicans is a common human fungal pathogen that is also a commensal of the oral cavity and gastrointestinal tract. C. albicans pathogenesis is linked to its transition from budding yeast to filamentous morphologies including hyphae and pseudohyphae. The centrality of this virulence trait to C. albicans pathobiology has resulted in extensive characterization of a wide range of factors associated with filamentation with a strong focus on transcriptional regulation. The vast majority of these experiments have used in vitro conditions to induce the yeast-to-filament transition. Taking advantage of in vivo approaches to quantitatively characterize both morphology and gene expression during filamentation during mammalian infection, we have investigated the dynamics of these two aspects of filamentation in vivo and compared them to in vitro filament induction with "host-like" tissue culture media supplemented with serum at mammalian body temperature. Although filamentation shares many common features in the two conditions, we have found two significant differences. First, alternative carbon metabolism genes are expressed early during in vitro filamentation and late in vivo, suggesting significant differences in glucose availability. Second, C. albicans begins a hyphae-to-yeast transition after 4-h incubation while we find little evidence of hyphae-to-yeast transition in vivo up to 24 h post-infection. We show that the low rate of in vivo hyphae-to-yeast transition is likely due to the very low expression of PES1, a key driver of lateral yeast in vitro and that heterologous expression of PES1 is sufficient to trigger lateral yeast formation in vivo.IMPORTANCECandida albicans filamentation is correlated with virulence and is an intensively studied aspect of C. albicans biology. The vast majority of studies on C. albicans filamentation are based on in vitro induction of hyphae and pseudohyphae. Here we used an in vivo filamentation assay and in vivo expression profiling to compare the tempo of morphogenesis and gene expression between in vitro and in vivo filamentation. Although the hyphal gene expression profile is induced rapidly in both conditions, it remains stably expressed over a 12-h time course in vivo while it peaks after 4 h in vitro and is reduced. This reduced hyphal gene expression in vitro correlates with reduced hyphae and increased hyphae-to-yeast transition. By contrast, there is little evidence of hyphae-to-yeast transition in vivo.
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Affiliation(s)
- Rohan S. Wakade
- Department of Pediatrics, Carver College of Medicine, University of Iowa, Iowa City, Iowa, USA
| | - Melanie Wellington
- Department of Pediatrics, Carver College of Medicine, University of Iowa, Iowa City, Iowa, USA
| | - Damian J. Krysan
- Department of Pediatrics, Carver College of Medicine, University of Iowa, Iowa City, Iowa, USA
- Department of Molecular Physiology and Biophysics, Carver College of Medicine, University of Iowa, Iowa City, Iowa, USA
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12
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Nickerson KW, Gutzmann DJ, Boone CHT, Pathirana RU, Atkin AL. Physiological adventures in Candida albicans: farnesol and ubiquinones. Microbiol Mol Biol Rev 2024; 88:e0008122. [PMID: 38436263 PMCID: PMC10966945 DOI: 10.1128/mmbr.00081-22] [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] [Indexed: 03/05/2024] Open
Abstract
SUMMARYFarnesol was first identified as a quorum-sensing molecule, which blocked the yeast to hyphal transition in Candida albicans, 22 years ago. However, its interactions with Candida biology are surprisingly complex. Exogenous (secreted or supplied) farnesol can also act as a virulence factor during pathogenesis and as a fungicidal agent triggering apoptosis in other competing fungi. Farnesol synthesis is turned off both during anaerobic growth and in opaque cells. Distinctly different cellular responses are observed as exogenous farnesol levels are increased from 0.1 to 100 µM. Reported changes include altered morphology, stress response, pathogenicity, antibiotic sensitivity/resistance, and even cell lysis. Throughout, there has been a dearth of mechanisms associated with these observations, in part due to the absence of accurate measurement of intracellular farnesol levels (Fi). This obstacle has recently been overcome, and the above phenomena can now be viewed in terms of changing Fi levels and the percentage of farnesol secreted. Critically, two aspects of isoprenoid metabolism present in higher organisms are absent in C. albicans and likely in other yeasts. These are pathways for farnesol salvage (converting farnesol to farnesyl pyrophosphate) and farnesylcysteine cleavage, a necessary step in the turnover of farnesylated proteins. Together, these developments suggest a unifying model, whereby high, threshold levels of Fi regulate which target proteins are farnesylated or the extent to which they are farnesylated. Thus, we suggest that the diversity of cellular responses to farnesol reflects the diversity of the proteins that are or are not farnesylated.
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Affiliation(s)
| | - Daniel J. Gutzmann
- School of Biological Sciences, University of Nebraska, Lincoln, Nebraska, USA
| | - Cory H. T. Boone
- School of Biological Sciences, University of Nebraska, Lincoln, Nebraska, USA
| | - Ruvini U. Pathirana
- Department of Biology and Chemistry, Texas A&M International University, Laredo, Texas, USA
| | - Audrey L. Atkin
- School of Biological Sciences, University of Nebraska, Lincoln, Nebraska, USA
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13
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Wakade RS, Wellington M, Krysan DJ. The role of the C. albicans transcriptional repressor NRG1 during filamentation and disseminated candidiasis is strain dependent. mSphere 2024; 9:e0078523. [PMID: 38376205 PMCID: PMC10964420 DOI: 10.1128/msphere.00785-23] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2023] [Accepted: 01/26/2024] [Indexed: 02/21/2024] Open
Abstract
Candida albicans is one of the most common causes of superficial and invasive fungal diseases in humans. Its ability to cause disease is closely linked to its ability to undergo a morphological transition from budding yeast to filamentous forms (hyphae and pseudohyphae). The extent to which C. albicans strains isolated from patients undergo filamentation varies significantly. In addition, the filamentation phenotypes of mutants involving transcription factors that positively regulate hyphal morphogenesis can also vary from strain to strain. Here, we characterized the virulence, in vitro and in vivo filamentation, and in vitro and in vivo hypha-associated gene expression profiles for four poorly filamenting C. albicans isolates and their corresponding deletion mutants of the repressor of filamentation NRG1. The two most virulent strains, 57055 and 78048, show robust in vivo filamentation but are predominately yeast phase under in vitro hypha induction; the two low-virulence strains (94015 and 78042) do not undergo filamentation well under either condition. In vitro, deletion of NRG1 increases hyphae formation in the SC5314 derivative SN250, but only pseudohyphae are formed in the clinical isolates. Deletion of NRG1 modestly increased the virulence of 78042, which was accompanied by increased expression of hypha-associated genes without an increase in filamentation. Strikingly, deletion of NRG1 in 78048 reduced filamentation in vivo, expression of candidalysin (ECE1), and virulence without dramatically altering establishment of infection. Thus, the function of the conserved repressor NRG1 in C. albicans shows strain-based heterogeneity during infection.IMPORTANCEClinical isolates of the human fungal pathogen Candida albicans show significant variation in their ability to undergo in vitro filamentation and in the function of well-characterized transcriptional regulators of filamentation. Here, we show that Nrg1, a key repressor of filamentation and filament specific gene expression in standard reference strains, has strain-dependent functions, particularly during infection. Most strikingly, loss of NRG1 function can reduce filamentation, hypha-specific gene expression such as the toxin candidalysin, and virulence in some strains. Our data emphasize that the functions of seemingly fundamental and well-conserved transcriptional regulators such as Nrg1 are contextual with respect to both environment and genetic backgrounds.
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Affiliation(s)
- Rohan S. Wakade
- Department of Pediatrics, Carver College of Medicine, University of Iowa, Iowa City, Iowa, USA
| | - Melanie Wellington
- Department of Pediatrics, Carver College of Medicine, University of Iowa, Iowa City, Iowa, USA
| | - Damian J. Krysan
- Department of Pediatrics, Carver College of Medicine, University of Iowa, Iowa City, Iowa, USA
- Department of Molecular Physiology and Biophysics, Carver College of Medicine, University of Iowa, Iowa City, Iowa, USA
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14
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Alonso-Monge R, Cortés-Prieto I, Román E, Pla J. Morphogenetic transitions in the adaptation of Candida albicans to the mammalian gut. Microbes Infect 2024; 26:105253. [PMID: 37977323 DOI: 10.1016/j.micinf.2023.105253] [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: 06/06/2023] [Revised: 11/06/2023] [Accepted: 11/12/2023] [Indexed: 11/19/2023]
Abstract
Candida albicans is a pathobiont in humans that forms part of the mycobiota in healthy individuals and can cause different pathologies upon alterations of the host defenses. The mammalian gut is clinically relevant as this niche is the most common pool for bloodstream-derived infections. The ability of C. albicans to switch from yeast to hypha has been related to the commensal-to-pathogen transition and is, therefore, considered relevant in virulence. Recently, filaments have been implicated in the humoral response in the gut. C. albicans exhibits other morphologies that play different roles in pathogenicity and commensalism. This review focuses on the role of these morphological transitions in C. albicans proliferation and its establishment as a commensal in the mammalian gut, paying special attention to the transcription factors involved in their regulation.
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Affiliation(s)
- Rebeca Alonso-Monge
- Departamento de Microbiología y Parasitología, Facultad de Farmacia, Universidad Complutense de Madrid, Plaza de Ramón y Cajal s/n, 28040 Madrid, Spain.
| | - Isabel Cortés-Prieto
- Departamento de Microbiología y Parasitología, Facultad de Farmacia, Universidad Complutense de Madrid, Plaza de Ramón y Cajal s/n, 28040 Madrid, Spain.
| | - Elvira Román
- Departamento de Microbiología y Parasitología, Facultad de Farmacia, Universidad Complutense de Madrid, Plaza de Ramón y Cajal s/n, 28040 Madrid, Spain.
| | - Jesús Pla
- Departamento de Microbiología y Parasitología, Facultad de Farmacia, Universidad Complutense de Madrid, Plaza de Ramón y Cajal s/n, 28040 Madrid, Spain.
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15
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Liang SH, Sircaik S, Dainis J, Kakade P, Penumutchu S, McDonough LD, Chen YH, Frazer C, Schille TB, Allert S, Elshafee O, Hänel M, Mogavero S, Vaishnava S, Cadwell K, Belenky P, Perez JC, Hube B, Ene IV, Bennett RJ. The hyphal-specific toxin candidalysin promotes fungal gut commensalism. Nature 2024; 627:620-627. [PMID: 38448595 PMCID: PMC11230112 DOI: 10.1038/s41586-024-07142-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2022] [Accepted: 01/31/2024] [Indexed: 03/08/2024]
Abstract
The fungus Candida albicans frequently colonizes the human gastrointestinal tract, from which it can disseminate to cause systemic disease. This polymorphic species can transition between growing as single-celled yeast and as multicellular hyphae to adapt to its environment. The current dogma of C. albicans commensalism is that the yeast form is optimal for gut colonization, whereas hyphal cells are detrimental to colonization but critical for virulence1-3. Here, we reveal that this paradigm does not apply to multi-kingdom communities in which a complex interplay between fungal morphology and bacteria dictates C. albicans fitness. Thus, whereas yeast-locked cells outcompete wild-type cells when gut bacteria are absent or depleted by antibiotics, hyphae-competent wild-type cells outcompete yeast-locked cells in hosts with replete bacterial populations. This increased fitness of wild-type cells involves the production of hyphal-specific factors including the toxin candidalysin4,5, which promotes the establishment of colonization. At later time points, adaptive immunity is engaged, and intestinal immunoglobulin A preferentially selects against hyphal cells1,6. Hyphal morphotypes are thus under both positive and negative selective pressures in the gut. Our study further shows that candidalysin has a direct inhibitory effect on bacterial species, including limiting their metabolic output. We therefore propose that C. albicans has evolved hyphal-specific factors, including candidalysin, to better compete with bacterial species in the intestinal niche.
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Affiliation(s)
- Shen-Huan Liang
- Department of Molecular Microbiology and Immunology, Brown University, Providence, RI, USA
| | - Shabnam Sircaik
- Department of Molecular Microbiology and Immunology, Brown University, Providence, RI, USA
| | - Joseph Dainis
- Department of Molecular Microbiology and Immunology, Brown University, Providence, RI, USA
| | - Pallavi Kakade
- Department of Molecular Microbiology and Immunology, Brown University, Providence, RI, USA
| | - Swathi Penumutchu
- Department of Molecular Microbiology and Immunology, Brown University, Providence, RI, USA
| | - Liam D McDonough
- Department of Molecular Microbiology and Immunology, Brown University, Providence, RI, USA
| | - Ying-Han Chen
- Division of Gastroenterology, Department of Medicine, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA, USA
| | - Corey Frazer
- Department of Molecular Microbiology and Immunology, Brown University, Providence, RI, USA
| | - Tim B Schille
- Department of Microbial Pathogenicity Mechanisms, Leibniz Institute for Natural Product Research and Infection Biology-Hans Knoell Institute (HKI), Jena, Germany
- Cluster of Excellence Balance of the Microverse, Friedrich Schiller University Jena, Jena, Germany
| | - Stefanie Allert
- Department of Microbial Pathogenicity Mechanisms, Leibniz Institute for Natural Product Research and Infection Biology-Hans Knoell Institute (HKI), Jena, Germany
| | - Osama Elshafee
- Department of Microbial Pathogenicity Mechanisms, Leibniz Institute for Natural Product Research and Infection Biology-Hans Knoell Institute (HKI), Jena, Germany
| | - Maria Hänel
- Department of Microbial Pathogenicity Mechanisms, Leibniz Institute for Natural Product Research and Infection Biology-Hans Knoell Institute (HKI), Jena, Germany
| | - Selene Mogavero
- Department of Microbial Pathogenicity Mechanisms, Leibniz Institute for Natural Product Research and Infection Biology-Hans Knoell Institute (HKI), Jena, Germany
| | - Shipra Vaishnava
- Department of Molecular Microbiology and Immunology, Brown University, Providence, RI, USA
| | - Ken Cadwell
- Division of Gastroenterology, Department of Medicine, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA, USA
| | - Peter Belenky
- Department of Molecular Microbiology and Immunology, Brown University, Providence, RI, USA
| | - J Christian Perez
- Department of Microbiology and Molecular Genetics, McGovern Medical School, The University of Texas Health Science Center at Houston, Houston, TX, USA
| | - Bernhard Hube
- Department of Microbial Pathogenicity Mechanisms, Leibniz Institute for Natural Product Research and Infection Biology-Hans Knoell Institute (HKI), Jena, Germany.
