scholarly journals Targeted Action and Molecular Interactions of Sarcin and Thionin With Aspergillosis Causing Aspergillus fumigatus

2021 ◽  
Author(s):  
Ramya Ravindhiran ◽  
Ramya Krishnamurthy ◽  
Karthiga Sivarajan ◽  
JothiNayaki Sekar ◽  
Kumarappan Chidambaram ◽  
...  
Keyword(s):  
Aspergillus Fumigatus ◽  
Fungal Infections ◽  
Sem Analysis ◽  
Antifungal Drugs ◽  
Bioactive Metabolites ◽  
Antifungal Compounds ◽  
Aspergillus Giganteus ◽  
Virulence Proteins ◽  
Antagonistic Potential ◽  
Related Proteins

Fungal infections are more predominant in agricultural and clinical fields. Aspergillosis caused by Aspergillus fumigatus leads to respiratory failure in patients along with various illnesses. Due to the limitation of antifungal therapy and antifungal drugs, there is an emergence to develop efficient antifungal compounds from natural sources to cure and prevent fungal infections. The present study deals with the investigation of the mechanism of active compounds from our candidate agonist Aspergillus giganteus for aspergillosis. The integrity of treated Aspergillus fumigatus cell membrane and nuclear membrane was analyzed by determining the release of cellular materials. The antagonistic potential of antifungal compounds on the pathogen was confirmed by SEM analysis. The effective concentration of antifungal compounds (AFCs) was found to be 250µg/ml. The GC-MS profiling has revealed the bioactive metabolites responsible for the antagonistic nature of Aspergillus giganteus. The bioavailability and toxicological properties of pathogenesis related proteins have proved the efficiency of pharmacokinetic properties of selected compounds. Interaction of sarcin, thionin, chitinase and its derivatives from Aspergillus giganteus with the virulence proteins of UDP-N-acetylglucosamine pyrophosphorylase, N-myristoyl transferase and Chitinase have proved the druggable nature of the antifungal compounds.

scholarly journals A Unique Dual-Readout High-Throughput Screening Assay To Identify Antifungal Compounds with Aspergillus fumigatus

mSphere ◽  
2021 ◽  
Author(s):  
Sarah R. Beattie ◽  
Damian J. Krysan
Keyword(s):  
Aspergillus Fumigatus ◽  
High Throughput ◽  
High Throughput Screening ◽  
Fungal Infections ◽  
Mortality Rates ◽  
Antifungal Drugs ◽  
Antifungal Compounds ◽  
Screening Assay ◽  
High Throughput Screening Assay

Fungal infections caused by molds have the highest mortality rates of human fungal infections. These devastating infections are hard to treat and available antifungal drugs are often not effective.

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

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.

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

2003 ◽  
Vol 2 (2) ◽  
pp. 247-255 ◽  
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.

scholarly journals Crystal Structure of the New Investigational Drug Candidate VT-1598 in Complex with Aspergillus fumigatus Sterol 14α-Demethylase Provides Insights into Its Broad-Spectrum Antifungal Activity

2017 ◽  
Vol 61 (7) ◽  
Author(s):  
Tatiana Y. Hargrove ◽  
Edward P. Garvey ◽  
William J. Hoekstra ◽  
Christopher M. Yates ◽  
Zdzislaw Wawrzak ◽  
...  
Keyword(s):  
Antifungal Activity ◽  
Aspergillus Fumigatus ◽  
Broad Spectrum ◽  
Fungal Infections ◽  
Enzymatic Reaction ◽  
Heme Iron ◽  
Antifungal Drugs ◽  
Drug Candidate ◽  
Investigational Drug ◽  
Content Type

ABSTRACT Within the past few decades, the incidence and complexity of human fungal infections have increased, and therefore, the need for safer and more efficient, broad-spectrum antifungal agents is high. In the study described here, we characterized the new tetrazole-based drug candidate VT-1598 as an inhibitor of sterol 14α-demethylase (CYP51B) from the filamentous fungus Aspergillus fumigatus. VT-1598 displayed a high affinity of binding to the enzyme in solution (dissociation constant, 13 ± 1 nM) and in the reconstituted enzymatic reaction was revealed to have an inhibitory potency stronger than the potencies of all other simultaneously tested antifungal drugs, including fluconazole, voriconazole, ketoconazole, and posaconazole. The X-ray structure of the VT-1598/A. fumigatus CYP51 complex was determined and depicts the distinctive binding mode of the inhibitor in the enzyme active site, suggesting the molecular basis of the improved drug potency and broad-spectrum antifungal activity. These data show the formation of an optimized hydrogen bond between the phenoxymethyl oxygen of VT-1598 and the imidazole ring nitrogen of His374, the CYP51 residue that is highly conserved across fungal pathogens and fungus specific. Comparative structural analysis of A. fumigatus CYP51/voriconazole and Candida albicans CYP51/VT-1161 complexes supports the role of H bonding in fungal CYP51/inhibitor complexes and emphasizes the importance of an optimal distance between this interaction and the inhibitor-heme iron interaction. Cellular experiments using two A. fumigatus strains (strains 32820 and 1022) displayed a direct correlation between the effects of the drugs on CYP51B activity and fungal growth inhibition, indicating the noteworthy anti-A. fumigatus potency of VT-1598 and confirming its promise as a broad-spectrum antifungal agent.

