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Tillmanns J, Kicuntod J, Lösing J, Marschall M. 'Getting Better'-Is It a Feasible Strategy of Broad Pan-Antiherpesviral Drug Targeting by Using the Nuclear Egress-Directed Mechanism? Int J Mol Sci 2024; 25:2823. [PMID: 38474070 DOI: 10.3390/ijms25052823] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2024] [Revised: 02/24/2024] [Accepted: 02/26/2024] [Indexed: 03/14/2024] Open
Abstract
The herpesviral nuclear egress represents an essential step of viral replication efficiency in host cells, as it defines the nucleocytoplasmic release of viral capsids. Due to the size limitation of the nuclear pores, viral nuclear capsids are unable to traverse the nuclear envelope without a destabilization of this natural host-specific barrier. To this end, herpesviruses evolved the regulatory nuclear egress complex (NEC), composed of a heterodimer unit of two conserved viral NEC proteins (core NEC) and a large-size extension of this complex including various viral and cellular NEC-associated proteins (multicomponent NEC). Notably, the NEC harbors the pronounced ability to oligomerize (core NEC hexamers and lattices), to multimerize into higher-order complexes, and, ultimately, to closely interact with the migrating nuclear capsids. Moreover, most, if not all, of these NEC proteins comprise regulatory modifications by phosphorylation, so that the responsible kinases, and additional enzymatic activities, are part of the multicomponent NEC. This sophisticated basis of NEC-specific structural and functional interactions offers a variety of different modes of antiviral interference by pharmacological or nonconventional inhibitors. Since the multifaceted combination of NEC activities represents a highly conserved key regulatory stage of herpesviral replication, it may provide a unique opportunity towards a broad, pan-antiherpesviral mechanism of drug targeting. This review presents an update on chances, challenges, and current achievements in the development of NEC-directed antiherpesviral strategies.
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Affiliation(s)
- Julia Tillmanns
- Institute for Clinical and Molecular Virology, Friedrich-Alexander University of Erlangen-Nürnberg (FAU), 91054 Erlangen, Germany
| | - Jintawee Kicuntod
- Institute for Clinical and Molecular Virology, Friedrich-Alexander University of Erlangen-Nürnberg (FAU), 91054 Erlangen, Germany
| | - Josephine Lösing
- Institute for Clinical and Molecular Virology, Friedrich-Alexander University of Erlangen-Nürnberg (FAU), 91054 Erlangen, Germany
| | - Manfred Marschall
- Institute for Clinical and Molecular Virology, Friedrich-Alexander University of Erlangen-Nürnberg (FAU), 91054 Erlangen, Germany
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2
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Yu D, Wagner S, Schütz M, Jeon Y, Seo M, Kim J, Brückner N, Kicuntod J, Tillmanns J, Wangen C, Hahn F, Kaufer BB, Neipel F, Eickhoff J, Klebl B, Nam K, Marschall M. An Antiherpesviral Host-Directed Strategy Based on CDK7 Covalently Binding Drugs: Target-Selective, Picomolar-Dose, Cross-Virus Reactivity. Pharmaceutics 2024; 16:158. [PMID: 38399219 PMCID: PMC10892818 DOI: 10.3390/pharmaceutics16020158] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2023] [Revised: 01/12/2024] [Accepted: 01/18/2024] [Indexed: 02/25/2024] Open
Abstract
The repertoire of currently available antiviral drugs spans therapeutic applications against a number of important human pathogens distributed worldwide. These include cases of the pandemic severe acute respiratory coronavirus type 2 (SARS-CoV-2 or COVID-19), human immunodeficiency virus type 1 (HIV-1 or AIDS), and the pregnancy- and posttransplant-relevant human cytomegalovirus (HCMV). In almost all cases, approved therapies are based on direct-acting antivirals (DAAs), but their benefit, particularly in long-term applications, is often limited by the induction of viral drug resistance or side effects. These issues might be addressed by the additional use of host-directed antivirals (HDAs). As a strong input from long-term experiences with cancer therapies, host protein kinases may serve as HDA targets of mechanistically new antiviral drugs. The study demonstrates such a novel antiviral strategy by targeting the major virus-supportive host kinase CDK7. Importantly, this strategy focuses on highly selective, 3D structure-derived CDK7 inhibitors carrying a warhead moiety that mediates covalent target binding. In summary, the main experimental findings of this study are as follows: (1) the in vitro verification of CDK7 inhibition and selectivity that confirms the warhead covalent-binding principle (by CDK-specific kinase assays), (2) the highly pronounced antiviral efficacies of the hit compounds (in cultured cell-based infection models) with half-maximal effective concentrations that reach down to picomolar levels, (3) a particularly strong potency of compounds against strains and reporter-expressing recombinants of HCMV (using infection assays in primary human fibroblasts), (4) additional activity against further herpesviruses such as animal CMVs and VZV, (5) unique mechanistic properties that include an immediate block of HCMV replication directed early (determined by Western blot detection of viral marker proteins), (6) a substantial drug synergism in combination with MBV (measured by a Loewe additivity fixed-dose assay), and (7) a strong sensitivity of clinically relevant HCMV mutants carrying MBV or ganciclovir resistance markers. Combined, the data highlight the huge developmental potential of this host-directed antiviral targeting concept utilizing covalently binding CDK7 inhibitors.
