Intravital Imaging of Candida albicans Identifies Differential In Vitro and In Vivo Filamentation Phenotypes for Transcription Factor Deletion Mutants

Candida albicans is one of the most common causes of fungal infections in humans. C. albicans undergoes a transition from a round yeast form to a filamentous form during infection, which is critical for its ability to cause disease. Although this transition has been studied in the laboratory for years, methods to do so in an animal model of infection have been limited.

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Acetylcholine Protects against Candida albicans Infection by Inhibiting Biofilm Formation and Promoting Hemocyte Function in a Galleria mellonella Infection Model

Eukaryotic Cell ◽

10.1128/ec.00067-15 ◽

2015 ◽

Vol 14 (8) ◽

pp. 834-844 ◽

Cited By ~ 32

Author(s):

Ranjith Rajendran ◽

Elisa Borghi ◽

Monica Falleni ◽

Federica Perdoni ◽

Delfina Tosi ◽

...

Keyword(s):

Candida Albicans ◽

Biofilm Formation ◽

Galleria Mellonella ◽

Inflammatory Responses ◽

Fungal Infections ◽

Infection Model ◽

Content Type

ABSTRACT Both neuronal acetylcholine and nonneuronal acetylcholine have been demonstrated to modulate inflammatory responses. Studies investigating the role of acetylcholine in the pathogenesis of bacterial infections have revealed contradictory findings with regard to disease outcome. At present, the role of acetylcholine in the pathogenesis of fungal infections is unknown. Therefore, the aim of this study was to determine whether acetylcholine plays a role in fungal biofilm formation and the pathogenesis of Candida albicans infection. The effect of acetylcholine on C. albicans biofilm formation and metabolism in vitro was assessed using a crystal violet assay and phenotypic microarray analysis. Its effect on the outcome of a C. albicans infection, fungal burden, and biofilm formation were investigated in vivo using a Galleria mellonella infection model. In addition, its effect on modulation of host immunity to C. albicans infection was also determined in vivo using hemocyte counts, cytospin analysis, larval histology, lysozyme assays, hemolytic assays, and real-time PCR. Acetylcholine was shown to have the ability to inhibit C. albicans biofilm formation in vitro and in vivo . In addition, acetylcholine protected G. mellonella larvae from C. albicans infection mortality. The in vivo protection occurred through acetylcholine enhancing the function of hemocytes while at the same time inhibiting C. albicans biofilm formation. Furthermore, acetylcholine also inhibited inflammation-induced damage to internal organs. This is the first demonstration of a role for acetylcholine in protection against fungal infections, in addition to being the first report that this molecule can inhibit C. albicans biofilm formation. Therefore, acetylcholine has the capacity to modulate complex host-fungal interactions and plays a role in dictating the pathogenesis of fungal infections.

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Eap1p, an Adhesin That Mediates Candida albicans Biofilm Formation In Vitro and In Vivo

Eukaryotic Cell ◽

10.1128/ec.00049-07 ◽

2007 ◽

Vol 6 (6) ◽

pp. 931-939 ◽

Cited By ~ 96

Author(s):

Fang Li ◽

Michael J. Svarovsky ◽

Amy J. Karlsson ◽

Joel P. Wagner ◽

Karen Marchillo ◽

...

Keyword(s):

Candida Albicans ◽

Cell Adhesion ◽

Biofilm Formation ◽

Fungal Infections ◽

Gene Dosage ◽

Venous Catheter ◽

Flow Chamber ◽

Dependent Manner

ABSTRACT Candida albicans is the leading cause of systemic fungal infections in immunocompromised humans. The ability to form biofilms on surfaces in the host or on implanted medical devices enhances C. albicans virulence, leading to antimicrobial resistance and providing a reservoir for infection. Biofilm formation is a complex multicellular process consisting of cell adhesion, cell growth, morphogenic switching between yeast form and filamentous states, and quorum sensing. Here we describe the role of the C. albicans EAP1 gene, which encodes a glycosylphosphatidylinositol-anchored, glucan-cross-linked cell wall protein, in adhesion and biofilm formation in vitro and in vivo. Deleting EAP1 reduced cell adhesion to polystyrene and epithelial cells in a gene dosage-dependent manner. Furthermore, EAP1 expression was required for C. albicans biofilm formation in an in vitro parallel plate flow chamber model and in an in vivo rat central venous catheter model. EAP1 expression was upregulated in biofilm-associated cells in vitro and in vivo. Our results illustrate an association between Eap1p-mediated adhesion and biofilm formation in vitro and in vivo.

