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Iwaisako Y, Fujimuro M. The Terminase Complex of Each Human Herpesvirus. Biol Pharm Bull 2024; 47:912-916. [PMID: 38692868 DOI: 10.1248/bpb.b23-00717] [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] [Indexed: 05/03/2024]
Abstract
The human herpesviruses (HHVs) are classified into the following three subfamilies: Alphaherpesvirinae, Betaherpesvirinae, and Gammaherpesvirinae. These HHVs have distinct pathological features, while containing a highly conserved viral replication pathway. Among HHVs, the basic viral particle structure and the sequential processes of viral replication are nearly identical. In particular, the capsid formation mechanism has been proposed to be highly similar among herpesviruses, because the viral capsid-organizing proteins are highly conserved at the structural and functional levels. Herpesviruses form capsids containing the viral genome in the nucleus of infected cells during the lytic phase, and release infectious virus (i.e., virions) to the cell exterior. In the capsid formation process, a single-unit-length viral genome is encapsidated into a preformed capsid. The single-unit-length viral genome is produced by cleavage from a viral genome precursor in which multiple unit-length viral genomes are tandemly linked. This encapsidation and cleavage is carried out by the terminase complex, which is composed of viral proteins. Since the terminase complex-mediated encapsidation and cleavage is a virus-specific mechanism that does not exist in humans, it may be an excellent inhibitory target for anti-viral drugs with high virus specificity. This review provides an overview of the functions of the terminase complexes of HHVs.
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Affiliation(s)
- Yuki Iwaisako
- Department of Cell Biology, Kyoto Pharmaceutical University
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2
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Jagtap AD, Geraghty RJ, Wang Z. Inhibiting HCMV pUL89-C Endonuclease with Metal-Binding Compounds. J Med Chem 2023; 66:13874-13887. [PMID: 37827528 DOI: 10.1021/acs.jmedchem.3c01280] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/14/2023]
Abstract
Human cytomegalovirus (HCMV) infects individuals of all ages and establishes a lifelong latency. Current antiviral drugs are suboptimal in efficacy and safety and ineffective against resistant/refractory HCMV. Therefore, there is an unmet clinical need for efficacious, safe, and mechanistically novel HCMV drugs. The recent Food and Drug Administration (FDA) approval of letermovir (LTV) validated the HCMV terminase complex as a new target for antiviral development. LTV targets terminase subunit pUL56 but not the main endonuclease enzymatic function housed in the C terminus of subunit pUL89 (pUL89-C). Structurally and mechanistically, pUL89-C is an RNase H-like viral endonuclease entailing two divalent metal ions at the active site. In recent years, numerous studies have extensively explored pUL89-C inhibition using metal-chelating chemotypes, an approach previously used for inhibiting HIV ribonuclease H (RNase H) and integrase strand transfer (INST). Collectively, the work summarized herein validates the use of metal-binding scaffolds for designing potent and specific pUL89-C inhibitors.
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Affiliation(s)
- Ajit Dhananjay Jagtap
- Center for Drug Design, College of Pharmacy, University of Minnesota, Minneapolis, Minnesota 55455, United States
| | - Robert J Geraghty
- Center for Drug Design, College of Pharmacy, University of Minnesota, Minneapolis, Minnesota 55455, United States
| | - Zhengqiang Wang
- Center for Drug Design, College of Pharmacy, University of Minnesota, Minneapolis, Minnesota 55455, United States
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3
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Muller C, Alain S, Hantz S. Identification of a leucine-zipper motif in pUL51 essential for HCMV replication and potential target for antiviral development. Antiviral Res 2023; 217:105673. [PMID: 37478917 DOI: 10.1016/j.antiviral.2023.105673] [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: 05/30/2023] [Revised: 07/12/2023] [Accepted: 07/13/2023] [Indexed: 07/23/2023]
Abstract
Human cytomegalovirus (HCMV) can cause serious diseases in immunocompromised patients. Use of current antivirals is limited by their adverse effects and emergence of drug resistance mutations. Thus, new drugs are an urgent need. The terminase complex (pUL56-pUL89-pUL51) represents a target of choice for new antivirals development. pUL51 was shown to be crucial for the cleavage of concatemeric HCMV DNA and viral replication. Its C-terminal part plays a critical role for the terminase complex assembly. However, no interaction domain is clearly identified. Sequence comparison of herpesvirus homologs and protein modelling were performed on pUL51. Importance of a putative interaction domain is validated by the generation of recombinant viruses with specific alanine substitutions of amino acids implicated in the domain. We identified a Leucine-Zipper (LZ) domain involving the leucine residues L126-X6-L133-X6-L140-X6-L147 in C-terminal part of pUL51. These leucines are crucial for viral replication, suggesting the significance for pUL51 structure and function. A mimetic-peptide approach has been used and tested in antiviral assays to validate the interaction domain as a new therapeutic target. Cytotoxicity was evaluated by LDH release measurement. The peptide TAT-HK29, homologous to the pUL51-LZ domain, inhibits HCMV replication by 27% ± 9% at 1.25 μM concentration without cytotoxicity. Our results highlight the importance of a leucine zipper domain in the C-terminal part of pUL51 involving leucines L126, L133, L140 and L147. We also confirm the potential of mimetic peptides to inhibit HCMV replication and the importance to target interaction domains to develop antiviral agents.
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Affiliation(s)
- Clotilde Muller
- Univ. Limoges, INSERM, CHU Limoges, RESINFIT, U1092, F-87000, Limoges, France
| | - Sophie Alain
- Univ. Limoges, INSERM, CHU Limoges, RESINFIT, U1092, F-87000, Limoges, France; CHU Limoges, Laboratoire de Bactériologie-Virologie-Hygiène, National Reference Center for Herpesviruses (NRCHV), F-87000, Limoges, France
| | - Sébastien Hantz
- Univ. Limoges, INSERM, CHU Limoges, RESINFIT, U1092, F-87000, Limoges, France; CHU Limoges, Laboratoire de Bactériologie-Virologie-Hygiène, National Reference Center for Herpesviruses (NRCHV), F-87000, Limoges, France.
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Zeng J, Cao D, Yang S, Jaijyan DK, Liu X, Wu S, Cruz-Cosme R, Tang Q, Zhu H. Insights into the Transcriptome of Human Cytomegalovirus: A Comprehensive Review. Viruses 2023; 15:1703. [PMID: 37632045 PMCID: PMC10458407 DOI: 10.3390/v15081703] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2023] [Revised: 08/03/2023] [Accepted: 08/04/2023] [Indexed: 08/27/2023] Open
Abstract
Human cytomegalovirus (HCMV) is a widespread pathogen that poses significant risks to immunocompromised individuals. Its genome spans over 230 kbp and potentially encodes over 200 open-reading frames. The HCMV transcriptome consists of various types of RNAs, including messenger RNAs (mRNAs), long non-coding RNAs (lncRNAs), circular RNAs (circRNAs), and microRNAs (miRNAs), with emerging insights into their biological functions. HCMV mRNAs are involved in crucial viral processes, such as viral replication, transcription, and translation regulation, as well as immune modulation and other effects on host cells. Additionally, four lncRNAs (RNA1.2, RNA2.7, RNA4.9, and RNA5.0) have been identified in HCMV, which play important roles in lytic replication like bypassing acute antiviral responses, promoting cell movement and viral spread, and maintaining HCMV latency. CircRNAs have gained attention for their important and diverse biological functions, including association with different diseases, acting as microRNA sponges, regulating parental gene expression, and serving as translation templates. Remarkably, HCMV encodes miRNAs which play critical roles in silencing human genes and other functions. This review gives an overview of human cytomegalovirus and current research on the HCMV transcriptome during lytic and latent infection.
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Affiliation(s)
- Janine Zeng
- Department of Microbiology and Molecular Genetics, New Jersey Medical School, Rutgers University, 225 Warren Street, Newark, NJ 070101, USA
| | - Di Cao
- Department of Pain Medicine, Huazhong University of Science and Technology Union Shenzhen Hospital, Shenzhen 518052, China
| | - Shaomin Yang
- Department of Pain Medicine, Huazhong University of Science and Technology Union Shenzhen Hospital, Shenzhen 518052, China
| | - Dabbu Kumar Jaijyan
- Department of Microbiology and Molecular Genetics, New Jersey Medical School, Rutgers University, 225 Warren Street, Newark, NJ 070101, USA
| | - Xiaolian Liu
- Institute of Pathogenic Organisms, Shenzhen Center for Disease Control and Prevention, Shenzhen 518055, China
| | - Songbin Wu
- Department of Pain Medicine, Huazhong University of Science and Technology Union Shenzhen Hospital, Shenzhen 518052, China
| | - Ruth Cruz-Cosme
- Department of Microbiology, Howard University College of Medicine, 520 W Street NW, Washington, DC 20059, USA
| | - Qiyi Tang
- Department of Microbiology, Howard University College of Medicine, 520 W Street NW, Washington, DC 20059, USA
| | - Hua Zhu
- Department of Microbiology and Molecular Genetics, New Jersey Medical School, Rutgers University, 225 Warren Street, Newark, NJ 070101, USA
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Almehmadi M, Haq IU, Alsaiari AA, Alshabrmi FM, Abdulaziz O, Allahyani M, Aladhadh M, Shafie A, Aljuaid A, Alotaibi RT, Ullah J, Alharthi NS. Identification of Small Molecule Inhibitors of Human Cytomegalovirus pUL89 Endonuclease Using Integrated Computational Approaches. Molecules 2023; 28:molecules28093938. [PMID: 37175348 PMCID: PMC10180037 DOI: 10.3390/molecules28093938] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2023] [Revised: 04/28/2023] [Accepted: 05/03/2023] [Indexed: 05/15/2023] Open
Abstract
Replication of Human Cytomegalovirus (HCMV) requires the presence of a metal-dependent endonuclease at the C-terminus of pUL89, in order to properly pack and cleave the viral genome. Therefore, pUL89 is an attractive target to design anti-CMV intervention. Herein, we used integrated structure-based and ligand-based virtual screening approaches in combination with MD simulation for the identification of potential metal binding small molecule antagonist of pUL89. In this regard, the essential chemical features needed for the inhibition of pUL89 endonuclease domain were defined and used as a 3D query to search chemical compounds from ZINC and ChEMBL database. Thereafter, the molecular docking and ligand-based shape screening were used to narrow down the compounds based on previously identified pUL89 antagonists. The selected virtual hits were further subjected to MD simulation to determine the intrinsic and ligand-induced flexibility of pUL89. The predicted binding modes showed that the compounds reside well in the binding site of endonuclease domain by chelating with the metal ions and crucial residues. Taken in concert, the in silico investigation led to the identification of potential pUL89 antagonists. This study provided promising starting point for further in vitro and in vivo studies.
