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A conserved regulator controls asexual sporulation in the fungal pathogen Candida albicans. Nat Commun 2020; 11:6224. [PMID: 33277479 PMCID: PMC7718266 DOI: 10.1038/s41467-020-20010-9] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2020] [Accepted: 11/03/2020] [Indexed: 12/16/2022] Open
Abstract
Transcription factor Rme1 is conserved among ascomycetes and regulates meiosis and pseudohyphal growth in Saccharomyces cerevisiae. The genome of the meiosis-defective pathogen Candida albicans encodes an Rme1 homolog that is part of a transcriptional circuitry controlling hyphal growth. Here, we use chromatin immunoprecipitation and genome-wide expression analyses to study a possible role of Rme1 in C. albicans morphogenesis. We find that Rme1 binds upstream and activates the expression of genes that are upregulated during chlamydosporulation, an asexual process leading to formation of large, spherical, thick-walled cells during nutrient starvation. RME1 deletion abolishes chlamydosporulation in three Candida species, whereas its overexpression bypasses the requirement for chlamydosporulation cues and regulators. RME1 expression levels correlate with chlamydosporulation efficiency across clinical isolates. Interestingly, RME1 displays a biphasic pattern of expression, with a first phase independent of Rme1 function and dependent on chlamydospore-inducing cues, and a second phase dependent on Rme1 function and independent of chlamydospore-inducing cues. Our results indicate that Rme1 plays a central role in chlamydospore development in Candida species.
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Vrablikova A, Czernekova L, Cahlikova R, Novy Z, Petrik M, Imran S, Novak Z, Krupka M, Cerovsky V, Turanek J, Raska M. Lasioglossins LLIII affect the morphogenesis of Candida albicans and reduces the duration of experimental vaginal candidiasis in mice. Microbiol Immunol 2017; 61:474-481. [PMID: 28892177 DOI: 10.1111/1348-0421.12538] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2016] [Revised: 05/22/2017] [Accepted: 09/07/2017] [Indexed: 11/30/2022]
Abstract
Lasioglossins are a group of peptides with identified antimicrobial activity. The inhibitory effects of two synthetic lasioglossin derivatives, LLIII and D-isomeric variant LLIII-D, on morphological changes in Candida albicans in vitro and the effect of local administration of LLIII during experimental murine candidiasis were investigated. C. albicans blastoconidia were grown in the presence of lasioglossin LLIII or LLIII-D at concentrations of 11.5 μM and 21 μM, respectively, for 1, 2 and 3 days and their viability determined by flow cytometry using eosin Y staining. Morphological changes were examined by light and fluorescent microscopy. The Candida-inhibitory effect of daily intravaginal administration of 0.7 or 1.4 μg of LLIII was assessed in mice with experimentally-induced vaginal candidiasis. LLIII and LLIII-D lasioglossins exhibited candidacidal activity in vitro (>76% after 24 hr and >84% after 48 hr of incubation). After 72 hr incubation of Candida with low concentration of lasioglossins, an increase in viability was detected, probably due to a Candida antimicrobial peptides evasion strategy. Furthermore, lasioglossins inhibited temperature-induced morphotype changes toward hyphae and pseudohyphae with sporadic occurrence of atypical cells with two or enlarged nuclei, suggesting interference with mitosis or cytokinesis. Local application of LLIII reduced the duration of experimental candidiasis with no evidence of adverse effects. Lasioglossin LLIII is a promising candidate for development as an antimicrobial drug for treating the vaginal candidiasis.
