The Enchytraeus crypticus stress metabolome - CuO NM case study

Area of Science:

• Environmental toxicology
• Metabolomics
• Nanomaterial safety assessment

Background:

• The stress metabolome offers insights into organismal responses to environmental stressors.
• Nanomaterials (NMs) require alternative hazard assessment methods.
• Understanding NM-organism interactions is crucial for environmental safety.

Purpose of the Study:

• To conduct the first metabolome profiling of Enchytraeus crypticus exposed to copper nanomaterials (CuO NM) and copper chloride (CuCl2).
• To investigate the time- and concentration-dependent effects of these copper forms on the organism's metabolome.
• To differentiate the toxicological mechanisms of CuO NM and CuCl2 based on metabolomic profiles.

Main Methods:

• High-performance liquid chromatography-mass spectrometry (HPLC-MS) was employed for metabolite profiling.
• Reversed-phase separation was used with positive and negative mode mass spectrometric detection.
• Exposure scenarios included time frames (0-14 days) and effect concentrations (EC10, EC50) for CuO NM and CuCl2.

Main Results:

• Metabolite profiling identified 155 and 382 metabolite features in positive and negative modes, respectively.
• Differentially expressed metabolites (DEMs) showed distinct patterns: decreasing with time for CuO NM, increasing for CuCl2 EC50.
• CuO NM exposure led to widespread down-regulation of DEMs (amino acids, lysophospholipids), while CuCl2 primarily up-regulated lipid metabolism-related metabolites.

Conclusions:

• Metabolomic profiles revealed distinct toxicity mechanisms for CuO NM and CuCl2.
• CuO NM toxicity involves neurotransmission, nucleic acid generation, cellular energy, and immune defense pathways.
• CuCl2 toxicity is mainly associated with lipid metabolism, differing from CuO NM.
• This study provides potential biomarkers for copper materials, aiding in risk assessment and safer-by-design strategies.