ADAMTS13 Regulates Neutrophil Recruitment in a Mouse Model of Invasive Pulmonary Aspergillosis

Blood ◽  
2014 ◽  
Vol 124 (21) ◽  
pp. 4109-4109
Author(s):  
Markus Radsak ◽  
Steve Prüfer ◽  
Katharina Ebner ◽  
Michael Weber ◽  
Sebastian Reuter ◽  
...  
Keyword(s):  
Inflammatory Response ◽  
Mouse Model ◽  
Aspergillus Fumigatus ◽  
Fungal Infections ◽  
Invasive Pulmonary Aspergillosis ◽  
Polymorphonuclear Neutrophils ◽  
Formyl Peptide Receptor ◽  
Wild Type ◽  
Pulmonary Aspergillosis

Abstract Von Willebrand factor (VWF) is secreted as an acute phase protein during inflammation. The main mechanism regulating the size and prothrombotic activity of VWF is the specific proteolytic activity of ADAMTS-13. To determine the relevance of this regulatory pathway for the innate inflammatory response by polymorphonuclear neutrophils (PMN), we employed a mouse model of invasive pulmonary aspergillosis (IPA) where PMN functionality is crucial for fungal clearance and survival. IPA was induced by intratracheal application of Aspergillus fumigatus conidia in wild-type (129/Sv/Pas) or Adamts13 deficient (Adamts13-/-) mice. After PMN depletion using a anti-Gr-1 specific antibody, all mice infected with Aspergillus fumigatus conidia developed neutropenia and succumbed due to lethal IPA. In contrast, all undepleted wild-type mice survived the infection. Interestingly, Aspergillus fumigatus infection in Adamts13-/- mice was lethal in 20% of the animals displaying a more severe course of IPA, as indicated by an increased fungal burden in lung homogenates along with increased levels of albumin and the inflammatory mediators IL-1β, IL-6, TNF-α, KC and MCP-1 in the bronchio-alveolar lavage fluid (BALF) compared to wild-type controls. Beyond this, we observed a decreased number of PMN in BALF of infected Adamts13-/- mice compared to wild-type mice. Lung histology sections demonstrated a more pronounced perivascular leukocyte infiltration in further support of a dysregulated inflammatory response in Adamts13-/- mice. Importantly, we observed no general defect in the activation of neutrophil effector functions as demonstrated by the normal induction of the oxidative burst, phagocytosis, degranulation, L-selectin shedding and apoptosis in response to formyl-peptide receptor agonists or exposure to Aspergillus fumigatus conidia or hyphae in vitro. Therefore, we conclude that the proteolytic regulation of VWF by ADAMTS-13 in an important mechanism to control PMN recruitment in the regulation of the innate inflammatory response in invasive fungal infections. Disclosures Radsak: Celgene: Research Funding.

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 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 The Small GTPase RacA Mediates Intracellular Reactive Oxygen Species Production, Polarized Growth, and Virulence in the Human Fungal Pathogen Aspergillus fumigatus

2010 ◽  
Vol 10 (2) ◽  
pp. 174-186 ◽  
Author(s):  
Haiyan Li ◽  
Bridget M. Barker ◽  
Nora Grahl ◽  
Srisombat Puttikamonkul ◽  
Jeremey D. Bell ◽  
...  
Keyword(s):  
Reactive Oxygen Species ◽  
Aspergillus Fumigatus ◽  
Invasive Pulmonary Aspergillosis ◽  
Reactive Oxygen ◽  
Small Gtpase ◽  
Oxygen Species ◽  
Wild Type ◽  
Content Type ◽  
Diphenylene Iodonium

ABSTRACTAspergillus fumigatusis the predominant mold pathogen in immunocompromised patients. In this study, we present the first characterization of the small GTPase RacA inA. fumigatus. To gain insight into the function ofracAin the growth and pathogenesis ofA. fumigatus, we constructed a strain that lacks a functionalracAgene. The ΔracAstrain showed significant morphological defects, including a reduced growth rate and abnormal conidiogenesis on glucose minimal medium. In the ΔracAstrain, apical dominance in the leading hyphae is lost and, instead, multiple axes of polarity emerge. Intriguingly, superoxide production at the hyphal tips was reduced by 25% in the ΔracAstrain. Treatment of wild-type hyphae with diphenylene iodonium, an inhibitor of NADPH oxidase, resulted in phenotypes similar to that of the ΔracAstrain. These data suggest that ΔracAstrain phenotypes may be due to a reduction or alteration in the production of reactive oxygen species. Most surprisingly, despite these developmental and growth abnormalities, the ΔracAstrain retained at least wild-type virulence in both an insect model and two immunologically distinct murine models of invasive pulmonary aspergillosis. These results demonstrate thatin vitrogrowth phenotypes do not always correlate within vivovirulence and raise intriguing questions about the role of RacA inAspergillusvirulence.