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The Novel Arylamidine T-2307 MaintainsIn VitroandIn VivoActivity against Echinocandin-Resistant Candida albicans

Antimicrobial Agents and Chemotherapy ◽

10.1128/aac.04228-14 ◽

2014 ◽

Vol 59 (2) ◽

pp. 1341-1343 ◽

Cited By ~ 14

Author(s):

Nathan P. Wiederhold ◽

Laura K. Najvar ◽

Annette W. Fothergill ◽

Rosie Bocanegra ◽

Marcos Olivo ◽

...

Keyword(s):

Body Weight ◽

Candida Albicans ◽

Invasive Candidiasis ◽

Placebo Control ◽

The Novel ◽

Content Type ◽

Fungal Burden ◽

Potential Use

ABSTRACTWe evaluated thein vitroandin vivoactivities of the investigational arylamidine T-2307 against echinocandin-resistantCandida albicans. T-2307 demonstrated potentin vitroactivity, and daily subcutaneous doses between 0.75 and 6 mg/kg of body weight significantly improved survival and reduced fungal burden compared to placebo control and caspofungin (10 mg/kg/day) in mice with invasive candidiasis caused by an echinocandin-resistant strain. Thus, T-2307 may have potential use in the treatment of echinocandin-resistantC. albicansinfections.

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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 VitroandIn VivoEvaluation of APX001A/APX001 and Other Gwt1 Inhibitors againstCryptococcus

Antimicrobial Agents and Chemotherapy ◽

10.1128/aac.00523-18 ◽

2018 ◽

Vol 62 (8) ◽

Cited By ~ 34

Author(s):

Karen Joy Shaw ◽

Wiley A. Schell ◽

Jonathan Covel ◽

Gisele Duboc ◽

C. Giamberardino ◽

...

Keyword(s):

Brain Tissue ◽

Lung Tissue ◽

Fungal Infections ◽

Treatment Options ◽

Content Type ◽

Fungal Burden ◽

Geographical Regions ◽

Current Therapies

ABSTRACTCryptococcal meningitis (CM), caused primarily byCryptococcus neoformans, is uniformly fatal if not treated. Treatment options are limited, especially in resource-poor geographical regions, and mortality rates remain high despite current therapies. Here we evaluated thein vitroandin vivoactivity of several compounds, including APX001A and its prodrug, APX001, currently in clinical development for the treatment of invasive fungal infections. These compounds target the conserved Gwt1 enzyme that is required for the localization of glycosylphosphatidylinositol (GPI)-anchored cell wall mannoproteins in fungi. The Gwt1 inhibitors had low MIC values, ranging from 0.004 μg/ml to 0.5 μg/ml, against bothC. neoformansandC. gattii. APX001A and APX2020 demonstratedin vitrosynergy with fluconazole (fractional inhibitory concentration index, 0.37 for both). In a CM model, APX001 and fluconazole each alone reduced the fungal burden in brain tissue (0.78 and 1.04 log10CFU/g, respectively), whereas the combination resulted in a reduction of 3.52 log10CFU/g brain tissue. Efficacy, as measured by a reduction in the brain and lung tissue fungal burden, was also observed for another Gwt1 inhibitor prodrug, APX2096, where dose-dependent reductions in the fungal burden ranged from 5.91 to 1.79 log10CFU/g lung tissue and from 7.00 and 0.92 log10CFU/g brain tissue, representing the nearly complete or complete sterilization of lung and brain tissue at the higher doses. These data support the further clinical evaluation of this new class of antifungal agents for the treatment of CM.

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Targeting Fibronectin To Disrupt In Vivo Candida albicans Biofilms

Antimicrobial Agents and Chemotherapy ◽

10.1128/aac.03094-15 ◽

2016 ◽

Vol 60 (5) ◽

pp. 3152-3155 ◽

Cited By ~ 7

Author(s):

Jeniel E. Nett ◽

Jonathan Cabezas-Olcoz ◽

Karen Marchillo ◽

Deane F. Mosher ◽

David R. Andes

Keyword(s):

Candida Albicans ◽

Biofilm Formation ◽

Drug Targets ◽

Venous Catheter ◽

Surface Adhesion ◽

Inhibitory Protein ◽

Content Type ◽

Novel Target

ABSTRACTNew drug targets are of great interest for the treatment of fungal biofilms, which are routinely resistant to antifungal therapies. We theorized that the interaction ofCandida albicanswith matricellular host proteins would provide a novel target. Here, we show that an inhibitory protein (FUD) targetingCandida-fibronectin interactions disrupts biofilm formationin vitroandin vivoin a rat venous catheter model. The peptide appears to act by blocking the surface adhesion ofCandida, halting biofilm formation.

