Novel computational analysis of large transcriptome datasets identifies sets of genes distinguishing chronic obstructive pulmonary disease from healthy lung samples

Chronic obstructive pulmonary disease (COPD) kills over three million people worldwide every year. Despite its high global impact, the knowledge about the underlying molecular mechanisms is still limited. In this study, we aimed to extend the available knowledge by identifying a small set of COPD-associated genes. We analysed different publicly available gene expression datasets containing whole lung tissue (WLT) and airway epithelium (AE) samples from over 400 human subjects for differentially expressed genes (DEGs). We reduced the resulting sets of 436 and 663 DEGs using a novel computational approach that utilises a random depth-first search to identify genes which improve the distinction between COPD patients and controls along the first principle component of the data. Our method identified small sets of 10 and 15 genes in the WLT and AE, respectively. These sets of genes significantly (p

The clinical role of host and bacterial-derived extracellular vesicles in pneumonia

Pneumonia is among the leading causes of morbidity and mortality worldwide. Due to constant evolution of respiratory bacteria and viruses, development of drug resistance and emerging pathogens, it consti-tutes a considerable health care threat. To enable development of novel strategies to control pneumonia, a better understanding of the complex mechanisms of interaction between host cells and infecting patho-gens is vital. Here, we review the roles of host cell and bacterial-derived extracellular vesicles (EVs) in these interactions. We discuss clinical and experimental as well as pathogen-overarching and pathogen-specific evidence for common viral and bacterial elicitors of community-and hospital-acquired pneumonia. Finally, we highlight the potential of EVs for improved management of pneumonia patients and discuss the translational steps to be taken before they can be safely exploited as novel vac-cines, biomarkers, or therapeutics in clinical practice. (c) 2021 The Authors. Published by Elsevier B.V. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/)

Cigarette smoke extract induces the release of extracellular vesicles by airway epithelial cells via cellular carbonyl stress

Introduction: Secreted extracellular vesicles (EVs) participate in multiple processes by transferring proteins and RNA between cells. Yet, their contribution to chronic inflammation in the lungs is largely unexplored. We determined if exposure of airway epithelial cells (AEC) to cigarette smoke extract (CSE) results in release of pro-inflammatory EVs. Using the CSE components H2O2 and acrolein, we determined whether reactive oxygen species or thiol-reactive carbonyl compounds account for CSE-induced EV release.Methods: AEC were exposed for 24h to different concentrations of CSE, H2O2 or acrolein, in some experiments in the presence of the thiol-group bearing antioxidant N-acetylcysteine (NAC). Relative levels of CD63+CD81+ EVs in conditioned media were measured by bead-coupled flow cytometry. Oxidized and total GSH were assessed using a GSH reductase cycling assay.Results: CSE induced EV release in a concentration-dependent manner up to 2.3-fold at 1.5% CSE. This was paralleled by increases in cellular oxidized (3.1 fold) and total (5.8 fold) GSH. Incubation of CSE with GSH resulted in complete GSH oxidation, confirming direct thiol reactivity of CSE. NAC prevented CSE-induced EV-release, likely by scavenging thiol-reactive components of CSE. Similar to CSE, acrolein, but not H2O2, induced EV release in a NAC-reversible manner. Exposure of naïve macrophages to CSE-induced EVs resulted in increased release of TNFα.Conclusion: AEC release an increased quantity of EVs when exposed to CSE. This is likely mediated by reactive carbonyl compounds. These EVs exert pro-inflammatory effects that may contribute to the pathogenesis of COPD