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Feng Z, Lu H, Jiang Y. Promising immunotherapeutic targets for treating candidiasis. Front Cell Infect Microbiol 2024; 14:1339501. [PMID: 38404288 PMCID: PMC10884116 DOI: 10.3389/fcimb.2024.1339501] [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: 11/16/2023] [Accepted: 01/29/2024] [Indexed: 02/27/2024] Open
Abstract
In the last twenty years, there has been a significant increase in invasive fungal infections, which has corresponded with the expanding population of individuals with compromised immune systems. As a result, the mortality rate linked to these infections remains unacceptably high. The currently available antifungal drugs, such as azoles, polyenes, and echinocandins, face limitations in terms of their diversity, the escalating resistance of fungi and the occurrence of significant adverse effects. Consequently, there is an urgent need to develop new antifungal medications. Vaccines and antibodies present a promising avenue for addressing fungal infections due to their targeted antifungal properties and ability to modulate the immune response. This review investigates the structure and function of cell wall proteins, secreted proteins, and functional proteins within C. albicans. Furthermore, it seeks to analyze the current advancements and challenges in macromolecular drugs to identify new targets for the effective management of candidiasis.
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Affiliation(s)
| | - Hui Lu
- Department of Pharmacy, Shanghai Tenth People’s Hospital, School of Medicine, Tongji University, Shanghai, China
| | - Yuanying Jiang
- Department of Pharmacy, Shanghai Tenth People’s Hospital, School of Medicine, Tongji University, Shanghai, China
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2
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Watchaputi K, Jayasekara LACB, Ratanakhanokchai K, Soontorngun N. Inhibition of cell cycle-dependent hyphal and biofilm formation by a novel cytochalasin 19,20‑epoxycytochalasin Q in Candida albicans. Sci Rep 2023; 13:9724. [PMID: 37322086 PMCID: PMC10272203 DOI: 10.1038/s41598-023-36191-4] [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: 03/28/2023] [Accepted: 05/30/2023] [Indexed: 06/17/2023] Open
Abstract
Biofilm-mediated drug resistance is a key virulence factor of pathogenic microbes that cause a serious global health threat especially in immunocompromised individuals. Here, we investigated the antihyphal and antibiofilm activity of 19,20‑epoxycytochalasin Q (ECQ), a cytochalasin actin inhibitor isolated from medicinal mushroom Xylaria sp. BCC1067 against Candida albicans. Remarkably, 256 µg/ml of ECQ inhibited over 95% of C. albicans hyphal formation after 24 h-treatment. Combined ECQ and lipid-based biosurfactant effectively enhanced the antihyphal activity, lowering required ECQ concentrations. Hyphal fragmentation and reduction of biofilm biomass, shown by SEM and AFM visualization of ECQ-treated biofilms, were well corelated to the reduced metabolic activities of young and 24 h-preformed C. albicans biofilms. Induced intracellular accumulation of reactive oxygen species (ROS) also occurred in accompany with the leakage of shrunken cell membrane and defective cell wall at increasing ECQ concentrations. Transcriptomic analyses via RNA-sequencing revealed a massive change (> 1300 genes) in various biological pathways, following ECQ-treatment. Coordinated expression of genes, associated with cellular response to drugs, filamentous growth, cell adhesion, biofilm formation, cytoskeleton organization, cell division cycle, lipid and cell wall metabolisms was confirmed via qRT-PCR. Protein-protein association tool identified coupled expression between key regulators of cell division cyclin-dependent kinases (Cdc19/28) and a gamma-tubulin (Tub4). They coordinated ECQ-dependent hyphal specific gene targets of Ume6 and Tec1 during different phases of cell division. Thus, we first highlight the antihyphal and antibiofilm property of the novel antifungal agent ECQ against one of the most important life-threatening fungal pathogens by providing its key mechanistic detail in biofilm-related fungal infection.
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Affiliation(s)
- Kwanrutai Watchaputi
- Excellent Research Laboratory for Yeast Innovation, Division of Biochemical Technology, School of Bioresources and Technology, King Mongkut's University of Technology Thonburi (KMUTT), Bangkok, 10150, Thailand
| | - L A Channa Bhathiya Jayasekara
- Excellent Research Laboratory for Yeast Innovation, Division of Biochemical Technology, School of Bioresources and Technology, King Mongkut's University of Technology Thonburi (KMUTT), Bangkok, 10150, Thailand
| | - Khanok Ratanakhanokchai
- Excellent Center of Enzyme Technology and Microbial Utilization, Pilot Plant Development and Training Institute, King Mongkut's University of Technology Thonburi (KMUTT), Bangkok, 10150, Thailand
| | - Nitnipa Soontorngun
- Excellent Research Laboratory for Yeast Innovation, Division of Biochemical Technology, School of Bioresources and Technology, King Mongkut's University of Technology Thonburi (KMUTT), Bangkok, 10150, Thailand.
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Martorano-Fernandes L, Goodwine JS, Ricomini-Filho AP, Nobile CJ, Del Bel Cury AA. Candida albicans Adhesins Als1 and Hwp1 Modulate Interactions with Streptococcus mutans. Microorganisms 2023; 11:1391. [PMID: 37374893 DOI: 10.3390/microorganisms11061391] [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: 03/22/2023] [Revised: 05/17/2023] [Accepted: 05/23/2023] [Indexed: 06/29/2023] Open
Abstract
Candida albicans and Streptococcus mutans are known to synergistically interact with each other in the oral cavity. For example, glucosyltransferase B (GtfB), secreted by S. mutans, can bind to the C. albicans cell surface, promoting dual-species biofilm formation. However, the fungal factors mediating interactions with S. mutans are unknown. The C. albicans adhesins Als1, Als3, and Hwp1 are key players in C. albicans single-species biofilm formation, but their roles, if any, in interacting with S. mutans have not been assessed. Here, we investigated the roles of the C. albicans cell wall adhesins Als1, Als3, and Hwp1 on forming dual-species biofilms with S. mutans. We assessed the abilities of the C. albicans wild-type als1Δ/Δ, als3Δ/Δ, als1Δ/Δ/als3Δ/Δ, and hwp1Δ/Δ strains to form dual-species biofilms with S. mutans by measuring optical density, metabolic activity, cell enumeration, biomass, thickness, and architecture of the biofilms. We observed that the C. albicans wild-type strain formed enhanced dual-species biofilms in the presence of S. mutans in these different biofilm assays, confirming that C. albicans and S. mutans synergistically interact in the context of biofilms. Our results reveal that C. albicans Als1 and Hwp1 are major players in interacting with S. mutans, since dual-species biofilm formation was not enhanced when the als1Δ/Δ or hwp1Δ/Δ strains were cultured with S. mutans in dual-species biofilms. Als3, however, does not seem to play a clear role in interacting with S. mutans in dual-species biofilm formation. Overall, our data suggest that the C. albicans adhesins Als1 and Hwp1 function to modulate interactions with S. mutans and could be potential targets for future therapeutics.
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Affiliation(s)
- Loyse Martorano-Fernandes
- Department of Prosthodontics and Periodontology, Piracicaba Dental School, University of Campinas (UNICAMP), Piracicaba 13414-903, SP, Brazil
- Department of Molecular and Cell Biology, School of Natural Sciences, University of California Merced, Merced, CA 95343, USA
| | - James S Goodwine
- Department of Molecular and Cell Biology, School of Natural Sciences, University of California Merced, Merced, CA 95343, USA
| | - Antônio Pedro Ricomini-Filho
- Department of Physiological Science, Piracicaba Dental School, University of Campinas (UNICAMP), Piracicaba 13414-903, SP, Brazil
| | - Clarissa J Nobile
- Department of Molecular and Cell Biology, School of Natural Sciences, University of California Merced, Merced, CA 95343, USA
- Health Sciences Research Institute, University of California Merced, Merced, CA 95343, USA
| | - Altair Antoninha Del Bel Cury
- Department of Prosthodontics and Periodontology, Piracicaba Dental School, University of Campinas (UNICAMP), Piracicaba 13414-903, SP, Brazil
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Mohammadi F, Charkhchian M, Mirzadeh M. Phenotypic and genotypic characterization of virulence markers and antifungal susceptibility of oral Candida species from diabetic and non-diabetic hemodialysis patients. BMC Oral Health 2023; 23:261. [PMID: 37143002 PMCID: PMC10157964 DOI: 10.1186/s12903-023-02970-8] [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: 12/03/2022] [Accepted: 04/16/2023] [Indexed: 05/06/2023] Open
Abstract
BACKGROUND Patients with chronic kidney disease undergoing hemodialysis are often colonized by Candida species with high possibility of fungal infections. The purposes of this study were to determine the prevalence of Candida species, evaluate antifungal susceptibility profile, biofilm formation, proteinase and phospholipase activities, and the frequency of virulence genes in the Candida species isolated from the oral mucosa of hemodialysis diabetic (DM) and non-diabetic (non-DM) patients. METHODS This study identified several species of Candida isolated from 69 DM and 58 non-DM patients on hemodialysis using phenotypic methods and PCR-RFLP technique. The identification of C. albicans and C. glabrata complex was performed by HWP1 gene and four oligonucleotides (UNI-5.8S, GLA-f, BRA-f, and NIV-f), respectively. Antifungal susceptibility to amphotericin B, fluconazole, itraconazole, voriconazole, and caspofungin was assessed according to CLSI M27-A3/S4. The biomass, metabolic activity of biofilm, proteinase (Prz), phospholipase (Pz), and molecular study for virulence genes were assessed using crystal violet, XTT assay, agar-based hydrolytic enzyme, and PCR technique, respectively. RESULTS Candida prevalence was 44.9% with 47.8% and 41.4% among DM and non-DM patients, respectively (P = .045). The species identified were C. albicans (49.5%), C. glabrata (16.5%), C. tropicalis (12%), C. kefyr (8.8%), C. parapsilosis (6.6%), C. dubliniensis (3.3%), and C. lusitaniae (3.3%). The antifungal susceptibility profile showed that all Candida isolates were sensitive to amphotericin B, itraconazole, voriconazole, and caspofungin whereas fluconazole resistance was observed in 6.3% (MIC ≥ 64 μg/mL) of C. albicans and 6.6% of C. glabrata (MIC ≥ 64 μg/mL). The susceptible- dose-dependent rate was found in 10.5% of C. albicans. The Prz values of C. albicans ranged from 0.37 to 0.66 for the DM and 0.44-0.73 for the non-DM group (P < 0.05). The non-albicans Candida (NAC) species produced higher degree of biomass and metabolic activity compared to C. albicans (P < 0.05). Furthermore, significant (p < 0.05) correlations were detected between the biofilm formation with Prz values and fluconazole MICs. The most detected virulence factors were ALS3 and Sap5. CONCLUSIONS These results showed the importance of prevalence of NAC species in hemodialysis patients. Investigating antifungal susceptibility profile made a better understanding of the role of virulence markers in the pathogenesis of Candida strains.
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Affiliation(s)
- Faezeh Mohammadi
- Medical Microbiology Research Center, Qazvin University of Medical Sciences, Qazvin, Iran.
