Mechanism Of PRV Inhibiting LXR Expression And Promoting Virus Replicatin

Pseudorabies(PR)caused by Pseudorabies Virus(PRV)has caused great economic losses to pig industry in China.Liver X Receptors(LXRs)are cytokines that regulate cholesterol metabolism.The relationship between Liver X Receptors and PRV has not been reported.In this study,we investigated the molecular mechanism of PRV inhibiting LXR expression and promoting virus replication,providing a new strategy for PREVENTION and control of PRV.The main results are as follows:1.PRV infection down-regulates LXRs expressionIn this study,the expression level of LXRs after PRV infection was detected by QRT-PCR and Western Blot,and the results showed that PRV infection down-regulated the transcription and translation of LXRs in cells.Mice were further infected with PRV nasal drops,and the expression level of LXRs in lung tissues was detected by QRT-PCR and Western Blot three days later.The results showed that THE expression of LXRs in lung tissues was down-regulated after PRV infection.2.LXRs negatively regulates PRV replicationWe then identified the relationship between LXRs and PRV replication.Titer and flow cytometry results showed that LXRs reverse agonist SR9243 and knock Down LXRs expression both promoted PRV replication.The effect of LXRs agonist on PRV replication was further examined.The non-toxic and effective concentrations of four LXRs agonists(LXR-623,T0901317,22R-HC,GW3965)were determined by CCK-8 method.Flow cytometry and titer results showed that the four LXRs agonists significantly inhibited PRV replication.Western Blot results showed that LXRs activation significantly reduced PRV protein expression level.These results suggest that activation of LXRs inhibits PRV replication.3.Activation of LXRs reduces cellular cholesterol levels,thereby inhibiting PRV entry into clathrin-dependent clathrin-coated vesicle dynamicsTo determine how LXRs inhibits PRV replication,the effects of LXRs agonist T0901317 on the life cycle of PRV were examined.The results showed that T0901317 inhibited PRV entry into cells.Filipin staining and biochemical assay results showed that T0901317 inhibited cholesterol increase caused by PRV infection.Qrt-pcr and Western Blot results showed that exogenous cholesterol supplementation could restore PRV into cells.Further experiments on FRAP and cell membrane protein biotinylation confirmed that T0901317 inhibited PRV entry into cells by inhibiting grid vesicle dynamics,and exogenous cholesterol supplementation could restore grid vesicle dynamics and PRV entry into cells.4.T0901317 prevented PRV infection in miceThe survival rate of mice injected with T0901317 was significantly higher than that of control mice.Western Blot and immunohistochemical results showed that the expression of PRV g E in lung tissues of T0901317 mice was lower than that of control mice.H&E staining showed that T0901317 could alleviate lung damage caused by PRV infection.These results suggest that T0901317 can prevent PRV infection in mice.