• ABHD5/CGI-58, the Chanarin-Dorfman Syndrome Protein, Mobilises Lipid Stores for Hepatitis C Virus Production.

      Vieyres, Gabrielle; Welsch, Kathrin; Gerold, Gisa; Gentzsch, Juliane; Kahl, Sina; Vondran, Florian W R; Kaderali, Lars; Pietschmann, Thomas; Twincore Centre for Experimental and Clinical Infection Research, Hannover, Germany. (2016-04)
      Hepatitis C virus (HCV) particles closely mimic human very-low-density lipoproteins (VLDL) to evade humoral immunity and to facilitate cell entry. However, the principles that govern HCV association with VLDL components are poorly defined. Using an siRNA screen, we identified ABHD5 (α/β hydrolase domain containing protein 5, also known as CGI-58) as a new host factor promoting both virus assembly and release. ABHD5 associated with lipid droplets and triggered their hydrolysis. Importantly, ABHD5 Chanarin-Dorfman syndrome mutants responsible for a rare lipid storage disorder in humans were mislocalised, and unable to consume lipid droplets or support HCV production. Additional ABHD5 mutagenesis revealed a novel tribasic motif that does not influence subcellular localization but determines both ABHD5 lipolytic and proviral properties. These results indicate that HCV taps into the lipid droplet triglyceride reservoir usurping ABHD5 lipase cofactor function. They also suggest that the resulting lipid flux, normally devoted to VLDL synthesis, also participates in the assembly and release of the HCV lipo-viro-particle. Altogether, our study provides the first association between the Chanarin-Dorfman syndrome protein and an infectious disease and sheds light on the hepatic manifestations of this rare genetic disorder as well as on HCV morphogenesis.
    • Adaptation of hepatitis C virus to mouse CD81 permits infection of mouse cells in the absence of human entry factors.

      Bitzegeio, Julia; Bankwitz, Dorothea; Hueging, Kathrin; Haid, Sibylle; Brohm, Christiane; Zeisel, Mirjam B; Herrmann, Eva; Iken, Marcus; Ott, Michael; Baumert, Thomas F; et al. (2010)
      Hepatitis C virus (HCV) naturally infects only humans and chimpanzees. The determinants responsible for this narrow species tropism are not well defined. Virus cell entry involves human scavenger receptor class B type I (SR-BI), CD81, claudin-1 and occludin. Among these, at least CD81 and occludin are utilized in a highly species-specific fashion, thus contributing to the narrow host range of HCV. We adapted HCV to mouse CD81 and identified three envelope glycoprotein mutations which together enhance infection of cells with mouse or other rodent receptors approximately 100-fold. These mutations enhanced interaction with human CD81 and increased exposure of the binding site for CD81 on the surface of virus particles. These changes were accompanied by augmented susceptibility of adapted HCV to neutralization by E2-specific antibodies indicative of major conformational changes of virus-resident E1/E2-complexes. Neutralization with CD81, SR-BI- and claudin-1-specific antibodies and knock down of occludin expression by siRNAs indicate that the adapted virus remains dependent on these host factors but apparently utilizes CD81, SR-BI and occludin with increased efficiency. Importantly, adapted E1/E2 complexes mediate HCV cell entry into mouse cells in the absence of human entry factors. These results further our knowledge of HCV receptor interactions and indicate that three glycoprotein mutations are sufficient to overcome the species-specific restriction of HCV cell entry into mouse cells. Moreover, these findings should contribute to the development of an immunocompetent small animal model fully permissive to HCV.
    • Adaptation of Stenotrophomonas maltophilia in cystic fibrosis: molecular diversity, mutation frequency and antibiotic resistance.

