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Bottino P, Pastrone L, Curtoni A, Bondi A, Sidoti F, Zanotto E, Cavallo R, Solidoro P, Costa C. Antiviral Approach to Cytomegalovirus Infection: An Overview of Conventional and Novel Strategies. Microorganisms 2023; 11:2372. [PMID: 37894030 PMCID: PMC10608897 DOI: 10.3390/microorganisms11102372] [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: 08/28/2023] [Revised: 09/16/2023] [Accepted: 09/20/2023] [Indexed: 10/29/2023] Open
Abstract
Human cytomegalovirus (HCMV) is a herpesvirus capable of establishing a lifelong persistence in the host through a chronic state of infection and remains an essential global concern due to its distinct life cycle, mutations, and latency. It represents a life-threatening pathogen for immunocompromised patients, such as solid organ transplanted patients, HIV-positive individuals, and hematopoietic stem cell recipients. Multiple antiviral approaches are currently available and administered in order to prevent or manage viral infections in the early stages. However, limitations due to side effects and the onset of antidrug resistance are a hurdle to their efficacy, especially for long-term therapies. Novel antiviral molecules, together with innovative approaches (e.g., genetic editing and RNA interference) are currently in study, with promising results performed in vitro and in vivo. Since HCMV is a virus able to establish latent infection, with a consequential risk of reactivation, infection management could benefit from preventive treatment for critical patients, such as immunocompromised individuals and seronegative pregnant women. This review will provide an overview of conventional antiviral clinical approaches and their mechanisms of action. Additionally, an overview of proposed and developing new molecules is provided, including nucleic-acid-based therapies and immune-mediated approaches.
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Affiliation(s)
- Paolo Bottino
- Microbiology and Virology Unit, A.O.U. “Città della Salute e della Scienza di Torino”, 10126 Turin, Italy; (L.P.); (A.C.); (A.B.); (F.S.); (E.Z.); (R.C.)
| | - Lisa Pastrone
- Microbiology and Virology Unit, A.O.U. “Città della Salute e della Scienza di Torino”, 10126 Turin, Italy; (L.P.); (A.C.); (A.B.); (F.S.); (E.Z.); (R.C.)
| | - Antonio Curtoni
- Microbiology and Virology Unit, A.O.U. “Città della Salute e della Scienza di Torino”, 10126 Turin, Italy; (L.P.); (A.C.); (A.B.); (F.S.); (E.Z.); (R.C.)
| | - Alessandro Bondi
- Microbiology and Virology Unit, A.O.U. “Città della Salute e della Scienza di Torino”, 10126 Turin, Italy; (L.P.); (A.C.); (A.B.); (F.S.); (E.Z.); (R.C.)
| | - Francesca Sidoti
- Microbiology and Virology Unit, A.O.U. “Città della Salute e della Scienza di Torino”, 10126 Turin, Italy; (L.P.); (A.C.); (A.B.); (F.S.); (E.Z.); (R.C.)
| | - Elisa Zanotto
- Microbiology and Virology Unit, A.O.U. “Città della Salute e della Scienza di Torino”, 10126 Turin, Italy; (L.P.); (A.C.); (A.B.); (F.S.); (E.Z.); (R.C.)
| | - Rossana Cavallo
- Microbiology and Virology Unit, A.O.U. “Città della Salute e della Scienza di Torino”, 10126 Turin, Italy; (L.P.); (A.C.); (A.B.); (F.S.); (E.Z.); (R.C.)
| | - Paolo Solidoro
- Pneumology Unit, A.O.U. “Città della Salute e della Scienza di Torino”, 10126 Turin, Italy;
| | - Cristina Costa
- Microbiology and Virology Unit, A.O.U. “Città della Salute e della Scienza di Torino”, 10126 Turin, Italy; (L.P.); (A.C.); (A.B.); (F.S.); (E.Z.); (R.C.)
