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Kumar D, Kumar A. Molecular Determinants Involved in Candida albicans Biofilm Formation and Regulation. Mol Biotechnol 2024; 66:1640-1659. [PMID: 37410258 DOI: 10.1007/s12033-023-00796-x] [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: 03/30/2023] [Accepted: 06/14/2023] [Indexed: 07/07/2023]
Abstract
Candida albicans is known for its pathogenicity, although it lives within the human body as a commensal member. The commensal nature of C. albicans is well controlled and regulated by the host's immune system as they live in the harmonized microenvironment. However, the development of certain unusual microhabitat conditions (change in pH, co-inhabiting microorganisms' population ratio, debilitated host-immune system) pokes this commensal fungus to transform into a pathogen in such a way that it starts to propagate very rapidly and tries to breach the epithelial barrier to enter the host's systemic circulations. In addition, Candida is infamous as a major nosocomial (hospital-acquired infection) agent because it enters the human body through venous catheters or medical prostheses. The hysterical mode of C. albicans growth builds its microcolony or biofilm, which is pathogenic for the host. Biofilms propose additional resistance mechanisms from host immunity or extracellular chemicals to aid their survival. Differential gene expressions and regulations within the biofilms cause altered morphology and metabolism. The genes associated with adhesiveness, hyphal/pseudo-hyphal growth, persister cell transformation, and biofilm formation by C. albicans are controlled by myriads of cell-signaling regulators. These genes' transcription is controlled by different molecular determinants like transcription factors and regulators. Therefore, this review has focused discussion on host-immune-sensing molecular determinants of Candida during biofilm formation, regulatory descriptors (secondary messengers, regulatory RNAs, transcription factors) of Candida involved in biofilm formation that could enable small-molecule drug discovery against these molecular determinants, and lead to disrupt the well-structured Candida biofilms effectively.
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Affiliation(s)
- Dushyant Kumar
- Department of Biotechnology, National Institute of Technology, Raipur, Chhattisgarh, 492010, India
| | - Awanish Kumar
- Department of Biotechnology, National Institute of Technology, Raipur, Chhattisgarh, 492010, India.
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2
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Rai LS, Chauvel M, Sanchez H, van Wijlick L, Maufrais C, Cokelaer T, Sertour N, Legrand M, Sanyal K, Andes DR, Bachellier-Bassi S, d’Enfert C. Metabolic reprogramming during Candida albicans planktonic-biofilm transition is modulated by the transcription factors Zcf15 and Zcf26. PLoS Biol 2024; 22:e3002693. [PMID: 38905306 PMCID: PMC11221756 DOI: 10.1371/journal.pbio.3002693] [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: 08/04/2023] [Revised: 07/03/2024] [Accepted: 05/29/2024] [Indexed: 06/23/2024] Open
Abstract
Candida albicans is a commensal of the human microbiota that can form biofilms on implanted medical devices. These biofilms are tolerant to antifungals and to the host immune system. To identify novel genes modulating C. albicans biofilm formation, we performed a large-scale screen with 2,454 C. albicans doxycycline-dependent overexpression strains and identified 16 genes whose overexpression significantly hampered biofilm formation. Among those, overexpression of the ZCF15 and ZCF26 paralogs that encode transcription factors and have orthologs only in biofilm-forming species of the Candida clade, caused impaired biofilm formation both in vitro and in vivo. Interestingly, overexpression of ZCF15 impeded biofilm formation without any defect in hyphal growth. Transcript profiling, transcription factor binding, and phenotypic microarray analyses conducted upon overexpression of ZCF15 and ZCF26 demonstrated their role in reprogramming cellular metabolism by regulating central metabolism including glyoxylate and tricarboxylic acid cycle genes. Taken together, this study has identified a new set of biofilm regulators, including ZCF15 and ZCF26, that appear to control biofilm development through their specific role in metabolic remodeling.
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Affiliation(s)
- Laxmi Shanker Rai
- Institut Pasteur, Université Paris Cité, INRAE USC2019, Unité Biologie et Pathogénicité Fongiques, Paris, France
- Department of Life Sciences, GITAM University, Bengaluru, Karnataka 561203, India
| | - Murielle Chauvel
- Institut Pasteur, Université Paris Cité, INRAE USC2019, Unité Biologie et Pathogénicité Fongiques, Paris, France
| | - Hiram Sanchez
- Department of Medicine, University of Wisconsin, Madison, Wisconsin, United States of America
| | - Lasse van Wijlick
- Institut Pasteur, Université Paris Cité, INRAE USC2019, Unité Biologie et Pathogénicité Fongiques, Paris, France
| | - Corinne Maufrais
- Institut Pasteur, Université Paris Cité, INRAE USC2019, Unité Biologie et Pathogénicité Fongiques, Paris, France
| | - Thomas Cokelaer
- Institut Pasteur, Université Paris Cité, Hub de Bioinformatique et Biostatistique, Paris, France
| | - Natacha Sertour
- Institut Pasteur, Université Paris Cité, INRAE USC2019, Unité Biologie et Pathogénicité Fongiques, Paris, France
| | - Mélanie Legrand
- Institut Pasteur, Université Paris Cité, INRAE USC2019, Unité Biologie et Pathogénicité Fongiques, Paris, France
| | - Kaustuv Sanyal
- Molecular Mycology Laboratory, Molecular Biology and Genetics Unit, Jawaharlal Nehru Centre for Advanced Scientific Research, Jakkur, Bangalore, India
- Department of Biological Sciences, Bose Institute, Unified Academic Campus, EN-80, Sector-V, Salt Lake City, Kolkata, India
| | - David R. Andes
- Department of Medicine, University of Wisconsin, Madison, Wisconsin, United States of America
| | - Sophie Bachellier-Bassi
- Institut Pasteur, Université Paris Cité, INRAE USC2019, Unité Biologie et Pathogénicité Fongiques, Paris, France
| | - Christophe d’Enfert
- Institut Pasteur, Université Paris Cité, INRAE USC2019, Unité Biologie et Pathogénicité Fongiques, Paris, France
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3
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Kalia VC, Patel SKS, Lee JK. Bacterial biofilm inhibitors: An overview. ECOTOXICOLOGY AND ENVIRONMENTAL SAFETY 2023; 264:115389. [PMID: 37634478 DOI: 10.1016/j.ecoenv.2023.115389] [Citation(s) in RCA: 8] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/18/2023] [Revised: 08/05/2023] [Accepted: 08/17/2023] [Indexed: 08/29/2023]
Abstract
Bacteria that cause infectious diseases adopt biofilms as one of their most prevalent lifestyles. Biofilms enable bacteria to tolerate environmental stress and evade antibacterial agents. This bacterial defense mechanism has rendered the use of antibiotics ineffective for the treatment of infectious diseases. However, many highly drug-resistant microbes have rapidly emerged owing to such treatments. Different signaling mechanisms regulate bacterial biofilm formation, including cyclic dinucleotide (c-di-GMP), small non-coding RNAs, and quorum sensing (QS). A cell density-dependent phenomenon, QS is associated with c-di-GMP (a global messenger), which regulates gene expression related to adhesion, extracellular matrix production, the transition from the planktonic to biofilm stage, stability, pathogenicity, virulence, and acquisition of nutrients. The article aims to provide information on inhibiting biofilm formation and disintegrating mature/preformed biofilms. This treatment enables antimicrobials to target the free-living/exposed bacterial cells at lower concentrations than those needed to treat bacteria within the biofilm. Therefore, a complementary action of antibiofilm and antimicrobial agents can be a robust strategic approach to dealing with infectious diseases. Taken together, these molecules have broad implications for human health.
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Affiliation(s)
- Vipin Chandra Kalia
- Department of Chemical Engineering, Konkuk University, 120 Neungdong-ro, Gwangjin-gu, Seoul 05029, Republic of Korea
| | - Sanjay K S Patel
- Department of Chemical Engineering, Konkuk University, 120 Neungdong-ro, Gwangjin-gu, Seoul 05029, Republic of Korea
| | - Jung-Kul Lee
- Department of Chemical Engineering, Konkuk University, 120 Neungdong-ro, Gwangjin-gu, Seoul 05029, Republic of Korea.
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Kumar D, Kumar A. Cellular Attributes of Candida albicans Biofilm-Associated in Resistance Against Multidrug and Host Immune System. Microb Drug Resist 2023; 29:423-437. [PMID: 37428599 DOI: 10.1089/mdr.2022.0347] [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] [Indexed: 07/12/2023] Open
Abstract
One of the ubiquitous hospital-acquired infections is associated with Candida albicans fungus. Usually, this commensal fungus causes no harm to its human host, as it lives mutually with mucosal/epithelial tissue surface cells. Nevertheless, due to the activity of various immune weakening factors, this commensal starts reinforcing its virulence attributes with filamentation/hyphal growth and building an absolute microcolony composed of yeast, hyphal, and pseudohyphal cells, which is suspended in an extracellular gel-like polymeric substance (EPS) called biofilms. This polymeric substance is the mixture of the secreted compounds from C. albicans as well as several host cell proteins. Indeed, the presence of these host factors makes their identification and differentiation process difficult by host immune components. The gel-like texture of the EPS makes it sticky, which adsorbs most of the extracolonial compounds traversing through it that aid in penetration hindrance. All these factors further contribute to the multidrug resistance phenotype of C. albicans biofilm that is spotlighted in this article. The mechanisms it employs to escape the host immune system are also addressed effectively. The article focuses on cellular and molecular determinants involved in the resistance of C. albicans biofilm against multidrug and the host immune system.