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Affiliation(s)
- Mazen Almehmadi
- Department of Clinical Laboratory Sciences, College of Applied Medical Sciences, Taif University, Taif 21944, Saudi Arabia
| | - Ihtisham Ul Haq
- Department of Physical Chemistry and Technology of Polymers, Silesian University of Technology, M. Strzody 9, 44-100 Gliwice, Poland
- Joint Doctoral School, Silesian University of Technology, Akademicka 2A, 44-100 Gliwice, Poland
| | - Ahad Amer Alsaiari
- Department of Clinical Laboratory Sciences, College of Applied Medical Sciences, Taif University, Taif 21944, Saudi Arabia
| | - Fahad M Alshabrmi
- Department of Medical Laboratories, College of Applied Medical Sciences, Qassim University, Buraydah 51452, Saudi Arabia
| | - Osama Abdulaziz
- Department of Clinical Laboratory Sciences, College of Applied Medical Sciences, Taif University, Taif 21944, Saudi Arabia
| | - Mamdouh Allahyani
- Department of Clinical Laboratory Sciences, College of Applied Medical Sciences, Taif University, Taif 21944, Saudi Arabia
| | - Mohammed Aladhadh
- Department of Food Science and Human Nutrition, College of Agriculture and Veterinary Medicine, Qassim University, Buraydah 51452, Saudi Arabia
| | - Alaa Shafie
- Department of Clinical Laboratory Sciences, College of Applied Medical Sciences, Taif University, Taif 21944, Saudi Arabia
| | - Abdulelah Aljuaid
- Department of Clinical Laboratory Sciences, College of Applied Medical Sciences, Taif University, Taif 21944, Saudi Arabia
| | - Rema Turki Alotaibi
- Department of Clinical Laboratory Sciences, College of Applied Medical Sciences, Taif University, Taif 21944, Saudi Arabia
| | - Jawad Ullah
- Department of Chemistry, Hazara University, Mansehra 21120, Pakistan
| | - Nada Saud Alharthi
- Department of Clinical Laboratory Sciences, College of Applied Medical Sciences, Taif University, Taif 21944, Saudi Arabia
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Turner DL, Mathias RA. The human cytomegalovirus decathlon: Ten critical replication events provide opportunities for restriction. Front Cell Dev Biol 2022; 10:1053139. [PMID: 36506089 PMCID: PMC9732275 DOI: 10.3389/fcell.2022.1053139] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2022] [Accepted: 11/10/2022] [Indexed: 11/27/2022] Open
Abstract
Human cytomegalovirus (HCMV) is a ubiquitous human pathogen that can cause severe disease in immunocompromised individuals, transplant recipients, and to the developing foetus during pregnancy. There is no protective vaccine currently available, and with only a limited number of antiviral drug options, resistant strains are constantly emerging. Successful completion of HCMV replication is an elegant feat from a molecular perspective, with both host and viral processes required at various stages. Remarkably, HCMV and other herpesviruses have protracted replication cycles, large genomes, complex virion structure and complicated nuclear and cytoplasmic replication events. In this review, we outline the 10 essential stages the virus must navigate to successfully complete replication. As each individual event along the replication continuum poses as a potential barrier for restriction, these essential checkpoints represent potential targets for antiviral development.
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Affiliation(s)
- Declan L. Turner
- Department of Microbiology, Infection and Immunity Program, Monash Biomedicine Discovery Institute, Monash University, Melbourne, VIC, Australia
| | - Rommel A. Mathias
- Department of Microbiology, Infection and Immunity Program, Monash Biomedicine Discovery Institute, Monash University, Melbourne, VIC, Australia
- Department of Biochemistry and Molecular Biology, Monash University, Melbourne, VIC, Australia
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7
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Demin MV, Tikhomirov DS, Tupoleva TA, Filatov FP. [Resistance to antiviral drugs in human viruses from the subfamily Betaherpesvirinae]. Vopr Virusol 2022; 67:285-294. [PMID: 36515284 DOI: 10.36233/0507-4088-136] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2022] [Indexed: 12/07/2022]
Abstract
The review provides information on the mechanisms of the emergence of resistance to antiviral drugs in human viruses from the subfamily Betaherpesvirinae. Data on the principles of action of antiviral drugs and their characteristics are given. The occurrence rates of viral resistance in various groups of patients is described and information about the possible consequences of the emergence of resistance to antiviral drugs is given. Information is provided regarding the virus genes in which mutations occur that lead to viral resistance, and a list of such mutations that have described so far is given. The significance of the study of mutations leading to the resistance of the virus to antiviral drugs for medical practice is discussed.
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Affiliation(s)
- M V Demin
- National Medical Research Center of Hematology of the Ministry of Health of Russia
| | - D S Tikhomirov
- National Medical Research Center of Hematology of the Ministry of Health of Russia
| | - T A Tupoleva
- National Medical Research Center of Hematology of the Ministry of Health of Russia
| | - F P Filatov
- I.I. Mechnikov Research Institute of Vaccines and Serums of the Ministry of Education and Science of Russia.,National Research Center of Epidemiology and Microbiology named after Honorary Academician N.F. Gamaleya of the Ministry of Health of Russia
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8
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Deng J, Wang Q, Zhang J, Ma Y, Qi Y, Liu Z, Li Y, Ruan Q, Huang Y. Identification and characterization of human cytomegalovirus-encoded circular RNAs. Front Cell Infect Microbiol 2022; 12:980974. [PMID: 36452301 PMCID: PMC9702070 DOI: 10.3389/fcimb.2022.980974] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2022] [Accepted: 10/28/2022] [Indexed: 08/27/2023] Open
Abstract
Circular RNA (circRNA) exists extensively and plays essential roles in serving as microRNA (miRNA) or protein sponges and protein scaffolding in many organisms. However, the profiles and potential functions of the virus-encoded circRNA, including human cytomegalovirus (HCMV)-encoded circular RNAs, remain unclear. In the present study, HCMV-encoded circRNAs profile in human embryonic lung fibroblasts (HELF) with lytic infection was investigated using RNA deep sequencing and bioinformatics analysis. In total, 629 HCMV-encoded circRNAs were identified with various expression patterns in our results. The full sequences and alternative splicings of circUS12, circUL55, and circUL89 were verified by reverse transcriptase-PCR (RT-PCR) with divergent primers followed and Sanger sequencing. Transcription of circUL89 was validated by Northern blot. The HCMV-encoded circRNA-miRNA network analyses revealed the potential function of HCMV-encoded circRNAs during HCMV infection in HELFs. Collectively, HCMV infection deduced abundant HCMV-associated circRNAs during infection, and the HCMV-encoded circRNAs might play important roles in benefiting HCMV infection.