      Vidigal, P G; Dittmer, S; Steinmann, E; Buer, J; Rath, P-M; Steinmann, J (2014-07)
      Due to the continuous exposure to a challenging environment and repeated antibiotic treatment courses, bacterial populations in cystic fibrosis (CF) patients experience selective pressure causing the emergence of mutator phenotypes. In this study we investigated the genotypic diversity, mutation frequency and antibiotic resistance of S. maltophilia isolates chronically colonizing CF patients. S. maltophilia was isolated from a total of 90 sputum samples, collected sequentially from 19 CF patients admitted between January 2008 and March 2012 at the University Hospital Essen, Germany. DNA fingerprinting by repetitive-sequence-based PCR revealed that 68.4% (n=13) of CF patients harbored different S. maltophilia genotypes during the 4-year study course. Out of 90 S. maltophilia isolates obtained from chronically colonized CF patients, 17.8% (n=16) were hypomutators, 27.7% (n=25), normomutators, 23.3% (n=21), weak hypermutators and 31.2% (n=28) strong hypermutators. We also found that mutation rates of the most clonally related genotypes varied over time with the tendency to become less mutable. Mutator isolates were found to have no significant increase in resistance against eight different antibiotics versus nonmutators. Sequencing of the mismatch repair genes mutL, mutS and uvrD revealed alterations that resulted in amino acid changes in their corresponding proteins. Here, we could demonstrate that several different S. maltophilia genotypes are present in CF patients and as a sign of adaption their mutation status switches over time to a less mutator phenotype without increasing resistance. These results suggest that S. maltophilia attempts to sustain its biological fitness as mechanism for long-term persistence in the CF lung.
    • An alpaca nanobody inhibits hepatitis C virus entry and cell-to-cell transmission.

      Tarr, Alexander W; Lafaye, Pierre; Meredith, Luke; Damier-Piolle, Laurence; Urbanowicz, Richard A; Meola, Annalisa; Jestin, Jean-Luc; Brown, Richard J P; McKeating, Jane A; Rey, Felix A; et al. (2013-09)
      Severe liver disease caused by chronic hepatitis C virus is the major indication for liver transplantation. Despite recent advances in antiviral therapy, drug toxicity and unwanted side effects render effective treatment in liver-transplanted patients a challenging task. Virus-specific therapeutic antibodies are generally safe and well-tolerated, but their potential in preventing and treating hepatitis C virus (HCV) infection has not yet been realized due to a variety of issues, not least high production costs and virus variability. Heavy-chain antibodies or nanobodies, produced by camelids, represent an exciting antiviral approach; they can target novel highly conserved epitopes that are inaccessible to normal antibodies, and they are also easy to manipulate and produce. We isolated four distinct nanobodies from a phage-display library generated from an alpaca immunized with HCV E2 glycoprotein. One of them, nanobody D03, recognized a novel epitope overlapping with the epitopes of several broadly neutralizing human monoclonal antibodies. Its crystal structure revealed a long complementarity determining region (CD3) folding over part of the framework that, in conventional antibodies, forms the interface between heavy and light chain. D03 neutralized a panel of retroviral particles pseudotyped with HCV glycoproteins from six genotypes and authentic cell culture-derived particles by interfering with the E2-CD81 interaction. In contrast to some of the most broadly neutralizing human anti-E2 monoclonal antibodies, D03 efficiently inhibited HCV cell-to-cell transmission. Conclusion: This is the first description of a potent and broadly neutralizing HCV-specific nanobody representing a significant advance that will lead to future development of novel entry inhibitors for the treatment and prevention of HCV infection and help our understanding of HCV cell-to-cell transmission.
    • Anti-infective properties of epigallocatechin-3-gallate (EGCG), a component of green tea.