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Affiliation(s)
- Dushyant Kumar
- Department of Biotechnology, National Institute of Technology, Raipur, India
| | - Awanish Kumar
- Department of Biotechnology, National Institute of Technology, Raipur, India
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5
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A Proteomic Landscape of Candida albicans in the Stepwise Evolution to Fluconazole Resistance. Antimicrob Agents Chemother 2022; 66:e0210521. [PMID: 35343782 DOI: 10.1128/aac.02105-21] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
Abstract
As an opportunistic fungal pathogen, Candida albicans is a major cause of superficial and systemic infections in immunocompromised patients. The increasing rate of azole resistance in C. albicans has brought further challenges to clinical therapy. In this study, we collected five isogenic C. albicans strains recovered over discrete intervals from an HIV-infected patient who suffered 2-year recurrent oropharyngeal candidiasis. Azole resistance was known from the clinical history to have developed gradually in this patient, and this was confirmed by MIC assays of each strain. Proteomic techniques can be used to investigate more comprehensively how resistance develops in pathogenic fungi over time. Our study is the first to use tandem mass tag (TMT) labeling combined with liquid chromatography-tandem mass spectrometry (LC-MS/MS) technology to investigate the acquired resistance mechanisms of serial C. albicans isolates at the proteomic level. A total of 4,029 proteins have been identified, of which 3,766 have been quantified. Compared with Ca1, bioinformatics analysis showed that differentially expressed proteins were mainly associated with aspects such as the downregulation of glycolysis/gluconeogenesis, pyruvate metabolism, fatty acid degradation, and oxidative stress response proteins in all four subsequent strains but, remarkably, the activation of amino acid metabolism in Ca8 and Ca14 and increased protection against osmotic stress or excessive copper toxicity, upregulation of respiratory chain activity, and suppression of iron transport in Ca17. By tracing proteomic alterations in this set of isogenic resistance isolates, we acquire mechanistic insight into the steps involved in the acquisition of azole resistance in C. albicans.
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Human Cryptic Host Defence Peptide GVF27 Exhibits Anti-Infective Properties against Biofilm Forming Members of the Burkholderia cepacia Complex. Pharmaceuticals (Basel) 2022; 15:ph15020260. [PMID: 35215373 PMCID: PMC8878536 DOI: 10.3390/ph15020260] [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: 11/19/2021] [Revised: 02/01/2022] [Accepted: 02/16/2022] [Indexed: 11/16/2022] Open
Abstract
Therapeutic solutions to counter Burkholderia cepacia complex (Bcc) bacteria are challenging due to their intrinsically high level of antibiotic resistance. Bcc organisms display a variety of potential virulence factors, have a distinct lipopolysaccharide naturally implicated in antimicrobial resistance. and are able to form biofilms, which may further protect them from both host defence peptides (HDPs) and antibiotics. Here, we report the promising anti-biofilm and immunomodulatory activities of human HDP GVF27 on two of the most clinically relevant Bcc members, Burkholderia multivorans and Burkholderia cenocepacia. The effects of synthetic and labelled GVF27 were tested on B. cenocepacia and B. multivorans biofilms, at three different stages of formation, by confocal laser scanning microscopy (CLSM). Assays on bacterial cultures and on human monocytes challenged with B. cenocepacia LPS were also performed. GVF27 exerts, at different stages of formation, anti-biofilm effects towards both Bcc strains, a significant propensity to function in combination with ciprofloxacin, a relevant affinity for LPSs isolated from B. cenocepacia as well as a good propensity to mitigate the release of pro-inflammatory cytokines in human cells pre-treated with the same endotoxin. Overall, all these findings contribute to the elucidation of the main features that a good therapeutic agent directed against these extremely leathery biofilm-forming bacteria should possess.
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Das S, Goswami AM, Saha T. An insight into the role of protein kinases as virulent factors, regulating pathogenic attributes in Candida albicans. Microb Pathog 2022; 164:105418. [DOI: 10.1016/j.micpath.2022.105418] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2021] [Revised: 01/21/2022] [Accepted: 01/21/2022] [Indexed: 11/26/2022]
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8
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CO 2 enhances the formation, nutrient scavenging and drug resistance properties of C. albicans biofilms. NPJ Biofilms Microbiomes 2021; 7:67. [PMID: 34385462 PMCID: PMC8361082 DOI: 10.1038/s41522-021-00238-z] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2020] [Accepted: 07/16/2021] [Indexed: 02/07/2023] Open
Abstract
C. albicans is the predominant human fungal pathogen and frequently colonises medical devices, such as voice prostheses, as a biofilm. It is a dimorphic yeast that can switch between yeast and hyphal forms in response to environmental cues, a property that is essential during biofilm establishment and maturation. One such cue is the elevation of CO2 levels, as observed in exhaled breath for example. However, despite the clear medical relevance, the effect of CO2 on C. albicans biofilm growth has not been investigated to date. Here we show that physiologically relevant CO2 elevation enhances each stage of the C. albicans biofilm-forming process: from attachment through maturation to dispersion. The effects of CO2 are mediated via the Ras/cAMP/PKA signalling pathway and the central biofilm regulators Efg1, Brg1, Bcr1 and Ndt80. Biofilms grown under elevated CO2 conditions also exhibit increased azole resistance, increased Sef1-dependent iron scavenging and enhanced glucose uptake to support their rapid growth. These findings suggest that C. albicans has evolved to utilise the CO2 signal to promote biofilm formation within the host. We investigate the possibility of targeting CO2-activated processes and propose 2-deoxyglucose as a drug that may be repurposed to prevent C. albicans biofilm formation on medical airway management implants. We thus characterise the mechanisms by which CO2 promotes C. albicans biofilm formation and suggest new approaches for future preventative strategies.
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The Roles of Chromatin Accessibility in Regulating the Candida albicans White-Opaque Phenotypic Switch. J Fungi (Basel) 2021; 7:jof7010037. [PMID: 33435404 PMCID: PMC7826875 DOI: 10.3390/jof7010037] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2020] [Revised: 01/05/2021] [Accepted: 01/07/2021] [Indexed: 12/18/2022] Open
Abstract
Candida albicans, a diploid polymorphic fungus, has evolved a unique heritable epigenetic program that enables reversible phenotypic switching between two cell types, referred to as “white” and “opaque”. These cell types are established and maintained by distinct transcriptional programs that lead to differences in metabolic preferences, mating competencies, cellular morphologies, responses to environmental signals, interactions with the host innate immune system, and expression of approximately 20% of genes in the genome. Transcription factors (defined as sequence specific DNA-binding proteins) that regulate the establishment and heritable maintenance of the white and opaque cell types have been a primary focus of investigation in the field; however, other factors that impact chromatin accessibility, such as histone modifying enzymes, chromatin remodelers, and histone chaperone complexes, also modulate the dynamics of the white-opaque switch and have been much less studied to date. Overall, the white-opaque switch represents an attractive and relatively “simple” model system for understanding the logic and regulatory mechanisms by which heritable cell fate decisions are determined in higher eukaryotes. Here we review recent discoveries on the roles of chromatin accessibility in regulating the C. albicans white-opaque phenotypic switch.
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10
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Staniszewska M. Virulence Factors in Candida species. Curr Protein Pept Sci 2021; 21:313-323. [PMID: 31544690 DOI: 10.2174/1389203720666190722152415] [Citation(s) in RCA: 50] [Impact Index Per Article: 16.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2019] [Revised: 06/06/2019] [Accepted: 07/14/2019] [Indexed: 02/08/2023]
Abstract
Fungal diseases are severe and have very high morbidity as well as up to 60% mortality for patients diagnosed with invasive fungal infection. In this review, in vitro and in vivo studies provided us with the insight into the role of Candida virulence factors that mediate their success as pathogens, such as: membrane and cell wall (CW) barriers, dimorphism, biofilm formation, signal transduction pathway, proteins related to stress tolerance, hydrolytic enzymes (e.g. proteases, lipases, haemolysins), and toxin production. The review characterized the virulence of clinically important C. albicans, C. parapsilosis, C. tropicalis, C. glabrata and C. krusei. Due to the white-opaque transition in the mating-type locus MTL-homozygous cells, C. albicans demonstrates an advantage over other less related species of Candida as a human commensal and pathogen. It was reviewed that Candida ergosterol biosynthesis genes play a role in cellular stress and are essential for Candida pathogenesis both in invasive and superficial infections. Hydrolases associated with CW are involved in the host-pathogen interactions. Adhesins are crucial in colonization and biofilm formation, an important virulence factor for candidiasis. Calcineurin is involved in membrane and CW stress as well as virulence. The hyphae-specific toxin, named candidalysin, invades mucosal cells facilitating fungal invasion into deeper tissues. Expression of this protein promotes resistance to neutrophil killing in candidiasis. The virulence factors provide immunostimulatory factors, activating dendric cells and promoting T cell infiltration and activation. Targeting virulence factors, can reduce the risk of resistance development in Candida infections.
