Chronic obstructive pulmonary disease (COPD) is a heterogeneous disease characterised by chronic inflammation and significant airflow obstruction that is not fully reversible, and is one of the leading causes of morbidity and mortality worldwide. Extracellular vesicles (EVs) (including apoptotic bodies, microvesicles and exosomes) are small membrane-bound vesicles released by nearly all cell types and can be found in various bodily fluids including blood, sputum and urine. EVs are key mediators in cell-cell communication due to their ability to exchange information to recipient cells, influencing physiological and pathological conditions using their bioactive cargo (DNA, RNA, miRNA, proteins and other metabolites).
Researchers from the University of Queensland highlight recent evidence of the potential use of EVs as diagnostic and therapeutic biomarkers for COPD managements, as well as EVs potential role in COPD pathogenesis. As EVs have been under intense investigation as diagnostic and therapeutic biomarkers for lung disease, in relation to COPD, key studies have identified EVs as potential biomarkers to distinguish exacerbations from stable state, and to characterise COPD phenotypes. EVs are also linked to key inflammatory mediators in COPD progression. In addition, bacteria and their EV cargo influence the lung microenvironment. Further recent therapeutic approaches and advances have seen EVs bioengineered as novel drug delivery vehicles, which could potentially have clinical utility for lung diseases such as COPD.
Biogenesis of extracellular vesicles in relation to COPD
Environmental factors including air pollution, noxious particles and bacterial/viral infections can influence the bioactive cargo delivered by EVs. EVs biogenesis begins through the formation of intraluminal vesicles inside MVBs which then bud into early endosomes through to late endosomes. MVBs will then fuse with the plasma membrane, causing the release of content into the extracellular space (exosomes) or through outwards budding and fission with the plasma membrane (microvesicles). Apoptotic bodies are formed during programmed cell death through actin-myosin mediated membrane blebbing. COPD, chronic obstructive pulmonary disease; EV, extracellular vesicle; MVBs, multivesicular bodies.