Antifungal Activity of Mammalian Serum Amyloid A1 against Candida albicans

ABSTRACT Mammalian serum amyloid A (SAA) is a major acute phase protein that shows a massive increase in plasma concentration during inflammation. In the present study, we demonstrate that the expression of mouse SAA1 in serum was increased when infected with Candida albicans, a major human fungal pathogen, in a systemic infection model. We then set out to investigate the antifungal activity of SAA proteins against C. albicans. Recombinant human and mouse SAA1 (rhSAA1 and rmSAA1) were expressed and purified in Escherichia coli. Both rhSAA1 and rmSAA1 exhibited a potent antifungal activity against C. albicans. We further demonstrate that rhSAA1 binds to the cell surface of C. albicans, disrupts cell membrane integrity, and induces rapid fungal cell death in C. albicans. Our finding expands the known functions of SAA1 and provides new insight into host-Candida interactions during fungal infection.

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Antifungal and Antibiofilm Activities and the Mechanism of Action of Repeating Lysine-Tryptophan Peptides against Candida albicans

Microorganisms ◽

10.3390/microorganisms8050758 ◽

2020 ◽

Vol 8 (5) ◽

pp. 758

Author(s):

Gopal Ramamourthy ◽

Jonggwan Park ◽

Changho Seo ◽

Hans J. Vogel ◽

Yoonkyung Park

Keyword(s):

Candida Albicans ◽

Antifungal Activity ◽

Laser Scanning ◽

Membrane Integrity ◽

Laser Scanning Confocal Microscopy ◽

Health Concern ◽

Cellular Functions ◽

Fungal Cell ◽

Scanning Confocal Microscopy ◽

Keratinocyte Cell

The rapid increase in the emergence of antifungal-resistant Candida albicans strains is becoming a serious health concern. Because antimicrobial peptides (AMPs) may provide a potential alternative to conventional antifungal agents, we have synthesized a series of peptides with a varying number of lysine and tryptophan repeats (KWn-NH2). The antifungal activity of these peptides increased with peptide length, but only the longest KW5 peptide displayed cytotoxicity towards a human keratinocyte cell line. The KW4 and KW5 peptides exhibited strong antifungal activity against C. albicans, even under conditions of high-salt and acidic pH, or the addition of fungal cell wall components. Moreover, KW4 inhibited biofilm formation by a fluconazole-resistant C. albicans strain. Circular dichroism and fluorescence spectroscopy indicated that fungal liposomes could interact with the longer peptides but that they did not release the fluorescent dye calcein. Subsequently, fluorescence assays with different dyes revealed that KW4 did not disrupt the membrane integrity of intact fungal cells. Scanning electron microscopy showed no changes in fungal morphology, while laser-scanning confocal microscopy indicated that KW4 can localize into the cytosol of C. albicans. Gel retardation assays revealed that KW4 can bind to fungal RNA as a potential intracellular target. Taken together, our data indicate that KW4 can inhibit cellular functions by binding to RNA and DNA after it has been translocated into the cell, resulting in the eradication of C. albicans.

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The Als3 Cell Wall Adhesin Plays a Critical Role in Human Serum Amyloid A1-Induced Cell Death and Aggregation in Candida albicans

Antimicrobial Agents and Chemotherapy ◽

10.1128/aac.00024-20 ◽

2020 ◽

Vol 64 (6) ◽

Author(s):

Jiao Gong ◽

Jian Bing ◽

Guobo Guan ◽

Clarissa J. Nobile ◽

Guanghua Huang

Keyword(s):