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Affiliation(s)
- DongHoon Yu
- Qurient Co., Ltd., C-Dong, 242 Pangyo-ro, C801 Bundang-gu, Seongnam-si 13487, Republic of Korea
| | - Sabrina Wagner
- Institute for Clinical and Molecular Virolosgy, Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU), Schlossgarten 4, 91054 Erlangen, Germany
| | - Martin Schütz
- Institute for Clinical and Molecular Virolosgy, Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU), Schlossgarten 4, 91054 Erlangen, Germany
| | - Yeejin Jeon
- Qurient Co., Ltd., C-Dong, 242 Pangyo-ro, C801 Bundang-gu, Seongnam-si 13487, Republic of Korea
| | - Mooyoung Seo
- Qurient Co., Ltd., C-Dong, 242 Pangyo-ro, C801 Bundang-gu, Seongnam-si 13487, Republic of Korea
| | - Jaeseung Kim
- Qurient Co., Ltd., C-Dong, 242 Pangyo-ro, C801 Bundang-gu, Seongnam-si 13487, Republic of Korea
| | - Nadine Brückner
- Institute for Clinical and Molecular Virolosgy, Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU), Schlossgarten 4, 91054 Erlangen, Germany
| | - Jintawee Kicuntod
- Institute for Clinical and Molecular Virolosgy, Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU), Schlossgarten 4, 91054 Erlangen, Germany
| | - Julia Tillmanns
- Institute for Clinical and Molecular Virolosgy, Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU), Schlossgarten 4, 91054 Erlangen, Germany
| | - Christina Wangen
- Institute for Clinical and Molecular Virolosgy, Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU), Schlossgarten 4, 91054 Erlangen, Germany
| | - Friedrich Hahn
- Institute for Clinical and Molecular Virolosgy, Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU), Schlossgarten 4, 91054 Erlangen, Germany
| | - Benedikt B. Kaufer
- Institute of Virology, Freie Universität Berlin, Robert-von-Ostertag-Straße 7–13, 14163 Berlin, Germany
| | - Frank Neipel
- Institute for Clinical and Molecular Virolosgy, Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU), Schlossgarten 4, 91054 Erlangen, Germany
| | - Jan Eickhoff
- Lead Discovery Center GmbH, Otto-Hahn-Straße 15, 44227 Dortmund, Germany
| | - Bert Klebl
- Lead Discovery Center GmbH, Otto-Hahn-Straße 15, 44227 Dortmund, Germany
- The Norwegian College of Fishery Science UiT, Arctic University of Norway, 9037 Tromsø, Norway
| | - Kiyean Nam
- Qurient Co., Ltd., C-Dong, 242 Pangyo-ro, C801 Bundang-gu, Seongnam-si 13487, Republic of Korea
| | - Manfred Marschall
- Institute for Clinical and Molecular Virolosgy, Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU), Schlossgarten 4, 91054 Erlangen, Germany
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Wangen C, Raithel A, Tillmanns J, Gege C, Herrmann A, Vitt D, Kohlhof H, Marschall M, Hahn F. Validation of nuclear receptor RORγ isoform 1 as a novel host-directed antiviral target based on the modulation of cholesterol levels. Antiviral Res 2024; 221:105769. [PMID: 38056603 DOI: 10.1016/j.antiviral.2023.105769] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2023] [Revised: 11/29/2023] [Accepted: 11/30/2023] [Indexed: 12/08/2023]
Abstract
Currently, the clinically approved repertoire of antiviral drugs predominantly comprises direct-acting antivirals (DAAs). However, the use of DAAs is frequently limited by adverse effects, restriction to individual virus species, or the induction of viral drug resistance. These issues will likely be resolved by the introduction of host-directed antivirals (HDAs) targeting cellular proteins crucial for viral replication. However, experiences with the development of antiviral HDAs and clinical applications are still in their infancy. With the present study, we explored the human nuclear receptor and transcription factor RORγ isoform 1 (RORγ1), a member of the retinoic acid receptor-related orphan receptor (ROR) family, as a putative target of antiviral HDAs. To this end, cell culture models were used to investigate major viral human pathogens, i.e. the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), human cytomegalovirus (HCMV), varicella zoster virus (VZV) and human immunodeficiency virus 1 (HIV-1). Our results demonstrated (i) an antiviral activity of the clinically relevant RORγ modulators cedirogant and others, (ii) that isoform RORγ1 acts as the responsible determinant and drug target in the analyzed cell culture-based models, (iii) a selectivity of the antiviral effect for RORγ1 over related receptors RORα and RORβ, (iv) a late-phase inhibition exerted by cedirogant in HCMV replication and (v) a mechanistic link to the cellular cholesterol biosynthesis. Combined, the data highlight this novel RORγ-specific antiviral targeting concept and the developmental potential of RORγ-directed small molecules.
