Browsing by Author "Pereira, Joana FS"
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- Titanium Dioxide Nanoparticles molecular effects: Internalization in the Human Intestinal EpitheliumPublication . Rolo, Dora; Pereira, Joana FS; Matos, Paulo; Gonçalves, Lídia; Bettencourt, Ana Francisca; Jordan, Peter; Silva, Maria João; Louro, HenriquetaThe use of titanium dioxide nanoparticles (TiO2-NPs) as food additive and in food packaging demands a thorough assessment of their potential risk for human health, specifically with regard to gastrointestinal tract. Using intestinal cells, we analyzed the mechanisms by which digested TiO2-NPs (NM-102, NM-103 and NM-105, JRC repository) translocate through the intestinal epithelium layer, as compared to non-digested particles. Human digestion of TiO2-NPs was simulated using the INFOGEST in vitro harmonized digestion method. Caco-2 cells were grown as polarized cell monolayer for exposure and differentiation was evaluated by TEER. The translocation of TiO2-NPs, tagged with alizarin red, through the cell barrier was analysed by confocal microscopy, using colocalization with antibodies against specific endosomal compartments. The internalization of the TiO2-NPs was confirmed for the three TiO2-NPs tested, both before and after digestion simulation. The smallest TiO2-NPs were internalized into EEA1-positive early- endosomes and accumulated in late endosomes (Rab7), with only a small fraction following the degradative pathway to the lysosome (LAMP1). The data suggested that at least part of the TiO2-NPs could be redirected to the secretory pathway. Consistently, fluorescence passing from the apical to the basolateral chamber was observed, without disruption of the intestinal barrier function. The changes in cell function or signal transduction pathways are being studied and possible consequences to human gastrointestinal tract arediscussed. We thank the support from P. Alvito, C. Martins and R. Assunção (INSA,Lisbon, Portugal).