scholarly journals Discovery of a Small-Molecule Inhibitor of β-1,6-Glucan Synthesis

2008 ◽  
Vol 53 (2) ◽  
pp. 670-677 ◽  
Author(s):  
Akihiro Kitamura ◽  
Kazuhiko Someya ◽  
Masato Hata ◽  
Ryohei Nakajima ◽  
Makoto Takemura
Keyword(s):  
Mammalian Cells ◽  
Fungal Infections ◽  
Specific Inhibitor ◽  
Resistant Mutant ◽  
Antifungal Drugs ◽  
Antifungal Compounds ◽  
Primary Target ◽  
Molecule Inhibitor ◽  
Glucan Synthesis ◽  
Lines Of Evidence

ABSTRACT It is possible that antifungal drugs with novel modes of action will provide favorable options to treat fungal infections. In the course of our screening for antifungal compounds acting on the cell wall, a pyridobenzimidazole derivative with unique activities, named D75-4590, was discovered. During treatment of Saccharomyces cerevisiae with D75-4590, (i) incorporation of [14C]glucose into the β-1,6-glucan component was selectively reduced, (ii) proteins released from the cell had lost the β-1,6-glucan moiety, and (iii) cells tended to clump, resulting in impaired cell growth. Genetic analysis of a D75-4590-resistant mutant of S. cerevisiae indicated that its primary target was Kre6p, which is considered to be one of the β-1,6-glucan synthases. These results strongly suggest that D75-4590 is a specific inhibitor of β-1,6-glucan synthesis. D75-4590 showed potent activities against various Candida species. It inhibited hyphal elongation of C. albicans as well. KRE6 is conserved in various fungi, but no homologue has been found in mammalian cells. These lines of evidence indicate that D75-4590 is a promising lead compound for novel antifungal drugs. To our knowledge, this is the first report of a β-1,6-glucan inhibitor.

scholarly journals Intimate genetic relationships and fungicide resistance in multiple strains of human pathogenic fungus Aspergillus fumigatus isolated from a plant bulb

2021 ◽  
Author(s):  
Hiroki Takahashi ◽  
Sayoko Oiki ◽  
Yoko Kusuya ◽  
Syun-ichi Urayama ◽  
Daisuke Hagiwara
Keyword(s):  
Aspergillus Fumigatus ◽  
Genetic Recombination ◽  
Fungal Infections ◽  
Genetic Relationships ◽  
Pathogenic Fungus ◽  
Antifungal Drugs ◽  
Environmental Niche ◽  
Typing Method ◽  
Tulip Bulb ◽  
Resistant Strains

Fungal infections are increasingly dangerous because of environmentally-dispersed resistance to antifungal drugs. Azoles are commonly used antifungal drugs, but they are also used as fungicides in agriculture, which may enable enrichment of azole-resistant strains of the human pathogen Aspergillus fumigatus in the environment. Understanding of environmental dissemination and enrichment of genetic variation associated with azole resistance in A. fumigatus is required to suppress resistant strains. Here, we focused on eight strains of azole-resistant A. fumigatus isolated from a single tulip bulb for sale in Japan. This set includes strains with TR34/L98H/T289A/I364V/G448S and TR46/Y121F/T289A/S363P/I364V/G448S mutations in the cyp51A gene, which showed higher tolerance to several azoles than strains harboring TR46/Y121F/T289A mutation. The strains were typed by microsatellite typing, single nucleotide polymorphism profiles, and mitochondrial and nuclear genome analyses. The strains grouped differently using each typing method, suggesting historical genetic recombination among the strains. Our data also revealed that some strains isolated from the tulip bulb showed tolerance to other classes of fungicide, such as QoI and carbendazim, followed by related amino acid alterations in the target proteins. Considering spatial-temporal factors, plant bulbs are an excellent environmental niche for fungal strains to encounter partners, and to obtain and spread resistance-associated mutations.

