| 1. |
- Alberione, Maria Pia, et al.
(författare)
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Single-nucleotide variants in human CD81 influence hepatitis C virus infection of hepatoma cells
- 2020
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Ingår i: Medical Microbiology and Immmunology. - : Springer. - 0300-8584 .- 1432-1831. ; 209:4, s. 499-514
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Tidskriftsartikel (refereegranskat)abstract
- An estimated number of 71 million people are living with chronic hepatitis C virus (HCV) infection worldwide and 400,000 annual deaths are related to the infection. HCV entry into the hepatocytes is complex and involves several host factors. The tetraspanin human CD81 (hCD81) is one of the four essential entry factors and is composed of one large extracellular loop, one small extracellular loop, four transmembrane domains, one intracellular loop and two intracellular tails. The large extracellular loop interacts with the E2 glycoprotein of HCV. Regions outside the large extracellular loop (backbone) of hCD81 have a critical role in post-binding entry steps and determine susceptibility of hepatocytes to HCV. Here, we investigated the effect of five non-synonymous single-nucleotide variants in the backbone of hCD81 on HCV susceptibility. We generated cell lines that stably express the hCD81 variants and infected the cells using HCV pseudoparticles and cell culture-derived HCV. Our results show that all the tested hCD81 variants support HCV pseudoparticle entry with similar efficiency as wild-type hCD81. In contrast, variants A54V, V211M and M220I are less supportive to cell culture-derived HCV infection. This altered susceptibility is HCV genotype dependent and specifically affected the cell entry step. Our findings identify three hCD81 genetic variants that are impaired in their function as HCV host factors for specific viral genotypes. This study provides additional evidence that genetic host variation contributes to inter-individual differences in HCV infection and outcome.
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| 2. |
- Banse, Pia, et al.
(författare)
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CD81 receptor regions outside the large extracellular loop determine hepatitis C virus entry into hepatoma cells
- 2018
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Ingår i: Viruses. - : MDPI AG. - 1999-4915. ; 10:4
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Tidskriftsartikel (refereegranskat)abstract
- 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.
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| 3. |
- Becker, Miriam, et al.
(författare)
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Efficient clathrin-mediated entry of enteric adenoviruses in human duodenal cells
- 2023
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Ingår i: Journal of Virology. - 0022-538X .- 1098-5514. ; 97:10
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Tidskriftsartikel (refereegranskat)abstract
- Enteric adenovirus types F40 and 41 (EAdVs) are a leading cause of diarrhea and diarrhea-associated death in young children and have recently been proposed to cause acute hepatitis in children. EAdVs have a unique capsid architecture and exhibit — unlike other human adenoviruses — a relatively strict tropism for gastrointestinal tissues with, to date, understudied infection mechanism and unknown target cells. In this study, we turn to potentially limiting host factors by comparing EAdV entry in cell lines with respiratory and intestinal origin by cellular perturbation, virus particle tracking, and transmission electron microscopy. Our analyses highlight kinetic advantages for EAdVs in duodenal HuTu80 cell infection and reveal a larger fraction of mobile particles, faster virus uptake, and infectious particle entry in intestinal cells. Moreover, EAdVs display a dependence on clathrin- and dynamin-dependent pathways in intestinal cells. Detailed knowledge of virus entry routes and host factor requirements is essential to understanding pathogenesis and developing new countermeasures. Hence, this study provides novel insights into the entry mechanisms of a medically important virus with emerging tropism in a cell line originating from a relevant tissue. IMPORTANCE Enteric adenoviruses have historically been difficult to grow in cell culture, which has resulted in lack of knowledge of host factors and pathways required for infection of these medically relevant viruses. Previous studies in non-intestinal cell lines showed slow infection kinetics and generated comparatively low virus yields compared to other adenovirus types. We suggest duodenum-derived HuTu80 cells as a superior cell line for studies to complement efforts using complex intestinal tissue models. We show that viral host cell factors required for virus entry differ between cell lines from distinct origins and demonstrate the importance of clathrin-mediated endocytosis.
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| 4. |
- Bley, Hanna, et al.
