Evaluation of Nanoplastics Toxicity in Soil Nematode Caenorhabditis elegans by iTRAQ-Based Quantitative Proteomics

Plastic pollution is recognized as a major threat to ecosystems in 21 st century. Large plastic objects can undergo biotic and abiotic degradation to generate more toxic micro/nano-sized plastic pieces. Though tremendous efforts were made to evaluate adverse effects of microplastics, a comprehensive understanding of nanoplastics toxicity is still lacking, especially at the protein level. In the present study, using soil nematode Caenorhabditis elegans as in vivo model, we applied iTARQ-based quantitative proteomics to investigate proteome dynamics in response to exposure of 100 nm polystyrene nanoplastics. This study demonstrates overall disruption of proteome homeostasis as a biological consequence of nanoplastics deposition. After 48-hour exposure to 0.1, 1, and 10 mg/L nanoplastics, 136 out of 1684 proteins expressed differentially and 108 proteins were up-regulated. These proteins were related to ribosome biogenesis, translation, proteolysis, protein processing in endoplasmic reticulum, and energy metabolism. Remarkably, proteome dynamics in response to polystyrene nanoplastics could interpret the phenotypic defects of nematodes at molecular level. To the best of our knowledge, this is the first study applying proteomics to investigate nanoplastic toxicity and stress response in terrestrial organisms, which is promising to provide deeper insight into the molecular mechanisms underlying toxicology of nanoplastics.