scholarly journals Efficient Clearance of Aspergillus fumigatus in Murine Lungs by an Ultrashort Antimicrobial Lipopeptide, Palmitoyl-Lys-Ala-dAla-Lys

2008 ◽  
Vol 52 (9) ◽  
pp. 3118-3126 ◽  
Author(s):  
Alexandra Vallon-Eberhard ◽  
Arik Makovitzki ◽  
Anne Beauvais ◽  
Jean-Paul Latgé ◽  
Steffen Jung ◽  
...  
Keyword(s):  
Invasive Aspergillosis ◽  
Aspergillus Fumigatus ◽  
Microscopic Analysis ◽  
Current Standard ◽  
New Family ◽  
Therapeutic Properties ◽  
Survival Assay ◽  
Opportunistic Fungal Pathogen

ABSTRACT Aspergillus fumigatus is an opportunistic fungal pathogen responsible for invasive aspergillosis in immunocompromised individuals. The inefficiency of antifungal agents and high mortality rate resulting from invasive aspergillosis remain major clinical concerns. Recently, we reported on a new family of ultrashort cationic lipopeptides active in vitro against fungi. Mode of action studies supported a membranolytic or a detergent-like effect. Here, we screened several lipopeptides in vitro for their anti-A. fumigatus activity. To investigate the therapeutic properties of the selected peptides in vivo, we challenged immunosuppressed C57BL/6 wild-type mice intranasally with DsRed-labeled A. fumigatus conidia and subsequently treated the animals locally with the lipopeptides. Confocal microscopic analysis revealed the degradation of DsRed-labeled hyphal forms and residual conidia in the lungs of the mice. The most efficient peptide was tested further using a survival assay and was found to significantly prolong the life of the treated animals, whereas no mice survived with the current standard antifungal treatment with amphotericin B. Moreover, as opposed to the drug-treated lungs, the peptide-treated lungs did not display any toxicity of the peptide. Our results highlight the potential of this family of lipopeptides for the treatment of pulmonary invasive aspergillosis.

scholarly journals Aspergillus fumigatus inhibits angiogenesis through the production of gliotoxin and other secondary metabolites

Blood ◽  
2009 ◽  
Vol 114 (26) ◽  
pp. 5393-5399 ◽  
Author(s):  
Ronen Ben-Ami ◽  
Russell E. Lewis ◽  
Konstantinos Leventakos ◽  
Dimitrios P. Kontoyiannis
Keyword(s):  
Invasive Aspergillosis ◽  
Aspergillus Fumigatus ◽  
Capillary Tube ◽  
Umbilical Vein ◽  
Tube Formation ◽  
Dependent Manner ◽  
Antiangiogenic Effect ◽  
Umbilical Vein Endothelial Cells

AbstractIn susceptible hosts, angioinvasion by Aspergillus fumigatus triggers thrombosis, hypoxia, and proinflammatory cytokine release, all of which are stimuli for angiogenesis. We sought to determine whether A fumigatus directly modulates angiogenesis. A fumigatus culture filtrates profoundly inhibited the differentiation, migration, and capillary tube formation of human umbilical vein endothelial cells in vitro. To measure angiogenesis at the site of infection, we devised an in vivo Matrigel assay in cyclophosphamide-treated BALB/c mice with cutaneous invasive aspergillosis. Angiogenesis was significantly suppressed in Matrigel plugs implanted in A fumigatus–infected mice compared with plugs from uninfected control mice. The antiangiogenic effect of A fumigatus was completely abolished by deletion of the global regulator of secondary metabolism, laeA, and to a lesser extent by deletion of gliP, which controls gliotoxin production. Moreover, pure gliotoxin potently inhibited angiogenesis in vitro in a dose-dependent manner. Finally, overexpression of multiple angiogenesis mediator–encoding genes was observed in the lungs of cortisone-treated mice during early invasive aspergillosis, whereas gene expression returned rapidly to baseline levels in cyclophosphamide/cortisone-treated mice. Taken together, these results indicate that suppression of angiogenesis by A fumigatus both in vitro and in a neutropenic mouse model is mediated through secondary metabolite production.

scholarly journals Ficolins Promote Fungal Clearance in vivo and Modulate the Inflammatory Cytokine Response in Host Defense against Aspergillus fumigatus