(författare)
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Proximity labeling of host factor ANXA3 in HCV infection reveals a novel LARP1 function in viral entry
- 2024
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Ingår i: Journal of Biological Chemistry. - : Elsevier. - 0021-9258 .- 1083-351X. ; 300:5
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Tidskriftsartikel (refereegranskat)abstract
- Hepatitis C virus (HCV) infection is tightly connected to the lipid metabolism with lipid droplets (LDs) serving as assembly sites for progeny virions. A previous LD proteome analysis identified annexin A3 (ANXA3) as an important HCV host factor that is enriched at LDs in infected cells and required for HCV morphogenesis. To further characterize ANXA3 function in HCV, we performed proximity labeling using ANXA3-BioID2 as bait in HCV-infected cells. Two of the top proteins identified proximal to ANXA3 during HCV infection were the La-related protein 1 (LARP1) and the ADP ribosylation factor-like protein 8B (ARL8B), both of which have been previously described to act in HCV particle production. In follow-up experiments, ARL8B functioned as a pro-viral HCV host factor without localizing to LDs and thus likely independent of ANXA3. In contrast, LARP1 interacts with HCV core protein in an RNA-dependent manner and is translocated to LDs by core protein. Knockdown of LARP1 decreased HCV spreading without altering HCV RNA replication or viral titers. Unexpectedly, entry of HCV particles and E1/E2-pseudotyped lentiviral particles was reduced by LARP1 depletion, whereas particle production was not altered. Using a recombinant vesicular stomatitis virus (VSV)ΔG entry assay, we showed that LARP1 depletion also decreased entry of VSV with VSV, MERS, and CHIKV glycoproteins. Therefore, our data expand the role of LARP1 as an HCV host factor that is most prominently involved in the early steps of infection, likely contributing to endocytosis of viral particles through the pleiotropic effect LARP1 has on the cellular translatome.
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| 5. |
- Brown, Richard J. P., et al.
(författare)
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Liver-expressed Cd302 and Cr1l limit hepatitis C virus cross-species transmission to mice
- 2020
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Ingår i: Science Advances. - : American Association for the Advancement of Science. - 2375-2548. ; 6:45
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Tidskriftsartikel (refereegranskat)abstract
- Hepatitis C virus (HCV) has no animal reservoir, infecting only humans. To investigate species barrier determinants limiting infection of rodents, murine liver complementary DNA library screening was performed, identifying transmembrane proteins Cd302 and Cr1l as potent restrictors of HCV propagation. Combined ectopic expression in human hepatoma cells impeded HCV uptake and cooperatively mediated transcriptional dysregulation of a noncanonical program of immunity genes. Murine hepatocyte expression of both factors was constitutive and not interferon inducible, while differences in liver expression and the ability to restrict HCV were observed between the murine orthologs and their human counterparts. Genetic ablation of endogenous Cd302 expression in human HCV entry factor transgenic mice increased hepatocyte permissiveness for an adapted HCV strain and dysregulated expression of metabolic process and host defense genes. These findings highlight human-mouse differences in liver-intrinsic antiviral immunity and facilitate the development of next-generation murine models for preclinical testing of HCV vaccine candidates.
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| 6. |
- Bruening, Janina, et al.
(författare)
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Hepatitis C virus enters liver cells using the CD81 receptor complex proteins calpain-5 and CBLB
- 2018
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Ingår i: PLoS Pathogens. - : Public Library of Science (PLoS). - 1553-7366 .- 1553-7374. ; 14:7
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Tidskriftsartikel (refereegranskat)abstract
- Hepatitis C virus (HCV) and the malaria parasite Plasmodium use the membrane protein CD81 to invade human liver cells. Here we mapped 33 host protein interactions of CD81 in primary human liver and hepatoma cells using high-resolution quantitative proteomics. In the CD81 protein network, we identified five proteins which are HCV entry factors or facilitators including epidermal growth factor receptor (EGFR). Notably, we discovered calpain-5 (CAPN5) and the ubiquitin ligase Casitas B-lineage lymphoma proto-oncogene B (CBLB) to form a complex with CD81 and support HCV entry. CAPN5 and CBLB were required for a post-binding and pre-replication step in the HCV life cycle. Knockout of CAPN5 and CBLB reduced susceptibility to all tested HCV genotypes, but not to other enveloped viruses such as vesicular stomatitis virus and human coronavirus. Furthermore, Plasmodium sporozoites relied on a distinct set of CD81 interaction partners for liver cell entry. Our findings reveal a comprehensive CD81 network in human liver cells and show that HCV and Plasmodium highjack selective CD81 interactions, including CAPN5 and CBLB for HCV, to invade cells.