- Department of Medical Parasitology and Mycology, School of Medicine, Qazvin University of Medical Sciences, Qazvin, Iran.
| | - Maliheh Charkhchian
- Metabolic Diseases Research Center, Research Institute for Prevention of Non-Communicable Diseases, Qazvin University of Medical Sciences, Qazvin, Iran
| | - Monirsadat Mirzadeh
- Metabolic Diseases Research Center, Research Institute for Prevention of Non-Communicable Diseases, Qazvin University of Medical Sciences, Qazvin, Iran
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Lipke PN, Ragonis-Bachar P. Sticking to the Subject: Multifunctionality in Microbial Adhesins. J Fungi (Basel) 2023; 9:jof9040419. [PMID: 37108873 PMCID: PMC10144551 DOI: 10.3390/jof9040419] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2023] [Revised: 03/25/2023] [Accepted: 03/27/2023] [Indexed: 03/31/2023] Open
Abstract
Bacterial and fungal adhesins mediate microbial aggregation, biofilm formation, and adhesion to host. We divide these proteins into two major classes: professional adhesins and moonlighting adhesins that have a non-adhesive activity that is evolutionarily conserved. A fundamental difference between the two classes is the dissociation rate. Whereas moonlighters, including cytoplasmic enzymes and chaperones, can bind with high affinity, they usually dissociate quickly. Professional adhesins often have unusually long dissociation rates: minutes or hours. Each adhesin has at least three activities: cell surface association, binding to a ligand or adhesive partner protein, and as a microbial surface pattern for host recognition. We briefly discuss Bacillus subtilis TasA, pilin adhesins, gram positive MSCRAMMs, and yeast mating adhesins, lectins and flocculins, and Candida Awp and Als families. For these professional adhesins, multiple activities include binding to diverse ligands and binding partners, assembly into molecular complexes, maintenance of cell wall integrity, signaling for cellular differentiation in biofilms and in mating, surface amyloid formation, and anchorage of moonlighting adhesins. We summarize the structural features that lead to these diverse activities. We conclude that adhesins resemble other proteins with multiple activities, but they have unique structural features to facilitate multifunctionality.
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Affiliation(s)
- Peter N. Lipke
- Biology Department, Brooklyn College of the City University of New York, Brooklyn, NY 11215, USA
- Correspondence:
| | - Peleg Ragonis-Bachar
- Department of Biology, Technion-Israel Institute of Technology, Haifa 3200003, Israel
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Oh SH, Martin-Yken H, Coleman DA, Dague E, Hoyer LL. Development and Use of a Monoclonal Antibody Specific for the Candida albicans Cell-Surface Protein Hwp1. Front Cell Infect Microbiol 2022; 12:907453. [PMID: 35832385 PMCID: PMC9273023 DOI: 10.3389/fcimb.2022.907453] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2022] [Accepted: 05/20/2022] [Indexed: 12/04/2022] Open
Abstract
The Candida albicans cell-surface protein Hwp1 functions in adhesion to the host and in biofilm formation. A peptide from the Gln-Pro-rich adhesive domain of Hwp1 was used to raise monoclonal antibody (MAb) 2-E8. MAb 2-E8 specificity for Hwp1 was demonstrated using a hwp1/hwp1 C. albicans isolate and strains that expressed at least one HWP1 allele. Immunofluorescence and atomic force microscopy experiments using MAb 2-E8 confirmed C. albicans germ-tube-specific detection of the Hwp1 protein. MAb 2-E8 also immunolabeled the tips of some Candida dubliniensis germ tubes grown under conditions that maximized HWP1 expression. The phylogeny of HWP1 and closely related genes suggested that the Gln-Pro-rich adhesive domain was unique to C. albicans and C. dubliniensis focusing the utility of MAb 2-E8 on these species. This new reagent can be used to address unanswered questions about Hwp1 and its interactions with other proteins in the context of C. albicans biology and pathogenesis.
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Affiliation(s)
- Soon-Hwan Oh
- Department of Pathobiology, University of Illinois at Urbana-Champaign, Urbana, IL, United States
| | - Hélène Martin-Yken
- Toulouse Biotechnology Institute, Université de Toulouse, CNRS, INRAE, INSA, Toulouse, France
- LAAS-CNRS, Université de Toulouse, CNRS, Toulouse, France
| | - David A. Coleman
- Department of Pathobiology, University of Illinois at Urbana-Champaign, Urbana, IL, United States
| | - Etienne Dague
- LAAS-CNRS, Université de Toulouse, CNRS, Toulouse, France
| | - Lois L. Hoyer
- Department of Pathobiology, University of Illinois at Urbana-Champaign, Urbana, IL, United States
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Hamida RS, Ali MA, Goda DA, Redhwan A. Anticandidal Potential of Two Cyanobacteria-Synthesized Silver Nanoparticles: Effects on Growth, Cell Morphology, and Key Virulence Attributes of Candida albicans. Pharmaceutics 2021; 13:1688. [PMID: 34683981 PMCID: PMC8539685 DOI: 10.3390/pharmaceutics13101688] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2021] [Revised: 10/06/2021] [Accepted: 10/08/2021] [Indexed: 01/06/2023] Open
Abstract
Candida albicans is an opportunistic human fungal pathogen responsible for 90-100% of mucosal and nosocomial infections worldwide. The emergence of drug-resistant strains has resulted in adverse consequences for human health, including numerous deaths. Consequently, there is an urgent need to identify and develop new antimicrobial drugs to counter these effects. Antimicrobial nanoagents have shown potent inhibitory activity against a number of pathogens through targeting their defense systems, such as biofilm formation. Here, we investigated the anticandidal activity of silver nanoparticles biosynthesized by the cyanobacterial strains Desertifilum sp. IPPAS B-1220 and Nostoc Bahar_M (D-SNPs and N-SNPs, respectively), along with that of silver nitrate (AgNO3), and examined the mechanisms underlying their lethal effects. For this, we performed agar well diffusion and enzyme activity assays (lactate dehydrogenase, adenosine triphosphatase, glutathione peroxidase, and catalase) and undertook morphological examinations using transmission electron microscopy. The effects of the three treatments on Hwp1 and CDR1 gene expression and protein patterns were assessed using qRT-PCR and SDS-PAGE assays, respectively. All of the three treatments inhibited C. albicans growth; disrupted membrane integrity, metabolic function, and antioxidant activity; induced ultrastructural changes in the cell envelope; and disrupted cytoplasmic and nuclear contents. Of the three agents, D-SNPs showed the greatest biocidal activity against C. albicans. Additionally, the D-SNP treatment significantly reduced the gene expression of Hwp1 and CDR1, suggestive of negative effects on biofilm formation ability and resistance potential of C. albicans, and promoted protein degradation. The mechanism involved in the biocidal effects of both D-SNPs and N-SNPs against C. albicans could be attributed to their ability to interfere with fungal cell structures and/or stimulate oxidative stress, enabling them to be used as a robust antimycotic agent.
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Affiliation(s)
- Reham Samir Hamida
- Molecular Biology Unit, Department of Zoology, Faculty of Science, Alexandria University, Alexandria 21500, Egypt;
| | - Mohamed Abdelaal Ali
- Biotechnology Unit, Department of Plant Production, College of Food and Agriculture Science, King Saud University, Riyadh 12372, Saudi Arabia;
| | - Doaa A. Goda
- Bioprocess Development Department, Genetic Engineering and Biotechnology Research Institute (GEBRI), City of Scientific Research and Technological Applications (SRTA-City), Alexandria 21934, Egypt;
| | - Alya Redhwan
- Department of Health, College of Health and Rehabilitation Sciences, Princess Nourah bint Abdulrahman University, Riyadh 11564, Saudi Arabia
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Analysis of Biofilm-Related Genes and Antifungal Susceptibility Pattern of Vaginal Candida albicans and Non- Candida albicans Species. BIOMED RESEARCH INTERNATIONAL 2021; 2021:5598907. [PMID: 34136569 PMCID: PMC8179781 DOI: 10.1155/2021/5598907] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/14/2021] [Accepted: 05/16/2021] [Indexed: 01/12/2023]
Abstract
Background Vulvovaginal candidiasis caused by Candida species is a prevalent fungal infection among women. It is believed that the pathogenesis of Candida species is linked with the production of biofilm which is considered a virulence factor for this organism. The aim of this study was molecular identification, antifungal susceptibility, biomass quantification of biofilm, and detection of virulence markers of Candida species. Methods We investigated the molecular identification of 70 vaginal isolates of Candida species, antifungal resistance to amphotericin B, fluconazole, itraconazole, and voriconazole according to CLSI M27-A3 and M27-S4, biofilm formation, and frequency analysis of biofilm-related ALS1, ALS3, and HWP1 genes. Results Our findings showed that the most common yeast isolated from vaginal discharge was C. albicans (67%), followed by the non-Candida albicans species (33%). All C. albicans complex isolates were confirmed as C. albicans by HWP-PCR, and all isolates of the C. glabrata complex were revealed to be C. glabrata sensu stricto using the multiplex PCR method. FLC resistance was observed in 23.4% of C. albicans and 7.7% of C. glabrata. The resistance rate to ITC was found in 10.6% of C. albicans. The frequency of ALS1, ALS3, and HWP1 genes among Candida species was 67.1%, 80%, and 81.4%, respectively. Biofilm formation was observed in 54.3% of Candida species, and the highest frequency detected as a virulence factor was for the ALS3 gene (97.3%) in biofilm-forming species. Discussion. Our results showed the importance of molecular epidemiology studies, investigating antifungal susceptibility profiles, and understanding the role of biofilm-related virulence markers in the pathogenesis of Candida strains.
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Moreno-Martínez AE, Gómez-Molero E, Sánchez-Virosta P, Dekker HL, de Boer A, Eraso E, Bader O, de Groot PWJ. High Biofilm Formation of Non-Smooth Candida parapsilosis Correlates with Increased Incorporation of GPI-Modified Wall Adhesins. Pathogens 2021; 10:pathogens10040493. [PMID: 33921809 PMCID: PMC8073168 DOI: 10.3390/pathogens10040493] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2021] [Revised: 04/15/2021] [Accepted: 04/16/2021] [Indexed: 11/16/2022] Open
Abstract
Candida parapsilosis is among the most frequent causes of candidiasis. Clinical isolates of this species show large variations in colony morphotype, ranging from round and smooth to a variety of non-smooth irregular colony shapes. A non-smooth appearance is related to increased formation of pseudohyphae, higher capacity to form biofilms on abiotic surfaces, and invading agar. Here, we present a comprehensive study of the cell wall proteome of C. parapsilosis reference strain CDC317 and seven clinical isolates under planktonic and sessile conditions. This analysis resulted in the identification of 40 wall proteins, most of them homologs of known Candida albicans cell wall proteins, such as Gas, Crh, Bgl2, Cht2, Ecm33, Sap, Sod, Plb, Pir, Pga30, Pga59, and adhesin family members. Comparative analysis of exponentially growing and stationary phase planktonic cultures of CDC317 at 30 °C and 37 °C revealed only minor variations. However, comparison of smooth isolates to non-smooth isolates with high biofilm formation capacity showed an increase in abundance and diversity of putative wall adhesins from Als, Iff/Hyr, and Hwp families in the latter. This difference depended more strongly on strain phenotype than on the growth conditions, as it was observed in planktonic as well as biofilm cells. Thus, in the set of isolates analyzed, the high biofilm formation capacity of non-smooth C. parapsilosis isolates with elongated cellular phenotypes correlates with the increased surface expression of putative wall adhesins in accordance with their proposed cellular function.
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Affiliation(s)
- Ana Esther Moreno-Martínez
- Albacete Regional Center for Biomedical Research, Castilla—La Mancha Science & Technology Park, University of Castilla-La Mancha, 02008 Albacete, Spain; (A.E.M.-M.); (E.G.-M.); (P.S.-V.); (A.d.B.)
| | - Emilia Gómez-Molero
- Albacete Regional Center for Biomedical Research, Castilla—La Mancha Science & Technology Park, University of Castilla-La Mancha, 02008 Albacete, Spain; (A.E.M.-M.); (E.G.-M.); (P.S.-V.); (A.d.B.)
