Background: Chronic Obstructive Pulmonary Disease (COPD) and Idiopathic Pulmonary Fibrosis (IPF) are chronic, progressive lung ailments which are characterized by distinct pathologies. Early detection biomarkers and disease mechanisms for these debilitating diseases are lacking. Exosomes are small extracellular vesicles attributed to carry proteins, mRNA, miRNA and sncRNA to facilitate cell-to-cell communication under normal and diseased conditions. Exosomal miRNAs have been studied in relation to many diseases. However, there is little to no knowledge regarding the miRNA population of BALF or the lung tissue derived exosomes in COPD and IPF. Here, we determined and compared the miRNA profiles of BALF and lung tissue-derived exosomes from healthy non-smokers, healthy smokers, and patients with COPD and IPF in independent cohorts. Results: Exosome characterization using NanoSight particle tracking and TEM demonstrated that the BALF-derived exosomes were approximately 89.85 nm in size and ~2.95 X 1010 particles/mL. Lung-derived exosomes were ~146.04 nm in size and ~2.38 X 1011 particles/mL. NGS results identified three differentially expressed miRNAs in the BALF, while one in the lung-derived exosomes from COPD patients as compared to healthy non-smokers. Of these, three- and five-fold downregulation of miR-122-5p amongst the lung tissue-derived exosomes from COPD patients as compared to healthy non-smokers and smokers, respectively. Interestingly, there were key 55 differentially expressed miRNAs in the lung tissue-derived exosomes of IPF patients compared to non-smoking controls. Conclusions: Overall, we identified specific miRNAs to develop as biomarkers or targets for pathogenesis of these chronic lung diseases.

In the longtime challenge of identifying specific, easily-detectable and reliable biomarkers of Idiopathic Pulmonary Fibrosis (IPF), bronchoalveolar lavage fluid (BALF) proteomics is providing interesting new insights into its pathogenesis. To the best of our knowledge, the present study is the first shotgun proteomic investigation of EVs isolated from BALF of IPF patients. Our main aim was to characterize the proteome of the vesicular component of BALF and to explore its individual impact on the pathogenesis of IPF. To this purpose, ultracentrifugation was chosen as EVs isolation technique and their purification was assessed by TEM, 2DE and LC-MS/MS. Our 2DE data and scatter plots showed considerable differences between the proteome of EVs and that of whole BALF and of its fluid component. Analysis of protein content and protein functions evidenced that EV proteins are predominantly involved in cytoskeleton remodeling, adenosine signaling, adrenergic signaling, C-peptide signaling and lipid metabolism. Our findings may suggest a wider system involvement in the disease pathogenesis and support the importance of pre-fractioning of complex samples, like BALF, in order to let low-abundant proteins-mediated pathways to emerge.

Coronavirus disease 2019 (COVID-19), caused by the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), mainly affects the respiratory system with some patients rapidly progressing to acute respiratory distress syndrome (ARDS). The most common symptoms of the patients are fever, cough, dyspnea, myalgia, and fatigue. Nasopharyngeal and oropharyngeal swab specimens tested by real-time reverse transcription-polymerase chain reaction (RT-PCR) are the most commonly used methods to diagnose COVID-19. Herein, we investigate and discuss a young case of COVID-19, without any pre-existing medical conditions, whose both nasopharyngeal and oropharyngeal swab tests of SARS-CoV-2 were negative in the prodromal phase. However, after three days, with severe dyspnea and rapidly progressed acute respiratory distress syndrome (ARDS), the case was identified as infected by COVID-19 by testing bronchoalveolar lavage fluid (BALF). The patient was intubated in the intensive care unit (ICU) but expired on the fourth day. This case shows the importance of active and accurate monitoring of the patients showing COVID-19 symptoms. Although the BALF test has a higher exposure risk, it is considered more accurate and recommended if performed by an expert operator.

Fungi of the genus Aspergillus are widespread in the environment where they produce large quantities of airborne conidia. Inhalation of Aspergillus spp. conidia in immunocompromised individuals can cause a wide spectrum of diseases, ranging from hypersensitivity responses to lethal invasive infections. Upon deposition in the lung epithelial surface, conidia encounter and interact with complex microbial communities that constitute the lung microbiota. The lung microbiota has been suggested to influence the establishment and growth of Aspergillus spp. in the human airways. However, the mechanisms underlying this interaction have not yet been sufficiently investigated. In this study, we aimed to evaluate the presence of commensal bacteria antagonistic to Aspergillus in the lung. To this end, we enriched and isolated bacterial strains able to inhibit the germination of conidia from bronchoalveolar lavage fluid (BALF) samples of lung transplant recipients. We used a novel enrichment method based on a soft agar overlay plate assay in which bacteria are directly in contact with conidia and for which inhibition can be readily observed during enrichment. We isolated a total of five bacterial strains, identified as Pseudomonas aeruginosa, and able to inhibit the germination and growth of Aspergillus fumigatus in a soft agar confrontation assay, as well as in a high-throughput multiplate assay. Moreover, we also showed a strong inhibition of A. fumigatus growth on Calu-3 cell culture monolayers. However, the isolated P. aeruginosa strains were shown to cause significant damage to the cell monolayers. Overall, we validated this novel one-step enrichment approach for the isolation of bacterial strains antagonistic to A. fumigatus from BALF samples. This opens up a new venue for targeted enrichment of antagonistic bacterial strains against specific fungal pathogens.

Asthma is the most common chronic disease in children. It is characterized by difficulty in breathing and chronic airway inflammation associated with narrowing of the airways, and airway hyperresponsiveness. If left untreated, asthma can lead to respiratory distress and even death. A number of medications are available and prescribed to manage asthma. Yet despite that, only half of the asthmatic patients are able to control their condition. Extracellular vesicles (EVs) play an important role in transporting contents such as nucleic acids, proteins, and lipids to other cells. While EVs have been extensively studied as biomarkers of various pathological states, evidence indicates that they can play protective and therapeutic roles in mitigating diseases such as cancer, cardiovascular disease and asthma. Here we propose to conduct a systematic review that provides a detailed analysis of the therapeutic effect of EVs in mitigating the primary (inflammation, airway hyperresponsiveness) and secondary outcomes (airway remodelling, molecular indices of cellular signalling, and inflammatory mediators in serum) associated with asthma in preclinical studies.