Efficacy of Ebselen Against Invasive Aspergillosis in a Murine Model

Invasive aspergillosis is one of the major causes of morbidity and mortality among invasive fungal infections. The search for new antifungal drugs becomes imperative when existing drugs are not able to efficiently treat these infections. Ebselen, is an organoselenium compound, already successfully approved in clinical trials as a repositioned drug for the treatment of bipolar disorder and prevention of noise-induced hearing loss. In this study, we aimed to reposition ebselen for the treatment of invasive aspergillosis by showing ebselen effectiveness in a murine model. For this, BALB/c mice were immunosuppressed and infected systemically with Aspergillus fumigatus. Animals were divided and treated with ebselen, voriconazole, or drug-free control, for four days. The kidneys were used for CFU count and, histopathological and cytokine analysis. Ebselen was able to significantly reduce the fungal burden in the kidneys of infected mice with efficacy comparable with voriconazole treatment as both had reductions to the same extent. The absence of hyphae and intact kidney tissue structure observed in the histopathological sections analyzed from treated groups corroborate with the downregulation of IL-6 and TNF. In summary, this study brings for the first time in vivo evidence of ebselen efficacy against invasive aspergillosis. Despite these promising results, more animal studies are warranted to evaluate the potential role of ebselen as an alternative option for the management of invasive aspergillosis in humans.

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1346. The Tetrazole VT-1598 Is Efficacious in a Murine Model of Invasive Aspergillosis with a PK/PD Expected of a Mold-Active CYP51 Inhibitor

Open Forum Infectious Diseases ◽

10.1093/ofid/ofy210.1177 ◽

2018 ◽

Vol 5 (suppl_1) ◽

pp. S411-S412

Author(s):

Edward P Garvey ◽

Andrew Sharp ◽

Peter Warn ◽

Christopher M Yates ◽

Robert J Schotzinger

Keyword(s):

Antifungal Activity ◽

Invasive Aspergillosis ◽

Murine Model ◽

Pathogenic Fungi ◽

Rational Drug Design ◽

Fungal Burden ◽

Delayed Treatment ◽

Rational Drug

Abstract Background VT-1598 is a novel fungal CYP51 inhibitor with potent in vitro activity against yeast, mold, and endemic pathogenic fungi (Wiederhold, JAC, 2017). Its tetrazole-based rational drug design imparts much greater selectivity vs. human CYPs (Yates, BMCL, 2017), which could reduce human CYP-related side effects and DDIs. We report here VT-1598’s in vivo activity in an invasive aspergillosis (IA) model. Methods MIC was determined as outlined in CLSI M38-A2. Plasma PK was measured after 4 days of oral doses in neutropenic ICR mice without fungal inoculation. In vivo antifungal activity was determined in a tail-vein IA model in neutropenic mice inoculated with A. fumigatus (AF) ATCC 204305 (N = 10 per dose). Two separate studies were conducted, with oral VT-1598 treatment starting either 48 hours prior (prophylaxis) or 5 hours postinoculation (delayed), with 4 days of postinoculation dosing, and kidney fungal burden measured 1 day post last dose by both CFU and qPCR. Drug control was 10 mg/kg AmBisome i.v. Results The MIC for VT-1598 against AF 204305 was 0.25 μg/mL. The plasma PK of VT-1598 was linearly proportional between the 5 and 40 mg/kg once-daily doses, with AUCs of 155 and 1,033 μg h/mL for the two doses, respectively. VT-1598 was similarly effective in reducing fungal burden when given in delayed treatment compared with prophylaxis, and both studies demonstrated a full dose–response (i.e., no to full reduction of fungal burden). When comparing fungal burdens of each dose group to the fungal burden at the start of treatment, the dose of VT-1598 to achieve fungal stasis ranged from 20.5 to 25.9 mg/kg and to achieve a 1-log10 fungal kill ranged from 30.9 to 50.5 mg/kg. Using the previously measured mouse plasma binding (>99.9%), the free AUC /MIC values for stasis and 1-log10 kill ranged from 2.1–2.7 and 3.2–5.2, respectively. These values are within the range of 1–11 that have been reported for posaconazole and isavuconazole (Lepak, AAC, 2013). Conclusion VT-1598 had potent antifungal activity in a murine model of IA. The PK/PD relationship was the same as clinically used mold-active CYP51 agents, suggesting that it could have similar clinical efficacy. If correct, the tetrazole-based greater selectivity may significantly differentiate VT-1598 from current IA therapies. Disclosures E. P. Garvey, Viamet Pharmaceuticals, Inc.: Employee, Salary. A. Sharp, Evotec (UK) Ltd.: Employee, Salary. P. Warn, Evotec (UK) Ltd.: Employee, Salary. C. M. Yates, Viamet Pharmaceuticals, Inc.: Employee, Salary. R. J. Schotzinger, Viamet Pharmaceuticals, Inc.: Board Member and Employee, Salary.

