TP22: From genotype to phenotype: Towards a better understanding of hepatitis E virus tropism and chronic infection

The nature of hepatitis E virus (HEV) infections varies depending on the genotype. We found that the HEV capsid is critical for evading the innate immune response, thus promoting persistent infections in hepatocytes. As our studies have so far focused on a zoonotic HEV-3 strain, we now want to perform a comparative analysis of HEV-3 with HEV-1 biology. To achieve this, we plan to establish a molecular HEV-1 clone that will serve as the basis for comparing the innate immune response induced by HEV-3 infections using two approaches: First, human pluripotent stem cell-derived co-culture systems that integrate innate immune cells; second, comparing HEV-induced responses in both human and porcine stem cell-derived hepatocytes. We expect to gain a deeper understanding of HEV tropism and chronic infection.

Dr. Viet Loan Dao Thi

Fu RM, Decker CC, Dao Thi VL. (2019) Cell Culture Models for Hepatitis E Virus. Viruses. 3;11(7):608. doi: 10.3390/v11070608.

Chi H, Qu B, Prawira A, Maurer L, Hu JG, Fu RM, Lempp FA, Zhang Z, Grimm D, Wu X, Urban S, Dao Thi VL. (2023) Human pluripotent stem cell-derived hepatocyte-like cells for hepatitis D virus studies. bioRxiv. doi: 10.1101/2023.10.13.561984.

Wu X, Dao Thi VL, Liu P, Takacs CN, Xiang K, Andrus L, Gouttenoire J, Moradpour D, Rice CM. (2017) Pan-Genotype Hepatitis E Virus Replication in Stem Cell-derived Hepatocellular Systems. Gastroenterology. doi: 10.1053/j.gastro.2017.10.041.

Dao Thi VL, Wu X, Belote RL, Andreo U, Takacs CN, Fernandez JP, Vale-Silva LA, Prallet S, Decker CC, Fu RM, Qu B, Uryu K, Molina H, Saeed M, Steinmann E, Urban S, Singaraja RR, Schneider WM, Simon SM, Rice CM. (2020) Stem cell-derived polarized hepatocytes. Nat Commun. 11, 1677. doi: 10.1038/s41467-020-15337-2.

Wu XF, Thi VLD, Huang YM, Billerbeck E, Saha D, Hoffmann HH, Wang YM, Silva LAV, Sarbanes S, Sun T, Andrus L, Yu Y, Quirk C, Li M, MacDonald MR, Schneider WM, An XL, Rosenberg BR, Rice CM. (2018) Intrinsic Immunity Shapes Viral Resistance of Stem Cells. Cell. 172, 423-+. doi: 10.1016/j.cell.2017.11.018.

Dao Thi VL, Debing Y, Wu X, Rice CM, Neyts J, Moradpour D, Gouttenoire J. (2016) Sofosbuvir Inhibits Hepatitis E Virus Replication In Vitro and Results in an Additive Effect When Combined With Ribavirin. Gastroenterology. 150, 82-85 e84. doi: 10.1053/j.gastro.2015.09.011.

Maurer L, El Andari J, Rapti K, Spreyer L, Steinmann E, Grimm D, Dao Thi VL. (2022) Induction of Hepatitis E Virus Anti-ORF3 Antibodies from Systemic Administration of a Muscle-Specific Adeno-Associated Virus (AAV) Vector. Viruses. 14. doi: 10.3390/v14020266.

Csernalabics B, Marinescu MS, Maurer L, Kelsch L, Werner J, Baumann K, Zoldan K, Reuken P, Bruns T, Bengsch B, Neumann-Haefelin C, Hofmann M, Thimme R, Panning M, Dao Thi VL, Boettler T. (2023) Efficient formation and maintenance of humoral and CD4 T cell immunity targeting naked but not quasi-enveloped virions in acute-resolving hepatitis E infection. BioRxiv. doi: 2023/563038. 10.1101/2023.10.19.563038

Fu RM, Engels Z, Weihs JA, Murle J, Klohn M, Todt D, Hu JG, Steinmann E, Boettler T, Lozach PY, Lemon SM, Dao Thi VL. (2023) A high-content RNA-based imaging approach reveals integrin beta 1 as a cofactor for cell entry of non-enveloped hepatitis E virus. BioRxiv. doi: 2023.10.27.564362

Project in detail +

Hepatitis E virus (HEV) is a leading cause of acute viral hepatitis worldwide. Depending on the genotype (GT), HEV infection can be self-limiting and is restricted to humans (e.g. HEV-1/2) or can infect a wide range of hosts, including pigs, from which it can be transmitted zoonotically to humans (e.g. HEV-3/4) and persist in immunocompromised individuals.
We discovered that the HEV capsid protein ORF2 plays a critical role in establishing HEV-3 replication in the presence of a sustained type III interferon (IFN)-mediated innate immune response in hepatocytes: On the one hand, we found that the capsid likely induces the HEV genome replication site via liquid-liquid phase separation through the N-terminal intrinsically disordered region (with Bartenschlager and Schütz/Seitz). On the other hand, and in close collaboration with Binder, we learned that ORF2 can also downregulate the critical innate immune adaptor molecule NEMO and directly interfere with the induction of antiviral and pro-inflammatory responses. As our studies have so far focused on a zoonotic HEV-3 strain and owing to our previous observation that HEV-1 replication induces a stronger and potentially infection-limiting antiviral response in hepatocytes than HEV-3, we will conduct a comparative and mechanistic analysis of HEV-3 with HEV-1 biology.

For this, we need a reproducible, replicative HEV-1 strain, which we will establish by a synthetic DNA approach and cell culture adaptation in our aim 1. In our aim 2, we challenge the role of the innate immune response in the outcome of HEV infection, i.e. acute self-limiting or persistent. Since the type III IFN response is considered to be weaker than the type I IFN response, we will compare the outcome of HEV-1 and -3 infections in the presence of both type I and III IFN, by establishing hepatocyte and macrophage/pDC co-cultures (with Bartenschlager, Binder/Beisel, Lohmann, and Z03). In our aim 3, we compare the innate immune response to HEV-1 and -3 infection in human and porcine hepatocytes to investigate whether HEV-3 has a greater ability to antagonize the innate immune response due to the need to counteract the innate immune system of different host species, including its natural host, the pig (with Binder/Beisel, and Lohmann). For all aims, we capitalize on our expertise on model system development using pluripotent stem cells, which we will make available to several groups within the CRC (Bartenschlager, Binder/Beisel, Lohmann, Urban/Nkongolo, Schreiner, and Cerwenka). Overall, our aims will lead to a better understanding of HEV tropism and chronic infection.