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| 7. |
- Bruening, Janina, et al.
(författare)
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The Role of Type III Interferons in Hepatitis C Virus Infection and Therapy
- 2017
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Ingår i: Journal of Immunology Research. - : Hindawi Publishing Corporation. - 2314-8861 .- 2314-7156.
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Tidskriftsartikel (refereegranskat)abstract
- The human interferon (IFN) response is a key innate immune mechanism to fight virus infection. IFNs are host-encoded secreted proteins, which induce IFN-stimulated genes (ISGs) with antiviral properties. Among the three classes of IFNs, type III IFNs, also called IFN lambdas (IFNLs), are an essential component of the innate immune response to hepatitis C virus (HCV). In particular, human polymorphisms in IFNL gene loci correlate with hepatitis C disease progression and with treatment response. To date, the underlying mechanisms remain mostly elusive; however it seems clear that viral infection of the liver induces IFNL responses. As IFNL receptors show a more restricted tissue expression than receptors for other classes of IFNs, IFNL treatment has reduced side effects compared to the classical type I IFN treatment. In HCV therapy, however, IFNL will likely not play an important role as highly effective direct acting antivirals (DAA) exist. Here, we will review our current knowledge on IFNL gene expression, protein properties, signaling, ISG induction, and its implications on HCV infection and treatment. Finally, we will discuss the lessons learnt from the HCV and IFNL field for virus infections beyond hepatitis C.
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| 8. |
- Carriquí-Madroñal, Belén, et al.
(författare)
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Genetic and pharmacological perturbation of hepatitis-C virus entry
- 2023
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Ingår i: Current Opinion in Virology. - : Elsevier. - 1879-6257 .- 1879-6265. ; 62
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Forskningsöversikt (refereegranskat)abstract
- Hepatitis-C virus (HCV) chronically infects 58 million individuals worldwide with variable disease outcome. While a subfraction of individuals exposed to the virus clear the infection, the majority develop chronic infection if untreated. Another subfraction of chronically ill proceeds to severe liver disease. The underlying causes of this interindividual variability include genetic polymorphisms in interferon genes. Here, we review available data on the influence of genetic or pharmacological perturbation of HCV host dependency factors on the clinically observed interindividual differences in disease outcome. We focus on host factors mediating virus entry into human liver cells. We assess available data on genetic variants of the major entry factors scavenger receptor class-B type I, CD81, claudin-1, and occludin as well as pharmacological perturbation of these entry factors. We review cell culture experimental and clinical cohort study data and conclude that entry factor perturbation may contribute to disease outcome of hepatitis C.
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| 9. |
- Carriquí-Madroñal, Belén, et al.
(författare)
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The matrix metalloproteinase ADAM10 supports hepatitis C virus entry and cell-to-cell spread via its sheddase activity
- 2023
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Ingår i: PLoS Pathogens. - : Public Library of Science (PLoS). - 1553-7366 .- 1553-7374. ; 19:11
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Tidskriftsartikel (refereegranskat)abstract
- Hepatitis C virus (HCV) exploits the four entry factors CD81, scavenger receptor class B type I (SR-BI, also known as SCARB1), occludin, and claudin-1 as well as the co-factor epidermal growth factor receptor (EGFR) to infect human hepatocytes. Here, we report that the disintegrin and matrix metalloproteinase 10 (ADAM10) associates with CD81, SR-BI, and EGFR and acts as HCV host factor. Pharmacological inhibition, siRNA-mediated silencing and genetic ablation of ADAM10 reduced HCV infection. ADAM10 was dispensable for HCV replication but supported HCV entry and cell-to-cell spread. Substrates of the ADAM10 sheddase including epidermal growth factor (EGF) and E-cadherin, which activate EGFR family members, rescued HCV infection of ADAM10 knockout cells. ADAM10 did not influence infection with other enveloped RNA viruses such as alphaviruses and a common cold coronavirus. Collectively, our study reveals a critical role for the sheddase ADAM10 as a HCV host factor, contributing to EGFR family member transactivation and as a consequence to HCV uptake.
