Membrane interaction of pegylated superparamagnetic nanoparticles

Iron oxide core-shell nanoparticles are gaining ever increasing interest for separation and imaging in biotechnology and biomedicine1,2, due to supposed low cytotoxicity and their superparamagnetic properties. Hydrophilic polymer-coated nanoparticles are believed to have low nonspecific interactions in biological systems, but much additional work in-vitro and in-vivo is needed to understand their detailed interactions with proteins, membranes and cells. We investigated monodisperse (SD\u3c5%), single-crystalline and superparamagnetic magnetite nanoparticles of different core size and densely grafted with poly(ethylene glycol) (Mw=5kDa), with particular emphasis on their interaction with biological membranes. Membrane interactions will determine nonspecific recognition and uptake by cells. These nanoparticles demonstrated no cytotoxicity and low cell uptake in in-vitro culture of HeLa and HEK cell lines. However, using Quartz Crystal Microbalance (QCM) a strong DLVO-type interaction could be demonstrated with anionic membranes that simulate eukaryote membranes. This interaction was only present in nonphysiological buffer with low ionic strength. Only low, weak and transient binding was observed to zwiterionic phosphocholine membranes. Core size seems to have an effect, with the smallest core size (3.3nm) yielding the strongest interactions while 8nm cores displayed almost no interaction. These results imply that dense polymer grafting and nanoparticle curvature are crucial parameters to control interactions between biomedical core-shell nanoparticles and their biomolecular environment, in particular cell membranes. The interaction between nanoparticle and membrane was furthermore shown to not perturb membrane structure by Differential Scanning Calorimetry (DSC). Please click Additional Files below to see the full abstract

Data Analysis : Morphometric signatures of endocrine disrupting chemicals exposures in zebrafish eleutheroembryos [Dataset]

Understanding the mode of action of the different pollutants in human and wildlife health is a key step in environmental risk assessment. The aim of this study was to determine signatures that could link morphological phenotypes to the toxicity mechanisms of four Endocrine Disrupting Chemicals (EDCs): bisphenol A (BPA), perfluorooctanesulfonate potassium salt (PFOS), tributyltin chloride (TBT), and 17-ß-estradiol (E2). Zebrafish (Danio rerio) eleutheroembryos were exposed from 2 to 5 dpf to a wide range of BPA, PFOS, TBT and E2 concentrations. At the end of the exposures several morphometric features were assessed. Common and non-specific effects on larvae pigmentation or swim bladder area were observed after exposures to all compounds. BPA specifically induced yolk sac malabsorption syndrome and altered craniofacial parameters, whereas PFOS had specific effects on the notochord formation presenting higher rates of scoliosis and kyphosis. The main effect of E2 was an increase in the body length of the exposed eleutheroembryos. In the case of TBT, main alterations on the morphological traits were related to developmental delays. When integrating all morphometrical parameters, BPA showed the highest rates of malformations in terms of equilethality, followed by PFOS and, distantly, by TBT and E2. In the case of BPA and PFOS, we were able to relate our results with effects on the transcriptome and metabolome, previously reported. We propose that methodized morphometric analyses in zebrafish embryo model can be used as an inexpensive and easy screening tool to predict modes of action of a wide-range number of contaminants.This work was supported by a grant from the Spanish Ministry of Economy and Competitiveness (ref. CTQ2014-56777-R). LNM was supported by a H2020-Marie Skłodowska-Curie Action MSCA-IF-RI-2017 awarded by the European Commission (ref.797725 EpiSTOX). RM was supported by an FPU predoctoral fellow from the Spanish Ministry of Education and Science (ref. FPU15/03332). We thank Morgane Van Antro and Chiara Luccarelli for helping with eleutheroembryos measurements.Peer reviewe

Morphometric signatures of exposure to endocrine disrupting chemicals in zebrafish eleutheroembryos