- Cluster of Excellence Balance of the Microverse, Friedrich Schiller University Jena, Jena, Germany.
- Institute of Microbiology, Friedrich Schiller University Jena, Jena, Germany.
| | - Iuliana V Ene
- Institut Pasteur, Université Paris Cité, Fungal Heterogeneity Group, Paris, France
| | - Richard J Bennett
- Department of Molecular Microbiology and Immunology, Brown University, Providence, RI, USA.
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16
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Alvira-Arill GR, Willems HME, Fortwendel JP, Yarbrough A, Tansmore J, Sierra CM, Bashqoy F, Stultz JS, Peters BM. Impact of Intravenous Fat Emulsion Choice on Candida Biofilm, Hyphal Growth, and Catheter-Related Bloodstream Infections in Pediatric Patients. J Infect Dis 2024; 229:588-598. [PMID: 38001054 PMCID: PMC10873182 DOI: 10.1093/infdis/jiad527] [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: 08/11/2023] [Revised: 11/15/2023] [Accepted: 11/22/2023] [Indexed: 11/26/2023] Open
Abstract
BACKGROUND Use of mixed-oil (MO) intravenous fat emulsion (IFE) was shown to inhibit Candida albicans biofilm formation and overall rate of catheter-related bloodstream infections (CR-BSIs) compared with soybean-oil (SO) IFE). We aimed to delineate this inhibitory mechanism and impact of IFE choice on distribution of fungal CR-BSIs. METHODS Transcriptional profiling was conducted on C. albicans grown in SO-IFE, MO-IFE, or SO-IFE with capric acid. Overexpression strains of shared down-regulated genes were constructed using a tetracycline-off system to assess hypha and biofilm formation in IFEs. A 5-year retrospective multicenter cohort study was performed to assess differences in CR-BSIs caused by Candida species based on the IFE formulation received in pediatric patients. RESULTS Genes significantly down-regulated in MO-IFE and SO-IFE with capric acid included CDC11, HGC1, and UME6. Overexpression of HGC1 or UME6 enabled filamentation in capric acid and MO-IFE. Interestingly, only overexpression of UME6 was sufficient to rescue biofilm growth in MO-IFE. MO-IFE administration was associated with a higher proportion of non-albicans Candida versus C. albicans CR-BSIs (42% vs 33%; odds ratio, 1.22 [95% confidence interval, .46-3.26]). CONCLUSIONS MO-IFE affects C. albicans biofilm formation and hyphal growth via a UME6-dependent mechanism. A numerical but not statistically significant difference in distribution of Candida spp. among CR-BSIs was observed.
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Affiliation(s)
- Gustavo R Alvira-Arill
- Department of Clinical Pharmacy and Outcomes Sciences, College of Pharmacy, Medical University of South Carolina, Charleston, South Carolina, USA
- Department of Clinical Pharmacy and Translational Science, College of Pharmacy, University of Tennessee Health Science Center, Memphis, Tennessee, USA
- Department of Pharmacy, Le Bonheur Children's Hospital, Memphis, Tennessee, USA
| | - Hubertine M E Willems
- Department of Clinical Pharmacy and Translational Science, College of Pharmacy, University of Tennessee Health Science Center, Memphis, Tennessee, USA
| | - Jabez P Fortwendel
- Department of Clinical Pharmacy and Translational Science, College of Pharmacy, University of Tennessee Health Science Center, Memphis, Tennessee, USA
| | - April Yarbrough
- Department of Pharmacy, Children's of Alabama, Birmingham, Alabama, USA
| | - Jessica Tansmore
- Department of Pharmacy, Nationwide Children's Hospital, Columbus, Ohio, USA
| | - Caroline M Sierra
- Department of Pharmacy Practice, School of Pharmacy, Loma Linda University, Loma Linda, California, USA
| | - Ferras Bashqoy
- Department of Pharmacy, Hassenfeld Children's Hospital at NYU Langone, NewYork, New York, USA
| | - Jeremy S Stultz
- Department of Clinical Pharmacy and Translational Science, College of Pharmacy, University of Tennessee Health Science Center, Memphis, Tennessee, USA
- Department of Pharmacy, Le Bonheur Children's Hospital, Memphis, Tennessee, USA
| | - Brian M Peters
- Department of Clinical Pharmacy and Translational Science, College of Pharmacy, University of Tennessee Health Science Center, Memphis, Tennessee, USA
- Department of Microbiology, Immunology, and Biochemistry, College of Medicine, University of Tennessee Health Science Center, Memphis, Tennessee, USA
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17
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Pathan SK, Shelar A, Deshmukh S, Kalam Khan FA, Ansari SA, Ansari IA, Patil RB, Arote R, Bhusnure O, Patil RH, Sangshetti JN. Exploring antibiofilm potential of some new imidazole analogs against C. albicans: synthesis, antifungal activity, molecular docking and molecular dynamics studies. J Biomol Struct Dyn 2024:1-17. [PMID: 38174407 DOI: 10.1080/07391102.2023.2296604] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2023] [Accepted: 12/04/2023] [Indexed: 01/05/2024]
Abstract
A series of 1, 2, 4, 5-tetrasubstituted imidazole derivatives were synthesized and their antibiofilm potential against Candida albicans was evaluated in vitro. Two of the synthesized derivatives 5e (IC50 = 25 µg/mL) and 5m (IC50 = 6 µg/mL),displayed better antifungal and antibiofilm potential than the standard drug Fluconazole (IC50 = 40 µg/mL) against C. albicans. Based on the in vitro results, we escalated the real time polymerase chain reaction (RT-PCR) analysis to gain knowledge of the enzymes expressed in the generation and maintenance of biofilms and the mechanism of biofilm inhibition by the synthesized analogues. We then investigated the possible interactions of the synthesized compounds in inhibiting agglutinin-like proteins, namely Als3, Als4 and Als6 were prominently down-regulated using in-silico molecular docking analysis against the previously available crystal structure of Als3 and constructed structure of Als4 and Als6 using the SWISS-MODEL server. The stability and energy of the agglutinin-like proteins-ligand complexes were evaluated using molecular dynamics simulations (MDS). According to the 100 ns MDS, all the compounds remained stable, formed a maximum of 3, and on average 2 hydrogen bonds, and Gibb's free energy landscape analysis suggested greater affinity of the compounds 5e and 5m toward Als4 protein.Communicated by Ramaswamy H. Sarma.
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Affiliation(s)
- Shahebaaz K Pathan
- Y. B. Chavan College of Pharmacy, Dr. Rafiq Zakaria Campus, Rauza Baugh, Aurangabad, India
| | - Amruta Shelar
- Department of Technology, Savitribai Phule Pune University, Pune, India
| | | | | | - Siddique Akber Ansari
- Department of Pharmaceutical Chemistry, College of Pharmacy, King Saud University, Riyadh, Saudi Arabia
| | - Irfan Aamer Ansari
- Department of Drug Science and Technology, University of Turin, Turin, Italy
| | - Rajesh B Patil
- Sinhgad Technical Education Society's Sinhgad College of Pharmacy, Pune, India
| | - Rohidas Arote
- Center for Nano Materials and Science (CNMS), Jain University, Bangalore, India
| | - Omprakash Bhusnure
- Channabasweshwar Channabasweshwar Pharmacy College (Degree), Latur, India
| | - Rajendra H Patil
- Department of Biotechnology, Savitribai Phule Pune University, Pune, India
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18
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Thombre D, Shelar A, Nakhale S, Khairnar B, Karale N, Sangshetti J, Nile SH, Patil R. Green synthesis of biogenic selenium nanoparticles functionalized with ginger dietary extract targeting virulence factor and biofilm formation in Candida albicans. Microb Pathog 2024; 186:106462. [PMID: 38030019 DOI: 10.1016/j.micpath.2023.106462] [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: 10/10/2023] [Revised: 11/20/2023] [Accepted: 11/23/2023] [Indexed: 12/01/2023]
Abstract
To treat the systemic infections caused by Candida albicans (C. albicans), various drugs have been used, however, infections still persisted due to virulence factors and increasing antifungal resistance. As a solution to this problem, we synthesized selenium nanoparticles (SeNPs) by using Bacillus cereus bacteria. This is the first study to report a higher (70 %) reduction of selenite ions into SeNPs in under 6 h. The as-synthesized, biogenic SeNPs were used to deliver bioactive constituents of aqueous extract of ginger for inhibiting the growth and biofilm (virulence factors) in C. albicans. UV-visible spectroscopy revealed a characteristic absorption at 280 nm, and Raman spectroscopy showed a characteristic peak shift at 253 cm-1 for the biogenic SeNPs. The synthesized SeNPs are spherical with 240-250 nm in size as determined by electron microscopy. Fourier transform infrared spectroscopy confirmed the functionalization of antifungal constituents of ginger over the SeNPs (formation of Ginger@SeNPs nanoconjugates). In contrast to biogenic SeNPs, nanoconjugates were active against C. albicans for inhibiting growth and biofilm formation. In order to reveal antifungal mechanism of nanoconjugates', real-time polymerase chain reaction (RT-PCR) analysis was performed, according to RT-PCR analysis, the nanoconjugates target virulence genes involved in C. albicans hyphae and biofilm formation. Nanoconjugates inhibited 25 % growth of human embryonic kidney (HEK) 293 cell line, indicating moderate cytotoxicity of active nanoconjugates in an in-vitro cytotoxicity study. Therefore, biogenic SeNPs conjugated with ginger dietary extract may be a potential antifungal agent and drug carrier for inhibiting C. albicans growth and biofilm formation.
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Affiliation(s)
- Dipalee Thombre
- Department of Biotechnology, Savitribai Phule Pune University, Pune, 411007, India
| | - Amruta Shelar
- Department of Technology, Savitribai Phule Pune University, Pune, 411007, India
| | - Sweta Nakhale
- PES's Modern College of Arts, Science and Commerce Ganeshkhind. Pune, Maharashtra, 411053, India
| | - Bhushan Khairnar
- Interdisciplinary School of Science, Savitribai Phule Pune University, Pune, 411007, India
| | - Netaji Karale
- Vidya Pratishthan's Arts, Science and Commerce College, Baramati, 413133, Maharashtra, India
| | | | - Shivraj Hariram Nile
- Division of Food and Nutritional Biotechnology, DBT-National Agri-Food Biotechnology Institute (NABI), Sector-81, Knowledge City, S.A.S. Nagar, Mohali, 140306, Punjab, India.
| | - Rajendra Patil
- Department of Biotechnology, Savitribai Phule Pune University, Pune, 411007, India.
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19
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Zeng G, Xu X, Kok YJ, Deng FS, Ling Chow EW, Gao J, Bi X, Wang Y. Cytochrome c regulates hyphal morphogenesis by interfering with cAMP-PKA signaling in Candida albicans. Cell Rep 2023; 42:113473. [PMID: 37980562 DOI: 10.1016/j.celrep.2023.113473] [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: 06/19/2023] [Revised: 10/17/2023] [Accepted: 11/06/2023] [Indexed: 11/21/2023] Open
Abstract
In the human fungal pathogen Candida albicans, invasive hyphal growth is a well-recognized virulence trait. We employed transposon-mediated genome-wide mutagenesis, revealing that inactivating CTM1 blocks hyphal growth. CTM1 encodes a lysine (K) methyltransferase, which trimethylates cytochrome c (Cyc1) at K79. Mutants lacking CTM1 or expressing cyc1K79A grow as yeast under hyphae-inducing conditions, indicating that unmethylated Cyc1 suppresses hyphal growth. Transcriptomic analyses detected increased levels of the hyphal repressor NRG1 and decreased levels of hyphae-specific genes in ctm1Δ/Δ and cyc1K79A mutants, suggesting cyclic AMP (cAMP)-protein kinase A (PKA) signaling suppression. Co-immunoprecipitation and in vitro kinase assays demonstrated that unmethylated Cyc1 inhibits PKA kinase activity. Surprisingly, hyphae-defective ctm1Δ/Δ and cyc1K79A mutants remain virulent in mice due to accelerated proliferation. Our results unveil a critical role for cytochrome c in maintaining the virulence of C. albicans by orchestrating proliferation, growth mode, and metabolism. Importantly, this study identifies a biological function for lysine methylation on cytochrome c.
