Effect Of HCV Structural Proteins On HCV Cell-to-cell Transmission And Anti-HCV Drugs Screening Of Flavonoids

Hepatitis C virus(HCV)infection is a worldwide public health problem.About 2-3% of the world population are infected with HCV.Chronic infection of HCV is among the most frequent causes of liver cirrhosis and hepatocellular carcinoma.Recently,the newly introduced drugs know as direct-acting antivirals(DAAs)against HCV is more effective,but because of its high price and drug tolerance,the research and development of new drugs and vaccines against HCV infection is still attentions.Studies have shown that,virus spreading through cell-to-cell transmission is the major cause of DAA-resistant HCV persistent infection and difficulty to eliminate.When HCV spread to the surrounding adjacent cells by cell-to-cell transmission,it can evade immune surveillance and neutralization from neutralizing antibodies,thus hampers viral eradication.Therefore,it is crucial to further explore the influencing factors and mechanisms of HCV cell-to-cell transmission.Meanwhile,it will also contribute to the development of new antiviral drugs to improve the status of hepatitis C treatment.In this paper,we researched the effect of HCV structural proteins on HCV cell-to-cell transmission,and screened anti-HCV drugs among 107 flavonoids of artificial synthesis.During the research of the effect of HCV structural proteins on HCV cell-to-cell transmission,first,we analyzed the virological characteristics of wild-type virus and structural protein deficient virus.The results showed that wild-type virus Jc1 can normally express the structural proteins and non-structural proteins in cells,and release large amounts of RNA,Core proteins and infective virus particles in the supernatant.Structural protein deficient virus can’t express the partly deleted structural proteins.They can release large amounts of RNA in the supernatant,but can’t secrete abundant Core proteins and infective virus particles.Then we established the HCV cell-to-cell transmission system by using Huh 7.5.1 VISI-GFP cells as donor cells and Huh 7.5.1 VISI-m Cherry cells as recipient cells.And we researched the effect of HCV structural proteins on HCV cell-to-cell transmission utilizing this system.The results indicated that wild-type virus Jc1 can normally spread by cell-to-cell transmission between adjacent cells,while the structural protein deficient virus,Jc1ΔCore,Jc1ΔE1E2,Jc1Δp7 and sg-JFH1,can’t spread by cell-to-cell transmission.It declared that HCV structural proteins were essential for HCV cell-to-cell transmission.We screened anti-HCV drugs among 107 flavonoids of artificial synthesis by using dual-luciferase reporter assay system.The screening results showed that all these flavonoids had no effect on HCV replication,but the NO.45,46,47,52,58,66,69,100,106,107 flavonoids had a certain inhibitory effect on HCV assembly and release.Among them,the NO.45,46,47,52,58 flavonoids had about 50% inhibition on HCV,and the NO.66,69,100,106,107 flavonoids had about 40% inhibition on HCV.Since the inhibitory effect of HCV is not strong,these flavonoids cannot be used as anti-HCV candidate drugs.