The Preliminary Study On The Pathogenesis Mechanism Of HEV Persistent Infection

Hepatitis E virus(HEV)is a main viral hepatitis pathogen that threated public health.HEV infection was recognized as an acute self-limited disease,patients can recover themselves after 3 ～ 4 weeks.However,the majority of HEV infections in immunocompromised individuals,such as solid-organ transplant recepients and patients with HIV infection,are likely to progress to persistent infection.But,the pathogenesis of HEV persistent infection remains unclear.The aim of this paper is to explore the molecular mechanism of HEV persistent infection from both host immune system and viral mutation in vitro and in vivo.(1)Establishment an immunosuppressived BALB/c mice HEV persistent infection animal model to explore the relationship between suppressed host immune system and HEV persistent infection.(2)Construction three HEV mutant strains and identification their infectivity in vitro.(3)Establishment HEV mutation caused persistent infection in BALB/c mice animal models to explore the relationship between viral mutations and HEV persistent infection.(4)The molecular mechanism of HEV persistent infection.(5)Screening anti-HEV drugs based on HEV infected animal model(1)Establishment an immunosuppressived BALB/c mice HEV persistent infection animal model to explore the relationship between suppressed host immune system and HEV persistent infectionThe immune system of BALB/c mice were pre-suppressed by using immunosuppressants(rapamycin and tacrolimus),and then infected with HEV.Persistent HEV infection was successfully established 12 weeks after infection with genotype 4 HEV.HEV RNA was detected in the feces,serum and tissues samples of HEV-infected BALB/c mice from 7 day to 30-week post-inoculation,which provide an important animal model for exploring the mechanism of HEV persistent infection.(2)Construction three HEV mutant strains and identification their infectivity in vitroThree recombinant HEV infectious clones(including G1-HEV strain,G2-HEV strain and G3-HEV strain)were constructed through reverse genetics technology.The A549 lung cancer cells were transfected with recombinant HEV strain to identify the infectivity.These recombinant infectious clones were able to replicate efficiently in A549 cells.(3)Establishment HEV mutation caused persistent infection in BALB/c mice animal models to explore the relationship between viral mutations and HEV persistent infectionBALB/c mice were inoculated with three recombinant HEV infectious clones seperately.Mice inoculated with G1-HEV strain caused HEV persistent infection and lead to pathological injury in liver.However,mice inoculated with G2-HEV strain or G3-HEV strain cause acute HEV infection.(4)The molecular mechanism of HEV persistent infectionAcute strain,persistent infection strain,and three recombinant HEV infectious clones were inoculated Huh7.5.1 cells to detect the expression of interferon-stimulated genes,to analyze the molecular mechanism of HEV persistent infection.(5)Screening anti-HEV drugs based on HEV infected animal modelUp to now,there is no specific drug for HEV treatment in clinical.In this paper,HEV persistent infection in BALB/c mice model was used to screen the drugs for HEV infection.However,no matter ribavirin,interferon α or sofosbuvir,single or combination treatment,there is no effect on HEV clearance.In contrast,severy liver damange cause by ribavirin treatment.Results indicate that host immunosuppression and viral mutations are the main causes of HEV persistent infection.The successful establishment of HEV persistent infection in BALB/c mice models provide a very immportant foundation for further research on the pathogenesis of HEV infection.