Molecular characterization of CIRBP from Takifugu fasciatus and its potential roles in cold-induced liver damage.

As a potent stressor, environmental cold stress induces severe mitochondrial dysfunction with the overproduction of reactive oxygen species (ROS) in fish, resulting in liver damage. However, the molecular mechanisms underlying the cold-induced liver damage remain unclear. In the present study, the cold-inducible RNA-binding protein (CIRBP) from Takifugu fasciatus was characterized, and its role in cold-induced oxidative stress damage was investigated. An acute liver injury model was constructed by exposing T. fasciatus individuals to temperatures of 25, 19, and 13 °C. Cold exposure markedly induced histomorphological liver injury and triggered endogenous apoptosis and NLRP3 inflammatory response. Cold treatment significantly increased CIRBP gene expression. A similar expression pattern was detected for thioredoxin (TRX), suggesting that these two proteins play a role in the establishment of cold adaptation. CIRBP binds directly to the 3'-UTR of TRX. Furthermore, in vivo experiment showed that, when CIRBP expression in T. fasciatus is knocked down, the time to loss equilibrium significantly shortened at 13 °C. Taken together, our study revealed that CIRBP is a critical protective factor against cold induced liver damage and that the CIRBP/TRX pathway could function as an underlying mechanism for cold adaptation in teleosts.