scholarly journals 455: Aspergillus fumigatus persistence and infection in cystic fibrosis: Adaptation to hypoxia and in vivo HOG pathway mutation

2021 ◽  
Vol 20 ◽  
pp. S215
Author(s):  
B. Ross ◽  
L. Lofgren ◽  
A. Ashare ◽  
J. Stajich ◽  
R. Cramer
Keyword(s):  
Cystic Fibrosis ◽  
Aspergillus Fumigatus ◽  
Adaptation To Hypoxia ◽  
Hog Pathway

scholarly journals Studies of Pseudomonas aeruginosa Mutants Indicate Pyoverdine as the Central Factor in Inhibition of Aspergillus fumigatus Biofilm

2017 ◽  
Vol 200 (1) ◽  
Author(s):  
Gabriele Sass ◽  
Hasan Nazik ◽  
John Penner ◽  
Hemi Shah ◽  
Shajia Rahman Ansari ◽  
...  
Keyword(s):  
Cystic Fibrosis ◽  
Pseudomonas Aeruginosa ◽  
Aspergillus Fumigatus ◽  
Fungal Pathogens ◽  
Human Pathogens ◽  
Biofilm Growth ◽  
Content Type ◽  
Iron Deprivation

ABSTRACT Pseudomonas aeruginosa and Aspergillus fumigatus are common opportunistic bacterial and fungal pathogens, respectively. They often coexist in airways of immunocompromised patients and individuals with cystic fibrosis, where they form biofilms and cause acute and chronic illnesses. Hence, the interactions between them have long been of interest and it is known that P. aeruginosa can inhibit A. fumigatus in vitro. We have approached the definition of the inhibitory P. aeruginosa molecules by studying 24 P. aeruginosa mutants with various virulence genes deleted for the ability to inhibit A. fumigatus biofilms. The ability of P. aeruginosa cells or their extracellular products produced during planktonic or biofilm growth to affect A. fumigatus biofilm metabolism or planktonic A. fumigatus growth was studied in agar and liquid assays using conidia or hyphae. Four mutants, the pvdD pchE, pvdD, lasR rhlR, and lasR mutants, were shown to be defective in various assays. This suggested the P. aeruginosa siderophore pyoverdine as the key inhibitory molecule, although additional quorum sensing-regulated factors likely contribute to the deficiency of the latter two mutants. Studies of pure pyoverdine substantiated these conclusions and included the restoration of inhibition by the pyoverdine deletion mutants. A correlation between the concentration of pyoverdine produced and antifungal activity was also observed in clinical P. aeruginosa isolates derived from lungs of cystic fibrosis patients. The key inhibitory mechanism of pyoverdine was chelation of iron and denial of iron to A. fumigatus. IMPORTANCE Interactions between human pathogens found in the same body locale are of vast interest. These interactions could result in exacerbation or amelioration of diseases. The bacterium Pseudomonas aeruginosa affects the growth of the fungus Aspergillus fumigatus. Both pathogens form biofilms that are resistant to therapeutic drugs and host immunity. P. aeruginosa and A. fumigatus biofilms are found in vivo, e.g., in the lungs of cystic fibrosis patients. Studying 24 P. aeruginosa mutants, we identified pyoverdine as the major anti-A. fumigatus compound produced by P. aeruginosa. Pyoverdine captures iron from the environment, thus depriving A. fumigatus of a nutrient essential for its growth and metabolism. We show how microbes of different kingdoms compete for essential resources. Iron deprivation could be a therapeutic approach to the control of pathogen growth.

scholarly journals Aspergillus fumigatus In-Host HOG Pathway Mutation for Cystic Fibrosis Lung Microenvironment Persistence

mBio ◽  
2021 ◽  
Vol 12 (4) ◽  
Author(s):  
Brandon S. Ross ◽  
Lotus A. Lofgren ◽  
Alix Ashare ◽  
Jason E. Stajich ◽  
Robert A. Cramer
Keyword(s):  
Cystic Fibrosis ◽  
Aspergillus Fumigatus ◽  
Disease Progression ◽  
Allergic Bronchopulmonary Aspergillosis ◽  
Clinical Manifestations ◽  
Cystic Fibrosis Lung ◽  
Hog Pathway ◽  
Content Type

Aspergillus fumigatus infection causes a spectrum of clinical manifestations. For individuals with cystic fibrosis (CF), allergic bronchopulmonary aspergillosis (ABPA) is an established complication, but there is a growing appreciation for A. fumigatus airway persistence in CF disease progression.

scholarly journals Aspergillus fumigatusIn-Host HOG pathway mutation for Cystic Fibrosis Lung Microenvironment Persistence

