Role of endocytotic uptake routes in impacting the ROS-related toxicity of silver nanoparticles to Mytilus galloprovincialis: a redox proteomic investigation

Oxidative stress is often implicated in nanoparticle toxicity. Several studies have highlighted the role of internalization routes in determining nanotoxicity. Here, we investigate how two endocytotic mechanisms (clathrin- and caveolae-mediated) impact on redox balance in gill and digestive gland of the mussel, Mytilus galloprovincialis. Animals were exposed (for 3, 6 and 12 h) to two sizes of silver nanoparticles (AgNP: <50 nm and <100 nm) prior to and after blockade of two endocytic pathways (amantadine blocks clathrin-mediated endocytosis while nystatin blocks caveolae-mediated endocytosis). Redox-proteomic tools were used to determine effects. Our results demonstrate the ability of both sizes of AgNP (<50 and <100 nm) to cause protein thiol oxidation and/or protein carbonylation. However, blockade of endocytotic routes mitigated AgNP toxicity. Differential ROS-related toxicity of AgNP to mussel tissues seemed to be linked to tissue-specific mode of action requirements. Cell uptake mechanism strongly influences toxicity of AgNPs in this filter-feeder

Contribution a l'amelioration qualitative et quantitative des images de medecine nucleaire en tomographie d'emission a simple photon

SIGLECNRS T Bordereau / INIST-CNRS - Institut de l'Information Scientifique et TechniqueFRFranc

Redox proteomic insights into involvement of clathrin-mediated endocytosis in silver nanoparticles toxicity to Mytilus galloprovincialis.

Clathrin-mediated endocytosis is a major mode of nanoparticle (NP) internalization into cells. However, influence of internalization routes on nanoparticle toxicity is poorly understood. Here, we assess the impact of blocking clathrin-mediated endocytosis upon silver NP (AgNP) toxicity to gills and digestive glands of the mussel Mytilusgalloprovincialisusing the uptake inhibitor, amantadine. Animals were exposed for 12h to AgNP (< 50 nm) in the presence and absence of amantadine. Labeling of oxidative protein modifications, either thiol oxidation, carbonyl formation or both in two-dimensional electrophoresis separations revealed 16 differentially affected abundance spots. Amongst these, twelve hypothetical proteins were successfully identified by peptide mass fingerprinting (MALDI TOF-MS/MS). The proteins identified are involved in buffering redox status or in cytoprotection. We conclude that blockade of clathrin-mediated endocytosis protected against NP toxicity, suggesting this uptake pathway facilitates toxicity. Lysosomal degradation and autophagy are major mechanisms that might be induced to mitigate NP toxicity

Histopathology and analyses of inflammation intensity in the gills of mussels exposed to silver nanoparticles: role of nanoparticle size, exposure time, and uptake pathways

<p>Environmentally induced perturbation of health parameters lead to morphological changes associated to the inflammatory response. Hematoxyline and eosin (H&E)-stained gill filaments sections were examined for such changes and inflammation intensity was scored according to a quantitative model in order to evaluate the health status of <i>in vivo</i> exposed (for 3, 6, and 12 h) mussels to silver nanoparticles (Ag-NPs <50 nm and Ag-NPs <100 nm) prior and after the inhibition of two potential uptake pathways (clathrin- and caveolae-mediated endocytosis) with the aid of pharmaceutical inhibitors (amantadine and nystatin). The impacts of the nanoparticles (NPs) size, as well as their uptake routes within different time of exposure on the inflammatory response were assessed. The results showed that Ag-NPs clearly induced morphological changes associated to the inflammatory response in gill tissues (Mann–Whitney <i>p</i> values were <.05). It is also clear that the length of the exposure as well as the NP size highly impacted inflammation intensity (highest histopathological indices recorded with Ag-NPs <100 nm). Also, the routes of NPs entry noticed to be major factor underlying inflammatory response (significant inflammation intensity reported with Ag-NPs <50 nm after blockade of uptake routes; <i>p</i> <.05). Throughout, it was concluded that inflammation intensity was related to NPs size and exposure time. Overall, uptake routes are shown to be the major factor underlying nanotoxicity.</p

Synthesis of 3,4-dihydropyrimidin-2(1H)-ones/thiones via Biginelli reaction promoted by bismuth(III)nitrate or PPh3 without solvent

3,4-Dihydropyrimidinones/thiones and their derivatives are synthesized via Biginelli routes involving an aldehyde, 1,3-dicarbonyl compound and urea or thiourea. Use of catalysts such as bismuth nitrate in acetonitrile or PPh3 without solvent lead to higher yields compared to the classic method using HCl in ethanol. In such way, 3,4-dihydropyrimidinones which are hardly prepared under classic conditions can be synthesized with fair yields