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Affiliation(s)
- Jingui Deng
- Department of Microorganism Laboratory, Shenyang Center for Disease Control and Prevention, Shenyang, China
- Virology Laboratory, Shengjing Hospital of China Medical University, Shenyang, China
| | - Qing Wang
- Virology Laboratory, Shengjing Hospital of China Medical University, Shenyang, China
| | - Jing Zhang
- Virology Laboratory, Shengjing Hospital of China Medical University, Shenyang, China
- Department of Pediatrics, Shengjing Hospital of China Medical University, Shenyang, China
- Department of Obstetrics and Gynecology, Shengjing Hospital of China Medical University, Shenyang, China
| | - Yanping Ma
- Virology Laboratory, Shengjing Hospital of China Medical University, Shenyang, China
- Department of Pediatrics, Shengjing Hospital of China Medical University, Shenyang, China
| | - Ying Qi
- Virology Laboratory, Shengjing Hospital of China Medical University, Shenyang, China
- Department of Pediatrics, Shengjing Hospital of China Medical University, Shenyang, China
- Department of Obstetrics and Gynecology, Shengjing Hospital of China Medical University, Shenyang, China
| | - Zhongyang Liu
- Virology Laboratory, Shengjing Hospital of China Medical University, Shenyang, China
- Department of Pediatrics, Shengjing Hospital of China Medical University, Shenyang, China
- Department of Obstetrics and Gynecology, Shengjing Hospital of China Medical University, Shenyang, China
| | - Yibo Li
- Department of Obstetrics and Gynecology, Shengjing Hospital of China Medical University, Shenyang, China
- Department of Obstetrics and Gynecology, Central Hospital Affiliated to Shenyang Medical College, Shenyang, China
| | - Qiang Ruan
- Virology Laboratory, Shengjing Hospital of China Medical University, Shenyang, China
- Department of Pediatrics, Shengjing Hospital of China Medical University, Shenyang, China
- Department of Obstetrics and Gynecology, Shengjing Hospital of China Medical University, Shenyang, China
| | - Yujing Huang
- Virology Laboratory, Shengjing Hospital of China Medical University, Shenyang, China
- Department of Pediatrics, Shengjing Hospital of China Medical University, Shenyang, China
- Department of Obstetrics and Gynecology, Shengjing Hospital of China Medical University, Shenyang, China
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Borst EM, Harmening S, Sanders S, Caragliano E, Wagner K, Lenac Roviš T, Jonjić S, Bosse JB, Messerle M. A Unique Role of the Human Cytomegalovirus Small Capsid Protein in Capsid Assembly. mBio 2022; 13:e0100722. [PMID: 36066102 PMCID: PMC9600257 DOI: 10.1128/mbio.01007-22] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2022] [Accepted: 08/11/2022] [Indexed: 11/20/2022] Open
Abstract
Morphogenesis of herpesvirus particles is highly conserved; however, the capsid assembly and genome packaging of human cytomegalovirus (HCMV) exhibit unique features. Examples of these include the essential role of the small capsid protein (SCP) and the existence of the β-herpesvirus-specific capsid-associated protein pp150. SCP and pp150, as well as the UL77 and UL93 proteins, are important capsid constituents, yet their precise mechanism of action is elusive. Here, we analyzed how deletion of the open reading frames (ORFs) encoding pUL77, pUL93, pp150, or SCP affects the protein composition of nuclear capsids. This was achieved by generating HCMV genomes lacking the respective genes, combined with a highly efficient transfection technique that allowed us to directly analyze these mutants in transfected cells. While no obvious effects were observed when pUL77, pUL93, or pp150 was missing, the absence of SCP impeded capsid assembly due to strongly reduced amounts of major capsid protein (MCP). Vice versa, when MCP was lacking, SCP became undetectable, indicating a mutual dependence of SCP and MCP for establishing appropriate protein levels. The SCP domain mediating stable MCP levels could be narrowed down to a C-terminal helix known to convey MCP binding. Interestingly, an SCP-EGFP (enhanced green fluorescent protein) fusion protein which also impaired the production of infectious progeny acted in a different manner, as capsid assembly was not abolished; however, SCP-EGFP-harboring capsids were devoid of DNA and trapped in paracrystalline nuclear structures. These results indicate that SCP is essential in HCMV because of its impact on MCP levels and reveal SCP as a potential target for antiviral inhibitors. IMPORTANCE Human cytomegalovirus (HCMV) is a ubiquitous pathogen causing life-threatening disease in immunocompromised individuals. Virus-specific processes such as capsid assembly and genome packaging can be exploited to design new antiviral strategies. Here, we report on a novel function of the HCMV small capsid protein (SCP), namely, ensuring stable levels of major capsid protein (MCP), thereby governing capsid assembly. Furthermore, we discovered a mutual dependence of the small and major capsid proteins to guarantee appropriate levels of the other respective protein and were able to pin down the SCP domain responsible for this effect to a region previously shown to mediate binding to the major capsid protein. In summary, our data contribute to the understanding of how SCP plays an essential part in the HCMV infection cycle. Moreover, disrupting the SCP-MCP interface may provide a starting point for the development of novel antiviral drugs.
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Affiliation(s)
- Eva Maria Borst
- Department of Virology, Hannover Medical School, Hannover, Germany
| | - Sarah Harmening
- Department of Virology, Hannover Medical School, Hannover, Germany
| | - Saskia Sanders
- Department of Virology, Hannover Medical School, Hannover, Germany
- Leibniz-Institute for Experimental Virology, Hamburg, Germany
- Centre for Structural Systems Biology, Hamburg, Germany
- Cluster of Excellence RESIST (EXC 2155), Hannover Medical School, Hannover, Germany
| | - Enrico Caragliano
- Department of Virology, Hannover Medical School, Hannover, Germany
- Leibniz-Institute for Experimental Virology, Hamburg, Germany
- Centre for Structural Systems Biology, Hamburg, Germany
- Cluster of Excellence RESIST (EXC 2155), Hannover Medical School, Hannover, Germany
| | - Karen Wagner
- Department of Virology, Hannover Medical School, Hannover, Germany
| | - Tihana Lenac Roviš
- Center for Proteomics, Faculty of Medicine, University of Rijeka, Rijeka, Croatia
| | - Stipan Jonjić
- Center for Proteomics, Faculty of Medicine, University of Rijeka, Rijeka, Croatia
| | - Jens Bernhard Bosse
- Department of Virology, Hannover Medical School, Hannover, Germany
- Leibniz-Institute for Experimental Virology, Hamburg, Germany
- Centre for Structural Systems Biology, Hamburg, Germany
- Cluster of Excellence RESIST (EXC 2155), Hannover Medical School, Hannover, Germany
| | - Martin Messerle
- Department of Virology, Hannover Medical School, Hannover, Germany
- German Center for Infection Research, Partner Site Hannover Braunschweig, Hannover, Germany
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10
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First clinical description of letermovir resistance mutation in cytomegalovirus UL51 gene and potential impact on the terminase complex structure. Antiviral Res 2022; 204:105361. [PMID: 35690130 DOI: 10.1016/j.antiviral.2022.105361] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2022] [Revised: 05/31/2022] [Accepted: 06/06/2022] [Indexed: 11/23/2022]
Abstract
BACKGROUND Letermovir (LMV) is a human cytomegalovirus (HCMV) terminase inhibitor indicated as prophylaxis for HCMV-positive stem-cell recipients. Its mechanism of action involves at least the viral terminase proteins pUL56, pUL89 and pUL51. Despite its efficiency, resistance mutations were characterized in vitro and in vivo, largely focused on pUL56. To date, mutations in pUL51 in clinical resistance remain to be demonstrated. METHODS The pUL51 natural polymorphism was described by sequencing 54 LMV-naive strains and was compared to UL51 HCMV genes from 16 patients non-responding to LMV therapy (prophylaxis or curative). Recombinant viruses were built by «en-passant» mutagenesis to measure the impact of the new mutations on antiviral activity and viral growth. Structure prediction was performed by homology modeling. The pUL51 final-model was analyzed and aligned with the atomic coordinates of the monomeric HSV-1 terminase complex (PDB:6M5R). RESULTS Among the 16 strains from treated-patients with LMV, 4 never described substitutions in pUL51 (D12E, 17del, A95V, V113L) were highlighted. These substitutions had no impact on viral fitness. Only UL51-A95V conferred 13.8-fold increased LMV resistance level by itself (IC50 = 29.246 ± 0.788). CONCLUSION As an isolated mutation in pUL51 in a clinical isolate can lead to LMV resistance, genotyping for resistance should involve sequencing of the pUL51, pUL56 and pUL89 genes. With terminase modelling, we make the hypothesis that LMV could bind to domains were UL56-L257I and UL51-A95V mutations were localized.
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11
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He T, Edwards TC, Xie J, Aihara H, Geraghty RJ, Wang Z. 4,5-Dihydroxypyrimidine Methyl Carboxylates, Carboxylic Acids, and Carboxamides as Inhibitors of Human Cytomegalovirus pUL89 Endonuclease. J Med Chem 2022; 65:5830-5849. [PMID: 35377638 PMCID: PMC9441020 DOI: 10.1021/acs.jmedchem.2c00203] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Human cytomegalovirus (HCMV) terminase complex entails a metal-dependent endonuclease at the C-terminus of pUL89 (pUL89-C). We report herein the design, synthesis, and characterization of dihydroxypyrimidine (DHP) acid (14), methyl ester (13), and amide (15) subtypes as inhibitors of HCMV pUL89-C. All analogs synthesized were tested in an endonuclease assay and a thermal shift assay (TSA) and subjected to molecular docking to predict binding affinity. Although analogs inhibiting pUL89-C in the sub-μM range were identified from all three subtypes, acids (14) showed better overall potency, substantially larger thermal shift, and considerably better docking scores than esters (13) and amides (15). In the cell-based antiviral assay, six analogs inhibited HCMV with moderate activities (EC50 = 14.4-22.8 μM). The acid subtype (14) showed good in vitro ADME properties, except for poor permeability. Overall, our data support the DHP acid subtype (14) as a valuable scaffold for developing antivirals targeting HCMV pUL89-C.
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Affiliation(s)
- Tianyu He
- Center for Drug Design, College of Pharmacy, University of Minnesota, Minneapolis, Minnesota 55455, United States
| | - Tiffany C Edwards
- Center for Drug Design, College of Pharmacy, University of Minnesota, Minneapolis, Minnesota 55455, United States
| | - Jiashu Xie
- Center for Drug Design, College of Pharmacy, University of Minnesota, Minneapolis, Minnesota 55455, United States
| | - Hideki Aihara
- Department of Biochemistry, Molecular Biology and Biophysics, University of Minnesota, Minneapolis, Minnesota 55455, United States
| | - Robert J Geraghty
- Center for Drug Design, College of Pharmacy, University of Minnesota, Minneapolis, Minnesota 55455, United States
| | - Zhengqiang Wang
- Center for Drug Design, College of Pharmacy, University of Minnesota, Minneapolis, Minnesota 55455, United States
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12
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Muller C, Alain S, Baumert TF, Ligat G, Hantz S. Structures and Divergent Mechanisms in Capsid Maturation and Stabilization Following Genome Packaging of Human Cytomegalovirus and Herpesviruses. Life (Basel) 2021; 11:life11020150. [PMID: 33669389 PMCID: PMC7920273 DOI: 10.3390/life11020150] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2020] [Revised: 02/11/2021] [Accepted: 02/12/2021] [Indexed: 01/13/2023] Open
Abstract
Herpesviruses are the causative agents of several diseases. Infections are generally mild or asymptomatic in immunocompetent individuals. In contrast, herpesvirus infections continue to contribute to significant morbidity and mortality in immunocompromised patients. Few drugs are available for the treatment of human herpesvirus infections, mainly targeting the viral DNA polymerase. Moreover, no successful therapeutic options are available for the Epstein–Barr virus or human herpesvirus 8. Most licensed drugs share the same mechanism of action of targeting the viral polymerase and thus blocking DNA polymerization. Resistances to antiviral drugs have been observed for human cytomegalovirus, herpes simplex virus and varicella-zoster virus. A new terminase inhibitor, letermovir, recently proved effective against human cytomegalovirus. However, the letermovir has no significant activity against other herpesviruses. New antivirals targeting other replication steps, such as capsid maturation or DNA packaging, and inducing fewer adverse effects are therefore needed. Targeting capsid assembly or DNA packaging provides additional options for the development of new drugs. In this review, we summarize recent findings on capsid assembly and DNA packaging. We also described what is known about the structure and function of capsid and terminase proteins to identify novels targets for the development of new therapeutic options.
