scholarly journals In VitroandIn VivoEvaluation of APX001A/APX001 and Other Gwt1 Inhibitors againstCryptococcus

2018 ◽  
Vol 62 (8) ◽  
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.

scholarly journals A Novel Actin Binding Drug with In Vivo Efficacy

2018 ◽  
Vol 63 (1) ◽  
Author(s):  
Akshaya Ravichandran ◽  
Mengxin Geng ◽  
Kenneth G. Hull ◽  
Jing Li ◽  
Daniel Romo ◽  
...  
Keyword(s):  
Fungal Infections ◽  
Apoptotic Cell ◽  
Affinity Purification ◽  
Treatment Options ◽  
Actin Dynamics ◽  
Actin Binding ◽  
Content Type ◽  
Actin Cables

ABSTRACT Occidiofungin is produced by the soil bacterium Burkolderia contaminans MS14 and is structurally similar or identical to the burkholdines, xylocandins, and cepacidines. This study identified the primary cellular target of occidiofungin, which was determined to be actin. The modification of occidiofungin with a functional alkyne group enabled affinity purification assays and localization studies in yeast. Occidiofungin has a subtle effect on actin dynamics that triggers apoptotic cell death. We demonstrate the highly specific localization of occidiofungin to cellular regions rich in actin in yeast and the binding of occidiofungin to purified actin in vitro. Furthermore, a disruption of actin-mediated cellular processes, such as endocytosis, nuclear segregation, and hyphal formation, was observed. All of these processes require the formation of stable actin cables, which are disrupted following the addition of a subinhibitory concentration of occidiofungin. We were also able to demonstrate the effectiveness of occidiofungin in treating a vulvovaginal yeast infection in a murine model. The results of this study are important for the development of an efficacious novel class of actin binding drugs that may fill the existing gap in treatment options for fungal infections or different types of cancer.

scholarly journals A Novel Polyaminocarboxylate Compound To Treat Murine Pulmonary Aspergillosis by Interfering with Zinc Metabolism

2018 ◽  
Vol 62 (6) ◽  
Author(s):  
Paris Laskaris ◽  
Rocío Vicentefranqueira ◽  
Olivier Helynck ◽  
Grégory Jouvion ◽  
José Antonio Calera ◽  
...  
Keyword(s):  
Fungal Infections ◽  
Treatment Options ◽  
Fungal Growth ◽  
Opportunistic Pathogen ◽  
Zinc Metabolism ◽  
Pulmonary Aspergillosis ◽  
Hyphal Length ◽  
Content Type

ABSTRACT Aspergillus fumigatus can cause pulmonary aspergillosis in immunocompromised patients and is associated with a high mortality rate due to a lack of reliable treatment options. This opportunistic pathogen requires zinc in order to grow and cause disease. Novel compounds that interfere with fungal zinc metabolism may therefore be of therapeutic interest. We screened chemical libraries containing 59,223 small molecules using a resazurin assay that compared their effects on an A. fumigatus wild-type strain grown under zinc-limiting conditions and on a zinc transporter knockout strain grown under zinc-replete conditions to identify compounds affecting zinc metabolism. After a first screen, 116 molecules were selected whose inhibitory effects on fungal growth were further tested by using luminescence assays and hyphal length measurements to confirm their activity, as well as by toxicity assays on HeLa cells and mice. Six compounds were selected following a rescreening, of which two were pyrazolones, two were porphyrins, and two were polyaminocarboxylates. All three groups showed good in vitro activity, but only one of the polyaminocarboxylates was able to significantly improve the survival of immunosuppressed mice suffering from pulmonary aspergillosis. This two-tier screening approach led us to the identification of a novel small molecule with in vivo fungicidal effects and low murine toxicity that may lead to the development of new treatment options for fungal infections by administration of this compound either as a monotherapy or as part of a combination therapy.

scholarly journals ZN148 Is a Modular Synthetic Metallo-β-Lactamase Inhibitor That Reverses Carbapenem Resistance in Gram-Negative Pathogens In Vivo

