Mechanism Of Host Factors HDAC3 And TBL1XR1 Promoting VSV Replication

Vesicular stomatitis(VS)is caused by Vesicular stomatitis virus(VSV),which is a kind of rapid,highly contagious infectious disease.VSV is a main member of Rhabdoviridae family,which could infect cattle,horse and pig,rodent animals can also be infected.Lesions in mouth and lip could form vesicles after VSV infection.Although VSV can rarely cause death of infected livestock,the secondary infection would cause heavy loss to the animal husbandry economy.Searching for key host factors during the process of VSV infection is an important way for exploring the mechanisms of VSV infection.Histone deacetylases(HDACs)are a class of epigenetic modifying enzymes,which are mainly involved in the structural modification of chromosomes and the regulation of gene expression.The main function of HDAC3 is to catalyze the deacetylation process of histone,maintain the epigenetic modification spectrum of cells,modify non histone and regulate the inflammatory signal pathway in cells.In this study,we found that blocking HDAC3 with RGFP966,a small molecular inhibitor,could inhibit the replication and proliferation of VSV,and gene silencing of Hdac3 by siRNA interference could also restrict the replication and proliferation of VSV.Moreover,over expression of Hdac3 in cells can promote the replication of the virus.These results suggest that HDAC3 plays an important role in VSV transcription and proliferation.We also found that in the case of VSV infection,Hdac3 gene silencing can regulate the interferon stimulating gene(ISG)and its differential regulation.Ifnb1,Ifih1 and Irf3 were down regulated after Hdac3 was silenced,while Mx1,Ifi44,Ifi35 and Irf7 were up regulated.It is suggested that HDAC3 may play an important role in the replication of VSV.Therefore,we established Mx1 silenced cell line by microRNA interference and found that Mx1 gene silencing can significantly up regulate the transcription and replication level of VSV.These results indicate that inhibition or silencing of Hdac3 may prevent VSV from replicating and proliferating by regulating Mx1 level.TBL1XR1 is an important transcription regulator,which regulates the precise occurrence of gene transcription.TBL1XR1 is also an evolutionarily conserved protein with high homology among species.It can be used as an integration subunit to regulate gene transcription by binding with NCoR(nuclear receptor co repressor),SMRT(silencing medium of retinoic acid and thyroid hormone receptor)and HDAC3.Tbl1xr1 and its complexes are involved in the recruitment of unconjugated nuclear receptors(NR)or other regulatory transcription factors(TF)into the promoter region of the regulated gene,which mediates the transcriptional inhibition of the gene.The silenced cell line of Tbl1xr1 was designed and established by the same method above.After VSV infected the cell line,it was found that the silencing of Tbl1xr1 gene could significantly inhibit the transcription and replication of VSV,indicating that HDAC3 and TBL1XR1 might play a synergistic role in the process of assisting VSV infection.In conclusion,we have blocked or silenced host factor HDAC3 by small molecular inhibitors and RNA interference,and found that the replication and proliferation of VSV were significantly down regulated,which reflected that HDAC3 played an important role in the pathogenesis of VSV.This antiviral effect is closely related to the regulation of interferon related genes by HDAC3,and the controlled up regulation of MX1 is one of the reasons why VSV is inhibited.Moreover,we found that silencing TBL1XR1 which interacting with HDAC3 in the nucleus can also restrict VSV replication,indicating that HDAC3 may play a role in promoting VSV through its co inhibition complex in the nucleus.The findings of this study not only lay a theoretical foundation for revealing the pathogenic mechanism of VSV at the apparent level,but also play a guiding role in the prevention and control of VS.