TP09: Control of hepatitis virus infection by the interferon system and by exploiting virus – host cell interactions

Hepatitis B, C and D viruses (HBV, HCV, HDV) can establish persistence, but the underlying mechanisms are not fully understood. We have studied the role of the intracellular RNA sensor LGP2 in controlling HDV and HCV infection. In addition, we identified host cell proteins associated with HBV virions and subviral particles (SVPs) and of relevance for the viral replication cycle. In the next funding period, we address two major objectives. First, the regulation of LGP2 regarding the induction of the interferon response. Second, the mechanism how HBV virion and SVP associated cell proteins promote viral replication and the lipidome of these particle types with the aim to identify potential drug targets.

Prof. Dr. Dr. hc. Ralf Bartenschlager

Mutz P, Metz P, Lempp FA, Bender S, Qu B, Schoneweis K, Seitz S, Tu T, Restuccia A, Frankish J, Dachert C, Schusser B, Koschny R, Polychronidis G, Schemmer P, Hoffmann K, Baumert TF, Binder M, Urban S, Bartenschlager R. (2018) HBV Bypasses the Innate Immune Response and Does Not Protect HCV From Antiviral Activity of Interferon. Gastroenterology. 154, 1791-1804 e1722. doi:10.1053/j.gastro.2018.01.044.

Zhang Z, Filzmayer C, Ni Y, Sultmann H, Mutz P, Hiet MS, Vondran FWR, Bartenschlager R, Urban S. (2018) Hepatitis D virus replication is sensed by MDA5 and induces IFN-beta/lambda responses in hepatocytes. J Hepatol. 69, 25-35. doi:10.1016/j.jhep.2018.02.021.

Zhang Z, Ni Y, Lempp FA, Walter L, Mutz P, Bartenschlager R, Urban S. (2022) Hepatitis D virus-induced interferon response and administered interferons control cell division-mediated virus spread. J Hepatol. 77, 957-966. doi:10.1016/j.jhep.2022.05.023.

Gillich N, Zhang Z, Binder M, Urban S, Bartenschlager R. (2023) Effect of variants in LGP2 on MDA5-mediated activation of interferon response and suppression of hepatitis D virus replication. J Hepatol. 78, 78-89. doi:10.1016/j.jhep.2022.08.041.

Pham MT, Lee JY, Ritter C, Thielemann R, Meyer J, Haselmann U, Funaya C, Laketa V, Rohr K, Bartenschlager R. (2023) Endosomal egress and intercellular transmission of hepatic ApoE-containing lipoproteins and its exploitation by the hepatitis C virus. PLoS Pathog. 19, e1011052. doi:10.1371/journal.ppat.1011052.

Qu B, Nebioglu F, Leuthold MM, Ni Y, Mutz P, Beneke J, Erfle H, Vondran FWR, Bartenschlager R, Urban S. (2022) Dual role of neddylation in transcription of hepatitis B virus RNAs from cccDNA and production of viral surface antigen. JHEP Rep. 4, 100551. doi:10.1016/j.jhepr.2022.100551.

Cortese M, Lee JY, Cerikan B, Neufeldt CJ, Oorschot VMJ, Kohrer S, Hennies J, Schieber NL, Ronchi P, Mizzon G, Romero-Brey I, Santarella-Mellwig R, Schorb M, Boermel M, Mocaer K, Beckwith MS, Templin RM, Gross V, Pape C, Tischer C, Frankish J, Horvat NK, Laketa V, Stanifer M, Boulant S, Ruggieri A, Chatel-Chaix L, Schwab Y, Bartenschlager R. (2020) Integrative Imaging Reveals SARS-CoV-2-Induced Reshaping of Subcellular Morphologies. Cell Host Microbe. 28, 853-866 e855. doi:10.1016/j.chom.2020.11.003.

Ke Z, Oton J, Qu K, Cortese M, Zila V, McKeane L, Nakane T, Zivanov J, Neufeldt CJ, Cerikan B, Lu JM, Peukes J, Xiong X, Krausslich HG, Scheres SHW, Bartenschlager R, Briggs JAG. (2020) Structures and distributions of SARS-CoV-2 spike proteins on intact virions. Nature. 588, 498-502. doi:10.1038/s41586-020-2665-2.

Neufeldt CJ, Cerikan B, Cortese M, Frankish J, Lee JY, Plociennikowska A, Heigwer F, Prasad V, Joecks S, Burkart SS, Zander DY, Subramanian B, Gimi R, Padmanabhan S, Iyer R, Gendarme M, El Debs B, Halama N, Merle U, Boutros M, Binder M, Bartenschlager R. (2022) SARS-CoV-2 infection induces a pro-inflammatory cytokine response through cGAS-STING and NF-kappaB. Commun Biol. 5, 45. doi:10.1038/s42003-021-02983-5.

Tabata K, Prasad V, Paul D, Lee JY, Pham MT, Twu WI, Neufeldt CJ, Cortese M, Cerikan B, Stahl Y, Joecks S, Tran CS, Luchtenborg C, V'Kovski P, Hormann K, Muller AC, Zitzmann C, Haselmann U, Beneke J, Kaderali L, Erfle H, Thiel V, Lohmann V, Superti-Furga G, Brugger B, Bartenschlager R. (2021) Convergent use of phosphatidic acid for hepatitis C virus and SARS-CoV-2 replication organelle formation. Nat Commun. 12, 7276. doi:10.1038/s41467-021-27511-1.

Project in detail +

In this funding period we will focus on two major aims: First, to finalize our studies on LGP2; second, shifting the focus from HCV and HDV to HBV, we will follow up the HBV proteome and extend this study to the lipidome of HBV virions and SVPs. The ultimate goal is to unravel previously unknown HBV-host cell interactions and to identify possible targets suitable to suppress especially the production and release of SVPs from cells, with the aim of identifying strategies to boost antiviral immunity in chronic hepatitis B patients.
Regarding LGP2 (aim 1), we will continue our studies of cellular interaction partners (with Pichlmair). In collaboration with Binder/Beisel, Lohmann, Urban/Nkongolo and Dao Thi, the identified LGP2 interactants will be validated using functional and biochemical analyses. In addition, we will continue the follow-up studies of the phosphorylation sites in LGP2 (with Pichlmair) and expand these analyses to other cytosolic RNA sensors (with Binder, Lohmann, Urban/Nkongolo, Dao Thi).
Regarding aim 2, we pursue three complementary approaches. First, with Protzer/Wettengel, Urban/Nkongolo, Schütz/Seitz and Pichlmair, we will conduct mechanistic studies on host cell proteins present only in HBV virions, or both in virions and SVPs, or in other secreted particle types (non-enveloped “naked” capsids, genome-free “empty” virions). Second, we will aim to determine the role of lipids in the HBV replication cycle. This includes lipid imaging and studies of lipid biosynthesis pathways. Third, in a very close collaboration with Schütz/Seitz we aim to characterize HBV virion and SVP assembly sites and subsequent transport routes by using in situ cryoEM and other microscopy approaches. Key results from these studies will be validated as much as possible in primary tissues and authentic cell culture models in close collaboration with Thimme, Protzer/Wettengel, Urban/Nkongolo, Dao Thi and Z02.

In conclusion, this project will provide important novel insights into the regulation of the IFN response by LGP2 as well as HBV-host cell interaction with possible implications for novel approaches to enhance anti-viral immunity aiming at functional cure of chronic hepatitis B.