Vanadium perturbs the fertilization outcome and the metalloproteinase activity in sea urchin embryos

Metal toxicology represents a current major topic due to the disper- sion of these elements in the environment. Metals are released from both natural sources and industrial activities. Some of them have also a clinical interest due to their application as metallodrugs (i.e., Pt, Cu, Au, Ru, and Y) or in medical diagnosis (Gd).1,2 Recently, V derivatives are considered as potential therapeutic factors in some diseases (e.g., obesity, diabetes, cancer, neurodegenerative and heart disorders). As a consequence, pharmaceutical residues could repre- sent emerging pollutants of aquatic environments, as wastewater treatment plants do not sufficiently remove these compounds3. Embryonic models represent an adequate system for testing metal toxicity as they are sensitive to these elements. Here, we analysed the effects of different V concentrations, from very cytotoxic (1mM) to environmentally relevant doses (50nM), using two approaches: the fertilization test (FT) and the metalloproteinase (MMPs) activity.4 We observed that V affected, in a dose-dependent manner, the percentage of fertilization and increased abnormalities regarding the egg and/or the fertilization membrane morphology. MMPs could represent another marker of V toxicity since it gener- ates a cellular imbalance of metal ions. This would disturb the cat- alytic mechanism of these enzymes as they require ions as cofac- tors. Therefore, their dysfunction could represent a biomarker of metal-induced damage. We observed a total of 9 MMPs. Those with high molecular weight (from 309 to 59kDa) seemed to be mainly induced by elevated V concentrations (1mM, 500µM and 100µM). Conversely, low molecular weight MMPs (from 34 to 22kDa) appeared to be completely inhibited by these high V doses. On the other hand, lower V concentrations seemed to be more tolerated as there were no significant differences compared to control. In con- clusion, FT and MMP activity could represent a reliable method to test V toxicity, using the sea urchin as a sensitive model system.