2020 ◽  
Vol 64 (6) ◽  
Author(s):  
Ørjan Samuelsen ◽  
Ove Alexander Høgmoen Åstrand ◽  
Christopher Fröhlich ◽  
Adam Heikal ◽  
Susann Skagseth ◽  
...  
Keyword(s):  
Active Site ◽  
Therapeutic Potential ◽  
Treatment Options ◽  
Carbapenem Resistance ◽  
Functional Space ◽  
Bactericidal Effect ◽  
Gram Negative ◽  
Content Type

ABSTRACT Carbapenem-resistant Gram-negative pathogens are a critical public health threat and there is an urgent need for new treatments. Carbapenemases (β-lactamases able to inactivate carbapenems) have been identified in both serine β-lactamase (SBL) and metallo-β-lactamase (MBL) families. The recent introduction of SBL carbapenemase inhibitors has provided alternative therapeutic options. Unfortunately, there are no approved inhibitors of MBL-mediated carbapenem-resistance and treatment options for infections caused by MBL-producing Gram-negatives are limited. Here, we present ZN148, a zinc-chelating MBL-inhibitor capable of restoring the bactericidal effect of meropenem and in vitro clinical susceptibility to carbapenems in >98% of a large international collection of MBL-producing clinical Enterobacterales strains (n = 234). Moreover, ZN148 was able to potentiate the effect of meropenem against NDM-1-producing Klebsiella pneumoniae in a murine neutropenic peritonitis model. ZN148 showed no inhibition of the human zinc-containing enzyme glyoxylase II at 500 μM, and no acute toxicity was observed in an in vivo mouse model with cumulative dosages up to 128 mg/kg. Biochemical analysis showed a time-dependent inhibition of MBLs by ZN148 and removal of zinc ions from the active site. Addition of exogenous zinc after ZN148 exposure only restored MBL activity by ∼30%, suggesting an irreversible mechanism of inhibition. Mass-spectrometry and molecular modeling indicated potential oxidation of the active site Cys221 residue. Overall, these results demonstrate the therapeutic potential of a ZN148-carbapenem combination against MBL-producing Gram-negative pathogens and that ZN148 is a highly promising MBL inhibitor that is capable of operating in a functional space not presently filled by any clinically approved compound.

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

2014 ◽  
Vol 59 (2) ◽  
pp. 1341-1343 ◽  
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.

scholarly journals Reversal of Azole Resistance inCandida albicansby Sulfa Antibacterial Drugs

2017 ◽  
Vol 62 (3) ◽  
Author(s):  
Hassan E. Eldesouky ◽  
Abdelrahman Mayhoub ◽  
Tony R. Hazbun ◽  
Mohamed N. Seleem
Keyword(s):  
Treatment Options ◽  
Antifungal Drugs ◽  
Infection Model ◽  
Azole Resistance ◽  
Global Public Health ◽  
Sulfa Drugs ◽  
Antibacterial Drugs ◽  
Content Type

ABSTRACTInvasive candidiasis presents an emerging global public health challenge due to the emergence of resistance to the frontline treatment options, such as fluconazole. Hence, the identification of other compounds capable of pairing with fluconazole and averting azole resistance would potentially prolong the clinical utility of this important group. In an effort to repurpose drugs in the field of antifungal drug discovery, we explored sulfa antibacterial drugs for the purpose of reversing azole resistance inCandida. In this study, we assembled and investigated a library of 21 sulfa antibacterial drugs for their ability to restore fluconazole sensitivity inCandida albicans. Surprisingly, the majority of assayed sulfa drugs (15 of 21) were found to exhibit synergistic relationships with fluconazole by checkerboard assay with fractional inhibitory concentration index (ΣFIC) values ranging from <0.0312 to 0.25. Remarkably, five sulfa drugs were able to reverse azole resistance in a clinically achievable range. The structure-activity relationships (SARs) of the amino benzene sulfonamide scaffold as antifungal agents were studied. We also identified the possible mechanism of the synergistic interaction of sulfa antibacterial drugs with azole antifungal drugs. Furthermore, the ability of sulfa antibacterial drugs to inhibitCandidabiofilm by 40%in vitrowas confirmed. In addition, the effects of sulfa-fluconazole combinations onCandidagrowth kinetics and efflux machinery were explored. Finally, using aCaenorhabditis elegansinfection model, we demonstrated that the sulfa-fluconazole combination does possess potent antifungal activityin vivo, reducingCandidain infected worms by ∼50% compared to the control.