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| 10. |
- de Diego, J L, et al.
(författare)
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Sensing, presenting, and regulating PAMPs.
- 2007
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Ingår i: Ernst Schering Foundation symposium proceedings. ; :3, s. 83-95
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Tidskriftsartikel (refereegranskat)abstract
- Recognition of microbial infection and initiation of immune responses are controlled by multiple mechanisms. Toll-like receptors (TLRs) are key components of the innate immune system that detect microbial infection. TLR activation helps to eliminate the invading pathogens, coordinate systemic defenses, and initiate adaptive immune responses. Despite progress elucidating the TLR signaling aspects and the physiological relevance of TLRs in microbial infections, the molecular basis of microbial recognition by TLRs is still not fully understood. In this article we focus on the availability of microbial ligands to regulate presentation to TLRs and assist in our understanding of TLR-mediated microbial recognition.
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| 11. |
- Dong, Thi Ngan, et al.
(författare)
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A multitask transfer learning framework for the prediction of virus-human protein–protein interactions
- 2021
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Ingår i: BMC Bioinformatics. - : BioMed Central. - 1471-2105. ; 22:1
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Tidskriftsartikel (refereegranskat)abstract
- Background: Viral infections are causing significant morbidity and mortality worldwide. Understanding the interaction patterns between a particular virus and human proteins plays a crucial role in unveiling the underlying mechanism of viral infection and pathogenesis. This could further help in prevention and treatment of virus-related diseases. However, the task of predicting protein–protein interactions between a new virus and human cells is extremely challenging due to scarce data on virus-human interactions and fast mutation rates of most viruses.Results: We developed a multitask transfer learning approach that exploits the information of around 24 million protein sequences and the interaction patterns from the human interactome to counter the problem of small training datasets. Instead of using hand-crafted protein features, we utilize statistically rich protein representations learned by a deep language modeling approach from a massive source of protein sequences. Additionally, we employ an additional objective which aims to maximize the probability of observing human protein–protein interactions. This additional task objective acts as a regularizer and also allows to incorporate domain knowledge to inform the virus-human protein–protein interaction prediction model.Conclusions: Our approach achieved competitive results on 13 benchmark datasets and the case study for the SARS-CoV-2 virus receptor. Experimental results show that our proposed model works effectively for both virus-human and bacteria-human protein–protein interaction prediction tasks. We share our code for reproducibility and future research at https://git.l3s.uni-hannover.de/dong/multitask-transfer.
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| 12. |
- Fedeli, Chiara, et al.
(författare)
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Axl can serve as entry factor for lassa virus depending on the functional glycosylation of dystroglycan
- 2018
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Ingår i: Journal of Virology. - 0022-538X .- 1098-5514. ; 92:5
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Tidskriftsartikel (refereegranskat)abstract
- The highly pathogenic arenavirus Lassa virus (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 posttranslational modification, which does not always correlate with tissue tropism. The broadly expressed phosphatidylserine receptor Axl was recently identified as an alternative LASV receptor candidate, but its role in LASV entry is unclear. Here, we investigate the exact role of Axl in LASV entry as a function of DG's posttranslational modification. We found that in the 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 for targeting Axl in antiviral therapy.
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| 13. |
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| 14. |
- Gerold, Gisa, 1979-, et al.
(författare)
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A Toll-like receptor 2-integrin beta3 complex senses bacterial lipopeptides via vitronectin.
- 2008
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Ingår i: Nature Immunology. - : Springer Science and Business Media LLC. - 1529-2908 .- 1529-2916. ; 9:7, s. 761-8
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Tidskriftsartikel (refereegranskat)abstract
- Toll-like receptor 2 (TLR2) initiates inflammation in response to bacterial lipopeptide (BLP). However, the molecular mechanisms enabling the detection of BLP by TLR2 are unknown. Here we investigated the interaction of BLP with human serum proteins and identified vitronectin as a BLP-recognition molecule. Vitronectin and its receptor, integrin beta(3), were required for BLP-induced TLR2-mediated activation of human monocytes. Furthermore, monocytes from patients with Glanzmann thrombasthenia, which lack integrin beta(3), were completely unresponsive to BLP. In addition, integrin beta(3) formed a complex with TLR2 and this complex dissociated after BLP stimulation. Notably, vitronectin and integrin beta(3) coordinated responses to other TLR2 agonists such as lipoteichoic acid and zymosan. Our findings show that vitronectin and integrin beta(3) contribute to the initiation of TLR2 responses.