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Affiliation(s)
- Christina Wangen
- Institute for Clinical and Molecular Virology, Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU), Erlangen, Germany.
| | - Andrea Raithel
- Institute for Clinical and Molecular Virology, Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU), Erlangen, Germany.
| | - Julia Tillmanns
- Institute for Clinical and Molecular Virology, Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU), Erlangen, Germany.
| | | | - Alexandra Herrmann
- Institute for Clinical and Molecular Virology, Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU), Erlangen, Germany; Immunic AG, Gräfelfing, Germany.
| | | | | | - Manfred Marschall
- Institute for Clinical and Molecular Virology, Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU), Erlangen, Germany.
| | - Friedrich Hahn
- Institute for Clinical and Molecular Virology, Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU), Erlangen, Germany.
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Schütz M, Cordsmeier A, Wangen C, Horn AHC, Wyler E, Ensser A, Sticht H, Marschall M. The Interactive Complex between Cytomegalovirus Kinase vCDK/pUL97 and Host Factors CDK7-Cyclin H Determines Individual Patterns of Transcription in Infected Cells. Int J Mol Sci 2023; 24:17421. [PMID: 38139252 PMCID: PMC10744309 DOI: 10.3390/ijms242417421] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2023] [Revised: 12/06/2023] [Accepted: 12/09/2023] [Indexed: 12/24/2023] Open
Abstract
The infection of human cytomegalovirus (HCMV) is strongly determined by the host-cell interaction in a way that the efficiency of HCMV lytic replication is dependent on the regulatory interplay between viral and cellular proteins. In particular, the activities of protein kinases, such as cyclin-dependent kinases (CDKs) and the viral CDK ortholog (vCDK/pUL97), play an important role in both viral reproduction and virus-host interaction. Very recently, we reported on the complexes formed between vCDK/pUL97, human cyclin H, and CDK7. Major hallmarks of this interplay are the interaction between cyclin H and vCDK/pUL97, which is consistently detectable across various conditions and host cell types of infection, the decrease or increase in pUL97 kinase activity resulting from cyclin H knock-down or elevated levels, respectively, and significant trans-stimulation of human CDK7 activity by pUL97 in vitro. Due to the fact that even a ternary complex of vCDK/pUL97-cyclin H-CDK7 can be detected by coimmunoprecipitation and visualized by bioinformatic structural modeling, we postulated a putative impact of the respective kinase activities on the patterns of transcription in HCMV-infected cells. Here, we undertook a first vCDK/pUL97-specific transcriptomic analysis, which combined conditions of fully lytic HCMV replication with those under specific vCDK/pUL97 or CDK7 drug-mediated inhibition or transient cyclin H knockout. The novel results were further strengthened using bioinformatic modeling of the involved multi-protein complexes. Our data underline the importance of these kinase activities for the C-terminal domain (CTD) phosphorylation-driven activation of host RNA polymerase in HCMV-infected cells. The impact of the individual experimental conditions on differentially expressed gene profiles is described in detail and discussed.
