Recently, biological roles of extracellular vesicles (which include among others exosomes,
microvesicles and apoptotic bodies) have attracted substantial attention in various
fields of biomedicine. Here we investigated the impact of sustained exposure of cells
to the fluoroquinolone antibiotic ciprofloxacin on the released extracellular vesicles.
Ciprofloxacin is widely used in humans against bacterial infections as well as in
cell cultures against Mycoplasma contamination. However,
ciprofloxacin is an inducer of oxidative stress and mitochondrial dysfunction of mammalian
cells. Unexpectedly, here we found that ciprofloxacin induced the release of both
DNA (mitochondrial and chromosomal sequences) and DNA-binding proteins on the exofacial
surfaces of small extracellular vesicles referred to in this paper as exosomes. Furthermore,
a label-free optical biosensor analysis revealed DNA-dependent binding of exosomes
to fibronectin. DNA release on the surface of exosomes was not affected any further
by cellular activation or apoptosis induction. Our results reveal for the first time
that prolonged low-dose ciprofloxacin exposure leads to the release of DNA associated
with the external surface of exosomes.