In Silico Identification of Antifungal Compounds as Mutant DHFRase Inhibitors: Structure-Based Approach, Molecular Dynamics Simulation and Structural Integrity Analysis

2021 ◽  
Vol 20 (06) ◽  
pp. 589-602
Author(s):  
Trambak Basak ◽  
Virendra Nath ◽  
Vipin Kumar ◽  
Amit Kumar Goyal
Keyword(s):  
Root Mean Square ◽  
Md Simulation ◽  
Structural Integrity ◽  
Fungal Infections ◽  
Antifungal Drugs ◽  
Dynamics Simulation ◽  
Antifungal Compounds ◽  
Mean Square ◽  
Ligand Complex ◽  
Energy Prediction

Fungal infection of invasive nature is an alarming threat globally and a leading cause of human morbidity and mortality as they are opportunistic in nature. Rising resistance to current clinically approved marketed products for fungal infections is a major concern for humans. Dihydrofolate Reductase (DHFRase) is an essential enzyme in folate metabolic pathway responsible for DNA synthesis and is ubiquitous to all organisms, and also acts as a key target for developing antifungal drugs. In this study, potential mutant DHFRase inhibitors were screened with the help of hierarchical mode of docking of virtual library of antifungal compounds and molecular dynamic (MD) simulation. The identification of best hits was done by using the docking, binding energy prediction and further, which was supported by their predicted pharmacokinetics. MD simulation of the human DHFRase enzyme with the reference lead compound i.e. PY957 and most promising hit found i.e. ChemDiv-C390-0455 and to validate the stability of enzyme-ligand complex in best 07 retrieved hit as a potential mutant DHFRase inhibitor. The key residues Glh30, Phe34, Phe64, Phe31 of the binding pocket acknowledged as essential were found to be matching with the key interactions of the selected hit. Computed root mean square deviation (RMSD) and root mean square fluctuation (RMSF) in MD simulation of complex of DHFRase enzyme with PY957 and ChemDiv-C390-0455 were read less than 2.25[Formula: see text]Å during 100 nanoseconds simulation for both complex.

scholarly journals Antifungal Drug Development: Targeting the Fungal Sphingolipid Pathway

2020 ◽  
Vol 6 (3) ◽  
pp. 142
Author(s):  
Kyle McEvoy ◽  
Tyler G. Normile ◽  
Maurizio Del Poeta
Keyword(s):  
Drug Resistance ◽  
Drug Development ◽  
Mechanism Of Action ◽  
Fungal Infections ◽  
Antifungal Drugs ◽  
Antifungal Drug ◽  
Antifungal Compounds ◽  
Metabolizing Enzymes ◽  
Progressive Development

Fungal infections are becoming more prevalent and problematic due to the continual rise of immune deficient patients as well as the progressive development of drug resistance towards currently available antifungal drugs. There has been a significant increase in the development of antifungal compounds with a similar mechanism of action of current drugs. In contrast, there has been very little progress in developing compounds inhibiting totally new fungal targets or/and fungal pathways. This review focuses on novel compounds recently discovered to target the fungal sphingolipids and their metabolizing enzymes.

scholarly journals Novel Hit Compounds as Putative Antifungals: The Case of Aspergillus fumigatus

Molecules ◽  
2019 ◽  
Vol 24 (21) ◽  
pp. 3853 ◽  
Author(s):  
Eftichia Kritsi ◽  
Minos-Timotheos Matsoukas ◽  
Constantinos Potamitis ◽  
Anastasia Detsi ◽  
Marija Ivanov ◽  
...  
Keyword(s):  
Antifungal Activity ◽  
Aspergillus Fumigatus ◽  
Fungal Pathogens ◽  
Fungal Infections ◽  
Pharmacophore Model ◽  
Antifungal Drugs ◽  
In Vitro Assays ◽  
Minimum Fungicidal Concentration ◽  
Dynamics Simulations

The prevalence of invasive fungal infections has been dramatically increased as the size of the immunocompromised population worldwide has grown. Aspergillus fumigatus is characterized as one of the most widespread and ubiquitous fungal pathogens. Among antifungal drugs, azoles have been the most widely used category for the treatment of fungal infections. However, increasingly, azole-resistant strains constitute a major problem to be faced. Towards this direction, our study focused on the identification of compounds bearing novel structural motifs which may evolve as a new class of antifungals. To fulfil this scope, a combination of in silico techniques and in vitro assays were implemented. Specifically, a ligand-based pharmacophore model was created and served as a 3D search query to screen the ZINC chemical database. Additionally, molecular docking and molecular dynamics simulations were used to improve the reliability and accuracy of virtual screening results. In total, eight compounds, bearing completely different chemical scaffolds from the commercially available azoles, were proposed and their antifungal activity was evaluated using in vitro assays. Results indicated that all tested compounds exhibit antifungal activity, especially compounds 1, 2, and 4, which presented the most promising minimum inhibitory concentration (MIC) and minimum fungicidal concentration (MFC) values and, therefore, could be subjected to further hit to lead optimization.