      Steinmann, J; Buer, J; Pietschmann, T; Steinmann, E; Institute of Medical Microbiology, University Hospital Essen, University of Duisburg-Essen, Essen, Germany. joerg.steinmann@uk-essen.de (2013-03)
      The consumption of green tea (Camellia sinensis) has been shown to have many physiological and pharmacological health benefits. In the past two decades several studies have reported that epigallocatechin-3-gallate (EGCG), the main constituent of green tea, has anti-infective properties. Antiviral activities of EGCG with different modes of action have been demonstrated on diverse families of viruses, such as Retroviridae, Orthomyxoviridae and Flaviviridae and include important human pathogens like human immunodeficiency virus, influenza A virus and the hepatitis C virus. Furthermore, the molecule interferes with the replication cycle of DNA viruses like hepatitis B virus, herpes simplex virus and adenovirus. Most of these studies demonstrated antiviral properties within physiological concentrations of EGCG in vitro. In contrast, the minimum inhibitory concentrations against bacteria were 10-100-fold higher. Nevertheless, the antibacterial effects of EGCG alone and in combination with different antibiotics have been intensively analysed against a number of bacteria including multidrug-resistant strains such as methicillin-resistant Staphylococcus aureus or Stenotrophomonas maltophilia. Furthermore, the catechin EGCG has antifungal activity against human-pathogenic yeasts like Candida albicans. Although the mechanistic effects of EGCG are not fully understood, there are results indicating that EGCG binds to lipid membranes and affects the folic acid metabolism of bacteria and fungi by inhibiting the cytoplasmic enzyme dihydrofolate reductase. This review summarizes the current knowledge and future perspectives on the antibacterial, antifungal and antiviral effects of the green tea constituent EGCG.
    • Anti-infective Properties of the Golden Spice Curcumin.

      Praditya, Dimas; Kirchhoff, Lisa; Brüning, Janina; Rachmawati, Heni; Steinmann, Joerg; Steinmann, Eike; TWINCORE, Zentrum für experimentelle und klinische Infektionsforschung GmbH,Feodor-Lynen Str. 7, 30625 Hannover, Germany. (Frontiers, 2019-01-01)
      The search for novel anti-infectives is one of the most important challenges in natural product research, as diseases caused by bacteria, viruses, and fungi are influencing the human society all over the world. Natural compounds are a continuing source of novel anti-infectives. Accordingly, curcumin, has been used for centuries in Asian traditional medicine to treat various disorders. Numerous studies have shown that curcumin possesses a wide spectrum of biological and pharmacological properties, acting, for example, as anti-inflammatory, anti-angiogenic and anti-neoplastic, while no toxicity is associated with the compound. Recently, curcumin's antiviral and antibacterial activity was investigated, and it was shown to act against various important human pathogens like the influenza virus, hepatitis C virus, HIV and strains of Staphylococcus, Streptococcus, and Pseudomonas. Despite the potency, curcumin has not yet been approved as a therapeutic antiviral agent. This review summarizes the current knowledge and future perspectives of the antiviral, antibacterial, and antifungal effects of curcumin.
    • Antiviral Actions of 25-Hydroxycholesterol in Fish Vary With the Virus-Host Combination.

      Adamek, Mikolaj; Davies, Jonathan; Beck, Alexander; Jordan, Lisa; Becker, Anna M; Mojzesz, Miriam; Rakus, Krzysztof; Rumiac, Typhaine; Collet, Bertrand; Brogden, Graham; et al. (Frontiers, 2021-02-24)
      Cholesterol is essential for building and maintaining cell membranes and is critical for several steps in the replication cycle of viruses, especially for enveloped viruses. In mammalian cells virus infections lead to the accumulation of the oxysterol 25-hydroxycholesterol (25HC), an antiviral factor, which is produced from cholesterol by the cholesterol 25 hydroxylase (CH25H). Antiviral responses based on CH25H are not well studied in fish. Therefore, in the present study putative genes encoding for CH25H were identified and amplified in common carp and rainbow trout cells and an HPLC-MS method was applied for determination of oxysterol concentrations in these cells under virus infection. Our results give some evidence that the activation of CH25H could be a part of the antiviral response against a broad spectrum of viruses infecting fish, in both common carp and rainbow trout cells in vitro. Quantification of oxysterols showed that fibroblastic cells are capable of producing 25HC and its metabolite 7α,25diHC. The oxysterol 25HC showed an antiviral activity by blocking the entry of cyprinid herpesvirus 3 (CyHV-3) into KFC cells, but not spring viremia of carp virus (SVCV) or common carp paramyxovirus (Para) in the same cells, or viral haemorrhagic septicaemia virus (VHSV) and infectious pancreatic necrosis virus (IPNV) into RTG-2 cells. Despite the fact that the CH25H based antiviral response coincides with type I IFN responses, the stimulation of salmonid cells with recombinant type I IFN proteins from rainbow trout could not induce ch25h_b gene expression. This provided further evidence, that the CH25H-response is not type I IFN dependent. Interestingly, the susceptibility of CyHV-3 to 25HC is counteracted by a downregulation of the expression of the ch25h_b gene in carp fibroblasts during CyHV-3 infection. This shows a unique interplay between oxysterol based immune responses and immunomodulatory abilities of certain viruses.
    • Antiviral Meroterpenoid Rhodatin and Sesquiterpenoids Rhodocoranes A-E from the Wrinkled Peach Mushroom, Rhodotus palmatus.