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Panda K, Parashar D, Viswanathan R. An Update on Current Antiviral Strategies to Combat Human Cytomegalovirus Infection. Viruses 2023; 15:1358. [PMID: 37376657 DOI: 10.3390/v15061358] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2023] [Revised: 05/29/2023] [Accepted: 06/06/2023] [Indexed: 06/29/2023] Open
Abstract
Human cytomegalovirus (HCMV) remains an essential global concern due to its distinct life cycle, mutations and latency. As HCMV is a herpesvirus, it establishes a lifelong persistence in the host through a chronic state of infection. Immunocompromised individuals are at risk of significant morbidity and mortality from the virus. Until now, no effective vaccine has been developed to combat HCMV infection. Only a few antivirals targeting the different stages of the virus lifecycle and viral enzymes are licensed to manage the infection. Therefore, there is an urgent need to find alternate strategies to combat the infection and manage drug resistance. This review will provide an insight into the clinical and preclinical antiviral approaches, including HCMV antiviral drugs and nucleic acid-based therapeutics.
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Affiliation(s)
- Kingshuk Panda
- Dengue-Chikungunya Group, Indian Council of Medical Research-National Institute of Virology, Pune 411001, India
| | - Deepti Parashar
- Dengue-Chikungunya Group, Indian Council of Medical Research-National Institute of Virology, Pune 411001, India
| | - Rajlakshmi Viswanathan
- Bacteriology Group, Indian Council of Medical Research-National Institute of Virology, Pune 411001, India
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Chang CC, Hsia KC. More than a zip code: global modulation of cellular function by nuclear localization signals. FEBS J 2020; 288:5569-5585. [PMID: 33296547 DOI: 10.1111/febs.15659] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2020] [Revised: 12/03/2020] [Accepted: 12/07/2020] [Indexed: 12/27/2022]
Abstract
Extensive structural and functional studies have been carried out in the field of nucleocytoplasmic transport. Nuclear transport factors, such as Importin-α/-β, recognize nuclear localization signals (NLSs) on cargo, and together with the small GTPase Ran, facilitate their nuclear localization. However, it is now emerging that binding of nuclear transport factors to NLSs not only mediates nuclear transport but also contributes to a variety of cellular functions in eukaryotes. Here, we describe recent advances that reveal how NLSs facilitate diverse cellular functions beyond nuclear transport activity. We review separately NLS-mediated regulatory mechanisms at different levels of biological organization, including (a) assembly of higher-order structures; (b) cellular organelle dynamics; and (c) modulation of cellular stress responses and viral infections. Finally, we provide mechanistic insights into how NLSs can regulate such a broad range of functions via their structural and biochemical properties.
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Affiliation(s)
- Chih-Chia Chang
- Institute of Molecular Biology, Academia Sinica, Taipei, Taiwan
| | - Kuo-Chiang Hsia
- Institute of Molecular Biology, Academia Sinica, Taipei, Taiwan.,Institute of Biochemistry and Molecular Biology, College of Life Sciences, National Yang-Ming University, Taipei, Taiwan
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Xu J, Cai Y, Jiang B, Li X, Jin H, Liu W, Kong Z, Hong J, Sealy JE, Iqbal M, Li Y. An optimized aptamer-binding viral tegument protein VP8 inhibits the production of Bovine Herpesvirus-1 through blocking nucleocytoplasmic shuttling. Int J Biol Macromol 2019; 140:1226-1238. [PMID: 31445153 DOI: 10.1016/j.ijbiomac.2019.08.165] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2019] [Revised: 08/18/2019] [Accepted: 08/19/2019] [Indexed: 10/26/2022]
Abstract
Bovine herpesvirus 1 (BoHV-1) is a major pathogen of infectious bovine rhinotracheitis in bovine. Previously, we generated the aptamer IBRV A4 using systemic evolution of ligands by exponential enrichment. This aptamer inhibited infectivity of BoHV-1 by blocking viral particle absorption onto cell membranes. In this study, we found that the major tegument protein VP8 of BoHV-1 was involved in inhibition of infectious virus production by IBRV A4. We improved the affinity of IBRV A4 for VP8 by optimizing aptamer's structure and repeat conformation. An optimized aptamer, IBRV A4.7, was constructed with quadruple binding sites and a new stem-loop structure, which had a stronger binding affinity for VP8 or BoHV-1 than raw aptamer IBRV A4. IBRV A4.7 bound to VP8 with a dissociation constant (Kd) value of 0.2054 ± 0.03948 nM and bound to BoHV-1 with a Kd value of 0.3637 ± 0.05452 nM. Crucially, IBRV A4.7 had improved antiviral activity compared to IBRV A4, with a half-maximal inhibitory concentration of 1.16 ± 0.042 μM. Our results also revealed IBRV A4.7 inhibited BoHV-1 production in MDBK cells through blocking nucleocytoplasmic shuttling of viral VP8 in BoHV-1-infected MDBK cells. In conclusion, the aptamer IBRV A4.7 may have potency in preventing outbreaks in herds due to reactivation of latency.