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Symbiotic Relationship between Streptococcus mutans and Candida albicans Synergizes Virulence of Plaque BiofilmsIn Vivo

Infection and Immunity ◽

10.1128/iai.00087-14 ◽

2014 ◽

Vol 82 (5) ◽

pp. 1968-1981 ◽

Cited By ~ 216

Author(s):

Megan L. Falsetta ◽

Marlise I. Klein ◽

Punsiri M. Colonne ◽

Kathleen Scott-Anne ◽

Stacy Gregoire ◽

...

Keyword(s):

Candida Albicans ◽

Dental Caries ◽

Streptococcus Mutans ◽

Bacterial Pathogen ◽

Single Species ◽

Content Type ◽

3 Dimensional ◽

Biofilm Development

ABSTRACTStreptococcus mutansis often cited as the main bacterial pathogen in dental caries, particularly in early-childhood caries (ECC).S. mutansmay not act alone;Candida albicanscells are frequently detected along with heavy infection byS. mutansin plaque biofilms from ECC-affected children. It remains to be elucidated whether this association is involved in the enhancement of biofilm virulence. We showed that the ability of these organisms together to form biofilms is enhancedin vitroandin vivo. The presence ofC. albicansaugments the production of exopolysaccharides (EPS), such that cospecies biofilms accrue more biomass and harbor more viableS. mutanscells than single-species biofilms. The resulting 3-dimensional biofilm architecture displays sizeableS. mutansmicrocolonies surrounded by fungal cells, which are enmeshed in a dense EPS-rich matrix. Using a rodent model, we explored the implications of this cross-kingdom interaction for the pathogenesis of dental caries. Coinfected animals displayed higher levels of infection and microbial carriage within plaque biofilms than animals infected with either species alone. Furthermore, coinfection synergistically enhanced biofilm virulence, leading to aggressive onset of the disease with rampant carious lesions. Ourin vitrodata also revealed that glucosyltransferase-derived EPS is a key mediator of cospecies biofilm development and that coexistence withC. albicansinduces the expression of virulence genes inS. mutans(e.g.,gtfB,fabM). We also found thatCandida-derived β1,3-glucans contribute to the EPS matrix structure, while fungal mannan and β-glucan provide sites for GtfB binding and activity. Altogether, we demonstrate a novel mutualistic bacterium-fungus relationship that occurs at a clinically relevant site to amplify the severity of a ubiquitous infectious disease.

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Oral Administration of the Broad-Spectrum Antibiofilm Compound Toremifene Inhibits Candida albicans and Staphylococcus aureus Biofilm FormationIn Vivo

Antimicrobial Agents and Chemotherapy ◽

10.1128/aac.03869-14 ◽

2014 ◽

Vol 58 (12) ◽

pp. 7606-7610 ◽

Cited By ~ 16

Author(s):

Kaat De Cremer ◽

Nicolas Delattin ◽

Katrijn De Brucker ◽

Annelies Peeters ◽

Soña Kucharíková ◽

...

Keyword(s):

Staphylococcus Aureus ◽

Candida Albicans ◽

Broad Spectrum ◽

Staphylococcus Epidermidis ◽

Biofilm Formation ◽

Candida Krusei ◽

Content Type ◽

And Staphylococcus Aureus

ABSTRACTWe here report on thein vitroactivity of toremifene to inhibit biofilm formation of different fungal and bacterial pathogens, includingCandida albicans,Candida glabrata,Candida dubliniensis,Candida krusei,Pseudomonas aeruginosa,Staphylococcus aureus, andStaphylococcus epidermidis. We validated thein vivoefficacy of orally administered toremifene againstC. albicans and S. aureusbiofilm formation in a rat subcutaneous catheter model. Combined, our results demonstrate the potential of toremifene as a broad-spectrum oral antibiofilm compound.