2016 ◽  
Vol 8 (6) ◽  
pp. 579-588 ◽  
Author(s):  
Ninette Genster ◽  
Elisabeth Præstekjær Cramer ◽  
Anne Rosbjerg ◽  
Katrine Pilely ◽  
Jack Bernard Cowland ◽  
...  
Keyword(s):  
Aspergillus Fumigatus ◽  
Host Defense ◽  
Knockout Mice ◽  
Fungal Infections ◽  
Inflammatory Cells ◽  
Lectin Pathway ◽  
Wild Type ◽  
Opportunistic Fungal Pathogen

Aspergillus fumigatus is an opportunistic fungal pathogen that causes severe invasive infections in immunocompromised patients. Innate immunity plays a major role in protection against A. fumigatus. The ficolins are a family of soluble pattern recognition receptors that are capable of activating the lectin pathway of complement. Previous in vitro studies reported that ficolins bind to A. fumigatus, but their part in host defense against fungal infections in vivo is unknown. In this study, we used ficolin-deficient mice to investigate the role of ficolins during lung infection with A. fumigatus. Ficolin knockout mice showed significantly higher fungal loads in the lungs 24 h postinfection compared to wild-type mice. The delayed clearance of A. fumigatus in ficolin knockout mice could not be attributed to a compromised recruitment of inflammatory cells. However, it was revealed that ficolin knockout mice exhibited a decreased production of proinflammatory cytokines in the lungs compared to wild-type mice following A. fumigatus infection. The impaired clearance and cytokine production in ficolin knockout mice was independent of complement, as shown by equivalent levels of A. fumigatus-mediated complement activation in ficolin knockout mice and wild-type mice. In conclusion, this study demonstrates that ficolins are important in initial innate host defense against A. fumigatus infections in vivo.

scholarly journals Effect of Quarum Sensing Molecules on Aspergillus fumigatus

2019 ◽  
Vol 17 (4) ◽  
pp. 348-358
Author(s):  
Thanwa WONGSUK ◽  
Passanesh SUKPHOPETCH
Keyword(s):  
Aspergillus Fumigatus ◽  
Biofilm Formation ◽  
Cell Damage ◽  
A549 Cells ◽  
Alveolar Epithelial Cells ◽  
Cytotoxic Activities ◽  
Solid Media ◽  
Opportunistic Fungal Pathogen

Aspergillus fumigatus is an opportunistic fungal pathogen to which immunocompromised patients are especially susceptible. A. fumigatus can form biofilms both in vitro and in vivo. Quorum sensing molecules (QSMs) have activity against some fungi. This study aimed to determine the activity of the QSMs farnesol, tyrosol, phenylethanol and tryptophol against the growth A. fumigatus on solid media, and against its ability to form biofilms. The activity of each QSM against planktonic A. fumigatus growth was assessed using the CLSI M38-A2 broth microdilution assay, while QSM inhibition of A. fumigatus’s biofilm formation was measured in crystal violet, and 2, 3-bis (2-methoxy-4-nitro-5-sulfo-phenyl)-2H-tetrazolium-5-caboxanilide (XTT) assays. The QSMs reduced the colony diameter of the studied strains in a QSM-dependent pattern. Tryptophol showed the best effect and tyrosol showed the poorest effect. The minimum inhibitory concentrations (MICs) for farnesol, tyrosol, phenylethanol and tryptophol tested against A. fumigatus were > 32, > 32, 16 and 8 mM, respectively. The effective concentration each QSM required to inhibit A. fumigatus biofilm formation were higher than the planktonic MICs. In this study, the performance of QSMs against A. fumigatus ranked from best to worst as follows: tryptophol, phenylethanol, farnesol and tyrosol. Because of phenylethanol and tryptophol showed the strongest effect to the growth and biofilm formation of A. fumigatus. Therefore, the cytotoxic activities of phenylethanol and tryptophol in A549 cells (lung alveolar epithelial cells) were determined. However, phenylethanol and tryptophol induced A549 cell damage (at MIC level), as demonstrated by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium (MTT) and lactate dehydrogenase (LDH) assays.

scholarly journals Determining Aspergillus fumigatus transcription factor expression and function during invasion of the mammalian lung

2020 ◽  
Author(s):  
Hong Liu ◽  
Wenjie Xu ◽  
Vincent M. Bruno ◽  
Quynh T. Phan ◽  
Norma V. Solis ◽  
...  
Keyword(s):  
Transcription Factor ◽  
Transcription Factors ◽  
Secondary Metabolites ◽  
Invasive Aspergillosis ◽  
Aspergillus Fumigatus ◽  
Transcriptional Profiling ◽  
Transcriptional Response ◽  
Transcription Factor Genes

