Impact of HEV infection on the human hepatic innate immune response in human liver chimeric mice Ibrahim M. Sayed1,2, Lieven Verhoye1, Lander Foquet1, Florence Abbravanel3, Ali Farhoudi1, Geert Leroux-Roels 1, Jacques Izopet3, Philip Meuleman1 1Laboratory of Liver Infectious Diseases, Department of Clinical Chemistry, Microbiology and Immunology, UGENT, Ghent, Belgium. 2Microbiology and Immunology Department, Assiut University, Assiut, Egypt. 3INSERM U1043, IFR-BMT, CHU Purpan, Toulouse, France; Université Paul-Sabatier, Toulouse, France; Laboratory of Virology, CHU Purpan, Toulouse, France. Background Transcriptome analysis Every year approximately 20 million people become infected with HEV HEV causes acute, chronic and extra-hepatic manifestation Transmission routes: fecal-oral, foodborne, vertical, blood transfusion Lack of robust cell culture systems covering all HEV genotypes Non human primates are susceptible to HEV gt1-4, Pigs are susceptible to HEV gt3-4 Human liver chimeric uPA/SCID mice are susceptible to HEV infection Aim: Study the impact of HEV infection on hepatic innate immune response of human liver chimeric mice Experimental protocol Mice Humanized uPA+/+-SCID mice infected with HEV Non infected humanized uPA+/+-SCID mice HEV inocula: Stool suspension of infected chimpanzee (genotype 1, Sar-55 strain) Stool from infected patient (genotype 3f) Analysis Detect and quantify HEV RNA in mouse plasma and stool Liver analysis: quantification HEV RNA inside mouse liver Gene expression HEV gt1 and HEV gt3 infected liver Liver fragments from freshly sacrificed mice RT-qPCR & human-specific primer/probe combinations Non-inoculated humanized mice as negative control Five house keeping genes (stability using GeNom) Up-/down-regulated gene: fold change ≥2 Infection of humanized mice with HEV HEV gt1 is more virulent than HEV gt3 Transcriptome analysis Conclusion Human liver chimeric mice can be used to study HEV pathogenesis Numerous genes are upregulated upon HEV gt1 infection Up-regulation was more pronounced at later time points during infection Only minimal upregulation upon HEV gt3 infection Further research is needed to define the factors responsible for different profile between gt1 and gt3 Red: Up regulated gene : Green: non affected gene Dotted vs Solid: 4 week , 9 week of HEV gt1 infection respectively