Proteomic Profiling for In Situ Exposure in a Sentinel Freshwater Species to Describe the Crustacean Reproductive Effects of Aquatic Contamination

Abstract Complex mixtures of contaminants can affect aquatic organisms through diverse modes of action, making extrapolations of laboratory findings to field conditions complex. Here, we show that proteomics combined with active biomonitoring may inform about reprotoxic effects in the sentinel species Gammarus fossarum. Proteomic responses provide information on the diversity of underlying mechanisms and may serve as a sensitive early warning signal of reprotoxicity. Females were exposed in situ in 18 French surveillance sites and analyzed for reproductive end points and proteomic levels in the caeca and the ovaries. This study aimed to assess links between reproductive impairment and molecular responses, using the complementary information provided by both tissues. Protein coexpression analysis identified protein clusters associated with organ functions, reproductive impairments, or field exposure. Several modules were significantly associated with field condition or females’ physiological integrity. Interestingly, we identified a large diversity of biological pathways modulated in impacted females exposed to reprotoxic sites, with reproduction-related proteins as potential early biomarkers of reprotoxicity. These results highlight the relevance of considering field conditions and individual physiology within the eco-exposome framework and demonstrate the value of integrating omics and active biomonitoring to uncover diverse molecular signature behind field-induced reprotoxicity in this sentinel species.