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Marine Bioactive Compounds against Aspergillus fumigatus: Challenges and Future Prospects

Antibiotics ◽

10.3390/antibiotics9110813 ◽

2020 ◽

Vol 9 (11) ◽

pp. 813

Author(s):

Chukwuemeka Samson Ahamefule ◽

Blessing C. Ezeuduji ◽

James C. Ogbonna ◽

Anene N. Moneke ◽

Anthony C. Ike ◽

...

Keyword(s):

Mortality Rate ◽

Invasive Aspergillosis ◽

Aspergillus Fumigatus ◽

Bioactive Compounds ◽

Antifungal Agents ◽

Antifungal Drugs ◽

Marine Resources ◽

Future Prospects ◽

Speed Up

With the mortality rate of invasive aspergillosis caused by Aspergillus fumigatus reaching almost 100% among some groups of patients, and with the rapidly increasing resistance of A. fumigatus to available antifungal drugs, new antifungal agents have never been more desirable than now. Numerous bioactive compounds were isolated and characterized from marine resources. However, only a few exhibited a potent activity against A. fumigatus when compared to the multitude that did against some other pathogens. Here, we review the marine bioactive compounds that display a bioactivity against A. fumigatus. The challenges hampering the discovery of antifungal agents from this rich habitat are also critically analyzed. Further, we propose strategies that could speed up an efficient discovery and broaden the dimensions of screening in order to obtain promising in vivo antifungal agents with new modes of action.

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In Vivo Efficacy of Anidulafungin and Caspofungin against Candida glabrata and Association with In Vitro Potency in the Presence of Sera

Antimicrobial Agents and Chemotherapy ◽

10.1128/aac.00105-07 ◽

2007 ◽

Vol 51 (5) ◽

pp. 1616-1620 ◽

Cited By ~ 67

Author(s):

Nathan P. Wiederhold ◽

Laura K. Najvar ◽

Rosie Bocanegra ◽

Destiny Molina ◽

Marcos Olivo ◽

...

Keyword(s):

Candida Glabrata ◽

Animal Studies ◽

Kidney Tissue ◽

Vitro Activity ◽

In Vivo Studies ◽

In Vitro Activity ◽

In Vivo Efficacy ◽

Fungal Burden

ABSTRACT In vitro studies have demonstrated that anidulafungin has greater potency than caspofungin against Candida glabrata. However, data from in vivo studies demonstrating that it has superior efficacy are lacking. The objective of this study was to compare the activities of anidulafungin and caspofungin against C. glabrata in a murine model of disseminated candidiasis. Two clinical C. glabrata isolates were used, including one with reduced caspofungin susceptibility. MICs were determined by broth microdilution in the presence and absence of sera. For the animal studies, mice were immunosuppressed with 5-fluorouracil one day prior to intravenous inoculation. Treatment with anidulafungin and caspofungin (0, 0.5, 1, 5, and 10 mg/kg of body weight per day) was begun 24 h later and was continued through day 7 postinoculation. The CFU were enumerated from kidney tissue. According to the standard microdilution methodology, anidulafungin had superior in vitro activity. However, this enhanced potency was attenuated by the addition of mouse and human sera. Caspofungin reduced the kidney fungal burden at lower doses compared to that achieved with anidulafungin in mice infected with the isolate with the lower MIC. Against the strain with the elevated caspofungin MIC, both anidulafungin and caspofungin were effective in reducing the kidney fungal burden at the higher doses studied. Despite the greater in vitro activity of anidulafungin in the absence of sera, both echinocandins were similarly effective in reducing the fungal burden in kidney tissue. The superior in vitro activity of anidulafungin did not confer enhanced in vivo efficacy against C. glabrata.

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Identification of a New Class of Antifungals Targeting the Synthesis of Fungal Sphingolipids

mBio ◽

10.1128/mbio.00647-15 ◽

2015 ◽

Vol 6 (3) ◽

Cited By ~ 64

Author(s):

Visesato Mor ◽

Antonella Rella ◽

Amir M. Farnoud ◽

Ashutosh Singh ◽

Mansa Munshi ◽

...