2021 ◽  
Author(s):  
Brandon S. Ross ◽  
Lotus A. Lofgren ◽  
Alix Ashare ◽  
Jason E. Stajich ◽  
Robert A. Cramer
Keyword(s):  
Cystic Fibrosis ◽  
Aspergillus Fumigatus ◽  
Antifungal Therapy ◽  
Clinical Management ◽  
Atmospheric Oxygen ◽  
Allergic Bronchopulmonary Aspergillosis ◽  
Clinical Manifestations ◽  
Low Oxygen ◽  
Hog Pathway ◽  
Unique Allele

AbstractThe prevalence ofAspergillus fumigatuscolonization in individuals with Cystic Fibrosis (CF) and subsequent fungal persistence in the lung is increasingly recognized. However, there is no consensus for clinical management ofA. fumigatusin CF individuals, due largely to uncertainty surroundingA. fumigatusCF pathogenesis and virulence mechanisms. To address this gap in knowledge, a longitudinal series ofA. fumigatusisolates from an individual with CF were collected over 4.5 years. Isolate genotypes were defined with whole genome sequencing that revealed both transitory and persistentA. fumigatusin the lung. Persistent lineage isolates grew most readily in a low oxygen culture environment and conidia were more sensitive to oxidative stress inducing conditions compared to non-persistent isolates. Closely related persistent isolates harbor a unique allele of the high osmolarity glycerol (HOG) pathway mitogen activated protein kinase kinase, Pbs2 (pbs2C2). Data suggest this novelpbs2C2allele arosein vivoand is necessary for the fungal response to osmotic stress in a low oxygen environment through hyperactivation of the HOG (SakA) signaling pathway. Hyperactivation of the HOG pathway throughpbs2C2comes at the cost of decreased conidia stress resistance in the presence of atmospheric oxygen levels. These novel findings shed light on pathoadaptive mechanisms ofA. fumigatusin CF, lay the foundation for identifying persistentA. fumigatusisolates that may require antifungal therapy, and highlight considerations for successful culture of persistent fungal CF isolates.ImportanceAspergillus fumigatusinfection causes a spectrum of clinical manifestations. For individuals with Cystic Fibrosis (CF), Allergic Bronchopulmonary Aspergillosis (ABPA) is an established complication, but there is a growing appreciation forA. fumigatusairway persistence in CF disease progression. There currently is little consensus for clinical management ofA. fumigatuslong-term culture positivity in CF. A better understanding ofA. fumigatuspathogenesis mechanisms in CF is expected to yield insights into when antifungal therapies are warranted. Here, a 4.5-year longitudinal collection ofA. fumigatusisolates identified a persistent lineage that harbors a unique allele of the Pbs2 MAPKK necessary for unique CF-relevant stress phenotypes. Importantly forA. fumigatusCF patient diagnostics, this allele provides increased CF lung fitness at a cost of reducedin vitrogrowth in standard laboratory conditions. These data illustrate a molecular mechanism forA. fumigatusCF lung persistence with implications for diagnostics and antifungal therapy.

Preliminary Report of In vitro and In vivo Effectiveness of Dornase Alfa on SARS-CoV-2 Infection (Preprint)

2020 ◽  
Author(s):  
Hacer Kuzu Okur ◽  
Koray Yalcin ◽  
Cihan Tastan ◽  
Sevda Demir ◽  
Bulut Yurtsever ◽  
...  
Keyword(s):  
Cystic Fibrosis ◽  
Respiratory Tract ◽  
Mononuclear Cells ◽  
Multiple Organ ◽  
Peripheral Blood Mononuclear ◽  
Dornase Alfa ◽  
Tract Infections ◽  
Adult Peripheral Blood

UNSTRUCTURED Dornase alfa, the recombinant form of the human DNase I enzyme, breaks down neutrophil extracellular traps (NET) that include a vast amount of DNA fragments, histones, microbicidal proteins and oxidant enzymes released from necrotic neutrophils in the highly viscous mucus of cystic fibrosis patients. Dornase alfa has been used for decades in patients with cystic fibrosis to reduce the viscoelasticity of respiratory tract secretions, to decrease the severity of respiratory tract infections, and to improve lung function. Previous studies have linked abnormal NET formations to lung diseases, especially to acute respiratory distress syndrome (ARDS). Coronavirus disease 2019 (COVID-19) pandemic affected more than two million people over the world, resulting in unprecedented health, social and economic crises. The COVID-19, viral pneumonia that progresses to ARDS and even multiple organ failure, is caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). High blood neutrophil levels are an early indicator of SARS-CoV-2 infection and predict severe respiratory diseases. A similar mucus structure is detected in COVID-19 patients due to the accumulation of excessive NET in the lungs. Here, we show our preliminary results with dornase alfa that may have an in-vitro anti-viral effect against SARS-CoV-2 infection in a bovine kidney cell line, MDBK without drug toxicity on healthy adult peripheral blood mononuclear cells. In this preliminary study, we also showed that dornase alfa can promote clearance of NET formation in both an in-vitro and three COVID-19 cases who showed clinical improvement in radiological analysis (2-of-3 cases), oxygen saturation (SpO2), respiratory rate, disappearing of dyspnea and coughing.