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| 15. |
- Gerold, Gisa, 1979-, et al.
(författare)
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Decoding protein networks during virus entry by quantitative proteomics
- 2016
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Ingår i: Virus Research. - : Elsevier. - 0168-1702 .- 1872-7492. ; 218, s. 25-39
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Tidskriftsartikel (refereegranskat)abstract
- Virus entry into host cells relies on interactions between viral and host structures including lipids, carbohydrates and proteins. Particularly, protein-protein interactions between viral surface proteins and host proteins as well as secondary host protein-protein interactions play a pivotal role in coordinating virus binding and uptake. These interactions are dynamic and frequently involve multiprotein complexes. In the past decade mass spectrometry based proteomics methods have reached sensitivities and high throughput compatibilities of genomics methods and now allow the reliable quantitation of proteins in complex samples from limited material. As proteomics provides essential information on the biologically active entity namely the protein, including its posttranslational modifications and its interactions with other proteins, it is an indispensable method in the virologist's toolbox. Here we review protein interactions during virus entry and compare classical biochemical methods to study entry with novel technically advanced quantitative proteomics techniques. We highlight the value of quantitative proteomics in mapping functional virus entry networks, discuss the benefits and limitations and illustrate how the methodology will help resolve unsettled questions in virus entry research in the future.
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| 16. |
- Gerold, Gisa, 1979-, et al.
(författare)
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Hepatitis C Virus Entry : Protein Interactions and Fusion Determinants Governing Productive Hepatocyte Invasion
- 2020
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Ingår i: Cold Spring Harbor Perspectives in Medicine. - : Cold Spring Harbor Laboratory Press (CSHL). - 2157-1422. ; 10:2
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Tidskriftsartikel (refereegranskat)abstract
- Hepatitis C virus (HCV) entry is among the best-studied uptake processes for human pathogenic viruses. Uptake follows a spatially and temporally tightly controlled program. Numerous host factors including proteins, lipids, and glycans promote productive uptake of HCV particles into human liver cells. The virus initially attaches to surface proteoglycans, lipid receptors such as the scavenger receptor BI (SR-BI), and to the tetraspanin CD81. After lateral translocation of virions to tight junctions, claudin-1 (CLDN1) and occludin (OCLN) are essential for entry. Clathrin-mediated endocytosis engulfs HCV particles, which fuse with endosoma I membranes after pH drop. Uncoating of the viral RNA genome in the cytoplasm completes the entry process. Here we systematically review and classify HCV entry factors by their mechanistic role, relevance, and level of evidence. Finally, we report on more recent knowledge on determinants of membrane fusion and close with an outlook on future implications of HCV entry research.
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| 17. |
- Gerold, Gisa, 1979-, et al.
(författare)
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Hepatitis C virus NS5B polymerase primes innate immune signaling
- 2013
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Ingår i: Hepatology. - Hoboken : Wiley-Blackwell. - 0270-9139 .- 1527-3350. ; 57:3, s. 1275-1277
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Tidskriftsartikel (refereegranskat)abstract
- Innate immunity controls pathogen replication and spread. Yet, certain pathogens, such as Hepatitis C Virus (HCV), escape immune elimination and establish persistent infections that promote chronic inflammation and related diseases. Whereas HCV regulatory proteins that attenuate antiviral responses are known, those that promote inflammation and liver injury remain to be identified. Here, we show that transient expression of HCV RNA-dependent RNA polymerase (RdRp), NS5B, in mouse liver and human hepatocytes results in production of small RNA species that activate innate immune signaling via TBK1-IRF3 and NF-kappa B and induce cytokine production, including type I interferons (IFN) and IL-6. NS5B-expression also results in liver damage.
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| 18. |
- Gerold, Gisa, 1979-, et al.
(författare)
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Locking out hepatitis C
- 2011
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Ingår i: Nature Medicine. - : Springer Science and Business Media LLC. - 1078-8956 .- 1546-170X. ; 17:5, s. 542-4
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Tidskriftsartikel (refereegranskat)
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| 19. |
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| 20. |
- Gerold, Gisa, 1979-, et al.