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Affiliation(s)
- Martin Schütz
- Institute for Clinical and Molecular Virology, Friedrich-Alexander University of Erlangen-Nürnberg (FAU), 91054 Erlangen, Germany
| | - Arne Cordsmeier
- Institute for Clinical and Molecular Virology, Friedrich-Alexander University of Erlangen-Nürnberg (FAU), 91054 Erlangen, Germany
| | - Christina Wangen
- Institute for Clinical and Molecular Virology, Friedrich-Alexander University of Erlangen-Nürnberg (FAU), 91054 Erlangen, Germany
| | - Anselm H. C. Horn
- Division of Bioinformatics, Institute of Biochemistry, Friedrich-Alexander University of Erlangen-Nürnberg (FAU), 91054 Erlangen, Germany
| | - Emanuel Wyler
- Max-Delbrück-Center for Molecular Medicine (MDC), 13125 Berlin, Germany
| | - Armin Ensser
- Institute for Clinical and Molecular Virology, Friedrich-Alexander University of Erlangen-Nürnberg (FAU), 91054 Erlangen, Germany
| | - Heinrich Sticht
- Division of Bioinformatics, Institute of Biochemistry, Friedrich-Alexander University of Erlangen-Nürnberg (FAU), 91054 Erlangen, Germany
| | - Manfred Marschall
- Institute for Clinical and Molecular Virology, Friedrich-Alexander University of Erlangen-Nürnberg (FAU), 91054 Erlangen, Germany
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Wild M, Karner D, Eickhoff J, Wagner S, Kicuntod J, Chang W, Barry P, Jonjić S, Lenac Roviš T, Marschall M. Combined Treatment with Host-Directed and Anticytomegaloviral Kinase Inhibitors: Mechanisms, Synergisms and Drug Resistance Barriers. Pharmaceutics 2023; 15:2680. [PMID: 38140021 PMCID: PMC10748244 DOI: 10.3390/pharmaceutics15122680] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2023] [Revised: 11/20/2023] [Accepted: 11/23/2023] [Indexed: 12/24/2023] Open
Abstract
Despite the availability of currently approved antiviral drugs, infections with human cytomegalovirus (HCMV) still cause clinically challenging, sometimes life-threatening situations. There is an urgent need for enhanced anti-HCMV drugs that offer improved efficacy, reduced dosages and options for long-term treatment without risk of the development of viral drug resistance. Recently, we reported the pronounced anti-HCMV efficacy of pharmacological inhibitors of cyclin-dependent kinases (CDKs), in particular, the potential of utilizing drug synergies upon combination treatment with inhibitors of host CDKs and the viral CDK-like kinase pUL97 (vCDK/pUL97). Here, we expand this finding by further assessing the in vitro synergistic antiviral interaction between vCDK and CDK inhibitors towards HCMV as well as non-human cytomegaloviruses. An extension of this synergy approach was achieved in vivo by using the recombinant MCMV-UL97/mouse model, confirming the high potential of combination treatment with the clinically approved vCDK inhibitor maribavir (MBV) and the developmental CDK7 inhibitor LDC4297. Moreover, mechanistic aspects of this synergistic drug combination were illustrated on the levels of intracellular viral protein transport and viral genome replication. The analysis of viral drug resistance did not reveal resistance formation in the case of MBV + LDC4297 combination treatment. Spanning various investigational levels, these new results strongly support our concept, employing the great potential of anti-HCMV synergistic drug treatment.
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Affiliation(s)
- Markus Wild
- Institute for Clinical and Molecular Virology, Friedrich-Alexander University of Erlangen-Nürnberg (FAU), Schlossgarten 4, 91054 Erlangen, Germany; (M.W.); (S.W.); (J.K.)
| | - Dubravka Karner
- Center for Proteomics, Faculty of Medicine, University of Rijeka, Brace Branchetta 20, 51000 Rijeka, Croatia; (D.K.); (S.J.); (T.L.R.)
| | - Jan Eickhoff
- Lead Discovery Center GmbH, Otto-Hahn-Str. 15, 44227 Dortmund, Germany;
| | - Sabrina Wagner
- Institute for Clinical and Molecular Virology, Friedrich-Alexander University of Erlangen-Nürnberg (FAU), Schlossgarten 4, 91054 Erlangen, Germany; (M.W.); (S.W.); (J.K.)
| | - Jintawee Kicuntod
- Institute for Clinical and Molecular Virology, Friedrich-Alexander University of Erlangen-Nürnberg (FAU), Schlossgarten 4, 91054 Erlangen, Germany; (M.W.); (S.W.); (J.K.)
| | - William Chang
- Department of Medical Microbiology and Immunology, California National Primate Research Center, University of California, 3146 Tupper Hall, 1 Shields Avenue, Davis, CA 95616, USA; (W.C.); (P.B.)
| | - Peter Barry
- Department of Medical Microbiology and Immunology, California National Primate Research Center, University of California, 3146 Tupper Hall, 1 Shields Avenue, Davis, CA 95616, USA; (W.C.); (P.B.)
| | - Stipan Jonjić
- Center for Proteomics, Faculty of Medicine, University of Rijeka, Brace Branchetta 20, 51000 Rijeka, Croatia; (D.K.); (S.J.); (T.L.R.)
| | - Tihana Lenac Roviš
- Center for Proteomics, Faculty of Medicine, University of Rijeka, Brace Branchetta 20, 51000 Rijeka, Croatia; (D.K.); (S.J.); (T.L.R.)
| | - Manfred Marschall
- Institute for Clinical and Molecular Virology, Friedrich-Alexander University of Erlangen-Nürnberg (FAU), Schlossgarten 4, 91054 Erlangen, Germany; (M.W.); (S.W.); (J.K.)