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Affiliation(s)
- Guisheng Zeng
- A(∗)STAR Infectious Diseases Labs (A(∗)STAR ID Labs), Agency for Science, Technology and Research (A(∗)STAR), 8A Biomedical Grove, #05-13 Immunos, Singapore 138648, Singapore.
| | - Xiaoli Xu
- A(∗)STAR Infectious Diseases Labs (A(∗)STAR ID Labs), Agency for Science, Technology and Research (A(∗)STAR), 8A Biomedical Grove, #05-13 Immunos, Singapore 138648, Singapore
| | - Yee Jiun Kok
- Bioprocessing Technology Institute, 20 Biopolis Way, #06-01 Centros, Singapore 138668, Singapore
| | - Fu-Sheng Deng
- Department of Biochemical Science and Technology, College of Life Science, National Taiwan University, Taipei 10617, Taiwan
| | - Eve Wai Ling Chow
- A(∗)STAR Infectious Diseases Labs (A(∗)STAR ID Labs), Agency for Science, Technology and Research (A(∗)STAR), 8A Biomedical Grove, #05-13 Immunos, Singapore 138648, Singapore
| | - Jiaxin Gao
- State Key Laboratory of Mycology, Institute of Microbiology, Chinese Academy of Sciences, Beijing 100101, China
| | - Xuezhi Bi
- Bioprocessing Technology Institute, 20 Biopolis Way, #06-01 Centros, Singapore 138668, Singapore; Duke-NUS Medical School, National University of Singapore, Singapore 169857, Singapore
| | - Yue Wang
- A(∗)STAR Infectious Diseases Labs (A(∗)STAR ID Labs), Agency for Science, Technology and Research (A(∗)STAR), 8A Biomedical Grove, #05-13 Immunos, Singapore 138648, Singapore; Department of Biochemistry, Yong Loo Lin School of Medicine, National University of Singapore, Singapore 117597, Singapore.
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20
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McCrory C, Verma J, Tucey TM, Turner R, Weerasinghe H, Beilharz TH, Traven A. The short-chain fatty acid crotonate reduces invasive growth and immune escape of Candida albicans by regulating hyphal gene expression. mBio 2023; 14:e0260523. [PMID: 37929941 PMCID: PMC10746253 DOI: 10.1128/mbio.02605-23] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2023] [Accepted: 10/02/2023] [Indexed: 11/07/2023] Open
Abstract
IMPORTANCE Macrophages curtail the proliferation of the pathogen Candida albicans within human body niches. Within macrophages, C. albicans adapts its metabolism and switches to invasive hyphal morphology. These adaptations enable fungal growth and immune escape by triggering macrophage lysis. Transcriptional programs regulate these metabolic and morphogenetic adaptations. Here we studied the roles of chromatin in these processes and implicate lysine crotonylation, a histone mark regulated by metabolism, in hyphal morphogenesis and macrophage interactions by C. albicans. We show that the short-chain fatty acid crotonate increases histone crotonylation, reduces hyphal formation within macrophages, and slows macrophage lysis and immune escape of C. albicans. Crotonate represses hyphal gene expression, and we propose that C. albicans uses diverse acylation marks to regulate its cell morphology in host environments. Hyphal formation is a virulence property of C. albicans. Therefore, a further importance of our study stems from identifying crotonate as a hyphal inhibitor.
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Affiliation(s)
- Christopher McCrory
- Department of Biochemistry and Molecular Biology and Infection Program, Biomedicine Discovery Institute, Monash University, Clayton, Australia
- Centre to Impact AMR, Monash University, Clayton, Australia
| | - Jiyoti Verma
- Department of Biochemistry and Molecular Biology and Infection Program, Biomedicine Discovery Institute, Monash University, Clayton, Australia
| | - Timothy M. Tucey
- Department of Biochemistry and Molecular Biology and Infection Program, Biomedicine Discovery Institute, Monash University, Clayton, Australia
| | - Rachael Turner
- Department of Biochemistry and Molecular Biology and Stem Cells and Development Program, Biomedicine Discovery Institute, Monash University, Clayton, Australia
| | - Harshini Weerasinghe
- Department of Biochemistry and Molecular Biology and Infection Program, Biomedicine Discovery Institute, Monash University, Clayton, Australia
- Centre to Impact AMR, Monash University, Clayton, Australia
| | - Traude H. Beilharz
- Department of Biochemistry and Molecular Biology and Infection Program, Biomedicine Discovery Institute, Monash University, Clayton, Australia
- Department of Biochemistry and Molecular Biology and Stem Cells and Development Program, Biomedicine Discovery Institute, Monash University, Clayton, Australia
| | - Ana Traven
- Department of Biochemistry and Molecular Biology and Infection Program, Biomedicine Discovery Institute, Monash University, Clayton, Australia
- Centre to Impact AMR, Monash University, Clayton, Australia
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21
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Case NT, Westman J, Hallett MT, Plumb J, Farheen A, Maxson ME, MacAlpine J, Liston SD, Hube B, Robbins N, Whitesell L, Grinstein S, Cowen LE. Respiration supports intraphagosomal filamentation and escape of Candida albicans from macrophages. mBio 2023; 14:e0274523. [PMID: 38038475 PMCID: PMC10746240 DOI: 10.1128/mbio.02745-23] [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: 10/07/2023] [Accepted: 10/16/2023] [Indexed: 12/02/2023] Open
Abstract
IMPORTANCE Candida albicans is a leading human fungal pathogen that often causes life-threatening infections in immunocompromised individuals. The ability of C. albicans to transition between yeast and filamentous forms is key to its virulence, and this occurs in response to many host-relevant cues, including engulfment by host macrophages. While previous efforts identified C. albicans genes required for filamentation in other conditions, the genes important for this morphological transition upon internalization by macrophages remained largely enigmatic. Here, we employed a functional genomic approach to identify genes that enable C. albicans filamentation within macrophages and uncovered a role for the mitochondrial ribosome, respiration, and the SNF1 AMP-activated kinase complex. Additionally, we showed that glucose uptake and glycolysis by macrophages support C. albicans filamentation. This work provides insights into the metabolic dueling that occurs during the interaction of C. albicans with macrophages and identifies vulnerabilities in C. albicans that could serve as promising therapeutic targets.
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Affiliation(s)
- Nicola T. Case
- Department of Molecular Genetics, University of Toronto, Toronto, Ontario, Canada
| | - Johannes Westman
- Program in Cell Biology, Peter Gilgan Centre for Research and Learning, The Hospital for Sick Children, Toronto, Ontario, Canada
| | | | - Jonathan Plumb
- Program in Cell Biology, Peter Gilgan Centre for Research and Learning, The Hospital for Sick Children, Toronto, Ontario, Canada
| | - Aiman Farheen
- Department of Molecular Genetics, University of Toronto, Toronto, Ontario, Canada
| | - Michelle E. Maxson
- Program in Cell Biology, The Hospital for Sick Children, Toronto, Ontario, Canada
| | - Jessie MacAlpine
- Department of Molecular Genetics, University of Toronto, Toronto, Ontario, Canada
| | - Sean D. Liston
- Department of Molecular Genetics, University of Toronto, Toronto, Ontario, Canada
| | - Bernhard Hube
- Department of Microbial Pathogenicity Mechanisms, Leibniz Institute for Natural Product Research and Infection Biology, Hans Knoell Institute, Jena, Germany
- Institute of Microbiology, Friedrich Schiller University, Jena, Germany
| | - Nicole Robbins
- Department of Molecular Genetics, University of Toronto, Toronto, Ontario, Canada
| | - Luke Whitesell
- Department of Molecular Genetics, University of Toronto, Toronto, Ontario, Canada
| | - Sergio Grinstein
- Program in Cell Biology, Peter Gilgan Centre for Research and Learning, The Hospital for Sick Children, Toronto, Ontario, Canada
- Department of Biochemistry, University of Toronto, Toronto, Ontario, Canada
- Keenan Research Center of the Li Ka Shing Knowledge Institute, St. Michael’s Hospital, Toronto, Ontario, Canada
| | - Leah E. Cowen
- Department of Molecular Genetics, University of Toronto, Toronto, Ontario, Canada
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22
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Wakade RS, Wellington M, Krysan DJ. The role of the C. albicans transcriptional repressor NRG1 during filamentation and disseminated candidiasis is strain-dependent. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.12.15.571891. [PMID: 38168187 PMCID: PMC10760072 DOI: 10.1101/2023.12.15.571891] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/05/2024]
Abstract
Candida albicans is one of the most common causes of superficial and invasive fungal disease in humans. Its ability to cause disease has been closely linked to its ability to undergo a morphological transition from budding yeast to filamentous forms (hyphae and pseudohyphae). The ability of C. albicans strains isolated from patients to undergo filamentation varies significantly. In addition, the filamentation phenotypes of mutants involving transcription factors that positively regulate hyphal morphogenesis can also vary from strain to strain. Here, we characterized the virulence, in vitro and in vivo filamentation, and in vitro and in vivo hypha-associated gene expression profiles of four poorly filamenting C. albicans isolates and their corresponding deletion mutants of the repressor of filamentation NRG1. The two most virulent strains, 57055 and 78048, show robust in vivo filamentation while remaining predominately yeast phase exposed to RPMI+10% bovine calf serum at 37°C; the two low virulence strains (94015 and 78042) do not filament well under either condition. Deletion of NRG1 increases hyphae formation in the SC5314 derivative SN250 but only pseudohyphae are formed in the clinical isolates in vivo. Deletion of NRG1 modestly increased the virulence of 78042 which was accompanied by increased expression of hyphae-associated genes without an increase in filamentation. Strikingly, deletion of NRG1 in 78048 reduced filamentation, expression of candidalysin (ECE1) and virulence in vivo without dramatically altering establishment of infection. Thus, the function of NRG1 varies significantly within this set of C. albicans isolates and can actually suppress filamentation in vivo.
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Affiliation(s)
- Rohan S. Wakade
- Department of Pediatrics, Carver College of Medicine, University of Iowa, Iowa City IA
| | - Melanie Wellington
- Department of Pediatrics, Carver College of Medicine, University of Iowa, Iowa City IA
| | - Damian J. Krysan
- Department of Pediatrics, Carver College of Medicine, University of Iowa, Iowa City IA
- Department of Molecular Physiology and Biophysics, Carver College of Medicine, University of Iowa, Iowa City IA
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23
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Memariani M, Memariani H. Antifungal properties of cathelicidin LL-37: current knowledge and future research directions. World J Microbiol Biotechnol 2023; 40:34. [PMID: 38057654 DOI: 10.1007/s11274-023-03852-5] [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: 10/17/2023] [Accepted: 11/22/2023] [Indexed: 12/08/2023]
Abstract
The threat of fungal diseases is substantially underestimated worldwide, but they have serious consequences for humans, animals, and plants. Given the limited number of existing antifungal drugs together with the emergence of drug-resistant strains, many researchers have actively sought alternatives or adjuvants to antimycotics. The best way to tackle these issues is to unearth potential antifungal agents with new modes of action. Antimicrobial peptides are being hailed as a promising source of novel antimicrobials since they exhibit rapid and broad-spectrum microbicidal activities with a reduced likelihood of developing drug resistance. Recent years have witnessed an explosion in knowledge on microbicidal activity of LL-37, the sole human cathelicidin. Herein, we provide a summary of the current understanding about antifungal properties of LL-37, with particular emphasis on its molecular mechanisms. We further illustrate fruitful areas for future research. LL-37 is able to inhibit the growth of clinically and agronomically relevant fungi including Aspergillus, Candida, Colletotrichum, Fusarium, Malassezia, Pythium, and Trichophyton. Destruction of the cell wall integrity, membrane permeabilization, induction of oxidative stress, disruption of endoplasmic reticulum homeostasis, formation of autophagy-like structures, alterations in expression of numerous fungal genes, and inhibition of cell cycle progression are the key mechanisms underlying antifungal effects of LL-37. Burgeoning evidence also suggests that LL-37 may act as a potential anti-virulence peptide. It is hoped that this review will not only motivate researchers to conduct more detailed studies in this field, but also inspire further innovations in the design of LL-37-based drugs for the treatment of fungal infections.
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Affiliation(s)
- Mojtaba Memariani
- Department of Medical Microbiology, Tehran University of Medical Sciences, Tehran, Iran
| | - Hamed Memariani
- Department of Medical Microbiology, Tehran University of Medical Sciences, Tehran, Iran.
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24
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Anand R, Kashif M, Pandit A, Babu R, Singh AP. Reprogramming in Candida albicans Gene Expression Network under Butanol Stress Abrogates Hyphal Development. Int J Mol Sci 2023; 24:17227. [PMID: 38139056 PMCID: PMC10743114 DOI: 10.3390/ijms242417227] [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: 07/20/2023] [Revised: 11/02/2023] [Accepted: 11/03/2023] [Indexed: 12/24/2023] Open
Abstract
Candida albicans is the causative agent of invasive fungal infections. Its hyphae-forming ability is regarded as one of the important virulence factors. To unravel the impact of butanol on Candida albicans, it was placed in O+ve complete human serum with butanol (1% v/v). The Candida transcriptome under butanol stress was then identified by mRNA sequencing. Studies including electron microscopy demonstrated the inhibition of hyphae formation in Candida under the influence of butanol, without any significant alteration in growth rate. The numbers of genes upregulated in the butanol in comparison to the serum alone were 1061 (20 min), 804 (45 min), and 537 (120 min). Candida cells exhibited the downregulation of six hypha-specific transcription factors and the induction of four repressor/regulator genes. Many of the hypha-specific genes exhibited repression in the medium with butanol. The genes related to adhesion also exhibited repression, whereas, among the heat-shock genes, three showed inductions in the presence of butanol. The fungal-specific genes exhibited induction as well as repression in the butanol-treated Candida cells. Furthermore, ten upregulated genes formed the core stress gene set in the presence of butanol. In the gene ontology analysis, enrichment of the processes related to non-coding RNA, ribosome biosynthesis, and metabolism was observed in the induced gene set. On the other side, a few GO biological process terms, including biofilm formation and filamentous growth, were enriched in the repressed gene set. Taken together, under butanol stress, Candida albicans is unable to extend hyphae and shows growth by budding. Many of the genes with perturbed expression may have fitness or virulence attributes and may provide prospective sites of antifungal targets against C. albicans.