- Institute for Medical Microbiology, University Medical Center Göttingen, Kreuzbergring 57, 37075 Göttingen, Germany
| | - Pablo Sánchez-Virosta
- Albacete Regional Center for Biomedical Research, Castilla—La Mancha Science & Technology Park, University of Castilla-La Mancha, 02008 Albacete, Spain; (A.E.M.-M.); (E.G.-M.); (P.S.-V.); (A.d.B.)
| | - Henk L. Dekker
- Mass Spectrometry of Biomolecules, Swammerdam Institute for Life Sciences, University of Amsterdam, 1098 XH Amsterdam, The Netherlands;
| | - Albert de Boer
- Albacete Regional Center for Biomedical Research, Castilla—La Mancha Science & Technology Park, University of Castilla-La Mancha, 02008 Albacete, Spain; (A.E.M.-M.); (E.G.-M.); (P.S.-V.); (A.d.B.)
| | - Elena Eraso
- Department of Immunology, Microbiology and Parasitology, Faculty of Medicine and Nursing, University of the Basque Country (UPV/EHU), 48940 Bilbao, Spain;
| | - Oliver Bader
- Institute for Medical Microbiology, University Medical Center Göttingen, Kreuzbergring 57, 37075 Göttingen, Germany
- Correspondence: (O.B.); (P.W.J.d.G.)
| | - Piet W. J. de Groot
- Albacete Regional Center for Biomedical Research, Castilla—La Mancha Science & Technology Park, University of Castilla-La Mancha, 02008 Albacete, Spain; (A.E.M.-M.); (E.G.-M.); (P.S.-V.); (A.d.B.)
- Correspondence: (O.B.); (P.W.J.d.G.)
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Glodowsky AP, Ruberto LA, Martorell MM, Mac Cormack WP, Levin GJ. Cold active transglutaminase from antarctic Penicillium chrysogenum: Partial purification, characterization and potential application in food technology. BIOCATALYSIS AND AGRICULTURAL BIOTECHNOLOGY 2020. [DOI: 10.1016/j.bcab.2020.101807] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
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Aaron L, Torsten M. Candida albicans in celiac disease: A wolf in sheep's clothing. Autoimmun Rev 2020; 19:102621. [PMID: 32693029 DOI: 10.1016/j.autrev.2020.102621] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2020] [Accepted: 03/20/2020] [Indexed: 12/16/2022]
Abstract
Candida albicans is a commensal fungus with a potential pathogenicity and celiac disease is an autoimmune condition. Both share multiple pathophysiological junctions, including serological markers against cell-wall proteins of Candida, anti-gliadin antibodies are positive in both entities, gluten and a candidal virulence factor share sequence similarity and the autoantigen of celiac disease, the tissue transglutaminase, is pivotal in Candida albicans commensalism and hostile behavior and its covalently cross linked products are stable and resistant to breakdown in the two entities. Those autoimmune/infectious cross roads are the basis for the hypothesis that Candida albicans is an additional environmental factor for celiac disease autoimmunogenesis.
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Thomas G, Bain JM, Budge S, Brown AJP, Ames RM. Identifying Candida albicans Gene Networks Involved in Pathogenicity. Front Genet 2020; 11:375. [PMID: 32391057 PMCID: PMC7193023 DOI: 10.3389/fgene.2020.00375] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2020] [Accepted: 03/26/2020] [Indexed: 11/17/2022] Open
Abstract
Candida albicans is a normal member of the human microbiome. It is also an opportunistic pathogen, which can cause life-threatening systemic infections in severely immunocompromized individuals. Despite the availability of antifungal drugs, mortality rates of systemic infections are high and new drugs are needed to overcome therapeutic challenges including the emergence of drug resistance. Targeting known disease pathways has been suggested as a promising avenue for the development of new antifungals. However, <30% of C. albicans genes are verified with experimental evidence of a gene product, and the full complement of genes involved in important disease processes is currently unknown. Tools to predict the function of partially or uncharacterized genes and generate testable hypotheses will, therefore, help to identify potential targets for new antifungal development. Here, we employ a network-extracted ontology to leverage publicly available transcriptomics data and identify potential candidate genes involved in disease processes. A subset of these genes has been phenotypically screened using available deletion strains and we present preliminary data that one candidate, PEP8, is involved in hyphal development and immune evasion. This work demonstrates the utility of network-extracted ontologies in predicting gene function to generate testable hypotheses that can be applied to pathogenic systems. This could represent a novel first step to identifying targets for new antifungal therapies.
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Affiliation(s)
- Graham Thomas
- Biosciences, University of Exeter, Exeter, United Kingdom
| | - Judith M Bain
- Aberdeen Fungal Group, Institute of Medical Sciences, University of Aberdeen, Aberdeen, United Kingdom
| | - Susan Budge
- Aberdeen Fungal Group, Institute of Medical Sciences, University of Aberdeen, Aberdeen, United Kingdom
| | - Alistair J P Brown
- Aberdeen Fungal Group, Institute of Medical Sciences, University of Aberdeen, Aberdeen, United Kingdom.,MRC Centre for Medical Mycology at the University of Exeter, Biosciences, University of Exeter, Exeter, United Kingdom
| | - Ryan M Ames
- Biosciences, University of Exeter, Exeter, United Kingdom
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Partner Choice in Spontaneous Mitotic Recombination in Wild Type and Homologous Recombination Mutants of Candida albicans. G3-GENES GENOMES GENETICS 2019; 9:3631-3644. [PMID: 31690596 PMCID: PMC6829120 DOI: 10.1534/g3.119.400516] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
Candida albicans, the most common fungal pathogen, is a diploid with a genome that is rich in repeats and has high levels of heterozygosity. To study the role of different recombination pathways on direct-repeat recombination, we replaced either allele of the RAD52 gene (Chr6) with the URA-blaster cassette (hisG-URA3-hisG), measured rates of URA3 loss as resistance to 5-fluoroorotic acid (5FOAR) and used CHEF Southern hybridization and SNP-RFLP analysis to identify recombination mechanisms and their frequency in wildtype and recombination mutants. FOAR rates varied little across different strain backgrounds. In contrast, the type and frequency of mechanisms underlying direct repeat recombination varied greatly. For example, wildtype, rad59 and lig4 strains all displayed a bias for URA3 loss via pop-out/deletion vs. inter-homolog recombination and this bias was reduced in rad51 mutants. In addition, in rad51-derived 5FOAR strains direct repeat recombination was associated with ectopic translocation (5%), chromosome loss/truncation (14%) and inter-homolog recombination (6%). In the absence of RAD52, URA3 loss was mostly due to chromosome loss and truncation (80–90%), and the bias of retained allele frequency points to the presence of a recessive lethal allele on Chr6B. However, a few single-strand annealing (SSA)-like events were identified and these were independent of either Rad59 or Lig4. Finally, the specific sizes of Chr6 truncations suggest that the inserted URA-blaster could represent a fragile site.
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Candida albicans Interactions with Mucosal Surfaces during Health and Disease. Pathogens 2019; 8:pathogens8020053. [PMID: 31013590 PMCID: PMC6631630 DOI: 10.3390/pathogens8020053] [Citation(s) in RCA: 50] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2019] [Revised: 04/05/2019] [Accepted: 04/15/2019] [Indexed: 12/20/2022] Open
Abstract
Flexible adaptation to the host environment is a critical trait that underpins the success of numerous microbes. The polymorphic fungus Candida albicans has evolved to persist in the numerous challenging niches of the human body. The interaction of C. albicans with a mucosal surface is an essential prerequisite for fungal colonisation and epitomises the complex interface between microbe and host. C. albicans exhibits numerous adaptations to a healthy host that permit commensal colonisation of mucosal surfaces without provoking an overt immune response that may lead to clearance. Conversely, fungal adaptation to impaired immune fitness at mucosal surfaces enables pathogenic infiltration into underlying tissues, often with devastating consequences. This review will summarise our current understanding of the complex interactions that occur between C. albicans and the mucosal surfaces of the human body.
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15
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Willaert RG. Adhesins of Yeasts: Protein Structure and Interactions. J Fungi (Basel) 2018; 4:jof4040119. [PMID: 30373267 PMCID: PMC6308950 DOI: 10.3390/jof4040119] [Citation(s) in RCA: 50] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2018] [Revised: 10/23/2018] [Accepted: 10/24/2018] [Indexed: 12/14/2022] Open
Abstract
The ability of yeast cells to adhere to other cells or substrates is crucial for many yeasts. The budding yeast Saccharomyces cerevisiae can switch from a unicellular lifestyle to a multicellular one. A crucial step in multicellular lifestyle adaptation is self-recognition, self-interaction, and adhesion to abiotic surfaces. Infectious yeast diseases such as candidiasis are initiated by the adhesion of the yeast cells to host cells. Adhesion is accomplished by adhesin proteins that are attached to the cell wall and stick out to interact with other cells or substrates. Protein structures give detailed insights into the molecular mechanism of adhesin-ligand interaction. Currently, only the structures of a very limited number of N-terminal adhesion domains of adhesins have been solved. Therefore, this review focuses on these adhesin protein families. The protein architectures, protein structures, and ligand interactions of the flocculation protein family of S. cerevisiae; the epithelial adhesion family of C. glabrata; and the agglutinin-like sequence protein family of C. albicans are reviewed and discussed.
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Affiliation(s)
- Ronnie G Willaert
- Alliance Research Group VUB-UGent NanoMicrobiology (NAMI), IJRG VUB-EPFL NanoBiotechnology & NanoMedicine (NANO), Research Group Structural Biology Brussels, Vrije Universiteit Brussel, 1050 Brussels, Belgium.
- Department Bioscience Engineering, University Antwerp, 2020 Antwerp, Belgium.
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16
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Novel Formulated Zinc Oxide Nanoparticles Reduce Hwp1 Gene Expression Involved in Biofilm Formation in Candida albicans with Minimum Cytotoxicity Effect on Human Cells. Jundishapur J Microbiol 2018. [DOI: 10.5812/jjm.79562] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
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17
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Sundararajan A, Rane HS, Ramaraj T, Sena J, Howell AB, Bernardo SM, Schilkey FD, Lee SA. Cranberry-derived proanthocyanidins induce a differential transcriptomic response within Candida albicans urinary biofilms. PLoS One 2018; 13:e0201969. [PMID: 30089157 PMCID: PMC6082538 DOI: 10.1371/journal.pone.0201969] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2018] [Accepted: 07/25/2018] [Indexed: 11/18/2022] Open
Abstract
Candida albicans is one of the most common causes of hospital-acquired urinary tract infections (UTIs). However, azoles are poorly active against biofilms, echinocandins do not achieve clinically useful urinary concentrations, and amphotericin B exhibits severe toxicities. Thus, novel strategies are needed to prevent Candida UTIs, which are often associated with urinary catheter biofilms. We previously demonstrated that cranberry-derived proanthocyanidins (PACs) prevent C. albicans biofilm formation in an in vitro urinary model. To elucidate functional pathways unique to urinary biofilm development and PAC inhibition, we investigated the transcriptome of C. albicans in artificial urine (AU), with and without PACs. C. albicans biofilm and planktonic cells were cultivated with or without PACs. Genome-wide expression analysis was performed by RNA sequencing. Differentially expressed genes were determined using DESeq2 software; pathway analysis was performed using Cytoscape. Approximately 2,341 of 6,444 total genes were significantly expressed in biofilm relative to planktonic cells. Functional pathway analysis revealed that genes involved in filamentation, adhesion, drug response and transport were up-regulated in urinary biofilms. Genes involved in carbon and nitrogen metabolism and nutrient response were down-regulated. In PAC-treated urinary biofilms compared to untreated control biofilms, 557 of 6,444 genes had significant changes in gene expression. Genes downregulated in PAC-treated biofilms were implicated in iron starvation and adhesion pathways. Although urinary biofilms share key features with biofilms formed in other environments, many genes are uniquely expressed in urinary biofilms. Cranberry-derived PACs interfere with the expression of iron acquisition and adhesion genes within urinary biofilms.