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Hoffmann H, Ebensperger M, Schönsiegel A, Hamza H, Koch-Heier J, Schreiber A, Ludwig S, Schindler M, Planz O. Influenza A virus replication has a stronger dependency on Raf/MEK/ERK signaling pathway activity than SARS-CoV-2. Front Cell Infect Microbiol 2023; 13:1264983. [PMID: 37965261 PMCID: PMC10641236 DOI: 10.3389/fcimb.2023.1264983] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2023] [Accepted: 10/10/2023] [Indexed: 11/16/2023] Open
Abstract
The recent COVID-19 pandemic again highlighted the urgent need for broad-spectrum antivirals, both for therapeutic use in acute viral infection and for pandemic preparedness in general. The targeting of host cell factors hijacked by viruses during their replication cycle presents one possible strategy for development of broad-spectrum antivirals. By inhibiting the Raf/MEK/ERK signaling pathway, a central kinase cascade of eukaryotic cells, which is being exploited by numerous viruses of different virus phyla, the small-molecule MEK inhibitor zapnometinib has the potential to address this need. We here performed a side-by-side comparison of the antiviral efficacy of zapnometinib against IAV and SARS-CoV-2 to determine the concentration leading to 50% of its effect on the virus (EC50) and the concentration leading to 50% reduction of ERK phosphorylation (IC50) in a comparable manner, using the same experimental conditions. Our results show that the EC50 value and IC50 value of zapnometinib are indeed lower for IAV compared to SARS-CoV-2 using one representative strain for each. The results suggest that IAV's replication has a stronger dependency on an active Raf/MEK/ERK pathway and, thus, that IAV is more susceptible to treatment with zapnometinib than SARS-CoV-2. With zapnometinib's favorable outcome in a recent phase II clinical trial in hospitalized COVID-19 patients, the present results are even more promising for an upcoming phase II clinical trial in severe influenza virus infection.
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Affiliation(s)
- Helen Hoffmann
- Department of Immunology, Interfaculty Institute for Cell Biology, Eberhard Karls Universitaet Tuebingen, Tuebingen, Germany
- Atriva Therapeutics GmbH, Tuebingen, Germany
| | | | - Annika Schönsiegel
- Department of Immunology, Interfaculty Institute for Cell Biology, Eberhard Karls Universitaet Tuebingen, Tuebingen, Germany
- Atriva Therapeutics GmbH, Tuebingen, Germany
| | - Hazem Hamza
- Department of Immunology, Interfaculty Institute for Cell Biology, Eberhard Karls Universitaet Tuebingen, Tuebingen, Germany
- Virology Laboratory, Environmental Research Division, National Research Centre, Giza, Egypt
| | - Julia Koch-Heier
- Department of Immunology, Interfaculty Institute for Cell Biology, Eberhard Karls Universitaet Tuebingen, Tuebingen, Germany
- Atriva Therapeutics GmbH, Tuebingen, Germany
| | - André Schreiber
- Institute of Virology (IVM), Westfaelische Wilhelms Universitaet, Muenster, Muenster, Germany
| | - Stephan Ludwig
- Institute of Virology (IVM), Westfaelische Wilhelms Universitaet, Muenster, Muenster, Germany
| | - Michael Schindler
- Department of Molecular Virology, Institute for Medical Virology and Epidemiology of Viral Disease, University Hospital Tuebingen, Tuebingen, Germany
| | - Oliver Planz
- Department of Immunology, Interfaculty Institute for Cell Biology, Eberhard Karls Universitaet Tuebingen, Tuebingen, Germany
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Schütz M, Wangen C, Sommerer M, Kögler M, Eickhoff J, Degenhart C, Klebl B, Naing Z, Egilmezer E, Hamilton ST, Rawlinson WD, Sticht H, Marschall M. Cytomegalovirus cyclin-dependent kinase ortholog vCDK/pUL97 undergoes regulatory interaction with human cyclin H and CDK7 to codetermine viral replication efficiency. Virus Res 2023; 335:199200. [PMID: 37591314 PMCID: PMC10445456 DOI: 10.1016/j.virusres.2023.199200] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2023] [Revised: 08/11/2023] [Accepted: 08/14/2023] [Indexed: 08/19/2023]
Abstract