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Affiliation(s)
- Clotilde Muller
- INSERM, CHU Limoges, University of Limoges, RESINFIT, U1092, 87000 Limoges, France; (C.M.); (S.A.)
| | - Sophie Alain
- INSERM, CHU Limoges, University of Limoges, RESINFIT, U1092, 87000 Limoges, France; (C.M.); (S.A.)
- CHU Limoges, Laboratoire de Bactériologie-Virologie-Hygiène, National Reference Center for Herpesviruses (NRCHV), 87000 Limoges, France
| | - Thomas F. Baumert
- Institut de Recherche sur les Maladies Virales et Hépatiques, Université de Strasbourg, 67000 Strasbourg, France;
- Institut Hospitalo-Universitaire, Pôle Hépato-Digestif, Nouvel Hôpital Civil, 67000 Strasbourg, France
| | - Gaëtan Ligat
- Institut de Recherche sur les Maladies Virales et Hépatiques, Université de Strasbourg, 67000 Strasbourg, France;
- Correspondence: (G.L.); (S.H.)
| | - Sébastien Hantz
- INSERM, CHU Limoges, University of Limoges, RESINFIT, U1092, 87000 Limoges, France; (C.M.); (S.A.)
- CHU Limoges, Laboratoire de Bactériologie-Virologie-Hygiène, National Reference Center for Herpesviruses (NRCHV), 87000 Limoges, France
- Correspondence: (G.L.); (S.H.)
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13
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Piret J, Boivin G. Antiviral Drugs Against Herpesviruses. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2021; 1322:1-30. [PMID: 34258735 DOI: 10.1007/978-981-16-0267-2_1] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
The discovery of the nucleoside analogue, acyclovir, represented a milestone in the management of infections caused by herpes simplex virus and varicella-zoster virus. Ganciclovir, another nucleoside analogue, was then used for the management of systemic and organ-specific human cytomegalovirus diseases. The pyrophosphate analogue, foscarnet, and the nucleotide analogue, cidofovir, have been approved subsequently and constitute the second-line antiviral drugs. However, the viral DNA polymerase is the ultimate target of all these antiviral agents with a possible emergence of cross-resistance between these drugs. Recently, letermovir that targets the viral terminase complex was approved for the prophylaxis of human cytomegalovirus infections in hematopoietic stem cell transplant recipients. Other viral targets such as the protein kinase and the helicase-primase complex are also evaluated for the development of novel potent inhibitors against herpesviruses.
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Affiliation(s)
| | - Guy Boivin
- CHU de Québec-Laval University, Quebec City, QC, Canada.
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14
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Marty FM, Ljungman PT, Chemaly RF, Wan H, Teal VL, Butterton JR, Yeh WW, Leavitt RY, Badshah CS. Outcomes of patients with detectable CMV DNA at randomization in the phase III trial of letermovir for the prevention of CMV infection in allogeneic hematopoietic cell transplantation. Am J Transplant 2020; 20:1703-1711. [PMID: 31883426 DOI: 10.1111/ajt.15764] [Citation(s) in RCA: 35] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2019] [Revised: 12/13/2019] [Accepted: 12/23/2019] [Indexed: 01/25/2023]
Abstract
Letermovir, a cytomegalovirus (CMV) terminase-complex inhibitor, is indicated for prophylaxis of CMV infection and disease in adult CMV-seropositive recipients of allogeneic hematopoietic cell transplantation (HCT). In a phase III, double-blind, randomized trial, letermovir significantly reduced the risk of clinically significant CMV infection (CS-CMVi) vs placebo through Week 24 post-HCT. This analysis investigated outcomes in participants with detectable CMV DNA at randomization, who were excluded from the primary efficacy analysis. In total, 70 of 565 randomized participants had detectable CMV DNA at randomization (letermovir 48; placebo 22). Study treatment completion rates were greater in letermovir-treated participants compared with placebo (52.1% vs 9.1%). The incidence of CS-CMVi or imputed primary endpoint events through Week 24 were 64.6% and 90.9% in the letermovir and placebo groups, respectively (treatment difference -26.1%; P = .010). Kaplan-Meier event rates for CS-CMVi onset through Week 14 (end-of-treatment period) were 33.1% for letermovir and 86.6% for placebo (P < .001). Median viral loads at the CS-CMVi events was similar in both treatment arms. All-cause mortality through Week 24 posttransplant was 15.0% for letermovir and 18.2% for placebo; through Week 48, mortality rates were 26.5% and 40.9%, respectively (P = .268). Overall, clinical outcomes were similar to those reported for participants with undetectable CMV DNA at randomization.
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Affiliation(s)
- Francisco M Marty
- Dana-Farber Cancer Institute and Brigham and Women's Hospital, Boston, Massachusetts
| | - Per T Ljungman
- Karolinska University Hospital and Karolinska Institutet, Stockholm, Sweden
| | - Roy F Chemaly
- MD Anderson Cancer Center, University of Texas, Houston, Texas
| | - Hong Wan
- Merck & Co., Inc., Kenilworth, New Jersey
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15
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Ligat G, Muller C, Alain S, Hantz S. [The terminase complex, a relevant target for the treatment of HCMV infection]. Med Sci (Paris) 2020; 36:367-375. [PMID: 32356713 DOI: 10.1051/medsci/2020063] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Human cytomegalovirus (HCMV) is an important ubiquitous opportunistic pathogen that belongs to the betaherpesviridae. Primary HCMV infection is generally asymptomatic in immunocompetent individuals. In contrast, HCMV infection causes serious disease in immunocompromised patients and is the leading cause of congenital viral infection. Although they are effective, the use of conventional molecules is limited by the emergence of resistance and by their toxicity. New antivirals targeting other replication steps and inducing fewer adverse effects are therefore needed. During HCMV replication, DNA packaging is performed by the terminase complex, which cleaves DNA to package the virus genome into the capsid. With no counterpart in mammalian cells, these terminase proteins are ideal targets for highly specific antivirals. A new terminase inhibitor, letermovir, recently proved effective against HCMV in phase III clinical trials. However, its mechanism of action is unclear and it has no significant activity against other herpesvirus or non-human CMV.
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Affiliation(s)
- Gaëtan Ligat
- Univ. Limoges, Inserm, CHU Limoges, RESINFIT, U1092, 87000 Limoges, France - CHU Limoges, Laboratoire de bactériologie-virologie-hygiène, Centre national de référence des Herpèsvirus (NRCHV), 87000 Limoges, France - Adresse actuelle : Inserm U1110, Institut de Recherche sur les Maladies Virales et Hépatiques, Université de Strasbourg, 3 rue Koeberlé, 67000 Strasbourg, France
| | - Clotilde Muller
- Univ. Limoges, Inserm, CHU Limoges, RESINFIT, U1092, 87000 Limoges, France - CHU Limoges, Laboratoire de bactériologie-virologie-hygiène, Centre national de référence des Herpèsvirus (NRCHV), 87000 Limoges, France
| | - Sophie Alain
- Univ. Limoges, Inserm, CHU Limoges, RESINFIT, U1092, 87000 Limoges, France - CHU Limoges, Laboratoire de bactériologie-virologie-hygiène, Centre national de référence des Herpèsvirus (NRCHV), 87000 Limoges, France
| | - Sébastien Hantz
- Univ. Limoges, Inserm, CHU Limoges, RESINFIT, U1092, 87000 Limoges, France - CHU Limoges, Laboratoire de bactériologie-virologie-hygiène, Centre national de référence des Herpèsvirus (NRCHV), 87000 Limoges, France
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16
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Abstract
PURPOSE OF REVIEW CMV DNA polymerase inhibitors such as ganciclovir and foscarnet have dramatically reduced the burden of CMV infection in the HCT recipient. However, their use is often limited by toxicities and resistance. Agents with novel mechanisms and favorable toxicity profiles are critically needed. We review recent developments in CMV antivirals and immune-based approaches to mitigating CMV infection. RECENT FINDINGS Letermovir, an inhibitor of the CMV terminase complex, was approved in 2017 for primary CMV prophylaxis in adult seropositive allogeneic HCT recipients. Maribavir, an inhibitor of the CMV UL97 kinase, is currently in two phase 3 treatment studies. Adoptive immunotherapy using third-party T cells has proven safe and effective in preliminary studies. Vaccine development continues, with several promising candidates currently under study. No longer limited to DNA polymerase inhibitors, the prevention and treatment of CMV infections in the HCT recipient is a rapidly evolving field which should translate into improvements in CMV-related outcomes.