      Sandargo, Birthe; Michehl, Maira; Praditya, Dimas; Steinmann, Eike; Stadler, Marc; Surup, Frank; HZI,Helmholtz-Zentrum für Infektionsforschung GmbH, Inhoffenstr. 7,38124 Braunschweig, Germany; TWINCORE, Zentrum für experimentelle und klinische Infektionsforschung GmbH,Feodor-Lynen Str. 7, 30625 Hannover, Germany. (American Chemical Society, 2019-05-03)
      Rhodatin (1), a meroterpenoid featuring a unique pentacyclic scaffold with both spiro and spiroketal centers, and five unusual acorane-type sesquiterpenoids, named rhodocoranes A-E (2-6, respectively), are the first natural products isolated from the basidiomycete Rhodotus palmatus. Their structures were elucidated by two-dimensional NMR experiments and HRESIMS, while the absolute configuration of the substance family was determined by Mosher's method utilizing 2. Rhodatin strongly inhibited hepatitis C virus, whereas 4 displayed cytotoxicity and selective antifungal activity.
    • Assessment of cross-species transmission of hepatitis C virus-related non-primate hepacivirus in a population of humans at high risk of exposure.

      Pfaender, Stephanie; Walter, Stephanie; Todt, Daniel; Behrendt, Patrick; Doerrbecker, Juliane; Wölk, Benno; Engelmann, Michael; Gravemann, Ute; Seltsam, Axel; Steinmann, Joerg; et al. (2015-09)
      The recent discovery of hepatitis C virus (HCV)-related viruses in different animal species has raised new speculations regarding the origin of HCV and the possibility of a zoonotic source responsible for the endemic HCV transmission. As a consequence, these new findings prompt questions regarding the potential for cross-species transmissions of hepaciviruses. The closest relatives to HCV discovered to date are the non-primate hepaciviruses (NPHVs), which have been described to infect horses. To evaluate the risk of a potential zoonotic transmission, we analysed NPHV RNA and antibodies in humans with occupational exposure to horses in comparison with a low-risk group. Both groups were negative for NPHV RNA, even though low seroreactivities against various NPHV antigens could be detected irrespective of the group. In conclusion, we did not observe evidence of NPHV transmission between horses and humans.
    • The ATGL lipase cooperates with ABHD5 to mobilize lipids for hepatitis C virus assembly.