scholarly journals The Fungal Cyp51-Specific Inhibitor VT-1598 DemonstratesIn VitroandIn VivoActivity againstCandida auris

2018 ◽  
Vol 63 (3) ◽  
Author(s):  
Nathan P. Wiederhold ◽  
Shawn R. Lockhart ◽  
Laura K. Najvar ◽  
Elizabeth L. Berkow ◽  
Rosie Jaramillo ◽  
...  
Keyword(s):  
Specific Inhibitor ◽  
Candida Auris ◽  
Once Daily ◽  
Content Type ◽  
Fungal Burden ◽  
Invasive Infections ◽  
Trough Concentrations ◽  
Dose Dependent

ABSTRACTCandida aurisis an emerging pathogen associated with significant mortality and often multidrug resistance. VT-1598, a tetrazole-based fungal CYP51-specific inhibitor, was evaluatedin vitroandin vivoagainstC. auris. Susceptibility testing was performed against 100 clinical isolates ofC. aurisby broth microdilution. Neutropenic mice were infected intravenously withC. auris, and treatment began 24 h postinoculation with a vehicle control, oral VT-1598 (5, 15, and 50 mg/kg of body weight once daily), oral fluconazole (20 mg/kg once daily), or intraperitoneal caspofungin (10 mg/kg once daily), which continued for 7 days. Fungal burden was assessed in the kidneys and brains on day 8 in the fungal burden arm and on the days the mice succumbed to infection or on day 21 in the survival arm. VT-1598 plasma trough concentrations were also assessed on day 8. VT-1598 demonstratedin vitroactivity againstC. auris, with a mode MIC of 0.25 μg/ml and MICs ranging from 0.03 to 8 μg/ml. Treatment with VT-1598 resulted in significant and dose-dependent improvements in survival (median survival, 15 and >21 days for VT-1598 at 15 and 50 mg/kg, respectively) and reductions in kidney and brain fungal burden (reductions of 1.88 to 3.61 log10CFU/g) compared to the control (5 days). The reductions in fungal burden correlated with plasma trough concentrations. Treatment with caspofungin, but not fluconazole, also resulted in significant improvements in survival and reductions in fungal burden compared to those with the control. These results suggest that VT-1598 may be a future option for the treatment of invasive infections caused byC. auris.

scholarly journals The Novel Arylamidine T-2307 Demonstrates In Vitro and In Vivo Activity against Candida auris

2019 ◽  
Vol 64 (3) ◽  
Author(s):  
Nathan P. Wiederhold ◽  
Laura K. Najvar ◽  
Rosie Jaramillo ◽  
Marcos Olivo ◽  
Hoja Patterson ◽  
...  
Keyword(s):  
The Novel ◽  
Candida Auris ◽  
Once Daily ◽  
Content Type ◽  
Fungal Burden

ABSTRACT The in vitro and in vivo activity of the arylamidine T-2307 against Candida auris was evaluated. T-2307 demonstrated in vitro activity (MIC ranges ≤ 0.008 to 0.015 μg/ml at 50% inhibition; 0.125 to >4 μg/ml at 100% inhibition). Treatment with T-2307 (3 mg/kg subcutaneous [SC] once daily) also significantly improved survival (70% at 21 days postinfection) and reduced kidney fungal burden (5.06 log10 CFU/g) compared to control (0% survival and 7.09 log10 CFU/g) (P < 0.01).

scholarly journals New Triazole NT-a9 Has Potent Antifungal Efficacy against Cryptococcus neoformans In Vitro and In Vivo

2019 ◽  
Vol 64 (2) ◽  
Author(s):  
Ren-Yi Lu ◽  
Ting-Jun-Hong Ni ◽  
Jing Wu ◽  
Lan Yan ◽  
Quan-Zhen Lv ◽  
...  
Keyword(s):  
Cryptococcus Neoformans ◽  
Amphotericin B ◽  
Pathogenic Fungi ◽  
Control Group ◽  
Survival Times ◽  
Content Type ◽  
Fungal Burden ◽  
Wide Range

