Biological systems interact with environmental chemicals in complex ways and biochemical markers (biomarkers) often provide informative information on both extent of toxicity and biochemical toxicity mechanisms. In aquatic toxicology, it is common to use bivalve species as sentinels in marine and estuarine contexts and Daphnia as a sentinel in freshwater. We have applied redox proteomics as a means of assessing environmental stress in aquatic environmental contexts for many years1.Nanomaterials represent a novel category of environmental chemicals which pose unusual questions to the toxicologist2. What is meant by dose? Are particles taken up by organisms and can we follow their fate in multi-organ organisms? What aspects of the nanomaterial's structure and chemistry impacts on toxicity? In particular, a key unanswered question is how does the context of nanoparticle exposure influence toxicity? In aquatic systems there is scope for particles to agglomerate, dissolve or otherwise interact with the aquatic or sediment surrounding them. This talk focuses on three experiments in our lab in which well-characterised, engineered metal or metal oxide nanoparticles were exposed to test organisms: 1) the bivalve Mytilus edulis3; 2) the water-flea Daphnia magna4 and 3) cultured human astrocyte cells. Our approach is to expose to doses of nanoparticles and to identify redox proteomics targets which then yields insights to likely biochemical consequences of these nanoparticles. We have developed a toolkit of gel-based and gel-free approaches for identifying and enriching for proteins yielding insights in particular to their carbonylation or thiol oxidation1,5. The proteome seems to adapt quite quickly and in a dose-related manner to challenge by certain metal oxide nanoparticles in terms either of change of protein abundance or change in protein oxidative status. These effects are also somewhat species-specific.McDonagh, B. and Sheehan, D. (2007) Effect of oxidative stress on protein thiols in the blue mussel, Mytilus edulis: Proteomic identification of target proteins. Proteomics, 7 , 3395-3403.Tedesco, S. & Sheehan D. (2010) Nanomaterials as emerging environmental threats. Current Chemical Biology 4 , 151-160.Hu, W., Culloty, S., Darmody, G., Lynch, S., Davenport, J., Ramirez-Garcia, S., Dawson, K.A., Lynch, I., Blasco, J., Sheehan, D.(2014) Toxicity of copper oxide nanoparticles in the blue mussel, Mytilus edulis. Chemosphere. IN PRESSRainville L.-C., Carolan D, Varela, A.C., Doyle, H., Sheehan, D. (2014) Proteomic evaluation of citrate-coated silver nanoparticles toxicity in Daphnia magna. The Analyst 139 , 1678-1686.  Sheehan D., McDonagh, B., and Barcena A. (2010) Redox proteomics. Expert Reviews in Proteomics 7 , 1-4.

Effects of engineered metal and metal oxide nanoparticles on model aquatic organisms: Finding protein targets by redox proteomics

248th National Meeting (2014)

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