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Affiliation(s)
- Anitha Sundararajan
- National Center for Genome Resources, Santa Fe, NM, United States of America
| | - Hallie S. Rane
- Section of Infectious Diseases, New Mexico VA Healthcare System, Albuquerque, NM, United States of America
| | | | - Johnny Sena
- National Center for Genome Resources, Santa Fe, NM, United States of America
| | - Amy B. Howell
- Marucci Center for Blueberry and Cranberry Research and Extension, Rutgers, The State University of New Jersey, Chatsworth, NJ, United States of America
| | - Stella M. Bernardo
- Division of Infectious Diseases, University of New Mexico Health Science Center, Albuquerque, NM, United States of America
| | - Faye D. Schilkey
- National Center for Genome Resources, Santa Fe, NM, United States of America
| | - Samuel A. Lee
- Section of Infectious Diseases, New Mexico VA Healthcare System, Albuquerque, NM, United States of America
- Division of Infectious Diseases, University of New Mexico Health Science Center, Albuquerque, NM, United States of America
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18
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Biological Roles of Protein-Coding Tandem Repeats in the Yeast Candida Albicans. J Fungi (Basel) 2018; 4:jof4030078. [PMID: 29966250 PMCID: PMC6162428 DOI: 10.3390/jof4030078] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2018] [Revised: 06/16/2018] [Accepted: 06/27/2018] [Indexed: 01/07/2023] Open
Abstract
Tandem repeat (TR) DNA mutates faster than other DNA by insertion and deletion of repeats. Large parts of eukaryotic proteomes are encoded by ORFs containing protein-coding TRs (TR-ORFs, pcTRs) with largely unknown biological consequences. We explored these in the yeast Candida albicans, an opportunistic human pathogen. We found that almost half of C. albicans’ proteins are encoded by TR-ORFs. pcTR frequency differed only moderately between different gene (GO) categories. Bioinformatic predictions of genome-wide mutation rates and clade-specific differences in pcTR allele frequencies indicated that pcTRs (i) significantly increase the genome-wide mutation rate; (ii) significantly impact on fitness and (iii) allow the evolution of selectively advantageous clade-specific protein variants. Synonymous mutations reduced the repetitiveness of many amino acid repeat-encoding pcTRs. A survey, in 58 strains, revealed that in some pcTR regions in which repetitiveness was not significantly diminished by synonymous mutations the habitat predicted which alleles were present, suggesting roles of pcTR mutation in short-term adaptation and pathogenesis. In C. albicans pcTR mutation apparently is an important mechanism for mutational advance and possibly also rapid adaptation, with synonymous mutations providing a mechanism for adjusting mutation rates of individual pcTRs. Analyses of Arabidopsis and human pcTRs showed that the latter also occurs in other eukaryotes.
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19
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Lipke PN. What We Do Not Know about Fungal Cell Adhesion Molecules. J Fungi (Basel) 2018; 4:jof4020059. [PMID: 29772751 PMCID: PMC6023273 DOI: 10.3390/jof4020059] [Citation(s) in RCA: 51] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2018] [Revised: 04/27/2018] [Accepted: 05/10/2018] [Indexed: 12/16/2022] Open
Abstract
There has been extensive research on structure and function of fungal cell adhesion molecules, but the most of the work has been about adhesins in Candida albicans and Saccharomyces cerevisiae. These yeasts are members of a single ascomycete order, and adhesion molecules from the six other fungal phyla are only sparsely described in the literature. In these other phyla, most of the research is at the cellular level, rather than at the molecular level, so there has been little characterization of the adhesion molecules themselves. A catalog of known adhesins shows some common features: high Ser/Thr content, tandem repeats, N- and O-glycosylations, GPI anchors, dibasic sequence motifs, and potential amyloid-forming sequences. However, none of these features is universal. Known ligands include proteins and glycans on homologous cells and host cells. Existing and novel tools can exploit the availability of genome sequences to identify and characterize new fungal adhesins. These include bioinformatics tools and well-established yeast surface display models, which could be coupled with an adhesion substrate array. Thus, new knowledge could be exploited to answer key questions in fungal ecology, animal and plant pathogenesis, and roles of biofilms in infection and biomass turnover.
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Affiliation(s)
- Peter N Lipke
- Biology Department, Brooklyn College, City University of New York, Brooklyn, NY 11210, USA.
- The Graduate Center, City University of New York, New York, NY 10016, USA.
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20
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Kim S, Nguyen QB, Wolyniak MJ, Frechette G, Lehman CR, Fox BK, Sundstrom P. Release of transcriptional repression through the HCR promoter region confers uniform expression of HWP1 on surfaces of Candida albicans germ tubes. PLoS One 2018; 13:e0192260. [PMID: 29438403 PMCID: PMC5810986 DOI: 10.1371/journal.pone.0192260] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2017] [Accepted: 01/19/2018] [Indexed: 12/31/2022] Open
Abstract
The mechanisms that fungi use to co-regulate subsets of genes specifically associated with morphogenic states represent a basic unsolved problem in fungal biology. Candida albicans is an important model of fungal differentiation both for rapid interconversion between yeast and hyphal growth forms and for white/opaque switching mechanisms. The Sundstrom lab is interested in mechanisms regulating hypha-specific expression of adhesin genes that are critical for C. albicans hyphal growth phenotypes and pathogenicity. Early studies on hypha-specific genes such as HWP1 and ALS3 reported 5’ intergenic regions that are larger than those typically found in an average promoter and are associated with hypha-specific expression. In the case of HWP1, activation and repression involves a 368 bp region, denoted the HWP1 control region (HCR), located 1410 bp upstream of its transcription start site. In previous work we showed that HCR confers developmental regulation to a heterologous ENO1 promoter, indicating that HCR by itself contains sufficient information to couple gene expression to morphology. Here we show that the activation and repression mediated by HCR are localized to distinct HCR regions that are targeted by the transcription factors Nrg1p and Efg1p. The finding that Efg1p mediates both repression via HCR under yeast morphological conditions and activation conditions positions Efg1p as playing a central role in coupling HWP1 expression to morphogenesis through the HCR region. These localization studies revealed that the 120 terminal base pairs of HCR confer Efg1p-dependent repressive activity in addition to the Nrg1p repressive activity mediated by DNA upstream of this subregion. The 120 terminal base pair subregion of HCR also contained an initiation site for an HWP1 transcript that is specific to yeast growth conditions (HCR-Y) and may function in the repression of downstream DNA. The detection of an HWP1 mRNA isoform specific to hyphal growth conditions (HWP1-H) showed that morphology-specific mRNA isoforms occur under both yeast and hyphal growth conditions. Similar results were found at the ALS3 locus. Taken together, these results, suggest that the long 5’ intergenic regions upstream of hypha-specific genes function in generating mRNA isoforms that are important for morphology-specific gene expression. Additional complexity in the HWP1 promoter involving HCR-independent activation was discovered by creating a strain lacking HCR that exhibited variable HWP1 expression during hyphal growth conditions. These results show that while HCR is important for ensuring uniform HWP1 expression in cell populations, HCR independent expression also exists. Overall, these results elucidate HCR-dependent mechanisms for coupling HWP1-dependent gene expression to morphology uniformly in cell populations and prompt the hypothesis that mRNA isoforms may play a role in coupling gene expression to morphology in C. albicans.
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Affiliation(s)
- Samin Kim
- Department of Microbiology and Immunology, Microbiology and Molecular Pathogenesis Program, Geisel School of Medicine at Dartmouth, Hanover, New Hampshire, United States of America
| | - Quoc Bao Nguyen
- Department of Microbiology and Immunology, Microbiology and Molecular Pathogenesis Program, Geisel School of Medicine at Dartmouth, Hanover, New Hampshire, United States of America
| | - Michael J. Wolyniak
- Department of Biology, Hampden-Sydney College, Hampden-Sydney, Virginia, United States of America
| | - Gregory Frechette
- Department of Microbiology and Immunology, Microbiology and Molecular Pathogenesis Program, Geisel School of Medicine at Dartmouth, Hanover, New Hampshire, United States of America
| | - Christian R. Lehman
- Department of Biology, Hampden-Sydney College, Hampden-Sydney, Virginia, United States of America
| | - Brandon K. Fox
- Department of Biology, Hampden-Sydney College, Hampden-Sydney, Virginia, United States of America
| | - Paula Sundstrom
- Department of Microbiology and Immunology, Microbiology and Molecular Pathogenesis Program, Geisel School of Medicine at Dartmouth, Hanover, New Hampshire, United States of America
- * E-mail:
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21
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Hall RA, Noverr MC. Fungal interactions with the human host: exploring the spectrum of symbiosis. Curr Opin Microbiol 2017; 40:58-64. [PMID: 29132066 DOI: 10.1016/j.mib.2017.10.020] [Citation(s) in RCA: 49] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2017] [Accepted: 10/24/2017] [Indexed: 12/14/2022]
Abstract
Fungi are ubiquitous transient or persistent human colonisers, and form the mycobiome with shifts in niche specific mycobiomes (dysbiosis) being associated with various diseases. These complex interactions of fungal species with the human host can be viewed as a spectrum of symbiotic relationships (i.e. commensal, parasitic, mutualistic, amensalistic). The host relevant outcome of the relationship is the damage to benefit ratio, elegantly described in the damage response framework. This review focuses on Candida albicans, which is the most well studied human fungal symbiont clinically and experimentally, its transition from commensalism to parasitism within the human host, and the factors that influence this relationship.
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Affiliation(s)
- Rebecca A Hall
- Institute of Microbiology and Infection, School of Biosciences, University of Birmingham, Birmingham, UK.
| | - Mairi C Noverr
- Department of Prosthodontics, Louisiana State University School of Dentistry, New Orleans, LA, USA
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22
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Mail MH, Himratul-Aznita WH, Musa MY. Anti-hyphal properties of potential bioactive compounds for oral rinse in suppression of Candidagrowth. BIOTECHNOL BIOTEC EQ 2017. [DOI: 10.1080/13102818.2017.1348255] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022] Open
Affiliation(s)
- Mohd Hafiz Mail
- Department of Oral and Craniofacial Sciences, Faculty of Dentistry, University of Malaya, Kuala Lumpur, Malaysia
| | - Wan Harun Himratul-Aznita
- Department of Oral and Craniofacial Sciences, Faculty of Dentistry, University of Malaya, Kuala Lumpur, Malaysia
| | - Md Yusoff Musa
- Institute of Biological Sciences, Faculty of Science, University of Malaya, Kuala Lumpur, Malaysia
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23
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Highly mutable tandem DNA repeats generate a cell wall protein variant more frequent in disease-causing Candida albicans isolates than in commensal isolates. PLoS One 2017; 12:e0180246. [PMID: 28662107 PMCID: PMC5491155 DOI: 10.1371/journal.pone.0180246] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2017] [Accepted: 06/12/2017] [Indexed: 11/19/2022] Open
Abstract
During adaptation to host environments, many microorganisms alter their cell surface. One mechanism for doing so is variation in the number of amino acid repeats in cell surface proteins encoded by hypermutable DNA tandem repeats. In the yeast Candida albicans, an opportunistic human pathogen, the gene SSR1 encodes a GPI-anchored cell wall protein with a structural role. It contains two regions consisting of tandem repeats, almost exclusively encoding the amino acid pair Ser-Ala. As expected, the repeat regions make SSR1 highly mutable. New SSR1 alleles arose with a frequency of 1.11×10−4 per cell division in serially propagated cells. We also observed a large number (25) of SSR1 alleles with different repeat lengths in a survey of 131 isolates from a global strain collection. C. albicans is diploid, and combinations of these allele generated 41 different SSR1 genotypes. In both repeat regions, nonsynonymous mutations were largely restricted to one particular repeat unit. Two very similar allele combinations were largely restricted to one clade, clade 1. Each combination was present in ~30% of 49 infection-causing clade 1 strains, but one was rare (2%), the other absent in 46 infection-causing strains representing the remainder of the species (P < 0.00018 and 0.00004; Fisher’s exact test). These results indicate that both repeat regions are under selection and that amino acid repeat length polymorphisms generate Ssr1 protein variants most suitable for specific genetic backgrounds. One of these two allele combinations was 5.51 times more frequent, the other 1.75 times less frequent in 49 clade 1 strains that caused disease than in 36 commensal clade 1 strains (P = 0.0105; Chi2 test). This indicates that insertion and deletion of repeats not only generates clade-optimized Ssr1p variants, but may also assist in short-term adaptation when C. albicans makes the transition from commensal to pathogen.