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Affiliation(s)
- Morgan Hakki
- Division of Infectious Diseases, Department of Medicine, Oregon Health and Science University, 3181 SW Sam Jackson Park Road, Mail code L457, Portland, OR, 97239, USA.
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17
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Santos CAQ, Rhee Y, Czapka MT, Kazi AS, Proia LA. Make Sure You Have a Safety Net: Updates in the Prevention and Management of Infectious Complications in Stem Cell Transplant Recipients. J Clin Med 2020; 9:jcm9030865. [PMID: 32245201 PMCID: PMC7141503 DOI: 10.3390/jcm9030865] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2020] [Accepted: 03/11/2020] [Indexed: 12/11/2022] Open
Abstract
Hematopoietic stem cell transplant recipients are at increased risk of infection and immune dysregulation due to reception of cytotoxic chemotherapy; development of graft versus host disease, which necessitates treatment with immunosuppressive medications; and placement of invasive catheters. The prevention and management of infections in these vulnerable hosts is of utmost importance and a key “safety net” in stem cell transplantation. In this review, we provide updates on the prevention and management of CMV infection; invasive fungal infections; bacterial infections; Clostridium difficile infection; and EBV, HHV-6, adenovirus and BK infections. We discuss novel drugs, such as letermovir, isavuconazole, meropenem-vaborbactam and bezlotoxumab; weigh the pros and cons of using fluoroquinolone prophylaxis during neutropenia after stem cell transplantation; and provide updates on important viral infections after hematopoietic stem cell transplant (HSCT). Optimizing the prevention and management of infectious diseases by using the best available evidence will contribute to better outcomes for stem cell transplant recipients, and provide the best possible “safety net” for these immunocompromised hosts.
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18
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Advances in the genotypic diagnosis of cytomegalovirus antiviral drug resistance. Antiviral Res 2020; 176:104711. [PMID: 31940472 DOI: 10.1016/j.antiviral.2020.104711] [Citation(s) in RCA: 66] [Impact Index Per Article: 16.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2019] [Revised: 12/22/2019] [Accepted: 01/09/2020] [Indexed: 12/20/2022]
Abstract
Cytomegalovirus (CMV) drug resistance mutation maps are updated with recent information for polymerase inhibitors, the terminase inhibitor letermovir and the UL97 kinase inhibitor maribavir. Newly mapped mutations and their phenotypes provide more detail on cross-resistance properties and suggest the need to expand the CMV gene regions covered in diagnostic testing. Next-generation deep sequencing technology offers a more sensitive, higher resolution view of emerging antiviral resistance and is recommended for use in clinical trials. Issues of standardization and diagnostic utility in comparison with traditional Sanger sequencing remain unresolved. Quality control is important for the accurate and reproducible detection of mutant viral populations in clinical specimens.
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19
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Ye L, Qian Y, Yu W, Guo G, Wang H, Xue X. Functional Profile of Human Cytomegalovirus Genes and Their Associated Diseases: A Review. Front Microbiol 2020; 11:2104. [PMID: 33013768 PMCID: PMC7498621 DOI: 10.3389/fmicb.2020.02104] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2020] [Accepted: 08/10/2020] [Indexed: 12/18/2022] Open
Abstract
The human cytomegalovirus (HCMV), whose genome is 235 ± 1.9 kbp long, is a common herpesvirus. However, the functions of many of its genes are still unknown. HCMV is closely associated with various human diseases and infects 60-90% of the global population. It can infect various human cells, including fibroblasts, epithelial cells, endothelial cells, smooth muscle cells, and monocytes. Although HCMV infection is generally asymptomatic and causes subtle clinical symptoms, it can generate a robust immune response and establish a latent infection in immunocompromised individuals, including those with AIDS, transplant recipients, and developing fetuses. Currently available antivirals approved for the treatment of HCMV-associated diseases are limited by dose-limiting toxicity and the emergence of resistance; however, vaccines and immunoglobulins are unavailable. In this review, we have summarized the recent literature on 43 newly identified HCMV genes. We have described their novel functions on the viral replication cycle, latency, and host immune evasion. Further, we have discussed HCMV-associated diseases and current therapeutic targets. Our review may provide a foundational basis for studies aiming to prevent and develop targeted therapies for HCMV-associated diseases.
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Affiliation(s)
- Lele Ye
- Department of Gynecologic Oncology, Women’s Hospital, School of Medicine, Zhejiang University, Hangzhou, China
- Department of Microbiology and Immunology, Institute of Molecular Virology and Immunology, Institute of Tropical Medicine, School of Basic Medical Sciences, Wenzhou Medical University, Wenzhou, China
| | - Yunyun Qian
- First Clinical College, Wenzhou Medical University, Wenzhou, China
| | - Weijie Yu
- First Clinical College, Wenzhou Medical University, Wenzhou, China
| | - Gangqiang Guo
- Department of Microbiology and Immunology, Institute of Molecular Virology and Immunology, Institute of Tropical Medicine, School of Basic Medical Sciences, Wenzhou Medical University, Wenzhou, China
| | - Hong Wang
- Department of Microbiology and Immunology, Institute of Molecular Virology and Immunology, Institute of Tropical Medicine, School of Basic Medical Sciences, Wenzhou Medical University, Wenzhou, China
- *Correspondence: Hong Wang, ; Xiangyang Xue,
| | - Xiangyang Xue
- Department of Microbiology and Immunology, Institute of Molecular Virology and Immunology, Institute of Tropical Medicine, School of Basic Medical Sciences, Wenzhou Medical University, Wenzhou, China
- *Correspondence: Hong Wang, ; Xiangyang Xue,
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20
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Theiß J, Sung MW, Holzenburg A, Bogner E. Full-length human cytomegalovirus terminase pUL89 adopts a two-domain structure specific for DNA packaging. PLoS Pathog 2019; 15:e1008175. [PMID: 31809525 PMCID: PMC6897398 DOI: 10.1371/journal.ppat.1008175] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2019] [Accepted: 10/30/2019] [Indexed: 02/07/2023] Open
Abstract
A key step in replication of human cytomegalovirus (HCMV) in the host cell is the generation and packaging of unit-length genomes into preformed capsids. The enzymes involved in this process are the terminases. The HCMV terminase complex consists of two terminase subunits, the ATPase pUL56 and the nuclease pUL89. A potential third component pUL51 has been proposed. Even though the terminase subunit pUL89 has been shown to be essential for DNA packaging and interaction with pUL56, it is not known how pUL89 mechanistically achieves sequence-specific DNA binding and nicking. To identify essential domains and invariant amino acids vis-a-vis nuclease activity and DNA binding, alanine substitutions of predicted motifs were analyzed. The analyses indicated that aspartate 463 is an invariant amino acid for the nuclease activity, while argine 544 is an invariant aa for DNA binding. Structural analysis of recombinant protein using electron microscopy in conjunction with single particle analysis revealed a curvilinear monomer with two distinct domains connected by a thinner hinge-like region that agrees well with the predicted structure. These results allow us to model how the terminase subunit pUL89’s structure may mediate its function. HCMV is a member of the herpesvirus family and represents a major human pathogen causing severe disease in newborns and immunocompromised patients for which the development of new non-nucleosidic antiviral agents are highly important. This manuscript focuses on DNA packaging, which is a target for development of new antivirals. The terminase subunit pUL89 is involved in this process. The paper presents the identification of DNA binding and nuclease motifs with invariant amino acids and highlights its first 3-D surface structure at approx. 3 nm resolution. At this resolution, the calculated 3-D surface structure matches well with the predicted structure. In conjunction with earlier studies it was possible to define structure-function relationships for the HCMV terminase subunit pUL89.
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Affiliation(s)
- Janine Theiß
- Institute of Virology, Charité - Universitätsmedizin Berlin, Berlin, Germany
| | - Min Woo Sung
- Department of Biochemistry and Molecular Biology, Oregon Health and Science University, Portland, Oregon, United States of America
| | - Andreas Holzenburg
- Department of Molecular Science, School of Medicine, The University of Texas Rio Grande Valley, Brownsville-Edinburg-Harlingen, Texas, United States of America
| | - Elke Bogner
- Institute of Virology, Charité - Universitätsmedizin Berlin, Berlin, Germany
- * E-mail:
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21
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Komatsu TE, Hodowanec AC, Colberg-Poley AM, Pikis A, Singer ME, O'Rear JJ, Donaldson EF. In-depth genomic analyses identified novel letermovir resistance-associated substitutions in the cytomegalovirus UL56 and UL89 gene products. Antiviral Res 2019; 169:104549. [DOI: 10.1016/j.antiviral.2019.104549] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2019] [Revised: 06/27/2019] [Accepted: 07/01/2019] [Indexed: 01/08/2023]
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22
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Cryo-EM structures of herpes simplex virus type 1 portal vertex and packaged genome. Nature 2019; 570:257-261. [PMID: 31142842 PMCID: PMC6732574 DOI: 10.1038/s41586-019-1248-6] [Citation(s) in RCA: 97] [Impact Index Per Article: 19.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2018] [Accepted: 04/26/2019] [Indexed: 11/28/2022]
Abstract
Herpesviruses are enveloped viruses prevalent in the human population, responsible for a host of pathologies ranging from cold sores to birth defects and cancers. They are characterized by a highly pressurized, T (triangulation number) = 16 pseudo-icosahedral capsid encapsidating a tightly packed dsDNA genome1–3. A key process in the herpesvirus life cycle involves the recruitment of an ATP-driven terminase to a unique portal vertex to recognize, package, and cleave concatemeric dsDNA, ultimately giving rise to a pressurized, genome-containing virion4,5. Though this process has been studied in dsDNA phages6–9—with which herpesviruses bear some similarities—a lack of high-resolution in situ structures of genome-packaging machinery has prevented the elucidation of how these multi-step reactions, which require close coordination among multiple actors, occur in an integrated environment. Thus, to better define the structural basis of genome packaging and organization in the prototypical herpesvirus, herpes simplex virus type 1 (HSV-1), we developed sequential localized classification and symmetry relaxation methods to process cryoEM images of HSV-1 virions, enabling us to decouple and reconstruct hetero-symmetric and asymmetric elements within the pseudo-icosahedral capsid. Here we show in situ structures of the unique portal vertex, genomic termini, and ordered dsDNA coils in the capsid spooled around a disordered dsDNA core. We identify tentacle-like helices and a globular complex capping the portal vertex not observed in phages, indicative of adaptations in the DNA-packaging process specific to herpesviruses. Finally, our atomic models of portal vertex elements reveal how the five-fold-related capsid accommodates symmetry mismatch imparted by the dodecameric portal—long a mystery in icosahedral viruses—and inform possible DNA sequence-recognition and headful-sensing pathways involved in genome packaging. Our work represents the first fully symmetry-resolved structure of a portal vertex and first atomic model of a portal complex in a eukaryotic virus.
