Cationic polystyrene nanoparticle and the sea urchin immune system: biocorona formation, cell toxicity, and multixenobiotic resistance phenotype

Abstract

In order to assess the impact of nanoplastics on marine species, polystyrene nanoparticles (PS NPs) have been largely used as model particles. Here we studied the effects of 50 nm amino-modified PS-NH₂ on Mediterranean sea urchin Paracentrotus lividus immune system cells (coelomocytes) in the presence of celomic fluid (CF) and at different NP concentrations (1, 5, 10, and 25 μg mL⁻¹) and experimental conditions (absence or presence of EDTA). PS-NH₂ acquired a protein corona once incubated with CF, dominated by the toposome precursor protein (TPP). In short-term cultures, a significant concentration- and time-dependent decrease in lysosomal membrane stability and apoptotic-like nuclear alterations were observed in phagocytes upon exposure to PS-NH₂ (10 and 25 µg mL⁻¹) in CF but they resulted abolished in the presence of EDTA confirming the role of TPP in triggering PS-NH₂-coelomocytes interaction and toxicity. PS-NH₂ did not alter MXR phenotype but the observed dose-dependent decrease in calcein accumulation suggests the ability of PS-NH₂ to affect pump’s efflux activity. Overall results encourage additional studies on positively charged nanoplastics, since the observed effects on sea urchin coelomocytes as well as the TPP corona formation might represent a first step for addressing their impact on sensitive marine species.

Keywords:

• Nanoplastics
• sea urchin coelomocytes
• protein-corona
• toposome
• MXR

Acknowledgements

We would like to thank Prof. Andrea Massimo Atrei and his collaborator Dr. Marianna Uva of the Department of Biotechnologies, Chemistry and Pharmacy of the University of Siena for access to the DLS facility located at the Interuniversity Center for Advanced Medical Systems (CRISMA) at Colle di Val d'Elsa (Siena), Italy.

Disclosure statement

No potential conflict of interest was reported by the authors.

Additional information

Funding

This work was done in the framework of the project PLANET (Plastics in the Antarctic Environment – PNRA 14_00090) funded by the Italian National Antarctic Research Program and coordinated by the Department of Physical, Earth and Environmental Sciences, University of Siena (Italy). L. F. Marques-Santos acknowledges support from the Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq – Research fellowship number 234109/2014-9).