scholarly journals APX001 Is Effective in the Treatment of Murine Invasive Pulmonary Aspergillosis

2018 ◽  
Vol 63 (2) ◽  
pp. e01713-18 ◽  
Author(s):  
Teclegiorgis Gebremariam ◽  
Sondus Alkhazraji ◽  
Abdullah Alqarihi ◽  
Heewon H. Jeon ◽  
Yiyou Gu ◽  
...  
Keyword(s):  
Fungal Infections ◽  
Histopathological Examination ◽  
Invasive Pulmonary Aspergillosis ◽  
Human Pharmacokinetics ◽  
Immunosuppressed Patient ◽  
Cytochrome P450 Enzymes ◽  
Pulmonary Aspergillosis ◽  
Minimum Effective Concentration ◽  
Content Type

ABSTRACTInvasive pulmonary aspergillosis (IPA) due toAspergillus fumigatusis a serious fungal infection in the immunosuppressed patient population. Despite the introduction of new antifungal agents, mortality rates remain high, and new treatments are needed. The novel antifungal APX001A targets the conserved Gwt1 enzyme required for the localization of glycosylphosphatidylinositol-anchored mannoproteins in fungi. We evaluated thein vitroactivity of APX001A againstA. fumigatusand thein vivoactivity of its prodrug APX001 in an immunosuppressed mouse model of IPA. APX001A inhibited the growth ofA. fumigatuswith a minimum effective concentration of 0.03 μg/ml. The use of 50 mg/kg 1-aminobenzotriazole (ABT), a suicide inhibitor of cytochrome P450 enzymes, enhanced APX001A exposures (area under the time-concentration curve [AUC]) 16- to 18-fold and enhanced serum half-life from ∼1 to 9 h, more closely mimicking human pharmacokinetics. We evaluated the efficacy of APX001 (with ABT) in treating murine IPA compared to posaconazole treatment. Treatment of mice with 78 mg/kg once daily (QD), 78 mg/kg twice daily, or 104 mg/kg QD APX001 significantly enhanced the median survival time and prolonged day 21 postinfection overall survival compared to the placebo. Furthermore, administration of APX001 resulted in a significant reduction in lung fungal burden (4.2 to 7.6 log10conidial equivalents/g of tissue) versus the untreated control and resolved the infection, as judged by histopathological examination. The observed survival and tissue clearance were comparable to a clinically relevant posaconazole dose. These results warrant the continued development of APX001 as a broad-spectrum, first-in-class treatment of invasive fungal infections.

scholarly journals The mitochondrial protein Bak is pivotal for gliotoxin-induced apoptosis and a critical host factor of Aspergillus fumigatus virulence in mice

2006 ◽  
Vol 174 (4) ◽  
pp. 509-519 ◽  
Author(s):  
Julian Pardo ◽  
Christin Urban ◽  
Eva M. Galvez ◽  
Paul G. Ekert ◽  
Uwe Müller ◽  
...  
Keyword(s):  
Aspergillus Fumigatus ◽  
Molecular Basis ◽  
Mammalian Cells ◽  
Fungal Infections ◽  
Apoptotic Cell ◽  
Mitochondrial Protein ◽  
Wild Type ◽  
Apoptotic Pathway

Aspergillus fumigatus infections cause high levels of morbidity and mortality in immunocompromised patients. Gliotoxin (GT), a secondary metabolite, is cytotoxic for mammalian cells, but the molecular basis and biological relevance of this toxicity remain speculative. We show that GT induces apoptotic cell death by activating the proapoptotic Bcl-2 family member Bak, but not Bax, to elicit the generation of reactive oxygen species, the mitochondrial release of apoptogenic factors, and caspase-3 activation. Activation of Bak by GT is direct, as GT triggers in vitro a dose-dependent release of cytochrome c from purified mitochondria isolated from wild-type and Bax- but not Bak-deficient cells. Resistance to A. fumigatus of mice lacking Bak compared to wild-type mice demonstrates the in vivo relevance of this GT-induced apoptotic pathway involving Bak and suggests a correlation between GT production and virulence. The elucidation of the molecular basis opens new strategies for the development of therapeutic regimens to combat A. fumigatus and related fungal infections.