(författare)
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Quantitative Proteomics Identifies Serum Response Factor Binding Protein 1 as a Host Factor for Hepatitis C Virus Entry
- 2015
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Ingår i: Cell Reports. - : Elsevier BV. - 2211-1247. ; 12:5, s. 864-878
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Tidskriftsartikel (refereegranskat)abstract
- Hepatitis C virus (HCV) enters human hepatocytes through a multistep mechanism involving, among other host proteins, the virus receptor CD81. How CD81 governs HCV entry is poorly characterized, and CD81 protein interactions after virus binding remain elusive. We have developed a quantitative proteomics protocol to identify HCV-triggered CD81 interactions and found 26 dynamic binding partners. At least six of these proteins promote HCV infection, as indicated by RNAi. We further characterized serum response factor binding protein 1 (SRFBP1), which is recruited to CD81 during HCV uptake and supports HCV infection in hepatoma cells and primary human hepatocytes. SRFBP1 facilitates host cell penetration by all seven HCV genotypes, but not of vesicular stomatitis virus and human coronavirus. Thus, SRFBP1 is an HCV-specific, pan-genotypic host entry factor. These results demonstrate the use of quantitative proteomics to elucidate pathogen entry and underscore the importance of host protein-protein interactions during HCV invasion.
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| 21. |
- Gerold, Gisa, 1979-, et al.
(författare)
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Teaching new tricks to an old foe : murinizing hepatitis C virus
- 2010
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Ingår i: Hepatology. - : American Association for the Study of Liver Diseases. - 0270-9139 .- 1527-3350. ; 52:6, s. 2233-2236
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Tidskriftsartikel (refereegranskat)abstract
- 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.
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| 22. |
- Gerold, Gisa, 1979-, et al.
(författare)
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The HCV life cycle : in vitro tissue culture systems and therapeutic targets
- 2014
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Ingår i: Digestive Diseases. - : S. Karger. - 0257-2753 .- 1421-9875. ; 32:5, s. 525-537
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Tidskriftsartikel (refereegranskat)abstract
- Hepatitis C virus (HCV) is a highly variable plus-strand RNA virus of the family Flaviviridae. Viral strains are grouped into six epidemiologically relevant genotypes that differ from each other by more than 30% at the nucleotide level. The variability of HCV allows immune evasion and facilitates persistence. It is also a substantial challenge for the development of specific antiviral therapies effective across all HCV genotypes and for prevention of drug resistance. Novel HCV cell culture models were instrumental for identification and profiling of therapeutic strategies. Concurrently, these models revealed numerous host factors critical for HCV propagation, some of which have emerged as targets for antiviral therapy. It is generally assumed that the use of host factors is conserved among HCV isolates and genotypes. Additionally, the barrier to viral resistance is thought to be high when interfering with host factors. Therefore, current drug development includes both targeting of viral factors but also of host factors essential for virus replication. In fact, some of these host-targeting agents, for instance inhibitors of cyclophilin A, have advanced to late stage clinical trials. Here, we highlight currently available cell culture systems for HCV, review the most prominent host-targeting strategies against hepatitis C and critically discuss opportunities and risks associated with host-targeting antiviral strategies.
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| 23. |
- Gerold, Gisa, 1979-, et al.
(författare)
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What is the role of Toll-like receptors in bacterial infections?
- 2007
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Ingår i: Seminars in Immunology. - : Elsevier BV. - 1044-5323 .- 1096-3618. ; 19:1, s. 41-7
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Tidskriftsartikel (refereegranskat)abstract
- Innate immunity relies on signalling by Toll-like receptors (TLRs) to alert the immune system of the presence of invading bacteria. TLR activation leads to the release of cytokines that allow for effective innate and adaptive immune responses. However, the contribution of different TLRs depends on the site of the infection and the pathogen. This review will describe the involvement of TLRs in the development of three different bacterial infections as well as our current understanding of the role of TLRs during microbial pathogenesis.
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| 24. |
- Haid, Sibylle, et al.