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Affiliation(s)
- Jian Xu
- Institute of Animal Husbandry and Veterinary Medicine, Beijing Academy of Agricultural and Forestry Sciences, Beijing 100097, PR China; Research Center for Infectious Disease in Livestock and Poultry, Beijing Academy of Agricultural and Forestry Sciences, Beijing 100097, PR China; Sino-UK Joint Laboratory for Prevention & Control of Infectious Diseases in Livestock and Poultry, Beijing 100097, PR China
| | - Yunhong Cai
- Institute of Animal Husbandry and Veterinary Medicine, Beijing Academy of Agricultural and Forestry Sciences, Beijing 100097, PR China; Research Center for Infectious Disease in Livestock and Poultry, Beijing Academy of Agricultural and Forestry Sciences, Beijing 100097, PR China; Sino-UK Joint Laboratory for Prevention & Control of Infectious Diseases in Livestock and Poultry, Beijing 100097, PR China
| | - Bo Jiang
- Institute of Animal Husbandry and Veterinary Medicine, Beijing Academy of Agricultural and Forestry Sciences, Beijing 100097, PR China; Research Center for Infectious Disease in Livestock and Poultry, Beijing Academy of Agricultural and Forestry Sciences, Beijing 100097, PR China; Sino-UK Joint Laboratory for Prevention & Control of Infectious Diseases in Livestock and Poultry, Beijing 100097, PR China
| | - Xiaoyang Li
- Institute of Animal Husbandry and Veterinary Medicine, Beijing Academy of Agricultural and Forestry Sciences, Beijing 100097, PR China; Research Center for Infectious Disease in Livestock and Poultry, Beijing Academy of Agricultural and Forestry Sciences, Beijing 100097, PR China; Sino-UK Joint Laboratory for Prevention & Control of Infectious Diseases in Livestock and Poultry, Beijing 100097, PR China
| | - Huan Jin
- Institute of Animal Husbandry and Veterinary Medicine, Beijing Academy of Agricultural and Forestry Sciences, Beijing 100097, PR China; Research Center for Infectious Disease in Livestock and Poultry, Beijing Academy of Agricultural and Forestry Sciences, Beijing 100097, PR China; Sino-UK Joint Laboratory for Prevention & Control of Infectious Diseases in Livestock and Poultry, Beijing 100097, PR China
| | - Wenxiao Liu
- Institute of Animal Husbandry and Veterinary Medicine, Beijing Academy of Agricultural and Forestry Sciences, Beijing 100097, PR China; Research Center for Infectious Disease in Livestock and Poultry, Beijing Academy of Agricultural and Forestry Sciences, Beijing 100097, PR China; Sino-UK Joint Laboratory for Prevention & Control of Infectious Diseases in Livestock and Poultry, Beijing 100097, PR China
| | - Zimeng Kong
- Institute of Animal Husbandry and Veterinary Medicine, Beijing Academy of Agricultural and Forestry Sciences, Beijing 100097, PR China; Research Center for Infectious Disease in Livestock and Poultry, Beijing Academy of Agricultural and Forestry Sciences, Beijing 100097, PR China; College of Animal Science and Technology, Jiangxi Agricultural University, Nanchang, Jiangxi 330045, PR China
| | - Jiabing Hong
- Institute of Animal Husbandry and Veterinary Medicine, Beijing Academy of Agricultural and Forestry Sciences, Beijing 100097, PR China; Research Center for Infectious Disease in Livestock and Poultry, Beijing Academy of Agricultural and Forestry Sciences, Beijing 100097, PR China; College of Animal Science and Technology, Jiangxi Agricultural University, Nanchang, Jiangxi 330045, PR China
| | - Joshua E Sealy
- Sino-UK Joint Laboratory for Prevention & Control of Infectious Diseases in Livestock and Poultry, Beijing 100097, PR China; The Pirbright Institute, Ash Rd, Pirbright, Woking GU24 0NF, United Kingdom
| | - Munir Iqbal
- Sino-UK Joint Laboratory for Prevention & Control of Infectious Diseases in Livestock and Poultry, Beijing 100097, PR China; The Pirbright Institute, Ash Rd, Pirbright, Woking GU24 0NF, United Kingdom
| | - Yongqing Li
- Institute of Animal Husbandry and Veterinary Medicine, Beijing Academy of Agricultural and Forestry Sciences, Beijing 100097, PR China; Research Center for Infectious Disease in Livestock and Poultry, Beijing Academy of Agricultural and Forestry Sciences, Beijing 100097, PR China; Sino-UK Joint Laboratory for Prevention & Control of Infectious Diseases in Livestock and Poultry, Beijing 100097, PR China.
