Multi-omics Studies Of MDBK Cells Infected With Different Biotypes Of Bovine Viral Diarrhea Virus

Bovine viral diarrhea virus(BVDV),an important pathogen associated with gastrointestinal,respiratory and reproductive tract diseases of cattle,can cause bovine viral diarrhea-mucosal disease(BVDV-MD),thereby leading to serious economic losses to the global cattle industry.BVDV can be divided into cytopathic type(CP)and non-cytopathic type(NCP).The immune responses of host infected with BVDV fundamentally different among different among different biological types.In early embryonic development,only NCP can establish infection and then develop into persistent infection.In addition,CP infection causes significant damage to the host,while NCP type does not.NCP infection can lead to decreased immunity of cattle and secondary infection with other pathogenic microorganisms.The main reason is that the innate immune response of host will not be induced by NCP infection.However,the study on the immune responses of different biological types of BVDV infected host is very limited.Therefore,in this study,CP and NCP were taken as the research object,and transcriptomics and proteomics sequencing technology were used to analyze the key molecules and signaling pathways of MDBK cells infected different biological BVDV,and the main results were as follows:(1)By detecting the expression of BVDV specific protein E2,it was determined that both CP and NCP successfully infected MDBK cells.The two types of BVDV were inoculated into MDBK cells to observe the degree of cytopathic changes.The obvious cytopathic changes in cells infected with NCP,Subsequently,the TUNEL staining method was used to observe the apoptosis induced by BVDV infection.Then.The results exhibited that the obvious apoptosis can be observed in both CP and NCP,and CP infection caused significantly higher apoptosis rate than that in MDBK infected with NCP.These results indicated that the host cell immune responses triggerd by CP and NCP infections were considerabiy different.(2)Next,we determined the MOI value and infection time of MDBK cells infected with CP and NCP,collected infected samples,and conducted transcriptomic analysis.The results showed that a total of 161 differentially expressed genes(48 up-regulated and 113 downregulated)were identified between the control and CP group.A total of 339 differentially expressed genes(186 up-regulated and 153 down-regulated)were identified in the control vs the NCP group.A total of 319 differentially expressed genes(158 up-regulated and 161down-regulated)were identified in CP vs NCP group.(3)Meanwhile,proteomic analysis was conducted and the results revealed that a total of 1106 differentially expressed proteins(691 up-regulated and 415 down-regulated)were identified between the control group and CP group,and 666 differentially expressed proteins(440 up-regulated and 226 down-regulated)were identified compared control group with NCP type.A total of 6 differentially expressed genes(3 up-regulated and 3 down-regulated)were identified in CP group vs NCP group.(4)Additionally,the results of transcriptomic and proteomic were analyzed jointly,and the results indicated that almost expression changes of gene were consistent with and protein levels.GO annotation and KEGG pathway analysis were performed,and the results manifested that the up-regulated proteins were mainly involved in phagocytosis and glycogen biosynthesis,and the down-regulated proteins are mainly involved in ubiquitinmediated protein degradation pathway and cholesterol metabolism signaling pathway.In addition,the differentially expressed genes in multiple omics results were verified by q RTPCR,and the expression trend of genes identified in omics was consistent with the results of q RT-PCR,which further demonstrated the reliability of the omics results.In conclusion,our project conducted the conjoints analysis of transcriptomic and proteomics of MDBK cells infected with different biological strains of BVDV,and screened differentially expressed genes and proteins.These genes and proteins were involved in innate immunity,antiviral regulation and apoptosis regulation in toll-like receptor signaling pathway,TNF signaling pathway,MAPK signaling pathway,endoplasmic reticulum protein processing and apoptosis signaling pathway,suggesting that the host immune responses triggered by different biotypes BVDV indeed showed distinctly different.Our study provides a research direction for the mechanism of interaction between different biotypes and also provides a theoretical basis for developing drug targets against different biotypes BVDV.