Cell Death ◽

Cell Wall ◽

Candida Albicans ◽

Critical Role ◽

Membrane Integrity ◽

Cell Aggregation ◽

Serum Amyloid ◽

Mouse Serum ◽

Content Type ◽

Serum Amyloid A1

ABSTRACT Antimicrobial peptides and proteins play critical roles in the host defense against invading pathogens. We recently discovered that recombinantly expressed human and mouse serum amyloid A1 (rhSAA1 and rmSAA1, respectively) proteins have potent antifungal activities against the major human fungal pathogen Candida albicans. At high concentrations, rhSAA1 disrupts C. albicans membrane integrity and induces rapid fungal cell death. In the present study, we find that rhSAA1 promotes cell aggregation and targets the C. albicans cell wall adhesin Als3. Inactivation of ALS3 in C. albicans leads to a striking decrease in cell aggregation and cell death upon rhSAA1 treatment, suggesting that Als3 plays a critical role in SAA1 sensing. We further demonstrate that deletion of the transcriptional regulators controlling the expression of ALS3, such as AHR1, BCR1, and EFG1, in C. albicans results in similar effects to that of the als3/als3 mutant upon rhSAA1 treatment. Global gene expression profiling indicates that rhSAA1 has a discernible impact on the expression of cell wall- and metabolism-related genes, suggesting that rhSAA1 treatment could lead to a nutrient starvation effect on C. albicans cells.

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Ibuprofen Potentiates theIn VivoAntifungal Activity of Fluconazole against Candida albicans Murine Infection

Antimicrobial Agents and Chemotherapy ◽

10.1128/aac.05056-14 ◽

2015 ◽

Vol 59 (7) ◽

pp. 4289-4292 ◽

Cited By ~ 13

Author(s):

Sofia Costa-de-Oliveira ◽

Isabel M. Miranda ◽

Ana Silva-Dias ◽

Ana P. Silva ◽

Acácio G. Rodrigues ◽

...

Keyword(s):

Candida Albicans ◽

Antifungal Activity ◽

Murine Model ◽

Resistant Strain ◽

Efflux Pump ◽

Systemic Infection ◽

New Approach ◽

Content Type ◽

Fungal Burden ◽

Fluconazole Resistant

ABSTRACTCandida albicansis the most prevalent cause of fungemia worldwide. Its ability to develop resistance in patients receiving azole antifungal therapy is well documented. In a murine model of systemic infection, we show that ibuprofen potentiates fluconazole antifungal activity against a fluconazole-resistant strain, drastically reducing the fungal burden and morbidity. The therapeutic combination of fluconazole with ibuprofen may constitute a new approach for the management of antifungal therapeutics to reverse the resistance conferred by efflux pump overexpression.

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Comparative Transcript Profiling of Candida albicans and Candida dubliniensis Identifies SFL2, a C. albicans Gene Required for Virulence in a Reconstituted Epithelial Infection Model

Eukaryotic Cell ◽

10.1128/ec.00291-09 ◽

2009 ◽

Vol 9 (2) ◽

pp. 251-265 ◽

Cited By ~ 55

Author(s):

Martin J. Spiering ◽

Gary P. Moran ◽

Murielle Chauvel ◽

Donna M. MacCallum ◽

Judy Higgins ◽

...

Keyword(s):

Candida Albicans ◽

Virulence Genes ◽

Systemic Infection ◽

Global Gene Expression ◽

Candida Dubliniensis ◽

Yeast Cells ◽

Infection Model ◽

Oral Epithelium ◽

Content Type ◽

Rapid Induction

ABSTRACT Candida albicans and Candida dubliniensis are closely related species displaying differences in virulence and genome content, therefore providing potential opportunities to identify novel C. albicans virulence genes. C. albicans gene arrays were used for comparative analysis of global gene expression in the two species in reconstituted human oral epithelium (RHE). C. albicans (SC5314) showed upregulation of hypha-specific and virulence genes within 30 min postinoculation, coinciding with rapid induction of filamentation and increased RHE damage. C. dubliniensis (CD36) showed no detectable upregulation of hypha-specific genes, grew as yeast, and caused limited RHE damage. Several genes absent or highly divergent in C. dubliniensis were upregulated in C. albicans. One such gene, SFL2 (orf19.3969), encoding a putative heat shock factor, was deleted in C. albicans. ΔΔsfl2 cells failed to filament under a range of hypha-inducing conditions and exhibited greatly reduced RHE damage, reversed by reintroduction of SFL2 into the ΔΔsfl2 strain. Moreover, SFL2 overexpression in C. albicans triggered hyphal morphogenesis. Although SFL2 deletion had no apparent effect on host survival in the murine model of systemic infection, ΔΔsfl2 strain-infected kidney tissues contained only yeast cells. These results suggest a role for SFL2 in morphogenesis and an indirect role in C. albicans pathogenesis in epithelial tissues.

