Role of extracellular vesicles in nanomaterial-induced oxidative stress in aquatic ecotoxicology

Purpose and goal:

The main objective was to evaluate the cellular antioxidant response/oxidative damages and the cargo of extracellular vesicles after nanomaterial exposure. Viability, apoptosis and reactive oxygen species production were measured in fish cell lines (rainbow trout liver, gill and intestinal epithelial cell lines; and zebrafish liver cell line) after short-term titanium dioxide (TiO2) nanoparticle exposure.

Extracellular vesicles (EVs) were isolated and characterized, including morphology, particle number and protein cargo. Expected results and effects: TiO2 had only minor effects on the cellular end-points up to 100ug/mL in fish cell lines.

EVs were isolated and TiO2 NPs were visible on the surface of the vesicles in TEM. STRING analysis of the EV proteomics reviled 16 proteins belonging to oxidoreductase processes where 12 proteins were significantly affected by the combined exposure of positive control Tempol (an artificial antioxidant) and TiO2 NPs, but not by their single exposure.

EVs isolated from control cells or after Tempol exposure had no significant effect on ROS production in control cells or cells with TiO2 NP exposure. Approach and implementation:

TiO2 nanoparticles had only minor effects on the cells or the EVs alone, however when combined with Tempol, an artificial antioxidant, their combined effect significantly affected not only the cellular end-points, but the oxidoreductase proteins of the EV cargo. Further investigation is needed to understand the underlying biological processes of the observed results of the combined exposure of the nanoparticles with Tempol on the oxidoreductase enzymes and proteins of the proteome and whether other biological processes were affected.