Sea urchin embryos as an in vivo model for the assessment of manganese toxicity: developmental and stress response effects

Abstract

In the marine environment increasing concentrations of bio-available compounds often result from anthropogenic activities. Among metal ions, manganese represents a new emergent factor in environmental contamination. Here, we studied the effects of manganese on Paracentrotus lividus sea urchin embryos using biological and biochemical approaches for the analysis of impact on development, tissue accumulation and stress markers. Embryos were continuously exposed from fertilization to manganese at concentrations ranging from 1.0 to 61.6 mg l(-1), monitored for developmental abnormalities at 48 h after fertilization, and used for atomic spectrometric analysis at various times from 6 to 72 h. We found that concentration- and time-dependent increases in morphological abnormalities were directly correlated to manganese accumulation, with major defects in skeleton formation at 48 h. Concurrently, we found an upregulation of the hsc70 and hsc60 stress proteins detected by immunoblotting, whereas no induction of apoptosis or ROS production was observed by TUNEL and live tests, respectively. Taken together, our findings demonstrate that the observed manganese embryo-toxicity is related to both its intracellular accumulation and misregulated homeostasis, and confirm the importance of stress proteins as protective agents in the acquisition of tolerance and resistance to apoptosis.

Manganese overload affects p38 MAPK phosphorylation and metalloproteinase activity during sea urchin embryonic development

“…We demonstrated that embryos showed an elevated tolerance/resistance to Mn, as they accumulated high amounts into cells in a time-and concentration-dependent manner without producing lethal effects. Rather, we observed a concentration-dependent increase in the number of morphological abnormalities and in the levels of the hsc70 and hsc60 proteins (Pinsino et al, 2010). In addition, we found that the exposure to the highest Mn concentration tested (61.6 mg l À1 or 1.12 mM) prevents skeleton growth which result in spicule-lacking embryos, interferes with calcium uptake and internalization into cells, and causes remarkable consequences in skeletogenic gene expression and ERK mediated signaling pathway (Pinsino et al, 2011).…”

“…We found that P. lividus embryos accumulate high amounts of Mn in a concentration-and time-dependent manner. Its accumulation was also directly correlated with a concentration-dependent increase in the number of morphological abnormalities (Pinsino et al, 2010). As the highest Mn concentration used (61.6 mg l…”

“…In one of our previous studies we investigated the biological effects of exposure to increasing concentrations of Mn on P. lividus embryo development (from 1.0 to 61.6 mg l À1 ) according to classical toxicological criteria: concentration-and time-dependent responses, analysis of impact on development, Mn accumulation (Pinsino et al, 2010). We found that P. lividus embryos accumulate high amounts of Mn in a concentration-and time-dependent manner.…”

“…Embryos were cultured as described previously (Pinsino et al, 2010). Treatment with manganese (Mn) was carried out by culturing embryos in 1.12 mM MnCl 2 (SIGMA) from fertilization until the pluteus stage.…”

Effects of exposure to gadolinium on the development of geographically and phylogenetically distant sea urchins species

“…We addressed this gap in knowledge in an investigation of the effects of Gd on the development of sea urchin embryos and larvae. The sea urchin embryo has long been an important model organism in developmental biology and eco-toxicology to assess the hazard posed by contaminants entering the marine environment (Radenac et al, 2001;Russo et al, 2003;Roccheri et al, 2004;Pinsino et al, 2010;Tellis et al, 2014). A wealth of research with sea urchin embryos and larvae have shown that chemical pollutants impair development and that the larval skeleton is a particularly vulnerable response variable for ecotoxicological tests (Bonaventura et al, 2015;Morroni et al, 2016).…”