Hemocyanin negatively regulates phenoloxidase activation via phenylalanine-tyrosine metabolism to enhance immune defense in AHPND-infected Penaeus vannamei

ABSTRACT: Hemocyanins function not only as oxygen carriers in the hemolymph of arthropods and molluscs but also as an important multifunctional immune molecule. In this study, we observed a significant increase in hemocyanin expression and a decrease in PO activity in Penaeus vannamei infected with acute hepatopancreatic necrosis disease (AHPND). Using gas chromatography-mass spectrometry (GC-MS)-based metabolomics, we found that knockdown of the hemocyanin gene (PvHMC) led to significant reductions in phenylalanine and tyrosine levels. Subsequent qPCR, PO activity assays, and LC-MS analyses revealed that PvHMC knockdown significantly elevated the transcript levels of key enzymes in the phenylalanine-tyrosine metabolic pathway, accompanied by increased L-Dopa levels and enhanced PO activity. In contrast, exogenous supplementation of phenylalanine or tyrosine downregulated these four enzymes and reduced PO activity. Furthermore, after PvHMC knockdown, inhibiting phenylalanine hydroxylase with 4-Chloro-DL-phenylalanine (PCPA) or tyrosine hydroxylase with 3-Iodo-L-tyrosine (3-IT) increased phenylalanine or tyrosine levels, decreased the expression of the corresponding enzymes, and reduced both L-Dopa content and PO activity. Collectively, these results demonstrate that during Vibrio parahaemolyticus (VpAHPND) infection, PvHMC is significantly downregulated and negatively regulates PO activity via the phenylalanine-tyrosine metabolism, thereby enhancing immune defense. This study elucidates a novel metabolic mechanism through underlying PvHMC-mediated regulation of the PO cascade regulation, providing new insights into the interplay between metabolism and immunity in shrimp.

INSTRUMENT(S): Gas Chromatography MS - alternating - high-polarity

PROVIDER: MTBLS14563 | MetaboLights | 2026-05-22

REPOSITORIES: MetaboLights