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Affiliation(s)
- Rajesh Anand
- Infectious Disease Laboratory, National Institute of Immunology, New Delhi 110067, India; (R.A.)
| | - Mohammad Kashif
- Infectious Disease Laboratory, National Institute of Immunology, New Delhi 110067, India; (R.A.)
| | - Awadhesh Pandit
- Next Generation Sequencing Facility, National Institute of Immunology, New Delhi 110067, India
| | - Ram Babu
- Department of Botany, Kirori Mal College, University of Delhi, Delhi 110007, India
| | - Agam P. Singh
- Infectious Disease Laboratory, National Institute of Immunology, New Delhi 110067, India; (R.A.)
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25
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Brandquist ND, Lampman C, Smith EJ, Basilio L, Almansob A, Iwen PC, Blankenship JR. Significant variation of filamentation phenotypes in clinical Candida albicans strains. Front Cell Infect Microbiol 2023; 13:1207083. [PMID: 37928181 PMCID: PMC10623444 DOI: 10.3389/fcimb.2023.1207083] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2023] [Accepted: 10/02/2023] [Indexed: 11/07/2023] Open
Abstract
Introduction Candida albicans is an opportunistic human pathogen that typically resides as part of the microbiome in the gastrointestinal and genitourinary tracts of a large portion of the human population. This fungus lacks a true sexual cycle and evolves in a largely clonal pattern. The ability to cause disease is consistent across the species as strains causing systemic infections appear across the known C. albicans intra-species clades. Methods In this work, strains collected from patients with systemic C. albicans infections isolated at the Nebraska Medicine clinical laboratory were typed by MLST analysis. Since the ability to form filaments has been linked to pathogenesis in C. albicans, these clinical strains, as well as a previously genotyped set of clinical strains, were tested for their ability to filament across a variety of inducing conditions. Results Genotyping of the clinical strains demonstrated that the strains isolated at one of the major medical centers in our region were as diverse as strains collected across the United States. We demonstrated that clinical strains exhibit a variety of filamentation patterns across differing inducing conditions. The only consistent pattern observed in the entire set of clinical strains tested was an almost universal inability to filament in standard solid inducing conditions used throughout the C. albicans field. A different solid filamentation assay that produces more robust filamentation profiles from clinical strains is proposed in this study, although not all strains expected to filament in vivo were filamentous in this assay. Discussion Our data supports growing evidence that broad phenotypic diversity exists between the C. albicans type strain and clinical strains, suggesting that the type strain poorly represents filamentation patterns observed in most clinical isolates. These data further highlight the need to use diverse clinical strains in pathogenesis assays.
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Affiliation(s)
| | - Cierra Lampman
- Department of Biology, University of Nebraska at Omaha, Omaha, NE, United States
| | - Elias J. Smith
- Department of Biology, University of Nebraska at Omaha, Omaha, NE, United States
| | - Lizeth Basilio
- Department of Biology, University of Nebraska at Omaha, Omaha, NE, United States
| | - Akram Almansob
- Department of Biology, University of Nebraska at Omaha, Omaha, NE, United States
| | - Peter C. Iwen
- Nebraska Public Health Laboratory, University of Nebraska Medical Center, Omaha, NE, United States
| | - Jill R. Blankenship
- Department of Biology, University of Nebraska at Omaha, Omaha, NE, United States
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26
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Montoya C, Kurylec J, Ossa A, Orrego S. Cyclic strain of poly (methyl methacrylate) surfaces triggered the pathogenicity of Candida albicans. Acta Biomater 2023; 170:415-426. [PMID: 37625677 DOI: 10.1016/j.actbio.2023.08.037] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2023] [Revised: 07/21/2023] [Accepted: 08/17/2023] [Indexed: 08/27/2023]
Abstract
Candida albicans is an opportunistic yeast and the primary etiological factor in oral candidiasis and denture stomatitis. The pathogenesis of C. albicans could be triggered by several variables, including environmental, nutritional, and biomaterial surface cues. Specifically, biomaterial interactions are driven by different surface properties, including wettability, stiffness, and roughness. Dental biomaterials experience repetitive (cyclic) stresses from chewing and biomechanical movements. Pathogenic biofilms are formed over these biomaterial surfaces under cyclic strain. This study investigated the effect of the cyclic strain (deformation) of biomaterial surfaces on the virulence of Candida albicans. Candida biofilms were grown over Poly (methyl methacrylate) (PMMA) surfaces subjected to static (no strain) and cyclic strain with different levels (ε˜x=0.1 and 0.2%). To evaluate the biomaterial-biofilm interactions, the biofilm characteristics, yeast-to-hyphae transition, and the expression of virulent genes were measured. Results showed the biofilm biomass and metabolic activity to be significantly higher when Candida adhered to surfaces subjected to cyclic strain compared to static surfaces. Examination of the yeast-to-hyphae transition showed pseudo-hyphae cells (pathogenic) in cyclically strained biomaterial surfaces, whereas static surfaces showed spherical yeast cells (commensal). RNA sequencing was used to determine and compare the transcriptome profiles of cyclically strained and static surfaces. Genes and transcription factors associated with cell adhesion (CSH1, PGA10, and RBT5), biofilm formation (EFG1), and secretion of extracellular matrix (ECM) (CRH1, ADH5, GCA1, and GCA2) were significantly upregulated in the cyclically strained biomaterial surfaces compared to static ones. Genes and transcription factors associated with virulence (UME6 and HGC1) and the secretion of extracellular enzymes (LIP, PLB, and SAP families) were also significantly upregulated in the cyclically strained biomaterial surfaces compared to static. For the first time, this study reveals a biomaterial surface factor triggering the pathogenesis of Candida albicans, which is essential for understanding, controlling, and preventing oral infections. STATEMENT OF SIGNIFICANCE: Fungal infections produced by Candida albicans are a significant contributor to various health conditions. Candida becomes pathogenic when certain environmental conditions change, including temperature, pH, nutrients, and CO2 levels. In addition, surface properties, including wettability, stiffness, and roughness, drive the interactions between Candida and biomaterials. Clinically, Candida adheres to biomaterials that are under repetitive deformation due to body movements. In this work, we revealed that when Candida adhered to biomaterial surfaces subjected to repetitive deformation, the microorganism becomes pathogenic by increasing the formation of biofilms and the expression of virulent factors related to hyphae formation and secretion of enzymes. Findings from this work could aid the development of new strategies for treating fungal infections in medical devices or implanted biomaterials.
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Affiliation(s)
- Carolina Montoya
- Department of Oral Health Sciences, Kornberg School of Dentistry, Temple University, Philadelphia, PA, United States
| | - Julia Kurylec
- Department of Oral Health Sciences, Kornberg School of Dentistry, Temple University, Philadelphia, PA, United States
| | - Alex Ossa
- Production Engineering Department, School of Engineering, Universidad EAFIT, Medellín, Colombia
| | - Santiago Orrego
- Department of Oral Health Sciences, Kornberg School of Dentistry, Temple University, Philadelphia, PA, United States; Bioengineering Department, College of Engineering, Temple University, Philadelphia, PA, United States.
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27
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Gutzmann DJ, Kramer JJ, Toomey BM, Boone CHT, Atkin AL, Nickerson KW. Transcriptional regulation of the synthesis and secretion of farnesol in the fungus Candida albicans: examination of the Homann transcription regulator knockout collection. G3 (BETHESDA, MD.) 2023; 13:jkad172. [PMID: 37522561 PMCID: PMC10542173 DOI: 10.1093/g3journal/jkad172] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/25/2023] [Revised: 07/18/2023] [Accepted: 07/21/2023] [Indexed: 08/01/2023]
Abstract
Candida albicans is an efficient colonizer of human gastrointestinal tracts and skin and is an opportunistic pathogen. C. albicans exhibits morphological plasticity, and the ability to switch between yeast and filamentous morphologies is associated with virulence. One regulator of this switch is the quorum sensing molecule farnesol that is produced by C. albicans throughout growth. However, the synthesis, secretion, regulation, and turnover of farnesol are not fully understood. To address this, we used our improved farnesol assay to screen a transcription regulator knockout library for differences in farnesol accumulation in whole cultures, pellets, and supernatants. All screened mutants produced farnesol and they averaged 9.2× more farnesol in the pellet than the supernatant. Nineteen mutants had significant differences with ten mutants producing more farnesol than their SN152+ wild-type control strain while nine produced less. Seven mutants exhibited greater secretion of farnesol while two exhibited less. We examined the time course for farnesol accumulation in six mutants with the greatest accumulation differences and found that those differences persisted throughout growth and they were not time dependent. Significantly, two high-accumulating mutants did not exhibit the decay in farnesol levels during stationary phase characteristic of wild-type C. albicans, suggesting that a farnesol modification/degradation mechanism is absent in these mutants. Identifying these transcriptional regulators provides new insight into farnesol's physiological functions regarding cell cycle progression, white-opaque switching, yeast-mycelial dimorphism, and response to cellular stress.
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Affiliation(s)
- Daniel J Gutzmann
- School of Biological Sciences, University of Nebraska, Lincoln, NE 68588, USA
| | - Jaxon J Kramer
- School of Biological Sciences, University of Nebraska, Lincoln, NE 68588, USA
| | - Brigid M Toomey
- School of Biological Sciences, University of Nebraska, Lincoln, NE 68588, USA
| | - Cory H T Boone
- School of Biological Sciences, University of Nebraska, Lincoln, NE 68588, USA
| | - Audrey L Atkin
- School of Biological Sciences, University of Nebraska, Lincoln, NE 68588, USA
| | - Kenneth W Nickerson
- School of Biological Sciences, University of Nebraska, Lincoln, NE 68588, USA
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28
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Wakade RS, Krysan DJ. Comparative dynamics of gene expression during in vitro and in vivo Candida albicans filamentation. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.09.21.558874. [PMID: 37790536 PMCID: PMC10542175 DOI: 10.1101/2023.09.21.558874] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 10/05/2023]
Abstract
Candida albicans is one of them most common causes of fungal disease in humans and is a commensal member of the human microbiome. The ability of C. albicans to cause disease is tightly correlated with its ability to undergo a morphological transition from budding yeast to a filamentous form (hyphae and pseudohyphae). This morphological transition is accompanied by the induction of a set of well characterized hyphae-associated genes and transcriptional regulators. To date, the vast majority of data regarding this process has been based on in vitro studies of filamentation using a range of inducing conditions. Recently, we developed an in vivo imaging approach that allows the direct characterization of morphological transition during mammalian infection. Here, we couple this imaging assay with in vivo expression profiling to characterize the time course of in vivo filamentation and the accompanying changes in gene expression. We also compare in vivo observations to in vitro filamentation using a medium (RPMI 1640 tissue culture medium with 10% bovine calf serum) widely used to mimic host conditions. From these data, we make the following conclusions regarding in vivo and in vitro filamentation. First, the transcriptional programs regulating filamentation are rapidly induced in vitro and in vivo. Second, the tempo of filamentation in vivo is prolonged relative to in vitro filamentation and the period of high expression of genes associated with that process is also prolonged. Third, hyphae are adapting to changing infection environments after filamentation has reached steady-state.
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Affiliation(s)
- Rohan S. Wakade
- Department of Pediatrics, Carver College of Medicine, University of Iowa, Iowa City IA
| | - Damian J. Krysan
- Department of Pediatrics, Carver College of Medicine, University of Iowa, Iowa City IA
- Department of Molecular Physiology and Biophysics, Carver College of Medicine, University of Iowa, Iowa City IA
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29
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Murante D, Demers EG, Kurbessoian T, Ruzic M, Ashare A, Stajich JE, Hogan DA. Mrs4 loss of function in fungi during adaptation to the cystic fibrosis lung. mBio 2023; 14:e0117123. [PMID: 37432019 PMCID: PMC10470810 DOI: 10.1128/mbio.01171-23] [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: 05/23/2023] [Accepted: 05/25/2023] [Indexed: 07/12/2023] Open
Abstract
The genetic disease cystic fibrosis (CF) frequently leads to chronic lung infections by bacteria and fungi. We identified three individuals with CF with persistent lung infections dominated by Clavispora (Candida) lusitaniae. Whole-genome sequencing analysis of multiple isolates from each infection found evidence for selection for mutants in the gene MRS4 in all three distinct lung-associated populations. In each population, we found one or two unfixed, non-synonymous mutations in MRS4 relative to the reference allele found in multiple environmental and clinical isolates including the type strain. Genetic and phenotypic analyses found that all evolved alleles led to loss of function (LOF) of Mrs4, a mitochondrial iron transporter. RNA-seq analyses found that Mrs4 variants with decreased activity led to increased expression of genes involved in iron acquisition mechanisms in both low iron and replete iron conditions. Furthermore, surface iron reductase activity and intracellular iron were much higher in strains with Mrs4 LOF variants. Parallel studies found that a subpopulation of a CF-associated Exophiala dermatitidis infection also had a non-synonymous LOF mutation in MRS4. Together, these data suggest that MRS4 mutations may be beneficial during chronic CF lung infections in diverse fungi, perhaps, for the purposes of adaptation to an iron-restricted environment with chronic infections. IMPORTANCE The identification of MRS4 mutations in Clavispora (Candida) lusitaniae and Exophiala dermatitidis in individuals with cystic fibrosis (CF) highlights a possible adaptive mechanism for fungi during chronic CF lung infections. The findings of this study suggest that loss of function of the mitochondrial iron transporter Mrs4 can lead to increased activity of iron acquisition mechanisms, which may be advantageous for fungi in iron-restricted environments during chronic infections. This study provides valuable information for researchers working toward a better understanding of the pathogenesis of chronic lung infections and more effective therapies to treat them.
