Genome-wide transcriptional profiling of C. elegans in a heavy metal contaminated soil after nZVI treatment

Classical ecotoxicological test and high-throughput molecular tools (microarray) were conducted on C. elegans to assess the effectiveness and ecosafety of a nanoremediation strategy applied to a highly polluted soil environment with heavy metals (HMs). We stablished a profiled gene expression in C. elegans exposed to the polluted soil, treated and untreated with nZVI. The results obtained showed that the percentage of differentially expressed genes decreased with the exposure time to nZVI. The expression profile of genes associated with stress response, metal toxicity, proteolysis, immune response, and cuticle development resulted affected. At short term, when a more effective HMs immobilization has occurred genes related to specific heavy metal detoxification mechanisms or to response to metal stress, were down regulated. After longer exposure time, we found decreased effectiveness of nZVI and increased HMs toxicity, whereas the transcriptional oxidative and metal-induced responses were attenuated. For each experimental condition (control and nZVI-treated soil, at three different sampling times), three microarray experiments corresponding to three independent RNA from the collected nematodes were processed and analyzed. The samples were processed with GeneChip® WT PLUS Reagent Kit (Applied Biosystems), hybridized with GeneChip™ C. elegans Gene 1.0 ST Arrays (Applied Biosystems) and scanned with a GeneChip® Scanner 3000 7G (Applied Biosystems).