PcVDAC promotes WSSV infection by regulating the apoptotic activity of haemocytes in Procambarus clarkii

Apoptosis is programmed cell death that is strictly regulated by a series of related genes and is of great importance in resisting pathogen invasion and maintaining cell environment homeostasis. Among apoptotic proteins, the voltage-dependent anion channel protein (VDAC) plays a key role in the mitochondrial apoptosis pathway because of its close connection with changes in mitochondrial membrane potential. However, the role of VDAC in apoptosis and immune regulation in Procambarus clarkii is poorly understood. In this study, the VDAC gene in P. clarkii (PcVDAC) was cloned by rapid amplification of cDNA ends (RACE) technology. The gene was found to have a total length of 2277 bp, including a 194-bp 5'-UTR, 1234-bp 3'-UTR and 849-bp open reading frame (ORF), and to encode 282 amino acids. PcVDAC was expressed in all tissues tested, and its expression was upregulated after white spot syndrome virus (WSSV) infection (P < 0.05). The RNA interference (RNAi) method was used to explore the role of PcVDAC in WSSV infection. The results showed that the number of WSSV copies in haemocytes was significantly reduced after RNAi (P < 0.05), and the survival rate was significantly increased. In addition, after RNAi, the apoptosis rate was significantly increased (P < 0.05), the mitochondrial membrane potential was reduced (P < 0.01), and the expression of caspase-3 and other genes was upregulated (P < 0.05). These results indicate that PcVDAC promotes the replication of WSSV in P. clarkii by inhibiting haemocytes apoptosis. Therefore, the results presented in this paper provide new insights into the immune response of P. clarkii infected with WSSV.