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Affiliation(s)
- Monika Staniszewska
- Faculty of Chemistry, Warsaw University of Technology, 00-664 Warsaw, Poland
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11
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Fungistatic Action of N-Acetylcysteine on Candida albicans Biofilms and Its Interaction with Antifungal Agents. Microorganisms 2020; 8:microorganisms8070980. [PMID: 32629850 PMCID: PMC7409114 DOI: 10.3390/microorganisms8070980] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2020] [Revised: 06/23/2020] [Accepted: 06/23/2020] [Indexed: 12/20/2022] Open
Abstract
Therapies targeted to fungal biofilms, mainly against the matrix, and therapies that do not induce microbial resistance are relevant. N-acetylcysteine (NAC), a mucolytic agent, has shown antimicrobial action. This study evaluated the effect of NAC against fluconazole-susceptible (CaS) and -resistant (CaR) Candida albicans. The susceptibility of planktonic cultures to NAC, the effect of NAC on biofilms and their matrix, the interaction of NAC with antifungal agents, and confocal microscopy were evaluated. Data were analyzed descriptively and by the ANOVA/Welch and Tukey/Gomes-Howell tests. The minimum inhibitory concentration (MIC) of NAC was 25 mg/mL for both strains. NAC significantly reduced the viability of both fungal strains. Concentrations higher than the MIC (100 and 50 mg/mL) reduced the viability and the biomass. NAC at 12.5 mg/mL increased the fungal viability. NAC also reduced the soluble components of the biofilm matrix, and showed synergism with caspofungin against planktonic cultures of CaS, but not against biofilms. Confocal images demonstrated that NAC reduced the biofilm thickness and the fluorescence intensity of most fluorochromes used. High concentrations of NAC had similar fungistatic effects against both strains, while a low concentration showed the opposite result. The antibiofilm action of NAC was due to its fungistatic action.
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Qian Y, Altamimi A, Yates SA, Sarkar S, Cochran M, Zhou M, Levi-Polyachenko N, Matson JB. H 2S-releasing amphiphilic dipeptide hydrogels are potent S. aureus biofilm disruptors. Biomater Sci 2020; 8:2564-2576. [PMID: 32232239 PMCID: PMC7250531 DOI: 10.1039/d0bm00241k] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
As a gasotransmitter, hydrogen sulfide (H2S) has been studied to treat wounds and inflammation, but its potential antimicrobial effects in this context have not been evaluated. An H2S-releasing dipeptide hydrogel (S-FE), and several non-H2S-releasing control dipeptides, (C-FE, C-GE, FBA-FE, and FE where S = S-aroylthiooxime, an H2S donor; C = control, an oxime incapable of H2S release; FBA = 4-formylbenzamide, also incapable of H2S release; and E, F, G = glutamic acid, phenylalanine, and glycine, respectively), were studied to correlate differences in their chemical structures and H2S-releasing abilities with their antimicrobial effects on Staphylococcus aureus bacteria. Dipeptides with Phe (S-FE, C-FE, and FE) self-assembled into nanoribbons in water and displayed β-sheet formation and enhanced fluorescence, while the other two dipeptides (FBA-FE and C-GE) did not form assemblies in water. In vitro experiments with Staphylococcus aureus, which is a commonly found bacterium associated with wounds, showed significant antimicrobial effects from some of the dipeptides. Dipeptide S-FE inhibited bacterial growth more effectively than any of the controls, thereby limiting biofilm formation or disrupting established biofilms. These antimicrobial H2S-releasing dipeptide hydrogels provide a promising new approach to treat wound infections.
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Affiliation(s)
- Yun Qian
- Department of Chemistry, Macromolecules Innovation Institute, and Virginia Tech Center for Drug Discovery, Virginia Tech, Blacksburg, VA 24061
| | - Afnan Altamimi
- Department of Plastic and Reconstructive Surgery, Wake Forest School of Medicine, Winston Salem, NC, USA
- King Saud University, College of Medicine, Department of Surgery, Riyadh, Saudi Arabia
| | - Shaina Alston Yates
- Department of Plastic and Reconstructive Surgery, Wake Forest School of Medicine, Winston Salem, NC, USA
| | - Santu Sarkar
- Department of Plastic and Reconstructive Surgery, Wake Forest School of Medicine, Winston Salem, NC, USA
| | - Matthew Cochran
- Department of Plastic and Reconstructive Surgery, Wake Forest School of Medicine, Winston Salem, NC, USA
| | - Mingjun Zhou
- Department of Chemistry, Macromolecules Innovation Institute, and Virginia Tech Center for Drug Discovery, Virginia Tech, Blacksburg, VA 24061
| | - Nicole Levi-Polyachenko
- Department of Plastic and Reconstructive Surgery, Wake Forest School of Medicine, Winston Salem, NC, USA
| | - John B. Matson
- Department of Chemistry, Macromolecules Innovation Institute, and Virginia Tech Center for Drug Discovery, Virginia Tech, Blacksburg, VA 24061
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Effect of progesterone on Candida albicans biofilm formation under acidic conditions: A transcriptomic analysis. Int J Med Microbiol 2020; 310:151414. [PMID: 32173268 DOI: 10.1016/j.ijmm.2020.151414] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2019] [Revised: 01/08/2020] [Accepted: 02/25/2020] [Indexed: 11/22/2022] Open
Abstract
Vulvovaginal candidiasis (VVC) caused by Candida albicans is a common disease worldwide. A very important C. albicans virulence factor is its ability to form biofilms on epithelium and/or on intrauterine devices promoting VVC. It has been shown that VVC has a hormonal dependency and that progesterone affects virulence traits of C. albicans cells. To understand how the acidic environment (pH 4) and progesterone (either alone and in combination) modulate C. albicans response during formation of biofilm, a transcriptomic analysis was performed together with characterization of the biofilm properties. Compared to planktonic cells, acidic biofilm-cells exhibited major changes in their transcriptome, including modifications in the expression of 286 genes that were not previously associated with biofilm formation in C. albicans. The vast majority of the genes up-regulated in the acidic biofilm cells (including those uniquely identified in our study) are known targets of Sfl1, and consistently, Sfl1 deletion is herein shown to impair the formation of acidic biofilms (pH 4). Under the acidic conditions used, the presence of progesterone reduced C. albicans biofilm biomass and structural cohesion. Transcriptomic analysis of biofilms developed in the presence of progesterone led to the identification of 65 down-regulated genes including, among others, the regulator Tec1 and several of its target genes, suggesting that the function of this transcription factor is inhibited by the presence of the hormone. Additionally, progesterone reduced the susceptibility of biofilm cells to fluconazole, consistent with an up-regulation of efflux pumps. Overall, the results of this study show that progesterone modulates C. albicans biofilm formation and genomic expression under acidic conditions, which may have implications for C. albicans pathogenicity in the vaginal environment.
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14
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Heme-iron acquisition in fungi. Curr Opin Microbiol 2019; 52:77-83. [DOI: 10.1016/j.mib.2019.05.006] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2019] [Revised: 05/30/2019] [Accepted: 05/31/2019] [Indexed: 01/09/2023]
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15
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Prasath KG, Sethupathy S, Pandian SK. Proteomic analysis uncovers the modulation of ergosterol, sphingolipid and oxidative stress pathway by myristic acid impeding biofilm and virulence in Candida albicans. J Proteomics 2019; 208:103503. [DOI: 10.1016/j.jprot.2019.103503] [Citation(s) in RCA: 39] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2019] [Revised: 08/10/2019] [Accepted: 08/22/2019] [Indexed: 01/16/2023]
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16
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Lobo CIV, Rinaldi TB, Christiano CMS, De Sales Leite L, Barbugli PA, Klein MI. Dual-species biofilms of Streptococcus mutans and Candida albicans exhibit more biomass and are mutually beneficial compared with single-species biofilms. J Oral Microbiol 2019; 11:1581520. [PMID: 31681463 PMCID: PMC6807867 DOI: 10.1080/20002297.2019.1581520] [Citation(s) in RCA: 40] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2018] [Revised: 01/26/2019] [Accepted: 02/06/2019] [Indexed: 12/02/2022] Open
Abstract
Background: Streptococcus mutans (Sm) and Candida albicans (Ca) are found in biofilms of early childhood caries. Objective: To characterize in vitro dual- and single-species biofilms of Sm and Ca formed on saliva-coated hydroxyapatite discs in the presence of sucrose. Design: Evaluation of biofilms included biochemical [biomass, proteins, matrix’s water-soluble (WSP) and alkali-soluble (ASP) polysaccharides, microbiological, 3D structure, gene expression, and stress tolerance analyses. Results: Biomass and proteins were higher for dual-species and lower for Ca (p = 0.001). Comparison of Sm single- and dual-species biofilms revealed no significant difference in Sm numbers or quantity of WSP (p > 0.05). Dual-species biofilms contained a higher population of Ca (p < 0.001). The quantity of ASP was higher in dual-species biofilms (vs Ca single-species biofilms; p = 0.002). The 3D structure showed larger microcolonies and distinct distribution of Sm-derived exopolysaccharides in dual-species biofilms. Compared with dual-species biofilms, expression of gtfB (ASP) and nox1 (oxidative stress) was higher for single-species of Sm whilst expression of BGL2 (matrix), PHR1 (matrix, acid tolerance) and SOD1 (oxidative stress) was higher in single-species of Ca. There was no difference for acid tolerance genes (Sm atpD and Ca PHR2), which was confirmed by acid tolerance challenge. Dual-species biofilms were more tolerant to oxidative and antimicrobial stresses (p < 0.05). Conclusions: Dual-species biofilms present greater 3D complexity, thereby, making them more resistant to stress conditions.
