The TLR4/NFκB-Dependent Inflammatory Response Activated by LPS Is Inhibited in Human Macrophages Pre-Exposed to Amorphous Silica Nanoparticles

Amorphous silica nanoparticles (ASNP) are present in a variety of products and their biological effects are actively investigated. Although several studies have documented pro-inflammatory effects of ASNP, the possibility that they also modify the response of innate immunity cells to natural activators has not been thoroughly investigated. Here, we study the effects of pyrogenic ASNP on the LPS-dependent activation of human macrophages differentiated from peripheral blood monocytes. In macrophages, 24 h of pre-exposure to non-cytotoxic doses of ASNP markedly inhibited the LPS-dependent induction of pro-inflammatory (TNFα, IL-6) and anti-inflammatory cytokines (IL-10). The inhibitory effect was associated with the suppression of NFκB activation and the increased intracellular sequestration of the TLR4 receptor. The late induction of glutamine synthetase (GS) by LPS was also prevented by pre-exposure to ASNP, while GS silencing did not interfere with cytokine secretion. It is concluded that (i) macrophages exposed to ASNP are less sensitive to LPS-dependent activation and (ii) GS induction by LPS is likely secondary to the stimulation of cytokine secretion. The observed interference with LPS effects may point to a dampening of the acute inflammatory response after exposure to ASNP in humans

CyTest – An Innovative Open-source Platform for Training and Testing in Cythopathology

Abstract This paper describes an e-learning platform developed in the context of the European Project CyTest (2014-1-IT01-KA202-002607), dedicated to Cytological Training at European Standard through Telepathology. The main, and novel, feature of our system is the deep integration between virtual microscopy and the training system: images are not simply there to be seen but they are active parts of testing, supporting quantitative measurement of image comprehension, for instance by evaluating the identification of relevant cellular structures by the position of markers put by the student on the image. The solution we developed offers a complete tool for easy creation and interactive access to questions related to images and fully integrates the components of virtual microscopy and teaching, based on state-of-the-art instruments for digital pathology images management, as OMERO, and for training course distribution, as Moodle. The system can be easily extended to support histopathological diagnosis. The software is distributed as Open Source and available on GitHub

An in vitro strategy to assess mitigation of hazardous properties of engineered metal nanoparticles

The huge progress in the nanotechnology field has requested the production of increasingly advanced engineered nanoparticles (NPs). In particular, metal-based advanced NPs are widely used in several industrial applications. However, their potential effects on human health during occupational exposure are still incompletely characterized thus far and possible strategies to decrease their hazardous properties are not yet clearly defined. In this project we are developing an in vitro approach to test the cytotoxic effects of metal-based NPs, as derived from production lines or modified through coating with organic or inorganic moieties. We have used two cell models widely employed in toxicological studies, the human alveolar cell line A549 and the murine macrophage cell line RAW264.7, to avoid possible limitations due to cell specific effects. Moreover, in order to evaluate the effectiveness of mitigation approaches for NPs endowed with little acute cytotoxicity, additional endpoints, alternative to viability, have also been assessed. Colloidal suspensions of Ag, TiO2 and ZrO2 NPs were tested as provided by industries or modified with SiO2 NPs or citrate used as coating remediation agents. Heterocoagulation of opposite charged phases was applied in order to promote the coating of pristine surfaces by modifying agents. Heterocoagulated sols were obtained by ball milling sols of positive charged Ag, TiO2 and ZrO2 NPs with negative charged SiO2 NPs or citrate ions. Modified samples, obtained by spray-drying and re- dispersing in water the corresponding sols, were also obtained in order to compare reactivity. Original and modified NPs were added to culture media starting from water colloidal suspensions. Viability was determined with the resazurin method in a range of doses from 2.5 to 80 nfg/cm2 (0.3125 to 20 g/cm2 for Ag NPs) of monolayer surface at three experimental times (24, 48 and 72h). The expression of the inducible form of nitric oxide synthase (Nos2), an indicator of macrophage activation and, hence, of pro-inflammatory activity, was assessed with RT-PCR as an end-point alternative to viability. Among the NPs tested, only Ag NP caused a significant loss of viability, with an IC50 of about 0.8 g/cm2 for Raw264.7 cells and 2.4 g/cm2 for A549 cells at the 24h-experimental time. In a preliminary experiment, SiO2 NPs were demonstrated to have no significant effect on cell viability. The comparison between original and SiO2-coated Ag NPs, performed in the same experiment, suggested a coating-independent mitigation effect of bioreactivity exerted by the spray drying procedure. However, once corrected for the actual Ag content of the spray- dried powder, no significant difference was found in the IC50 values, indicating that neither silica coating nor spray drying mitigate cytotoxicity. The effects on viability of original TiO2 and ZrO2 NPs were assessed using P25 Aeroxide TiO2 NPs as a reference material. These materials did not affect significantly cell viability at any time point tested, so that it was not possible to estimate IC50 values for either cell line. However, titania produced a clear-cut induction of Nos2 expression in Raw264.7 cells, thus indicating their potential pro- inflammatory activity. Citrate coating did not produce any significant attenuation of the biological effect. In summary, these preliminary results showed no mitigating effect of the surface modifications tested on the biological effects of the engineered NPs investigated. However, the exploitation of this in vitro experimental strategy can be useful for the preliminary assessment of the mitigation potential of surface modifications of both low-toxic and high-toxic engineered NPs. Supported by EU Grant NMP4-SL-2012-280716 (Sanowork Project