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Zou X, Wu J, Gu J, Shen L, Mao L. Application of Aptamers in Virus Detection and Antiviral Therapy. Front Microbiol 2019; 10:1462. [PMID: 31333603 PMCID: PMC6618307 DOI: 10.3389/fmicb.2019.01462] [Citation(s) in RCA: 123] [Impact Index Per Article: 24.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2019] [Accepted: 06/11/2019] [Indexed: 12/19/2022] Open
Abstract
Viral infections can cause serious diseases for humans and animals. Accurate and early detection of viruses is often crucial for clinical diagnosis and therapy. Aptamers are mostly single-stranded nucleotide sequences that are artificially synthesized by an in vitro technology known as the Systematic Evolution of Ligands by Exponential Enrichment (SELEX). Similar to antibodies, aptamers bind specifically to their targets. However, compared with antibody, aptamers are easy to synthesize and modify and can bind to a broad range of targets. Thus, aptamers are promising for detecting viruses and treating viral infections. In this review, we briefly introduce aptamer-based biosensors (aptasensors) and describe their applications in rapid detection of viruses and as antiviral agents in treating infections. We summarize available data about the use of aptamers to detect and inhibit viruses. Furthermore, for the first time, we list aptamers specific to different viruses that have been screened out but have not yet been used for detecting viruses or treating viral infections. Finally, we analyze barriers and developing perspectives in the application of aptamer-based virus detection and therapeutics.
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Affiliation(s)
- Xinran Zou
- Department of Laboratory Medicine, The Affiliated People's Hospital, Jiangsu University, Zhenjiang, China.,Jiangsu Key Laboratory of Laboratory Medicine, Department of Immunology, School of Medicine, Jiangsu University, Zhenjiang, China
| | - Jing Wu
- Department of Laboratory Medicine, The Affiliated People's Hospital, Jiangsu University, Zhenjiang, China.,Jiangsu Key Laboratory of Laboratory Medicine, Department of Immunology, School of Medicine, Jiangsu University, Zhenjiang, China
| | - Jiaqi Gu
- Department of Laboratory Medicine, The Affiliated People's Hospital, Jiangsu University, Zhenjiang, China.,Jiangsu Key Laboratory of Laboratory Medicine, Department of Immunology, School of Medicine, Jiangsu University, Zhenjiang, China
| | - Li Shen
- Zhenjiang Center for Disease Control and Prevention, Jiangsu, China
| | - Lingxiang Mao
- Department of Laboratory Medicine, The Affiliated People's Hospital, Jiangsu University, Zhenjiang, China
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Abstract
Aptamers targeted to HIV reverse transcriptase (RT) have been demonstrated to inhibit RT in biochemical assays and as in cell culture. However, methods employed to date to evaluate viral suppression utilize time-consuming serial passage of infectious HIV in aptamer-expressing stable cell lines. We have established a rapid, transfection-based assay system to effectively examine the inhibitory potential of anti-HIV RT aptamers expressed between two catalytically inactive hammerhead ribozymes. Our system can be altered and optimized for a variety of cloning schemes, and addition of sequences of interest to the cassette is simple and straightforward. When paired with methods to analyze aptamer RNA accumulation and localization in cells and as packaging into pseudotyped virions, the method has a very high level of success in predicting good inhibitors.