Understanding the mode of action of the different pollutants in human and wildlife health is a key step in environmental risk assessment. The aim of this study was to determine signatures that could link morphological phenotypes to the toxicity mechanisms of four Endocrine Disrupting Chemicals (EDCs): bisphenol A (BPA), perfluorooctanesulfonate potassium salt (PFOS), tributyltin chloride (TBT), and 17-ß-estradiol (E2). Zebrafish (Danio rerio) eleutheroembryos were exposed from 2 to 5 dpf to a wide range of BPA, PFOS, TBT and E2 concentrations. At the end of the exposures several morphometric features were assessed. Common and non-specific effects on larvae pigmentation or swim bladder area were observed after exposures to all compounds. BPA specifically induced yolk sac malabsorption syndrome and altered craniofacial parameters, whereas PFOS had specific effects on the notochord formation presenting higher rates of scoliosis and kyphosis. The main effect of E2 was an increase in the body length of the exposed eleutheroembryos. In the case of TBT, main alterations on the morphological traits were related to developmental delays. When integrating all morphometrical parameters, BPA showed the highest rates of malformations in terms of equilethality, followed by PFOS and, distantly, by TBT and E2. In the case of BPA and PFOS, we were able to relate our results with effects on the transcriptome and metabolome, previously reported. We propose that methodized morphometric analyses in zebrafish embryo model can be used as an inexpensive and easy screening tool to predict modes of action of a wide-range number of contaminants.This work was supported by a grant from the Spanish Ministry of Economy and Competitiveness (ref. CTQ2014-56777-R). LNM was supported by a H2020-Marie Skłodowska-Curie Action MSCA-IF-RI-2017 awarded by the European Commission (ref. 797725-EpiSTOX). RM was supported by an FPU predoctoral fellow from the Spanish Ministry of Education and Science (ref. FPU15/03332). We thank Chiara Luccarelli for helping with eleutheroembryos measurements.Peer reviewe

Dose-dependent transcriptomic responses of zebrafish eleutheroembryos to Bisphenol A

Despite the abundant literature on the adverse effects of Bisphenol A (BPA) as endocrine disruptor, its toxicity mechanisms are still poorly understood. We present here a study of its effects on the zebrafish eleutheroembryo transcriptome at concentrations ranging from 0.1 to 4 mg L−1, this latter representing the lowest observed effect concentration (LOEC) found in our study at three different macroscopical endpoints (survival, hatching and swim bladder inflation). Multivariate data analysis methods identified both monotonic and bi-phasic patterns of dose-dependent responses. Functional analyses of genes affected by BPA exposure suggest an interaction of BPA with different signaling pathways, being the estrogenic and retinoid receptors two likely targets. In addition, we identified an apparently unrelated inhibitory effect on, among others, visual function genes. We interpret our data as the result of a sum of underlying, independent molecular mechanisms occurring simultaneously at the exposed animals, well below the macroscopic LOEC, but related to at least some of the observed morphological alterations, particularly in eye size and yolk sac resorption. Our data supports the idea that the physiological effects of BPA cannot be only explained by its rather weak interaction with the estrogen receptor, and that multivariate analyses are required to analyze the effects of toxicants like BPA, which interact with different cellular targets producing complex phenotypes. Estrogenic- and retinoid-like transcriptomic effects of bisphenol A in zebrafish eleutheroembryos and their relationship with morphological alterations. © 2018 Elsevier LtdThis work was supported by the European Research Council under the European Union's Seventh Framework Programme ( FP/2007–2013 )/ERC Grant Agreement n. 320737 . Some part of this study was also supported by a grant from the Spanish Ministry of Economy and Competitiveness ( CTQ2014-56777-R ) and by a grant ( PT17/0009/0019 ) from ISCIII (Carlos III Health Institute), part of the Spanish Ministry of Economy and Competitiveness, and cofinanced by the European Regional Development Fund (ERDF). LNM was supported by a Beatriu de Pinos Postdoctoral Fellow ( 2013BP-B-00088 ) awarded by the Secretary for Universities and Research of the Ministry of Economy and Knowledge of the Government of Catalonia and the Cofund programme of the Marie Curie Actions of the 7th R&D Framework Programme of the European Union. RM was supported by a FPU predoctoral fellow from the Spanish Ministry of Education, Culture and Sport (ref. FPU15/03332 ). We would like to thank Ms. Elia Martinez-Prats and David Angelats for helping with the real time qRT-PCRs measurements. Appendix APeer reviewe

