Identification And Functional Study Of Inhibitors Targeting EBOVVP30 And The Important Proteins Related To Immune Regulation Of SARS-CoV-2

As one of filovirus,Ebola virus can cause highly pathogenic and has a high fatality rate.It can cause severe hemorrhagic fever and threaten human life and health worldwide.VP30 protein is a specific transcriptional regulator of filoviruses.In our previous study of EBOV VP30,it was found that VP30 regulates the synthesis of viral RNA by interacting with nucleocapsid protein NP.This provides us a new direction for the development of anti-Ebola virus drugs:starting from the transcription and replication of the virus,looking for key regulatory factors to block Ebola virus will be an effective ways to inhibit Ebola virus.Based on the above findings and theoretical basis,we selected the VP30/NP binding interface as a new target for anti-Ebola drugs screening,and established a reasonable and effective drug screening method to screen and verify the antiviral agents targeting Ebola virus VP30 including the peptide and small-molecule antiviral inhibitors.Furthermore,this study elucidated the antiviral pharmacological mechanism through a variety of physicochemical and cell biological experiments,and described the inhibitors in disrupting of the VP30/NP binding interface to prevent Ebola virus transcription and replication.At the same time,the innovative use of combination drugs has obtained a drug combination with outstanding anti-Ebola virus activity.These results provided a comprehensive approach to efficiently identify inhibitors acting at the VP30/NP interface.Meanwhile,the small-molecule inhibitors and combinations reported in this study may provide new strategies for anti-Ebola drug development.COVID-19 is a severe acute respiratory syndrome caused by the novel coronavirus SARS-CoV-2.The continuous mutation of SARS-CoV-2 virus poses a challenge to the existing antibody drug treatment strategies,especially the structure and function of important immunomodulatory proteins,which play a key role in the evolution of the virus and immune escape response.In the study of the interferon signaling pathway between the virus and the host,it was found that in addition to initiating the transcription and replication of the viral genome,the SARS-CoV-2 PLpro protein can also bind to the interferon-stimulating factor ISG15,and has de-ISG activity,inhibiting Inflammatory response and antiviral signal transduction,antagonize the host’s interferon signaling pathway,inhibit the host’s innate immune response,and play an important role in the process of viruses evading innate immunity.The accessory protein ORF8 of SARS-CoV-2 can mediate interactions with MHC-I that render the virus undetectable in infected cells,thereby evading the host immune system and suppressing the host immune response.At the same time,the rapid evolution of the ORF8 protein in the virus also directly affects its interference with the immune system,resulting in immune escape of the virus,reducing or destroying the defense strategy of the interferon system,resulting in the escaping of virus to host recognition.This study starts with the important immunomodulatory proteins of the novel coronavirus,including the discovery of novel inhibitors of PLpro protein and the structural and functional studies of ORF8 protein:Based on the PLpro/ISG15 binding interface,competitive ISG15 protein inhibitors and PLpro protein specific antibodies were obtained,which could act on the PLpro/ISG15 binding interface and play the anti-SARS-CoV-2 virus effect by destroying the interaction between PLpro and human ISG15.ORF8 with unique structural characteristics was recovered,and the relationship between its structural details and the immune escape mechanism of the virus was analyzed guidably.This research provides a novel strategy to exert antiviral effects by interfering with viral immunomodulatory mechanisms.Taking the key binding interface of viral protein as the target of drug action is a hot and difficult issue in the international research and development of new drugs.In this paper,the virus protein interaction interface is the target of the research work.The antiviral research on the interaction interface between the important human pathogenic virus Ebola virus VP30/NP and the SARS-CoV-2 virus PLpro/ISG15 interface can provide new ideas for the screening of new antiviral inhibitors.