scholarly journals The Aspergillus fumigatus Mismatch Repair MSH2 Homolog Is Important for Virulence and Azole Resistance

mSphere ◽  
2019 ◽  
Vol 4 (4) ◽  
Author(s):  
Thaila Fernanda dos Reis ◽  
Lilian Pereira Silva ◽  
Patrícia Alves de Castro ◽  
Rafaela Andrade do Carmo ◽  
Marjorie Mendes Marini ◽  
...  
Keyword(s):  
Aspergillus Fumigatus ◽  
Mismatch Repair ◽  
Genetic Instability ◽  
Galleria Mellonella ◽  
Fungal Infections ◽  
Invasive Pulmonary Aspergillosis ◽  
Azole Resistance ◽  
Repair System ◽  
Wild Type ◽  
Content Type

ABSTRACT The genetic stability of every living organism depends on accurate DNA replication and repair systems. Here, we investigated the Aspergillus fumigatus MSH2 mismatch repair (MMR) gene MshA and how it impacts virulence and the evolution of azole resistance. We examined mshA gene variation in 62 environmental and clinical A. fumigatus strains. We have observed 12 strains with variants (18.2%), and 8 strains among them showed missense variants. We demonstrated that A. fumigatus mshA null mutants are haploid and have conserved karyotypes with discrete gross chromosomal rearrangements. The ΔmshA strains are not sensitive to several DNA-damaging agents. The lack of mshA caused a significant reduction of virulence of A. fumigatus in a neutropenic murine model of invasive pulmonary aspergillosis and in the invertebrate alternative model Galleria mellonella. Wild-type and ΔmshA populations did not show any significant changes in drug resistance acquisition after they were transferred 10 times in minimal medium in the absence of any stress. However, these populations rapidly acquired virulence in the ΔmshA background and high levels of resistance to posaconazole in the presence of this drug (at least 200-fold-higher levels of resistance than those derived from the wild-type strain). Taken together, these results suggest that genetic instability caused by ΔmshA mutations can confer an adaptive advantage, mainly increasing posaconazole resistance and virulence acquisition. IMPORTANCE Invasive aspergillosis (IA) has emerged as one of the most common life-threatening fungal diseases in immunocompromised patients, with mortality rates as high as 90%. Systemic fungal infections such as IA are usually treated with triazoles; however, epidemiological research has shown that the prevalence of azole-resistant Aspergillus fumigatus isolates has increased significantly over the last decade. There is very little information about the importance of genomic stability for A. fumigatus population structure, azole resistance, and virulence. Here, we decided to investigate whether the mismatch repair system could influence A. fumigatus azole resistance and virulence, focusing on one of the components of this system, MSH2. Although the mutation frequency of mshA (the A. fumigatus MSH2 homologue) is low in environmental and clinical isolates, our results indicate that loss of mshA function can provide increased azole resistance and virulence when selected for. These results demonstrate the importance of genetic instability in A. fumigatus as a possible mechanism of evolving azole resistance and establishing fitness in the host.

scholarly journals Posaconazole Prophylaxis in Experimental Azole-Resistant Invasive Pulmonary Aspergillosis

2014 ◽  
Vol 59 (3) ◽  
pp. 1487-1494 ◽  
Author(s):  
Seyedmojtaba Seyedmousavi ◽  
Johan W. Mouton ◽  
Willem J. G. Melchers ◽  
Paul E. Verweij
Keyword(s):  
Invasive Aspergillosis ◽  
Aspergillus Fumigatus ◽  
Murine Model ◽  
Pulmonary Infection ◽  
Invasive Pulmonary Aspergillosis ◽  
Clinical Isolates ◽  
Wild Type ◽  
Breakthrough Infection ◽  
Pulmonary Aspergillosis ◽  
Content Type

ABSTRACTWe investigated the efficacy of posaconazole prophylaxis in preventing invasive aspergillosis due to azole-resistantAspergillus fumigatusisolates. Using a neutropenic murine model of pulmonary infection, posaconazole prophylaxis was evaluated using three isogenic clinical isolates, with posaconazole MICs of 0.063 mg/liter (wild type), 0.5 mg/liter (F219I mutation), and 16 mg/liter. A fourth isolate harboring TR34/L98H (MIC of 0.5 mg/liter) was also tested. Posaconazole prophylaxis was effective inA. fumigatuswith posaconazole MICs of ≤0.5 mg/liter, where 100% survival was reached. However, breakthrough infection was observed in mice infected with the isolate for which the posaconazole MIC was >16 mg/liter.