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Affiliation(s)
- Carmélia Isabel Vitorino Lobo
- Department of Dental Materials and Prosthodontics, São Paulo State University (Unesp), School of Dentistry, Araraquara, Brazil
| | - Talita Baptista Rinaldi
- Department of Dental Materials and Prosthodontics, São Paulo State University (Unesp), School of Dentistry, Araraquara, Brazil
| | | | - Luana De Sales Leite
- Department of Dental Materials and Prosthodontics, São Paulo State University (Unesp), School of Dentistry, Araraquara, Brazil
| | - Paula Aboud Barbugli
- Department of Dental Materials and Prosthodontics, São Paulo State University (Unesp), School of Dentistry, Araraquara, Brazil
| | - Marlise Inêz Klein
- Department of Dental Materials and Prosthodontics, São Paulo State University (Unesp), School of Dentistry, Araraquara, Brazil
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Portrait of Matrix Gene Expression in Candida glabrata Biofilms with Stress Induced by Different Drugs. Genes (Basel) 2018; 9:genes9040205. [PMID: 29642649 PMCID: PMC5924547 DOI: 10.3390/genes9040205] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2018] [Revised: 03/29/2018] [Accepted: 04/05/2018] [Indexed: 01/22/2023] Open
Abstract
(1) Background: Candida glabrata is one of the most significant Candida species associated with severe cases of candidiasis. Biofilm formation is an important feature, closely associated with antifungal resistance, involving alterations of gene expression or mutations, which can result in the failure of antifungal treatments. Hence, the main goal of this work was to evaluate the role of a set of genes, associated with matrix production, in the resistance of C. glabrata biofilms to antifungal drugs. (2) Methods: the determination of the expression of BGL2, XOG1, FKS1, FKS2, GAS2, KNH1, UGP1, and MNN2 genes in 48-h biofilm’s cells of three C. glabrata strains was performed through quantitative real-time PCR (RT-qPCR), after contact with Fluconazole (Flu), Amphotericin B (AmB), Caspofungin (Csf), or Micafungin (Mcf). (3) Results: Mcf induced a general overexpression of the selected genes. It was verified that the genes related to the production of β-1,3-glucans (BGL2, XOG1, GAS2) had the highest expressions. (4) Conclusion: though β-1,6-glucans and mannans are an essential part of the cell and biofilm matrix, C. glabrata biofilm cells seem to contribute more to the replacement of β-1,3-glucans. Thus, these biopolymers seem to have a greater impact on the biofilm matrix composition and, consequently, a role in the biofilm resistance to antifungal drugs.
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Manfiolli AO, Dos Reis TF, de Assis LJ, de Castro PA, Silva LP, Hori JI, Walker LA, Munro CA, Rajendran R, Ramage G, Goldman GH. Mitogen activated protein kinases (MAPK) and protein phosphatases are involved in Aspergillus fumigatus adhesion and biofilm formation. Cell Surf 2018; 1:43-56. [PMID: 32743127 PMCID: PMC7389341 DOI: 10.1016/j.tcsw.2018.03.002] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2018] [Revised: 03/08/2018] [Accepted: 03/14/2018] [Indexed: 12/28/2022] Open
Abstract
The main characteristic of biofilm formation is extracellular matrix (ECM) production. The cells within the biofilm are surrounded by ECM which provides structural integrity and protection. During an infection, this protection is mainly against cells of the immune system and antifungal drugs. A. fumigatus forms biofilms during static growth on a solid substratum and in chronic aspergillosis infections. It is important to understand how, and which, A. fumigatus signal transduction pathways are important for the adhesion and biofilm formation in a host during infection. Here we investigated the role of MAP kinases and protein phosphatases in biofilm formation. The loss of the MAP kinases MpkA, MpkC and SakA had an impact on the cell surface and the ECM during biofilm formation and reduced the adherence of A. fumigatus to polystyrene and fibronectin-coated plates. The phosphatase null mutants ΔsitA and ΔptcB, involved in regulation of MpkA and SakA phosphorylation, influenced cell wall carbohydrate exposure. Moreover, we characterized the A. fumigatus protein phosphatase PphA. The ΔpphA strain was more sensitive to cell wall-damaging agents, had increased β-(1,3)-glucan and reduced chitin, decreased conidia phagocytosis by Dictyostelium discoideum and reduced adhesion and biofilm formation. Finally, ΔpphA strain was avirulent in a murine model of invasive pulmonary aspergillosis and increased the released of tumor necrosis factor alpha (TNF-α) from bone marrow derived macrophages (BMDMs). These results show that MAP kinases and phosphatases play an important role in signaling pathways that regulate the composition of the cell wall, extracellular matrix production as well as adhesion and biofilm formation in A. fumigatus.
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Affiliation(s)
- Adriana Oliveira Manfiolli
- Faculdade de Ciências Farmacêuticas de Ribeirão Preto, Universidade de São Paulo, Ribeirão Preto, Brazil
| | - Thaila Fernanda Dos Reis
- Faculdade de Ciências Farmacêuticas de Ribeirão Preto, Universidade de São Paulo, Ribeirão Preto, Brazil
| | - Leandro José de Assis
- Faculdade de Ciências Farmacêuticas de Ribeirão Preto, Universidade de São Paulo, Ribeirão Preto, Brazil
| | - Patrícia Alves de Castro
- Faculdade de Ciências Farmacêuticas de Ribeirão Preto, Universidade de São Paulo, Ribeirão Preto, Brazil
| | - Lilian Pereira Silva
- Faculdade de Ciências Farmacêuticas de Ribeirão Preto, Universidade de São Paulo, Ribeirão Preto, Brazil
| | - Juliana I Hori
- Faculdade de Ciências Farmacêuticas de Ribeirão Preto, Universidade de São Paulo, Ribeirão Preto, Brazil
| | - Louise A Walker
- School of Medical Sciences, University of Aberdeen, Aberdeen, UK
| | - Carol A Munro
- School of Medical Sciences, University of Aberdeen, Aberdeen, UK
| | - Ranjith Rajendran
- Infection and Immunity Research Group, Glasgow Dental School, School of Medicine, College of Medical, Veterinary and Life Sciences, The University of Glasgow, 378 Sauchiehall Street, Glasgow G2 3JZ, UK
| | - Gordon Ramage
- Infection and Immunity Research Group, Glasgow Dental School, School of Medicine, College of Medical, Veterinary and Life Sciences, The University of Glasgow, 378 Sauchiehall Street, Glasgow G2 3JZ, UK
| | - Gustavo H Goldman
- Faculdade de Ciências Farmacêuticas de Ribeirão Preto, Universidade de São Paulo, Ribeirão Preto, Brazil
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19
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Protocol for Identifying Natural Agents That Selectively Affect Adhesion, Thickness, Architecture, Cellular Phenotypes, Extracellular Matrix, and Human White Blood Cell Impenetrability of Candida albicans Biofilms. Antimicrob Agents Chemother 2017; 61:AAC.01319-17. [PMID: 28893778 DOI: 10.1128/aac.01319-17] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2017] [Accepted: 09/04/2017] [Indexed: 11/20/2022] Open
Abstract
In the screening of natural plant extracts for antifungal activity, assessment of their effects on the growth of cells in suspension or in the wells of microtiter plates is expedient. However, microorganisms, including Candida albicans, grow in nature as biofilms, which are organized cellular communities with a complex architecture capable of conditioning their microenvironment, communicating, and excluding low- and high-molecular-weight molecules and white blood cells. Here, a confocal laser scanning microscopy (CLSM) protocol for testing the effects of large numbers of agents on biofilm development is described. The protocol assessed nine parameters from a single z-stack series of CLSM scans for each individual biofilm analyzed. The parameters included adhesion, thickness, formation of a basal yeast cell polylayer, hypha formation, the vertical orientation of hyphae, the hyphal bend point, pseudohypha formation, calcofluor white staining of the extracellular matrix (ECM), and human white blood cell impenetrability. The protocol was applied first to five plant extracts and derivative compounds and then to a collection of 88 previously untested plant extracts. They were found to cause a variety of phenotypic profiles, as was the case for 64 of the 88 extracts (73%). Half of the 46 extracts that did not affect biofilm thickness affected other biofilm parameters. Correlations between specific effects were revealed. The protocol will be useful not only in the screening of chemical libraries but also in the analysis of compounds with known effects and mutations.
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20
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Abstract
We focus this article on turning a biofilm inside out. The "inside" of the biofilm comprises the individual biofilm-related phenotypes, their environmental drivers and genetic determinants, and the coordination of gene functions through transcriptional regulators. Investigators have viewed the inside of the biofilm through diverse approaches, and this article will attempt to capture the essence of many. The ultimate goal is to connect the inside to the "outside," which we view as biofilm structure, development, pharmacological attributes, and medical impact.
