Transcriptomic analysis revealed the potential regulatory mechanism of extracellular vesicles on the innate immunity in Chlamys farreri.
Extracellular vesicles (EVs), as antimicrobial factors, load a variety of immune-related molecules, play a complex and critical role in host-pathogen interactions. The regulatory mechanism of how EVs respond to external stimuli by regulating immune regulatory elements in the innate immune response of marine invertebrates remains unresolved. To address this, we conducted a global transcriptomic analysis of hemocytes in Chlamys farreri stimulated by EVs derived from different sources. Transcriptomic analysis identified 892 specifically upregulated and 246 specifically downregulated genes in the group of scallops injected with EVs obtained after LPS stimulation (group S) relative to the group of scallops injected with PBS buffer (group P). Functional annotation analysis revealed that the differentially expressed genes (DEGs) participate in critical immune signaling pathways, including the NOD-like receptor, RIG-I-like receptor, and HIF-1 signaling pathways. Among the DEGs unique to the group S, we identified canonical genes linked to autophagy, apoptosis, and immune responses, such as cell division control protein 42 homolog (CDC42), dual specificity protein phosphatase 1 (DUSP1), TNF receptor-associated factor 3 (TRAF3), Caspase 3 (CASP3), serine/threonine-protein kinase ULK3 (ULK3), and Myeloid differentiation primary response protein MyD88-3 (MyD88-3). Protein-protein interaction (PPI) network analysis pointed to ADP-ribosylation factor (CDKN2A), phosphatidylinositol 3,4,5-trisphosphate 3-phosphatase and dual-specificity protein phosphatase (PTEN), CDC42, CASP3, and the downregulated protein heat shock protein 90 (HSP90) as prominent hub DEGs involved in the regulation of innate immunity. Temporal analysis of selected immune DEGs further demonstrated the immunomodulatory role of EVs in Chlamys farreri. Our study establishes that EVs are essential for regulating innate immunity in marine invertebrates, offering novel insights for shellfish disease prevention and control.