Multi-omics Analysis Uncovers Lifespan Effects of Polyethylene and Polystyrene Microplastics Coexposure in Drosophila melanogaster

<title>Abstract</title> Microplastics (MPs) are ubiquitous global contaminants, posing a long-term exposure risk to both the entire ecosystem and human health. Although increasing researches have indicated that individual MPs generally exhibit biotoxicity, the combined effects of multiple MPs exposure on biological lifespan and the mechanisms involved remain largely unrevealed. Here we employed <italic>Drosophila melanogaster</italic>, subsequently referred to <italic>Drosophila</italic>, as a biological model to investigate the impact of polyethylene (PE, irregular shape, 14.55 ± 5.98 µm) and polystyrene (PS, sphere, 1.86 ± 0.89 µm) microplastics co-exposure on lifespan at both low concentrations (10 and 100 mg/L) and high concentrations (10, 20 and 50 g/L). Furthermore, we delved into the underlying mechanism through metabolomics and transcriptomics analysis. Our results demonstrated PE and PS MPs co-exposure with greatly high concentrations significantly reduced the lifespan of <italic>Drosophila</italic> and influenced age-related phenotypes such as climbing ability, intestinal barrier and hunger resistance. We found that differential metabolites were engaged in various metabolic pathways, including ABC transporters, alanine, aspartate and glutamate metabolism. Differentially expressed genes (DEGs) were closely related to Toll and Imd signaling pathway and Longevity regulating pathway. A combined metabolomics and transcriptomics analysis revealed that PE and PS MPs co-exposure induced alterations in gene expression and metabolites related to the immune system and energy metabolism, thereby affecting <italic>Drosophila</italic> lifespan. The findings provided a mechanistic understanding for the effects of PE and PS MPs co-exposure on <italic>Drosophila’s</italic> lifespan.