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21
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Abstract
We focus this article on turning a biofilm inside out. The "inside" of the biofilm comprises the individual biofilm-related phenotypes, their environmental drivers and genetic determinants, and the coordination of gene functions through transcriptional regulators. Investigators have viewed the inside of the biofilm through diverse approaches, and this article will attempt to capture the essence of many. The ultimate goal is to connect the inside to the "outside," which we view as biofilm structure, development, pharmacological attributes, and medical impact.
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Affiliation(s)
- Katherine Lagree
- Department of Biological Sciences, Carnegie Mellon University, Pittsburgh, PA 15213
| | - Aaron P Mitchell
- Department of Biological Sciences, Carnegie Mellon University, Pittsburgh, PA 15213
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22
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Abstract
A majority of infections caused by Candida albicans—the most frequent fungal pathogen—are associated with biofilm formation. A salient feature of C. albicans biofilms is the presence of the biofilm matrix. This matrix is composed of exopolymeric materials secreted by sessile cells within the biofilm, in which all classes of macromolecules are represented, and provides protection against environmental challenges. In this review, we summarize the knowledge accumulated during the last two decades on the composition, structure, and function of the C. albicans biofilm matrix. Knowledge of the matrix components, its structure, and function will help pave the way to novel strategies to combat C. albicans biofilm infections.
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23
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Abstract
Candida albicans, the most pervasive fungal pathogen that colonizes humans, forms biofilms that are architecturally complex. They consist of a basal yeast cell polylayer and an upper region of hyphae encapsulated in extracellular matrix. However, biofilms formed in vitro vary as a result of the different conditions employed in models, the methods used to assess biofilm formation, strain differences, and, in a most dramatic fashion, the configuration of the mating type locus (MTL). Therefore, integrating data from different studies can lead to problems of interpretation if such variability is not taken into account. Here we review the conditions and factors that cause biofilm variation, with the goal of engendering awareness that more attention must be paid to the strains employed, the methods used to assess biofilm development, every aspect of the model employed, and the configuration of the MTL locus. We end by posing a set of questions that may be asked in comparing the results of different studies and developing protocols for new ones. This review should engender the notion that not all biofilms are created equal.
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Affiliation(s)
- David R Soll
- Developmental Studies Hybridoma Bank, Department of Biology, The University of Iowa, Iowa City, Iowa, USA
| | - Karla J Daniels
- Developmental Studies Hybridoma Bank, Department of Biology, The University of Iowa, Iowa City, Iowa, USA
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24
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Saputo S, Norman KL, Murante T, Horton BN, Diaz JDLC, DiDone L, Colquhoun J, Schroeder JW, Simmons LA, Kumar A, Krysan DJ. Complex Haploinsufficiency-Based Genetic Analysis of the NDR/Lats Kinase Cbk1 Provides Insight into Its Multiple Functions in Candida albicans. Genetics 2016; 203:1217-33. [PMID: 27206715 PMCID: PMC4937472 DOI: 10.1534/genetics.116.188029] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2016] [Accepted: 05/11/2016] [Indexed: 01/11/2023] Open
Abstract
Although the analysis of genetic interactions and networks is a powerful approach to understanding biology, it has not been applied widely to the pathogenic yeast Candida albicans Here, we describe the use of both screening and directed genetic interaction studies based on complex haploinsufficiency to probe the function of the R: egulation of A: ce2 and M: orphogenesis (RAM) pathway in C. albicans A library of 5200 Tn7-mutagenized derivatives of a parental strain heterozygous at CBK1, the key kinase in the RAM pathway, was screened for alterations in serum-induced filamentation. Following confirmation of phenotypes and identification of insertion sites by sequencing, a set of 36 unique double heterozygous strains showing complex haploinsufficiency was obtained. In addition to a large set of genes regulated by the RAM transcription factor Ace2, genes related to cell wall biosynthesis, cell cycle, polarity, oxidative stress, and nitrogen utilization were identified. Follow-up analysis led to the first demonstration that the RAM pathway is required for oxidative stress tolerance in a manner related to the two-component-regulated kinase Chk1 and revealed a potential direct connection between the RAM pathway and the essential Mps1 spindle pole-related kinase. In addition, genetic interactions with CDC42-related genes MSB1, a putative scaffold protein, and RGD3, a putative Rho GTPase-activating protein (GAP) were identified. We also provide evidence that Rgd3 is a GAP for Cdc42 and show that its localization and phosphorylation are dependent on Cbk1.
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Affiliation(s)
- Sarah Saputo
- Department of Microbiology/Immunology University of Rochester School of Medicine and Dentistry, Rochester, New York 14642
| | - Kaitlyn L Norman
- Department of Molecular, Cellular, and Developmental Biology, University of Michigan, Ann Arbor, Michigan 48109
| | - Thomas Murante
- Department of Pediatrics, University of Rochester School of Medicine and Dentistry, Rochester, New York 14642
| | - Brooke N Horton
- Department of Molecular, Cellular, and Developmental Biology, University of Michigan, Ann Arbor, Michigan 48109
| | - Jacinto De La Cruz Diaz
- Department of Microbiology/Immunology University of Rochester School of Medicine and Dentistry, Rochester, New York 14642
| | - Louis DiDone
- Department of Pediatrics, University of Rochester School of Medicine and Dentistry, Rochester, New York 14642
| | - Jennifer Colquhoun
- Department of Microbiology/Immunology University of Rochester School of Medicine and Dentistry, Rochester, New York 14642
| | - Jeremy W Schroeder
- Department of Molecular, Cellular, and Developmental Biology, University of Michigan, Ann Arbor, Michigan 48109
| | - Lyle A Simmons
- Department of Molecular, Cellular, and Developmental Biology, University of Michigan, Ann Arbor, Michigan 48109
| | - Anuj Kumar
- Department of Molecular, Cellular, and Developmental Biology, University of Michigan, Ann Arbor, Michigan 48109
| | - Damian J Krysan
- Department of Microbiology/Immunology University of Rochester School of Medicine and Dentistry, Rochester, New York 14642 Department of Pediatrics, University of Rochester School of Medicine and Dentistry, Rochester, New York 14642
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25
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Abstract
In humans, microbial cells (including bacteria, archaea, and fungi) greatly outnumber host cells. Candida albicans is the most prevalent fungal species of the human microbiota; this species asymptomatically colonizes many areas of the body, particularly the gastrointestinal and genitourinary tracts of healthy individuals. Alterations in host immunity, stress, resident microbiota, and other factors can lead to C. albicans overgrowth, causing a wide range of infections, from superficial mucosal to hematogenously disseminated candidiasis. To date, most studies of C. albicans have been carried out in suspension cultures; however, the medical impact of C. albicans (like that of many other microorganisms) depends on its ability to thrive as a biofilm, a closely packed community of cells. Biofilms are notorious for forming on implanted medical devices, including catheters, pacemakers, dentures, and prosthetic joints, which provide a surface and sanctuary for biofilm growth. C. albicans biofilms are intrinsically resistant to conventional antifungal therapeutics, the host immune system, and other environmental perturbations, making biofilm-based infections a significant clinical challenge. Here, we review our current knowledge of biofilms formed by C. albicans and closely related fungal species.
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Affiliation(s)
- Clarissa J Nobile
- Department of Molecular and Cell Biology, School of Natural Sciences, University of California, Merced, California 95343;
| | - Alexander D Johnson
- Department of Microbiology and Immunology, University of California, San Francisco, California 94143;
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26
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Binding Sites in the EFG1 Promoter for Transcription Factors in a Proposed Regulatory Network: A Functional Analysis in the White and Opaque Phases of Candida albicans. G3-GENES GENOMES GENETICS 2016; 6:1725-37. [PMID: 27172219 PMCID: PMC4889668 DOI: 10.1534/g3.116.029785] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
In Candida albicans the transcription factor Efg1, which is differentially expressed in the white phase of the white-opaque transition, is essential for expression of the white phenotype. It is one of six transcription factors included in a proposed interactive transcription network regulating white-opaque switching and maintenance of the alternative phenotypes. Ten sites were identified in the EFG1 promoter that differentially bind one or more of the network transcription factors in the white and/or opaque phase. To explore the functionality of these binding sites in the differential expression of EFG1, we generated targeted deletions of each of the 10 binding sites, combinatorial deletions, and regional deletions using a Renillareniformis luciferase reporter system. Individually targeted deletion of only four of the 10 sites had minor effects consistent with differential expression of EFG1, and only in the opaque phase. Alternative explanations are considered.
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27
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Abstract
The fungus Candida albicans is a major source of device-associated infection because of its capacity for biofilm formation. It is part of the natural mucosal flora and thus has access to available niches that can lead to infection. In this chapter we discuss the major properties of C. albicans biofilms and the insight that has been gleaned from their genetic determinants. Our specific areas of focus include biofilm structure and development, cell morphology and biofilm formation, biofilm-associated gene expression, the cell surface and adherence, the extracellular matrix, biofilm metabolism, and biofilm drug resistance.
