Protocol for isolating extracellular vesicles from human or mouse airway macrophages for functional assays and in vivo or in vitro experimentation.

Macrophages are key players in host defense and lung injury, and their crosstalk with other cells dictates the course of the inflammatory response and tissue remodeling. Here, we present a protocol for isolating extracellular vesicles (EVs) from human bronchoalveolar lavage fluid (BALF) and for generating EVs from primary human or murine alveolar macrophages following stimulation by cigarette smoke extract. Furthermore, we describe how to measure matrix metalloproteinase (MMP)-12 activity on macrophage-derived EVs using a Förster resonance energy transfer assay.