Gender differences in protein expression after polystyrene nanoplastics exposure in mussels Mytilus galloprovincialis

Plastic pollution is a significant issue that the scientific community has been actively studying due to its harmful effects on aquatic ecosystems. Nanoplastics can pass through cellular barriers and enter the mussel's bloodstream. More worryingly, they can also penetrate sperm cells and oocytes, potentially impacting their motility and resilience. Reproductive success drives a shift in population dynamics and plays a vital role in maintaining a healthy ecosystem. Proteomics helps detect protein changes caused by exposure to contaminants, such as nanoplastics, in marine organisms, providing deeper molecular-level insights into contamination-induced cellular pathways. Therefore, this study aimed to utilise a high-throughput proteomic approach to evaluate the impact of polystyrene nanoplastics (PS-NPs) on the gonads of male and female M. galloprovincialis, using a SWATH-MS analysis after 21 days of exposure to 10 μg/L of PS-NPs (50 nm). The accumulation of PS-NPs was also evaluated in male and female mussels. A comparison in protein expression of controls vs. those exposed in male and female mussel gonads and between males and females was evaluated. The findings indicate that PS-NP accumulation in male gonads alters protein expression more significantly than in females, interfering with protein synthesis, energy production, intracellular transport, and cellular homeostasis, and possibly impaired reproductive function. Female gonads exposed to PS-NPs revealed disruption in proteins associated with translation, RNA processing and signaling, ribosome biogenesis, cell cycle regulation, and stress response. Protein folding, lipid metabolism, and calcium signaling pathways were also affected, leading to oogenesis, meiotic progression, intracellular transport, and energy metabolism impairments. These disruptions ultimately impact reproductive success and cellular homeostasis, leading to a decline in biodiversity.