Keyword(s):

Cell Cycle Progression ◽

Fungal Infections ◽

Pathogenic Fungi ◽

Antifungal Drugs ◽

Sequencing Analysis ◽

Fungal Cell ◽

New Class ◽

Narrow Spectrum

ABSTRACT Recent estimates suggest that >300 million people are afflicted by serious fungal infections worldwide. Current antifungal drugs are static and toxic and/or have a narrow spectrum of activity. Thus, there is an urgent need for the development of new antifungal drugs. The fungal sphingolipid glucosylceramide (GlcCer) is critical in promoting virulence of a variety of human-pathogenic fungi. In this study, we screened a synthetic drug library for compounds that target the synthesis of fungal, but not mammalian, GlcCer and found two compounds [N′-(3-bromo-4-hydroxybenzylidene)-2-methylbenzohydrazide (BHBM) and its derivative, 3-bromo-N′-(3-bromo-4-hydroxybenzylidene) benzohydrazide (D0)] that were highly effective in vitro and in vivo against several pathogenic fungi. BHBM and D0 were well tolerated in animals and are highly synergistic or additive to current antifungals. BHBM and D0 significantly affected fungal cell morphology and resulted in the accumulation of intracellular vesicles. Deep-sequencing analysis of drug-resistant mutants revealed that four protein products, encoded by genes APL5, COS111, MKK1, and STE2, which are involved in vesicular transport and cell cycle progression, are targeted by BHBM. IMPORTANCE Fungal infections are a significant cause of morbidity and mortality worldwide. Current antifungal drugs suffer from various drawbacks, including toxicity, drug resistance, and narrow spectrum of activity. In this study, we have demonstrated that pharmaceutical inhibition of fungal glucosylceramide presents a new opportunity to treat cryptococcosis and various other fungal infections. In addition to being effective against pathogenic fungi, the compounds discovered in this study were well tolerated by animals and additive to current antifungals. These findings suggest that these drugs might pave the way for the development of a new class of antifungals.

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Potential human immunotherapeutics for plague

Immunotherapy Advances ◽

10.1093/immadv/ltab020 ◽

2021 ◽

Author(s):

Voahangy Andrianaivoarimanana ◽

Lovasoa Nomena Randriantseheno ◽

Kristoffer M Moore ◽

Nicola J Walker ◽

Steven G Lonsdale ◽

...

Keyword(s):

Monoclonal Antibodies ◽

South America ◽

Yersinia Pestis ◽

Clinical Isolate ◽

Murine Model ◽

Post Infection ◽

Protective Efficacy ◽

First Time ◽

A Current

Abstract Two monoclonal antibodies directed to the V antigen of Yersinia pestis have been tested for protective efficacy in a murine model of bubonic plague. Mice were infected with a current clinical isolate from Madagascar, designated Y.pestis 10-21/S. Mab7.3, delivered to mice intra-periteoneally at either 24h prior to, or 24h post- infection, was fully protective, building on many studies which have demonstrated the protective efficacy of this Mab against a number of different clinical isolates of Y.pestis. Mab 29.3, delivered intra-peritoneally at either -24h or +24h, protected 4/5 mice in either condition; this has demonstrated the protective efficacy of this Mab in vivo for the first time. These results add to the cumulative data about Mab7.3, which is currently being humanized and highlight its potential as a human immunotherapeutic for plague, which is an enduring endemic disease in Madagascar and other regions of Africa, Asia and South America.

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Non-toxic Cobalt(III) Schiff Base Complexes with Broad Spectrum Antifungal Activity

10.26434/chemrxiv.12736505 ◽

2020 ◽

Author(s):

Angelo Frei ◽

A. Paden King ◽

Gabrielle J. Lowe ◽

Amy K. Cain ◽

Francesca L. Short ◽

...

Keyword(s):

Schiff Base ◽

Antifungal Activity ◽

Broad Spectrum ◽

Bacterial Infections ◽

Fungal Infections ◽

Antifungal Drugs ◽

New Drugs ◽

Schiff Base Complexes ◽

In Vivo Studies

Resistance to currently available antifungal drugs has quietly been on the rise but overshadowed by the alarming spread of antibacterial resistance. There is a striking lack of attention to the threat of drug resistant fungal infections, with only a handful of new drugs currently in development. Given that metal complexes have proven to be useful new chemotypes in the fight against diseases such as cancer, malaria, and bacterial infections, it stands to reason to explore their possible utility in treating fungal infections. Herein we report a series of cobalt(III) Schiff base complexes with broad spectrum antifungal activity. Some of these complexes (1-3) show minimum inhibitory concentrations (MIC) in the low micro- to nanomolar range against a series of Candida and Cryptococcus yeasts. Additionally, we demonstrate that these compounds show no cytotoxicity against both bacterial and human cells. Finally, we report first in vivo toxicity data on these compounds in Galleria mellonella, showing that doses as high as 266 mg/kg are tolerated without adverse effects, paving the way for further in vivo studies of these complexes. <br>