AbstractTo gain a better understanding of the transcriptional response of Aspergillus fumigatus during invasive pulmonary infection, we used a NanoString nCounter to assess the transcript levels of 467 A. fumigatus genes during growth in the lungs of immunosuppressed mice. These genes included ones known to respond to diverse environmental conditions and those encoding most transcription factors in the A. fumigatus genome. We found that invasive growth in vivo induces a unique transcriptional profile as the organism responds to nutrient limitation and attack by host phagocytes. This in vivo transcriptional response is largely mimicked by in vitro growth in Aspergillus minimal medium that is deficient in nitrogen, iron, and/or zinc. From the transcriptional profiling data, we selected 9 transcription factor genes that were either highly expressed or strongly up-regulated during in vivo growth. Deletion mutants were constructed for each of these genes and assessed for virulence in mice. Two transcription factor genes were found to be required for maximal virulence. One was rlmA, which governs the ability of the organism to proliferate in the lung. The other was ace1, which regulates of the expression of multiple secondary metabolite gene clusters and mycotoxin genes independently of laeA. Using deletion and overexpression mutants, we determined that the attenuated virulence of the Δace1 mutant is due to decreased expression aspf1, which specifies a ribotoxin, but is not mediated by reduced expression of the fumigaclavine gene cluster or the fumagillin-pseruotin supercluster. Thus, in vivo transcriptional profiling focused on transcription factors genes provides a facile approach to identifying novel virulence regulators.Author summaryAlthough A. fumigatus causes the majority of cases of invasive aspergillosis, the function of most of the genes in its genome remains unknown. To identify genes encoding transcription factors that may be important for virulence, we used a NanoString nCounter to measure the mRNA levels of A. fumigatus transcription factor genes in the lungs of mice with invasive aspergillosis. The transcriptional profiling data indicate that the organism is exposed to nutrient limitation and stress during growth in the lungs, and that it responds by up-regulating genes that encode mycotoxins and secondary metabolites. In vitro, this response was most closely mimicked by growth in medium that was deficient in nitrogen, iron and/or zinc. Using the transcriptional profiling data, we identified two transcription factors that govern A. fumigatus virulence. These were RlmA, which is governs proliferation in the lung and Ace1, which controls the production of mycotoxins and secondary metabolites.

scholarly journals In Vitro Activities at pH 5.0 and pH 7.0 and In Vivo Efficacy of Flucytosine against Aspergillus fumigatus

2008 ◽  
Vol 52 (12) ◽  
pp. 4483-4485 ◽  
Author(s):  
Paul E. Verweij ◽  
Debbie T. A. Te Dorsthorst ◽  
Willem H. P. Janssen ◽  
Jacques F. G. M. Meis ◽  
Johan W. Mouton
Keyword(s):  
Invasive Aspergillosis ◽  
Aspergillus Fumigatus ◽  
Murine Model ◽  
Antifungal Agent ◽  
In Vivo Efficacy

ABSTRACT The antifungal agent flucytosine was found to be active in vitro against Aspergillus fumigatus isolates when the MIC was determined at pH 5.0 instead of pH 7.0. The in vitro MIC at pH 5.0 corresponded to the in vivo efficacy of flucytosine monotherapy in a murine model of invasive aspergillosis.

scholarly journals 2599. Studying the Effects of Altering Histone Modification on Aspergillus fumigatus Virulence

2019 ◽  
Vol 6 (Supplement_2) ◽  
pp. S903-S903
Author(s):  
Pam Lee ◽  
Hong Liu ◽  
Scott Filler
Keyword(s):  
Invasive Aspergillosis ◽  
Aspergillus Fumigatus ◽  
Histone Modification ◽  
Histone Deacetylase ◽  
Cell Damage ◽  
Invasive Pulmonary Aspergillosis ◽  
Epithelial Cell Line ◽  
Saga Complex