      Vieyres, Gabrielle; Reichert, Isabelle; Carpentier, Arnaud; Vondran, Florian W R; Pietschmann, Thomas; TWINCORE, Zentrum für experimentelle und klinische Infektionsforschung GmbH,Feodor-Lynen Str. 7, 30625 Hannover, Germany. (PLOS, 2020-06-15)
      Lipid droplets are essential cellular organelles for storage of fatty acids and triglycerides. The hepatitis C virus (HCV) translocates several of its proteins onto their surface and uses them for production of infectious progeny. We recently reported that the lipid droplet-associated α/β hydrolase domain-containing protein 5 (ABHD5/CGI-58) participates in HCV assembly by mobilizing lipid droplet-associated lipids. However, ABHD5 itself has no lipase activity and it remained unclear how ABHD5 mediates lipolysis critical for HCV assembly. Here, we identify adipose triglyceride lipase (ATGL) as ABHD5 effector and new host factor involved in the hepatic lipid droplet degradation as well as in HCV and lipoprotein morphogenesis. Modulation of ATGL protein expression and lipase activity controlled lipid droplet lipolysis and virus production. ABHD4 is a paralog of ABHD5 unable to activate ATGL or support HCV assembly and lipid droplet lipolysis. Grafting ABHD5 residues critical for activation of ATGL onto ABHD4 restored the interaction between lipase and co-lipase and bestowed the pro-viral and lipolytic functions onto the engineered protein. Congruently, mutation of the predicted ABHD5 protein interface to ATGL ablated ABHD5 functions in lipid droplet lipolysis and HCV assembly. Interestingly, minor alleles of ABHD5 and ATGL associated with neutral lipid storage diseases in human, are also impaired in lipid droplet lipolysis and their pro-viral functions. Collectively, these results show that ABHD5 cooperates with ATGL to mobilize triglycerides for HCV infectious virus production. Moreover, viral manipulation of lipid droplet homeostasis via the ABHD5-ATGL axis, akin to natural genetic variation in these proteins, emerges as a possible mechanism by which chronic HCV infection causes liver steatosis.
    • Axl can serve as entry factor for Lassa virus depending on the functional glycosylation of dystroglycan.

      Fedeli, Chiara; Torriani, Giulia; Galan-Navarro, Clara; Moraz, Marie-Laurence; Moreno, Hector; Gerold, Gisa; Kunz, Stefan; Helmholtz-Zentrum für Infektionsforschung GmbH, Inhoffenstr. 7, 38124 Braunschweig, Germany. (2017-12-13)
      Fatal infection with the highly pathogenic Lassa virus (LASV) is characterized by extensive viral dissemination, indicating broad tissue tropism. The major cellular receptor for LASV is the highly conserved extracellular matrix receptor dystroglycan (DG). Binding of LASV depends on DG's tissue-specific post-translational modification with the unusual O-linked polysaccharide matriglycan. Interestingly, functional glycosylation of DG does not always correlate with viral tropism observed in vivo The broadly expressed phosphatidylserine (PS) receptors Axl and Tyro3 were recently identified as alternative LASV receptor candidates. However, their role in LASV entry is not entirely understood. Here we examined LASV receptor candidates in primary human cells and found co-expression of Axl with differentially glycosylated DG. To study LASV receptor use in the context of productive arenavirus infection, we employed recombinant lymphocytic choriomeningitis virus expressing LASV glycoprotein (rLCMV-LASVGP) as validated BSL2 model. We confirm and extend previous work, showing that Axl can contribute to LASV entry in absence of functional DG using "apoptotic mimicry", similar to other enveloped virus. We further show that Axl-dependent LASV entry requires receptor activation and involves a pathway resembling macropinocytosis. Axl-mediated LASV entry is facilitated by heparan sulfate and critically depends on the late endosomal protein LAMP-1 as intracellular entry factor. In endothelial cells expressing low levels of functional DG, both receptors are engaged by the virus and can contribute to productive entry. In sum, we characterize the role of Axl in LASV entry and provide a rationale to target Axl in anti-viral therapy.IMPORTANCEThe highly pathogenic arenavirus Lassa (LASV) represents a serious public health problem in Africa. Although the principal LASV receptor dystroglycan (DG) is ubiquitously expressed, virus binding critically depends on DG's post-translational modification, which does not always correlate with tissue tropism. The broadly expressed phosphatidylserine receptor Axl was recently identified as alternative LASV receptor candidate, but its role in LASV entry is unclear. Here we investigated the exact role of Axl in LASV entry as a function of DG's post-translational modification. We found that in absence of functional DG, Axl can mediate LASV entry via "apoptotic mimicry". Productive entry requires virus-induced receptor activation, involves macropinocytosis, and critically depends on LAMP-1. In endothelial cells that express low levels of glycosylated DG, both receptors can promote LASV entry. In sum, our study defines the roles of Axl in LASV entry and provides a rationale to target Axl in anti-viral therapy.
    • Bile Acids Specifically Increase Hepatitis C Virus RNA-Replication.