(författare)
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Repurposing screen identifies novel candidates for broad-spectrum coronavirus antivirals and druggable host targets
- 2024
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Ingår i: Antimicrobial Agents and Chemotherapy. - : American Society for Microbiology. - 0066-4804 .- 1098-6596. ; 68:3
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Tidskriftsartikel (refereegranskat)abstract
- Libraries composed of licensed drugs represent a vast repertoire of molecules modulating physiological processes in humans, providing unique opportunities for the discovery of host-targeting antivirals. We screened the Repurposing, Focused Rescue, and Accelerated Medchem (ReFRAME) repurposing library with approximately 12,000 molecules for broad-spectrum coronavirus antivirals and discovered 134 compounds inhibiting an alphacoronavirus and mapping to 58 molecular target categories. Dominant targets included the 5-hydroxytryptamine receptor, the dopamine receptor, and cyclin-dependent kinases. Gene knock-out of the drugs’ host targets including cathepsin B and L (CTSB/L; VBY-825), the aryl hydrocarbon receptor (AHR; Phortress), the farnesyl-diphosphate farnesyltransferase 1 (FDFT1; P-3622), and the kelch-like ECH-associated protein 1 (KEAP1; Omaveloxolone), significantly modulated HCoV-229E infection, providing evidence that these compounds inhibited the virus through acting on their respective host targets. Counter-screening of all 134 primary compound candidates with SARS-CoV-2 and validation in primary cells identified Phortress, an AHR activating ligand, P-3622-targeting FDFT1, and Omaveloxolone, which activates the NFE2-like bZIP transcription factor 2 (NFE2L2) by liberating it from its endogenous inhibitor KEAP1, as antiviral candidates for both an Alpha- and a Betacoronavirus. This study provides an overview of HCoV-229E repurposing candidates and reveals novel potentially druggable viral host dependency factors hijacked by diverse coronaviruses.
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| 25. |
- Herrador, Antonio, et al.
(författare)
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Dynamic Dystroglycan Complexes Mediate Cell Entry of Lassa Virus
- 2019
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Ingår i: mBio. - : American Society for Microbiology. - 2161-2129 .- 2150-7511. ; 10:2
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Tidskriftsartikel (refereegranskat)abstract
- Recognition of functional receptors by viruses is a key determinant for their host range, tissue tropism, and disease potential. The highly pathogenic Lassa virus (LASV) currently represents one of the most important emerging pathogens. The major cellular receptor for LASV in human cells is the ubiquitously expressed and evolutionary highly conserved extracellular matrix receptor dystroglycan (DG). In the host, DG interacts with many cellular proteins in a tissue-specific manner. The resulting distinct supramolecular complexes likely represent the functional units for viral entry, and preexisting protein-protein interactions may critically influence DG's function in productive viral entry. Using an unbiased shotgun proteomic approach, we define the largely unknown molecular composition of DG complexes present in highly susceptible epithelial cells that represent important targets for LASV during viral transmission. We further show that the specific composition of cellular DG complexes can affect DG's function in receptor-mediated endocytosis of the virus. Under steady-state conditions, epithelial DG complexes underwent rapid turnover via an endocytic pathway that shared some characteristics with DG-mediated LASV entry. However, compared to steady-state uptake of DG, LASV entry via DG occurred faster and critically depended on additional signaling by receptor tyrosine kinases and the downstream effector p21-activating kinase. In sum, we show that the specific molecular composition of DG complexes in susceptible cells is a determinant for productive virus entry and that the pathogen can manipulate the existing DG-linked endocytic pathway. This highlights another level of complexity of virus-receptor interaction and provides possible cellular targets for therapeutic antiviral intervention.Importance: Recognition of cellular receptors allows emerging viruses to break species barriers and is an important determinant for their disease potential. Many virus receptors have complex tissue-specific interactomes, and preexisting protein-protein interactions may influence their function. Combining shotgun proteomics with a biochemical approach, we characterize the molecular composition of the functional receptor complexes used by the highly pathogenic Lassa virus (LASV) to invade susceptible human cells. We show that the specific composition of the receptor complexes affects productive entry of the virus, providing proof-of-concept. In uninfected cells, these functional receptor complexes undergo dynamic turnover involving an endocytic pathway that shares some characteristics with viral entry. However, steady-state receptor uptake and virus endocytosis critically differ in kinetics and underlying signaling, indicating that the pathogen can manipulate the receptor complex according to its needs. Our study highlights a remarkable complexity of LASV-receptor interaction and identifies possible targets for therapeutic antiviral intervention.
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