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28
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Mitchell KF, Zarnowski R, Andes DR. The Extracellular Matrix of Fungal Biofilms. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2016; 931:21-35. [PMID: 27271680 DOI: 10.1007/5584_2016_6] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
Abstract
A key feature of biofilms is their production of an extracellular matrix. This material covers the biofilm cells, providing a protective barrier to the surrounding environment. During an infection setting, this can include such offenses as host cells and products of the immune system as well as drugs used for treatment. Studies over the past two decades have revealed the matrix from different biofilm species to be as diverse as the microbes themselves. This chapter will review the composition and roles of matrix from fungal biofilms, with primary focus on Candida species, Saccharomyces cerevisiae, Aspergillus fumigatus, and Cryptococcus neoformans. Additional coverage will be provided on the antifungal resistance proffered by the Candida albicans matrix, which has been studied in the most depth. A brief section on the matrix produced by bacterial biofilms will be provided for comparison. Current tools for studying the matrix will also be discussed, as well as suggestions for areas of future study in this field.
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Affiliation(s)
- Kaitlin F Mitchell
- Department of Medicine, University of Wisconsin-Madison, Madison, WI, USA
| | - Robert Zarnowski
- Department of Medicine, University of Wisconsin-Madison, Madison, WI, USA
| | - David R Andes
- Department of Medicine, University of Wisconsin-Madison, Madison, WI, USA.
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29
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Fungal Biofilms: Update on Resistance. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2016; 931:37-47. [DOI: 10.1007/5584_2016_7] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
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30
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Comparison of Switching and Biofilm Formation between MTL-Homozygous Strains of Candida albicans and Candida dubliniensis. EUKARYOTIC CELL 2015; 14:1186-202. [PMID: 26432632 DOI: 10.1128/ec.00146-15] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/31/2015] [Accepted: 09/23/2015] [Indexed: 11/20/2022]
Abstract
Candida albicans and Candida dubliniensis are highly related species that share the same main developmental programs. In C. albicans, it has been demonstrated that the biofilms formed by strains heterozygous and homozygous at the mating type locus (MTL) differ functionally, but studies rarely identify the MTL configuration. This becomes a particular problem in studies of C. dubliniensis, given that one-third of natural strains are MTL homozygous. For that reason, we have analyzed MTL-homozygous strains of C. dubliniensis for their capacity to switch from white to opaque, the stability of the opaque phenotype, CO2 induction of switching, pheromone induction of adhesion, the effects of minority opaque cells on biofilm thickness and dry weight, and biofilm architecture in comparison with C. albicans. Our results reveal that C. dubliniensis strains switch to opaque at lower average frequencies, exhibit a far lower level of opaque phase stability, are not stimulated to switch by high CO2, exhibit more variability in biofilm architecture, and most notably, form mature biofilms composed predominately of pseudohyphae rather than true hyphae. Therefore, while several traits of MTL-homozygous strains of C. dubliniensis appear to be degenerating or have been lost, others, most notably several related to biofilm formation, have been conserved. Within this context, the possibility is considered that C. dubliniensis is transitioning from a hypha-dominated to a pseudohypha-dominated biofilm and that aspects of C. dubliniensis colonization may provide insights into the selective pressures that are involved.
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31
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Treviño-Rangel RDJ, Rodríguez-Sánchez IP, Rosas-Taraco AG, Hernández-Bello R, González JG, González GM. Biofilm formation and genetic variability of BCR1 gene in the Candida parapsilosis complex. Rev Iberoam Micol 2015; 32:180-4. [DOI: 10.1016/j.riam.2014.11.001] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2014] [Revised: 09/13/2014] [Accepted: 11/11/2014] [Indexed: 10/24/2022] Open
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32
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Bruder-Nascimento A, Camargo CH, Mondelli AL, Sugizaki MF, Sadatsune T, Bagagli E. Candida species biofilm and Candida albicans ALS3 polymorphisms in clinical isolates. Braz J Microbiol 2015; 45:1371-7. [PMID: 25763043 PMCID: PMC4323312 DOI: 10.1590/s1517-83822014000400030] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2013] [Accepted: 04/17/2014] [Indexed: 02/08/2023] Open
Abstract
Over the last decades, there have been important changes in the epidemiology of Candida infections. In recent years, Candida species have emerged as important causes of invasive infections mainly among immunocompromised patients. This study analyzed Candida spp. isolates and compared the frequency and biofilm production of different species among the different sources of isolation: blood, urine, vulvovaginal secretions and peritoneal dialysis fluid. Biofilm production was quantified in 327 Candida isolates obtained from patients attended at a Brazilian tertiary public hospital (Botucatu, Sao Paulo). C. albicans ALS3 gene polymorphism was also evaluated by determining the number of repeated motifs in the central domain. Of the 198 total biofilm-positive isolates, 72 and 126 were considered as low and high biofilm producers, respectively. Biofilm production by C. albicans was significantly lower than that by non-albicans isolates and was most frequently observed in C. tropicalis. Biofilm production was more frequent among bloodstream isolates than other clinical sources, in urine, the isolates displayed a peculiar distribution by presenting two distinct peaks, one containing biofilm-negative isolates and the other containing isolates with intense biofilm production. The numbers of tandem-repeat copies per allele were not associated with biofilm production, suggesting the evolvement of other genetic determinants.
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Affiliation(s)
- Ariane Bruder-Nascimento
- Instituto de Biociências de Botucatu Universidade Estadual Paulista "Júlio de Mesquita Filho" BotucatuSP Brazil Instituto de Biociências de Botucatu, Universidade Estadual Paulista "Júlio de Mesquita Filho", Botucatu, SP, Brazil
| | - Carlos Henrique Camargo
- Instituto de Biociências de Botucatu Universidade Estadual Paulista "Júlio de Mesquita Filho" BotucatuSP Brazil Instituto de Biociências de Botucatu, Universidade Estadual Paulista "Júlio de Mesquita Filho", Botucatu, SP, Brazil
| | - Alessandro Lia Mondelli
- Faculdade de Medicina de Botucatu Universidade Estadual Paulista "Júlio de Mesquita Filho" BotucatuSP Brazil Faculdade de Medicina de Botucatu, Universidade Estadual Paulista "Júlio de Mesquita Filho", Botucatu, SP, Brazil
| | - Maria Fátima Sugizaki
- Instituto de Biociências de Botucatu Universidade Estadual Paulista "Júlio de Mesquita Filho" BotucatuSP Brazil Instituto de Biociências de Botucatu, Universidade Estadual Paulista "Júlio de Mesquita Filho", Botucatu, SP, Brazil
| | - Terue Sadatsune
- Instituto de Biociências de Botucatu Universidade Estadual Paulista "Júlio de Mesquita Filho" BotucatuSP Brazil Instituto de Biociências de Botucatu, Universidade Estadual Paulista "Júlio de Mesquita Filho", Botucatu, SP, Brazil
| | - Eduardo Bagagli
- Instituto de Biociências de Botucatu Universidade Estadual Paulista "Júlio de Mesquita Filho" BotucatuSP Brazil Instituto de Biociências de Botucatu, Universidade Estadual Paulista "Júlio de Mesquita Filho", Botucatu, SP, Brazil
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33
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Role of Tec1 in the development, architecture, and integrity of sexual biofilms of Candida albicans. EUKARYOTIC CELL 2015; 14:228-40. [PMID: 25556183 DOI: 10.1128/ec.00224-14] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
MTL-homozygous ( A: / A: or α/α) white cells form a complex sexual biofilm that exhibits the same architecture as that of MTL-heterozygous ( A: /α) pathogenic biofilms. However, the former is regulated by the mitogen-activated protein (MAP) kinase pathway, while the latter is regulated by the Ras1/cyclic AMP (cAMP) pathway. We previously demonstrated that in the formation of an MTL-homozygous, mature (48 h) sexual biofilm in RPMI 1640 medium, the MAP kinase pathway targets Tec1 rather than Cph1, the latter of which is the target of the same pathway, but for the opaque cell mating response. Here we continued our analysis of the role of Tec1 by comparing the effects of deleting TEC1 on initial adhesion to silicone elastomer, high-resolution confocal microscopy assessments of the stages and cellular phenotypes during the 48 h of biofilm development, human white cell penetration, and biofilm fragility. We show that although Tec1 plays only a minor role in initial adhesion to the silicone elastomer, it does play a major role in the growth of the basal yeast cell polylayer, vertical extension of hyphae and matrix deposition in the upper portion of the biofilm, final biofilm thickness, penetrability of human white blood cells, and final biofilm integrity (i.e., resistance to fluid flow). These results provide a more detailed description of normal biofilm development and architecture and confirm the central role played by the transcription factor Tec1 in the biofilm model employed here.
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34
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Desai JV, Mitchell AP, Andes DR. Fungal biofilms, drug resistance, and recurrent infection. Cold Spring Harb Perspect Med 2014; 4:4/10/a019729. [PMID: 25274758 DOI: 10.1101/cshperspect.a019729] [Citation(s) in RCA: 163] [Impact Index Per Article: 16.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
Abstract
A biofilm is a surface-associated microbial community. Diverse fungi are capable of biofilm growth. The significance of this growth form for infection biology is that biofilm formation on implanted devices is a major cause of recurrent infection. Biofilms also have limited drug susceptibility, making device-associated infection extremely difficult to treat. Biofilm-like growth can occur during many kinds of infection, even when an implanted device is not present. Here we summarize the current understanding of fungal biofilm formation, its genetic control, and the basis for biofilm drug resistance.