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Synergistic Activity of the Tyrocidines, Antimicrobial Cyclodecapeptides from Bacillus aneurinolyticus, with Amphotericin B and Caspofungin against Candida albicans Biofilms

Antimicrobial Agents and Chemotherapy ◽

10.1128/aac.02381-14 ◽

2014 ◽

Vol 58 (7) ◽

pp. 3697-3707 ◽

Cited By ~ 33

Author(s):

Anscha Mari Troskie ◽

Marina Rautenbach ◽

Nicolas Delattin ◽

Johan Arnold Vosloo ◽

Margitta Dathe ◽

...

Keyword(s):

Candida Albicans ◽

Amphotericin B ◽

Membrane Integrity ◽

Antifungal Drugs ◽

Infection Model ◽

Synergistic Activity ◽

Significant Activity ◽

Content Type ◽

Micromolar Range

ABSTRACTTyrocidines are cationic cyclodecapeptides fromBacillus aneurinolyticusthat are characterized by potent antibacterial and antimalarial activities. In this study, we show that various tyrocidines have significant activity against planktonicCandida albicansin the low-micromolar range. These tyrocidines also preventedC. albicansbiofilm formationin vitro. Studies with the membrane-impermeable dye propidium iodide showed that the tyrocidines disrupt the membrane integrity of matureC. albicansbiofilm cells. This membrane activity correlated with the permeabilization and rapid lysis of model fungal membranes containing phosphatidylcholine and ergosterol (70:30 ratio) induced by the tyrocidines. The tyrocidines exhibited pronounced synergistic biofilm-eradicating activity in combination with two key antifungal drugs, amphotericin B and caspofungin. Using aCaenorhabditis elegansinfection model, we found that tyrocidine A potentiated the activity of caspofungin. Therefore, tyrocidines are promising candidates for further research as antifungal drugs and as agents for combinatorial treatment.

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The newly synthesized thiazole derivatives as potential antifungal compounds against Candida albicans

Applied Microbiology and Biotechnology ◽

10.1007/s00253-021-11477-7 ◽

2021 ◽

Author(s):

Anna Biernasiuk ◽

Anna Berecka-Rycerz ◽

Anna Gumieniczek ◽

Maria Malm ◽

Krzysztof Z. Łączkowski ◽

...

Keyword(s):