ABSTRACT In the past decades, the incidence of cryptococcosis has increased dramatically, which poses a new threat to human health. However, only a few drugs are available for the treatment of cryptococcosis. Here, we described a leading compound, NT-a9, an analogue of isavuconazole, that showed strong antifungal activities in vitro and in vivo. NT-a9 showed a wide range of activities against several pathogenic fungi in vitro, including Cryptococcus neoformans, Cryptococcus gattii, Candida albicans, Candida krusei, Candida tropicalis, Candida glabrata, and Candida parapsilosis, with MICs ranging from 0.002 to 1 μg/ml. In particular, NT-a9 exhibited excellent efficacy against C. neoformans, with a MIC as low as 0.002 μg/ml. NT-a9 treatment resulted in changes in the sterol contents in C. neoformans, similarly to fluconazole. In addition, NT-a9 possessed relatively low cytotoxicity and a high selectivity index. The in vivo efficacy of NT-a9 was assessed using a murine disseminated-cryptococcosis model. Mice were infected intravenously with 1.8 × 106 CFU of C. neoformans strain H99. In the survival study, NT-a9 significantly prolonged the survival times of mice compared with the survival times of the control group or the isavuconazole-, fluconazole-, or amphotericin B-treated groups. Of note, 4 and 8 mg/kg of body weight of NT-a9 rescued all the mice, with a survival rate of 100%. In the fungal-burden study, NT-a9 also significantly reduced the fungal burdens in brains and lungs, while fluconazole and amphotericin B only reduced the fungal burden in lungs. Taken together, these data suggested that NT-a9 is a promising antifungal candidate for the treatment of cryptococcosis infection.

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

mSphere ◽  
2021 ◽  
Author(s):  
Rohan S. Wakade ◽  
Manning Huang ◽  
Aaron P. Mitchell ◽  
Melanie Wellington ◽  
Damian J. Krysan
Keyword(s):  
Candida Albicans ◽  
Fungal Infections ◽  
Deletion Mutants ◽  
Filamentous Form ◽  
Content Type ◽  
Yeast Form ◽  
Common Causes ◽  
Do So

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.

scholarly journals The Mouse Inhalation Model ofCryptococcus neoformansInfection Recapitulates Strain Virulence in Humans and Shows that Closely Related Strains Can Possess Differential Virulence

2019 ◽  
Vol 87 (5) ◽  
Author(s):  
Liliane Mukaremera ◽  
Tami R. McDonald ◽  
Judith N. Nielsen ◽  
Christopher J. Molenaar ◽  
Andrew Akampurira ◽  
...  
Keyword(s):  
Survival Time ◽  
Cryptococcal Meningitis ◽  
Strong Association ◽  
Human Infection ◽  
Sequence Type ◽  
Disease Outcome ◽  
Content Type ◽  
Fungal Burden

ABSTRACTCryptococcal meningitis (CM) causes high rates of HIV-related mortality, yet theCryptococcusfactors influencing patient outcome are not well understood. Pathogen-specific traits, such as the strain genotype and degree of antigen shedding, are associated with the clinical outcome, but the underlying biology remains elusive. In this study, we examined factors determining disease outcome in HIV-infected cryptococcal meningitis patients infected withCryptococcus neoformansstrains with the same multilocus sequence type (MLST). Both patient mortality and survival were observed during infections with the same sequence type. Disease outcome was not associated with the patient CD4 count. Patient mortality was associated with higher cryptococcal antigen levels, the cerebrospinal fluid (CSF) fungal burden by quantitative culture, and low CSF fungal clearance. The virulence of a subset of clinical strains with the same sequence type was analyzed using a mouse inhalation model of cryptococcosis. We showed a strong association between human and mouse mortality rates, demonstrating that the mouse inhalation model recapitulates human infection. Similar to human infection, the ability to multiplyin vivo, demonstrated by a high fungal burden in lung and brain tissues, was associated with mouse mortality. Mouse survival time was not associated with singleC. neoformansvirulence factorsin vitroorin vivo; rather, a trend in survival time correlated with a suite of traits. These observations show that MLST-derived genotype similarities betweenC. neoformansstrains do not necessarily translate into similar virulence either in the mouse model or in human patients. In addition, our results show thatin vitroassays do not fully reproducein vivoconditions that influenceC. neoformansvirulence.

Sign in / Sign up

Export Citation Format

Share Document