Human cytomegalovirus (HCMV) infection is shaped by a tightly regulated interplay between viral and cellular proteins. Distinct kinase activities, such as the viral cyclin-dependent kinase ortholog (vCDK) pUL97 and cellular CDK7 are both crucial for efficient viral replication. Previously, we reported that both kinases, vCDK/pUL97 and CDK7, interact with cyclin H, thereby achieving an enhanced level of kinase activity and overall functionality in viral replication. Here we provide a variety of novel results, as generated on a methodologically extended basis, and present a concept for the codetermination of viral replication efficiency through these kinase activities: (i) cyclin H expression, in various human cell types, is substantially upregulated by strains of HCMV including the clinically relevant HCMV Merlin; (ii) vCDK/pUL97 interacts with human cyclin H in both HCMV-infected and plasmid-transfected cell systems; (iii) a doxycycline-inducible shRNA-dependent knock-down (KD) of cyclin H significantly reduces pUL97 activity (qSox in vitro kinase assay); (iv) accordingly, pUL97 in vitro kinase activity is seen significantly increased upon addition of recombinant cyclin H; (v) as a point of specific importance, human CDK7 activity shows an increase by vCDK/pUL97-mediated trans-stimulation (whereas pUL97 is not stimulated by CDK7); (vi) phosphosite-specific antibodies indicate an upregulated CDK7 phosphorylation upon HCMV infection, as mediated through a pUL97-specific modulatory effect (i.e. shown by pUL97 inhibitor treatment or pUL97-deficient viral mutant); (vii) finally, an efficient KD of cyclin H in primary fibroblasts generally results in an impaired HCMV replication efficiency as measured on protein and genomic levels. These results show evidence for the codetermination of viral replication by vCDK/pUL97, cyclin H and CDK7, thus supporting the specific importance of cyclin H as a central regulatory factor, and suggesting novel targeting options for antiviral drugs.
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Affiliation(s)
- Martin Schütz
- Institute for Clinical and Molecular Virology, Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU), Schlossgarten 4, Erlangen 91054, Germany.
| | - Christina Wangen
- Institute for Clinical and Molecular Virology, Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU), Schlossgarten 4, Erlangen 91054, Germany
| | - Mona Sommerer
- Institute for Clinical and Molecular Virology, Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU), Schlossgarten 4, Erlangen 91054, Germany
| | - Melanie Kögler
- Institute for Clinical and Molecular Virology, Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU), Schlossgarten 4, Erlangen 91054, Germany
| | | | | | - Bert Klebl
- Lead Discovery Center GmbH, Dortmund, Germany
| | - Zin Naing
- Serology and Virology Division, NSW Health Pathology Microbiology, Prince of Wales Hospital, and Schools of Women's and Children's Health, Medicine and Biotechnology and Biomolecular Sciences, University of New South Wales, High Street, Sydney, Australia
| | - Ece Egilmezer
- Serology and Virology Division, NSW Health Pathology Microbiology, Prince of Wales Hospital, and Schools of Women's and Children's Health, Medicine and Biotechnology and Biomolecular Sciences, University of New South Wales, High Street, Sydney, Australia
| | - Stuart T Hamilton
- Serology and Virology Division, NSW Health Pathology Microbiology, Prince of Wales Hospital, and Schools of Women's and Children's Health, Medicine and Biotechnology and Biomolecular Sciences, University of New South Wales, High Street, Sydney, Australia
| | - William D Rawlinson
- Serology and Virology Division, NSW Health Pathology Microbiology, Prince of Wales Hospital, and Schools of Women's and Children's Health, Medicine and Biotechnology and Biomolecular Sciences, University of New South Wales, High Street, Sydney, Australia
| | - Heinrich Sticht
- Division of Bioinformatics, Institute of Biochemistry, FAU, Erlangen, Germany
| | - Manfred Marschall
- Institute for Clinical and Molecular Virology, Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU), Schlossgarten 4, Erlangen 91054, Germany.