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Affiliation(s)
- Jigar V Desai
- Department of Biological Sciences, Carnegie Mellon University, Pittsburgh, Pennsylvania 15213
| | - Aaron P Mitchell
- Department of Biological Sciences, Carnegie Mellon University, Pittsburgh, Pennsylvania 15213
| | - David R Andes
- Department of Medicine, University of Wisconsin, Madison, Wisconsin 53705
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35
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Lusche DF, Wessels D, Richardson NA, Russell KB, Hanson BM, Soll BA, Lin BH, Soll DR. PTEN redundancy: overexpressing lpten, a homolog of Dictyostelium discoideum ptenA, the ortholog of human PTEN, rescues all behavioral defects of the mutant ptenA-. PLoS One 2014; 9:e108495. [PMID: 25247494 PMCID: PMC4172592 DOI: 10.1371/journal.pone.0108495] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2014] [Accepted: 08/22/2014] [Indexed: 11/18/2022] Open
Abstract
Mutations in the tumor suppressor gene PTEN are associated with a significant proportion of human cancers. Because the human genome also contains several homologs of PTEN, we considered the hypothesis that if a homolog, functionally redundant with PTEN, can be overexpressed, it may rescue the defects of a PTEN mutant. We have performed an initial test of this hypothesis in the model system Dictyostelium discoideum, which contains an ortholog of human PTEN, ptenA. Deletion of ptenA results in defects in motility, chemotaxis, aggregation and multicellular morphogenesis. D. discoideum also contains lpten, a newly discovered homolog of ptenA. Overexpressing lpten completely rescues all developmental and behavioral defects of the D. discoideum mutant ptenA−. This hypothesis must now be tested in human cells.
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Affiliation(s)
- Daniel F. Lusche
- Monoclonal Antibody Research Institute and Developmental Studies Hybridoma Bank, Department of Biology, The University of Iowa, Iowa City, Iowa, United States of America
| | - Deborah Wessels
- Monoclonal Antibody Research Institute and Developmental Studies Hybridoma Bank, Department of Biology, The University of Iowa, Iowa City, Iowa, United States of America
| | - Nicole A. Richardson
- Monoclonal Antibody Research Institute and Developmental Studies Hybridoma Bank, Department of Biology, The University of Iowa, Iowa City, Iowa, United States of America
| | - Kanoe B. Russell
- Monoclonal Antibody Research Institute and Developmental Studies Hybridoma Bank, Department of Biology, The University of Iowa, Iowa City, Iowa, United States of America
| | - Brett M. Hanson
- Monoclonal Antibody Research Institute and Developmental Studies Hybridoma Bank, Department of Biology, The University of Iowa, Iowa City, Iowa, United States of America
| | - Benjamin A. Soll
- Monoclonal Antibody Research Institute and Developmental Studies Hybridoma Bank, Department of Biology, The University of Iowa, Iowa City, Iowa, United States of America
| | - Benjamin H. Lin
- Monoclonal Antibody Research Institute and Developmental Studies Hybridoma Bank, Department of Biology, The University of Iowa, Iowa City, Iowa, United States of America
| | - David R. Soll
- Monoclonal Antibody Research Institute and Developmental Studies Hybridoma Bank, Department of Biology, The University of Iowa, Iowa City, Iowa, United States of America
- * E-mail:
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Holland LM, Schröder MS, Turner SA, Taff H, Andes D, Grózer Z, Gácser A, Ames L, Haynes K, Higgins DG, Butler G. Comparative phenotypic analysis of the major fungal pathogens Candida parapsilosis and Candida albicans. PLoS Pathog 2014; 10:e1004365. [PMID: 25233198 PMCID: PMC4169492 DOI: 10.1371/journal.ppat.1004365] [Citation(s) in RCA: 92] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2014] [Accepted: 07/28/2014] [Indexed: 01/15/2023] Open
Abstract
Candida parapsilosis and Candida albicans are human fungal pathogens that belong to the CTG clade in the Saccharomycotina. In contrast to C. albicans, relatively little is known about the virulence properties of C. parapsilosis, a pathogen particularly associated with infections of premature neonates. We describe here the construction of C. parapsilosis strains carrying double allele deletions of 100 transcription factors, protein kinases and species-specific genes. Two independent deletions were constructed for each target gene. Growth in >40 conditions was tested, including carbon source, temperature, and the presence of antifungal drugs. The phenotypes were compared to C. albicans strains with deletions of orthologous transcription factors. We found that many phenotypes are shared between the two species, such as the role of Upc2 as a regulator of azole resistance, and of CAP1 in the oxidative stress response. Others are unique to one species. For example, Cph2 plays a role in the hypoxic response in C. parapsilosis but not in C. albicans. We found extensive divergence between the biofilm regulators of the two species. We identified seven transcription factors and one protein kinase that are required for biofilm development in C. parapsilosis. Only three (Efg1, Bcr1 and Ace2) have similar effects on C. albicans biofilms, whereas Cph2, Czf1, Gzf3 and Ume6 have major roles in C. parapsilosis only. Two transcription factors (Brg1 and Tec1) with well-characterized roles in biofilm formation in C. albicans do not have the same function in C. parapsilosis. We also compared the transcription profile of C. parapsilosis and C. albicans biofilms. Our analysis suggests the processes shared between the two species are predominantly metabolic, and that Cph2 and Bcr1 are major biofilm regulators in C. parapsilosis. Candida species are among the most common causes of fungal infection worldwide. Infections can be both community-based and hospital-acquired, and are particularly associated with immunocompromised individuals. Candida albicans is the most commonly isolated species and is the best studied. However, other species are becoming of increasing concern. Candida parapsilosis causes outbreaks of infection in neonatal wards, and is one of the few Candida species that is transferred from the hands of healthcare workers. C. parapsilosis, like C. albicans, grows as biofilms (cell communities) on the surfaces of indwelling medical devices like feeding tubes. We describe here the construction of a set of tools that allow us to characterize the virulence properties of C. parapsilosis, and in particular its ability to grow as biofilms. We find that some of the regulatory mechanisms are shared with C. albicans, but others are unique to each species. Our tools, based on selectively deleting regulatory genes, will provide a major resource to the fungal research community.
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Affiliation(s)
- Linda M. Holland
- School of Biomedical and Biomolecular Science, Conway Institute, University College Dublin, Belfield, Dublin, Ireland
| | - Markus S. Schröder
- School of Biomedical and Biomolecular Science, Conway Institute, University College Dublin, Belfield, Dublin, Ireland
| | - Siobhán A. Turner
- School of Biomedical and Biomolecular Science, Conway Institute, University College Dublin, Belfield, Dublin, Ireland
| | - Heather Taff
- Departments of Medicine and Microbiology and Immunology, University of Wisconsin, Madison, Madison, Wisconsin, United States of America
| | - David Andes
- Departments of Medicine and Microbiology and Immunology, University of Wisconsin, Madison, Madison, Wisconsin, United States of America
| | - Zsuzsanna Grózer
- Department of Microbiology, University of Szeged, Szeged, Hungary
| | - Attila Gácser
- Department of Microbiology, University of Szeged, Szeged, Hungary
| | - Lauren Ames
- School of Biosciences, University of Exeter, Exeter, Devon, United Kingdom
| | - Ken Haynes
- School of Biosciences, University of Exeter, Exeter, Devon, United Kingdom
| | - Desmond G. Higgins
- School of Medicine and Medical Science, Conway Institute, University College Dublin, Belfield, Dublin, Ireland
| | - Geraldine Butler
- School of Biomedical and Biomolecular Science, Conway Institute, University College Dublin, Belfield, Dublin, Ireland
- * E-mail:
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Tsai PW, Chen YT, Yang CY, Chen HF, Tan TS, Lin TW, Hsieh WP, Lan CY. The role of Mss11 in Candida albicans biofilm formation. Mol Genet Genomics 2014; 289:807-19. [PMID: 24752399 DOI: 10.1007/s00438-014-0846-0] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2013] [Accepted: 03/22/2014] [Indexed: 01/08/2023]
Abstract
Candida albicans is an opportunistic human pathogen that can form a biofilm on biotic or inert surfaces such as epithelia and clinical devices. In this study, we examine the formation of C. albicans biofilm by establishing a key gene-centered network based on protein-protein interaction (PPI) and gene expression datasets. Starting from C. albicans Cph1 and Efg1, transcription factors associated with morphogenesis of biofilm formation, a network elucidates the complex cellular process and predicts potential unknown components related to biofilm formation. Subsequently, we analyzed the functions of Mss11 among these identified proteins to test the efficiency of the proposed computational approach. MSS11-deleted mutants were compared with a wild-type strain, indicating that the mutant is defective in forming a mature biofilm and partially attenuates the virulence of C. albicans in an infected mouse model. Finally, a DNA microarray analysis was conducted to identify the potential target genes of C. albicans Mss11. The findings of this study clarify complex gene or protein interaction during the biofilm formation process of C. albicans, supporting the application of a systems biology approach to study fungal pathogenesis.