Cell Wall ◽

Candida Albicans ◽

Antifungal Activity ◽

Cell Membrane ◽

Mode Of Action ◽

Thiazole Derivatives ◽

Fungal Cell ◽

Erythrocyte Lysis ◽

Low Cytotoxicity ◽

High Antifungal Activity

Abstract Recently, the occurrence of candidiasis has increased dramatically, especially in immunocompromised patients. Additionally, their treatment is often ineffective due to the resistance of yeasts to antimycotics. Therefore, there is a need to search for new antifungals. A series of nine newly synthesized thiazole derivatives containing the cyclopropane system, showing promising activity against Candida spp., has been further investigated. We decided to verify their antifungal activity towards clinical Candida albicans isolated from the oral cavity of patients with hematological malignancies and investigate the mode of action on fungal cell, the effect of combination with the selected antimycotics, toxicity to erythrocytes, and lipophilicity. These studies were performed by the broth microdilution method, test with sorbitol and ergosterol, checkerboard technique, erythrocyte lysis assay, and reversed phase thin-layer chromatography, respectively. All derivatives showed very strong activity (similar and even higher than nystatin) against all C. albicans isolates with minimal inhibitory concentration (MIC) = 0.008–7.81 µg/mL Their mechanism of action may be related to action within the fungal cell wall structure and/or within the cell membrane. The interactions between the derivatives and the selected antimycotics (nystatin, chlorhexidine, and thymol) showed additive effect only in the case of combination some of them and thymol. The erythrocyte lysis assay confirmed the low cytotoxicity of these compounds as compared to nystatin. The high lipophilicity of the derivatives was related with their high antifungal activity. The present studies confirm that the studied thiazole derivatives containing the cyclopropane system appear to be a very promising group of compounds in treatment of infections caused by C. albicans. However, this requires further studies in vivo. Key points • The newly thiazoles showed high antifungal activity and some of them — additive effect in combination with thymol. • Their mode of action may be related with the influence on the structure of the fungal cell wall and/or the cell membrane. • The low cytotoxicity against erythrocytes and high lipophilicity of these derivatives are their additional good properties. Graphical abstract

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Identification and Characterization of TUP1-Regulated Genes in Candida albicans

Genetics ◽

10.1093/genetics/156.1.31 ◽

2000 ◽

Vol 156 (1) ◽

pp. 31-44 ◽

Cited By ~ 7

Author(s):

Burkhard R Braun ◽

W Steven Head ◽

Ming X Wang ◽

Alexander D Johnson

Keyword(s):

Candida Albicans ◽

Systemic Infection ◽

Subtractive Hybridization ◽

Filamentous Growth ◽

Surface Proteins ◽

Infection Model ◽

Ferric Reductase ◽

Pathogenesis Related Protein ◽

Plant Pathogenesis ◽

Rnase T2

Abstract TUP1 encodes a transcriptional repressor that negatively controls filamentous growth in Candida albicans. Using subtractive hybridization, we identified six genes, termed repressed by TUP1 (RBT), whose expression is regulated by TUP1. One of the genes (HWP1) has previously been characterized, and a seventh TUP1-repressed gene (WAP1) was recovered due to its high similarity to RBT5. These genes all encode secreted or cell surface proteins, and four out of the seven (HWP1, RBT1, RBT5, and WAP1) encode putatively GPI-modified cell wall proteins. The remaining three, RBT2, RBT4, and RBT7, encode, respectively, an apparent ferric reductase, a plant pathogenesis-related protein (PR-1), and a putative secreted RNase T2. The expression of RBT1, RBT4, RBT5, HWP1, and WAP1 was induced in wild-type cells during the switch from the yeast form to filamentous growth, indicating the importance of TUP1 in regulating this process and implicating the RBTs in hyphal-specific functions. We produced knockout strains in C. albicans for RBT1, RBT2, RBT4, RBT5, and WAP1 and detected no phenotypes on several laboratory media. However, two animal models for C. albicans infection, a rabbit cornea model and a mouse systemic infection model, revealed that rbt1Δ and rbt4Δ strains had significantly reduced virulence. TUP1 appears, therefore, to regulate many genes in C. albicans, a significant fraction of which are induced during filamentous growth, and some of which participate in pathogenesis.

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Antimicrobial Photodynamic Inactivation Inhibits Candida albicans Virulence Factors and ReducesIn VivoPathogenicity

Antimicrobial Agents and Chemotherapy ◽

10.1128/aac.01451-12 ◽

2012 ◽

Vol 57 (1) ◽

pp. 445-451 ◽

Cited By ~ 41

Author(s):

Ilka Tiemy Kato ◽

Renato Araujo Prates ◽

Caetano Padial Sabino ◽

Beth Burgwyn Fuchs ◽

George P. Tegos ◽

...