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Antifungal effect of all-trans retinoic acid against Aspergillus fumigatus in vitro and in a pulmonary aspergillosis in vivo model

Antimicrobial Agents and Chemotherapy ◽

10.1128/aac.01874-20 ◽

2020 ◽

Author(s):

Elena Campione ◽

Roberta Gaziano ◽

Elena Doldo ◽

Daniele Marino ◽

Mattia Falconi ◽

...

Keyword(s):

Retinoic Acid ◽

Aspergillus Fumigatus ◽

Rat Model ◽

Fungal Infections ◽

Invasive Pulmonary Aspergillosis ◽

Antifungal Drugs ◽

Pulmonary Aspergillosis ◽

Fungistatic Activity

AIM: Aspergillus fumigatus is the most common opportunistic fungal pathogen and causes invasive pulmonary aspergillosis (IPA), with high mortality among immunosuppressed patients. Fungistatic activity of all-trans retinoic acid (ATRA) has been recently described in vitro. We evaluated the efficacy of ATRA in vivo and its potential synergistic interaction with other antifungal drugs. MATERIALS AND METHODS: A rat model of IPA and in vitro experiments were performed to assess the efficacy of ATRA against Aspergillus in association with classical antifungal drugs and in silico studies used to clarify its mechanism of action. RESULTS: ATRA (0.5 and 1 mM) displayed a strong fungistatic activity in Aspergillus cultures, while at lower concentrations, synergistically potentiated fungistatic efficacy of sub-inhibitory concentration of Amphotericin B (AmB) and Posaconazole (POS). ATRA also enhanced macrophagic phagocytosis of conidia. In a rat model of IPA, ATRA reduced mortality similarly to Posaconazole. CONCLUSION: Fungistatic efficacy of ATRA alone and synergistically with other antifungal drugs was documented in vitro, likely by inhibiting fungal Hsp90 expression and Hsp90-related genes. ATRA reduced mortality in a model of IPA in vivo. Those findings suggest ATRA as suitable fungistatic agent, also to reduce dosage and adverse reaction of classical antifungal drugs, and new therapeutic strategies against IPA and systemic fungal infections.

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A second generation fungerp analog SCY-247, shows potent in vivo activity in a murine model of hematogenously disseminated Candida albicans

Antimicrobial Agents and Chemotherapy ◽

10.1128/aac.01989-20 ◽

2020 ◽

pp. AAC.01989-20

Author(s):

Sherman Chu ◽

Lisa Long ◽

Thomas S McCormick ◽

Katyna Borroto-Esoda ◽

Stephen Barat ◽

...

Keyword(s):

Survival Rate ◽

Murine Model ◽

Second Generation ◽

Fungal Infections ◽

Plasma Concentrations ◽

Survival Rates ◽

Multidrug Resistant ◽

Fungal Species ◽

First Line Therapy

Echinocandins are a first-line therapy for Candida infections through their ability to inhibit the synthesis of polymer ß-(1,3)-D-glucan. However, there has been an emergence of multidrug-resistant fungal species necessitating the development of novel antifungal agents to combat invasive fungal infections. SCY-247, a second-generation glucan synthase inhibitor of the triterpenoid class (fungerps), is currently being developed as a potential therapy option. We determined the pharmacokinetics of SCY-247 following oral (gavage) administration in mice and evaluated the efficacy of SCY-247 in a murine model of hematogenously disseminated candidiasis caused by C. albicans. Plasma concentrations of SCY-247 were measurable through the last collected time point in all dose groups. Mean concentrations of SCY-247 increased with dose levels, with concentrations of SCY-247 higher after multiple doses compared to a single dose. Treatment with SCY-247 resulted in decreased fungal burden and improvement in survival rates against C. albicans disseminated infection. Treatment with 10 mg/kg SCY-247 showed a significant reduction in CFUs compared to the untreated control (3-log decrease on average) (P=0.008). Similarly, SCY-247 40 mg/kg demonstrated a statistically significant reduction in kidney CFUs compared to untreated mice (average log CFU ± SD of 2.38 ± 2.58 vs 6.26 ± 0.51; P=0.001). Mice treated with SCY-247 at 40 mg/kg exhibited a 100% survival rate at the end of the study, contrasted with 62.5% (5 of 8) survival rate in untreated mice. The results of this investigation indicate that SCY-247 is a promising novel anti-fungal agent with activity against Candida infections.