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Affiliation(s)
- Alena Vrablikova
- Department of Immunology, Faculty of Medicine and Dentistry, Palacky University in Olomouc, Hnevotinska 3, 772 00 Olomouc, Czech Republic
| | - Lydie Czernekova
- Department of Immunology, Faculty of Medicine and Dentistry, Palacky University in Olomouc, Hnevotinska 3, 772 00 Olomouc, Czech Republic
| | - Romana Cahlikova
- Department of Immunology, Faculty of Medicine and Dentistry, Palacky University in Olomouc, Hnevotinska 3, 772 00 Olomouc, Czech Republic
| | - Zbynek Novy
- Institute of Molecular and Translational Medicine, Faculty of Medicine and Dentistry, Palacky University in Olomouc, Hnevotinska 3, 772 00 Olomouc, Czech Republic
| | - Milos Petrik
- Institute of Molecular and Translational Medicine, Faculty of Medicine and Dentistry, Palacky University in Olomouc, Hnevotinska 3, 772 00 Olomouc, Czech Republic
| | - Saima Imran
- Department of Immunology, Faculty of Medicine and Dentistry, Palacky University in Olomouc, Hnevotinska 3, 772 00 Olomouc, Czech Republic
| | - Zdenek Novak
- Department of Surgery, University of Alabama at Birmingham, BDB 503, 18th St. So., 35294, Birmingham, Alabama, USA
| | - Michal Krupka
- Department of Immunology, Faculty of Medicine and Dentistry, Palacky University in Olomouc, Hnevotinska 3, 772 00 Olomouc, Czech Republic
| | - Vaclav Cerovsky
- Institute of Organic Chemistry and Biochemistry, Academy of Sciences of the Czech Republic, Flemingovo náměstí 542/2, 166 10 Praha, Czech Republic
| | - Jaroslav Turanek
- Department of Pharmacology and Immunotherapy, Veterinary Research Institute, Hudcova 296/70, 621 00 Brno, Czech Republic
| | - Milan Raska
- Department of Immunology, Faculty of Medicine and Dentistry, Palacky University in Olomouc, Hnevotinska 3, 772 00 Olomouc, Czech Republic.,Institute of Molecular and Translational Medicine, Faculty of Medicine and Dentistry, Palacky University in Olomouc, Hnevotinska 3, 772 00 Olomouc, Czech Republic.,Department of Pharmacology and Immunotherapy, Veterinary Research Institute, Hudcova 296/70, 621 00 Brno, Czech Republic
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Johnson S, Nguyen V, Coder D. Assessment of cell viability. CURRENT PROTOCOLS IN CYTOMETRY 2013; Chapter 9:9.2.1-9.2.26. [PMID: 23546778 DOI: 10.1002/0471142956.cy0902s64] [Citation(s) in RCA: 45] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
Cell viability may be judged by morphological changes or by changes in membrane permeability and/or physiological state inferred from the exclusion of certain dyes or the uptake and retention of others. This unit presents methods based on dye exclusion, esterase activity, and mitochondrial membrane potential, as well as protocols for determining the pre-fixation viability of fixed cells either before or after fixation with amine-reactive dyes suitable for a range of excitation wavelengths. Membrane-impermeable dead cell and live cell dyes as well as dye-exclusion procedures for microscopy are also included.
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Affiliation(s)
- Simon Johnson
- University of Washington School of Medicine, Seattle, Washington
| | - Vy Nguyen
- University of Washington School of Medicine, Seattle, Washington
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Perfetto SP, Chattopadhyay PK, Lamoreaux L, Nguyen R, Ambrozak D, Koup RA, Roederer M. Amine-reactive dyes for dead cell discrimination in fixed samples. CURRENT PROTOCOLS IN CYTOMETRY 2010; Chapter 9:Unit 9.34. [PMID: 20578108 PMCID: PMC2915540 DOI: 10.1002/0471142956.cy0934s53] [Citation(s) in RCA: 56] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Amine-reactive dyes, also known as LIVE/DEAD fixable dead cell stains, are a class of viability dyes suitable for identifying dead cells in samples that will be fixed. These dyes cross the cell membranes of dead cells, and react with free amines in the cytoplasm. Live cells exclude these dyes because their cell membranes are intact, and free dye is washed away after staining. Notably, the reaction is irreversible; therefore, when cells are fixed and permeabilized (as with intracellular staining procedures), the bound dye remains associated with the dead cells (unlike other viability dyes). Since amine-reactive dyes are fluorescent when excited by lasers, dead cells can be identified by flow cytometry. This unit describes procedures, troubleshooting, and outcomes for using the two most commonly used amine-reactive dyes, ViViD and Aqua Blue.