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24
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Román E, Correia I, Salazin A, Fradin C, Jouault T, Poulain D, Liu FT, Pla J. The Cek1‑mediated MAP kinase pathway regulates exposure of α‑1,2 and β‑1,2‑mannosides in the cell wall of Candida albicans modulating immune recognition. Virulence 2016; 7:558-77. [PMID: 27191378 DOI: 10.1080/21505594.2016.1163458] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
The Cek1 MAP kinase (MAPK) mediates vegetative growth and cell wall biogenesis in the fungal pathogen Candida albicans. Alterations in the fungal cell wall caused by a defective Cek1‑mediated signaling pathway leads to increased β‑1,3‑glucan exposure influencing dectin‑1 fungal recognition by immune cells. We show here that cek1 cells also display an increased exposure of α‑1,2 and β‑1,2‑mannosides (α‑M and β‑M), a phenotype shared by strains defective in the activating MAPKK Hst7, suggesting a general defect in cell wall assembly. cek1 cells display walls with loosely bound material as revealed by transmission electron microscopy and are sensitive to tunicamycin, an inhibitor of N‑glycosylation. Transcriptomal analysis of tunicamycin treated cells revealed a differential pattern between cek1 and wild type cells which involved mainly cell wall and stress related genes. Mapping α‑M and β‑M epitopes in the mannoproteins of different cell wall fractions (CWMP) revealed an important shift in the molecular weight of the mannan derived from mutants defective in this MAPK pathway. We have also assessed the role of galectin‑3, a member of a β‑galactoside‑binding protein family shown to bind to and kill C. albicans through β‑M recognition, in the infection caused by cek1 mutants. Increased binding of cek1 to murine macrophages was shown to be partially blocked by lactose. Galectin-3(-/-) mice showed increased resistance to fungal infection, although galectin-3 did not account for the reduced virulence of cek1 mutants in a mouse model of systemic infection. All these data support a role for the Cek1‑mediated pathway in fungal cell wall maintenance, virulence and antifungal discovery.
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Affiliation(s)
- E Román
- a Departamento de Microbiología II , Facultad de Farmacia, Universidad Complutense de Madrid , Madrid , Spain
| | - I Correia
- a Departamento de Microbiología II , Facultad de Farmacia, Universidad Complutense de Madrid , Madrid , Spain
| | - A Salazin
- b Univ. Lille, Inserm, CHU Lille, U995 - LIRIC - Lille Inflammation Research International Center , Lille , France
| | - C Fradin
- b Univ. Lille, Inserm, CHU Lille, U995 - LIRIC - Lille Inflammation Research International Center , Lille , France
| | - T Jouault
- b Univ. Lille, Inserm, CHU Lille, U995 - LIRIC - Lille Inflammation Research International Center , Lille , France
| | - D Poulain
- b Univ. Lille, Inserm, CHU Lille, U995 - LIRIC - Lille Inflammation Research International Center , Lille , France
| | - F-T Liu
- c Department of Dermatology , University of California, Davis, School of Medicine , Sacramento , CA , USA.,d Institute of Biomedical Sciences, Academia Sinica , Taipei , Taiwan
| | - J Pla
- a Departamento de Microbiología II , Facultad de Farmacia, Universidad Complutense de Madrid , Madrid , Spain
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25
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Moyes DL, Richardson JP, Naglik JR. Candida albicans-epithelial interactions and pathogenicity mechanisms: scratching the surface. Virulence 2016; 6:338-46. [PMID: 25714110 PMCID: PMC4601190 DOI: 10.1080/21505594.2015.1012981] [Citation(s) in RCA: 84] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
Until recently, epithelial cells have been a largely ignored component of host responses to microbes. However, this has been largely overturned over the last decade as an ever increasing number of studies have highlighted the key role that these cells play in many of our interactions with our microbiota and pathogens. Interactions of these cells with Candida albicans have been shown to be critical not just in host responses, but also in fungal cell responses, regulating fungal morphology and gene expression profile. In this review, we will explore the interactions between C. albicans and epithelial cells, and discuss how these interactions affect our relationship with this fungus.
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Affiliation(s)
- David L Moyes
- a Mucosal & Salivary Biology Division ; King's College London Dental Institute; King's College London ; London , UK
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26
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Höfs S, Mogavero S, Hube B. Interaction of Candida albicans with host cells: virulence factors, host defense, escape strategies, and the microbiota. J Microbiol 2016; 54:149-69. [DOI: 10.1007/s12275-016-5514-0] [Citation(s) in RCA: 115] [Impact Index Per Article: 14.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2015] [Revised: 11/03/2015] [Accepted: 11/07/2015] [Indexed: 12/20/2022]
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27
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Courjol F, Jouault T, Mille C, Hall R, Maes E, Sendid B, Mallet JM, Guerardel Y, Gow NAR, Poulain D, Fradin C. β-1,2-Mannosyltransferases 1 and 3 Participate in Yeast and Hyphae O- and N-Linked Mannosylation and Alter Candida albicans Fitness During Infection. Open Forum Infect Dis 2015; 2:ofv116. [PMID: 26389126 PMCID: PMC4564806 DOI: 10.1093/ofid/ofv116] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2015] [Accepted: 08/11/2015] [Indexed: 11/19/2022] Open
Abstract
β-1,2-mannosylation of Candida albicans glycoconjugates has been investigated through the identification of enzymes involved in the addition of β-1,2-oligomannosides (β-Mans) to phosphopeptidomannan and phospholipomannan. β-1,2-oligomannosides are supposed to have virulence properties that they confer to these glycoconjugates. In a previous study, we showed that cell wall mannoproteins (CWMPs) harbor β-Mans in their O-mannosides; therefore, we analyzed their biosynthesis and impact on virulence. In this study, we demonstrate that O-mannans are heterogeneous and that α-mannosylated O-mannosides, which are biosynthesized by Mnt1 and Mnt2 α-1,2-mannosyltransferases, can be modified with β-Mans but only at the nonreducing end of α-1,2-mannotriose. β-1,2-mannosylation of this O-mannotriose depends on growth conditions, and it involves 2 β-1,2-mannosyltransferases, Bmt1 and Bmt3. These Bmts are essential for β-1,2-mannosylation of CWMPs and expression of β-Mans on germ tubes. A bmt1Δ mutant and a mutant expressing no β-Mans unexpectedly disseminated more in BALB/c mice, whereas they had neither attenuated nor enhanced virulence in C57BL/6 mice. In galectin (Gal)3 knockout mice, the reference strain was more virulent than in C57BL/6 mice, suggesting that the β-Mans innate receptor Gal3 is involved in C. albicans fitness during infection.
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Affiliation(s)
- Flavie Courjol
- Université de Lille ; Institut National de la Santé et de la Recherche Médicale, Lille Inflammation Research International Center-Unité Mixte de Recherche 995 , France
| | - Thierry Jouault
- Université de Lille ; Institut National de la Santé et de la Recherche Médicale, Lille Inflammation Research International Center-Unité Mixte de Recherche 995 , France
| | - Céline Mille
- Université de Lille ; Institut National de la Santé et de la Recherche Médicale, Lille Inflammation Research International Center-Unité Mixte de Recherche 995 , France
| | - Rebecca Hall
- Aberdeen Fungal Group, School of Medical Sciences , Institute of Medical Sciences , University of Aberdeen , Foresterhill , United Kingdom
| | - Emmanuel Maes
- Université de Lille , Unité de Glycobiologie Structurale et Fonctionnelle ; Centre National de la Recherche Scientifique , Unité Mixte de Recherche 8576 , Villeneuve d'Ascq
| | - Boualem Sendid
- Université de Lille ; Institut National de la Santé et de la Recherche Médicale, Lille Inflammation Research International Center-Unité Mixte de Recherche 995 , France ; Centre Hospitalier Régional Universitaire de Lille, Centre Biologie et Pathologie
| | - Jean Maurice Mallet
- Laboratoire des Biomolécules Unité Mixte de Recherche 7203 , Université Pierre et Marie Curie, Ecole Normale Supérieure , Paris , France
| | - Yann Guerardel
- Université de Lille , Unité de Glycobiologie Structurale et Fonctionnelle ; Centre National de la Recherche Scientifique , Unité Mixte de Recherche 8576 , Villeneuve d'Ascq
| | - Neil A R Gow
- Aberdeen Fungal Group, School of Medical Sciences , Institute of Medical Sciences , University of Aberdeen , Foresterhill , United Kingdom
| | - Daniel Poulain
- Université de Lille ; Institut National de la Santé et de la Recherche Médicale, Lille Inflammation Research International Center-Unité Mixte de Recherche 995 , France ; Centre Hospitalier Régional Universitaire de Lille, Centre Biologie et Pathologie
| | - Chantal Fradin
- Université de Lille ; Institut National de la Santé et de la Recherche Médicale, Lille Inflammation Research International Center-Unité Mixte de Recherche 995 , France
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Corouge M, Loridant S, Fradin C, Salleron J, Damiens S, Moragues MD, Souplet V, Jouault T, Robert R, Dubucquoi S, Sendid B, Colombel JF, Poulain D. Humoral immunity links Candida albicans infection and celiac disease. PLoS One 2015; 10:e0121776. [PMID: 25793717 PMCID: PMC4368562 DOI: 10.1371/journal.pone.0121776] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2014] [Accepted: 02/13/2015] [Indexed: 01/31/2023] Open
Abstract
Objective The protein Hwp1, expressed on the pathogenic phase of Candida albicans, presents sequence analogy with the gluten protein gliadin and is also a substrate for transglutaminase. This had led to the suggestion that C. albicans infection (CI) may be a triggering factor for Celiac disease (CeD) onset. We investigated cross-immune reactivity between CeD and CI. Methods Serum IgG levels against recombinant Hwp1 and serological markers of CeD were measured in 87 CeD patients, 41 CI patients, and 98 healthy controls (HC). IgA and IgG were also measured in 20 individuals from each of these groups using microchips sensitized with 38 peptides designed from the N-terminal of Hwp1. Results CI and CeD patients had higher levels of anti-Hwp1 (p=0.0005 and p=0.004) and anti-gliadin (p=0.002 and p=0.0009) antibodies than HC but there was no significant difference between CeD and CI patients. CeD and CI patients had higher levels of anti-transglutaminase IgA than HC (p=0.0001 and p=0.0039). During CI, the increase in anti-Hwp1 paralleled the increase in anti-gliadin antibodies. Microchip analysis showed that CeD patients were more reactive against some Hwp1 peptides than CI patients, and that some deamidated peptides were more reactive than their native analogs. Binding of IgG from CeD patients to Hwp1 peptides was inhibited by γIII gliadin peptides. Conclusions Humoral cross-reactivity between Hwp1 and gliadin was observed during CeD and CI. Increased reactivity to Hwp1 deamidated peptide suggests that transglutaminase is involved in this interplay. These results support the hypothesis that CI may trigger CeD onset in genetically-susceptible individuals.