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Affiliation(s)
- Daniel Murante
- Department of Microbiology and Immunology, Geisel School of Medicine at Dartmouth, Hanover, New Hampshire, USA
| | - Elora G. Demers
- Department of Microbiology and Immunology, Geisel School of Medicine at Dartmouth, Hanover, New Hampshire, USA
| | - Tania Kurbessoian
- Department of Microbiology & Plant Pathology and Institute for Integrative Genome Biology, University of California-Riverside, Riverside, California, USA
| | - Marina Ruzic
- Department of Microbiology and Immunology, Geisel School of Medicine at Dartmouth, Hanover, New Hampshire, USA
| | - Alix Ashare
- Department of Microbiology and Immunology, Geisel School of Medicine at Dartmouth, Hanover, New Hampshire, USA
- Department of Medicine, Dartmouth Health, Lebanon, New Hampshire, USA
| | - Jason E. Stajich
- Department of Microbiology & Plant Pathology and Institute for Integrative Genome Biology, University of California-Riverside, Riverside, California, USA
| | - Deborah A. Hogan
- Department of Microbiology and Immunology, Geisel School of Medicine at Dartmouth, Hanover, New Hampshire, USA
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30
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Alabi PE, Gautier C, Murphy TP, Gu X, Lepas M, Aimanianda V, Sello JK, Ene IV. Small molecules restore azole activity against drug-tolerant and drug-resistant Candida isolates. mBio 2023; 14:e0047923. [PMID: 37326546 PMCID: PMC10470600 DOI: 10.1128/mbio.00479-23] [Citation(s) in RCA: 9] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2023] [Accepted: 04/13/2023] [Indexed: 06/17/2023] Open
Abstract
Each year, fungi cause more than 1.5 billion infections worldwide and have a devastating impact on human health, particularly in immunocompromised individuals or patients in intensive care units. The limited antifungal arsenal and emerging multidrug-resistant species necessitate the development of new therapies. One strategy for combating drug-resistant pathogens is the administration of molecules that restore fungal susceptibility to approved drugs. Accordingly, we carried out a screen to identify small molecules that could restore the susceptibility of pathogenic Candida species to azole antifungals. This screening effort led to the discovery of novel 1,4-benzodiazepines that restore fluconazole susceptibility in resistant isolates of Candida albicans, as evidenced by 100-1,000-fold potentiation of fluconazole activity. This potentiation effect was also observed in azole-tolerant strains of C. albicans and in other pathogenic Candida species. The 1,4-benzodiazepines selectively potentiated different azoles, but not other approved antifungals. A remarkable feature of the potentiation was that the combination of the compounds with fluconazole was fungicidal, whereas fluconazole alone is fungistatic. Interestingly, the potentiators were not toxic to C. albicans in the absence of fluconazole, but inhibited virulence-associated filamentation of the fungus. We found that the combination of the potentiators and fluconazole significantly enhanced host survival in a Galleria mellonella model of systemic fungal infection. Taken together, these observations validate a strategy wherein small molecules can restore the activity of highly used anti-infectives that have lost potency. IMPORTANCE In the last decade, we have been witnessing a higher incidence of fungal infections, due to an expansion of the fungal species capable of causing disease (e.g., Candida auris), as well as increased antifungal drug resistance. Among human fungal pathogens, Candida species are a leading cause of invasive infections and are associated with high mortality rates. Infections by these pathogens are commonly treated with azole antifungals, yet the expansion of drug-resistant isolates has reduced their clinical utility. In this work, we describe the discovery and characterization of small molecules that potentiate fluconazole and restore the susceptibility of azole-resistant and azole-tolerant Candida isolates. Interestingly, the potentiating 1,4-benzodiazepines were not toxic to fungal cells but inhibited their virulence-associated filamentous growth. Furthermore, combinations of the potentiators and fluconazole decreased fungal burdens and enhanced host survival in a Galleria mellonella model of systemic fungal infections. Accordingly, we propose the use of novel antifungal potentiators as a powerful strategy for addressing the growing resistance of fungi to clinically approved drugs.
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Affiliation(s)
- Philip E. Alabi
- Department of Chemistry, Brown University, Providence, Rhode Island, USA
- Department of Pharmaceutical Chemistry, University of California San Francisco, San Francisco, California, USA
| | - Cécile Gautier
- Institut Pasteur, Université Paris Cité, Fungal Heterogeneity Group, Paris, France
| | - Thomas P. Murphy
- Department of Molecular Microbiology and Immunology, Brown University, Providence, Rhode Island, USA
| | - Xilin Gu
- Department of Chemistry, Brown University, Providence, Rhode Island, USA
- Department of Pharmaceutical Chemistry, University of California San Francisco, San Francisco, California, USA
| | - Mathieu Lepas
- Institut Pasteur, Université Paris Cité, CNRS UMR2000, Molecular Mycology Unit, Paris, France
| | - Vishukumar Aimanianda
- Institut Pasteur, Université Paris Cité, CNRS UMR2000, Molecular Mycology Unit, Paris, France
| | - Jason K. Sello
- Department of Chemistry, Brown University, Providence, Rhode Island, USA
- Department of Pharmaceutical Chemistry, University of California San Francisco, San Francisco, California, USA
| | - Iuliana V. Ene
- Institut Pasteur, Université Paris Cité, Fungal Heterogeneity Group, Paris, France
- Department of Molecular Microbiology and Immunology, Brown University, Providence, Rhode Island, USA
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31
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Mao Y, Solis NV, Filler SG, Mitchell AP. Functional Dichotomy for a Hyphal Repressor in Candida albicans. mBio 2023; 14:e0013423. [PMID: 36883818 PMCID: PMC10127614 DOI: 10.1128/mbio.00134-23] [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: 01/15/2023] [Accepted: 02/20/2023] [Indexed: 03/09/2023] Open
Abstract
Nrg1 is a repressor of hypha formation and hypha-associated gene expression in the fungal pathogen Candida albicans. It has been well studied in the genetic background of the type strain SC5314. Here, we tested Nrg1 function in four other diverse clinical isolates through an analysis of nrg1Δ/Δ mutants, with SC5314 included as a control. In three strains, nrg1Δ/Δ mutants unexpectedly produced aberrant hyphae under inducing conditions, as assayed by microscopic observation and endothelial cell damage. The nrg1Δ/Δ mutant of strain P57055 had the most severe defect. We examined gene expression features under hypha-inducing conditions by RNA-sequencing (RNA-Seq) for the SC5314 and P57055 backgrounds. The SC5314 nrg1Δ/Δ mutant expressed six hypha-associated genes at reduced levels compared with wild-type SC5314. The P57055 nrg1Δ/Δ mutant expressed 17 hypha-associated genes at reduced levels compared with wild-type P57055, including IRF1, RAS2, and ECE1. These findings indicate that Nrg1 has a positive role in hypha-associated gene expression and that this role is magnified in strain P57055. Remarkably, the same hypha-associated genes affected by the nrg1Δ/Δ mutation in strain P57055 were also naturally expressed at lower levels in wild-type P57055 than those in wild-type SC5314. Our results suggest that strain P57055 is defective in a pathway that acts in parallel with Nrg1 to upregulate the expression of several hypha-associated genes. IMPORTANCE Hypha formation is a central virulence trait of the fungal pathogen Candida albicans. Control of hypha formation has been studied in detail in the type strain but not in other diverse C. albicans clinical isolates. Here, we show that the hyphal repressor Nrg1 has an unexpected positive role in hypha formation and hypha-associated gene expression, as revealed by the sensitized P57055 strain background. Our findings indicate that reliance on a single type strain limits understanding of gene function and illustrate that strain diversity is a valuable resource for C. albicans molecular genetic analysis.
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Affiliation(s)
- Yinhe Mao
- Department of Microbiology, University of Georgia, Athens, Georgia, USA
| | - Norma V. Solis
- Lundquist Institute for Biomedical Innovation at Harbor-UCLA Medical Center, Torrance, California, USA
| | - Scott G. Filler
- Lundquist Institute for Biomedical Innovation at Harbor-UCLA Medical Center, Torrance, California, USA
- David Geffen School of Medicine at UCLA, Los Angeles, California, USA
| | - Aaron P. Mitchell
- Department of Microbiology, University of Georgia, Athens, Georgia, USA
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Murante D, Demers EG, Kurbessoian T, Ruzic M, Ashare A, Stajich JE, Hogan DA. Mrs4 loss of function in fungi during adaptation to the cystic fibrosis lung. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.04.05.535776. [PMID: 37066389 PMCID: PMC10104081 DOI: 10.1101/2023.04.05.535776] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 04/27/2023]
Abstract
The genetic disease cystic fibrosis (CF) frequently leads to chronic lung infections by bacteria and fungi. We identified three individuals with CF with persistent lung infections dominated by Clavispora ( Candida ) lusitaniae . Whole genome sequencing analysis of multiple isolates from each infection found evidence for selection for mutants in the gene MRS4 in all three distinct lung-associated populations. In each population, we found one or two unfixed, non-synonymous mutations in MRS4 relative to the reference allele found in multiple environmental and clinical isolates including the type strain. Genetic and phenotypic analyses found that all evolved alleles led to loss of function of Mrs4, a mitochondrial iron transporter. RNA Seq analyses found that Mrs4 variants with decreased activity led to increased expression of genes involved in iron acquisition mechanisms in both low iron and replete iron conditions. Furthermore, surface iron reductase activity and intracellular iron was much higher in strains with Mrs4 loss of function variants. Parallel studies found that a subpopulation of a CF-associated Exophiala dermatiditis infection also had a non-synonymous loss of function mutation in MRS4. Together, these data suggest that MRS4 mutations may be beneficial during chronic CF lung infections in diverse fungi perhaps for the purposes of adaptation to an iron restricted environment with chronic infections.
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Affiliation(s)
- Daniel Murante
- Department of Microbiology and Immunology, Geisel School of Medicine at Dartmouth, Hanover, NH 03755
| | - Elora G. Demers
- Department of Microbiology and Immunology, Geisel School of Medicine at Dartmouth, Hanover, NH 03755
| | - Tania Kurbessoian
- Department of Microbiology & Plant Pathology and Institute for Integrative Genome Biology, University of California-Riverside, Riverside, California, USA
| | - Marina Ruzic
- Department of Microbiology and Immunology, Geisel School of Medicine at Dartmouth, Hanover, NH 03755
| | - Alix Ashare
- Department of Microbiology and Immunology, Geisel School of Medicine at Dartmouth, Hanover, NH 03755
- Department of Medicine, Dartmouth Health, Lebanon, NH, USA
| | - Jason E. Stajich
- Department of Microbiology & Plant Pathology and Institute for Integrative Genome Biology, University of California-Riverside, Riverside, California, USA
| | - Deborah A. Hogan
- Department of Microbiology and Immunology, Geisel School of Medicine at Dartmouth, Hanover, NH 03755
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Prasad P, Tippana M. Morphogenic plasticity: the pathogenic attribute of Candida albicans. Curr Genet 2023; 69:77-89. [PMID: 36947241 DOI: 10.1007/s00294-023-01263-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2022] [Revised: 02/10/2023] [Accepted: 02/20/2023] [Indexed: 03/23/2023]
Abstract
Candida albicans is a commensal organism of the human gastrointestinal tract and a prevalent opportunistic pathogen. It exhibits different morphogenic forms to survive in different host niches with distinct environmental conditions (pH, temperature, oxidative stress, nutrients, serum, chemicals, radiation, etc.) and genetic factors (transcription factors and genes). The different morphogenic forms of C. albicans are yeast, hyphal, pseudohyphal, white, opaque, and transient gray cells, planktonic and biofilm forms of cells. These forms differ in the parameters like cellular phenotype, colony morphology, adhesion to solid surfaces, gene expression profile, and the virulent traits. Each form is functionally distinct and responds discretely to the host immune system and antifungal drugs. Hence, morphogenic plasticity is the key to virulence. In this review, we address the characteristics, the pathogenic potential of the different morphogenic forms and the conditions required for morphogenic transitions.
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Affiliation(s)
- Priya Prasad
- Department of Biotechnology, National Institute of Technology Warangal, Warangal, Telangana, India.
| | - Meena Tippana
- Department of Biotechnology, National Institute of Technology Warangal, Warangal, Telangana, India
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Kakade P, Sircaik S, Maufrais C, Ene IV, Bennett RJ. Aneuploidy and gene dosage regulate filamentation and host colonization by Candida albicans. Proc Natl Acad Sci U S A 2023; 120:e2218163120. [PMID: 36893271 PMCID: PMC10089209 DOI: 10.1073/pnas.2218163120] [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: 10/24/2022] [Accepted: 02/02/2023] [Indexed: 03/11/2023] Open
Abstract
Aneuploidy is a frequent occurrence in fungal species where it can alter gene expression and promote adaptation to a variety of environmental cues. Multiple forms of aneuploidy have been observed in the opportunistic fungal pathogen Candida albicans, which is a common component of the human gut mycobiome but can escape this niche and cause life-threatening systemic disease. Using a barcode sequencing (Bar-seq) approach, we evaluated a set of diploid C. albicans strains and found that a strain carrying a third copy of chromosome (Chr) 7 was associated with increased fitness during both gastrointestinal (GI) colonization and systemic infection. Our analysis revealed that the presence of a Chr 7 trisomy resulted in decreased filamentation, both in vitro and during GI colonization, relative to isogenic euploid controls. A target gene approach demonstrated that NRG1, encoding a negative regulator of filamentation located on Chr 7, contributes to increased fitness of the aneuploid strain due to inhibition of filamentation in a gene dosage-dependent fashion. Together, these experiments establish how aneuploidy enables the reversible adaptation of C. albicans to its host via gene dosage-dependent regulation of morphology.