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23
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Yang L, Yang Q, Wang M, Jia R, Chen S, Zhu D, Liu M, Wu Y, Zhao X, Zhang S, Liu Y, Yu Y, Zhang L, Chen X, Cheng A. Terminase Large Subunit Provides a New Drug Target for Herpesvirus Treatment. Viruses 2019; 11:v11030219. [PMID: 30841485 PMCID: PMC6466031 DOI: 10.3390/v11030219] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2018] [Revised: 02/23/2019] [Accepted: 02/27/2019] [Indexed: 12/26/2022] Open
Abstract
Herpesvirus infection is an orderly, regulated process. Among these viruses, the encapsidation of viral DNA is a noteworthy link; the entire process requires a powered motor that binds to viral DNA and carries it into the preformed capsid. Studies have shown that this power motor is a complex composed of a large subunit, a small subunit, and a third subunit, which are collectively known as terminase. The terminase large subunit is highly conserved in herpesvirus. It mainly includes two domains: the C-terminal nuclease domain, which cuts the viral concatemeric DNA into a monomeric genome, and the N-terminal ATPase domain, which hydrolyzes ATP to provide energy for the genome cutting and transfer activities. Because this process is not present in eukaryotic cells, it provides a reliable theoretical basis for the development of safe and effective anti-herpesvirus drugs. This article reviews the genetic characteristics, protein structure, and function of the herpesvirus terminase large subunit, as well as the antiviral drugs that target the terminase large subunit. We hope to provide a theoretical basis for the prevention and treatment of herpesvirus.
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Affiliation(s)
- Linlin Yang
- Institute of Preventive Veterinary Medicine, Sichuan Agricultural University, Chengdu 611130, Sichuan, China.
- Research Center of Avian Diseases, College of Veterinary Medicine, Sichuan Agricultural University, Chengdu 611130, Sichuan, China.
- Key Laboratory of Animal Disease and Human Health of Sichuan Province, Chengdu 611130, Sichuan, China.
| | - Qiao Yang
- Institute of Preventive Veterinary Medicine, Sichuan Agricultural University, Chengdu 611130, Sichuan, China.
- Research Center of Avian Diseases, College of Veterinary Medicine, Sichuan Agricultural University, Chengdu 611130, Sichuan, China.
- Key Laboratory of Animal Disease and Human Health of Sichuan Province, Chengdu 611130, Sichuan, China.
| | - Mingshu Wang
- Institute of Preventive Veterinary Medicine, Sichuan Agricultural University, Chengdu 611130, Sichuan, China.
- Research Center of Avian Diseases, College of Veterinary Medicine, Sichuan Agricultural University, Chengdu 611130, Sichuan, China.
- Key Laboratory of Animal Disease and Human Health of Sichuan Province, Chengdu 611130, Sichuan, China.
| | - Renyong Jia
- Institute of Preventive Veterinary Medicine, Sichuan Agricultural University, Chengdu 611130, Sichuan, China.
- Research Center of Avian Diseases, College of Veterinary Medicine, Sichuan Agricultural University, Chengdu 611130, Sichuan, China.
- Key Laboratory of Animal Disease and Human Health of Sichuan Province, Chengdu 611130, Sichuan, China.
| | - Shun Chen
- Institute of Preventive Veterinary Medicine, Sichuan Agricultural University, Chengdu 611130, Sichuan, China.
- Research Center of Avian Diseases, College of Veterinary Medicine, Sichuan Agricultural University, Chengdu 611130, Sichuan, China.
- Key Laboratory of Animal Disease and Human Health of Sichuan Province, Chengdu 611130, Sichuan, China.
| | - Dekang Zhu
- Institute of Preventive Veterinary Medicine, Sichuan Agricultural University, Chengdu 611130, Sichuan, China.
- Research Center of Avian Diseases, College of Veterinary Medicine, Sichuan Agricultural University, Chengdu 611130, Sichuan, China.
- Key Laboratory of Animal Disease and Human Health of Sichuan Province, Chengdu 611130, Sichuan, China.
| | - Mafeng Liu
- Institute of Preventive Veterinary Medicine, Sichuan Agricultural University, Chengdu 611130, Sichuan, China.
- Research Center of Avian Diseases, College of Veterinary Medicine, Sichuan Agricultural University, Chengdu 611130, Sichuan, China.
- Key Laboratory of Animal Disease and Human Health of Sichuan Province, Chengdu 611130, Sichuan, China.
| | - Ying Wu
- Institute of Preventive Veterinary Medicine, Sichuan Agricultural University, Chengdu 611130, Sichuan, China.
- Research Center of Avian Diseases, College of Veterinary Medicine, Sichuan Agricultural University, Chengdu 611130, Sichuan, China.
- Key Laboratory of Animal Disease and Human Health of Sichuan Province, Chengdu 611130, Sichuan, China.
| | - Xinxin Zhao
- Institute of Preventive Veterinary Medicine, Sichuan Agricultural University, Chengdu 611130, Sichuan, China.
- Research Center of Avian Diseases, College of Veterinary Medicine, Sichuan Agricultural University, Chengdu 611130, Sichuan, China.
- Key Laboratory of Animal Disease and Human Health of Sichuan Province, Chengdu 611130, Sichuan, China.
| | - Shaqiu Zhang
- Institute of Preventive Veterinary Medicine, Sichuan Agricultural University, Chengdu 611130, Sichuan, China.
- Research Center of Avian Diseases, College of Veterinary Medicine, Sichuan Agricultural University, Chengdu 611130, Sichuan, China.
- Key Laboratory of Animal Disease and Human Health of Sichuan Province, Chengdu 611130, Sichuan, China.
| | - Yunya Liu
- Institute of Preventive Veterinary Medicine, Sichuan Agricultural University, Chengdu 611130, Sichuan, China.
- Research Center of Avian Diseases, College of Veterinary Medicine, Sichuan Agricultural University, Chengdu 611130, Sichuan, China.
- Key Laboratory of Animal Disease and Human Health of Sichuan Province, Chengdu 611130, Sichuan, China.
| | - Yanling Yu
- Institute of Preventive Veterinary Medicine, Sichuan Agricultural University, Chengdu 611130, Sichuan, China.
- Research Center of Avian Diseases, College of Veterinary Medicine, Sichuan Agricultural University, Chengdu 611130, Sichuan, China.
- Key Laboratory of Animal Disease and Human Health of Sichuan Province, Chengdu 611130, Sichuan, China.
| | - Ling Zhang
- Institute of Preventive Veterinary Medicine, Sichuan Agricultural University, Chengdu 611130, Sichuan, China.
- Research Center of Avian Diseases, College of Veterinary Medicine, Sichuan Agricultural University, Chengdu 611130, Sichuan, China.
- Key Laboratory of Animal Disease and Human Health of Sichuan Province, Chengdu 611130, Sichuan, China.
| | - Xiaoyue Chen
- Research Center of Avian Diseases, College of Veterinary Medicine, Sichuan Agricultural University, Chengdu 611130, Sichuan, China.
- Key Laboratory of Animal Disease and Human Health of Sichuan Province, Chengdu 611130, Sichuan, China.
| | - Anchun Cheng
- Institute of Preventive Veterinary Medicine, Sichuan Agricultural University, Chengdu 611130, Sichuan, China.
- Research Center of Avian Diseases, College of Veterinary Medicine, Sichuan Agricultural University, Chengdu 611130, Sichuan, China.
- Key Laboratory of Animal Disease and Human Health of Sichuan Province, Chengdu 611130, Sichuan, China.