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Regulated transport into the nucleus of herpesviridae DNA replication core proteins. Viruses 2013; 5:2210-34. [PMID: 24064794 PMCID: PMC3798897 DOI: 10.3390/v5092210] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2013] [Revised: 09/03/2013] [Accepted: 09/04/2013] [Indexed: 12/11/2022] Open
Abstract
The Herpesvirdae family comprises several major human pathogens belonging to three distinct subfamilies. Their double stranded DNA genome is replicated in the nuclei of infected cells by a number of host and viral products. Among the latter the viral replication complex, whose activity is strictly required for viral replication, is composed of six different polypeptides, including a two-subunit DNA polymerase holoenzyme, a trimeric primase/helicase complex and a single stranded DNA binding protein. The study of herpesviral DNA replication machinery is extremely important, both because it provides an excellent model to understand processes related to eukaryotic DNA replication and it has important implications for the development of highly needed antiviral agents. Even though all known herpesviruses utilize very similar mechanisms for amplification of their genomes, the nuclear import of the replication complex components appears to be a heterogeneous and highly regulated process to ensure the correct spatiotemporal localization of each protein. The nuclear transport process of these enzymes is controlled by three mechanisms, typifying the main processes through which protein nuclear import is generally regulated in eukaryotic cells. These include cargo post-translational modification-based recognition by the intracellular transporters, piggy-back events allowing coordinated nuclear import of multimeric holoenzymes, and chaperone-assisted nuclear import of specific subunits. In this review we summarize these mechanisms and discuss potential implications for the development of antiviral compounds aimed at inhibiting the Herpesvirus life cycle by targeting nuclear import of the Herpesvirus DNA replicating enzymes.
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Lange MJ, Sharma TK, Whatley AS, Landon LA, Tempesta MA, Johnson MC, Burke DH. Robust suppression of HIV replication by intracellularly expressed reverse transcriptase aptamers is independent of ribozyme processing. Mol Ther 2012; 20:2304-14. [PMID: 22948672 DOI: 10.1038/mt.2012.158] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022] Open
Abstract
RNA aptamers that bind human immunodeficiency virus 1 (HIV-1) reverse transcriptase (RT) also inhibit viral replication, making them attractive as therapeutic candidates and potential tools for dissecting viral pathogenesis. However, it is not well understood how aptamer-expression context and cellular RNA pathways govern aptamer accumulation and net antiviral bioactivity. Using a previously-described expression cassette in which aptamers were flanked by two "minimal core" hammerhead ribozymes, we observed only weak suppression of pseudotyped HIV. To evaluate the importance of the minimal ribozymes, we replaced them with extended, tertiary-stabilized hammerhead ribozymes with enhanced self-cleavage activity, in addition to noncleaving ribozymes with active site mutations. Both the active and inactive versions of the extended hammerhead ribozymes increased inhibition of pseudotyped virus, indicating that processing is not necessary for bioactivity. Clonal stable cell lines expressing aptamers from these modified constructs strongly suppressed infectious virus, and were more effective than minimal ribozymes at high viral multiplicity of infection (MOI). Tertiary stabilization greatly increased aptamer accumulation in viral and subcellular compartments, again regardless of self-cleavage capability. We therefore propose that the increased accumulation is responsible for increased suppression, that the bioactive form of the aptamer is one of the uncleaved or partially cleaved transcripts, and that tertiary stabilization increases transcript stability by reducing exonuclease degradation.
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Affiliation(s)
- Margaret J Lange
- Department of Molecular Microbiology and Immunology, University of Missouri, Columbia, MO, USA
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Sekimoto T, Yoneda Y. Intrinsic and extrinsic negative regulators of nuclear protein transport processes. Genes Cells 2012; 17:525-35. [PMID: 22672474 PMCID: PMC3444693 DOI: 10.1111/j.1365-2443.2012.01609.x] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2012] [Accepted: 03/27/2012] [Indexed: 12/31/2022]
Abstract
The nuclear-cytoplasmic protein transport is a critical process in cellular events. The identification of transport signals (nuclear localization signal and nuclear export signal) and their receptors has facilitated our understanding of this expanding field. Nuclear transport must be appropriately regulated to deliver proteins through the nuclear pore when their functions are required in the nucleus, and to export them into the cytoplasm when they are not needed in the nucleus. Altered nuclear transport processes have been observed in stressed cells, which would change gene expressions. Some viruses interfere with nuclear transport in host cells to evade immune defense. Moreover, certain transport factors negatively regulate nuclear protein transport in cells. Understanding the regulatory mechanisms of nuclear-cytoplasmic trafficking not only provides important information about cellular processes, but also is of use for developing specific inhibitors for transport pathways.