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8
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Syrigos GV, Feige M, Dirlam A, Businger R, Gruska I, Wiebusch L, Hamprecht K, Schindler M. Abemaciclib restricts HCMV replication by suppressing pUL97-mediated phosphorylation of SAMHD1. Antiviral Res 2023; 217:105689. [PMID: 37516154 DOI: 10.1016/j.antiviral.2023.105689] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2023] [Accepted: 07/26/2023] [Indexed: 07/31/2023]
Abstract
Human cytomegalovirus (HCMV) is a herpesvirus that causes life-threatening infections in newborns or immunosuppressed patients. For viral replication, HCMV establishes a network of cellular interactions, among others cyclin-dependent kinases (CDK). Furthermore, HCMV encodes pUL97, a viral kinase, which is a CDK-homologue. HCMV uses pUL97 in order to phosphorylate and thereby antagonize SAMHD1, an antiviral host cell factor. Since HCMV has several mechanisms to evade restriction by SAMHD1, we first analyzed the kinetics of SAMHD1-inactivation and found that phosphorylation of SAMHD1 by pUL97 occurs directly after infection of macrophages. We hence hypothesized that inhibition of this process qualifies as efficient antiviral target and FDA approved CDK-inhibitors (CDKIs) might be potent antivirals that prevent the inactivation of SAMHD1. Indeed, Abemaciclib, a 2nd generation CDKI exhibited superior IC50s against HCMV in infected macrophages and the antiviral activity largely relied on its ability to block pUL97-mediated SAMHD1-phosphorylation. Altogether, our study highlights the therapeutic potential of clinically-approved CDKIs as antivirals against HCMV, sheds light on their mode of action and establishes SAMHD1 as a valid and highly potent therapeutic target.
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Affiliation(s)
- Georgios Vavouras Syrigos
- Institute for Medical Virology and Epidemiology of Viral Diseases, University Hospital Tübingen, Tübingen, Germany
| | - Maximilian Feige
- Institute for Medical Virology and Epidemiology of Viral Diseases, University Hospital Tübingen, Tübingen, Germany
| | - Alicia Dirlam
- Institute for Medical Virology and Epidemiology of Viral Diseases, University Hospital Tübingen, Tübingen, Germany
| | - Ramona Businger
- Institute for Medical Virology and Epidemiology of Viral Diseases, University Hospital Tübingen, Tübingen, Germany
| | - Iris Gruska
- Laboratory of Molecular Pediatrics, Department of Pediatric Oncology and Hematology, Charité - Universitätsmedizin Berlin, Berlin, Germany
| | - Lüder Wiebusch
- Laboratory of Molecular Pediatrics, Department of Pediatric Oncology and Hematology, Charité - Universitätsmedizin Berlin, Berlin, Germany
| | - Klaus Hamprecht
- Institute for Medical Virology and Epidemiology of Viral Diseases, University Hospital Tübingen, Tübingen, Germany
| | - Michael Schindler
- Institute for Medical Virology and Epidemiology of Viral Diseases, University Hospital Tübingen, Tübingen, Germany.
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Tillmanns J, Häge S, Borst EM, Wardin J, Eickhoff J, Klebl B, Wagner S, Wangen C, Hahn F, Socher E, Marschall M. Assessment of Covalently Binding Warhead Compounds in the Validation of the Cytomegalovirus Nuclear Egress Complex as an Antiviral Target. Cells 2023; 12:cells12081162. [PMID: 37190072 DOI: 10.3390/cells12081162] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2023] [Revised: 04/06/2023] [Accepted: 04/06/2023] [Indexed: 05/17/2023] Open
Abstract
Herpesviral nuclear egress is a regulated process of viral capsid nucleocytoplasmic release. Due to the large capsid size, a regular transport via the nuclear pores is unfeasible, so that a multistage-regulated export pathway through the nuclear lamina and both leaflets of the nuclear membrane has evolved. This process involves regulatory proteins, which support the local distortion of the nuclear envelope. For human cytomegalovirus (HCMV), the nuclear egress complex (NEC) is determined by the pUL50-pUL53 core that initiates multicomponent assembly with NEC-associated proteins and capsids. The transmembrane NEC protein pUL50 serves as a multi-interacting determinant that recruits regulatory proteins by direct and indirect contacts. The nucleoplasmic core NEC component pUL53 is strictly associated with pUL50 in a structurally defined hook-into-groove complex and is considered as the potential capsid-binding factor. Recently, we validated the concept of blocking the pUL50-pUL53 interaction by small molecules as well as cell-penetrating peptides or an overexpression of hook-like constructs, which can lead to a pronounced degree of antiviral activity. In this study, we extended this strategy by utilizing covalently binding warhead compounds, originally designed as binders of distinct cysteine residues in target proteins, such as regulatory kinases. Here, we addressed the possibility that warheads may likewise target viral NEC proteins, building on our previous crystallization-based structural analyses that revealed distinct cysteine residues in positions exposed from the hook-into-groove binding surface. To this end, the antiviral and NEC-binding properties of a selection of 21 warhead compounds were investigated. The combined findings are as follows: (i) warhead compounds exhibited a pronounced anti-HCMV potential in cell-culture-based infection models; (ii) computational analysis of NEC primary sequences and 3D structures revealed cysteine residues exposed to the hook-into-groove interaction surface; (iii) several of the active hit compounds exhibited NEC-blocking activity, as shown at the single-cell level by confocal imaging; (iv) the clinically approved warhead drug ibrutinib exerted a strong inhibitory impact on the pUL50-pUL53 core NEC interaction, as demonstrated by the NanoBiT assay system; and (v) the generation of recombinant HCMV ∆UL50-ΣUL53, allowing the assessment of viral replication under conditional expression of the viral core NEC proteins, was used for characterizing viral replication and a mechanistic evaluation of ibrutinib antiviral efficacy. Combined, the results point to a rate-limiting importance of the HCMV core NEC for viral replication and to the option of exploiting this determinant by the targeting of covalently NEC-binding warhead compounds.
