Hepatopancreatic proteomics reveals metabolic reprogramming associated with divergent thermal stress-response...

Thermal stress is a prevalent challenge in the aquaculture of aquatic species. To characterize the hepatopancreatic proteomic differences in Procambarus clarkii under stress conditions, we applied an iTRAQ-based quantitative proteomic assay to identify differentially abundant proteins (DAPs). This analysis was conducted on the hepatopancreas of crayfish exhibiting strong stress resistance (SSR), representing a sustained thermal stress-tolerance trajectory, and weak stress resistance (WSR), representing an early stress-intolerance trajectory. In total, 1198 proteins were quantified; 184 proteins were identified as having at least a 1.2-fold change in abundance and adjusted P-value (FDR) <0.05, with 102 upregulated and 82 downregulated in SSR relative to WSR. Upregulated proteins were predominantly enriched in translation and aromatic compound catabolic processes, as well as pathways such as ribosome, retinol metabolism, linoleic acid metabolism, hormone biosynthesis, and tryptophan metabolism. Conversely, downregulated proteins were mainly involved in fatty acid biosynthesis, vacuolar transport, signal transduction, ATP hydrolysis coupled proton transport processes, and with significant enrichment in pathways, including oxidative phosphorylation, NF-kappa B signaling pathway, and synaptic vesicle cycle pathways. A pathway-level comparison between the DAPs and previously identified differential metabolites revealed that pathways containing both altered proteins and metabolites were predominantly involved in proteostasis/stress response, energy metabolism, and glutathione metabolism. Transcript-level assessment of selected proteomic candidates showed consistent upregulation patterns for genes involved in energy metabolism (such as MDH), antioxidant factors (including sod), and consistent downregulation patterns of ER stress markers (such as GRP78). These results suggest that differences in protein abundance between WSR and SSR are associated with alterations in energy metabolism, antioxidant-related processes, and cellular homeostasis. Our findings may provide candidate molecular features and pathways for further investigation of stress-associated phenotypes in crayfish.