Transcriptome analysis the Astakine induced proliferation of hemocytes to regulate anti-bacterial immunity in Scylla...

Vibrio alginolyticus presents a significant threat to the aquaculture sector of crustaceans, specifically Scylla paramamosain. Hemocyte proliferation is critical for the host's ongoing defense against bacterial pathogens and the maintenance of immune homeostasis. However, the molecular pathways governing hemocyte proliferation and immune responses in crustaceans are not fully elucidated. Building on our prior study, this study examines the effects of V. alginolyticus infection on immune tissue integrity and intestinal microbiota composition in S. paramamosain, with a focus on the role of the hemocyte proliferation regulator Astakine in host immune defense. Our results indicate that V. alginolyticus infection induces substantial histopathological injury to the hepatopancreas, gills, and intestinal tissues. Additionally, V. alginolyticus infection significantly modulates the composition and diversity of the intestinal microbiota. Astakine inhibits V. alginolyticus replication both in vivo and in vitro, while enhancing hemocyte proliferation, which promotes cell proliferation by accelerating G1/S cell cycle progression, and stimulating the secretion of antimicrobial peptides such as crustin and ALFs. Transcriptomic profiling reveals that Astakine activates cell proliferation signaling pathways, suppresses apoptosis pathways, and up-regulates immune-related genes including jak, stat, ALF, Hsp90, and PI3K, while down-regulating apoptosis-associated gene caspase-2. This study offers new insights into the molecular mechanisms by which crustacean hemocyte proliferation contributes to antibacterial immunity.