Background  Grass carp reovirus (GCRV) infection can cause leakage bleeding by increasing vascular endothelial permeability.

Objective To investigate the functional mechanism of adenylate cyclase 3 (AC3) mediated GCRV infection, a series of studies were conducted in Ctenopharyngodon idella kidney (CIK) cells.

Methods AC3 overexpression was successfully achieved in CIK cells. Real-time fluorescent quantitative polymerase chain reaction (qPCR) was used to detect the relative expression of ac3, claudin c, claudin 15, claudin 18, irf3, irf7, ifn1 and ifn2 at different time points (0 h, 12 h, and 24 h) of GCRV infection. The protein level of GCRV VP7 was detected by Western blot (WB). The transendothelial electrical resistance (TEER) of the CIK cell layer under various conditions was measured using a cell resistance meter, while the connections between CIK cells were examined using a transmission electron microscope.

Results The results showed that AC3 overexpression significantly enhanced the expression of tight junction molecules claudin 15 and claudin 18 in CIK cells, but had no significant effect on the expression levels of interfering semaphorin pathway genes irf3, irf7, ifn1 and ifn2. However, the protein amount of GCRV VP7 was inhibited. The transepithelial electrical resistance assay demonstrated that AC3 overexpression significantly increased the resistance of the CIK cell layer. Transmission electron microscopy results indicated that AC3 overexpression reduced the extent of damage to CIK cell-to-cell junctions caused by GCRV infection.

Conclusion In summary, AC3 can influence the relative expression of claudin molecules and the barrier function of cells, inhibiting GCRV proliferation within these cells.

Significance This study introduces a novel approach for discovering GCRV resistance-related molecules from the perspective of cell permeability.