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Identification of Essential Genes in the Human Fungal Pathogen Aspergillus fumigatus by Transposon Mutagenesis

Eukaryotic Cell ◽

10.1128/ec.2.2.247-255.2003 ◽

2003 ◽

Vol 2 (2) ◽

pp. 247-255 ◽

Cited By ~ 48

Author(s):

Arnaud Firon ◽

François Villalba ◽

Roland Beffa ◽

Christophe d'Enfert

Keyword(s):

Aspergillus Fumigatus ◽

Transposable Element ◽

Drug Targets ◽

Fungal Infections ◽

Fungal Growth ◽

Developed Countries ◽

Transposon Mutagenesis ◽

Essential Genes ◽

Antifungal Drugs

ABSTRACT The opportunistic pathogen Aspergillus fumigatus is the most frequent cause of deadly airborne fungal infections in developed countries. In order to identify novel antifungal-drug targets, we investigated the genome of A. fumigatus for genes that are necessary for efficient fungal growth. An artificial A. fumigatus diploid strain with one copy of an engineered impala160 transposon from Fusarium oxysporum integrated into its genome was used to generate a library of diploid strains by random in vivo transposon mutagenesis. Among 2,386 heterozygous diploid strains screened by parasexual genetics, 1.2% had a copy of the transposable element integrated into a locus essential for A. fumigatus growth. Comparison of genomic sequences flanking impala160 in these mutants with that of the genome of A. fumigatus allowed the characterization of 20 previously uncharacterized A. fumigatus genes. Among these, homologues of genes essential for Saccharomyces cerevisiae growth have been identified, as well as genes that do not have homologues in other fungal species. These results confirm that heterologous transposition using the transposable element impala is a powerful tool for functional genomics in ascomycota, and they pave the way for defining the complete set of essential genes in A. fumigatus, the first step toward target-based development of new antifungal drugs.

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Analytical and Clinical Evaluation of the PathoNostics AsperGenius Assay for Detection of Invasive Aspergillosis and Resistance to Azole Antifungal Drugs Directly from Plasma Samples

Journal of Clinical Microbiology ◽

10.1128/jcm.00411-17 ◽

2017 ◽

Vol 55 (8) ◽

pp. 2356-2366 ◽

Cited By ~ 33

Author(s):

P. Lewis White ◽

Raquel B. Posso ◽

Rosemary A. Barnes

Keyword(s):

Clinical Study ◽

Invasive Aspergillosis ◽

Clinical Performance ◽

Fungal Infections ◽

Antifungal Drugs ◽

European Organization ◽

Content Type ◽

Enhanced Sensitivity ◽

Resistant Disease ◽

Single Positive

ABSTRACT With the proposal to include Aspergillus PCR in the revised European Organization for Research and Treatment of Cancer/Invasive Fungal Infections Cooperative Group and National Institute of Allergy and Infectious Diseases Mycoses Study Group (EORTC/MSG) definitions for fungal disease, commercially manufactured assays may be required to provide standardization and accessibility. The PathoNostics AsperGenius assay represents one such test that has the ability to detect a range of Aspergillus species as well as azole resistance in Aspergillus fumigatus . Its performance has been validated on bronchoalveolar lavage (BAL) fluid and serum specimens, but recent evidence suggests that testing of plasma may have enhanced sensitivity over that with serum. We decided to evaluate the analytical and clinical performances of the PathoNostics AsperGenius assay for testing of plasma. For the analytical evaluations, plasma was spiked with various concentrations of Aspergillus genomic DNA before extraction following international recommendations, using two automated platforms. For the clinical study, 211 samples from 10 proven/probable invasive aspergillosis (IA) and 2 possible IA cases and 27 controls were tested. The limits of detection for testing of DNA extracted using the bioMérieux EasyMag and Qiagen EZ1 extractors were 5 and 10 genomes/0.5-ml sample, respectively. In the clinical study, true positivity was significantly greater than false positivity ( P < 0.0001). The sensitivity and specificity obtained using a single positive result as significant were 80% and 77.8%, respectively. If multiple samples were required to be positive, specificity was increased to 100%, albeit sensitivity was reduced to 50%. The AsperGenius assay provided good clinical performance, but the predicted improvement of testing with plasma was not seen, possibly as a result of target degradation attributed to sample storage. Prospective testing is required to determine the clinical utility of this assay, particularly for the diagnosis of azole-resistant disease.

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