scholarly journals Aspergillus fumigatus Trehalose-Regulatory Subunit Homolog Moonlights To Mediate Cell Wall Homeostasis through Modulation of Chitin Synthase Activity

mBio ◽  
2017 ◽  
Vol 8 (2) ◽  
Author(s):  
Arsa Thammahong ◽  
Alayna K. Caffrey-Card ◽  
Sourabh Dhingra ◽  
Joshua J. Obar ◽  
Robert A. Cramer
Keyword(s):  
Cell Wall ◽  
Aspergillus Fumigatus ◽  
Fungal Infections ◽  
Hiv Infections ◽  
Pathogenic Fungi ◽  
Antifungal Drugs ◽  
Chitin Synthase ◽  
Wall Structure ◽  
Biosynthesis Pathway ◽  
Trehalose Biosynthesis

ABSTRACT Trehalose biosynthesis is found in fungi but not humans. Proteins involved in trehalose biosynthesis are essential for fungal pathogen virulence in humans and plants through multiple mechanisms. Loss of canonical trehalose biosynthesis genes in the human pathogen Aspergillus fumigatus significantly alters cell wall structure and integrity, though the mechanistic link between these virulence-associated pathways remains enigmatic. Here we characterize genes, called tslA and tslB, which encode proteins that contain domains similar to those corresponding to trehalose-6-phosphate phosphatase but lack critical catalytic residues for phosphatase activity. Loss of tslA reduces trehalose content in both conidia and mycelia, impairs cell wall integrity, and significantly alters cell wall structure. To gain mechanistic insights into the role that TslA plays in cell wall homeostasis, immunoprecipitation assays coupled with liquid chromatography-tandem mass spectrometry (LC-MS/MS) were used to reveal a direct interaction between TslA and CsmA, a type V chitin synthase enzyme. TslA regulates not only chitin synthase activity but also CsmA sub-cellular localization. Loss of TslA impacts the immunopathogenesis of murine invasive pulmonary aspergillosis through altering cytokine production and immune cell recruitment. In conclusion, our data provide a novel model whereby proteins in the trehalose pathway play a direct role in fungal cell wall homeostasis and consequently impact fungus-host interactions. IMPORTANCE Human fungal infections are increasing globally due to HIV infections and increased use of immunosuppressive therapies for many diseases. Therefore, new antifungal drugs with reduced side effects and increased efficacy are needed to improve treatment outcomes. Trehalose biosynthesis exists in pathogenic fungi and is absent in humans. Components of the trehalose biosynthesis pathway are important for the virulence of human-pathogenic fungi, including Aspergillus fumigatus. Consequently, it has been proposed that components of this pathway are potential targets for antifungal drug development. However, how trehalose biosynthesis influences the fungus-host interaction remains enigmatic. One phenotype associated with fungal trehalose biosynthesis mutants that remains enigmatic is cell wall perturbation. Here we discovered a novel moonlighting role for a regulatory-like subunit of the trehalose biosynthesis pathway in A. fumigatus that regulates cell wall homeostasis through modulation of chitin synthase localization and activity. As the cell wall is a current and promising therapeutic target for fungal infections, understanding the role of trehalose biosynthesis in cell wall homeostasis and virulence is expected to help define new therapeutic opportunities. IMPORTANCE Human fungal infections are increasing globally due to HIV infections and increased use of immunosuppressive therapies for many diseases. Therefore, new antifungal drugs with reduced side effects and increased efficacy are needed to improve treatment outcomes. Trehalose biosynthesis exists in pathogenic fungi and is absent in humans. Components of the trehalose biosynthesis pathway are important for the virulence of human-pathogenic fungi, including Aspergillus fumigatus. Consequently, it has been proposed that components of this pathway are potential targets for antifungal drug development. However, how trehalose biosynthesis influences the fungus-host interaction remains enigmatic. One phenotype associated with fungal trehalose biosynthesis mutants that remains enigmatic is cell wall perturbation. Here we discovered a novel moonlighting role for a regulatory-like subunit of the trehalose biosynthesis pathway in A. fumigatus that regulates cell wall homeostasis through modulation of chitin synthase localization and activity. As the cell wall is a current and promising therapeutic target for fungal infections, understanding the role of trehalose biosynthesis in cell wall homeostasis and virulence is expected to help define new therapeutic opportunities.

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