Extracellular vesicles: novel communicators in lung diseases

Abstract

The lung is the organ with the highest vascular density in the human body. It is therefore perceivable that the endothelium of the lung contributes significantly to the circulation of extracellular vesicles (EVs), which include exosomes, microvesicles, and apoptotic bodies. In addition to the endothelium, EVs may arise from alveolar macrophages, fibroblasts and epithelial cells. Because EVs harbor cargo molecules, such as miRNA, mRNA, and proteins, these intercellular communicators provide important insight into the health and disease condition of donor cells and may serve as useful biomarkers of lung disease processes. This comprehensive review focuses on what is currently known about the role of EVs as markers and mediators of lung pathologies including COPD, pulmonary hypertension, asthma, lung cancer and ALI/ARDS. We also explore the role EVs can potentially serve as therapeutics for these lung diseases when released from healthy progenitor cells, such as mesenchymal stem cells.

Fig. 1

Biogenesis of various forms of extracellular vesicles from a eukaryotic cell. Exosomes are generated through multivesicular bodies (MVB) and intraluminal vesicles (ILV) formation whereas microvesicles/microparticles and apoptotic bodies are vesicles generated through blebbing of plasma membrane

Fig. 2

Illustration showing release of various types of extracellular vesicles and their miRNA content released from different cell types/body fluids in various lung complications