Single-cell transcriptomic atlas of shrimp hepatopancreas reveals an endoplasmic reticulum stress-dependent immune response to Vibrio parahaemolyticus infection.

Innate immunity represents the sole immune defense system of crustaceans. Single-cell RNA sequencing (scRNA-Seq) has greatly advanced the exploration of invertebrate immune mechanisms, enabling a more detailed understanding of immune responses and their underlying molecular pathways. In this study, we employed single-cell nuclear sequencing (snRNA-Seq) to characterize the cellular atlas of the hepatopancreas in the whiteleg shrimp Litopenaeus vannamei in response to Vibrio parahaemolyticus infection. We captured over 20,000 high-quality cells and classified them into five distinct cell types (B, F, E, M, and R cells). Approximately 1400 to 2800 differentially expressed genes (DEGs) were identified in each of the five cell types. Although R cells exhibited the highest number of DEGs in response to bacterial infection, a substantial proportion of DEGs (approximately 33%) were shared across all five cell types. Further analysis revealed that these common DEGs were primarily enriched in endoplasmic reticulum (ER) stress and cell death-related processes. Concurrently, pseudotime trajectory analysis identified a cluster of DEGs highly associated with the antibacterial response, which showed a close relationship with integrin molecules. Finally, protein-level assessment (Western blot and immunohistochemistry) confirmed the presence and activation of ER stress, protein ubiquitination, apoptosis, and autophagy in hepatopancreatic cells during bacterial infection. In summary, this study enhances our understanding of antibacterial immunity in crustaceans and suggests potential evolutionary parallels of ER stress-induced immunomodulation, a finding that is consistent with stress-associated immune regulatory patterns reported in diverse taxa.