ZnO nanoparticles effect on integrity of human endothelial cells
|Ewa Stępień 1,2, Dominik Jakubiak , Jacek Wojnarowicz 3, Agnieszka Opalińska 3,4, Witold Łojkowski 3,5|
1. Jagiellonian University Collegium Medicum Department of Clinical Biochemistry, Kopernika 15 a, Kraków 31-501, Poland
Disruption of the intercellular interactions between endothelial cells leads to endothelial dysfunction. The role of nanoparticles in plasma membrane stability, actin cytoskeleton organization and intercellular junctions is unclear. Human umbilical vein endothelial cells were treated with zinc oxide NPs in vitro. Cell shape, adhesiveness and plasma membrane integrity were analyzed by means of optical fluorescence microscopy, scanning electron microscopy and flow cytometry methods. Additionally, lactate dehydrogenase activity assay and annexin V staining were performed. The scanning electron microscopy analysis showed changes in morphology and surface topography. The F-actin organization was typical for migrating cells. Cell membrane damage (significant increase in lactate dehydrogenase release and annexin V staining) was observed in the concentration of ZnO nanoparticles above 30μg/ml. The relationship between ZnO nanoparticles and endothelial dysfunction was clearly established and the importance of cytoskeleton reorganization and loosening of the continuous endothelial monolayer after nanoparticles exposure has been documented. Furthermore, loosing of cell contact diminishes contact-inhibition and activates endothelial cells. Contact-inhibition universally regulates migratory cell proliferation in non-transformed normal cells when neighboring cells are in contact. This phenomenon explains poor regenerative capacity of in vivo human endothelial cells during aging, injury, and surgery. Disrupting of contact inhibition regulated by Ca2+-related adhesion molecules (cadherins), actually activates the canonical Wnt signaling and induces canonicl activation of Wnt pathways. This may also explain why NPs which varied in shape and size and are made from the same substance may have divergent effect on NF-kB-dependent genes or inflammatory response of endothelial cells.
|Auxiliary resources (full texts, presentations, posters, etc.)|
Presentation: Invited oral at Nano-Biotechnologia PL, by Ewa Stępień
See On-line Journal of Nano-Biotechnologia PL
Submitted: 2012-07-18 11:13 Revised: 2012-07-18 11:13