Pc-prx 6 plays an important role in the regulation of antibacterial innate immune in the hepatopancreas of Procambarus clarkii due to its potential antioxidant capacity

Abstract

Mammalian peroxiredoxin (Prx) maintains redox equilibrium and protects cells from oxidative stress by eliminating the accumulation of intracellular reactive oxygen species (ROS). Studies have revealed that members of the Prx family play important roles in multiple processes, including oxidative defense, redox signaling, protein folding, cell cycle progression, DNA integrity, inflammation, and carcinogenesis. However, research on Prx molecules in invertebrates has been insufficient to draw definite conclusions. In particular, studies on their role in the regulation of innate immunity are scarce. In this study, the prx 6 gene was used as the target to carry out a series of biochemical and molecular biological studies in P. clarkii. These studies focused on recombinant expression, the identification of antioxidant effects in vitro, the study of temporal and spatial expression profiles, RNAi in vivo, and the detection of critical innate immune responses. The results indicated that rPc-Prx 6 significantly enhanced the protective effect of the MCO reaction system on plasmid DNA and had clear antioxidant effects. It could strongly combine with S. aureus and E. catarrhalis. Compared with those in the 1 × PBS injection group, the relative expression levels of Pc-prx 6 were clearly increased in certain major immunity-related tissues after challenge with V. harveyi. In addition, the direct knockdown of Pc-prx 6 directly resulted in the upregulation of H₂O₂ content in the crayfish hepatopancreas. Consequently, the hepatopancreatic histomorphology was altered, and the MDA content increased. Moreover, the increase in the expression of NF-κB and some immune effector genes was clearly inhibited. Ultimately, the crayfish survival rate was significantly reduced. Taken together, these findings suggest that Prx 6 plays an important role in antibacterial innate immunity by regulating the H₂O₂ content in invertebrates.