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Deletion of the ATP2 Gene in Candida albicans Blocks Its Escape From Macrophage Clearance

Frontiers in Cellular and Infection Microbiology ◽

10.3389/fcimb.2021.643121 ◽

2021 ◽

Vol 11 ◽

Author(s):

Yishan Zhang ◽

Chuanyan Tang ◽

Zhanpeng Zhang ◽

Shuixiu Li ◽

Yajing Zhao ◽

...

Keyword(s):

Candida Albicans ◽

Drug Target ◽

Fungal Infections ◽

Carbon Sources ◽

Systemic Infection ◽

Invasive Infection ◽

First Line ◽

Dramatic Decrease

Macrophages provide the first-line defense against invasive fungal infections and, therefore, escape from macrophage becomes the basis for the establishment of Candida albicans invasive infection. Here, we found that deletion of ATP2 (atp2Δ/Δ) in C. albicans resulted in a dramatic decrease from 69.2% (WT) to 1.2% in the escape rate in vitro. The effect of ATP2 on macrophage clearance stands out among the genes currently known to affect clearance. In the normal mice, the atp2Δ/Δ cells were undetectable in major organs 72 h after systemic infection, while WT cells persisted in vivo. However, in the macrophage-depleted mice, atp2Δ/Δ could persist for 72 h at an amount comparable to that at 24 h. Regarding the mechanism, WT cells sustained growth and switched to hyphal form, which was more conducive to escape from macrophages, in media that mimic the glucose-deficient environment in macrophages. In contrast, atp2Δ/Δ cells can remained viable but were unable to complete morphogenesis in these media, resulting in them being trapped within macrophages in the yeast form. Meanwhile, atp2Δ/Δ cells were killed by oxidative stress in alternative carbon sources by 2- to 3-fold more than WT cells. Taken together, ATP2 deletion prevents C. albicans from escaping macrophage clearance, and therefore ATP2 has a functional basis as a drug target that interferes with macrophage clearance.

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The fungal-specific subunit i/j of F1FO-ATP synthase stimulates the pathogenicity of Candida albicans independent of oxidative phosphorylation

Medical Mycology ◽

10.1093/mmy/myaa094 ◽

2020 ◽

Author(s):

Yajing Zhao ◽

Yan Lyu ◽

Yanli Zhang ◽

Shuixiu Li ◽

Yishan Zhang ◽

...

Keyword(s):

Cell Wall ◽

Candida Albicans ◽

Oxidative Phosphorylation ◽

Atp Synthase ◽

Fungal Infections ◽

Critical Role ◽

Antifungal Drug ◽

F1fo Atp Synthase

Abstract Invasive fungal infections are a major cause of human mortality due in part to a very limited antifungal drug arsenal. The identification of fungal-specific pathogenic mechanisms is considered a crucial step to current antifungal drug development and represents a significant goal to increase the efficacy and reduce host toxicity. Although the overall architecture of F1FO-ATP synthase is largely conserved in both fungi and mammals, the subunit i/j (Su i/j, Atp18) and subunit k (Su k, Atp19) are proteins not found in mammals and specific to fungi. Here, the role of Su i/j and Su k in Candida albicans was characterized by an in vivo assessment of the virulence and in vitro growth and mitochondrial function. Strikingly, the atp18Δ/Δ mutant showed significantly reduced pathogenicity in systemic murine model. However, this substantial defect in infectivity exists without associated defects in mitochondrial oxidative phosphorylation or proliferation in vitro. Analysis of virulence-related traits reveals normal in both mutants, but shows cell wall defects in composition and architecture in the case of atp18Δ/Δ. We also find that the atp18Δ/Δ mutant is more susceptible to attack by macrophages than wild type, which may correlate well with the abnormal cell wall function and increased sensitivity to oxidative stress. In contrast, no significant changes were observed in any of these studies for the atp19Δ/Δ. These results demonstrate that the fungal-specific Su i/j, but not Su k of F1FO-ATP synthase may play a critical role in C. albicans infectivity and represent another opportunity for new therapeutic target investigation. Lay Abstract This study aims to investigate biological functions of fungal-specific subunit i/j and subunit k of ATP synthase in C. albicans oxidative phosphorylation and virulence potential. Our results revealed that subunit i/j, and not subunit k, is critical for C. albicans pathogenicity.

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