scholarly journals Absence of Respiratory Burst in X-linked Chronic Granulomatous Disease Mice Leads to Abnormalities in Both Host Defense and Inflammatory Response to Aspergillus fumigatus

1997 ◽  
Vol 185 (2) ◽  
pp. 207-218 ◽  
Author(s):  
David E. Morgenstern ◽  
Mary A.C. Gifford ◽  
Ling Lin Li ◽  
Claire M. Doerschuk ◽  
Mary C. Dinauer
Keyword(s):  
Inflammatory Response ◽  
Aspergillus Fumigatus ◽  
Chronic Granulomatous Disease ◽  
Alveolar Macrophages ◽  
Respiratory Burst ◽  
Pulmonary Inflammation ◽  
Clinical Manifestations ◽  
Granulomatous Disease ◽  
Wild Type

Mice with X-linked chronic granulomatous disease (CGD) generated by targeted disruption of the gp91phox subunit of the NADPH–oxidase complex (X-CGD mice) were examined for their response to respiratory challenge with Aspergillus fumigatus. This opportunistic fungal pathogen causes infection in CGD patients due to the deficient generation of neutrophil respiratory burst oxidants important for damaging A. fumigatus hyphae. Alveolar macrophages from X-CGD mice were found to kill A. fumigatus conidia in vitro as effectively as alveolar macrophages from wild-type mice. Pulmonary disease in X-CGD mice was observed after administration of doses ranging from 105 to 48 spores, none of which produced disease in wild-type mice. Higher doses produced a rapidly fatal bronchopneumonia in X-CGD mice, whereas progression of disease was slower at lower doses, with development of chronic inflammatory lesions. Marked differences were also observed in the response of X-CGD mice to the administration of sterilized Aspergillus hyphae into the lung. Within 24 hours of administration, X-CGD mice had significantly higher numbers of alveolar neutrophils and increased expression of the proinflammatory cytokines IL-1β and TNF-α relative to the responses seen in wild-type mice. By one week after administration, pulmonary inflammation was resolving in wild-type mice, whereas X-CGD mice developed chronic granulomatous lesions that persisted for at least six weeks. This is the first experimental evidence that chronic inflammation in CGD does not always result from persistent infection, and suggests that the clinical manifestations of this disorder reflect both impaired microbial killing as well as other abnormalities in the inflammatory response in the absence of a respiratory burst.

scholarly journals TLR7 expression aggravates invasive pulmonary Aspergillosis by suppressing anti-Aspergillus immunity of macrophages

2021 ◽  
Author(s):  
Banglao Xu ◽  
Qin Luo ◽  
Yi Gong ◽  
Jiaxi Li ◽  
Ju Cao
Keyword(s):  
Aspergillus Fumigatus ◽  
Knockout Mice ◽  
Tissue Injury ◽  
Critical Role ◽  
Invasive Pulmonary Aspergillosis ◽  
Negative Regulator ◽  
Immune Recognition ◽  
Wild Type

Toll-like receptors (TLRs) play a critical role in early immune recognition of Aspergillus, which can regulate host defense during invasive pulmonary Aspergillosis (IPA). However, the role of TLR7 in the pathogenesis of IPA remains unknown. In this study, an in vivo model of IPA was established to investigate the contribution of TLR7 to host anti-Aspergillus immunity upon invasive pulmonary Aspergillus fumigatus infection. The effects of TLR7 on phagocytosis and killing capacities of A. fumigatus by macrophages and neutrophils were investigated in vitro. We found that TLR7 knockout mice exhibited lower lung inflammatory response and tissue injury, higher fungal clearance, and greater survival in an in vivo model of IPA as compared with wild-type mice. TLR7 activation by R837 ligand led wild-type mice more susceptible to invasive pulmonary Aspergillus fumigatus infection. Macrophages, but not neutrophils, were required for the protection against IPA observed in TLR7 knockout mice. Mechanistically, TLR7 impaired phagocytosis and killing of A. fumigatus by macrophages, but not neutrophils. Together, these data identify TLR7 as an important negative regulator of anti-Aspergillus innate immunity in IPA, and we propose that targeting TLR7 may be beneficial in treatment of IPA.

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