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24
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Piret J, Boivin G. Clinical development of letermovir and maribavir: Overview of human cytomegalovirus drug resistance. Antiviral Res 2019; 163:91-105. [PMID: 30690043 DOI: 10.1016/j.antiviral.2019.01.011] [Citation(s) in RCA: 54] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2018] [Revised: 01/17/2019] [Accepted: 01/18/2019] [Indexed: 01/28/2023]
Abstract
The prevention and treatment of human cytomegalovirus (HCMV) infections is based on the use of antiviral agents that currently target the viral DNA polymerase and that may cause serious side effects. The search for novel inhibitors against HCMV infection led to the discovery of new molecular targets, the viral terminase complex and the viral pUL97 kinase. The most advanced compounds consist of letermovir (LMV) and maribavir (MBV). LMV inhibits the cleavage of viral DNA and its packaging into capsids by targeting the HCMV terminase complex. LMV is safe and well tolerated and exhibits pharmacokinetic properties that allow once daily dosing. LMV showed efficacy in a phase III prophylaxis study in hematopoietic stem cell transplant (HSCT) recipients seropositive for HCMV. LMV was recently approved under the trade name Prevymis™ for prophylaxis of HCMV infection in adult seropositive recipients of an allogeneic HSCT. Amino acid substitutions conferring resistance to LMV selected in vitro map primarily to the pUL56 and rarely to the pUL89 and pUL51 subunits of the HCMV terminase complex. MBV is an inhibitor of the viral pUL97 kinase activity and interferes with the morphogenesis and nuclear egress of nascent viral particles. MBV is safe and well tolerated and has an excellent oral bioavailability. MBV was effective for the treatment of HCMV infections (including those that are refractory or drug-resistant) in transplant recipients in two phase II studies and is further evaluated in two phase III trials. Mutations conferring resistance to MBV map to the UL97 gene and can cause cross-resistance to ganciclovir. MBV-resistant mutations also emerged in the UL27 gene in vitro and could compensate for the inhibition of pUL97 kinase activity by MBV. Thus, LMV and probably MBV will broaden the armamentarium of antiviral drugs available for the prevention and treatment of HCMV infections.
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Affiliation(s)
- Jocelyne Piret
- Research Center in Infectious Diseases, CHU of Quebec and Laval University, Quebec City, QC, Canada
| | - Guy Boivin
- Research Center in Infectious Diseases, CHU of Quebec and Laval University, Quebec City, QC, Canada.
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Andronova VL. [Modern ethiotropic chemotherapy of human cytomegalovirus infection: clinical effectiveness, molecular mechanism of action, drug resistance, new trends and prospects. Part 2.]. Vopr Virusol 2019; 63:250-260. [PMID: 30641020 DOI: 10.18821/0507-4088-2018-63-6-250-260] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2017] [Accepted: 12/12/2017] [Indexed: 11/17/2022]
Abstract
A number of synthetic compounds, such as the nucleoside analog ganciclovir, its L-valine ester (a metabolic precursor of ganciclovir) and pyrophosphate analog foscarnet, are permitted for the treatment of HCMVrelated diseases in the WHO European Region. The viral DNA- polymerase is used by all these drugs as a biotarget. However, the usage of standard anti-CMV therapy is accompanied by severe side effects, as well as the development of drug resistance in the virus, mainly in conditions of immunodefciency. In this review, we focused on viral proteins of interest as new potential targets and their inhibitors, such as the inhibitor of human CMV terminology, lethermovir, which showed great activity in the third phase of clinical trials, inhibitors of viral cyclin-dependent kinase (maribavir, cyclopropavir) and a number of compounds exhibiting anti-HCMV-activity, undergoing only preclinical trials in the experiment. Inclusion of new anti-CMV agents that are active against GСV/PFA/CDV-resistant strains of CMV into standard prophylactic and therapeutic regimens, will allow to increase the effectiveness of anti-CMV therapy, including in cases when standard therapy is ineffective. Areas covered: the international databases such as A MEDLINE, PubMed, eLIBRARY.RU, ClinicalTrials.gov., etc. with the purpose of obtaining information on compounds showing selective action against the human cytomegalovirus, the most promising for the development of drugs.
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Affiliation(s)
- V L Andronova
- National Research Centre for Epidemiology and Microbiology named after the honorary academician N.F. Gamaleya, Moscow, 123098, Russian Federation
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26
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FRET-based assay using a three-way junction DNA substrate to identify inhibitors of human cytomegalovirus pUL89 endonuclease activity. Eur J Pharm Sci 2019; 127:29-37. [DOI: 10.1016/j.ejps.2018.10.016] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2018] [Revised: 10/15/2018] [Accepted: 10/16/2018] [Indexed: 02/06/2023]
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Ligat G, Cazal R, Hantz S, Alain S. The human cytomegalovirus terminase complex as an antiviral target: a close-up view. FEMS Microbiol Rev 2018; 42:137-145. [PMID: 29361041 PMCID: PMC5972660 DOI: 10.1093/femsre/fuy004] [Citation(s) in RCA: 60] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2017] [Accepted: 01/17/2018] [Indexed: 01/13/2023] Open
Abstract
Human cytomegalovirus (HCMV) is responsible for life-threatening infections in immunocompromised individuals and can cause serious congenital malformations. Available antivirals target the viral polymerase but are subject to cross-resistance and toxicity. New antivirals targeting other replication steps and inducing fewer adverse effects are therefore needed. During HCMV replication, DNA maturation and packaging are performed by the terminase complex, which cleaves DNA to package the genome into the capsid. Identified in herpesviruses and bacteriophages, and with no counterpart in mammalian cells, these terminase proteins are ideal targets for highly specific antivirals. A new terminase inhibitor, letermovir, recently proved effective against HCMV in phase III clinical trials, but the mechanism of action is unclear. Letermovir has no significant activity against other herpesvirus or non-human CMV. This review focuses on the highly conserved mechanism of HCMV DNA-packaging and the potential of the terminase complex to serve as an antiviral target. We describe the intrinsic mechanism of DNA-packaging, highlighting the structure-function relationship of HCMV terminase complex components.
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Affiliation(s)
- G Ligat
- Université Limoges, INSERM, CHU Limoges, UMR 1092, 2 rue Dr Marcland, 87000 Limoges, France.,CHU Limoges, Laboratoire de Bactériologie-Virologie-Hygiène, National Reference Center for Herpesviruses (NRHV), 2 avenue Martin Luther King, 87000 Limoges, France
| | - R Cazal
- Université Limoges, INSERM, CHU Limoges, UMR 1092, 2 rue Dr Marcland, 87000 Limoges, France.,CHU Limoges, Laboratoire de Bactériologie-Virologie-Hygiène, National Reference Center for Herpesviruses (NRHV), 2 avenue Martin Luther King, 87000 Limoges, France
| | - S Hantz
- Université Limoges, INSERM, CHU Limoges, UMR 1092, 2 rue Dr Marcland, 87000 Limoges, France.,CHU Limoges, Laboratoire de Bactériologie-Virologie-Hygiène, National Reference Center for Herpesviruses (NRHV), 2 avenue Martin Luther King, 87000 Limoges, France
| | - S Alain
- Université Limoges, INSERM, CHU Limoges, UMR 1092, 2 rue Dr Marcland, 87000 Limoges, France.,CHU Limoges, Laboratoire de Bactériologie-Virologie-Hygiène, National Reference Center for Herpesviruses (NRHV), 2 avenue Martin Luther King, 87000 Limoges, France
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Gentry BG, Bogner E, Drach JC. Targeting the terminase: An important step forward in the treatment and prophylaxis of human cytomegalovirus infections. Antiviral Res 2018; 161:116-124. [PMID: 30472161 DOI: 10.1016/j.antiviral.2018.11.005] [Citation(s) in RCA: 25] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2018] [Revised: 11/07/2018] [Accepted: 11/13/2018] [Indexed: 10/27/2022]
Abstract
A key step in the replication of human cytomegalovirus (HCMV) in the host cell is the generation and packaging of unit-length genomes into preformed capsids. Enzymes required for this process are so-called terminases, first described for double-stranded DNA bacteriophages. The HCMV terminase consists of the two subunits, the ATPase pUL56 and the nuclease pUL89, and a potential third component pUL51. The terminase subunits are essential for virus replication and are highly conserved throughout the Herpesviridae family. Together with the portal protein pUL104 they form a powerful biological nanomotor. It has been shown for tailed dsDNA bacteriophages that DNA translocation into preformed capsid needs an extraordinary amount of energy. The HCMV terminase subunit pUL56 provides the required ATP hydrolyzing activity. The necessary nuclease activity to cleave the concatemers into unit-length genomes is mediated by the terminase subunit pUL89. Whether this cleavage is mediated by site-specific duplex nicking has not been demonstrated, however, it is required for packaging. Binding to the portal is a prerequisite for DNA translocation. To date, it is a common view that during translocation the terminase moves along some domains of the DNA by a binding and release mechanism. These critical structures have proven to be outstanding targets for drugs to treat HCMV infections because corresponding structures do not exist in mammalian cells. Herein we examine the HCMV terminase as a target for drugs and review several inhibitors discovered by both lead-directed medicinal chemistry and by target-specific design. In addition to producing clinically active compounds the research also has furthered the understanding of the role and function of the terminase itself.
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Affiliation(s)
- Brian G Gentry
- Drake University College of Pharmacy and Health Sciences, 2507 University Ave., Des Moines, 50311, IA, USA.
| | - Elke Bogner
- Institute of Virology, Charité-Universitätsmedizin Berlin, Charitéplatz 1, 10117, Berlin, Germany.
| | - John C Drach
- University of Michigan School of Dentistry, 1101 N. University Ave., Ann Arbor, 48109, MI, USA.
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Britt WJ, Prichard MN. New therapies for human cytomegalovirus infections. Antiviral Res 2018; 159:153-174. [PMID: 30227153 DOI: 10.1016/j.antiviral.2018.09.003] [Citation(s) in RCA: 62] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2018] [Revised: 08/28/2018] [Accepted: 09/07/2018] [Indexed: 02/07/2023]
Abstract
The recent approval of letermovir marks a new era of therapy for human cytomegalovirus (HCMV) infections, particularly for the prevention of HCMV disease in hematopoietic stem cell transplant recipients. For almost 30 years ganciclovir has been the therapy of choice for these infections and by today's standards this drug exhibits only modest antiviral activity that is often insufficient to completely suppress viral replication, and drives the selection of drug-resistant variants that continue to replicate and contribute to disease. While ganciclovir remains the therapy of choice, additional drugs that inhibit novel molecular targets, such as letermovir, will be required as highly effective combination therapies are developed not only for the treatment of immunocompromised hosts, but also for congenitally infected infants. Sustained efforts, largely in the biotech industry and academia, have identified additional highly active lead compounds that have progressed into clinical studies with varying levels of success and at least two have the potential to be approved in the near future. Some of the new drugs in the pipeline inhibit new molecular targets, remain effective against isolates that have developed resistance to existing therapies, and promise to augment existing therapeutic regimens. Here, we will describe some of the unique features of HCMV biology and discuss their effect on therapeutic needs. Existing drugs will also be discussed and some of the more promising candidates will be reviewed with an emphasis on those progressing through clinical studies. The in vitro and in vivo antiviral activity, spectrum of antiviral activity, and mechanism of action of new compounds will be reviewed to provide an update on potential new therapies for HCMV infections that have progressed significantly in recent years.