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Microtubule motor protein Kar3 is required for normal mitotic division and morphogenesis in Candida albicans. EUKARYOTIC CELL 2008; 7:1460-74. [PMID: 18586948 DOI: 10.1128/ec.00138-08] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
The kinesin-related protein Kar3 is a minus end-directed molecular motor that plays a multifunctional role in microtubule-directed nuclear movement. Previously, it was shown that Candida albicans Kar3p is critical for nuclear fusion during mating as kar3 mutants were defective in karyogamy. In this study, we confirm that Kar3p is required for nuclear congression in mating but that neither Kar3p nor the dynein motor protein Dyn1p is required for nuclear migration in the mating projection prior to cell fusion. In addition, we show that C. albicans Kar3p plays an important role in the cell and colony morphology of mitotically dividing cells, as evidenced by diminished filamentation of kar3 cells on Spider medium and an increased tendency of mutant cells to form pseudohyphal cells in liquid culture. Loss of Kar3p also led to defects in nuclear division, causing cells to grow slowly and exhibit reduced viability compared to wild-type cells. Slow growth was due, at least in part, to delayed cell cycle progression, as cells lacking Kar3p accumulated in anaphase of the cell cycle. Consistent with a role in mitotic division, Kar3 protein was shown to localize to the spindle pole bodies. Finally, kar3 cells exhibited unstable or aberrant mitotic spindles, a finding that accounts for the delay in cell cycle progression and decreased viability of these cells. We suggest that the altered morphology of kar3 cells is a direct consequence of the delay in anaphase, and this leads to increased polarized growth and pseudohypha formation.
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Perfetto SP, Chattopadhyay PK, Lamoreaux L, Nguyen R, Ambrozak D, Koup RA, Roederer M. Amine reactive dyes: An effective tool to discriminate live and dead cells in polychromatic flow cytometry. J Immunol Methods 2006; 313:199-208. [PMID: 16756987 DOI: 10.1016/j.jim.2006.04.007] [Citation(s) in RCA: 171] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2006] [Accepted: 04/04/2006] [Indexed: 11/19/2022]
Abstract
Membrane-damaged cells caused by either mechanical trauma or through normal biological processes can produce artifacts in immunophenotyping analysis by flow cytometry. Dead cells can nonspecifically bind monoclonal antibody conjugates, potentially leading to erroneous conclusions, particularly when cell frequencies are low. To date, DNA intercalating dyes (Ethidium monoazaide (EMA), Propidium Iodide, 7AAD, etc.) or Annexin V have been commonly used to exclude dead cells; however, each suffer from technical problems. The first issue with such dyes is the dependence on a consistent dead cell source for fluorescence compensation. Another major issue is the stability of the staining; except for EMA, fixation and permeablization used for intracellular staining procedures can cause loss of fluorescence. EMA requires a UV exposure to covalently bond to DNA; while this dye is effective and is not affected by intracellular treatments it is weakly fluorescent. Here we report on the optimization of a new class of viability dyes, the amine reactive viability dyes (ViD) as a dead cell exclusion marker. The inclusion of ViD into the staining panel was found to be simple, reproducible and can have a significant benefit on the accuracy of identifying appropriate cell populations. We show the fluorescence of cells stained with these dyes correlates with traditional dead cell discriminating markers, even after fixation and permeabilization. Amine reactive viability dyes are a powerful tool for fluorescence immunophenotyping experiments.
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Affiliation(s)
- Stephen P Perfetto
- Immunology Laboratory, Vaccine Research Center, NIAID, NIH, 40 Convent Dr, Room 5509, Bethesda, MD 20892, USA
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Granzotto M, Leone V, Lepore L, Zerial M, Tommasini A, Ciambra R, Gombac F, Ventura A. Amantadine in chronic granulomatous disease. Pediatr Hematol Oncol 2005; 22:147-51. [PMID: 15805000 DOI: 10.1080/08880010590907267] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
Abstract
Chronic granulomatous disease (CGD) is a rare genetically determined immunodeficiency. Neutrophils from CGD patients show a defective killing of phagocytosed fungi and bacteria, due not only to an impairment in oxidative burst, but also to absence of normal pH value within phagocytic vacuole following phagocytosis. Because a weak base such as amantadine could potentially reverse these pH abnormalities, the authors used this drug to treat 2 CGD patients. They observed modifications of both phagosomal pH and killing activity on their neutrophils compared to those of healthy controls. Since the drug has been employed, the patients have not developed new infections, suggesting a role of amantadine as a part of CGD prophylactic regimen. These results suggest the opportunity of testing the drug in larger studies.