      Chhatwal, Patrick; Bankwitz, Dorothea; Gentzsch, Juliane; Frentzen, Anne; Schult, Philipp; Lohmann, Volker; Pietschmann, Thomas; Department of Experimental Virology, TWINCORE, Centre for Experimental and Clinical Infection Research; a joint venture between the Medical School Hannover and the Helmholtz Centre for Infection Research, Hannover, Germany. (2012)
      Hepatitis C virus (HCV) patients with high serum levels of bile acids (BAs) respond poorly to IFN therapy. BAs have been shown to increase RNA-replication of genotype 1 but not genotype 2a replicons. Since BAs modulate lipid metabolism including lipoprotein secretion and as HCV depends on lipids and lipoproteins during RNA-replication, virus production and cell entry, BAs may affect multiple steps of the HCV life cycle. Therefore, we analyzed the influence of BAs on individual steps of virus replication.
    • Biotechnological Potential of Bacteria Isolated from the Sea Cucumber and from Lampung, Indonesia.

      Wibowo, Joko T; Kellermann, Matthias Y; Versluis, Dennis; Putra, Masteria Y; Murniasih, Tutik; Mohr, Kathrin I; Wink, Joachim; Engelmann, Michael; Praditya, Dimas F; Steinmann, Eike; et al. (MPDI, 2019-11-08)
      In order to minimize re-discovery of already known anti-infective compounds, we focused our screening approach on understudied, almost untapped marine environments including marine invertebrates and their associated bacteria. Therefore, two sea cucumber species, Holothuria leucospilota and Stichopus vastus, were collected from Lampung (Indonesia), and 127 bacterial strains were identified by partial 16S rRNA-gene sequencing analysis and compared with the NCBI database. In addition, the overall bacterial diversity from tissue samples of the sea cucumbers H. leucospilota and S. vastus was analyzed using the cultivation-independent Illumina MiSEQ analysis. Selected bacterial isolates were grown to high densities and the extracted biomass was tested against a selection of bacteria and fungi as well as the hepatitis C virus (HCV). Identification of putative bioactive bacterial-derived compounds were performed by analyzing the accurate mass of the precursor/parent ions (MS1) as well as product/daughter ions (MS2) using high resolution mass spectrometry (HRMS) analysis of all active fractions. With this attempt we were able to identify 23 putatively known and two previously unidentified precursor ions. Moreover, through 16S rRNA-gene sequencing we were able to identify putatively novel bacterial species from the phyla Actinobacteria, Proteobacteria and also Firmicutes. Our findings suggest that sea cucumbers like H. leucospilota and S. vastus are promising sources for the isolation of novel bacterial species that produce compounds with potentially high biotechnological potential.
    • CD81 Receptor Regions outside the Large Extracellular Loop Determine Hepatitis C Virus Entry into Hepatoma Cells.