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Affiliation(s)
- Pallavi Kakade
- Molecular Microbiology and Immunology Department, Brown University, Providence, RI02912
| | - Shabnam Sircaik
- Molecular Microbiology and Immunology Department, Brown University, Providence, RI02912
| | - Corinne Maufrais
- Institut Pasteur Bioinformatic Hub, Université Paris Cité, Paris75015, France
- Institut Pasteur, Université Paris Cité, Fungal Heterogeneity Lab, Paris75015, France
| | - Iuliana V. Ene
- Institut Pasteur, Université Paris Cité, Fungal Heterogeneity Lab, Paris75015, France
| | - Richard J. Bennett
- Molecular Microbiology and Immunology Department, Brown University, Providence, RI02912
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Wakade RS, Ristow LC, Wellington M, Krysan DJ. Intravital imaging-based genetic screen reveals the transcriptional network governing Candida albicans filamentation during mammalian infection. eLife 2023; 12:e85114. [PMID: 36847358 PMCID: PMC9995110 DOI: 10.7554/elife.85114] [Citation(s) in RCA: 14] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2022] [Accepted: 02/26/2023] [Indexed: 03/01/2023] Open
Abstract
Candida albicans is one of the most common human fungal pathogens. C. albicans pathogenesis is tightly linked to its ability to under a morphogenetic transition from typically budding yeast to filamentous forms of hyphae and pseudohyphae. Filamentous morphogenesis is the most intensively studied C. albicans virulence traits; however, nearly all of these studies have been based on in vitro induction of filamentation. Using an intravital imaging assay of filamentation during mammalian (mouse) infection, we have screened a library of transcription factor mutants to identify those that modulate both the initiation and maintenance of filamentation in vivo. We coupled this initial screen with genetic interaction analysis and in vivo transcription profiling to characterize the transcription factor network governing filamentation in infected mammalian tissue. Three core positive (Efg1, Brg1, and Rob1) and two core negative regulators (Nrg1 and Tup1) of filament initiation were identified. No previous systematic analysis of genes affecting the elongation step has been reported and we found that large set of transcription factors affect filament elongation in vivo including four (Hms1, Lys14, War1, Dal81) with no effect on in vitro elongation. We also show that the gene targets of initiation and elongation regulators are distinct. Genetic interaction analysis of the core positive and negative regulators revealed that the master regulator Efg1 primarily functions to mediate relief of Nrg1 repression and is dispensable for expression of hypha-associated genes in vitro and in vivo. Thus, our analysis not only provide the first characterization of the transcriptional network governing C. albicans filamentation in vivo but also revealed a fundamentally new mode of function for Efg1, one of the most widely studied C. albicans transcription factors.
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Affiliation(s)
- Rohan S Wakade
- Department of Pediatrics, Carver College of Medicine, University of IowaIowa CityUnited States
| | - Laura C Ristow
- Department of Pediatrics, Carver College of Medicine, University of IowaIowa CityUnited States
| | - Melanie Wellington
- Department of Pediatrics, Carver College of Medicine, University of IowaIowa CityUnited States
| | - Damian J Krysan
- Department of Pediatrics, Carver College of Medicine, University of IowaIowa CityUnited States
- Departments of Microbiology and Immunology, Carver College of Medicine, University of IowaIowa CityUnited States
- Molecular Physiology and Biophysics, Carver College of Medicine, University of IowaIowa CityUnited States
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Garbe E, Thielemann N, Hohner S, Kumar A, Vylkova S, Kurzai O, Martin R. Functional analysis of the Candida albicans ECE1 Promoter. Microbiol Spectr 2023; 11:e0025323. [PMID: 36786567 PMCID: PMC10100963 DOI: 10.1128/spectrum.00253-23] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2023] [Accepted: 01/24/2023] [Indexed: 02/15/2023] Open
Abstract
The formation of hyphae is a key virulence attribute of Candida albicans as they are required for adhesion to and invasion of host cells, and ultimately deep-tissue dissemination. Hyphae also secrete the peptide toxin candidalysin, which is crucial for destruction of host cell membranes. The peptide is derived from a precursor protein encoded by the gene ECE1 which is strongly induced during hyphal growth. Previous studies revealed a very complex regulation of this gene involving several transcription factors. However, the promoter of the gene is still not characterized. Here, we present a functional analysis of the intergenic region upstream of the ECE1 gene. Rapid amplification of cDNA ends (RACE)-PCR was performed to identify the 5' untranslated region, which has a size of 49 bp regardless of the hyphae-inducing condition. By using green fluorescent protein (GFP) reporter constructs we further defined a minimal promoter length of 1,500 bp which was verified by RT-qPCR. Finally, we identified the TATA element required for the expression of the gene. It is located 106 to 109 bp upstream of the ECE1 start codon. Our results illustrate that despite a very short 5' UTR, a relatively long promoter is required to secure ECE1 transcription, indicating a complex regulatory machinery tightly controlling the expression of the gene. IMPORTANCE In recent years it was shown that secretion of the toxic peptide candidalysin from hyphae of the major human fungal pathogen Candida albicans contributes heavily to its virulence. The peptide is derived from a precursor protein which is encoded by the ECE1 gene whose transcription is known to be closely associated with formation of hyphae. Here, we used a GFP reporter system to determine the length of the ECE1 promoter and were able to show that it has a minimal size of 1,500 bp. Surprisingly, the gene has a very short 5' UTR of only 49 bp. In accordance with this, the TATA element required for transcription is located 106 to 109 bp upstream of the start codon. This indicates that ECE1 expression is controlled by a very long promoter allowing a complex network of transcription factors to contribute to the gene's regulation.
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Affiliation(s)
- Enrico Garbe
- Septomics Research Center, Friedrich Schiller University and Leibniz Institute for Natural Product Research and Infection Biology – Hans Knöll Institute, Jena, Germany
| | - Nadja Thielemann
- Institute for Hygiene and Microbiology, University of Würzburg, Würzburg, Germany
| | - Sina Hohner
- Institute for Hygiene and Microbiology, University of Würzburg, Würzburg, Germany
| | - Animesh Kumar
- Institute for Hygiene and Microbiology, University of Würzburg, Würzburg, Germany
| | - Slavena Vylkova
- Septomics Research Center, Friedrich Schiller University and Leibniz Institute for Natural Product Research and Infection Biology – Hans Knöll Institute, Jena, Germany
| | - Oliver Kurzai
- Institute for Hygiene and Microbiology, University of Würzburg, Würzburg, Germany
- Research Group Fungal Septomics, Leibniz Institute for Natural Product Research and Infection Biology – Hans Knöll Institute, Jena, Germany
- National Reference Center for Invasive Fungal Infections, Leibniz Institute for Natural Product Research and Infection Biology – Hans Knöll Institute, Jena, Germany
| | - Ronny Martin
- Institute for Hygiene and Microbiology, University of Würzburg, Würzburg, Germany
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Abid D, Brent MR. NetProphet 3: a machine learning framework for transcription factor network mapping and multi-omics integration. Bioinformatics 2023; 39:7000334. [PMID: 36692138 PMCID: PMC9912366 DOI: 10.1093/bioinformatics/btad038] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2022] [Revised: 01/11/2023] [Accepted: 01/18/2023] [Indexed: 01/25/2023] Open
Abstract
MOTIVATION Many methods have been proposed for mapping the targets of transcription factors (TFs) from gene expression data. It is known that combining outputs from multiple methods can improve performance. To date, outputs have been combined by using either simplistic formulae, such as geometric mean, or carefully hand-tuned formulae that may not generalize well to new inputs. Finally, the evaluation of accuracy has been challenging due to the lack of genome-scale, ground-truth networks. RESULTS We developed NetProphet3, which combines scores from multiple analyses automatically, using a tree boosting algorithm trained on TF binding location data. We also developed three independent, genome-scale evaluation metrics. By these metrics, NetProphet3 is more accurate than other commonly used packages, including NetProphet 2.0, when gene expression data from direct TF perturbations are available. Furthermore, its integration mode can forge a consensus network from gene expression data and TF binding location data. AVAILABILITY AND IMPLEMENTATION All data and code are available at https://zenodo.org/record/7504131#.Y7Wu3i-B2x8. SUPPLEMENTARY INFORMATION Supplementary data are available at Bioinformatics online.
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Affiliation(s)
- Dhoha Abid
- Center for Genome Sciences and Systems Biology, Washington University School of Medicine, St. Louis, MO 63110, USA.,Department of Computer Science and Engineering, Washington University, St. Louis, MO 63130, USA
| | - Michael R Brent
- Center for Genome Sciences and Systems Biology, Washington University School of Medicine, St. Louis, MO 63110, USA.,Department of Computer Science and Engineering, Washington University, St. Louis, MO 63130, USA.,Department of Genetics, Washington University School of Medicine, St. Louis, MO 63110, USA
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38
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Brown AJP. Fungal resilience and host-pathogen interactions: Future perspectives and opportunities. Parasite Immunol 2023; 45:e12946. [PMID: 35962618 PMCID: PMC10078341 DOI: 10.1111/pim.12946] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2022] [Revised: 08/08/2022] [Accepted: 08/10/2022] [Indexed: 01/31/2023]
Abstract
We are constantly exposed to the threat of fungal infection. The outcome-clearance, commensalism or infection-depends largely on the ability of our innate immune defences to clear infecting fungal cells versus the success of the fungus in mounting compensatory adaptive responses. As each seeks to gain advantage during these skirmishes, the interactions between host and fungal pathogen are complex and dynamic. Nevertheless, simply compromising the physiological robustness of fungal pathogens reduces their ability to evade antifungal immunity, their virulence, and their tolerance against antifungal therapy. In this article I argue that this physiological robustness is based on a 'Resilience Network' which mechanistically links and controls fungal growth, metabolism, stress resistance and drug tolerance. The elasticity of this network probably underlies the phenotypic variability of fungal isolates and the heterogeneity of individual cells within clonal populations. Consequently, I suggest that the definition of the fungal Resilience Network represents an important goal for the future which offers the clear potential to reveal drug targets that compromise drug tolerance and synergise with current antifungal therapies.
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Affiliation(s)
- Alistair J P Brown
- Medical Research Council Centre for Medical Mycology at the University of Exeter, Exeter, UK
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39
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Design, Synthesis and Structure-Activity Relationship Studies of Nicotinamide Derivatives as Potent Antifungal Agents by Disrupting Cell Wall. Molecules 2023; 28:molecules28031135. [PMID: 36770802 PMCID: PMC9919825 DOI: 10.3390/molecules28031135] [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: 12/14/2022] [Revised: 01/16/2023] [Accepted: 01/20/2023] [Indexed: 01/25/2023] Open
Abstract
Fungal infections pose a serious challenge to human health due to the limited paucity of antifungal treatments. Starting as a hit compound screened from our compound library, a series of nicotinamide derivatives have been successfully synthesized via a facile one-step coupling reaction of aromatic carboxylic acid and amine. The synthesized compounds were evaluated for their antifungal activity against Candida albicans SC5314. Among the 37 nicotinamide derivatives screened, compound 16g was found to be the most active against C. albicans SC5314, with an MIC value of 0.25 μg/mL and without significant cytotoxicity. The rudimentary structure-activity relationships study revealed that the position of the amino and isopropyl groups of 16g was critical for its antifungal activity. In particular, compound 16g showed potent activity against six fluconazole-resistant C. albicans strains with MIC values ranging from 0.125-1 μg/mL and showed moderate activity against the other seven species of Candida, three strains of Cryptococcus neoformans, and three strains of Trichophyton. Furthermore, compound 16g showed fungicidal, anti-hyphal, and anti-biofilm activities in vitro, which were related to its ability to disrupt the cell wall of C. albicans. Taken together, 16g is a promising compound that is fungal-specific by targeting the cell wall and could be used as a lead compound for further investigation.
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40
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Mariscal J, Thomas DP, Cleary IA. Examining the effects of BRG1 over-expression on Candida albicans strains growing as pseudohyphae. Folia Microbiol (Praha) 2023:10.1007/s12223-023-01034-2. [PMID: 36656405 DOI: 10.1007/s12223-023-01034-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2022] [Accepted: 01/12/2023] [Indexed: 01/20/2023]
Abstract
The pathogen Candida albicans is pleiomorphic and grows in yeast and filamentous forms but the relationship between the regulation of different filamentous forms is unclear. BRG1 encodes a DNA binding protein which is an important regulator of morphology. Mutants lacking BRG1 grow as yeast under all conditions tested and over-expressing BRG1 drives hyphal growth even in the absence of inducing signals. A number of genetic mutants in repressors of filamentation form pseudohyphae under yeast conditions and some of these mutants can form hyphae under hypha-inducing conditions. This study examines the position of BRG1 in the regulatory networks that govern filamentation by examining the effect of over-expressing BRG1 in pseudohyphal mutants.
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Affiliation(s)
- Joseph Mariscal
- Department of Biomedical Sciences, Grand Valley State University, One Campus Drive, Allendale, MI, 49401, USA
| | - Derek P Thomas
- Department of Biomedical Sciences, Grand Valley State University, One Campus Drive, Allendale, MI, 49401, USA
| | - Ian A Cleary
- Department of Biomedical Sciences, Grand Valley State University, One Campus Drive, Allendale, MI, 49401, USA.