Abstract Background As there are few drugs for treating invasive aspergillosis, there is an urgent need for new antifungal agents. Enzymes involved in histone modification are possible antifungal drug targets. We set out to investigate whether genes whose products are involved in histone modifications influence the virulence of Aspergillus fumigatus (Af). Methods Genes whose products were likely involved in histone modification were deleted in strain Af293 using CRISPR-Cas9. Virulence was assessed in a triamcinolone-treated mouse model of invasive pulmonary aspergillosis. The extent of Af-induced damage to the A549 pulmonary epithelial cell line was determined by Cr51 release assay. Results Af genes were selected for investigation based on their homology to genes encoding known histone modifying proteins and their high expression level in vivo. The genes were predicted to encode members of the COMPASS histone methyltransferase complex (cclA/bre2, set2/Afu5g06000), the SAGA histone acetyltransferase complex (spt3, spt8), and the RPDL histone deacetylase complex (hosA). The ΔcclA and Δset2 mutants had significant growth defects on rich media and were not tested further. The Δspt3 and Δspt8 mutants grew normally and had mild conidiation defects. The ΔhosA mutant had wild-type (WT) growth and conidiation in vitro. Mice infected with the WT strain had 100% mortality within 9 days whereas mice infected the Δspt3, Δspt8, and ΔhosA mutants had only 40% mortality by 21 days. The ΔhosA mutant also had impaired capacity to damage pulmonary epithelial cells in vitro. Conclusion Ccla and Set2, components of the COMPASS complex, are required for normal growth in vitro. Spt3 and Spt8, members of the SAGA complex, are required for normal conidiation and virulence. HosA, part of the RPD3L complex, is necessary for maximal virulence and induction of host cell damage. Our results suggest that the HosA histone deacetylase may be a promising drug target for treating invasive aspergillosis. Disclosures All authors: No reported disclosures.

Itraconazole resistance in Aspergillus fumigatus.

1997 ◽  
Vol 41 (6) ◽  
pp. 1364-1368 ◽  
Author(s):  
D W Denning ◽  
K Venkateswarlu ◽  
K L Oakley ◽  
M J Anderson ◽  
N J Manning ◽  
...  
Keyword(s):  
Invasive Aspergillosis ◽  
Aspergillus Fumigatus ◽  
Dna Analysis ◽  
Ergosterol Biosynthesis ◽  
Wild Type ◽  
Mechanisms Of Resistance ◽  
Random Amplification ◽  
Susceptible Isolate

Invasive aspergillosis is an increasingly frequent opportunistic infection in immunocompromised patients. Only two agents, amphotericin B and itraconazole, are licensed for therapy. Itraconazole acts through inhibition of a P-450 enzyme undertaking sterol 14alpha demethylation. In vitro resistance in Aspergillus fumigatus to itraconazole correlated with in vivo outcome has not been previously described. For three isolates (AF72, AF90, and AF91) of A. fumigatus from two patients with invasive aspergillosis itraconazole MICs were elevated. A neutropenic murine model was used to establish the validity of the MICs. The isolates were typed by random amplification of polymorphic DNA. Analysis of sterols, inhibition of cell-free sterol biosynthesis from [14C] mevalonate, quantitation of P-450 content, and [3H]itraconazole concentration in mycelial pellets were used to determine the mechanisms of resistance. The MICs for the three resistant isolates were >16 microg/ml. In vitro resistance was confirmed in vivo for all three isolates. Molecular typing showed the isolates from the two patients to be genetically distinct. Compared to the susceptible isolate from patient 1, AF72 had a reduced ergosterol content, greater quantities of sterol intermediates, a similar susceptibility to itraconazole in cell-free ergosterol biosynthesis, and a reduced intracellular [3H]itraconazole concentration. In contrast, AF91 and AF92 had slightly higher ergosterol and lower intermediate sterol concentrations, fivefold increased resistance in cell-free systems to the effect of itraconazole on sterol 14alpha demethylation, and intracellular [3H] itraconazole concentrations found in susceptible isolates. Resistance to itraconazole in A. fumigatus is detectable in vitro and is present in wild-type isolates, and at least two mechanisms of resistance are responsible.

In vitro and in vivo characterization of two nonsporulating Aspergillus fumigatus clinical isolates from immunocompetent patients

2019 ◽  
Vol 58 (4) ◽  
pp. 543-551
Author(s):  
Zheng Zhang ◽  
Yuan Jiang ◽  
Jun Chen ◽  
Peiying Chen ◽  
Qingtao Kong ◽  
...  
Keyword(s):  
Invasive Aspergillosis ◽  
Aspergillus Fumigatus ◽  
Pathogenic Fungus ◽  
Antifungal Drugs ◽  
Causative Role ◽  
Immunocompromised Patients ◽  
Pulmonary Aspergillosis ◽  
Brla Gene

