Do small things lead to big problems? Mechanisms of uptake and toxicity of metal nanoparticles in intestinal cells (NanoTraffic). Dr. Matteo Minghetti. PEOPLE MARIE CURIE ACTIONS Intra-European Fellowships.
Using models of human and fish intestinal and hepatic cells this project aims at investigating subtoxic intracellular effects of metal (Ag- and TiO2-) NPs. To mimic more closely the in vivo scenario and allow cell polarization, intestinal cells are grown on transwells. Moreover, to evaluate the effect of metal-NPs following the intestinal uptake and metabolism, hepatic cells are co-cultured in the sub located well. This system allows the measurement of NP transport across polarized intestinal cells and at the same time the measurement of cellular and molecular effects. Particular emphasis is placed on lysosome function and disturbance of the homeostasis of essential elements such as iron, zinc and copper. Tight regulation of the homeostasis of essential elements is essential for the life of all living organisms. Several metal specific transporter proteins are involved to allow this process. In this study the function of a copper ATPase, that are known to transport silver as well as copper, is investigated. The impact of how metal and nano-metals interact with other metals and metalloids is poorly understood at the molecular level. My research is providing new evidence that silver in its ionic and nano-form is affecting the homeostasis of some essential metals.
The EU FP7 Project NanoValid (contract: 263147, www.nanovalid.eu) aims to develop new reference methods and certified reference materials for hazard identification, risk assessment and life cycle assessment (LCA) of engineered nanomaterials (ENMs). Our project is focused on the ecotoxicological effects of ENMs especially considering the aquatic environment. Cell lines from rainbow trout (Oncorhynchus mykiss) will be used to assess the ecotoxicological effects of ENMs to fish. Currently, a novel two-compartment intestinal barrier model is developed using the rainbow trout intestinal cell line RTgutGC to investigate the toxicity and translocation of ENMs in fish intestinal epithelium. Initial results show that nanoparticles can cause toxicity to the cells and can also be translocated across the intestinal barrier – either as intact particles or as dissolved species released from the particles. Taken together, these studies should yield valuable information of the effects of ENMs to aquatic organisms especially on the molecular and cellular level (Dr. M. Geppert).
In the MeNanoqa project (SNSF, NRP 64) aims at examining the toxicity mechanisms and uptake of AgNP on rainbow trout fish cell line (RTgill-W1). Main results show that AgNP toxicity depends on the composition of exposure media. AgNP concentration-response curves as a function of dissolved silver ions, and the limited prevention of toxicity by silver ligands, indicate that AgNP elicit a particle-specific effect on the cells. Electronic microscopy and ICP-MS results indicate that AgNP can be internalized in RTgill-W1 cells where they accumulate in endocytosis related cell organelles. Isolation and analysis of the accumulated AgNP show particles to be coated with various proteins that were identified by mass spectrometry. Analysis of the biochemical function of these proteins allow to link observed cytotoxic effects of the AgNP to initial mechanisms of toxicity (PhD thesis Y. Yue).