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Affiliation(s)
- Pei-Wen Tsai
- Institute of Molecular and Cellular Biology, National Tsing Hua University, No. 101, Section 2, Kuang-Fu Road, Hsinchu, 30013, Taiwan, ROC
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Candida Biofilm: Clinical Implications of Recent Advances in Research. CURRENT FUNGAL INFECTION REPORTS 2014. [DOI: 10.1007/s12281-014-0176-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
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Soll DR. The role of phenotypic switching in the basic biology and pathogenesis of Candida albicans. J Oral Microbiol 2014; 6:22993. [PMID: 24455104 PMCID: PMC3895265 DOI: 10.3402/jom.v6.22993] [Citation(s) in RCA: 60] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2013] [Revised: 11/27/2013] [Accepted: 11/28/2013] [Indexed: 11/14/2022] Open
Abstract
The "white-opaque" transition in Candida albicans was discovered in 1987. For the next fifteen years, a significant body of knowledge accumulated that included differences between the cell types in gene expression, cellular architecture and virulence in cutaneous and systemic mouse models. However, it was not until 2002 that we began to understand the role of switching in the life history of this pathogen, the role of the mating type locus and the molecular pathways that regulated it. Then in 2006, both the master switch locus WORI and the pheromone-induced white cell biofilm were discovered. Since that year, a number of new observations on the regulation and biology of switching have been made that have significantly increased the perceived complexity of this fascinating phenotypic transition.
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Affiliation(s)
- David R Soll
- Developmental Studies Hybridoma Bank, Department of Biology and College of Dentistry, University of Iowa, Iowa City, IA, USA
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Fungal morphogenetic pathways are required for the hallmark inflammatory response during Candida albicans vaginitis. Infect Immun 2013; 82:532-43. [PMID: 24478069 DOI: 10.1128/iai.01417-13] [Citation(s) in RCA: 119] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
Vulvovaginal candidiasis, caused primarily by Candida albicans, presents significant health issues for women of childbearing age. As a polymorphic fungus, the ability of C. albicans to switch between yeast and hyphal morphologies is considered its central virulence attribute. Armed with new criteria for defining vaginitis immunopathology, the purpose of this study was to determine whether the yeast-to-hypha transition is required for the hallmark inflammatory responses previously characterized during murine vaginitis. Kinetic analyses of vaginal infection with C. albicans in C57BL/6 mice demonstrated that fungal burdens remained constant throughout the observation period, while polymorphonuclear leukocyte (PMN), S100A8, and interleukin-1β levels obtained from vaginal lavage fluid increased by day 3 onward. Lactate dehydrogenase activity was also positively correlated with increased effectors of innate immunity. Additionally, immunodepletion of neutrophils in infected mice confirmed a nonprotective role for PMNs during vaginitis. Determination of the importance of fungal morphogenesis during vaginitis was addressed with a two-pronged approach. Intravaginal inoculation of mice with C. albicans strains deleted for key transcriptional regulators (bcr1Δ/Δ, efg1Δ/Δ, cph1Δ/Δ, and efg1Δ/Δ cph1Δ/Δ) controlling the yeast-to-hypha switch revealed a crucial role for morphogenetic signaling through the Efg1 and, to a lesser extent, the Bcr1 pathways in contributing to vaginitis immunopathology. Furthermore, overexpression of transcription factors NRG1 and UME6, to maintain yeast and hyphal morphologies, respectively, confirmed the importance of morphogenesis in generating innate immune responses in vivo. These results highlight the yeast-to-hypha switch and the associated morphogenetic response as important virulence components for the immunopathogenesis of Candida vaginitis, with implications for transition from benign colonization to symptomatic infection.
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Novel Regulatory Mechanisms of Pathogenicity and Virulence to Combat MDR in Candida albicans. Int J Microbiol 2013; 2013:240209. [PMID: 24163696 PMCID: PMC3791847 DOI: 10.1155/2013/240209] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2013] [Revised: 08/15/2013] [Accepted: 08/15/2013] [Indexed: 01/19/2023] Open
Abstract
Continuous deployment of antifungals in treating infections caused by dimorphic opportunistic pathogen Candida albicans has led to the emergence of drug resistance resulting in cross-resistance to many unrelated drugs, a phenomenon termed multidrug resistance (MDR). Despite the current understanding of major factors which contribute to MDR mechanisms, there are many lines of evidence suggesting that it is a complex interplay of multiple factors which may be contributed by still unknown mechanisms. Coincidentally with the increased usage of antifungal drugs, the number of reports for antifungal drug resistance has also increased which further highlights the need for understanding novel molecular mechanisms which can be explored to combat MDR, namely, ROS, iron, hypoxia, lipids, morphogenesis, and transcriptional and signaling networks. Considering the worrying evolution of MDR and significance of C. albicans being the most prevalent human fungal pathogen, this review summarizes these new regulatory mechanisms which could be exploited to prevent MDR development in C. albicans as established from recent studies.
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Impact of environmental conditions on the form and function of Candida albicans biofilms. EUKARYOTIC CELL 2013; 12:1389-402. [PMID: 23954841 DOI: 10.1128/ec.00127-13] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Candida albicans, like other pathogens, can form complex biofilms on a variety of substrates. However, as the number of studies of gene regulation, architecture, and pathogenic traits of C. albicans biofilms has increased, so have differences in results. This suggests that depending upon the conditions employed, biofilms may vary widely, thus hampering attempts at a uniform description. Gene expression studies suggest that this may be the case. To explore this hypothesis further, we compared the architectures and traits of biofilms formed in RPMI 1640 and Spider media at 37°C in air. Biofilms formed by a/α cells in the two media differed to various degrees in cellular architecture, matrix deposition, penetrability by leukocytes, fluconazole susceptibility, and the facilitation of mating. Similar comparisons of a/a cells in the two media, however, were made difficult given that in air, although a/a cells form traditional biofilms in RPMI medium, they form polylayers composed primarily of yeast cells in Spider medium. These polylayers lack an upper hyphal/matrix region, are readily penetrated by leukocytes, are highly fluconazole susceptible, and do not facilitate mating. If, however, air is replaced with 20% CO2, a/a cells make a biofilm in Spider medium similar architecturally to that of a/α cells, which facilitates mating. A second, more cursory comparison is made between the disparate cellular architectures of a/a biofilms formed in air in RPMI and Lee's media. The results demonstrate that C. albicans forms very different types of biofilms depending upon the composition of the medium, level of CO2 in the atmosphere, and configuration of the MTL locus.
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Soll DR. The evolution of alternative biofilms in an opportunistic fungal pathogen: an explanation for how new signal transduction pathways may evolve. INFECTION GENETICS AND EVOLUTION 2013; 22:235-43. [PMID: 23871837 DOI: 10.1016/j.meegid.2013.07.013] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/30/2013] [Revised: 07/11/2013] [Accepted: 07/12/2013] [Indexed: 10/26/2022]
Abstract
The evolution of two types of biofilms, one pathogenic and one sexual, is unique for Candidaalbicans, the most pervasive fungal pathogen in humans. When in the predominant a/α configuration, cells can form a traditional biofilm made up of a basal layer of yeast cells and an extensive upper layer of hyphae and dense matrix. This a/α biofilm is impermeable, impenetrable and drug-resistant. When in the a/a or α/α configuration, white cells form a biofilm of similar architecture, but which is permeable, penetrable and drug-susceptible. The latter biofilm facilitates mating between minority opaque a/a and α/α cells. The two biofilms are regulated by different signal transduction pathways that provide clues for deducing not only how the sexual a/a or α/α biofilms evolved, but how the pathogenic a/α biofilm evolved as well. In the deduced evolutionary models, regulatory molecules, including components of the signal transduction pathways and transcription factors, are recruited from conserved pathways. The evolution of the alternative biofilms of C. albicans provides a rare glimpse into how new regulatory pathways may evolve in general.
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Affiliation(s)
- David R Soll
- The Developmental Studies Hybridoma Bank, Department of Biology, University of Iowa, Iowa City, IA 52242, United States.
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Candida albicans forms a specialized "sexual" as well as "pathogenic" biofilm. EUKARYOTIC CELL 2013; 12:1120-31. [PMID: 23771904 DOI: 10.1128/ec.00112-13] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
Candida albicans forms two types of biofilm in RPMI 1640 medium, depending upon the configuration of the mating type locus. In the prevalent a/α configuration, cells form a biofilm that is impermeable, impenetrable by leukocytes, and fluconazole resistant. It is regulated by the Ras1/cyclic AMP (cAMP) pathway. In the a/a or α/α configuration, white cells form a biofilm that is architecturally similar to an a/α biofilm but, in contrast, is permeable, penetrable, and fluconazole susceptible. It is regulated by the mitogen-activated protein (MAP) kinase pathway. The MTL-homozygous biofilm has been shown to facilitate chemotropism, a step in the mating process. This has led to the hypothesis that specialized MTL-homozygous biofilms facilitate mating. If true, then MTL-homozygous biofilms should have an advantage over MTL-heterozygous biofilms in supporting mating. We have tested this prediction using a complementation strategy and show that minority opaque a/a and α/α cells seeded in MTL-homozygous biofilms mate at frequencies 1 to 2 orders of magnitude higher than in MTL-heterozygous biofilms. No difference in mating frequencies was observed between seeded patches of MTL-heterozygous and MTL-homozygous cells grown on agar at 28°C in air or 20% CO2 and at 37°C. Mating frequencies are negligible in seeded patches of both a/α and a/a cells, in contrast to seeded biofilms. Together, these results support the hypothesis that MTL-homozygous (a/a or α/α) white cells form a specialized "sexual biofilm."
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