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41
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Mao YS, Chen JW, Wang ZH, Xu MY, Gao XD. Roles of the transcriptional regulators Fts1, YlNrg1, YlTup1, and YlSsn6 in the repression of the yeast-to-filament transition in the dimorphic yeast Yarrowia lipolytica. Mol Microbiol 2023; 119:126-142. [PMID: 36537557 DOI: 10.1111/mmi.15017] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2022] [Revised: 12/04/2022] [Accepted: 12/15/2022] [Indexed: 12/24/2022]
Abstract
In dimorphic fungi, the yeast-to-filament transition critical for cell survival under nutrient starvation is controlled by both activators and repressors. However, very few filamentation repressors are known. Here we report that, in the dimorphic yeast Yarrowia lipolytica, the conserved transcription factor YlNrg1 plays a minor role whereas Fts1, a newly identified Zn(II)2 Cys6 zinc cluster transcription factor, plays a key role in filamentation repression. FTS1 deletion caused hyperfilamentation whereas Fts1 overexpression drastically reduced filamentation. The expression of FTS1 is downregulated substantially during the yeast-to-filament transition. Transcriptome sequencing revealed that Fts1 represses 401 genes, including the filamentation-activating transcription factor genes MHY1, YlAZF1, and YlWOR4 and key cell wall protein genes. Tup1-Ssn6, a general transcriptional corepressor, is involved in the repression of many cellular functions in fungi. We show that both YlTup1 and YlSsn6 strongly repress filamentation in Y. lipolytica. YlTup1 and YlSsn6 together repress 1383 genes, including a large number of transcription factor and cell wall protein genes, which overlap substantially with Fts1-repressed genes. Fts1 interacts with both YlTup1 and YlSsn6, and LexA-Fts1 fusion represses a lexAop-promoter-lacZ reporter in a Tup1-Ssn6-dependent manner. Our findings suggest that Fts1 functions as a transcriptional repressor, directing the repression of target genes through the Tup1-Ssn6 corepressor.
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Affiliation(s)
- Yi-Sheng Mao
- Hubei Key Laboratory of Cell Homeostasis, College of Life Sciences, Wuhan University, Wuhan, China
| | - Jia-Wen Chen
- Hubei Key Laboratory of Cell Homeostasis, College of Life Sciences, Wuhan University, Wuhan, China
| | - Zhen-Hua Wang
- Hubei Key Laboratory of Cell Homeostasis, College of Life Sciences, Wuhan University, Wuhan, China
| | - Meng-Yang Xu
- Hubei Key Laboratory of Cell Homeostasis, College of Life Sciences, Wuhan University, Wuhan, China
| | - Xiang-Dong Gao
- Hubei Key Laboratory of Cell Homeostasis, College of Life Sciences, Wuhan University, Wuhan, China
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Patel SK, Sahu SR, Utkalaja BG, Bose S, Acharya N. Pol32, an accessory subunit of DNA polymerase delta, plays an essential role in genome stability and pathogenesis of Candida albicans. Gut Microbes 2023; 15:2163840. [PMID: 36601868 PMCID: PMC9828637 DOI: 10.1080/19490976.2022.2163840] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/06/2023] Open
Abstract
Candida albicans is a pathobiont that inflicts serious bloodstream fungal infections in individuals with compromised immunity and gut dysbiosis. Genomic diversity in the form of copy number alteration, ploidy variation, and loss of heterozygosity as an adaptive mechanism to adverse environments is frequently observed in C. albicans. Such genomic variations also confer a varied degree of fungal virulence and drug resistance, yet the factors propelling these are not completely understood. DNA polymerase delta (Polδ) is an essential replicative DNA polymerase in the eukaryotic cell and is yet to be characterized in C. albicans. Therefore, this study was designed to gain insights into the role of Polδ, especially its non-essential subunit Pol32, in the genome plasticity and life cycle of C. albicans. PCNA, the DNA clamp, recruits Polδ to the replication fork for processive DNA replication. Unlike in Saccharomyces cerevisiae, the PCNA interaction protein (PIP) motif of CaPol32 is critical for Polδ's activity during DNA replication. Our comparative genetic analyses and whole-genome sequencing of POL32 proficient and deficient C. albicans cells revealed a critical role of Pol32 in DNA replication, cell cycle progression, and genome stability as SNPs, indels, and repeat variations were largely accumulated in pol32 null strain. The loss of pol32 in C. albicans conferred cell wall deformity; Hsp90 mediated azoles resistance, biofilm development, and a complete attenuation of virulence in an animal model of systemic candidiasis. Thus, although Pol32 is dispensable for cell survival, its function is essential for C. albicans pathogenesis; and we discuss its translational implications in antifungal drugs and whole-cell vaccine development.
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Affiliation(s)
- Shraddheya Kumar Patel
- Laboratory of Genomic Instability and Diseases, Department of Infectious Disease Biology, Institute of Life Sciences, Bhubaneswar, India,Regional center of Biotechnology, Faridabad, India
| | - Satya Ranjan Sahu
- Laboratory of Genomic Instability and Diseases, Department of Infectious Disease Biology, Institute of Life Sciences, Bhubaneswar, India,Regional center of Biotechnology, Faridabad, India
| | - Bhabasha Gyanadeep Utkalaja
- Laboratory of Genomic Instability and Diseases, Department of Infectious Disease Biology, Institute of Life Sciences, Bhubaneswar, India,Regional center of Biotechnology, Faridabad, India
| | - Swagata Bose
- Laboratory of Genomic Instability and Diseases, Department of Infectious Disease Biology, Institute of Life Sciences, Bhubaneswar, India,School of Biotechnology, Kalinga Institute of Industrial Technology, Bhubaneswar, India
| | - Narottam Acharya
- Laboratory of Genomic Instability and Diseases, Department of Infectious Disease Biology, Institute of Life Sciences, Bhubaneswar, India,CONTACT Narottam Acharya ; Laboratory of Genomic Instability and Diseases, Department of Infectious Disease Biology, Institute of Life Sciences, Bhubaneswar751023, India
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43
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The Zinc Finger Transcription Factor Fts2 Represses the Yeast-to-Filament Transition in the Dimorphic Yeast Yarrowia lipolytica. mSphere 2022; 7:e0045022. [PMID: 36409080 PMCID: PMC9769893 DOI: 10.1128/msphere.00450-22] [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] [Indexed: 11/23/2022] Open
Abstract
The yeast-to-filament transition is an important cellular response to environmental stimulations in dimorphic fungi. In addition to activators, there are repressors in the cells to prevent filament formation, which is important to keep the cells in the yeast form when filamentation is not necessary. However, very few repressors of filamentation are known so far. Here, we identify a novel repressor of filamentation in the dimorphic yeast Yarrowia lipolytica, Fts2, which is a C2H2-type zinc finger transcription factor. We show that fts2Δ cells exhibited increased filamentation under mild filament-inducing conditions and formed filaments under non-filament-inducing conditions. We also show that Fts2 interacts with YlSsn6, component of the Tup1-Ssn6 transcriptional corepressor, and Fts2-LexA represses a lexAop-PYlACT1-lacZ reporter in a Tup1-Ssn6-dependent manner, suggesting that Fts2 has transcriptional repressor activity and represses gene expression via Tup1-Ssn6. In addition, we show that Fts2 represses a large number of cell wall protein genes and transcription factor genes, some of which are implicated in the filamentation response. Interestingly, about two-thirds of Fts2-repressed genes are also repressed by Tup1-Ssn6, suggesting that Fts2 may repress the bulk of its target genes via Tup1-Ssn6. Lastly, we show that Fts2 expression is downregulated in response to alkaline pH and the relief of negative control by Fts2 facilitates the induction of filamentation by alkaline pH. IMPORTANCE The repressors of filamentation are important negative regulators of the yeast-to-filament transition. However, except in Candida albicans, very few repressors of filamentation are known in dimorphic fungi. More importantly, how they repress filamentation is often not clear. In this paper, we report a novel repressor of filamentation in Y. lipolytica. Fts2 is not closely related in amino acid sequence to CaNrg1 and Rfg1, two major repressors of filamentation in C. albicans, yet it represses gene expression via the transcriptional corepressor Tup1-Ssn6, similar to CaNrg1 and Rfg1. Using transcriptome sequencing, we determined the whole set of genes regulated by Fts2 and identified the major targets of Fts2 repression, which provide clues to the mechanism by which Fts2 represses filamentation. Our results have important implications for understanding the negative control of the yeast-to-filament transition in dimorphic fungi.
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Zeng G, Neo SP, Pang LM, Gao J, Chong SC, Gunaratne J, Wang Y. Comprehensive Interactome Analysis for the Sole Adenylyl Cyclase Cyr1 of Candida albicans. Microbiol Spectr 2022; 10:e0393422. [PMID: 36314909 PMCID: PMC9769623 DOI: 10.1128/spectrum.03934-22] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2022] [Accepted: 10/06/2022] [Indexed: 11/06/2022] Open
Abstract
Cyr1, the sole adenylyl cyclase of the fungal pathogen Candida albicans, is a central component of the cAMP/protein kinase A signaling pathway that controls the yeast-to-hypha transition. Cyr1 is a multivalent sensor and integrator of various external and internal signals. To better understand how these signals are relayed to Cyr1 to regulate its activity, we sought to establish the interactome of Cyr1 by using stable isotope labeling by amino acids in cell culture (SILAC)-based quantitative proteomics to identify the proteins that coimmunoprecipitated with Cyr1. The method identified 36 proteins as candidates for authentic Cyr1-interacting partners, together with two known Cyr1-binding proteins, Cap1 and Act1. Fourteen identified proteins belonged to three functional groups, including actin regulation, cell wall components, and mitochondrial activities, that are known to play important roles in cell morphogenesis. To validate the proteomics data, we used biochemical and genetic methods to characterize two cell wall-related proteins, Mp65 and Sln1. First, coimmunoprecipitation confirmed their physical association with Cyr1. Second, deleting either MP65 or SLN1 resulted in severe defects in filamentation on serum plates. This study establishes the first Cyr1 interactome and uncovers a potential role for cell wall proteins in directly regulating Cyr1 activity to determine growth forms in C. albicans. IMPORTANCE A critical virulence trait of the human fungal pathogen Candida albicans is its ability to undergo the yeast-to-hypha transition in response to diverse environmental and cellular stimuli. Previous studies suggested that the sole adenylyl cyclase of C. albicans, Cyr1, is a multivalent signal sensor and integrator synthesizing cAMP to activate the downstream hypha-promoting events through the cAMP/protein kinase A pathway. To fully understand how Cyr1 senses and processes multiple stimuli to generate appropriate signal outputs, it was necessary to identify and characterize Cyr1-interacting partners. This study employed SILAC-based quantitative proteomic approaches and identified 36 Cyr1-associated proteins, many having functions associated with hyphal morphogenesis. Coimmunoprecipitation verified two cell surface proteins, Mp65 and Sln1. Furthermore, genetic and phenotypic analyses demonstrated the cAMP-dependent roles of these two proteins in determining hyphal growth. Our study establishes the first Cyr1 interactome and uncovers new Cyr1 regulators that mediate cell surface signals to influence the growth mode of C. albicans.
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Affiliation(s)
| | - Suat Peng Neo
- Quantitative Proteomics Group, Institute of Molecular and Cell Biology, Singapore
| | | | | | | | - Jayantha Gunaratne
- Quantitative Proteomics Group, Institute of Molecular and Cell Biology, Singapore
- Department of Anatomy, Yong Loo Lin School of Medicine, National University of Singapore, Singapore
| | - Yue Wang
- Infectious Diseases Labs, Singapore
- Department of Biochemistry, Yong Loo Lin School of Medicine, National University of Singapore, Singapore
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Lopes JP, Lionakis MS. Pathogenesis and virulence of Candida albicans. Virulence 2022; 13:89-121. [PMID: 34964702 PMCID: PMC9728475 DOI: 10.1080/21505594.2021.2019950] [Citation(s) in RCA: 128] [Impact Index Per Article: 64.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2021] [Revised: 12/08/2021] [Accepted: 12/14/2021] [Indexed: 12/18/2022] Open
Abstract
Candida albicans is a commensal yeast fungus of the human oral, gastrointestinal, and genital mucosal surfaces, and skin. Antibiotic-induced dysbiosis, iatrogenic immunosuppression, and/or medical interventions that impair the integrity of the mucocutaneous barrier and/or perturb protective host defense mechanisms enable C. albicans to become an opportunistic pathogen and cause debilitating mucocutaneous disease and/or life-threatening systemic infections. In this review, we synthesize our current knowledge of the tissue-specific determinants of C. albicans pathogenicity and host immune defense mechanisms.
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Affiliation(s)
- José Pedro Lopes
- From the Fungal Pathogenesis Section, Laboratory of Clinical Immunology and Microbiology (LCIM), National Institute of Allergy and Infectious Diseases (NIAID), Bethesda, MD, USA
| | - Michail S. Lionakis
- From the Fungal Pathogenesis Section, Laboratory of Clinical Immunology and Microbiology (LCIM), National Institute of Allergy and Infectious Diseases (NIAID), Bethesda, MD, USA
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Hossain S, Robbins N, Cowen LE. The GARP complex is required for filamentation in Candida albicans. Genetics 2022; 222:iyac152. [PMID: 36226807 PMCID: PMC9713427 DOI: 10.1093/genetics/iyac152] [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: 08/10/2022] [Accepted: 09/29/2022] [Indexed: 12/13/2022] Open
Abstract
Candida albicans is an opportunistic fungal pathogen that causes superficial infections in immunocompetent individuals, as well as life-threatening systemic disease in immunocompromised patients. A key virulence trait of this pathogen is its ability to transition between yeast and filamentous morphologies. A functional genomic screen to identify novel regulators of filamentation previously revealed VPS53 as being important for morphogenesis. Vps53 belongs to the Golgi-associated retrograde protein (GARP) complex, which mediates retrograde trafficking from the endosome to the trans-Golgi network. Here, we explored the role of the entire GARP complex in regulating morphogenesis. Deletion of any of the four genes encoding GARP complex subunits severely impaired filamentation in response to diverse filament-inducing cues, including upon internalization by macrophages. Genetic pathway analysis revealed that while hyperactivation of protein kinase A (PKA) signaling is insufficient to drive filamentation in GARP complex mutants, these strains are capable of filamentation upon overexpression of transcriptional activators or upon deletion of transcriptional repressors of hyphal morphogenesis. Finally, compromise of the GARP complex induced lipotoxicity, and pharmacological inhibition of sphingolipid biosynthesis phenocopied genetic compromise of the GARP complex by impairing filamentation. Together, this work identifies the GARP complex as an important mediator of filamentation in response to multiple inducing cues, maps genetic circuitry important for filamentation upon compromise of GARP function, and supports a model whereby GARP deficiency impairs lipid homeostasis, which is important for supporting filamentous growth in C. albicans.