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Affiliation(s)
- Marion Corouge
- Université Lille Nord de France, Lille, France
- UDSL, Lille, France
- Service des Maladies de l’Appareil Digestif et de la Nutrition, Lille, France
| | | | - Chantal Fradin
- Université Lille Nord de France, Lille, France
- UDSL, Lille, France
- INSERM U995, Lille, France
| | - Julia Salleron
- Université Lille Nord de France, Lille, France
- UDSL, Lille, France
- EA2694, Lille, France
- Pôle de Santé Publique Registre INSERM/InVS EPIMAD, Lille, France
| | | | - Maria Dolores Moragues
- Departamento de Enfermeria 1, Escuela Universitaria de Enfermeria, Universidad del Pais Vasco, 48940 Leioa, Spain
| | - Vianney Souplet
- Innobiochips, 1 rue du Professeur Calmette, 59000 Lille, France
| | - Thierry Jouault
- Université Lille Nord de France, Lille, France
- UDSL, Lille, France
- INSERM U995, Lille, France
- CHRU, Lille, France
| | - Raymond Robert
- Groupe d’Etude des Interactions Hôte-Pathogène, UPRES-EA 3142, Université d’Angers, Angers, France
| | - Sylvain Dubucquoi
- CHRU, Lille, France
- Institut d’Immunologie, Pôle de Biologie, Lille, France
| | - Boualem Sendid
- Université Lille Nord de France, Lille, France
- UDSL, Lille, France
- INSERM U995, Lille, France
- Service de Parasitologie Mycologie, Institut de Microbiologie, Lille, France
- CHRU, Lille, France
| | - Jean Fréderic Colombel
- Service des Maladies de l’Appareil Digestif et de la Nutrition, Lille, France
- Icahn School of Medicine at Mount Sinai, New York, NY, United States of America
| | - Daniel Poulain
- Université Lille Nord de France, Lille, France
- UDSL, Lille, France
- INSERM U995, Lille, France
- Service de Parasitologie Mycologie, Institut de Microbiologie, Lille, France
- CHRU, Lille, France
- * E-mail:
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Staab JF, Datta K, Rhee P. Niche-specific requirement for hyphal wall protein 1 in virulence of Candida albicans. PLoS One 2013; 8:e80842. [PMID: 24260489 PMCID: PMC3832661 DOI: 10.1371/journal.pone.0080842] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2013] [Accepted: 10/10/2013] [Indexed: 01/19/2023] Open
Abstract
Specialized Candida albicans cell surface proteins called adhesins mediate binding of the fungus to host cells. The mammalian transglutaminase (TG) substrate and adhesin, Hyphal wall protein 1 (Hwp1), is expressed on the hyphal form of C. albicans where it mediates fungal adhesion to epithelial cells. Hwp1 is also required for biofilm formation and mating thus the protein functions in both fungal-host and self-interactions. Hwp1 is required for full virulence of C. albicans in murine models of disseminated candidiasis and of esophageal candidiasis. Previous studies correlated TG activity on the surface of oral epithelial cells, produced by epithelial TG (TG1), with tight binding of C. albicans via Hwp1 to the host cell surfaces. However, the contribution of other Tgs, specifically tissue TG (TG2), to disseminated candidiasis mediated by Hwp1 was not known. A newly created hwp1 null strain in the wild type SC5314 background was as virulent as the parental strain in C57BL/6 mice, and virulence was retained in C57BL/6 mice deleted for Tgm2 (TG2). Further, the hwp1 null strains displayed modestly reduced virulence in BALB/c mice as did strain DD27-U1, an independently created hwp1Δ/Δ in CAI4 corrected for its ura3Δ defect at the URA3 locus. Hwp1 was still needed to produce wild type biofilms, and persist on murine tongues in an oral model of oropharyngeal candidiasis consistent with previous studies by us and others. Finally, lack of Hwp1 affected the translocation of C. albicans from the mouse intestine into the bloodstream of mice. Together, Hwp1 appears to have a minor role in disseminated candidiasis, independent of tissue TG, but a key function in host- and self-association to the surface of oral mucosa.
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Affiliation(s)
- Janet F. Staab
- Johns Hopkins School of Medicine, Johns Hopkins University, Baltimore, Maryland, United States of America
| | - Kausik Datta
- Johns Hopkins School of Medicine, Johns Hopkins University, Baltimore, Maryland, United States of America
| | - Peter Rhee
- Johns Hopkins School of Medicine, Johns Hopkins University, Baltimore, Maryland, United States of America
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Role for the fibrinogen-binding proteins coagulase and Efb in the Staphylococcus aureus-Candida interaction. Int J Med Microbiol 2013; 303:230-8. [PMID: 23684234 DOI: 10.1016/j.ijmm.2013.02.011] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2012] [Revised: 01/31/2013] [Accepted: 02/03/2013] [Indexed: 01/24/2023] Open
Abstract
Staphylococcus aureus and Candida species are increasingly coisolated from implant-associated polymicrobial infections creating an incremental health care problem. Synergistic effects between both genera seem to facilitate the formation of mixed S. aureus-Candida biofilms, which is thought to play a critical role in coinfections with these microorganisms. To identify and characterize S. aureus factors involved in the interaction with Candida species, we affinity-panned an S. aureus phage display library against Candida biofilms in the presence or absence of fibrinogen. Repeatedly isolated clones contained DNA fragments encoding portions of the S. aureus fibrinogen-binding proteins coagulase or Efb. The coagulase binds to prothrombin in a 1:1 ratio thereby inducing a conformational change and non-proteolytic activation of prothrombin, which in turn cleaves fibrinogen to fibrin. Efb has been known to inhibit opsonization. To study the role of coagulase and Efb in the S. aureus-Candida cross-kingdom interaction, we performed flow-cytometric phagocytosis assays. Preincubation with coagulase reduced the phagocytosis of Candida yeasts by granulocytes significantly and dose-dependently. By using confocal laser scanning microscopy, we demonstrated that the coagulase mediated the formation of fibrin surrounding the candidal cells. Furthermore, the addition of Efb significantly protected the yeasts against phagocytosis by granulocytes in a dose-dependent and saturable fashion. In conclusion, the inhibition of phagocytosis of Candida cells by coagulase and Efb via two distinct mechanisms suggests that S. aureus might be beneficial for Candida to persist as it helps Candida to circumvent the host immune system.
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Abstract
Understanding the pathogenesis of an infectious disease is critical for developing new methods to prevent infection and diagnose or cure disease. Adherence of microorganisms to host tissue is a prerequisite for tissue invasion and infection. Fungal cell wall adhesins involved in adherence to host tissue or abiotic medical devices are critical for colonization leading to invasion and damage of host tissue. Here, with a main focus on pathogenic Candida species, we summarize recent progress made in the field of adhesins in human fungal pathogens and underscore the importance of these proteins in establishment of fungal diseases.
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32
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Zhang Y, Cai C, Yang Y, Weng L, Wang L. Blocking of Candida albicans biofilm formation by cis-2-dodecenoic acid and trans-2-dodecenoic acid. J Med Microbiol 2011; 60:1643-1650. [DOI: 10.1099/jmm.0.029058-0] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023] Open
Affiliation(s)
- YuQian Zhang
- Department of Microbiology and Microbial Engineering, School of Life Sciences, Fudan University, Shanghai 200433, PR China
| | - Chen Cai
- Department of Microbiology and Microbial Engineering, School of Life Sciences, Fudan University, Shanghai 200433, PR China
| | - YuXiang Yang
- Department of Microbiology and Microbial Engineering, School of Life Sciences, Fudan University, Shanghai 200433, PR China
| | - Lixing Weng
- Department of Microbiology and Microbial Engineering, School of Life Sciences, Fudan University, Shanghai 200433, PR China
| | - LianHui Wang
- Institute of Advanced Materials, Nanjing University of Posts and Telecommunications, Nanjing, Jiangsu, 210046, PR China
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Martin R, Wächtler B, Schaller M, Wilson D, Hube B. Host-pathogen interactions and virulence-associated genes during Candida albicans oral infections. Int J Med Microbiol 2011; 301:417-22. [PMID: 21555244 DOI: 10.1016/j.ijmm.2011.04.009] [Citation(s) in RCA: 50] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023] Open
Abstract
Oral infections with Candida albicans are very common diseases in even only mildly immunocompromised patients. By using genome-wide microarrays, in vitro infection models and samples from patients with pseudomembranous candidiasis, several genes have been identified which encode known and unknown fungal factors associated with oral infection. The expression of selected genes has been investigated via qRT-PCR in both in vitro models and in vivo samples from patients. Several lines of evidence suggest that fungal morphology plays a key role in adhesion to and invasion into oral epithelial cells and mutants lacking regulators of hyphal formation are attenuated in their ability to invade and damage epithelial cells. Adhesion is mediated by hyphal-associated factors such as Hwp1 and the Als adhesin family. Hyphal formation facilitates epithelial invasion via two routes: active penetration and induced endocytosis. While induced endocytosis is predominantly mediated by the adhesin and invasin Als3, active penetration seems to be supported by hydrolase activity and mechanical pressure. Expression profiles reflect the morphological switch and an adaptive response to neutral pH, non-glucose carbon sources, and nitrosative stress.
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Affiliation(s)
- Ronny Martin
- Center for Innovation Competence Septomics, Research Group Fungal Septomics at the Leibniz Institute for Natural Products Research and Infection Biology-Hans Knoell Institute (HKI), Jena, Germany
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Vílchez R, Lemme A, Ballhausen B, Thiel V, Schulz S, Jansen R, Sztajer H, Wagner-Döbler I. Streptococcus mutans inhibits Candida albicans hyphal formation by the fatty acid signaling molecule trans-2-decenoic acid (SDSF). Chembiochem 2010; 11:1552-62. [PMID: 20572249 DOI: 10.1002/cbic.201000086] [Citation(s) in RCA: 99] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023]
Abstract
In the human mouth, fungi and several hundred species of bacteria coexist. Here we report a case of interkingdom signaling in the oral cavity: A compound excreted by the caries bacterium Streptococcus mutans inhibits the morphological transition from yeast to hyphae, an important virulence trait, in the opportunistic fungus Candida albicans. The compound excreted by S. mutans was originally studied because it inhibited signaling by the universal bacterial signal autoinducer-2 (AI-2), determined by the luminescence of a Vibrio harveyi sensor strain. The inhibitor was purified from cell-free culture supernatants of S. mutans guided by its activity. Its chemical structure was elucidated by using NMR spectroscopy and GC-MS and proved to be trans-2-decenoic acid. We show that trans-2-decenoic acid does not inhibit AI-2-specific signaling, but rather the luciferase reaction used for its detection. A potential biological role of trans-2-decenoic acid was then discovered. It is able to suppress the transition from yeast to hyphal morphology in the opportunistic human pathogen Candida albicans at concentrations that do not affect growth. The expression of HWP1, a hyphal-specific signature gene of C. albicans, is abolished by trans-2-decenoic acid. trans-2-Decenoic acid is structurally similar to the diffusible signal factor (DSF) family of interkingdom-signaling molecules and is the first member of this family from a Gram-positive organism (Streptococcus DSF, SDSF). SDSF activity was also found in S. mitis, S. oralis, and S. sanguinis, but not in other oral bacteria. SDSF could be relevant in shaping multispecies Candida bacteria biofilms in the human body.