scholarly journals Functional and Transcriptional Adaptations of Blood Monocytes Recruited to the Cystic Fibrosis Airway Microenvironment In Vitro

2021 ◽  
Vol 22 (5) ◽  
pp. 2530
Author(s):  
Bijean D. Ford ◽  
Diego Moncada Giraldo ◽  
Camilla Margaroli ◽  
Vincent D. Giacalone ◽  
Milton R. Brown ◽  
...  
Keyword(s):  
Cystic Fibrosis ◽  
Bactericidal Activity ◽  
Scavenger Receptor ◽  
Receptor Expression ◽  
Blood Monocytes ◽  
Bacterial Killing ◽  
Blood Neutrophils ◽  
Vitro Model

Cystic fibrosis (CF) lung disease is dominated by the recruitment of myeloid cells (neutrophils and monocytes) from the blood which fail to clear the lung of colonizing microbes. In prior in vitro studies, we showed that blood neutrophils migrated through the well-differentiated lung epithelium into the CF airway fluid supernatant (ASN) mimic the dysfunction of CF airway neutrophils in vivo, including decreased bactericidal activity despite an increased metabolism. Here, we hypothesized that, in a similar manner to neutrophils, blood monocytes undergo significant adaptations upon recruitment to CFASN. To test this hypothesis, primary human blood monocytes were transmigrated in our in vitro model into the ASN from healthy control (HC) or CF subjects to mimic in vivo recruitment to normal or CF airways, respectively. Surface phenotype, metabolic and bacterial killing activities, and transcriptomic profile by RNA sequencing were quantified post-transmigration. Unlike neutrophils, monocytes were not metabolically activated, nor did they show broad differences in activation and scavenger receptor expression upon recruitment to the CFASN compared to HCASN. However, monocytes recruited to CFASN showed decreased bactericidal activity. RNASeq analysis showed strong effects of transmigration on monocyte RNA profile, with differences between CFASN and HCASN conditions, notably in immune signaling, including lower expression in the former of the antimicrobial factor ISG15, defensin-like chemokine CXCL11, and nitric oxide-producing enzyme NOS3. While monocytes undergo qualitatively different adaptations from those seen in neutrophils upon recruitment to the CF airway microenvironment, their bactericidal activity is also dysregulated, which could explain why they also fail to protect CF airways from infection.

scholarly journals The Multifaceted Roles of MicroRNAs in Cystic Fibrosis

Diagnostics ◽  
2020 ◽  
Vol 10 (12) ◽  
pp. 1102
Author(s):  
Fatima Domenica Elisa De Palma ◽  
Valeria Raia ◽  
Guido Kroemer ◽  
Maria Chiara Maiuri
Keyword(s):  
Cystic Fibrosis ◽  
Respiratory Infections ◽  
Current Knowledge ◽  
Pancreatic Insufficiency ◽  
Clinical Manifestations ◽  
Predictive Biomarkers ◽  
Loss Of Function ◽  
Gene Encoding ◽  
Multisystemic Disease

Cystic fibrosis (CF) is a lifelong disorder affecting 1 in 3500 live births worldwide. It is a monogenetic autosomal recessive disease caused by loss-of-function mutations in the gene encoding the chloride channel cystic fibrosis transmembrane conductance regulator (CFTR), the impairment of which leads to ionic disequilibria in exocrine organs. This translates into a chronic multisystemic disease characterized by airway obstruction, respiratory infections, and pancreatic insufficiency as well as hepatobiliary and gastrointestinal dysfunction. Molecular characterization of the mutational heterogeneity of CFTR (affected by more than 2000 variants) improved the understanding and management of CF. However, these CFTR variants are linked to different clinical manifestations and phenotypes, and they affect response to treatments. Expanding evidence suggests that multisystemic disease affects CF pathology via impairing either CFTR or proteins regulated by CFTR. Thus, altering the expression of miRNAs in vivo could constitute an appealing strategy for developing new CF therapies. In this review, we will first describe the pathophysiology and clinical management of CF. Then, we will summarize the current knowledge on altered miRNAs in CF patients, with a focus on the miRNAs involved in the deregulation of CFTR and in the modulation of inflammation. We will highlight recent findings on the potential utility of measuring circulating miRNAs in CF as diagnostic, prognostic, and predictive biomarkers. Finally, we will provide an overview on potential miRNA-based therapeutic approaches.

Prevalence of Aspergillus fumigatus and other fungal species in the sputum of adult patients with cystic fibrosis

Mycoses ◽  
2003 ◽  
Vol 46 (1-2) ◽  
pp. 19-23 ◽  
Author(s):  
N. Bakare ◽  
V. Rickerts ◽  
J. Bargon ◽  
G. Just-Nübling
Keyword(s):  
Cystic Fibrosis ◽  
Aspergillus Fumigatus ◽  
Fungal Species ◽  
Adult Patients
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