Interaction of Size-Tailored PEGylated Iron Oxide Nanoparticles with Lipid Membranes and Cells

Targeted nanomedicine builds on the concept that nanoparticles can be directed to specific tissues while remaining inert to others organs. Many studies have been performed on the synthesis and cellular interactions of core–shell nanoparticles, in which a functional inorganic core is coated with a biocompatible polymer layer that should reduce nonspecific uptake and cytotoxicity. However, work is lacking that relates structural parameters of the core–shell structure and colloidal properties directly to interactions with cell membranes and further correlates these interactions to cell uptake. We have synthesized monodisperse (SD < 10%), single-crystalline, and superparamagnetic iron oxide nanoparticles (SPION) of different core size (3–8 nm) that are densely grafted with nitrodopamine-poly­(ethylene glycol) (NDA-PEG­(5 kDa)) brushes. We investigated the interactions of the PEGylated SPION with biomimetic membranes and cancer and kidney cells. It is shown that a dense homogeneous PEG shell suppresses membrane interactions and cell uptake but that nanoparticle curvature can influence membrane interactions for similarly grafted nanoparticles. Weak adsorption to anionic lipid membranes is shown to correlate with eukaryote cell uptake and is attributed to double-layer interactions without direct membrane penetration. This attraction is strongly suppressed during physiological conditions and leads to unprecedented low cell uptake and full cell viability when compared to those of traditional dextran-coated SPION. Less curved (larger core) PEGylated SPION show weaker membrane adsorption and lower cell uptake due to effectively denser shells. These results provide a better understanding of design criteria for core–shell nanoparticles in terms of avoiding nonspecific uptake by cells, reducing toxicity, and increasing circulation time

Peer review of the pesticide risk assessment of the active substance glyphosate

Abstract The conclusions of EFSA following the peer review of the initial risk assessments carried out by the Assessment Group on Glyphosate (AGG), consisting of the competent authorities of France, the Netherlands, Sweden and Hungary, acting jointly as rapporteur Member State for the pesticide active substance glyphosate are reported. The context of the peer review was that required by Commission Implementing Regulation (EU) No 844/2012. The conclusions were reached on the basis of the evaluation of the representative uses of glyphosate as a herbicide as proposed by the applicants, covering uses pre‐sowing, pre‐planting and pre‐emergence plus post‐harvest in vegetables and sugar beet; post‐emergence of weeds in orchards, vineyards, row vegetables, railway tracks against emerged annual, biennial and perennial weeds. Moreover, uses as spot treatment against invasive species in agricultural and non‐agricultural areas, and in vegetables and sugar beet against couch grass are also included. The reliable endpoints, appropriate for use in regulatory risk assessment, are presented. Missing information identified as being required by the regulatory framework is listed. Concerns are reported where identified

Peer review of the pesticide risk assessment of the active substance Aspergillus flavus strain MUCL54911

Abstract The conclusions of the European Food Safety Authority (EFSA) following the peer review of the initial risk assessments carried out by the competent authority of the rapporteur Member State, Italy, for the pesticide active substance Aspergillus flavus strain MUCL54911 and the considerations as regards the inclusion of the substance in Annex IV of Regulation (EC) No 396/2005 are reported. The context of the peer review was that required by Regulation (EC) No 1107/2009 of the European Parliament and of the Council. The conclusions were reached on the basis of the evaluation of the representative use of Aspergillus flavus strain MUCL54911 as a biocontrol agent for reduction of aflatoxins contamination on maize (field application). The reliable endpoints, appropriate for use in regulatory risk assessment, are presented. Missing information identified as being required by the regulatory framework is listed. Concerns are identified