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Affiliation(s)
- Ramiro Vílchez
- Helmholtz-Center for Infection Research (HZI), Inhoffenstrasse 7, 38124 Braunschweig, Germany
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Padovan ACB, Chaves GM, Colombo AL, Briones MRS. A novel allele of HWP1, isolated from a clinical strain of Candida albicans with defective hyphal growth and biofilm formation, has deletions of Gln/Pro and Ser/Thr repeats involved in cellular adhesion. Med Mycol 2010; 47:824-35. [PMID: 19184714 DOI: 10.3109/13693780802669574] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Gene HWP1 encodes a major Candida albicans hyphae cell wall protein which is a substrate of mammalian transglutaminases, promoting the cross-link of the fungus to epithelial cells. Here, we describe a novel HWP1 allele, isolated from C. albicans blood isolates. Analysis of the translated sequence shows that three important regions are absent in the novel allele, HWP1-2, relative to the previously described allele, HWP1-1. Regions 1 and 2 consist of 10 amino acid repeats important for functional conformation of peptide chains and attachment of C. albicans cells to the mammalian epithelia. Region 3 consists of 34 amino acid residues rich in threonine and serine, with O-glycosylation sites that promote the cross-linking with other proteins on C. albicans surface. The HWP1-2 homozygous strain L757 and the heterozygous strain L296 (HWP1-1/HWP1-2) have significantly lower levels of HWP1 expression during hyphal growth and biofilm formation compared to strain SC5314 (HWP1-1/HWP1-1). However, strain L296 properly forms hyphae and biofilms in vitro while strain L757 has reduced hyphal growth (40.4%) and biofilm formation (90.8%). Our results indicate that the HWP1 locus has biofilm specific allelic differential expression and suggest that the HWP1-2 encoded protein is less efficient to maintain cell-to-cell and cell-to-surface adhesion during biofilm formation. This is the first report of a natural variant of HWP1.
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Affiliation(s)
- Ana Carolina B Padovan
- Departamento de Microbiologia, Imunologia e Parasitologia, Universidade Federal de São Paulo, São Paulo, SP, Brazil
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36
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Zhang N, Cannon RD, Holland BR, Patchett ML, Schmid J. Impact of genetic background on allele selection in a highly mutable Candida albicans gene, PNG2. PLoS One 2010; 5:e9614. [PMID: 20231904 PMCID: PMC2834760 DOI: 10.1371/journal.pone.0009614] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2009] [Accepted: 02/16/2010] [Indexed: 11/19/2022] Open
Abstract
In many microbes rapid mutation of highly mutable contingency genes continually replenishes a pool of variant alleles from which the most suitable are selected, assisting in rapid adaptation and evasion of the immune response. In some contingency genes mutability is achieved through DNA repeats within the coding region. The fungal human pathogen Candida albicans has 2600 repeat-containing ORFs. For those investigated (ALS genes, HYR1, HYR2, CEK1, RLM1) many protein variants with differing amino acid repeat regions exist, as expected for contingency genes. However, specific alleles dominate in different clades, which is unexpected if allele variation is used for short-term adaptation. Generation of new alleles of repeat-containing C. albicans ORFs has never been observed directly. Here we present evidence for restrictions on the emergence of new alleles in a highly mutable C. albicans repeat-containing ORF, PNG2, encoding a putative secreted or cell surface glycoamidase. In laboratory cultures new PNG2 alleles arose at a rate of 2.8×10−5 (confidence interval 3.3×10−6−9. 9×10−5) per cell per division, comparable to rates measured for contingency genes. Among 80 clinical isolates 17 alleles of different length and 23 allele combinations were distinguishable; sequence differences between repeat regions of identical size suggest the existence of 36 protein variants. Specific allele combinations predominated in different genetic backgrounds, as defined by DNA fingerprinting and multilocus sequence typing. Given the PNG2 mutation rate, this is unexpected, unless in different genetic backgrounds selection favors different alleles. Specific alleles or allele combinations were not preferentially associated with C. albicans isolates from particular body sites or geographical regions. Our results suggest that the mutability of PNG2 is not used for short-term adaptation or evasion of the immune system. Nevertheless the large number of alleles observed indicates that mutability of PNG2 may assist C. albicans strains from different genetic backgrounds optimize their interaction with the host in the long term.
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Affiliation(s)
- Ningxin Zhang
- Institute of Molecular BioSciences, Massey University, Palmerston North, New Zealand
| | - Richard D. Cannon
- Department of Oral Sciences, University of Otago, Dunedin, New Zealand
| | - Barbara R. Holland
- Allan Wilson Centre for Molecular Ecology and Evolution, Massey University, Palmerston North, New Zealand
| | - Mark L. Patchett
- Institute of Molecular BioSciences, Massey University, Palmerston North, New Zealand
| | - Jan Schmid
- Institute of Molecular BioSciences, Massey University, Palmerston North, New Zealand
- * E-mail:
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Romeo O, De Leo F, Criseo G. Adherence ability of Candida africana: a comparative study with Candida albicans and Candida dubliniensis. Mycoses 2010; 54:e57-61. [DOI: 10.1111/j.1439-0507.2009.01833.x] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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38
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Mora-Montes HM, Ponce-Noyola P, Villagómez-Castro JC, Gow NA, Flores-Carreón A, López-Romero E. Protein glycosylation in Candida. Future Microbiol 2010; 4:1167-83. [PMID: 19895219 DOI: 10.2217/fmb.09.88] [Citation(s) in RCA: 66] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023] Open
Abstract
Candidiasis is a significant cause of invasive human mycosis with associated mortality rates that are equivalent to, or worse than, those cited for most cases of bacterial septicemia. As a result, considerable efforts are being made to understand how the fungus invades host cells and to identify new targets for fungal chemotherapy. This has led to an increasing interest in Candida glycobiology, with an emphasis on the identification of enzymes essential for glycoprotein and adhesion metabolism, and the role of N- and O-linked glycans in host recognition and virulence. Here, we refer to studies dealing with the identification and characterization of enzymes such as dolichol phosphate mannose synthase, dolichol phosphate glucose synthase and processing glycosidases and synthesis, structure and recognition of mannans and discuss recent findings in the context of Candida albicans pathogenesis.
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Abstract
The fungus, Candida albicans, interacts with epithelial cells in the human host both as a normal commensal and as an invasive pathogen. It has evolved multiple complementary mechanisms to adhere to epithelial cells. Adherent C. albicans cells can invade epithelial surfaces both by penetrating into individual epithelial cells, and by degrading interepithelial cell junctions and passing between epithelial cells. Invasion into epithelial cells is mediated by both induced endocytosis and active penetration, whereas degradation of epithelial cell junction proteins, such as E-cadherin, occurs mainly via proteolysis by secreted aspartyl proteinases. C. albicans invasion of epithelial cells results in significant epithelial cell damage, which is probably induced by lytic enzymes, such as proteases and phospholipase secreted by the organism. Future challenges include identifying the epithelial cell targets of adhesins and invasins, and determining the mechanisms by which C. albicans actively penetrates epithelial cells and induces epithelial cell damage.
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Affiliation(s)
- Weidong Zhu
- Divison of Infectious Disease, Department of Medicine, Los Angeles Biomedical Research Institute at Harbor-UCLA Medical Center, Torrance, CA 90502, USA
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40
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Klis FM, Sosinska GJ, de Groot PWJ, Brul S. Covalently linked cell wall proteins of Candida albicans and their role in fitness and virulence. FEMS Yeast Res 2009; 9:1013-28. [PMID: 19624749 DOI: 10.1111/j.1567-1364.2009.00541.x] [Citation(s) in RCA: 120] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023] Open
Abstract
The cell wall of Candida albicans consists of an internal skeletal layer and an external protein coat. This coat has a mosaic-like nature, containing c. 20 different protein species covalently linked to the skeletal layer. Most of them are GPI proteins. Coat proteins vary widely in function. Many of them are involved in the primary interactions between C. albicans and the host and mediate adhesive steps or invasion of host cells. Others are involved in biofilm formation and cell-cell aggregation. They further include iron acquisition proteins, superoxide dismutases, and yapsin-like aspartic proteases. In addition, several covalently linked carbohydrate-active enzymes are present, whose precise functions remain hitherto largely elusive. The expression levels of the genes that encode covalently linked cell wall proteins (CWPs) can vary enormously. They depend on the mode of growth and the combined inputs of several signaling pathways that sense environmental conditions. This is reflected in the unusually long intergenic regions of most of these genes. Finally, the precise location of several covalently linked CWPs is temporally and spatially regulated. We conclude that covalently linked CWPs of C. albicans play a crucial role in fitness and virulence and that their expression is tightly controlled.
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Affiliation(s)
- Frans M Klis
- Swammerdam Institute for Life Sciences, University of Amsterdam, 1018 WV Amsterdam, The Netherlands.
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ten Cate J, Klis F, Pereira-Cenci T, Crielaard W, de Groot P. Molecular and Cellular Mechanisms That Lead to Candida Biofilm Formation. J Dent Res 2009; 88:105-15. [DOI: 10.1177/0022034508329273] [Citation(s) in RCA: 100] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023] Open
Abstract
Fungal infections in the oral cavity are mainly caused by C. albicans, but other Candida species are also frequently identified. They are increasing in prevalence, especially in denture-wearers and aging people, and may lead to invasive infections, which have a high mortality rate. Attachment to mucosal tissues and to abiotic surfaces and the formation of biofilms are crucial steps for Candida survival and proliferation in the oral cavity. Candida species possess a wide arsenal of glycoproteins located at the exterior side of the cell wall, many of which play a determining role in these steps. In addition, C. albicans secretes signaling molecules that inhibit the yeast-to-hypha transition and biofilm formation. In vivo, Candida species are members of mixed biofilms, and subject to various antagonistic and synergistic interactions, which are beginning to be explored. We believe that these new insights will allow for more efficacious treatments of fungal oral infections. For example, the use of signaling molecules that inhibit biofilm formation should be considered. In addition, cell-wall biosynthetic enzymes, wall cross-linking enzymes, and wall proteins, which include adhesins, proteins involved in biofilm formation, fungal-bacterial interactions, and competition for surface colonization sites, offer a wide range of potential targets for therapeutic intervention.