Keyword(s):

Candida Albicans ◽

Virulence Factors ◽

Sodium Dodecyl ◽

Systemic Infection ◽

Tube Formation ◽

Photodynamic Inactivation ◽

Content Type ◽

Daughter Cells

ABSTRACTThe objective of this study was to evaluate whetherCandida albicansexhibits altered pathogenicity characteristics following sublethal antimicrobial photodynamic inactivation (APDI) and if such alterations are maintained in the daughter cells.C. albicanswas exposed to sublethal APDI by using methylene blue (MB) as a photosensitizer (0.05 mM) combined with a GaAlAs diode laser (λ 660 nm, 75 mW/cm2, 9 to 27 J/cm2).In vitro, we evaluated APDI effects onC. albicansgrowth, germ tube formation, sensitivity to oxidative and osmotic stress, cell wall integrity, and fluconazole susceptibility.In vivo, we evaluatedC. albicanspathogenicity with a mouse model of systemic infection. Animal survival was evaluated daily. Sublethal MB-mediated APDI reduced the growth rate and the ability ofC. albicansto form germ tubes compared to untreated cells (P< 0.05). Survival of mice systemically infected withC. albicanspretreated with APDI was significantly increased compared to mice infected with untreated yeast (P< 0.05). APDI increasedC. albicanssensitivity to sodium dodecyl sulfate, caffeine, and hydrogen peroxide. The MIC for fluconazole forC. albicanswas also reduced following sublethal MB-mediated APDI. However, none of those pathogenic parameters was altered in daughter cells ofC. albicanssubmitted to APDI. These data suggest that APDI may inhibit virulence factors and reducein vivopathogenicity ofC. albicans. The absence of alterations in daughter cells indicates that APDI effects are transitory. The MIC reduction for fluconazole following APDI suggests that this antifungal could be combined with APDI to treatC. albicansinfections.

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In Vitro Antifungal Activity of (1)-N-2-Methoxybenzyl-1,10-phenanthrolinium Bromide against Candida albicans and Its Effects on Membrane Integrity

Mycobiology ◽

10.5941/myco.2017.45.1.25 ◽

2017 ◽

Vol 45 (1) ◽

pp. 25-30 ◽

Cited By ~ 2

Author(s):

Setiawati Setiawati ◽

Titik Nuryastuti ◽

Ngatidjan Ngatidjan ◽

Mustofa Mustofa ◽

Jumina Jumina ◽

...

Keyword(s):

Candida Albicans ◽

Antifungal Activity ◽

Membrane Integrity ◽

In Vitro Antifungal Activity

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In Fungal Intracellular Pathogenesis, Form Determines Fate

mBio ◽

10.1128/mbio.02092-18 ◽

2018 ◽

Vol 9 (5) ◽

Cited By ~ 4

Author(s):

Robin C. May ◽

Arturo Casadevall

Keyword(s):

Candida Albicans ◽

Fungal Pathogen ◽

Membrane Integrity ◽

Pathogenic Fungi ◽

Morphological Transition ◽

Physical Damage ◽

Fungal Cell ◽

Morphological Transitions ◽

Pathogenic Microbes ◽

Phagosomal Membrane

ABSTRACT For pathogenic microbes to survive ingestion by macrophages, they must subvert powerful microbicidal mechanisms within the phagolysosome. After ingestion, Candida albicans undergoes a morphological transition producing hyphae, while the surrounding phagosome exhibits a loss of phagosomal acidity. However, how these two events are related has remained enigmatic. Now Westman et al. (mBio 9:e01226-18, 2018, https://doi.org/10.1128/mBio.01226-18) report that phagosomal neutralization results from disruption of phagosomal membrane integrity by the enlarging hyphae, directly implicating the morphological transition in physical damage that promotes intracellular survival. The C. albicans intracellular strategy shows parallels with another fungal pathogen, Cryptococcus neoformans, where a morphological changed involving capsular enlargement intracellularly is associated with loss of membrane integrity and death of the host cell. These similarities among distantly related pathogenic fungi suggest that morphological transitions that are common in fungi directly affect the outcome of the fungal cell-macrophage interaction. For this class of organisms, form determines fate in the intracellular environment.

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