Abstract Mast cells have been shown to release extracellular vesicles (EVs) in vitro.
However, EV-mediated mast cell communication in vivo remains unexplored. Primary mast
cells from GFP-transgenic and wild type mice, were grown in the presence or absence
of lipopolysaccharide (LPS), and the secreted EVs were separated from the conditioned
media. Mast cell-derived EVs were next cultured with LPS-naïve mast cells, and the
induction of TNF-α expression was monitored. In addition, primary mast cells were
seeded in diffusion chambers that were implanted into the peritoneal cavities of mice.
Diffusion chambers enabled the release of GFP+ mast cell-derived EVs in vivo into
the peritoneal cavity. Peritoneal lavage cells were assessed for the uptake of GFP+
EVs and for TNF-α production. In vitro, LPS-stimulated mast cell-derived EVs were
efficiently taken up by non-stimulated mast cells, and induced TNF-α expression in
a TLR4, JNK and P38 MAPK dependent manner. In vivo, using implanted diffusion chambers,
we confirmed the release and transmission of mast cell-derived EVs to other mast cells
with subsequent induction of TNF-α expression. These data show an EV-mediated spreading
of pro-inflammatory response between mast cells, and provide the first in vivo evidence
for the biological role of mast cell-derived EVs.