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Affiliation(s)
- J.M. ten Cate
- Department of Cariology Endodontology Pedodontology, Academic Centre for Dentistry Amsterdam -ACTA-, University of Amsterdam and Free University Amsterdam, Louwesweg 1, 1066 EA Amsterdam, the Netherlands
- Swammerdam Institute for Life Sciences, University of Amsterdam, Amsterdam, the Netherlands; and
- Department of Prosthodontics and Periodontology, Faculty of Dentistry of Piracicaba, UNICAMP, Brazil
| | - F.M. Klis
- Department of Cariology Endodontology Pedodontology, Academic Centre for Dentistry Amsterdam -ACTA-, University of Amsterdam and Free University Amsterdam, Louwesweg 1, 1066 EA Amsterdam, the Netherlands
- Swammerdam Institute for Life Sciences, University of Amsterdam, Amsterdam, the Netherlands; and
- Department of Prosthodontics and Periodontology, Faculty of Dentistry of Piracicaba, UNICAMP, Brazil
| | - T. Pereira-Cenci
- Department of Cariology Endodontology Pedodontology, Academic Centre for Dentistry Amsterdam -ACTA-, University of Amsterdam and Free University Amsterdam, Louwesweg 1, 1066 EA Amsterdam, the Netherlands
- Swammerdam Institute for Life Sciences, University of Amsterdam, Amsterdam, the Netherlands; and
- Department of Prosthodontics and Periodontology, Faculty of Dentistry of Piracicaba, UNICAMP, Brazil
| | - W. Crielaard
- Department of Cariology Endodontology Pedodontology, Academic Centre for Dentistry Amsterdam -ACTA-, University of Amsterdam and Free University Amsterdam, Louwesweg 1, 1066 EA Amsterdam, the Netherlands
- Swammerdam Institute for Life Sciences, University of Amsterdam, Amsterdam, the Netherlands; and
- Department of Prosthodontics and Periodontology, Faculty of Dentistry of Piracicaba, UNICAMP, Brazil
| | - P.W.J. de Groot
- Department of Cariology Endodontology Pedodontology, Academic Centre for Dentistry Amsterdam -ACTA-, University of Amsterdam and Free University Amsterdam, Louwesweg 1, 1066 EA Amsterdam, the Netherlands
- Swammerdam Institute for Life Sciences, University of Amsterdam, Amsterdam, the Netherlands; and
- Department of Prosthodontics and Periodontology, Faculty of Dentistry of Piracicaba, UNICAMP, Brazil
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42
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Coleman DA, Hoyer LL. Interactions between pathogenic fungi and human epithelial and endothelial surfaces. CURRENT FUNGAL INFECTION REPORTS 2008. [DOI: 10.1007/s12281-008-0024-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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C-terminal signals regulate targeting of glycosylphosphatidylinositol-anchored proteins to the cell wall or plasma membrane in Candida albicans. EUKARYOTIC CELL 2008; 7:1906-15. [PMID: 18723603 DOI: 10.1128/ec.00148-08] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Fungal glycosylphosphatidylinositol (GPI)-anchored proteins localize to the plasma membrane (PM), cell wall (CW), or both. To study signals that regulate PM versus CW targeting in Candida albicans, we (i) fused the N and/or C termini of the GPI CW protein Hwp1p and the GPI PM protein Ecm331p to green fluorescent protein (GFP) and (ii) expressed and localized the resulting fusions. Forty-seven amino acids from the C terminus of Hwp1p were sufficient to target GFP to the CW, and 66 amino acids from the C terminus of Ecm331p were sufficient to target GFP to the PM. Truncation and mutagenesis studies showed that G390 was the omega cleavage site in Ecm331p. Domain exchange and mutagenesis studies showed that (i) the 5 amino acids immediately N-terminal to the omega sites (the omega - 5 to omega - 1 amino acids) played key roles in targeting to the PM or CW; (ii) KK and FE residues at positions omega - 1 and omega - 2, respectively, targeted to the PM and CW; and (iii) a loss of I at position omega - 5 increased PM retention. Small fluorescent reporters can be used to study the peptide signals that regulate PM versus CW targeting of GPI proteins and may be useful for identifying proteins that interact with key targeting signals.
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Levdansky E, Sharon H, Osherov N. Coding fungal tandem repeats as generators of fungal diversity. FUNGAL BIOL REV 2008. [DOI: 10.1016/j.fbr.2008.08.001] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
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Beta-1,2 oligomannose adhesin epitopes are widely distributed over the different families of Candida albicans cell wall mannoproteins and are associated through both N- and O-glycosylation processes. Infect Immun 2008; 76:4509-17. [PMID: 18644880 DOI: 10.1128/iai.00368-08] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023] Open
Abstract
Beta-1,2-linked mannosides (beta-Mans) are believed to contribute to Candida albicans virulence. The presence of beta-Mans has been chemically established for two molecules (phosphopeptidomannan [PPM] and phospholipomannan) that are noncovalently linked to the cell wall, where they correspond to specific epitopes. However, a large number of cell wall mannoproteins (CWMPs) also express beta-Man epitopes, although their nature and mode of beta-mannosylation are unknown. We therefore used Western blotting to map beta-Man epitopes for the different families of mannoproteins gradually released from the cell wall according to their mode of anchorage (soluble, released by dithiothreitol, beta-1,3 glucan linked, and beta-1,6 glucan linked). Reduction of beta-Man epitope expression occurred after chemical and enzymatic deglycosylation of the different cell wall fractions, as well as in a secreted form of Hwp1, a representative of the CWMPs linked by glycosylphosphatidylinositol remnants. Enzyme-linked immunosorbent assay inhibition tests were performed to assess the presence of beta-Man epitopes in released oligomannosides. A comparison of the results obtained with CWMPs to the results obtained with PPM and the use of mutants with mutations affecting O and N glycosylation demonstrated that both O glycosylation and N glycosylation participate in the association of beta-Mans with the protein moieties of CWMPs. This process, which can alter the function of cell wall molecules and their recognition by the host, is therefore more important and more complex than originally thought, since it differs from the model established previously with PPM.
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Use of recombinant antigens for the diagnosis of invasive candidiasis. Clin Dev Immunol 2008; 2008:721950. [PMID: 18382617 PMCID: PMC2276615 DOI: 10.1155/2008/721950] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2007] [Accepted: 01/31/2008] [Indexed: 01/12/2023]
Abstract
Invasive candidiasis is a frequent and often fatal complication in immunocompromised and critically ill patients. Unfortunately, the diagnosis of invasive candidiasis remains difficult due to the lack of specific clinical symptoms and a definitive diagnostic method. The detection of antibodies against different Candida antigens may help in the diagnosis. However, the methods traditionally used for the detection of antibodies have been based on crude antigenic fungal extracts, which usually show low-reproducibility and cross-reactivity problems. The development of molecular biology techniques has allowed the production of recombinant antigens which may help to solve these problems. In this review we will discuss the usefulness of recombinant antigens in the diagnosis of invasive candidiasis.
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Yin QY, de Groot PW, de Koster CG, Klis FM. Mass spectrometry-based proteomics of fungal wall glycoproteins. Trends Microbiol 2008; 16:20-6. [DOI: 10.1016/j.tim.2007.10.011] [Citation(s) in RCA: 52] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2007] [Revised: 10/30/2007] [Accepted: 10/30/2007] [Indexed: 11/26/2022]
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Ponniah G, Rollenhagen C, Bahn YS, Staab JF, Sundstrom P. State of differentiation defines buccal epithelial cell affinity for cross-linking to Candida albicans Hwp1. J Oral Pathol Med 2007; 36:456-67. [PMID: 17686003 DOI: 10.1111/j.1600-0714.2007.00565.x] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
Candida albicans utilizes mammalian cell-associated transglutaminase (TGase) activity to adhere covalently to human buccal epithelial cells (BECs) through Hyphal Wall Protein 1. Little is known about the factors leading to the identity and appearance of Hwp1 binding partners on cells lining the oral cavity. The observation that BECs vary in their ability to attach to C. albicans germ tubes and to bind recombinant Hwp1 (rHwp1) suggested that differentiation may play a role in affinity for germ tube attachment. Individual BECs were characterized for differentiation status and rHwp1 binding. rHwp1 bound to the more terminally differentiated cells displaying SPR3 and keratin 13 but not to less differentiated cells with abundant involucrin. Sequential expression of involucrin followed by SPR3 in oral keratinocytes was demonstrated using stratified organotypic cultures and a feeder layer system with the OKF6/TERT-2 cell line. Increased cross-linking of the lysine analogue 5-(biotinamido)pentylamine to cultured OKF6/TERT-2 cell proteins accompanied this increased expression of SPR3. Western blot analysis demonstrated the presence of rHwp1 cross-links to proteins from BECs or from OKF6/TERT-2 cells that had been mechanically dislodged from culture dishes. Therefore, the differentiation of SPR3 positive from involucrin positive cells is correlated with the acquisition of affinity for cross-linking to rHwp1 and covalent adhesion of germ tubes to BECs.
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Affiliation(s)
- Gomathinayagam Ponniah
- Department of Microbiology and Immunology, Dartmouth Medical School, Hanover, NH 03755, USA
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Genome-wide transcriptional profiling of the cyclic AMP-dependent signaling pathway during morphogenic transitions of Candida albicans. EUKARYOTIC CELL 2007; 6:2376-90. [PMID: 17951520 DOI: 10.1128/ec.00318-07] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Candida albicans is an opportunistic human fungal pathogen that causes systemic candidiasis as well as superficial mucosal candidiasis. In response to the host environment, C. albicans transitions between yeast and hyphal forms. In particular, hyphal growth is important in facilitating adhesion and invasion of host tissues, concomitant with the expression of various hypha-specific virulence factors. In previous work, we showed that the cyclic AMP (cAMP) signaling pathway plays a crucial role in morphogenic transitions and virulence of C. albicans by studying genes encoding adenylate cyclase-associated protein (CAP1) and high-affinity phosphodiesterase (PDE2) (Y. S. Bahn, J. Staab, and P. Sundstrom, Mol. Microbiol. 50:391-409, 2003; and Y. S. Bahn and P. Sundstrom, J. Bacteriol. 183:3211-3223, 2001). However, little is known about the downstream targets of the cAMP signaling pathway that are responsible for morphological transitions and the expression of virulence factors. Here, microarrays were probed with RNA from strains with hypoactive (cap1/cap1 null mutant), hyperactive (pde2/pde2 null mutant), and wild-type cAMP signaling pathways to provide insight into the molecular mechanisms of virulence that are regulated by cAMP and that are related to the morphogenesis of C. albicans. Genes controlling metabolic specialization, cell wall structure, ergosterol/lipid biosynthesis, and stress responses were modulated by cAMP during hypha formation. Phenotypic traits predicted to be regulated by cAMP from the profiling results correlated with the relative strengths of the mutants when tested for resistance to azoles and subjected to heat shock stress and oxidative/nitrosative stress. The results from this study provide important insights into the role of the cAMP signaling pathway not only in morphogenic transitions of C. albicans but also for adaptation to stress and for survival during host infections.
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Dranginis AM, Rauceo JM, Coronado JE, Lipke PN. A biochemical guide to yeast adhesins: glycoproteins for social and antisocial occasions. Microbiol Mol Biol Rev 2007; 71:282-94. [PMID: 17554046 PMCID: PMC1899881 DOI: 10.1128/mmbr.00037-06] [Citation(s) in RCA: 219] [Impact Index Per Article: 12.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Fungi are nonmotile eukaryotes that rely on their adhesins for selective interaction with the environment and with other fungal cells. Glycosylphosphatidylinositol (GPI)-cross-linked adhesins have essential roles in mating, colony morphology, host-pathogen interactions, and biofilm formation. We review the structure and binding properties of cell wall-bound adhesins of ascomycetous yeasts and relate them to their effects on cellular interactions, with particular emphasis on the agglutinins and flocculins of Saccharomyces and the Als proteins of Candida. These glycoproteins share common structural motifs tailored to surface activity and biological function. After being secreted to the outer face of the plasma membrane, they are covalently anchored in the wall through modified GPI anchors, with their binding domains elevated beyond the wall surface on highly glycosylated extended stalks. N-terminal globular domains bind peptide or sugar ligands, with between millimolar and nanomolar affinities. These affinities and the high density of adhesins and ligands at the cell surface determine microscopic and macroscopic characteristics of cell-cell associations. Central domains often include Thr-rich tandemly repeated sequences that are highly glycosylated. These domains potentiate cell-to-cell binding, but the molecular mechanism of such an association is not yet clear. These repeats also mediate recombination between repeats and between genes. The high levels of recombination and epigenetic regulation are sources of variation which enable the population to continually exploit new niches and resources.
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Affiliation(s)
- Anne M Dranginis
- Department of Biological Science, St John's University, Queens, New York, USA
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