      Banse, Pia; Moeller, Rebecca; Bruening, Janina; Lasswitz, Lisa; Kahl, Sina; Khan, Abdul G; Marcotrigiano, Joseph; Pietschmann, Thomas; Gerold, Gisa; TWINCORE, Zentrum für experimentelle und klinischeInfektionsforschung GmbH, Feodor-Lynen-Str. 7, 30625 Hannover, Germany. (2018)
      Hepatitis C virus (HCV) enters human hepatocytes using four essential entry factors, one of which is human CD81 (hCD81). The tetraspanin hCD81 contains a large extracellular loop (LEL), which interacts with the E2 glycoprotein of HCV. The role of the non-LEL regions of hCD81 (intracellular tails, four transmembrane domains, small extracellular loop and intracellular loop) is poorly understood. Here, we studied the contribution of these domains to HCV susceptibility of hepatoma cells by generating chimeras of related tetraspanins with the hCD81 LEL. Our results show that non-LEL regions in addition to the LEL determine susceptibility of cells to HCV. While closely related tetraspanins (X. tropicalis CD81 and D. rerio CD81) functionally complement hCD81 non-LEL regions, distantly related tetraspanins (C. elegans TSP9 amd D. melanogaster TSP96F) do not and tetraspanins with intermediate homology (hCD9) show an intermediate phenotype. Tetraspanin homology and susceptibility to HCV correlate positively. For some chimeras, infectivity correlates with surface expression. In contrast, the hCD9 chimera is fully surface expressed, binds HCV E2 glycoprotein but is impaired in HCV receptor function. We demonstrate that a cholesterol-coordinating glutamate residue in CD81, which hCD9 lacks, promotes HCV infection. This work highlights the hCD81 non-LEL regions as additional HCV susceptibility-determining factors.
    • Cell culture systems for hepatitis C virus.

      Steinmann, Eike; Pietschmann, Thomas; Helmholtz Centre for Infection Research, Hannover, Germany. (2013)
      Due to the obligatory intracellular lifestyle of viruses, cell culture systems for efficient viral propagation are crucial to obtain a detailed understanding of the virus-host cell interaction. For hepatitis C virus (HCV) the development of permissive and authentic culture models continues to be a challenging task. The first efforts to culture HCV had limited success and range back to before the virus was molecularly cloned in 1989. Since then several major breakthroughs have gradually overcome limitations in culturing the virus and sequentially permitted analysis of viral RNA replication, cell entry, and ultimately the complete replication cycle in cultured cells in 2005. Until today, basic and applied HCV research greatly benefit from these tremendous efforts which spurred multiple complementary cell-based model systems for distinct steps of the HCV replication cycle. When used in combination they now permit deep insights into the fascinating biology of HCV and its interplay with the host cell. In fact, drug development has been much facilitated and our understanding of the molecular determinants of HCV replication has grown in parallel to these advances. Building on this groundwork and further refining our cellular models to better mimic the architecture, polarization and differentiation of natural hepatocytes should reveal novel unique aspects of HCV replication. Ultimately, models to culture primary HCV isolates across all genotypes may teach us important new lessons about viral functional adaptations that have evolved in exchange with its human host and that may explain the variable natural course of hepatitis C.
    • Cell culture-derived HCV cannot infect synovial fibroblasts.

      Nadeem, Abd-Elshafy D; Thomas, Pietschmann; Ulf, Müller-Ladner; Elena, Neumann; Anggakusuma; Mohamed, Bahgat M; Frank, Pessler; Patrick, Behrendt; TWINCORE, Centre for Experimental and Clinical Infection Research GmbH, Feodor-Lynen-Str. 3-7, 30625 Hannover, Germany. (2015)
      Worldwide 170 million individuals are infected with hepatitis C virus (HCV), up to 45 million of whom are affected by arthropathy. It is unclear whether this is due to viral infection of synovial cells or immune-mediated mechanisms. We tested the capacity of primary synovial fibroblasts to support HCV propagation. Out of the four critical HCV receptors, only CD81 was expressed to any significant extent in OASF and RASF. Consistent with this, pseudotyped HCV particles were unable to infect these cells. Permissiveness for HCV replication was investigated by transfecting cells with a subgenomic replicon of HCV encoding a luciferase reporter. OASF and RASF did not support replication of HCV, possibly due to low expression levels of miR-122. In conclusion, primary human synovial fibroblasts are unable to support propagation of HCV in vitro. HCV-related arthropathy is unlikely due to direct infection of these cells.
    • A central hydrophobic E1 region controls the pH range of hepatitis C virus membrane fusion and susceptibility to fusion inhibitors.