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Affiliation(s)
- David M. Coder
- University of Washington School of Medicine Seattle Washington
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Káposzta R, Maródi L, Hollinshead M, Gordon S, da Silva RP. Rapid recruitment of late endosomes and lysosomes in mouse macrophages ingesting Candida albicans. J Cell Sci 1999; 112 ( Pt 19):3237-48. [PMID: 10504329 DOI: 10.1242/jcs.112.19.3237] [Citation(s) in RCA: 69] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Candida albicans is an important opportunistic pathogen, whose interaction with cells of the immune system, in particular macrophages (MO), is poorly understood. In order to learn more about the nature of the infectious mechanism, internalisation of Candida albicans was studied in mouse MO by confocal immunofluorescence and electron microscopy in comparison with latex beads of similar size, which were coated with mannosyl-lipoarabinomannan (ManLAM) to target the MO mannose receptor (MR). Uptake of Candida yeasts had characteristics of phagocytosis, required intact actin filaments, and depended on the activity of protein kinase C (PKC). Candida phagosomes rapidly attracted lysosome-associated membrane protein (Lamp)-rich vacuoles, indicative of fusion with late endosomes and lysosomes. Rapid recruitment of late endosomes and lysosomes could be observed regardless of heat-inactivation or serum-opsonisation of Candida, but did not follow binding of the mannosylated-beads to MO, which suggest that this phenotype is not MR-specific. The yeasts developed germ tubes within phagolysosomes, distended their membranes and escaped, destroying the non-activated MO. The filamentous form of Candida could penetrate intact MO even when phagocytosis was blocked, and also attracted Lamp-rich organelles. Inhibition of lysosomal acidification and associated lysosomal fusion reduced germ tube formation of Candida within the phagolysosomes. These data suggest that rapid recruitment of late endocytic/lysosomal compartments by internalizing C. albicans favours survival and virulence of this pathogen.
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Affiliation(s)
- R Káposzta
- Department of Pediatrics, University School of Medicine, Debrecen, H-4012 Debrecen, POB: 32, Hungary
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Hjertstedt J, Hahn BL, Kos WL, Sohnle PG. Comparison of fungal viability assays using Candida albicans yeast cells undergoing prolonged incubation in the absence of nutrients. Mycoses 1998; 41:487-92. [PMID: 9919892 DOI: 10.1111/j.1439-0507.1998.tb00711.x] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
Staining methods for determining fungal viability are usually assessed by comparisons with enumeration of colony-forming units (CFU) on solid media. The purpose of the present study was to compare viability as assessed by the acridine orange (AO) and MTT methods with the numbers of CFUs obtained for Candida albicans yeast cells undergoing prolonged incubation in distilled water. In initial assessments of the assays using various proportions of control and heat-killed C. albicans, the AO and MTT methods consistently indicated significantly higher values for viability than did CFU determinations. Experiments using organisms cultured overnight revealed that approximately 95% of the cells were capable of dividing at least once in a microscopic proliferation assay, whereas only 69% were capable of forming colonies. Parallel assays comparing AO uptake and MTT reduction gave excellent agreement with the microscopic proliferation assay, but not with CFU determinations. Using organisms undergoing prolonged incubations in distilled water, much lower viabilities were obtained with the CFU method at 7 and 10 days than with the microscopic proliferation assay or the two staining methods. These results indicate that the AO and MTT assays correlate well with the ability of C. albicans to divide at least once, but may not accurately indicate the percentage of organisms actually able to form colonies.
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Affiliation(s)
- J Hjertstedt
- Department of Medicine, Medical College of Wisconsin, Milwaukee, USA
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Abstract
Yeast suspensions were analysed by flow cytometry after dye staining for determination of total and viable cell densities. Results were comparable to traditional colony counting and, in addition, provided further information on the percentage of total cells that were viable. The flow cytometric methods provided results within 20 min whereas colony counts were not available until 36 h. We evaluated a number of fluorescent dyes: ChemChrome Y (CY), oxonol (Ox), propidium iodide (PI), Fungolight and rhodamine 123, for accurate determination of viability of industrial yeast cultures and freshly re-hydrated high activity dried yeast (HADY). PI, Ox and CY gave the most conclusive live/dead discrimination and were the simplest to use. Culturing after dye staining and cell sorting demonstrated that the yeast remained viable after cell sorting and incubation with PI, CY or Ox. The methods, therefore, permit physical selection of individual yeast cells from populations of mixed viability. Sorting demonstrated that PI stained non-culturable cells whilst CY stained culturable cells. Analysis of yeast stained simultaneously with CY and PI or with Ox and PI demonstrated that PI and CY assays were in mutual agreement with respect to viability assessments. The Ox assay was in agreement with CY and PI for live/heat-killed mixtures. However, for re-hydrated HADY, Ox stained a significantly (P < or = 0.05) higher proportion of cells than did PI.
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Affiliation(s)
- D Deere
- Macquarie University Centre for Analytical Biotechnology, School of Biological Sciences, Macquarie University, NSW, Australia.
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