Extracellular vesicles (EVs) are important elements of intercellular communication.
A plethora of different, occasionally even opposite, physiologic and pathologic effects
have been attributed to these vesicles in the last decade. A direct comparison of
individual observations is however hampered by the significant differences in the
way of elicitation, collection, handling, and storage of the investigated vesicles.
In the current work, we carried out a careful comparative study on 3, previously characterized
types of EVs produced by neutrophilic granulocytes. We investigated in parallel the
modulation of multiple blood-related cells and functions by medium-sized vesicles.
We show that EVs released from resting neutrophils exert anti-inflammatory action
by reducing production of reactive oxygen species (ROS) and cytokine release from
neutrophils. In contrast, vesicles generated upon encounter of neutrophils with opsonized
particles rather promote proinflammatory processes as they increase production of
ROS and cytokine secretion from neutrophils and activate endothelial cells. EVs released
from apoptosing cells were mainly active in promoting coagulation. We thus propose
that EVs are "custom made," acquiring selective capacities depending on environmental
factors prevailing at the time of their biogenesis.