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Affiliation(s)
- William J Britt
- Department of Pediatrics, University of Alabama School of Medicine, Birmingham AL 35233-1711, USA
| | - Mark N Prichard
- Department of Pediatrics, University of Alabama School of Medicine, Birmingham AL 35233-1711, USA.
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30
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A Guinea pig cytomegalovirus resistant to the DNA maturation inhibitor BDCRB. Antiviral Res 2018; 154:44-50. [PMID: 29649495 DOI: 10.1016/j.antiviral.2018.04.006] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2017] [Revised: 04/02/2018] [Accepted: 04/06/2018] [Indexed: 11/20/2022]
Abstract
Herpesvirus DNA packaging is an essential step in virion morphogenesis and an important target for antiviral development. The halogenated benzimidazole 2-bromo-5,6-dichloro-1-β-d-ribofuranosyl-1H-benzimidazole (BDCRB) was the first compound found to selectively disrupt DNA packaging. It has activity against human cytomegalovirus as well as guinea pig cytomegalovirus. The latter provides a useful small animal model for congenital cytomegalovirus infection. To better understand the mechanism by which BDCRB acts, a guinea pig cytomegalovirus resistant to BDCRB was derived and characterized. An L406P substitution occurred within GP89, a subunit of the complex that cleaves and packages DNA, but transfer of this mutation to an otherwise wild type genetic background did not confer significant BDCRB resistance. The resistant virus also had a 13.4-kb deletion that also appeared to be unrelated to BDCRB-resistance as a virus with a similar spontaneous deletion was sensitive to BDCRB. Lastly, the BDCRB-resistant virus exhibited a dramatic increase in the number of reiterated terminal repeats at both genomic termini. The mechanism that underlies this change in genome structure is not known but may relate to the duplication of terminal repeats that is associated with DNA cleavage and packaging. A model is presented in which BDCRB impairs the ability of terminase to recognize cleavage site sequences, but repeat arrays overcome this impairment by presenting terminase with multiple opportunities to recognize the correct cleavage site sequences that lie within the repeats. Further elucidation of this phenomenon should prove valuable for understanding the molecular basis of herpesvirus DNA maturation and the mechanism of action of this class of drugs.
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Metal-chelating 3-hydroxypyrimidine-2,4-diones inhibit human cytomegalovirus pUL89 endonuclease activity and virus replication. Antiviral Res 2018; 152:10-17. [DOI: 10.1016/j.antiviral.2018.01.015] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2017] [Revised: 01/22/2018] [Accepted: 01/31/2018] [Indexed: 11/17/2022]
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Milbradt J, Sonntag E, Wagner S, Strojan H, Wangen C, Lenac Rovis T, Lisnic B, Jonjic S, Sticht H, Britt WJ, Schlötzer-Schrehardt U, Marschall M. Human Cytomegalovirus Nuclear Capsids Associate with the Core Nuclear Egress Complex and the Viral Protein Kinase pUL97. Viruses 2018; 10:v10010035. [PMID: 29342872 PMCID: PMC5795448 DOI: 10.3390/v10010035] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2017] [Revised: 01/05/2018] [Accepted: 01/10/2018] [Indexed: 02/07/2023] Open
Abstract
The nuclear phase of herpesvirus replication is regulated through the formation of regulatory multi-component protein complexes. Viral genomic replication is followed by nuclear capsid assembly, DNA encapsidation and nuclear egress. The latter has been studied intensely pointing to the formation of a viral core nuclear egress complex (NEC) that recruits a multimeric assembly of viral and cellular factors for the reorganization of the nuclear envelope. To date, the mechanism of the association of human cytomegalovirus (HCMV) capsids with the NEC, which in turn initiates the specific steps of nuclear capsid budding, remains undefined. Here, we provide electron microscopy-based data demonstrating the association of both nuclear capsids and NEC proteins at nuclear lamina budding sites. Specifically, immunogold labelling of the core NEC constituent pUL53 and NEC-associated viral kinase pUL97 suggested an intranuclear NEC-capsid interaction. Staining patterns with phospho-specific lamin A/C antibodies are compatible with earlier postulates of targeted capsid egress at lamina-depleted areas. Important data were provided by co-immunoprecipitation and in vitro kinase analyses using lysates from HCMV-infected cells, nuclear fractions, or infectious virions. Data strongly suggest that nuclear capsids interact with pUL53 and pUL97. Combined, the findings support a refined concept of HCMV nuclear trafficking and NEC-capsid interaction.
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Affiliation(s)
- Jens Milbradt
- Institute for Clinical and Molecular Virology, Friedrich-Alexander University of Erlangen-Nürnberg, Erlangen 91054, Germany.
| | - Eric Sonntag
- Institute for Clinical and Molecular Virology, Friedrich-Alexander University of Erlangen-Nürnberg, Erlangen 91054, Germany.
| | - Sabrina Wagner
- Institute for Clinical and Molecular Virology, Friedrich-Alexander University of Erlangen-Nürnberg, Erlangen 91054, Germany.
| | - Hanife Strojan
- Institute for Clinical and Molecular Virology, Friedrich-Alexander University of Erlangen-Nürnberg, Erlangen 91054, Germany.
| | - Christina Wangen
- Institute for Clinical and Molecular Virology, Friedrich-Alexander University of Erlangen-Nürnberg, Erlangen 91054, Germany.
| | - Tihana Lenac Rovis
- Department of Histology and Embryology, Faculty of Medicine, University of Rijeka, Rijeka 51000, Croatia.
| | - Berislav Lisnic
- Department of Histology and Embryology, Faculty of Medicine, University of Rijeka, Rijeka 51000, Croatia.
| | - Stipan Jonjic
- Department of Histology and Embryology, Faculty of Medicine, University of Rijeka, Rijeka 51000, Croatia.
| | - Heinrich Sticht
- Division of Bioinformatics, Institute of Biochemistry, Friedrich-Alexander University of Erlangen-Nürnberg, Erlangen 91054, Germany.
| | - William J Britt
- Departments of Pediatrics and Microbiology, School of Medicine, University of Alabama at Birmingham, Birmingham, AL 35294, USA.
| | | | - Manfred Marschall
- Institute for Clinical and Molecular Virology, Friedrich-Alexander University of Erlangen-Nürnberg, Erlangen 91054, Germany.
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Neuber S, Wagner K, Messerle M, Borst EM. The C-terminal part of the human cytomegalovirus terminase subunit pUL51 is central for terminase complex assembly. J Gen Virol 2018; 99:119-134. [DOI: 10.1099/jgv.0.000984] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023] Open
Affiliation(s)
- Sebastian Neuber
- Institute of Virology, Hannover Medical School, Hannover, Germany
| | - Karen Wagner
- Institute of Virology, Hannover Medical School, Hannover, Germany
| | - Martin Messerle
- Institute of Virology, Hannover Medical School, Hannover, Germany
| | - Eva Maria Borst
- Institute of Virology, Hannover Medical School, Hannover, Germany
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Chou S. A third component of the human cytomegalovirus terminase complex is involved in letermovir resistance. Antiviral Res 2017; 148:1-4. [PMID: 29107686 DOI: 10.1016/j.antiviral.2017.10.019] [Citation(s) in RCA: 67] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2017] [Revised: 10/23/2017] [Accepted: 10/27/2017] [Indexed: 12/17/2022]
Abstract
Letermovir is a human cytomegalovirus (CMV) terminase inhibitor that was clinically effective in a Phase III prevention trial. In vitro studies have shown that viral mutations conferring letermovir resistance map primarily to the UL56 component of the terminase complex and uncommonly to UL89. After serial culture of a baseline CMV laboratory strain under letermovir, mutation was observed in a third terminase component in 2 experiments, both resulting in amino acid substitution P91S in gene UL51 and adding to a pre-existing UL56 mutation. Recombinant phenotyping indicated that P91S alone conferred 2.1-fold increased letermovir resistance (EC50) over baseline, and when combined with UL56 mutation S229F or R369M, multiplied the level of resistance conferred by those mutations by 3.5-7.7-fold. Similarly a combination of UL56 mutations S229F, L254F and L257I selected in the same experiment conferred 54-fold increased letermovir EC50 over baseline, but 290-fold when combined with UL51 P91S. The P91S mutant was not perceptibly growth impaired. Although pUL51 is essential for normal function of the terminase complex, its biological significance is not well understood. Letermovir resistance mutations mapping to 3 separate genes, and their multiplier effect on the level of resistance, suggest that the terminase components interactively contribute to the structure of a letermovir antiviral target. The diagnostic importance of the UL51 P91S mutation arises from its potential to augment the letermovir resistance of some UL56 mutations at low fitness cost.
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Affiliation(s)
- Sunwen Chou
- Division of Infectious Diseases, Oregon Health and Science University, Department of Veterans Affairs Medical Center, Portland, OR, USA.
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