Fish Shellfish Immunol 2026 May 16;:111427. doi: 10.1016/j.fsi.2026.111427.

Dynamic exosomal proteomic response of the sea cucumber Apostichopus japonicus to Vibrio splendidus challenge.

???displayArticle.abstract???
In vertebrates, exosomes are crucial for intercellular communication and participate in various immune responses. However, their functions in invertebrates remain largely unknown. Following Vibrio splendidus infection, exosome secretion is upregulated in the sea cucumber (Apostichopus japonicus). In this study, Astral Data-Independent Acquisition (DIA) mass spectrometry was employed to characterize the exosomal proteomic response of A. japonicus to lipopolysaccharide (LPS) derived from V. splendidus at 0, 12, and 48 hours following stimulation. A total of 868, 977, and 958 proteins were identified from the coelomic fluid exosomes at these respective time points. Venn analysis revealed 65 core proteins that were consistently upregulated at both 12 and 48 h. Among these, 15 candidate proteins related to immunity were identified, including potential exosomal markers CD63 and CD151, along with the key immune modulator TIMP1. Gene Ontology (GO) and KEGG pathway analyses indicated a temporal shift in the immune response. The early response at 12 h was characterized by the activation of pathways related to stress, such as chaperone-mediated protein folding and oxidoreductase activity. By 48 h, the response progressed toward more specialized immune functions, including immune signal transduction and processes regulating immune protein degradation. This temporal pattern was further validated by quantitative gene expression analysis. A protein-protein interaction (PPI) network analysis predicted a direct interaction between CD63 and TIMP1, while confocal laser scanning microscopy confirmed the co-localization of CD63 with the exosomal membrane. These findings demonstrate that exosomes mediate a dynamic antibacterial immune response in A. japonicus, providing novel insights into the innate immune mechanisms of marine invertebrates.

???displayArticle.pubmedLink??? 42144170
???displayArticle.link??? Fish Shellfish Immunol