Abstract Aspergillus fumigatus is a pathogenic fungus responsible for invasive aspergillosis (IA). Typically, it can produce abundant conidia to survive and spread. The infection by A. fumigatus usually occurs in immunocompromised patients due to failed clearance of inhaled conidia. However, the incidence of aspergillosis in immunocompetent hosts has been increasing, the pathogenesis of which is still unknown. Our team previously obtained two clinical nonsporulating A. fumigatus isolates from non-immunocompromised patients, which only have the form of hyphae. This present study demonstrated the in vitro and in vivo characteristics of the two nonsporulating A. fumigatus isolates and verified that their conidiation defects are associated to abolished expression of the sporulation-related central regulatory pathway brlA gene. In addition, we confirmed the mutation site of brlA gene (c.657_660delTCCT) contributes to the nonsporulating phenotype in one clinical isolate. Plate assay showed that the two nonsporulating isolates have a similar resistance to antifungal drugs, cell wall disturbing substances, and oxidative stress compared with the wild-type reference Af293. Most important of all, we employed an immunocompetent mouse model to mimic the pathogenesis of pulmonary aspergillosis in non-immunocompromised patients. It revealed that the hyphae of two nonsporulating isolates and Af293 have similar virulence in immunocompetent hosts. Interestingly, the hyphae fragments of Af293 but not conidia are able to induce invasive aspergillosis in immunocompetent mice. In conclusion, our study indicate that the form of hyphae may play a dominant causative role in pulmonary aspergillosis of immunocompetent hosts rather than conidia.

In vitro activity of APX2041, a new GWT1-inhibitor and in vivo efficacy of the prodrug APX2104 against Aspergillus fumigatus

2021 ◽  
Author(s):  
Shareef K. Shaheen ◽  
Praveen R. Juvvadi ◽  
John Allen IV ◽  
E. Keats Shwab ◽  
D. Christopher Cole ◽  
...  
Keyword(s):  
Invasive Aspergillosis ◽  
Aspergillus Fumigatus ◽  
Vitro Activity ◽  
Prolonged Survival ◽  
In Vitro Activity ◽  
Wild Type ◽  
In Vivo Efficacy ◽  
Resistant Strains

Invasive aspergillosis (IA) due to Aspergillus fumigatus is a deadly infection for which new antifungal therapies are needed. Here we demonstrate the efficacy of a Gwt1 inhibitor, APX2041, and its prodrug, APX2104, against A. fumigatus . The wild-type, azole-resistant and echinocandin-resistant A. fumigatus strains were equally susceptible to APX2041 in vitro . APX2104 treatment in vivo significantly prolonged survival of neutropenic mice challenged with the wild-type and azole-resistant strains, revealing APX2104 as a potentially promising therapeutic against IA.

scholarly journals Bioluminescent Aspergillus fumigatus, a New Tool for Drug Efficiency Testing and In Vivo Monitoring of Invasive Aspergillosis

2008 ◽  
Vol 74 (22) ◽  
pp. 7023-7035 ◽  
Author(s):  
Matthias Brock ◽  
Grégory Jouvion ◽  
Sabrina Droin-Bergère ◽  
Olivier Dussurget ◽  
Marie-Anne Nicola ◽  
...  
Keyword(s):  
Invasive Aspergillosis ◽  
Aspergillus Fumigatus ◽  
Light Emission ◽  
Screening Method ◽  
Growth Conditions ◽  
Antifungal Drugs ◽  
In Vivo Studies ◽  
Drug Efficiency

ABSTRACT Aspergillus fumigatus is the main cause of invasive aspergillosis in immunocompromised patients, and only a limited number of drugs for treatment are available. A screening method for new antifungal compounds is urgently required, preferably an approach suitable for in vitro and in vivo studies. Bioluminescence imaging is a powerful tool to study the temporal and spatial resolutions of the infection and the effectiveness of antifungal drugs. Here, we describe the construction of a bioluminescent A. fumigatus strain by fusing the promoter of the glyceraldehyde-3-phosphate dehydrogenase gene from A. fumigatus with the luciferase gene from Photinus pyralis to control the expression of the bioluminescent reporter. A. fumigatus transformed with this construct revealed high bioluminescence under all tested growth conditions. Furthermore, light emission correlated with the number of conidia used for inoculation and with the biomass formed after different incubation times. The bioluminescent strains were suitable to study the effectiveness of antifungals in vitro by several independent methods, including the determination of light emission with a microplate reader and the direct visualization of light emission with an IVIS 100 system. Moreover, when glucocorticoid-treated immunosuppressed mice were infected with a bioluminescent strain, light emission was detected from infected lungs, allowing the visualization of the progression of invasive aspergillosis. Therefore, this new bioluminescence tool is suitable to study the in vitro effectiveness of drugs and the disease development, localization, and burden of fungi within tissues and may also provide a powerful tool to study the effectiveness of antifungals in vivo.

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