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Affiliation(s)
- Toshihiro Sekimoto
- Department of Biochemistry, Graduate School of Medicine, Osaka University, 1-3 Yamada-oka, Suita, Osaka, 565-0871, Japan
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Abstract
INTRODUCTION Cytomegalovirus (CMV) is a ubiquitous pathogen that establishes a lifelong asymptomatic infection in healthy individuals. Infection of immunesuppressed individuals causes serious illness. Transplant and AIDS patients are highly susceptible to CMV leading to life-threatening end-organ disease. Another vulnerable population is the developing fetus in utero, where congenital infection can result in surviving newborns with long-term developmental problems. There is no vaccine licensed for CMV and current antivirals suffer from complications associated with prolonged treatment. These include drug toxicity and emergence of resistant strains. There is an obvious need for new antivirals. Candidate intervention strategies are tested in controlled preclinical animal models but species specificity of human CMV precludes the direct study of the virus in an animal model. AREAS COVERED This review explores the current status of CMV antivirals and development of new drugs. This includes the use of animal models and the development of new improved models such as humanized animal CMV and bioluminescent imaging of virus in animals in real time. EXPERT OPINION Various new CMV antivirals are in development, some with greater spectrum of activity against other viruses. Although the greatest need is in the setting of transplant patients, there remains an unmet need for a safe antiviral strategy against congenital CMV. This is especially important as an effective CMV vaccine remains an elusive goal. In this regard, greater emphasis should be placed on suitable preclinical animal models and greater collaboration between industry and academia.
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Affiliation(s)
- Alistair McGregor
- University of Minnesota Medical School, Center for Infectious Diseases and Microbiology Translational Research, 2001 6th Street SE, MN 55455, USA.
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McGregor A, Choi KY, Schleiss MR. Guinea pig cytomegalovirus GP84 is a functional homolog of the human cytomegalovirus (HCMV) UL84 gene that can complement for the loss of UL84 in a chimeric HCMV. Virology 2010; 410:76-87. [PMID: 21094510 DOI: 10.1016/j.virol.2010.10.028] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2010] [Revised: 07/23/2010] [Accepted: 10/15/2010] [Indexed: 01/01/2023]
Abstract
The guinea pig cytomegalovirus (GPCMV) co-linear gene and potential functional homolog of HCMV UL84 (GP84) was investigated. The GP84 gene had delayed early transcription kinetics and transient expression studies of GP84 protein (pGP84) demonstrated that it targeted the nucleus and co-localized with the viral DNA polymerase accessory protein as described for HCMV pUL84. Additionally, pGP84 exhibited a transdominant inhibitory effect on viral growth as described for HCMV. The inhibitory domain could be localized to a minimal peptide sequence of 99 aa. Knockout of GP84 generated virus with greatly impaired growth kinetics. Lastly, the GP84 ORF was capable of complementing for the loss of the UL84 coding sequence in a chimeric HCMV. Based on this research and previous studies we conclude that GPCMV is similar to HCMV by encoding single copy co-linear functional homologs of HCMV UL82 (pp71), UL83 (pp65) and UL84 genes.
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Affiliation(s)
- A McGregor
- Center for Infectious Diseases and Microbiology, Translational Research and Division of Infectious Diseases, University of Minnesota Medical School, Department of Pediatrics, 2001 Sixth Street SE, Minneapolis, MN 55455, USA.
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Spector DJ, Yetming K. UL84-independent replication of human cytomegalovirus strain TB40/E. Virology 2010; 407:171-7. [PMID: 20855098 DOI: 10.1016/j.virol.2010.08.029] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2010] [Revised: 08/23/2010] [Accepted: 08/24/2010] [Indexed: 10/19/2022]
Abstract
The UL84 gene of human cytomegalovirus is implicated in the initiation of viral DNA replication during lytic infection. UL84 is essential for replication of a cloned viral origin of lytic replication (oriLyt) in vitro and mutants of strains AD169 or Towne with deletions or insertions in UL84 fail to grow in cells permissive for wild type virus. Here we show that UL84 is dispensable for replication of a strain TB40/E clone derived from a bacterial artificial chromosome. The genomes of the fibroblast-adapted strains AD169 and Towne are altered substantially from the consensus for strains that have not been propagated extensively in cell culture. The parental TB40/E genome conforms to the consensus genomic organization. Accordingly, natural HCMV strains may possess replication capability that extends beyond the known oriLyt-dependent replication system of laboratory strains.
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Affiliation(s)
- David J Spector
- Department of Microbiology and Immunology, College of Medicine, The Pennsylvania State University, Hershey, PA 17033, USA.
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