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Affiliation(s)
- Julia Tillmanns
- Institute for Clinical and Molecular Virology, Friedrich-Alexander University of Erlangen-Nürnberg (FAU), 91054 Erlangen, Germany
| | - Sigrun Häge
- Institute for Clinical and Molecular Virology, Friedrich-Alexander University of Erlangen-Nürnberg (FAU), 91054 Erlangen, Germany
| | - Eva Maria Borst
- Institute of Virology, Hannover Medical School, 30625 Hannover, Germany
| | - Julia Wardin
- Institute for Clinical and Molecular Virology, Friedrich-Alexander University of Erlangen-Nürnberg (FAU), 91054 Erlangen, Germany
| | - Jan Eickhoff
- Lead Discovery Center GmbH (LDC), 44227 Dortmund, Germany
| | - Bert Klebl
- Lead Discovery Center GmbH (LDC), 44227 Dortmund, Germany
- The Norwegian College of Fishery Science UiT, The Arctic University of Norway, 9037 Tromsø, Norway
| | - Sabrina Wagner
- Institute for Clinical and Molecular Virology, Friedrich-Alexander University of Erlangen-Nürnberg (FAU), 91054 Erlangen, Germany
| | - Christina Wangen
- Institute for Clinical and Molecular Virology, Friedrich-Alexander University of Erlangen-Nürnberg (FAU), 91054 Erlangen, Germany
| | - Friedrich Hahn
- Institute for Clinical and Molecular Virology, Friedrich-Alexander University of Erlangen-Nürnberg (FAU), 91054 Erlangen, Germany
| | - Eileen Socher
- Institute of Anatomy, Functional and Clinical Anatomy, FAU, 91054 Erlangen, Germany
| | - Manfred Marschall
- Institute for Clinical and Molecular Virology, Friedrich-Alexander University of Erlangen-Nürnberg (FAU), 91054 Erlangen, Germany
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The Oligomeric Assemblies of Cytomegalovirus Core Nuclear Egress Proteins Are Associated with Host Kinases and Show Sensitivity to Antiviral Kinase Inhibitors. Viruses 2022; 14:v14051021. [PMID: 35632762 PMCID: PMC9146606 DOI: 10.3390/v14051021] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2022] [Revised: 05/03/2022] [Accepted: 05/09/2022] [Indexed: 02/04/2023] Open
Abstract
The nucleo-cytoplasmic capsid egress of herpesviruses is a unique regulated process that ensures the efficiency of viral replication and release. For human cytomegalovirus (HCMV), the core of the nuclear egress complex (NEC) consists of the pUL50–pUL53 heterodimer that is able to oligomerize and thus to build hexameric lattices. These structures determine capsid binding and multicomponent protein interaction including NEC-associated host factors. The underlying characteristic of the core NEC formation is based on the N-terminal hook structure of pUL53 that binds into an alpha-helical groove of pUL50, and is thus described as a hook-into-groove interaction. This central regulatory element has recently been validated as a target of antiviral strategies, and first NEC-targeted prototypes of inhibitory small molecules were reported by our previous study. Here, we further analyzed the oligomerization properties of the viral NEC through an approach of chemical protein cross-linking. Findings were as follows: (i) a cross-link approach demonstrated the oligomeric state of the HCMV core NEC using material from HCMV-infected or plasmid-transfected cells, (ii) a Western blot-based identification of NEC-associated kinases using the cross-linked multicomponent NECs was successful, and (iii) we demonstrated the NEC-inhibitory and antiviral activity of specific inhibitors directed to these target kinases. Combined, the results strongly underline the functional importance of the oligomerization of the HCMV-specific NEC that is both phosphorylation-dependent and sensitive to antiviral kinase inhibitors.
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