      Banda, Dominic H; Perin, Paula M; Brown, Richard J P; Todt, Daniel; Solodenko, Wladimir; Hoffmeyer, Patrick; Kumar Sahu, Kamlesh; Houghton, Michael; Meuleman, Philip; Müller, Rolf; et al. (Elsevier, 2019-06-01)
    • Characterization of Equine Parvovirus in Thoroughbred Breeding Horses from Germany.

      Meister, Toni Luise; Tegtmeyer, Birthe; Brüggemann, Yannick; Sieme, Harald; Feige, Karsten; Todt, Daniel; Stang, Alexander; Cavalleri, Jessika-M V; Steinmann, Eike; TWINCORE, Zentrum für experimentelle und klinische Infektionsforschung GmbH,Feodor-Lynen Str. 7, 30625 Hannover, Germany. (MPDI, 2019-10-18)
    • Characterization of the inhibition of hepatitis C virus entry by in vitro-generated and patient-derived oxidized low-density lipoprotein.

      Westhaus, Sandra; Bankwitz, Dorothea; Ernst, Stefanie; Rohrmann, Katrin; Wappler, Ilka; Agné, Clemens; Luchtefeld, Maren; Schieffer, Bernhard; Sarrazin, Christoph; Manns, Michael P; et al. (2013-05)
      Oxidized low-density lipoprotein (oxLDL) has been reported as an inhibitor of hepatitis C virus (HCV) cell entry, making it the only known component of human lipid metabolism with an antiviral effect on HCV. However, several questions remain open, including its effect on full-length cell-culture-grown HCV (HCVcc) of different genotypes or on other steps of the viral replication cycle, its mechanism of action, and whether endogenous oxLDL shares the anti-HCV properties of in vitro-generated oxLDL. We combined molecular virology tools with oxLDL serum measurements in different patient cohorts to address these questions. We found that oxLDL inhibits HCVcc at least as potently as HCV pseudoparticles. There was moderate variation between genotypes, with genotype 4 appearing the most oxLDL sensitive. Intracellular RNA replication and assembly and release of new particles were unaffected. HCV particles entering target cells lost oxLDL sensitivity with time kinetics parallel to anti-SR-BI (scavenger receptor class B type I), but significantly earlier than anti-CD81, suggesting that oxLDL acts by perturbing interaction between HCV and SR-BI. Finally, in chronically HCV-infected individuals, endogenous serum oxLDL levels did not correlate with viral load, but in HCV-negative sera, high endogenous oxLDL had a negative effect on HCV infectivity in vitro. Conclusion: oxLDL is a potent pangenotype HCV entry inhibitor that maintains its activity in the context of human serum and targets an early step of HCV entry.
    • Chronic equine hepacivirus infection in an adult gelding with severe hepatopathy.

      Tegtmeyer, Birthe; Echelmeyer, Julia; Pfankuche, Vanessa M; Puff, Christina; Todt, Daniel; Fischer, Nicole; Durham, Andy; Feige, Karsten; Baumgärtner, Wolfgang; Steinmann, Eike; et al. (Wiley Open Access, 2019-01-01)
      Background: Equine hepacivirus (EqHV) in equids represents the closest homologue to hepatitis C virus(HCV) infecting humans. A majority of HCV infected patients develop a chronic course of infection leading toliver fibrosis, cirrhosis and liver failure. However, in horses mostly transient mild subclinical infections arereported for EqHV to date. Objectives: EqHV can be involved in chronic liver diseases of horses. Methods:Biochemical parameters in serum samples were measured. Viral load was determined using qPCR. Next gener-ation sequencing (NGS) of serum was performed. Liver tissue was stained with haematoxylin and eosin andanalysed for viral RNA with fluorescentin situ-hybridization. Results: The horse showed symptoms of severehepatopathy and was chronically infected with EqHV. Viral RNA was detectable in the liver during disease.To rule out other infectious agents NGS was performed and showed the highest abundance for EqHV. Theidentified virus sequence was similar to other circulating equine hepaciviruses. Conclusions: EqHV can be asso-ciated with liver disease in horses. Whether it causes the disease or contributes in a multifactorial mannerneeds further investigation