Sea urchin embryos are highly sensitive to several kinds of stressors, and able to activatedifferent defense strategies. Gadolinium (Gd) is a metal of the lanthanide series of the elements:its chelates are employed as contrast agents for magnetic resonance imaging sincethe 1980s. Gd complexes are released in the aquatic environment, making Gd an emergentenvironmental pollutant. In this study we focused on the effects of Gd ions on sea urchinembryos development. The study was conducted looking at three different processes: generaldevelopment, apoptosis and autophagy. At the whole morphological level, Paracentrotus lividussea urchin embryos continuously exposed to Gd ions displayed morphological abnormalitiesand a significant inhibition of skeleton elongation and patterning. The study of apoptosisperformed by immunofluorescence (IF) staining using an anti-cleaved-caspase-3 antibody onwhole-mount embryos after 24h (gastrula) and 48h (pluteus) exposure showed no apoptoticinduction. Autophagic processes were investigated by Western blot analysis of total lysatesand IF staining (autophagosomes) on whole-mount embryos to detect LC3 protein andacridine orange (AO) vital staining to highlight the presence of acidic vesicular organelles(autophagolysosomes) in whole embryos. In particular, Western blots of embryos exposed to Gdshowed a 2.6-fold increase relative to controls at 24h and a 4-fold increase at 48h, suggesting thatthe autophagic process is acting as a cell survival strategy to defend the developmental program.In agreement, AO vital staining and LC3 IF confirmed an increased number of autophagosomesand autophagolysosomes. Taken together, results show that autophagy is a molecular processactivated in sea urchin embryos exposed to Gd ions.Work supported by University of Palermo FFR to MCR and partially by PO-FESR 2007-2013DeCroMed Project to VM. Authors thank Mr. M. Biondo for technical assistance.
|Number of pages||1|
|Publication status||Published - 2014|