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Affiliation(s)
- Saif Hossain
- Department of Molecular Genetics, University of Toronto, Toronto, ON, Canada
| | - Nicole Robbins
- Department of Molecular Genetics, University of Toronto, Toronto, ON, Canada
| | - Leah E Cowen
- Department of Molecular Genetics, University of Toronto, Toronto, ON, Canada
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Williams S, Cleary I, Thomas D. Anaerobic conditions are a major influence on Candida albicans chlamydospore formation. Folia Microbiol (Praha) 2022; 68:321-324. [PMID: 36418845 DOI: 10.1007/s12223-022-01018-8] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2022] [Accepted: 11/13/2022] [Indexed: 11/25/2022]
Abstract
Candidiasis now represents the fourth most frequent nosocomial infection both in the USA and worldwide. Candida albicans is an increasingly common threat to human health as a consequence of AIDS, steroid therapy, organ and tissue transplantation, cancer therapy, broad-spectrum antibiotics, and other immune defects. Unfortunately, these infections carry unacceptably high morbidity, mortality rates and important economic repercussions (estimated total direct cost of approximately 2 billion dollars in 1998 in US hospitals alone). This pathogen can grow both in yeast and filamentous forms and the pathogenic potential of C. albicans is intimately related to certain key processes including filamentation. Chlamydospores are considered to be a dormant form of C. albicans that remain understudied. Chlamydospores have been widely used as a diagnostic tool to separate C. albicans and C. dubliniensis from other Candida species. More recently, media have been developed that use chlamydopsore formation to separate C. albicans and C. dubliniensis from each other. Chlamydospore formation can be stimulated by hypoxic conditions but only on limited specific media types. Here, we show that anaerobic conditions are enough to drive chlamydospore formation in C. albicans on the surface of nutrient-rich agar.
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Affiliation(s)
- Shannon Williams
- Department of Biomedical Sciences, Grand Valley State University, 1 Campus Drive, Allendale, MI, 49401-9401, USA
| | - Ian Cleary
- Department of Biomedical Sciences, Grand Valley State University, 1 Campus Drive, Allendale, MI, 49401-9401, USA
| | - Derek Thomas
- Department of Biomedical Sciences, Grand Valley State University, 1 Campus Drive, Allendale, MI, 49401-9401, USA.
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The Antimicrobial Peptide AMP-17 Derived from Musca domestica Inhibits Biofilm Formation and Eradicates Mature Biofilm in Candida albicans. Antibiotics (Basel) 2022; 11:antibiotics11111474. [PMID: 36358129 PMCID: PMC9686669 DOI: 10.3390/antibiotics11111474] [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: 09/26/2022] [Revised: 10/17/2022] [Accepted: 10/23/2022] [Indexed: 12/02/2022] Open
Abstract
The biofilm formation of C. albicans represents a major virulence factor during candidiasis. Biofilm-mediated drug resistance has necessitated the search for a new antifungal treatment strategy. In our previous study, a novel antimicrobial peptide named AMP-17 derived from Musca domestica was confirmed to have significant antifungal activity and suppress hyphal growth greatly in C. albicans. In the current work, we aimed to investigate the antibiofilm property of AMP-17 in C. albicans and explore the underlying mechanism. An antifungal susceptibility assay showed that AMP-17 exerted a strong inhibitory efficacy on both biofilm formation and preformed biofilms in C. albicans. Furthermore, AMP-17 was found to block the yeast-to-hypha transition and inhibit the adhesion of biofilm cells with a reduction in cellular surface hydrophobicity. A morphological analysis revealed that AMP-17 indeed suppressed typical biofilm formation and damaged the structures of the preformed biofilm. The RNA-seq showed that the MAPK pathway, biosynthesis of antibiotics, and essential components of the cell were mainly enriched in the biofilm-forming stage, while the citrate cycle (TCA cycle), phenylamine metabolism, and propanoate metabolism were enriched after the biofilm matured. Moreover, the co-expressed DEGs in the two pairwise comparisons highlighted the terms of transmembrane transporter activity, regulation of filamentation, and biofilm formation as important roles in the antibiofilm effect of AMP-17. Additionally, qRT-PCR confirmed that the level of the genes involved in cell adhesion, filamentous growth, MAPK, biofilm matrix, and cell dispersal was correspondingly altered after AMP-17 treatment. Overall, our findings reveal the underlying antibiofilm mechanisms of AMPs in C. albicans, providing an interesting perspective for the development of effective antifungal agents with antibiofilm efficacy in Candida spp.
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Hans S, Fatima Z, Ahmad A, Hameed S. Magnesium impairs Candida albicans immune evasion by reduced hyphal damage, enhanced β-glucan exposure and altered vacuole homeostasis. PLoS One 2022; 17:e0270676. [PMID: 35834579 PMCID: PMC9282612 DOI: 10.1371/journal.pone.0270676] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2022] [Accepted: 06/14/2022] [Indexed: 11/18/2022] Open
Abstract
With a limited arsenal of available antifungal drugs and drug-resistance emergence, strategies that seek to reduce Candida immune evasion and virulence could be a promising alternative option. Harnessing metal homeostasis against C. albicans has gained wide prominence nowadays as a feasible antifungal strategy. Herein, the effect of magnesium (Mg) deprivation on the immune evasion mechanisms of C. albicans is demonstrated. We studied host pathogen interaction by using the THP-1 cell line model and explored the avenue that macrophage-mediated killing was enhanced under Mg deprivation, leading to altered cytokine (TNFα, IL-6 and IL10) production and reduced pyroptosis. Insights into the mechanisms revealed that hyphal damage inside the macrophage was diminished under Mg deprivation. Additionally, Mg deprivation led to cell wall remodelling; leading to enhanced β-1,3-glucan exposure, crucial for immune recognition, along with concomitant alterations in chitin and mannan levels. Furthermore, vacuole homeostasis was disrupted under Mg deprivation, as revealed by abrogated morphology and defective acidification of the vacuole lumen. Together, we demonstrated that Mg deprivation affected immune evasion mechanisms by: reduced hyphal damage, enhanced β-1,3-glucan exposure and altered vacuole functioning. The study establishes that Mg availability is indispensable for successful C. albicans immune evasion and specific Mg dependent pathways could be targeted for therapy.
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Affiliation(s)
- Sandeep Hans
- Amity Institute of Biotechnology, Amity University Haryana, Manesar, Gurugram, India
| | - Zeeshan Fatima
- Amity Institute of Biotechnology, Amity University Haryana, Manesar, Gurugram, India
- * E-mail: (ZF); (SH)
| | - Aijaz Ahmad
- Clinical Microbiology and Infectious Diseases, Faculty of Health Sciences, School of Pathology, University of the Witwatersrand, Johannesburg, South Africa
- Infection Control, National Health Laboratory Service, Charlotte Maxeke Johannesburg Academic Hospital, Johannesburg, South Africa
| | - Saif Hameed
- Amity Institute of Biotechnology, Amity University Haryana, Manesar, Gurugram, India
- * E-mail: (ZF); (SH)
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Häring M, Amann V, Kissmann AK, Herberger T, Synatschke C, Kirsch-Pietz N, Perez-Erviti JA, Otero-Gonzalez AJ, Morales-Vicente F, Andersson J, Weil T, Stenger S, Rodríguez A, Ständker L, Rosenau F. Combination of Six Individual Derivatives of the Pom-1 Antibiofilm Peptide Doubles Their Efficacy against Invasive and Multi-Resistant Clinical Isolates of the Pathogenic Yeast Candida albicans. Pharmaceutics 2022; 14:pharmaceutics14071332. [PMID: 35890228 PMCID: PMC9319270 DOI: 10.3390/pharmaceutics14071332] [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: 05/17/2022] [Revised: 06/14/2022] [Accepted: 06/21/2022] [Indexed: 11/17/2022] Open
Abstract
In previous studies, derivatives of the peptide Pom-1, which was originally extracted from the freshwater mollusk Pomacea poeyana, showed an exceptional ability to specifically inhibit biofilm formation of the laboratory strain ATCC 90028 as a model strain of the pathogenic yeast Candida albicans. In follow-up, here, we demonstrate that the derivatives Pom-1A to Pom-1F are also active against biofilms of invasive clinical C. albicans isolates, including strains resistant against fluconazole and/or amphotericin B. However, efficacy varied strongly between the isolates, as indicated by large deviations in the experiments. This lack of robustness could be efficiently bypassed by using mixtures of all peptides. These mixed peptide preparations were active against biofilm formation of all the isolates with uniform efficacies, and the total peptide concentration could be halved compared to the original MIC of the individual peptides (2.5 µg/mL). Moreover, mixing the individual peptides restored the antifungal effect of fluconazole against fluconazole-resistant isolates even at 50% of the standard therapeutic concentration. Without having elucidated the reason for these synergistic effects of the peptides yet, both the gain of efficacy and the considerable increase in efficiency by combining the peptides indicate that Pom-1 and its derivatives in suitable formulations may play an important role as new antibiofilm antimycotics in the fight against invasive clinical infections with (multi-) resistant C. albicans.
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Affiliation(s)
- Michelle Häring
- Institute of Pharmaceutical Biotechnology, Ulm University, Albert-Einstein-Allee 11, 89081 Ulm, Germany; (M.H.); (V.A.)
| | - Valerie Amann
- Institute of Pharmaceutical Biotechnology, Ulm University, Albert-Einstein-Allee 11, 89081 Ulm, Germany; (M.H.); (V.A.)
| | - Ann-Kathrin Kissmann
- Institute of Pharmaceutical Biotechnology, Ulm University, Albert-Einstein-Allee 11, 89081 Ulm, Germany; (M.H.); (V.A.)
- Max Planck Institute for Polymer Research Mainz, Ackermannweg 10, 55128 Mainz, Germany; (T.H.); (C.S.); (N.K.-P.); (T.W.)
- Correspondence: (A.-K.K.); (F.R.)
| | - Tilmann Herberger
- Max Planck Institute for Polymer Research Mainz, Ackermannweg 10, 55128 Mainz, Germany; (T.H.); (C.S.); (N.K.-P.); (T.W.)
| | - Christopher Synatschke
- Max Planck Institute for Polymer Research Mainz, Ackermannweg 10, 55128 Mainz, Germany; (T.H.); (C.S.); (N.K.-P.); (T.W.)
| | - Nicole Kirsch-Pietz
- Max Planck Institute for Polymer Research Mainz, Ackermannweg 10, 55128 Mainz, Germany; (T.H.); (C.S.); (N.K.-P.); (T.W.)
| | - Julio A. Perez-Erviti
- Center for Protein Studies, Faculty of Biology, University of Havana, 25 Street, Havana 10400, Cuba; (J.A.P.-E.); (A.J.O.-G.)
| | - Anselmo J. Otero-Gonzalez
- Center for Protein Studies, Faculty of Biology, University of Havana, 25 Street, Havana 10400, Cuba; (J.A.P.-E.); (A.J.O.-G.)
| | - Fidel Morales-Vicente
- Synthetic Peptides Group, Center for Genetic Engineering and Biotechnology, Havana 10600, Cuba;
| | - Jakob Andersson
- AIT Austrian Institute of Technology GmbH, Giefinggasse 4, 1210 Vienna, Austria;
| | - Tanja Weil
- Max Planck Institute for Polymer Research Mainz, Ackermannweg 10, 55128 Mainz, Germany; (T.H.); (C.S.); (N.K.-P.); (T.W.)
| | - Steffen Stenger
- Institute for Medical Microbiology and Hygiene, University Hospital Ulm, 89081 Ulm, Germany;
| | - Armando Rodríguez
- Core Facility for Functional Peptidomics, Ulm Peptide Pharmaceuticals (U-PEP), Faculty of Medicine, Ulm University, 89081 Ulm, Germany; (A.R.); (L.S.)
- Core Unit of Mass Spectrometry and Proteomics, Faculty of Medicine, Ulm University, 89081 Ulm, Germany
| | - Ludger Ständker
- Core Facility for Functional Peptidomics, Ulm Peptide Pharmaceuticals (U-PEP), Faculty of Medicine, Ulm University, 89081 Ulm, Germany; (A.R.); (L.S.)
| | - Frank Rosenau
- Institute of Pharmaceutical Biotechnology, Ulm University, Albert-Einstein-Allee 11, 89081 Ulm, Germany; (M.H.); (V.A.)
- Max Planck Institute for Polymer Research Mainz, Ackermannweg 10, 55128 Mainz, Germany; (T.H.); (C.S.); (N.K.-P.); (T.W.)
- Correspondence: (A.-K.K.); (F.R.)
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